Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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36093 Publications

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

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.


Publ.-Id: 25187

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) ( 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
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

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

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

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

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

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

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

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
    Online First (2018) DOI: 10.3233/JAE-171250

Publ.-Id: 25178

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

On an Analog Controlled Precision Heat Power Source

Seilmayer, M.; Katepally, V.

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

Open Access meets Saxony!

Reschke, E.; 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 Logo BIS : das Magazin der Bibliotheken in Sachsen 1(2017), 32-33


Publ.-Id: 25175

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

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
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

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

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

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

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

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

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


Publ.-Id: 25167

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

Explicit decay heat calculation in the nodal diffusion code DYN3D

Bilodid, Y.; Fridman, E.; Kotlyar, D.; Shwageraus, E.

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

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


Publ.-Id: 25164

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

Comparison of toxicity and outcome in stage III NSCLC patients treated with IMRT or VMAT

Wijsman, R.; Dankers, F.; Troost, E. G. C.; Hoffmann, A. L.; Bussink, J.

  • Abstract in refereed journal
    Radiotherapy and Oncology 119(2016)Suppl.1, S317

Publ.-Id: 25161

beta1 Integrin/JNK Wechselwirkung im Glioblastom: Radiochemosensibilisierung und Invasionshemmung

Vehlow, A.; Klapproth, E.; Storch, K.; Matzke, D.; Cordes, N.

  • Abstract in refereed journal
    Strahlentherapie und Onkologie 192(2016)Suppl.1, 75

Publ.-Id: 25160

The potential of radiomics for radiotherapy individualization

Troost, E. G. C.; Pilz, K.; Löck, S.; Leger, S.; Richter, C.

Publ.-Id: 25159

Three-dimensional ECM-based cell culture models for cancer research

Storch, K.; Dickreuter, E.; Vehlow, A.; Cordes, N.

  • Abstract in refereed journal
    European Journal of Cancer 61(2016)Suppl.1, S74

Publ.-Id: 25158

Gene signatures predict loco-regional control after postoperative radiochemotherapy in HNSCC

Schmidt, S.; Linge, A.; Lohaus, F.; Gudziol, V.; Nowak, A.; Tinhofer, I.; Budach, V.; Sak, A.; Stuschke, M.; Balermpas, P.; Rödel, C.; Avlar, M.; Grosu, A. L.; Abdollahi, A.; Debus, J.; Belka, C.; Pigorsch, S.; Combs, S. E.; Mönnich, D.; Zips, D.; Baretton, G. B.; Buchholz, F.; Baumann, M.; Krause, M.; Löck, S.

Publ.-Id: 25157

MRI imaging of irradiated liver tissue for in vivo verification in particle therapy

Richter, C.; Duda, D. G.; Guimaraes, A. R.; Hong, T. S.; Bortfeld, T. R.; Seco, J.

  • Abstract in refereed journal
    Radiotherapy and Oncology 119(2016)Suppl.1, S51-S52

Publ.-Id: 25156

The variability of the RBE in proton therapy: can we base it on empirical clinical data?

Lühr, A.; von Neubeck, C.; Baumann, M.; Krause, M.

  • Abstract in refereed journal
    Radiotherapy and Oncology 119(2016)Suppl. 1, S417

Publ.-Id: 25155

Instrumentation for Experiments on a Fuel Element Mock-Up for the study of Thermal Hydraulics for Loss of Cooling or Coolant Scenarios in Spent Fuel Pools

Arlit, M.; Partmann, C.; Schleicher, E.; Schuster, C.; Hurtado, A.; Hampel, U.

Beside the nuclear reactor and its primary circuit the spent fuel pool is yet another safety-critical part in a nuclear power plant which has gained increasing focus after the Fukushima accident. Loss of coolant or enduring loss of cooling conditions would ultimately result in loss of cladding integrity at elevated temperatures with excessive release of fission products and hydrogen. To predict the available response time and to assess the efficacy of mitigating measures computer simulations can be employed. Their validity, however, needs to be proven by dedicated experiments at lower scale but relevant thermal hydraulic conditions. For that purpose, the test facility ALADIN was designed, which enables conduction of experiments on a single BWR fuel element mock-up under loss of coolant and loss of cooling accident conditions. In this paper we introduce the facility and its instrumentation, with a focus on temperature sensors and a new thermal anemometry grid sensor for spatially resolved flow velocity measurement of the superheated steam in the subchannels together with the affiliated calibration procedure.

Keywords: Spent fuel pool; temperature measurement; thermal anemometry; grid sensor

Publ.-Id: 25154

Modeling and fitting mineral microstructures by multinary random fields

Teichmann, J.; Menzel, P.; Heinig, T.; van den Boogaart, K. G.

Modeling mineral microstructures is of high importance in geostatistics in order to render realistic geological patterns. An appropriate model should be applicable to varying microstructures and account for correlations within the facies, i.e., the shape and size of the grains as well as for dependencies between the facies, e.g., facies A lies within facies B, or facies A and B are not connected. This allows to simulate the geometry of a microstructure in combination with other microstructural properties like mineralogy, crystall lattice orientation, (locally varying) chemical composition, inclusions, grain boundaries, subgrain boundaries and defects.

The common plurigaussian method, a valuable approach in geostatistics, can account for correlations within each facies and in principle be extended to correlations between the facies. Founded on particular case of this model, formulas for first- and second-order characteristics, such as volume fraction, correlation function and cross-correlation function can be given by a multivariate normal distribution, which makes model fitting more feasible. Based on first- and second-order statistics which can easily
be estimated by convolution, model fitting requires only numerical inversion of several one-dimensional monotone functions in this model.

The applicability is demonstrated for the two-dimensional case by modeling the microstructure
from a Mineral Liberation Analyzer image data set and evaluated by a deviation test.

  • Contribution to proceedings
    18th Annual Conference IAMG 2017, 02.09.2017, Perth, Australia

Publ.-Id: 25153

Uniaxial ferromagnetism of local uranium moments in hexagonal UBeGe

Gumeniuk, R.; Yaresko, A. N.; Schnelle, W.; Nicklas, M.; Kvashnina, K. O.; Hennig, C.; Grin, Y.; Leithe-Jasper, A.

The new intermetallic uranium beryllium germanide UBeGe and its thorium analogon ThBeGe crystallize with the hexagonal ZrBeSi type of structure. Studies of magnetic, thermal, and transport properties were performed on polycrystalline samples between 1.8 and 750K. UBeGe is a uniaxial ferromagnet and there are indications for two magnetic transitions at Tc(1) ≈ 160K and Tc(2) ≈ 150K. The high paramagnetic effective moment μeff ≈ 3 1μB, x-ray absorption near-edge spectroscopy (XANES, 17–300 K), as well as theoretical DFT calculations indicate localized U 5f2 states in UBeGe. ThBeGe is a diamagnetic metallic material with low density of states at the Fermi level.

Keywords: ThBeGe; PXRD; HEFD XANES; electrical resistivity

Publ.-Id: 25152

Experimental Studies on high-pressure high-temperature Contact-Condensation at falling jets in the TOPFLOW Pressure-Tank

Seidel, T.; Beyer, M.; Lucas, D.; Hampel, U.

We report on generic experimental studies dealing with the direct contact condensation of steam at a falling sub-cooled water jet at high pressure and temperature. This generic problem concerns some safety-relevant thermal hydraulic scenarios in light water reactors. One of such is the question for heat transfer and mixing when a sub-cooled jet of water in an emergency core-cooling scenario enters a hot pressurized component of the primary reactor circuit. The involved phenomena of heat transfer are complex in this case, reaching from direct condensation of steam via steam bubble entrainment to single phase mixing of hot and cold water.
Experiments were performed in the TOPFLOW pressure tank, which is an experimental facility for high-pressure thermal hydraulics experiments in pressure equilibrium. The facility has been designed for studying steam-water two-phase flows at pressures of up to 50 bar. It enables to run experiments in flow domains of complex shape without high difference pressures across the wall. The concept therefore allows us to use thin metal walls and even glass windows to observe flows in complex geometry domains with the help of IR or video camera and to considerably reduce cost and complexity of experimental installations.

Keywords: Direct contact condensation; falling jet; pressurized two-phase flow; high-speed videometry; pressure tank technology

Publ.-Id: 25151

Impact of tumour hypoxia and cancer stem cells on loco-regional control after primary radiochemotherapy in locally advanced HNSCC – results of a multicentre biomarker study of the German Cancer Consortium radiation Oncology Group

Linge, A.; Lohaus, F.; Löck, S.; Gudziol, V.; Nowak, A.; von Neubeck, C.; Tinhofer, I.; Budach, V.; Sak, A.; Stuschke, M.; Balermpas, P.; Rödel, C.; Avlar, M.; Grosu, A. L.; Abdollahi, A.; Debus, J.; Bayer, C.; Belka, C.; Pigorsch, S.; Combs, S. E.; Mönnich, D.; Zips, D.; Baretton, G. B.; Buchholz, F.; Baumann, M.; Krause, M.

  • Abstract in refereed journal
    Oncology Research and Treatment 39(2016)Suppl.1, 22-23

Publ.-Id: 25150

Tumour volume, hypoxia and cancer stem cells as prognosticators for LRC after primary RCT in HNSCC

Linge, A.; Lohaus, F.; Löck, S.; Gudziol, V.; Nowak, A.; von Neubeck, C.; Tinhofer, I.; Budach, V.; Sak, A.; Stuschke, M.; Balermpas, P.; Rödel, C.; Avlar, M.; Grosu, A. L.; Abdollahi, A.; Debus, J.; Belka, C.; Pigorsch, S.; Combs, S. E.; Mönnich, D.; Zips, D.; Baretton, G. B.; Buchholz, F.; Baumann, M.; Krause, M.

Publ.-Id: 25149

Fullerene Derivatives as Nano-Additives in Polymer Composites

Penkova, A. V.; Acquah, S. F. A.; Piotrovskiy, L. B.; Markelov, D.; Semisalova, A.; Kroto, H. W.

Since their discovery, fullerenes have become one of the most recognizable molecules in science. The “beautiful molecule” described by Sir Harold Kroto has been subtly referenced in movie, and has adorned the covers of many science-based textbooks. The physical and chemical properties of fullerenes have generated a lot of interest in the science community with many opportunities to develop new avenues for scientific research. However, the difficulties in the commercial use of fullerenes, such as C60, have likely been due to issues with solubility. Fortunately, the situation has improved over the last decade with research into fullerene derivatives. Once modified, fullerenes may have applications in a variety of areas, including medicine, drug delivery, optoelectronics, and electrochemistry. The addition of low concentrations of carbon nanoparticles to polymer matrices may result in significant changes in the function of polymer-based composite materials.
This review will highlight the applications of fullerene derivatives as nano-additives for polymer composites. In this review, fullerene derivatives, such as water-soluble carbon nanoclusters (hydroxyl and carboxyl groups), and hydrophobic fullerenes, such as metallofullerenes and methanofullerenes, will be evaluated in regards to their potential impact on commercial applications, such as photovoltaic devices, fuel cells, membrane technology and biocompatible electroactive actuators.

Keywords: Fullerene; photovoltaic; sensor; antioxidant; catalyst

Publ.-Id: 25148

Comparison of machine-learning methods for predictive radiomic models in locally advanced HNSCC

Leger, S.; Bandurska-Luque, A.; Pilz, K.; Zöphel, K.; Baumann, M.; Troost, E. G. C.; Löck, S.; Richter, C.

Publ.-Id: 25147

Hypoxie und Krebsstammzellmarker als Biomarker für die Radio(chemo)therapie von Kopf-Hals Plattenepithelkarzinomen

Krenn, C.; Linge, A.; Lohaus, F.; Löck, S.; Baumann, M.; Krause, M.

  • Abstract in refereed journal
    Strahlentherapie und Onkologie 192(2016)Suppl.1, 121-122

Publ.-Id: 25146

beta1-Integrin/c-Abl Interaktion reguliert DNA Reparatur und Strahlensensibilität humaner Tumorzellen

Koppenhagen, P.; Dickreuter, E.; Cordes, N.

  • Abstract in refereed journal
    Strahlentherapie und Onkologie 192(2016)Suppl.1, 39

Publ.-Id: 25145

Discoidin Domain Receptor 1 targeting impairs GBM cell invasion and mediates radiochemosensitization by induction of autophagy

Klapproth, E.; Vehlow, A.; Cordes, N.

  • Abstract in refereed journal
    European Journal of Cancer 61(2016)Suppl.1, S160-S161

Publ.-Id: 25144

DDR1 reguliert Radiochemosensitivität sowie Invasivität humaner Glioblastomzellen

Klapproth, E.; Vehlow, A.; Cordes, N.

  • Abstract in refereed journal
    Strahlentherapie und Onkologie 192(2016)Suppl.1, 42-43

Publ.-Id: 25143

A Bayesian network model for acute dysphagia prediction in NSCLC patients

Jochems, A. T. C.; Deist, T. M.; Troost, E. G. C.; Dekker, A.; Faivre-Finn, C.; Oberije-Dehing, C.; Lambin, P.

  • Abstract in refereed journal
    Radiotherapy and Oncology 119(2016)Suppl.1, S118-S119

Publ.-Id: 25142

Re-Mining - Ressourcen aus Bergbauhalden

Büttner, P.; Gutzmer, J.

Beitrag zum Tagungsband zur Veranstaltung "Economic Governance und Ordonomik 2016", welche in Halle im Festsaals des Siedehauses des Technischen Halloren- und Salinemuseums stattgefunden hat und auf der die Ergbnisse zum Projekt SMSB (Re-Mining) in einem Vortrag präsentiert wurden.

