Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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33987 Publications

Data for: An analysis for detecting potential relocation of the inventory of dry storage containers during prolonged interim storage via changes in the wall temperature fields

Wagner, M.; Reinicke, S.

Geometry files of the performed simulations (ANSYS Fluent).

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-08-06
    DOI: 10.14278/rodare.416
    License: CC-BY-4.0

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Permalink: https://www.hzdr.de/publications/Publ-31409
Publ.-Id: 31409


Strengthening of ods silver wires

Wasserbäch, W.; Skrotzki, W.; Chekhonin, P.

The present work is part of an experimental program in which the mechanical behavior and the evolution of microstructure and texture of different industrially manufactured oxide-dispersion strengthened silver alloys upon different processing steps like hot-extrusion, cold-working and further annealing have been investigated. The investigations reveal that the incoherent oxide particles strongly influence the evolution of microstructure and texture during processing and consequently the deformation behavior at room temperature. Small oxide particles cause a high strengthening of the material but only a small change of the microstructure and texture. Increasing the oxide particle size subsequently reduces the strength and changes the original microstructure and texture in a more pronounced way. The yield strength at room temperature can be explained with a linear superposition of the Orowan stress for bypassing of oxide particles by dislocations and grain boundary strengthening according to Hall-Petch. The impact of texture of the materials on the yield strength is accounted for.

Keywords: Silver; Metal matrix composites; Cold-working; Strain hardening; Texture

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  • Secondary publication expected from 09.07.2021

Permalink: https://www.hzdr.de/publications/Publ-31397
Publ.-Id: 31397


The role of contaminations in ion beam spectroscopy with freestanding 2D materials: A study on thermal treatment

Niggas, A.; Schwestka, J.; Creutzburg, S.; Gupta, T.; Eder, D.; Bayer, B. C.; Aumayr, F.; Wilhelm, R. A.

As surface-only materials, freestanding 2D materials are known to have a high level of contamination—mostly in the form of hydrocarbons, water, and residuals from production and exfoliation. For well-designed experiments, it is of particular importance to develop effective clean- ing procedures, especially since standard surface science techniques are typically not applicable. We perform ion spectroscopy with highly charged ions transmitted through freestanding atomically thin materials and present two techniques to achieve clean samples, both based on thermal treatment. Ion charge exchange and energy loss are used to analyze the degree of sample contamination. We find that even after cleaning, heavily contaminated spots remain on single layer graphene. The contamination coverage, however, clusters in strand-like structures leaving large clean areas. We present a way to discriminate clean from contaminated areas with our ion beam spectroscopy if the heterogeneity of the surface is increased sufficiently enough. We expect a similar discrimination to be necessary in most other experimental techniques.

Permalink: https://www.hzdr.de/publications/Publ-31391
Publ.-Id: 31391


PIMC data for the nonlinear electronic density response in warm-dense matter (WDM)

Dornheim, T.

This repository contains the PIMC raw data for the actual density response of the harmonically perturbed electron gas.

 

The data can be freely re-used. Please cite:

T. Dornheim, J. Vorberger, and M. Bonitz, Nonlinear Electronic Density Response in Warm Dense Matter, Phys. Rev. Lett. (in press), arXiv:2004.03229

Keywords: PIMC, density response, warm dense matter

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-08-03
    DOI: 10.14278/rodare.408
    License: CC-BY-4.0

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Permalink: https://www.hzdr.de/publications/Publ-31390
Publ.-Id: 31390


Data for: The influence of negatively charged silica nanoparticles on the surface properties of anionic surfactants: electrostatic repulsion or the effect of ionic strength?

Eftekhari, M.; Schwarzenberger, K.; Javadi, A.; Eckert, K.

The presence of negatively charged nanoparticles affects the surface activity of anionic surfactants in an aqueous phase. Recent studies suggest that electrostatic repulsive forces play an important role in increasing the surface activity of surfactants. However, the addition of nanoparticles also increases the ionic strength of the system, which has a significant impact on the surfactant's properties, e.g. its critical micelle concentration (CMC). To investigate how and to what extent electrostatic forces and ionic strength influence the behavior of ionic surfactants, the surface tension and elasticity of different solutions were measured using drop profile tensiometry as a function of the surfactant (SDBS), nanoparticle (silica) and salt (KNO3) concentration. It is observed that the surface activity of the surfactants is mainly influenced by the change in the system's ionic strength due to the presence of nanoparticles. Several characteristic parameters including the equivalent concentration of the surfactant, the CMC and the apparent partial molar area of the adsorbed surfactant are theoretically calculated and further employed to validate experimental observations. Both the nanoparticles and electrolyte decrease the CMC, while the equivalent concentration of the surfactant remains nearly constant. This paper presents a criterion to estimate the possible influence of such forces for nanoparticles of different sizes and mass fractions.

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-01-09
    DOI: 10.14278/rodare.406

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Permalink: https://www.hzdr.de/publications/Publ-31383
Publ.-Id: 31383


Practice recommendations for lung cancer radiotherapy during the COVID-19 pandemic: An ESTRO-ASTRO consensus statement

Troost, E. G. C.; Nestle, U.; Putora, P.; Bussink, J.

COVID-19 Rapid Letter

Permalink: https://www.hzdr.de/publications/Publ-31378
Publ.-Id: 31378


Benchmark hyperspectral field and laboratory data against X-ray diffraction (XRD), Portable X-ray fluorescence (pXRF) and Scanning Electron Microscopy with Mineral Liberation Analysis (SEM-MLA) data.

de La Rosa Ferna; Tolosana Delgado, R.; Gloaguen, R.

A benchmarking databank based on different spectral, multiscale, multisensor exploration technologies was created. The benchmarking is composed of 63 rock samples from drill cores from a polymetallic (Cu-Zn-Pb) massive sulphide deposit in the Iberian Pyrite Belt. The samples had been analyzed by portable XRF, point hyperspectral spectrometer, portable FTIR, VNIR-SWIR imaging hyperspectral sensor and a LWIR imaging thermal hyperspectral sensor.

The mineralogical information from the boreholes will be complemented with mineral chemistry extracted from the spectral features of the alteration minerals that display chemical variations. The chemical variations in minerals generate shifts on the position of the metal-OH vibrational absorptions. This systematic variation can be recorded using the SWIR wavelength region of hyperspectral data. The shifts sometimes occur systematically with respect to ore deposits and hence mineral chemical information extracted from hyperspectral surveys can be used for mineral exploration. The mineral chemistry of the samples will be validated using scanning electron microscopy data integrated with the mineral liberation analysis (SEM-MLA).

In order to apply this type of research techniques aiming at a 3D model of the alteration areas of the entire deposit based on the hyperspectral data, it is essential to have the availability of drill cores along the whole extension of the mineral deposit. Consequently, the research was focused in a study area in the Southern Spain, the Elvira deposit of the MATSA–VALORIZA mining company, where 7 km of drill core were scanned with the hyperspectral sensors.

New exploration technologies (NEXT) is a project that has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement nº 776804.

Keywords: Benchmarking; Hyperspectral; Drill core scanner; pFTIR; PXRF; VNIR - SWIR - LWIR

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-07-02
    DOI: 10.14278/rodare.392

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Permalink: https://www.hzdr.de/publications/Publ-31373
Publ.-Id: 31373


Brain geometry matters in Alzheimer disease progression: a simulation study

Hoore, M.; Kelling, J.; Sayadmanesh, M.; Mitra, T.; Schips, M.; Meyer-Hermann, M.

The Amyloid cascade hypothesis (ACH) for Alzheimer's disease (AD) is modeled over the whole brain tissue with a set of partial differential equations. Our results show that the amyloid plaque formation is critically dependent on the secretion rate of amyloid β(Aβ), which is proportional to the product of neural density and neural activity. Neural atrophy is similarly related to the secretion rate of Aβ. Due to a heterogeneous distribution of neural density and brain activity throughout the brain, amyloid plaque formation and neural death occurs heterogeneously in the brain. The geometry of the brain and microglia migration in the parenchyma bring more complexity into the system and result in a diverse amyloidosis and dementia pattern of different brain regions. Although the pattern of amyloidosis in the brain cortex from in-silico results is similar to experimental autopsy findings, they mismatch at the central regions of the brain, suggesting that ACH is not able to explain the whole course of AD without considering other factors, such as tau-protein aggregation or neuroinflammation.

Keywords: Neurdegenerative disease; Alzheimer's disease; Amyloid cascade hypothesis; mult-phase model

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Permalink: https://www.hzdr.de/publications/Publ-31371
Publ.-Id: 31371


Yu-Shiba-Rusinov bands in ferromagnetic superconducting diamond

Zhang, G.; Samuely, T.; Iwahara, N.; Kačmarčík, J.; Wang, C.; May, P. W.; Jochum, J. K.; Onufriienko, O.; Szabó, P.; Zhou, S.; Samuely, P.; Moshchalkov, V. V.; Chibotaru, L. F.; Rubahn, H.-G.

The combination of different exotic properties in materials paves the way for the emergence of their new potential applications. An example is the recently found coexistence of the mutually antagonistic ferromagnetism and superconductivity in hydrogenated boron-doped diamond, which promises to be an attractive system with which to explore unconventional physics. Here, we show the emergence of Yu-Shiba-Rusinov (YSR) bands with a spatial extent of tens of nanometers in ferromagnetic superconducting diamond using scanning tunneling spectroscopy. We demonstrate theoretically how a two-dimensional (2D) spin lattice at the surface of a three-dimensional (3D) superconductor gives rise to the YSR bands and how their density-of-states profile correlates with the spin lattice structure. The established strategy to realize new forms of the coexistence of ferromagnetism and superconductivity opens a way to engineer the unusual electronic states and also to design better-performing superconducting devices.

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-05-25
    DOI: 10.14278/rodare.341
    License: CC-BY-4.0

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Permalink: https://www.hzdr.de/publications/Publ-31369
Publ.-Id: 31369


Tailoring Magnetic Features in Zigzag-Edged Nanographenes by Controlled Diels–Alder Reactions

Ajayakumar, M.; Fu, Y.; Liu, F.; Komber, H.; Tkachova, V.; Xu, C.; Zhou, S.; Popov, A.; Liu, J.; Feng, X.

Nanographenes (NGs) with tunable electronic and magnetic properties have attracted enormous attention in the realm of carbon-based nanoelectronics. In particular, NGs with biradical character at the ground state are promising building units for molecular spintronics. However, most of the biradicaloids are susceptible to oxidation under ambient conditions and photolytic degradation, which hamper their further applications. Herein, we demonstrated the feasibility of tuning the magnetic properties of zigzag-edged NGs in order to enhance their stability via the controlled Diels–Alder reactions of peri-tetracene (4-PA). The unstable 4-PA (y0=0.72; half-life, t1/2=3 h) was transformed into the unprecedented benzo-peri-tetracenes (BPTs) by a one-side Diels–Alder reaction, which featured a biradical character at the ground state (y0=0.60) and exhibited remarkable stability under ambient conditions for several months. In addition, the fully zigzag-edged circumanthracenes (CAs) were achieved by two-fold or stepwise Diels–Alder reactions of 4-PA, in which the magnetic properties could be controlled by employing the corresponding dienophiles. Our work reported herein opens avenues for the synthesis of novel zigzag-edged NGs with tailor-made magnetic properties.

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-05-25
    DOI: 10.14278/rodare.343
    License: CC-BY-4.0

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Permalink: https://www.hzdr.de/publications/Publ-31366
Publ.-Id: 31366


Magnetocaloric effect in GdNi2 for cryogenic gas liquefaction studied in magnetic fields up to 50 T

Taskaev, S.; Khovaylo, V.; Skokov, K.; Liu, W.; Bykov, E.; Ulyanov, M.; Bataev, D.; Basharova, A.; Kononova, M.; Plakhotskiy, D.; Bogush, M.; Gottschall, T.; Gutfleisch, O.

Natural gases have played a significant role in different sectors of the global economy. Recent analyses have shown that the world’s gas consumption doubled over the last three decades; further growth of the gas consumption is predicted, rising to be 23%–28% of the total primary energy demand by 2030. Therefore, liquefaction of natural gases rapidly gains global importance. In this context, magnetic refrigeration emerges as a modern energy-saving technique, which is an alternative to the traditional gas-compression refrigeration. This paper is devoted to the study of the magnetocaloric effect in magnetic fields up to 10 T on a representative of the Laves phase alloys, GdNi2, which is considered as a perspective material for liquefaction of natural gases. For a magnetic field change of 10 T, the magnetic entropy change ΔSm≈−17 J/kg K and the adiabatic temperature change ΔTad ≈ 6.8 K was attained around Curie temperature TC = 70 K. The maximal value of the adiabatic temperature change measured directly in pulsed magnetic fields up to 50 T is ΔTad ≈ 15 K.

Permalink: https://www.hzdr.de/publications/Publ-31361
Publ.-Id: 31361


Effect of uniaxial stress on the electronic band structure of NbP

Schindler, C.; Noky, J.; Schmidt, M.; Felser, C.; Wosnitza, J.; Gooth, J.

The Weyl semimetal NbP exhibits a very small Fermi surface consisting of two electron and two hole pockets, whose fourfold degeneracy in k space is tied to the rotational symmetry of the underlying tetragonal crystal lattice. By applying uniaxial stress, the crystal symmetry can be reduced, which successively leads to a degeneracy lifting of the Fermi-surface pockets. This is reflected by a splitting of the Shubnikov–de Haas frequencies when the magnetic field is aligned along the c axis of the tetragonal lattice. In this study, we present the measurement of Shubnikov–de Haas oscillations of single-crystalline NbP samples under uniaxial tension, combined with state-of-the-art calculations of the electronic band structure. Our results show qualitative agreement between calculated and experimentally determined Shubnikov–de Haas frequencies, demonstrating the robustness of the band-structure calculations upon introducing strain. Furthermore, we predict a significant shift of the Weyl points with increasing uniaxial tension, allowing for an effective tuning to the Fermi level at only 0.8% of strain along the a axis.

Permalink: https://www.hzdr.de/publications/Publ-31360
Publ.-Id: 31360


Vacancy-solute clustering in Fe-Cr alloys after neutron irradiation

Konstantinovic, M. J.; Ulbricht, A.; Brodziansky, T.; Castin, N.; Malerba, L.

Origin-files, data for figure 3 and figure 4 of publication in J. Nucl. Mater.

Keywords: Neutron irradiation, FeCr alloys and steels

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-07-21
    DOI: 10.14278/rodare.400
    License: CC-BY-4.0

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Permalink: https://www.hzdr.de/publications/Publ-31356
Publ.-Id: 31356


CFD Modeling and Experimental Validation of Top-Submerged-Lance Gas Injection in Liquid Metal

Reuter, M. A.; Akashi, M.; Kriebitzsch, S.; Meyer, B.; Obiso, D.; Eckert, S.; Richter, A.

In the present work, the dynamics of a downward gas injection into a liquid metal bath is studied using a numerical modeling approach, and validated with experimental data. As in a top-submerged-lance (TSL) smelter, gas is injected through the lance into the melt. By this means, the properties of the liquid are closer to the actual industrial process than the typically used water/glycerol–air/helium systems. The experimental activity was carried out in a quasi-2D vessel (144 x 144 x 12 mm3) filled with GaInSn, a metal alloy with eutectic at room temperature. Ar was used as the inert gas. The structure and behavior of the gas phase were visualized and quantitatively analyzed by X-ray radiography and high-speed imaging. Computational Fluid Dynamics (CFD) was applied to simulate the multiphase flow in the vessel and the Volume Of Fluid (VOF) model chosen to track the interface using a geometric reconstruction of the interface. Three different vertical lance positions were investigated, applying a gas flow rate of Qgas = 6850 cm³/min: The CFD model is able to predict the bubble detachment frequency, the average void fraction distributions, and the bubble size and hydrodynamic behavior, demonstrating its applicability to simulate such complex multiphase systems. The use of numerical models also provides a deep insight into fluid dynamics to study particular phenomena such as bubble break-up and free surface oscillations.

Keywords: top-submerged-lance (TSL),; X-ray,; Computational Fluid Dynamics (CFD),; Volume Of Fluid (VOF),

Permalink: https://www.hzdr.de/publications/Publ-31353
Publ.-Id: 31353


Adenosine/A2B Receptor Signaling Ameliorates the Effects of Aging and Counteracts Obesity

Gnad, T.; Navarro, G.; Lahesmaa, M.; Reverte-Salisa, L.; Copperi, F.; Cordomi, A.; Naumann, J.; Hochh€Auser, A.; Haufs-Brusberg, S.; Wenzel, D.; Suhr, F.; Zenius Jespersen, N.; Scheele, C.; Tsvilovskyy, V.; Brinkmann, C.; Rittweger, J.; Dani, C.; Kranz, M.; Deuther-Conrad, W.; Eltzschig, H. K.; Niemi, T.; Taittonen, M.; Brust, P.; Nuutila, P.; Pardo, L.; Fleischmann, B. K.; Bleuher, M.; Franco, R.; Bloch, W.; Virtanen, K. A.; Pfeifer, A.

The combination of aging populations with the obesity pandemic results in an alarming rise in non-communicable diseases. Here, we show that the enigmatic adenosine A2B receptor (A2B) is abundantly expressed in skeletal muscle (SKM) as well as brown adipose tissue (BAT) and might be targeted to counteract age-related muscle atrophy (sarcopenia) as well as obesity. Mice with SKM-specific deletion of A2B exhibited sarcopenia, diminished muscle strength, and reduced energy expenditure (EE), whereas pharmacological A2B activation counteracted these processes. Adipose tissue-specific ablation of A2B exacerbated age-related processes and reduced BAT EE, whereas A2B stimulation ameliorated obesity. In humans, A2B expression correlated with EE in SKM, BAT activity, and abundance of thermogenic adipocytes in white fat. Moreover, A2B agonist treatment increased EE from human adipocytes, myocytes, and muscle explants. Mechanistically, A2B forms heterodimers required for adenosine signaling. Overall, adenosine/A2B signaling links muscle and BAT and has both anti-aging and anti–obesity potential.

