Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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31745 Publications
Proton modulated arc therapy for the treatment of left-sided breast cancer
Delso, N.; Stützer, K.; Kirk, M.; Huang, S.; Sanchez-Parcerisa, D.; Lin, L.; Freedman, G.; Metz, J.; Abel, E.; Carabe, A.;
Current proton techniques for left-sided breast cancer use an anterior or lateral anterior oblique (LAO) proton beam which places the distal edge of the beam immediately against the ipsilateral lung and the cardiac structures. Tangential proton modulated arc therapy (tPMAT) would place the distal edge within the target, reducing the dose and linear energy transfer (LET) to the lung, the heart or the left anterior descending (LAD) artery.

Six patients treated with a single LAO proton beam (sLAO), were re-planned using a tPMAT beam extending from the left lateral to the mediastinal side of the patient. The plans consisted of fifty mono-energetic beams, separated by 2o each. A custom wedge was devised for each patient to enable full target coverage. Dose and volume constraints for PTV, heart, lung, LAD in both treatment modalities were reported, and the statistical significance of their difference was determined using the t-test. LET distributions were calculated and reported for all patients. The robustness of both plan modalities were tested by calculating perturbed doses with isocenter shiftsof 3mm in all 6 principal directions and considering ±3.5% range uncertainty.

tPMAT showed equal or better capacity to cover the target with 95% of the dose while maintaining the dose below prescription for the organs at risk (OARs). The use of tPMAT reduces the LET in the OARs compared to the sLAO. tPMAT is also more robust to isocenter shifts and range uncertainties. A universal wedge can be used in tPMAT without changing the dosimetric or biophysical properties of the plan.

tPMAT provides robust dosimetric and biophysical benefits over the current sLAO technique. The possibility of using universal wedges indicates the possibility of doing tPMAT without altering the current fast turnaround of PBS planning and delivery.
Keywords: PMAT, breast cancer, uncertainty, proton therapy, LET
  • Lecture (Conference)
    Annual Meeting of the American Association for Physicists in Medicine 2017, 30.07.-03.08.2017, Denver, Colorado, USA

Publ.-Id: 25269 - Permalink


Thermoelectric Properties of Natural Chalcopyrite from Zacatecas, Mexico
Wyżga, P.; Bobnar, M.; Hennig, C.; Leithe-Jasper, A.; Mori, T.; Gumeniuk, R.;
The phase and chemical compositions of the mineral chalcopyrite from the sulphide footwall vein in La Cantera (Zacatecas, Mexico) is examined by powder x-ray diffraction, energy dispersive x-ray spectroscopy and chemical ICP-OES analyses. The influence of the detected impurities on the thermoelectric parameters (i.e. thermopower, electrical and thermal conductivities) is discussed. Thermoelectric figure of merit ZT of the studied natural minerals is found to be of the same order of magnitude (~ 10-3) as reported for CuFeS2 synthesized in the laboratory.
Keywords: chalcopyrite, powder x-ray diffraction, energy dispersive x-ray spectroscopy, ICP-OES

Publ.-Id: 25268 - Permalink


Surface charge and particle size determine the metabolic fate of dendritic polyglycerols
Pant, K.; Pufe, J.; Zarschler, K.; Bergmann, R.; Steinbach, J.; Reimann, S.; Haag, R.; Pietzsch, J.; Stephan, H.ORC
Dendritic polyglycerols (dPG) are water soluble, polyether-based nanomaterials which hold great potential in diagnostic as well as therapeutic applications. In order to translate them for in vivo applications, a systematic assessment regarding their cell and tissue interactions as well as their metabolic fate in vivo is a crucial step. Herein, we explore the structure-activity relationship of three different sizes (ca. 3, 5, and 10 nm) of neutral dendritic polyglycerol (dPG) and their corresponding negatively charged sulfate analogs (dPGS) on their in vitro and in vivo characteristics. Cellular metabolic activity was studied in A431 and HEK293 cells. Biomolecular corona formation was determined using electrophoretic mobility shift assay, which showed an increased protein binding of the dPGS even with serum concentrations as low as 20%. An in situ technique, microscale thermophoresis, was employed to address the binding affinities of these nanomaterials with serum proteins such as serum albumin, apo-transferrin, and fibrinogen. In addition, nanoparticle-cell interactions were studied in differentiated THP-1 cells which showed a charge dependent scavenger receptor-mediated uptake. In line with this data, detailed biodistribution and small animal PET imaging studies in Wistar rats using 68Ga-labeled dPG-/dPGS-NOTA conjugates showed that the neutral dPG-NOTA conjugates were quantitatively excreted via the kidneys with a subsequent hepatobiliary excretion with an increase in their size, whereas the polysulfated analogs (dPGS-NOTA) were sequestered preferentially in the liver and kidneys irrespective of their size. Taken together, this systematic study accentuates that the pharmacokinetics of dPGs is critically dependent on the overall size and charge and can be ‚fine-tuned’ for the intended requirements in nano-theranostics.

Publ.-Id: 25267 - Permalink


Experimental Investigation of Two-Phase Pipe Flow with Ultrafast X-ray Tomography and comparison with state-of-the-art CFD simulation
Banowski, M.; Hampel, U.; Krepper, E.; Beyer, M.; Lucas, D.;
In this paper, we report on experimental investigations of air/water two-phase flow in a vertical pipe, which is a benchmark experiment for the development and validation of two-phase CFD models and codes. We conducted experiments for co-current upward and downward flow as well as counter-current flow at ambient temperature and pressure conditions. As measurement technique, we employed ultrafast X-ray tomography, which gives two-dimensional cross-sectional images of the gas-liquid distribution in two planes up to 2500 Hz scanning speed. In this paper, we briefly explain this technique, introduce essential data processing steps and discuss the findings of the study.
Keywords: Two-phase flow, ultrafast X-ray tomography, pipe flow, gas holdup measurement, image processing, bubble size measurement, CFD code validation

Publ.-Id: 25266 - Permalink


A novel fuzzy-logic based method for determination of individual bubble velocity and size from dual-plane ultrafast X-ray tomography data of two-phase flow
Banowski, M.; Patmonoaji, A.; Lucas, D.; Hampel, U.;
Ultrafast X-ray tomography enables non-invasive imaging of gas-liquid flows with high spatial and temporal resolution. While it is relatively straightforward to extract e.g. gas fraction profiles from cross-sectional tomographic images, the extraction of bubble and gas-liquid interface information requires advanced image processing techniques. Thereby it is an important necessity to transform the temporal scale in the scanned sequences into a corresponding length scale for obtaining correct volumetric information. For bubbly flows this means that the velocity of the dispersed phase, i.e. the gas bubbles, has to be determined from dual-plane scans. A common and widely applied method to obtain gas phase velocities is cross-correlating the image sequences of the two scanning planes. This gives an averaged velocity for each position in the cross-section. In the present work, a new method is introduced, which determines the velocity of individual gas bubbles. This new method is termed as “bubble twinning method”, because it tries to identify twin-bubbles in both scanning planes. The developed algorithm compares essential bubble parameters, that is, volume, position and residence time in the slice, by applying a fuzzy-logic based membership function approach. The algorithm was tested for bubbly flow as well as slug flow conditions. Results are compared with established theoretical predictions as well as the cross-correlation method.
Keywords: Ultrafast X-ray tomography, image processing, bubbly flow, bubble velocity, bubble size

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  • Secondary publication expected

Publ.-Id: 25265 - Permalink


The uranium citric acid system and its sorption onto hematite
Steudtner, R.; Müller, K.; Schmeide, K.; Brendler, V.;
The determination and verification of thermodynamic and kinetic parameters of complexation, redox and sorption processes will improve the safety assessment of nuclear waste disposal sites. On one side, this study focusses on uranium complexation and redox reactions in aqueous citric acid solution as a function of reaction parameters (pH, c, T, atm.) and visible light irradiation. To evaluate the impact of these reaction parameters on the uranium – citric acid – water system i we used UV-Vis, ATR FT-IR and TRLF spectroscopy. In all systems the uranium citrate complexes were detected as dissolved species. We identified and characterized the formed complexes for uranium(VI) – (UO2)2(cit)22–, (UO2)2(cit)2(OH)3–, (UO2)2(cit)2(OH)24– and (UO2)3(cit)3(OH)55– as well as for uranium(IV) – U(H2cit)3+, U(Hcit)20 (aq.) and U(cit)22– and determined the corresponding complex formation constants. The determination and verification of thermodynamic and kinetic parameters of complexation and redox processes were consequently applied to the uranium sorption on hematite in the presence of citric acid.
The uranium reactions at the iron mineral − water interface were comprehensively investigated by in situ vibrational spectroscopy and classical batch sorption experiments. The uranium retention on hematite depends on pH value and citric acid concentration. By infrared spectroscopy, we observe a typical chemical binding of uranium by formation of an inner-sphere sorption complex in absence of citric acid. In presence of citric acid the sorption process is suppressed due to simultaneous complex formation in aqueous solution.
  • Lecture (Conference)
    GDCh-Wissenschaftsforum Chemie 2017, 11.-14.09.2017, Berlin, Deutschland

Publ.-Id: 25264 - Permalink


Numerical Investigation of Passive Heat Transfer to Ambient for Cooling of Nuclear Spent Fuel Pools
Unger, S.; Oertel, R.; Hampel, U.;
In current power plants is the storage of spent fuel in active cooled water pools standard practice. The reliability of nuclear power plants can be enhanced by substituting the active cooling components by passive heat transfer systems. A promising concept of such systems uses ambient air as an unlimited heat sink. However the major drawback of heat transfer towards air is a low heat transfer coefficients. To overcome this disadvantage a finned tube bundle heat exchanger, promote a natural convection cycle, is numerical investigated and thermohydraulic optimized. The most beneficial fin design on an oval shaped tube heat exchanger as well as a favourable chimney height could be established.
  • Contribution to proceedings
    48th Annual Meeting on Nuclear Technology, 16.-17.05.2017, Berlin, Deutschland
  • Lecture (Conference)
    48th Annual Meeting on Nuclear Technology, 16.-18.05.2017, Berlin, Deutschland

Publ.-Id: 25263 - Permalink


Validation and update of the baseline model for poly-disperse bubbly flows
Lucas, D.; Krepper, E.; Rzehak, R.; Ziegenhein, T.; Ma, T.; Liao, Y.;
For the consolidation of CFD-methods basing on the multi-fluid approach a baseline model strategy has been developed. Following this strategy a baseline model for poly-disperse bubbly flows was recently defined. This model is presented and an overview on the status as well as selected examples for the validation are given. Furthermore new developments regarding bubble induced turbulence, lateral lift force and bubble coalescence and breakup modelling are presented.
Keywords: baseline model, bubbly flow, CFD, bubble induced turbulence, lateral lift force, coalescence, breakup
  • Lecture (Conference)
    28th Meeting of the German CFD Network of Competence, 07.03.2017, Garching, Deutschland

Publ.-Id: 25262 - Permalink


Ultrasonic Measurements in a Model Experiment for Continuous Casting of Round Blooms with Magnetic Stirring in the Submerged Entry Nozzle
Schurmann, D.ORC; Willers, B.; Eckert, S.
We present an experimental study about the influence of magnetic stirring in the submerged entry nozzle (SEN) for continuous casting of round blooms performed at the mini-LIMMCAST facility at Helmholtz-Zentrum Dresden-Rossendorf (HZDR).
The experimental setup consists of a round mould with an inner diameter of 80 mm made of acrylic glass (PMMA), representing a mould used in industry. A magnetic field, employed by permanent magnets, rotates around the SEN with variable rotation frequencies. In our experiment we use a near eutectic alloy GaInSn under isothermal conditions as a model fluid, which is liquid at room temperature.
Measurements are carried out using ultrasonic velocity sensors by means of Ultrasound Doppler Velocimetry (UDV). The sensors are mounted directly at the SEN as well as on several positions along the mould, allowing us to have an insight into the effects by the magnetic stirring in the mould and in the SEN itself. We show a comparison of our results with measurements obtained at the same setup where the magnetic stirring in the SEN is replaced by electromagnetic stirring in the mould by means of a rotating magnetic field (RMF).
Keywords: MHD, magnetic stirring in the submerged entry nozzle (SEN), Ultrasonic Measurements (UDV) in GaInSn, Continuous Casting of Round Blooms
  • Contribution to proceedings
    9th ECCC "European Continuous Casting Conference", 26.-29.06.2017, Wien, Österreich
    Proceedings of the 9th ECCC
  • Lecture (Conference)
    9th ECCC "European Continuous Casting Conference", 29.06.2017, Wien, Österreich

Publ.-Id: 25261 - Permalink


High-energy resolution X-ray spectroscopy studies of electron-electron interactions in actinide and lanthanide systems
Kvashnina, K. O.; Rossberg, A.; Exner, J.; Scheinost, A. C.;
Two new synchrotron-based techniques, high energy resolution fluorescence detection (HERFD) X-ray absorption spectroscopy and resonant inelastic X-ray scattering (RIXS), can now provide unprecedented detailed information about the electronic structure of actinide and lanthanide bearing materials. This includes information on the electron-electron interactions, hybridization between molecular orbitals, the nature of their chemical bonding, and the occupation and the degree of the f-electron localization.

We have studied the electronic structure of cerium, lanthanum, praseodymium, uranium and thorium systems by means of HERFD and RIXS at The European Synchrotron (ESRF). The recently upgraded Rossendorf Beamline (ROBL) at ESRF dedicated to actinide science provides now a unique opportunity to measure HERFD and RIXS with a novel X-ray emission spectrometer with ground-breaking detection limits.

The recorded experimental spectral features were evaluated using a variety of theoretical codes including the LDA+U approximation within DFT, atomic multiplet theory and full multiple scattering FEFF. We furthermore show that RIXS and HERFD can be used to assess the degree of the f-electron localization and the (rather unpredictable) covalent or ionic nature of the actinide and lanthanide bonds. The combined experimental and theoretical data provide a fundamental understanding of lanthanide and actinide chemistry significant for topics of high societal relevance.
  • Lecture (Conference)
    Migration 2017, 10.-15.09.2017, Barcelona, Spain

Publ.-Id: 25260 - Permalink


High energy resolution X-ray spectroscopy studies of U intermetallics at the U M4,5 edges
Kvashnina, K.; Walker, H.; Magnani, N.; Lander, G.; Caciuffo, R.;
This contribution will provide an overview of applications of high energy resolution X-ray spectroscopic techniques to the U intermetallic systems. We will show resonant inelastic X-ray scattering (RIXS) and high energy resolution X-ray fluorescence detection (HERFD) X-ray absorption spectroscopy data from the uranium intermetallics UPd3, USb, USn3, URu2Si2 and others at the U M4,5 edges3 and compare the data to those from the well-localized 5f2 semiconductor UO2. We have found a small energy shift between UO2 and UPd3, both known to have localized 5f2 configurations, which we ascribe to the effect of conduction electrons in UPd3. The spectra from UPd3 and URu2Si2 are similar, strongly suggesting a predominant 5f2 configuration for URu2Si2. The valence-band RIXS provides information on the transitions (at about 18 eV) between the U 5f and U 6p states, as well as transitions of between 3 and 7 eV from the valence band into the unoccupied 5f states. These transitions are primarily involving mixed ligand states (O 2p or Pd, Ru 4d) and U 5f states. Calculations are able to reproduce both these low-energy transitions reasonably well.
We will demonstrate that two new synchrotron-based techniques – HERFD and RIXS at the actinide M4,5 edges – can now provide unprecedented detailed information on processes such as the electron-electron interactions, hybridization between molecular orbitals, the nature of their chemical bonding, and the occupation and the degree of the f-electron localization.
  • Invited lecture (Conferences)
    International Conference on Strongly Correlated Electron Systems, SCES 2017, 16.-21.07.2017, Prague, Czech Republic

Publ.-Id: 25259 - Permalink


Homogeneous gas-liquid distribution for monolithic structures via a needle distributor
Meitzner, C.; Hilpmann, G.; Schäfer, T.; Haase, S.; Lange, M.; Hampel, U.;
Structured catalysts are a widely discussed approach for process intensification of chemical multiphase reactors. But equal to common catalyst structures homogeneous educt distribution along the catalytic surface is mandatory for high reactor performance. Especially monolithic structures require a homogeneous initial fluid distribution. The current work presents a novel distribution concept for gas liquid flow through arbitrary channel matrices. It is based on the injection principle where gas and liquid are inserted directly into the channels. A prototype for different cell densities has been built and tested by using various measurement techniques: gravimetry, X-ray tomography and an optical fiber sensor. Additionally, the flow regime per channel has been detected as equal to single channel conditions.
Keywords: process intensification, multiphase reactions, phase distribution, structured catalysts, monolith

Publ.-Id: 25258 - Permalink


Ultrafast X-ray tomography for two-phase flow analysis in centrifugal pumps
Schäfer, T.; Hampel, U.;
The unsteady behavior of gas-liquid two-phase flow in a centrifugal pump impeller has been visualized, using ultrafast X-ray tomography. Based on the reconstructed tomographic images an evaluation and detailed analysis of the flow conditions has been done. Here, the high temporal resolution of the tomographic images offered the opportunity to get a deep insight into the flow to perform a detailed description of the transient gas-liquid phase distribution inside the impeller. Significant properties of the occurring two-phase flow and characteristic flow patterns have been disclosed. Furthermore, the effects of different air entrainment conditions have been investigated and typical phase distributions inside the impeller have been shown.
Keywords: centrifugal pump, gas entrainment, two-phase flow, ultrafast X-ray computed tomography
  • Lecture (Conference)
    48th Annual Meeting on Nuclear Technology (AMNT48), 16.-17.05.2017, Berlin, Deutschland
  • Contribution to proceedings
    48th Annual Meeting on Nuclear Technology (AMNT48), 16.-17.05.2017, Berlin, Deutschland
    Proceedings of 48th Annual Meeting on Nuclear Technology
  • atw - International Journal for Nuclear Power 62(2017)7, 474

Publ.-Id: 25257 - Permalink


Annual Report 2016 - Institute of Ion Beam Physics and Materials Research
Faßbender, J.ORC; Heera, V.; Helm, M.; Zahn, P.
Content:
Preface
Selected publications
Statistics
(Publications and patents, Concluded scientific degrees; Appointments and honors; Invited conference contributions, colloquia, lectures and talks; Conferences, workshops, colloquia and seminars; Exchange of researchers; Projects)
Doctoral training programme
Experimental equipment
User facilities and services
Organization chart and personnel
  • Open Access LogoWissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-078 2017

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Publ.-Id: 25256 - Permalink


The 2017 terahertz science and technology roadmap
Dhillon, S. S.; Vitiello, M. S.; Linfield, E. H.; Davies, A. G.; Hoffmann, M. C.; Booske, J.; Paoloni, C.; Gensch, M.; Weightman, P.; Williams, G. P.; Castro-Camus, E.; Cumming, D. R. S.; Simoens, F.; Escorcia-Carranza, I.; Grant, J.; Lucyszyn, S.; Kuwata-Gonokami, M.; Konishi, K.; Koch, M.; Schmuttenmaer, C. A.; Cocker, T. C.; Huber, R.; Markelz, A. G.; Taylor, Z. D.; Wallace, V. P.; Zeitler, J. A.; Sibik, J.; Korter, T. M.; Ellison, B.; Rea, S.; Goldsmith, P.; Cooper, K. B.; Appleby, R.; Pardo, D.; Huggard, P. G.; Krozer, V.; Shams, H.; Fice, M.; Renaud, C.; Seeds, A.; Stöhr, A.; Naftaly, M.; Ridler, N.; Clarke, R.; Cunningham, J. E.; Johnston, M. B.;
Science and technologies based on terahertz frequency electromagnetic radiation (100 GHz–30 THz) have developed rapidly over the last 30 years. For most of the 20th Century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to ‘real world’ applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2017, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 18 sections that cover most of the key areas of THz science and technology. We hope that The 2017 Roadmap on THz science and technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies.
Keywords: terahertz, time-domain spectroscopy, semiconductors

Publ.-Id: 25254 - Permalink


Radiomarkierung von Nanopartikeln
Franke, K.; Hildebrand, H.; Schymura, S.;
Nanoskalige Materialien halten zunehmend Einzug in verschiedenen Bereichen des alltäglichen Lebens. Viele Industrie- und Endverbraucherprodukte enthalten Nanopartikel, das betrifft u.a. den Gesundheitssektor, die Energie- und Umwelttechnik, den IT-Sektor, die Textilindustrie, die Automobilindustrie, die Chemie, die Bauindustrie aber auch Konsumgüter aus dem Lebensmittel- und Kosmetikbereich. Begleitet wird der wachsende Einsatz von Nanopartikeln von umfangreichen Studien zur Risikobewertung von Nanomaterialien. Bis heute sind jedoch viele erforderliche Aspekte für eine umfassende Gefährdungsabschätzung nur unzureichend bekannt. Eine wesentliche Ursache dafür ist die oft schwierige Identifizierung und Quantifizierung von Nanopartikeln in relevanten Testmedien und Zielkompartimenten, wie Böden, Sedimenten, Pflanzen oder Klärschlämmen. Mit der Radiomarkierung von Nanopartikeln steht jedoch eine effektive Methode zum Nachweis von Nanopartikeln in komplexen Umweltproben zur Verfügung, mit der es gelingt, radiomarkierte nanopartikuläre Spezies selektiv bei umweltrelevanten Nanopartikelkonzentrationen von anderen elementgleichen Spezies zu unterscheiden.
Wir haben verschieden Methoden zur Radiomarkierung von Nanopartikeln entwickelt, die es gestatten, abhängig von der Art der Nanopartikel und des zu untersuchenden Prozesses, gezielt Radiotracer in die Nanopartikel einzuführen. Wesentlich ist dabei oft die Möglichkeit, industriell genutzte bzw. kommerziell verfügbare Nanopartikel einer Radiomarkierung zu erschließen. Es wurden für die Radiomarkierung verschiedene Verfahren, wie die Synthese von Nanopartikeln unter Einsatz von radioaktiven Ausgangsstoffen, der chemischen Bindung von Radiotracern an Nanopartikel, die Aktivierung durch die Bestrahlung mit Protonen, die Rückstoßmarkierung und Diffusionsverfahren genutzt. Es ist möglich, durch die Auswahl geeigneter Radionuklide (Halbwertszeit, Zerfallsart) und die Einstellung der Aktivitätskonzentration gezielt die Eigenschaften der radiomarkierten Nanopartikel für verschiedene Nachweisverfahren und experimentelle Rahmenbedingungen (z.B. Zeitskala) einzustellen. In unseren aktuellen Arbeiten werden folgende radiomarkierte Nanopartikel hergestellt: [105Ag]Ag, [110mAg]Ag, [44Ti]TiO2, [45Ti]TiO2, [48V]TiO2, [64Cu]CuS, [64Cu]SiO2, [65Zn]CdSe/ZnS, [124I]CNTs, [125I]CNTs, [131I]CNTs, [7Be]MWCNT, [139Ce]CeO2 und [194Au]Pt. Begleitet werden die Arbeiten zur Radiomarkierung durch die Validierung der für die experimentellen Untersuchungen wesentlichen Eigenschaften der Nanopartikel.
Die radiomarkierten Nanopartikel werden in vielfältigen Studien z.B. im Bereich Bioverfügbarkeit (Pflanzenaufnahme), Transportverhalten, Abwasserbehandlung und in Verwitterungsuntersuchungen eingesetzt, Nachweisgrenzen im unteren ng/L-Bereich werden erreicht.
Keywords: Nanopartikel Radiomarkierung
  • Lecture (Conference)
    GDCh-Wissenschaftsforum Chemie 2017 ─ Jubiläumskongress "GDCh - 150 Jahre", 10.-14.09.2017, Berlin, Deutschland

