Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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41396 Publications

Investigation of Tumor Cells and Receptor-Ligand Simulation Models for the Development of PET Imaging Probes Targeting PSMA and GRPR and a Possible Crosstalk between the Two Receptors

Liolios, C.; Patsis, C.; Lambrinidis, G.; Tzortzini, E.; Roscher, M.; Bauder-Wüst, U.; Kolocouris, A.; Kopka, K.

Prostate-specific membrane antigen (PSMA) and gastrin-releasing peptide receptor (GRPR) have both been used in nuclear medicine as targets for molecular imaging and therapy of prostate (PCa) and breast cancer (BCa). Three bioconjugate probes, the PSMA specific: [68Ga]Ga-1, ((HBED-CC)-Ahx-Lys-NH-CO-NH Glu or PSMA-11), the GRPR specific: [68Ga]Ga-2, ((HBED-CC)-4-amino-1-carboxymethyl piperidine-[D-Phe6, Sta13]BN(6-14), a bombesin (BN) analogue), and 3 (the BN analogue: 4-amino-1-carboxymethyl piperidine-[(R)-Phe6, Sta13]BN(6-14) connected with the fluorescent dye, BDP-FL), were synthesized and tested in vitro with PCa and BCa cell lines, more specifically, with PCa cells, PC-3 and LNCaP, with BCa cells, T47D, MDA-MB-231, and with the in-house created PSMA-overexpressing PC-3(PSMA), T47D(PSMA), and MDA-MB-231(PSMA). In addition, biomolecular simulations were conducted on the association of 1 and 2 with PSMA and GRPR. The PSMA overexpression resulted in an increase of cell-bound radioligand [68Ga]Ga-1 (PSMA) for PCa and BCa cells and also of [68Ga]Ga-2 (GRPR), especially in those cell lines already expressing GRPR. The results were confirmed by fluorescence-activated cell sorting with a PE-labeled PSMA-specific antibody and the fluorescence tracer 3. The docking calculations and molecular dynamics simulations showed how 1 enters the PSMA funnel region and how pharmacophore Glu-urea-Lys interacts with the arginine patch, the S1', and S1 subpockets by forming hydrogen and van der Waals bonds. The chelating moiety of 1, that is, HBED-CC, forms additional stabilizing hydrogen bonding and van der Waals interactions in the arene-binding site. Ligand 2 is diving into the GRPR transmembrane (TM) helical cavity, thereby forming hydrogen bonds through its amidated end, water-mediated hydrogen bonds, and π-π interactions. Our results provide valuable information regarding the molecular mechanisms involved in the interactions of 1 and 2 with PSMA and GRPR, which might be useful for the diagnostic imaging and therapy of PCa and BCa.

Keywords: GRPR; LNCaP; MD simulations; MD-MB231; PC-3; PET imaging; PSMA; T47D; breast cancer; prostate cancer

Permalink: https://www.hzdr.de/publications/Publ-34687
Publ.-Id: 34687


Investigation of Eu3+ uptake and spatial distribution in tobacco BY-2 cells

Klotzsche, M.

Lanthanides have become essential for modern life due to their unique chemical, optical and magnetic properties.[1] On the contrary, their versatility causes an accumulation in soils and plants, thus posing a risk for the health of animals and humans. Therefore, a comprehensive understanding of the transfer and migration behavior of lanthanides into plants is crucial for a reasonable risk assessment.
In this work, suspension cultured cells of Nicotiana tabacum Bright-Yellow 2 (BY-2)[2] have been utilized to investigate the uptake of Eu(III) on a molecular level. The bioassociation of the metal was studied quantitatively by ICP MS upon the exposure to the lanthanide, and qualitatively by time-resolved laser-induced fluorescence spectroscopy (TRLFS) and chemical microscopy with particular focus on the spatial distribution and intracellular speciation of Eu(III).

[1] J.-C. Bünzli, in Encyclopedia of Chemical Technology, Wiley Blackwell, 2013, pp. 1-43.
[2] T. Nagata, Y. Nemoto, S. Hasezawa, International review of cytology 1992, 132, 1-30.

Keywords: Plant cell culture; Tobacco BY-2; Europium; Bioassociation; Speciation; Chemical microscopy; Laser spectroscopy

  • Lecture (Conference)
    ChemTUgether 2022 - Graduate Exchange To Enhance Excellent Research, 13.-14.05.2022, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-34686
Publ.-Id: 34686


Stability of doped zirconia under extreme conditions: towards long-term and secure storage of radioactive waste

Svitlyk, V.; Weiß, S.; Hennig, C.

Extreme temperatures and pressures were applied to systems based on stabilized zirconia, ZrO2, doped with Ce4+ ions as surrogate for tetravalent Actinides in order to conclude on their long term stability in deep geological underground. Both tetragonal and cubic Yttrium-stabilized ZrO2 (YSZ) exhibit excellent phase and structural stabilities up to 1150 K. In addition, incorporated guest Ce4+ did not show any increase in their mobility at elevated temperatures. Application of external pressure did not induce any structural or phase changes in cubic YSZ doped with 5 at.% Ce as well. However, a corresponding tetragonal analogue with lower Yttrium content exhibits a 2nd order phase transition towards higher cubic symmetry around 9 GPa. Remarkably, no discharge of the guest Ce4+ ions was observed throughout the transition and further upon increase in pressure. This together with T-dependent data indicates excellent affinity of guest Ce atoms with the host YSZ matrices. The parent YSZ phases are, therefore, promising candidates as host materials for long term underground immobilization for radiotoxic tetravalent elements like U, Th or Pu.

Related publications

Permalink: https://www.hzdr.de/publications/Publ-34685
Publ.-Id: 34685


Estimation of Dzyaloshinskii-Moriya interaction and domain wall damping in ultrathin nanostripes

Volkov, O.; Pylypovskyi, O.; Kronast, F.; Abert, C.; Oliveros Mata, E. S.; Makushko, P.; Mawass, M.-A.; Kravchuk, V. P.; Sheka, D.; Faßbender, J.; Makarov, D.

Asymmetric ultrathin magnetic thin films represent intriguing materil platforms, which support emerging fundamentals effects, such as skyrmion and topological [1] Hall effects and fast motion of chiral magnetic non-collinear textures [2], that underlie prospective memory and logic devices based on spin-orbit torques. Such asymmetric stacks can provide strong perpendicular magnetic anisotropy and Dzyaloshinskii-Moriya interactions (DMI), which is necessary for the sabilization of chiral non-collinear magnetic textures. As the performance of spin-orbitronic devices is determined by the static and dynamic micromagnetic parameters [3], it is crucial to determine all internal micromagnetic parameters for the particular layer combination and sample geometry. In particular, the speed of a domain wall (DW) based racetrack is determined by the DMI constant, $D$, and the DW damping parameter, $\alpha$. The necessity of having strong DMI requires the utilization of ultrathin magnetic (~1 nm) layers, which implies polycrystalinity and compromized structural quality, that substantially enhances the magnetic damping compared to bulk. Accessing this parameters typically requires dynamic experiments, whose interpretations are cumbersome due to the creep regime.
Here, we present the experimental and theoretical investigation of tilted DWs in perpendicularly magnetized asymmetric //CrOx/Co/Pt layer stacks with the surface-induced DMI. We will discuss two possible theoretical mechanism for the appearance of titled DWs: (I) A unidirectional tilt could appear in equilibrium as a result of the competition between the DMI and additional in-plane easy-axis anisotropy, which breaks the symmetry of the magnetic texture and introduce tilts [4]. (II) A static DW tilt could appear due to the spatial variation of magnetic parameters, which introduce pinning centers for DWs [5]. A moving DW can be trapped in a tilted state after the external driving field is off. Based on these theoretical approaches, we perform a statistical analysis of the DW tilt angles obtained in staticts after the external magnetic field used for the sample demagnetization was off. We found that the second approach confirms the experimental observations and allows to determine self-consistently the range of DW damping parameters and DMI constants for the particular layer stack. Using two reference fields, which provide two characteristic tilt angles, allow us to retrieve the range of DMI strength $D \geq 0.8$ mJ/m2 and DW damping parameters $\alpha \geq 0.1$. The upper limit for the DMI constant agrees with an independent transport-based measurement giving $D=0.90 \pm 0.13$ mJ/m2, which further refines our estimate of the damping parameter $\alpha=0.13 \pm 0.02$. Thus, the combination of the proposed method with standard metrological techniques opens up opportunities for the quantification of both static and dynamic micromagnetic parameters based on static measurements of the DW morphology.
[1] N. Nagaosa and Y. Tokura, “Topological properties and dynamics of magnetic skyrmions”, Nat. Nanotechnol. 8, 899 (2013).
[2] A. Fert, N. Reyren, and V. Cros, “Magnetic skyrmions: advances in physics and potential applications”, Nat. Rev. Mater. 2, 17031 (2017).
[3] C. Garg, S.-H. Yang, T. Phung, A. Pushp and S. S. P. Parkin, “Dramatic influence of curvature of nanowire on chiral domain wall velocity”, Sci. Adv. 3, e1602804 (2017).
[4] O. V. Pylypovskyi, V. P. Kravchuk, O. M. Volkov, J. Fassbender, D. D. Sheka and D. Makarov, “Unidirectional tilt of domain walls in equilibrium in biaxial stripes with Dzyaloshinskii–Moriya interaction”, J. Phys. D: Appl. Phys. 53, 395003 (2020).
[5] O. M. Volkov, F. Kronast, C. Abert, E. Se. Oliveros Mata, T. Kosub, P. Makushko, D. Erb, O. V. Pylypovskyi, M.-A. Mawass, D. Sheka, S. Zhou, J. Fassbender and D. Makarov, “Domain-Wall Damping in Ultrathin Nanostripes with Dzyaloshinskii-Moriya Interaction”, Phys. Rev. Appl. 15, 034038 (2021).

Keywords: Dzyaloshinskii-Moriya interaction; Ultrathin asymmetric magnetic layers; Domain wall

Related publications

  • Contribution to proceedings
    IEEE NAP 2022 Conference, 11.-16.09.2022, Kraków, Poland
    Proceedings of the IEEE NAP 2022 Conference

Permalink: https://www.hzdr.de/publications/Publ-34684
Publ.-Id: 34684


Printed Magnetic Field Sensors: From Wearable Devices To Interactive Surfaces

Oliveros Mata, E. S.; Voigt, C.; Ha, M.; Canon Bermudez, G. S.; Kosub, T.; Mönch, J. I.; Zabila, Y.; Illing, R.; Wang, Y.; Valdez-Garduño, N. M.; Fritsch, M.; Mosch, S.; Kusnezof, M.; Faßbender, J.; Vinnichenko, M.; Makarov, D.

Printing electronics is developing as an on-site fabrication approach to obtaining customized functional devices. [1] In particular, printed devices can be designed to suit
the specifications of each user, e.g. size, location, and functionality. Our research focuses on developing touchless devices that interact via printed magnetic field sensors. Here we will show our approach to fabricating magnetoresistive printable pastes containing magnetosensitive particles embedded in a polymeric binder. The engineering of the printed sensors relies on the properties of the paste fillers, binder, substrate, and processing techniques. The properties of the fillers change the output response of the printed sensors. For example, flake particles showing anisotropic magnetoresistance [2] and giant magnetoresistance [3] have excellent sensitivity below 1 mT making them attractive for wearable and on-skin applications. On the other hand, we studied the capabilities of bismuth-based printed sensors [4] showing non-saturating large magnetoresistance; the output characteristics of these devices made them attractive for wide-range magnetic field sensors. Tuning the mechanical properties of the binder gives special deforming capabilities to
the printed sensors. Polymeric binders used to print our sensors on flexible foils allowed us to laminate our printed systems on objects with complex geometries and even on the
human skin. For instance, we achieved stretchable (100% strain) magnetic field sensors by using a styrene-butadiene-styrene block copolymer as a binder. We demonstrated
that these printed sensors are functional after bending to 16 µm bending radius. [3] We demonstrated the scalability of printing magnetic field sensors using automatized
dispenser printing and laser sintering. This technique offers large-area, affordable, customized fabrication of flexible fully printed magnetic field sensors with minimal material requirements. [4] Such fabrication capabilities open the path for extended interactive smart surfaces and touchless terminal boards. We foresee further developing flexible printed touchless devices in 2D and even 3D printed [5] fully embedded systems for navigation, gaming, personal dosimeters, and health monitoring.
[1] Y. Khan, et al. Adv. Mater. 32, 1905279 (2020)
[2] E.S. Oliveros Mata, et al. Appl. Phys. A 127, 280 (2021)
[3] M. Ha, et al. Adv. Mater. 33, 2005521 (2021)
[4] E.S. Oliveros‐Mata, E. S., C. Voigt, et al. Adv. Mater. Technol. 2200227 (2022)
[5] E.M. Palmero, et al. IEEE Trans. Magn. 55, 1 (2018)

  • Lecture (Conference)
    2022 IEEE 12th International Conference Nanomaterials: Applications & Properties, 11.-16.09.2022, Kraków, Polska

Permalink: https://www.hzdr.de/publications/Publ-34683
Publ.-Id: 34683


Magnetic Electronic Skins For Self-Supervised Origami Soft Actuators

Oliveros Mata, E. S.; Ha, M.; Canon Bermudez, G. S.; Liu, J. A.-C.; Evans, B.; Tracy, J.; Makarov, D.

Soft actuators are coming closer to the capabilities of biological mechanical systems.[1] Biomechanics rely on soft, reconfigurable, and efficient structures that allow the
movement, displacement, and interaction of biological systems with their environment. Among others, magnetic soft actuators excel due to the untethered actuation via
electromagnetic fields.[2] Such electromagnetic actuation can be controlled via permanent magnets or coils. Alternating magnetic fields combined with the smart design
of soft actuators have achieved 100 Hz actuation speeds which are attractive to quickly react and adapt to environmental conditions.[3] Additionally, magnetic origami-like
actuators can be specifically magnetized to achieve more complex shape morphing.[4] To close the loop between the actuation of soft systems and the control of their
movements is needed a suitable sensing unit. Robotic systems are normally integrated with sensing awareness to interact with their surroundings. Flexible sensors
mechanically conformal with soft actuators are still under research development. Here, we show the first adaptation of magnetosensitive skins laminated on magnetically
actuated soft actuators.[5] Ultrathin conformal magnetic field GMR and Hall effect sensors were used to detect the magnetization state, the orientation, and the folding
state of origami-like actuators. The magnetic origami foils were made of NdFeB microparticles in PDMS. We found the best thickness and concentration parameters to
achieve untethered magnetic folds defined on the fly. We demonstrate the synergistic combination of magnetic soft actuators and e-skins allowed self-guided assembly into a
box and boat-like layouts. The assembly process was followed and controlled by the signal recovered from the laminated sensing e-skins. We expect further alike integrations for autonomous remote soft mechatronic systems, where untethered actuation is needed.
[1] A. Miriyev, et al. Nat. Commun. 8, 596 (2017)
[2] S. Wu, et al. Multifunct. Mater. 3, 042003 (2020)
2022 IEEE NAP / Abstract 2
[3] X. Wang, et al. Commun. Matter. 1, 67 (2020)
[4] Y. Kim, et al. Nature. 558, 274 (2018)
[5] M. Ha, et al. Adv. Mater. 33, 2008751 (2021)

  • Lecture (Conference)
    2022 IEEE 12th International Conference Nanomaterials: Applications & Properties, 11.-16.09.2022, Kraków, Poland

Permalink: https://www.hzdr.de/publications/Publ-34682
Publ.-Id: 34682


Geometry-induced magnetic effects in planar curvilinear nanosystems

Yershov, K.; Volkov, O.

Historically, investigation of curvature-induced effects in micromagnetism has started from planar curved ferromagnetic systems, e.g. rings, spirals, curved wires and narrow ribbons. In general, these systems could be considered as quasi one-dimensional magnetic objects, whose parameters change only along the wire while remaining constant in cross section. Thus, in the scope of this chapter much attention is dedicated to the general theoretical toolbox for the description of magnetic effects in flat curved systems without torsion. Here, the theoretical activities on the topic of curvilinear wires are summarized providing a systematic description of various static and dynamic curvature-induced effects in such systems. Also, it is discussed the available methods for the fabrication, characterization, and utilization of flat curved systems for the formation of new artificial chiral nanostructures with defined properties from standard magnetic materials.