Keywords: Re-Mining; Halden; Tailings; Ressourcentechnologie; Resource; Rohstoffe; 3D-Model; GOCAD; Exploration; Processing; Aufbereitung; Erzgebirge; Tiefenbachhalde; Spülhalde; Davidschacht; Zero waste

  • Book chapter
    in: Economic Governance und Ordonomik: Die Nutzung von Ressourcen - mehr als eine ökonomische Fragestellung, Halle-Wittenberg: SPEEG, 2016, 978-3-86829-870-3, 213-225

Publ.-Id: 25141

Targeting of beta1 integrins compromises DNA damage repair for radiosensitization of head and neck cancer cells

Dickreuter, E.; Eke, I.; Krause, M.; Borgmann, K.; van Vugt, M.; Cordes, N.

  • Abstract in refereed journal
    European Journal of Cancer 61(2016)Suppl.1, S1

Publ.-Id: 25140

Integration of 7T MRI into image-guided radiotherapy of glioblastoma: a feasibility study

Compter, I.; Peerlings, J.; Eekers, D. B. P.; Postma, A. A.; Ivanov, D.; Wiggins, C.; Kubben, P.; Küsters, B.; Wesseling, P.; Ackermans, L.; Schijns, O. E. M. G.; Lambin, P.; Hoffmann, A. L.

  • Abstract in refereed journal
    Radiotherapy and Oncology 119(2016)Suppl.1, S867-S868

Publ.-Id: 25139

Re-Mining – Gewinnung strategischer Metalle und anderer Mineralien aus sächsischen Bergbauhalden

Büttner, P.; Gutzmer, J.

Ein wichtiges Ziel des SMSB Projektes war es Technologien für eine möglichst effiziente und wirtschaftliche Aufbereitung strategischer Metalle und Mineralien aus Bergbauhalden mit besonders hohem Rohstoffpotential zu entwickeln. Dafür wurden verschiedene Ansätze gewählt. Es Zunächst wurde das beinhaltete Rohstoffpotential ausgewählter Haldenkörper durch Bohrungen und umfassende mineralogische und chemische Analytik konkretisiert. Dann wurden Versuche zur chemischen und biologischen Laugung an Haldenmaterial durchgeführt, aber auch moderne mechanische Aufbereitungsverfahren auf ihre Anwendbarkeit getestet. Mithilfe der nachgeschalteten Metallurgie wurden die gewonnenen Konzentrate weiter untersucht und Metalle aus diesen extrahiert. Auf die Versuche und Ergebnisse zur Aufbereitung sowie der Metallurgie wird in diesem Beitrag nicht näher eingegangen. Die Ergebnisse sind im SMSB Abschlussbericht zu finden. Aus den Resultaten von SMSB wurde ein Kataster der zwanzig bedeutendsten sächsischen Bergbauhalden erstellt. Diese Informationen wurden gemeinsam mit den Ergebnissen von zwei weiteren r³-Projekten, den Projekten ROBEHA mit Fokus Harz und ReStrateGIS mit Fokus Saarland, Ruhrgebiet und Thüringen zusammengeführt. Dabei wurde ein gemeinsames Haldenkataster erzeugt. Weiterhin wurden die Methoden zur Charakterisierung, Erkundung und Aufbereitung der Halden zusammengetragen und in einem gemeinsamen Methodenhandbuch zusammengestellt. Einige dieser Ergebnisse werden in diesem Beitrag vorgestellt.

Keywords: Re-Mining; Halden; Tailings; Ressourcentechnologie; Resource; Rohstoffe; 3D-Model; GOCAD; Exploration; Processing; Aufbereitung; Erzgebirge; Tiefenbachhalde; Spülhalde; Davidschacht

  • Book chapter
    in: Mineralische Nebenprodukte und Abfälle, Band 3, Berlin: TK Verlag Karl J. Thomé-Kozmiensky, 2016, 978-3-944310-28-2, 383-393
  • Invited lecture (Conferences)
    Berliner Konferenz mineralische Nebenprodukte und Abfälle, 20.-21.06.2016, Berlin, Germany
  • Invited lecture (Conferences)
    1st Workshop Goiano de Terras Raras, 23.-25.05.2016, Catalao, Brasil
  • Invited lecture (Conferences)
    EIT Raw Materials Brookerage Event "ReMining and process residues", 18.-19.01.2016, Berlin, Germany
  • Invited lecture (Conferences)
    Economic Governance und Ordonomik: Die Nutzung von Ressourcen - mehr als eine ökonomische Fragestellung, 17.-19.02.2016, Halle, Germany

Publ.-Id: 25138

SMSB - Gewinnung strategischer Metalle und Mineralien aus sächsischen Bergbauhalden

Büttner, P.; Osbahr, I.; Luhmer, R.; Pilz, C.; Uhlig, S.; Leißner, T.; Pätzold, C.; Scheel, M.; Jahns, C.; Martin, M.; Gutzmer, J.

Projektbericht über das Projekt SMSB - Gewinnung strategischer Metalle und Mineralien aus sächsischen Bergbauhalden. Das Projekt SMSB hatte zum Ziel, die zwanzig größten Metallerzbergbauhalden Sachsens zu erfassen und in einem Kataster zusammenzufügen. Die Davidschachthalde in Freiberg und die Tiefenbachhalde in Altenberg wurden als zwei Flotations-Rückstandshalden mit besonders hohem Wertstoffpotenzial identifiziert durch jeweils 10 Bohrungen im Detail erkundet. Aus den Bohrkernen wurden insgesamt 207 Proben entnommen und ihr Stoffbestand mit verschiedenen chemischen und mineralogischen Analyseverfahren quantifiziert. Weiterhin wurden an dem gewonnen Probenmaterial verschiedene Aufbereitungsverfahren im Labormaßstab getestet. Diese Versuche hatten das Ziel, geeignete Technologien für das Abtrennen von Wertstoffen aus dem Haldenmaterial zu identifizieren. Resultate belegen, dass sich die Tiefenbachhalde insbesondere durch hohe Gehalte an Zinn, die Davidschachthalde dagegen durch hohe Konzentrationen von Indium, Blei und Zink auszeichnen. Das Zinn in der Tiefenbachhalde ist durch ein einziges Oxidmineral (Kassiterit) vertreten, während die Wertstoffe in der Davidschachthalde an eine komplexe Vergesellschaftung von Sulfiden gebunden sind. Arsen – in der Form von Arsenopyrit – ist das einzige wesentliche Schadelement in dem Material der Tiefenbachhalde. In den Rückständen der Davidschachthalde dagegen sind die Schadstoffe Arsen und Cadmium sehr eng mit den Wertstoffen assoziiert, oft vertreten in den gleichen Erzmineralien. Aufbereitungstests belegen, dass Wert- und Schadstoffe aus der Spülhalde Davidschacht sehr effizient durch biologische Laugung mobilisiert und entfernt werden können, für die Tiefenbachhalde wurde dagegen die Flotation als geeignete Aufbereitungstechnologie identifiziert.Anhand der gewonnenen Daten und erzielten Versuchsergebnisse wurden für die beiden Halden dreidimensionale Ressourcenpotenzial-Modelle erstellt, die auf Kombinationen von gewichteten aufbereitungsrelevanten Parametern fußen. Die einzelnen Parameter haben einen Einfluss darauf, wie effizient eine gewählte Aufbereitungstechnologie auf das vorhandene Haldenmaterial wirken kann.

Keywords: Re-Mining; SMSB; Resource; Freiberg; Tailings; Processing; GOCAD; 3D-Model; INTRA r³+; Resource Technology; Halden; Tiefenbachhalde; Spülhalde; Davidschacht; Aufbereitung; Exploration

  • Book chapter
    in: Innovative Technologien für Ressourceneffizienz - Strategische Metalle und Mineralien, Stuttgart: Fraunhofer Verlag, 2016, 978-8396-1102-9, 345-360

Publ.-Id: 25137

Biomarker für die individualisierte Strahlentherapie

Linge, A.; Lohaus, F.; Löck, S.; Krause, M.; Baumann, M.

  • Book chapter
    Karl-Jürgen Wolf, Wolfram Knapp, Thomas Herrmann: Strahlenforschung in der Medizin – Relevanz und Perspektiven, Nova Acta Leopoldina - Neue Folge Band 121 Nummer 406, Stuttgart: Wissenschaftliche Verlagsgesellschaft, 2016, 333-344

Publ.-Id: 25136

The Role of Cancer Stem Cells in Tumour Radioresponse

Linge, A.; Dubrovska, A.; Baumann, M.; Krause, M.

  • Book chapter
    Anscher, M.S., Valerie, K.: Strategies to Enhance the Therapeutic Ratio of Radiation as a Cancer Treatment, Switzerland: Springer International Publishing, 2016, 43-74

Publ.-Id: 25135

FMISO as a Biomarker for Clinical Radiation Oncology

Zschaeck, S.; Steinbach, J.; Troost, E. G. C.

  • Book chapter
    Baumann, M.; Krause, M.; Cordes, N.: Molecular Radio-Oncology, Volume 198 of the series Recent results in Cancer Research,, Berlin Heidelberg: Springer Verlag, 2016, 189-201


Publ.-Id: 25134

Ambidextrous Idea Generation-Antecedents and Outcomes

Gurtner, S.; Reinhardt, R.

Ambidexterity, defined as the capability to develop both incremental and radical innovations, is an important driver of firm success. Idea generation is an essential starting point for both types of innovation. Therefore, this study investigates whether ambidextrous idea generation, defined as the capability to actively generate both incremental and radical ideas, affects new product development (NPD) success. Analyses on the Comparative Performance Assessment Study (CPAS) data, which includes data from 453 companies distributed over 24 countries, demonstrate that ambidextrous idea generation does indeed affect NPD program success. Consequently, this study also investigates which antecedents foster ambidextrous idea generation. The innovation paradox concept predicts that achieving ambidexterity requires overcoming paradoxical antecedents. Therefore, we tested whether combinations of financial and breakthrough orientations (the paradox of strategic emphasis), a formal innovation process and an innovation culture (the paradox of innovation drivers), tight and loose customer coupling (the paradox of customer orientation), and internal development and external collaboration (the paradox of openness) affects ambidextrous idea generation. The results show that only customer orientation and openness have the expected inverted u-shaped effect. These finding are in line with construal level theory, which predicts that the organizational characteristics that influence idea-generation activity must be at the same construal level to have the desired effect. The contribution of this study is twofold. First, the analyses indicate that ambidextrous idea generation has significant repercussions for the entire NPD program. Second, the results show that resolving innovation paradoxes only has an effect if the construal level of the paradox and the activity match. This finding indicates an important boundary condition for the innovation paradox concept.

Publ.-Id: 25133

Fate of Plutonium Released from a Former Nuclear Weapons Test in Australia

Ikeda-Ohno, A.; Mokhber-Shahin, L.; Howard, D. L.; Collins, R. N.; Payne, T. E.; Johansen, M. P.

A series of the British nuclear weapons tests conducted between 1953 and 1963 at the southeast area of the Great Victoria Desert, South Australia (Fig. 1(a)), dispersed long-lived and radioactive nuclear debris including plutonium (Pu). A reliable assessment of the environmental impact of these radioactive contaminants and their potential implications for human health requires an understanding of their physical/chemical characteristics at the molecular scale. This study focuses on the physical/chemical characterisation of the Pu contaminant, the most problematic radioactive contaminant remaining at the former testing sites, by synchrotron-based X-ray microscopy / spectroscopy.
The Pu legacy samples investigated in this study were collected at one of the former testing sites, the Taranaki site at Maralinga (Fig. 1(b)). The collected soil samples were physically sieved several times and further fractionated by heavy liquid density separation to isolate a small particle with significantly high radioactivity. The isolated particles were then transported to the X-ray fluorescence microscopy (XFM) beamline at the Australian Synchrotron. The X-ray fluorescence mapping indicates that the particle forms an inhomogeneous core-shell structure composed of a concentrated Pu core coated by the external layer containing Ca, Fe and U.1 This suggests that most of the Pu within the particle is currently unavailable for interaction with the environment, but the bioavailability of Pu could be potentially increased in the future when the particle morphology is further changed by the surface weathers. These findings also highlight the importance of the comprehensive characterization of radioactive contaminants for reliable environmental- and radiotoxicological assessment.

Keywords: actinides; plutonium; environmental radioactivity; radioactive contaminants; nuclear weapons tests; X-ray fluorescence microscopy; X-ray absorption spectroscopy; synchrotron

  • Lecture (Conference)
    Actinides 2017, 10.-14.07.2017, Sendai, Japan

Publ.-Id: 25132

Targeted next-generation sequencing of locally advanced squamous cell carcinomas of the head and neck reveals druggable targets for improving adjuvant chemoradiation

Tinhofer, I.; Budach, V.; Saki, M.; Konschak, R.; Niehr, F.; Jöhrens, K.; Weichert, W.; Linge, A.; Lohaus, F.; Krause, M.; Neumann, K.; Endris, V.; Sak, A.; Stuschke, M.; Balermpas, P.; Rödel, C.; Avlar, M.; Grosu, A. L.; Abdollahi, A.; Debus, J.; Belka, C.; Pigorsch, S.; Combs, S. E.; Mönnich, D.; Zips, D.; Baumann, M.; DKTK-ROG

Despite clear differences in clinical presentation and outcome, squamous cell carcinomas of the head and neck (SCCHN) arising from human papilloma virus (HPV) infection or heavy tobacco/alcohol consumption are treated equally. Next-generation sequencing is expected to reveal novel targets for more individualised treatment.

Patients and methods
Tumour specimens from 208 patients with locally advanced squamous cell carcinoma of the hypopharynx, oropharynx or oral cavity, all uniformly treated with adjuvant cisplatin-based chemoradiation, were included. A customised panel covering 211 exons from 45 genes frequently altered in SCCHN was used for detection of non-synonymous point and frameshift mutations. Mutations were correlated with HPV status and treatment outcome.