Publ.-Id: 25253 - Permalink


U(VI) sorption by Ca-bentoniteunder alkaline and saline conditions as a function of pH and carbonate content
Philipp, T.; Schmeide, K.; Stumpf, T.;
Bentonite is considered as buffer and backfill material within the geo-technical barrier of such a repository. Therefore, profound understanding of the uranium retention processes in bentonite under environmentally relevant conditions is essential for long-term safety assessment. As the pore water chemistry of North German clay formations is characterized by high ionic strengths, corrosion of concrete present in the repository, is promoted. Upon corrosion, hyperalkaline (10 < pH < 13) cement pore waters evolve [3], which can alter the retention potential of bentonite towards radionuclides. Batch sorption experiments as a function of pH, c(U), SLR and carbonate content were conducted in combination with spectroscopic techniques such as time-resolved laser-induced fluorescence spectroscopy (TRLFS) and attenuated total reflectance Fourier-transform infrared (ATR FT-IR) spectroscopy in order to gain insight into the underlying processes on the macroscopic as well as on the molecular level. Lower U(VI) sorption in the presence of carbonate in the solution up to pH 9.5 can be explained with the formation of only weakly adsorbing uranyl carbonate species. TRLFS spectra verify the prevalence of these complexes already at low carbonate concentrations in the solution. In the pH region 10 – 12, an almost complete retention of U(VI) was observed in the absence as well as at low carbonate concentrations. TRLFS measurements reveal an abrupt change in U(VI) speciation at pH 10.5, to uranyl hydroxo complexes even at low carbonate concentrations (experiments at ambient atmosphere). TRLFS spectra suggest that anionic uranyl hydroxo complexes prevail in the pH region 10.5 – 12. Beside the adsorption of those, also precipitation processes are considered as a possible cause for the removal. pH-dependent U(VI) solubility tests have shown that the U(VI) retention in this pH region is apparently a combination of adsorption and precipitation processes. By contrast, at higher carbonate concentrations the U(VI) retention in the pH region 9.5 – 11 is very low . Under these conditions uranyl-carbonate complexes dominate the speciation up to pH 11.5. Consequently, the U(VI) speciation and the resulting sorption behavior in the (hyper)alkaline environment is highly dependent on the amount of carbonate in the solution.
  • Poster
    MIGRATION (16th International Conference on the Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere), 10.-15.09.2017, Barcelona, Spain

Publ.-Id: 25252 - Permalink


In-vivo Dosimetrie in der Partikeltherapie – eine Herausforderung für die öffentliche und industrielle Forschung
Pausch, G.ORC
Die Zerstörung bösartiger Tumoren mit hochenergetischen Ionenstrahlen ist mittlerweile ein klinisch etabliertes Verfahren der Radioonkologie. Allein in Deutschland gibt es sechs Zentren, in denen Patienten mit Protonen oder schwereren (Kohlenstoff-) Ionen bestrahlt werden können. Der entscheidende Vorteil gegenüber der klassischen Radiotherapie mit harter Röntgenstrahlung - die mögliche Schonung gesunden Gewebes in unmittelbarer Nachbarschaft des Zielgebiets, die bei Tumoren in der Nähe kritischer Organe überlebenswichtig sein kann – wird aber klinisch nicht voll ausgeschöpft, da die Vorhersage (Planung) der Reichweite von Ionenstrahlen mit Unsicherheiten behaftet ist. Die direkte und präzise Messung der Reichweite therapeutischer Partikelstrahlen im Körper (in vivo) ist ein Schlüsselproblem mit erheblichem Einfluss auf die Zukunft der Partikeltherapie, denn der hohe Aufwand muss sich am Ende in deutlich besseren Behandlungsergebnissen widerspiegeln.
Der Vortrag erläutert Ansätze und Erfolge bei der Entwicklung klinisch einsetzbarer Verfahren zur Reichweitemessung in der Partikeltherapie. Entsprechende Forschungsvorhaben profitieren von einer engen Zusammenarbeit der öffentlichen Forschung mit Industriepartnern. Der lange Weg von einer Idee über den Nachweis der Machbarkeit zum Prototypen eines Gerät und dem ersten Einsatz am Patienten kann wesentlich effektiver bewältigt werden, wenn komplementäre Kenntnisse, Erfahrungen, Herangehensweisen und Ressourcen in den verschiedenen Projektphasen abrufbar sind.
Keywords: Radioonkologie, radiooncology Partikeltherapie, particle therapy Reichweitemessung, range assessment
  • Invited lecture (Conferences)
    Jahrestagung der Deutschen Physikalischen Gesellschaft (DPG), AIW Industrietag, 30.03.2017, Münster, Deutschland

Publ.-Id: 25251 - Permalink


Self-Organized Semiconductor Surface Patterning of Pure and Compound Semiconductors by Polyatomic Ion Irradiation
Bischoff, L.; Böttger, R.; Pilz, W.; Facsko, S.; Heinig, K.-H.;
Irradiation of solids by heavy polyatomic ions (e.g. Aunm+ or Binm+) can cause localized melting at the ion impact point due to the enhanced energy density in the collision cascade of a polyatomic heavy ion impact [1,2]. Former studies demonstrated the formation of high aspect ratio, hexagonal dot patterns on Ge, Si or GaAs after high fluence, normal incidence irradiation using a mass separated FIB system choosing a suited combination of energy density deposition (i.e. poly- or monatomic ions) and substrate temperature, which facilitated transient melting of the ion collision cascade volume [2-5].
This study underscores the universality of this ion impact-melting-induced, self-organized pattern formation mechanism probing the compound semiconductor GaSb under polyatomic Aunm+ ion irradiation with various irradiation conditions in particular, ion species, fluence, energy/atom, temperature and angle of incidence.
Calculations of the needed melting energies per atom (Emelt) for different materials show, that among others GaSb is a preferring candidate for a successful surface patterning by mon- and polyatomic heavy ions whereas i.e. the surface of SiC remains stable under the given conditions.
HRSEM, AFM and EDX analysis of irradiated surfaces reveal that for compound semiconductors, additional superstructures are evolving on top of the regular semiconductor dot patterns, indicating superposition of a second dominant driving force for pattern self-organization.

[1] C. Anders et al., Phys. Rev. B 87 (2013) 245434.
[2] L. Bischoff et al., Nucl. Instr. Meth. Phys. Res. B 272 (2012) 198.
[3] R. Böttger et al., J. Vac. Sci Technol. B 30 (2012) 06FF12.
[4] R. Böttger et al., Phys. Stat. Sol. RRL 7 (2013) 501.
[5] L. Bischoff et al., Appl. Surf. Sci. 310 (2014) 154.
Keywords: Self-Organized Surface Patterning; Polyatomic Ion Irradiation; Focused ion Beam
  • Lecture (Conference)
    Raith-FIB- Workshop, 28.-30.03.2017, Dortmund, Germany

Publ.-Id: 25250 - Permalink


THEREDA –Thermodynamic Reference Database for the Nuclear Waste Disposal in Germany
Bok, F.; Moog, H. C.; Altmaier, M.; Voigt, W.; Thoenen, T.;
The disposal of nuclear waste including the assessment of long-term safety is still an open question in Germany. In addition to the still pending decision about the repository host rock (salt, granite, or clay) the basic necessity of a consistent and obligatory thermodynamic reference database persists. Such a database is essential to assess potential failure scenarios accurately and to make well-founded predictions about the long-term safety. Specific challenges are comprehensive datasets covering also high temperatures and salinities. Against this background, available databases do not suffice and are limited in their use, partly because of high restrictions and resulting incompleteness of reactions. Other databases rely on heterogeneous and therefore inconsistent data leading to incorrect model calculations. Due to these deficiencies THEREDA, a joint project of institutions leading in the field of safety research for nuclear waste disposal in Germany and Switzerland, was started in 2006.
THEREDA contains a relational databank whose structure has been designed in a way that promotes the internal consistency of thermodynamic data. Data considered cover the needs of Gibbs Energy Minimizers (ChemApp) and Law-of-Mass-Action programs (Geochemist’s Workbench, EQ3/6, PHREEQC) alike. Parameters for a variety of models describing interactions in mixed phases are included. Namely, the Pitzer parameters to describe activity coefficients of hydrated ions and molecules are considered. Both thermodynamic and interaction parameters can be described by temperature functions.
THEREDA offers evaluated thermodynamic data for many compounds (solid phases, aqueous species, or constituents of the gaseous phase) of elements relevant according to the present state of research. In particular, all oxidation states expected for disposal site conditions are covered.
Ready-to-use parameter files are created from the databank in a variety of formats (generic ASCII type, and formats required by the geochemical speciation codes) and offered to the users. They are also used for internal test calculations – one essential element of the quality assurance scheme. The results are documented and provided to the users.
THEREDA is accessible via internet through www.thereda.de. This is not only a portal to the database, but shall also serve as an information and discussion platform on issues concerning the database. Thus, we are confident to generate helpful feedback from the anticipated user community.
Keywords: THEREDA, Thermodynamic Reference Database
  • Lecture (Conference)
    21. European Conference on Thermophysical Properties, 03.-08.09.2017, Graz, Österreich

Publ.-Id: 25249 - Permalink


Characterization of tetravalent actinide complexes with imine type ligands (salen and its derivative)
Radoske, T.; März, J.; Kaden, P.; Walter, O.; Stumpf, T.; Ikeda-Ohno, A.ORC
Although the geochemistry of uranium is typically dominated by uranium(VI) (as UO22+), tetravalent uranium (U(IV)) could also occur under the geochemical conditions relevant to uranium mines or geological repositories of radioactive wastes, particularly under anaerobic conditions. In this context, the geochemical behaviour of U(IV) should be fully understood for the reliable safety/environmental assessment of such nuclear-related activities. The complexation and speciation of metal ions in groundwater is affected not only by inorganic ligands, but also many other natural organic ligands with a wide variety of different functional groups. Among the functionalities of naturally occurring organic ligands, oxygen(O)- and nitrogen(N)-donor groups play the most significant role in interacting with metal ions. The interaction of U(IV) with O- and N-donor ligands is, therefore, one of the fundamental information to understand the geochemical behaviour of uranium. Given this fact, this study focuses on the complexation of U(IV), as well as another tetravalent actinide of Th(IV), with the imine ligand salen and its derivative (Figure 1), which possess both O- and N-donor groups in the structure, as simplified model of naturally relevant organic O-/N-donor ligands. The complex structure in the solid state was determined by single crystal X-ray diffraction (SC-XRD), while the complexation in solution was studies by NMR and UV-visible absorption spectroscopy.
A series of single crystals of the U(IV)-salen complexes were obtained as a function of M:L ratio and pH by a liquid-liquid diffusion method. SC-XRD measurements on the obtained crystals revealed the new crystal structures, all showing the eight-fold coordination of the U centre with a trigonal dodecahedral geometry with the ligand on the primary coordination sphere of U.
UV-visible absorption measurements of U(IV)-salen solution as a function of M:L ratio indicate the existence of two independent solution species in the system, assigning as the U(IV)-salen complexes with the M:L ratios of 1:1 and 1:2. 1H-NMR spectra of solution samples in which the complex [UIV(Le)2] was dissolved indicate that the protons on the bridging ethyl group between the two imine groups show a significant high-field shift due to the paramagnetic effect of uranium(IV). The spectra also indicate that the metal is positioned at the centre of the coordination polyhedron formed by the two ligand molecules.
Keywords: uranium, imine, ligands, complex, thorium
  • Lecture (Conference)
    Migration 2017, 10.-15.09.2017, Barcelona, Spain

Publ.-Id: 25248 - Permalink


Universal CAR technology for redirection of human T cells to leukemic and solid tumor cells
Feldmann, A.; Bergmann, R.; Albert, S.; Arndt, C.; Aliperta, R.; Koristka, S.; Ehninger, A.; Cartellieri, M.; Ehninger, G.; Steinbach, J.; Bachmann, M.;
In recent years, adoptively transferred autologous human T cells that are genetically modified with chimeric antigen receptors (CARs) have been very successfully used for treatment of different hematological malignancies. However, immunotherapy of solid tumors seems to be more challenging. Especially for this application it is of great interest to enhance the very promising CAR technology.
Conventional CARs consist of (I) an extracellular single-chain fragment variable (scFv) redirected to a tumor-associated antigen (TAA), (II) a transmembrane region and (III) intracellular activating motifs. Although these CAR-armed T cells showed impressive therapeutic effects in leukemia patients, some limitations have appeared. Most importantly, CAR-armed T cells can cause life-threatening side effects as a consequence of immoderate on-target, on-tumor reactions or aggressive on-target, off-tumor attack against healthy tissues. Furthermore, under the pressure of a monospecific CAR therapy the targeted antigen can be reduced on tumor cells. To overcome these problems we have recently described a novel modular universal CAR (UniCAR) platform that consists of two separate arms: (I) the universal effector arm and (II) the individual targeting arm. T cells that are genetically modified with UniCARs are redirected to the short peptide epitope E5B9 that is physiologically not presented on the surface of living cells. E5B9 is coupled to the anti-TAA scFv of the target module (TM). Consequently, UniCAR T cells can be cross-linked to tumor cells via the TM which results in antigen-specific tumor cell killing.
We recently described a series of monospecific and bispecific TMs against TAAs including PSCA, PSMA, CD33, CD123, and EGFR (1-3). Here we summarize both in vitro and in experimental mice that all these TMs can efficiently redirect UniCAR T cells against tumor cells in a strictly target-dependent and target-specific manner. Killing occurred at pM TM concentrations. The killing efficacy of UniCAR T cells was comparable to conventional CAR T cells. Redirected UniCAR T cells released pro-inflammatory cytokines as measured by ELISA and/or flow cytometry-based multiplex assays including for example TNF, IL-2 and IFN-γ but not IL-6. In agreement with the UniCAR concept, TMs were released from UniCAR TM complexes in a concentration-dependent manner as measured by dynamic PET analysis.
In summary, we demonstrate that the reactivity of UniCAR-armed T cells can be switched on and off in the presence or absence of a variety of TMs against a series of different TAAs and thus supporting its high flexibility. Moreover, UniCAR activity can be regulated in a dose-dependent manner and thus improve the safety of the CAR technology.

1_A. Feldmann, C. Arndt, R. Bergmann, S. Loff, M. Cartellieri, D. Bachmann, R. Aliperta, M. Hetzenecker, F. Ludwig, S. Albert, P. Ziller-Walter, A. Kegler, S. Koristka, S. Gärtner, M. Schmitz, A. Ehninger, G. Ehninger, J. Pietzsch, J. Steinbach and M. Bachmann. Retargeting of T lymphocytes to PSCA- or PSMA positive prostate cancer cells using the novel modular chimeric antigen receptor platform technology “UniCAR”. Oncotarget 2017, in press.

2_S. Albert, C. Arndt, A. Feldmann, R. Bergmann, D. Bachmann, S. Koristka, F. Ludwig, P. Ziller-Walter, A. Kegler, S. Gärtner, M. Schmitz, A. Ehninger, M. Cartellieri, G. Ehninger, H.-J. Pietzsch, J. Pietzsch, J. Steinbach and M. Bachmann. A novel nanobody-based target module for retargeting of T lymphocytes to EGFR-expressing cancer cells via the modular UniCAR platform. OncoImmunology 2017, in press.

3_M. Cartellieri, A. Feldmann, S. Koristka, C. Arndt, S. Loff, A. Ehninger, M. von Bonin, EP Bejestani, G Ehninger and MP Bachmann. Switching CAR T cells on and off: a novel modular platform for retargeting of T cells to AML blasts. Blood Cancer J. 2016 Aug 12;6(8):e458. doi: 10.1038/bcj.2016.61.
  • Lecture (Conference)
    Cellular Therapy 2017, 9th International Symposium Erlangen, 16.-17.03.2017, Erlangen, Deutschland

Publ.-Id: 25247 - Permalink


Antigen-specific redirection of human regulatory T cells via a universally applicable chimeric antigen receptor technology
Kegler, A.; Koristka, S.; Feldmann, A.; Arndt, C.; Aliperta, R.; Albert, S.; Ziller-Walter, P.; Ehninger, G.; Bornhäuser, M.; Schmitz, M.; Bachmann, M.;
Regulatory T cells (Tregs) play a fundamental role in preventing inflammatory diseases and, therefore, their adoptive transfer emerged as a promising therapeutic strategy for the treatment of autoimmunity, graft rejection and Graft-versus-Host disease. However, preclinical animal models have already substantiated that the application of antigen-specific instead of polyclonal Tregs results in a far more efficient suppression of pathogenic immune reactions. Due to their low frequency in human peripheral blood, the isolation of Tregs with defined antigen specificity is a highly time-consuming and labour-intensive process that does not yet provide therapeutically relevant cell numbers. To overcome this obstacle, we equipped polyclonal Tregs with a novel modular chimeric antigen receptor (CAR) technology called UniCAR.
Unlike conventional CARs, the UniCAR binding domain does not directly recognize a target cell antigen but a small peptide epitope, which is a subunit of a separate target module (TM) providing antigen specificity. Hence, UniCAR-armed Tregs are silenced until they encounter the TM that mediates their cross-linkage with target cells. Therefore, this novel CAR technology not only allows for precise regulation of Treg activity between an “on” and “off” status but also enables their specific retargeting towards any desired antigen simply by replacing the TM.
To additionally compare the influence of different costimulatory signals on Treg properties and functionality, UniCARs were generated and introduced comprising either a CD3ζ, CD28-CD3ζ or CD137-CD3ζ signaling domain. For generation of UniCAR-expressing Tregs the CD45RA+ subpopulation was used, as these cells show the highest capacity in preserving Treg phenotype and functionality ex vivo.
Thus, highly pure, sorted CD4+CD25+CD127lowCD45RA+ Tregs were genetically modified by using a lentiviral gene transfer system resulting in an average of 80 % UniCAR+ Tregs. These UniCAR-armed Tregs maintain their phenotype (≥ 93 % FOXP3+) and expand approximately 150- to 200-fold already after 8 days of in vitro culture. In addition, in the presence of target cells and a respective TM the genetically modified Tregs are activated antigen-specifically as shown by CD69 and LAP upregulation as well as an increased FOXP3 expression level. Most importantly, upon TM-mediated restimulation via the UniCAR, Tregs efficiently suppress proliferation and overall expansion of bead-activated autologous T effector cells.
Taken together, our results underline the enormous clinical potential of UniCAR-armed Tregs as this technology facilitates an antigen-specific activation of polyclonal Tregs at the side of inflammation where they subsequently exert their suppressive capacity. In addition, the UniCAR system enables a precise control over Treg activity. Moreover, the UniCAR-equipped Tregs can be applied for treatment of a wide range of inflammation-related diseases as their antigen specificity can be easily modified just by exchanging the TM.
  • Poster
    Cellular Therapy 2017, 9th International Symposium Erlangen, 16.-17.03.2017, Erlangen, Deutschland

Publ.-Id: 25246 - Permalink


Scalable, multi-GPU photon tracing for in-situ X-ray radiation transport in solid density plasmas
Garten, M.ORC; Grund, A.; Huebl, A.; Burau, H.; Widera, R.; Kluge, T.; Fortmann-Grote, C.; Bussmann, M.
We present our scientific roadmap towards in-situ modeling of non-LTE interactions of XFEL type X-rays with solid density plasmas using a symbiosis of our performance portable, open source, 3D3V particle-in-cell (PIC) code PIConGPU and its X-ray tracing prototype ParaTAXIS. Treating radiation transport via various atomic processes will enable us to synthesize detector signals and gain predictive capabilities for upcoming pump-probe experiments at the European XFEL. With the world’s fastest particle-in-cell code PIConGPU and the raw computational power of the largest high performance computers we open up the possibility for large-scale case studies of unprecedented repeatability.
Keywords: ParaTAXIS, PIConGPU, radiation transport, plasma physics, atomic processes
  • Poster
    2017 Joint ICTP-IAEA School on Atomic Processes in Plasmas, 27.02.-03.03.2017, Trieste, Italia

Publ.-Id: 25245 - Permalink


Offshore floating packed bed reactors: Key challenges and potential solutions
Dashliborun, A. M.; Larachi, F.; Schubert, M.;
The influence of floating vessel motions on the hydrodynamic behavior of multiphase flows in porous media was studied. For elucidating their effects, laboratory-scale experiments were carried out using a hexapod ship motion emulator with six-degree-of-freedom motions with an embarked packed column operating in the co-current gas-liquid down-flow mode. The response of gas-liquid distribution, pressure drop, liquid saturation, and flow regime transition to column inclinations and roll motions was monitored and compared to those of the corresponding static vertical and inclined configurations. On-line visualization of two-phase flow patterns in terms of local liquid saturation distribution is performed by means of a capacitance wire-mesh sensor positioned firmly on the floating packed bed. The results revealed that the hydrodynamic performance of packed beds under roll motion deviates strongly from that of the static beds, indicating that the known characteristics of the conventional land-based trickle-bed reactors cannot be transposed on a one-to-one basis for design and scale-up of the floating reactor configurations.
Keywords: Offshore floating packed bed reactors; hydrodynamics; rolling motion; gas-liquid segregation; liquid saturation; flow regime transition

Publ.-Id: 25243 - Permalink


Structural clarification of a tert-butyl-calix[4]arene-based 8-hydroxyquinoline complex with uranium(VI) in non-aqueous solution
Bauer, A.; März, J.; Barthen, R.; Jäschke, A.; Glasneck, F.; Schmeide, K.; Brendler, V.; Kersting, B.; Stumpf, T.;
The actinides uranium and thorium are considered disturbing constituents in rare earth production. Thus they have to be removed, e.g. by extraction.[1] Due to their modifiable selectivity and solubility calix[n]arenes are interesting compounds for the extraction of uranium(VI).[2]
A new chalice-like tert-butyl-calix[4]arene-based 8-hydroxyquinoline ligand consisting of four phenolic units was synthesized. Tert-butyl substituents provide a hydrophobic character. Functionalizing of the phenolic hydroxyl groups by 8-hydroxyquinoline ensures the affinity to uranyl ions.[2]
For better process understanding we examined the mechanisms of uranyl complexation by the calix[4]arene derivative. The structure of the tert-butyl-calix[4]arene-based 8-hydroxyquinoline uranyl complex was unveiled by spectroscopy and isothermal titration calorimetry.
The complexation studies were performed in acetonitrile. Luminescence spectroscopic studies indicated the interaction of uranyl ions with the ligand. UV visible investigations evidenced the presence of a 1:1 and a 1:2 ligand uranyl complex with stability constants of log ß1:1 = 5.94 ± 0.02 and log ß1:2 = 6.33 ± 0.01. Isothermal titration calorimetry provided the thermodynamic characterization of the complexation.
Single crystal X-ray analysis of the 1:1 complex revealed the coordination of the uranyl ion via a N2O2 donor set (Fig. 1). The charge is compensated by an additional coordinated nitrate ion.
The application of electrospray ionization time-of-flight mass spectrometry affirmed the coordination of two hexavalent uranyl nitrate ions in acetonitrile.
In addition, to improve the understanding of the ligand complexation properties the interaction with thorium is studied.

