Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

"Online First" included
Approved and published publications
Only approved publications

43542 Publications

Triangular-shaped Cu–Zn–In–Se-based nanocrystals with narrow near infrared photoluminescence

Bora, A.; Fu, N.; Saha, A.; Prudnikau, A.; Hübner, R.; Bahmani Jalali, H.; Di Stasio, F.; Gaponik, N.; Lesnyak, V.

Abstract

Tunable optical properties exhibited by semiconductor nanocrystals (NCs) in the near infrared (NIR) spectral region are of particular interest in various applications, such as telecommunications, bioimaging, photodetection, photovoltaics, etc. While lead and mercury chalcogenide NCs do exhibit exemplary optical properties in the NIR, Cu–In–Se (CISe)-based NCs are a suitable environment-friendly alternative to these toxic materials. Several reports of NIR-emitting (quasi)spherical CISe NCs have been published, but their more complex-shaped counterparts remain rather less explored. The emerging anisotropic nanomaterials have gained significant interest owing to their unique optical properties arising due to their specific shape. While several examples of non-spherical Cu–In–S-based NCs have been reported, examples of CISe-based anisotropic NCs are rather scarce, and those with intensive photoluminescence (PL) are not yet developed. In this work, we present a one-pot approach to synthesize quaternary Cu–Zn–In–Se (CZISe) triangular NCs with intensive PL in the NIR region. The NCs synthesized exhibit tetragonal crystal structure and, depending on the reaction conditions, are single triangular particles or stacks of triangular blocks of varied lateral sizes but rather uniform thickness. The synthesis involves the formation of In2Se3 seeds with subsequent incorporation of copper and growth of triangular CISe NCs, followed by the incorporation of zinc and the growth of a ZnS shell. Importantly, the PL band widths of the final core/shell heterostructured NCs are narrow, down to 102 meV, which is a rarely observed characteristic for this class of materials and can be attributed to their anisotropic shape and the absence of thickness and compositional inhomogeneities of their building blocks. The PL of the CZISe/ZnS NCs can be tuned in the range of 1082-1218 nm reaching a quantum yield of up to 40% by varying their size and composition. To the best of our knowledge, this is the farthest and the narrowest PL achieved for CISe-based NCs so far, which widens application perspectives of this material in NIR LEDs, bioimaging, and photovoltaics.

Involved research facilities

Related publications

Permalink: https://www.hzdr.de/publications/Publ-40937


Pressure drop and flooding points of droplet separators at relevant fluid properties

Döß, A.; Schubert, M.; Kryk, H.; Flegiel, F.; Hampel, U.

Abstract

Der Mitriss von Tropfen durch die aufsteigende Dampfphase in Trennkolonnen beeinträchtigt die Trennleistung, Energieeffizienz und Produktqualität erheblich und kann den Betrieb nachgeschalteter Apparate stören. Effiziente Tropfenabscheidung ist daher entscheidend für die Einsparung von Energie und Ressourcen. Zur verlässlichen Modellierung der Abscheidung bei realen Stoffsystemen ist eine Vorhersage mitgerissener Tropfenspektren, Druckverluste sowie der Flutpunkte entscheidend. Verfügbare Experimentaldaten für Tropfenabscheider wie Gestricke, Trägheitsabscheider oder Füllkörper decken jedoch nur einen unzureichenden Teil realer Geometrien und Stoffwerte ab. Insbesondere relevant sind Stoffwerte, die zur Bildung von Kleinsttropfen (< 5 μm) beitragen oder ein Benetzungsverhalten hervorrufen, welches kaum durch gängige Ersatzsysteme wie z. B. Wasser/Luft abgebildet werden kann. Darüber hinaus werden wichtige Einflussfaktoren wie Tropfengrößen und geometrische Parameter der Abscheider in gängigen Modellen bisher ignoriert. Dies führt häufig zu kostenintensiven, überdimensionierten Anlagen und großen Sicherheitsmargen.
In der TERESA-Forschungsanlage am Helmholtz-Zentrum Dresden-Rossendorf wird ein Kältemittelkreislauf mit dem Arbeitsmedium dient 3M™ Novec 649™ betrieben. Bei unterschiedlichen Druckniveaus werden relevante Fluidstoffwerte realisiert: Oberflächenspannungen unter 10 mN/m, hohe Dampfdichten (18 bis 170 kg/m³) bei gleichzeitig großen Dichteunterschieden zur Flüssigphase (887 bis 1450 kg/m³). Durch eine Flash-Verdampfung treten Dampf und Flüssigphase im Gleichstrom in einen vertikalen Testabscheider (DN 300 x 2,3 m) ein, so dass F-Faktoren bis 6 Pa0,5 realisiert werden können. Zusätzlich können über Düsen gezielt Tropfenspektren in die Zweiphasenströmung aufgegeben werden. Die in die Tropfenabscheider eingetragenen Tropfenspektren werden durch ein Strömungsmikroskop erfasst. Die Analyse der Flutpunkte und die Bilanzierung des Mitrisses erfolgt stromabwärts der Abscheider durch Erfassung aller notwendigen Flüssigkeitsströme.
In diesem Beitrag werden Untersuchungen mit verschieden Gestrickabscheidern vorgestellt. Dies umfasst die geometrische Charakterisierung und experimentellen Bestimmung von Porosität, trockenem Druckverlust und Flutpunkten für relevante Stoffwerte. Ein auf Basis dieser Daten entwickeltes praxistaugliches Modell wird ebenso präsentiert, bei dem viskose und turbulente Effekte beim Druckverlust berücksichtigt werden. Zudem wurden die Flutpunkte mehrerer Gestricke in der TERESA-Versuchsanlage für drei verschiedene Stoffeigenschaften-Kombinationen analysiert. Die Ergebnisse werden mit bestehenden Vorhersagemethoden wie dem Sherwood-Diagramm und der K-Wert-Methode verglichen.
Die Arbeiten im Rahmen des Projektes GeTReal werden durch das Bundesministerium für Wirtschaft und Klimaschutz (BMWK) über die Arbeitsgemeinschaft industrieller Forschungsvereinigungen „Otto von Guericke“ e.V. (AiF) gefördert (IGF-Vorhaben: 01IF22594N).

Keywords: Droplet separation; Wire mesh demisters; Pressure drop; Thermal separation

Involved research facilities

  • TOPFLOW Facility
  • TERESA
  • Lecture (Conference)
    Jahrestreffen der DECHEMA/VDI-Fachgruppe Fluidverfahrenstechnik, 03.-05.02.2025, Bochum, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40935


EURAD state-of-the-art report: development and improvement of numerical methods and tools for modeling coupled processes in the field of nuclear waste disposal

Claret, F.; Prasianakis, N. I.; Baksay, A.; Lukin, D.; Pepin, G.; Ahusborde, E.; Amaziane, B.; Bátor, G.; Becker, D.; Bednár, A.; Béreš, M.; Bérešová, S.; Böthi, Z.; Brendler, V.; Brenner, K.; Březina, J.; Chave, F.; Churakov, S. V.; Hokr, M.; Horák, D.; Jacques, D.; Jankovský, F.; Kazymyrenko, C.; Koudelka, T.; Kovács, T.; Krejčí, T.; Kruis, J.; Laloy, E.; Landa, J.; Ligurský, T.; Lipping, T.; López-Vázquez, C.; Masson, R.; Meeussen, J. C. L.; Mollaali, M.; Mon, A.; Montenegro, L.; Pisani, B.; Poonoosamy, J.; Pospiech, S. I.; Saâdi, Z.; Samper, J.; Samper-Pilar, A.-C.; Scaringi, G.; Sysala, S.; Yoshioka, K.; Yang, Y.; Zuna, M.; Kolditz, O.

Abstract

The Strategic Research Agenda (SRA; https://www.ejp-eurad.eu/publications/eurad-sra) of the European Joint Programme on Radioactive Waste Management (EURAD; https://www.ejp-eurad.eu/) describes the scientific and technical domains and sub-domains and knowledge management needs of common interest between EURAD participant organizations. Theme number 7 is entitled “Performance assessment, safety case development and safety analyses.” A list of research and development priorities and activities of common interest to be addressed within EURAD for theme 7 have been established. Amongst others, the Understanding and modelling of multi-physical Thermo-Hydro-Mechanical-Chemical coupled processes (THMC) occurring in radioactive waste disposal is a major and permanent issue to support optimization of design and safety case abstraction. To tackle this challenge a research work package entitled “DONUT: Development and improvement of numerical methods and tools for modelling coupled processes” has been conducted within the EURAD join programming initiative. The purpose of this work package is to improve/develop methods or numerical tools in order to go a step further in development of (i) relevant, performant and cutting-edge numerical methods that can easily be implemented in existing or new tools, in order to carry out high-performance computing to facilitate the study of highly coupled processes in large systems, (ii) numerical scale transition schemes for coupled processes, (iii) innovative numerical methods to carry out uncertainty and sensitivity analyses. In this paper the work carried out within the DONUT work package is put in perspective regarding the existing concept and literature on the field. It does not pretend to be exhaustive but rather to put emphasis on particular issues tackled during the project.

Permalink: https://www.hzdr.de/publications/Publ-40923


Heat transfer enhancement for nucleate boiling via microlayer disruption on micro-pillar arrayed surfaces

Zhang, J.; Li, R.; Vadlamudi, S. R. G.; Pang, C.; Hampel, U.; Ding, W.

Abstract

Surface modifications have demonstrated significant potential in enhancing heat transfer in nucleate boiling, yet their impact on microlayer evaporation—a key heat transfer mechanism—remains less understood. In this work, we performed isolated bubble nucleate boiling experiments with micro-pillar arrayed surfaces to study the microlayer heat transfer. We initially analyzed the bubble dynamics, including growth dynamics and shape evolution throughout the entire bubble life cycle on these surfaces in detail. The results show that bubble dynamics differ considerably across different surfaces under the same surface superheat, primarily due to differences in microlayer evaporation. We then statistically quantify the bubble growth dynamics to evaluate the microlayer heat transfer performance. Importantly, we found that the experimental results align closely with the inference on the microlayer heat transfer derived from our previous simulation results of initial microlayer morphology on similar surfaces. This alignment allowed us to experimentally confirm the existence of two distinctive microlayer morphologies on micro-pillar arrayed surfaces, as observed in our previous simulations: the disturbed and the disrupted microlayer. We demonstrated that the microlayer morphology governs its heat transfer performance and, consequently, bubble dynamics during the entire bubble life cycle. Notably, our findings suggest the existence of a critical microlayer thickness, which can be achieved through surface modifications, to sustain a high evaporation rate throughout the bubble life cycle. To optimize surface design, we proposed a microlayer morphology concept that links the microlayer morphology with the corresponding heat transfer performance on micro-pillar arrayed surfaces.

Keywords: Nucleate boiling; Microlayer morphology; Micro-pillar arrayed surface; Heat transfer; Surface engineering

Permalink: https://www.hzdr.de/publications/Publ-40921


Data publication: Benchmarking a magnon-scattering reservoir with modal and temporal multiplexing

Heins, C.; Kim, J.-V.; Körber, L.; Faßbender, J.; Schultheiß, H.; Schultheiß, K.

Abstract

This data publication contains the data for the publication "Benchmarking a magnon-scattering reservoir with modal and temporal". The dataset is structured in folders corresponding to the different figures in the paper. The parent folder contains the full BLS spectrum and the input used to generate that spectrum. Folder Fig2 contains the experimental data measured with Brillouin-light-scattering microscopy integrated for the measured positions. Fig3 and Fig4 contain the extraction and evaluation. Each Folder contains additional information about their content.

Keywords: reservoir computing; spin wave; magnon; magnetic vortex; nonlinearity; Brillouin light scattering

Involved research facilities

Related publications

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40920


High-Performance Visible-to-SWIR Photodetector Based on the Layered WS2 Heterojunction with Light-Trapping Pyramidal Black Germanium

Bhattacharya, K.; Chaudhary, N.; Bisht, P.; Satpati, B.; Manna, S.; Singh, R.; Mehta, B. R.; Georgiev, Y.; Das, S.

Abstract

This study presents a layered transition metal dichalcogenide/black germanium (b-Ge) heterojunction photodetector that exhibits superior performance across a broad spectrum of wavelengths spanning from visible (vis) to shortwave infrared (SWIR). The photodetector includes a thin layer of b-Ge, which is created by wet etching of germanium (Ge) wafer to form submicrometer pyramidal structures. On top of this b-Ge layer, the WS2 thin film is deposited using pulsed laser deposition. In comparison to conventional germanium, b-Ge absorbs about 25% more light between 850 and 1750 nm wavelengths. The WS2/b-Ge photodetector has a peak photoresponsivity of 0.65 A/W, which is more than twice the photoresponsivity of the WS2/Ge photodetector at 1540 nm. Additionally, it shows better responsivity and response speed compared with other similar state-of-the-art photodetectors.
Such an improvement in the performance of the device is credited to the lighttrapping effect enabled by the germanium pyramids. Theoretical simulations employing the finite-difference time-domain technique help validate the concept. This novel photodetector holds promise for efficient detection of light across the vis to SWIR spectrum.

Keywords: layered TMD; germanium pyramids; black germanium; heterojunction photodetector; light trapping; FDTD

Involved research facilities

Related publications

Downloads

  • Secondary publication expected from 31.08.2025

Permalink: https://www.hzdr.de/publications/Publ-40911


Flexible, printed and eco-sustainable magnetic field sensors

Zabila, Y.; Guo, L.; Sergio Oliveros Mata, E.; Xu, R.; Makarov, D.

Abstract

Magnetic field sensors are integral part of our household electronics, automation and IoT. Conventional magnetic field sensors are rigid components prepared on Si wafers. We realise biocompatible, biodegradable and self-healable magnetosensitive devices using printed and flexible electronics technologies. With these activities, we minimise electronic waste and bring magnetoelectronics to new application fields in medical implants, health monitoring and human-machine interfaces.

Composites consisting of magnetic fillers in polymers and elastomers enable new application scenarios in soft robotics [1,2] and reconfigurable actuation [3]. Furthermore, they gave birth to the novel technology of solution processable magnetic field sensors. We demonstrate that printed magnetoelectronics can be stretchable, skin-conformal, capable of detection of low magnetic fields and withstand extreme mechanical deformations [4,5]. We feature the potential of our skin-conformal sensors in augmented reality settings for remote and touchless control of virtual objects, scrolling electronic documents and zooming maps. We put forth technology to realise magnetic field sensors, which can be printed and self-heal upon mechanical damage [6]. This opens exciting perspectives for magnetoelectronics in smart wearables, interactive printed electronics. Moreover, this research motivates further explorations towards the realization of eco-sustainable magnetoelectronics. For the latter, we will discuss biocompatible and biodegradable magneto sensitive devices, which can help to minimise electronic waste and bring magnetoelectronics to new application fields in medical implants and health monitoring.

REFERENCES
[1] Y. Liu, G. Lin, M. Medina, M. G. Noguera, D. Makarov, and D. Jin, “Responsive magnetic nanocomposites for intelligent shape-morphing microrobots,” ACS Nano vol. 17, pp. 8899-8917, May 2023.
[2] M. Richter, J. Sikorski, P.Makushko, Y. Zabila, V. K. Venkiteswaran, D. Makarov, and S. Misra, “Locally addressable energy efficient actuation of magnetic soft actuator array systems,” Advanced Science vol. 10, pp. 2302077, Aug. 2023.
[3] M. Ha, G. S. Cañón Bermúdez, J. A.-C. Liu, E. S. Oliveros Mata, B. A. Evans, J. B. Tracy, and D. Makarov, "Reconfigurable magnetic origami actuators with on-board sensing for guided assembly," Adv. Mater. vol. 33, pp. 2008751, Jun. 2021.
[4] M. Ha, G. S. Cañón Bermúdez, T. Kosub, I. Mönch, Y. Zabila, E. S. Oliveros Mata, R. Illing, Y. Wang, J. Fassbender, and D. Makarov, “Reconfigurable magnetic origami actuators with on-board sensing for guided assembly,” Advanced Materials vol. 33, pp. 2005521, Mar 2021.
[5] E. S. Oliveros Mata, C. Voigt, G. S. Cañón Bermúdez, Y. Zabila, N. M. Valdez-Garduño, M. Fritsch, S. Mosch, M. Kusnezoff, J. Fassbender, M. Vinnichenko, and D. Makarov, "Dispenser printed bismuth-based magnetic field sensors with non-saturating large magnetoresistance for touchless interactive surfaces," Adv. Mater. Technol. vol. 7, pp. 2200227, Oct. 2022.
[6] R. Xu, G. S. Cañón Bermúdez, O. V. Pylypovskyi, O. M. Volkov, E. S. Oliveros Mata, Y. Zabila, R. Illing, P. Makushko, P. Milkin, L. Ionov, J. Fassbender, and D. Makarov, "Self-healable printed magnetic field sen-sors using alternating magnetic fields," Nature Communications vol. 13, pp. 6587, Nov. 2022.

  • Invited lecture (Conferences)
    RAEng workshop on Alternative device concepts for flexible electronics, 25.11.2024, Royal Academy of Engineering, London, United Kingdom

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40910


Multifunctional smart skins for human machine interfaces and robotics

Zabila, Y.

Abstract

Mechanically soft electronics relies on functional elements, which are prepared on flexible and elastic membranes, allowing for bending, folding, or twisting. This technology enables applications in smart skins, smart textiles and soft robotics. Crucial to flexible interactive on-skin and wearable electronics are flexible magnetic field sensors [1], facilitating the monitoring of various types of motion. Typically, magnetic thin films are employed in flexible magnetoelectronics for detecting in-plane magnetic fields [2-4]. To enhance sensitivity to out-of-plane magnetic fields [5], Bi-based Hall effect sensors have demonstrated efficiency in smart wearables and electromobility applications [6].

Semi-metallic Bi thin films exhibit exceptionally high magnetoresistance (MR) and a robust Hall effect, even at room temperature, particularly when patterned to a small lateral size. Our research delves into the remarkable strain sensitivity of Bi thin films to create a multifunctional flexible device capable of simultaneously measuring strain and magnetic fields. We fabricate Bi thin films of different thickness on ultrathin polyimide foils. These sensors prove their mechanically stable, enduring severe mechanical bending with radii as small as 1 mm for 10,000 bending cycles. We introduce and validate a measurement sequence based on the spinning current approach, effectively decoupling signals measured by a single sensor element in transversal and longitudinal resistance channels. Furthermore, we have developed a method to analyze the measured transversal and longitudinal resistances, enabling the assessment of the out-of-plane component of the magnetic field (Hall effect)
and vector components of in-plane strain (piezoresistive effect). These sensors find application as a component of smart skin for soft robotics and human-machine interfaces. In this presentation, we will demonstrate the key aspects linking the fundamental properties of Bi thin films to their practical implementation in flexible sensor devices for simultaneous strain and magnetic field sensing.

References
[1] G.S. Cañón Bermúdez et al., Magnetosensitive E-Skins for Interactive Devices. Adv. Funct. Mater. 31, 2007788 (2021).
[2] R. Xu, Y. Zabila et al., Self-healable printed magnetic field sensors using alternating magnetic fields. Nature Communications 13, 6587 (2022).
[3] M. Ha, Y. Zabila et al., Printable and Stretchable Giant Magnetoresistive Sensors for Highly Compliant and Skin-conformal Electronics. Adv. Mater. 33, 2005521 (2021).
[4] E. S. Oliveros Mata, Y. Zabila et al., Dispenser printed bismuth-based magnetic field sensors with nonsaturating large magnetoresistance for touchless interactive surfaces. Adv. Mater. Technol. 7, 2200227 (2022).
[5] P. Makushko, Y. Zabila et al., Flexible Magnetoreceptor with Tunable Intrinsic Logic for On-Skin Skin Touchless Human-Machine Interfaces. Adv. Funct. Mater. 31, 2101089 (2021).
[6] M. Melzer, Y. Zabila et al., Wearable Magnetic Field Sensors for Flexible Electronics. Adv. Mater. 27, 1274 (2015).

  • Invited lecture (Conferences)
    iSIM 2024 - International Symposium on Integrated Magnetics, 04.-05.05.2024, Rio de Janeiro, Brazil

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40909


Flexible, printed and eco-sustainable magnetic field sensors

Zabila, Y.; Guo, L.; Sergio Oliveros Mata, E.; Xu, R.; Makarov, D.