Permalink: https://www.hzdr.de/publications/Publ-31349
Publ.-Id: 31349


Numerical study of the appearance of short-circuits in liquid metal batteries

Benard, S.

The report gives an overview on small-scale interface instabilities in liquid metal batteries.

  • Other
    École normale supérieure Paris-Saclay, 2020

Permalink: https://www.hzdr.de/publications/Publ-31347
Publ.-Id: 31347


Magnetoelectric coupling in a frustrated spinel studied using high-field scanning probe microscopy

Rossi, L.; Brüning, D.; Ueda, H.; Scurschii, I.; Lorenz, T.; Bryant, B.

Below its Neél temperature, the frustrated magnet CdCr2O4 exhibits an antiferromagnetic spin-spiral ground state. Such states can give rise to a sizable magnetoelectric coupling. In this report, we measure the electric polarization induced in single-crystalline CdCr2O4 by large applied magnetic field. Because the detection of a macroscopic polarization is hindered by the structural domains in the tetragonal spin-spiral phase, we have pioneered an alternative method of measuring polarization induced by high magnetic fields, using electrostatic force microscopy. This method enables us to measure polarization from nanoscale areas of the sample surface, as well as imaging how charge inhomogeneities change with magnetic field.

Permalink: https://www.hzdr.de/publications/Publ-31346
Publ.-Id: 31346


Vacancy-solute clustering in Fe-Cr alloys after neutron irradiation

Konstantinovic, M. J.; Ulbricht, A.; Brodziansky, T.; Castina, N.; Malerba, L.

Vacancy-solute clustering in neutron irradiated Fe-Cr alloys with various concentrations of Cr and minor solutes (Ni, Si and P) were studied by using
coincidence Doppler broadening spectroscopy and small angle neutron scattering techniques. The results from both experiments, supported by an object kinetic Monte Carlo model, show in a very consistent way the existence and formation of vacancy-CrNiSiP clusters that play detrimental role in irradiation hardening. Similar solute cluster number density of about 30 to 50 x10^16cm-3 and an average diameter of about 1 nm were estimated for all alloys containing minor solutes, irrespectively of the chromium content. In Fe9Cr ferritic and Fe9Cr ferritic/martensitic alloys, with significantly reduced concentration of minor solute elements, the main defects are vacancy clusters, with an average cluster size size of about 10 and 2 vacancies, respectively. Large concentration of alpha'-precipitates was observed in Fe14Cr(NiSiP). However, both vacancy clusters and alpha'-precipitates provide significantly less impact to hardening in comparison to vacancy-CrNiSiP clusters. The fact that vacancy clustering in Fe9Cr ferritic alloy resembles that of pure iron suggests that Cr solutes may play lesser role in irradiation hardening of ferritic alloys and steels than previously believed.

Keywords: Neutron irradiation; FeCr alloys; Steels

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  • Secondary publication expected from 24.07.2021

Permalink: https://www.hzdr.de/publications/Publ-31344
Publ.-Id: 31344


Band Bending and Valence Band Quantization at Line Defects in MoS2

Murray, C.; van Efferen, C.; Jolie, W.; Fischer, J. A.; Hall, J.; Rosch, A.; Krasheninnikov, A.; Komsa, H.-P.; Michely, T.

The variation of the electronic structure normal to 1D defects in quasi-freestanding MoS2, grown by molecular beam epitaxy, is investigated through high resolution scanning tunneling spectroscopy at 5K. Strong upward bending of valence and conduction bands toward the line defects is found for the 4|4E mirror twin boundary and island edges but not for the 4|4P mirror twin boundary. Quantized energy levels in the valence band are observed wherever upward band bending takes place. Focusing on the common 4|4E mirror twin boundary, density functional theory calculations give an estimate of its charging, which agrees well with electrostatic modeling. We show that the line charge can also be assessed from the filling of the boundary-localized electronic band, whereby we provide a measurement of the theoretically predicted quantized polarization charge at MoS2 mirror twin boundaries. These calculations elucidate the origin of band bending and charging at these 1D defects in MoS2. The 4|4E mirror twin boundary not only impairs charge transport of electrons and holes due to band bending, but holes are additionally subject to a potential barrier, which is inferred from the independence of the quantized energy landscape on either side of the boundary.

Keywords: 2D materials; Line defects; first-principles calculations

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  • Secondary publication expected from 30.06.2021

Permalink: https://www.hzdr.de/publications/Publ-31342
Publ.-Id: 31342


Strain robust spin gapless semiconductors/half-metals in transition metal embedded MoSe2 monolayer

Yang, Q.; Kou, L.; Hu, X.; Wang, Y.; Lu, C.; Krasheninnikov, A.; Sun, L.

The realization of spin gapless semiconductor (SGS) and half-metal (HM) behavior in two-dimensional (2D) transition metal (TM) dichalcogenides is highly desirable for their applications in spintronic devices. Here, using density functional theory calculations, we demonstrate that Fe, Co, Ni substitutional impurities can not only induce magnetism in MoSe2 monolayer, but also convert the semiconducting MoSe2 to SGS/HM system. We also study the effects of mechanical strain on the electronic and magnetic properties of the doped monolayer. We show that for all TM impurities we considered, the system exhibits the robust SGS/HM behavior regardless of biaxial strain values. Moreover, it is found that the magnetic properties of TM–MoSe2 can effectively be tuned under biaxial strain by controlling the spin polarization of the 3d orbitals of Fe, Co, Ni atoms. Our findings offer a new route to designing the SGS/HM properties and modulating magnetic characteristics of the TM–MoSe2 system and may also facilitate the implementation of SGS/HM behavior and realization of spintronic devices based on other 2D materials.

Keywords: 2D materials, first-principles simulations, magnetism

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  • Secondary publication expected from 17.06.2021

Permalink: https://www.hzdr.de/publications/Publ-31341
Publ.-Id: 31341


Reversible crystalline-to-amorphous phase transformation in monolayer MoS under grazing ion irradiation

Valerius, P.; Kretschmer, S.; V. Senkovskiy, B.; Wu, S.; Hall, J.; Herman, A.; Ehlen, N.; Ghorbani Asl, M.; Grüneis, A.; Krasheninnikov, A.; Michely, T.

By combining scanning tunneling microscopy, low-energy electron diffraction, photoluminescence and Raman spectroscopy experiments with molecular dynamics simulations, a comprehensive picture of the structural and electronic response of a monolayer of MoS2 to 500 eV Xe+ irradiation is obtained. The MoS2 layer is epitaxially grown on graphene/Ir(1 1 1) and analyzed before and after irradiation in situ under ultra-high vacuum conditions. Through optimized irradiation conditions using low-energy ions with grazing trajectories, amorphization of the monolayer is induced already at low ion fluences of 1.5 × 1014 ions cm−2 and without inducing damage underneath the MoS2 layer. The crystalline-to-amorphous transformation is accompanied by changes in the electronic properties from semiconductor-to-metal and an extinction of photoluminescence. Upon thermal annealing, the re-crystallization occurs with restoration of the semiconducting properties, but residual defects prevent the recovery of photoluminescence.

Keywords: 2D materilas, irradiation, defects, atomistic simulations

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  • Secondary publication expected from 06.01.2021

Permalink: https://www.hzdr.de/publications/Publ-31340
Publ.-Id: 31340


Increasing the Diversity and Understanding of Semiconductor Nanoplatelets by Colloidal Atomic Layer Deposition

Reichhelm, A.; Hübner, R.; Damm, C.; Nielsch, K.; Eychmüller, A.

Nanoplatelets (NPLs) are a remarkable class of quantum confined materials with size-dependent optical properties, which are determined by the defined thickness of the crystalline platelets. To increase the variety of species, the colloidal atomic layer deposition method is used for the preparation of increasingly thicker CdSe NPLs. By growing further crystalline layers onto the surfaces of 4 and 5 monolayers (MLs) thick NPLs, species from 6 to 13 MLs are achieved. While increasing the thickness, the heavy-hole absorption peak shifts from 513 to 652 nm, leading to a variety of NPLs for applications and further investigations. The thickness and number of MLs of the platelet species are determined by high-resolution transmission electron microscopy (HRTEM) measurements, allowing the interpretation of several contradictions present in the NPL literature. In recent years, different assumptions are published, leading to a lack of clarity in the fundamentals of this field. Regarding the ongoing scientific interest in NPLs, there is a certain need for clarification, which is provided in this study.

Keywords: CdSe; colloidal atomic layer deposition; nanoplatelets

Permalink: https://www.hzdr.de/publications/Publ-31339
Publ.-Id: 31339


Unraveling Structure and Device Operation of Organic Permeable Base Transistors

Darbandy, G.; Dollinger, F.; Formánek, P.; Hübner, R.; Resch, S.; Roemer, C.; Fischer, A.; Leo, K.; Kloes, A.; Kleemann, H.

Organic permeable base transistors (OPBTs) are of great interest for flexible electronic circuits, as they offer very large on-current density and a record-high transition frequency. They rely on a vertical device architecture with current transport through native pinholes in a central base electrode. This study investigates the impact of pinhole density and pinhole diameter on the DC device performance in OPBTs based on experimental data and TCAD simulation results. A pinhole density of NPin = 54 μm−2 and pinhole diameters around LPin = 15 nm are found in the devices. Simulations show that a variation of pinhole diameter and density around these numbers has only a minor impact on the DC device characteristics. A variation of the pinhole diameter and density by up to 100% lead to a deviation of less than 4% in threshold voltage, on/off current ratio, and sub-threshold slope. Hence, the fabrication of OPBTs with reliable device characteristics is possible regardless of statistical deviations in thin film formation.

Keywords: organic permeable base transistors; organic electronics; technology computer-aided design simulation

Permalink: https://www.hzdr.de/publications/Publ-31338
Publ.-Id: 31338


Direct and Reversible Electron Transfer Between Eu²⁺ and Sm³⁺

Joos, J. J.; van der Heggen, D.; Amidani, L.; Smet, P. F.; Seijo, L.; Barandiarán, Z.

Electron transfer between two different lanthanide dopants is a frequent phenomenon. In some notable cases, the transfer can be reversible, allowing for energy storage and release. Although the mechanism of this process has not been proven theoretically, it is generally hypothesized and accepted that the electrons are conveyed by the conduction band of the host. We show here that the well-known reversible electron phototransfer from Eu2+ to Sm3+ in CaF2 is direct, from metal-to-metal. Furthermore, we substantiate that the backtransfer can be induced in the visible, suggesting the CaF2:Eu,Sm material can be used in dosimetry. These conclusions are drawn using many-electron multiconfigurational theory to calculate dopant-to-host and dopant-to-dopant electron transfer energies, while high-resolution X-ray spectroscopy with visible-light excitation evidences the reversible valence changes. These new insights into redox processes in luminescent materials are expected to guide the development of new functional materials such as storage or persistent phosphors.

Permalink: https://www.hzdr.de/publications/Publ-31337
Publ.-Id: 31337


Data set on DBTTs from SPT and CVN

Altstadt, E.; Bergner, F.; Houska, M.

The data set is related to a manuscript entitled "Use of the small punch test for the estimation of ductile-to-brittle transition temperature shift of irradiated steels". Contents raw data of small punch tests, evaluation data of small punch tests and Charpy impact tests, correlation and regression analysis.

Keywords: small punch test; Charpy impact test; ductile-to-brittle-transition temperature; reactor pressure vessel steel; neutron irradiation

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-07-16
    DOI: 10.14278/rodare.396

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Permalink: https://www.hzdr.de/publications/Publ-31334
Publ.-Id: 31334


DGN-Handlungsempfehlung (S1-Leitlinie): PSMA-Liganden-PET/CT in der Diagnostik des Prostatakarzinoms

Afshar-Oromieh, A.; Eiber, M.; Fendler, W.; Schmidt, M.; Rahbar, K.; Ahmadzadehfar, H.; Umutlu, L.; Hadaschik, B.; Hakenberg, O. W.; Formara, P.; Kurth, J.; Neels, O.; Wester, H. J.; Schwaiger, M.; Kopka, K.; Haberkorn, U.; Hermann, K.; Krause, B. J.

Das Ziel der vorliegenden Leitlinie ist es, den Arzt bei der Indikationsstellung, der standardisierten Durchführung, der Interpretation und der Dokumentation der Befunde einer Positronen-Emissions-Tomographie/Computertomographie (PET/CT) mit PSMA-Liganden bei Patienten mit Prostatakarzinom zu unterstützen. Es werden Empfehlungen zu Patientenselektion, Bilderfassung, Interpretation und Befundung ausgesprochen sowie Limitationen der PSMA-Liganden-PET/CT präsentiert. Die Leitlinie basiert auf einer Zusammenführung wissenschaftlicher Veröffentlichungen, Empfehlungen der Autoren und evidenzbasierter Daten.

  • Open Access Logo PSMA-Liganden-PET/CT in der Diagnostik des Prostatakarzinoms 10(2019) 031-055

Permalink: https://www.hzdr.de/publications/Publ-31331
Publ.-Id: 31331


Nature of Magnetic Excitations in the High-Field Phase of α-RuCl3

Ponomaryov, O.; Zviagina, L.; Wosnitza, J.; Lampen-Kelley, P.; Benerjee, A.; Yan, J.-Q.; Bridges, C. A.; Mandrus, D. G.; Nagler, S. E.; Zvyagin, S.

We present comprehensive electron spin resonance (ESR) studies of in-plane oriented single crystals of α-RuCl3, a quasi-two-dimensional material with honeycomb structure, focusing on its high-field spin dynamics. The measurements were performed in magnetic fields up to 16 T, applied along the [110] and [100] directions. Several ESR modes were detected. Combining our findings with recent inelastic neutronand Raman-scattering data, we identified most of the observed excitations. Most importantly, we show that the low-temperature ESR response beyond the boundary of the magnetically ordered region is dominated by single- and two-particle processes with magnons as elementary excitations. The peculiarities of the excitation spectrum in the vicinity of the critical field are discussed.

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Permalink: https://www.hzdr.de/publications/Publ-31328
Publ.-Id: 31328


Earthquake-induced deformation structures in glacial sediments—evidence on fault reactivation and instability at the Vaalajärvi fault in northern Fennoscandia

Ojala, A. E. K.; Mattila, J.; Middleton, M.; Ruskeeniemi, T.; Palmu, J.-P.; Nordbäck, N.; Kirsch, M.; Lorenz, S.; Zimmermann, R.; Andreani, L.; Jackisch, R.; Unger, G.; Gloaguen, R.; Sutinen, R.

Late and postglacial reverse faults and seismically-induced landslides are characteristic features of deglaciated terrain in the northern Fennoscandia. The main focus of this study was to investigate the rupturing history of the reverse Vaalajärvi fault complex in Sodankylä, Finland, based on remote sensing, on-site geophysics and sedimentology in excavations trenched across the faulted terrain. In addition to the previously known NNW–SSE-trending Vaalajärvi segment, we discovered six new SW–NE-trending fault segments that probably belong to the same Vaalajärvi ‘postglacial’ fault complex. Our analysis indicate that the Vaalajärvi fault segment was triggered by stress change caused by ruptures on the surrounding SW–NE-trending reverse faults. In total, at least two to three slip events have taken place in different segments of the Vaalajärvi complex since the Early Weichselian with the most recent event(s) being postglacial in timing. By using the scaling laws of fault surface rupture length and offset and under different scenarios of which segments or systems ruptured in a single or separate event, we estimate that the Vaalajärvi complex potentially hosted an earthquake that ranged between Mw ≈ 6.7–7.0. This magnitude is comparable to the landslide-inferred magnitudes in the Vaalajärvi area.

Keywords: Postglacial fault; Paleoseismology; Moment magnitude; LiDAR; Vaalajärvi; Finland

Permalink: https://www.hzdr.de/publications/Publ-31327
Publ.-Id: 31327


Halogen Bonded Assemblies of Arylene-imides and -diimides: Insight from Electronic, Structural and Computational studies

Mandal, K.; Bansal, D.; Kumar, Y.; Khan, R.; Shukla, J.; Mukhopadhyay, P.

Halogen bonding interactions in electron deficient π-scaffolds has largely been underexplored. Herein, we have studied the halogen bonding properties of arylene-imide/-diimide-based electron deficient scaffolds. We probed the influence of: scaffold size, e.g. from small phthalimide (PTMI), moderately-sized pyromelliticdiimide (PMDI) or naphthalenediimides (NDIs) to large perylenediimide (PDI); axial-group modifications; varied number of halogens, etc. on the halogen bonding and its self-assembly in a set of nine molecules. The structural modification leads to tunable optical as well as redox property. Gratifyingly, we realized single crystals of all the nine systems, which revealed Br∙∙∙O, Br∙∙∙Br or Br∙∙∙π halogen bonding interactions, with few systems capable of forming all the three-types. These interactions lead to halogen bonded rings (up to 12-membered), which propagate to form stacked 1D-, 2D- or corrugated sheets. We also identified few outliers, e.g. molecule which prefer C-H∙∙∙O hydrogen bonding over halogen bonding; or a non-centrosymmetric organization over the centrosymmetric ones. Computational studies based on Atoms in Molecules (AIM) and Natural Bond Orbital (NBO) analysis provided
further insight into the halogen bonding interactions. This study can lead to a predictive design tool-box to further explore related systems on surfaces reinforced by these weak directional forces.