References:

[1] Z. W. Zhu, Y. Pranolo, C.Y. Cheng, Miner Eng 2015, 77, 185.
[2] A. Jäschke, M. Kischel, A. Mansel, B. Kersting, Eur. J. Inorg. Chem. 2017, 894
Keywords: calix[4]arene, SE-FLECX, rare earth production, uranium, complexation studies
  • Poster
    GDCh - Wissenschaftsforum - Jahrestagung Fachgruppe Nuklearchemie, 10.-14.09.2017, Berlin, Deutschland

Publ.-Id: 25242 - Permalink


Big Bang 6Li nucleosynthesis studied deep underground
Trezzi, D.; Anders, M.; Aliotta, M.; Bellini, A.; Bemmerer, D.; Boeltzig, A.; Broggini, C.; Bruno, C. G.; Caciolli, A.; Corvisiero, F. C. P.; Costantini, H.; Davinson, T.; Depalo, R.; Elekes, Z.; Erhard, M.; Ferraro, F.; Formicola, A.; Fülop, Z.; Gervino, G.; Guglielmetti, A.; Gustavino, C.; Gyürky, G.; Junker, M.; Lemut, A.; Marta, M.; Mazzocchi, C.; Menegazzo, R.; Mossa, V.; Pantaleo, F.; Prati, P.; Rossi Alvarez, C.; Scott, D. A.; Somorjai, E.; Straniero, O.; Szücs, T.; Takacs, M.;
The correct prediction of the abundances of the light nuclides produced during the epoch of Big Bang Nucleosynthesis (BBN) is one of the main topics of modern cosmology. For many of the nuclear reactions that are relevant for this epoch, direct experimental cross section data are available, ushering the so-called “age of precision”. The present work addresses an exception to this current status: the 2 H( α,γ ) 6 Li reaction that controls 6 Li production in the Big Bang. Recent controversial observations of 6 Li in metal-poor stars have heightened the interest in understanding primordial 6 Li production. If confirmed, these observations would lead to a second cosmological lithium problem, in addition to the well-known 7 Li problem. In the present work, the direct experimental cross section data on 2 H( α,γ ) 6 Li in the BBN energy range are reported. The measurement has been performed deep underground at the LUNA (Laboratory for Underground Nuclear Astrophysics) 400 kV accelerator in the Laboratori Nazionali del Gran Sasso, Italy. The cross section has been directly measured at the energies of interest for Big Bang Nucleosynthesis for the first time, at Ecm= 80, 93, 120, and 133 keV. Based on the new data, the 2 H( α,γ ) 6 Li thermonuclear reaction rate has been derived. Our rate is even lower than previously reported, thus increasing the discrepancy between predicted Big Bang 6 Li abundance and the amount of primordial 6 Li inferred from observations.
Keywords: Big Bang Nucleosynthesis Nuclear Astrophysics Lithium problem

Publ.-Id: 25241 - Permalink


Use of specific metal binding of self-assembling S-layer proteins for metal bioremediation and recycling
Vogel, M.; Matys, S.; Lehmann, F.; Drobot, B.; Günther, T.; Pollmann, K.; Raff, J.;
Most bacteria and all archaea possess as outermost cell envelope so called surface-layers (S-layers). These S-layers are formed by self-assembling proteins having a number of interesting intrinsic properties, e.g. they mediate selective exchange of molecules and therefore function as molecular sieves. Furthermore, S-layers from bacterial isolates recovered from heavy metal contaminated environments have outstanding metal binding properties and are highly stable. Thus they selectively bind several metals with different affinity. For using S-layer proteins for metal bioremediation and recycling three aspects of the metal-interactions with S-layer proteins must be taken into account. First, S-layers possess different functionalities, e.g. carboxyl, phosphoryl groups, binding toxic metals and metalloids, like U and As, unspecifically depending on pH-value. Second, precious metals like Au and Pd are likewise unspecifically bound to functional groups, but presumably covalently, making the binding irreversible unless the S-layer protein is destroyed completely. Third, some metals are needed for native protein folding of the S-layer protein monomer, self-assembly, and the formation of highly-ordered lattices. These particular metals are specifically bound bivalent cations, e.g. Ca2+. Important is that these binding sites allow selective binding not only of Ca2+, but also of chemical-equal elements including the trivalent lanthanides (Eu3+, Tb3+), possessing comparable ionic radii. Thus the metal dependent binding behavior of the proteins not only contributes to the development of biohybrid materials for the separation, removal or recovery of strategic relevant metals regulated by pH and allowing a conceivably release, but also allows a biochemical and mechanistic understanding of the interaction of different metal ions with S-layer proteins .
Keywords: S-layer, bioremediation, recycling, self-assembly, metal
  • Poster
    22. International Biohydrometallurgy Symposium, 24.-27.09.2017, Freiberg, Deutschland
  • Contribution to proceedings
    22. International Biohydrometallurgy Symposium, 24.-27.09.2017, Freiberg, Deutschland
  • Open Access LogoSolid State Phenomena 262(2017), 389-393
    DOI: 10.4028/www.scientific.net/SSP.262.389

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Publ.-Id: 25240 - Permalink


The surface processes of Se(IV) on γ-alumina in the presence of carbonate. Evaluating competitive effects on the sorption behavior
Foerstendorf, H.ORC; Mayordomo, N.; Jordan, N.; Alonso, U.; Missana, T.; Schmeide, K.
The sorption and desorption processes of selenium(IV) onto γ-Al2O3 at different pH values and ionic strengths, as well as the impact of carbonate ions, have been studied by classical batch sorption experiments and in situ Attenuated Total Reflection Fourier-transform Infrared (ATR FT-IR) spectroscopy.

From recent X-ray absorption spectroscopic investigations the predominant surface complexes of Se(IV) on γ-alumina were identified as bidentate bridging complexes with AlO6 surface groups in the circumneutral pH range (pH 4 – 8) [1]. However, contributions of outer-sphere complexes were not completely ruled out. Thus, we performed batch sorption series and vibrational spectroscopic experiments at different ionic strengths to evaluate the fraction of prevailing outer-sphere complexation. It could be shown that Se(IV) sorption was independent of the ionic strength suggesting that outer-sphere complexation can be neglected under the prevailing conditions.

At more alkaline pH level, the sorption processes proceeded more reversibly than under acidic and neutral conditions, as it was derived from the IR spectroscopic experiments providing molecular information of the ongoing sorption and desorption processes in real time [2]. The enhanced release of the selenite from the alumina phase is due to modification of alumina surface properties at a higher pH level.

Carbonate ions were found to form outer-sphere monodentate complexes at the γ-Al2O3 surface, and hence, the respective sorption process was highly reversible. In the ternary sorption system, the Se(IV) adsorption onto alumina was found to be slightly reduced and an enhanced release of selenite subsequent to the sorption reaction was observed. A change of the speciation of selenite on the alumina surface in terms of structural alterations or different binding mechanism was not observed.

Our results strongly suggested that Se(IV) surface affinity towards γ-Al2O3 is higher than the one of carbonate ions. Nevertheless, the competing effect of carbonate ions might impact the migration of Se(IV) by reducing the number of available sorption sites on sorbing surfaces and by enhancing desorption processes. Consequently, this should be taken into account in predicting the environmental fate of Se(IV). Therefore, we performed Surface Complexation Model (SCM) calculations triggered by the spectroscopic findings and first results will be presented. The modelling of the surface speciation based on spectroscopic results has proven to be a strong tool to gain a sustainable description of the surface processes occurring in sorption systems relevant for the safety assessment of a future nuclear waste disposal site.

[1] E. J. Elzinga, et al., J. Colloid Interface Sci. 340, 153 (2009).
[2] H. Foerstendorf, et al., J. Colloid Interface Sci. 416, 133 (2014).
[3] M. J. Comarmond, et al., Environ. Sci. Technol. 50, 11610 (2016).
  • Poster
    Migration 2017 - 16th International Conference on the Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere, 10.-15.09.2017, Barcelona, Espania

Publ.-Id: 25239 - Permalink


Interactions between U(VI) doped CSH phases and high saline brines
Wolter, J.-M.; Schmeide, K.; Stumpf, T.;
Cementitious materials will be used for the geotechnical barrier of a deep geological repository where long-lived radioactive waste like used fuel rods will be stored [1]. Calcium silicate hydrate (CSH) phases, as main component of hardened cement paste, are known for their retention potential for radionuclides like U which is the main component of used fuel rods [2].

The formation water of North German clay stone formations is characterized by high ionic strengths [3], which potentially lead to a corrosion of concrete. Thus, with respect to long-term safety assessment of cement containing repositories chemical alteration processes at high saline conditions have to be studied. Therefore, the leaching of U(VI) doped CSH phases in high ionic strengths electrolyte solutions is studied in batch experiments in combination with spectroscopic methods.

The approach of this study is to get a molecular understanding of interactions between U(VI) doped CSH phases and high ionic strengths electrolyte solutions. For this, batch leaching experiments were performed in combination with spectroscopic methods.

The formation of CSH phases is confirmed by XRD and IR / Raman spectroscopy. The TRLFS spectra obtained for U(VI) doped CSH phases are comparable to those reported by Tits et al. [4]. Thus, an incorporation of U(VI) in the CSH phases is verified. The results of leaching experiments are exemplarily shown for Ca for the CSH phase with C/S ratio of 1.6 for in Figure. 1. In presence of NaCl and Na2SO4, Ca is released into the supernatant solution. This mainly can be attributed to a release of Ca from the interlayers of CSH phases. Simultaneously, the pH values of the supernatant solutions increase to values between 11.2 and 12, depending on the C/S ratio. In the presence of NaHCO3, the Ca concentration in solution is much lower due to precipitation of CaCO3. In this case, pH values between 11.4 and 10.1 are observed.

In the presence of NaCl and Na2SO4, the release of Si and U is minimal. In the presence of NaHCO3, however, the Si and U concentration in solution is increased. Since Si can only be released from the complex layers of CSH phases, the release of Si and simultaneously, the release of U can be related to a decomposition of the CSH phases in the presence of carbonate. Spectroscopic investigations also confirmed the decomposition of CSH phases and the release of U due to carbonate.
Keywords: CSH phases, uranium, North Germany, clay stone, cement, retention, leaching, PXRD, TRLFS, IR, RAMAN, saline, salt
  • Contribution to proceedings
    MIGRATION 2017, 10.-15.09.2017, Barcelona, España
    Interactions between U(VI) doped CSH phases and high saline brines
  • Contribution to proceedings
    ABC Salt V, 26.-28.03.2017, Ruidoso, New Mexico, USA
    Proceedings of ABC Salt V
  • Poster
    ABC Salt V Actinide and Brine Chemistry in a Salt Repository Workshop (V), 26.-28.03.2017, English, USA
  • Poster
    Migration 2017 16th International Conference on the Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere, 10.-15.09.2017, Barça, España

Publ.-Id: 25238 - Permalink


Comparative studie of two fungi and their molecular interactions with uranium(VI) and europium(III)
Wollenberg, A.; Günther, A.; Raff, J.; Stumpf, T.;
Radionuclides are widely used in industry, medicine and research. By their use, disposal, but also by accidental release radionuclides may reach the environment. There, their mobility and their behaviour is influenced by interactions with abiotic and biotic matter. As fungi are one of the most common microorganisms in nature, they have to be taken into consideration in particular. They play an important role for preservation of the soil structure and protect plants and symbiotic partners from intoxication [1, 2]. Furthermore, they interact with radionuclides in different ways leading to an immobilization and thus a reduced toxicity and a reduced migration through the soil [3, 4, 5]. The aim of this study was to investigate the binding and the uptake of uraniumVI and europiumIII, the latter as surrogate for trivalent actinides, by the two fungi Leucoagaricus naucinus and Schizophyllum commune.

First batch experiments showed the binding of UVI and EuIII by fungi depends on initial conditions. Both fungi showed a biphasic binding of the metals and interact different depending on pH value (see figure 1). In contrast, the fungi showed increasing sorption capacities with higher initial metal concentrations and lower initial biomass. Moreover, changes of the concentration of different ions in the solution before and after incubation were investigated. Furthermore, the UVI-binding of the fungi was examined with time-resolved laser-induced fluorescence spectroscopy (TRLFS). This studies were performed in dependence on metal concentration and pH value.
In General, obtained results provide first indication that the binding behavior of both fungi is due to different binding mechanisms.
  • Lecture (Conference)
    16th International Conference on the Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere, 10.-15.09.2017, Barcelona, España

Publ.-Id: 25237 - Permalink


Annual Report 2016 Institute of Resource Ecology
Stumpf, T.; Foerstendorf, H.ORC; Bok, F.; Richter, A.
The Institute of Resource Ecology (IRE) is one of the eight institutes of the Helmholtz-Zentrum Dresden – Rossendorf (HZDR). The research activities are mainly integrated into the program “Nuclear Waste Management, Safety and Radiation Research (NUSAFE)” of the Helmholtz Association (HGF) and focused on the topics “Safety of Nuclear Waste Disposal” and “Safety Research for Nuclear Reactors”...
  • Open Access LogoWissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-079 2017
    ISSN: 2191-8708

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Publ.-Id: 25236 - Permalink


Synthesis and structural characterization of mixed iron-uranium compounds with bidentate N-donor ligands
Schöne, S.ORC; Radoske, T.; März, J.; Stumpf, T.; Ikeda-Ohno, A.ORC
The reliable assessment of geochemical behavior of uranium (U) is one of the most significant issues for uranium mining sites and geological disposals of radioactive wastes. In addition to the major chemical parameters of groundwater, such as pH, ionic strength, co-existence of anionic species, etc., the oxidation state is one of the fundamental parameters which determine the geochemical behavior of uranium in aquatic environments. Under natural aquatic conditions, the redox chemistry of uranium is dominated either by uranyl(VI) (UO22+) mainly under aerobic conditions or by uranium(IV) (U4+) under anaerobic conditions [1]. The redox behavior of uranium is affected not only by solution conditions, but also by the co-existence of other redox-active ions, such as manganese (Mn) and iron (Fe) [2] which are ubiquitous in the actual aquatic environment. The interaction of U species with other redox species complicates the redox behavior of U, eventually influencing the interaction of U species with other organic ligands and inorganic anions [3,4]. Hence, the understanding of the chemical behavior of U in the presence of other redox active metals is indispensable for the reliable prediction of the geochemical behavior of U.
Based on this background, we performed a systematic study of the reactivity of U(IV) and -(VI) with Fe(II) and -(III), some of the major redox active species abundant in groundwater, in the presence of 2,2’-bipyridine (bipy) and 1,10-phenanthroline (phen) as representatives of naturally occurring N-donor organic ligands. Mixing U(IV)/U(VI) with Fe(II)/Fe(III) and bipy/phen in different solution conditions yielded a wide variety of single crystals of mixed Fe-U compounds, which were further characterized by single crystal / powder X-ray diffraction and other spectroscopic methods.
In the studied iron-uranium systems, the N-donor ligand (L) is always coordinating to Fe, forming [FeII(L)3]2+ or oxo-bridged [(FeIIIL2Cl)2(µ2-O)]2+ cationic units. Uranium is not directly interacting with the ligands, existing as the counter anionic unit of [UIVCl6]2- or [UVIO2Cl4]2- in the structures. This preferable coordination of the N-donor ligands towards iron is independent of the oxidation state of uranium. The interaction of Fe(III) (oxidant) with U(IV) (reductant) naturally resulted in the formation of Fe(II)-U(VI) mixed compounds. This redox reaction is not affected by the presence of the strong N-donor ligands.
These results provide us a molecular insight into the coordination and redox chemistry of the mixed iron-uranium systems in aqueous solutions, which has direct relevance to the geochemistry of uranium. The iron-uranium compounds characterized in this study are also rare examples of such mixed metal-uranium compounds with organic ligands.
  • Lecture (Conference)
    Migration 2017 - 16th International Conference on the Chemistry and Migration Behaviour of Actinides and Fission, 11.09.2017, Barcelona, Spanien

Publ.-Id: 25235 - Permalink


µTRLFS: Spatially-resolved sorption studies of Eu(III) on Äspö granite with time-resolved laser fluorescence spectroscopy
Zesewitz, K.; Schmidt, M.;
Finding a safe long-term repository for high-level nuclear waste is a highly relevant global issue. To that end, the interaction of radionuclides with mineral phases contained in possible host rocks and construction materials must be understood. On a time scale of up to a million years, especially the scenario of a water intrusion into the repository and thus dissolution of radionuclides has to be considered. To investigate the sorption behaviour of actinides (e.g. Cm(III) and U(VI)O22+) and lanthanides (e.g. Eu(III)), time-resolved laser fluorescence spectroscopy (TRLFS) is a widely used method, because of its trace concentration sensitivity and capability to distinguish multiple species in complex systems. On the one hand this method gives the spectral information of the emitted fluorescence light, which allows determining the symmetry and the grade of complexation of the sorbed Ln/An. On the other hand the lifetimes of the excited electronic states provide information about the surrounding quenchers, mainly water. Typically, TRLFS investigations will focus on the interaction of an actinide with one relevant mineral phase. For a real rock formation, e.g. granite, sorption will however be a competitive process involving multiple mineral phases at the same time.
In this study a new method called µTRLFS is introduced, which will add a spatial dimension to TRLFS. By doing so, it is possible to separate the multi-phase system into discrete single-phase systems and therefore to make a step beyond model systems by investigating, for example whole natural granite rock with TRLFS. Because of its advantageous fluorescence properties we use europium as an analogue for the trivalent actinides americium and curium. Spatially resolved sorption experiments with Eu(III) on granite samples from the underground laboratory in Äspö, Sweden are presented. These samples are excited by a focused laser beam at a wavelength of 394 nm, and scanned through the laser’s focal point by an XYZ-stage with a resolution of approximately 50 µm. Through this approach it becomes possible to characterize Eu(III) sorption on single grains of the complex material by mapping fluorescence intensity, F2/F1-band ratios, as well as fluorescence lifetimes.
A combination of Raman-microscopy and energy dispersive X-ray spectroscopy (EDX) is used to reveal the mineral phase composition in each point of measurement which can then be correlated to the µTRLFS maps. On top of that EDX provides impurity distributions of e.g. iron or manganese as additional quenchers. By doing so, µTRLFS mapping of sorption capacity, complexation strength and surrounding quenchers can be correlated to phase distribution mappings and thus provide information about the sorption behaviour of each phase within the complete multi-phase system. The µTRLFS data will then be directly compared to single phase TRLFS data of the granite components quartz, feldspar and mica. For verification, the Eu(III) distribution obtained from µTRLFS data will be matched to spatially-resolved X-ray absorption spectroscopy (µXAS).
Keywords: µTRLFS, TRLFS, µXAS, granite, Raman, EDX, sorption, europium
  • Poster
    16th International Conference on the Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere, 10.-15.09.2017, Barcelona, Spanien

Publ.-Id: 25234 - Permalink


Verbundprojekt WASA-BOSS: Weiterentwicklung und Anwendung von Severe Accident Codes – Bewertung und Optimierung von Störfallmaßnahmen; Teilprojekt B: Druckwasserreaktor-Störfallanalysen unter Verwendung des Severe-Accident Code ATHLET-CD – Abschlussbericht
Jobst, M.; Kliem, S.; Kozmenkov, Y.; Wilhelm, P.;
Innerhalb des Vorhabens wurde ein ATHLET-CD-Eingabedatensatz für einen generischen deutschen DWR vom Typ KONVOI entwickelt. Das ATHLET-CD-Modell wurde für die Simulation schwerer Störfälle aus den Störfallkategorien Station Blackout (SBO) und Kühlmittelverluststörfällen mit kleinen Lecks (SBLOCA) eingesetzt. Dabei ist die vollständige Störfalltransiente für den Zeitbereich zwischen dem einleitenden Ereignis bis zum Versagen des Reaktordruckbehälters (RDB) abgedeckt und alle wesentli-chen Phänomene schwerer Störfällen werden abgebildet: Beginn der Kernaufheizung, Spaltproduktfrei-setzung, Aufschmelzen von Brennstoff- und Absorbermaterialien, Oxidationsprozesse mit Freisetzung von Wasserstoff, Verlagerung von geschmolzenem Material, Verlagerung in das untere Plenum, Schä-digung und Versagen des RDB. Das Modell wurde für die Analyse möglicher präventiver und mitigativer Notfallmaßnahmen für SBO und SBLOCA angewandt. Dafür wurden die Notfallmaßnahmen primärseitige Druckentlastung (PDE), primärseitiges Einspeisen mit mobilen Pumpensystemen sowie für SBLOCA das verzögerte Einspeisen der kaltseitigen Druckspeicher untersucht und die Eigenschaften und Einleitekriterien der Maßnahmen variiert. Es wurden die Zeitverläufe der Unfallszenarien analysiert und die verbleibenden Zeitspannen für die Einleitung zusätzlicher Maßnahmen ermittelt. Für ein SBO-Szenario mit PDE wurde für die Frühphase der Transiente (bis zum Beginn der Kernschmelze) eine Unsicherheits- und Sensititvitätsanalyse durchgeführt. Zusätzlich wurde für ein SBLOCA-Szenario ein Code-zu-Code-Vergleich zwischen ATHLET-CD und dem Störfallcode MELCOR erarbeitet.
Keywords: Druckwasserreaktor, Schwere Störfälle, Notfallmaßnahmen, ATHLET-CD-Simulation, Pressurized Water Reactor, Severe accidents, Accident management measures, ATHLET-CD simulations
  • Open Access LogoWissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-080 2017

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Publ.-Id: 25233 - Permalink


Retention Of An(III)/Ln(III) By Calcite: Influence Of Mineral Formation On Contaminant Speciation
Schmidt, M.; Hellebrandt, S. E.; Johnstone, E. V.; Hofmann, S.; Barkleit, A.; Jordan, N.; Cherkouk, A.; Stumpf, T.;
Calcite has been intensively studied for its potential to structurally incorporate trivalent actinides and lanthanides. As calcite is both a ubiquitous mineral in many host rock formations, and an important weathering product of cementitious phases it may occur in a nuclear waste disposal site as both, a primary and a secondary phase. In addition, in the far-field of such a disposal site calcite can be formed by microbiota. In order to understand if the origin of the mineral will impact its capacity to incorporate trivalent cations, we will present and compare the speciation of Eu(III) and Cm(III) in calcite formed inorganically via co-precipitation[1] and co-precipitation/phase transformation[2] with calcite formed in a microbially-induced precipitation reaction[3] and calcite contacted with Eu(III) close to equilibrium.[4]
Investigations using site-selective TRLFS reveal that the speciation of M(III) co-precipitated with calcite formed inorganically consists of three species, labelled A, B, and C, respectively, independent of the formation mechanism. The species have been characterized as two incorporation species, differing in the degree of lattice distortion, and a sorption species in contact with the solution.[1] Contrary to this behaviour the speciation of Eu(III) in both, calcite formed in a microbially-induced reaction, and after reaction with calcite close to equilibrium conditions comes to be dominated by a different incorporation species, labelled γ.
Species γ is also Eu(III) incorporated into the crystal bulk, but shows a lower symmetry than observed previously, and does not match with any of the previous species. It can be shown that the rate of formation of γ depends heavily on the recrystallization rate of the calcite used in the reaction, and that its formation is accompanied by several other species, some of which had been identified previously.
The formation of species γ as the main mode of interaction in the microbial process is particularly interesting as the reaction proceeds via vaterite, the same metastable polymorph used in a previous abiotic study. The speciation in the intermediate vaterite phases does not differ, yet the speciation in the calcite product shows little similarity.
In summary, the results highlight the importance of molecular level understanding for accurately describing the interaction of dissolved cations with surrounding mineral phases.


*Present address: Department of Materials Science and Engineering, The University of Sheffield, Sheffield, United Kingdom, S10 2TN.
[1] Schmidt, M., T. Stumpf, M. Marques Fernandes, et al., Angew. Chem. Int. Ed., 47, 5846 (2008).
[2] Schmidt, M., T. Stumpf, C. Walther, et al., J. Colloid Int. Sci., 351, 50 (2010).
[3] Johnstone, E.V., S. Hofmann, A. Cherkouk, et al., Env. Sci. Tech., 50, 12411 (2016).
[4] Hellebrandt, S.E., S. Hofmann, N. Jordan, et al., Sci. Rep., 6, 33137 (2016).