Abstract

Magnetic field sensors are integral part of our household electronics, automation and IoT. Conventional magnetic field sensors are rigid components prepared on Si wafers. We realise biocompatible, biodegradable and self-healable magnetosensitive devices using printed and flexible electronics technologies. With these activities, we minimise electronic waste and bring magnetoelectronics to new application fields in medical implants, health monitoring and human-machine interfaces.
Composites consisting of magnetic fillers in polymers and elastomers enable new application scenarios in soft robotics [1,2] and reconfigurable actuation [3]. Furthermore, they gave
birth to the novel technology of solution processable magnetic field sensors. We demonstrate that printed magnetoelectronics can be stretchable, skin-conformal, capable of detection of low magnetic fields and withstand extreme mechanical deformations [4,5]. We feature the potential of our skinconformal sensors in augmented reality settings for remote and touchless control of virtual objects, scrolling electronic documents and zooming maps. We put forth technology to realise magnetic field sensors, which can be printed and selfheal upon mechanical damage [6]. This opens exciting perspectives for magnetoelectronics in smart wearables, interactive printed electronics. Moreover, this research motivates further explorations towards the realization of ecosustainable magnetoelectronics. For the latter, we will discuss biocompatible and biodegradable magneto sensitive devices, which can help to minimise electronic waste and bring magnetoelectronics to new application fields in medical implants and health monitoring.

REFERENCES
[1] Y. Liu, G. Lin, M. Medina, M. G. Noguera, D. Makarov, and D. Jin,
“Responsive magnetic nanocomposites for intelligent shape-morphing
microrobots,” ACS Nano vol. 17, pp. 8899-8917, May 2023.
[2] M. Richter, J. Sikorski, P.Makushko, Y. Zabila, V. K. Venkiteswaran,
D. Makarov, and S. Misra, “Locally addressable energy efficient
actuation of magnetic soft actuator array systems,” Advanced Science vol.
10, pp. 2302077, Aug. 2023.
[3] M. Ha, G. S. Cañón Bermúdez, J. A.-C. Liu, E. S. Oliveros Mata, B. A.
Evans, J. B. Tracy, and D. Makarov, "Reconfigurable magnetic origami
actuators with on-board sensing for guided assembly," Adv. Mater. vol. 33,
pp. 2008751, Jun. 2021.
[4] M. Ha, G. S. Cañón Bermúdez, T. Kosub, I. Mönch, Y. Zabila, E. S.
Oliveros Mata, R. Illing, Y. Wang, J. Fassbender, and D. Makarov,
“Reconfigurable magnetic origami actuators with on-board sensing for
guided assembly,” Advanced Materials vol. 33, pp. 2005521, Mar 2021.
[5] E. S. Oliveros Mata, C. Voigt, G. S. Cañón Bermúdez, Y. Zabila, N. M.
Valdez-Garduño, M. Fritsch, S. Mosch, M. Kusnezoff, J. Fassbender, M.
Vinnichenko, and D. Makarov, "Dispenser printed bismuth-based
magnetic field sensors with non-saturating large magnetoresistance for
touchless interactive surfaces," Adv. Mater. Technol. vol. 7, pp. 2200227,
Oct. 2022.
[6] R. Xu, G. S. Cañón Bermúdez, O. V. Pylypovskyi, O. M. Volkov, E. S.
Oliveros Mata, Y. Zabila, R. Illing, P. Makushko, P. Milkin, L. Ionov,
J. Fassbender, and D. Makarov, "Self-healable printed magnetic field sensors using alternating magnetic fields," Nature Communications vol. 13,
pp. 6587, Nov. 2022.

Keywords: flexible magnetoelectronics; printed magnetoelectronics; biocompatible magnetic field sensors

  • Open Access Logo Invited lecture (Conferences)
    Intermag 2024, IEEE International Magnetics Conference, 05.-10.05.2024, Rio de Janeiro, Brazil

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40908


A new pairwise encounter probability estimator for range-resident animals

Calabrese, J.; Martinez Garcia, R.; Colombo, E. H.; Simoes Silva, I. M.; Menezes, J.; Fleming, C.

Abstract

Direct encounters, which can occur when two animals come within a threshold distance of each another, underpin many ecological processes including predation, mating, contest competition, territory formation, and disease transmission. The probability of encounter is therefore of fundamental quantity, and has historically been quantified from animal tracking data via two classes of metrics that feature contrasting strengths and weaknesses. Trajectory-based methods estimate the frequency of simultaneous location observations between two individuals that are within a threshold distance, d. In contrast, distribution-based methods use home range overlap as a proxy for encounter potential. While trajectory-based metrics directly quantify the probability of encounter, they are sensitive to the sampling frequency and yield underestimates when data are sparse, often failing to detect any encounters. In contrast, home-range-based metrics have good statistical properties, including insensitivity to sampling frequency, but are not straightforwardly related to encounter probability. Here, we introduce a distribution-based estimator of the probability of encounter. Using mathematical arguments, simulated data, and empirical case studies, we show that, like trajectory-based methods, our metric directly and accurately estimates encounter probability, while also displaying the sampling insensitivity of methods based on home range overlap. Furthermore, our probability of encounter estimator features reliable confidence intervals, and is implemented in and fully integrated with the ctmm R package (v1.2+) for movement analysis.

Keywords: animal tracking data; continuous-time models; ctmm; encounter probability; species interactions

  • Lecture (Conference)
    BioMove Symposium 2024, 01.03.2024, Potsdam, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40907


A Novel, Range-Distribution-Based Estimator of Pairwise Encounter Probabilities

Calabrese, J.; Martinez Garcia, R.; Menezes, J.; Medici, P.; Morato, R.; Fleming, C.

Abstract

Direct encounters, which can occur when two animals come within a threshold distance of each another, underpin many ecological processes including predation, mating, contest competition, territory formation, and disease transmission. The probability of encounter is therefore of fundamental quantity, and has historically been quantified from animal tracking data via two classes of metrics that feature contrasting strengths and weaknesses. Trajectory-based methods estimate the frequency of simultaneous location observations between two individuals that are within a threshold distance, d. In contrast, distribution-based methods use home range overlap as a proxy for encounter potential. While trajectory-based metrics directly quantify the probability of encounter, they are sensitive to the sampling frequency and yield underestimates when data are sparse. In contrast, home-range-based metrics have good statistical properties, including insensitivity to sampling frequency, but are not straightforwardly related to encounter probability. Here, we introduce a distribution-based estimator of the probability of encounter. Using mathematical arguments, simulated data, and empirical case studies, we show that, like trajectory-based methods, our metric directly and accurately estimates encounter probability, while also displaying the sampling insensitivity of methods based on home range overlap. Furthermore, our probability of encounter estimator features reliable confidence intervals, and is implemented in and fully integrated with the ctmm R package (v1.2+) for movement analysis.

  • Invited lecture (Conferences)
    Brin Mathematics Research Center: Applied Stochastic Processes for Encounter Problems, 06.02.2024, College Park, USA

Permalink: https://www.hzdr.de/publications/Publ-40906


Data publication for "Feasibility of Na-Zn batteries for grid-scale energy storage: insights from in situ studies"

Sarma, M.; Shevchenko, N.; Weber, N.; Weier, T.

Abstract

This dataset contains unprocessed results from the X-ray radiography imaging of high temperature molten salt Na-Zn battery.

The folders are structured as follows:

- 01 to 03 correspond to radiography results,

- 04 corresponds to comparison of long-term cycling of two different batteries.

01 to 03 has subfolder structure as follows:

- 01 has the raw files in 16bit tiff format,

- 02 has unprocessed png files with fixed contrast and overlay of cycling data for each time step,

- 03 is an mp4 video of png files made with ffmpeg,

- 04 is the recorded cycling data.

The raw data has the Date and time as title.

There is 167 second offset between radiographs and electrochemical data (one has to add the offset time to join both data sets).

Cycling data has been exported as .txt from EC-Lab V11.61 with following variables:

*time/s* *Ewe/V* *I/mA* *(Q-Q0)/mA.h* *cycle number* *mode* *ox/red*

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 963599.

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40905


Interfacing Single Layer Graphene with Ferromagnets for Terahertz Spintronics

Koyun Yücel, H. N.; Salikhov, R.; Winnerl, S.; Lindner, J.; Ünlü, C. G.; Helm, M.

Abstract

Efficient broadband electronic frequency multipliers and modulators for the terahertz (THz) frequency range require integration of a highly nonlinear material like graphene (Gr) in an electronic device. In ferromagnetic (FM) materials, on the other hand, spin waves or magnons in a FM layer can be excited using THz light. Combining these materials in a Gr/FM heterostructure allows one to generate and inject a spin-polarized current into Gr, which is one goal of Gr-based spintronics. However, a major limitation arises in the presence of disorder and impurities on Gr during fabrication of a prototypical spintronic device, namely during metal deposition [1]. It has been shown that the level of structural damage can be reduced after the sputtering process on Gr by changing of sputtering configuration [2]. We follow this approach by depositing 2 nm of Permalloy (Py) onto single-layer graphene (SLG) with a change of the distance, which was 20 cm between target and substrate, and using SLG which was produced by chemical vapor deposition. We utilize two configurations, the standard configuration with the SLG facing the target and a flipped configuration, in which the backside of the SLG faces the target. Raman spectoscopy was carried out on the fabricated Si/SiO2/Gr/Py composite samples. Figure 1 compares the Raman spectra of SLG deposited in the two configurations. The characteristic D, G and 2D major peaks of Gr can be observed at around 1336 cm−1, 1582 cm−1 and 2678 cm−1, respectively. The Lorentzian shape of the 2D peak as well as the I2D/IG ratio of the samples for both configurations indicates a monolayer. The peak at 1336 cm−1 corresponds to the D-band, which is attributed to the presence of undesirable impurities in the structure. Since the D peak comes into sight in the presence of structural defects and disorders, the appearance of the higher D peak indicates that the deposition of Py induces disorder in the structure, especially in the unflipped deposition configuration. The ID/IG ratio which is used to assess the quality of the Gr was calculated as 0.31 for the flipped configuration (lower than the unflipped configuration, was 1.41) therefore this ratio implies a lower number of defects in the Gr. We see that the weak intensity of D-peak in the flipped configuration provides higher quality Gr and it was observed that even after Py deposition, quality of Gr can be maintained using the flipped configuration.

Keywords: Single Layer Graphene; Spin-polarized current; Graphene/Ferromagnet heterostructure

  • Open Access Logo Poster
    The 25th International Conference on the Electronic Properties of Two-Dimensional Systems (EP2DS-25) and 21st International Conference on Modulated Semiconductor Structures (MSS-21), 09.-14.07.2023, Grenoble, France

Permalink: https://www.hzdr.de/publications/Publ-40903


Optimizing Subwavelength Metallic Gratings For Enhanced Spintronic Terahertz Frequency Conversion Efficiency

Koyun Yücel, H. N.; Salikhov, R.; Fowley, C.; Lindner, J.; Winnerl, S.; Erbe, A.; Helm, M.; Faßbender, J.; Kovalev, S.

Abstract

Terahertz (THz) spintronics, operating on picosecond timescales, involves the generation and control of non-equilibrium electron spin states within the THz frequency regime. Efficient generation and control of spin currents launched by THz radiation with subsequent ultrafast spin-to-charge conversion is the current challenge for the next-generation of high-speed communication and data processing units. Recent studies have shown that THz light can efficiently drive coherent spin currents in nanometer-thick ferromagnet (FM)/heavy-metal (HM) heterostructures, primarily due to demagnetization process of FM and the ultrafast spin Seebeck effect arising from a THz-induced temperature imbalance between electronic and magnonic systems and rapid electron-phonon relaxation. Owing to the fact that the electron-phonon relaxation time is comparable (or smaller) to the period of a THz wave, the induced spin current from each half cycle of the THz wave results in THz second harmonic generation (TSHG) and THz optical rectification. In this study, we explore the potential of utilizing subwavelength-sized gold periodic arrays with a grating period smaller than the THz wavelength to enhance local spin currents, thereby improving the efficiency of THz frequency conversion. By fabricating different gratings with varying widths of Au stripes and spacing between them, we aim to achieve efficient spintronic THz frequency conversion in the near-field regime. Our findings indicate that power efficiency increases as the gap size decreases, resulting in a nine-fold enhancement at a 2 μm gap size.

Keywords: Terahertz spintronics; ferromagnet (FM)/heavy-metal (HM) heterostructures; Spin Current; Terahertz second harmonic generation

Involved research facilities

  • T-ELBE
  • Poster
    Optical Terahertz Science and Technology, 08.-12.04.2024, Marburg, Germany

Permalink: https://www.hzdr.de/publications/Publ-40902


Advancing the Efficiency of Spintronic Terahertz Frequency Conversion

Koyun Yücel, H. N.; Salikhov, R.; Fowley, C.; Lindner, J.; Winnerl, S.; Erbe, A.; Faßbender, J.; Helm, M.; Kovalev, S.

Abstract

Terahertz (THz) spintronics, operating on picosecond timescales, involves the generation and control of non equilibrium electron spin states within the THz frequency regime. Recent studies have shown that THz light can efficiently drive coherent spin currents in nanometer-thick ferromagnet (FM)/heavy-metal (HM) heterostructures, primarily due to demagnetization process of FM and the ultrafast spin Seebeck effect. Owing to the fact that the electronphonon relaxation time is comparable (or smaller) to the period of a THz wave, the induced spin current from each half cycle of the THz wave results in THz second harmonic generation (TSHG) and THz optical rectification. In this study, we explore the potential of utilizing subwavelength-sized gold periodic arrays with a grating period smaller than the THz wavelength to enhance local spin currents, thereby improving the efficiency of THz frequency conversion.

Keywords: Terahertz Second Harmonic Generation; Efficiency; Spin Current; Ferromagnet/Heavy Metal Heterostructure

Involved research facilities

  • T-ELBE
  • Lecture (Conference)
    87. Annual Meeting of DPG and DPG-Frühjahrstagung (DPG Spring Meeting) of the Condensed Matter Section (SKM), 17.-22.03.2024, Berlin, Germany

Permalink: https://www.hzdr.de/publications/Publ-40900


Early collapse of vegetation cover induced by nonreciprocal interactions

Pinto Ramos, D. I.

Abstract

Understanding large-scale vegetation cover dynamics has required the development of several mathematical models to predict its future in a changing climate. In these models, it is the rule rather than the exception that simplifications are made for mathematical simplicity and tractability of the model outcomes. Homogeneity and isotropy are assumptions that have allowed the community to develop a robust theory for the future of vegetation, and how this future is related to the phenomenon of spatial pattern formation. Nevertheless, several authors have extended the models beyond these assumptions, finding unexpected phenomena, such as the survivance of vegetation beyond the tipping point or the prediction of spatial structures not present in previous theories. In this work, we explore the effect of nonreciprocal interactions, which are a form of non-isotropy, combined with the finite region of the landscape that supports patterns modeled by boundary conditions for the model. We find that enough nonreciprocity can overcome the resilience induced by spatial patterns, and anti-intuitively, a homogeneous cover can become more resilient against environmental changes. Nonreciprocity always reduces the system's resilience, but introduces an interplay between the nonreciprocity and the competition range of plants that control the tipping point nontrivially. Our findings highlight the relevance of often ignored ingredients in mathematical models of vegetation cover.

  • Invited lecture (Conferences)
    School on Biological Physics across Scales: Pattern Formation, 11.-22.11.2024, ICTP-SAIFR, São Paulo, Brazil

Permalink: https://www.hzdr.de/publications/Publ-40898


A Cu3BHT-Graphene van der Waals Heterostructure with Strong Interlayer Coupling for Highly Efficient Photoinduced Charge Separation

Wang, Z.; Fu, S.; Zhang, W.; Liang, B.; Liu, T.-J.; Hambsch, M.; Pöhls, J. F.; Wu, Y.; Zhang, J.; Lan, T.; Li, X.; Qi, H.; Polozij, M.; Mannsfeld, S. C. B.; Kaiser, U.; Bonn, M.; Thomas Weitz, R.; Heine, T.; Parkin, S. S. P.; Wang, H. I.; Dong, R.; Feng, X.

Abstract

Two-dimensional van der Waals heterostructures (2D vdWhs) are of significant interest due to their intriguing physical properties critically defined by the constituent monolayers and their interlayer coupling. Synthetic access to 2D vdWhs based on chemically tunable monolayer organic 2D materials remains challenging. Herein, the fabrication of a novel organic–inorganic bilayer vdWh by combining π-conjugated 2D coordination polymer (2DCP, i.e., Cu3BHT, BHT = benzenehexathiol) with graphene is reported. Monolayer Cu3BHT with detectable µm2-scale uniformity and atomic flatness is synthesized using on-water surface chemistry. A combination of diffraction and imaging techniques enables the determination of the crystal structure of monolayer Cu3BHT with atomic precision. Leveraging the strong interlayer coupling, Cu3BHT-graphene vdWh exhibits highly efficient photoinduced interlayer charge separation with a net electron transfer efficiency of up to 34% from Cu3BHT to graphene, superior to those of reported bilayer 2D vdWhs and molecular-graphene vdWhs. This study unveils the potential for developing novel 2DCP-based vdWhs with intriguing physical properties.

Keywords: connductive 2D coordination polymers; 2D van der Waals heterostructures; interlayer coupling; charge separation

Permalink: https://www.hzdr.de/publications/Publ-40897


Temperature Effects of Nuclear and Electronic Stopping Power on Si and C Radiation Damage in 3C-SiC

Kucal, E.; Józwik, P.; Mieszczynski, C.; Heller, R.; Akhmadaliev, S.; Dufour, C.; Czerski, K.

Abstract

Silicon carbide has been considered a material for use in the construction of advanced hightemperature
nuclear reactors. However, one of the most important design issues for future reactors is
the development of structural defects in SiC under a strong irradiation field at high temperatures. To
understand how high temperatures affect radiation damage, SiC single crystals were irradiated at
room temperature and after being heated to 800 °C with carbon and silicon ions of energies ranging
between 0.5 and 21 MeV. The number of displaced atoms and the disorder parameters have been
estimated by using the channeling Rutherford backscattering spectrometry. The experimentally
determined depth profiles of induced defects at room temperature agree very well with theoretical
calculations assuming its proportionality to the electronic and nuclear-stopping power values. On
the other hand, a significant reduction in the number of crystal defects was observed for irradiations
performed at high temperatures or for samples annealed after irradiation. Additionally, indications
of saturation of the crystal defect concentration were observed for higher fluences and the irradiation
of previously defected samples.

Keywords: radiation damage; stopping power; Rutherford backscattering; ion channeling

Involved research facilities

Related publications

Permalink: https://www.hzdr.de/publications/Publ-40896


The n_TOF facility at CERN

Tagliente, G.; Aberle, O.; Alcayne, V.; Amaducci, S.; Andrzejewski, J.; Babiano-Suarez, V.; Bacak, M.; Balibrea Correa, J.; Bernardes, A. P.; Berthoumieux, E.; Beyer, R.; Boromiza, M.; Bosnar, D.; Caamaño, M.; Calviño, F.; Calviani, M.; Cano-Ott, D.; Casanovas, A.; Castelluccio, D. M.; Cerutti, F.; Cescutti, G.; Chasapoglou, S.; Chiaveri, E.; Claps, G.; Colombetti, P.; Colonna, N.; Console Camprini, P.; Cortés, G.; Cortés-Giraldo, M. A.; Cosentino, L.; Cristallo, S.; Dellmann, S.; Diacono, D.; Di Castro, M.; Diakaki, M.; Dietz, M.; Domingo-Pardo, C.; Dressler, R.; Dupont, E.; Durán, I.; Eleme, Z.; Eslami, M.; Fargier, S.; Fernández-Domínguez, B.; Finocchiaro, P.; Furman, V.; Gandhi, A.; García-Infantes, F.; Gawlik-Ramięga, A.; Gervino, G.; Gilardoni, S.; González-Romero, E.; Goula, S.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Gustavino, C.; Heyse, J.; Hillman, W.; Jenkins, D. G.; Jericha, E.; Junghans, A.; Kadi, Y.; Kaperoni, K.; Kokkoris, M.; Koll, D.; Kopatch, Y.; Krtička, M.; Kyritsis, N.; Ladarescu, I.; Lederer-Woods, C.; Lerendegui-Marco, J.; Lerner, G.; Manna, A.; Martínez, T.; Masi, A.; Massimi, C.; Mastinu, P.; Mastromarco, M.; Maugeri, E. A.; Mazzone, A.; Mendoza, E.; Mengoni, A.; Michalopoulou, V.; Milazzo, P. M.; Mucciola, R.; Musacchio-Gonzalez, E.; Musumarra, A.; Negret, A.; Pérez de Rada, A.; Pérez-Maroto, P.; Patronis, N.; Pavón-Rodríguez, J. A.; Pellegriti, M. G.; Perkowski, J.; Petrone, C.; Piersanti, L.; Pirovano, E.; Plaza del Olmo, J.; Pomp, S.; Porras, I.; Praena, J.; Quesada, J. M.; Reifarth, R.; Rochman, D.; Romanets, Y.; Rooney, A.; Rubbia, C.; Sánchez-Caballero, A.; Sabaté-Gilarte, M.; Scarpa, D.; Schillebeeckx, P.; Schumann, D.; Smith, A. G.; Sosnin, N. V.; Spelta, M.; Stamati, M. E.; Tamburrino, A.; Tarifeño-Saldivia, A.; Tarrío, D.; Torres-Sánchez, P.; Tosi, S.; Tsiledakis, G.; Valenta, S.; Vaz, P.; Vecchio, G.; Vescovi, D.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Weiss, C.; Woods, P. J.; Wright, T.; Žugec, P.