Permalink: https://www.hzdr.de/publications/Publ-31326
Publ.-Id: 31326


Benchmarking of Computational Fluid Dynamics Codes for Reactor Vessel Design

Krause, M.; Smith, B.; Höhne, T.; In, W. K.

Computational Fluid Dynamics (CFD) codes have reached a level of maturity, at least for single-phase applications, to be utilized in the design process of Nuclear Power Plant (NPP) components, such that advanced NPPs over the past years have increasingly utilized CFD codes in their design. A recently completed Cooperative Research Project (CRP) addressed the application of CFD codes to the process of optimizing the design of components in Pressurized Water-cooled Reactors (PWRs). Following several initiatives within the IAEA where CFD codes have been applied to situations of interest in nuclear reactor technology, this CRP aimed to contribute to a consistent application of CFD codes by establishing a common platform to assess their capabilities and level of qualification.

Eleven participant organizations from nine Member States performed simulations against four “CFD-grade” experiments performed to investigate key phenomena for CFD simulations. Two are based on test data from the ROCOM (ROssendorf COolant Mixing) facility at HZDR in Germany, and another two are based on rod-bundle experiments in the OFEL (Omni Flow Experimental Loop) facility at KAERI in Korea.

This paper outlines the objectives of the CRP, provides a description of the test facilities and experiments, and discusses selected results obtained for the four above benchmark exercises.

Keywords: Computational Fluid Dynamics; Reactor Design; CFD benchmark

  • Other report
    Wien: IAEA, 2020
    63 Seiten

Permalink: https://www.hzdr.de/publications/Publ-31324
Publ.-Id: 31324


Protecting-Group-Directed Diastereo- and Enantioselective Approach to Substituted Chiral Tetrahydropyrroloquinolines.

Chaudhari, T.; Mallampudi, N.; Bansal, D.; Mohapatra, D.; Tandon, V.

A novel synthetic method for chiral tricyclic tetrahydropyrroloquinolines following a protecting‐group‐directed domino reaction consisting of Michael addition and Mannich cyclization under mild reaction conditions was developed.

Permalink: https://www.hzdr.de/publications/Publ-31323
Publ.-Id: 31323


Multi Geometry Critical Heat Flux Observation facility (MORENA): Investigation of Critical Heat Flux (CHF) at 3 K and 5 K subcooled flow boiling - Infrared thermography (IR) data set

Geißler, T.; Franz, R.; Hampel, U.

Experiments have been conducted to investigate the boiling heat transfer and local development of Critical Heat Flux (CHF) at subcooled flow boiling in a heated vertical tube. This data set contains the raw and processed Infrared thermography (IR) data along with measured operational data of the experimental facility for 3 K and 5 K subcooled flow boiling.

Keywords: Critical Heat Flux (CHF); Subcooled flow boiling; Infrared thermography

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-07-14
    DOI: 10.14278/rodare.394

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Permalink: https://www.hzdr.de/publications/Publ-31320
Publ.-Id: 31320


Superconductivity with broken time-reversal symmetry inside a superconducting s-wave state

Grinenko, V.; Sarkar, R.; Kihou, K.; Lee, C. H.; Morozov, I.; Aswartham, S.; Büchner, B.; Chekhonin, P.; Skrotzki, W.; Nenkov, K.; Hühne, R.; Nielsch, K.; Drechsler, S.-L.; Vadimov, V. L.; Silaev, M. A.; Volkov, P. A.; Eremin, I.; Luetkens, H.; Klauss, H.-H.

In general, magnetism and superconductivity are antagonistic to each other. However, there are several families of superconductors in which superconductivity coexists with magnetism, and a few examples are known where the superconductivity itself induces spontaneous magnetism. The best known of these compounds are Sr2RuO4 and some non-centrosymmetric superconductors. Here, we report the finding of a narrow dome of an s + is' superconducting phase with apparent broken time-reversal symmetry (BTRS) inside the broad s-wave superconducting region of the centrosymmetric multiband superconductor Ba1−xKxFe2As2 (0.7 ≲ x ≲ 0.85). We observe spontaneous magnetic fields inside this dome using the muon spin relaxation (μSR) technique. Furthermore, our detailed specific heat study reveals that the BTRS dome appears very close to a change in the topology of the Fermi surface. With this, we experimentally demonstrate the likely emergence of a novel quantum state due to topological changes of the electronic system

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Permalink: https://www.hzdr.de/publications/Publ-31318
Publ.-Id: 31318


Femtosecond laser produced periodic plasma in a colloidal crystal probed by XFEL radiation

Mukharamova, N.; Lazarev, S.; Meijer, J.-M.; Gorobtsov, O. Y.; Singer, A.; Chollet, M.; Bussmann, M.; Dzhigaev, D.; Feng, Y.; Garten, M.; Huebl, A.; Kluge, T.; Kurta, R. P.; Lipp, V.; Santra, R. J.; Sikorski, M.; Song, S.; Williams, G.; Zhu, D.; Ziaja-Motyka, B.; Cowan, T. E.; Petukhov, A. V.; Vartanyants, I. A.

With the rapid development of short-pulse intense laser sources, studies of matter under extreme irradiation conditions enter further unexplored regimes. In addition, an application of X-ray Free-Electron Lasers (XFELs) delivering intense femtosecond X-ray pulses, allows to investigate sample evolution in IR pump - X-ray probe experiments with an unprecedented time resolution. Here we present a detailed study of the periodic plasma created from the colloidal crystal. Both experimental data and theory modeling show that the periodicity in the sample survives to a large extent the extreme excitation and shock wave propagation inside the colloidal crystal. This feature enables probing the excited crystal, using the powerful Bragg peak analysis, in contrast to the conventional studies of dense plasma created from bulk samples for which probing with Bragg diffraction technique is not possible. X-ray diffraction measurements of excited colloidal crystals may then lead towards a better understanding of matter phase transitions under extreme irradiation conditions.

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Permalink: https://www.hzdr.de/publications/Publ-31317
Publ.-Id: 31317


Polarization tunability in multiferroic DyMn2O5: Influence of Y and Eu co-doping and 3d-4f exchange

Yang, L.; Wang, Changan; Zeng, M.; Hou, Z.; Fan, Z.; Chen, D.; Qin, M.; Lu, X.; Li, Q.; Gao, X.

Coupling effects among spin, charge, and lattice in a strongly correlated system are critical for next generation spintronic and data storage devices. However, the complex effects are elusive and difficult to distinguish their contributions to polarization modulation. Here we tailored the polarization by co-doping of non-magnetic Y and Eu at A-sites in DyMn2O5. The structure, specific heat, magnetism, and ferroelectricity of the polycrystalline Dy1-x(Eu0.24Y0.76)xMn2O5 ceramics were comprehensively explored. Interestingly, the co-doping does not cause lattice distortion of DyMn2O5, and all the ceramics are orthorhombic structures, while the independent Dy3+ spin order and the Dy3+-Mn3+ coupling can be suppressed. With increasing the co-doping content x, the spins related properties associated with the Dy3+-Mn4+-Dy3+ sub-lattice are progressively inhibited, while they keep less disturbance in the Mn3+-Mn4+-Mn3+ block. Moreover, the spin coupling of Dy3+-Mn3+ ions is stronger again the magnetic field than that of Dy3+-Mn3+. Our results enhance the understanding of ferrielectricity in DyMn2O5, and provide a method for controlling the polarization in the multiferroic manganite coexisting 3d and 4f elements.

Keywords: DyMn2O5; Multiferroicity; Ferrielectricity; Manganite

Permalink: https://www.hzdr.de/publications/Publ-31312
Publ.-Id: 31312


Modelling thermal-hydraulic effects of zinc borate deposits in the PWR core after LOCA - Experimental strategies and test facilities

Kästner, W.; Alt, S.; Seeliger, A.; Zacharaias, F.; Harm, U.; Illgen, R.; Hampel, U.; Kryk, H.

The German software tool ATHLET (Analysis of THermohydraulics of Leaks and Transients) is continuously being developed for the simulation of the nuclear power plant behaviour in the event of transients and accidents. The focus of a current joint research project named „ATHLET Modul Zinkborat“ (AZora) is the development and validation of an ATHLET module on the basis of the current state of research on chemical long-term effects according to PWR LOCA. The module is intended to simulate thermohydraulic effects of zinc borate precipitations in the reactor core originating from long-term corrosion processes in the reactor sump during sump recirculation operation after postulated loss-of-coolant accidents in PWR. To develop and validate the sub-models, generic experiments at lab-scale as well as at semi-technical scale are planned to be carried out in unique test facilities. The structure of the module as well as the experimental strategies and the related facilities are described in the article.

Keywords: loss-of-coolant accident; LOCA; pressurized water reactor; nuclear safety research; zinc borate; corrosion; simulation; chemical effects

  • atw - International Journal for Nuclear Power 65(2020)6/7, 341-345

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  • Secondary publication expected from 09.07.2021

Permalink: https://www.hzdr.de/publications/Publ-31310
Publ.-Id: 31310


Numerical simulations of short-circuits appearance in liquid metal batteries

Benard, S.

The mid-term report gives an overview on S. Bénards work at HZDR concerning local short-circuits in liquid metal batteries.

  • Other report
    Paris: École normale supérieure Paris-Saclay, 2020

Permalink: https://www.hzdr.de/publications/Publ-31308
Publ.-Id: 31308


Microfocus X-ray tomography data set of boiling flow in vertical rod bundle with spacer grid at constant heat flux condition

Tas-Köhler, S.; Franz, R.; Boden, S.; Hampel, U.

The test section of the rod bundle experimental facility at HZDR consists of a vertically aligned PMMA channel with an upward flow of the working fluid. The cross-section of the channel is quadratic (inner edge length: 37 mm) and contains nine directly electrically heated rods (material: titanium-alloy, diameter: 10 mm, wall thickness: 0.3 mm) which are arranged in an orthogonal 3 by 3 matrix (rod axis distance: 12.8 mm). Circa 190 mm downstream of the start of the heating zone a 30 mm long spacer for the rods with tilted flow guiding vanes is mounted. These vanes are aimed to increase lateral flow velocities within the subchannels. Working fluid was octafluorocyclobutane (CAS 115-25-3, RC318). The experimental facility is comprehensively instrumented for measurement of flow, temperature and pressure/pressure difference. For non-invasive three-dimensional high-resolution measurement of a temporally averaged volumetric void fraction within the working fluid flowing around the heating rods in the subchannels an X-ray computer tomography measurement system was set up.
The presented dataset contains measurement data of the experimental facility's instrumentation and tomographic void fraction data of experiments with four different configurations of the flow guiding vanes (without vanes, 20°, 29°, 40°) for four different flow velocities between 0.4 m/s and 1.3 m/s at a heat flow density of 85.7 kW/m².
 

 

Keywords: X-Ray Computed Tomography; Phase fraction; Rod bundle; Boiling flow

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-07-08
    DOI: 10.14278/rodare.378

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Permalink: https://www.hzdr.de/publications/Publ-31307
Publ.-Id: 31307


Validierung eines Open-source-Modells für die Simulation von PEM-Brennstoffzellen und Anwendung auf eine luftatmende Brennstoffzelle

Knüpfer, L.

Die vorliegende Arbeit beschäftigt sich mit der dreidimensionalen und mehrphasigen CFD-Simulation von PEM-Brennstoffzellen. Dabei wird die Validierung eines in OpenFOAM implementierten Modells zur Gesamtzellensimulation anhand von drei, von verschiedenen Forschungsgruppen vorgestellten, Experimenten durchgeführt.
Aufbauend auf der Modellvalidierung wird die Anwendbarkeit des Modells auf eine luft-atmende Brennstoffzelle überprüft. In diesem Zusammenhang wird der Einfluss der Orientierung auf die Transportprozesse in einer luftatmenden Brennstoffzelle mit zylindrischer Form untersucht. Dafür wird sowohl die Brennstoffzelle, als auch deren Umgebung beachtet. Die bei variierender Orientierung auftretenden Unterschiede von Naturkonvektion, Temperatur und Massenverteilung von Wasser und Sauerstoff werden dargestellt und diskutiert. Zusätzlich wird auf die Grenzen des verwendeten Modells und mögliche Verbesserungen hingewiesen.

  • Diploma thesis
    TU Dresden, 2020

Permalink: https://www.hzdr.de/publications/Publ-31305
Publ.-Id: 31305


Heavy ion irradiation damage in Zr3(Al0.9Si0.1)C2 MAX phase

Qarra, H. H.; Knowles, K. M.; Vickers, M. E.; Zapata-Solvas, E.; Akhmadaliev, S.

A Zr3(Al0.9Si0.1)C2 MAX phase-based ceramic with 22 wt.% ZrC and 10 wt.% Zr5Si3 has been irradiated with 52 MeV I9+ ions at room temperature, achieving a maximum dose of 8 displacements per atom (dpa). The response of this MAX phase-rich material to irradiation has been studied using scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques. Post-irradiation examination of the material revealed a number of crystalline changes to the MAX phase. At low doses, Zr3(Al0.9Si0.1)C2 maintained a high degree of crystallinity, while at the highest doses, its degree of crystallinity was reduced significantly. A number of radiation-induced phase transformations were observed, including the decomposition of Zr3(Al0.9Si0.1)C2 into ZrC and other phases, and the formation of β-Zr3(Al,Si)C2, a MAX phase with a rearranged stacking sequence. Microstructural examination revealed that the majority of the extended defects in Zr3(Al0.9Si0.1)C2 lie in the (0001) basal planes. Analysis of X-ray diffraction profiles after heat treating the 8 dpa-irradiated material for 1 h at 300 °C and at 600 °C showed that there were only subtle changes to the profiles relative to that of the 8 dpa-irradiated material which had not been heat treated. Overall, the experimental results of this study show that the Zr3(Al0.9Si0.1)C2 MAX phase responds less well to irradiation relative to other MAX phases irradiated with high energy heavy ions at room temperature.

Permalink: https://www.hzdr.de/publications/Publ-31304
Publ.-Id: 31304


Two types of alternating spin-1/2 chains and their field-induced transitions in ε-LiVOPO4

Mukharjee, P. K.; Ranjith, K. M.; Baenitz, M.; Scurschii, I.; Tsirlin, A. A.; Nath, R.

Thermodynamic properties, 31P nuclear magnetic resonance (NMR) measurements, and density-functional band-structure calculations for ε-LiVOPO4 are reported. This quantum magnet features a singlet ground state and comprises two types of alternating spin-1/2 chains that manifest themselves by the double maxima in the susceptibility and magnetic specific heat, and by the two-step magnetization process with an intermediate 1/2-plateau. From thermodynamic data and band-structure calculations, we estimate the leading couplings of J1 ≃ 20 K and J2 ≃ 60 K and the alternation ratios of α1 = J’1/J1 ≃ 0.6 and α2 = J’2/J2 ≃ 0.3 within the two chains, respectively. The zero-field spin gap Δ0/kB ≃ 7.3 K probed by thermodynamic and NMR measurements is caused by the J1-J’1 spin chains and can be closed in the applied field of μ0Hc1 ≃ 5.6 T, giving rise to a field-induced long-range order. The NMR data reveal predominant three-dimensional spin-spin correlations at low temperatures. Field-induced magnetic ordering transition observed above Hc1 is attributed to the Bose-Einstein condensation of triplons in the sublattice formed by the J1-J’1 chains with weaker exchange couplings.

Permalink: https://www.hzdr.de/publications/Publ-31303
Publ.-Id: 31303


Magnetization dynamics and mutual spin-pumping in SAFs

Sorokin, S.; Gallardo, R.; Fowley, C.; Lenz, K.; Titova, A.; Dennehy, G.; Atchenson, G.; Rode, K.; Faßbender, J.; Lindner, J.; Deac, A. M.

Primary data related to the publication in PRB: Article Link.  Pre-release version is available at: Arxiv, ResearchGate.

 

Some of the file are auxiliary or analisys files for faster display of the main results (like .opj, .ods files). Main raw data files are in the archives.

 

 

Keywords: Magnetization dynamics; Spin-pumping; SAFs, SAF; synthetic antiferromagnets; coupled magnetic trilayers; magnetic multilayers; ferromagnetic resonance; electrically-detected ferromagnetic resonance; FMR; ED-FMR; ST-FMR

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2019-12-09
    DOI: 10.14278/rodare.390
    License: CC-BY-4.0

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Permalink: https://www.hzdr.de/publications/Publ-31295
Publ.-Id: 31295


The influence of an applied magnetic field on the self-assembly of magnetic nanogels

Novikau, I. S.; Sanchez Romero, P. A.; Kantorovich, S. S.

Using Langevin dynamics simulations, we investigate the self-assembly of magnetic nanogels in the presence of applied magnetic fields of moderate strength. We find that even weak fields lead to drastic changes in the structure factors of both, the embedded magnetic nanoparticles and of whole nanogel particles. Nanogels assemble by uniting magnetic particle clusters forming inter-gel bridges. At zero field the average amount of such bridges for a pair of nanogels is close to one, whereas even for weak fields it fastly doubles. Rapid growth of cluster size at low values of the applied field is followed by a broad region of slow increase, caused by the mechanical constraints imposed the polymer matrix. The influence of the latter manifests itself in both, the slow growth of the magnetisation curve at intermediate fields and the slow decay of the total Zeeman energy.

Keywords: Magnetic nanogels; Self-assembly; Molecular dynamics

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  • Secondary publication expected from 01.06.2021

Permalink: https://www.hzdr.de/publications/Publ-31294
Publ.-Id: 31294


Diffusion of single active-dipolar cubes in applied fields

Kaiser, M.; Martinez, Y.; Schmidt, A. M.; Sanchez Romero, P. A.; Kantorovich, S. S.