Keywords: Curvilinear magnetism; Dzyaloshinskii- Moriya interaction; Nanostructures

Permalink: https://www.hzdr.de/publications/Publ-34681
Publ.-Id: 34681


Magnetic soft actuators: magnetic soft robots from macro- to nanoscale

Canon Bermudez, G. S.; Lopez, M. N.; Evans, B. A.; Yershov, K.; Makarov, D.; Pylypovskyi, O.

In this chapter, we make the very first attempt to apply concepts of curvilinear magnetism to the active research field of magnetic soft actuators and, in particular, magnetic soft robots. Specifically, we describe the interplay between the mechanical and magnetic degrees of freedom in mechanically flexible materials. The discussion starts with the common approach based on the analysis of the balance of magnetic and mechanical forces and torques to describe the actuation behavior and performance of mechanically soft magnetic thin films, wires and ribbons. The framework of curvilinear magnetism is then applied to provide an intuitive physical picture of a complex behavior of actuators possessing a complex magnetic texture.

Keywords: soft robotics; actuation; flexible magnet

  • Book chapter
    Denys Makarov and Denis Sheka: Curvilinear Micromagnetism: from fundamentals to applications, Europe: Springer, 2022
    DOI: 10.1007/978-3-031-09086-8_8

Permalink: https://www.hzdr.de/publications/Publ-34680
Publ.-Id: 34680


Complex-shaped 3D nano-architectures for magnetism and superconductivity

Dobrovolskiy, O. V.; Pylypovskyi, O.; Skoric, L.; Fernandez-Pacheco, A.; van den Berg, A.; Ladak, S.; Huth, M.

This chapter gives an overview of the current state of 3D nanofabrication techniques and perspectives of geometry effects in complex-shaped systems. Various nano-architectures are considered, including nanostructured junctions and magnetic nanowire lattices with frustration, wireframe and mesh-like 3D objects, and 3D systems with non-trivial topology and chirality. In addition to the theoretical background, a large section is devoted to novel fabrication techniques relying upon 3D optical lithography and 3D nanoprinting by focused electron and ion beam-induced deposition. Emphasis is on 3D nano-architectures made from materials exhibiting cooperative ground states such as ferromagnetism and superconductivity.

Keywords: curvilinear magnetism; theory; fabrication; characterization

Permalink: https://www.hzdr.de/publications/Publ-34679
Publ.-Id: 34679


Effects of curvature and torsion on magnetic nanowires

Pylypovskyi, O.; Phatak, C.; Volkov, O.

Here, we consider theoretical description and fabrication of thin wires, which are arranged along space curves. Geometry of these nanoarchitectures is characterized by two functions: curvature and torsion, which determine the modification of magnetic responses. The torsion being the key distinguishing parameter from flat curvilinear wires (discussed in Chapter 1) is in the focus of this chapter. The presented analytical approach to address thin wires of circular cross-section (wires) and rectangular cross-section (thin ribbons) deals with the geometry-induced effects stemming from the symmetric and antisymmetric exchange, as well as symmetries of spin-orbit and spin-transfer torques. Using helix- and helicoid-based samples as a case study, we discuss fundamental features in magnetic textures of geometries with twists in three-dimensional space and compare properties of ferromagnetic samples with antiferromagnetic spin chains. The experimental techniques to develop and characterize ferromagnetic nanowires of arbitrary shape at the nanoscale are described.

Keywords: magnetic nanowire; curvature; torsion; theory; fabrication; characterization

Permalink: https://www.hzdr.de/publications/Publ-34677
Publ.-Id: 34677


00343 Magnetic nanostructures

Makarov, D.; Pylypovskyi, O.

Magnetic nanostructures represent a reach playground for fundamental research in magnetism but also are applied in different areas including but not limited to magnetic data storage, permanent magnets, medicine, printing technologies and deep brain stimulation. This broad range of applications is enabled by the tunability of the composition of magnetic nanoscaled objects, which can consist of magnetic and non-magnetic heterostructures, possess different types of magnetic ordering and be of different geometrical shape. In this Chapter, we review fundamentals of magnetic phenomena in magnetic nanostructures, address fabrication and characterisation approaches as well as discuss on application scenarios. Considering the recent activities, we introduce also curvilinear nanostructures, strain coupled artificial multiferroics as well as magnetic 2D materials and heterostructures of magnetic materials and topological insulators.

Keywords: nanomagnetism; theory; experiment

Permalink: https://www.hzdr.de/publications/Publ-34675
Publ.-Id: 34675


Theory on Tidally Forced Rossby Waves in Solar-Like Stars

Horstmann, G. M.; Mamatsashvili, G.; Giesecke, A.; Stefani, F.

We present a new shallow-water formulation of forced magnetohydrodynamic Ross-
by waves originating in the tachocline of solar-like stars. As a novelty to former descriptions,
we add an external tidal potential to the equations and further include a linear damping law,
allowing us to study wave motions driven by arbitrary tidal forces. The model is applied to the
specific case of our sun, where we consider the action of the tidally dominant planet Jupiter.
We present an explicit analytic solution to this problem, which we finally use to estimate char-
acteristic responding wave amplitudes.

Keywords: Rossby waves; tidal forcing; solar dynamo; tachocline

  • Contribution to proceedings
    The 12th pamir International Conference on Fundamental and Applied MHD, 04.-08.07.2022, Krakow, Poland

Permalink: https://www.hzdr.de/publications/Publ-34674
Publ.-Id: 34674


Flexomagnetism and vertically graded Néel temperature of antiferromagnetic Cr2O3 thin films

Makushko, P.; Kosub, T.; Pylypovskyi, O.; Hedrich, N.; Li, J.; Pashkin, O.; Avdoshenko, S.; Hübner, R.; Ganss, F.; Liedke, M. O.; Butterling, M.; Wagner, A.; Wagner, K.; Shields, B. J.; Lehmann, P.; Veremchuk, I.; Faßbender, J.; Maletinsky, P.; Makarov, D.

Antiferromagnetic insulators are a prospective material science platform for magnonics, spin superfluidity, THz spintronics, and non-volatile data storage. A magnetomechanical coupling in antiferromagnets offers vast advantages in the control and manipulation of the primary order parameter yet remains largely unexplored both fundamentally and technologically. Here, we discover a new member in the family of flexoeffects in thin films of technologically relevant antiferromagnetic Cr2O3. We demonstrate that a gradient of mechanical strain can impact the magnetic phase transition resulting in the distribution of the N ́eel temperature along the thickness of a 50-nm-thick film and induces a sizable flexomagnetic coefficient of about 15 μb/nm2 originating from the inhomogeneous reduction of the antiferromagnetic order parameter. The antiferromagnetic ordering in inhomogeneously strained thin films of Cr2O3 can persist up to 100◦ C, rendering Cr2O3 relevant for industrial electronics applications. The presence of a strain gradient in thin films of Cr2O3 may therefore allow for the realization of reconfigurable antiferromagnetic racetracks, magnonic waveguides and magnon crystals. The presence of a strain gradient in ultrathin films of Cr2O3 enables new fundamental research directions on magnetomechanics and thermodynamics of antiferromagnetic solitons, spin waves and artificial spin ice systems in magnetic materials with continuously graded parameters.

Keywords: antiferromagnetism; flexomagnetism; Cr2O3; Neel temperature; NV magnetometry; magnetotransport

Related publications

Permalink: https://www.hzdr.de/publications/Publ-34673
Publ.-Id: 34673


Current- and field- induced magnetization dynamics and magnetic configurations in cylindrical nanowires

Fernandez Roldan, J. A.

In the last years the take-off of three-dimensional nanomagnetism has brought into scene diverse novel non-trivial magnetic textures that could be of interest for spintronic and nanoelectronics applications [1,2]. Particularly, cylindrical nanowires are fascinating building blocks of nanoarchitectures due to its surface curvature that promotes domain walls that are likely to reach the high velocities required for fast recording technologies like the Bloch Point (BP) domain wall [3-6], and non-trivial magnetic configurations like Skyrmion tubes [7-9]. The challenge in several technologies based on these objects is to achieve the fast controlled propagation of domain walls and tailoring magnetic domain structure. In this talk I will review recent developments in spin-polarized current- and field- magnetization processes in cylindrical nanowires [4,5], and present three-dimensional magnetic configurations that are appealing for the development of advanced technologies.

[1] A. Fernandez-Pacheco et al., Three-dimensional nanomagnetism. Nat. Commun. 8, 15756 (2017)
[2] B. Dieny et al., Opportunities and challenges for spintronics in the microelectronics industry. Nat. Electron. 3, 446–459 (2020).
[3] S. Da Col et al., Observation of Bloch-point domain walls in cylindrical magnetic nanowires, Phys. Rev. B, 89, 180405 (2014).
[4] X.-P. Ma et al., Cherenkov-type three-dimensional breakdown behavior of the Bloch-point domain wall motion in the cylindrical nanowire, Appl. Phys. Lett. 117, 062402 (2020).
[4] J.A. Fernandez-Roldan et al., Electric current and field control of vortex structures in cylindrical magnetic nanowires, Phys. Rev. B 102, 024421 (2020).
[5] M. Schöbitz et al., Fast Domain Wall Motion Governed by Topology and Oersted Fields in Cylindrical Magnetic Nanowires. Phys. Rev. Lett. 123, 217201 (2019).
[6] J. A. Fernandez-Roldan, C. Bran, R. P. del Real, M. Vazquez and O. Chubykalo-Fesenko. Bloch Point propagation in cylindrical nanowires under spin-polarized currents. (Submitted) (2021)
[7] J. A. Fernandez-Roldan et al, Magnetization pinning in modulated nanowires: from topological protection to the “corkscrew” mechanism, Nanoscale 10, 5923 (2018)
[8] J. Garcia et al, Narrow Segment Driven Multistep Magnetization Reversal Process in Sharp Diameter Modulated Fe67Co33 Nanowires, Nanomaterials 2021, 11(11), 3077 (2021).
[9] E. Berganza et al., Evidence of Skyrmion-Tube Mediated Magnetization Reversal in Modulated Nanowires. Materials 14, 5671 (2021).

Keywords: Cylindrical Magnetic Nanowire; magnetic domain wall; magnetic domain; spin-polarized current; Oersted field; skyrmion tube; three-dimensional nanomagnetism

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    Magnetic Resonance Laboratory Seminars (Argentina), 17.05.2022, Bariloche, Rio Negro, Argentina

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Permalink: https://www.hzdr.de/publications/Publ-34672
Publ.-Id: 34672


Treatment planning comparison in the PROTECT-trial randomising proton versus photon beam therapy in oesophageal cancer: results from eight European centres

Hoffmann, L.; Mortensen, H.; Shamshad, M.; Berbee, M.; Bizzocchi, N.; Bütof, R.; Canters, R.; Defraene, G.; Ehmsen, M.; Fiorini, F.; Haustermans, K.; Hulley, R.; Korevaar, E.; Clarke, M.; Makocki, S.; Muijs, C.; Murray, L.; Nicholas, O.; Nordsmark, M.; Radhakrishna, G.; Thomas, M.; Troost, E. G. C.; Vilches-Freixas, G.; Visser, S.; Weber, D.; Møller, D.

Purpose: To compare dose distributions and robustness in treatment plans from eight European centres
in preparation for the European randomized phase-III PROTECT-trial investigating the effect of proton
therapy (PT) versus photon therapy (XT) for oesophageal cancer.
Materials and methods: All centres optimized one PT and one XT nominal plan using delineated 4DCT
scans for four patients receiving 50.4 Gy (RBE) in 28 fractions. Target volume receiving 95% of prescribed
dose (V95%iCTVtotal) should be >99%. Robustness towards setup, range, and respiration was evaluated. The
plans were recalculated on a surveillance 4DCT (sCT) acquired at fraction ten and robustness evaluation
was performed to evaluate the effect of respiration and inter-fractional anatomical changes.
Results: All PT and XT plans complied with V95%iCTVtotal >99% for the nominal plan and V95%iCTVtotal >97%
for all respiratory and robustness scenarios. Lung and heart dose varied considerably between centres for
both modalities. The difference in mean lung dose and mean heart dose between each pair of XT and PT
plans was in median [range] 4.8 Gy [1.1;7.6] and 8.4 Gy [1.9;24.5], respectively. Patients B and C showed
large inter-fractional anatomical changes on sCT. For patient B, the minimum V95%iCTVtotal in the worst-
case robustness scenario was 45% and 94% for XT and PT, respectively. For patient C, the minimum
V95%iCTVtotal was 57% and 72% for XT and PT, respectively. Patient A and D showed minor inter-
fractional changes and the minimum V95%iCTVtotal was >85%.
Conclusion: Large variability in dose to the lungs and heart was observed for both modalities. Inter-
fractional anatomical changes led to larger target dose deterioration for XT than PT plans.

Keywords: Oesophageal cancer; Proton therapy; Intensity modulated radiotherapy; Treatment planning; Respiratory motion; Anatomical changes; Quality assurance; Phase III trial

Permalink: https://www.hzdr.de/publications/Publ-34670
Publ.-Id: 34670


Distinguishing local demagnetization contribution to the magnetization process in multisegmented nanowires

Marqués Marchán, J.; Fernandez Roldan, J. A.; Bran, C.; Puttock, R.; Barton, C.; Moreno, J. A.; Kösel, J.; Vazquez, M.; Kazakova, O.; Chubykalo-Fesenko, O.; Asenjo, A.

Cylindrical magnetic nanowires are promising materials with prospects to be used in a wide range of applications. The versatility of these nanostructures is based on the tunability of their magnetic properties by the appropriate selection of the composition and morphology. In addition, stochastic behaviour has attracted attention for the development of neuromorphic devices relying on probabilistic magnetization switching. Here, we present a study of the magnetization reversal process in multisegmented CoNi/Cu nanowires. Non-standard 2D magnetic maps, recorded under in-plane magnetic field produces datasets which are correlated with the magnetoresistance measurements and micromagnetic simulations. From this, the contribution of the individual segments to the demagnetization process can be distinguished. The results show that the magnetization reversal in these nanowires does not occur through a single Barkhausen jump but rather by multi-step switching, as individual CoNi segments in the NW undergo magnetization reversal. The existence of vortex states is confirmed by their footprint in the magnetoresistance and 2D MFM maps. In addition, the stochasticity of the magnetization reversal is analysed. On the one hand, we observe different switching fields among the segments due to a slight variation in geometrical parameters or magnetic anisotropy. On the other hand, the stochasticity is observed in a series of repetitions of the magnetization reversal processes for the same NW under the same conditions.

Keywords: magnetic nanowires; magnetization reversal processes; magnetoresistance; Magnetic Force Microscopy (MFM); CoNi

Related publications

Permalink: https://www.hzdr.de/publications/Publ-34669
Publ.-Id: 34669


Three-dimensional antiferromagnetic architectures

Pylypovskyi, O.

Emergent geometry-driven responses in curvilinear antiferromagnets offer new possibilities to tailor chiral and anisotropic properties of the ground state and non-collinear textures. This includes a possibility to tailor weak ferromagnetism and Dzyaloshinskii-Moriya interaction by means of selection of sample’s shape.

Keywords: antiferromagnet; curvilinear nanostructure

  • Invited lecture (Conferences)
    META 2022, the 12th International Conference on Metamaterials, Photonic Crystals and Plasmonics, 19.-22.07.2022, Torremolinos, Spain

Permalink: https://www.hzdr.de/publications/Publ-34668
Publ.-Id: 34668


Curvilinear antiferromagnets for spintronics applications

Pylypovskyi, O.

Geometry-driven effects in curvilinear magnets provide an effective way to tailor functionality of magnetic nanoarchitectures. Antiferromagnets are perspective materials for novel spintronic devices. In scope of the field of curvilinear magnetism, there is a possibility to tune their chiral, anisotropic and weakly ferromagnetic responses.