Abstract

The neutron Time-of-Flight (TOF) research facility at CERN, n_TOF, has been a pioneering platform for neutron cross-section measurements since its inception in 2001. It boasts three distinct experimental areas, each tailored to address a specific range of neutron energies. This paper delves into the intricacies of the n_TOF facility, including its recent upgrade during the Long Shutdown 2 (LS2) at CERN. Additionally, it highlights the key characteristics of the detectors employed for capture and fission cross-section measurements, paving the way for future research endeavors.

Keywords: CERN n_ToF

Permalink: https://www.hzdr.de/publications/Publ-40895


Experimental setup of the 239Pu neutron capture and fission cross-section measurements at n_TOF, CERN

Sanchez-Caballero, A.; Alcayne, V.; Andrzejewski, J.; Cano-Ott, D.; Cardinaels, T.; Dries, P.; Gawlik-Ramiega, A.; González-Romero, E.; Heyse, J.; Leinders, G.; Martínez, T.; Mendoza, E.; Moens, A.; Pérez de Rada, A.; Perkowski, J.; Plompen, A.; Paradela, C.; Schillebeeckx, P.; Sibbens, G.; van Hecke, K.; Vanaken, K.; Vanleeuw, D.; Verguts, K.; Verwerft, M.; Wynants, R.; Aberle, O.; Altieri, S.; Amaducci, S.; Babiano-Suarez, V.; Bacak, M.; Balibrea Correa, J.; Beltrami, C.; Bennett, S.; Bernardes, A.-P.; Berthoumieux, E.; Beyer, R.; Boromiza, M.; Bosnar, D.; Caamaño, M.; Calviño, F.; Calviani, M.; Casanovas, A.; Castelluccio, D.; Cerutti, F.; Cescutti, G.; Chasapoglou, S.; Chiaveri, E.; Colombetti, P.; Colonna, N.; Console Camprini, P.; Cortés, G.; Cortés-Giraldo, M.; Cosentino, L.; Cristallo, S.; Dellmann, S.; Di Castro, M.; Di Maria, S.; Diakaki, M.; Dietz, M.; Domingo-Pardo, C.; Dressler, R.; Dupont, E.; Durán, I.; Eleme, Z.; Fargier, S.; Fernández, B.; Fernández-Domínguez, B.; Finocchiaro, P.; Fiore, S.; Furman, V.; García-Infantes, F.; Gervino, G.; Gilardoni, S.; Guerrero, C.; Gunsing, F.; Gustavino, C.; Hillman, W.; Jenkins, D.; Jericha, E.; Junghans, A.; Kadi, Y.; Kaperoni, K.; Kaur, G.; Kimura, A.; Knapová, I.; Kokkoris, M.; Kopatch, Y.; Krtička, M.; Kyritsis, N.; Ladarescu, I.; Lederer-Woods, C.; Lerendegui-Marco, J.; Lerner, G.; Manna, A.; Masi, A.; Massimi, C.; Mastinu, P.; Mastromarco, M.; Maugeri, E.-A.; Mazzone, A.; Mengoni, A.; Michalopoulou, V.; Milazzo, P.; Mucciola, R.; Murtas, F.; Musacchio-Gonzalez, E.; Musumarra, A.; Negret, A.; Pérez-Maroto, P.; Patronis, N.; Pavón-Rodríguez, J.-A.; Pellegriti, M.; Petrone, C.; Pirovano, E.; Plaza del Olmo, J.; Pomp, S.; Porras, I.; Praena, J.; Quesada, J.-M.; Reifarth, R.; Rochman, D.; Romanets, Y.; Rubbia, C.; Sabaté-Gilarte, M.; Schumann, D.; Sekhar, A.; Smith, G.; Sosnin, N.; Stamati, M.-E.; Sturniolo, A.; Tagliente, G.; Tarifeño-Saldivia, A.; Tarrío, D.; Torres-Sánchez, P.; Vagena, V.; Valenta, S.; Variale, V.; Vaz, P.; Vecchio, G.; Vescovi, D.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Woods, P.-J.; Wright, T.; Zarrella, R.; Žugec, P.

Abstract

The experimental setup of the new measurement of 239Pu fission and capture cross-section in the n_TOF time-of-flight facility at CERN is presented. The measurement aims to address the needs and demands of nuclear data users. The experiment incorporates an innovative fast Fission Fragment Detector and the n_TOF Total Absorption Calorimeter, enabling the implementation of the fission tagging technique. Preliminary results exhibit the robust performance of the detector systems, along with the high quality of the new 239Pu samples. These samples were exclusively produced for this measurement by the European Commission’s Joint Research Centre in Geel.

Keywords: CERN n_ToF; 239Pu; neutron induced fission; neutron capture

Permalink: https://www.hzdr.de/publications/Publ-40894


Description and outlook of the 50, 53Cr(n, γ) cross section measurement at n_TOF and HiSPANoS

Pérez-Maroto, P.; Guerrero, C.; Casanovas, A.; Fernández, B.; Aberle, O.; Alcayne, V.; Altieri, S.; Amaducci, S.; Andrzejewski, J.; Babiano-Suarez, V.; Bacak, M.; Balibrea Correa, J.; Beltrami, C.; Bennett, S.; Bernardes, A. P.; Berthoumieux, E.; Beyer, R.; Boromiza, M.; Bosnar, D.; Caamaño, M.; Calviño, F.; Calviani, M.; Cano-Ott, D.; Castelluccio, D. M.; Cerutti, F.; Cescutti, G.; Chasapoglou, S.; Chiaveri, E.; Colombetti, P.; Colonna, N.; Console Camprini, P.; Cortés, G.; Cortés-Giraldo, M. A.; Cosentino, L.; Cristallo, S.; Dellmann, S.; Di Castro, M.; Di Maria, S.; Diakaki, M.; Dietz, M.; Domingo-Pardo, C.; Dressler, R.; Dupont, E.; Durán, I.; Eleme, Z.; Fargier, S.; Fernández-Domínguez, B.; Finocchiaro, P.; Fiore, S.; Furman, V.; García-Infantes, F.; Gawlik-Ramięga, A.; Gervino, G.; Gilardoni, S.; González-Romero, E.; Gunsing, F.; Gustavino, C.; Heyse, J.; Hillman, W.; Jenkins, D. G.; Jericha, E.; Junghans, A.; Kadi, Y.; Kaperoni, K.; Kaur, G.; Kimura, A.; Knapová, I.; Kokkoris, M.; Kopatch, Y.; Krtička, M.; Kyritsis, N.; Ladarescu, I.; Lederer-Woods, C.; Lerendegui-Marco, J.; Lerner, G.; Manna, A.; Martínez, T.; Masi, A.; Massimi, C.; Mastinu, P.; Mastromarco, M.; Maugeri, E. A.; Mazzone, A.; Mendoza, E.; Mengoni, A.; Michalopoulou, V.; Milazzo, P. M.; Mucciola, R.; Murtas, F.; Musacchio-Gonzalez, E.; Musumarra, A.; Negret, A.; Pérez de Rada, A.; Patronis, N.; Pavón-Rodríguez, J. A.; Pellegriti, M. G.; Perkowski, J.; Petrone, C.; Pirovano, E.; Plaza del Olmo, J.; Pomp, S.; Porras, I.; Praena, J.; Quesada, J. M.; Reifarth, R.; Rochman, D.; Romanets, Y.; Rubbia, C.; Sánchez-Caballero, A.; Sabaté-Gilarte, M.; Schillebeeckx, P.; Schumann, D.; Sekhar, A.; Smith, A. G.; Sosnin, N. V.; Stamati, M. E.; Sturniolo, A.; Tagliente, G.; Tarifeño-Saldivia, A.; Tarrío, D.; Torres-Sánchez, P.; Vagena, E.; Valenta, S.; Variale, V.; Vaz, P.; Vecchio, G.; Vescovi, D.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Woods, P. J.; Wright, T.; Zarrella, R.; Žugec, P.

Abstract

Chromium is a very relevant element regarding criticality safety in nuclear reactors because of its presence in stainless steel, an important structural material. Currently, there are serious discrepancies between the different evaluations regarding the neutron capture cross sections of 50Cr and 53Cr, most probably related to the difficulty of reducing and then estimating the very large neutron scattering effects on the shape of the resonances. In this context, there is a recent entry in the Nuclear Energy Agency (NEA) High Priority Request List (HPRL) to measure these reactions between 1 and 100 keV with an accuracy of 8-10%. In response to this request, we have performed a time-of-flight experiment at CERN n_TOF (Switzerland) and a complementary activation experiment on 50Cr at 30 and 90 keV at CNA HiSPANoS (Spain). The experiments are presented herein, together with a discussion on the quality of the preliminary data and the results to be expected.

Keywords: CERN n_ToF; HiSPANoS; neutron capture

Permalink: https://www.hzdr.de/publications/Publ-40893


Combining Liposomal Photocatalysts with Whole-Cell Catalysts for One-pot Photobiocatalysis

Zhang, J.; Batista, V. F.; Hübner, R.; Vogel, S.; Wu, C.

Abstract

Cooperative photobiocatalytic processes have seen extensive potentials for the synthesis of both bulk and fine chemicals owing to their versatility, eco-friendliness, and cost-effectiveness. Nevertheless, developing a universal and effective synthetic strategy compatible with both catalytic systems remains challenging. In this study, we explored cationic liposomes as biocompatible photocatalyst encapsulation systems and combined them with bacteria overexpressing enzymes for two-step and three-step cascade reactions. Specifically, the water-soluble photocatalyst anthraquinone-2-sulfonate (AQS), which can oxidize benzyl alcohol, is encapsulated within the core of cationic liposomes composed of dioleoyl-3-trimethylammonium propane (DOTAP) and the helper lipid cholesterol. The positive charge on the liposome surface enabled electrostatic interactions with the negative charges on the membrane of Escherichia coli cells. Bacterial cells overexpressing various enzymes, such as Candida antarctica lipase B (CalB) and benzaldehyde lyase (BAL), and coated with liposomes enabled the production of added value compounds through cascade reactions with excellent production. These cascades involve CalB-catalyzed hydrolysis, BAL-catalyzed condensation, and AQS-driven photo-oxidation reactions. Therefore, the strategy offers more possibilities of combining photocatalysis with biocatalysis for recoverability, enhanced mass transfer, and enhanced compatibility in both industrial biotechnology and synthetic chemistry.

Involved research facilities

Related publications

Permalink: https://www.hzdr.de/publications/Publ-40892


Data publication: Noise-induced nonreciprocal topological dissipative solitons in directionally coupled chains and lattices

Pinto Ramos, D. I.; Alfaro-Bittner, K.; Rojas, R. G.; Clerc, M. G.

Abstract

Simulation data in .npy format (Python) and the corresponding scripts (.py files) to run and generate the plots in the article.

Related publications

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40891


n_TOF Detector Developments

Patronis, N.; Aberle, O.; Alcayne, V.; Alpar, G.; Al Halabi, M.; Amaducci, S.; Babiano, V.; Bacak, M.; Balibrea-Correa, J.; Bartolomé, J.; Bernardes, A.-P.; Gameiro, B. B.; Berthoumieux, E.; Beyer, R.; Birch, M.; Boromiza, M.; Bosnar, D.; Brusasco, B.; Caamaño, M.; Cahuzac, A.; Calviño, F.; Calviani, M.; Cano-Ott, D.; Casanovas, A.; Castelluccio, D.; Catlett, D.; Cerutti, F.; Cescutti, G.; Chiaveri, E.; Claps, G.; Colombetti, P.; Colonna, N.; Console Camprini, P.; Cortés, G.; Cortés-Giraldo, M.; Cosentino, L.; Cristallo, S.; D'Ottavi, A.; de la Fuente Rosales, G.; Dellmann, S.; Diakaki, M.; Di Castro, M.; Di Chicco, A.; Dietz, M.; Domingo-Pardo, C.; Dupont, E.; Durán, I.; Eleme, Z.; Eslami, M.; Fargier, S.; Fernández-Domínguez, B.; Finocchiaro, P.; Flanagan, W.; Furman, V.; Gandhi, A.; García-Infantes, F.; Gawlik-Ramięga, A.; Gervino, G.; Gilardoni, S.; González-Romero, E.; Goula, S.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Gustavino, C.; Heyse, J.; Hillman, W.; Jenkins, D.; Jericha, E.; Junghans, A.; Kadi, Y.; Kaperoni, K.; Kelly, I.; Kokkoris, M.; Kopatch, Y.; Krtička, M.; Kyritsis, N.; Lederer-Woods, C.; Lerendegui-Marco, J.; Manna, A.; Martínez, T.; Martínez-Cañada, M.; Masi, A.; Massimi, C.; Mastinu, P.; Mastromarco, M.; Maugeri, E.-A.; Mazzone, A.; Mendoza, E.; Mengoni, A.; Michalopoulou, V.; Milazzo, P.; Moldenhauer, J.; Mucciola, R.; Musacchio González, E.; Musumarra, A.; Negret, A.; Odusina, E.; Papanikolaou, D.; Pavón-Rodríguez, J.; Pellegriti, M.; Pérez-Maroto, P.; Pérez de Rada Fiol, A.; Perfetto, G.; Perkowski, J.; Petrone, C.; Pieretti, N.; Piersanti, L.; Pirovano, E.; Porras, I.; Praena, J.; Quesada, J.-M.; Reifarth, R.; Rochman, D.; Romanets, Y.; Rooney, A.; Rovira, G.; Rubbia, C.; Sánchez-Caballero, A.; Sahoo, S.; Scarpa, D.; Schillebeeckx, P.; Smith, G.; Sosnin, N.; Spelta, M.; Stamati, M.-E.; Stasiak, K.; Tagliente, G.; Tarifeño-Saldivia, A.; Tarrío, D.; Torres-Sánchez, P.; Tosi, S.; Tsiledakis, G.; Valenta, S.; Vaz, P.; Vecchio, G.; Vescovi, D.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Weiss, C.; Woods, P. J.; Wright, T.; Wu, R.; Žugec, P.

Abstract

In this report, the ongoing developments of the n_TOF detectors are presented. The document describes the capabilities related to new research avenues and perspectives in new physics research with the n_TOF collaboration. It specifically summarizes the long and ongoing efforts of different working groups in developing detectors, considering the specific characteristics of the n_TOF experimental areas, with the goal of fully leveraging the unique features of the n_TOF facility.

Keywords: detector development; neutron physics; nuclear astrophysics; neutron induced fission studies; neutron induced charged particle reactions; CERN n_TOF; Time Of Flight; nuclear physics; medical physics; nuclear physics applications

Involved research facilities

Related publications

  • Open Access Logo Contribution to external collection
    in: CERN-n_TOF-PUB-2024-001, Geneva, Switzerland: CERN, 2024

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40887


Magnetocaloric effect in La1−zCez(Fe0.88−yMnySi0.12)13 with tunable, low transition temperature in high magnetic fields

Straßheim, M.; Salazar Mejia, C.; Bykov, E.; Niehoff, T.; Beyer, L.; Freudenberger, J.; Hübner, R.; Ganss, F.; Naumann, T.; Wosnitza, J.; Gottschall, T.

Abstract

Cryogenic magnetic refrigeration becomes more and more important nowadays, especially for the liquefaction of gases such as hydrogen. In this study, we have synthesized La1–zCez(Fe0.88–yMnySi0.12)13 samples and investigated their magnetic and magnetocaloric properties in order to assess their potential for cryogenic applications. By adjusting the Mn and Ce content and adding excess rare-earth elements, the first-order ferromagnetic transition was lowered from 200 to 40 K and the adiabatic temperature change of the samples was measured directly using pulsed magnetic fields. The sample with the lowest transition temperature still showed a significant adiabatic temperature change in magnetic fields up to 10 T, with an increasingly stronger first-order transition observed in samples with higher Ce substitution. In addition, we synthesized spherical powder with diameters between 20 and 120 μm using ultrasonic atomization while maintaining the magnetic transition, which is a promising starting material for future additive manufacturing of magnetocaloric materials.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

Downloads

  • Secondary publication expected from 29.01.2026

Permalink: https://www.hzdr.de/publications/Publ-40886


Challenges and Future Directions of ART

Richter, C.; Jäckel, O.; Weykamp, F.; Dankulchai, P.

Abstract

Panel discussion

Involved research facilities

  • OncoRay
  • Lecture (others)
    PSCM School in Adaptive Radiation Therapy 2024, 12.-14.12.2024, Bangkok, Thailand

Permalink: https://www.hzdr.de/publications/Publ-40885


ART with particle therapy

Richter, C.

Abstract

ART with particle therapy

Involved research facilities

  • OncoRay
  • Invited lecture (Conferences)
    PSCM School in Adaptive Radiation Therapy 2024, 12.-14.12.2024, Bangkok, Thailand

Permalink: https://www.hzdr.de/publications/Publ-40884


Low-energy spin excitations in field-induced phases of the spin-ladder antiferromagnet BiCu2PO6

Pilch, P.; Amelin, K.; Schmiedinghoff, G.; Reinold, A.; Zhu, C.; Povarov, K.; Zvyagin, S.; Engelkamp, H.; Lan, Y.-P.; Shu, G.-J.; Chou, F. C.; Nagel, U.; Room, T.; Uhrig, G. S.; Fauseweh, B.; Wang, Z.

Abstract

We report on terahertz spectroscopic measurements of quantum spin dynamics on single crystals of a spin-1/2 frustrated spin-ladder antiferromagnet BiCu2PO6 as a function of temperature, polarization, and applied external magnetic fields. Spin triplon excitations are observed at zero field and split in applied magnetic fields. For magnetic fields applied along the crystallographic a axis, a quantum phase transition at Bc1 = 21.4 T is featured by a low-energy excitation mode emerging above Bc1, which indicates a gap reopening. For fields along the b axis and the c axis, different field dependencies are observed for the spin triplon excitations, whereas no low-lying modes could be resolved at field-induced phase transitions. We perform a theoretical analysis of the magnetic field dependence of the spin triplon modes by using continuous unitary transformations to determine an effective low-energy Hamiltonian. Through an exhaustive parameter search we find numerically optimized parameters to very well describe the experimentally observed modes, which corroborate the importance of significant magnetic anisotropy in the system.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

Permalink: https://www.hzdr.de/publications/Publ-40883


High precision image-guided proton therapy in 10 years

Richter, C.

Abstract

High precision image-guided proton therapy in 10 years

Involved research facilities

  • OncoRay
  • Invited lecture (Conferences)
    Advanced Imgaing in Radiotherapy, 29.-31.01.2024, Brussels, Belgium

Permalink: https://www.hzdr.de/publications/Publ-40882


Data publication: Exchange-Biased Multiring Planar Hall Magnetoresistive Sensors With Nanotesla Resolution in Nonshielded Environments

Schmidtpeter, J.; Das, P. T.; Zabila, Y.; Schubert, C.; Gundrum, T.; Wondrak, T.; Makarov, D.

Abstract

This entry includes the data presented in the publication "Exchange-Biased Multiring Planar Hall Magnetoresistive Sensors With Nanotesla Resolution in Nonshielded Environments"

Keywords: Magnetic Sensors; Planar Hall Effect; Noise Spectral Density

Related publications

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40881


Status and Application Perspectives of Laser Plasma Accelerators - the role of beam transport

Schramm, U.

Abstract

HED Invited Conference Talk / Introduction to plasma accelerators

Keywords: Plasma accelerators

Involved research facilities

Related publications

  • Invited lecture (Conferences)
    45th International Workshop on High-Energy-Density Physics with Intense Ion and Laser Beams, 27.-30.01.2025, Hirschegg, Österreich

Permalink: https://www.hzdr.de/publications/Publ-40877


Advancement of High Intensity Laser Driven Particle Accelerators to Application Readiness

Schramm, U.