Mutational profiles and HPV status were successfully established for 179 cases. HPV– tumours showed an increased frequency of alterations in tumour suppressor genes compared to HPV+ cases (TP53 67% versus 4%, CDKN2A 18% versus 0%). Conversely, HPV+ carcinomas were enriched for activating mutations in driver genes compared to HPV– cases (PIK3CA 30% versus 12%, KRAS 6% versus 1%, and NRAS 4% versus 0%). Hotspot TP53 missense mutations in HPV– carcinomas correlated with an increased risk of locoregional recurrence (hazard ratio [HR] 4.3, 95% confidence interval [CI] 1.5–12.1, P = 0.006) and death (HR 2.2, 95% CI 1.1–4.4, P = 0.021). In HPV+ SCCHN, driver gene mutations were associated per trend with a higher risk of death (HR 3.9, 95% CI 0.7–21.1, P = 0.11).

Distinct mutation profiles in HPV– and HPV+ SCCHN identify subgroups with poor outcome after adjuvant chemoradiation. Mutant p53 and the phosphoinositide 3-kinase pathway were identified as potential druggable targets for subgroup-specific treatment optimisation.

Keywords: Head and neck cancer; Human papilloma virus; Mutation profiles; Adjuvant chemoradiation; Cisplatin

Publ.-Id: 25131

A Compton camera prototype for prompt gamma medical imaging

Thirolf, P. G.; Aldawood, S.; Böhmer, M.; Bortfeldt, J.; Castelhano, I.; Dedes, G.; Fiedler, F.; Gernhäuser, R.; Golnik, C.; Helmbrecht, S.; Hueso-González, F.; von D. Kolff, H.; Kormoll, T.; Lang, C.; Liprandi, S.; Lutter, R.; Marinšek, T.; Maier, L.; Pausch, G.; Petzoldt, J.; Römer, K.; Schaart, D.; Parodi, K.

Compton camera prototype for a position-sensitive detection of prompt γ rays from proton-induced nuclear reactions is being developed in Garching. The detector system allows to track the Comptonscattered electrons. The camera consists of a monolithic LaBr3:Ce scintillation absorber crystal, read out by a multi-anode PMT, preceded by a stacked array of 6 double-sided silicon strip detectors acting as scatterers. The LaBr3:Ce crystal has been characterized with radioactive sources. Online commissioning measurements were performed with a pulsed deuteron beam at the Garching Tandem accelerator and with a clinical proton beam at the OncoRay facility in Dresden. The determination of the interaction point of the photons in the monolithic crystal was investigated.

Publ.-Id: 25130

The impact of CDK9 on radiosensitivity, DNA damage repair and cell cycling of HNSCC cancer cells

Storch, K.; Cordes, N.

Cyclin-dependent kinase 9 (CDK9), mainly involved in regulation of transcription, has recently been shown to impact on cell cycling and DNA repair. Despite the fact that CDK9 has been proposed as potential cancer target, it remains largely elusive whether CDK9 targeting alters tumor cell radiosensitivity. Five human head and neck squamous cell carcinoma (HNSCC) cell lines (SAS, FaDu, HSC4, Cal33, UTSCC5) as well as SAS cells stably transfected with CDK9-EGFP-N1 plasmid or empty vector controls were used. Upon either CDK9 small interfering RNA knockdown or treatment with a pan-CDK inhibitor (ZK304709), colony formation, DNA double strand breaks (DSBs), apoptosis, cell cycling, and expression and phosphorylation of major cell cycle and DNA damage repair proteins were examined. While CDK9 overexpression mediated radioprotection, CDK9 depletion clearly enhanced the radiosensitivity of HNSCC cells without an induction of apoptosis. While the cell cycle and cell cycle proteins were significantly modulated by CDK9 depletion, no further alterations in these parameters were observed after combined CDK9 knockdown with irradiation. ZK304709 showed concentration-dependent cytotoxicity but failed to radiosensitize HNSCC cells. Our findings suggest a potential role of CDK9 in the radiation response of HNSCC cells. Additional studies are warranted to clarify the usefulness to target CDK9 in the clinic.

Publ.-Id: 25129

ESTRO consensus guideline on target volume delineation for elective radiation therapy of early stage breast cancer, version 1.1.

Offersen, B. V.; Boersma, L. J.; Kirkove, C.; Hol, S.; Aznar, M. C.; Sola, A. B.; Kirova, Y. M.; Pignol, J.-P.; Remouchamps, V.; Verhoeven, K.; Weltens, C.; Arenas, M.; Gabrys, D.; Kopek, N.; Krause, M.; Lundstedt, D.; Marinko, T.; Montero, A.; Yarnold, J.; Poortmans, P.

Publ.-Id: 25128

Independent validation of the prognostic value of cancer stem cell marker expression and hypoxia-induced gene expression for patients with locally advanced HNSCC after postoperative radiotherapy

Linge, A.; Löck, S.; Krenn, C.; Appold, S.; Lohaus, F.; Nowak, A.; Gudziol, V.; Baretton, G. B.; Buchholz, F.; Baumann, M.; Krause, M.


To validate the impact of HPV status, cancer stem cell (CSC) marker expression and tumour hypoxia status in patients with locally advanced head and neck squamous cell carcinoma (HNSCC), who received postoperative radiotherapy. The results of the exploration cohort have previously been reported by the German Cancer Consortium Radiation Oncology Group (DKTK-ROG; Lohaus et al., 2014; Linge et al., 2016).

Materials and methods

For 152 patients with locally advanced HNSCC the impact of HPV16 DNA status, CSC marker expression and hypoxia-associated gene signatures on outcome of postoperative radiotherapy were retrospectively analysed. Out of them, 40 patients received postoperative radiochemotherapy. Cox models presented in a previous study were validated using the concordance index as a performance measure. The primary endpoint of this study was loco-regional control. Results were compared to those previously reported by DKTK-ROG.


Loco-regional control, freedom from distant metastases and overall survival were inferior to the previously reported cohort. Despite of this, the prognostic value of the combination of HPV infection status, CSC marker expression (SLC3A2) and tumour hypoxia status could be validated in univariate analyses using an independent validation cohort. For multivariate models, the concordance index was between 0.58 and 0.69 in validation, indicating a good prognostic performance of the models. The inclusion of CD44 and the 15-gene hypoxia signature moderately improved the performance compared to a baseline model without CSC markers or hypoxia classifiers.


The HPV status, CSC marker expression of CD44 and SLC3A2 as well as hypoxia status are potential prognostic biomarkers for patients with locally advanced HNSCC treated by postoperative radiotherapy.

Keywords: Biomarker; Cancer stem cells; HNSCC; HPV; Hypoxia; Postoperative radiochemotherapy; Validation

Publ.-Id: 25127

Clinical trials for personalized glioblastoma radiotherapy: Markers for efficacy and late toxicity but often delayed treatment – Does that matter?

Lattermann, A.; Baumann, M.; Krause, M.

Publ.-Id: 25126

Targeting of β1 integrins impairs DNA repair for radiosensitization of head and neck cancer cells

Dickreuter, E.; Eke, I.; Krause, M.; Borgmann, K.; van Vugt, M. A.; Cordes, N.

β1 Integrin-mediated cell–extracellular matrix interactions allow cancer cell survival and confer therapy resistance. It was shown that inhibition of β1 integrins sensitizes cells to radiotherapy. Here, we examined the impact of β1 integrin targeting on the repair of radiation-induced DNA double-strand breaks (DSBs). β1 Integrin inhibition was accomplished using the monoclonal antibody AIIB2 and experiments were performed in three-dimensional cell cultures and tumor xenografts of human head and neck squamous cell carcinoma (HNSCC) cell lines. AIIB2, X-ray irradiation, small interfering RNA-mediated knockdown and Olaparib treatment were performed and residual DSB number, protein and gene expression, non-homologous end joining (NHEJ) activity as well as clonogenic survival were determined. β1 Integrin targeting impaired repair of radiogenic DSB (γH2AX/53BP1, pDNA-PKcs T2609 foci) in vitro and in vivo and reduced the protein expression of Ku70, Rad50 and Nbs1. Further, we identified Ku70, Ku80 and DNA-PKcs but not poly(ADP-ribose) polymerase (PARP)-1 to reside in the β1 integrin pathway. Intriguingly, combined inhibition of β1 integrin and PARP using Olaparib was significantly more effective than either treatment alone in non-irradiated and irradiated HNSCC cells. Here, we support β1 integrins as potential cancer targets and highlight a regulatory role for β1 integrins in the repair of radiogenic DNA damage via classical NHEJ. Further, the data suggest combined targeting of β1 integrin and PARP as promising approach for radiosensitization of HNSCC.

Publ.-Id: 25125

Bridging the valley of death: The new Radiotherapy & Oncology section “First in man - Translational innovations in radiation oncology.”

Baumann, M.; Overgaard, J.

Publ.-Id: 25124

Potential modeling with uncertain covariables

Schaeben, H.; Tolosana Delgado, R.; van den Boogaart, K. G.

Published potential mapping procedures usually presume that the covariables are known.
However, covariables are usually interpolated by kriging. In sparsely covered regions reported covariables can seriously differ from the actual situation on the ground. When regressing to the mean we often nd the variation of covariables underestimated, leading to an overestimation of dependence. Similar effects can be observed when the fitted model is applied to prediction: The potential seems promising, but is underestimated in sparsely observed regions.
In earlier publications it has been shown that a Cox regression model is more general than weights of evidence methods, and also independent of a grid with a user defined resolution.
Therefore our investigation is based on this model class. Here we compare four different estimation procedures for Cox regression models: (i) the pseudolikelihood method put forward by Baddeley, (ii) a numerical solution of the full Maximum Likelihood approach based on kriged covariables, (iii) an approximation of the full Maximum Likelihood approach based on the conditional distribution of the covariables, and (iv) the MCMC based Bayesian solution.
The first two methods neglect the uncertainty of the covariables, the latter two account for it. For simulated examples with known true parameters we can show a substantial decrease of estimation errors when the uncertainty is considered.
It can be shown that the estimation error reported by the methods neglecting the uncertainty of covariables seriously underestimates the actual uncertainty of the parameter estimate.

Keywords: Exploration; Potential Modelling; Metropolis Hastings; Markov Chain Monte Carlo Method for geostatistical data

  • Lecture (Conference)
    18th Annual Conference IAMG2017, 03.-09.09.2017, Perth, Australia

Publ.-Id: 25123

Model based multiple point statistics and training model estimation

van den Boogaart, K. G.; Tolosana Delgado, R.; Ortiz, J.

We would like to put the workflows of two point geostats and multi point geostatistics in a common framework of model estimation, model selection, algorithmic parameter selection and than finally simulation and prediction. This workflow is well established in to point geostats. In this contribution we extend it to multi point geostatistics. In this way we can improve the performance by better choices for the all method parameters.
Two point geostatistics typically puts three decisions ahead of each estimation or simulation: Based on the observations we choose a variogram model, estimate its parameters, and select a kriging neighbourhood to weigh between computational speed and algorithmic accuracy.
For Multiple Point statistics simulation methods we typically provide all knowledge about the spatial dependence by a fixed training image. Three different ways for generating training images have been proposed: Real maps or 3D models of the phenomenon, constructed images capturing our knowledge, and realisations of random field models. The random field model used for the simulation could be understood as our model of the distribution of the random field we would like to interpolate. The simulation of the training image and the following multiple point simulation is an imperfect numerical algorithm computing the conditional distribution based on that model. Just like two point geostatistics it again has the patterns as algorithmic parameters describing a geostatistical neighbourhood.
Like with variogram models, for any more complicated random fields models, we have model parameters. Depending on them different sets of observations will have different likelihoods. I.e. like with classical variogram estimation we can estimate the model parameters from the observations. As the likelihoods are typically not computable and variogram based methods can only capture two point dependences, we propose a quasilikelihood based multi point approach for the estimation of these parameters. Analog to variogram model comparison we also propose cross validation based methods to check the fit of the model and the performance of the simulation algorithm on the model. In analogy to the selection of search neighbourhood the simulation performance of the algorithm can be checked against the model.

Keywords: Nonlinear Geostatistics; Training models; Training Images; Parameter Estimation

  • Contribution to proceedings
    18th Annual Conference IAMG2017, 03.-09.09.2017, Perth, Australia
    Proceedings of IAMG2017

Publ.-Id: 25122

Block Predictions of Compositional Data with high order geostatistics

Tolosana Delgado, R.; Talebi, H.; Mueller, U.; van den Boogaart, K. G.

Block kriging of compositional data is a challenge even in the case of classical linear statistics. Compositional kriging is not unbiased with respect to the quantity used additively in block integration. Classical block kriging can leave the compositional simplex. Compositional data cannot directly be integrated in a block, when the material density varies within the block. For full compositions the density might be a function of the composition. For subcomposition it is typically still correlated. In a previous publication we developed a geostatistical block prediction of compositional data relying on the additive lognormal property of the compositional random field. This assumption is however not always met. Especially in case of multiple facies, we see bimodal distributions leading to substantially different distribution of block values. Due to the non lognormality of the residuals typical lognormal kriging type bias corrections are not appropriate.
For this situation we propose to apply conditional distribution based type of multiple point geostatistics. Based on a training image or a training model, we generate joint dataset of the observations of the block integral value incorporating all relevant corrections (like density correction). The conditional distribution is described by a very general version of a generalized linear model for the conditional distribution. The parameters of this regression model are estimated from the training dataset. Compositional, Euclidean expected values can be computed from the resulting prediction.
The method has the following properties: The Expected difference of true value and prediction is 0. The method provides the full conditional distribution. Not only the mean, but more selected nonlinear functionals can be predict on average correct from the conditional distribution. Due to its underlying Baysian nature the method can in principle outperform averages over conditional simulations with mps or ordinary kriging.

Keywords: Block Kriging; Conditional Distribution; Geostatistik

  • Lecture (Conference)
    18th Annual Conference of the International Association for Mathematical Geoscience - IAMG 2017, 03.-09.09.2017, Perth, Australia

Publ.-Id: 25121

Shining light on the beauty of f-electron systems: principles and perspectives of X-ray spectroscopy

Kvashnina, K. O.