Acknowledgments. This study is supported by the Helmholtz Gemeinschaft Deutscher Forschungszentren by funding the Helmholtz Young Investigator Group “Structures and reactivity at the aqueous/mineral interface” (VH-NG-942).
Keywords: Calcite, TRLFS, actinides, europium, curium, co-precipitation, solid solutions
  • Lecture (Conference)
    16th International Conference on the Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere, 10.-15.09.2017, Barcelona, Spanien
  • Poster
    16th International Conference on the Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere, 10.-15.09.2017, Barcelona, Spanien

Publ.-Id: 25232 - Permalink


Probing ultra-fast processes with high dynamic range at 4th-generation light sources: arrival time and intensity binning at unprecedented repetition rates
Kovalev, S.; Green, B.; Golz, T.; Maehrlein, S.; Stojanovic, N.; Fisher, A. S.; Kampfrath, T.; Gensch, M.;
Understanding dynamics on ultrafast timescales enables unique and new insights into important processes in the materials and life sciences. In this respect, the fundamental pump-probe approach based on ultra-short photon pulses aims at the creation of stroboscopic movies. Performing such experiments at one of the many recently established accelerator-based 4th-generation light sources such as free-electron lasers (FELs) or superradiant THz sources allows an enormous widening of the accessible parameter space for the excitation and/or probing light pulses. Compared to table-top devices, critical issues of this type of experiment are fluctuations of the timing between the accelerator and external laser systems and intensity instabilities of the accelerator-based photon sources. Existing solutions have so far been only demonstrated at low repetition rates and/or achieved a limited dynamic range in comparison to table-top experiments, while the 4th generation of accelerator-based light sources is based on superconducting radio-frequency (SRF) technology which enables operation at MHz or even GHz repetition rates. In this article, we present the successful demonstration of ultra-fast accelerator-laser pump-probe experiments performed at an unprecedentedly high repetition rate in the few-hundred-kHz regime and with a currently achievable optimal time resolution of 13 femtoseconds (fs) (rms). Our scheme, based on the pulse-resolved detection of multiple beam parameters relevant for the experiment, allows us to achieve an excellent sensitivity in real-world ultra-fast experiments, as demonstrated for the example of THz-field-driven coherent spin precession.
Keywords: ultra-fast, high field THz

Publ.-Id: 25231 - Permalink


Produktion und Reinigung von n.c.a. 89Zr am Leipziger Zyklotron für Extraktionsstudien mit Calix[4]arenen
Mansel, A.; Franke, K.;
Zirkonium ist eine der Hauptverunreinigungen in Lanthanidenerzen. Um effiziente Abtrennungsverfahren von vierwertigem Zirkonium von den dreiwertigen Lanthaniden mit Hilfe der Flüssig-Flüssig-Extraktion mit Calixarenen zu entwickeln, wurde die Radiotracertechnik eingesetzt [89Zr; T1/2 = 78,4 h; Eγ = 909 keV; 99 %]. Die Produktion dieses Radionuklides wurde am Leipziger Zyklotron CYCLONE 18/9® durch die Kernreaktion 89Y(p,n)89Zr realisiert. Eine Yttriumfolie (natürliche Isotopenzusammensetzung 100 % 89Y; 80 mg) wurde mit Protonen der Energie 14 MeV bei einem Strom von 22 µA für eine Stunde bestrahlt. Das bestrahlte Target wurde für eine Stunde zum Abklingen des kurzlebigen Radionuklides 89mZr (T1/2 = 4,2 min) aufbewahrt und anschließend in konzentrierter HNO3 aufgelöst. Nach dem Eindampfen wurde der Rückstand mit 9 M HNO3 aufgenommen. Die Trennung von 89Zr vom Targetmaterial Yttrium erfolgte mit dem Ionenaustauscher UTEVA-SPEC®, wobei Y3+ mit 9 M von dem Säulenmaterial eluiert wird. 89Zr4+ wurde vom Ionentauscher mit Hilfe von 0,1 M Oxalsäure gewaschen. Der Oxalsäurekomplex wurde durch Erhitzen mit konzentrierter H2SO4 zersetzt und das n.c.a. 89Zr wurde in 1 M H2SO4 aufgenommen. Die radiochemische Ausbeute betrug (101 ± 8) %. Die Aktivität betrug fünf Stunden nach Bestrahlungsende ~ 400 MBq und die Nachweisgrenze wurde zu 7 fM (0,6 pg/L) für n.c.a. 89Zr ermittelt.
Die Flüssig-Flüssig-Extraktion erfolgte in einem Calixaren/Chloroform-System, wobei in saurer Lösung zwischen pH 1 und 5 gearbeitet wurde. Das Calixaren weist sowohl eine Phosphonatester- als auch eine Carboxylsäurefunktion auf. Die wässrige Phase (~ 5 MBq/L 89Zr und 10 µM nicht-radioaktives Zr4+) wurde mit dem zehnfachen Überschuß an Calixaren in Chloroform eine Stunde geschüttelt. Nach der Phasenseparation wurden beide Phasen mittels γ-Spektrometrie vermessen. Eine maximale Extraktionsausbeute von 95 % wurde für Zirkonium bei pH 4 ermittelt. Somit ist die Trennung von Zr und Eu realisierbar, da Eu bei pH 8 zu 98 % extrahiert wurde, bei pH 4 nur zu < 5 %.
Keywords: Zirkonium; Zyklotron; Radionuklidproduktion; Separation; Calixaren; Extraktion; Lanthanide
  • Poster
    GDCh - Wissenschaftsforum - Jahrestagung Fachgruppe Nuklearchemie, 10.-14.09.2017, Berlin, Deutschland

Publ.-Id: 25230 - Permalink


Effect of pH on the mobility of the herbicide MCPA in an artificial soil matrix: Reactive transport modelling on the basis of 3D flow patterns visualized by Positron Emission Tomography
Lippold, H.; Karimzadeh, L.; Kulenkampff, J.; Stuhlfauth, C.; Lippmann-Pipke, J.;
Adsorption and transport of the herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) in a sand-goethite matrix were investigated as a function of pH. Compared to adsorbed amounts reported for freshly prepared goethite, adsorption onto the commercial product used in this study was found to be considerably lower. Under acidic conditions, transport of MCPA was, however, significantly retarded referring to [3H]H2O as a conservative tracer. Interaction as a function of pH was geochemically modelled using the charge distribution multisite complexation (CD-MUSIC) approach. Based on this calibrated surface complexation model, breakthrough curves were calculated according to the 1D advection-dispersion-reaction equation. Retardation was slightly underestimated at low pH.
As a new approach, this study demonstrates quantitatively that discrepancies between batch and column systems can be caused by peripheral flow, i.e., not necessarily by non-equilibrium conditions, which are commonly taken into account. By means of Positron Emission Tomography (PET) using [18F]F as a radiotracer, flow patterns in the sand-goethite matrix were visualized in 3D. A pseudo-3D flow and transport model was aligned to the images. The observed flow profile was successfully simulated by assuming a peripheral zone with increased permeability and porosity. With this flow model, reactive transport of MCPA was predicted more precisely compared to the 1D calculations with the same parameter values.
  • Poster
    Jahrestagung der GDCh-Fachgruppe Nuklearchemie, 12.-13.09.2017, Berlin, Deutschland

Publ.-Id: 25229 - Permalink


Novel Valdecoxib Derivates by Ruthenium-catalyzed 1,3-Dipolar Cycloaddition of Nitrile Oxides with Alkynes - Synthesis and COX-2 Inhibition Affinity.
Roscales, S.; Bechmann, N.; Weiss, D. H.; Köckerling, M.; Pietzsch, J.; Kniess, T.;
Novel valdecoxib-based cyclooxygenase-2 inhibitors were synthesized in one step via 1,3-dipolar cycloaddition of nitrile oxides with a series of eleven, partly novel aryl alkynes. Application of Ru(II)-catalysis leads preferably to the formation of the 3,4-diaryl-substituted isoxazoles, while under thermal heating with base the 3,5-diaryl substitution pattern is favoured. The new the 3,4-diaryl-substituted isoxazoles possessing a small substituent (H and Me) displayed high COX-2 inhibition affinity (IC50=0.042–0.073 µM) and excellent selectivity (COX-2 SI > 2000). In contrast, the 3,5-diaryl-substituted compounds displayed almost no COX activity. The application of fluoro-substituted nitrile oxides resulted in enhanced COX-2 affinity, making these compounds together with the feasible one step reaction promising candidates for the development of fluorine-18 labelled radiotracers for positron emission tomography.

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Publ.-Id: 25228 - Permalink


ROBL-II: A dedicated actinide beamline for X-ray spectroscopy and scattering techniques
Scheinost, A. C.; Kvashnina, K.; Hennig, C.; Exner, J.; Rossberg, A.; Schmidt, M.; Stumpf, T.;
The Rossendorf Beamline (ROBL) operates since 1999 as a single-branch, double-experiment, multi-purpose X-ray beamline for radiochemistry and materials sciences. After 13 years of successful operation, the optical components of ROBL were replaced by state-of-the-art equipment, including a LN2-cooled double-crystal/double-multilayer monochromator, and a 1.2-m double-toroid focusing mirror with Pt and Rh coatings and 1.0 µrad slope errors. Since 2015, both experimental stations belong to the Institute of Resource Ecology at HZDR and are dedicated to study actinides. In 2016, a major upgrade program started to provide additional or largely improved techniques:
(1) A five-crystal Johann-type spectrometer with variable Rowland circle of 0.5 to 1 m to measure high-energy-resolution fluorescence detection XANES, XES and RIXS [1].
(2) A new 6-circle diffractometer for powder diffraction, crystal truncation rod (CTR) and resonant anomalous X-ray reflectivity (RAXR) measurements.
(3) A large 2D detector will further support the structure analysis of materials (PXRD, single crystal diffraction, PDF analysis).
(4) A new Ge-based energy dispersive detection system with ultrafast electronics to obtain detection limits for bulk XAS near or even below 1 ppm, and automated sample feeders for room temperature and cryogenic (10 K) conditions to enable a high sample throughput.
All experiments will be available from 2020 on in a control area comprising two hutches connected by a common lock room, which allows an easy exchange of radioactive samples (alpha emitters with total activity below 185 MBq) between four experimental stations.
Furthermore, ROBL-II will significantly benefit from the new electron storage ring of the ESRF installed in 2019/2020. ROBL-II’s new source, a short bending magnet, will provide a photon flux of 1013 ph/s across a wide energy range (3 to 35 keV). The much lower vertical divergence will allow us to obtain a spot size of 30 x 70 µm2 with the toroid mirror, thereby raising the photon density by an order of magnitude as compared to the current storage ring.
The complete experimental portfolio of ROBL-II will be available to users from 2020 on, for more than 200 (24-h) days per year, establishing the key role of ROBL-II for synchrotron-based actinide chemistry, and additionally providing beamtime for fundamental chemistry, catalysis, materials and earth sciences.

[1] K. O. Kvashnina and A. C. Scheinost, Journal of Synchrotron Radiation 2016, 23, 836-841.
Keywords: synchrotron actinides XAFS XES XRD CTR RAXR
  • Invited lecture (Conferences)
    AnXAS 2017: 8th Workshop on Speciation, Techniques, and Facilities for Radioactive Materials at Synchrotron Light Sources, 10.-13.04.2017, Oxford, United Kingdom
  • Lecture (Conference)
    ATAS Workshop, 06.-09.11.2018, Nice, France

Publ.-Id: 25227 - Permalink


Glutamine metabolism as a potential target for prostate cancer radiosensitization
Tyutyunnykova, A.; Peitzsch, C.; Telegeev, G.; Dubrovska, A.;
Tumor relapse associated with increased chemo- and radioresistance is a major problem for prostate cancer patients. Our previous findings suggest that altered amino acid (in particular, glutamine) metabolism can be associated with radioresistance of prostate cancer. The main aim of our project is to investigate the role of glutamine metabolism in the development of prostate cancer radioresistance and to find novel biomarkers to predict radiation treatment outcome. We used isogenic radioresistant cell lines developed from standard prostate cancer cell lines DU145, PC3, 22RV1 and LNCaP and analyzed the following parameters: the differential expression of genes involved in glutamine metabolism, cells’ tumorigenicity, metabolites of Krebs cycle, the amount of reactive oxygen species (ROS) and glutathione in cells, radioresistance of cells and DNA damage after irradiation.
Our findings suggest that glutamine metabolism contributes to prostate tumor cell proliferation, stem cell marker expression, tumorigenicity, oxidative stress, radioresistance and epigenetic changes. The combination of irradiation with inhibition of glutamine metabolism may increase the cytotoxic effects of irradiation in prostate tumor cells. Expression of the proteins involved in glutamine metabolism can be used to predict clinical outcome of prostate cancer patients. The intracellular mechanisms of the differential tumor cell sensitivity to glutamine supplementation are in the focus of ongoing study.
  • Contribution to proceedings
    Keystone symposia: Tumor Metabolism: Mechanisms and Targets (X3), 05.-09.03.2017, Whistler, Canada

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Publ.-Id: 25226 - Permalink


Coordination polymers of tetravalent uranium and neptunium with aromatic polycarboxylate ligands
Martin, N. P.; März, J.; Volkringer, C.; Henry, N.; Hennig, C.ORC; Ikeda-Ohno, A.ORC; Loiseau, T.ORC
Coordination polymers are organic-inorganic complexes built up from the association of metallic centers with organic (e.g. O- or N-donor) ligands. In the particular case of actinides (An), precedent studies have reported mainly the synthesis of solid networks bearing U(VI) or Th(IV), while trans-uranium elements have been much less studied due to their high radiotoxicity and limited amount of the material source. Among the possible oxidation states of An, the tetravalent state has been investigated most actively and large polyoxo clusters have been isolated for U or Pu. In contrast, there are very few data concerning Np(IV) compounds. In 2012, Takao et al. reported the presence of a hexanuclear cluster of Np(IV) in an aqueous solution, which is the only polyoxo cluster reported for Np(IV) thus far. The knowledge of the formation of such polynuclear An(IV) species could be of significant importance for the fate of An in contaminated soils containing O-donor ligands, such as humic acids, or other organic pollutants (e.g. phthalates).
In the present work, we studied the crystallization of U(IV) and Np(IV) with various aromatic polycarboxylate ligands in different solvents and analysed their crystal structures. In an aqueous medium, an infinite chain of An2O2(H2O)2(1,2-bdc)2 (An = U, Np) were isolated in the presence of phthalate. This compound crystallizes as aggregates of green or orange plates for U and Np, respectively. With mellitic acid the oxidation of Np(IV) to Np(V) was observed and led to large green plates. Single-crystal XRD analysis revealed layers of {NpO7H2O0-2} units linked to each other via trans-dioxo neptunyl bonds. Similar coordination environments have been observed in other neptunium(V) compounds. To the contrary, the same synthesis procedure with U(IV) led to an U(IV)-based compound: U2(OH)2(H2O)2(mel), in which two uranium atoms are linked by hydroxo groups; mellitate ligands stabilize and connect these dinuclear units.
The use of other solvents allowed the crystallization of large polynuclear discrete Np(IV) clusters. For example, using DMF, the hexanuclear moiety of [Np6O4(OH)4] has been obtained with different dicarboxylic ligands and is the basic building unit to form an open-framework structure. The corresponding structure reveals for the first time the isolation of the hexanuclear cluster An6O8 with Np(IV). These clusters are linked by the ligand creating tetrahedral and octahedral voids in the structure.
Keywords: actinides, uranium, neptunium, tetravalent, single-crystal X-ray diffraction, carboxylate, polymer, cluster
  • Lecture (Conference)
    16th International Conference on the Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere (Migration 2017), 10.-15.09.2017, Barcelona, Spain

Publ.-Id: 25225 - Permalink


Thermal Anemometry Grid Sensor
Arlit, M.; Schleicher, E.; Hampel, U.;
A novel thermal anemometry grid sensor was developed for the simultaneous measurement of cross-sectional temperature and axial velocity distribution in a fluid flow. The sensor consists of a set of temperature resistors arranged in a regular grid. Each temperature resistor allows the simultaneous measurement of fluid temperature via electrical resistance and of flow velocity via constant voltage thermal anemometry. Cross-sectional measurement is enabled by applying a special multiplexing-excitation scheme. In this paper we report on the design and characterization of a prototypical sensor.
Keywords: Temperature measurement, thermal anemometry, grid sensor

Publ.-Id: 25224 - Permalink


Thermofluiddynamische und konstruktive Auslegung sowie Aufbau und Inbetriebnahme eines Strömungskanals zur Untersuchung des konvektiven Wärmeübergangs an innovativen Rippenrohren
Stasch, P.;
Im Rahmen dieser Diplomarbeit wird die thermofluiddynamische und konstruktive Auslegung eines Strömungskanals zur Untersuchung von innovativen Rippenrohrdesigns beschrieben. Die Kernmotivation stellt dabei die Verbesserung des luftseitigen Wärmeübergangs an berippten Rohren dar. Dieser ist der limitierende Faktor für die Leistungsfähigkeit von luftgekühlten Rippenrohrwärmeübertragern. Der luftseitige Wärmeübergang ist von mehreren Faktoren, wie dem Rippendesign, dem Rippenabstand oder dem Strömungsfeld zwischen den Rippen abhängig. Demzufolge ist der Einfluss von geometrischen Parametern auf Wärmeübergangs- und Druckverlustcharakteristika bereits seit Jahren Untersuchungsgegenstand zahlreicher Studien. Die vorgelegte Arbeit gibt einen Überblick über die bisher untersuchten Geometrieparameter und deren Einfluss auf den Wärmeübergang. Wie aus der Literaturrecherche hervorgeht, bleibt die Untersuchung des Einflusses der radialen Wärmeleitung innerhalb einer Rippe, des Rippenwirkungsgrades oder auch des Anströmwinkels bis dato weitestgehend unberücksichtigt. Diese Arbeit beschreibt die Auslegung und Konstruktion eines Strömungskanals zur experimentellen Untersuchung dieser Einflussgrößen. Zur Bestimmung der Abmessungen des Strömungskanals wurde ein Rippenrohr unter festgelegten Randbedingungen ausgelegt, um einen Rippenwirkungsgrad von 30% zu erreichen. Möglichst große Rippenhöhen ermöglichen eine Untersuchung der radialen Wärmeleitung innerhalb der Rippen. Ein Wärmestrom wird mithilfe elektrischer Heizstäbe im Inneren des Rohres erzeugt.Auf der Grundlage der Dimensionen desRippenrohres wurde die Querschnittsfläche des Strömungskanals festgelegt. Zur Gewährleistung eines homogenen Strömungsprofils am Eintritt in die Testsektion wurden geeignete Einbauten zur Strömungsgleichrichtung ausgewählt. Um den Einfluss des Anströmwinkels untersuchen zu können, bietet der Strömungskanal zudem die Möglichkeit Rippenrohre in unterschiedlichen Neigungswinkeln zu installieren. Des Weiteren wurde geeignete Messtechnik im Strömungskanal installiert, mit der es möglich ist, die zur Bestimmung des Wärmeübergangs notwendigen physikalischen Größen zu erfassen. Im letzten Abschnitt der Diplomarbeit wurden die durch die Messgeräte bedingten Unsicherheiten bei der Bestimmung der charakteristischen Größen zur Beschreibung des konvektiven Wärmeübergangs ermittelt. Der Strömungskanal bietet die Möglichkeit, Rippenrohre in einem homogenen Strömungsfeld unter verschiedenen Anströmwinkeln experimentell untersuchen zu können. Der Bau des Strömungskanals leistet einen Beitrag den luftseitigen Wärmeübergang an Rippenrohren besser verstehen zu können, um so die Effizienz luftgekühlter Rippenrohrwärmeübertrager mithilfe innovativer Rippendesigns weiter zu verbessern.
  • Diploma thesis
    TU Dresden, 2017
    Mentor: Sebastian Unger, Matthias Beyer
    150 Seiten

Publ.-Id: 25223 - Permalink


A novel nanobody-based target module for retargeting of T lymphocytes to EGFR-expressing cancer cells via the modular UniCAR platform
Albert, S.; Arndt, C.; Feldmann, A.; Bergmann, R.; Bachmann, D.; Koristka, S.; Ludwig, F.; Ziller-Walter, P.; Kegler, A.; Gärtner, S.; Schmitz, M.; Ehninger, A.; Cartellieri, M.; Ehninger, G.; Pietzsch, H.-J.; Pietzsch, J.; Steinbach, J.; Bachmann, M.;
Recent treatments of leukemias with chimeric antigen receptor (CAR)-expressing T cells underline their impressive therapeutic potential. However, once adoptively transferred into patients, there is little scope left to shut them down after elimination of tumor cells or in case adverse side effects occur. This becomes of special relevance if they are directed against commonly expressed tumor associated antigens (TAAs) such as receptors of the ErbB family. To overcome this limitation, we recently established a modular CAR platform technology termed UniCAR. UniCARs are not directed against TAAs but instead against a unique peptide epitope on engineered recombinant targeting modules (TMs) which guide them to the target. In the absence of a TM UniCAR T cells are inactive. Thus an interruption of any UniCAR activity requires an elimination of unbound TM and the TM complexed with UniCAR T cells. Elimination of the latter one requires a disassembly of the UniCAR-TM complexes. Here we describe a first nanobody (nb)-based TM directed against EGFR. The novel TM efficiently retargets UniCAR T cells to EGFR positive tumors and mediates highly efficient target-specific and target-dependent tumor cell lysis both in vitro and in vivo. After radiolabeling of the novel TM with 64Cu and 68Ga we analyzed its biodistribution and clearance as well as the stability of the UniCAR-TM complexes. As expected unbound TM is rapidly eliminated while the elimination of the TM complexed with UniCAR T cells is delayed. Nonetheless, we show that UniCAR-TM complexes dissociates in vitro and in vivo in a concentration-dependent manner in line with the concept of a repeated stop and go retargeting of tumor cells via the UniCAR technology.
Keywords: CAR, EGFR, Retargeting, T cell, T cell therapy

Publ.-Id: 25222 - Permalink


CFD-Simulation of boiling in a heated pipe including flow pattern transitions using the GENTOP concept
Höhne, T.; Krepper, E.; Lucas, D.; Montoya, G.;
Boiling flow inside a wall heated vertical pipe is simulated by a multi-field CFD approach. Sub-cooled water enters the pipe from the lower end and heats up first in the near wall region leading to the generation of small bubbles. Further along the pipe larger and larger bubbles are generated by coalescence and evaporation. This leads to transitions of the two-phase flow patterns from bubbly to churn-turbulent and annular flow. The CFD simulation bases on the recently developed GEneralized TwO Phase flow (GENTOP) concept. It is a multi-field model using the Euler-Euler approach. It allows the consideration of different local flow morphologies including transitions between them. Small steam bubbles are handled as dispersed phases while the interface of large gas structures is statistically resolved. The paper presents the extension of the GENTOP model for phase transfer and discusses the sub-models used. Finally the above mentioned boiling pipe is considered as demonstration case.
Keywords: CFD, GENTOP, multiphase flow, AIAD, boiling
  • Contribution to proceedings
    The 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-17), 03.-08.09.2017, Xian, China
  • Lecture (Conference)
    The 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-17), 03.-08.09.2017, Xian, China
  • Nuclear Engineering and Design 322(2017), 165-176
    DOI: 10.1016/j.nucengdes.2017.06.047

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  • Secondary publication expected