Abstract

Eingeladener Vortrag zur Laser Ionenbeschleunigung und Anwendungen

Keywords: Laser proton acceleration; Plasma accelerator

Involved research facilities

  • Draco
  • Invited lecture (Conferences)
    44th International Workshop on High-Energy-Density Physics with Intense Ion and Laser Beams, 29.01.-01.02.2024, Hirschegg, Österreich
  • Invited lecture (Conferences)
    OPTICA High Brightness Sources and Ligth-Driven Interactions Congress High Intensity Lasers and High Field Phenomena, 12.-14.03.2024, Wien, Österreich
  • Invited lecture (Conferences)
    ICUIL Preisträgervortrag, 09.-13.09.2024, Cozumel, Mexico
  • Invited lecture (Conferences)
    ASILS 13, 16.-18.12.2024, Labh Garh Palace, Udaipur, Rajasthan, Indien

Permalink: https://www.hzdr.de/publications/Publ-40875


Integration of imaging in clinical protocols of particle therapy

Trnkova, P.; Bolsi, A.; Knopf, A.; Hoffmann, A. L.

Abstract

An examination of the current landscape of image guidance in particle therapy, as utilized across numerous European particle therapy centres, will be provided herein. This analysis will encompass considerations pertaining to the anatomical location of tumours, the diverse clinical experiences, and the specific clinical demands encountered by various particle therapy centres.

  • Book chapter
    in: Imaging in Particle Therapy Current practice and future trends, London: IOP Publishing Ltd, 2024, 13-1-13-16
    DOI: 10.1088/978-0-7503-5117-1ch13

Permalink: https://www.hzdr.de/publications/Publ-40872


Explorando os efeitos magnetocalóricos em materiais com transições de primeira ordem: um foco em altos campos magnéticos e baixas temperaturas

Salazar Mejia, C.

Abstract

es hat keine aussagefähiges Abstract vorgelegen

Involved research facilities

  • High Magnetic Field Laboratory (HLD)
  • Invited lecture (Conferences) (Online presentation)
    Workshop on i-Caloric Effects 2024, 25.-27.03.2024, Rio de Janeiro, Brasilien

Permalink: https://www.hzdr.de/publications/Publ-40870


Wissenschaftliche Metadaten und ihre Potenziale freilegen: Maßgeschneiderte Metadaten-Schulung für den Forschungsbereich Matter

Özkan, Ö.; Schaller, T.; Haghiri, H.; Günther, G.; Kubin, M.; Mannix, O.

Abstract

Um Forschende in den Grundkenntnissen der Metadatenkuration zu schulen, hat HMC den
Trainingskurs “Fundamentals of Scientific Metadata” entwickelt. (Gerlich et al. 2023)
HMC Hub Matter hat diesen Trainingskurs kürzlich für Communities aus dem Forschungsbereich
Materie angepasst, die von Teilchen-, Ionenstrahl- und Beschleunigerphysik bis hin zu Photonen- und
Neutronenforschung an Großgeräten reicht.

Keywords: Metadata Training; Fundamentals Training; HMC

  • Poster
    5. SaxFDM Tagung, 17.09.2024, Freiberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40869


Advancing Al-doped ZnO thin films structural, optical and electrical properties of low temperature PET substrates via flash lamp annealing

Lee, J.; Jo, C.-H.; Lee, G.; Bae, M.-S.; Prucnal, S.; Zhou, S.; Zubair Khan, M.; Gohar, O.; Saleem, M.; Koh, J.-H.

Abstract

In this study, aluminum-doped zinc oxide (AZO) thin films were deposited onto a low-temperature polyethylene terephthalate (PET) substrate using DC magnetron sputtering. Deposition parameters included power range of 100−300 W, a working pressure of 15 mTorr, and a substrate temperature of 50 °C. Post-deposition, flash lamp annealing (FLA) was employed as a rapid thermal processing method with a pulse duration of 1.7 ms and energy density of 7 J·cm−2, aimed at enhancing the film's quality while preserving the temperature-sensitive PET substrate. FLA offers advantages over conventional annealing,
including shorter processing times and improved material properties. The structural, optical, and electrical characteristics of the AZO films were assessed using X-ray diffraction, field emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, ultraviolet−visible spectroscopy, and Hall effect measurements. The results demonstrated that properties of AZO films varied with deposition and annealing conditions. Films deposited at 200 W and subjected to FLA exhibited superior crystallinity, with average visible light transmittance exceeding 80% and resistivity as low as 0.38 Ω·cm representing 95% improvement in transmittance. Electrical analysis revealed that carrier concentration, mobility, and resistivity were influenced by both sputtering and annealing parameters. These findings underscore the effectiveness of FLA in optimizing AZO thin film properties, highlighting potential in optoelectronics applications.

Keywords: Flash Lamp Annealing; AZO; sputtering; flexible electronics; doping

Involved research facilities

Related publications

Downloads

  • Secondary publication expected from 15.09.2025

Permalink: https://www.hzdr.de/publications/Publ-40868


Defect migration and phase transformations in two-dimensional iron chloride inside bilayer graphene

Liu, Q.; Sun, H.; Lin, Y.-C.; Ghorbani Asl, M.; Kretschmer, S.; Solís-Fernández, P.; Siao, M.-D.; Chiu, P.-W.; Ago, H.; Krasheninnikov, A.; Suenaga, K.

Abstract

The intercalation of metal chlorides, and particularly iron chlorides, into graphitic carbon structures has recently received lots of attention, as it can not only protect this two-dimensional (2D) magnetic system from the effects of the environment, but also substantially alter the magnetic, electronic, and optical properties of both intercalant and host material. At the same time, the intercalation can result in the formation of structural defects, or defects can appear under external stimuli, which can affect materials performance. These aspects have received so far little attention in the dedicated experiments. In this study, we investigate the behavior of atomic-scale defects in iron chlorides intercalated into bilayer graphene (BLG) by using scanning transmission electron microscopy (STEM) and first-principles calculations. We observe transformations between the FeCl2 and FeCl3 phases and elucidate the role of defects in the transformations. Specifically, three types of defects are identified: Fe vacancies in FeCl2 domains, Fe adatoms and interstitials in FeCl3 domains, each exhibiting distinct dynamic behaviors. Our findings not only advance the understanding of intercalation chemistry of 2D materials, but also highlight the profound impact of atomic-scale defects on their properties and potential technological applications.

Keywords: intercalation; STEM; iron chloride; phase transformation; bilayer graphene

Involved research facilities

Related publications

Downloads

  • Secondary publication expected from 24.01.2026

Permalink: https://www.hzdr.de/publications/Publ-40867


The VECTOR project - Overview and current status

Pereira, T.; Stockey, C.

Abstract

The presentation prepared for the PDAC 2024, is a short summary about the VECTOR project and its current status.

Keywords: VECTOR; Exploration; Shared Value; Data Science; Geoscience; Social Science

  • Open Access Logo Invited lecture (Conferences)
    PDAC 2024, 03.-6.3.2024, Toronto, Canada

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40866


On the characterization of battery materials by means of iGC

Sygusch, J.; Rudolph, M.

Abstract

Characterization of Lithium ion battery components using inverse gas chromatography

  • Invited lecture (Conferences)
    Sorption Symposium Europe 2024 ​, 18.-19.09.2024, Wien, Österreich

Permalink: https://www.hzdr.de/publications/Publ-40865


Gorno and Piani Resinelli: genesis and correlations of two Alpine-type Pb-Zn districts

Summino, L.; Giorno, M. A.; Barale, L.; Bertok, C.; Frenzel, M.; Gasparrini, M.; Martire, L.

Abstract

The strata-bound, carbonate-hosted Pb-Zn-Ag (+ fluorite + baryte) districts of Gorno and Piani Resinelli belong to the Alpine metallogenic province located between Italy, Austria and Slovenia. The orebodies are hosted in the lower Carnian stratigraphic succession of the Lombardian Basin (Southalpine Domain, N Italy), mainly composed of peritidal limestones. The aim of this study is to constrain the ore-forming conditions using petrography, geochemistry, fluid inclusion microthermometry, and radiometric datings on both ore minerals
and associated diagenetic products.

Petrographic studies reveal that the mineralization was preceded by dolomitization, silicification, and brecciation events. Thermometric data from primary fluid inclusions in dolomite, sphalerite, and fluorite indicate the involvement of moderately hot (T between 70 and 150 °C) and high-salinity fluids (up to ~20 wt % eq NaCl) during ore precipitation. Radiometric dating performed on associated diagenetic minerals which pre- and postdate the sulfide mineralization reveals that the precipitation of the ore minerals occurred during the LateTriassic. Moreover, in situ analyses (EPMA, LA-ICP-MS) of trace elements on sphalerite will be presented here, including their implications for ore-forming conditions.

Several similarities between Gorno and Piani Resinelli in terms of diagenetic evolution of the host rock, temperature and composition of the fluids, and timing of the ore precipitation highlight the possibility that both districts could be related to a unique, widespread Late Triassic hydrothermal system, in which metal-rich fluids flowed upward through faults and associated fractures. This circulation in the Upper Triassic stratigraphic succession caused major modifications in the host rocks such as multiphase dolomitization, silicification,
dissolution, and brecciation, as well as the precipitation of ore minerals in a shallow burial setting.

  • Lecture (Conference)
    SGI - SIMP 2024 - Geology for a sustainable management of our Planet, 03.-05.09.2024, Bari, Italy

Permalink: https://www.hzdr.de/publications/Publ-40864


Piani Resinelli district: preliminary data on ore precipitation and multiphase diagenetic evolution

Summino, L.; Giorno, M. A.; Barale, L.; Bertok, C.; Frenzel, M.; Gasparrini, M.; Martire, L.

Abstract

The strata-bound, carbonate-hosted Pb-Zn-Ag deposit of Piani Resinelli belongs to the Alpine metallogenic province. The mineralization is hosted in the lower Carnian stratigraphic succession of the Lombardian Basin (Southalpine Domain, North Italy). The origin of the deposit is still unknown as previous studies are largely outdated. This study aims to constrain the ore-forming conditions using petrographic, geochemical and fluid inclusion studies on both ore minerals and associated diagenetic cements.The mineralization was preceded by dolomitization, silicification, dissolution and brecciation events. Preliminary thermometric data on fluid inclusions indicate the involvement of moderately hot temperature (between 115 and 150 °C), high-salinity brines (up to ~20 wt eq% NaCl) in ore genesis. In situ analyses (EPMA, LA-ICP-MS) of trace elements in sphalerite are in progress and will be presented with their
implications on ore-forming conditions. The origin of the Resinelli district was probably linked to an Upper Triassic hydrothermal system, in which metal-rich fluids flowed upward along faults and associated fractures. This circulation in the Upper Triassic succession caused major mineralogical and textural modifications in the host rocks and the precipitation of ore minerals in a shallow burial setting. The host rock diagenetic evolution and the types of hydrothermal fluids involved in ore precipitation share similarities with the nearby Gorno district, suggesting that the two deposits could have formed during the same regional mineralizing event.

  • Poster
    IAEG 50 - 50 Years of Irish-type Zn-Pb Deposits, 08.-10.09.2023, Galway, Ireland

Permalink: https://www.hzdr.de/publications/Publ-40863


Piani Resinelli District: Preliminary Data on Ore Precipitation and Multiphase Diagenetic Evolution

Summino, L.; Giorno, M. A.; Barale, L.; Bertok, C.; Frenzel, M.; Gasparrini, M.; Martire, L.

Abstract

The stratabound, carbonate-hosted Pb-Zn-Ag (± fluorite ± baryte) deposit of Piani Resinelli belongs to the Alpine metallogenic province located between Italy, Austria, and Slovenia. The mineralization is hosted in the Lower Carnian stratigraphic succession of the Lombardian basin (Southalpine Domain, north Italy), mainly composed of peritidal limestones. The origin of the deposit is still unknown since the previous studies are largely outdated. The aim of this study is to constrain the ore-forming conditions using petrographic, geochemical, and fluid inclusion studies on both ore minerals and associated diagenetic cements.
Preliminary results show that the mineralization was preceded by dolomitization, silicification, and brecciation events. The occurrence of saddle dolomite locally associated with micritic sediments in geopetal structures points to a shallow burial and thus a hydrothermal origin of dolomite.
Preliminary thermometric data on fluid inclusions indicate the involvement of moderately hot temperatures (between 115° and 150°C), high-salinity brines (up to ~20 eq wt % NaCl) in ore genesis. Moreover, in situ analyses (EPMA, LA-ICP-MS) of trace elements on sphalerite are presently in progress and will be presented here, including their implications for ore-forming conditions.
The origin of the Resinelli district was probably linked to an Upper Triassic hydrothermal system, in which metal-rich fluids flowed upward, possibly through faults and associated fractures. This circulation in the Upper Triassic succession caused major modifications in the host rocks such as multiphase dolomitization, silicification, and brecciation, as well as the precipitation of ore minerals in a shallow burial setting. The results of this preliminary characterization show several similarities between the Piani Resinelli and the nearby Gorno districts in terms of the diagenetic evolution of the host rocks, temperature and composition of the hydrothermal fluids, and timing of the fluids involved in ore precipitation, suggesting that both districts could have formed during the same regional mineralization event.

  • Poster
    SEG 2023 Conference: Resourcing the Green Transition, 26.-29.08.2023, London, UK

Permalink: https://www.hzdr.de/publications/Publ-40862


In-situ moisture measuring in concrete structures of containment buildings during decommissioning of nuclear power plants

Nurjahan, T.; de Assis Dias, F.; Schleicher, E.; Hampel, U.

Abstract

Moisture measuring in concrete structures of containment buildings during decommissioning of nuclear power plants

Involved research facilities

  • TOPFLOW Facility
  • Poster
    Nuclear Day 2024, 12.-13.09.2024, Pilsen, Czech Republic

Permalink: https://www.hzdr.de/publications/Publ-40860


In-situ measurement of moisture content and contamination in concrete during decommissioning of nuclear power plants

Nurjahan, T.; de Assis Dias, F.; Schleicher, E.; Hampel, U.

Abstract

In-situ moisture measurement in concrete during decommissioning of nuclear power plants

Involved research facilities

  • TOPFLOW Facility
  • Lecture (Conference)
    Kerntech 2023, 13.-15.06.2023, Frankfurt, Germany

Permalink: https://www.hzdr.de/publications/Publ-40859


short course: Short introduction to using the HIF ELN

Schaller, T.

Abstract

Have you ever tried to make sense of your collaborators’ notes or even your own after 5 years? Did you ever have trouble finding the exact information about the processing and analyses of your sample, especially at short notice?
As researchers we know, that keeping track of all the steps in our scientific work including processing, analysis, evaluation and so on is essential. We aim at documenting our work in a way that others - including our future self - can make sense of it. But often we lack the time and sometimes also the knowledge to do it properly. Thus, too often, we end up publishing results in a way that doesn’t (completely) comply with modern requirements of sustainable research publication.
The newly developed Electroning Lab Notebook (ELN) for the HIF was implemented to help you with the organisation of your samples. You can use it to register samples and connect all the information you like with the registered samples. Further on you can use it to file prepartion requests electronically and thus provide all the necessary information to the preparation lab in a much shorter time.
In this short course we will discuss the necessity for the electronic documentation of your work. Also we will show you how to register samples in the ELN and start preparation requests.
The course will run for two ours with roughly one hour of theory and one hour of hands-on training. There will be a limited number of seats for in-person participation. More people can join online.

Keywords: Metadata Training; Fundamentals Training; Electronic Lab Notebook (ELN)

  • Open Access Logo Lecture (others)
    Training Course, 18.11.2024, Freiberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40857


Fundamentals of Scientific Metadata - Why context matters - Helmholtz Summer School 2025

Gerlich, S.; Schaller, T.; Haghiri, H.

Abstract

This course is an entry-level introduction to the fundamentals of scientific metadata for PhD students, early-career researchers, and postdocs. In this course we will look at the intricate relationship between (digital) research data, metadata, and knowledge; discuss why metadata is critical in today’s research; and explain some of the technologies and concepts related to structured machine-readable metadata.

Have you ever struggled to make sense of scientific data provided by a collaborator? Or, even worse, to understand your own data five months after publication... Do you have difficulties in meeting the data description requirements of your funding agency? Do you want your data to have lasting value; but don’t know how to ensure that?
Precise and structured descriptions of research data are key for scientific exchange and progress - and for ensuring recognition of your effort in data collection. The solution: make your data findable, accessible, interoperable, and reusable - by describing them with metadata.

This course is targeted especially at scientific staff and researchers in the Helmholtz Research Field Information but is open to anyone who would like to better understand research data annotation with metadata.

You will learn:

  • about the differences between, and the importance of data & metadata
  • how to annotate your research data with structured metadata
  • how to find and evaluate a suitable metadata framework and data repository
  • how to use basic Markdown / JSON / XML
  • which tools are already available to level up your metadata annotation game
  • why structured metadata is important and how it can increase your scientific visibility

Keywords: Metadata Training; Fundamentals Training; HMC

  • Open Access Logo Lecture (others) (Online presentation)
    Helmholtz Summer School, 16.-27.09.2024, online, online

Permalink: https://www.hzdr.de/publications/Publ-40856


Fundamentals of Scientific Metadata - Why context matters

Gerlich, S.; Schaller, T.

Abstract

This course is an entry-level introduction to the fundamentals of scientific metadata for PhD students, early-career researchers and Postdocs. In this course we will look at the intricate relationship between (digital) research data, metadata and knowledge, discuss why metadata is critical in today’s research, as well as explain some of the technologies and concepts related to structured machine-readable metadata.

Have you ever struggled to make sense of scientific data provided by a collaborator - or even understanding your own data 5 months after publication? Do you see difficulties in meeting the data description requirements of your funding agency? Do you want your data to have lasting value, but don’t know how to ensure that?

Precise and structured description of research data is key for scientific exchange and progress - and also for the recognition of your effort in data collection. The solution: make your data findable, accessible, interoperable and reusable by describing them with metadata.

This course is targeted especially at scientific staff and researchers in the Helmholtz Research Field Information but is open to anyone, who would like to better understand research data annotation with metadata.

You will learn:

  • about the differences between and the importance of data & metadata
  • to annotate your research data with structured metadata
  • to find and evaluate a suitable metadata framework and data repository
  • to use basic Markdown / JSON / XML
  • which tools are already available to level up your metadata annotation game
  • why structured metadata is important and how it can increase your scientific visibility

Keywords: Metadata Training; Fundamentals Training; HMC

  • Open Access Logo Lecture (others) (Online presentation)
    Training Course, 22.-23.02.2024, online, online

Permalink: https://www.hzdr.de/publications/Publ-40855


Magnetic resonance imaging in particle therapy

Paganelli, C.; Oborn, B.; Hoffmann, A. L.; Riboldi, M.

Abstract

Magnetic resonance imaging (MRI) has recently become successful in radiation oncology thanks to its exquisite soft tissue contrast and radiation free properties. This image modality can be therefore excellent also in a particle therapy (PT) workflow. In this chapter, we will overview the current and potential use of MRI in PT in treatment planning and delivery, with a dedicated section on the novel technology integrating MRI with proton therapy units.

  • Book chapter
    in: Imaging in Particle Therapy Current practice and future trends, London: IOP Publishing Ltd, 2024, 7-1-7-21
    DOI: 10.1088/978-0-7503-5117-1ch7

Permalink: https://www.hzdr.de/publications/Publ-40854


DNA language model GROVER learns sequence context in the human genome

Sanabria, M.; Hirsch, J.; Joubert, P.; Poetsch, A. R.

Abstract

Deep-learning models that learn a sense of language on DNA have achieved a high level of performance on genome biological tasks. Genome sequences follow rules similar to natural language but are distinct in the absence of a concept of words. We established byte-pair encoding on the human genome and trained a foundation language model called GROVER (Genome Rules Obtained Via Extracted Representations) with the vocabulary selected via a custom task, next-k-mer prediction. The defined dictionary of tokens in the human genome carries best the information content for GROVER. Analysing learned representations, we observed that trained token embeddings primarily encode information related to frequency, sequence content and length. Some tokens are primarily localized in repeats, whereas the majority widely distribute over the genome. GROVER also learns context and lexical ambiguity. Average trained embeddings of genomic regions relate to functional genomics annotation and thus indicate learning of these structures purely from the contextual relationships of tokens. This highlights the extent of information content encoded by the sequence that can be grasped by GROVER. On fine-tuning tasks addressing genome biology with questions of genome element identification and protein–DNA binding, GROVER exceeds other models’ performance. GROVER learns sequence context, a sense for structure and language rules. Extracting this knowledge can be used to compose a grammar book for the code of life.