Investigations of the electronic structure of different systems have been the subject of continuous research efforts over the last 100 years. Parallel to the technical developments and experimental discoveries, the theoretical models, describing the observed phenomena, have advanced. The challenges arise in the studies of exotic systems, where the most extraordinary behaviors need to be understood in detail. To improve our understanding, we search for the most extreme experimental methods, testing strange combinations of theoretical approximations; there are still many questions that remain unknown. This is the case of f-electron systems.

The aim of this HDR thesis is to demonstrate the applicability of X-ray spectroscopy for determining the electronic structure of f-electron systems, and to show the importance of theoretical simulations in understanding the experimental results. Special attention has been paid to the high-energy resolution fluorescence detection (HERFD) X-ray absorption near edge structure (XANES), X-ray emission spectroscopy (XES) and resonant inelastic X-ray scattering (RIXS) methods. It is shown here that a combination of high-quality experimental data and theoretical calculations can provide unprecedented detailed information about the electronic structure of actinide and lanthanide systems

  • Other
    Univerisite Grenoble Alpes (UGA), 2017
    Mentor: Andreas Scheinost

Publ.-Id: 25120

Resonant x-ray spectroscopy of uranium intermetallics at the U M4,5 edges

Kvashnina, K. O.; Walker, H. C.; Magnani, N.; Lander, G. H.; Caciuffo, R.

We present resonant x-ray emission spectroscopic (RXES) data from the uranium intermetallics UPd3, USb, USn3 and URu2Si2 at the U M4,5 edges and compare the data to those from the well-localized 5f2 semiconductor UO2. The technique is especially sensitive to any oxidation of the surface, and this was found on the USb sample, thus preventing a good comparison with a material known to be 5f3. 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 resonant inelastic x-ray scattering (RIXS) provides information on the U P3 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.


Publ.-Id: 25118

Polyphenols delivery by polymeric materials: challenges in cancer treatment.

Vittorio, O.; Curcio, M.; Cojoc, M.; Goya, G.; Hampel, S.; Iemma, F.; Dubrovska, A.; Cirillo, G.

Nanotechnology can offer different solutions for enhancing the therapeutic efficiency of polyphenols, a class of natural products widely explored for a potential applicability for the treatment of different diseases including cancer. While possessing interesting anticancer properties, polyphenols suffer from low stability and unfavorable pharmacokinetics, and thus suitable carriers are required when planning a therapeutic protocol. In the present review, an overview of the different strategies based on polymeric materials is presented, with the aim to highlight the strengths and the weaknesses of each approach and offer a platform of ideas for researchers working in the field.

Keywords: Nanocarrier; polyphenols; cancer therapy; polymeric materials

Publ.-Id: 25117

Nanoparticles for radiooncology: Mission, vision, challenges.

Kunz-Schughart, L.; Dubrovska, A.; Peitzsch, C.; Ewe, A.; Aigner, A.; Schellenburg, S.; Muders, M.; Hampel, S.; Cirillo, G.; Iemmae, F.; Tietze, R.; Alexiou, C.; Stephan, H.; Zarschlerg, K.; Vittorio, O.; Kavallaris, M.; Parak, W.; Mädler, L.; Pokhrel, S.

Cancer is one of the leading non-communicable diseases with highest mortality rates worldwide. About half of all cancer patients receive radiation treatment in the course of their disease. However, treatment outcome and curative potential of radiotherapy is often impeded by genetically and/or environmentally driven mechanisms of tumor radioresistance and normal tissue radiotoxicity. While nanomedicine-based tools for imaging, dosimetry and treatment are potential keys to the improvement of therapeutic efficacy and reducing side effects, radiotherapy is an established technique to eradicate the tumor cells. In order to progress the introduction of nanoparticles in radiooncology, due to the highly interdisciplinary nature, expertise in chemistry, radiobiology and translational research is needed. In this report recent insights and promising policies to design nanotechnology-based therapeutics for tumor radiosensitization will be discussed. An attempt is made to cover the entire field from preclinical development to clinical studies. Hence, this report illustrates (1) the radio- and tumor-biological rationales for combining nanostructures with radiotherapy, (2) tumor-site targeting strategies and mechanisms of cellular uptake, (3) biological response hypotheses for new nanomaterials of interest, and (4) challenges to translate the research findings into clinical trials.

Keywords: Flame spray pyrolysis; Magnetic particles; Nanoparticles; Radiooncology; Radiosensitizers; Radiotherapy


Publ.-Id: 25116

Epigenetic targeting therapy for tumor radiosensitization

Schniewind, I.; Peitzsch, C.; von Neubeck, C.; Baumann, M.; Krause, M.; Dubrovska, A.

Introduction: A malignant tumor is composed of a hierarchically organized, heterogeneous pool of cells in various stages of differentiation including cancer stem cells (CSCs) as the main cell population responsible for tumor initiation, growth and relapse as well as for metastasis formation and therapy resistance. Preliminary work of our group showed that photon irradiation of prostate cancer cells induces an augmentation of the CSC population that can be attributed to an epigenetic reprogramming of non-CSCs into CSCs. The combination of the histone methyltransferase EZH2 inhibitor 3-Deazaneplanocin A (DZNep) with x-ray irradiation leads to a radiosensitization and prevention of the cellular reprogramming of prostate cancer cells in vitro, in vivo and in ex vivo treated primary prostate cancer samples.

Objectives: The aim of this study is (1) the investigation of potential radiosensitizing effects of epigenetic inhibitors for different tumor entities including prostate cancer, head and neck squamous cell carcinoma (HNSCC) and glioblastoma multiforme (GBM); (2) a high throughput screening (HTS) using a chemical library with epigenetic targeting substances to identify novel epigenetic targeting agents for tumor radiosensitization and (3) the correlation of radiation-induced CSC and epigenetic markers after photon versus 150MeV proton irradiation to identify biomarkers for a personalized proton therapy.

Methods: Evaluation of the cytotoxicity (MTT-Assay, CellTiterGlo®-Assay), radiosensitivity (colony formation assay), DNA repair capacity (γH2AX foci assay), CSC marker expression (Flow cytometry) and histone modifications (Western blot) for prostate cancer (DU145, PC3), HNSCC (FaDu, Cal33) and GBM (LN229, U87MG) cell lines using different clinically relevant epigenetic modulators in combination with irradiation.

Results: Our results show that epigenetic marks including histone modifications are modulated after ionizing radiation in the different tumor entities including prostate cancer, HNSCC and GBM and that treatment with some epigenetic inhibitors leads to the radiosensitization of cancer cells. Furthermore, we found differences in CSC marker expression and epigenetic modulation after photon versus proton irradiation.

Conclusion: Epigenetic targeting therapy may be useful as a co-therapy strategy to prevent tumor cell reprogramming and promote radiosensitization of the different tumor entities. Moreover, CSC and histone mark-based biomarkers can be potentially used as predictive markers for a personalized radiotherapy.

Keywords: epigenetics; radioresistance; DNA repair

  • Contribution to proceedings
    23. DEGRO-Jahrestagung 2017, 15.-18.02.2017, Berlin, Deutschland
    Strahlentherapie und Onkologie 193, S182
  • Abstract in refereed journal
    Strahlentherapie und Onkologie 193(2017), S182-S183
    DOI: 10.1007/s00066-017-1137-6

Publ.-Id: 25115

CD98hc a potential biomarker for therapy outcome and a putative therapeutical target for radiosensitization of head and neck squamous cell carcinoma

Digomann, D.; Kurth, I.; Linge, A.; Hein, L.; Heiden, S.; Baumann, M.; Dubrovska, A.

Retrospective analyses of CSC-related biomarkers followed by prospective validation studies in patients with locally advanced HNSCC are currently being performed in an ongoing multicentre retrospective – prospective trial conducted by the Radiation Oncology Group of the German Cancer Consortium (DKTK-ROG) For the patients with locally advanced head and neck squamous cell carcinoma (HNSCC) treated with a curatively intended cisplatin-based postoperative radiochemotherapy or primary radiochemotherapy, the expression level of SLC3A2 (Solute Carrier Family 3 member 2), a putative cancer stem cell marker was positively correlated with poor locoregional control in locally advanced (HNSCC) [1, 2].
The human gene SLC3A2 encodes the heavy chain of CD98; a ~125 kDa heterodimeric L-type amino acid transporter. CD98hc also interacts with integrin β subunit and has a putative role in regulating integrin signaling, which controls cell proliferation, survival, migration, and epithelial adhesion [3].
The aim of this study is to elucidate the potential role of stem cell marker CD98hc in regulation of the HNSCC radiosensitivity.
The expression levels of CD98 in nine HNSCC cell lines measured by western blot analysis and flow cytometry were positively correlated with their respective in vivo tumor control dose 50 (TCD50) values (ref). An increase of CD98hc expression was also detected by Western blotting in the radioresistant derivatives of the established HNSCC cells as compared to their parental counterparts. In addition, expression of CD98hs was induced in the parental HNSCC cells after single dose irradiation of HNSCC cells with 4Gy of X-ray.
To analyze a functional role of CD98hc in the regulation of HNSCC radioresistance, SLC3A2 (gene of CD98hc) was knocked down via siRNA in Cal33, Fadu, UT5 and SAS cells, which then were subjected to the radiobiological colony formation assays. A knockdown of SLC3A2 in HNSCC cells followed by irradiation decreased the capability for colony formation compared to the cells transfected with scrambled siRNA.
For further in vitro and in vivo experiments, cell lines with a low CD98hc level were established using CRISPR/Cas9 technology. Off-targets were reduced using a modified CRISPR/Cas9-variant that was confirmed by PCR and sequencing experiments.
In addition, a recombinant neutralizing antibody against CD98hc is currently tested as possible CD98hc targeted and radiosensitizing therapy.
Finally, publicly available TCGA-gene dataset for HNSCC patients treated with and without radiotherapy was used to analyze a potential correlation of SLC3A2 expression with expression of other genes and clinical outcome of the HNSCC patients.
The results support the hypothesis that CD98hc is playing a role in the regulation of HNSCC radioresistance. In the future CD98hc may be used as a prognostic marker and become a potential target for combined radiochemotherapy in locally advanced HNSCC.

[1] Linge, A., Lock, S., Gudziol, V., Nowak, A., Lohaus, F., von Neubeck, C., Jutz, M., Abdollahi, A.,
Debus, J., Tinhofer, I., et al. (2016). Low CSC marker expression and low hypoxia identify good
prognosis subgroups in HPV(-)HNSCC after postoperative radiochemotherapy: a multicenter study
of the DKTK-ROG. Clin. Cancer Res.
[3]Cantor, J.M., Ginsberg, M.H., 2012. CD98 at the crossroads of adaptive immunity and cancer. J Cell Sci 125, 1373–1382. doi:10.1242/jcs.096040

Keywords: CD98; HNSCC; Radioresistance

  • Contribution to proceedings
    DEGRO Akademie: 26. Symposium Experimentelle Strahlentherapie und Klinische Strahlenbiologie, 09.-11.02.2017, Universitätsklinikum Tübingen, Deutschland
  • Abstract in refereed journal
    Strahlentherapie und Onkologie 192(2016)Suppl.1, 124

Publ.-Id: 25114

CD98hc as a potential marker of radioresistance in head and neck squamous cell carcinoma

Digomann, D.; Kurth, I.; Linge, A.; Löck, S.; Koi, L.; Hein, L.; Heiden, S.; Krause, M.; Baumann, M.; Dubrovska, A.

Background: CD98hc protein is encoded by the SLC3A2 (solute carrier family 3 member 2) gene. CD98hc contributes to the amino acid transport and regulation of the integrin signaling pathway, and is a putative marker of cancer stem cells (CSCs). Recent retrospective analyses showed a correlation of high SLC3A2 expression with poor locoregional control in patients with locally advanced head and neck squamous cell carcinoma (HNSCC) treated with a curatively intended cisplatin-based postoperative radiochemotherapy or primary radiochemotherapy. The aim of this study is the investigation of potential molecular mechanisms of action of CD98hc as a regulator of HNSCC radioresistance. Methods: The expression levels of CD98 in nine HNSCC cell lines were measured by Western blot analysis and correlated with corresponding tumor control dose 50 (TCD50) values. The fractions of plasma membrane proteins from Cal33 and FaDu cells and their radioresistant sublines established by fractionated irradiation with a total dose of ≥50Gy of X-rays were enriched by differential centrifugation and quantitatively analyzed by tandem mass spectrometry. To determine the role of SLC3A2 in the regulation of cell radioresistance, HNSCC cell lines and their respective irradiated sublines were transfected with SLC3A2 siRNAs and analysed by 2D and/or 3D radiobiological clonogenic assays after X-ray irradiation. The CRISPR/Cas9 system was used for the stable monoallelic knock-out of SLC3A2 in HNSCC cells. The efficiency of DNA repair after irradiation was examined by γH2A.X foci analysis. The Cancer Genome Atlas (TCGA) gene dataset for HNSCC patients treated with and without radiotherapy was used to analyse a potential correlation of SLC3A2 expression with expression of other genes and with clinical outcome of the HNSCC patients. Results and Discussion: The data of proteomic profiling, the results of Western blot analysis correlated to TCD50 values, the functional assessment of the SLC3A2 knockdown and knockout cells along with analysis of the TCGA datasets confirmed a connection between the CD98hc expression level and the cancer cell radiosensitivity in vitro and in vivo. These results support the hypothesis that CD98hc is a regulator of HNSCC radioresistance. The ongoing experimental studies will reveal if CD98hc may be used as potential target for HNSCC radiosensitization.