Keywords: antiferromagnet; curvilinear nanostructure

  • Invited lecture (Conferences)
    IEEE nano, 04.-08.07.2022, Palma de Mallorka, Spain

Permalink: https://www.hzdr.de/publications/Publ-34667
Publ.-Id: 34667


Curvature-induced Local and Nonlocal Chiral Effects in Curvilinear Ferromagnetic Shells and Wires

Pylypovskyi, O.; Volkov, O.; Sheka, D.; Kakay, A.; Kravchuk, V.; Landeros, P.; Kronast, F.; Mönch, J. I.; Mawass, M.-A.; Saxena, A.; Faßbender, J.; Makarov, D.

Conventional magnetic nanoscale devices are based on planar thin films and straight racetracks hosting magnetic topological solitons. Recent progress in fabrication and characterization methods allows to realise and study of complex-shaped planar and three-dimensional (3D) architectures. In the planar case, boundaries of nanodots lead to the formation of inhomogeneous textures, such as vortices and antivortices. In 3D, the magnetostatic interaction favours a spatially inhomogeneous shape anisotropy, which acts as easy-axis anisotropy along wires or hard axis of anisotropy perpendicular to the film surface. These interactions track the sample geometry and enable curvature-induced symmetry-breaking effects, such as topology-induced magnetization patterning and emergent anisotropic and chiral responses of the Dzyaloshinskii-Moriya interaction (DMI) type [1,2].

Curvature-induced magnetic responses can be classified as being local or nonlocal. In ferromagnets, local effects stem from the exchange interaction and DMI. The curvature-induced DMI originates from exchange: it is linear in curvatures and has the symmetry of the interfacial DMI. Its strength can be comparable with typical values of the intrinsic DMI. This is experimentally confirmed by the stabilization of chiral domain walls (CDW) on the apex of a Permalloy parabola-shaped stripe [3]. The strength of the CDW depinning field gives an estimation for the curvature-induced DMI constant and can be tuned by the geometry. In contrast to curvature itself, also curvature gradients offer a possibility to pin CDW, which was studied with an example of a circular indentation with a conic cross-section profile. This geometry supports circular CDWs described by the forced skyrmion equation, where the effective force acts as the stabilizing factor for large-radius skyrmion and skyrmionium states [4].

The magnetostatic interaction is a source of novel curvature-induced chiral effects, which are essentially nonlocal, in contrast to the conventional DMI [5]. The effect emerges in shells with non-zero mean curvature due to the non-equivalence between the top and bottom surfaces of a geometrically curved shell. It is possible to show that the analysis of nonlocal effects in curvilinear shells can be more intuitive with a split of a conventional volume magnetostatic charge into two terms: (i) tangential charge, governed by the tangent to the sample's surface, and (ii) geometrical charge, given by the normal component of magnetization and the mean curvature. In addition to the shape anisotropy (local effect), four additional nonlocal terms appear, determined by the surface curvature. Three of them are zero for any magnetic texture in shells with the geometry of minimal surfaces. The fourth term becomes zero only for the special symmetries of magnetic textures.

The impact of local and nonlocal chiral effects on magnetic textures in curvilinear architectures will be discussed in this presentation.

Keywords: ferromagnetism; curvilinear shell

  • Lecture (Conference)
    IEEE NAP 2022, 12th International Conference Nanomaterials: Applications & Properties, 11.-16.09.2022, Krakov, Poland

Permalink: https://www.hzdr.de/publications/Publ-34666
Publ.-Id: 34666


Chiral Effects in Curvilinear 1D Antiferromagnets

Pylypovskyi, O.; Kononenko, D.; Borysenko, Y.; Tomilo, A.; Yershov, K.; Roessler, U. K.; Faßbender, J.; van den Brink, J.; Sheka, D.; Makarov, D.

Spin-orbit phenomena enable new ways to manipulate magnetic ordering in low dimensional magnetism. In this respect, materials with antiferromagnetic (AFM) coupling attract significant attention providing higher eigenfrequencies, a rich diversity of material properties and perspectives of spatial scaling due to the absence of significant stray fields. Tailoring the geometry of AFM thin films and nanowires in planar or 3D architectures provides a possibility for changing magnetic responses by means of shape of the magnet [1,2].

In this presentation, we will discuss the recently discovered chiral and anisotropic effects peculiar for curvilinear 1D antiferromagnetic spin chains.

A spin chain arranged along a space curve is a prototypical example of a curvilinear AFM whose shape is characterized by the curvature and torsion. In the absence of intrinsic anisotropy, the dipolar interaction renders the tangential direction as the hard axis of the anisotropy [3]. The competition of this geometry-tracking interaction with the nearest-neighbor exchange leads to the emergence of additional anisotropic and chiral energy terms, whose coefficients are determined by the curvature and torsion. The geometry-induced anisotropy is of easy-axis type and determines the direction of the AFM order parameter within the easy-plane enabled by the dipolar interaction. The geometry-induced inhomogeneous Dzyaloshinskii-Moriya interaction (DMI) renders the curvilinear spin chain acting as a chiral helimagnet. The latter leads to the geometrically-driven helimagnetic phase transition in helix-shaped AFM spin chains [3].

A local variation of the anisotropy axis can result in the non-collinearity of the neighboring spins in curvilinear spin chains. 1D AFMs exhibit the parity-breaking effect, which forbids exchanging sublattices once they are selected. This leads to the emergent magnetization at non-collinear AFM textures Therefore, in any spin chain arranged along a space curve, there is a weak ferromagnetism proportional to the curvature and torsion of the curve [4].

Spin chains arranged on a planar surface have the only ground state along the binormal direction [3]. In presence of an external magnetic field, their spin-flop state is dependent on geometrical parameters. The spin-reorientation transition is followed by the canted state for small enough rings due to the exchange-driven DMI. Furthermore, we will show that the curvature-induced DMI results in the hybridization of spin wave modes and enables a geometrically-driven local minimum of the low frequency branch, which opens exciting perspectives to study long-lived collective magnon states in AFMs [3]. This positions curvilinear 1D antiferromagnets as a novel platform for the realization of geometrically tunable chiral antiferromagnets for antiferromagnetic spinorbitronics and fundamental discoveries in the formation of coherent magnon condensates in the momentum space.

Keywords: spin chain; curvature; torsion; antiferromagnetism

  • Lecture (Conference)
    IEEE NAP 2022, 12th International Conference Nanomaterials: Applications & Properties, 11.-16.09.2022, Krakov, Poland

Permalink: https://www.hzdr.de/publications/Publ-34665
Publ.-Id: 34665


Magnetic composites: from printed magnetoelectronics to smart magnetic soft robots

Makarov, D.

In this presentation, we will review our activities on the realization of printed magnetic field sensors and magnetic soft robots, which are controlled by highly flexible magnetic field sensors.

Keywords: flexible magnetic field sensors; printable magnetic field sensors; soft robots

Related publications

  • Invited lecture (Conferences)
    MRS Fall meeting, 27.11.-02.12.2022, Boston, USA

Permalink: https://www.hzdr.de/publications/Publ-34664
Publ.-Id: 34664


Curvature effects in curvilinear and 3D low dimensional magnetic architectures

Makarov, D.

In this talk, we will review current activities in the realization of geometrically curved and 3D magnetic thin film and nanowires.

Keywords: curvature effects in magnetism; curvilinear magnetism

Related publications

  • Invited lecture (Conferences)
    8th Spanish Workshop in Nanolithography, Nanolito 2022, 26.-28.10.2022, Valencia, Spain

Permalink: https://www.hzdr.de/publications/Publ-34663
Publ.-Id: 34663


Magnetosensitive e-skins and stretchable giant magnetoresistive sensors

Makarov, D.

In this presentation, we will focus on the application oriented research related to curvilinear magnetism. We will cover applications of skin conformal magnetic field sensors for human-machine interfaces and soft robotics.

Keywords: flexible magnetic field sensors; printable magnetic field sensors

Related publications

  • Invited lecture (Conferences)
    conference organized in the frame of the Innovative Training Network "Magnetism and the effect of Electric Field” (MagnEFi), 10.-14.10.2022, Crete, Greece

Permalink: https://www.hzdr.de/publications/Publ-34662
Publ.-Id: 34662


Curvilinear magnetism: fundamentals and applications

Makarov, D.

In this talk, we will review our activities on curvilinear magnetism and related application concepts of skin-conformal magnetic field sensors.

Keywords: curvature effects in magnetism; flexible magnetic field sensors; printed magnetic field sensors

Related publications

  • Invited lecture (Conferences)
    2022 IEEE 12th International Conference Nanomaterials: Applications & Properties, 11.-16.09.2022, Krakow, Poland

Permalink: https://www.hzdr.de/publications/Publ-34661
Publ.-Id: 34661


Flexible und druckbare Low-Power-Magnetfeldsensoren

Makarov, D.

In this talk, we will review our activities on the realization of flexible and printed magnetic field sensors.

Keywords: flexible magnetic field sensors; printable magnetic field sensors

Related publications

  • Invited lecture (Conferences)
    11. GMM-Fachtagung Energieautonome Sensorsysteme (EASS), 05.-06.07.2022, Erfurt, Germany

Permalink: https://www.hzdr.de/publications/Publ-34660
Publ.-Id: 34660


Geometrically curved and skin-conformal magnetoelectronics

Makarov, D.

Conventional magnetic field sensors are fabricated on flat substrates and are rigid. Extending 2D structures into 3D space relying on the flexible electronics approaches allows to enrich conventional or to launch novel functionalities of spintronic-based devices by tailoring geometrical curvature and 3D shape. Here, we will review fundamentals of 3D curved magnetic thin films [1] and primarily focus on their application potential for eMobility, consumer electronics, virtual and augmented reality appliances. The technology platform relies on high-performance magnetoresistive and Hall effect sensors deposited or printed on ultrathin polymeric foils. These skin conformal flexible and printable magnetosensitive elements enable touchless interactivity with our surroundings based on the interaction with magnetic fields [2], which is relevant for electronics skins [3,4], smart wearables [5,6], soft robotics [7] and human-machine interfaces [3-6,8]. In this talk, recent fundamental and technological advancements on flexible magnetoelectronics will be reviewed.

[1] D. Makarov et al., “New Dimension in Magnetism and Superconductivity: 3D and Curvilinear Nanoarchitectures”, Adv. Mater. 34, 2101758 (2022).
[2] G. S. Canon Bermudez et al., “Magnetosensitive E-Skins for Interactive Devices”, Adv. Funct. Mater. 31, 2007788 (2021).
[3] G. S. Canon Bermudez et al., “Electronic-skin compasses for geomagnetic field driven artificial magnetoreception and interactive electronics”, Nature Electronics 1, 589 (2018).
[4] M. Ha et al., “Printable and Stretchable Giant Magnetoresistive Sensors for Highly Compliant and Skin-Conformal Electronics”, Adv. Mater. 33, 2005521 (2021).
[5] P. Makushko et al., “Flexible Magnetoreceptor with Tunable Intrinsic Logic for On-Skin Touchless Human-Machine Interfaces”, Adv. Funct. Mater. 31, 2101089 (2021).
[6] G. S. Canon Bermudez et al., “Magnetosensitive e-skins with directional perception for augmented reality”, Science Advances 4, eaao2623 (2018).
[7] M. Ha et al., “Reconfigurable Magnetic Origami Actuators with On-Board Sensing for Guided Assembly”, Adv. Mater. 33, 2008751 (2021).
[8] J. Ge et al., “A bimodal soft electronic skin for tactile and touchless interaction in real time”, Nature Communications 10, 4405 (2019).

Keywords: curvature effects in magnetism; flexible magnetic field sensors

Related publications

  • Invited lecture (Conferences)
    2022 IEEE 22nd International Conference on Nanotechnology (NANO), 04.-08.07.2022, Palma de Mallorca, Spain

Permalink: https://www.hzdr.de/publications/Publ-34659
Publ.-Id: 34659


Magnetoelectric antiferromagnet Cr2O3 for spinorbitronic applications

Makarov, D.

In this presentation, we reviewed our recent activities on the fabrication and characterization of thin film and SPS-sintered Cr2O3 samples for MRAM and domain wall based memory applications.

Keywords: antiferromagnetic spintronics; Cr2O3 thin films

Related publications

  • Lecture (others)
    Seminar at the University of Leipzig, Fakultät für Physik und Geowissenschaften, Felix-Bloch-Institut für Festkörperphysik, 11.05.2022, Leipzig, Germany

Permalink: https://www.hzdr.de/publications/Publ-34658
Publ.-Id: 34658


FlexiSens: 
smart magnetic field sensor technologies

Makarov, D.

In this presentation, we reviewed the topic of the cooperation between the HZDR and scia Systems GmbH. The topic concerns realization of flexible and printed magnetic field sensors.

Keywords: flexible magnetic field sensors; printable magnetic field sensors

Related publications

  • Invited lecture (Conferences)
    Annual workshop for partners of scia Systems GmbH, 16.03.2022, Chemnitz, Germany

Permalink: https://www.hzdr.de/publications/Publ-34657
Publ.-Id: 34657


Super-SIMS at DREAMS: Status of a unique and complex endeavour

Rugel, G.; Ziegenrücker, R.; Koll, D.; Lachner, J.; Noga, P.; Vivo Vilches, C.; Renno, A.; Wallner, A.; Wiedenbeck, M.

At the DREAMS (DREsden AMS) facility we are implementing a so-called Super-SIMS (SIMS = Secondary Ion Mass Spectrometry) device, which combines the micron-scale spatial resolution of a commercial SIMS (CAMECA IMS 7f-auto) with the high selectivity through molecule suppression by AMS. We have demonstrated high transmission for major element ions including silicon, fluorine and iodine, however the lack of well characterized calibration materials makes the quantification of trace and ultra-elements difficult. Measurements of P in Si show the linearity of the instrument’s relative sensitivity factor over more than three orders of magnitude, and measurements of the isotopic ratio of bromine in ZnS document the reliability of our approach. The goal of the DREAMS Super-SIMS project is to provide quantitative concentration data of ultra-trace elements in geological samples in the context of resource technology.

Keywords: accelerator mass spectrometry; SIMS; trace elements

Related publications

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Permalink: https://www.hzdr.de/publications/Publ-34656
Publ.-Id: 34656


Investigation of radiotracer metabolic stability in vitro with CYP-overexpressing hepatoma cell lines

Lemm, S.; Köhler, S.; Wodtke, R.; Jung, F.; Küpper, J.-H.; Pietzsch, J.; Laube, M.

The characterization of novel radiotracers toward their metabolic stability is an essential part for their development. While in vitro methods such as liver microsome assays or ex vivo blood or tissue samples provide information on overall stability, little or no information is obtained on cytochrome P450 (CYP) enzyme and isoform-specific contribution to the metabolic fate of individual radiotracers. Herein, we investigated recently established CYP-overexpressing hepatoblastoma cell lines (HepG2) for their suitability to study the metabolic stability of radiotracers in general and to gain insight into CYP isoform specificity. Wild-type HepG2 and CYP1A2-, CYP2C19-, and CYP3A4-overexpressing HepG2 cells were incubated with radiotracers and metabolic turnover was analyzed. The optimized protocol, covering cell seeding in 96-well plates and analysis of supernatant by radio-thin-layer-chromatography for higher throughput, was transferred to the evaluation of three 18F-labeled celecoxib-derived cyclooxygenase-2 inhibitors (coxibs). These investigations revealed time-dependent degradation of the intact radiotracers as well as CYP isoform- and substrate-specific differences in their metabolic profiles. HepG2 CYP2C19 proved to be the cell line showing the highest metabolic turnover for each radiotracer studied here. Comparison with human and murine liver microsome assays showed good agreement to the human metabolite profile obtained by the HepG2 cell lines. Therefore, CYP-overexpressing HepG2 cells provide a good complement for assessing the metabolic stability of radiotracers and allow the analysis of the CYP isoform-specific contribution to the overall radiotracer metabolism.

Keywords: cytochrome P450 enzymes; cyclooxygenase-2 inhibitors (coxibs); drug testing models; HepG2 cells; liver microsome assay; mass spectrometry; metabolic radiotracer stability assay; model reliability; radio-thin-layer-chromatography (radio-TLC); pharmacokinetics

Permalink: https://www.hzdr.de/publications/Publ-34655
Publ.-Id: 34655


Simulation of liquid waves with flow reversal in stratified counter-current flow with a hybrid two-fluid model

Tekavcic, M.; Meller, R.; Krull, B.; Schlegel, F.