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40853


Anisotropic Resonant Scattering at the uranium M4 edge: Insights into U2N3

Lawrence Bright, E. S.; Harding, L. M.; Porter, D. G.; Springell, R.; Lander, G. H.

Abstract

The observation of anisotropic resonant x-ray scattering (ARS) opens new perspectives for describing the bonding in actinide materials. The method relies on intensity appearing at the resonant energy at Bragg reflections that are either forbidden or very weak. One can think of these reflections as arising from an almost exact cancellation of the spherical components of the charge densities (principally arising from the electrons in the radon core), so that the remaining aspherical contributions are observed. We have detected such intensity at the U M4-edge in semi-metallic U2N3 epitaxial films [1].

ARS (also called Anisotropic Tensor of Susceptibility) has been practiced for many years in the case of the K-edge of transition metal systems [2]. However, the K edge has both dipole 2s→4p (E1), as well as quadrupolar 2s→3d (E2) channels, with ~equal strength. L-edges are more restrictive, but have low energies making diffraction experiments difficult. In certain cases, 2p-3d hybridization or orbital ordering may be clearly identified [2,3]. In the 5f series the situation is different, the M-edge E1 (3d→5f) transition is strong, with E2 (3d→6g or 7s) being very weak, meaning that the transition to states which contribute to the bonding dominates. Additionally, the wavelength of 3.3 Å allows a number of Bragg reflections to be accessed. These unique properties give ARS a promising place for the study of bonding in 5f systems.

We will present the results of ARS measurements on a 200 nm single crystal U2N¬3 film using the I16 beamline at Diamond Light Source. U2N3 has a bcc bixbyite structure (Space group #206). There are two types of uranium in the unit cell: U1 sits at 8b position, with coordinates (¼,¼,¼) which is an inversion center and the second uranium, U2, sits at position 24d with coordinates (x,0,¼) where x ~ –0.02 and there is no inversion center at this site. This non-zero value of x gives rise to weak Bragg reflections. Examining the energy dependence of these reflections, shown in Fig. 1, we will show that the charge densities on the U1 and U2 sites differ, and that an aspherical distribution must be present around the U2 site.

References
[1] E. Lawrence Bright et al. Phys. Rev. B 100, 134426 (2019)
[2] J. Kokubun et al. Phys. Rev. B 82, 205206 (2010)
[3] S. B. Wilkins et al., Phys. Rev. Lett. 91, 167205 (2003)

Keywords: Anisotropic Resonant Scattering; x-ray scattering; uranium nitride

  • Open Access Logo Lecture (Conference)
    53rd Journées des Actinides international conference, 15.-18.04.2024, Lille, France

Permalink: https://www.hzdr.de/publications/Publ-40852


Breaking the wall of nuclear waste management

Nurjahan, T.; de Assis Dias, F.; Schleicher, E.; Hampel, U.

Abstract

The precise measurement of moisture content in containment buildings is paramount for the decommissioning of nuclear power plants (NPPs). The presence of moisture has been shown to have a significant impact on the radiological safety of concrete structures, particularly by facilitating the migration of radionuclides. This, in turn, has consequences for decisions regarding the reuse and disposal of materials. The present study explores the potential of impedance spectroscopy as a non-destructive, high-sensitivity method for evaluating moisture levels in concrete structures within containment buildings. The method facilitates the precise mapping of moisture distribution in concrete structures, thereby supporting the decommissioning process by enabling the economic recycling of materials. This, in turn, has the potential to reduce costs and minimize the environmental impact by lowering CO2 emissions associated with waste management and new material production.

Keywords: Containment building; Concrete; Moisture content in concrete; Electrical impedance spectroscopy; Nuclear waste management; Economic recycling of concrete

Involved research facilities

  • TOPFLOW Facility
  • Lecture (others)
    Falling Walls Lab 2024, 14.09.2024, Wroclaw, Poland

Permalink: https://www.hzdr.de/publications/Publ-40851


Fundamentals of the U halides

E. Silva, C. L.; Amidani, L.; Bazarkina, E.; Weiß, S.; Kraus, F.; Kvashnina, K.

Abstract

Assessing the nature of bonding as ionic versus covalent is a subject of strong interest in f-element complexes [1]. While spectroscopic techniques reveal the characteristics of f-element bonding, the effort to understand 5f electron systems has been harmed by the lack of high-quality experimental data on actinide compounds to be studied [2-4]. We report here the high energy resolution fluorescence detected (HERFD) recorded for the family of the U(III) and U(IV) halides, named UX3 and UX4 (X=F, Cl, Br, I). The electronic structure of both 5f3 and 5f2 halide families was investigated by HERFD at the U M4 edge which reveals differences in the spectral shape in both families. To interpret the changes and gain insight into the nature of the 5f orbitals, we applied crystal-field multiplet theory to calculate the 3d-4f RIXS maps, and extract the HERFD spectra as cuts of the calculated RIXS maps. We investigated the effect of reducing different contributions to the electron-electron interactions involved in the RIXS process to rationalize the spectral changed observed. We found that that the spectral shape is primarily due to electron-electron interactions, with little influence from crystal field interactions. Small variations of the Slater-Condon integrals result in very good agreement with the changes observed for UX4, while stronger variation of the interaction between the final core-hole and the 5f electrons is needed to partially reproduce changes of the UX3 set. Our analysis indicate the sensitivity of HERFD at the M4 edges to weak changes of the intra-atomic interactions in strongly ionic systems.

References
[1] Tanti, J. et al., Inorganics 6, 88 (2018).
[2] Kvashnina, K. O., and S. M. Butorin. Chemical Communications 58, 327 (2022).
[3] Butorin, S. M. Journal of Chemical Physics 155, 164103 (2021).
[4] Amidani, L. et al., Inorg. Chem. 60, 16286 (2021).

Involved research facilities

Related publications

  • Lecture (Conference)
    52nd Journées des Actinides (JdA), 17.-21.04.2023, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-40849


Room-temperature telecom Si:Te PIN planar photodiodes: A study on optimizing device dimensions

Saif Shaikh, M.; Yang, J.; Wen, S.; Catuneanu, M.-T.; Wang, M.; Erbe, A.; Prucnal, S.; Rebohle, L.; Helm, M.; Jamshidi, K.; Zhou, S.; Berencen, Y.

Abstract

The lack of efficient, cost-effective, room-temperature, and silicon-based photodetectors operating at the telecom bands has posed a persistent challenge in the realm of silicon photonics. One potential solution lies in introducing an impurity band within the silicon bandgap, offering a pathway to create a silicon-based photodetector that not only meets the requirements but also benefits from seamless integration with mature CMOS technology. Here, we report on enhancing device performance by introducing geometric modifications while retaining the doping concentration, device area, and operating conditions. The modified devices showcase improved responsivities, reaching approximately 3 ×10 2 A/W at 1300 nm (O band) and 1 ×10 2 A/W at 1500 nm (C band). These values significantly surpass prior work on Si:Te planar photodetectors, demonstrating an improvement of over 30 times. The noise equivalent power however was found to unavoidably increase by one order of magnitude to 10 6 (W / ̅̅̅̅̅̅ Hz √ ).

Keywords: Telecom-wavelength photodetectors; Tellurium-implanted Si; Silicon Photonics; ion Implantation

Involved research facilities

Related publications

Permalink: https://www.hzdr.de/publications/Publ-40847


Measurement of moisture content in the reactor building during decommissioning of nuclear power plants

Nurjahan, T.; de Assis Dias, F.; Schleicher, E.; Hampel, U.

Abstract

The precise ascertainment of moisture content in the reactor building constitutes a pivotal element in the process of decommissioning nuclear power plants (NPPs). The impact of moisture on the structural integrity and radiological safety of concrete structures is substantial, given its capacity to influence radionuclide migration and inform decisions regarding material reuse or disposal. This study investigates the utilization of impedance spectroscopy as a non-destructive and highly sensitive technique for the evaluation of moisture levels in concrete structures within reactor buildings.

Keywords: Reactor building; Concrete; Moisture content in concrete; Electrical impedance spectroscopy

Involved research facilities

  • TOPFLOW Facility
  • Invited lecture (Conferences)
    Doctoral Colloquium, 04.12.2024, Technische Universität Chemnitz, Germany

Permalink: https://www.hzdr.de/publications/Publ-40846


A Supramolecular Approach to Engineering Living Cells with Enzymes for Adaptive and Recyclable Cascade Synthesis

Wang, S.; Hübner, R.; Karring, H.; Batista, V. F.; Wu, C.

Abstract

Biocatalytic transformation in nature is inherently dynamic, spontaneous, and adaptive, enabling complex chemical synthesis and metabolism. These processes often involve supramolecular recognition among cells, enzymes, and biomacromolecules, far surpassing the capabilities of isolated cells and enzymes used in industrial synthesis. Inspired by nature, here we design a supramolecular approach to equip living cells with these capacities, enabling recyclable, efficient cascade reactions. Our two-step “plug-and-play” methodology begins by coating Escherichia coli cells with guestcontaining polymers (SupraBAC) via supramolecular charge interactions, followed by the introduction of β-cyclodextrin-functionalized host enzymes through host-guest chemistry, creating a robust cell-enzyme complex. This supramolecular coating not only protects cells from various stresses, such as UV radiation, heat, and organic solvents, but also facilitates the overexpression of intracellular enzymes and the attachment of extracellular enzymes within and on SupraBAC. This combination results in efficient multienzyme cascade synthesis, enabling two- and three-step reactions in one pot. Importantly, the multienzyme system can be recycled up to five times without significant loss of activity. Our findings introduce a versatile, adaptive supramolecular coating for whole-cell catalysts, offering a sustainable and efficient solution for complex synthesis in both chemistry and industrial biotechnology.

Involved research facilities

Related publications

  • Angewandte Chemie - International Edition 64(2025), e202416556
    Online First (2024) DOI: 10.1002/anie.202416556

Permalink: https://www.hzdr.de/publications/Publ-40844


Data publication: Investigation of the interactions of microorganisms with uranium in anthropogenic contaminated waters as basis for the development of a bioremediation technology. (Investigación de las interacciones de los microorganismos con el uranio en aguas contaminadas de origen antropogénico como base para el desarrollo de una tecnología de biorremediación)

Newman Portela, A.

Abstract

This dataset supports the investigation of microbial interactions with uranium in anthropogenically contaminated waters. It includes experimental results, microbial community analyses, geochemical characterizations, and spectroscopic data used to evaluate uranium reduction and immobilization processes. The data serve as a foundation for the development of bioremediation technologies aimed at mitigating uranium contamination.

Keywords: Uranium; Mine Water; Bioremediation

Involved research facilities

Related publications

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40842


(Data set) Fermi-liquid behavior of non-altermagnetic RuO2

Wenzel, M.; Uykur, E.; Rößler, S.; Schmidt, M.; Janson, O.; Tiwari, A.; Dressel, M.; Tsirlin, A.

Abstract

1) Data set of the figures in main text and supplementary - Originlab format (Origin Viewer can be used to open these files).

2) FPLO calculations for the representation of the nodal line.

Related publications

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40839


Ultra-Doped Semiconductors by Non-Equilibrium Processing

Zhou, S.; Pastor, D.; Napolitani, E.; Chang, G.-E.

Abstract

Editorail for a special iusse

Involved research facilities

Related publications

Permalink: https://www.hzdr.de/publications/Publ-40837


Scalable Machine Learning for Electronic Structure Theory

Cangi, A.

Abstract

In this presentation, I will discuss our recent advancements in utilizing machine learning to significantly enhance the efficiency of electronic structure calculations [1].
Specifically, I will focus on our efforts to accelerate Kohn-Sham density functional theory calculations by incorporating deep neural networks within the Materials Learning Algorithms framework [2,3]. Our results demonstrate substantial gains in calculation speed for metals across their melting point. Additionally, our implementation of automated machine learning has resulted in significant savings in computational resources when identifying optimal neural network architectures, laying the foundation for large-scale investigations [4].
Furthermore, I will present our most recent breakthrough, which enables neural-network-driven electronic structure calculations for systems containing over 100,000 atoms [5]. This achievement opens up new avenues for studying complex materials systems that were previously computationally intractable.

References
[1] L. Fiedler, K. Shah, M. Bussmann, A. Cangi, Phys. Rev. Materials, 6, 040301 (2022)
[2] A. Cangi, J. A. Ellis, L. Fiedler, D. Kotik, N. A. Modine, V. Oles, G. A. Popoola, S. Rajamanickam, S. Schmerler, J. A. Stephens, A. P. Thompson, Phys. Rev. B 104, 035120 (2021).
[3] J. Ellis, L. Fiedler, G. Popoola, N. Modine, J. Stephens, A. Thompson, A. Cangi, S. Rajamanickam, Phys. Rev. B, 104, 035120 (2021)
[4] L. Fiedler, N. Hoffmann, P. Mohammed, G. Popoola, T. Yovell, V. Oles, J. Austin Ellis, S. Rajamanickam, A. Cangi, Mach. Learn.: Sci. Technol., 3, 045008 (2022)
[5] L. Fiedler, N. Modine, S. Schmerler, D. Vogel, G. Popoola, A. Thompson, S. Rajamanickam, A. Cangi, npj. Comput. Mater., 9, 115 (2023)

Keywords: Electronic structure theory; Density functional theory; Machine learning; Deep learning; Artificial intelligence; Neural networks; Materials; Chemistry

Involved research facilities

  • Data Center
  • Invited lecture (Conferences)
    Theoretical Chemistry Colloquium, 21.01.2025, Marburg, Germany

Permalink: https://www.hzdr.de/publications/Publ-40836


Successful implementation of online educational lectures of the German Society for Radiation Oncology (DEGRO)

Büttner, M.; Melton, P.; Fietkau, R.; Petersen, C.; Krause, M.; Borgmann, K.; Wolf, U.; Niyazi, M.; Christiansen, H.; Höller, U.; Schmitt, D.; Käsmann, L.; Linde, P.; DF, F.; Ziegler, S.; Bresch, A.; Mäurer, M.

Abstract

Purpose Modern digital teaching formats have become increasingly important in recent years, in part due to the COVID-19
pandemic. In January 2021, an online-based webinar series was established by the German Society for Radiation Oncology
(DEGRO) and the young DEGRO (yDEGRO) working group. In the monthly 120-minute courses, selected lecturers teach
curricular content as preparation for the board certification exam for radiation oncology.
Methods The evaluation of the 24 courses between 01.2021 and 12.2022 was performed using a standardized questionnaire
with 21 items (recording epidemiological characteristics of the participants, didactic quality, content quality). A Likert scale
(1–4) was used in combination with binary and open-ended questions.
Results A combined total of 4200 individuals (1952 in 2021 and 2248 in 2022) registered for the courses, and out of
those, 934 participants (455 in 2021 and 479 in 2022) later provided evaluations for the respective courses (36% residents,
35% specialists, 21% medical technicians for radiology [MTR], 8% medical physics experts [MPE]). After 2 years, 74%
of the DEGRO Academy curriculum topics were covered by the monthly webinars. The overall rating by participants
was positive (mean 2021: 1.33 and 2022: 1.25) and exceeded the curriculum offered at each site for 70% of participants.
Case-based learning was identified as a particularly well-rated method.

Keywords: Medical education; e-learning; Online webinar; Teaching format; Radiation oncology

Permalink: https://www.hzdr.de/publications/Publ-40834


The value of subcutaneous xenografts for individualised radiotherapy in HNSCC: Robust gene signature correlates with radiotherapy outcome in patients and xenografts

Linge, A.; Patil, S.; Grosser, M.; Lohaus, F.; Gurtner, K.; Kemper, M.; Gudziol, V.; Haim, D.; Nowak, A.; Tinhofer, I.; Zips, D.; Guberina, M.; Stuschke, M.; Balermpas, P.; Rödel, C.; Schäfer, H.; Grosu, A.; Abdollahi, A.; Debus, J.; Ganswindt, U.; Belka, C.; Pigorsch, S.; Combs, S.; Boeke, S.; Gani, C.; Jöhrens, K.; Baretton, G.; Löck, S.; Baumann, M.; Krause, M.

Abstract

Purpose: To assess the robustness of prognostic biomarkers and molecular tumour subtypes developed for patients
with head and neck squamous cell carcinoma (HNSCC) on cell-line derived HNSCC xenograft models, and to
develop a novel biomarker signature by combining xenograft and patient datasets.
Materials and methods: Mice bearing xenografts (n = 59) of ten HNSCC cell lines and a retrospective, multicentre
patient cohort (n = 242) of the German Cancer Consortium-Radiation Oncology Group (DKTK-ROG) were
included. All patients received postoperative radiochemotherapy (PORT-C). Gene expression analysis was con-
ducted using GeneChip Human Transcriptome Arrays. Xenografts were stratified based on their molecular
subtypes and previously established gene classifiers. The dose to control 50 % of tumours (TCD50) was compared
between these groups. Using differential gene expression analyses combining xenograft and patient data, a gene
signature was developed to define risk groups for the primary endpoint loco-regional control (LRC).
Results: Tumours of mesenchymal subtype were characterized by a higher TCD50 (xenografts, p < 0.001) and
lower LRC (patients, p < 0.001) compared to the other subtypes. Similar to previously published patient data,
hypoxia- and radioresistance-related gene signatures were associated with high TCD50 values. A 2-gene signa-
ture (FN1, SERPINE1) was developed that was prognostic for TCD50 (xenografts, p < 0.001) and for patient
outcome in independent validation (LRC: p = 0.007).
Conclusion: Genetic prognosticators of outcome for patients after PORT-C and subcutaneous xenografts after
primary clinically relevant irradiation show similarity. The identified robust 2-gene signature may help to guide
patient stratification, after prospective validation. Thus, xenografts remain a valuable resource for translational
research towards the development of individualized radiotherapy.

Keywords: Head and neck squamous cell carcinoma; Gene signature; Postoperative radiochemotherapy; Xenograft; Molecular subtypes; Hypoxia; Radiosensitivity

Involved research facilities

  • OncoRay

Permalink: https://www.hzdr.de/publications/Publ-40832


Clinical research for global needs of radiation oncology

Baumann, M.; Bacchus, C.; MC, A.; RP, C.; Deutsch, E.; Georg, D.; Haustermans, K.; Hoskin, P.; Krause, M.; EF, L.; AWM, L.; Löck, S.; BV, O.; DI, T.; an, d. H. U.; Valentini, V.; Overgaard, J.

Abstract

The demand for radiotherapy (RT) is increasing worldwide due to
population growth as prominently seen in Africa, and increasing popu-
lation age as prominently seen in Europe. Increasing age, particularly
over 60 years, is associated with a significantly increased risk of cancer.
Additionally, RT is more often prescribed over other modalities, such as
major surgery, for frail, multimorbid and elderly patients. In some re-
gions of the world, more cancers are now being detected earlier and
treated more effectively, leading to longer survival but also to the risk of
recurrence, new malignancies and late effects. More than half of all
cancer patients benefit from RT [1]. However, despite its cost-
effectiveness, RT is currently either not available at all or only for a
small proportion of cancer patients in a disturbingly high number of
countries worldwide [1]. In many other countries, including some high-
income countries (HIC), the RT capacity is already limited, causing long
waiting lists. In general, RT services are frequently insufficiently pre-
pared for the growing numbers of patients expected in the coming years.
These observations clearly call for major strategic investments in RT,
particularly in low and middle income countries (LMIC), in parallel with
general improvements in health care systems. The global radiation
oncology community needs to be alert and vocal in order to accelerate
relevant policy advances, which might otherwise be deprioritized,
bearing in mind the many international and national crises.
Research in radiation oncology may have additional positive impact
for cancer patients worldwide by addressing global needs, frameworks
and resources. Conversely, rapid scientific advances have the potential
to further exacerbate existing disparities in access to high quality cancer
care between LMIC and HIC [2]. A recent review by Jaffrey and col-
leagues of the status of RT discussed how the global radiation oncology
community could formulate a more integrative ‘diagonal approach’, in
which the agendas of science-driven advances in individual outcomes
and the socio-technological task of global cancer control can be aligned
to bring the benefits of RT to cancer patients everywhere [3]. This 2024
Radiotherapy & Oncology New Year’s Editorial looks at some contem-
porary examples of such a diagonal approach for global impact, with a
focus on clinical research and trials.