Keywords: CD98; HNSCC; radioresistance

  • Contribution to proceedings
    The 15th International Wolfsberg Meeting on Molecular Radiation Biology/Oncology, 17.-19.06.2017, CH-8272 Ermatingen, Switzerland

Publ.-Id: 25113

Interaktion von Stammzelleigenschaften und DNA Reparatur bestimmen die strahlensensitivierende Wirkung nach Inhibition von CHK1, RAD51 und PARP1 in TNBCs

Meyer, F.; Becker, S.; Niecke, A.; Werner, S.; Peitzsch, C.; Hein, L.; Dubrovska, A.; Goy, Y.; Parplys, A.; Petersen, C.; Riepen, B.; Zielinski, A.; Rothkamm, K.; Borgmann, K.

Fragestellung: Das Mammakarzinom fasst eine heterogene Gruppe von Tumoren zusammen von denen etwa 20% als Triple-negativ (TNBC) bezüglich des Rezeptorstatus bezeichnet werden. Wichtige Parameter und therapeutische Angriffspunkte der TNBC Biologie sind eine hohe Proliferationsaktivität, ein Basal-artiger und mesenchymaler Phänotyp und ein Defekt im DNA Reparaturweg Homologe Rekombination (HR) welcher eine erhöhte chromosomale Instabilität dieser Tumore begünstigt. TNBCs weisen darüber hinaus eine Anreicherung von Tumorstammzellen und Therapieresistenz auf. Ziel des Projektes ist es Strategien unter gleichzeitiger Ausnutzung von HR-Defizienz und Stammzelleigenschaften durch spezifische Inhibition zur Intensivierung der Therapie weiter zu entwickeln. Dies wurde für die Inhibition von RAD51-, CHK1- und PARP1 nach Bestrahlung untersucht. Dafür wurde eine TNBC-Zelllinie (MDA-231 WT), zwei isogenen Sublinien, die präferentiell in Knochen (-SA) und Gehirn (-BR) metastasieren im Vergleich zu einer luminalen Zelllinie (MCF7) eingesetzt.
Methodik: In MDA-MB-231 WT/BR/SA und MCF7-Zellen wurde die Expression bezüglich HR (RAD51, BRCA1, PTEN, CHK1, MRE11, ATR, ATM) und Stammzelleigenschaften (ZEB1, E-Cadherin, ß-Catenin, ALDH1) charakterisiert, HR mittels RAD51-Foci, MMC-Sensitivität und Reporterplasmiden eingeordnet, Replikationsprozesse analysiert und die Migrationsfähigkeit überprüft. Strahlenempfindlichkeit wurde unter Gabe verschiedener Inhibitoren im Kolonietest dokumentiert und mit der Metabric Datenbank (952 TNBC) hinsichtlich des chromosomalen Instabilitätsindex (CIN) korreliert.
Ergebnisse: Es zeigten sich klare Unterschiede in der Expression von Reparaturproteinen, mit einem Anstieg von CHK1, MRE11 und ATM in BR und SA. Beide Linien zeigten Stammzell-übliche Expressionsprofile, entsprechend eine stärkere Migrationsfähigkeit und in der SA Linie eine verbesserte HR (2,5-fach), Resistenz gegen MMC (IC50 von 1,6µg/ml im Vergleich zu 0,75µg/ml in BR und 2,1 µg/ml in SA) und geringere DNA Schäden (0,75-fach). Nach Bestrahlung zeigte sich kein Überlebensvorteil für BR und SA. Dies deutet darauf hin, dass nicht HR, sondern übergeordnet CHK1-vermittelte Prozesse für die Strahlenempfindlichkeit verantwortlich sind. Bestätigt wird dies durch die deutliche Strahlensensitivierung nach CHK1i, wobei die strahlenresistenteste Linie sich am stärksten sensitivieren ließ, mit VF von 3. Dies spiegelt sich auch in den Replikationsprozessen wieder, je sensitiver, desto stärker inhibiert. Momentan wird der Einfluss weiterer Inhibitoren auf die zelluläre Strahlenempfindlichkeit überprüft. Topkandidat ist RAD51i, da in einer Metabric-Analyse TNBC mit hohem CIN, also besonders aggressiven Tumoren, RAD51 und CHK1 deutlich stärker exprimiert werden als in TNBCs mit niedrigem CIN.
Schlussfolgerung: Eine veränderte Expression von HR-Proteinen und ein Stammzell-artiger Phänotyp hängen eng zusammen und determinieren gemeinsam die Therapieresistenz.

Keywords: Mammakarzinom; Homologe Rekombination (HR); DNA Reparaturweg

  • Contribution to proceedings
    DEGRO Akademie: 26. Symposium Experimentelle Strahlentherapie und Klinische Strahlenbiologie, 09.-11.02.2017, Universitätsklinikum Tübingen, Deutschland
    Abstracts DEGRO 2017. Strahlenther Onkol(2017) (Suppl) 193:S1–S194
    DOI: 10.1007/s00066-017-1137-6

Publ.-Id: 25112

Glutamine metabolism as potential target for prostate cancer radiosensitization

Tyutyunnykova, A.; Chen, O.; Richter, S.; Eisenhofer, G.; Toma, M.; Hein, L.; Novotny, V.; Zschaeck, S.; Wirth, M.; Kunz-Schughart, L.; Krause, M.; Baumann, M.; Peitzsch, C.; Dubrovska, A.

Background: A major reprogramming of cellular energy metabolism is a hallmark of tumor cells. In addition to an increased glucose uptake, highly proliferative cancer cells require additional supplies for their biosynthesis and energy production such as glutamine. Glutaminolysis also contributes to the ROS scavenging and activation of the pro-survival signaling pathways. Tumors with enhanced MYC expression, such as prostate cancer have a particularly high demand for glutamine. Herein, we investigated the role of glutamine metabolism pathways for prostate cancer radioresistance. Methods: Prostate cancer cell lines DU145, PC3, LNCaP and their radioresistant sublines (RR) were analyzed by metabolomic and gene expression profiling. The relative cell sensitivity to the inhibition of glutaminolysis was measured by analysis of viability (MTT), apoptosis and necrosis (flow cytometry and Western blotting), levels of ROS and glutathione (flow cytometry), radiosensitivity (colony formation assay, CFA), DNA repair (γH2A.X foci) and tumorigenicity in mice. Primary cell cultures from 12 tumor biopsies and matched benign tissues from prostates cancer patients were characterized by radiobiological 3D CFA and by gene expression profiling, and relative radioresistance was correlated with expression levels of the genes regulating glutaminolysis. The Cancer Genome Atlas (TCGA) datasets were analyzed for correlation of the gene expression levels and patients outcome. Results: Glutaminolysis is upregulated in RR cells, where glutamine is mostly used for production of α-ketoglutarate, which is involved in ROS scavenging and epigenetic resetting by regulation of the histone methylation, whereas α-ketoglutarate utilization for Krebs cycle is suppressed. Deprivation of glutamine or siRNA mediated inhibition of glutaminolysis leads to the induction of endoplasmic reticulum (ER) stress and inhibition of the DNA repair, clonogenicity and in vivo tumorigenicity after irradiation with a more pronounced effect for RR cells. Analysis of the TCGA datasets revealed that a high expression of the genes regulating prostate cancer glutaminolysis is significantly associated with a decrease in relapse free survival after radiotherapy. Discussion: Prostate cancer cell radioresistance is associated with alterations of glutaminolysis, whose inhibition increases the cytotoxic effects of radiation in prostate tumor cells. Expression of the proteins involved in glutaminolysis can be potentially used to predict clinical outcome after radiation therapy.

Keywords: cancer stem cells; radioresistance; glutamine metabolism; prostate cancer

  • Contribution to proceedings
    The 15th International Wolfsberg Meeting on Molecular Radiation Biology/Oncology, 17.-19.06.2017, CH-8272 Ermatingen, Switzerland

Publ.-Id: 25111

Interplay of DNA repair and stem-like phenotype determines the sensitizing effect of CHK1, RAD51 and PARP1 inhibition in TNBC

Meyer, F.; Becker, S.; Niecke, A.; Riepen, B.; Zielinski, A.; Werner, S.; Peitzsch, C.; Hein, L.; Dubrovska, A.; Wikman, H.; Windhorst, S.; Goy, Y.; Parplys, A.; Petersen, C.; Rothkamm, K.; Borgmann, K.

Breast cancer comprises a heterogeneous group of tumors of whom 20% are categorized as triple-negative (TNBC). Important biological characteristics and potential therapeutic targets of TNBC include high proliferation, a basal-like and mesenchymal phenotype and a defect in the DNA repair pathway Homologous Recombination (HR), which feeds the observed elevated chromosomal instability in these tumors. TNBCs show an enrichment of cancer stem cells and therapy resistance. This project aims to develop treatment intensification strategies based on the simultaneous exploitation of the HR-deficiency and the stem-like phenotype, using specific inhibitors for RAD51, CHK1 and PARP1 in combination with irradiation.
Expression of HR-related (RAD51, BRCA1, PTEN, CHK1, MRE11, ATR, ATM) and stem-like factors (ZEB1, E-Cadherin, ß-Catenin, ALDH1) as well as HR functionality (via RAD51 foci, MMC-sensitivity and plasmid reporter assay) were determined in the TNBC line MDA-231 WT, its two sublines preferentially metastasizing to brain (BR) or bone (SA) and in the luminal BC line MCF7. DNA replication (fiber assay) and migration assay were also tested. Radiosensitivity and the radiosensitizing effect of different inhibitors was analyzed by colony assay and correlated to the CIN in the METABRIC database.
Distinct differences in the expression of HR-related proteins were observed, with an elevated expression of CHK1, MRE11 and ATM in BR and SA relative to WT and MCF7. BR and SA showed a typical stem cell-like protein expression profile, together with a higher migration capacity, increased HR-capacity, resistance against MMC and less DNA damage. After irradiation no advantage in survival for the BR and SA cell lines was observed, suggesting that not HR, but superordinate CHK1 signaling promotes radioresistance. This was confirmed by a distinct radiosensitization after CHK1i; the most radioresistant WT cell line was most strongly sensitized, by a factor of 3. The extent of sensitization was also linked to the extent of replication inhibition. The effect of other inhibitors on radiosensitivity is currently being investigated. A second promising target is RAD51, because a METABRIC analysis (952 TNBCs) showed that in TNBC with high CIN RAD51 and CHK1 are significantly stronger expressed than in TNBC with low CIN.
In conclusion the results presented here show that DNA repair and a stem-like phenotype collude to determine resistance to tumor therapy of TNBCs with high CIN.

Keywords: Breast cancer; Homologous Recombination; DNA repair

  • Contribution to proceedings
    The 15th International Wolfsberg Meeting on Molecular Radiation Biology/Oncology, 17.-19.06.2017, Ermatingen, Switzerland
    Program 15th International Wolfsberg Meeting on Molecular Radiation Biology/Oncology

Publ.-Id: 25110

Cancer stemness: What is it and why is it important

Dubrovska, A.

no abstract available

Keywords: cancer stem cells; therapy resistance; metastasis initiating cells

Publ.-Id: 25109

Radiolabeling of nanoparticles as a versatile tool in safety research

Franke, K.; Schymura, S.; Hildebrand, H.

Identification and quantification of nanoparticulate materials in living and non-living media is mandatory for a thorough nanosafety research. However, the online and in-situ monitoring of nanoparticles in such complex natural systems as soil, natural waters, plants, sewage sludge, etc. is highly challenging, especially at environmentally relevant concentrations. Radiolabeling offers a robust method for these complex studies within a wide range concentration of nanoparticles even in the presence of background concentrations of the respective elements.

Depending on the nature of the nanoparticle and the process of interest we applied different methods for the radiolabeling of common nanoparticles, like the synthesis of the nanoparticles using radioactive starting materials, the binding of the radiotracer to the nanoparticles, the activation of the nanoparticles using proton irradiation, the recoil labeling utilizing the recoil of a nuclear reaction to implant a radiotracer into the nanoparticle, and the in-diffusion of radiotracers into the nanoparticles.

For our recent studies we produced [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 and [194Au]Pt nanoparticles (including radiolabeled commercial nanoparticle samples). Due to the choice of the used radionuclide (half-life, decay-mode) and the activity concentrations it was possible to enable different detection methods and time scales for the investigations. All these methods go along with a careful characterization of the radiolabeled nanoparticles in respect of the radiolabeling stability and nanoparticle properties.

The radiolabeled nanoparticles can easily be detected down to ng/L range and have been successfully used in investigations of the uptake of nanoparticles in plants, the distribution and mobility of nanoparticles in sewage sludge, fate of nanoparticles in wastewater treatment processes and in release studies.

Keywords: Radiolabeling; Nanoparticle

  • Lecture (Conference)
    5th-International Nuclear Chemistry Congress, 27.08.-01.09.2017, Göteborg, Schweden

Publ.-Id: 25108

Feasibility of proton pencil beam scanning treatment of free-breathing lung cancer patients

Jakobi, A.; Perrin, R.; Knopf, A.; Richter, C.

The interplay effect might degrade the dose of pencil beam scanning proton therapy to a degree that free-breathing treatment might be impossible without further motion mitigation techniques, which complicate and prolong the treatment. We assessed whether treatment of free-breathing patients without motion mitigation is feasible.
For 40 lung cancer patients, 4DCT datasets and individual breathing patterns were used to simulate 4D dynamic dose distributions of 3D treatment plans over 33 fractions delivered with an IBA universal nozzle. Evaluation was done by assessing under- and overdosage in the target structure using the parameters V90, V95, V98, D98, D2, V107 and V110. The impact of using beam-specific target volumes and the impact of changes in motion and patient anatomy in control 4DCTs were assessed.
Almost half of the patients had tumour motion amplitudes of less than 5mm. Under- and overdosage was significantly smaller for patients with tumour motion below 5mm compared to patients with larger motion (2% versus 13% average absolute reduction of V95, 2% versus 8% average increase in V107, p<0.01). Simulating a 33-fraction treatment, the dose degradation was reduced but persisted for patients with tumour motion above 5mm (average ΔV95 of <1% vs 3%, p<0.01). Beam-specific target volumes reduced the dose degradation in a fractionated treatment, but were more relevant for large motion. Repeated 4DCT revealed that changes in tumour motion during treatment might result in unexpected large dose degradations.
Tumour motion amplitude is an indicator of dose degradation caused by the interplay effect. Fractionation reduces the dose degradation allowing the unmitigated treatment of patients with small tumour motions of less than 5mm. The beam-specific target approach improves the dose coverage. The tumour motion and position needs to be assessed during treatment for all patients, to quickly react to possible changes which might require treatment adaptation.