“Active matter” refers to a class of out-of-equilibrium systems whose ability to transform environmental energy to kinetic energy is sought after in multiple fields of science and at very different length scales. At microscopic scales, an important challenge lies in overpowering the particles reorientation due to thermal fluctuations, especially in nano-sized systems, to create non-random, directed motion, needed for a wide range of possible applications. In this article, we employ molecular dynamics simulations to show that the diffusion of a self-propelling dipolar nanocube can be enhanced in a pre-defined direction with the help of a moderately strong applied magnetic field, overruling the effect of the thermal fluctuations. Furthermore, we show that the direction of diffusion is given by the orientation of the net internal magnetisation of the cube. This can be used to determine experimentally the latter in synthetically crafted active cobalt ferrite nanocubes.

Keywords: Active matter; Magnetic cubes; Molecular dynamics

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  • Secondary publication expected from 15.04.2021

Permalink: https://www.hzdr.de/publications/Publ-31293
Publ.-Id: 31293


Measuring FORCs diagrams in computer simulations as a mean to gain microscopic insight

Dobroserdova, A. B.; Sanchez Romero, P. A.; Shapochkin, V. E.; Smagin, D. A.; Zverev, V. S.; Odenbach, S.; Kantorovich, S. S.

FORCs (first-order reversal curves) diagrams prove to be an efficient experimental technique to investigate magnetic interactions in complex systems. In experiments, as a rule, it is difficult to relate actual microstructural changes to the evolution of FORCs diagrams. Here, using Molecular Dynamics simulations, we calculate FORCs for two simple models of a magnetic elastomer. The simplicity of these models allows to relate directly both, the rigidity of the matrix and the magnetoelastic coupling to the shape and intensity of FORCs diagrams.

Keywords: FORC Molecular dynamics; Magnetic elastomers; Magneto-elastic coupling

Permalink: https://www.hzdr.de/publications/Publ-31292
Publ.-Id: 31292


Unknotting of quasi-two-dimensional ferrogranular networks by in-plane homogeneous magnetic fields

Sanchez Romero, P. A.; Miller, J.; Kantorovich, S. S.; Richter, R.

Our ongoing research addresses, by means of experiments and computer simulations, the aggregation process that takes place in a shaken granular mixture of glass and magnetized ferrous alloy beads when the shaking amplitude is suddenly decreased. After this quenching, the magnetized beads form a transient network that coarsens in time into compact clusters, following a viscoelastic phase separation. Here we focus on the quasi-two-dimensional case, analyzing in computer simulations the effects of a magnetic field parallel to the system plane. Our results evidence that the field drastically changes the structure of the forming network: chains and elongated clusters parallel to the field are favored whereas perpendicular connecting structures tend to be suppressed, leading to the unknotting of the networks which are observed at zero field. Importantly, we found that moderate field strengths lead to the formation of larger clusters at intermediate time intervals than in the case of weak and strong fields. Moreover, the latter tend to limit the overall growth of the clusters at longer time scales. These results may be relevant in different systems governed by similar magnetically driven aggregation processes as, for example, in the formation of iron-rich planetesimals in protoplanetary discs or for magnetic separation systems.

Keywords: Ferrogranulate mixture; Field induced network unknotting; Susceptible dipolar hard spheres; Langevin dynamics simulations; Viscoelastic phase separation; Transient network

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  • Secondary publication expected from 01.04.2021

Permalink: https://www.hzdr.de/publications/Publ-31291
Publ.-Id: 31291


The influence of crosslinkers and magnetic particle>distribution along the filament backbone on the magnetic properties of supracolloidal linear polymer-like chains

Mostarac, D.; Vaughan, L.; Sanchez Romero, P. A.; Kantorovich, S. S.

Diverse polymer crosslinking techniques allow the synthesis of linear polymer-like structures whose monomers are colloidal particles. In the case where all or part of these colloidal particles are magnetic, one can control the behaviour of these supracolloidal polymers, known as magnetic filaments (MFs), by applied magnetic fields. However, the response of MFs strongly depends on the crosslinking procedure. In the present study, we employ Langevin dynamics simulations to investigate the influence of the type of crosslinking and the distribution of magnetic particles within MFs on their response to an external magnetic field. We found that if the rotation of the dipole moment of particles is not coupled to the backbone of the filament, the impact of the magnetic content is strongly decreased.

Keywords: Supracolloidal magnetic polymers; Magnetisation; Crosslinking methods; Langevin dynamics simulations

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  • Secondary publication expected from 01.03.2021

Permalink: https://www.hzdr.de/publications/Publ-31290
Publ.-Id: 31290


Suspensions of magnetic nanogels at zero field: Equilibrium structural properties

Novikau, I. S.; Minina, E. S.; Sanchez Romero, P. A.; Kantorovich, S. S.

Magnetic nanogels represent a cutting edge of magnetic soft matter research due to their numerous potential applications. Here, using Langevin dynamics simulations, we analyse the influence of magnetic nanogel concentration and embedded magnetic particle interactions on the self-assembly of magnetic nanogels at zero field. For this, we calculated radial distribution functions and structure factors for nanogels and magnetic particles within them. We found that, in comparison to suspensions of free magnetic nanoparticles, where the self-assembly is already observed if the interparticle interaction strength exceeds the thermal fluctuations by approximately a factor of three, self-assembly of magnetic nanogels only takes place by increasing such ratio above six. This magnetic nanogel self-assembly is realised by means of favourable close contacts between magnetic nanoparticles from different nanogels. It turns out that for high values of interparticle interactions, corresponding to the formation of internal rings in isolated nanogels, in their suspensions larger magnetic particle clusters with lower elastic penalty can be formed by involving different nanogels. Finally, we show that when the self-assembly of these nanogels takes place, it has a drastic effect on the structural properties even if the volume fraction of magnetic nanoparticles is low.

Keywords: Magnetic nanogels; Magnetic self-assembly; Langevin dynamics; Structure factor

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  • Secondary publication expected from 15.03.2021

Permalink: https://www.hzdr.de/publications/Publ-31289
Publ.-Id: 31289


The structure of clusters formed by Stockmayer supracolloidalmagnetic polymers

Kantorovic, S. S.; Sanchez Romero, P. A.; Pyanzina, E. S.; Novak, E. V.

Unlike Stockmayer fluids, that prove to undergo gas-liquid transition on cooling, the system of dipolar hard or soft spheres without any additional central attraction so far has not been shown to have a critical point. Instead, in the latter, one observes diverse self-assembly scenarios. Crosslinking dipolar soft spheres into supracolloidal magnetic polymer-like structures (SMPs) changes the self-assembly behaviour. Moreover, aggregation in systems of SMPs strongly depends on the constituent topology. For Y- and X-shaped SMPs, under the same conditions in which dipolar hard spheres would form chains, the formation of very large loose gel-like clusters was observed (E. Novak et al., J. Mol. Liq. 271, 631 (2018)). In this work, using molecular dynamics simulations, we investigate the self-assembly in suspensions of four topologically different SMPs --chains, rings, X and Y-- whose monomers interact via Stockmayer potential. As expected, compact drop-like clusters are formed by SMPs in all cases if the central isotropic attraction is introduced, however, their shape and internal structure turn out to depend on the SMPs topology.

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  • Secondary publication expected from 23.12.2020

Permalink: https://www.hzdr.de/publications/Publ-31288
Publ.-Id: 31288


Atomistic simulation of PDADMAC/PSS oligoelectrolyte multilayers: overall comparison of tri- and tetra-layer systems

Sanchez Romero, P. A.; Vögele, M.; Smiatek, J.; Qiao, B.; Sega, M.; Holm, C.

By employing large-scale molecular dynamics simulations of atomistically resolved oligoelectrolytes in aqueous solutions, we study in detail the first four layer-by-layer deposition cycles of an oligoelectrolyte multilayer made of poly(diallyl dimethyl ammonium chloride)/poly(styrene sulfonate sodium salt) (PDADMAC/PSS). The multilayers are grown on a silica substrate in 0.1 M NaCl electrolyte solutions and the swollen structures are then subsequently exposed to varying added salt concentration. We investigated the microscopic properties of the films, analyzing in detail the differences between three- and four-layer systems. Our simulations provide insights into the early stages of growth of a multilayer, which are particularly challenging for experimental observations. We found rather strong complexation of the oligoelectrolytes, with fuzzy layering of the film structure. The main charge compensation mechanism is for all cases intrinsic, whereas extrinsic compensation is relatively enhanced for the layer of the last deposition cycle. In addition, we quantified other fundamental observables of these systems, such as the film thickness, water uptake, and overcharge fractions for each deposition layer.

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  • Secondary publication expected from 04.11.2020

Permalink: https://www.hzdr.de/publications/Publ-31286
Publ.-Id: 31286


Itinerant metamagnetic transition in the ferromagnet LuCo3 induced by high field: Instability of the 3d-electron subsystem

Neznakhin, D. S.; Radzivonchik, D. I.; Gorbunov, D.; Andreev, A. V.; Sebek, J.; Lukoyanov, A. V.; Bartashevich, M. I.

LuCo3 is an itinerant ferromagnet whose magnetic properties strongly depend on the position of the 3d electronic states relative to the Fermi level. Here, we report on the magnetization of a LuCo3 single crystal in pulsed magnetic fields up to 58 T. We find a field-induced phase transition just below 50 T from a low-spin to a high-spin state. The transition shows a pronounced anisotropy of the magnetization jump and hysteresis. A series of ab initio calculations based on the density functional theory show that the transition is due to a significant change in the occupancies of the Co 3d electronic states. At the same time, some features in the majority spin density of the Co 3d states are slightly modified and pass through the Fermi level when the spin state is changed, which leads to the instability of the 3d-electron subsystem. Thereby, the applied magnetic field causes a significant redistribution in the majority and minority spin states in the Co 3d subsystem, which results in the sharp change in the magnetization.

Permalink: https://www.hzdr.de/publications/Publ-31284
Publ.-Id: 31284


Enhanced magnetocaloric effect in distilled terbium and emergence of novel properties after severe plastic deformation

Tereshina-Chitrova, E. A.; Korneeva, Y. V.; Ozherelkov, D. Y.; Dolezal, P.; Tereshina, I. S.; Kaminskaya, T. P.; Gorbunov, D.; Dobatkin, S. V.; Minarik, P.

We report the magneto-structural and magnetocaloric properties study of Tb purified by distillation and further processed by severe plastic deformation (SPD). Both parent and the SPD-processed Tb contain nanosized structural elements and have a very pronounced (00 l ) texture. We observe an improved magnetocaloric effect (MCE) in the distilled nanocrystalline Tb while novel properties emerge in the sample after severe plastic deformation. The latter demonstrates zero thermal expansion over a wide temperature range while its MCE vanishes. We show that the absolutely new physical properties in Tb result from the structural transformation and modification of magnetic interactions.

Permalink: https://www.hzdr.de/publications/Publ-31283
Publ.-Id: 31283


Intrinsic plasticity of silicon nanowire neurotransistors: plots of the figures 1-2

Baraban, L.

Data and Figures supporting the publication

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-07-01
    DOI: 10.14278/rodare.388
    License: CC-BY-4.0

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Permalink: https://www.hzdr.de/publications/Publ-31280
Publ.-Id: 31280


Development and In Vivo Application of a Water-Soluble Anticancer Copper Ionophore System Using a Temperature-Sensitive Liposome Formulation

Gaál, A.; Garay, T. M.; Horváth, I.; Máthé, D.; Szöllösi, D.; Veres, D. S.; Mbuotidem, J.; Kovacs, T.; Tóvári, J.; Bergmann, R.; Streli, C.; Szakács, G.; Mihály, J.; Varga, Z.; Szoboszlai, N.

Liposomes containing copper and the copper ionophore neocuproine were prepared and characterized for in vitro and in vivo anticancer activity. Thermosensitive PEGylated liposomes were prepared with di_erent molar ratios of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) and hydrogenated soybean phosphatidylcholine (HSPC) in the presence of copper(II) ions. Optimal, temperature dependent drug release was obtained at 70:30 DPPC to HSPC weight ratio. Neocuproine (applied at 0.2 mol to 1 mol phospholipid) was encapsulated through a pH gradient while using unbuffered solution at pH 4.5 inside the liposomes, and 100 mM HEPES bu_er pH 7.8 outside the liposomes. Copper ions were present in excess, yielding 0.5 mM copper-(neocuproine)2 complex and 0.5 mM free copper. Pre-heating to 45 °C increased the toxicity of the heat-sensitive liposomes in short-term in vitro experiments, whereas at 72 h all investigated liposomes exhibited similar in vitro toxicity to the copper(II)-neocuproine complex (1:1 ratio). Thermosensitive liposomes were found to be more effective in reducing tumor growth in BALB/c mice engrafted with C26 cancer cells, regardless of the mild hyperthermic treatment. Copper uptake of the tumor was verified by PET/CT imaging following treatment with [64Cu]Cu-neocuproine liposomes. Taken together, our results demonstrate the feasibility of targeting a copper nanotoxin that was encapsulated in thermosensitive liposomes containing an excess of copper.

Keywords: eocuproine; themosensitive liposomal formulation; mild hyperthermia; copper nanotoxin; MRPS; in vivo antitumor effect

Permalink: https://www.hzdr.de/publications/Publ-31278
Publ.-Id: 31278


Heisenberg limit for detecting vacuum birefringence

Ahmadiniaz, N.; Cowan, T.; Sauerbrey, R.; Schramm, U.; Schlenvoigt, H.-P.; Schützhold, R.

Quantum electrodynamics predicts the vacuum to behave as a nonlinear medium, including effects such as birefringence. However, for experimentally available field strengths, this vacuum polarizability is extremely small and thus very hard to measure. In analogy to the Heisenberg limit in quantum metrology, we study the minimum requirements for such a detection in a given strong field (the pump field). Using a laser pulse as the probe field, we find that its energy must exceed a certain threshold depending on the interaction time. However, a detection at that threshold, i.e., the Heisenberg limit, requires highly nonlinear measurement schemes--while for ordinary linear-optics schemes, the required energy (Poisson or shot noise limit) is much larger. Finally, we discuss several currently considered experimental scenarios from this point of view.

Keywords: Quantum Electrodynamics; Vacuum birefringence; Heisenberg limit

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Permalink: https://www.hzdr.de/publications/Publ-31277
Publ.-Id: 31277


Status of the STM-FPGA-DAQ HLS-Cores for LaBr Peak Detection and Zero Suppression

Knodel, O.

Brief overview and status of the STM-FPGA-DAQ HLS-Cores for LaBr peak detection, moving window deconvolution and zero suppression

Keywords: Data Management; DAQ; FPGA; Mu2e

  • Invited lecture (Conferences) (Online presentation)
    Mu2e Collaboration Meeting, STM Workshop, 16.06.2020, Online, Online

Permalink: https://www.hzdr.de/publications/Publ-31275
Publ.-Id: 31275


Interprofessionelle Kooperation: Bedarf und Komplexizität bei prospektiv-nuklearmedizinischen Studien am Beispiel des DKTK-Multicenter-Trials mit [68Ga]Ga-PSMA-11

Zippel, C.; Neels, O.; Biedenstein, S.; Giesel, F. L.; Kopka, K.

Ziel/Aim: Um neue PET-Tracer in die Patientenversorgung überführen zu können, werden in der nuklearmedizinischen Forschung zunehmend prospektiv-klinische Studien mit den vielversprechendsten Radioliganden initiiert. Damit diese Studien möglichst effizient und effektiv durchgeführt werden können, bedarf es der möglichst engen Kooperation und Kommunikation von Expert*innen aus verschiedenen Berufsgruppen.

Methodik/Methods: Wir beleuchten am Beispiel der Multicenter-Studie „Ga-68-PSMA-11 in Hochrisiko-Prostatakrebs“ der Phasen-I/-II, welche wesentlichen Professionen aus forschender Klinik, Wirkstoffherstellung und Verwaltung bei der Planung, Vorbereitung und Durchführung prospektiv-nuklearmedizinischer Studien involviert sein können und welche Aufgaben diese zur Studienverwirklichung wahrnehmen. Darauf aufbauend leiten wir organisatorische Maßnahmen ab, durch die die interprofessionelle Kooperation bei prospektiven Bildgebungsstudien (auch über mehrere Prüfzentren) gefördert werden kann.

Ergebnisse/Results: In die Beispielstudie sind im engeren fachlichen Kreis Mediziner aus Nuklearmedizin/Urologie/Pathologie, MTA-Rs, Studienassistenten, Radiochemiker/-pharmazeuten, BTA/CTA, MTA und Gesundheits-/Krankenpfleger involviert. Im weiteren fachlichen Kreis sind ferner Strahlenschutzbeauftragte, Qualitätsmanager, klinische Monitore, Juristen, Datenschutzbeauftragte, Projektmanager und Studienkoordinatoren eingebunden, und dies jeweils an bis zu elf Prüfzentren in Deutschland, Österreich und der Schweiz.

Schlussfolgerungen/Conclusions: Interprofessionelle Kooperation ist für die Durchführung prospektiv-nuklearmedizinischer Studien essentiell. Hierzu bedarf es u.a. der grundlegenden Bereitschaft, sich in andere (Tätigkeits-)Rollen hineinzuversetzen und über Professionsgrenzen hinaus kooperieren zu wollen, ausreichend Zeit zum gegenseitigen Austausch, Fähigkeit/Fertigkeiten zum berufsübergreifenden Projektmanagement und eine integrale Betrachtung benötigter Expertisen mit Stärkung professionsübergreifender Kommunikation insbesondere über die Leitungsebene.