Processes involving gas and liquid flows are important for reliable, efficient and safe operation of many industrial applications, such as electricity generation in nuclear power plants. Many different two-phase flow patterns can appear in these systems, with a wide range of scales considering both interfacial and turbulent structures. Stratified flow, i.e. phases being separated with a smooth or wavy interface, is one of the most important regimes for safety analyses.

The present paper presents simulations of an isothermal stratified counter-current flow of air and water in a rectangular channel of the WENKA experiment (Stäbler, T.D, 2007, PhD Thesis, Univ. Stuttgart). The partial flow reversal regime with liquid surface waves was considered. A hybrid two-fluid model, featuring consistent momentum interpolation numerical scheme, partial elimination algorithm to handle strong drag coupling between phases, and interface sharpening method, was used to resolve the air-water interface. The Unsteady Reynolds Averaged Navier-Stokes (URANS) approach with the k-ω SST (Shear Stress Transport) model and interface turbulence damping was used to model the turbulent stratified flow with wavy surface. Simulations were performed with the open source C++ library OpenFOAM. Results are validated with experimental data for the height of liquid surface, profiles of velocity and turbulent kinetic energy, and the amount of reversed liquid flow.

  • Poster
    31st International Conference Nuclear Energy for New Europe (NENE 2022), 12.-15.09.2022, Portoroz, Solvenien
  • Contribution to proceedings
    31st International Conference Nuclear Energy for New Europe, 12.-15.09.2022, Portoroz, Solvenien
    Proceedings of the 31st International Conference Nuclear Energy for New Europe

Permalink: https://www.hzdr.de/publications/Publ-34654
Publ.-Id: 34654


Nuclear Safety Research with Open Source CFD Software

Schlegel, F.

During the last years, open source software (OSS) has become more and more popular in academia and industry. For academia in particular, transparency and reproducibility of results according to the FAIR principles is a fundamental requirement for good scientific work. Beside such considerations, OSS has several advantages over commercial software, e.g. the availability of the source code, transparency and reliability of the implemented algorithms, flexibility for own implementations and developments, long-term availability, independence from commercial interests of software manufactures, license models that allow easy collaborations and much more. However, OSS also has disadvantages, which limits the applicability, e.g., often brief documentation, requires high level programming knowledge, upstream contributions require high coding and software design standard, discussions in the community can be very time consuming, many open source licenses cause conflicts with other commercial software packages or national security aspects, and often a sufficient quality assurance is not available.

State-of-the-art for software developments follow nowadays an agile development strategy, which is based on the release of frequent and small changes instead of a long-term milestone driven development. Those frequent commits (modifications) require a high level of automation, unit and integration tests for quality assurance, version control, code style checking, automated packaging and deployment and automated documentation. Those tools can be utilized for a sustainable and efficient development of OSS.

Computational Fluid Dynamics (CFD) is a highly specialized field and is characterized by a vast complexity of the underlying physics and equation. In this field, OpenFOAM1 established itself as the leading open source software package for numerical simulations that owns today a significant share of the market. The software together with the source code is provided by the OpenFOAM Foundation, which ensures robustness, functionality, usability, extensibility and accessibility of OpenFOAM. However, OpenFOAM yet covers not all functionality required for nuclear safety research, and a lot of research and development work is done in this regard. Three years ago, the German CFD Network for Nuclear Safety Research selected OpenFOAM as reference software for containment and reactor coolant system (RCS) related topics. A key point associated with selection of OSS was the need to establish a coordinator, which ensures efficient and sustainable developments in the long term.

HZDR has a long experience in nuclear reactor thermal hydraulics and multiphase CFD, e.g., we have developed an automated scientific workflow based on Snakemake2. HZDR is also an active contributor to the OpenFOAM Foundation release and member of the German CFD Network for Nuclear Safety Research. As a member of the Helmholtz Society, HZDR has access to the Helmholtz Cloud Services3, which provide an excellent environment for agile software development (Gitlab, Mattermost, a.s.o.). Due to this expertise, HZDR was selected as coordinator and maintainer for the OpenFOAM_RCS4 project, funded by German Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection. Within the OpenFOAM_RCS project, HZDR will provide a common platform for nuclear safety research with respect to reactor coolant systems in Germany. The platform includes a repository for software code, a repository for restricted simulation setups, version control, automated testing with pipelines, validation tests and reports for new OpenFOAM version, and documentation. A key thing of the project is also the intensive collaboration with the OpenFOAM core developers (including some funding) for discussion of APIs, core maintenance, and future developments of OpenFOAM.

The lecture will present a comprehensive discussion of the pros and cons of OSS with a special focus on OpenFOAM and why this is a good choice as reference software. It will also show one way that is established and further developed within the OpenFOAM_RCS project to work as backend developer of a large OSS software project like OpenFOAM, and how to overcome the limitations and ensure sustainability of the additional developments. The lecture will discuss briefly the status of the OpenFOAM_RCS project and the planned applications for the next years.

  • Lecture (Conference)
    Advances in Thermal Hydraulics (ATH 2022), 12.-16.06.2022, Anaheim, USA

Permalink: https://www.hzdr.de/publications/Publ-34653
Publ.-Id: 34653


Magnetic control of mass transfer and convection in electrochemical processes

Weier, T.; Mutschke, G.

Outside the classical domains of magnetohydrodynamics, plasmas and
liquid metals, the action of electromagnetic forces can be observed as
well in electrolytes. The talk will start with examples on the control
of flat plate boundary layers and separated flows and discuss their
effectiveness and efficiency. Stationary as well as periodic Lorentz
forces are thematized in this context and proof to be a versatile tool
for research while high energy demand limits their applicability for
naval applications. Switching the context to electrochemical
processes, where an electrical current is inherently present,
alleviates the question of energy demand and opens-up a large field of
additional topics: Improved mass transfer can be used to increase the
limiting current density and thereby the space-time yield of
processes. Efficiency of water electrolyzers benefits from accelerated
removal of bubbles from the electrodes. Magnetic gradient forces can
assist in the build-up of nano-structured ferromagnetic layers using
comparably cheap electrochemical technology.

Keywords: magnetohydrodynamics; magnetoelectrochemistry; Lorentz force; active flow control; Particle Image Velocimetry; Finite Time Lyapunov Exponents; Proper Orthogonal Decomposition; Lagrangian Coherent Structures

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    School of Magneto-Hydro-Dynamics, 21.04.-26.05.2022, Cagliari, Italien

Permalink: https://www.hzdr.de/publications/Publ-34652
Publ.-Id: 34652


Data publication: Unusual dynamics of the ferroelectric phase transition in K1−xLixTaO3 crystals

Nuzhnyy, D.; Bovtun, V.; Buixaderas, E.; Petzelt, J.; Savinov, M.; Kempa, M.; Paściak, M.; Rafalovskyi, I.; Chelod Paingad, V.; Kužel, P.; Kamba, S.; Repček, D.; Pashkin, O.; Trepakov, V. A.; Trybuła, Z.

SHG temperature dependence and dielectric spectroscopy data on KLT measured by A. Pashkin

Keywords: second harmonic generation; THz spectroscopy

Related publications

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Permalink: https://www.hzdr.de/publications/Publ-34651
Publ.-Id: 34651


Preparation of HOPO-containing lariate ethers based on the diaza-18-crown-6 scaffold

Paßler, F.; Belke, L.; Reissig, F.; Kopka, K.; Mamat, C.

Cyclic and acyclic ligands containing the hydroxypyridinone (HOPO) moiety as donor group are known as strong coordinating compounds for a wide variety of metal ions. Based on the diaza-crown[18]ether Kryptofix K22, five different tendentate ligands were prepared using 1,2-HOPO, 1,2,3-HOPO and 2,3-Me-HOPO as additional binding moieties. The diaza-crown ether basic skeleton was furnished with two primary amine functions and subsequently reacted with the respective HOPO acids or the HOPO acid chlorides to obtain the desired HOPO derivatives in two synthesis steps after final deprotection. All compounds were evidenced by NMR and MS analyses.

Keywords: HOPO; complexation; multidentate ligand; diazacrown ether

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  • Secondary publication expected from 14.03.2025

Permalink: https://www.hzdr.de/publications/Publ-34650
Publ.-Id: 34650


Influence of surface cleaning on quantum efficiency, lifetime and surface morphology of p-GaN:Cs photocathodes

Schaber, J.; Xiang, R.; Teichert, J.; Arnold, A.; Murcek, P.; Zwartek, P.; Ryzhov, A.; Ma, S.; Gatzmaga, S.; Michel, P.; Gaponik, N.

Accelerator scientists have high demands on photocathodes possessing high quantum efficiency (QE) and long operational lifetime. p-GaN, as a new photocathode type, gained recently more and more interest because of its ability to form a negative electron affinity (NEA) surface. Being activated with a thin layer of cesium, p-GaN:Cs photocathodes promise higher QE and better stability than the known photocathodes.
In our study, p-GaN samples grown on sapphire or silicon were wet chemically cleaned and transferred into an ultra-high vacuum (UHV) chamber, where they underwent a subsequent thermal cleaning. The cleaned p-GaN samples were activated with cesium to obtain p-GaN:Cs photocathodes and their performance was monitored in respect to their quality, especially their QE and storage lifetime. The surface topography and morphology were examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM) in combination with energy dispersive x-ray (EDX) spectroscopy. We have shown that p-GaN could be efficiently reactivated with cesium for several times.
This paper compares systematically the influence of wet chemical cleaning as well as thermal cleaning at various temperatures on the QE, storage lifetime and surface morphology of p-GaN. As expected, the cleaning influences strongly the cathodes’ quality. We show that high QE and long storage lifetime are achievable at lower cleaning temperatures in our UHV chamber.

Keywords: p-GaN; UV-photocathode; quantum efficiency; surface cleaning; surface morphology

Related publications

Permalink: https://www.hzdr.de/publications/Publ-34646
Publ.-Id: 34646


Influence of Muscovite (001) Surface Sites on Europium Adsorption

Schabernack, J.; Faria Oliveira, A.; Heine, T.; Fischer, C.

A key problem for the long-term safety of nuclear waste repositories is radionuclide migration in the geosphere. The adsorption of radionuclides onto mineral surfaces of the surrounding host rock can provide an important mechanism to retard or prevent migration from the repository to the biosphere. Due to the strong sorption potential of clay minerals, clay rock formations such as the Opalinus Clay are being considered as potential sites for nuclear waste repositories. Phyllosilicates, such as clay minerals or mica, have shown a high affinity for the adsorption of various radionuclides in several experimental studies. In natural environments, mineral surfaces are exposed to reactions (e.g., dissolution) over long periods. These processes can lead to an alteration of the surface nanotopography, thereby affecting the adsorption efficiency. In a recent study, the authors report that the nanotopography of calcite surfaces leads to heterogonous sorption of europium due to differences in the atomic configuration of the adsorption sites [1].
In this study, we investigate the influence of muscovite surface site coordination on the adsorption energy barrier and the resulting overall distribution of radionuclide adsorption on the mineral surface. Numerical methods are applied to study the adsorption of Eu(OH)3 on a muscovite (001) surface with different nanotopographic structures. Density Functional Theory (DFT) calculations are performed for eleven surface sites present on muscovite to obtain the adsorption energy barriers. The adsorption energy barrier is calculated based on a series of geometry optimizations with increasing Eu–site distance. All site-specific adsorption energy barriers are then implemented in a Kinetic Monte Carlo (KMC) model developed based on a previous study [2]. Here, larger muscovite surface portions can be simulated with structures such as dissolution etch pits for a more realistic nanotopography. Eu(OH)3 is then adsorbed on the generated muscovite surface considering the adsorption energy barriers obtained from DFT calculations. The distribution of adsorbed Eu(OH)3 and the temporal evolution of the process can be simulated with KMC and linked to the surface structures. This combined numerical approach allows us to show the effects of surface site coordination on radionuclide adsorption reactions and the resulting adsorption heterogeneity on mineral surfaces at larger scales.
References:
[1] T. Yuan, S. Schymura, T. Bollermann, K. Molodtsov, P. Chekhonin, M. Schmidt, T. Stumpf, C. Fischer, Environ. Sci. Technol. 2021, 55, 15797–15809. [2] J. Schabernack, I. Kurganskaya, C. Fischer, A. Luttge, Minerals 2021, 11, 468.

  • Lecture (Conference)
    Jahrestagung der Fachgruppe Nuklearchemie 2022, 04.-06.10.2022, Bergisch Gladbach, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-34645
Publ.-Id: 34645


Unusual dynamics of the ferroelectric phase transition in K1−xLixTaO3 crystals

Nuzhnyy, D.; Bovtun, V.; Buixaderas, E.; Petzelt, J.; Savinov, M.; Kempa, M.; Paściak, M.; Rafalovskyi, I.; Chelod Paingad, V.; Kužel, P.; Kamba, S.; Repček, D.; Pashkin, O.; Trepakov, V. A.; Trybuła, Z.

K1−xLixTaO3 (x=0.043, 0.08) crystals, characterized by pyroelectric current with calculated spontaneous polarization and zero-field second-harmonic generation, have been studied by broadband dielectric spectroscopy, including time-domain terahertz transmission and infrared (IR) reflectivity, and by polarized Raman spectroscopy in the 10–300 K temperature range. This multiexperimental approach has proven the percolative nature of the ferroelectric (FE) transition at low temperatures and demonstrated that the FE phase is inherently inhomogeneous and displays coexistence of FE and relaxor regions. Thanks to the very broad frequency range studied (from 1 Hz to 20 THz), the relevant excitations were identified and fitted in the dielectric response of both crystals: three relaxations, a central mode (CM), and a soft mode (SM) that splits into three components on cooling. Two Cole-Cole relaxations (assigned to flipping of polar nanoregions around the Li+ ions by π/2 and π, in agreement with the known literature), thermally activated below ∼150K, but staying in the gigahertz range at higher temperatures, do not show any frequency anomaly at the FE transition and are therefore related to the non-FE parts of the sample volume. A third thermally activated relaxation of unusually slow dynamics was revealed at low frequencies and preliminary assigned to an expected critical relaxation connected with the percolative nature of the FE phase transition. The IR SM, which undergoes much less softening than in the undoped KTaO3, splits into three components below the FE transition. Two higher-frequency components correspond to the FE volume part of the crystals assigned to the split A1 and E modes due to the cubic-tetragonal transition. The third low-frequency component is assigned to the non-FE (relaxor) volume part. Our assignment was confirmed by modeling the terahertz-IR response of the SM using the Bruggeman model within the effective medium approach. Below the SM response, an additional CM in the 1011Hz range in the whole temperature range is inferred from the fits.

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Permalink: https://www.hzdr.de/publications/Publ-34644
Publ.-Id: 34644


Validation of a heat-pipe experiment using CFD

Höhne, T.

Heat pipes are playing a more important role in many industrial applications, particularly in improving the thermal performance of heat exchangers and increasing energy savings in applications with commercial use. In this paper, a Computational Fluid Dynamics (CFD) model was built to simulate the details of the steam/water two-phase flow and heat transfer phenomena during the operation of a heat pipe. The homogeneous model in ANSYS CFX was used for the simulation. The evaporation, condensation and phase change processes were modelled. The 3D simulations could reproduce the heat and mass transfer processes in comparison with experiments from the literature. Reasonable good agreement was observed between CFD temperature profiles in relation with experimental data.

Keywords: Two-phase flow; Boiling; CFD; Condensation; Heat-pipe

  • Contribution to proceedings
    CONV-22: International Symposium on Convective Heat and Mass Transfer, 05.-10.06.2022, Izmir, Türkei

Permalink: https://www.hzdr.de/publications/Publ-34643
Publ.-Id: 34643


Intensity scaling limitations of laser-driven proton acceleration in the TNSA-regime

Keppler, S.; Elkina, N.; Becker, G. A.; Hein, J.; Hornung, M.; Mäusezahl, M.; Rödel, C.; Tamer, I.; Zepf, M.; Kaluza, M. C.