Publ.-Id: 25221 - Permalink


Recent Developments in CFD Modeling of Multiphase Flows in Energy related Industrial Applications
Höhne, T.;
Two-phase flows occur in many industrial processes. Reliable predictions on flow characteristics are necessary for the design, process optimization and safety analysis of related apparatuses and processes. Experimental investigations are expensive and in most cases not transferable to modified geometries or different scales and flow conditions. For this reason there is a clear requirement for numerical tools. Due to the 3D nature of flows and the importance of turbulence in most cases this means a strong need for reliable 3D CFD-tools rather than 1D system codes or simplified correlations. The general aim is to provide simulation tools for the design, optimization and safety analyses of medium and large scale applications in which multiphase flows are involved. Such tools can contribute to improve the efficient use of energy and resources (e.g. in chemical engineering and oil industries) and to guarantee the safe operation (especially nuclear safety) – provided that they are predictive. Since large scale applications are considered such as chemical reactors or components of the cooling system of a nuclear power plant the Euler-Euler two- or multi fluid model is the base for the development. Presently the predictive capabilities for basic hydrodynamics are restricted due to limitations of the closure models. For this reason one focus of our multiphase flow research is the improvement of the closures first for adiabatic flow modelling but also phase transfer, chemical reactions etc. have to be considered. A second focus is to establish modelling frameworks as iMUSIG, AIAD and GENTOP to allow a proper consideration of the local physical phenomena. These activities will help to improve the CFD code capabilities in energy related industrial applications.
Keywords: CFD, iMUSIG, AIAD, GENTOP, multiphase flow
  • Contribution to proceedings
    The 7th International ENERGY Conference & Workshop - REMOO, 10.-12.05.2017, Venedig, Italien
  • Invited lecture (Conferences)
    The 7th International ENERGY Conference & Workshop - REMOO, 10.-12.05.2017, Venedig, Italien

Publ.-Id: 25220 - Permalink


CFD-simulation of boiling in a heated pipe including flow pattern transitions using a multi-field concept
Höhne, T.; Krepper, E.; Lucas, D.; Montoya, G.;
Boiling flow inside a wall heated vertical pipe is simulated by a multi-field CFD approach. Sub-cooled water enters the pipe from the lower end and heats up first in the near wall region leading to the generation of small bubbles. Further along the pipe larger and larger bubbles are generated by coalescence and evaporation. This leads to transitions of the two-phase flow patterns from bubbly to churn-turbulent and annular flow. The CFD simulation bases on the recently developed GEneralized TwO Phase flow (GENTOP) concept. It is a multi-field model using the Euler-Euler approach. It allows the consideration of different local flow morphologies including transitions between them. Small steam bubbles are handled as dispersed phases while the interface of large gas structures is statistically resolved. The paper presents the extension of the GENTOP model for phase transfer and discusses the sub-models used. Finally the above mentioned boiling pipe is considered as demonstration case.
Keywords: multi-phase, boiling, GENTOP, multi-scale, CFD
  • Contribution to proceedings
    12th International Conference on CFD in Oil & Gas, Metallurgical and Process Industries, 30.05.-01.06.2017, Trondheim, Norwegen
  • Lecture (Conference)
    12th International Conference on CFD in Oil & Gas, Metallurgical and Process Industries, 30.05.-01.06.2017, Trondheim, Norwegen

Publ.-Id: 25219 - Permalink


Application of computational fluid dynamics (CFD) codes for nuclear power plant design
Krause, M.; Smith, B.; Höhne, T.;
The nuclear industry recognises that CFD codes have reached the desired level of maturity (at least for single-phase applications) to be used as part of the NPP design process, and it is the objective of this IAEA Coordinated Research Project (CRP) to assess their current capabilities in this regard, and contribute to the technology advance in respect to their verification and validation. Currently, this CRP is ongoing, with participation from 14 member states to address the issue, following a three-pronged approach:
1. Preparation of a Summary Document to put on record the use of CFD in the nuclear reactor design process;
2. Development of (four) detailed, NPP design-oriented CFD benchmark exercises; and
3. Documentation of participants’ CFD simulations of these benchmarks, including the use of best-practice recommendations.
This paper describes the structure of the CRP, the Summary Document, and two of the benchmarks launched. Both benchmarks are related to safety issues in PWRs and are based on completed, but not yet published, measured data from ROCOM facility tests: one related to pressurized thermal shock (PTS) and the other to boron dilution.
Keywords: IAEA, ROCOM, CFD, PTS, CRP, NPP
  • Contribution to proceedings
    IAEA International Conference on Topical Issues in Nuclear Installation Safety, 06.-09.06.2017, Wien, Österreich
  • Lecture (Conference)
    IAEA International Conference on Topical Issues in Nuclear Installation Safety, 06.-09.06.2017, Wien, Österreich

Publ.-Id: 25218 - Permalink


A combined EXAFS spectroscopic and quantum chemical study on the complex formation of Americium(III) with formate
Froehlich, D. R.; Kremeleva, A.; Rossberg, A.; Skerencak-Frech, A.; Koke, C.; Krueger, S.; Panak, P. J.;
The pH-dependent (pH 2 - 4) formation of aqueous Am(III) complexes with formate (Form) is studied by EXAFS, iterative target transformation factor analysis (ITFA) and by quantum chemical calculations [1]. According to thermodynamical calculations three complexes (aq. Am3+, AmForm2+, AmForm2+) coexist and change their fractions, so that EXAFS spectral mixtures occur. A maximal spectral change of only 9% is observed between the different Am LIII-edge EXAFS spectra, which rules out the direct use of conventional shell fit analysis for structural investigation prior to the decomposition of the spectra into the single spectral components by ITFA. By combining pH-speciation calculations with quantum chemistry, the pH-dependent number of coordinated water and formate molecules is calculated and used as constraint for a modified ITFA-approach. The decomposition results in the separate spectral contributions of the exchanged molecules, hence the signal of a coordinated water and a monodentate coordinated formate molecule for which the structural parameters are determined by shell-fitting and are compared with twelve complex structures gained by quantum chemical calculations. Methodologically consistent, the prevailing coordination numbers are 9, 9 and 8 for the aq. Am3+, AmForm2+ and AmForm2+ complexes, respectively [2]. Low concentrations of species with other coordination numbers and modes cannot be excluded, as energy differences obtained by our quantum chemical calculations are small [2].

This work shows the power of the proposed ITFA-framework in obtaining structural information for weak ligand systems like formate, where conventional EXAFS data analysis fails due to the lower spectroscopic resolution in analysing mixtures of metal species.


References
[1] Rossberg et al., Anal. Bioanal. Chem. 376, 631-638 (2003).
[2] Fröhlich et al., Inorg. Chem. submitted (2017).
Keywords: EXAFS, iterative target transformation factor analysis, ITFA, Americium
  • Lecture (Conference)
    8th Workshop on Speciation, Techniques, and Facilities for Radioactive Materials at Synchrotron Light Sources, 11.-13.04.2017, Oxford, United Kingdom

Publ.-Id: 25217 - Permalink


Li, Co, Nd ... - Strategische Metalle für die Elektromobilität
Rudolph, M.ORC
Elektromobilität ist zurzeit in aller Munde; von eAutos, eBikes und Pedelecs hat jeder schon gehört. Die 32. Hochschultage Physik widmen sich dem gegenwärtigen Stand der Technik und der Zukunft dieses spannenden Forschungsgebietes. Vortragende aus Wissenschaft und Industrie greifen ein breites Spektrum an Aspekten auf, das sicherlich Anregungen für lebhafte Diskussionen bietet.
Die Veranstaltung richtet sich nicht nur an Lehrerinnen und Lehrer, sondern auch an die breite Öffentlichkeit, an Studierende und natürlich auch an die Mitglieder des Fachbereichs Physik.
  • Invited lecture (Conferences)
    32. Hochschultage Physik, 13.-14.02.2017, Marburg, Deutschland

Publ.-Id: 25216 - Permalink


Als Ingenieur in der Forschung - an der Grenzfläche von Wissenschaft, Gesellschaft und Anwendung
Rudolph, M.ORC
Ingenieure sind vielseitige Problemlöser und daher sehr gefragt in der Forschung, sowohl in Industrie wie auch in der Wissenschaft. Noch bis ins 19. Jahrhundert aber waren Ingenieure nicht wirklich geduldet als Wissenschaftler, nicht ohne Grund ist der Doktorgrad der Ingenieurwissenschaften in Deutschland seit dem als einziger nicht lateinisch und versehen mit einem Bindestrich, also Dr.-Ing. und nicht Dr. rer. tech. Der moderne Ingenieur ist aber schon längst ein angewandter Naturwissenschaftler und nicht nur geschickter Tüftler. Der Beitrag soll anhand der eigenen Erfahrungen des Vortragenden einen Einblick geben über die spannenden Themen eines Ingenieurs in der Forschung. Ganz speziell werden darüber hinaus die Felder der Grenzflächenverfahrenstechnik und der Ressourcentechnologie vorgestellt und aufgegriffen. Dabei soll auch das Spannungsfeld aus Wissenschaft, Gesellschaft und Anwendung beleuchtet werden.
  • Invited lecture (Conferences)
    VDI suj Freiberg - Stammtisch, 09.01.2017, Freiberg, Deutschland

Publ.-Id: 25215 - Permalink


Targeting stem cells in radiation oncology
Coppes, R.; Dubrovska, A.;
At the annual conference of the Association for Radiation Research held in Oxford 26-28 June 2017, one session focused on the potential of targeting stem cells in radiation oncology. Cancer stem cells (CSCs) are highly tumorigenic cells capable to self-renew and to give rise to all other tumour cells. Emerging clinical evidence links CSCs to the risk of tumour relapse and suggests that therapeutic targeting of CSC populations in combination with radiotherapy might be a promising approach to improve local tumour control. This editorial outlines the concept of cancer stem cells in radiation biology and the main avenues for tumour radiosensitisation by anti-CSC therapies.
Keywords: Cancer stem cells, Radiotherapy, Biomarker, Prediction, Radiosensitisation

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Publ.-Id: 25214 - Permalink


Multistage bioassociation of uranium(VI) on a halophilic archaeum investigated with luminescence spectroscopic and microscopic techniques
Bader, M.; Steudtner, R.; Drobot, B.; Cherkouk, A.;
Luminescence spectroscopy and microscopy are powerful tools to study the chemistry of f-elements (actinides – An, lanthanides – Ln) in trace concentration. Manifold operating modes (e.g. steady-state, time-resolved, laser-induced, site-selective, cryogenic, etc.) can be used to investigate the environmental behaviour of An/Ln in various geological and biological systems. In this study the halophilic archaeum Halobacterium noricense DSM-15987T, which commonly occurs in rock salt [1], a potential host rock formation for the deep geological disposal of radioactive waste, was used to characterize its interaction processes with uranium(VI). The bioassociation showed differences regarding initial uranium concentration (30 and 85 µM) and incubation time (up to two weeks). The lower uranium concentration caused a multistage association behaviour with a desorption phase after 5 h of exposure to uranium. A further difference provoked by uranium concentration was the cell agglomeration. This formation was pronounced at higher uranium(VI) concentration. For lower uranium(VI) concentration agglomerate formation took longer, but still occurred. To understand these processes on a molecular level, time-resolved laser-induced fluorescence spectroscopy at low temperature of 153 K (cryo-TRLFS) was applied. Changes detected in the batch experiments were confirmed with cryo TRLFS. The spectroscopic analyses showed the involvement of a polynuclear carboxylate species and the presence of a meta-autunite like uranium(VI) mineral phase [2]. A fraction analysis revealed that the biomineralization process (formation of meta-autunite) is more pronounced at lower uranium(VI) concentration. At the higher uranium(VI) concentration of 85 µM polynuclear carboxylate species were dominating. This could be explained with the higher toxicity of uranium(VI) and the accompanying cell agglomeration, which was more pronounced at higher uranium(VI) concentration. In combination with other spectroscopic (e.g. infrared spectroscopy) and microscopic tools (e.g. scanning electron microscopy) the applied luminescence methods were essential for a better understanding of the bioassociation process of uranium(VI) to cells of the halophilic archaeon.

[1] A. Gramain, Environ. Microbiol. 2011, 13, 2105-2121. [2] M. Bader, submitted to Environ. Sci. Technol. [3] S. Fröls, Biochem. Soc. Trans. 2013, 41, 393-398.
  • Poster
    ANAKON 2017, 03.-06.04.2017, Tübingen, Deutschland

Publ.-Id: 25213 - Permalink


Chemical speciation of trivalent lanthanides and actinides in body fluids
Barkleit, A.ORC; Wilke, C.
In case of incorporation into the human body, heavy metals and radionuclides potentially represent serious health risks due to their chemo- and radiotoxicity. In order to assess their toxicological behavior, such as transport, metabolism, deposition, and elimination from the human organisms, the understanding of their in vivo chemical speciation on a molecular level is crucial. In order to improve our understanding of the behavior of trivalent actinides (An(III)) and lanthanides (Ln(III)) in the human body, the present study focuses on the chemical speciation of An(III) and Ln(III) in the gastrointestinal tract. The human gastrointestinal system was simulated by using an in vitro digestion model, which is part of an international unified bioaccessibility method (UBM), developed by the Bioaccessibility Research Group of Europe (BARGE) [1]. To verify the model, natural human saliva samples were included in the speciation investigation [2].
The speciation of curium(III) (Cm(III)) and europium(III) (Eu(III)) in the gastrointestinal tract as well as in human natural saliva has been studied by means of time-resolved laser-induced fluorescence spectroscopy (TRLFS). The standard model body fluids and the natural saliva samples were spiked in vitro with Cm(III) and Eu(III) in trace metal concentrations.
The dominant chemical species in the human saliva was identified by a comparison of the natural human sample spectra with reference spectra obtained for synthetic saliva and individual components of the body fluid. Linear combination fitting analysis on the sample spectra indicates the formation of 60-90% inorganic- and 10-40% organic species of Cm(III)/Eu(III) in the salivary media. Ternary M(III) complexes containing phosphate and carbonate anions with the additional counter-cation calcium are formed as the main inorganic species. Complexes with the digestive enzyme α-amylase and the protein mucin (to a minor extent) represent the major part of the organic species. When the M(III) reached the stomach, the metal complexes were dissociated due to the high acidic conditions. That is, Cm(III) and Eu(III) are mainly present as the aquo ion, and only a small part (about 20%) is coordinated by the protein pepsin. When entering the intestine the metal ions are strongly bound by the protective protein mucin (about 65%) and inorganic ligands (about 35%; mainly carbonate and phosphate).

References
[1] J. Wragg, M. Cave, H. Taylor, N. Basta, E. Brandon, S. Casteel, C. Gron, A. Oomen, T. van de Wiele, British Geological Survey Open Report OR/07/027, Keyworth, Nottingham (2009) 90 pp.
[2] A. Barkleit, C. Wilke, A. Heller, T. Stumpf, A. Ikeda-Ohno, Dalton Trans. 46 (2017), 1593-1605
  • Invited lecture (Conferences)
    2nd International Conference on Pollutant Toxic Ions and Molecules, PTIM2017, 06.-09.11.2017, Caparica, Portugal

Publ.-Id: 25212 - Permalink


Speziation trivalenter f-Elemente in den Biofluiden des Verdauungssystems
Barkleit, A.ORC; Wilke, C.
Im Falle einer Inkorporation radioaktiver Stoffe entstehen ernsthafte gesundheitliche Risiken durch deren Chemo- und Radiotoxizität. Um die möglichen toxischen Effekte besser abschätzen und letztendlich verhindern zu können, ist es notwendig, die Speziation dieser Elemente im menschlichen Organismus auf molekularer Ebene zu verstehen. Die Speziation beeinflusst die Aufnahme, den Transport, den Metabolismus, die Einlagerung und die Ausscheidung der Elemente.
Die Gefahr einer oralen Aufnahme von Radionukliden besteht durch kontaminierte Lebensmittel oder Trinkwasser. Deshalb haben wir die Speziation von ausgewählten dreiwertigen Actiniden und Lanthaniden (Cm(III) und Eu(III)) in den Biofluiden des Verdauungstraktes näher untersucht. Die Biofluide wurden nach einer international anerkannten Methode (Unified Bioaccessibility Method, UBM) der Bioaccessibility Research Group of Europe (BARGE) synthetisch hergestellt [1]. Parallel dazu wurden natürliche menschliche Speichelproben zum Vergleich in die Untersuchungen einbezogen [2].
Die Speziatonsuntersuchungen von Cm(III) und Eu(III) in den Verdauungsfluiden wurden mit Hilfe der zeitaufgelösten laserinduzierten Fluoreszenzspektroskopie (Time-Resolved Laser-induced Fluorescence Spectroscopy, TRLFS) durchgeführt. Für Speichel wurde ermittelt, dass sich zum größten Teil (60-90%) anorganische Komplexe bilden, darunter dominiert ein ternärer Komplex mit Phosphat und Carbonat als Liganden und Calcium als weiterem Kation zum Ladungsausgleich. Organische Komplexe, hauptsächlich mit dem Verdauungsenzym α-Amylase, wurden ebenfalls nachgewiesen. Wenn die Speichelmischung den Magen erreicht, findet aufgrund des niedrigen pH-Wertes im Magen (pH<2) eine Dissoziation der Komplexe statt, Cm(III) und Eu(III) liegen dann hauptsächlich in Form ihrer Aquo-Komplexe vor. Aber ein kleiner Teil der Metallionen (ca. 20%) bildet trotz des niedrigen pH-Wertes Komplexe mit dem Verdauungsenzym Pepsin. Im Dünndarm, wo die eigentliche Verdauung und die Absorption der (Nähr-, aber auch Gift-)Stoffe in den Blutkreislauf stattfindet, werden die Metallionen hauptsächlich (ca. 65%) von dem Protein Muzin komplexiert, welches Hauptbestandteil der schützenden Schleimhaut (Mucosa) ist, und ca. 35% liegen als anorganische Spezies mit Phosphat und Carbonat als Liganden vor.

Referenzen

[1] J. Wragg et al., British Geological Survey Open Report OR/07/027, Keyworth, Nottingham, 2009, 90 pp.
2] A. Barkleit et al., Dalton Trans. 46, 2017, 1593-1605.
  • Lecture (Conference)
    GDCh-Wissenschaftsforum Chemie 2017, 10.-14.09.2017, Berlin, Deutschland

Publ.-Id: 25211 - Permalink


Speciation of trivalent actinides and lanthanides in digestive media
Barkleit, A.ORC; Wilke, C.
In case of incorporation into the human body, radionuclides potentially represent serious health risks due to their chemo- and radiotoxicity. In order to assess their toxicological behavior, such as transport, metabolism, deposition, and elimination from the human organisms, the understanding of their in vivo chemical speciation on a molecular level is crucial. Nevertheless, little is known about the speciation of not only trivalent actinides (An(III)) but also trivalent lanthanides (Ln(III)), non-radioactive chemical analogs of An(III), in human body fluids. In order to improve our understanding of the behavior of An(III) and Ln(III) in the human body, the present study focuses on the chemical speciation of An(III) and Ln(III) in the gastrointestinal tract. The human gastrointestinal system was simulated by using an in vitro digestion model, part of an international unified bioaccessibility method (UBM), developed by the Bioaccessibility Research Group of Europe (BARGE) (Wragg et al., 2009). To verify the model, natural human saliva samples were also investigated (Barkleit et al., 2017).
The speciation of trivalent curium (Cm(III)) and europium (Eu(III)) in the gastrointestinal tract and in human natural saliva has been studied by means of time-resolved laser-induced fluorescence spectroscopy (TRLFS). The standard model body fluids and the natural saliva samples were spiked in vitro with Cm(III) or Eu(III) with a trace metal concentration.
The dominant chemical species in the body fluids were determined by linear combination fitting (LCF) analysis based on the reference spectra for individual components in the body fluids. The results indicates the formation of inorganic- (60-90%) and organic species (10-40%) of Cm(III)/Eu(III) in the salivary media. Ternary M(III) complexes containing phosphate and carbonate anions with the additional counter-cation calcium is found to be the main inorganic species, while the complexes with the digestive enzyme α-amylase and the protein mucin represent the major part of the organic species.
When the M(III) reached the stomach, the metal complexes are dissociated due to the high acidic conditions in the stomach. That is, Cm(III) and Eu(III) are mainly present as aquo complexes, while a small part (about 20%) is coordinated by the protein pepsin. When entering the intestine the M(III) strongly interact with the protective protein mucin (about 65%) and inorganic ligands (mainly carbonate and phosphate).
These speciation results in different body fluids of the gastrointestinal tract pointed out that An(III) and Ln(III) are coordinated by both inorganic and organic molecules in the human digestive system. Proteins (e.g., α-amylase, pepsin, mucin) would be the important organic binding partners. Furthermore, ternary inorganic complexes containing phosphate and carbonate anions with the additional counter-cation calcium are expected to be formed as the main inorganic species in the whole body fluids.