  • Lecture (Conference) (Online presentation)
    58. DGN-Jahrestagung 2020, 06.-09.07.2020, Leipzig, Deutschland
    DOI: 10.1055/s-0040-1708427

Permalink: https://www.hzdr.de/publications/Publ-31274
Publ.-Id: 31274


GMP Requirements for a Clinical Trial with 68Ga-PSMA-11 - Experience from a Multi-Centre Trial

Neels, O.

Without abstract

  • Invited lecture (Conferences)
    Annual Congress of the European Association of Nuclear Medicine, 15.-19.10.2016, Barcelona, Spanien
    DOI: 10.1007/s00259-016-3484-4

Permalink: https://www.hzdr.de/publications/Publ-31273
Publ.-Id: 31273


Molecular Imaging of Prostate Cancer: A direct comparison of the preclinical characteristics of [18F]DCFPyL and [18F]PSMA-1007 and the impact of glutamic acids on [18F]PSMA-1007

Roscher, M.; Remde, Y.; Schäfer, M.; Bauder-Wüst, U.; Giesel, F.; Neels, O.; Cardinale, J.; Kopka, K.

Aim: For the imaging of PSMA-positive prostate cancer, several fluorine-18 (18F)-labelled compounds have been developed and translated into the clinics. Next to a clinical study comparing the tracer-specific characteristics of [18F]DCFPyL and [18F]PSMA-1007 intra-individually(1), a direct comparison of their preclinical characteristics has only recently been published(2). In this work, the importance of glutamic acids in the structure of [18F]PSMA-1007 is further elucidated using derivatives with none to three glutamic acids (Glu), respectively. Furthermore, [18F]DCFPyL and [18F]PSMA-1007 are evaluated regarding their preclinical characteristics using the in vitro and in vivo methods established at DKFZ Heidelberg, Germany. Materials and Methods: The precursors for radiofluorination containing different amino acid linkers (0-3 Glu) were synthesized by means of solid phase chemistry. The radiolabeling of [18F]PSMA-1007, its derivatives, and [18F]DCFPyL were performed prior to each experiment as described(3,4). The binding affinities of non-radioactive reference compounds were determined by competitive binding assays against [68Ga]Ga-PSMA-10 in LNCaP cells. The internalization of the respective radioligands in LNCaP cells was compared. Biodistribution and pharmacokinetics were evaluated in vivo in LNCaP-tumor bearing BALB/c Nude mice using μPET. Results: The Glu variation in the linker structure resulted in similar binding affinities (Ki 3-14 nM) whereby the insertion of three Glu showed the highest Ki values. Internalization assays revealed that the insertion of Glu influences the internalization rate, whereby the insertion of two Glu ([18F]PSMA-1007) leads to the highest internalization rate (54.04±13.7%) in a total range between 27.3±3% to 54±13.7%. In comparison to [18F]PSMA-1007, a higher proportion of [18F]DCFPyL remains cell surface bound; only 27.83 ± 4.31% of the radiotracer is internalized. [18F]DCFPyL also has a slightly lower binding affinity (18.02±9.63 nM). μPET imaging showed outstanding imaging properties, especially of [18F]DCFPyL and [18F]PSMA-1007. In mice, the liver uptake is reduced by introduction of Glu linkers. The data will be analysed more detailed soon. Conclusion: Comparative cell experiments revealed a high binding affinity for all tracers and the highest internalization rate for [18F]PSMA-1007. The insertion of Glu in the linker structure plays an important role in pharmacokinetics due to the decreased lipophilicity of the respective radiotracer. Especially [18F]DCFPyL and [18F]PSMA-1007 are of excellent imaging quality. Their apparent non-inferiority is currently under further assessment in clinical trials. References: (1) Giesel F et al (2017): JNM, doi: 10.2967/jnumed.117.204669. (2) Robu S et al (2018): EJNMMI Res., 8(1):30. (3) Cardinale J et al. (2017): JNM, 58(3):425-431. (4) Chen Y et al. (2011): Clin Cancer Res., 17(24):7645-53.

  • Lecture (Conference)
    Annual Congress of the European Association of Nuclear Medicine, 13.-17.10.2018, Düsseldorf, Deutschland
    DOI: 10.1007/s00259-018-4148-3

Permalink: https://www.hzdr.de/publications/Publ-31272
Publ.-Id: 31272


Initiation Of A Prospective Clinical Multicentre Trial With Local Production Of A Short-Lived PSMA-PET Radiopharmaceutical In The D-A-CH-Region: Chances And Experiences

Neels, O.; Zippel, C.; Giesel, F. L.; Kopka, K.

Aim/Introduction: The development of innovative radiotracers targeting PSMA for non-invasive imaging of prostate cancer and successive treatment results in an increasing number of multicentre clinical trials using the most promising PSMA ligand candidates. For prospective studies with short-lived radiopharmaceuticals like [68Ga]Ga-PSMA-11, a regulatory and country-specific structure has to be established before recruitment of patients is possible. This structure allows the decentralized manufacturing of the investigational medicinal product (IMP) according to Good Manufacturing (GMP) and subsequent implementation of the respective tracer compliant with Good Clinical Practice (GCP). Materials and Methods: For the multicenter clinical trial (phases-I/-II) ,,Ga-68-PSMA-11 in high-risk prostate cancer“ (NCT03362359) within DKTK a harmonized decentralized radiotracer production in multiple radiopharmacies has been set up for the very first time in the German speaking Radiopharmacy/Nuclear Medicine Community. In this prospective clinical study Nuclear Medicine physicians, radiopharmacists, urologists, pathologists and study related experts like lawyers and study nurses out of eleven study sites within the so-called D-A-CH region (Germany-Austria-Switzerland) have been involved. The basis for the accurately specified radioactive IMP manufacturing procedure was defined by EU-GMP requirements plus national standards (e.g. Medicinal Products Act and Radiation Protection Law). Results: For the recruiting study sites the required allowances, e.g. manufacturing authorization from local authorities as well as approval from ethics committees and national regulatory bodies such as BfS and BfArM in Germany, BASG in Austria as well as BAG and Swissmedic in Switzerland, have been obtained. The challenge of manufacturing a short-lived radiopharmaceutical at each of the participating geographically different sites with identical specification by adaption of production and quality control processes and parameters according to the IMP dossier (IMPD) during the starting phase of the clinical trial under a centralized quality assurance management has been achieved. Conclusion: The initiation and establishment of a multicentre clinical trial including the manufacturing of a short-lived radiopharmaceutical IMP across local study sites is very complex, but manageable. In view of the high European and national regulatory and legal burdens and the number of involved partners it is feasible in a defined time frame. Based on the achieved structures, the decentralized manufacture of novel short-lived radiopharmaceuticals can be established in the D-A-CH region and even on a European level for further investigator initiated multicentre clinical trials. We estimate our experiences important for the development of the field Nuclear Medicine at the national and international level taking into account the new EU regulation No 536/2014. References: None.

  • Poster
    Annual Congress of the European Association of Nuclear Medicine, 12.-16.10.2019, Barcelona, Spanien
    DOI: 10.1007/s00259-019-04486-2

Permalink: https://www.hzdr.de/publications/Publ-31271
Publ.-Id: 31271


Too many regulations

Neels, O.

Without abstract

  • Invited lecture (Conferences)
    Annual Congress of the European Association of Nuclear Medicine, 12.-16.10.2019, Barcelona, Spanien
    DOI: 10.1007/s00259-019-04486-2

Permalink: https://www.hzdr.de/publications/Publ-31270
Publ.-Id: 31270


Supplementary Video sets for the publication

Baraban, L.

6 supplementary videos

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-06-29
    DOI: 10.14278/rodare.384
    License: CC-BY-4.0

Downloads:

Permalink: https://www.hzdr.de/publications/Publ-31268
Publ.-Id: 31268


Intrinsic plasticity of silicon nanowire neurotransistors for dynamic memory and learning functions

Baek, E.; Ranjan Das, N.; Vittorio Cannistraci, C.; Rim, T.; Santiago Cañón Bermúdez, G.; Nych, K.; Cho, H.; Kim, K.; Baek, C.-K.; Makarov, D.; Tetzlaff, R.; Chua, L.; Baraban, L.; Cuniberti, G.

Neuromorphic architectures merge learning and memory functions within a single unit cell and in a neuron-like fashion. Research in the field has been mainly focused on the plasticity of artificial synapses. However, the intrinsic plasticity of the neuronal membrane is also important in the implementation of neuromorphic information processing. Here we report a neurotransistor made from a silicon nanowire transistor coated by an ion-doped sol–gel silicate film that can emulate the intrinsic plasticity of the neuronal membrane. The neurotransistors are manufactured using a conventional complementary metal–oxide–semiconductor process on an 8-inch (200 mm) silicon-on-insulator wafer. Mobile ions allow the film to act as a pseudo-gate that generates memory and allows the neurotransistor to display plasticity. We show that multiple pulsed input signals of the neurotransistor are non-linearly processed by sigmoidal transformation into the output current, which resembles the functioning of a neuronal membrane. The output response is governed by the input signal history, which is stored as ionic states within the silicate film, and thereby provides the neurotransistor with learning capabilities.

Related publications

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  • Secondary publication expected from 25.11.2020

Permalink: https://www.hzdr.de/publications/Publ-31265
Publ.-Id: 31265


Nanosensors-Assisted Quantitative Analysis of Biochemical Processes in Droplets

Belyaev, D.; Schütt, J.; Ibarlucea, B.; Rim, T.; Baraban, L.; Cuniberti, G.

Here, we present a miniaturized lab-on-a-chip detecting system for an all-electric and label-free analysis of the emulsion droplets incorporating the nanoscopic silicon nanowires-based field-effect transistors (FETs). We specifically focus on the analysis of β-galactosidase activity, which is an important enzyme in the glycolysis metabolic pathway. Furthermore, the efficiency of the synthesis and action of β-galactosidase can be one of the markers for several diseases, eg., cancer, hyper/hypoglycemia, cell senescence, or other disruptions in cell functioning. We measure the reaction and reaction kinetics-associated shift of the source-to-drain current I sd in the system, which is caused by the change of the ionic strength of the microenvironment. With these results, we demonstrate that the ion-sensitive FETs are able to sense the interior of the aqueous reactors; thus, the conjunction of miniature nanosensors and droplet-based microfluidic systems conceptually opens a new route toward a sensitive, optics-less analysis of biochemical processes.

Permalink: https://www.hzdr.de/publications/Publ-31264
Publ.-Id: 31264


Experimental control of laser proton acceleration beyond 50 MeV

Ziegler, T.; Bernert, C.; Bock, S.; Brack, F.-E.; Cowan, T.; Garten, M.; Gaus, L.; Gebhardt, R.; Helbig, U.; Irman, A.; Kiriyama, H.; Kluge, T.; Kraft, S.; Kroll, F.; Metzkes-Ng, J.; Nishiuchi, M.; Obst-Hübl, L.; Püschel, T.; Rehwald, M.; Schlenvoigt, H.-P.; Schramm, U.; Zeil, K.

We report on the ongoing plasma accelerator development at the HZDR, moving from plasma-acceleration studies towards real plasma-accelerators that can be controlled and applied in the lab.
We show experimental investigations of proton acceleration from laser-irradiated solid foils with the DRACO PW laser, where highest proton cut-off energies were achieved for temporal pulse shape parameters well different from that of a Fourier transform limited (FTL) pulse. Controlled spectral phase modulation of the driver laser by means of an acousto-optic programmable dispersive filter enabled us to manipulate the temporal laser pulse shape and to study the effect on proton acceleration from thin foil targets. The results show that short and asymmetric pulses generated by positive third order dispersion values are favourable for proton acceleration and can lead to maximum energies of 60 MeV for thin plastic foils. Assuming appropriate control of the spectral phase of the laser and comparable temporal contrast conditions, we believe that the presented method can be universally applied to improve the proton acceleration performance using any other laser system operated in the PW regime.

  • Lecture (Conference) (Online presentation)
    6. Annual Matter and Technology Meeting, 17.-18.06.2020, Jülich, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-31263
Publ.-Id: 31263


Synthesis, characterization and evaluation of 68Ga labelled monomeric and dimeric quinazoline derivatives of the HBED-CC chelator targeting the epidermal growth factor receptor

Liolios, C.; Shegani, A.; Roupa, I.; Kiritsis, C.; Makarem, A.; Paravatou-Petsotas, M.; Pelecanou, M.; Bouziotis, P.; Papadopoulos, M.; Kopka, K.; Pirmettis, I.

Tyrosine kinase (TK) receptors including epidermal growth factor receptors (EGFRs) are known to be overexpressed in a wide variety of solid tumors associated with poor prognosis. The HBED-CC chelator N,N′-bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-N,N′-diacetic acid 1 was coupled via one or both its propionic acid moieties with the quinazoline EGFR-TK inhibiting pharmacophore 4-amino-N-(4-((3-bromophenyl)amino)quinazolin-6-yl)butanamide 3 resulting in either a monomeric 4 or a dimeric 5 species. Ligands 4 and 5 reacted with Ga3+ generating the corresponding complexes Ga4 and Ga5. Both ligands and complexes were characterized with mass spectrometry and NMR spectroscopy and evaluated in vitro with MTT assays in A431 cells, where they showed IC50 values in the range 51.6 to 68.8 μM. Labeling of ligands 4 and 5 with the PET radionuclide 68Ga was quantitative and resulted in tracers [68Ga]Ga4 and [68Ga]Ga5 with radiochemical purities greater than 98%, which were also characterised by comparative RP-HPLC studies with Ga4 and Ga5 respectively. Radiotracers [68Ga]Ga4 and [68Ga]Ga5 were stable (in tact tracer over 98%) in the reaction mixture (120 min) and in human serum (30 min). Both tracers were evaluated in vivo with biodistribution experiments in SCID mice bearing A431 tumors presenting tumor uptake of 1.34 for [68Ga]Ga4 and 1.01 %ID/g for [68Ga]Ga5 at 5 min, which was slightly decreased at 60 min p.i. and then remained stable until 120 min p.i. To the best of our knowledge, this is the first report of monomeric and dimeric quinazoline conjugates with the chelator HBED-CC, which can serve as a basis for further development of EGFR-TKI targeting tracers.

Keywords: Epidermal growth factor tyrosine kinase (EGFR-TK); tyrosinekinase inhibitors (TKIs); Quinazoline Gallium complexes; 68Ga; HBED-CC

Permalink: https://www.hzdr.de/publications/Publ-31262
Publ.-Id: 31262


The state of trace elements (In, Cu, Ag) in sphalerite studied by X-ray absorption spectroscopy of synthetic minerals

Trofimov, N. D.; Trigub, A. L.; Tagirov, B. R.; Filimonova, O. N.; Evstigneeva, P. V.; Chareev, D. A.; Kvashnina, K. O.; Nickolsky, M. S.

The oxidation state and local atomic environment of admixtures of In, Cu, and Ag in synthetic sphalerite crystals were determined by X-ray absorption spectroscopy (XAS). The sphalerite crystals doped with In, Cu, Ag, In-Cu, and In-Ag were synthesized by means of gas transport, salt flux, and dry synthesis techniques and studied by X-ray absorption near edge structure (XANES)/ X-ray absorption fine structure (EXAFS) spectroscopy. The spectra were recorded at Zn, In, Ag, and Cu K-edges. In all studied samples In3+ replaces Zn in the structure of sphalerite. The In-S distance increases by 0.11-0.12 Å in the 1st coordination shell, 0.05-0.08 Å in the 2st shell, and 0.01-0.04 Å in the 3rd shell in comparison with Zn-S distance in pure sphalerite. The substitution scheme 3Zn2+↔2In3++□, where □ is a Zn vacancy, is realized in the In-bearing sphalerite in the absence of other dopants. In the presence of In the oxidation state of Cu and Ag is 1+, both the metals can form isomorphous solid solution where they substitute for Zn according to the coupled substitution scheme 2Zn2+↔Me++In3+. The 1st coordination shell of Cu slightly contracts compared to the pure sphalerite (RCu-S = 2.30-2.31 Å vs RZn-S = 2.34 Å), whereas the 1st shell of Ag expands (RAg-S = 2.46 Å) and is equal to the In-S distance in the sphalerite solid solution. These data, combined with results for In-Au-bearing sphalerites (Filimonova et al., Mineral. Mag. 2019, 83, 435–451), show that the Me-S distances in the 1st coordination shell in the solid solution state are correlated with the ionic radii and increase in the order of Cu < Ag < Au. The distortion of the atomic structure increases in the same order. The distant (2nd and 3rd) coordination shells of Cu and Ag in sphalerite are splitted into two subshells, and the splitting is more pronounced for Ag. The dominant form of Au, as determined in Fillimonova et al. (2019), is the Au2S-like inclusions with only traces of the solid solution Au. Analysis of the EXAFS spectra, coupled with the results of DFT simulations showed that the In-In and Me+-In3+ clustering is absent when the metals present in the sphalerite solid solution. Therefore, all studied admixtuires (In, Cu, Ag), as well as Au, are randomly distributed in the matrix of sphalerite, where the concentration of the elements in the “invisible” form can reach a few tens wt.%.

Permalink: https://www.hzdr.de/publications/Publ-31260
Publ.-Id: 31260


Fingerprinting mean composition of lithium polysulfide standard solutions by applying high energy resolution fluorescence detected X-ray Absorption Spectroscopy

Robba, A.; Barchasza, C.; Bučar, K.; Petric, M.; Žitnik, M.; Kvashnina, K.; Vaughan, G. B. M.; Bouchet, R.; Alloin, F.; Kavčič, M.