We report on experimental results on laser-driven proton acceleration using high-intensity laser pulses. We present power law scalings of the maximum proton energy with laser pulse energy and show that the scaling exponent ξ strongly depends on the scale length of the preplasma, which is affected by the temporal intensity contrast. At lower laser intensities, a shortening of the scale length leads to a transition from a square root toward a linear scaling. Above a certain threshold, however, a significant deviation from this scaling is observed. Two-dimensional particle-in-cell simulations show that, in this case, the electric field accelerating the ions is generated earlier and has a higher amplitude. However, since the acceleration process starts earlier as well, the fastest protons outrun the region of highest field strength, ultimately rendering the acceleration less effective. Our investigations thus point to a principle limitation of the proton energy in the target normal sheath acceleration regime, which would explain why a significant increase of the maximum proton energy above the limit of 100 MeV has not yet been achieved.

Keywords: laser; plasma; TNSA; particle-in-cell simulation; preplasma

Permalink: https://www.hzdr.de/publications/Publ-34642
Publ.-Id: 34642


V0036: Chemical Flowers: buoyancy-driven instabilities under modulated gravity

Stergiou, Y.; Horvath, D.; Schuszter, G.; Hauser, M.; de Wit, A.; Eckert, K.; Schwarzenberger, K.

In this video, we present experiments of a miscible reactive horizontal displacement in a radial Hele-Shaw cell under modulating gravity levels.Initially, the Hele-Shaw cells are filled with a colorless solution of KSCN, and the injected fluid is a colorless solution of FeNO3. When the two solutions react, a complex ion (FeSCN2+) forms resulting in a red-colored product solution. Due to the direct visualization of the formed product using a white LED light array and a monochrome camera, this chemical system is convenient to study reaction-diffusion-convection fronts [1]. The gravity modulations were achieved aboard the 73rd ESA Parabolic Flight Campaign that took place in October, 2020 in Paderborn, Germany. The parabolic flight allowed for experiments under micro-g, normal-g and hyper-g conditions and the transition between them. These experiments provided detailed insights in a previously investigated [2] buoyancy-driven instability. In particular, the effect of hyper-g and multiaxial acceleration on the pattern formation was revealed. The observation of the system under micro-g confirmed that no instability develops in the absence of buoyancy effects.

[1] A. Tóth, G. Schuszter, N.P. Das, E. Lantos, D. Horváth, A. De Wit, F. Brau, Effects of radial injection and solution thickness on the dynamics of confined A+ B→ C chemical fronts. Phys Chem Chem Phys, 22(18), 2020

[2] F. Haudin, L. A. Riolfo, B. Knaepen, G. M. Homsy, A. De Wit. Experimental study of a buoyancy-driven instability of a miscible horizontal displacement in a Hele-Shaw cell. Phys. Fluids, 26(4), 2014

Permalink: https://www.hzdr.de/publications/Publ-34641
Publ.-Id: 34641


Tuning of the Dzyaloshinskii-Moriya interaction by He+ ion irradiation

Nembach, H. T.; Jué, E.; Potzger, K.; Faßbender, J.; Silva, T. J.; Shaw, J. M.

We studied the impact of He+ irradiation on the Dzyaloshinskii-Moriya interaction (DMI) in Ta/Co20Fe60B20/Pt/MgO samples. We found that irradiation of 40 keV He+ ions increases the DMI by approximately 20% for fluences up to 2 × 1016 ions/cm2 before it decreases for higher fluence values. In contrast, the interfacial anisotropy shows a distinctly different fluence dependence. To better understand the impact of the ion irradiation on the Ta and Pt interfaces with the Co20Fe60B20 layer, we carried out Monte-Carlo simulations, which showed an expected increase in disorder at the interfaces. A moderate increase in disorder increases the total number of triplets for the three-site exchange mechanism and consequently increases the DMI. Our results demonstrate the significance of disorder for the total DMI.

Keywords: Dzyaloshinskii-Moriya interaction; Fluence dependence; Ions irradiation

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Chemical Behavior of Long-Lived Fission and Activation Products in the Near Field of a Nuclear Waste Repository and the Possibilities of their Retention (Vespa II)

Mayordomo, N.; Altmaier, M.; Bischofer, B.; Bosbach, D.; Gaona, X.; Hagemann, S.; Müller, K.

To ensure a reliable and long-term safety assessment of high-level radioactive waste disposal, it is essential to study the physico-chemical properties of the radionuclides within spent nuclear fuel as well as their transport behavior expected under conditions of the near- and far-field of a nuclear waste repository. Among the radionuclide inventory, long-lived mobile fission products are of high concern since they can strongly contribute to the total biosphere dose from spent nuclear fuel disposal. The collaborative project VESPA “Chemical Behavior of Long-Lived Fission and Activation Products in the Near Field of a Nuclear Waste Repository and the Possibilities of their Retention - Phase II” aims to investigate the solubility and the immobilization of Tc-99, I-129, Cs-137, and Se-79. In particular, the focus is set on (1) the source term, evaluating, e.g., the I-129 inventory together with the instant release fraction and its speciation; (2) the effect of geochemical conditions in the near-field, i.e. T, p, Eh, pH, on the processes of surface redox-mediation and secondary mineral phase formation; (3) the solution chemistry, determining solubility products, complex formation and activity coefficients of Tc(IV) in presence of anions and small organic molecules, and Se(IV), Se(0), Cs(I) and I(-I) at elevated temperature; and (4) the retention behavior of I, Se and Tc on layered double hydroxides (LDH) and Fe-corrosion products. Finally, safety analysis calculations link the obtained results and provide an enhanced confidence in predictive risk assessments.

The authors acknowledge the German Federal Ministry of Economic Affairs and Climate Action (BMWK) for the funding (02 E 11607A-D). Further information is given at https://vespa2.grs.de/.

Keywords: Fission products; Near Field; Nuclear waste repository

  • Poster
    19th Radiochemical conference, 15.-20.05.2022, Marienbad, Czech Republic

Permalink: https://www.hzdr.de/publications/Publ-34639
Publ.-Id: 34639


Tc(VII) reductive immobilization by Sn(II) pre-sorbed on alumina nanoparticles.

Mayordomo, N.; Rodríguez, D. M.; Roßberg, A.; Scheinost, A.; Müller, K.

The interaction of highly mobile radioactive elements in the spent fuel with the different technical and geological barriers of a nuclear waste repository needs quantification and mechanistic understanding to allow a reliable safety assessment.
One of the most concerning mobile fission products is Tc-99. It is a long-lived radionuclide (half-life of 0.213 million years) that is expected to occur as Tc(VII) under oxidizing conditions and as Tc(IV) under reducing conditions. The anion pertechnetate (TcO₄⁻) is the main species of Tc(VII) and it is known to be a highly mobile species since it barely interacts with mineral surfaces. On the contrary, TcO₂ is the main species of Tc(IV) and it is a hardly soluble solid. Therefore, the reduction of Tc(VII) to Tc(IV) limits the mobility of Tc in water and is triggered by reducing agents such as Fe(II) or Sn(II). [1] In a previous work, we have observed that pre-sorption of Fe(II) on alumina enabled the Tc(VII) reduction at the interface, even at low pH values when Tc(VII) reduction by Fe(II) was expected to be limited due to the low sorption of Fe(II) on alumina. [2] In this study we focus on the impact of Sn(II).
We have performed sorption experiments following a stepwise strategy to ensure that Tc(VII) reduction by Sn(II) occurred at the interface (heteroreduction). i) Sn(II) was sorbed on alumina, ii) the Sn(II) pre-sorbed on alumina solid was isolated and dried, iii) a solution of Tc(VII) was added to this modified alumina, and iv) the yield of Tc removal by Sn(II) pre-sorbed on alumina was analyzed. The resulting Tc-containing solid was analyzed by X-ray absorption spectroscopy (XAS) at the Rossendorf Beamline (ROBL) at the European Synchrotron Radiation Facility in Grenoble (France).
Re-oxidation experiments were performed in samples where Tc(VII) reduction by Sn(II) was obtained by different pathways: i) Tc(VII) direct reduction by dissolved Sn(II) (homoreduction) and ii) Tc(VII) reduction by Sn(II) pre-sorbed on alumina (heteroreduction).
The results show that Tc(VII) is reduced to Tc(IV) with a high yield (85-100% removal from solution), being maximum at pH values between 3.5 and 9.5, and minimum at pH 10. Re-oxidation studies show that Tc(IV) obtained by heteroreduction presents lower oxidation kinetics than Tc(IV) obtained by homoreduction. These results support that the presence of alumina plays an important role by preventing Tc(IV) re-oxidation.
Acknowledgements
The authors acknowledge the German Federal Ministry of Economic Affairs and Climate Action (BMWK) for the Vespa II project funding (02 E 11607B).
References
[1] Owunwanne, A., Church, L. B. & Blau, M. Effect of oxygen on the reduction of pertechnetate by Stannous ion. J. Nucl. Med. 18, 822–826 (1977).
[2] Mayordomo, N. et al. Technetium retention by gamma alumina nanoparticles and the effect of sorbed Fe2+. J. Hazard. Mater. 388, 122066 (2020).

Keywords: Techenetium; Reduction; X-ray absorption spectroscopy

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  • Lecture (Conference)
    19th Radiochemical conference, 15.-20.05.2022, Marienbad, Czech Republic

Permalink: https://www.hzdr.de/publications/Publ-34638
Publ.-Id: 34638


Dosimetric Measurements using Radioluminescence of Beryllium Oxide

Kahle, P.; Döhler, D. D.; Gantz, S.; Gebauer, B.; van Goethem, M. J.; van der Graaf, E. R.; Metzner, E.; Pawelke, J.; Teichmann, T.; Werner, T.; Wratil, R.; Kormoll, T.

Abstract— The application of ionizing radiation in cancer therapy requires dosimetric verification and quality assurance of the applied therapeutic dose. Conventionally, ionization chambers are used for this purpose. At Technische Universität Dresden an alternative approach to the ionization chamber is under investigation. The detector system is based on a beryllium oxide (BeO) probe coupled to an optical fiber. Radioluminescence in the material generates photons proportional to the dose absorbed in the probe. The photons are counted by very sensitive time resolving single photon counting heads. Connected to the cylindrical BeO probe with a diameter of about 1 mm is a long, thin and flexible fiber, which allows measurements in complex and narrow geometries. Because of the system properties, real-time dosimetry in fields of high dose rates and steep gradients with a high spatial resolution is possible. The first experiments with the detection system were performed in photon and electron fields. In photon fields, the problem of Cherenkov radiation arises, which has already been successfully eliminated by temporal discrimination of the detected events. The current research concentrates on the use in fields of heavy charged particles. In this application, saturation effects appear in the high linear energy transfer (LET) area, like in other luminophores. In consequence, a correction function is required. Such a correction function has been determined for proton fields as a function of the LET-connected dependencies in the spectral composition of the radioluminescence light and has been already successfully tested.

I. INTRODUCTION
The presented measuring system consists of a BeO probe connected to a long and thin fiber. In the BeO probe, photons are emitted when exposing the probe to ionizing radiation. This effect is called radioluminescence. The generated signal is proportional to the dose absorbed in the probe. This principle offers several advantages for clinical use, like a high spatial resolution as well as resistance against external influences, such as magnetic fields and temperature changes. Unfortunately, drawbacks appear which have to be addressed according to the incident radiation type.

II. MEASURING PRINCIPLES
A. Beryllium Oxide Probe and Light Guide
The cylindrical BeO probe has a diameter and a height of 1 mm each and is coupled to the light guiding fiber with transparent epoxy (figure 1). To reduce ionization in the fiber, its diameter is only 0.2 mm. The length of the fiber is 5 m to achieve flexibility in the measuring setup [1]. Furthermore, the probe and the light guide are encased by a black coating to shield the fiber from external light. When ionizing radiation hits the BeO probe, photons are emitted whose number is proportional to the dose. They are guided by the light guide to the detection unit of the system.

B. Integration of a Beam Splitter
In case of photon or electron radiation, the radioluminesence spectrum in BeO has one broad maximum [2].
In contrast, if protons are the incident particles, the spectrum has two maxima and a minimum between them. To separate these maxima, a beam splitter was integrated in the measuring setup whose edge lays in the minimum of the spectrum. The beam splitter divides the photons with wavelengths over 347 nm and the ones with wavelengths under 347 nm. This gives the possibility to differentiate the two groups of photons in the analysis. Therefore, the corresponding events are collected in two separated channels [3]. Both exits of the beam splitter are connected to an own single
photon counting head (SPCH) based on the μPMT technology. These SPCHs by Hamamatsu are very sensitive, so that every photon can be counted. The sensitive area of the SPCHs amounts only 3 mm2 to reduce direct ionization [1]. With this measurement setup the ratio of the number of photons with low wavelengths and the ones with high wavelengths can be determined. This ratio is called γ in the following.

III. MEASUREMENTS
A. Depth Dose Curves in a Water Phantom As shown in [2], in a photon field the depth dose curve measured in a water phantom follows the course of the reference data, when using the method of gated discrimination to eliminate the Cherenkov radiation. Gated discrimination uses the fact, that the decay time of the Cherenkov radiation is much smaller (~ps) than the luminescence lifetime of BeO, which amounts 27 μs. In consequence, the luminescence of BeO is only measured after the decay time of the Cherenkov radiation [2]. In the next step, the detector system was tested in a homogenous (5 x 5) cm2 proton field at the experimental room of University Proton Therapy Dresden (UPTD) using the pencil beam scanning (PBS) nozzle. To examine the dependence of the signal to the residual range of the incident particles, the BeO probe is moved linearly in the water
phantom (figure 2) to record a depth dose curve for a quasi-mono-energetic beam of 110.7 MeV. In proton fields, the measured curves are correlated to the characteristic proton depth dose curve, but with rising LET (deeper position) saturation effects appear (see figure 3). A possible solution for this problem is a correction function. This function can be derived from the ratio between the two detection channels, which is mentioned above as γ. It was observed that γ increases with the penetration depth and consequently increases with a rising LET.

IV. ANALYSIS IN PROTON BEAMS
The correction function to convert the measured light signal into a dose-to-water value (𝐷real) should have the form 𝐷real =𝑓(𝛾)∙𝑀BeO ,
where Dreal names the reference dose, measured with an Advanced Markus Chamber TM34045 (PTW, Freiburg, Germany), f(𝛾) describes the correction function and MBeO is used as symbol for the measuring effect of the BeO probe with wavelengths smaller than 347 nm. This channel was choosed, because the curve has a steeper gradient (see figure 3). Accordingly, the correction function can be determined by approximating the dependency of Dreal/MBeO on γ. Figure 3 shows the depth dose curve, measured with the Markus Chamber, the depth dose curves measured with the BeO probe and the corrected data measured with the BeO probe. Comparing the BeO data and the data of the Markus Chamber, the saturation effect in the BeO probe in high LET region is clearly recognizable.

V. DISCUSSION
The measured curve of the BeO probe follows the course of the characteristic depth dose curve of protons. For not underestimating the dose, the correction function is necessary. The corrected data fit pretty well with the data of the Markus Chamber, hence the position of the Bragg-Peak can be
determined very precisely. However, the maximum of the Bragg Peak was overestimated by the corrected data by 2.3%, because of fluctuations in the ratio Dreal/MBeO.

VI. CONCLUSION AND OUTLOOK
The data measured by the BeO probe were successfully corrected for photon irradiation by gated discrimination and for proton irradiation with a correction as a function of spectral information. In further experiments, the behavior of the BeO probe in fields of charged particles, which are heavier than protons, will be investigated. Furthermore, the small size of the BeO probe has the potential for spot-wise dosimetry or small-field-dosimetry.

ACKNOWLEDGMENT
The experimental part of the UPTD facility has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 730983 (INSPIRE).

Keywords: Beryllium Oxide; Fiber Dosimetry; Radioluminescence

  • Lecture (Conference)
    2022 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room Temperature Semiconductor Detector Conference, 05.-12.11.2022, Mailand, Italien

Permalink: https://www.hzdr.de/publications/Publ-34637
Publ.-Id: 34637


HELIPORT Logos

Knodel, O.

The guidance system HELIPORT aims to make the components or steps of the entire life cycle of a research project at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) discoverable, accessible, interoperable and reusable according to the FAIR principles. In particular, this data management solution deals with the entire lifecycle of research experiments, starting with the generation of the first digital objects, the workflows carried out and the actual publication of research results.