Keywords: proton therapy; pencil beam scanning; lung cancer; interplay; motion


Publ.-Id: 25107

Time-of-Flight Telescope for ERDA at the HZDR

Julin, J.; Heller, R.

Elastic Recoil Detection Analysis (ERDA) is a near-surface heavy ion beam based elemental characterization technique, known especially for its suitability for light element analysis of thin films. The elemental composition of an unknown sample can be determined quantitatively in a single measurement, without resorting to the use of standards or information from additional measurements or models.

In the Ion Beam Center (IBC) of the Helmholtz-Zentrum Dresden-Rossendorf a Bragg Ionization Chamber (BIC) based ERDA setup has been operated successfully for many years. In the past there has also been a time-of-flight telescope installed in the same chamber. During 2017 this instrument will be upgraded with new detectors, bringing it up to date with latest experimental developments in the field.

The goal for the project is first and foremost to construct a user-friendly instrument, which can be operated reliably. Special emphasis will be put to the achievable depth resolution, without sacrificing performance in other areas. The instrument can be operated with a relatively broad energy range, with lower incident beam energy (< 10 MeV) enabling high depth resolution (2 nm) near the surface and higher energies, e.g. 20 MeV, enable excellent mass separation and better probing depth for thicker films.

In this contribution we will present the basic idea of the new setup and give some particular details on the design, expected performance and a realization time line.

  • Poster
    Workshop Ionenstrahlphysik, 13.-15.02.2017, Göttingen, Deutschland

Publ.-Id: 25106

Astrophysical S-factor of the 14N(p,γ)15O reaction at 0.4 – 1.3MeV

Wagner, L.; Akhmadaliev, S.; Anders, M.; Bemmerer, D.; Caciolli, A.; Gohl, S.; Grieger, M.; Junghans, A.; Marta, M.; Munnik, F.; Reinhardt, T. P.; Reinicke, S.; Röder, M.; Schmidt, K.; Schwengner, R.; Serfling, M.; Takács, M. P.; Szücs, T.; Vomiero, A.; Wagner, A.; Zuber, K.

The 14N(p,γ)15O reaction is the slowest reaction of the carbon-nitrogen cycle of hydrogen burning and thus determines its rate. The precise knowledge of its rate is required to correctly model hydrogen burning in asymptotic giant branch stars. In addition, it is a necessary ingredient for a possible solution of the solar abundance problem by using the solar 13N and 15O neutrino fluxes as probes of the carbon and nitrogen abundances in the solar core. After the downward revision of its cross section due to a much lower contribution by one particular transition, capture to the ground state in 15O, the evaluated total uncertainty is still 8%, in part due to an unsatisfactory knowledge of the excitation function over a wide energy range. The present work reports precise S-factor data at twelve energies between 0.357-1.292 MeV for the strongest transition, capture to the 6.79 MeV excited state in 15O, and at ten energies between 0.479-1.202 MeV for the second strongest transition, capture to the ground state in 15O. A simple R-matrix fit is performed to gauge the impact of the new data on astrophysical energies. The recently suggested slight enhancement of the ground state transition at low energy could not be confirmed. The present extrapolated zero-energy S-factors are S679(0) = 1.24±0.11 keVbarn and SGS(0) = 0.19±0.06 keVbarn.

Keywords: Nuclear Astrophysics; CNO cycle; Hydrogen burning

Publ.-Id: 25105

X-ray Structures of Succinimidyl Halobenzoates

Mamat, C.; Weiss, D.-H.; Köckerling, M.

The crystal and molecular structures of five succinimidyl halobenzoates are reported. Corresponding derivatives with the respective halo-radionuclide (18F, 76Br, 123I/124I/125I/131I) were prepared and used for the radiolabeling of biologically active (macro-)molecules (peptides, proteins, antibodies) under mild labeling conditions. All compounds crystalized from petroleum ether/ethyl acetate mixtures.

Keywords: building block; radiolabeling; [18F]SFB; SIB; SBrB

Publ.-Id: 25104

Charge Collection Efficiency in a segmented semiconductor detector interstrip region

Alarcon-Diez, V.; Vickridge, I.; Jakšić, M.; Grilj, V.; Schmidt, B.; Lange, H.

Charged particle semiconductor detectors have been used in Ion Beam Analysis (IBA) for over four decades without great changes in either design or fabrication. However one area where improvement is desirable would be to increase the detector solid angle so as to improve spectrum statistics for a given incident beam fluence. This would allow the use of very low fluences opening the way, for example, to increase the time resolution in real-time RBS or for analysis of materials that are highly sensitive to beam damage. In order to achieve this goal without incurring the costs of degraded resolution due to kinematic broadening or large detector capacitance, a single-chip segmented detector (SEGDET) was designed and built within the SPIRIT EU infrastructure project. In this work we present the Charge Collection Efficiency (CCE) in the vicinity between two adjacent segments focusing on the interstrip zone. Microbeam Ion Beam Induced Charge (IBIC) measurements with different ion masses and energies were used to perform X-Y mapping of (CCE), as a function of detector operating conditions (bias voltage changes, detector housing possibilities and guard ring configuration). We show the (CCE) in the edge region of the active area and have also mapped the charge from the interstrip region, shared between adjacent segments. The results indicate that the electrical extent of the interstrip region is very close to the physical extent of the interstrip and guard ring structure with interstrip impacts contributing very little to the complete spectrum. The interstrip contributions to the spectra that do occur, can be substantially reduced by an offline anti-coincidence criterion applied to list mode data, which should also be easy to implement directly in the data acquisition software.

Keywords: Segmented detector; IBIC; Charge Collection Efficiency; Interstrip


Publ.-Id: 25103

Effect of glutamic acid on copper sorption onto kaolinite - batch experiments and surface complexation modeling

Karimzadeh, L.; Barthen, R.; Stockmann, M.; Gruendig, M.; Franke, K.; Lippmann-Pipke, J.

High carbonate content of the European Kupferschiefer ore deposits is a challenge for acid copper leaching (pH ≤ 2). Therefore investigating the mobility behavior of Cu(II) under conditions related to an alternative, neutrophil biohydrometallurgical Cu(II) leaching approach is of interest. As glutamic acid (Glu) might be present as a component in the growth media, we studied its effects on the adsorption of Cu(II) onto kaolinite. The binary and ternary batch sorption measurements of Cu(II) and Glu onto kaolinite were performed in the presence of 10 mM NaClO4 as background electrolyte and at a pH range from 4 to 9. Sorption experiments were modeled by the charge-distribution multi-site ion complexation (CD-MUSIC) model by using single sorption site (≡SOH) and monodentate surface complexation reactions. Glu sorption on kaolinite is weak (<10%) and independent of pH. Furthermore, Glu slightly enhances the Cu(II) sorption at low pH but strongly hinders (up to 50%) the sorption at higher pH and therewith enhances copper mobility. The results of isotherms show that Cu(II)-Glu sorption onto kaolinite mimics the Freundlich model. The proposed CD-MUSIC model provides a close fit to the experimental data and predicts the sorption of Cu(II), Cu(II)-Glu and Glu onto kaolinite as well as the effect of Glu on Cu(II) mobility.

Keywords: Copper mobility; Glutamic acid; Kaolinite; Sorption; Surface complexation modeling


Publ.-Id: 25102

Provenance of uranium in a sediment core from a natural reservoir, South China: Application of Pb stable isotope analysis

Liu, J.; Luo, X.; Wang, J.; Xiao, T.; Yin, M.; Belshaw, N. S.; Lippold, H.; Kong, L.; Xiao, E.; Bao, Z.; Li, N.; Chen, Y.; Linghu, W.

As part of ongoing environmental investigations of U mining impacts, forty-two sediment samples of a nearly-half-meter-long sediment core retrieved from a natural reservoir near an active uranium (U) mining site, South China were analyzed to quantify the extent of U release and identify U release mechanism within the riverine catchment. Enrichment levels of U was dispersed not only in the surface sediments but also in deep sediments across the depth profile. Further analysis by SEM-EDS and XRD indicated that U partitioning in the depth profile was possibly controlled by complicated interplay of leaching and precipitation cycles of U-bearing minerals. Even with the relative complexity of U dispersal processes within the catchment, the Pb isotopic fingerprinting techniques allowed quantification of source inputs of the sediments by using a binary mixing model. The results revealed that along the depth profile, only 6%–50% of the sediment material is anthropogenically derived from the U ore tailing, with the other predominant proportions originated from geogenically natural weathering of granitic bedrocks. This study highlights the use of Pb isotopes as a powerful tool for quantitatively fingerprinting the sources of U dispersal in the sediment core, and natural-occurring U contamination that may become a hidden geoenvironmental health hazard in this area.

Keywords: uranium; Pb isotopes; source apportionment; binary mixing; radiogenic

Publ.-Id: 25100

Self-Organized Semiconductor Patterning by Polyatomic Broad Beam Ion Irradiation

Pilz, W.; Bischoff, L.; Böttger, R.; Laufer, P.; Tajmar, M.

Surface patterning based on self-organized nano-structures on i.e. semiconductor materials formed by heavy mono - and polyatomic ion irradiation from Liquid Metal (Alloy) Ion Sources (LMAIS) is a very promising technique. To overcome the lack of only very small treated areas by applying a Focused Ion Beam (FIB) instrument this technology was transferred into larger single-end ion beam systems like an ion implanter. Main component is an ion beam injector based on high current LMAIS, developed for space propulsion systems combined with suited ion optics allocating ion currents in the µA range in a nearly parallel beam of a few mm in diameter. The mass selection of the needed ion species can be performed either by an introduced ExB mass separator (Wien filter) and/or the existing magnet of the ion implanter itself which also can define the final ion energy up to 200 keV.
Different types of LMAIS (needle, porous emitter, capillary) are presented and characterized. The ion beam injector design is specified as well as the implementation of this module into a high current ion implanter (Danfysik Series 1090) operating at the HZDR Ion Beam Center (IBC). Finally the obtained results of large area surface modification of Ge using Bi2+ polyatomic ions from a GaBi capillary LMAIS at room temperature will be presented and discussed.

Keywords: Self-Organized Patterning; Polyatomic Ions; Broad Beam Ion Irradiation

  • Lecture (Conference)
    Nationales Treffen der deutschen Ionenstrahl-PhysikerInnen und -MaterialwissenschaftlerInnen, 12.-15.02.2017, Göttingen, Germany

Publ.-Id: 25099

Defect-induced magnetism in SiC probed by nuclear magnetic resonance

Zhang, Z. T.; Dmytriieva, D.; Molatta, S.; Wosnitza, J.; Wang, Y.; Helm, M.; Zhou, S.; Kühne, H.

We give evidence for intrinsic defect-induced bulk paramagnetism in SiC by means of 13C and 29Si nuclear magnetic resonance (NMR) spectroscopy. The temperature dependence of the internal dipole-field distribution, probed by the spin part of the NMR Knight shift and the spectral linewidth, follows the Curie law and scales very well with the macroscopic dc susceptibility. In order to quantitatively analyze the NMR spectra, a microscopic model based on dipole-dipole interactions was developed. The very good agreement between these simulations and the NMR data establishes a direct relation between the frequency distribution of the spectral intensity and the corresponding real-space volumes of nuclear spins. The presented approach by NMR can be applied to a variety of similar materials and, thus, opens a new avenue for the microscopic exploration and exploitation of diluted bulk magnetism in semiconductors.

Publ.-Id: 25098

Thallium contamination in arable soils and vegetables around a steel plant – A newly-found significant source of Tl pollution in South China

Liu, J.; Luo, X.; Wang, J.; Xiao, T.; Chen, D.; Sheng, G.; Yin, M.; Lippold, H.; Wang, C.; Chen, Y.

Thallium (Tl) is a highly toxic rare element. Severe Tl poisoning can cause neurological brain damage or even death. The present study was designed to investigate contents of Tl and other associated heavy metals in arable soils and twelve common vegetables cultivated around a steel plant in South China, a newly-found initiator of Tl pollution. Potential health risks of these metals to exposed population via consumption of vegetables were examined by calculating hazard quotients (HQ). The soils showed a significant contamination with Tl at a mean concentration of 1.34 mg/kg. The Tl levels in most vegetables (such as leaf lettuce, chard and pak choy) surpassed the maximum permissible level (0.5 mg/kg) according to the environmental quality standards for food in Germany. Vegetables like leaf lettuce, chard, pak choy, romaine lettuce and Indian beans all exhibited bioconcentration factors (BCF) and transfer factors (TF) for Tl higher than 1, indicating a hyperaccumulation of Tl in these plants. Although the elevated Tl levels in the vegetables at present will not immediately pose significant non-carcinogenic health risks to residents, it highlights the necessity of a permanent monitoring of Tl contamination in the steel-making areas.

Keywords: thallium; soil; vegetable; ecological risk; steel plant

Publ.-Id: 25097

Surface science using radioactive ions at ISOLDE: from metal surfaces to 2-dimensional materials

Potzger, K.; Molholt, T. E.; Fenta, A. S.; Pereira, L. M. C.