In a lithium/sulfur (Li/S) battery, the reduction of sulfur during discharge involves a particular mechanism, where the active material successively dissolves into the electrolyte to form lithium polysulfide intermediate species (Li2Sx), with x being a function of the state of charge. In this work, sulfur K-edge Resonant Inelastic X-ray Scattering measurements were performed for the characterization of different Li2Sx polysulfide standard solutions. High Energy Resolution Fluorescence Detected X-ray Absorption Spectroscopy allowed clear separation the pre-edge absorption peak corresponding to terminal sulfur atoms from the main absorption peak due to internal atoms, and to evaluate quantitatively the evolution of the peak area ratio as a function of the polysulfide chain length. Results of this experimental work demonstrate that the normalized area of the pre-edge is a reliable fingerprint of Li2Sx mean chain length in agreement with recent theoretical predictions. As a perspective, this work confirms that operando HERFD XAS can be used to differentiate mean polysulfide composition, which is key issue in the characterization of Li/S cells.

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  • Secondary publication expected from 25.06.2021

Permalink: https://www.hzdr.de/publications/Publ-31259
Publ.-Id: 31259


Study of nanoscopic porosity in black metals by positron annihilation spectroscopy

Melikhova, O.; Cížek, J.; Hruška, P.; Liedke, M. O.; Butterling, M.; Wagner, A.; Novotný, M.; More-Chevalier, J.

Black and smooth Al films were characterized by the variable energy positron annihilation spectroscopy (VEPAS). It was found that in smooth films positronium (Ps) is formed on the surface only while in black metal films, it is formed also in nanoscopic pores inside the film. The mean pore size increases from the substrate to the surface due to increasing film roughness.

Keywords: positron annihilation spectroscopy; positron annihilation lifetime spectroscopy; black metals; Positronium

Permalink: https://www.hzdr.de/publications/Publ-31258
Publ.-Id: 31258


A secret luminescence killer in deepest QWs of InGaN/GaN multiple quantum well structures

Hospodková, A.; Hájek, F.; Pangrác, J.; Slavická Zíková, M.; Hubáček, T.; Kuldová, K.; Oswald, J.; Vaněka, T.; Vetushka, A.; Čížek, J.; Liedke, M. O.; Butterling, M.; Wagner, A.

This work suggests new alternative explanation why a single InGaN quantum well (QW) or the deepest QWs in the multiple quantum well (MQW) structures suffer with a high non-radiative recombination rate. According to SIMS results, positron annihilation spectroscopy and photoluminescence measurements we suggest that vacancy of Ga in complex with hydrogen atoms can play a dominant role in non-radiative Shockley-Read-Hall recombination of the deepest QWs in InGaN/GaN MQW structures. Vacancy of gallium originate dominantly in GaN buffer layers grown at higher temperatures in H2 atmosphere and are transported to the InGaN/GaN MQW region by diffusion, where they are very effectively trapped in InGaN layers and form complex defects with hydrogen atoms during epitaxy of InGaN layers. Trapping of gallium vacancies is another suggested mechanism explaining why the widely used In containing prelayers help to increase the luminescence efficiency of the InGaN/GaN MQW active region grown above them. Understanding the mechanism why the luminescence efficiency is suppressed in deeper QWs may be very important for LED community and can help to develop new improved technologies for the growth of InGaN/GaN MQW active region.

Keywords: positron annihilation spectroscopy; positron annihilation lifetime spectroscopy; quantum wells; InGaN; hydrogen complexes; GaN; vacancy

Permalink: https://www.hzdr.de/publications/Publ-31257
Publ.-Id: 31257


P1819 - Verfahren zur Herstellung eines keramischen Materials mit lokal einstellbarem Permeabilitätsgradienten, dessen Anwendung in einem Beschichtungsverfahren sowie dessen Verwendung

Bürger, D.; Krüger, S.; Skorupa, I.; Schmidt, H.; Du, N.

Die Erfindung betrifft ein Verfahren zur Herstellung eines keramischen Materials mit lokal einstellbarem Permeabilitätsgradienten, dessen Anwendung in einem Beschichtungsverfahren- Materialbearbeitungsverfahren sowie dessen Verwendung. Die Aufgabe ein Material zur Verfügung zu stellen, welches zum Leiten und Isolieren von Magnetfeldern geeignet ist sowie in magnetischen Kopplungselementen verwendet werden kann, wird durch ein Verfahren zur Herstellung eines keramischen Materials mit lokal einstellbarem Permeabilitätsgradienten gelöst, wobei das Verfahren folgende Schritte umfasst: - Erzeugen eines keramischen Materials mittels Erhitzen einer Ausgangsmaterialkomposition bis zu einer Temperatur unterhalb der Schmelztemperatur der Ausgangsmaterialkomposition, - Abkühlen des erzeugten keramischen Materials auf Raumtemperatur nach einer definierten Abkühlrate zur Einstellung einer Vortex-Dichte in dem erzeugten keramischen Material, und - nachfolgende lokale Temperaturbehandlung zum Erhitzen des keramischen Materials über dessen ferroelektrische Ordnungstemperatur und zum Einstellen des lokalen Permeabilitätsgradienten.

  • Patent
    DE102018125270 - Offenlegung 16.04.2020; Nachanmeldungen: WO

Permalink: https://www.hzdr.de/publications/Publ-31256
Publ.-Id: 31256


Boosting Room-Temperature Magneto-Ionics in a Non-Magnetic Oxide Semiconductor

de Rojas, J.; Quintana, A.; Lopeandía, A.; Salguero, J.; Costa-Krämer, J. L.; Abad, L.; Liedke, M. O.; Butterling, M.; Wagner, A.; Henderick, L.; Dendooven, J.; Detavernier, C.; Sort, J.; Menéndez, E.

Voltage control of magnetism through electric field-induced oxygen motion (magneto-ionics) could represent a significant breakthrough in the pursuit for new strategies to enhance energy efficiency in magnetically actuated devices. Boosting the induced changes in magnetization, magneto-ionic rates and cyclability continue to be key challenges to turn magneto-ionics into real applications. Here, it is demonstrated that room-temperature magneto-ionic effects in electrolyte-gated paramagnetic Co3O4 films can be largely increased both in terms of generated magnetization (6 times larger) and speed (35 times faster) if the electric field is applied using an electrochemical capacitor configuration (utilizing an underlying conducting buffer layer) instead of placing the electric contacts at the side of the semiconductor (electricdouble-layer transistor-like configuration). This is due to a greater uniformity and strength of the electric field in the capacitor design. These results are appealing to widen the use of ion migration in technological applications such as neuromorphic computing or iontronics in general.

Keywords: positron annihilation spectroscopy; Co3O4; Doppler broadening; ionic transport; magnetic switch; defects

Permalink: https://www.hzdr.de/publications/Publ-31255
Publ.-Id: 31255


A New Mechanism for Void-Cascade Interaction from Non-destructive Depth-resolved Atomic-scale Measurements of Ion Irradiation-induced Defects in Fe

Agarwal, S.; Liedke, M. O.; Jones, A. C. L.; Reed, E.; Kohnert, A. A.; Uberuaga, B. P.; Wang, Y. Q.; Cooper, J.; Kaoumi, D.; Li, N.; Auguste, R.; Hosemann, P.; Capolungo, L.; Edwards, D. J.; Butterling, M.; Hirschmann, E.; Wagner, A.; Selim, F. A.

The non-destructive investigation of single vacancies and vacancy clusters in ion irradiated samples requires a depth-resolved probe with atomic sensitivity to defects. The recent development of short-pulsed positron beams provides such a probe. Here, we combine depth-resolved Doppler broadening and positron annihilation lifetime spectroscopies to identify vacancy clusters in ion irradiated Fe and measure their density as a function of depth. Despite large concentrations of dislocations and voids in the pristine samples, positron annihilation measurements uncovered the structure of vacancy-clusters and the change in their size and density with irradiation dose. When combined with TEM measurements, the study demonstrates that the increase in the density of small vacancy clusters with irradiation is associated with a remarkable reduction in the size of large voids, revealing a novel mechanism for the interaction of cascade damage with voids in ion irradiated materials, a consequence of the high porosity of the initial microstructure.

Keywords: positron annihilation spectroscopy; positron annihilation lifetime spectroscopy; Doppler broadening; irradiation; Fe; defects; vacancy clusters; TEM

Permalink: https://www.hzdr.de/publications/Publ-31254
Publ.-Id: 31254


Characterisation of micropores in plasma deposited SiOx films by means of positron annihilation lifetime spectroscopy

Hoppe, C.; Mitschker, F.; Butterling, M.; Liedke, M. O.; de Los Arcos, T.; Awakowicz, P.; Wagner, A.; Grundmeier, G.

The effect of average incorporated ion energy and impinging atomic oxygen flux on the structure and permeability of SiOx thin films by a microwave driven low-pressure discharge with additional RF bias is studied by means of positron annihilation lifetime spectroscopy (PALS) and complementary analytical approaches. The film growth and structure were controlled by the particle fluxes. Acorrelation between the pore sizes and pore size distribution as measured by positron annihilation lifetime spectroscopy (PALS) and the adjusted plasma parameters was established. The corresponding barrier performance was measured by oxygen transmission rate (OTR) and could be explained by the pore size distribution. The dominant pore size characteristic for dangling bonds within the SiOx-network was found to be in the range of 0.8 nm. The chemical composition and morphology were analysed by means of X-ray photoelectron spectroscopy (XPS), FTIR diffuse reflectance measurements (DRIFT) and atomic force microscopy (AFM). It was observed that a combination of both an increase in incorporated energy per deposited Si atom and low oxygen to silicon ratio resulted in an enhanced cross-linking of the SiOx network and thereby lead to a decrease in micropore density and to a shift of the pore size distribution function to lower values.

Keywords: positron annihilation spectroscopy; positron annihilation lifetime spectroscopy; positron; SiOx; Doppler broadening; PALS; FTIR

Permalink: https://www.hzdr.de/publications/Publ-31253
Publ.-Id: 31253


Procedures for the GMP-Compliant Production and Quality Control of [18F]PSMA-1007: A Next Generation Radiofluorinated Tracer for the Detection of Prostate Cancer

Cardinale, J.; Martin, R.; Remde, Y.; Schäfer, M.; Hienzsch, A.; Hübner, S.; Zerges, A.-M.; Marx, H.; Hesse, R.; Weber, K.; Smits, R.; Hoepping, A.; Müller, M.; Neels, O.; Kopka, K.

Radiolabeled tracers targeting the prostate-specific membrane antigen (PSMA) have become important radiopharmaceuticals for the PET-imaging of prostate cancer. In this connection, we recently developed the fluorine-18-labelled PSMA-ligand [18F]PSMA-1007 as the next generation radiofluorinated Glu-ureido PSMA inhibitor after [18F]DCFPyL and [18F]DCFBC. Since radiosynthesis so far has been suffering from rather poor yields, novel procedures for the automated radiosyntheses of [18F]PSMA-1007 have been developed. We herein report on both the two-step and the novel one-step procedures, which have been performed on different commonly-used radiosynthesisers. Using the novel one-step procedure, the [18F]PSMA-1007 was produced in good radiochemical yields ranging from 25 to 80% and synthesis times of less than 55 min. Furthermore, upscaling to product activities up to 50 GBq per batch was successfully conducted. All batches passed quality control according to European Pharmacopoeia standards. Therefore, we were able to disclose a new, simple and, at the same time, high yielding production pathway for the next generation PSMA radioligand [18F]PSMA-1007. Actually, it turned out that the radiosynthesis is as easily realised as the well-known [18F]FDG synthesis and, thus, transferable to all currently-available radiosynthesisers. Using the new procedures, the clinical daily routine can be sustainably supported in-house even in larger hospitals by a single production batch.

Keywords: [18F]PSMA-1007; fluorine-18; PSMA; automation; prostate cancer; PET

Permalink: https://www.hzdr.de/publications/Publ-31252
Publ.-Id: 31252


Carbon ion radiotherapy: impact of tumor differentiation on local control in experimental prostate carcinomas

Glowa, C.; Peschke, P.; Brons, S.; Neels, O.; Kopka, K.; Debus, J.; Karger, C. P.

Background: To summarize the research activities of the “clinical research group heavy ion therapy”, funded by the German Research Foundation (DFG, KFO 214), on the impact of intrinsic tumor characteristics (grading, hypoxia) on local tumor control after carbon (12C-) ion- and photon irradiations. Methods: Three sublines of syngeneic rat prostate tumors (R3327) with various differentiation levels (highly (-H), moderately (-HI) or anaplastic (-AT1), (diameter 10 mm) were irradiated with 1, 2 and 6 fractions of either 12C-ions or 6 MV photons using increasing dose levels. Primary endpoint was local tumor control at 300 days. The relative biological effectiveness (RBE) of 12C-ions was calculated from TCD50-values (dose at 50% tumor control probability) of photons and 12C-ions and correlated with intrinsic tumor parameters. For the HI-subline, larger tumors (diameter 18 mm) were irradiated with either carbon ions, oxygen ions or photons under ambient as well as hypoxic conditions to determine the variability of the RBE under different oxygenation levels. In addition, imaging, histology and molecular analyses were performed to decipher the underlying mechanisms. Results: Experimental results revealed (i) a smaller variation of the TCD50-values between the three tumor sublines for 12C-ions (23.6 - 32.9 Gy) than for photons (38.2 - 75.7 Gy), (ii) steeper dose-response curves for 12C-ions, and (iii) an RBE that increased with tumor grading (1.62 ± 0.11 (H) vs 2.08 ± 0.13 (HI) vs 2.30 ± 0.08 (AT1)). Large HI-tumors resulted in a marked increase of TCD50, which was increased further by 15% under hypoxic relative to oxic conditions. Noninvasive imaging, histology and molecular analyses identified hypoxia as an important radioresistance factor in photon therapy. Conclusions: The dose-response studies revealed a higher efficacy of 12C-ions relative to photon therapy in the investigated syngeneic tumor model. Hypoxia turned out to be at least one important radioresistance factor, which can be partly overridden by high-LET ion beams. This might be used to increase treatment effectiveness also in patients. The results of this project served as a starting point for several ongoing research projects.

Keywords: Carbon ion radiotherapy; relative biological effectiveness (RBE); prostate tumor; hypoxia imaging

Permalink: https://www.hzdr.de/publications/Publ-31250
Publ.-Id: 31250


Diagnostic performance of 68Ga-PSMA-11 (HBED-CC) PET/CT in patients with recurrent prostate cancer: evaluation in 1007 patients

Afshar-Oromieh, A.; Holland-Letz, T.; Giesel, F. L.; Kratochwil, C.; Mier, W.; Haufe, S.; Debus, N.; Eder, M.; Eisenhut, M.; Schäfer, M.; Neels, O.; Hohenfellner, M.; Kopka, K.; Kauczor, H.-U.; Debus, J.; Haberkorn, U.

Purpose Since the clinical introduction of 68Ga-PSMA-11 PET/CT, this imaging method has rapidly spread and is now regarded as a significant step forward in the diagnosis of recurrent prostate cancer (PCa). The aim of this study was to analyse the influence of several variables with possible influence on PSMA ligand uptake in a large cohort. Methods We performed a retrospective analysis of 1007 consecutive patients who were scanned with 68Ga-PSMA-11 PET/CT (1 h after injection) from January 2014 to January 2017 to detect recurrent disease. Patients with untreated primary PCa or patients referred for PSMA radioligand therapy were excluded. The possible effects of different variables including PSA level and PSA doubling time (PSADT), PSA velocity (PSAVel), Gleason score (GSC, including separate analysis of GSC 7a and 7b), ongoing androgen deprivation therapy (ADT), patient age and amount of injected activity were evaluated. Results In 79.5% of patients at least one lesion with characteristics suggestive of recurrent PCa was detected. A pathological (positive) PET/CT scan was associated with PSA level and ADT. GSC, amount of injected activity, patient age, PSADT and PSAVel were not associated with a positive PET/CT scan in multivariate analysis. Conclusion 68Ga-PSMA-11 PET/CT detects tumour lesions in a high percentage of patients with recurrent PCa. Tumour detection is clearly associated with PSA level and ADT. Only a tendency for an association without statistical significance was found between higher GSC and a higher probability of a pathological PET/CT scan. No associations were found between a pathological 68Ga-PSMA-11 PET/CT scan and patient age, amount of injected activity, PSADT or PSAVel.

Keywords: Prostate cancer; PET/CT; positron emission tomography; PSMA; prostate-specific membrane antigen

Permalink: https://www.hzdr.de/publications/Publ-31249
Publ.-Id: 31249


Tracer uptake in mediastinal and paraaortal thoracic lymph nodes as a potential pitfall in image interpretation of PSMA ligand PET/CT

Afshar-Oromieh, A.; Sattler, L. P.; Steiger, K.; Holland-Letz, T.; Livorsi Da Cunha, M.; Mier, W.; Neels, O.; Kopka, K.; Weichert, W.; Haberkorn, U.