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40831


Type I conventional dendritic cells and CD8(+) T cells predict favorable clinical outcome of head and neck squamous cell carcinoma patients

Kirchner, J.; Plesca, I.; Rothe, R.; Resag, A.; Löck, S.; Benesova, I.; Rupp, L.; Linge, A.; Wehner, R.; Krause, M.; Schmitz, M.

Abstract

Head and neck squamous cell carcinoma (HNSCC) is one of the most common
tumor entities worldwide, with human papillomavirus (HPV) infection
contributing to cancer development. Conventional therapies achieve only
limited efficiency, especially in recurrent or metastatic HNSCC. As the immune
landscape decisively impacts the survival of patients and treatment efficacy, this
s t u d y c o m p r e h e n s i v e l y i n v e s t i g a t e d t h e i m m u n o l o g i c a l t u m o r
microenvironment (TME) and its association with patient outcome, with special
focus on several dendritic cell (DC) and T lymphocyte subpopulations. Therefore,
formalin-fixed paraffin-embedded tumor samples of 56 HNSCC patients, who
have undergone resection and adjuvant radiotherapy, were analyzed by multiplex
immunohistochemistry focusing on the detailed phenotypic characterization
and spatial distribution of DCs, CD8+ T cells, and T-helper cell subsets in
different tumor compartments. Immune cell densities and proportions were
correlated with clinical characteristics of the whole HNSCC cohort and
different HPV- or hypoxia-associated subcohorts. Tumor stroma was highly
infiltrated by plasmacytoid DCs and T lymphocytes. Among the T-helper cells
and CD8+ T cells, stromal regulatory T cells and intraepithelial exhausted CD8+ T
cells expressing programmed cell death protein-1 (PD-1+) and/or lymphocyte-
activation gene-3 (LAG-3+) were the predominant phenotypes, indicating an
immunosuppressive TME. HPV-associated tumors showed significantly higher
infiltration of type I and type II conventional DCs (cDC1, cDC2) as well as several
CD8+ T cell phenotypes including exhausted, activated, and proliferating T cells.
On the contrary, tumors with hypoxia-associated gene signatures exhibited
reduced infiltration for these immune cells. By multivariate Cox regression,
immune-related prognostic factors were identified. Patient clusters defined by
high infiltration of DCs and T lymphocytes combined with HPV positivity or low
hypoxia showed significantly prolonged survival. Thereby, cDC1 and CD8+ T cells
emerged as independent prognostic factors for local and distant recurrence.
These results might contribute to the implementation of an immune cell
infiltration score predicting HNSCC patients’ survival and such patient
stratification might improve the design of future individualized radiochemo-
(immuno)therapies.

Keywords: dendritic cells; head and neck squamous cell carcinoma; human papilloma virus; hypoxia; multiplex imaging; tumor microenvironment; T cells; spatial biology

Involved research facilities

  • OncoRay

Permalink: https://www.hzdr.de/publications/Publ-40830


Treatment-related survival patterns in diffuse intrinsic pontine glioma using a historical cohort: A report from the European Society for Pediatric Oncology DIPG/DMG Registry

Baugh, J. N.; Veldhuijzen van Zanten, S.; Fiocco, M.; Colditz, N.; Hoffmann, M.; Janssens, G. O.; Valentini, C.; Hargrave, D.; Wiese, M.; von Bueren, A. O.; Karremann, M.; Perwein, T.; Nussbaumer, G.; Benesch, M.; Sturm, D.; Gielen, G. H.; Krause, M.; Eyrich, M.; Hoving, E. W.; Bison, B.; van Vuurden, D. G.; Kramm, C. M.

Abstract

Background. Our aim is to investigate the association of treatment with survival in patients with diffuse intrinsic
pontine glioma (DIPG) by examining 6 historical treatment paths.
Methods. We retrospectively analyzed data from 409 patients with radiologically centrally reviewed DIPG, sourced
from the German Society of Pediatric Oncology and Hematology HIT-HGG trial database and the SIOPE-DIPG/DMG
Registry. Survival outcomes were estimated using the Kaplan–Meier method, and univariable and multivariable
Cox proportional hazard models were estimated to study treatment effects.
Results. The median overall survival (OS) from diagnosis was 11.2 months (95% confidence interval [CI], 10.5–
11.9). Patients who by choice received no frontline treatment had an OS of 3.0 months (95% CI, 2.0–4.0), while
those treated with radiation therapy (RT) alone had a median OS of 10.4 months (95% CI, 9.1–11.8). Those receiving
RT combined with chemotherapy had the longest median OS of 11.7 months (95% CI, 10.8–12.6). The median post-
progression survival (PPS) was 4.1 months (95% CI, 3.5–4.7). Patients who relapsed and did not receive treatment
had a PPS of 2.2 months (95% CI, 1.8–2.6), while those treated with chemotherapy alone had a PPS of 4.4 months
(95% CI, 3.7–5.0), and those who underwent reirradiation, with or without chemotherapy, had the longest survival
after relapse of 6.6 months (95% CI, 5.3–8.0). Treatment differences remained significant in multivariable analysis
adjusted for age and symptom duration in both diagnosis and relapse setting.
Conclusions. This study shows increased survival outcomes associated with radiation and chemotherapy treat-
ment or a combination thereof, at diagnosis and relapse, in a historical DIPG cohort.

Involved research facilities

  • OncoRay

Permalink: https://www.hzdr.de/publications/Publ-40829


A review of the clinical introduction of 4D particle therapy research concepts

Knäusl, B.; Belotti, G.; Bertholet, J.; Daartz, J.; Flampouri, S.; Hoogeman, M.; Knopf, A. C.; Lin, H.; Moerman, A.; Paganelli, C.; Rucinski, A.; Schulte, R.; Shimizu, S.; Stützer, K.; Zhang, X.; Zhang, Y.; Czerska, K.

Abstract

Background and purpose: Many 4D particle therapy research concepts have been recently translated into clinics,
however, remaining substantial differences depend on the indication and institute-related aspects. This work
aims to summarise current state-of-the-art 4D particle therapy technology and outline a roadmap for future
research and developments.
Material and methods: This review focused on the clinical implementation of 4D approaches for imaging, treat-
ment planning, delivery and evaluation based on the 2021 and 2022 4D Treatment Workshops for Particle Therapy
as well as a review of the most recent surveys, guidelines and scientific papers dedicated to this topic.
Results: Available technological capabilities for motion surveillance and compensation determined the course of
each 4D particle treatment. 4D motion management, delivery techniques and strategies including imaging were
diverse and depended on many factors. These included aspects of motion amplitude, tumour location, as well as
accelerator technology driving the necessity of centre-specific dosimetric validation. Novel methodologies for X-
ray based image processing and MRI for real-time tumour tracking and motion management were shown to have
a large potential for online and offline adaptation schemes compensating for potential anatomical changes over
the treatment course. The latest research developments were dominated by particle imaging, artificial intelli-
gence methods and FLASH adding another level of complexity but also opportunities in the context of 4D
treatments.
Conclusion: This review showed that the rapid technological advances in radiation oncology together with the
available intrafractional motion management and adaptive strategies paved the way towards clinical
implementation.

Keywords: Intrafractional motion; Particle therapy; Motion management; 4D imaging; Adaptive workflows; 4D Trea

Permalink: https://www.hzdr.de/publications/Publ-40828


Platform for laser-driven X-ray diagnostics of heavy-ion heated extreme states of matter

Hesselbach, P.; Lütgert, J.; Bagnoud, V.; Belikov, R.; Humphries, O.; Lindqvist, B.; Schaumann, G.; Sokolov, A.; Tauschwitz, A.; Varentsov, D.; Weyrich, K.; Winkler, B.; Yu, X.; Zielbauer, B.; Kraus, D.; Riley, D.; Major, Z.; Neumayer, P.

Abstract

We report on commissioning experiments at the high-energy, high-temperature (HHT) target area at the GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, combining for the first time intense pulses of heavy ions from the SIS18 synchrotron with high-energy laser pulses from the PHELIX laser facility. We demonstrate the use of X-ray diagnostic techniques based on intense laser-driven X-ray sources, which will allow probing of large samples volumetrically heated by the intense heavy-ion beams. A new target chamber as well as optical diagnostics for ion-beam characterization and fast pyrometric temperature measurements complement the experimental capabilities. This platform is designed for experiments at the future Facility for Antiproton and Ion Research in Europe GmbH (FAIR), where unprecedented ion-beam intensities will enable the generation of millimeter-sized samples under high-energy-density conditions.

Permalink: https://www.hzdr.de/publications/Publ-40827


Reconstruction of nanoparticle size distribution in laser-shocked matter from small-angle X-ray scattering via neural networks

He, Z.; Lütgert, J.; Stevenson, M. G.; Heuser, B.; Ranjan, D.; Qu, C.; Kraus, D.

Abstract

Small-angle X-ray scattering (SAXS) has been widely used as a microstructure characterization technology. In this work, a fully connected dense forward network is applied to inversely retrieve the mean particle size and particle distribution from SAXS data of samples dynamically compressed with high-power lasers and probed with X-ray free electron lasers. The trained network allows automatic acquisition of microstructure information, performing well in predictions on single-species nanoparticles on the theoretical model and in situ experimental data. We evaluate our network by comparing it with other methods, revealing its reliability and efficiency in dynamic experiments, which is of great value for in situ characterization of materials under high-power laser-driven dynamic compression.

Permalink: https://www.hzdr.de/publications/Publ-40826


Towards highly accurate diagnostics of extreme states of matter with x-ray Thomson scattering

Dornheim, T.

Abstract

Matter under extreme densities, temperatures and pressures is ubiquitous throughout our universe
and naturally occurs in a variety of astrophysical objects, including giant planet interiors. On Earth,
such extreme states are important for technological applications such as inertial fusion energy
(IFE), where both the fuel capsule and the ablator material have to traverse this warm dense matter
regime in a controlled way to reach ignition. In the laboratory, warm dense matter is created in large
research facilities such as the European XFEL in Germany using a variety of techniques. Here, a key
challenge is given by the accurate diagnostics of the created samples due to the extreme conditions
and the ultrafast time scales. Over the last years, the X-ray Thomson scattering (XRTS) technique---
also known as inelastic X-ray scattering---has emerged as a promising method of diagnostics as it
is, in principle, capable of giving microscopic insights into the probed sample in the form of the
electronic dynamic structure factor [1]. In practice, however, the interpretation of XRTS
measurements has relied on theoretical models that are based on a number of de-facto
uncontrolled assumptions. Consequently, the quality of the thus inferred system parameters has
remained unclear. Here, I present an overview of a new approach that allows for the model-free
interpretation of XRTS spectra in the imaginary-time domain [2,3]. The latter naturally emerges in
Feynman’s celebrated path integral formulation of statistical mechanics and, by definition, contains
the same information as the usual spectral epresentation, only in an a-priori unfamiliar
representation. At the same time, working in the imaginary-time allows one to deconvolve the
physical nformation from effects due to the X-ray source and the detector. This, in turn, opens up
the way for the model-free extraction of important system parameters such as the temperature [2]
without the need for any
approximations or simulations.
[1] S. H. Glenzer and R. Redmer, X-ray Thomson scattering in high energy density plasmas, Rev. Mod.
Phys. 81, 1625 (2009)
[2] T. Dornheim et al., Accurate temperature diagnostics for matter under extreme conditions,
Nature Commun. 13, 7911 (2022)
[3] T. Dornheim et al., Physical insights from imaginary-time correlation functions, Matt. Radiat.
Extremes 8, 056601 (2023)

  • Lecture (Conference)
    17th Latin American Workshop on Plasma Physics, 20.-23.01.2025, Santiago de Chile, Chile

Permalink: https://www.hzdr.de/publications/Publ-40823


Proton versus photon therapy for esophageal cancer – A trimodality strategy

Mortensen, H. R.; Populaire, P.; Hoffmann, L.; Moeller, D. S.; Appelt, A.; Nafteux, P.; Muijs, C. T.; Grau, C.; Hawkins, M. A.; Troost, E. G. C.; Defraene, G.; Canters, R.; Clarke, C. S.; Weber, D. C.; Korevaar, E. W.; Haustermans, K.; Nordsmark, M.; Val, G.; Achiam, M. P.; Sheraz, R. M.; Ganesh, R.; Maaike, B.; Daniele, S.; Ester, O.; Jerome, D.; Vincent, G.; Gilles, C.; Johannes, L.; Paula, L.; Hedwig, M. l.; Camilla, S. B.; Mai, L. E.; Maria, F. J.; Gloria, V. F.; Rebecca, B.

Abstract

PROTECT is an unblinded randomized phase III study for patients
with operable EC or EGC receiving nCXT (standard of care) or nCPT
(intervention). The radiation dose is either 41.4 Gy in 23 fractions, five
fractions per week or 50.4 Gy in 28 fractions, five fractions per week
delivered concurrently with weekly carboplatin (AUC 2), and paclitaxel
(50 mg/m2), five cycles in total.
Patients will be randomized (1:1) to either nCXT or nCPT (See
Fig. 1). Stratification for histopathology (adenocarcinoma versus

squamous cell carcinoma), planned surgical technique (open versus
minimal invasive/robotic or hybrid) and site (proton center and
collaborating photon centers) will be performed. Each proton center and
collaborating photon centers will declare a standard treatment dose of
either 50.4 Gy or 41.4 Gy and hence, stratification for site will reflect
total radiotherapy dose as well.
All patients will receive standard diagnostic work-up including
esophagogastroduodenoscopy with biopsies, UICC TNM clinical staging
8th edition [12], diagnostic FDG-PET scan, and baseline lung and heart
function tests. Patients will be seen weekly during radiotherapy, every
second week after nCRT until surgery as well as post-operatively (up to
three months), and at eight specified time points for 5 years of follow-up.

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40822


Patterns of practice of image guided particle therapy for cranio-spinal irradiation: A site specific multi-institutional survey of European Particle Therapy Network

Trnkova, P.; Dasu, A.; Placidi, L.; Stock, M.; Toma-Dasu, I.; Brouwer, C. L.; Gosling, A.; Jouglar, E.; Kristensen, I.; Martin, V.; Moinuddin, S.; Pasquie, I.; Peters, S.; Pica, A.; Plaude, S.; Righetto, R.; Rombi, B.; Thariat, J.; van der Weide, H.; Hoffmann, A. L.; Bolsi, A.

Abstract

Purpose: To investigate the current practice patterns in image-guided particle therapy (IGPT) for cranio-spinal
irradiation (CSI).
Methods: A multi-institutional survey was distributed to European particle therapy centres to analyse all aspects
of IGPT. Based on the survey results, a Delphi consensus analysis was developed to define minimum requirements
and optimal workflow for clinical practice. The centres participating in the institutional survey were invited to
join the Delphi process.
Results: Eleven centres participated in the survey. Imaging for treatment planning was rather similar among the
centres with Computed Tomography (CT) being the main modality. For positioning verification, 2D IGPT was
more commonly used than 3D IGPT. Two centres performed routinely imaging for plan adaptation, by the rest ad
hoc. Eight centres participated in the Delphi consensus analysis. The full consensus was reached on the use of CT
imaging without contrast for treatment planning and the role of magnetic resonance imaging (MRI) in target and
organs-at-risk delineation. There was an agreement on the necessity to perform patient position verification and
correction before each isocentre. The most important outcome was the clear need for standardization and
harmonization of the workflow.
Conclusion: There were differences in CSI IGPT clinical practice among the European particle therapy centres.
Moreover, the optimal workflow as identified by experts was not yet reached. There is a strong need for
consensus guidelines. The state-of-the-art imaging technology and protocols need to be implemented into clinical
practice to improve the quality of IGPT for CSI.

Keywords: Cranio-spinal axis; Proton therapy; Image guided proton therapy

Involved research facilities

  • OncoRay

Permalink: https://www.hzdr.de/publications/Publ-40821


Cancer Stem Cells as a Therapeutic Target: Current Clinical Development and Future Prospective

Philchenkov, A.; Dubrovska, A.

Abstract

The key role of cancer stem cells (CSCs) in tumor development and therapy resistance makes them essential biomarkers and therapeutic targets. Numerous agents targeting CSCs, either as monotherapy or as part of combination therapy, are currently being tested in clinical trials to treat solid tumors and hematologic malignancies. Data from ongoing and future clinical trials testing novel approaches to target tumor stemness-related biomarkers and pathways may pave the way for further clinical development of CSC-targeted treatments and CSC-guided selection of therapeutic regimens. In this concise review, we discuss recent progress in developing CSC-directed treatment approaches, focusing on clinical trials testing CSC-directed therapies. We also consider the further development of CSC-assay-guided patient stratification and treatment personalization.

Keywords: cancer stem cells; leukemia stem cells; patient stratification; clinical trials; treatment personali

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40820


New advances of the androgen receptor in prostate cancer: report from the 1st International Androgen Receptor Symposium

Mehralivand, S.; Thomas, C.; Puhr, M.; Claessens, F.; van de Merbel, A. F.; Dubrovska, A.; Jenster, G.; Bernemann, C.; Sommer, U.; Erb, H. H. H.

Abstract

The androgen receptor (AR) is a crucial player in various aspects of male reproduction and has been associated
with the development and progression of prostate cancer (PCa). Therefore, the protein is the linchpin of current PCa
therapies. Despite great research efforts, the AR signaling pathway has still not been deciphered, and the emergence
of resistance is still the biggest problem in PCa treatment. To discuss the latest developments in AR research, the “1st
International Androgen Receptor Symposium” offered a forum for the exchange of clinical and scientific innovations
around the role of the AR in prostate cancer (PCa) and to stimulate new collaborative interactions among leading
scientists from basic, translational, and clinical research. The symposium included three sessions covering preclinical
studies, prognostic and diagnostic biomarkers, and ongoing prostate cancer clinical trials. In addition, a panel discus-
sion about the future direction of androgen deprivation therapy and anti-AR therapy in PCa was conducted. There-
fore, the newest insights and developments in therapeutic strategies and biomarkers are discussed in this report.

Keywords: Androgen receptor; PCa; NR3C4; Androgen deprivation therapy

Involved research facilities

  • OncoRay

Permalink: https://www.hzdr.de/publications/Publ-40819


Targeting the glutamine metabolism to suppress cell proliferation in mesenchymal docetaxel-resistant prostate cancer

Beier, A.-M. K.; Ebersbach, C.; Siciliano, T.; Scholze, J.; Hofmann, J.; Hönscheid, P.; Baretton, G. B.; Woods, K.; Guezguez, B.; Dubrovska, A.; Markowitsch, S. D.; Thomas, C.; Puhr, M.; Erb, H. H. H.

Abstract

Docetaxel (DX) serves as a palliative treatment option for metastatic prostate cancer (PCa). Despite initial remission, acquired DX
resistance is inevitable. The mechanisms behind DX resistance have not yet been deciphered, but a mesenchymal phenotype is
associated with DX resistance. Mesenchymal phenotypes have been linked to metabolic rewiring, obtaining most ATP production
by oxidative phosphorylation (OXPHOS) powered substantially by glutamine (Gln). Likewise, Gln is known to play an essential role in
modulating bioenergetic, redox homeostasis and autophagy. Herein, investigations of Gln deprivation on DX-sensitive and
-resistant (DR) PCa cells revealed that the DR cell sub-lines were susceptible to Gln deprivation. Mechanistically, Gln deprivation
reduced OXPHOS and ATP levels, causing a disturbance in cell cycle progression. Genetic and chemical inhibition of the Gln-
metabolism key protein GLS1 could validate the Gln deprivation results, thereby representing a valid therapeutic target. Moreover,
immunohistological investigation of GLS1 revealed a high-expressing GLS1 subgroup post-docetaxel failure, exhibiting low overall
survival. This subgroup presents an intriguing opportunity for targeted therapy focusing on glutamine metabolism. Thus, these
findings highlight a possible clinical rationale for the chemical inhibition of GLS1 as a therapeutic strategy to target mesenchymal
DR PCa cells, thereby delaying accelerated tumour progression.

Involved research facilities

  • OncoRay

Permalink: https://www.hzdr.de/publications/Publ-40818


Altered ACE2 and interferon landscape in the COVID-19 microenvironment correlate with the anti-PD-1 response in solid tumors

Subbarayan, K.; Al-Samadi, A.; Schäfer, H.; Massa, C.; Salo, T.; Biehl, K.; Vaxevanis, C. K.; Ulagappan, K.; Reimers, M.; Drexler, F.; Moreiro-Soto, A.; Bachmann, M.; Seliger, B.