Wragg, J., Cave, M., Taylor, H., Basta, N., Brandon, E., Casteel, S., Gron, C., Oomen, A., van de Wiele, T., 2009. British Geological Survey Open Report OR/07/027, Keyworth, Nottingham, 90 pp.
Barkleit, A., Wilke, C., Heller, A., Stumpf, T., Ikeda-Ohno, A., 2017. Trivalent f-elements in human saliva: a comprehensive speciation study by time-resolved laser-induced fluorescence spectroscopy and thermodynamic calculations. Dalton Trans. 46, 1593-1605
  • Lecture (Conference)
    International Conference on Environmental Radioactivity ENVIRA2017, 29.05.-02.06.2017, Vilnius, Lithuania

Publ.-Id: 25210 - Permalink


Uranium mining, resulting ecological problems and references to spectroscopic methods
Baumann, N.;
Ecological problems resulting from the reckless uranium mining in Saxony and Thuringia within approximately 45 years are illustrated, and contributions in determination of these problems by the spectroscopic methods TRFLS and EXAFS are showed.
Keywords: uranium, speciation, migration and sorption behavior, TRLFS, EXAFS
  • Invited lecture (Conferences)
    Invited presentation, 03.03.2017, Sriracha, Thailand

Publ.-Id: 25209 - Permalink


XAFS and XRD studies on tetravalent actinides in zirconia- and zircon-based ceramics
Hennig, C.; Weiss, S.; Ikeda-Ohno, A.; Gumeniuk, R.; Scheinost, A. C.;
Ceramic material is under discussion to be an alternative to borosilicate glass for the immobilization of nuclear waste. The corrosion resistance of ceramic material can increase over several magnitudes compared to glass. A homogenous mixture of the actinide and the ceramics precursor is essential to supress phase segregation which may weaken the dissolution resistance under the conditions of a nuclear waste repository. We investigated different sol-gel preparation routes of zirconia (ZrO2) and zircon (ZrSiO4) based ceramics.
Laboratory studies were accompanied by X-ray absorption spectroscopy (XAS) performed at the Rossendorf Beamline (ROBL). The beamline has broadened its experimental capacities with a 6-circle diffractometer which was used in this study for powder X-ray diffraction (XRD) experiments. Among the synthesis attempts, an acetate-base route seems to support the homogeneity of the precursor for zirconia-based ceramics, most likely because An(IV) and Zr(IV) show the same complexes in the sols [1,2]. X-ray absorption spectroscopy reveals that acetate supported An(IV) clusters are structurally very close to the zirconia structure units [3] and remain obviously intact when entering the zirconia ceramics. X-ray powder diffraction measurements show that this synthesis route reduces phase segregation in zirconia ceramics during thermal treatment. The host lattice needs a certain flexibility to tolerate the introduction of An(IV) ions. However, zirconia has a rigid structure which limits the intercalation of An(IV). The synthesis of zircon-based ceramics is faced with the problem that ZrSiO4 has no extended phase range in the ZrO2-SiO2 system and appears therefore in equilibrium with one of the limiting species. However, zircon shows a large structural flexibility. Therefore, zircon-based ceramics can be synthesized in a way that it forms unlimited solid solutions with An(IV).
Keywords: EXAFS, XRD, ZrO2, ZrSiO4, ceramics, tetravalent actinides
  • Lecture (Conference)
    Actinide XAS 2017, 11.-13.04.2017, University of Oxford, United Kingdom

Publ.-Id: 25208 - Permalink


Study of thermal hydraulics in a fuel element mock-up during dry-out with a thermal anemometry grid sensor
Arlit, M.; Schleicher, E.; Hampel, U.;
The paper presents investigation results on the cooling effect of rising steam on heated rods during a loss of cooling accident scenario in a fuel element mock-up in the spent fuel pool. Therefore, the newly developed thermal anemometry grid sensor was used. With the measured time course of gas-phase temperature and velocity in the subchannels the convection cooling of the rods by steam was verified.
  • Contribution to proceedings
    48th Annual Meeting on Nuclear Technology, 16.-17.05.2017, Berlin, Deutschland
    Proceedings of the 48th Annual Meeting on Nuclear Technology

Publ.-Id: 25207 - Permalink


Modeling of FREYA Fast Critical Experiments with the Serpent Monte Carlo Code
Fridman, E.; Kochetkov, A.; Krása, A.;
The FP7 EURATOM project FREYA has been executed between 2011 and 2016 with the aim of supporting the design of fast lead-cooled reactor systems such as MYRRHA and ALFRED. During the project, a number of critical experiments were conducted in the VENUS-F facility located at SCK•CEN, Mol, Belgium.
The Monte Carlo code Serpent was one of the codes applied for the characterization of the critical VENUS-F cores. Four critical configurations were modeled with Serpent, namely the reference critical core, the clean MYRRHA mock-up, the full MYRRHA mock-up, and the critical core with the ALFRED island.
This paper briefly presents the VENUS-F facility, provides a detailed description of the aforementioned critical VENUS-F cores, and compares the numerical results calculated by Serpent to the available experimental data. The compared parameters include keff, point kinetics parameters, fission rate ratios of important actinides to that of U235 (spectral indices), axial and radial distribution of fission rates, and lead void reactivity effect.
The reported results show generally good agreement between the calculated and experimental values. Nevertheless, the paper also reveals some noteworthy issues requiring further attention. This includes the systematic overprediction of reactivity and systematic underestimation of the U238 to U235 fission rate ratio.
Keywords: Serpent, Monte Carlo, FREYA, VENUS-F, critical experiments, lead fast reactor

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Publ.-Id: 25206 - Permalink


Analysis for Optimum Conditions for Recovery of Valuable Metals from E-waste Through Black Copper Smelting
Shuva, M. A. H.; Rhamdhani, M. A.; Brooks, G. A.; Masood, S.; Reuter, M. A.; Firdaus, M.;
Declining grade of primary ores and resource efficiency have led us to process more alternative metal resources such as e-waste. One of the processing routes for extracting valuable metals from e-waste is through the black copper smelting. However, the underlying knowledge of the thermodynamics behaviour of the valuable metals contained in e-waste during smelting are limited which prevent us from developing an optimised process to recover all the metals. These different metals clearly will have different favourable conditions for their extraction. To illustrate this, the distribution behaviour of germanium (Ge) and palladium (Pd) between liquid copper and ferrous-calcium-silicate slag during black copper smelting was analysed. It was demonstrated that oxygen partial pressure and slag composition affect the partitioning of these metals to the copper phase and the favourable slag chemistry for recovering these metals is opposing. Considering the available thermodynamic data of these metals, an analysis for the optimum conditions is presented.
Keywords: Resources efficiency E-waste Black copper Metal recovery
  • Book chapter
    Hwang, Jiang, Kennedy, Yücel, Pistorius; Seshadri, Zhao, Gregurek; Keskinkilic: The Minerals, Metals & Materials Series, New York: Springer International Publishing, 2017, 978-3-319-51339-3, 419-427
    DOI: 10.1007/978-3-319-51340-9_41

Publ.-Id: 25205 - Permalink


Individualized early death and long-term survival prediction after stereotactic radiosurgery for brain metastases of non-small cell lung cancer: Two externally validated nomograms
Zindler, J.; Jochems, A.; Lagerwaard, F.; Beumer, R.; Troost, E.; Eekers, D.; Compter, I.; van der Toorn, P.-P.; Essers, M.; Oei, B.;
Introduction: Commonly used clinical models for survival prediction after stereotactic radiosurgery (SRS) for brain metastases (BMs) are limited by the lack of individual risk scores and disproportionate prognostic groups. In this study, two nomograms were developed to overcome these limitations.
Methods: 495 patients with BMs of NSCLC treated with SRS for a limited number of BMs in four Dutch radiation oncology centers were identified and divided in a training cohort (n = 214, patients treated in one hospital) and an external validation cohort n = 281, patients treated in three other hospitals). Using the training cohort, nomograms were developed for prediction of early death (<3 months) and long-term survival (>12 months) with prognostic factors for survival. Accuracy of prediction was defined as the area under the curve (AUC) by receiver operating characteristics analysis for prediction of early death and long term survival. The accuracy of the nomograms was also tested in the external validation cohort.
Results: Prognostic factors for survival were: WHO performance status, presence of extracranial metastases, age, GTV largest BM, and gender. Number of brain metastases and primary tumor control were not prognostic factors for survival. In the external validation cohort, the nomogram predicted early death statistically significantly better (p < 0.05) than the unfavorable groups of the RPA, DS-GPA, GGS, SIR, and Rades 2015 (AUC = 0.70 versus range AUCs = 0.51–0.60 respectively). With an AUC of 0.67, the other nomogram predicted 1 year survival statistically significantly better (p < 0.05) than the favorable groups of four models (range AUCs = 0.57–0.61), except for the SIR (AUC = 0.64, p = 0.34). The models are available on www.predictcancer.org.
Conclusion: The nomograms predicted early death and long-term survival more accurately than commonly used prognostic scores after SRS for a limited number of BMs of NSCLC. Moreover these nomograms enable individualized probability assessment and are easy into use in routine clinical practice.
Keywords: Individualized brain metastases Stereotactic radiosurgery Prognostic models

Publ.-Id: 25204 - Permalink


PIConGPU the 3D3V Particle-in-Cell Code Developed at HZDR – A Status Update
Huebl, A.ORC; Garten, M.; Pausch, R.; Matthes, A.; Branco, J.; Steiniger, K.; Burau, H.; Grund, A.; Debus, A.; Kluge, T.; Widera, R.; Bussmann, M.
PIConGPU is currently the fastest particle-in-cell code in the world. New physics models are continuously developed and, after thorough testing, included in our open-source software.

In this talk we will give an overview on the recent upgrades in PIConGPU, covering new ionization schemes including ADK, Keldysh and collisional ionization, a QED and bremsstrahlung module that brings photons to the code, and various new laser implementations to better model lasers used in experiments and to enable the simulation of novel light source concepts like TWTS. We will present various synthetic diagnostic methods such as the spectrally resolved radiation detectors, the in-situ phase space diagnostic and our ParaTAXIS framework, which is able to simulate small angle photon scattering of an external x-ray pulse probing laser-driven solid-density targets. Furthermore, we will briefly discuss numerous code improvements which boost performance, unify data exchange and analysis via the openPMD standard for open, reproducible science, and our steerable live visualization. Finally we will showcase several simulations ranging from laser wakefield acceleration via ionization injection, to ion acceleration via laser interaction with spherical, perfectly isolated, mass-limited targets (both experimentally realized) to radiation signatures of a shear surface instability.
Keywords: Simulation, LPA, PIC, PIConGPU, FLOSS, Open Source, Modeling, Synthetic Diagnostics
  • Lecture (Conference)
    Third MT student retreat, Third Annual Matter & Technologies Meeting, 30.-31.01.2017, Darmstadt, Germany

Publ.-Id: 25203 - Permalink


In-Situ Non-LTE Population Kinetics in PIConGPU
Huebl, A.ORC; Chung, H.-K.; Garten, M.; Kluge, T.; Widera, R.; Burau, H.; Grund, A.; Pausch, R.; Cowan, T.; Schramm, U.; Bussmann, M.
Laser-ion acceleration is a promising concept towards compact high-gradient particle acceleration. Most laser-ion acceleration mechanisms are operating with optically over-dense targets and are sensitive to emerging plasma instabilities, negatively impacting stability, control and beam quality. In order to gain higher control over the acceleration process, upcoming pump-probe experiments at the European XFEL and and adequate modeling in full 3D simulations can be deployed. This poster describes our efforts on integrating SCFLY's collisional-radiative non-LTE model into the electro-magnetic particle-in-cell code PIConGPU.
Keywords: LPA, ion-acceleration, simulation, photon science, gpu, non-LTE, probing, modeling
  • Poster
    ICTP-IAEA School on Atomic Processes in Plasmas, 27.02.-03.03.2017, Trieste, Italy

Publ.-Id: 25202 - Permalink


Proton implantation for electrical insulation of the InGaAs/InAlAs superlattice material used in 8–15 μm-emitting quantum cascade lasers
Kirch, J. D.; Kim, H.; Boyle, C.; Chang, C.-C.; Mawst, L. J.; Lindberg Iii, D.; Earles, T.; Botez, D.; Helm, M.; von Borany, J.; Akhmadaliev, S.; Böttger, R.; Reyner, C.;
We demonstrate the conversion of lattice-matched InGaAs/InAlAs quantum-cascade-laser (QCL) active-region material into an effective current-blocking layer via proton implantation. A 35-period active region of an 8.4 μm-emitting QCL structure was implanted with a dose of 5 × 10^14 cm−2 protons at 450 keV to produce a vacancy concentration of ∼10^19 cm−3. At room temperature, the sheet resistance, extracted from the Hall measurements, increases by a factor of ∼240 with respect to that of an unimplanted material. Over the 160–320 K temperature range, the activation energy of the implanted-material Hall sheet-carrier density is 270 meV. The significant increase in room-temperature sheet resistance indicates that upon implantation deep carrier traps have been formed in the InAlAs layers of the superlattice. Fabricated mesas show effective current blocking, at voltages ≥10 V, up to at least 350 K. Thus, the implanted InGaAs/InAlAs superlattices are highly resistive to at least 350 K heat sink temperature. Such implanted material should prove useful for effective current confinement in 8–15 μm-emitting InP-based single-emitter QCL structures as well as in resonant leaky-wave coupled phase-locked arrays of QCLs.
Keywords: Quantum cascade lasers, Ion Implantation, Protons, Superlattices, Leakage currents, Carrier mobility

Publ.-Id: 25201 - Permalink


Our strategic approach: Reactive transport modelling based on parameters obtained from batch and GeoPET column experiments: example from leaching of a fractured drill core
Karimzadeh, L.; Kulenkampff, J.; Schymura, S.; Eichelbaum, S.; Lippmann-Pipke, J.;
Abstract

The EU-funded research project BIOMOre[1] is designed to develop a new technological concept for the in-situ recovering of copper from deep European Kupferschiefer ore deposits by using controlled stimulation of pre-existing fractures in combination with in-situ bioleaching. The BIOMOre project mainly focuses on the leaching experiments in lab and field scale and the related reactive transport modeling including the required backcoupling from geochemical reactions on the hydrodynamics as well as the upscaling. We here present most recent, preliminary results that focus on reactive transport simulations on a drill core sample in 4D (3D+t). While we still use synthetic porosity and velocity fields, the model is capable of later imported velocity and effective porosity fields obtained from the transport process visualization method, GeoPET. This technique has been established by members of the Reactive Transport Division of the HZDR in the past decade and allows the direct, non-destructive, quantitative spatiotemporal visualization of (reactive) transport processes in natural geological media on drill-core scale [2-6].
A mechanically induced fracture was designed with a geomechanical shear test in a calciferous sandstone drill core sample obtained from the Kupferschiefer ore formation. While the long term leach experiment is still ongoing the pH value and preliminary Ca+ and Cl- contents from the breakthrough are aligned with those from the reactive transport modelling conducted by means of iCP[7] (an interface coupling of the finite element based code COMSOL Multiphysics® with the geochemical code PhreeqC). The model consideres mineral leaching due to the injection of an acidic solution with pH of 1.5 to the fracture. Currently the flow is still simulated by the Forchheimer equation [8] in matrix and fracture. The chemical processes considered in the model are kinetically controlled mineral dissolution and precipitation in the porous media simulated by means of PHREEQC[9] and advective-dispersive transport in the fracture and matrix diffusion in the rock mass calculated by COMSOL Multiphysics. Calcite dissolution and gypsum precipitation were monitored in the results of the model.
Our further tasks in the project will consider more realistic structure geometry of rock core sample (fracture and matrix) and quantified advective distributions obtained from GeoPET.
Keywords: Reactive transport modeling, GeoPET, In-situ leaching, iCP
  • Invited lecture (Conferences)
    7th Reactive Transport PhD Workshop, 23.02.2017, Leipzig, Germany

Publ.-Id: 25200 - Permalink


Non-invasive determination of gas phase dispersion coefficients in bubble columns using periodic gas flow modulation
Döß, A.; Schubert, M.; Bieberle, A.; Hampel, U.;
Non-uniform bubble size and liquid velocity distribution in bubble columns lead to gas phase dispersion. This gas phase backmixing is quantitatively modelled in the axial gas dispersion model by the axial gas dispersion coefficient. However, only few gas phase dispersion data are currently available since experimental investigations are expensive and require the application of suitable gas tracers and their reliable detection. In this study a new approach is introduced, which is based on a lock-in measurement of gas fraction modulation. Experiments were carried out in a bubble column of 100 mm diameter operated with air/water and air/glycol-water, respectively. Gas holdup was measured via gamma-ray densitometry in synchronization with the modulated inlet flow. The axial dispersion model was adopted to determine the gas phase dispersion coefficient from phase shift and amplitude damping of the gas holdup frequency response. A sensitivity analysis was performed to derive a proper modulation scheme. The calculated gas phase dispersion coefficients show excellent agreement with data from literature.
Keywords: Bubble column, gas phase dispersion, axial dispersion coefficient, gas flow modulation, frequency response analysis, gamma-ray densitometry

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  • Secondary publication expected

Publ.-Id: 25198 - Permalink


Isothermal titration calorimetry of selenium(IV) sorption processes onto iron oxides
Jordan, N.; Reder, C.; Foerstendorf, H.; Drobot, B.; Fahmy, K.;
As a consequence of nuclear waste disintegration heat, elevated temperatures in the near field of geological repositories may influence radionuclide retention at interfaces significantly. However, experimental data on free Gibbs energy (ΔRG), enthalpy (ΔRH) and entropy (ΔRS) of reactions of most radionuclides including fission products such as 79Se are sparse. Using the Se(IV)/maghemite system, we intended to show that microcalorimetry can provide these thermodynamic parameters with high accuracy and in a manner that allows studying various radionuclides.
The detection of the heat of the sorption reaction of Se(IV) onto maghemite was accomplished by isothermal titration calorimetry. Experiments were carried out at temperatures ranging from 20 to 40 °C and at pH 5. The heat flow was recorded as a function of time during the titrations (Figure 1).
The adsorption process was found to be exothermic, in agreement with findings of batch experiments. As the number of injections increases, the signal continuously decreases. Indeed, during the course of injections, the binding sites of maghemite are being gradually saturated by Se(IV), and the exothermic effect gets consequently reduced until only the heat of dilution is detected.
The heat (in J) related to each injection can be derived from single peak areas. The sum of all injections represents the corresponding enthalpy of the overall reaction (ΔRH). Additionally, the molar enthalpy of adsorption (J mol−1) can be determined and, thus, the number of adsorbed Se(IV) molecules as well. By applying the Langmuir isotherm, and assuming the proportionality of the maximum adsorption capacitiy qm to the mass to volume ratio, the Langmuir constant (log KL) can be derived.
In the future, spectroscopic techniques evidencing the nature of the adsorption process and the number of relevant species at the surface will be combined with microcalorimetry. Thus, a thermodynamic description of the selenium mobility in natural systems will be assessed with much more confidence and lower uncertainties.
  • Contribution to proceedings
    16th International Conference on the Chemistry and Migration Behaviour of Actinides and Fission Products in the Geosphere, 10.-15.09.2017, Barcelona, Spain
    Proceedings of MIGRATION 2017

Publ.-Id: 25197 - Permalink


Comparison of toxicity and outcome in advanced stage non-small cell lung cancer patients treated with intensity-modulated (chemo-)radiotherapy using IMRT or VMAT
Wijsman, R.; Dankers, F.; Troost, E. G. C.; Hoffmann, A. L.; van der Heijden, E. H. F. M.; de Geus-Oei, L. F.; Bussink, J.;
Retrospective evaluation of 188 advanced stage non-small cell lung cancer patients treated with IMRT or VMAT revealed a limited increase of moderate to severe acute esophageal toxicity after VMAT. Acute pulmonary toxicity and severe late toxicity were low. Overall survival did not differ between the IMRT and VMAT groups.
Keywords: Non-small cell lung cancer Intensity-modulated radiation therapy Volumetric-modulated radiation therapy Toxicity

Publ.-Id: 25196 - Permalink


Holographic QCD phase diagram with critical point from Einstein-Maxwell-dilaton dynamics
Knaute, J.; Yaresko, R.; Kämpfer, B.;
Supplementing the holographic Einstein-Maxwell-dilaton model of [O. DeWolfe, S.S. Gubser, C. Rosen, Phys. Rev. D83 (2011) 086005; O. DeWolfe, S.S. Gubser, C. Rosen, Phys. Rev. D84 (2011) 126014] by input of lattice QCD data for 2+1 flavors and physical quark masses for the equation of state and quark number susceptibility at zero baryo-chemical potential we explore the resulting phase diagram over the temperature-chemical potential plane. A first-order phase transition sets in at a temperature of about 112 MeV and a baryo-chemical potential of 989 MeV. We estimate the accuracy of the critical point position in the order of approximately 5% by considering different low-temperature asymptotics for the second-order quark number susceptibility. The critical pressure as a function of the temperature has a positive slope, i.e. the entropy per baryon jumps up when crossing the phase border line from larger values of temperature/baryo-chemical potential, thus classifying the phase transition as a gas-liquid one. The updated holographic model exhibits in- and outgoing isentropes in the vicinity of the first-order phase transition.

Publ.-Id: 25195 - Permalink


A novel tumor pretargeting system based on complementary L-configured oligonucleotides
Schubert, M.; Bergmann, R.; Förster, C.; Sihver, W.; Vonhoff, S.; Klussmann, S.; Bethge, L.; Walther, M.; Schlesinger, J.; Pietzsch, J.; Steinbach, J.; Pietzsch, H.-J.;
Unnatural mirror image L-configured oligonucleotides (L-ONs) are a convenient substance class for the application as complementary in vivo recognition system between a tumor specific antibody and a smaller radiolabeled effector molecule in pretargeting approaches. The high hybridization velocity and defined melting conditions are excellent preconditions of the L-ON based methodology. Their high metabolic stability and negligible unspecific binding to endogenous targets are superior characteristics in comparison to their D-configured analogs. In this study, a radiopharmacological evaluation of a new L-ONs based pretargeting system using the epidermal growth factor receptor (EGFR) specific antibody cetuximab (C225) as target-seeking component is presented. An optimized PEGylated 17mer-L-DNA was conjugated with p-SCN-Bn-NOTA (NOTA’) to permit radiolabeling with the radionuclide 64Cu. C225 was modified with the complementary 17mer-L-DNA (c-L-DNA) strand as well as with NOTA’ for radiolabeling and use for positron emission tomography (PET). Two C225 conjugates were coupled with 1.5 and 5.0 c-L-DNA molecules, respectively. In vitro characterization was done with respect to hybridization studies, competition and saturation binding assays in EGFR expressing squamous cell carcinoma cell lines A431 and FaDu. The modified C225 derivatives exhibited high binding affinities in the low nanomolar range to the EGFR. PET and biodistribution experiments on FaDu tumor bearing mice with directly 64Cu-labeled NOTA’3-C225-(c-L-DNA)1.5 conjugate revealed that a pretargeting interval of 24 h might be a good compromise between tumor accumulation, internalization, blood background, and liver uptake of the antibody. Despite internalization of the antibody in vivo pretargeting experiments showed an adequate hybridization of 64Cu-radiolabeled NOTA’-L-DNA to the tumor located antibody and a good tumor-to-muscle ratio of about 11 resulting in a clearly visible image of the tumor after 24 h up to 72 h. Furthermore, low accumulation of radioactivity in organs responsible for metabolism and excretion was determined. The presented results indicate a high potential of complementary L-ONs for the pretargeting approach which can also be applied to therapeutic radionuclides such as 177Lu, 90Y, 186Re or 188Re.
Keywords: tumor pretargeting, mirror-image L-configured oligonucleotide, epidermal growth factor receptor (EGFR), cetuximab (C255), Cu-64, PET imaging, radioimmunotherapy

Publ.-Id: 25194 - Permalink


The Beautiful Molecule: 30 Years of C60 and its Derivatives
Acquah, S. F. A.; Penkova, A. V.; Markelov, D. A.; Semisalova, A. S.; Leonhardt, B. E.; Magi, J. M.;
In 1996 Sir Harold W. Kroto, Robert F. Curl and Richard E. Smalley were honored with the Nobel Prize in Chemistry for the discovery of fullerenes. The advent of these new forms of carbon heralded a race to understand the physical and chemical properties. C60 is virtually insoluble in polar solvents but is partially soluble in benzene, toluene, and carbon disulfide. This made the processing of fullerenes for new applications fairly problematic. However, the physical and chemical properties of these cage structures may be tailored for a wide range of applications. Some of the difficulties in processing have been overcome by using novel fullerene derivatives. The functionalization of the fullerene core with different chemical moieties provided a vector towards potential applications in drug delivery, optoelectronics, electrochemistry and organic photovoltaics. In this review, we will take a closer look at the features of some of the fullerene derivatives that have reinvigorated the field of fullerene research. Water-soluble polyhydroxylated fullerenes such as fullerenol have demonstrated the potential for good electron transfer and optical transmission, while hydrophobic fullerene derivatives have shown promising avenues for catalytic applications.
2015 marked the 30th anniversary of the discovery of fullerenes, with celebrations around the world including an event by the Royal Society of Chemistry, bringing together many of Sir Harold Kroto’s former students. The event also coincided with the recent discovery of C60+ in space after a complex twenty-year search. It is with sadness that we, Harry’s Research Group at Florida State University, and his international collaborators, reflect on the passing of Sir Harold Kroto. His dedication to science and commitment to science communication through the VEGA Science Trust and the Global Educational Outreach for Science Engineering and Technology (GEOSET) initiative help to raise awareness of the challenges for science in the modern world. We will continue to inspire young students through outreach activities he initiated.
Keywords: Fullerene, fullerenol, metallofullerenes, mechanical properties, electrical properties