Purpose Since the introduction of 68Ga-PSMA-11 PET/CT for imaging prostate cancer (PC) we have frequently observed mediastinal lymph nodes (LN) showing tracer uptake despite being classified as benign. The aim of this evaluation was to further analyze such LN. Methods Two patient groups with biphasic 68Ga-PSMA-11 PET/CT at 1 h and 3 h p.i. were included in this retrospective evaluation. Group A (n = 38) included patients without LN metastases, and group B (n = 43) patients with LN metastases of PC. SUV of mediastinal/paraaortal LN of group A (n = 100) were compared to SUV of LN metastases of group B (n = 91). Additionally, 22 randomly selected mediastinal and paraaortal LN of patients without PC were immunohistochemically (IHC) analyzed for PSMA expression. Results In group A, 7/38 patients (18.4%) presented with at least one PSMA-positive mediastinal LN at 1 h p.i. and 3/38 (7.9%) positive LN at 3 h p.i. with a SUVmax of 2.3 ± 0.7 at 1 h p.i. (2.0 ± 0.7 at 3 h p.i.). A total of 11 PSMA-positive mediastinal/paraaortal LN were detected in nine patients considering both imaging timing points. SUVmax of LN-metastases was 12.5 ± 13.2 at 1 h p.i. (15.8±17.0 at 3 h p.i.). SUVmax increased clearly (> 10%) between 1 h and 3 h p.i. in 76.9% of the LN metastases, and decreased significantly in 72.7% of the mediastinal/paraaortal LN. By IHC, PSMA-expression was observed in intranodal vascular endothelia of all investigated LN groups and to differing degrees within germinal centers of 15/22 of them (68.1%). Expression was stronger in mediastinal nodes (p = 0.038) and when follicular hyperplasia was present (p = 0.050). Conclusion PSMA-positive mediastinal/paraaortal benign LN were visible in a notable proportion of patients. PSMA-positivity on the histopathological level was associated with the activation state of the LN. However, in contrast to LN metastases of PC, they presented with significantly lower uptake, which, in addition, usually decreased over time.

Keywords: Prostate cancer; PET/CT; Mediastinal; Mediastinal/paraaortal; Lymph nodes; PSMA; Prostate-specific membrane antigen; 68Ga-PSMA-11

Permalink: https://www.hzdr.de/publications/Publ-31248
Publ.-Id: 31248


Vacancy-Hydrogen Interaction in Niobium during Low-Temperature Baking

Wenskat, M.; Čižek, J.; Liedke, M. O.; Butterling, M.; Bate, C.; Haušild, P.; Hirschmann, E.; Wagner, A.; Weise, H.

A recently discovered modified low-temperature baking leads to reduced surface losses and an increase of the accelerating gradient of superconducting TESLA shape cavities. We will show that the dynamics of vacancy-hydrogen complexes at low-temperature baking lead to a suppression of lossy nanohydrides at 2 K and thus a significant enhancement of accelerator performance. Utilizing Doppler broadening Positron Annihilation Spectroscopy, Positron Annihilation Lifetime Spectroscopy and instrumented nanoindentation, samples made from European XFEL niobium sheets were investigated. We studied the evolution of vacancies in bulk samples and in the sub-surface region and their interaction with hydrogen at different temperature levels during in-situ and ex-situ annealing.

Keywords: positron annihilation spectroscopy; PALS; Doppler broadening; Nb RF cavities; superconductivity

Permalink: https://www.hzdr.de/publications/Publ-31247
Publ.-Id: 31247


Quenched-in Vacancies and Hardening of Fe–Al Intermetallics

Prochazka, I.; Vlasak, T.; Cizek, J.; Lukac, F.; Liedke, M. O.; Anwand, W.; Jiraskova, Y.; Janickovice, D.

The role of vacancies in hardening of Fe–Al intermetallic alloys were studied in the present work for a wide range of Al concentrations from 20 to 50 at%. The alloys quenched from 1000 ◦C as well as those annealed subsequently at 520 ◦C for 1 h were subject to study. Slow-positron beam experiments combined with Vicker’s microhardness tests were utilised. Hardness of Fe–Al alloys exhibited a somewhat complex dependence on Al content which could not be fully explained purely by consideration of intermetallic phases formed. This happens due to additional hardening effect caused by quenched-in vacancies. The concentrations of vacancies were estimated from positron back-diffusion data and found to rise for Al content above 25 at%. Correlation of vacancy concentrations with hardness data for the quenched and annealed alloys has revealed that hardening of alloys with a low Al content (< 30 at%) is originated predominantly by anti-phase boundaries while hardening induced by quenched-in vacancies dominates for alloys with a higher Al content (30–50 at%).

Keywords: positron annihilation spectroscopy; Doppler broadening; FeAl; defetcs; SPONSOR

Permalink: https://www.hzdr.de/publications/Publ-31246
Publ.-Id: 31246


Investigation of Optical Properties and Defects Structure of Rare Earth (Sm, Gd, Ho) Doped Zinc Oxide Thin Films Prepared by Pulsed Laser Deposition

Novotny, M.; Hruska, P.; Fitl, P.; Maresova, E.; Havlova, S.; Bulir, J.; Fekete, L.; Yatskiv, R.; Vrnata, M.; Cizek, J.; Liedke, M. O.; Lancok, J.

Rare earths (RE = Sm, Gd, Ho) doped ZnO thin films were grown by pulsed laser deposition in oxygen ambient at pressure of 10 Pa on fused silica and Si(100) substrates at room temperature. A good optical quality of the films was confirmed by transmittance measurement in the visible spectral region. Photoluminescence suggested RE3+ oxidation state as confirmed at ZnO:Sm, where local structure was inhomogeneous. ZnO:Sm film exhibited the highest electrical resistivity while ZnO:Ho the lowest. Nanocrystalline structure of the films was observed by atomic force microscopy and X-ray diffraction. Defects structure was examined by variable energy positron annihilation spectroscopy. All ZnO:RE films exhibited significantly higher values of the S parameter as well as shorter positron diffusion lengths compared to ZnO monocrystal reference due to trapping of positrons at open volumes associated with grain boundaries. We observed the impact of the type of RE dopant on optical and electrotransport properties while the defect structure remained unchanged.

Keywords: Doped Zinc Oxide; Sm; positron annihilation spectroscopy; ZnO; Gd; Ho; defects

Permalink: https://www.hzdr.de/publications/Publ-31245
Publ.-Id: 31245


Tailored fabrication of iridium nanoparticle-sensitized titanium oxynitride nanotubes for solar-driven water splitting: Experimental insights on the photocatalytic-activity-defects relationship

Eid, K.; Soliman, K. A.; Abdulmalik, D.; Mitoraj, D.; Sleim, M. H.; Liedke, M. O.; El-Sayed, H. A.; Aljaber, A. S.; Al-Qaradawi, I. Y.; Mendoza Reyes, O.; Abdullah, A. M.

Understanding the photocatalytic–activity–defects relationship of titanium oxynitride nanotubes (TiON-NTs) is important for tailoring their photocatalytic performance. Herein, we fabricated highly ordered and vertically aligned nanotube arrays of TiON-NT-functionalized with iridium nanoparticles denoted as (Ir/TiON-NTs) for solar-driven water splitting. Positron annihilation lifetime spectroscopy (PALS) and variable-energy positron annihilation spectroscopy (VEPAS) were performed to quantify the vacancy-type defects of Ir/TiON-NTs relative to TiON-NTs and TiO2-NTs. The results display that the Ir/TiON-NTs exhibit abundant defects such as small nitrogen vacancies, larger size vacancy clusters, and small voids. The obtained photocurrent density of the Ir/TiON-NTs (11.3 mA cm−2) is about 3.97, 5, and 11.89 times higher than that of Ir/TiO2-NTs, TiON-NTs, and TiO2-NTs, respectively. The Mott–Schottky analysis revealed the highest significant negative shift in the band potential and the lowest donor density of Ir/TiON-NTs compared to its counterparts. This result is attributed to the unique structural and compositional merits of Ir/TiON-NTs despite the abundant defects, which delay the charge recombination and improve the photocatalytic activity. The presented study may open new frontiers on engineering the defects of metal oxynitrides with metal-based catalysts for photocatalytic applications.

Keywords: titanium oxynitride; PALS; positron annihilation spectroscopy; nanotubes; iridium nanoparticles

Permalink: https://www.hzdr.de/publications/Publ-31244
Publ.-Id: 31244


F-18 labelled PSMA-1007: biodistribution, radiation dosimetry and histopathological validation of tumor lesions in prostate cancer patients

Giesel, F. L.; Hadaschik, B.; Cardinale, J.; Radtke, J.; Vinsensia, M.; Lehnert, W.; Kesch, C.; Tolstov, Y.; Singer, S.; Grabe, N.; Duensing, S.; Schäfer, M.; Neels, O.; Mier, W.; Haberkorn, U.; Kopka, K.; Kratochwil, C.

Purpose The prostate-specific membrane antigen (PSMA) targeted positron-emitting-tomography (PET) tracer 68Ga-PSMA-11 shows great promise in the detection of prostate cancer. However, 68Ga has several shortcomings as a radiolabel including short half-life and non-ideal energies, and this has motivated consideration of 18F-labelled analogs. 18F-PSMA-1007 was selected among several 18F-PSMA-ligand candidate compounds because it demonstrated high labelling yields, outstanding tumor uptake and fast, non-urinary background clearance. Here, we describe the properties of 18F-PSMA-1007 in human volunteers and patients. Methods Radiation dosimetry of 18F-PSMA-1007 was determined in three healthy volunteers who underwent whole-body PET-scans and concomitant blood and urine sampling. Following this, ten patients with high-risk prostate cancer underwent 18F-PSMA-1007 PET/CT (1 h and 3 h p.i.) and normal organ biodistribution and tumor uptakes were examined. Eight patients underwent prostatectomy with extended pelvic lymphadenectomy. Uptake in intra-prostatic lesions and lymph node metastases were correlated with final histopathology, including PSMA immunostaining. Results With an effective dose of approximately 4.4–5.5 mSv per 200–250 MBq examination, 18F-PSMA-1007 behaves similar to other PSMA-PET agents as well as to other 18F-labelled PET-tracers. In comparison to other PSMA-targeting PET-tracers, 18F-PSMA-1007 has reduced urinary clearance enabling excellent assessment of the prostate. Similar to 18F-DCFPyL and with slightly slower clearance kinetics than PSMA-11, favorable tumor-to-background ratios are observed 2–3 h after injection. In eight patients, diagnostic findings were successfully validated by histopathology. 18F-PSMA-1007 PET/CT detected 18 of 19 lymph node metastases in the pelvis, including nodes as small as 1 mm in diameter. Conclusion 18F-PSMA-1007 performs at least comparably to 68Ga-PSMA-11, but its longer half-life combined with its superior energy characteristics and non-urinary excretion overcomes some practical limitations of 68Ga-labelled PSMA-targeted tracers.

Keywords: 18F-PSMA; F-18-PSMA; PSMA-1007; PET/CT; Positron emission tomography

Permalink: https://www.hzdr.de/publications/Publ-31242
Publ.-Id: 31242


Small Crown-Ether Complexes as Molecular Models for Dihydrogen Adsorption in Undercoordinated Extraframework Cations in Zeolites

Wulf, T.; Heine, T.

1:1 metal complexes of small crown ethers are structurally similar to extraframework sites in metal-exchanged zeolites. Using ab initio calculations, we show that adsorbed molecular hydrogen follows the same trends in adsorption energies and vibrational frequencies at both types of metal sites. Unlike zeolites, crown ethers can be characterized in the gas phase, which opens new possibilities for understanding the bonding of dihydrogen at undercoordinated metal sites to help guide the rational design of porous materials for hydrogen isotope separation. Because more strongly binding adsorbates affect the geometry of the hosts, the similarity of crown ethers and zeolites with regard to the vibrational spectra of the adsorbed molecule seems to be limited to H₂.

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Publ.-Id: 31241


18F-Labelled PSMA-1007 shows similarity in structure, biodistribution and tumour uptake to the theragnostic compound PSMA-617

Giesel, F. L.; Cardinale, J.; Schäfer, M.; Neels, O.; Benesova, M.; Mier, W.; Haberkorn, U.; Kopka, K.; Kratochwil, C.

Without Abstract

Permalink: https://www.hzdr.de/publications/Publ-31240
Publ.-Id: 31240


Radiosynthesis of a Novel PET Fluoronicotinamide for Melanoma Tumour PET Imaging; [18F]MEL050

Greguric, I.; Taylor, S.; Pham, T.; Wyatt, N.; Jiang, C. D.; Bourdier, T.; Loch, C.; Roselt, P.; Neels, O.; Katsifis, A.

[18F]6-Fluoro-N-[2-(diethylamino)ethyl]nicotinamide [18F]MEL050 is a novel nicotinamide-based radiotracer, designed to target random metastatic dissemination of melanoma tumours by targeting melanin. Preclinical studies suggest that [18F]MEL050 has an excellent potential to improve diagnosis and staging of melanoma. Here we report the radiochemical optimization conditions of [18F]MEL050 and its large scale automated synthesis using a GE FXFN automated radiosynthesis module for clinical, phase-1 investigation. [18F]MEL050 was prepared via a one-step synthesis using no-carrier added K[18F]F-Kryptofix® 222 (DMSO, 170° C, 5 min) followed by HPLC purification. Using 6-chloro-N-[2-(diethylamino)ethyl]nicotinamide as precursor, [18F]MEL050 was obtained in 40-46% radiochemical yield (non-decay corrected), in greater than 99.9% radiochemical purity and specific activity ranging from 240 to 325 GBq µmol(-1). Total synthesis time including formulation was 40 min and [18F]MEL050 was stable (99.8%) in PBS for 6 h.

Permalink: https://www.hzdr.de/publications/Publ-31239
Publ.-Id: 31239


Convection Caused Symmetry Breaking of Azimuthal Magnetorotational Instability in a Liquid Metal Taylor Couette Flow

Seilmayer, M.; Ogbonna, J. E.; Stefani, F.

This are the experimental and numerical results for the publication "Convection Caused Symmetry Breaking of Azimuthal Magnetorotational Instability in a Liquid Metal Taylor Couette Flow ". It contains pictures, experimental results, tex files, COMSOL simulation file and PDF.

Keywords: MRI, magnetohydrodynamic, thermal convection, Taylor Couette

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  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-06-25
    DOI: 10.14278/rodare.380
    License: CC-BY-4.0

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Permalink: https://www.hzdr.de/publications/Publ-31238
Publ.-Id: 31238


Biochemical recurrence of prostate cancer: initial results with 18F-PSMA-1007 PET/CT

Giesel, F. L.; Will, L.; Kesch, C.; Freitag, M.; Kremer, C.; Merkle, J.; Neels, O.; Cardinale, J.; Hadaschik, B.; Hohenfellner, M.; Kopka, K.; Haberkorn, U.; Kratochwil, C.

Biochemical recurrence (BCR) is a concern for prostate cancer patients after local treatment. 68Ga-labeled prostate-specific membrane antigen (PSMA) ligands have significantly improved prostate cancer imaging. However, several 18F-labeled ligands that were developed as fluorinated tracers might present advantages. In this study, we analyzed the potential of 18F-PSMA-1007 in patients with BCR. Methods: Twelve patients with BCR after local treatment underwent PET/CT scans 1 and 3 h after injection of 18F-PSMA-1007. Results: 18F-PSMA-1007 PET/CT detected lesions in 9 of 12 patients (75%). A significant difference was observed when comparing the tracer uptake in 18F-PSMA-1007–positive lesions 1 and 3 h after injection (median SUVmax, 7.00 vs. 11.34; P < 0.001; n = 76). Fortyfour (88%) of 50 18F-PSMA-1007–positive lymph nodes had a shortaxis diameter of less than 8 mm. Conclusion: In this pilot study, 18F-PSMA-1007 PET/CT presented high potential for localization of recurrent disease in prostate cancer patients with BCR.

Keywords: peptides; PET/CT; biochemical recurrence; 18F-PSMA-1007; PSMA-PET; prostate cancer

Permalink: https://www.hzdr.de/publications/Publ-31237
Publ.-Id: 31237


Intra-individual comparison of 18F-PSMA-1007 and 18F-DCFPyL PET/CT in the prospective evaluation of patients with newly diagnosed prostate carcinoma: A pilot study

Giesel, F. L.; Will, L.; Lawal, I.; Lengana, T.; Kratochwil, C.; Vorster, M.; Neels, O.; Reyneke, F.; Haberkorn, U.; Kopka, K.; Sathekge, M.

The introduction of 18F-labeled prostate-specific membrane antigen (PSMA)–targeted PET/CT tracers, first 18F-DCFPyL (2-(3-{1-carboxy-5-[(6-18F-fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid) andmore recently 18F-PSMA-1007 (((3S,10S,14S)-1-(4-(((S)-4-carboxy-2-((S)-4-carboxy-2-(6-18F-fluoronicotinamido)butanamido)butanamido)methyl)phenyl)-3-(naphthalen-2-ylmethyl)-1,4,12-trioxo-2,5,11,13-tetraazahexadecane-10,14,16-tricarboxylic acid)), have demonstrated promising results for the diagnostic workup of prostate cancer. This clinical study presents an intraindividual comparison to evaluate tracer-specific characteristics of 18F-DCFPyL versus 18F-PSMA-1007. Methods: Twelve prostate cancer patients, drug-na¨ıve or before surgery, received similar activities of about 250 MBq of 18F-DCFPyL and 18F-PSMA-1007 48 h apart and were imaged 2 h after injection on the same PET/CT scanner using the same reconstruction algorithm. Normal-organ biodistribution and tumor uptake were quantified using SUVmax. Results: PSMA-positive lesions were detected in 12 of 12 prostate cancer patients. Both tracers, 18F-DCFPyL and 18F-PSMA-1007, detected the same lesions. No statistical significance could be observed when comparing the SUVmax of 18F-DCFPyL and 18F-PSMA-1007 for local tumor, lymph node metastases, and bone metastases. With regard to normal organs, 18F-DCFPyL had statistically significant higher uptake in kidneys, urinary bladder, and lacrimal gland. Vice versa, significantly higher uptake of 18F-PSMA-1007 in muscle, submandibular and sublingual gland, spleen, pancreas, liver, and gallbladder was observed. Conclusion: Excellent imaging quality was achieved with both 18F-DCFPyL and 18F-PSMA-1007, resulting in identical clinical findings for the evaluated routine situations. Nonurinary excretion of 18F-PSMA-1007 might present some advantage with regard to delineation of local recurrence or pelvic lymph node metastasis in selected patients; the lower hepatic background might favor 18F-DCFPyL in late stages, when rare cases of liver metastases can occur.