Abstract

Angiotensensin-converting enzyme-2 (ACE2) is a receptor for SARS-CoV-2, allowing the virus to enter cells. Although tumor patients infected by SARS-CoV-2 often have a worse outcome, the expression, function and clinical relevance of ACE2 in tumors has not yet been thoroughly analyzed. In this study, RNA sequencing (RNA-seq) data from tumors, adjacent tissues and whole blood samples of COVID-19 patients from genome databases and from tumor cell lines and endothelial cells infected with different SARS-CoV-2 variants or transfected with an ACE2 expression vector (ACE2high) or mock (ACE2low) were analyzed for the expression of ACE2 and immune response relevant molecules in silico or by qPCR, flow cytometry, Western blot and/or RNA-seq. The differential expression profiles in ACE2high vs. ACE2low cells correlated with available SARS-CoV-2 RNA-seq datasets. ACE2high cells demonstrated upregulated mRNA and/or protein levels of HLA class I, programmed death ligand 1 (PD-L1), components of the antigen processing machinery (APM) and the interferon (IFN) signaling pathway compared to ACE2low cells. Co-cultures of ACE2high cells with peripheral blood mononuclear cells increased immune cell migration and infiltration towards ACE2high cells, apoptosis of ACE2high cells, release of innate immunity-related cytokines and altered NK cell-mediated cytotoxicity. Thus, ACE2 expression was associated in different model systems and upon SARS-CoV-2 infection with an altered host immunogenicity, which might influence the efficacy of immune checkpoint inhibitors. These results provide novel insights into the (patho)physiological
role of ACE2 on immune response-relevant mechanisms and suggest an alternative strategy to reduce COVID-19 severity in infected tumor patients targeting the ACE2-induced IFN-PD-L1 axis.

Keywords: SARS-CoV-2; Immune escape; Immune response; Tumors; Immunotherapy

Involved research facilities

  • ZRT

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40817


Oberflächenfunktionalisierung von Materialien für den Anodenkreislauf von PEM-Elektrolyseuren zur Beeinflussung der Sauerstoffblasenbildung

Heinrich, J.; Schwarzenberger, K.; Yang, X.; Eckert, K.

Abstract

Die Protonenaustauschmembran (PEM)-Elektrolyse ist eines der am häufigsten verwendeten Verfahren zur Wasserstoffgewinnung. Um die PEM-Elektrolyse im Rahmen der „Power-to-Gas“-Strategie wirtschaftlich einzusetzen, muss ihre Effizienz weiter gesteigert werden. Ein wichtiger Ansatzpunkt ist eine verbesserte Sauerstoffabtrennung im Anodenkreislauf, was die Überspannung reduziert und den Wärmeübergang bei der Kühlung des Prozesswassers erhöht. Ziel der Arbeit ist deshalb, die Affinität des gelösten Sauerstoffs als unpolares Gas zu den Materialien im Anodenkreislauf durch eine Oberflächenfunktionalisierung zu beeinflussen. Dazu werden Verfahren wie die plasmaunterstützte chemische Gasphasenabscheidung (PECVD) oder Laserstrukturierung (DLIP - Direct Laser Interference Patterning) [1] eingesetzt.

Die resultierenden Oberflächen werden durch Kontaktwinkelmessungen hinsichtlich ihrer Hydrophilie/Hydrophobie und durch Röntgenphotoelektronenspektroskopie (XPS) hinsichtlich ihrer elementaren Zusammensetzung und der Veränderung der Substratoberflächen durch die Funktionalisierung charakterisiert [2]. Dabei ist festzustellen, dass die Stabilität der Beschichtung und ihre Auswirkungen auf die Benetzbarkeit stark von den umgebenden Medien abhängen. Mittels Konfokalmikroskopie und optischer Aufnahmen wird der Einfluss der Oberflächenstruktur und -funktionalisierung auf die Dynamik der sich bildenden Sauerstoffblasen demonstriert und analysiert [2].
Diese Arbeit liefert erste Erkenntnisse darüber, wie die Sauerstoffabscheidung im Anodenkreislauf von PEM-Elektrolyseuren durch Oberflächenfunktionalisierung verbessert werden kann. Abhängig von den Oberflächeneigenschaften kann nicht nur die Anzahl der Nukleationsstellen und das Gesamtvolumen der Sauerstoffblasen beeinflusst werden, sondern auch die Blasengrößenverteilung und das Ablöseverhalten der Blasen von der Oberfläche.

[1] Krause, L., Skibińska, K., Rox, H., Baumann, R., Marzec, M. M., Yang, X., Mutschke, G., Żabiński, P., Lasagni, A. F., Eckert, K. (2023). Hydrogen Bubble Size Distribution on Nanostructured Ni Surfaces: Electrochemically Active Surface Area Versus Wettability. ACS Applied Materials & Interfaces, 15(14), 18290-18299.
[2] Heinrich, J., Ränke, F., Schwarzenberger, K., Yang, X., Baumann, R., Marzec, M., Lasagni, A. F., Eckert, K. (2023). Functionalization of Ti64 via Direct Laser Interference Patterning and Its Influence on Wettability and Oxygen Bubble Nucleation, submitted to Langmuir.

  • Lecture (Conference)
    Jahrestreffen DECHEMA/VDI Grenzflächenbestimmte Systeme & Prozesse, Kristallisation, Mech. Flüssigketsabtrennung, Partikelmesstechnik, 27.02.2024, Frankfurt, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40816


Prompt Gamma-Ray Yield Measurements for Treatment Verification in Proton Therapy

Urban, K.; Kögler, T.; Junghans, A.; Müller, S.

Abstract

In December 2023, I started my PhD studies at Helmholtz-Zentrum Dresden – Rossendorf. The aim of my work is to determine proton-induced photon yields, which are urgently needed for range verification in proton therapy. Therefore, we will measure the yield for incident proton energies between 70 and 230 MeV on typical medical phantoms (targets), which are used e.g. for clinical quality assurance.
Prompt gamma-rays are emitted during the de-excitation of excited nuclei produced by nuclear reactions between the protons and target nuclei of the human tissue. They are called prompt, because the mean lifetime of the excited nuclear states is in the range of 10⁻¹⁰ … 10⁻²⁰ s. Thus, the gamma-rays are emitted immediately after the nuclear reaction. As the cross section of these nuclear reactions is strongly dependent on the proton energy, the prompt gamma-ray production is correlated to the deposited dose. Therefore, prompt gamma-ray based methods are suitable for treatment verification in proton therapy. In particular, the most promising methods are Prompt Gamma-Ray Timing (PGT), Prompt Gamma-Ray Imaging (PGI) and Prompt Gamma-Ray Spectroscopy (PGS).In order to apply these methods in the clinics, the main idea is to compare the measured gamma-ray spectra acquired during the treatment with target spectra gained by simulations based on the patient information and the treatment planning.
However, presently, common Monte Carlo particle transport codes, e.g., Geant4 or MCNP6, display significant deviations between simulated and experimentally measured spectra. With our measurements, we therefore aim to contribute to the data of and thereby improve the models of existing particle transport codes, bringing predicted prompt gamma-ray spectra into agreement with the measured ones.

Keywords: proton therapy; range verification; prompt gamma rays; nuclear data

Involved research facilities

Related publications

  • Poster
    Radiations for Health, 08.-13.09.2024, Saint-Pierre d'Oléron, Frankreich
  • Lecture (others)
    Neutron Resonance Analysis School, 13.-17.05.2024, Geel, Belgien

Permalink: https://www.hzdr.de/publications/Publ-40814


Projekt ThaXonian

Herrmannsdörfer, T.

Abstract

es hat kein aussagefähiges Abstract vorgelegen

Involved research facilities

  • High Magnetic Field Laboratory (HLD)
  • Lecture (Conference)
    8. Life Sciences Forum Sachsen, 26.11.2024, Leipzig, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40813


Magnetic fields for neurology - ThaXonian

Herrmannsdörfer, T.

Abstract

es hat kein aussagefähiges Abstract vorgelegen

Involved research facilities

  • High Magnetic Field Laboratory (HLD)
  • Lecture (Conference)
    EMFL Days, 16.-18.09.2024, Prag, Tschechien

Permalink: https://www.hzdr.de/publications/Publ-40812


Magnetic-field assisted therapy for neurodegenerative diseases

Herrmannsdörfer, T.

Abstract

es hat kein aussagefähiges Abstract vorgelegen

Involved research facilities

  • High Magnetic Field Laboratory (HLD)
  • Lecture (Conference)
    EMFL school, 19.04.2024, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40811


Electromagnetic field stimulation rescues defects in Amyotrophic Lateral Sclerosis (ALS)

Herrmannsdörfer, T.

Abstract

es hat kein aussagefähiges Abstract vorgelegen

Involved research facilities

  • High Magnetic Field Laboratory (HLD)
  • Lecture (Conference)
    DPG - Frühjahrstagung, 17.-22.03.2024, Berlin, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40810


Beta-decay feeding intensity distribution of 64Mn

von Seeger, W. W.; DeYoung, P. A.; Spyrou, A.; Karampagia, S.; Brown, E. F.; Ahn, S.; Crider, B. P.; Dombos, A. C.; Hitt, G. W.; Langer, C.; Lewis, R.; Liddick, S. N.; Lyons, S.; Meisel, Z.; Montes, F.; Naqvi, F.; Ong, W. J.; Persch, C. F.; Pereira, J.; Schatz, H.; Schmidt, K.

Abstract

Nuclei around the N = 40 “island of inversion” exhibit interesting structure features that have been the focus
of several experimental and theoretical studies. The present work presents the first complete study of the β-decay
feeding intensity distribution and Gamow-Teller distribution for the β decay of 64 Mn to 64 Fe up to ≈ 10 MeV.
The β-decay intensity function was extracted from total absorption spectroscopy measurements made at the
National Superconducting Cyclotron Laboratory with the Summing NaI(Tl) (SuN) detector. The experimental
results are compared to shell model calculations with and without the inclusion of the νg9/2 orbital. From
this comparison it is clear that the νg9/2 orbital is essential for the accurate description of the 64 Fe β-decay
strength above ≈ 3 MeV, emphasizing once again the transitional nature of this nucleus into the N = 40 island
of inversion.

Permalink: https://www.hzdr.de/publications/Publ-40809


Beta-delayed neutron emission of 64Mn, 62Cr, and 65Fe

Ong, W. J.; Schatz, H.; Kravvaris, K.; Ahn, S.; Childers, K.; Crider, B. P.; Dombos, A. C.; Langer, C.; Lewis, R.; Liddick, S. N.; Lyons, S.; Meisel, Z.; Montes, F.; Pereira, J.; Richman, D.; Schmidt, K.; Spyrou, A.

Abstract

The beta-decay properties of nuclei near the second nuclear “island of inversion” around neutron rich nuclei with neutron number 40 are important tests of nuclear structure models and interactions. In particular, the beta-delayed neutron emission branch (Pn), is useful for investigating beta-strength and neutron-gamma competition above the neutron separation energies of the daughter nuclei. We report new constraints for Pn values for three nuclei in the region: 62Cr (Pn<1%), 64Mn (Pn=1.5⁢(6)%), and 65Fe (Pn<1%), measured with the Neutron Emission Ratio Observer (NERO) neutron long counter system and the Beta Counting Station (BCS) at the National Superconducting Cyclotron Laboratory (NSCL). Our results resolve the large discrepancy between previous direct and indirect measurements for 64Mn and confirm the predictions of global theoretical models when a statistical treatment of the gamma and neutron decays of the daughter states is included. We also obtain improved half-lives for 62Cr [206(5) ms] and the short-lived isomer in the 62Fe daughter [112(7) ms] from beta-delayed gamma emission data obtained in the same experiment with the Summing NaI (SuN) total absorption spectrometer. Finally, we use gamma emission data to obtain a new upper limit for the 62Cr beta-decay population of the long-lived isomeric state in 62Mn.

Permalink: https://www.hzdr.de/publications/Publ-40808


Data publication: A multiscale investigation of uranium(VI) interaction with a freshwater diatom species

He, Y.; Sushko, V.; Hübner, R.; Foerstendorf, H.; Steudtner, R.; Raff, J.; Mallet, C.; Le Jeune, A.-H.; Beauger, A.; Breton, V.; Peron, O.; Stumpf, T.; Sachs, S.; Montavon, G.

Abstract

The stored data sets represent the microscopic and spectroscopic data generated at the HZDR that were used for the publication about the interaction of uranium(VI) with a freshwater diatom species.

Keywords: Achnanthidium saprophilum; Bio-association; Co-localization; Infrared spectroscopy; Luminescence spectroscopy; Speciation

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40804


Optimization and Automation of Copper-mediated one-step [18F]SFB synthesis starting from the boronic acid pinacol ester

Laube, M.; Loeser, R.; Kopka, K.; Pietzsch, J.

Abstract

Aim: N-Succinimidyl-4-[18F]fluorobenzoate [18F]SFB is a commonly used active ester suitable for the labeling of peptides and proteins. Radiosynthesis of [18F]SFB has been described by various methods, most often multi-step radiofluorination syntheses. Recently, the copper-mediated radiofluorination starting from boronic acid pinacol ester 1 [1] (Fig. 1) or the tributyl stannyl analog [2] in manual and automated radiosyntheses, respectively, were reported as one-step access to [18F]SFB. To substitute our automated three-step method starting from tert-butyl protected N,N,N-trimethylammoniobenzoic acid ester triflate, we attempted both approaches and detail results of optimization and automation starting from 1 herein.

Materials and methods: Organic syntheses comprised the synthesis of the stannyl-based precursor as described [2] as well as that of 1 starting from commercial 4-carboxy-phenyl boronic acid pinacol ester and N-hydroxysuccinimide using DCC as coupling reagent. Radiosyntheses were optimized regarding base (KHCO3/K3PO4) for QMA conditioning, pre-mix time (0-60 min), concentration (2.5-10 mM precursor and 10-40 mM [Cu(OTf)2(py)4]), reaction temperature (90, 110, 130°C), and solvent (DMF, DMA, DMI) using our recently described microliter-scale radiofluorination approach in HPLC vials [3]. Optimized reaction conditions were transferred to an automated radiosynthesizer (TracerlabFx2N) and purification was performed by semi-preparative HPLC and SPE to obtain [18F]SFB in high chemical and radiochemical purity for further conjugation chemistry.

Results: As a starting point, we envisaged the synthesis of the tributyl stannyl analog as precursor but failed to reproduce the reported synthesis starting from N-succinimidyl 4-iodobenzoate [2]. In comparison, the boronic acid pinacol ester was readily accessable from commercial starting materials in 84-89% yield. The optimized radiosynthesis sequence included elution of [18F]fluoride from a K3PO4-conditioned QMA cartridge with KOTf/K2CO3 in MeCN/H2O, evaporation at 130°C followed by radiofluorination using 10 mM of 1 and 40 mM of [Cu(OTf)2(py)4] in DMI at 90°C for 15 min. Automation furnished [18F]SFB in 13-20% isolated radiochemical yield after 68-83 min (n = 3).

Conclusion: Radiosynthesis of [18F]SFB starting from 1 was successfully optimized and transferred to an automated radiosynthesizer. The method provides the synthon in slightly lower RCY compared to our three-step method but preparation and the reaction sequence is considerable easier, allowing also to use the second reaction vessel of the module for conjugation chemistry which was not possible in the three-step two-pot approach applied before.

Keywords: copper-mediated radiofluorination

Involved research facilities

  • ZRT
  • Open Access Logo Poster
    21st European Symposium on Radiopharmacy and Radiopharmaceuticals, 18.-21.04.2024, Coimbra, Portugal
    DOI: 10.1186/s41181-024-00294-8

Permalink: https://www.hzdr.de/publications/Publ-40803


Data publication: Solutal convection in Na-Zn liquid metal batteries and its influence on self-discharge

Duczek, C.; Weber, N.; Nash, W.; Sarma, M.; Weier, T.

Abstract

Data for numerical results on the investigations presented in the corresponding research article.

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40801


Modelling Mass Transport in NaCl and ZnCl2 Containing Electrolytes

Duczek, C.; Weber, N.; Weier, T.

Abstract

Due to the ongoing energy transition from fossil fuels to renewable energies, the topic of energy storage is more present than ever. Here, liquid metal batteries (LMBs) are one promising option for low-cost stationary storage of electrical energy. The working principle in general is quite simple – the system of liquid metal anode, molten salt electrolyte and liquid metal cathode self-assembles due to density differences and during operation electroactive species migrate from electrode to electrode through the electrolyte. The battery in the present study uses sodium as anode and zinc as cathode material as well
as a two layered molten salt mixture being separated by a diaphragm. Figure 1 shows this setup. Flow phenomena due to the liquid nature of the battery will arise during operation [1]. Most interestingly and very likely to occur in the electrolyte are thermal and solutal convection, which are consequences of unstable density distribution due to species transport and temperature differences. So far, those have mostly been investigated in the cathode of traditional LMBs only [2, 3]. Recently, mass transport in the electrolyte of a LiBi LMB was numerically investigated [4].
For NaZn cells, the electrolyte where two active species – Na + and Zn 2+ – are transported primarily is the most important region to consider. The consequences of the mentioned convection phenomena are improved mixing of the electrolyte and reduced concentration overpotentials, but also self-discharge is promoted by mass transfer. Thus, knowing and understanding the species transport in the electrolyte is a major step in improving cell
performance. Also, a charge-discharge asymmetry for solutal convection will be present during operation. Hence, solutal convection might evolve in the upper part of the electrolyte during charge and at discharge in the lower one. Additionally, the diaphragm influences the species transport and the evolving flow.
When operated above a critical current density, solutal convection can be observed in form of plumes evolving and sinking down/rising up, as it is exemplary shown in Fig. 1.

  • Lecture (Conference)
    The 29th EUCHEM Conference on Molten Salts and Ionic Liquids, 22.-26.04.2024, Santiago de Compostela, Spanien

Permalink: https://www.hzdr.de/publications/Publ-40800


Data publication: Roadmap on Advanced/operando characterisation of solid state materials and devices for energy applications - Positron annihilation spectroscopy

Liedke, M. O.; Menéndez, E.; Keeble, D. J.; Čížek, J.

Abstract

Positron annihilation spectroscopy (PAS) is a precise probe of point defects in bulk and nanomaterials, e.g., thin films. Positrons localize predominantly in the neutral and negatively charged open volume defects, i.e., vacancies and their agglomerations, extended defects, pores. The time to the inevitable annihilation of the positron with electron depends on the local electron density and scales proportionally with the open volume size. In insulators containing pores, Positronium (Ps) formation is enabled, so that the lifetime of the resulting ortho-Ps population again scales proportionally with pore size. Employing mono-energetic positron beams enables the study of near-surface buried defects. Positrons pre-accelerated to a given kinetic energy are implanted into solids following the so-called Makhov distribution [Fig. 1b]. Once localized in a defect, the positron lifespan increases and the overlap of the positron density with the core electron density is reduced. As a consequence, the Doppler shift of annihilation gamma rays becomes smaller. These characteristics are measured using two major techniques, namely positron annihilation lifetime spectroscopy (PALS) and coincidence Doppler broadening spectroscopy (cDBS or cDB-PAS), respectively. The analysis of the positron lifetime spectra [Fig. 2a] enables a decomposition into exponential components characterized by lifetime (ti) and intensity (Ii), which can be translated into defect type/size and concentration. Whereas the shape analysis of the broadened 511 keV annihilation spectrum provides insights to positron annihilation with low momentum valence electrons and high momentum core electrons. The latter determines the local chemical environment of positron annihilation sites (Fig. 2b), which is relevant for characterization of fusion materials. Here we present the research data for figures 1b, 2a, and 2b.

Keywords: functional materials; positron annihilation spectroscopy; operando experiments

Involved research facilities

Related publications

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40799


Ion driven β- to γ-Ga2O3 phase transition and resulting defect microstructure

Liedke, M. O.; Bektas, U.; Liu, H.; Makkonen, I.; Butterling, M.; Hlawacek, G.; Wagner, A.