We review the research carried out using the apparatus for surface physics and interfaces (ASPIC), at ISOLDE, CERN. We give an overview of the research highlights since 2000, focusing on magnetic and non-magnetic metallic surfaces, and introduce the scientific program that will follow the upgrade which is currently underway, focusing on 2-dimensional materials.
ASPIC was formerly used for the growth of ultrathin metallic films and their characterization by means of perturbed angular correlation spectroscopy. Past research has mainly focused on the determination of the magnetic hyperfine field at the probe atom located on different sites at the surface such as terraces, kinks, steps as well as on the investigation of the static magnetic polarization at the interface between ferromagnetic and paramagnetic layers.
Future research on 2-dimensional materials using ASPIC is foreseen to focus on the investigation of structural and electronic properties of adatoms (adsorption sites, hybridization effects, intra-atomic charge transfer, magnetic moments, etc.). We emphasize, in this context, the exceptional capabilities of ASPIC in terms of broad applicability, high precision and low detection limits.

Keywords: Perturbed angular correlation spectroscopy; nuclear solid state physics

Publ.-Id: 25096

Backward-forward reaction asymmetry of neutron elastic scattering on deuterium

Pirovano, E.; Beyer, R.; Junghans, A. R.; Nankov, N.; Nolte, R.; Nyman, M.; Plompen, A. J. M.

A new measurement of the angular distribution of neutron elastic scattering on deuterium was carried out at the neutron time-of-flight facility nELBE. The backward-forward asymmetry of the reaction was investigated via the direct detection of neutrons scattered at the laboratory angle of 15◦ and 165◦ from a polyethylene sample enriched with deuterium. In order to extend the measurement to neutron energies below 1 MeV, 6Li glass scintillators were employed. The data were corrected for the background and the multiple scattering in the target, the events due to scattering on deuterium were separated from those due to carbon, and the ratio of the differential cross section at 15◦ and 165◦ was determined. The results, covering the energy range from 200 keV to 2 MeV, were found to be in agreement with the theoretical predictions calculated by Canton et al. [Eur. Phys. J. A 14, 225 (2002)] and by Golak et al. [Eur. Phys. J. A 50, 177 (2014)]. The comparison with the evaluated nuclear data libraries indicated CENDL-3.1, JEFF-3.2, and JENDL-4.0 as the evaluations that best describe the asymmetry of n-d scattering.
ENDF/B-VII.1 is compatible with the data for energies below 700 keV, but above the backward to forward ratio is higher than measured. ROSFOND-2010 and BROND-2.2 resulted to have little compatibility with the data.

Keywords: nELBE; neutron; time-of-flight; elastic scattering; deuterium

Publ.-Id: 25095

Guidelines to Design Electrolytes for Lithium-ion Batteries: Environmental Impact, Physicochemical and Electrochemical Properties

Flamme, B.; Rodriguez-Garcia, G.; Weil, M.; Haddad, M.; Phansavath, P.; Ratovelomanana-Vidal, V.; Chagnes, A.

Electrolytes for lithium-ion batteries (LiBs) have been put aside for too long because few new solvents have been designed to match electrolyte specifications. Conversely, more attention has been paid to synthesize new electrode materials, and more especially positive electrodes. Particularly, most of the studies dedicated to the investigation of electrolytes for LiBs have been focused on mixing different molecules. Nowadays, the development of high-voltage materials for LiBs stimulates the synthesis of new solvents and new salts more stable against oxidation. Despite the challenges, only few teams are active in this field in developing a rational approach combining physicochemistry, electrochemistry and modelling from the molecular to the macromolecular levels. After assembling a critical collection of physicochemical and electrochemical data from the literature, this paper highlights the main trends between the chemical structure of organic dipolar aprotic solvents and their physicochemical and electrochemical properties in order to provide a guide for the chemists to design new electrolytes for LiBs. This guide also includes indicators to take into account the environmental impact of solvent production by including the life cycle assessment of eight different solvents.


Publ.-Id: 25094

Elastic Moduli in Cadmium Selenide Doped with Chromium

Averkiev, N. S.; Bersuker, I. B.; Gudkov, V. V.; Zhevstovskikh, I. V.; Sarychev, M. N.; Zherlitsyn, S.; Yasin, S.; Korostelin, Y. V.

Temperature dependence of elastic moduli (C11 − C12 ) / 2 , C33 , and C44, the latter for the piezo-active and non-piezo-active versions, have been measured in the interval of 4 - 180 K at 28 - 262 MHz in a CdSe: Cr2+ crystal. Anomalies below 40 K have been found for all the moduli, except C33 . The interpretation of the results has been carried out involving the Jahn-Teller effect and relaxation between the equivalent distortions of the tetrahedral CrSe4 centers.

Publ.-Id: 25092

On the Interpretation of Principal Balances for Compositional Data Sets

Martin-Fernandez, J. A.; Pawlowsky-Glahn, V.; Egozcue, J. J.; Tolosana-Delgado, R.

To analyse compositional data (CoDa) sets it is advisable to apply the principle of working on orthonormal coordinates. Sequential Binary Partition (SBP) is a technique to construct an interpretable basis. The provided coordinates are called balances, and they are complemented with a descriptive tool, the CoDa-dendrogram. The goal of a Principal Balances method is to identify an orthonormal basis of the simplex such that the coordinates are balances approaching the properties of principal component analysis (PCA) of CoDa. PCA is one of the main tools for exploratory analysis and modelling of CoDa. However, the main shortcoming of PC's is the difficulty in interpreting the resulting coordinates because a PC is a function of all the original parts. Balances are log-contrasts resulting from a logratio of two geometric means of two groups of parts. Their interpretation is considerably simpler than the interpretation of PC's. The resulting procedures provide tools improving interpretability and intuitive dimension reduction. The algorithm to compute principal balances requires an exhaustive search along all possible sets of orthonormal balances. The consumption of computational time may be considerable for even a small number of parts. Here, to reduce this time, the sets of possible partitions for up to 15 parts is stored. For comparison, two suboptimal, but feasible, algorithms are introduced: (i) searching for balances following a constraint PC's approach; and (ii) a hierarchical cluster analysis of variables based on the Aitchison distance between parts. The properties and performance of these three algorithms are illustrated using a data set of geochemical composition of glacial sediments. Results obtained corroborate the theoretical properties of the methods: they approximate reasonably well the PC's improving the interpretability. However, the price payed is a smaller amount of variance explained by the first balances and the lack of uncorrelation between the coordinates.

  • Poster
    18th Annual Conference IAMG2017, 02.-09.09.2017, Perth, Australia

Publ.-Id: 25091

Ultrafast observation of lattice dynamics in laser-irradiated gold foils

Hartley, N. J.; Ozaki, N.; Matsuoka, T.; Albertazzi, B.; Faenov, A.; Fujimoto, Y.; Habara, H.; Harmand, M.; Inubushi, Y.; Katayama, T.; Koenig, M.; Krygier, A.; Mabey, P.; Matsumura, Y.; Matsuyama, S.; Mcbride, E. E.; Miyanishi, K.; Morard, G.; Okuchi, T.; Pikuz, T.; Sakata, O.; Sano, Y.; Sato, T.; Sekine, T.; Seto, Y.; Takahashi, K.; Tanaka, K. A.; Tange, Y.; Togashi, T.; Umeda, Y.; Vinci, T.; Yabashi, M.; Yabuuchi, T.; Yamauchi, K.; Kodama, R.

We have observed lattice expansion before the onset of compression in an optical-laser-driven target, using diffraction of femtosecond X-ray beams generated by the SACLA X-ray Free Electron Laser. The change in diffraction angle provides a direct measure of the lattice spacing, allowing the density to be calculated with a precision of +-1%. From known equation of state relations this allows estimation of the temperature responsible for the expansion as <1000 K. The subsequent ablation-driven compression was observed with a clear rise in density at later times. This demonstrates the feasibility of studying the dynamics of preheating and shock formation with unprecedented detail.

Keywords: XFEL; Diffraction; Laser-matter interaction

Publ.-Id: 25090

Energy dependence of the electron-boson coupling strength in the electron-doped cuprate superconductor Pr1.85Ce0.15CuO4−δ

Beck, M.; Klammer, M.; Rousseau, I.; Obergfell, M.; Leiderer, P.; Helm, M.; Kabanov, V. V.; Diamant, I.; Rabinowicz, A.; Dagan, Y.; Demsar, J.

The quest for a pairing boson in cuprate high-temperature superconductors is one of the outstanding Tasks of solid-state physics. Numerous time-resolved studies of pair breaking, related to pairing by time-reversal symmetry, have been performed using femtosecond optical pulses. By considering energy Relaxation pathways between charge, spin, and lattice degrees of freedom, evidence for both phonon and antiferromagnetic fluctuationmediated pairing has been obtained. Here we present a study of the superconducting-state depletion process in an electron-doped cuprate Pr1.85Ce0.15CuO4−δ , where the superconducting gap is smaller than the energy of relevant bosonic excitations. When pumping with above-gap terahertz pulses, we find that the absorbed energy density required to deplete superconductivity, Adep, matches the thermodynamic condensation energy. On the contrary, by near-infrared pumping, Adep is an order of Magnitude higher, as in the case of hole-doped, large-gap cuprates. These results imply that only a small subset of bosons, which are generated during the relaxation of optically excited carriers, contributes to pairing. This observation implies that, contrary to the common assumptions, electron-boson coupling in cuprates is strongly energy dependent.

Keywords: superconductor; terahertz; free electron laser

Publ.-Id: 25089

Field-induced gapless electron pocket in the superconducting vortex phase of YNi2B2C as probed by magnetoacoustic quantum oscillations

Nössler, J.; Seerig, R.; Yasin, S.; Uhlarz, M.; Zherlitsyn, S.; Behr, G.; Drechsler, S.-L.; Fuchs, G.; Rosner, H.; Wosnitza, J.

By use of ultrasound studies we resolved magnetoacoustic quantum oscillation deep into the mixed state of the multiband nonmagnetic superconductor YNi2B2C. Below the upper critical field, only a very weak additional damping appears that can be well explained by the field inhomogeneity caused by the flux-line lattice in the mixed state. This is clear evidence for no or a vanishingly small gap for one of the bands, namely, the spheroidal α band. This contrasts de Haas–van Alphen data obtained by use of torque magnetometry for the same sample, with a rapidly vanishing oscillation signal in the mixed state. This points to a strongly distorted flux-line lattice in the latter case that, in general, can hamper a reliable extraction of gap parameters by use of such techniques.


Publ.-Id: 25088

Interatomic coulombic decay - the mechanism for rapid deexcitation of hollow atoms

Wilhelm, R. A.; Gruber, E.; Schwestka, J.; Kozubek, R.; Madeira, T. I.; Marques, J. P.; Kobus, J.; Krasheninnikov, A. V.; Schleberger, M.; Aumayr, F.

The impact of highly charged ions onto a solid gives rise to charge exchange between the ions and target atoms, so that slow ions get neutralized in the vicinity of the surface. Using highly charged Ar and Xe ions and the surface-only material graphene as a target, we show that the neutralization and de-excitation of the ions proceeds on a sub-10 fs time scale. We further demonstrate that a multiple interatomic coulombic decay (ICD) model of highly charged ions can describe the observed ultrafast de-excitation. Other de-excitation mechanisms involving non-radiative decay and quasi- molecular orbitals formation during the impact are not important, as follows from the comparison of our experimental data with the results of first-principles calculations. Our method also enables the estimation of ICD rates directly.

Keywords: slow highly charged ion; HCI; graphene; interatomic coulombic decay; ICD

  • Open Access Logo Physical Review Letters 119(2017)10, 103401
    DOI: 10.1103/PhysRevLett.119.103401
  • Poster
    28th International Conference on Atomic Collisions in Solids - ICACS 2018, 01.-06.07.2018, Caen, Frankreich
  • Invited lecture (Conferences)
    19th International Conferences on the Physics of Highly Charged Ions - HCI 2018, 02.-07.09.2018, Lissabon, Portugal
  • Lecture (Conference)
    The International Conference on Many Particle Spectroscopy of Atoms, Molecules, Clusters and Surfaces - MPS 2018, 21.-24.08.2018, Budapest, Ungarn
  • Poster
    German Conference for Research with Synchrotron Radiation, Neutrons and Ion Beams at Large Facilities, 17.-19.09.2018, München, Deutschland


Publ.-Id: 25087

Fluor-18-markierte Substrat-basierte Radiotracer zur In-vivo-Bildgebung der Lysyloxidase

Kuchar, M.