Keywords: 18F-PSMA-1007; 18F-DCFPyL; prostate carcinoma; PET/CT; PSMA

Permalink: https://www.hzdr.de/publications/Publ-31236
Publ.-Id: 31236


Intra-individual comparison of 18F-PSMA-1007-PET/CT, multi-parametric MRI and radical prostatectomy specimen in patients with primary prostate cancer - a retrospective, proof of concept study

Kesch, C.; Vinsensia, M.; Radtke, J. P.; Schlemmer, H. P.; Heller, M.; Ellert, E.; Holland-Letz, T.; Duensing, S.; Grabe, N.; Afshar-Oromieh, A.; Wieczorek, K.; Schäfer, M.; Neels, O.; Cardinale, J.; Kratochwil, C.; Hohenfellner, M.; Kopka, K.; Haberkorn, U.; Hadaschik, B.; Giesel, F. L.

68Ga-prostate-specific membrane antigen (PSMA)-11 PET/CT represents an advanced method for the staging of primary prostate cancer (PCa) and diagnosis of recurrent or metastatic PCa. However, because of the narrow availability of 68Ga the development of alternative tracers is of high interest. The objective of this study was to examine the value of the new PET tracer 18F-PSMA-1007 for the staging of local disease by comparing it with multiparametric MRI (mpMRI) and radical prostatectomy (RP) histopathology. Methods: In 2016, 18F-PSMA-1007 PET/CT was performed in 10 men with biopsy-confirmed high-risk PCa. Nine patients underwent mpMRI in the process of primary diagnosis. Consecutively, RP was performed in all 10 men. Agreement analysis was performed retrospectively. PSMA staining was added for representative sections in RP specimen slices. Localization and agreement analysis of 18F-PSMA-1007 PET/CT, mpMRI, and RP specimens was performed by dividing the prostate into 38 sections as described in the prostate imaging reporting and data system (PI-RADS) (version 2). Sensitivity, specificity, positive predictive values, negative predictive values (NPVs), and accuracy were calculated for total and near-total agreement. Results: 18F-PSMA-1007 PET/CT had an NPV of 68% and an accuracy of 75%, and mpMRI had an NPV of 88% and an accuracy of 73% for total agreement. Near-total agreement analysis resulted in an NPV of 91% and an accuracy of 93% for 18F-PSMA-1007 PET/CT and 91% and 87% for mpMRI, respectively. Retrospective combination of mpMRI and PET/CT had an accuracy of 81% for total and 93% for near-total agreement. Conclusion: Comparison with RP histopathology demonstrates that 18F-PSMA-1007 PET/CT is promising for accurate local staging of PCa.

Keywords: 18F-PSMA; PSMA-1007; prostate cancer; PET/CT; mpMRI

Permalink: https://www.hzdr.de/publications/Publ-31235
Publ.-Id: 31235


Preclinical Evaluation of 18F-PSMA-1007: A New PSMA-Ligand for Prostate Cancer Imaging

Cardinale, J.; Schäfer, M.; Benesova, M.; Bauder-Wüst, U.; Leotta, K.; Eder, M.; Neels, O.; Haberkorn, U.; Giesel, F. L.; Kopka, K.

In recent years, several radiotracers targeting the prostate-specific membrane antigen (PSMA) have been introduced. Some of them have had a high clinical impact on the treatment of patients with prostate cancer. However, the number of 18F-labeled tracers addressing PSMA is still limited. Therefore, we aimed to develop a radiofluorinated molecule resembling the structure of therapeutic PSMA-617. Methods: The nonradioactive reference compound PSMA-1007 and the precursor were produced by solid-phase chemistry. The radioligand 18F-PSMA-1007 was produced by a 2-step procedure with the prosthetic group 6-18F-fluoronicotinic acid 2,3,5,6-tetrafluorophenyl ester. The binding affinity of the ligand for PSMA and its internalization properties were evaluated in vitro with PSMA-positive LNCaP (lymph node carcinoma of the prostate) cells. Further, organ distribution studies were performed with mice bearing LNCaP and PC-3 (prostate cancer cell line; PSMA-negative) tumors. Finally, small-animal PET imaging of an LNCaP tumor–bearing mouse was performed. Results: The identified ligand had a binding affinity of 6.7 ± 1.7 nM for PSMA and an exceptionally high internalization ratio (67% ± 13%) in vitro. In organ distribution studies, high and specific tumor uptake (8.0 ± 2.4 percentage injected dose per gram) in LNCaP tumor–bearing mice was observed. In the small-animal PET experiments, LNCaP tumors were clearly visualized. Conclusion: The radiofluorinated PSMA ligand showed promising characteristics in its preclinical evaluation, and the feasibility of prostate cancer imaging was demonstrated by small-animal PET studies. Therefore, we recommend clinical transfer of the radioligand 18F-PSMA-1007 for use as a diagnostic PET tracer in prestaging and monitoring of prostate cancer.

Keywords: PSMA; 18F; prostate cancer; PET

Permalink: https://www.hzdr.de/publications/Publ-31234
Publ.-Id: 31234


The Theranostic PSMA Ligand PSMA-617 in the Diagnosis of Prostate Cancer by PET/CT: Biodistribution in Humans, Radiation Dosimetry, and First Evaluation of Tumor Lesions

Afshar-Oromieh, A.; Hetzheim, H.; Kratochwil, C.; Benesova, M.; Eder, M.; Neels, O.; Eisenhut, M.; Kübler, W.; Holland-Letz, T.; Giesel, F. L.; Mier, W.; Kopka, K.; Haberkorn, U.

PET imaging with the prostate-specific membrane antigen (PSMA)–targeted radioligand 68Ga-PSMA-11 is regarded as a significant step forward in the diagnosis of prostate cancer (PCa). More recently, a PSMA ligand was developed that can be labeled with 68Ga, 111In, 177Lu, and 90Y. This ligand, named PSMA-617, therefore enables both diagnosis and therapy of PCa. The aims of this evaluation were to clinically investigate the distribution of 68Ga-PSMA-617 in normal tissues and in PCa lesions as well as to evaluate the radiation exposure by the radioligand in PET imaging. Methods: Nineteen patients, most of them with recurrent PCa, were referred for 68Ga-PSMA-617 PET/CT. The quantitative assessment of tracer uptake of several organs and of 53 representative tumor lesions was performed in 15 patients at 1 and 3 h after injection. In 4 additional patients, the same procedure was conducted at 5 min, 1 h, 2 h, 3 h, 4 h, and 5 h after injection. On the basis of the data for these 4 patients (mean injected dose, 231 MBq), the radiation exposure of a 68Ga-PSMA-617 PET/CT was identified. Results: Intense tracer uptake was observed in the kidneys and salivary glands. In 14 of 19 patients (73.7%), at least 1 lesion suspected of being a tumor was detected at 3 h after injection. Of 53 representative tumor lesions selected at 3 h after injection, 47 lesions were visible at 1 h after injection. The mean tumor-to-background ratio for maximum standardized uptake value was 20.4 ± 17.3 (range, 2.3–84.0) at 1 h after injection and 38.2 ± 38.6 (range, 3.6–154.3) at 3 h after injection. The average radiation exposure (effective dose) was approximately 0.021 mSv/MBq. Conclusion: Within healthy organs, the kidneys and salivary glands showed the highest 68Ga-PSMA-617 uptake. The radiation exposure was relatively low. 68Ga-PSMA-617 shows PCa lesions with high contrast. Images obtained between 2 and 3 h after injection seem to be the best option with regard to radiotracer uptake and tumor contrast. Later images can help to clarify unclear lesions.

Keywords: prostate cancer; PET/CT; positron emission tomography; PSMA; prostate-specific membrane antigen; dosimetry

Permalink: https://www.hzdr.de/publications/Publ-31233
Publ.-Id: 31233


Investigation of Epothilone B-Induced Cell Death Mechanisms in Human Epithelial Cancer Cells –in Consideration of Combined Treatment With Ionizing Radiation

Baumgart, T.; Kriesen, S.; Neels, O.; Hildebrandt, G.; Manda, K.

Epothilone B was shown to have promising chemo- and radiosensitizing effects on cells, but the mechanisms underlying cell death remain ambiguous. The aim of the study was to examine selected cell death pathways on the basis of FaDu and A549 cells. Western blot analyses were used for investigation of specific apoptotic markers. Immunofluorescence imaging and flow cytometry were utilized for examination of cell death mechanisms. DNA-staining was used for studying influence of epothilone B on micronucleus rate. We showed that epothilone B can initiate cell death via apoptosis and mitotic catastrophe, but induction of cell death was cell type specific.

Keywords: Apoptosis; Epothilone B; Irradiation; Micronucleus; Mitotic catastrophe

Permalink: https://www.hzdr.de/publications/Publ-31230
Publ.-Id: 31230


ExploreASL/ExploreASL: First stable release

Mutsaerts, H.; Petr, J.; Stritt, M.; Vandemaele, P.; Groot, P.

ExploreASL v1.0.0

  • Software in external data repository
    Publication year 2020
    Programming language: Matlab
    System requirements: Windows/Linux/OS X
    License: Other (Open)
    Hosted on https://github.com/ExploreASL/ExploreASL/tree/v1.0.0:
    DOI: 10.5281/zenodo.3905263

Permalink: https://www.hzdr.de/publications/Publ-31229
Publ.-Id: 31229


Life on a Mesoarchean marine shelf – insights from the world’s oldest known granular iron formation

Smith, A. J. B.; Beukes, N. J.; Gutzmer, J.; Johnson, C. M.; Czaja, A. D.; Nhleko, N.; de Beer, F.; Hoffman, J. W.; Awramik, S. M.

The Nconga Formation of the Mesoarchean (~2.96-2.84 Ga) Mozaan Group of the Pongola Supergroup of southern Africa contains the world’s oldest known granular iron formation. Three dimensional reconstructions of the granules using micro-focus X-ray computed tomography reveal that these granules are microstromatolites coated by magnetite and calcite, and can therefore be classified as oncoids. The reconstructions also show damage to the granule coatings caused by sedimentary transport during formation of the granules and eventual deposition as density currents. The detailed, three dimensional morphology of the granules in conjunction with previously published geochemical and isotope data indicate a biogenic origin for iron precipitation around chert granules on the shallow shelf of one of the oldest supracratonic environments on Earth almost three billion years ago. It broadens our understanding of biologically-mediated iron precipitation during the Archean by illustrating that it took place on the shallow marine shelf coevally with deeper water, below-wave base iron precipitation in micritic iron formations.

Permalink: https://www.hzdr.de/publications/Publ-31228
Publ.-Id: 31228


P1818 - Verfahren zur gezielten Auswahl eines Sensors zur sensorbasierten Sortierung eines Materialgemisches durch Simulation der sensorbasierten Sortierung des Materialgemisches

Kern, M.; Tusa, L.; Gutzmer, J.; van den Boogaart, K. G.

Es wird Verfahren zur Auswahl eines Sensors (1) aus einer Mehrzahl von Sensoren zur sensorbasierten Sortierung eines Materialgemischs (10) anhand einer Materialeigenschaft zur Konzentration eines Wertstoffes vorgeschlagen, wobei in einem ersten Schritt aus dem Materialgemisch (10) repräsentative Einzelproben gewonnen werden (20), in einem zweiten Schritt Materialeigenschaften der Einzelproben gemessen werden (30), in einem dritten Schritt auf Grundlage der gemessenen Materialeigenschaften eine Mehrzahl von simulierten Sortierungen anhand jeweils unterschiedlicher Materialeigenschaften simuliert wird (40), in einem vierten Schritt eine simulierte Sortierung mit einer hohen Wertstoffkonzentration aus der Mehrzahl von simulierten Sortierungen ausgewählt wird, in einem fünften Schritt ein Sensor (1) zur Messung der Materialeigenschaft ausgewählt wird (50), welcher geeignet ist, mindestens eine der Materialeigenschaften, welche für die ausgewählte simulierte Sortierung genutzt wurde, zu messen.

  • Patent
    DE102018217548 - Offenlegung 16.04.2020; Nachanmeldungen: WO

Permalink: https://www.hzdr.de/publications/Publ-31227
Publ.-Id: 31227


P1816 - Reaktor und Verfahren zur kontinuierlichen Gewinnung amphiphiler Siderophore aus einer Mikroorganismenkultur

Schrader, S.; Kutschke, S.; Pollmann, K.; Rudolph, M.

Die Erfindung betrifft einen Reaktor, ein Verfahren und die Verwendung dieses Reaktors in dem Verfahren zur Gewinnung amphiphiler Siderophore aus einer Mikroorganismenkultur. Der Reaktor umfasst die Bauteile: (a) Vorrichtung (40) zum Rühren und/oder Begasen, und (b) Ablauf (70) für Schaum, enthaltend die amphiphilen Siderophore, in der Seitenwand des Reaktors, (c) Deckel (90) wobei die Unterkante des Ablaufs (70) für Schaum als Überlauf in einer Höhe liegt, die im Bereich von 40-75% der Gesamthöhe des Reaktors (10), von unten gemessen, liegt, und wobei der Ablauf (70) für Schaum horizontal nach außen oder schräg nach unten außen verläuft oder als Überlauf ausgestaltet ist.

  • Patent
    DE102018122029 - Offenlegung 12.03.2020; Nachanmeldungen: WO

Permalink: https://www.hzdr.de/publications/Publ-31226
Publ.-Id: 31226


P1814 - Kühlvorrichtung sowie Kühlverfahren basierend auf magnetoelektrischer Kopplung

Hornung, J.; Gottschall, T.

Verschiedene Ausführungsformen betreffen ein Verfahren (700) zum Betreiben einer Kühlvorrichtung (300), das Verfahren (700) aufweisend: ein erstes Verändern eines elektrischen Feldes (304) in einem Feldbereich (306), wobei in dem Feldbereich (306) mindestens ein Magnetsystem mit magnetoelektrischer Kopplung angeordnet ist, und dadurch Erwärmen des mindestens einen Magnetsystems; und, anschließend, ein zweites Verändern des elektrischen Feldes (304) in dem Feldbereich (306) und dadurch Abkühlen des mindestens einen Magnetsystems.

  • Patent
    DE102018118813 - Erteilung 21.11.2019

Permalink: https://www.hzdr.de/publications/Publ-31225
Publ.-Id: 31225


P1813 - Schichtabfolge zur Erzeugung von Elektrolumineszenz und deren Verwendung

Bogusz, A.; Rayapati, V. R.; Skorupa, I.; Schmidt, H.; Bürger, D.; Krüger, S.; Rebohle, L.

Die Erfindung betrifft eine Schichtabfolge zur Erzeugung von Elektrolumineszenz und deren Verwendung, beispielsweise in einem Pixelarray oder in textilen Materialien. Die Aufgabe eine Schichtstruktur anzugeben, die einfach realisierbar bzw. herstellbar sowie einfach aufgebaut ist, mit der Elektrolumineszenz einfach erzeugt werden kann und langzeitstabil einsetzbar ist, wird durch eine Schichtabfolge zur Erzeugung von Elektrolumineszenz gelöst, die mindestens eine polykristalline Seltene-Erd-Manganat-Schicht sowie einen ersten Kontakt, der auf einer Seite der Seltene-Erd-Manganat-Schicht angeordnet ist sowie einen zweiten Kontakt, der auf der gegenüberliegenden Seite des ersten Kontaktes oder auf der gleichen Seite wie der erste Kontakt angeordnet ist, aufweist, wobei in der Seltene-Erd-Manganat-Schicht zwischen dem ersten Kontakt und dem zweiten Kontakt ein Widerstand größer als 100 Ohm ausgebildet ist und wobei die Seltene-Erd-Manganat-Schicht geeignet ist, bei Anlegen einer elektrischen Gleichspannung, lokal im Bereich des sich zwischen den beiden elektrisch leitenden Kontakten ausbildenden elektrischen Feldes in der Seltene-Erd-Manganat-Schicht eine Elektrolumineszenz aufgrund von Stoßionisation auszubilden.

  • Patent
    DE102018117210 - Offenlegung 20.02.2020

Permalink: https://www.hzdr.de/publications/Publ-31224
Publ.-Id: 31224


P1812 - Fluidik-Detektionssystem

Illing, R.; Makarov, D.

Die Erfindung betrifft ein Fluidik-Detektionssystem zur magnetisch-elektrischen Messung einer fluiden Probe, wobei das System jeweils mindestens ein Probenmodul, einen Magnetfeldsensor und einen Magneten umfasst, welche voneinander beabstandet angeordnet sind. Dabei weist das Probenmodul mindestens einen Kanal auf, der zum Befördern einer fluiden Probe entlang einer Fließrichtung ausgebildet ist. Der Magnet erzeugt ein Magnetfeld in einem Mess- und Anregungsbereich des Kanals. Dabei entspricht der Detektionsbereich des Magnetfeldsensors dem Mess- und Anregungsbereich des Kanals. Beim Befördern der fluiden Probe im Mess- und Anregungsbereich des Kanals wird das Magnetfeld von der zu untersuchenden fluiden Probe modifiziert, wobei der Magnetfeldsensor das modifizierte Magnetfeld erfasst. Die Erfindung betrifft weiterhin ein Verfahren zum Betrieb des erfindungsgemäßen Fluidik-Detektionssystems zur magnetisch-elektrischen Messung einer fluiden Probe.

  • Patent
    DE102018116918 - Offenlegung 16.01.2020; Nachanmeldungen: WO

Permalink: https://www.hzdr.de/publications/Publ-31223
Publ.-Id: 31223


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