Publ.-Id: 25193 - Permalink


Impact of U(VI) on the metabolism of plant cells as a function of the U(VI) concentration: An isothermal microcalorimetric and spectroscopic study
Sachs, S.; Fahmy, K.; Oertel, J.; Geipel, G.; Bok, F.;
Knowledge of the radionuclide transfer in the environment up to the food chain is the basis for a reliable safety assessment of potential nuclear waste disposal sites as well as for the evaluation of suitable remediation measures for radioactively contaminated areas, e.g., NORM sites. The uptake of radionuclides by plants is often described by transfer factors. To improve the knowledge of the underlying processes, the interactions of plants with radionuclides, e.g., uranium, are investigated on a molecular level (e.g., Günther et al., 2003, Laurette et al., 2012, Geipel and Viehweger, 2015). We studied the interaction of U(VI) with canola cells (Brassica napus) and focused on the concentration-dependent influence of U(VI) on the cell metabolism. Isothermal microcalorimetry was used as an extremely sensitive tool to monitor the metabolic heat flow of the cells in the absence and presence of U(VI). The cell viability was studied using the MTT test (Mosmann, 1983). The speciation of U(VI) in the nutrient medium was determined by time-resolved laser-induced fluorescence spectroscopy (TRLFS) and thermodynamic modeling to correlate the impact of U(VI) on the cell metabolism with its speciation.
Isothermal microcalorimetry is a highly sensitive monitor of the concentration and probably speciation-dependent U(VI) toxicity in plant cells. The metabolic response of the cells correlates very well with their mitochondrial activities. This opens possibilities to distinguish between chemo- and radiotoxic effects of U(VI) in calorimetric experiments.
Keywords: Plants, metabolism, uranium, isothermal microcalorimetry, TRLFS, thermodynamic modeling
  • Contribution to proceedings
    4th International Conference on Radioecology and Environmental Radioactivity, 03.-08.09.2017, Berlin, Germany, 978-2-9545237-7-4
  • Poster
    4th International Conference on Radioecology and Environmental Radioactivity, 03.-08.09.2017, Berlin, Germany

Publ.-Id: 25192 - Permalink


Prediction of countercurrent flow limitation and its uncertainty in horizontal and slightly inclined pipes
Murase, M.; Utanohara, Y.; Kusunoki, T.; Yamamoto, Y.; Lucas, D.; Tomiyama, A.;
We proposed prediction methods for countercurrent flow limitation (CCFL) in horizontal and slightly inclined pipes with one-dimensional (1-D) computations and uncertainty of computed CCFL. In this study, we applied the proposed methods to a full-scale pressurizer surge line [inclination angle theta = 0.6 deg, diameter D = 300 mm, and ratio of the length to the diameter (L/D) = 63] in a specific pressurized water reactor, performed 1-D computations and three-dimensional (3-D) numerical simulations, and found that uncertainties caused by effects of the diameter and fluid properties on CCFL were small. We also applied the proposed methods to experiments for hot-leg and surge line models (theta = 0 and 0.6 deg, D = 0.03 to 0.65 m, and L/D = 4.5 to 63) to generalize them, performed 1-D computations, and found that uncertainties caused by effects of theta and L on CCFL were large due to the setting error for theta and differences among experiments. This shows that a small-scale air-water experiment with the same theta and L/D as those in an actual plant is effective to reduce the uncertainty of CCFL prediction.
Keywords: PWR hot leg, pressurizer surge line, countercurrent flow limitation

Publ.-Id: 25189 - Permalink


Δ(1232) Dalitz decay in proton-proton collisions at T=1.25 GeV measured with HADES
Adamczewski-Musch, J.; Agakishiev, G.; Arnold, O.; Atomssa, E. T.; Behnke, C.; Berger-Chen, J. C.; Biernat, J.; Blanco, A.; Blume, C.; Böhmer, M.; Bordalo, P.; Chernenko, S.; Deveaux, C.; Dreyer, J.; Dybczak, A.; Epple, E.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Franco, C.; Friese, J.; Fröhlich, I.; Galatyuk, T.; Garzón, J. A.; Gill, K.; Golubeva, M.; Guber, F.; Gumberidze, M.; Harabasz, S.; Hennino, T.; Hlavac, S.; Höhne, C.; Holzmann, R.; Ierusalimov, A.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Karavicheva, T.; Kardan, B.; Koenig, I.; Koenig, W.; Kolb, B. W.; Korcyl, G.; Kornakov, G.; Kotte, R.; Krása, A.; Krebs, E.; Kuc, H.; Kugler, A.; Kunz, T.; Kurepin, A.; Kurilkin, A.; Kurilkin, P.; Ladygin, V.; Lalik, R.; Lapidus, K.; Lebedev, A.; Lopes, L.; Lorenz, M.; Mahmoud, T.; Maier, L.; Maurus, S.; Mangiarotti, A.; Markert, J.; Metag, V.; Michel, J.; Morozov, S.; Müntz, C.; Münzer, R.; Naumann, L.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Petousis, V.; Pietraszko, J.; Przygoda, W.; Ramos, S.; Ramstein, B.; Rehnisch, L.; Reshetin, A.; Rost, A.; Rustamov, A.; Sadovsky, A.; Salabura, P.; Scheib, T.; Schmidt-Sommerfeld, K.; Schuldes, H.; Sellheim, P.; Siebenson, J.; Silva, L.; Sobolev, Y. G.; Spataro, S.; Ströbele, H.; Stroth, J.; Strzempek, P.; Sturm, C.; Svoboda, O.; Tarantola, A.; Teilab, K.; Tlusty, P.; Traxler, M.; Tsertos, H.; Vasiliev, T.; Wagner, V.; Wendisch, C.; Wirth, J.; Zanevsky, Y.; Zumbruch, P.;
In this paper we report on the investigation of Δ(1232) production and decay in proton-proton collisions at a kinetic energy of 1.25 GeV measured with HADES. Exclusive dilepton decay channels ppe+e- and ppe+e-γ have been studied and compared with the partial wave analysis of the hadronic ppπ0 channel. They allow to access both Δ+ -> π0(e+e-γ)p and Δ+ -> pe+e- Dalitz decay channels. The perfect reconstruction of the well known π0 Dalitz decay serves as a proof of the consistency of the analysis. The Δ Dalitz decay is identified for the first time and the sensitivity to N-Δ transition form factors is tested. The Δ(1232) Dalitz decay branching ratio is also determined for the first time; our result is (4.19 +- 0.62 syst. +- 0.34 stat.) x 10-5, albeit with some model dependence.

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Publ.-Id: 25187 - Permalink


18F-fluorodeoxyglucose positron-emission tomography (FDG- PET)-Radiomics of metastatic lymph nodes and primary tumor in non-small cell lung cancer (NSCLC) – A prospective externally validated study
Carvalho, S.; Leijenaar, R.; Troost, E.; van Timmeren, J.; Oberije, C.; van Elmpt, W.; de Geus-Oei, L.; Bussink, J.; Lambin, P.;
Lymph node stage prior to treatment is strongly related to disease progression and poor prognosis in non-small cell lung cancer (NSCLC). However, few studies have investigated metabolic imaging features derived from pre-radiotherapy 18F-fluorodeoxyglucose (FDG) positron-emission tomography (PET) of metastatic hilar/mediastinal lymph nodes (LNs). We hypothesized that these would provide complementary prognostic information to FDG-PET descriptors to only the primary tumor (tumor).
Methods: Two independent cohorts of 262 and 50 node-positive NSCLC patients were used for model development and validation. Image features (i.e. Radiomics) including shape and size, first order statistics, texture, and intensity-volume histograms (IVH) (www.radiomics.org) were evaluated by univariable Cox regression on the development cohort. Prognostic modelling was conducted with a 10-fold cross-validated least absolute shrinkage and selection operator (LASSO), automatically selecting amongst FDG-PET-Radiomics descriptors from (1) tumor, (2) LNs or (3) both structures. Performance was assessed with the concordance-index. Development data are publicly available at www.cancerdata.org.
Results: Common SUV descriptors (maximum, peak, and mean) were significantly related to overall survival when extracted from LNs, as were LN volume and tumor load (summed tumor and LNs’ volumes), though this was not true for either SUV metrics or tumor’s volume. Feature selection exclusively from imaging information based on FDG-PET-Radiomics, exhibited performances of (1) 0.53 – external 0.54, when derived from the tumor, (2) 0.62 – external 0.56 from LNs, and (3) 0.62 – external 0.59 from both structures, including at least one feature from each sub-category, except IVH.
Conclusion: Combining imaging information based on FDG-PET-Radiomics features from tumors and LNs is desirable to achieve a higher prognostic discriminative power for NSCLC.
Keywords: PET, lymph nodes, Radiomics, Imaging analysis

Publ.-Id: 25186 - Permalink


Three-dimensional culture systems
Cordes, N.;
3D cell cultures appear in many different self-made and commercially available facets. A common denominator for some of them is that they enable cell growth in a more physiological environment than conventional 2D cell cultures. Unfortunately, validation of their suitability to do so and to fit to a particular scientific question is mostly missing. In this teaching lecture I will discuss validation strategies and data of comparative analyses between 2D, 3D and tumor xenografts of various processes such as signal transduction, DNA repair and others. Based on our long-standing experience, a large variety of endpoints can be determined and many methods can be conducted in 3D cell cultures. While this is sometimes not as easy as in 2D and also requires a bit more financial invest, the generated data reflect cell behavior in-vivo and thus have a higher clinically relevance. Further, we are able to address specific tumor features in detail. For example, malignant tumors show great genetic/epigenetic and morphological/cell biological heterogeneity. Another important point is the sparing of animal experiments based on our broad knowledge that human (patho)physiology is significantly different from mice (or other species). Many decades of in-vivo research have demonstrated that only a negligible proportion of therapeutic approaches could be translated from rodents to humans. In conclusion, 3D cell culture models can elegantly support our efforts to gain more knowledge for precision cancer medicine as they present powerful tools for generating more clinically relevant information. A broader implementation of the 3D methodology is likely to underscore our efforts to better understand tumor and normal cell radiation responses and foster identification of most critical cancer targets.
Keywords: 3D cell culture, radiobiology
  • Invited lecture (Conferences)
    ESTRO 2017, 05.-09.05.2017, Wien, Österreich

Publ.-Id: 25185 - Permalink


Discoidin Domain Receptor 1 controls GBM radiochemosensitivity by modulating autophagy
Klapproth, E.; Vehlow, A.; Cordes, N.;
Background: Glioblastoma multiforme (GBM) is characterized by genetic and epigenetic alterations in resistance-mediating genes and destructive infiltration of the surrounding brain. Cell adhesion molecules play an important role in therapy resistance. One of these cell adhesion molecules is the Discoidin Domain Receptor 1 (DDR1) facilitating binding to the extracellular matrix protein collagen type-1. Here, we evaluated the so far unknown role of DDR1 in GBM radiochemoresistance including analysis of the underlying molecular mechanisms.
Methods: DDR1 expression (tumor vs. normal) was investigated (Oncomine database). DDR1 targeting (DDR1-IN-1 inhibitor and siRNA) as single treatment and in combination with either irradiation or radiochemotherapy using Temozolomide (TMZ) was conducted to identify its radiochemosensitizing potential in GBM stem-like (GS-5, GS-8) and primary GBM cell populations (DK32, DK41, DK42) (Sphere Formation Assay, 0-6 Gy X-rays) as well as in an orthotopic GBM mouse model. Alterations of signal transduction upon DDR1 inhibition were examined by Western blotting and broad spectrum phosphoproteome analysis. A search for direct DDR1 binding partners was executed by sequential immunoprecipitation/mass spectrometry employing wildtype and truncated DDR1 variants and GST-pulldown.
Results: Database analysis revealed a 3-fold increased DDR1 expression in GBM compared with normal brain (Oncomine). GBM stem-like and patient-derived GBM cell cultures treated with DDR1-IN-1 showed significantly enhanced radiosensitivity in vitro. Intriguingly, a combined DDR1-IN-1/TMZ regimen plus irradiation significantly delayed tumor growth and prolonged survival of mice bearing orthotopic GBM. Mechanistically, a 14-3-3/Beclin-1 protein complex identified by MS/MS connects DDR1 to the pro-survival Akt-mTOR axis. Upon DDR1 inhibition, we observed dissociation of this protein complex followed by abrogated Akt-mTOR signaling, induction of LC3b expression and formation of LC3b-positive autophagosomes. Direct binding of 14-3-3 to DDR1 was confirmed by DDR1 deletion variants and GST-pulldown.
Conclusion: Our data demonstrate that DDR1 is a potential target in GBM and its pharmacological inhibition effectively mediates radiochemosensitization via induction of autophagy that is superior to the conventional therapy.
Keywords: GBM, DDR1, radiochemoresistance, autophagy
  • Contribution to proceedings
    Wolfsberg Meeting, 17.-19.06.2017, Ermatingen, Schweiz

Publ.-Id: 25184 - Permalink


Reduktion der adhäsions- und stress-bedingten Anpassung im Glioblastom durch beta1 integrin/JNK Doppelhemmung reduziert Radiochemoresistenz und Invasion
Vehlow, A.; Klapproth, E.; Storch, K.; Dickreuter, E.; Seifert, M.; Dietrich, A.; Bütof, R.; Temme, A.; Cordes, N.;
Fragestellung: Die schlechte Prognose von Glioblastoma multiforme (GBM) Patienten beruht maßgeblich auf Therapieresistenzen von GBM Stamm- und Tumorzellen und deren invasiven Ausbreitung im Gehirn. Hierbei spielen auch durch die Therapie induzierte Anpassungsmechanismen eine besondere Rolle. Um simultan zur Radiochemotherapie diese Anpassungsmechanismen zu hemmen, haben wir Überlebenssignalkaskaden über beta1 Integrine und die Stress-assoziierten c-Jun N-terminalen Kinasen (JNK) in GBM Zellen gehemmt und die Effektivität dieser Kombinationstherapie auf Radiochemosensibilisierung und Zellinvasion in-vitro und in-vivo analysiert.
Methodik: Zum Vergleich der Expression von JNK, beta1 Integrin und Kollagen Typ-I in GBM und Normalgewebe wurde eine Oncomine Datenbank Analyse durchgeführt. Das klonogene Überleben und die Invasion humaner GBM Zelllinien (U343-MG, T4), Stamm-ähnlicher (GS-8) und aus Patienten stammender GBM Zellen (DK32, DK42) wurden nach Bestrahlung (0-6 Gy Röntgen) in 2- und 3-dimensionaler Kollagen Typ-1 Matrix analysiert. Ergänzend dazu wurde eine Einzel- oder Doppelhemmung von beta1 Integrinen (AIIB2) und JNK (SP600125, siRNA) durchgeführt. Weiterhin wurden die Effekte einer Doppelhemmung in Kombination mit Radiochemotherapie auf Tumorwachstum und Überleben im orthotopen GBM Modell getestet. Veränderungen in der zugrundeliegenden zellulären Signaltransduktion (Phosphoproteomanalyse), Zellzyklus (FACS), DNA Schäden (53BP1 Foci) und Chromatinorganisation (Western Blot) wurden unter den genannten Behandlungsbedingungen evaluiert.
Ergebnisse: Oncomine Daten zeigen eine erhöhte Expression von beta1 Integrin und Kollagen Typ-I im GBM. Obwohl eine Einzelhemmung von beta1 Integrinen und JNK das Zellüberleben verringerte, führte nur eine Doppelhemmung beider Moleküle zur Strahlensensibilisierung und Invasionshemmung in allen getesteten GBM Zellpopulationen. Dieser Effekt basierte auf einer Adaptions-bedingten Erhöhung der beta1 Integrin Expression nach JNK Hemmung. Auch im orthotopen GBM Mausmodell führte ein beta1 Integrin/JNK Co-Targeting in Kombination mit Radiochemotherapie zu einer signifikanten Verzögerung des Tumorwachstums und einem längeren mittleren Überleben. Mechanistisch war dabei die Strahlensensibilisierung nach beta1 Integrin/JNK Hemmung auf eine erhöhte ATM Phosphorylierung und dem damit verbundenen G2/M Zellzyklusarrest zurückzuführen, der von einer erhöhten Anzahl an 53BP1 Foci und gesteigertem Euchromatingehalt begleitet wurde.
Schlussfolgerung: Unsere Daten zeigen, dass eine kombinierte beta1 Integrin/JNK Hemmung effizient die Radiochemoresistenz und Invasion von GBM Zellen verringert. Für eine Therapieoptimierung beim Glioblastom als auch bei anderen Malignomen birgt das Verständnis von Therapie-induzierten Adaptionsmechanismen ein großes Potenzial.
Keywords: GBM, Integrin, JNK, Radiochemoresistenz
  • Strahlentherapie und Onkologie 193(2017), S50-S51
  • Lecture (Conference)
    Jahrestagung der Deutsche Gesellschaft für Radioonkologie, 14.-18.06.2017, Berlin, Deutschland

Publ.-Id: 25183 - Permalink


beta1 integrin/JNK co-deactivation effectively targets adhesion- and stress-related adaptation radiochemoresistance in glioblastoma
Vehlow, A.; Klapproth, E.; Storch, K.; Dickreuter, E.; Seifert, M.; Dietrich, A.; Bütof, R.; Temme, A.; Cordes, N.;
Background: The poor prognosis of patients suffering from Glioblastoma multiforme (GBM) is mainly basedon therapy resistances of GBM stem- and tumor bulk cells and their invasive growth within the brain. Neglected are therapy-induced adaptation mechanisms. Here, we blocked bypass mechanisms simultaneously to radiochemotherapy by targeting the pro-survival beta1 integrins and the stress-related c-Jun N-terminal kinases (JNK) and evaluated the effectiveness of this strategy on GBM radiochemosensitization and invasion in vitro and in vivo.
Methods: An Oncomine database analysis was conducted to compare the expression of JNK, beta1 integrin and collagen type-I in GBM and brain. The clonogenic survival and the invasion of human GBM cell lines (U343-MG, T4), GBM stem-like (GS-8) and patient-derived cells (DK32, DK41) was quantified upon irradiation (0-6 Gy X-ray) in 2- and 3-dimensional collagen type-I matrix. On top of this treatment, beta1 integrins (AIIB2) and JNK (SP600125, siRNA) were inhibited in a single or dual manner. The effect of a combined beta1 integrin/JNK inhibition on tumor growth and survival was evaluated in orthotopic GBM mice treated with radiochemotherapy. Furthermore, underlying changes of cellular signaling cascades (phosphoproteome array), cell cycle (FACS), DNA damage (53BP1) and chromatin organization were evaluated upon beta1 integrin/JNK co-targeting.
Results: Oncomine data showed an increased expression of beta1 integrins and collagen type-I in GBM. While neither a single inhibition of beta1 integrins nor JNK reduced cell survival, co-targeting of both molecules induced radiosensitization and blocked cell invasion in all GBM cell populations tested. This treatment effect was promoted by an increased expression of pro-survival beta1 integrin upon JNK inhibition. Moreover, in combination with radiochemotherapy, beta1 integrin/JNK co-inhibition significantly delayed tumor growth in vivo leading to a significant longer survival of orthotopic GBM mice. Mechanistically, the radiosensitization upon beta1 integrin/JNK targeting was attributed to an amplified ATM phosphorylation and G2/M cell cycle arrest, which was accompanied by an increase in 53BP1 foci and euchromatin formation.
Conclusion: Our data show that a combined deactivation of beta1 integrin/JNK efficiently targets adaptation mechanisms and reduces GBM radiochemoresistance and invasion. Further understanding of therapy-induced bypass mechanisms is key for therapy optimization for GBM and other malignancies.
Keywords: GBM, integrin, JNK, radiochemoresistance
  • Contribution to proceedings
    Wolfsberg Meeting, 17.-19.06.2017, Ermatingen, Schweiz

Publ.-Id: 25182 - Permalink


beta1 integrins as novel co-regulators of DNA damage repair
Dickreuter, E.; Krause, M.; Borgmann, K.; Cordes, N.;
Introduction: Resistance to cancer therapies is a major unsolved challenge. One responsible factor is integrin-mediated adhesion to extracellular matrix. Several studies identified targeting of beta1 integrin receptors as promising approach for radio- and chemosensitization of tumor cells. Although different prosurvival beta1 integrin-mediated signaling pathways were identified, it remains unclear whether they are critically involved in the repair of radiation-induced DNA double strand breaks (DSB). Therefore, we examined the impact of beta1 integrin targeting on DSB repair and describe a regulatory function of beta1 integrins for DNA-PK-dependent but not PARP-dependent non-homologous end-joining (NHEJ).
Materials and methods: To mimic physiological growth conditions in vitro, a 3D cell culture model based on laminin-rich extracellular matrix and tumor xenografts of human head and neck squamous cell carcinoma (HNSCC) cell lines were employed. beta1 integrin targeting was accomplished using the inhibitory monoclonal antibody AIIB2. AIIB2, X-ray irradiation, siRNA-mediated knockdown and inhibitor treatment (FAK, JNK, DNA-PK, PARP) were performed and residual DSB number, NHEJ activity, expression and phosphorylation of various DNA repair proteins as well as clonogenic survival were determined.
Results and discussion: Intriguingly, beta1 integrin targeting impaired the repair of radiogenic DSB (gammaH2AX/p53BP1, pDNA-PKcs T2609 foci) in vitro and in vivo, decreased NHEJ activity and reduced expression and phosphorylation of Ku70, Rad50, Nbs1 and pDNA-PKcs T2609. Further, we identified Ku70, Ku80 and DNA-PKcs but not PARP-1 to reside in the beta1 integrin signaling pathway. It was compelling to observe an additive radiosensitization of 3D grown HNSCC cell lines by dual AIIB2/Olaparib treatment relative to monotherapies. Moreover, FAK and JNK1 were identified as mediators of beta1 integrin-dependent DNA repair.
Conclusion: Here, we support beta1 integrins as promising cancer targets and highlight a regulatory role for beta1 integrins in the DNA-PK-dependent repair of radiation-induced DSB. Further studies are needed to understand the relevance of cell adhesion for nuclear processes and cancer cell therapy resistance.
Keywords: HNSCC, DNA repair, Integrin
  • Contribution to proceedings
    19th International AEK Cancer Congress, 01.-03.03.2017, Heidelberg, Deutschland

Publ.-Id: 25181 - Permalink


Application of SPH Method for Sodium Fast Reactor Analysis
Rachamin, R.; Kliem, S.;
In this study, the capability of the DYN3D-Serpent codes system to simulate highly heterogeneous sodium-cooled fast systems was investigated. The BFS-73-1 critical assembly was chosen for the investigation. Initially, a 3D full model of the BFS-73-1 critical assembly was simulated using the Serpent Monte-Carlo (MC) code, and the basic neutronic characteristics were evaluated and compared against experimental values. This part meant as a first step towards the use of the Serpent MC code as a tool for preparation of homogenized group constants, and as a reference solution for code-to-code comparison with the DYN3D code. At the second part of the investigation, the BFS-73-1 critical assembly was modeled using the DYN3D code with few-group cross-sections generated by the Serpent MC code. It was suggested that for highly heterogeneous systems, such as the BFS experiments, the Superhomogenization (SPH) method should be applied to correct the few-group cross-sections of the different regions of the system. The SPH method is described and demonstrated for the BFS-73-1 critical assembly. It is shown that the application of the SPH method improves the accuracy of the DYN3D nodal diffusion solution, and therefore, it can be considered as a promising candidate of homogenization method for pin-by-pin calculations of sodium-cooled fast systems.
Keywords: SFR, BFS-73-1 experiment, Group constant generation, SPH, Serpent and DYN3D
  • Contribution to proceedings
    M&C 2017 - International Conference on Mathematics & Computational Methods Applied to Nuclear Science & Engineering, 16.-20.04.2017, Jeju, Korea
    Proceedings of M&C 2017
  • Lecture (Conference)
    M&C 2017 - International Conference on Mathematics & Computational Methods Applied to Nuclear Science & Engineering, 16.-20.04.2017, Jeju, Korea

Publ.-Id: 25179 - Permalink


Optimal sensor arrangement for Contactless Inductive Flow Tomography in the case of a Rayleigh-Benard convection
Wondrak, T.; Galindo, V.; Stefani, F.; Jacobs, R. T.;
The Contactless Inductive Flow Tomography is a procedure that enables the reconstruction of the global flow structure of an electrically conducting fluid by measuring the flow induced magnetic field outside the melt and subsequently solving the associated linear inverse problem. The accuracy of the reconstruction depends on the number and the distribution of the sensors around the vessel. The aim of this investigation is to find an optimal sensor configuration for a temperature driven flow of a liquid metal in a cylindrical vessel.
  • Lecture (Conference)
    18th International Symposium on Applied Electromagnetics and Mechanics (ISEM) 2017, 03.-6.9.2017, Chamonix, Frankreich
  • International Journal of Applied Electromagnetics and Mechanics 59(2019), 1291-1296
    DOI: 10.3233/JAE-171250

Publ.-Id: 25178 - Permalink


Determination of N* amplitudes from associated strangeness production in p+p collisions
Münzer, R.; Fabbietti, L.; Epple, E.; Lu, S.; Klose, P.; Hauenstein, F.; Herrmann, N.; Grzonka, D.; Leifels, Y.; Maggiora, M.; Pleiner, D.; Ramstein, B.; Ritman, J.; Roderburg, E.; Salabura, P.; Sarantsev, A.; Basrak, Z.; Buehler, P.; Cargnelli, M.; Caplar, R.; Czerwiakowa, O.; Deppner, I.; Dzelalija, M.; Fodor, Z.; Gasik, P.; Gasparic, I.; Grishkin, Y.; Hartmann, O. N.; Hildenbrand, K. D.; Hong, B.; Kang, T. I.; Kecskemeti, J.; Kim, Y. J.; Kirejczyk, M.; Kis, M.; Koczon, P.; Kotte, R.; Lebedev, A.; Le Fevre, A.; Liu, J. L.; Manko, V.; Marton, J.; Matulewicz, T.; Piasecki, K.; Rami, F.; Reischl, A.; Ryu, M. S.; Schmidt, P.; Seres, Z.; Sikora, B.; Sim, K. S.; Siwek-Wilczynska, K.; Smolyankin, V.; Suzuki, K.; Tyminski, Z.; Wagner, P.; Weber, I.; Widmann, E.; Wisniewski, K.; Xiao, Z. G.; Yamasaki, T.; Yushmanov, I.; Zhang, Y.; Zhilin, A.; Zinyuk, V.; Zmeskal, J.;
We present the first determination of the N* resonances excitation functions with masses between 1650 MeV/c² and 1900 MeV/c² by means of a combined Partial Wave Analysis of seven exclusively reconstructed data samples for the reaction p+p -> pK+Λ measured by the COSY-TOF, DISTO, FOPI and HADES collaborations in fixed target experiments at kinetic energies between 2.14 and 3.5 GeV.