Die Bedeutung von Lysyloxidasen im Zusammenhang mit Krebserkrankungen begründet die Notwendigkeit der nichtinvasiven bildgebenden Darstellung dieser Enzyme mittels PET.
Bisher wurde über die ln-vivo-Bildgebung von Lysyloxidasen mittels PET nicht berichtet, wodurch die in dieser Arbeit verfolgten Ansätze einen hohen Neuigkeitswert aufweisen. Allgemein haben sich in der molekularen Bildgebung Radiotracer, deren Anreicherungsmechanismen auf irreversiblen kovalenten Wechselwirkungen beruhen, als sehr erfolgreich erwiesen. Demzufolge erschien das Konzept, Bildgebungssonden auf der Basis von Substraten der Lysyloxidase zu entwickeln, die nach enzymatischem Umsatz potentiell einer kovalenten Fixierung an Matrixproteinen unterliegen können, vielversprechend. Daher wurden Peptide (Abb. 78) für die ln-vivo-Bildgebung derextrazellulären Lysyloxidase auf Grundlage des alpha1(I)-N-Telopeptids als substratbasierte Radiotracer ausgewählt und im Rahmen dieser Arbeit als Präkursaren und Referenzverbindungen synthetisiert und ausführlich charakterisiert.
Diese Markierungsmethode wurde auf weitere, für die molekulare Bildgebung potentiell interessante Peptide übertragen und evaluiert.
Um als Substrate gegenüber Lysyloxidasen zu fungieren, müssen die als Radiotracer zum Einsatz kommenden Peptide in jedem Fall einen Lysinrest aufweisen. Der für die Radiomarkierung ausgewählte Markierungsbaustein N-Succinimidyi-4-[18F]fluorbenzoat resultiert in einer 18F-Fiuorbenzoylierung von primären Aminofunktionen, wie sie am N-Terminus bzw. den Lysinseitenketten zu finden sind. Aus diesem Grund wurde eine Methode etabliert, die die 18F-Markierung selektiv an einer spezifischen Aminofunktion, die keinem enzymatischen Umsatz unterliegt, ermöglicht.
Für die Radiomarkierung wurden folgende vier Markierungsstrategien ausgewählt und hinsichtlich ihrer Selektivität beurteilt:
I. Synthese in Lösung, Steuerung der fvlarkierungsposition über den pH-Wert
II. Synthese in Lösung mit vollständigem Seitenkettenschutz
III. Synthese in Lösung mit geschütztem LOX-relevanten Lysin
IV. Synthese an der festen Phase mit variablem Seitenkettenschutz.
Durch den Einsatz der mikrowellengestützten Festphasenpeptidsynthese (SPPS) wurde die Mehrzahl der Peptide und deren Vorläufer unkompliziert hergestellt. Notwendige Modifikationen wurden in hohen Ausbeuten mittels manueller SPPS durchgeführt. Neben den Synthesen der Peptide als Präkurseren und Referenzverbindungn für die Markierungsstrategien, wurden weitere Peptidderivate für die Entwicklung von funktionellen Assays hergestellt.
Markierungsstrategie I lieferte unabhängig vom gewählten pH-Wert ein Gemisch der mono-18F-fluorbenzoylierten Regioisomere. Neben den radiomarkierten Spezies befanden sich in jeder Produktmischung zwei Zersetzungsprodukte, die während der [18F]SFB-Synthese entstanden waren. Diese Produktzusammensetzung hatte nicht nur eine aufwendige Reinigung zur Folge, sondern brachte einen großen Ausbeuteverlust mit sich.
Für Markierungsstrategie II war die Präkursorsynthese nicht praktikabel, daher wurde diese Strategie nicht weiter verfolgt.
Markierungsstrategie III führte zu geringen Ausbeuten des Rohprodukts und erforderte zusätzlich zu Strategie I einen Entschützungsschritt.
Markierungsstrategie IV erwies sich als effektivste Variante, über welche reproduzierbar die markierten Peptide mit hoher Ausbeute und radiochemischer Reinheit synthetisiert werden konnten.
Es wurde gezeigt, dass mit Markierungsstrategie IV der N-Terminus bzw. jede beliebige primäre Aminofunktion selektiv markiert werden kann. Sie ist damit eine universelle Methode, welche auf andere Peptide mit ähnlicher Fragestellung übertragen werden kann. Zur Evaluierung der Markierungsstrategie IV wurden zusätzlich drei pharmakologisch relevante Beispielpeptide (SNEW als Peptid mit für die Ligandenaffinität essentiellem N-Terminus, k7-Fragment als Peptid mit 7 Lysinresten sowie das Fragment 290-319 des Clostridium perfringens-Enterotoxins als Peptid bestehend aus 30 Aminosäuren) ausgewählt.
Die spezifische Aktivität der markierten und gereinigten Peptide lag zwischen 1-3 GBq/µmol ausgehend von ca. 3 GBq [18F]SFB mit einer spezifischen Aktivität von 20-40 GBq/µmol.
ln der Literatur sind keine Angaben zur Stärke der Telopeptid-Kollagen-lnteraktion verfügbar. Aus diesem Grund wurde die Wechselwirkung der LOX-adressierenden Peptide mit Atelokollagen mithilfe der Oberflächenplasmonresonanz-Spektroskopie quantifiziert. Bei diesen Experimenten wurden KD-Werte im oberen mikromolaren Bereich für das originale alpha1(I)-N-Telopeptid 1a ermittelt. Affinitäten in diesem Bereich legen nahe, dass nicht mit einer spezifischen Anreicherung von n.c.a.-Radiotracern auf Basis der Telopeptid-Kollagen-lnteraktion zu rechnen ist. Dieser Befund ist als günstig zu betrachten, da es Ziel war, mithilfe von 18F-markierten Telepeptidderivaten die Voraussetzung zur Bildgebung der enzymatischen Aktivität von Lysyloxidasen zu entwickeln. Eine Anreicherung der Peptide an das in Säugetieren nahezu ubiquitär vorhandene Typ I-Kollagen ist nach diesen Ergebnissen ohne enzymatische Aktivität der Lysyloxidase nicht erwünscht und es ist damit nicht zu rechnen. Die abgeleiteten Derivate des alpha1(I)-N-Telopeptids besitzen eine geringfügig höhere Affinität zum Kollagen als das authentische N-Telopeptid. Dieses Resultat ist ebenso als positiv für den Einsatz der Peptide als Radiotracer zur Visualisierung der LOX-Aktivität zu werten.
Es wurden LOX-exprimierende Tumorzelllinien ausgewählt, zum einen für die Entwicklung von Tumormodellen und zum anderen, um diese als mögliche Quellen für die Präparation des LOX-Enzyms zu nutzen. Wegen der großen Bedeutung sowohl der LOX als auch der LOXL2 im Prozess der Tumorbildung und Metastasierung wurden die Experimente auch parallel für die LOXL2 durchgeführt. Die Vorauswahl resultierte in Zelltypen aus sechs verschiedenen Tumorzelllinien (A375, FaDu, EMT-6, MDA-MB- 231 , HT-29 und MCF-7). Western-Slot-Analysen zum Nachweis der LOX in diesen Zellen ergaben für das Enzym ein charakteristisches Bandenmuster, das sich über die verschiedenen Zelllinien hinweg als konstant erwies. Die LOXL2 wurde vor allem in A375- und FaDu-Zellen als Einzelbande nachgewiesen.
Vier dieser Zelllinien wurden auf Veränderungen der Expression und Sekretion sowohl der LOX als auch der LOXL2 unter hypoxischen Kulturbedingungen untersucht (A375, EMT-6, MDA-MB-231 und MCF-7). Im Ergebnis dieser Vergleiche wurde festgestellt, dass alle getesteten Zelllinien unabhängig von den Kulturbedingungen gleichmäßig LOX exprimieren. Jedoch reichte die Expression der LOX nicht für eine Isolierung. Für die LOXL2 gelang der Nachweis einer gesteigerten Sekretion in der Zelllinie MDA-MB-231 unter hypoxischen Bedingungen.
Zusätzlich wurde die Assoziation der LOX/LOXL2 mit Proteinen der Zellmembran bzw. extrazellulären Matrix untersucht. Die Ergebnisse dieser Experimente ließen eine Assoziation der LOX mit den genannten Proteinen vermuten, während für die LOXL2 dafür keine Anhaltspunkte vorlagen. Eine Internalisierung der Tracerpeptide wurde anhand von Zellaufnahmeexperimenten ausgeschlossen.
Aus den vier Zelllinien A375, EMT-6, MDA-MB-231 und MCF-7 wurden Tumortiermodelle durch Xenotransplantation entwickelt, zwei weitere Modelle der Zelllinien FaDu und HT-29 waren im Institut verfügbar. Western-Blot-Analysen der Tumorlysate bestätigten die Untersuchungen zur LOX-Expression der kultivierten Tumorzellen in vitro. Der Nachweis der LOXL2-Expression gelang nur für A375-Tumoren mit hoher Intensität. Die LOX- und LOXL2-Expression und deren Lokalisation im A375-Tumor wurden weiterhin mittels histochemischer Untersuchungen belegt.
Die radiopharmakologische Charakterisierung der drei Tracerpeptide [18F]1c, [18F]2b und [18F]3b in gesunden männlichen Wistar-Ratten zeigte eine kurze Blutverweildauer, eine zügige renale Ausscheidung und keine Anreicherung in bestimmten Organen und Geweben. Die Untersuchungen zum Metabolisierungsverhalten der drei Tracerpeptide haben das Cyclohexapeptid [18F]3b als metabolisch inert ausgewiesen, während das N-Telopeptid [18F]1c nach 5 min zu 50% metabolisiert war. Das DPK-Peptid [18F]2b erwies sich als überraschend stabil, denn bei den ln-vivo-Studien waren nach 60 min noch über 50% intaktes Peptid nachweisbar.
Mit A375-tumortragenden NMRI-(nu/nu)-Mäusen wurden Experimente zur Aufnahme der radiomarkierten Peptide in den Tumor durchgeführt. Die Auswertung der dynamischen Kleintier-PET-Messungen und Autoradiogramme zeigten einen temporären Anstieg der Aktivität in den Tumoren, welcher sich aber deutlich von den Werten im jeweiligen Vergleichsmuskelgewebe abhob. Die höchsten SUV und ein günstiges Tumor-zu-Muskel-Verhältnis ergaben sich für DPK-Peptid [18F]2b, welches daraufhin in weiteren fünf Tumormodellen untersucht wurde; wobei analoge Ergebnisse erzielt wurden. Insgesamt wurden die größten Unterschiede des Tumor-zu-Muskel-Verhältnisses in den A375-, EMT-6- und MDA-MB-231-Tumormodellen gefunden.
Um einen Bezug der katalytischen Aktivität der LOX zur Tumoraufnahme von [18F]2b herzustellen, wurden Hemmexperimente an A375- und EMT-6-tumorentragenden Mäusen durchgeführt. Zur Hemmung der aktiven Lysyloxidase wurde den Versuchstieren vier und 24 Stunden vor Injektion von [18F]2b der Inhibitor ß-Aminopropionitril verabreicht. ln beiden Fällen wurde eine Hemmung beobachtet, wobei die Hemmung vier Stunden vor Injektion effektiver ist. Dies deutet auf einen direkten Zusammenhang zwischen Tumoraufnahme der Tracerpeptide und LOX-Aktivität hin.

  • Doctoral thesis
    TU Dresden, 2016
    Mentor: Dr. Reik Löser
    262 Seiten

Publ.-Id: 25086

Interaction of uranium (VI) with cellulose degradation products

Brinkmann, H.; Moll, H.

Cellulosic material is present in low and intermediate level wastes in considerable amounts. In the case of ground water ingressing into cementitious backfill material a hyperalkaline environment will be established. Since cellulose will be relatively fast degraded under alkaline conditions, there is a high risk that small organic, water soluble molecules will be formed. These molecules can act as complexing agents for radionuclides and thereby affecting their sorption behavior and solubility adversely. Therefore the focus of current investigations is on the interaction of uranium (VI) with Isosaccharinic acid as main degradation product as well as with acetate. The progress and results of these investigations as part of the MIND project (work package 1) will be presented.

Keywords: Cellulose; Isosaccharinic acid; Acetate; Uranium

  • Lecture (others)
    TD-315 Joint BN, GD, HT, MA Meeting 2017, 06.-07.02.2017, St. Ursanne, Schweiz

Publ.-Id: 25085

Combined fractionated external radiotherapy and internal irradiation using 90Y-labelled-Cetuximab: optimization of treatment scheduling and proof of curative potential

Dietrich, A.; Andreeff, M.; Koi, L.; Schubert, M.; Schreiner, L.; Bergmann, R.; Löck, S.; Sihver, W.; Faulhaber, D.; Pietzsch, H.-J.; Steinbach, J.; Kotzerke, J.; Baumann, M.; Krause, M.

Solid tumors can be precisely targeted with external beam radiotherapy (EBRT) but dose is limited by the surrounding tissue. The combination with radioimmunotherapy (= combination of internal and external radiotherapy - CIERT) mediates additional internal irradiation with the potential to strike also distant metastases but affecting different organs at risk. Furthermore, patient stratification is possible using corresponding PET-tracers [1].
We showed the effectiveness of CIERT using 90Y-labelled Cetuximab ([90Y]Y-Cet) and single dose EBRT in a head and neck squamous cell carcinoma xenograft model (FaDu, [2]). The presented project aimed to investigate CIERT using clinical relevant fractionated EBRT with 30 fractions (fx) over 6 weeks. However, the timing of [90Y]Y-Cet is crucial in such settings and was first optimized by modeling [90Y]Y-Cet uptake with near-infrared-labeled Cetuximab (NIR-Cet). The tracer was injected in FaDu-bearing mice at different time points during fxEBRT with differing doses. NIR-Cet uptake was longitudinally followed by in vivo optical imaging to find the optimal schedule for tumor control probability experiments to test the curative potential of CIERT.
NIR-Cet uptake was enhanced after applying low to moderate doses of fxEBRT. Thus, [90Y]Y-Cet was injected after 10 fx of EBRT in CIERT efficacy experiments. CIERT massively increased local control probability compared to EBRT alone or in combination with unlabeled Cetuximab. In the group with the lowest external dose (1 Gy/fx, total dose = 30 Gy) plus [90Y]Y-Cet all tumors were still permanently controlled (observation period = 120 d). In contrast, the total EBRT dose to cure 50% of the tumors without additional [90Y]Y-Cet injection was 63.9 Gy [58.7, 73.9].
Our results indicate a remarkably potential to improve treatment outcome if radiolabeled therapeutics are combined with fractionated external radiotherapy in a clinical relevant setting. Tumor uptake may be improved by application of some EBRT dose prior to injection. This scheduling would also enable patient stratification via a corresponding PET-tracer during ongoing therapy.

[1] A. Dietrich, L. Koi, K. Zöphel, W. Sihver, J. Kotzerke, M. Baumann, M. Krause, Br. J. Radiol. 2015, 88, 20150042
[2] L. Koi, R. Bergmann, K. Brüchner, J. Pietzsch, H.-J. Pietzsch, M. Krause, J. Steinbach, D. Zips, M. Baumann, Radiother. Oncol. 2014, 110, 362-369

  • Contribution to proceedings
    Wolfsberg Meeting 2017, 17.-19.06.2017, Ermatingen, Schweiz

Publ.-Id: 25084

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