The initial logos of the HELIPORT platform are collected in this upload and are available as Open Access.

Keywords: HELIPORT; Logo

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Publ.-Id: 34636


P–Ru-Complexes with a Chelate-Bridge-Switch: A Comparison of 2-Picolyl and 2-Pyridyloxy Moieties as Bridging Ligands

Ehrlich, L.; Gericke, R.; Brendler, E.; Wagler, J.

Starting from [Ru(pyO)₂(nbd)] 1 and a N,P,N-tridentate ligand (2a: PhP(pic)₂, 2b: PhP(pyO)₂) (nbd = 2,5-norbornadiene, pic = 2-picolyl = 2-pyridylmethyl, pyO = 2-pyridyloxy = pyridine-2-olate), the compounds [PhP(μ-pic)₂(μ-pyO)Ru(κ²-pyO)] (3a) and [PhP(μ-pyO)₃Ru(κ²-pyO)] (3b), respectively, were prepared. Reaction of compounds 3 with CO and CNtBu afforded the opening of the Ru(κ²-pyO) chelate motif with the formation of compounds [PhP(μ-pic)₂(μ-pyO)Ru(κ-O-pyO)(CO)] (4a), [PhP(μ-pic)₂(μ-pyO)₂Ru(CNtBu)] (5a), [PhP(μ-pyO)₄Ru(CO)] (4b) and [PhP(μ-pyO)₄Ru(CNtBu)] (5b). In dichloromethane solution, 4a underwent a reaction with the solvent, i.e., substitution of the dangling pyO ligand by chloride with the formation of [PhP(μ-pic)₂(μ-pyO)Ru(Cl)(CO)] (6a). The new complexes 3a, 4a, 5a, 5b and 6a were characterized by single-crystal X-ray diffraction analyses and multi-nuclear (¹H, ¹³C, ³¹P) NMR spectroscopy. The different coordination behaviors of related pairs of molecules (i.e., pairs of 3, 4 and 5), which depend on the nature of the P–Ru-bridging ligand moieties (μ-pic vs. μ-pyO), were also studied via computational analyses using QTAIM (quantum theory of atoms in molecules) and NBO (natural bond orbital) approaches, as well as the NCI (non-covalent interactions descriptor) for weak intramolecular interactions.

Keywords: atoms-in-molecules; hemilabile; phosphane; ruthenium

Permalink: https://www.hzdr.de/publications/Publ-34635
Publ.-Id: 34635


NOVO - Neutron and Prompt Gamma-Ray Range Verification in Particle Therapy

Kögler, T.; Alagoz, E.; Ytre-Hauge, K. S.; Hysing, L. B.; Lathouwers, D.; Lionheart, W.; Obhodas, J.; Pausch, G.; Pettersen, H. E. S.; Ratliff, H. N.; Rovituso, M.; Schellhammer, S.; Setterdahl, L. M.; Skjerdal, K.; Sudac, D.; Turko, J. A. B.; Meric, I.

Due to its high sensitivity to anatomical changes, particle therapy will only unfold its full potential together with a functioning online range verification. We present a detector concept making use of a large fraction of the secondary particles available by hybrid prompt gamma-ray and fast neutron imaging. The system is expected to exhibit a high detection sensitivity to these particles, a high time, energy and position resolution, excellent pulse shape discrimination, and a small footprint. It comprises a quasi-monolithic organic detector array consisting of novel organic scintillators with dual-ended silicon photomultiplier light read-out and fast digitizers. The reconstruction of the proton range from the events registered by the detector is based on gamma/neutron scatter kinematics, cone back-projection and maximum likelihood expectation maximization. Multiple studies are currently ongoing investigating the feasibility of this concept on an experimental and simulation level. A first Monte Carlo simulation study involving realistic patient data and an idealized detector has revealed that a range-shift sensitivity of 1 mm per spot is attainable for clinical spot weights. These results demonstrate the potential of particle treatment verification by fast neutrons and prompt gamma-rays and strengthen the potential of this hybrid system for clinical application.

Keywords: particle therapy; range verification; fast neutrons; prompt gamma rays; imaging

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  • Lecture (Conference) (Online presentation)
    IEEE Medical Imaging Conference 2022, 05.-12.11.2022, Milano, Italy

Permalink: https://www.hzdr.de/publications/Publ-34632
Publ.-Id: 34632


Development of a proton bunch monitor for treatment verification in particle therapy

Kögler, T.; Franke, A.; Makarevich, K.; Römer, K.; Tiebel, J.; Turko, J. A. B.; Wagner, A.; Weinberger, D.; Werner, R.-D.; Schellhammer, S.

Treatment verification is a key element in future online-adaptive particle therapy. As a light-weight, collimator-free technique, Prompt γ-Ray Timing is a promising candidate for this purpose. The development of such a system for clinical application is challenging due to instabilities in the accelerator phase relation.
We present two proton bunch monitors which are capable of measuring and ultimately correct for these instabilities. Firstly, a diamond detector to be placed at the beam energy degrader was investigated. It was found to exhibit an excellent time resolution 82(6) ps and to be able to monitor the phase instability with sufficient precision in a realistic geometry. Secondly, a phase pick-up installed in the low level radio frequency module of the accelerator was used. The data acquired with this monitor showed a very good agreement with the diamond detector with smaller statistical fluctuations. In conclusion, both proton bunch monitors were shown to resolve phase instabilities in Prompt γ-Ray Timing and are expected to strengthen the potential of this system for clinical application.

Keywords: particle therapy; range verification; prompt gamma ray timing; proton bunch monitoring; diamond detector

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  • Lecture (Conference) (Online presentation)
    IEEE Medical Imaging Conference 2022, 05.-12.11.2022, Milano, Italy

Permalink: https://www.hzdr.de/publications/Publ-34631
Publ.-Id: 34631


Data publication: Calorimeter with Bayesian unfolding of spectra of high-flux broadband X-rays

Laso García, A.; Hannasch, A.; Molodtsova, M.; Ferrari, A.; Couperus Cabadağ, J. P.; Downer, M. C.; Irman, A.; Kraft, S.; Metzkes-Ng, J.; Naumann, L.; Prencipe, I.; Schramm, U.; Zeil, K.; Zgadzaj, R.; Ziegler, T.; Cowan, T.

Data for the publication: Calorimeter with Bayesian unfolding of spectra of high-flux broadband X-rays Containing: - Raw datasets - Source code for extracting calibrated energy information from datasets - Source code for simulations - Source code for unfolding of spectra

Keywords: Technique and instrumentation; Relativistic laser plasmas; X-rays; Bremsstrahlung

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Publ.-Id: 34630


A proposal for calibration with locally varying references

van den Boogaart, K. G.; Tolosana Delgado, R.; Renno, A.

Local Analysis aims at quantifying the local material composition at small measurement location, in larger heterogeneous specimen. In many cases it is technically impossible to produce homogeneous samples of that material classes to provide homogeneous standards or reference materials. The corresponding reasons are manifold, for example not reaching thermodynamic equilibrium, kinetic delays in crystallization, exsolution in solid solutions or immiscibility in glass-forming melts.

We therefore propose a class of methods to be coined “local calibration”, which would allow to establish traceability of local chemical measurements based on references consisting of heterogeneous reference specimen along with a new kind of description/certification for local analytical methods. Such a certification would not only define a single reference value, minimum sample size and accuracy, but describe in more detail, how the material can be used as reference, Such a description could for instance provide a measurement mask or rule ensuring that only certain minerals are used in reference measurements, or it could include a description of the local concentrations in a specimen with locally varying concentrations. The kinds of descriptions would depend on the type of heterogeneity of the reference specimen, the characteristics of the local measurement procedure it is certified for (like e.g. the interaction volume, or whether the method is destructive) and on technologies available for the description process. The methodology includes a validation procedure ensuring traceability.

The methodology is based on a simple observation: Local analysis only depends on a local material portion, and will deliver measurement values dependent of the local composition irrespective of a larger scale heterogeneity or homogeneity of the larger specimen. It is thus sufficient to provide an accurate and traceable value for the measurements which will be actually done during the use of the reference specimen. Depending on the type of heterogeneity this is however possible through various statistical and analytical strategies, such as, e.g. establishing a local map using a calibrated reference technique if such a technique is available, providing a geostatistical interpolation in case of slowly varying local concentration gradients, or by physical modeling the source of concentration differences (e.g. in case of a growth gradient). In each case all aspects of such a description can be checked statistically, based on control measurements.

Keywords: calibration; tracebility; heterogenious material

  • Lecture (Conference)
    Geoanalysis 2022, 06.-12.08.2022, Freiberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-34628
Publ.-Id: 34628


Local control after locally ablative, image-guided radiotherapy of oligometastases identified by Gallium-68-PSMA-Positron Emission Tomography in castration-sensitive prostate cancer patients (OLI-P)

Hölscher, T.; Baumann, M.; Kotzerke, J.; Zöphel, K.; Paulsen, F.; Müller, A.; Zips, D.; Thomas, C.; Wirth, M.; Troost, E. G. C.; Krause, M.; Löck, S.; Lohaus, F.

Progression of prostate-specific antigen (PSA) values after curative treatment of prostate
cancer patients is common. Prostate-specific membrane antigen (PSMA-) PET imaging can identify
patients with metachronous oligometastatic disease even at low PSA levels. Metastases-directed
local ablative radiotherapy (aRT) has been shown to be a safe treatment option. In this prospective
clinical trial, we evaluated local control and the pattern of tumor progression. Between 2014 and 2018,
63 patients received aRT of 89 metastases (MET) (68 lymph node (LN-)MET and 21 bony (OSS-)MET)
with one of two radiation treatment schedules: 50 Gy in 2 Gy fractions in 34 MET or 30 Gy in 10 Gy
fractions in 55 MET. The mean gross tumor volume and planning target volume were 2.2 and 14.9 mL,
respectively. The median follow-up time was 40.7 months. Local progression occurred in seven MET,
resulting in a local control rate of 93.5% after three years. Neither treatment schedule, target volume,
nor type of lesion was associated with local progression. Regional progression in the proximity to the
LN-MET was observed in 19 of 47 patients with at least one LN-MET (actuarial 59.3% free of regional
progression after 3 years). In 33 patients (52%), a distant progression was reported. The median time
to first tumor-related clinical event was 16.6 months, and 22.2% of patients had no tumor-related
clinical event after three years. A total of 14 patients (22%) had another aRT. In conclusion, local
ablative radiotherapy in patients with PSMA-PET staged oligometastatic prostate cancer may achieve
local control, but regional or distant progression is common. Further studies are warranted, e.g., to
define the optimal target volume coverage in LN-MET and OSS-MET.

Keywords: prostatic neoplasms; prospective studies; radiotherapy; image-guided; radiosurgery; positron emission tomography; prostate-specific antigen; neoplasm metastasis; local control

Permalink: https://www.hzdr.de/publications/Publ-34626
Publ.-Id: 34626


Hybrid in-vivo treatment verification for particle therapy: Multivariate modelling of fast neutron and gamma-ray detection

Pettersen, H. E. S.; Schellhammer, S.; Löck, S.; Kögler, T.; Meric, I.

Given its sensitivity to anatomical variations, par-
ticle therapy is expected to benefit strongly from reliable on-
line treatment verification. Making use of a large fraction of
the secondary particles available, hybrid prompt gamma-ray and
fast neutron imaging is a promising approach for this purpose.
We present a simulation study introducing a novel method
for range reconstruction by means of these particles. To this
end, the passage of a proton beam through a patient and the
detection of secondary particles in a dedicated detector array
were simulated by Monte Carlo particle transport calculations.
Anatomical variations were mimicked by adding or removing
tissue to the patient. The secondary particle production vertices
were reconstructed from the events registered by the detector
based on scatter kinematics and maximum likelihood expectation
maximisation. The vertices were projected onto the beam axis
and the most predictive features of the resulting distributions
were identified from a standardised feature set by forward
feature selection and the Least Absolute Shrinkage and Selection
Operator (LASSO). A range-shift sensitivity of 1 mm or less
was reached at intensities of 1.2×10 7 protons per spot with
fast neutrons, and at 2.6×10 7 protons per spot with prompt
gamma-rays. These results demonstrate the potential of particle
treatment verification by fast neutrons and prompt gamma-rays
and strengthen the potential of this hybrid system for clinical
application.

Keywords: Treatment verification; fast neutron; prompt gamma-rays; feature selection; particle therapy

  • Lecture (Conference)
    2022 IEEE Nuclear Science Symposium (NSS), Medical Imaging Conference (MIC) and Room Temperature Semiconductor Detector (RTSD) Conference, 05.-12.11.2022, Milano, Italia

Permalink: https://www.hzdr.de/publications/Publ-34625
Publ.-Id: 34625


Test of the detector system for the Stopping Target Monitor of the Mu2e experiment in the presence of a high flux gamma background

Price, J.; Müller, S.; Ferrari, A.; Knodel, O.; Voigt, M.; Keshavarzi, A.; Motuk, E.; Judson, D.; Koltick, D.; Miller, J.; Plesniak, P.; Edmonds, A.; Ufer, R.; Huang, S.; Chen, J.; Chislett, R.; Lancaster, M.; Rachamin, R.; Tickle, S.; Alvarez, C.; Ginther, G.; Harkness-Brennan, L.

These data were taken to characterize the performance and test the data acquisition system of two detectors to be used to monitor the stopping target for the forth-coming Mu2e experiment at Fermilab; the High Purity Germanium (HPGe) and Lanthanum Bromide (LaBr) Detectors, in the presence of the pulsed gamma beam at ELBE. This measurement is crucial for the normalisation of the Mu2e experiment. The corresponding beamtime was carried out at the gELBE bremsstrahlung beamline of HZDR's ELBE radiation facility from April 21 to April 25, 2022 (GATE ID: 21202619-ST). The data sets represent the data taken with the LaBr detector by means of an ORTEC DSPEC 50 and a Lecroy/Teledyne HDO4104 oscilloscope.

Keywords: dataset; detector; HPGe; LaBr3; Stopping target Monitor (STM); Mu2e; gELBE; Data Mangement; DAQ; muon conversion

Related publications

  • DOI: 10.58065/24020 is cited by this (Id 34624) publication
  • DOI: 10.17815/jlsrf-2-58 is cited by this (Id 34624) publication
  • HANDLE: 20.500.12865/HZDR.Projects.2022.FWCC.Project.74 documents this (Id 34624) publication

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Permalink: https://www.hzdr.de/publications/Publ-34624
Publ.-Id: 34624


Horizont 2020 Projekt: „Sodium-Zinc molten salt batteries for low-cost stationary storage“

Weber, N.

Der Vortrag gibt einen Überblick über die Erfahrungen bei der Antragstellung des Horizon 2020-Projekts SOLSTICE.

  • Invited lecture (Conferences) (Online presentation)
    Aktuelle Förderinstrumente der EU im Bereich Energie - Details, Hinweise und Erfahrungsberichte, 11.05.2022, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-34622
Publ.-Id: 34622


Natrium-Zink Salzschmelzenbatterien als stationäre Energiespeicher

Weber, N.

Der Vortrag gibt einen Überblick über das Forschungsvorhaben SOLSTICE sowie die ersten Ergebnisse.