Abstract

β-Ga2O3 is a novel functional material of an exceptionally wide bandgap (4.7 eV), which provides a route to applications as a semiconductor in power and optoelectronics, as well as batteries. Still, quite challenging is to conserve the monoclinic phase of β-Ga2O3 that undergoes nanostructuring without development of parasitic phase polymorphs. The control over different Ga2O3 crystal phases can be realized using ion irradiation, particularly employing noble gases, like Ne+. In this study, a phase transition from β to γ has been observed as a function of ion fluence and investigated by positron annihilation spectroscopy (PAS). A peculiar evolution of defect microstructure has been captured using Doppler broadening PAS, where an accumulation of defects is observed for a low fluence range, followed by a sudden reduction of defect density in the range of ~1016 ion·cm-2, with further increase for larger fluences. The reduction of defect concentration gives an onset of the transition to the γ-phase. Utilizing the pulsed positron beam at ELBE an estimation of positron lifetimes during the phase transition was possible. At the threshold fluence, positron lifetime raises from a value expected for a Ga vacancy (VGa) in the β-phase [1] to a dimension predicted for VGa in the γ-phase, according to our ab-initio DFT calculations. The γ-phase is characterized by a high level of disordering and no clear free positron state, in contrast to the β-phase, hence the observed drop of positron lifetime for the largest fluence reflects most probably the intrinsic modifications of the disorder magnitude.

[1] A. Karjalainen, V. Prozheeva, K. Simula, I. Makkonen, et al., Phys. Rev. B. 102, 195207 (2020).

Keywords: Ga2O3; β-Ga2O3; γ-Ga2O3; Ga vacancy; positron annihilation lifetime spectroscopy

Involved research facilities

Related publications

  • Lecture (Conference)
    Fall Meeting of the European Materials Research Society (E-MRS), 16.-19.09.2024, Warsaw, Poland

Permalink: https://www.hzdr.de/publications/Publ-40796


Vacancy like defects in Cd3As2

Liedke, M. O.; Rice, A.; Butterling, M.; Hirschmann, E.; Haegel, N. M.; Alberi, K.; Wagner, A.

Abstract

Cd3As2 is a three-dimensional topological semimetal which can be transformed into exotic phases, e.g., Weyl semimetals, topological superconductors, or axion insulators. Using epitaxy provides an avenue for varying and controlling point defects during Cd3As2 growth. The knowledge of vacancy defects is essential for interpretation of electron transport behavior and guides growth efforts to develop materials with low defect concentrations. Point defects in Cd3As2 epilayers grown by molecular beam epitaxy with varying As/Cd flux ratios are probed by
positron annihilation spectroscopy. We show that lower As/Cd flux ratios produce higher concentrations of point defects. Remarkably, the measurements indicate that the average defect size is larger than a monovacancy and vacancy complexes dominate [Rice et al. APL Mater 11, 061109 (2023)]. The evolution of defect microstructure as a function of temperature will be discussed as well.

Keywords: Cd3As2; positron annihilation spectroscopy; topological semimetal; point defects

Involved research facilities

Related publications

  • Lecture (Conference)
    DPG-Frühjahrstagung der Sektion Kondensierte Materie (SKM), 17.-22.03.2024, Berlin, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40795


Positron annihilation spectroscopy: pursuing point defects in superconducting films

Klug, S.; Zubtsovskii, A.; Wenskat, M.; Butterling, M.; Wagner, A.; Liedke, M. O.

Abstract

Positron annihilation spectroscopy (PAS) is a precise probe of point defects in nanomaterials. It enables to
sense defect densities in the range of 10^15 − 10^19 cm^−3. Positrons localize in the neutral and negatively
charged open volume defects, i.e. vacancies and their agglomerations, extended defects or pores. The time
to annihilation of the positron with an electron depends on local electron density and it scales with the open
volume size. The annihilation process itself leads to emission of gamma radiation, which is subsequently
measured. Positrons pre-accelerated to a given kinetic energy can be implanted into solids, allowing depth
profiling. In a defect positron lifetime increases and the energetics of the annihilation photons changes. These
characteristics are measured using two main measurement techniques, namely positron annihilation lifetime
(PALS) and coincidence Doppler broadening spectroscopy (cDBS), respectively. Both techniques are available
at the user facility ELBE (HZDR, Germany). PALS allows to evaluate the defect size and concentration, while
cDBS is sensitiv to the local atomic chemistry.
This contribution discusses the role of defects in superconducting materials, candidates for coatings of SRF
cavities. The advantages of using PAS to evaluate defect concentration and chemistry in Nb have been demonstrated
for vacancy-hydrogen complexes during low temperature baking [1] as well as in case of vacancy kinematics
and evolution of native Nb oxides for baking at larger temperatures [2]. A combination of PAS and
DFT calculations has transformed the experimental results into defect types/sizes and highlighted the role of
vacancy complexes and Nb oxides onto performance of cavities. We will present the most recent evaluation
of defect microstructure in DC- and HiPIMS-sputter deposited Nb, NbN, and NbTiN films.
[1] M. Wenskat et al., Sci. Rep. 10 (2020) 8300
[2] M. Wenskat et al., Phys. Rev. B. 106 (2022) 094516

Keywords: Superconductivity; Magnetron sputtering; Thin films; Positron annihilation spectroscopy; Point defects

Involved research facilities

Related publications

  • Lecture (Conference)
    11th International Workshop on Thin Films and New Ideas for Pushing the Limits of RF Superconductivity - TFSRF2024, 16.-20.09.2024, Gif-sur-Yvette, France

Permalink: https://www.hzdr.de/publications/Publ-40794


On the hydrogen bubble evolution on micro- and macro-electrodes

Rox, H.; Bashkatov, A.; Babich, A.; Krause, L.; Gatter, J.; Yang, X.; Mutschke, G.; Eckert, K.

Abstract

Poster on the hydrogen bubble evolution on micro- and macro-electrodes

Involved research facilities

  • Data Center
  • Poster
    Green Hydrogen Innovation Congress 2024, 29.05.2024, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40793


On the hydrogen bubble evolution on micro- and macro-electrodes

Bashkatov, A.; Babich, A.; Krause, L.; Rox, H.; Yang, X.; Mutschke, G.; Eckert, K.

Abstract

Poster on the hydrogen bubble evolution on micro- and macro-electrodes

Involved research facilities

  • Data Center
  • Poster
    Green Hydrogen Innovation Congress 2022, 02.11.2022, Leipzig, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40792


Pseudo Molecular Doping and Ambipolarity Tuning in Si Junctionless Nanowire Transistors Using Gaseous Nitrogen Dioxide

Vardhan, V.; Biswas, S.; Ghosh, S.; Tsetseris, L.; Ghoshal, T.; Hellebust, S.; Georgiev, Y.; Justin, D. H.

Abstract

Ambipolar transistors facilitate concurrent transport of both positive (holes)
and negative (electrons) charge carriers in the semiconducting channel.
Effective manipulation of conduction symmetry and electrical characteristics in
ambipolar silicon junctionless nanowire transistors (Si-JNTs) is demonstrated
using gaseous nitrogen dioxide (NO2). This involves a dual reaction in both
p- and n-type conduction, resulting in a significant decrease in the current
in n-conduction mode and an increase in the p-conduction mode upon NO2
exposure. Various Si-JNT parameters, including “on”-current (Ion), threshold
voltage (Vth), and mobility (μ) exhibit dynamic changes in both the p- and
n-conduction modes of the ambipolar transistor upon interaction with NO2
(concentration between 2.5 – 50 ppm). Additionally, NO2 exposure to Si-JNTs
with different surface morphologies, that is, unpassivated Si-JNTs with a native
oxide or with a thermally grown oxide (10 nm), show distinct influences on Ion,
Vth, and μ, highlighting the effect of surface oxide on NO2-mediated charge
transfer. Interaction with NO2 alters the carrier concentration in the JNT
channel, with NO2 acting as an electron acceptor and inducing holes, as supported
by Density Functional Theory (DFT) calculations, providing a pathway
for charge transfer and “pseudo” molecular doping in ambipolar Si-JNTs.

Keywords: Ambipolarity Tuning; Junctionless Nanowire Transistors; Nitrogen Dioxide; unpassivated Si-JNTs; Molecular Doping; Gas Sensing

Involved research facilities

Related publications

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40791


Extracting Measurements from (legacy) publications

Steinbach, P.; Gottschall, T.; Niehoff, T.; Ebert, J.; Strube, A.

Abstract

Scientific Publishing has built the basis of knowledge exchange since the inception of the modern scientific method. Papers of last centuries contain uncountable experimental and theoretical findings. When exploring new materials or their facets, it becomes instrumental to extract these information from a myriad of papers. In this work, we present first attempts to extract viable physics information from existing publications using large language models. While the extraction of clearly defined terminology is straight forward, we showcase results with more vague information. We will compare our findings using different input formats and language models such as Mixtral 8x7B. We hope to start a conversation in the community how to bridge the paper-to-data-table gap in our community.

Keywords: machine learning; large language models; retrieval augmented generation

Involved research facilities

  • Data Center
  • Invited lecture (Conferences)
    1st Large Language Models in Physics Symposium, 22.02.2024, Hamburg, Germany

Permalink: https://www.hzdr.de/publications/Publ-40790


Synthesis and Characterization of Homo- and Heteroleptic Neptunium(IV) Heteroarylalkenolate Complexes

Grödler, D.; Kaden, P.; Sperling, J. M.; Rotermund, B. M.; Scheibe, B.; Beck, N. B.; Lichtenberg, A.; Albrecht, T. E.; Mathur, S.; Gericke, R.

Abstract

Heteroleptic An(IV) (An = U, Np) chlorido-ketoenaminate complexes of the type [AnCl₂(TFB-tBuA)₂(THF)] (An-1 type: U-1, Np-1; TFB-tBuA = 4-(tert-butylamino)-1,1,1-trifluorobut-3-en-2-one) and the homoleptic Np(IV) heteroarylalkenolate complexes [Np(PyTFP)₄] (Np-2, PyTFP = 1-(pyridin-2-yl)-3,3,3-trifluoroprop-1-en-2-ol) and [Np(DMOTFP)₄] (Np-3, DMOTFP = 1-(4,5-dimethyloxazol-2-yl)-3,3,3-trifluoroprop-1-en-2-ol) were synthesized and characterized (SC-XRD, NMR, Vis−NIR, MS). While their solid-state structures compare well to those of their uranium analogues, the behavior in solution showed significant differences. The binding motif of the DMOTFP ligand in complex Np-3 can change to form two different complex isomers, as seen by paramagnetic chemical shifts in NMR experiments. Furthermore, the flexibility and the influence of the steric effects at the N-side of the ligands are discussed and compared with its uranium counterpart.

Keywords: actinides; single-crystal X-ray diffraction; neptunium; paramagnetic NMR; ASAP-APCI-MS

Permalink: https://www.hzdr.de/publications/Publ-40789


Ultrasonic measurement to determine temporally and spatially resolved liquid fraction of foam

Emmerich, H.; Knüpfer, L.; Weik, D.; Czarske, J.; Trtik, P.; Eckert, K.; Heitkam, S.

Abstract

In-situ information on foam’s liquid fraction is not accessible with easily appliable measurement systems. We are presenting a novel measurement setup and algorithm to measure foam’s liquid fraction spatially and temporally resolved. As illustrated in Figure 1, we built an ultrasound array (mean frequency 135 kHz), consisting of six ultrasound transducers on one side and two ultrasound transducers on the opposite side of a cylinder filled with liquid foam. Continuous new production and forced drainage of the foam ensured static, homogeneous foam parameters. Electrodes were used alongside with the ultrasonic transducers for calibration. A specifically developed ultrasonic backscatter algorithm was used to determine the local liquid fraction of specified time gates allocated to the corresponding positions within the foam. Already crossed gates were taken into account to amplify the signal of distal gates accordingly. Neutron imaging was performed as a reference. For liquid fractions < 1 % and penetration depth until 9.2 cm, we were able to determine the liquid fraction with an absolute measurement uncertainty of 0.17 10−2 for two spatial dimensions and in time. The allocation was validated with inhomogeneous and dynamic liquid fraction distributions.
In order to conduct a parameter study, we also changed the needle diameters of the air inlet to change the bubble size and adjusted the forced drainage to change the liquid fraction. We were able to verify, that also for ultrasonic wavelength about the size of the bubble diameter, the speed of sound decreases and the attenuation rises, the higher the foam’s liquid fraction and the bigger the bubble diameter (2.6…4.4 mm). Summarizing, we conducted information about acoustic-foam interaction and were able to resolve the liquid fraction in time and space.

Keywords: froth; foam; liquid fraction; bubble size; ultrasound

  • Lecture (Conference)
    15th European Foam Conference (EUFOAM), 30.06.-04.07.2024, Dresden-Rossendorf, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40788


Identification of bubbles in bubbly liquids using non-linear acoustic interaction

Emmerich, H.; Dou, Z.; Weik, D.; Czarske, J.; Tholan, V.; Heitkam, S.; Eckert, K.

Abstract

In multiphase flow processes such as flotation, it is essential to determine air content,
particle content and bubble size independent from one another to save process energy
and increase the flotation grade.
In this work we propose a technique to measure the bubble diameter using non-linear
acoustics (intermodulation) and oscillation. Ultrasound has already shown good results1
in monitoring opaque multiphase processes.
According to Minnaert et al.2 the frequency for the fundamental oscillation mode of a
bubble can be calculated by using the ambient pressure and density of the medium, and
the bubble diameter. Bubble oscillation can be stimulated with that pumping frequency.
Superposing a high probing frequency with the non-linear transfer function of the
oscillating bubbles leads to a mixing of the probing and the pumping frequency. Thus,
by sweeping through possible oscillation frequencies we can analyze at which
frequency the sum and difference of measuring and oscillation frequency appears and
solve the inverse problem to infer the bubble diameter.
For the reflux flotation that gives us certainty if unintentional bubbles or only intentional
particles are present in the measurement region. Regarding research, it can be used to
measure relative bubble size distributions.
To test our method, an own bubble generator (BUG), was used. It was operated with
water with a non-ionic surfactant (20 g/t Methyl-Isobutyl-Carbinol) at an air flux of 1 slpm
and a liquid flux of 20 l/min.
Three ultrasound sensors were implemented in a pipe with 2 cm inner diameter, see
figure 1a. The two high frequency transducers have a mid-frequency at 4.5 MHz. One of
them is used as a transmitter of a continuous wave. The bubbles scatter the wave and
the other transducer records the sound. The third transducer was used in a range of
20…40 kHz to excite the bubbles at resonance.
Our hypothesis was validated when we detected another measurement deflection at a
pumping frequency of 35 kHz, see figure 1b. With the deflections at 4.5 MHz ± 35 kHz
the inverse problem was solved and we can deduce the bubble size. Slightly changed
pumping frequencies lead to a frequency shift and vary in amplitude of the deflections,
enabling a conclusion of the bubble size distribution. In the next step, large quantities of
mineral particles will be added to mimic conditions in a flotation cell.

Keywords: three phase flow; bubbles; ultrasound; oscillation; ultrasonic measurement technique

  • Lecture (Conference)
    Jahrestreffen Dechema Fachgruppen 2024, 20.-21.03.2024, Bremen, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-40787


Data publication: Direct free energy calculation from ab initio path integral Monte Carlo simulations of warm dense matter

Dornheim, T.; Moldabekov, Z.; Schwalbe, S.; Vorberger, J.

Abstract

This repository contains the raw data of all figures shown in the publication "Direct free energy calculation from ab initio path integral Monte Carlo simulations of warm dense matter"; note that the same format and units like in the paper are being used.

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40786


Studying particle entrainment mechanisms using particle-based separation modelling

Hassan, A.; Aparece, M. J.; Rudolph, M.; Pereira, L.

Abstract

Particle entrainment in froth flotation plays a pivotal role in overall process performance and separation efficiency, but modelling its mechanisms remain a significant research challenge. This study aims at the application of those models on a simple model ore comprising a pyrite-quartz system and a complex porphyry copper ore in batch flotation tests. Moreover, the effects of hydrodynamic conditions (impeller tip speed and superficial gas velocity) and reagent concentrations (collector and frother) on entrainment were evaluated, along with the combined effect and interaction of these variables. In the last step, particle-based separation modelling, i.e., logistic regression-based models were trained on particle datasets obtained from 2D-automated mineralogy from complex copper ore flotation to compute recovery probabilities for all particles. Entrainment modelling approaches were applied on individual particles and efforts were made to understand entrainment as a function of process conditions and particulate properties (size, density, shape, overall and surface mineral composition, etc.).

Keywords: Entrainment; automated mineralogy; particle-based separation modelling; true flotation

Involved research facilities

  • Metallurgy Technical Centre
  • Contribution to proceedings
    XXXI IMPC-International Mineral Processing Congress, 29.09.-03.10.2024, Washington D.C., United States of America
    IMPC 2024, 978-0-87335-518-6

Permalink: https://www.hzdr.de/publications/Publ-40785


Data publication: Matlab scripts for PSD measurments and rate spectra analysis

Zhou, W.; Fischer, C.

Abstract

The open datasets provide the Matlab scripts for the calculation of Power Spectra Density and Rate Spectra in the manuscirpt 'How crystal surface reactivity controls the evolution of surface microtopography during dissolution'.

Keywords: PSD analysis; surface analysis; Matlab

Downloads

Permalink: https://www.hzdr.de/publications/Publ-40784


Years: 2024 2023 2022 2021 2020 2019 2018 2017 2016


Pages: [1.] [2.] [3.] [4.] [5.] [6.] [7.] [8.] [9.] [10.] [11.] [12.] [13.] [14.] [15.] [16.] [17.] [18.] [19.] [20.] [21.] [22.] [23.] [24.] [25.] [26.] [27.] [28.] [29.] [30.] [31.] [32.] [33.] [34.] [35.] [36.] [37.] [38.] [39.] [40.] [41.] [42.] [43.] [44.] [45.] [46.] [47.] [48.] [49.] [50.] [51.] [52.] [53.] [54.] [55.] [56.] [57.] [58.] [59.] [60.] [61.] [62.] [63.] [64.] [65.] [66.] [67.] [68.] [69.] [70.] [71.] [72.] [73.] [74.] [75.] [76.] [77.] [78.] [79.] [80.] [81.] [82.] [83.] [84.] [85.] [86.] [87.] [88.] [89.] [90.] [91.] [92.] [93.] [94.] [95.] [96.] [97.] [98.] [99.] [100.] [101.] [102.] [103.] [104.] [105.] [106.] [107.] [108.] [109.] [110.] [111.] [112.] [113.] [114.] [115.] [116.] [117.] [118.] [119.] [120.] [121.] [122.] [123.] [124.] [125.] [126.] [127.] [128.] [129.] [130.] [131.] [132.] [133.] [134.] [135.] [136.] [137.] [138.] [139.] [140.] [141.] [142.] [143.] [144.] [145.] [146.] [147.] [148.] [149.] [150.] [151.] [152.] [153.] [154.] [155.] [156.] [157.] [158.] [159.] [160.] [161.] [162.] [163.] [164.] [165.] [166.] [167.] [168.] [169.] [170.] [171.] [172.] [173.] [174.] [175.] [176.] [177.] [178.] [179.] [180.] [181.] [182.] [183.] [184.] [185.] [186.] [187.] [188.] [189.] [190.] [191.] [192.] [193.] [194.] [195.] [196.] [197.] [198.] [199.] [200.] [201.] [202.] [203.] [204.] [205.] [206.] [207.] [208.] [209.] [210.] [211.] [212.] [213.] [214.] [215.] [216.] [217.] [218.] [219.] [220.] [221.] [222.] [223.] [224.] [225.] [226.] [227.] [228.] [229.] [230.] [231.] [232.] [233.] [234.] [235.] [236.] [237.] [238.] [239.] [240.] [241.] [242.] [243.] [244.] [245.] [246.] [247.] [248.] [249.] [250.] [251.] [252.] [253.] [254.] [255.] [256.] [257.] [258.] [259.] [260.] [261.] [262.] [263.] [264.] [265.] [266.] [267.] [268.] [269.] [270.] [271.] [272.] [273.] [274.] [275.] [276.] [277.] [278.] [279.] [280.] [281.] [282.] [283.] [284.] [285.] [286.] [287.] [288.] [289.] [290.] [291.] [292.] [293.] [294.] [295.] [296.] [297.] [298.] [299.] [300.] [301.] [302.] [303.] [304.] [305.] [306.] [307.] [308.] [309.] [310.] [311.] [312.] [313.] [314.] [315.] [316.] [317.] [318.] [319.] [320.] [321.] [322.] [323.] [324.] [325.] [326.] [327.] [328.] [329.] [330.] [331.] [332.] [333.] [334.] [335.] [336.] [337.] [338.] [339.] [340.] [341.] [342.] [343.] [344.] [345.] [346.] [347.] [348.] [349.] [350.] [351.] [352.] [353.] [354.] [355.] [356.] [357.] [358.] [359.] [360.] [361.] [362.] [363.] [364.] [365.] [366.] [367.] [368.]