Publ.-Id: 25177 - Permalink


On an Analog Controlled Precision Heat Power Source
Seilmayer, M.ORC; Katepally, V.ORC
The design of an analog controlled precision heat source is motivated by the measurement of the heat conductivity of liquids. In the framework of an online sensor which is able to measure physical properties like thermal conductivity or thermal diffusion in real time a precise and accurate heat source is required. Constant heat is applied to the material under test to acquire its different properties. Here, the common established methods of constant current or constant voltage may fail, because the heating resistor changes its resistance with temperature. The idea is to utilize a power monitor circuit like the LT2940, which contains an analog multiplier with a control loop around it. The initial design and its assumed uncertainties will be discussed. The first version of the power controller shows an outstanding performance in terms of precision in a steady state. Compared to conventional switching mode power sources the approach with an analog controlled heat source avoids EMI issues as well. The main goal of the present design is a precise heat source with less than 0.5% of error.
Keywords: precision heater, power control, analog controlled source

Publ.-Id: 25176 - Permalink


Open Access meets Saxony!
Reschke, E.ORC; Stöhr, M.; Kühle, G.
Die Open Access Tage 2017 werden in Dresden unter dem Dach von Dresden concept e.V. gemeinsam vom HZDR, der SLUB Dresden und der TU Dresden organisiert. Der Beitrag stellt die Veranstaltung vor.
Keywords: Open Access
  • Open Access LogoBIS : das Magazin der Bibliotheken in Sachsen 1(2017), 32-33

Downloads:

Publ.-Id: 25175 - Permalink


ESFR-SMART: new Horizon-2020 project on SFR safety
Mikityuk, K.; Girardi, E.; Krepel, J.; Bubelis, E.; Fridman, E.; Rineiski, A.; Girault, N.; Payot, F.; Buligins, L.; Gerbeth, G.; Chauvin, N.; Latge, C.; Garnier, J.-C.;
To improve the public acceptance of the future nuclear power in Europe we have to demonstrate that the new reactors have significantly higher safety level compared to traditional reactors. The ESFR-SMART project (European Sodium Fast Reactor Safety Measures Assessment and Research Tools) aims at enhancing further the safety of Generation-IV SFRs and in particular of the commercial-size European Sodium Fast Reactor (ESFR) in accordance with the European Sustainable Nuclear Industrial Initiative (ESNII) roadmap and in close cooperation with the Advanced Sodium Technological Reactor for Industrial Demonstration (ASTRID) program. The project aims at 5 specific objectives: 1) Produce new experimental data in order to support calibration and validation of the computational tools for each defence-in-depth level. 2) Test and qualify new instrumentations in order to support their utilization in the reactor protection system. 3) Perform further calibration and validation of the computational tools for each defence-in-depth level in order to support safety assessments of Generation-IV SFRs, using the data produced in the project as well as selected legacy data. 4) Select, implement and assess new safety measures for the commercial-size ESFR, using the GIF methodologies, the FP7 CP-ESFR project legacy, the calibrated and validated codes and being in accordance with the update of the European and international safety frameworks taking into account the Fukushima accident. 5) Strengthen and link together new networks, in particular, the network of the European sodium facilities and the network of the European students working on the SFR technology. Close interactions with the main European and international SFR stakeholders—Generation-IV International Forum (GIF), ASTRID Research and Development Cooperation
(ARDECo), ESNII and IAEA—via the Advisory Review Panel will enable reviews and recommendations on the project’s progress as well as dissemination of the new knowledge created by the project. By addressing the industry, policy makers and general public, the project is expected to make a meaningful impact on economics, environment, EU policy and society.
Keywords: Sodium fast reactor, safety, Horizon-2020
  • Contribution to proceedings
    International Conference on Fast Reactors and Related Fuel Cycles: Next Generation Nuclear Systems for Sustainable Development (FR17), 26.-29.06.2017, Yekaterinburg, Russian Federation
    Proceedings of the International Conference on Fast Reactors and Related Fuel Cycles

Publ.-Id: 25174 - Permalink


Objectives and Status of the OECD/NEA sub-group on Uncertainty Analysis in Modelling (UAM) for Design, Operation and Safety Analysis of SFRs (SFR-UAM)
Rimpault, G.; Buiron, L.; Stauff, N.; Kim, T.; Taiwo, T.; Lee, Y.; Aures, A.; Bostelmann, F.; Fridman, E.; Kereszturi, A.; Batki, B.; Kodeli, I.; Mikityuk, K.; Lopez, R.; Gomez, A.; Puente-Espel, F.; Del Valle, E.; Peregudov, A.; Semenov, M.; Manturov, G.; Nakahara, Y.; Dyrda, J.; Ivanova, T.;
An OECD/NEA sub-group on Uncertainty Analysis in Modelling (UAM) for Design, Operation and Safety Analysis of Sodium-cooled Fast Reactors (SFR-UAM) has been formed under the NSC/WPRS/EGUAM and is currently undertaking preliminary studies after having specified a series of benchmarks.
The incentive for launching the SFR-UAM task force comes from the desire to utilize current understanding of important phenomena to define and quantify the main core characteristics affecting safety and performance of SFRs. Best-estimate codes and data together with an evaluation of the uncertainties are required for that purpose, which challenges existing calculation methods. The group benefits from the results of a previous Sodium-cooled Fast Reactor core Feed-back and Transient response (SFR-FT) Task Force work under the
NSC/WPRS/EGRPANS.
Two SFR cores have been selected for the SFR-UAM benchmark, a 3600MWth oxide core and a 1000MWth metallic core. Their neutronic feedback coefficients are being calculated for transient analyses. The SFR-UAM sub-group is currently defining the grace period or the margin to melting available in the different accident scenarios and this within uncertainty margins. Recently, the work of the sub-group has been updated to incorporate new exercises, namely, a depletion benchmark, a control rod withdrawal benchmark, and the SUPER-PHENIX start-up transient. Experimental evidence in support of the studies is also being developed.
Keywords: SFR, uncertainties, OECD benchmark, reactivity coefficients
  • Contribution to proceedings
    International Conference on Fast Reactors and Related Fuel Cycles: Next Generation Nuclear Systems for Sustainable Development (FR17), 26.-29.06.2017, Yekaterinburg, Russian Federation
    Proceedings of the International Conference on Fast Reactors and Related Fuel Cycles

Publ.-Id: 25173 - Permalink


Evaluation of the OECD/NEA/SFR-UAM Neutronics Reactivity Feedback and Uncertainty Benchmarks
Stauff, N. E.; Kim, T. K.; Taiwo, T. A.; Buiron, L.; Rimpault, G.; Lee, Y.; Batki, B.; Keresztúri, A.; Bostelmann, F.; Zwermann, W.; Fridman, E.; Guilliard, N.; Lopez, R.; Gomez, A.; Puente-Espel, F.; Del Valle, E.; Peregudov, A.; Semenov, M.; Nakahara, Y.; Ivanova, T.; Gulliford, J.;
One of the tasks of the OECD/NEA sub-group on Uncertainty Analysis in Modeling (UAM) of Sodium-cooled Fast Reactors (SFR-UAM) under the NSC/WPRS/EGUAM is to perform a code-to-code comparison on neutronic feedback coefficients and associated uncertainties calculated for transient analyses. This benchmark exercise benefits from the results of a previous Sodium-cooled Fast Reactor core Feedback and Transient response (SFR-FT) Task Force work under the NSC/WPRS/EGRPANS. Two SFR cores have been selected for the SFR-UAM benchmark, the 3600MWth oxide and the 1000MWth metallic SFR cores.
Results from six and nine participating international institutes were received for respectively, the metallic and oxide SFR cores, using a wide range of calculation methodologies. The preliminary results display good agreement in the reactivity coefficients estimated, with remaining discrepancies explained by different nuclear data libraries, modeling approximations for deterministic solutions, and statistical convergence for stochastic evaluations on small perturbations. Nuclear data uncertainty evaluations for the reactivity coefficients from two institutions are compared and show consistent results.
Keywords: OECD Benchmark, SFR, Metallic fuel, Oxide fuel, feedback coefficient, uncertainty
  • Contribution to proceedings
    International Conference on Fast Reactors and Related Fuel Cycles: Next Generation Nuclear Systems for Sustainable Development (FR17), 26.-29.06.2017, Yekaterinburg, Russian Federation
    Proceedings of the International Conference on Fast Reactors and Related Fuel Cycles

Publ.-Id: 25172 - Permalink


Uncertainty Analysis of Kinetic Parameters for Design, Operation and Safety Analysis of SFRs
Kodeli, I.-A.; Rimpault, G.; Dufay, P.; Peneliau, Y.; Tommasi, J.; Fridman, E.; Zwermann, W.; Aures, A.; Ivanov, E.; Nakahara, Y.; Ivanova, T.; Gulliford, J.;
An OECD/NEA sub-group on Uncertainty Analysis in Best-Estimate Modelling (UAM) for Design, Operation and Safety Analysis of Sodium-cooled Fast Reactors (SFR-UAM) has been initiated in 2015 with the objective to study the uncertainties in different stages of Sodium Fast Reactors.
Best-estimate codes and data together with an evaluation of the uncertainties are required for that purpose, which challenges existing calculation methods. Neutronic status and reactivity feedback coefficients as well as the kinetic parameters are being calculated for transient analyses. Experimental evidence in support of the studies is also being developed.
The use of the Iterated Fission Probability method in the Monte Carlo codes such as Tripoli4® SERPENT-2 and MCNP-6 gives reference values for calculating βeff as well as Λeff and their uncertainties. Deterministic codes like ERANOS and PARTISN/SUSD3D are also used for nuclear data sensitivity analysis and uncertainty propagation. The computational approaches are tested using available integral experiments and the uncertainties of the measurements. A vast series of experiments has been selected and analysed leading to recommendations on the tools, procedures and data to be used for eff and/or transition functions calculating of the benchmarks including uncertainties.
Keywords: SFR, Beta-effective, Uncertainties
  • Contribution to proceedings
    International Conference on Fast Reactors and Related Fuel Cycles: Next Generation Nuclear Systems for Sustainable Development (FR17), 26.-29.06.2017, Yekaterinburg, Russian Federation
    Proceedings of the International Conference on Fast Reactors and Related Fuel Cycles

Publ.-Id: 25171 - Permalink


Comparison of two repository relevant archaea and their multistage bioassociation of uranium investigated with luminescence spectroscopy
Bader, M.; Swanson, J.; Drobot, B.; Steudtner, R.; Reed, D. T.; Stumpf, T.; Cherkouk, A.;
Microorganisms indigenous to rock salt must be considered for the safety analysis of a final repository for radioactive waste in a salt rock formation. Metabolic activity can cause microbial induced redox processes and influence radionuclide speciation and solubility. Additionally, passive biosorption onto living as well as dead biomass may affect the migration of radionuclides [1].
An extremely halophilic archaeon indigenous to rock salt was used for this study. Two similar strains with different origin were compared concerning their interaction processes with uranium. Halobacterium noricense DSM 15987 was originally isolated from an Austrian salt mine [2], the second strain Halobacterium putatively noricense was isolated from the Waste Isolation Pilot Plant (WIPP) [3].
[1] Lloyd, J. R. et al., Interactions of Microorganisms with Radionuclides (Eds. M. J. Keith-Roach, F. R. Livens), 313-342 (2002).
[2] Gruber, C. et al., Extremophiles, 8, Page 431-439 (2004).
[3] Swanson, J. S. et al., Status Report on the Microbial Characterization of Halite and Groundwater Samples from the WIPP - Status report Los Alamos National Laboratory, Page 1ff. (2012).
  • Lecture (Conference)
    ABC Salt V Actinide and Brine Chemistry in a Salt Repository Workshop (V), 26.-28.03.2017, Ruidoso, USA

Publ.-Id: 25170 - Permalink


Verification of the neutron diffusion code AZNHEX by means of the Serpent-DYN3D and Serpent-PARCS solution of the OECD/NEA SFR Benchmark
Torres, A. G.; Gallegos, E. D. V.; Ramirez Arriaga, L.; Lopez Solis, R. C.; Puente Espel, F.; Fridman, Emil; Kliem, S.;
AZNHEX is a neutron diffusion code for hexagonal-z geometry currently under development as part of the AZTLAN project in which a Mexican platform for nuclear core simulations is being developed. The diffusion solver is based on the RTN0 (Raviart-Thomas-Nédélec of index 0) nodal finite element method together with the Gordon-Hall transfinite interpolation which is used to convert, in the radial plane, each one of the four trapezoids in a hexagon to squares. The main objective of this work is to test the AZNHEX code capabilities against two well-known diffusion codes DYN3D and PARCS. In a previous work, the Serpent Monte Carlo code was used as a tool for preparation of homogenized group constants for the nodal diffusion analysis of a large U-Pu MOX fueled Sodium-cooled Fast Reactor (SFR) core specified in the OECD/WPRS neutronic SFR benchmark. The group constants generated by Serpent were employed by DYN3D and PARCS nodal diffusion codes in 3D full core calculations. A good agreement between the reference Monte Carlo and nodal diffusion results was reported demonstrating the feasibility of using Serpent as a group constant generator for the deterministic SFR analysis. In order to verify the under development solver inside AZNHEX, the same Serpent generated cross sections sets for each material were exported to AZNHEX format for four different states (as in DYN3D and PARCS): a) a reference case in which the multiplication factor (keff) is the compared value, b) the Doppler constant (KD), c) the sodium void worth, and d) the total control rod worth. Additionally, the radial power distribution was also calculated. The results calculated with AZNHEX showed also a quite good agreement in the direct comparison with DYN3D (-66 pcm in keff) and PARCS (-109 pcm in keff) and therefore against the Serpent reference solution (-194 pcm in keff). As AZNHEX is still under development further improvements will be implemented and new tests will be carried out, but so far the results presented here give confidence in the development.
  • Contribution to proceedings
    International Conference on Fast Reactors and Related Fuel Cycles: Next Generation Nuclear Systems for Sustainable Development (FR17), 26.-29.06.2017, Yekaterinburg, Russian Federation
    Proceedings of the International Conference on Fast Reactors and Related Fuel Cycles

Publ.-Id: 25169 - Permalink


Modeling of Phenix End-of-Life control rod withdrawal tests with the Serpent-DYN3D code system
Nikitin, E.; Fridman, E.;
The nodal diffusion code DYN3D is under extension for Sodium cooled Fast Reactor (SFR) applications. As a part of the extension a new model for axial thermal expansion of fuel rods was developed. The model provides a flexible way of handling the axial fuel rod expansion that is each sub-assembly and node can be treated independently. In the current paper the new model will be described in details. The performance of the model will be assessed with the help of the benchmark on the control rod withdrawal tests performed during the PHÉNIX end-of-life experiments. The DYN3D results will be tested against the experimental data as well as against the numerical results provided by other participants to the benchmark.
Keywords: SFR, DYN3D, Serpent, Thermal expansion
  • Contribution to proceedings
    International Conference on Fast Reactors and Related Fuel Cycles: Next Generation Nuclear Systems for Sustainable Development (FR17), 26.-29.06.2017, Yekaterinburg, Russian Federation
    Proceedings of the International Conference on Fast Reactors and Related Fuel Cycles

Publ.-Id: 25168 - Permalink


A new look at the structural and magnetic properties of potassium neptunate K2NpO4 combining XRD, XANES spectroscopy and low temperature heat capacity
Smith, A. L.; Colineau, E.; Griveau, J.-C.; Kauric, G.; Martin, P.; Scheinost, A. C.; Cheetham, A. K.; Konings, R. J. M.;
The physico-chemical properties of the potassium neptunate K2NpO4 have been investigated in this work using X-ray diffraction, X-ray Absorption Near Edge Structure (XANES) spectroscopy at the Np-L3 edge, and low temperature heat capacity measurements. A Rietveld refinement of the crystal structure is reported for the first time. The Np(VI) valence state has been confirmed by the XANES data, and the absorption edge threshold of the XANES spectrum has been correlated to the Mossbauer isomer shift value reported in the literature. The standard entropy and heat capacity of K2NpO4 have been derived at 298.15 K from the low temperature heat capacity data. The latter suggest the existence of a magnetic ordering transition around 25.9 K, most probably of the ferromagnetic type.
Keywords: Potassium neptunate, X-ray diffraction, XANES, Calorimetry

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Publ.-Id: 25167 - Permalink


Bioassociation of uranium onto extreme halophilic microorganisms relevant in nuclear waste repositories in rock salt
Bader, M.; Swanson, J.; Foerstendorf, H.; Müller, K.; Cherkouk, A.;
For the final storage of radioactive waste in a deep geological formation rock salt is a potential host rock. Indigenous microorganisms and its interactions with radionuclides have to be considered for the safety performance of the repository in terms of a worst case scenario, where radionuclides are potentially released from the storage site. Therefore, two extreme halophilic microorganisms, which originally occur in rock salt, were used to study its interactions with uranium. The kinetics of uranium bioassociation onto cells of the extreme halophilic archaeon Halobacterium noricense DSM 15987 and the moderate halophilic bacterium Brachybacterium sp. G1 were investigated in detail in batch experiments. For the understanding on a molecular level, in situ infrared spectroscopy was applied, monitoring the bioassociation processes online.
It turned out, that the mechanism of uranium association onto the two different microorganisms differs. The studies were performed at 1.7 M NaCl and 3 M NaCl for the bacterium and archaeon, respectively, to keep the essential osmotic pressure. Both experiments started with washed cells from the exponential growth phase at an initial U(VI) concentration of 40 µM U(VI) at pCH+ 6 (corrected pH due to the presence of high chloride concentration). The occurring process for Brachybacterium sp. G1 was a fast biosorption process, which was completed after 1 h. Infrared spectroscopy showed that only carboxylate functional groups were involved in uranium sorption. In contrast, the association onto H. noricense was a rather complex, multistage process [1]. Within the first hour, an association was observed, which was followed by a desorption phase for about 4 hours. Subsequently, uranium was bioassociated again over the timeframe of one week. Apart from carboxylate functional groups, contributions of phosphoryl groups to uranium binding were evidenced by infrared spectroscopy. The occurrence of the multistage uranium association was furthermore visualized with scanning electron microscopy.
[1] Bader, M et al. (2017) J. Hazard. Mater. 32, 225 – 232.
  • Lecture (Conference)
    6th International Symposium on Biosorption and Biodegradation/Bioremediation - BioBio 2017, 25.-29.06.2017, Prague, Czech Republik

Publ.-Id: 25166 - Permalink


Explicit decay heat calculation in the nodal diffusion code DYN3D
Bilodid, Y.ORC; Fridman, E.ORC; Kotlyar, D.ORC; Shwageraus, E.ORC
3D reactor dynamic code DYN3D was developed for analysis of transients and accident scenarios. The residual radioactive decay heat plays an important role in some of accident scenarios and in DYN3D it is taken into account by a model based on German national standard DIN Norm 25463. The applicability of this model is limited to a low enriched uranium dioxide fuel for light water reactors.
This paper describes the new general decay heat model implemented in DYN3D. The radioactive decay rate of each nuclide in each spatial node is calculated and the cumulative released heat is used to obtain the decay power spatial distribution for any time step. Such explicit approach is based on first principles and is free from approximations which limit its applicability. The proposed method is verified against Monte Carlo reference calculations.
Keywords: decay heat, DYN3D, microdepletion
  • Contribution to proceedings
    M&C 2017 - International Conference on Mathematics & Computational Methods Applied to Nuclear Science & Engineering, 16.-20.04.2017, Jeju, Korea
  • Lecture (Conference)
    M&C 2017 - International Conference on Mathematics & Computational Methods Applied to Nuclear Science & Engineering 2017, 16.-20.04.2017, Jeju, Korea

Publ.-Id: 25165 - Permalink


Computational modelling of flashing flows: a literature survey
Liao, Y.; Lucas, D.;
A review of published work on the physics and modelling of flashing flows is presented. The term “flashing” refers to a familiar phase change phenomenon initiated by pressure drop. It has gained a great deal of attention due to various industrial safety concerns. Nevertheless, knowledge about the involved physical processes such as formation and growth of bubbles in superheated liquid, and information for appropriate modelling in practical systems is still far from sufficiency. The present work is aimed to provide a brief but comprehensive overview of available theoretical models for these sub-phenomena as well as general modelling frameworks. This kind of review is necessary and helpful for further understanding and investigation of flashing flows in more detail.
Keywords: flashing flow; nucleation; coalescence and breakup; two-fluid model; poly-disperse

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Publ.-Id: 25164 - Permalink


3D matrix-based cell cultures: Automated analysis of tumor cell survival and proliferation
Eke, I.; Hehlgans, S.; Sandfort, V.; Cordes, N.;
Three-dimensional ex vivo cell cultures mimic physiological in vivo growth conditions thereby significantly contributing to our understanding of tumor cell growth and survival, therapy resistance and identification of novel potent cancer targets. In the present study, we describe advanced three-dimensional cell culture methodology for investigating cellular survival and proliferation in human carcinoma cells after cancer therapy including molecular therapeutics. Single cells are embedded into laminin-rich extracellular matrix and can be treated with cytotoxic drugs, ionizing or UV radiation or any other substance of interest when consolidated and approximating in vivo morphology. Subsequently, cells are allowed to grow for automated determination of clonogenic survival (colony number) or proliferation (colony size). The entire protocol of 3D cell plating takes ~1 h working time and pursues for ~7 days before evaluation. This newly developed method broadens the spectrum of exploration of malignant tumors and other diseases and enables the obtainment of more reliable data on cancer treatment efficacy.

Publ.-Id: 25162 - Permalink


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