  • Invited lecture (Conferences)
    5. Vernetzungsveranstaltung im Bereich Energieinnovation - Chancen für sächsische und ostdeutsche Akteure, 13.05.2022, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-34621
Publ.-Id: 34621


Prospects for precise predictions of $a_\mu$ in the Standard Model

Colangelo, G.; Davier, M.; El-Khadra, A. X.; Hoferichter, M.; Lehner, C.; Lellouch, L.; Mibe, T.; Roberts, B. L.; Teubner, T.; Wittig, H.; Ananthanarayan, B.; Bashir, A.; Bijnens, J.; Blum, T.; Boyle, P.; Bray-Ali, N.; Caprini, I.; Carloni Calame, C. M.; Catà, O.; Cè, M.; Charles, J.; Christ, N. H.; Curciarello, F.; Danilkin, I.; Das, D.; Deineka, O.; Della Morte, M.; Denig, A.; Detar, C. E.; Dominguez, C. A.; Eichmann, G.; Fischer, C. S.; Gérardin, A.; Giusti, D.; Golterman, M.; Gottlieb, S.; Gülpers, V.; Hagelstein, F.; Hayakawa, M.; Hermansson-Truedsson, N.; Hoid, B.-L.; Holz, S.; Izubuchi, T.; Jüttner, A.; Keshavarzi, A.; Knecht, M.; Kronfeld, A. S.; Kubis, B.; Kupść, A.; Lahert, S.; Liu, K. F.; Lüdtke, J.; Lynch, M.; Malaescu, B.; Maltman, K.; Marciano, W.; Marinković, M. K.; Masjuan, P.; Meyer, H. B.; Müller, S.; Neil, E. T.; Passera, M.; Pepe, M.; Peris, S.; Petrov, A. A.; Procura, M.; Raya, K.; Rebhan, A.; Risch, A.; Rodríguez-Sánchez, A.; Roig, P.; Sánchez-Puertas, P.; Simula, S.; Stoffer, P.; Stokes, F. M.; Sugar, R.; Tsang, J. T.; van de Water, R. S.; Vaquero Avilés-Casco, A.; Venanzoni, G.; von Hippel, G. M.; Zhang, Z.

We discuss the prospects for improving the precision on the hadronic corrections to
the anomalous magnetic moment of the muon, and the plans of the Muon g − 2 Theory
Initiative to update the Standard Model prediction.

Keywords: muon anomalous magnetic moment; g-2; a_mu

Permalink: https://www.hzdr.de/publications/Publ-34620
Publ.-Id: 34620


Krebsforschung mit laserbeschleunigten Protonen

Kroll, F.; Zeil, K.; Brack, F.-E.; Beyreuther, E.

Durch Hochleistungslaser getriebene Protonenquellen stellen eine interessante Ergänzung zu konventionellen Protonenbeschleunigern dar, insbesondere für die radiobiologische Forschung. Unserem interdisziplinären Forschungsteam ist es erstmals gelungen, eine radiobiologische Kleintierstudie mit laserbeschleunigten Protonen durchzuführen.

Keywords: Laserbeschleunigung; Radiobiologie; Protonentherapie

Permalink: https://www.hzdr.de/publications/Publ-34619
Publ.-Id: 34619


The Training Catalogue for Photon and Neutron Data Services

Knodel, O.; Konrad, U.; Valcarcel-Orti, A.; Padovani, A.

Education is becoming an increasingly important topic to help scientists work on photon and neutron sources. Other relevant areas such as advanced quantum technologies will also play a key role in the future.

One of the goals of ExPaNDS (European Open Science Cloud (EOSC) Photon and Neutron Data Service) is to train research scientists in order to better understand the issues, methods and available computational RI infrastructures to address critical research questions.

Our PaN-training catalogue provides a one-stop shop for trainers and trainees to discover online information and content:

* For trainers the catalogue offers an environment for sharing materials and event information.
* For trainees, it offers a convenient gateway via which to identify relevant training events and resources, and to perform specific, guided analysis tasks via training workflows to provide FAIR research.

Keywords: training; photon science; neutron science; e-learning; catalogue; data management

Related publications

  • Open Access Logo Poster
    LEAPS meets Quantum Technology Conference, 15.-21.05.2022, La Biodola Bay, Elba Island, Italy
    DOI: 10.5281/zenodo.6491949
  • Open Access Logo Poster
    Annual EGI conference 2022, 20.-22.09.2022, Prague, Czech Republic
    DOI: 10.5281/zenodo.6491948
  • Open Access Logo Lecture (Conference)
    EOSC Symposium 2022, 14.-17.11.2022, Prag, Tschechische Republik
  • Open Access Logo Invited lecture (Conferences)
    ExPaNDS closing event, 23.-24.01.2023, Hamburg, Germany

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Permalink: https://www.hzdr.de/publications/Publ-34618
Publ.-Id: 34618


Process characterization in industrial vessels by flow-following sensor particles

Reinecke, S.; Buntkiel, L.; Kipping, R.; Hampel, U.

Instrumented flow-following sensor particles have been developed for investigation of hydrodynamic and biochemical processes in chemical reactors and bioreactors, where standard measurement techniques are not applicable. The sensor particles allow autonomous long-term measurement of spatially distributed process parameters in the chemically and mechanically harsh environments of e.g. agitated industrial vessels. Each sensor particle comprises of an on-board measurement electronics that logs the signals of the embedded sensors. A buoyancy control unit enables automated taring to achieve neutral buoyancy of the sensor particles. Moreover, controlled floating of the sensor particles is possible to expose them for recovery from the liquid surface. Macro-flow tracking of the sensor particles is validated with circulation time reference measurements by means of salt tracer experiments in a stirred model reactor and CFD simulations. Moreover, process characterization with sensor particles is demonstrated in three further applications, namely a biogas pilot digester, an air-water column and a biological wastewater treatment basin. Acquired data were used to fit mixing model parameters, namely effective circulation time, circulation number, degree of suspension and Péclet number.

Keywords: sensor particle; flow follower; flow tracking; mixing model; bioreactor

Permalink: https://www.hzdr.de/publications/Publ-34617
Publ.-Id: 34617


Magnetometric exploration of the phase diagrams of Yb-based delafossites

Luther, S.

The Yb-based delafossites NaYbCh2 (Ch = O, S, Se) are planar triangular-lattice spin systems with a trigonal crystal structure (space group R-3m). In these compounds, a strong spin-orbit coupling, combined with crystalline-electric-field effects, leads to a pronounced magnetic anisotropy and a pseudospin-1/2 spin-liquid ground state at low temperatures. The chalcogen series provides the possibility for tuning the interlayer distance and the associated exchange couplings by changing the chemical composition. The absence of magnetic long-range order at zero field down to lowest temperatures is strongly suggestive of a quantum spin-liquid ground state. Relaxation measurements by means of µSR and NMR have shown persistent strong fluctuations down to 100 mK at low magnetic fields. Based on specific-heat and magnetization experiments, we have observed magnetic order for out-of-plane fields exceeding 2 T for all three compounds. For in-plane fields of several tesla, a plateau-like feature in the magnetization indicates an up-up-down spin arrangement [1-3]. Furthermore, our measurements up to fields of 30 T allow to probe the saturation fields and polarized moments and, thus, the determination of the anisotropic exchange couplings [4]. Our 23Na NMR measurements of NaYbSe2 aim to probe the microscopic details of the field-induced magnetic structure in this compound. Measurements of the field-dependent transition temperature to long-range order via the 1/𝑇1-relaxation rate are in agreement with the specific-heat results. The in-plane up-up-down spin arrangement is leading to an asymmetric broadening of the NMR spectra. At elevated out-of-plane fields, an umbrella-type configuration of the magnetic moments is predicted and in agreement with a symmetric broadening of the 23Na NMR spectra. Low-field measurements reveal a monotonic low-temperature increase of the 1/𝑇1-relaxation rate and spectral broadening, without any signature of long-range order down to 0.3 K.

[1] M. Baenitz et al., Phys. Rev. B 98, 220409(R) (2018)
[2] K. M. Ranjith et al., Phys. Rev. B 99, 180401(R) (2019)
[3] K. M. Ranjith et al., Phys. Rev. B 100, 224417 (2019)
[4] B. Schmidt et al., Phys. Rev. B 103, 214445 (2021)

  • Lecture (others)
    IFPM Seminar, 17.05.2022, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-34616
Publ.-Id: 34616


A quasi-bivariate approach to tracking secondary particle properties within the class method framework

Lehnigk, R.; Lucas, D.; Niemi, T.; Peltola, J.; Schlegel, F.

In many polydisperse multiphase flows, the fluid or solid particles are not only distributed over size, but also with respect to other variables such as their velocity, shape, temperature or chemical composition, in which case the corresponding population balance is referred to as bi- or multivariate, respectively as two- or multidimensional. While industrial Computational Fluid Dynamics (CFD) simulations of disperse multiphase flows increasingly include approximate solutions of univariate population balance equations, e.g. for tracking the particle size distribution by means of class or quadrature-based moment methods, bivariate solution approaches are still a subject of research. This contribution highlights an aspect of recently published work (Lehnigk et al. 2022) [1], wherein a quasi-bivariate approach to tracking secondary particle properties in the class method framework is presented and demonstrated for the simulation of a bubbly flow in a vertical pipe as well as the synthesis of titania powder in a furnace reactor. In the former case, the velocity is selected as secondary property, since shear in the liquid phase can result in a pronounced radial separation of bubbles depending on their size. For the latter case, the surface area to volume ratio of the particle aggregates is used to describe the fractal-like shape of the aggregates, which influences the collision frequency and by extension also the aggregate size distribution.

[1] R. Lehnigk, W. Bainbridge, Y. Liao, D. Lucas, T. Niemi, J. Peltola, F. Schlegel, An open-source population balance modeling framework for the simulation of polydisperse multiphase flows, AIChe J. 68[3] (2022) e17539. https://doi.org/10.1002/aic.17539.

  • Poster
    7th International Conference on Population Balance Modelling (PBM 2022), 09.-11.05.2022, Lyon, Frankreich

Permalink: https://www.hzdr.de/publications/Publ-34615
Publ.-Id: 34615


Hybrid Classical-Quantum Machine Learning Algorithms for Large Scale Applications

Konar, D.

In this talk, I will be discussing primarily on quantum machine learning, quantum optimization, hybrid classical-quantum neural networks with a direct application on computer vision, material science etc. Hybrid classical-quantum spiking and Random neural networks are highly promising candidate for quantum advantage. We propose a novel framework to demonstrate the feasibility of Hybrid Classical-Quantum Neural Networks (HCQNN) employing Variational Quantum Circuit (VQC) in the dressed quantum layer. The HCQNN relies on a hybrid classical-quantum circuit with gate parameters optimized during training. The dressed quantum layer in the suggested DSQ-Net model as a VQC are capable of being trained with thousands of parameters employed in the architecture. The HCQNN model has been experimented on various computer vision datasets using the Penny Lane quantum simulator.
Moreover, we are also working on Hybrid Parameterized Quantum Supervised Learning Classifiers. To obviate the data reduction before feeding to the circuit, dense parameterized quantum circuits (VQC) with lesser number trainable parameters have been proposed without compromising the classification accuracy. Recently, we have developed Quantum Kernel Integrated Ridge Regression for the direct applications to material science which will be also the part of our discussion. Finally, I will shed some light in to the future of quantum machine learning and the feasibility of quantum deep learning for large-scale applications.

Keywords: Quantum computing; Quantum Machine Learning; Computer Vision; Quantum Neural Networks

  • Invited lecture (Conferences) (Online presentation)
    11th IEEE International Conference on Communication Systems and Network Technologies (CSNT 2022), 23.-24.04.2022, Indore, India

Permalink: https://www.hzdr.de/publications/Publ-34614
Publ.-Id: 34614


The Influence Of Surface Cover And Bedrock Geology On The Snow Geochemistry – An Example From Northern Finland

Taivalkoski, A.; Pospiech, S.; Middleton, M.; Lahaye, Y.; Kinnunen, J.

The idea of using snow in mineral exploration is due to the needs of environmentally friendly sampling methods for the ecologically sensitive northern areas. Not only the environmental issues, but the low costs of sampling and relieving permission issues encourage researchers to find new methods for mineral exploration. Surface geochemical methods, including sampling plants, topsoil horizons and snow can be considered in the areas where machinery is not allowed. Moreover, surface geochemical methods can provide the information of metal ions derived from the deep-seated mineralization below. The advantages of snow sampling are low volume of sample material, (comparably) light sample material and sampling equipment and therefore the option for low impact sampling campaign by skies or snowshoes.
In the New Exploration Technologies (NEXT) project*, 165 snow samples together with 13 field duplicate snow samples for quality control, were collected in March-April winter 2019. The aim was to estimate with statistical methods the usage of snow as a sampling material for mineral exploration. The samples were collected on the Rajapalot Au-Co prospect in northern Finland, 60 km west from Rovaniemi, operated by Mawson Oy. Stratified random sampling method was used to calculate sampling locations with balanced number of points per soil type and geophysical parameter, but randomly distributedwithin the strata over the test area. The samples were analysed in the Research Laboratory of the Geological Survey of Finland using a Nu AttoM single collector inductively coupled plasma mass spectrometry (SC-ICPMS) and returned analytical results for 52 elements at ppt level.
Of the analysed elements Ba, Ca, Li, Mg, Mo, Rb, Sr and V passed the strict quality control and were used for the final data analysis. Prior to statistical methods, the geochemical data was transformed to log-ratio scores in order to ensure that results are independent of the selection of elements and to avoid spurious correlations (compositional data approach). The results indicate strong dependency of the snow element composition to the soil type, meaning that there is systematic shift of element pattern if the snow sample was taken above mineral soil or organic soil. Thus, the soil type should be included in models to predict (geological) features below the surface or interpretation of snow data should be performed separately for different soil types. The impact of subsurface features on the snow geochemistry could only be tested indirectly by using geophysical data as proxy for characteristics of the basement rock. Based on linear models, it seems that snow geochemistry could be used as a mapping tool for delineating the areas of major geological units. Given the selection of analytical available elements, snow sampling could serve as a proxy where to continue exploration with different methods rather than directly pointing out the mineralized zones.

Keywords: snow; exploration; geochemistry; statistics; compositional data

  • Lecture (Conference)
    Nordic Geological Winter Meeting, Reykjavik, 11.-13.05.2022, Reykjavik, Iceland

Permalink: https://www.hzdr.de/publications/Publ-34613
Publ.-Id: 34613


A Scalable 5,6-Qubit Grover's Quantum Search Algorithm

Vemula, D. R.; Konar, D.; Satheesan, S.; Cangi, A.

Recent studies have been spurred on by the promise of advanced quantum computing technology, which has led to the development of quantum computer simulations on classical hardware. Grover's quantum search algorithm is one of the well-known applications of quantum computing, enabling quantum computers to perform a database search (unsorted array) and quadratically outperform their classical counterparts in terms of time. Given the restricted access to database search for an oracle model (black-box), researchers have demonstrated various implementations of Grover's circuit for two to four qubits on various platforms. However, larger search spaces have not yet been explored. In this paper, a scalable Quantum Grover Search algorithm is introduced and implemented using 5-qubit and 6-qubit quantum circuits, along with a design pattern for ease of building an Oracle for a higher order of qubits. For our implementation, the probability of finding the correct entity is in the high nineties. The accuracy of the proposed 5-qubit and 6-qubit circuits is benchmarked against the state-of-the-art implementations for 3-qubit and 4-qubit. Furthermore, the reusability of the proposed quantum circuits using subroutines is also illustrated by the opportunity for large-scale implementation of quantum algorithms in the future.

Keywords: Quantum Computing; Grover’s search algorithm; IBM quantum computer; qubit

Permalink: https://www.hzdr.de/publications/Publ-34612
Publ.-Id: 34612


Properties of Cr2AlC thin films disordered by ion-irradiation

Salgado Cabaco, J.; Kentsch, U.; Lindner, J.; Faßbender, J.; Leyens, C.; Bali, R.; Boucher, R.

MAX phases are nano-lamellar composite materials of the form Mn+1AXn, where n is 1, 2 or 3; M an early transition metal; A is an A-group element and X is carbon or nitrogen [1,2]. An interesting combination of metallic and ceramic properties as well as potential applications in spintronics [1,3] led to significant research interest in MAX phases. Literature on the effect of systematic disordering of the nano-laminar structure on the magnetic and transport properties is still limited. In particular, MAX phase systems doped with magnetic ions via ion-irradiation may result in large variations of the magneto-transport properties. Here we observe the magneto-transport properties and attempt to separate the contributions of structural changes due to the irradiation and magnetic effects due to the doping on the magneto-transport. A prototype material is Cr2AlC, formed from a unit cell of Cr2C sandwiched between atomic planes of Al. In this work, we study 50 nm and 500 nm thick thin films of Cr2AlC grown on Si (111) by sputtering and subsequent annealing. Structural characterization using X-ray Diffraction in Bragg-Brentano geometry shows a pronounced MAX phase, confirmed by the occurrence of the 002 superlattice reflection. The films were irradiated with Co+ at 450 (50) keV for the 500 (50) nm thick films. The Co+ fluence varied between 1×10^12 - 1×10^15 ions.cm^-2, in full order steps. The Co+ irradiation led to a gradual suppression of the 0002 superstructure reflection, while preserving the fundamental peaks, implying the intermixing of the nano-laminar MAX phase structure. The magnetic properties are characterized using vibrating sample magnetometry at low temperatures, showing an increasing paramagnetic behavior as the Co+-fluence increases. In comparison, magneto-resistance measurements show that for the 500 nm film thickness, the magnetoresistance reaches up to 3 % (10 T) for 100 K, at an optimized Co+-fluence of 5×10^13 ions.cm^-2. The above results suggest that in the low-fluence regime, the irradiation-induced disorder remains sufficiently low to obtain pronounced magneto-resistance values. Understanding the defect state in the optimized MAX phase films will shed light on the magneto-transport mechanisms in these nano-laminated materials.

Keywords: Ion Irradiation; X-ray diffraction; Disorder; MAX phases

Related publications

  • Poster
    22nd International Conference on Ion Beam Modification of Materials, 10.-15.07.2022, Lisbon, Portugal

Permalink: https://www.hzdr.de/publications/Publ-34611
Publ.-Id: 34611


Combining a SIMS with AMS: Super-SIMS at DREAMS - Status of this challenging initiative

Rugel, G.

At the DREAMS (DREsden AMS) facility [1,2] we are implementing a so-called Super-SIMS (SIMS =
Secondary Ion Mass Spectrometry) device [3] for specialized applications. The system combines the spatial
resolution capability of a commercial SIMS (CAMECA IMS 7f-auto) with AMS capability, which should
suppress molecular isobars in the ion beam allowing for the quantification of elemental abundances down to
~ E-9 - E-12. This would be more than an order of magnitude improvement over traditional dynamic SIMS
(e.g. [4,5]). We aim to use this for the highly sensitive analysis of geological samples in the context of
resource technology.
In the present setup, high efficiency transmission in the low-energy ion optics segment remains a challenge,
as the beam needs to traverse two existing magnet chambers without deflection, where no steering or lens
elements are available over a flight distance of 4 m. We have now improved the low-energy injection just
after the ion beam exits the 7f-auto, upgrading the steerers directly after the SIMS and by adding a beam
intensity attenuator. This provides both more stable conditions for instrument tuning and simplifies transition
between measurements of the beam intensity in Faraday cups and the gas ionization chamber. Regarding the
measurement of C, N and O in silicon, we found that a simple Wien-filter using permanent magnets for the
primary Cs-sputter beam significantly reduces the background at the detector, as the 7f-auto uses a Cs₂ CO₃
source – rather than metallic Cs – for the generation of the primary positive Cs beam.
Once the remaining issues associated with ion beam-path are fully addressed, we will still need to tackle the
issue of establishing suitable, well characterized reference materials needed for our first suite of resource and
geoscience applications (e.g., halides in naturally occurring sulphide minerals). We present ongoing
developments and results, as well as plans for extending to other matrices and isotope systems.
[1] S. Akhmadaliev et al., NIMB 294 (2013) 5. [2] G. Rugel et al. NIMB 370 (2016) 94. [3] J. M. Anthony,
D. J. Donahue, A. J. T. Jull, MRS Proceedings 69 (1986) 311-316. [4] C. Maden, PhD thesis, ETH Zurich
2003. [5] S. Matteson, Mass Spectrom. Rev., 27 (2008) 470.

Related publications

  • Invited lecture (Conferences) (Online presentation)
    National Workshop on "Chronological systematics and their applications in Earth Sciences", 19.-21.04.2022, New Delhi, India

Permalink: https://www.hzdr.de/publications/Publ-34610
Publ.-Id: 34610


Data Publication: Protein Enrichment by Foam Fractionation: Experiment and Modeling

Keshavarzi, B.; Krause, T.; Sikandar, S.; Schwarzenberger, K.; Eckert, K.; Ansorge-Schumacher, M.; Heitkam, S.

This work investigates the enrichment of bovine serum albumin (BSA) protein through foam fractionation. Here, we performed experiments using BSA and measured the recovery and grade of the extract. Additionally, an unsteady-state simulation of the protein foam fractionation process was carried out by numerically solving the liquid drainage equation in the foam. Thereby, the extracted liquid volume and protein concentration were calculated. Required quantities such as foam stability, interface coverage or bubble size distribution were measured in corresponding experiments and were fed into the model. The experiments showed that the foam coalescence accelerates the liquid drainage leading to dryer extract and higher protein enrichment. The modeling also reproduced the liquid recovery and extract concentration of the foam fractionation tests within a reasonable error range. The modeling solely relies on experimental inputs and does not require any tuning parameters. It can be further used for optimization or up-scaling of protein foam fractionation.

Keywords: Protein; foam fractionation; flotation; modeling; dynamic adsorption; surface equation of state; flow-on-bubble

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Permalink: https://www.hzdr.de/publications/Publ-34609
Publ.-Id: 34609


Protein Enrichment by Foam Fractionation: Experiment and Modeling

Keshavarzi, B.; Krause, T.; Sikandar, S.; Schwarzenberger, K.; Eckert, K.; Ansorge-Schumacher, M.; Heitkam, S.

This work investigates the enrichment of bovine serum albumin (BSA) protein through foam fractionation. Here, we performed experiments using BSA and measured the recovery and grade of the extract. Additionally, an unsteady-state simulation of the protein foam fractionation process was carried out by numerically solving the liquid drainage equation in the foam. Thereby, the extracted liquid volume and protein concentration were calculated. Required quantities such as foam stability, interface coverage or bubble size distribution were measured in corresponding experiments and were fed into the model. The experiments showed that the foam coalescence accelerates the liquid drainage leading to dryer extract and higher protein enrichment. The modeling also reproduced the liquid recovery and extract concentration of the foam fractionation tests within a reasonable error range. The modeling solely relies on experimental inputs and does not require any tuning parameters. It can be further used for optimization or up-scaling of protein foam fractionation.

Keywords: Protein; foam fractionation; flotation; modeling; dynamic adsorption; surface equation of state; flow-on-bubble

Related publications

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Permalink: https://www.hzdr.de/publications/Publ-34606
Publ.-Id: 34606


Generic Library for Asynchronous Data Operations and Streaming - GLADOS

Windisch, D.; Bieberle, A.

Generic Library for Asynchronous Data Operations and Streaming (GLADOS) provides a framework for data stream processing in a pipeline scheme. GLADOS provides a managed memory pool for device memory and host memory which allows high-throughput processing of streams without runtime memory allocations. GLADOS supports the fork-join paradigm to allow for parallel processing branches and the subject-observer pattern for asychnronous control of the process. Implementations of the processing steps use C++ templates and can therefore be adapted very flexibly.

Keywords: Pipeline; Data processing; C++; CUDA

Related publications

  • Software in external data repository
    Publication year 2022
    Programming language: C++, CUDA
    System requirements: Linux-based operating system, CUDA-capable GPU
    License: Apache-2.0 (Link to license text)
    Hosted on https://gitlab.hzdr.de/risa/GLADOS: Link to location

Permalink: https://www.hzdr.de/publications/Publ-34605
Publ.-Id: 34605


Real-time Image Stream Algorithms: Core Library - libRISA_Core

Windisch, D.; Bieberle, A.

Real-time image stream algorithms (RISA) is a high-throughput, low-latency image stream processing command-line application. Based on a configuration file, it will construct a processing pipeline of distinct processing steps and process a given image stream. Implementations of such processing steps are loaded from RISA-compatible shared libraries.

The libRISA_Core library includes basic image processing algorithms, e.g., for filtering, masking, transforming (FFT) and displaying data.

Keywords: Real-time; Image processing; Data processing; CUDA; C++

Related publications

  • Software in external data repository
    Publication year 2022
    Programming language: C++, CUDA
    System requirements: Linux-based operating system, CUDA-capable GPU
    License: Apache-2.0 (Link to license text)
    Hosted on https://gitlab.hzdr.de/risa/librisa_core: Link to location

Permalink: https://www.hzdr.de/publications/Publ-34604
Publ.-Id: 34604


Targeting CD10 on B-Cell Leukemia Using the Universal CAR T-Cell Platform (UniCAR)

Mitwasi, N.; Arndt, C.; Loureiro, L. R.; Kegler, A.; Fasslrinner, F.; Berndt, N.; Bergmann, R.; HoˇRejší, V.; Rössig, C.; Bachmann, M.; Feldmann, A.

Chimeric antigen receptor (CAR)-expressing T-cells are without a doubt a breakthrough therapy for hematological malignancies. Despite their success, clinical experience has revealed several challenges, which include relapse after targeting single antigens such as CD19 in the case of B-cell acute lymphoblastic leukemia (B-ALL), and the occurrence of side effects that could be severe in some cases. Therefore, it became clear that improved safety approaches, and targeting multiple antigens, should be considered to further improve CAR T-cell therapy for B-ALL. In this paper, we address both issues by investigating the use of CD10 as a therapeutic target for B-ALL with our switchable UniCAR system. The UniCAR platform is a modular platform that depends on the presence of two elements to function. These include UniCAR T-cells and the target modules (TMs), which cross-link the T-cells to their respective targets on tumor cells. The TMs function as keys that control the switchability of UniCAR T-cells. Here, we demonstrate that UniCAR T-cells, armed with anti-CD10 TM, can efficiently kill B-ALL cell lines, as well as patient-derived B-ALL blasts, thereby highlighting the exciting possibility for using CD10 as an emerging therapeutic target for B-cell malignancies.

Keywords: CD10; immunotherapy; CAR T-cells

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Permalink: https://www.hzdr.de/publications/Publ-34603
Publ.-Id: 34603


Teaching Workshop: Software Carpentry Workshop, Unix shell, Git, and Programming with Python

Zongru Doris Shao, R. H.

Teaching Software Carpentry Workshop

Keywords: Python; Git; Shell

  • Open Access Logo Lecture (others) (Online presentation)
    Software Carpentry Workshop, 16.-19.05.2022, University of Twente, online, Netherlands

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Permalink: https://www.hzdr.de/publications/Publ-34602
Publ.-Id: 34602


Personnel staffing and scheduling during COVID-19 pandemic: A contact network-based analysis

Batista German, A. C.; Senapati, A.; Davoodi Monfared, M.; Calabrese, J.

The COVID-19 pandemic has disrupted global operations, compromising people's health and safety. Several organizations, in particular, have been forced to shift their operations to a hybrid system (working from home) to prevent the spread of the virus and ensure employee safety. Although working from home is effective for some organizations, others need to find a balance between workplace occupancy and risk of infection to keep their operations functioning efficiently. We address this issue through contact network analysis by investigating the impact of employee interactions on virus spread in closed environments. We develop a staffing model for the scheduling of employees, considering contact networks. The goal is to maximize occupancy while minimizing the risk of infection. We aim to find the optimal composition of staff differing by priority to be allocated over a specified discrete-time horizon. We propose a Mixed Integer Non-Linear Programming (MINLP) model considering a Microscopic Markov Chain Approach (MMCA) to determine the probability of infection in a contact network based on the employee’s interactions. We assess the effectiveness of the approach through simulation, considering several contact network structures and interventions such as testing, vaccination, and personal protection. Through extensive computational analysis, we show that workplace occupancy can be efficiently balanced while keeping safety in the workplace.

Keywords: scheduling; optimization; disease modeling; Markov Chain

  • Open Access Logo Lecture (Conference)
    48th Annual Meeting of the Euro Working Group on Operational Research Applied to Health Services, 17.-22.07.2022, Bergamo, Italy

Permalink: https://www.hzdr.de/publications/Publ-34601
Publ.-Id: 34601


Therapeutic potential of repetitive AC-magnetic treatments on iPSC-derived motoneurons from ALS patients to improve axonal regeneration

Kandhavivorn, W.

lecture seminar for Ph.D. candidates at Center for Radiopharmaceutical Tumor Research (ZRT), HZDR
es hat keine Inhaltsangabe dafür vorgelegen

  • Lecture (others) (Online presentation)
    Lecture Seminar for Ph.D. candidates at Center for Radiopharmaceutical Tumor Research (ZRT), HZDR, 25.04.2022, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-34600
Publ.-Id: 34600


The application of AC-magnetic stimulations on iPSC-derived motoneurons from ALS patients to improve axonal regeneration for therapeutic potential in neurodegeneration

Kandhavivorn, W.

lecture in EGBE 693 Research Seminar for Biomedical Engineering II for graduate students at the Department of Biomedical Engineering, Faculty of Engineering, Mahidol University Thailand
es hat keine Inhaltsangabe dafür vorgelegen

  • Lecture (Conference) (Online presentation)
    EGBE 693 Research Seminar for Biomedical Engineering II for graduate students, 18.01.2022, Nakhon Pathom, Thailand

Permalink: https://www.hzdr.de/publications/Publ-34599
Publ.-Id: 34599


Radiomics-based differentiation of lung disease models generated by polluted air based on X-ray computed tomography data

Szigeti, K.; Szabó, T.; Korom, C.; Ilona, C.; Horváth, I.; Veres, D. S.; Gyöngyi, Z.; Karlinger, K.; Bergmann, R.; Pócsik, M.; Budán, F.; Máthé, D.

Background: Lung diseases (resulting from air pollution) require a widely accessible method for risk estimation and arly diagnosis to ensure proper and responsive treatment. Radiomics-based fractal dimension analysis of X-ray computed tomography attenuation patterns in chest voxels of mice exposed to different air polluting agents was performed to model early stages of disease and establish differential diagnosis.
Methods: To model different types of air pollution, BALBc/ByJ mouse groups were exposed to cigarette smoke combined with ozone, sulphur dioxide gas and a control group was established. Two weeks after exposure, the frequency distributions of image voxel attenuation data were evaluated. Specific cut-off ranges were defined to group voxels by attenuation. Cut-off ranges were binarized and their spatial pattern was associated with calculated fractal dimension, then abstracted by the fractal dimension – cut-off range mathematical function. Nonparametric
Kruskal-Wallis (KW) and Mann–Whitney post hoc (MWph) tests were used.
Results: Each cut-off range versus fractal dimension function plot was found to contain two distinctive Gaussian curves. The ratios of the Gaussian curve parameters are considerably significant and are statistically distinguishable within the three exposure groups.
Conclusions: A new radiomics evaluation method was established based on analysis of the fractal dimension of chest X-ray computed tomography data segments. The specific attenuation patterns calculated utilizing our method may diagnose and monitor certain lung diseases, such as chronic obstructive pulmonary disease (COPD), asthma, tuberculosis or lung carcinomas.

Keywords: Fractal dimension; Radiomics; In vivo micro-CT; Air pollution; Lung disease

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Permalink: https://www.hzdr.de/publications/Publ-34597
Publ.-Id: 34597


Euler-Euler / RANS Modeling of Solid-liquid Flow in Stirred Tanks: a Comprehensive Model Validation

Shi, P.; Sommer, A.-E.; Rox, H.; Eckert, K.; Rzehak, R.

Simulations of solid-liquid flow on industrial scales are feasible within the Euler-Euler / RANS approach. The reliability of this approach depends largely on the closure models applied to describe the unresolved phenomena at the particle scale, in particular the interfacial forces. In this work, a set of closure models assembled previously for this kind of application (Shi and Rzehak 2020) is further validated by comparing the predictions to a recent experiment on stirred-tank flows (Sommer et al. 2021), which focuses on dilute suspensions. The dataset used for validation comprises 14 different experimental cases, covering a wide range of particle slip Reynolds number, impeller Reynolds number, and particle Stokes number. For each case, simulation results on the solid velocity and volume fraction as well as liquid velocity and turbulence are compared with the experimental data. It turns out that by and large the experimental data are reasonably well reproduced. However, the measurements show a small but clear effect of modulation of the liquid phase turbulence by the particles. Therefore, several particle-induced turbulence (PIT) models based on the available literature are assessed as well. Our results indicate a reduction in the predicted fluctuations by all PIT models, which improves the results in cases with turbulence suppression but deteriorates those with turbulence augmentation.

Keywords: stirred tanks; solid-liquid flow; Euler-Euler two-fluid model; Reynolds-stress turbulence model; particle-induced turbulence

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Permalink: https://www.hzdr.de/publications/Publ-34596
Publ.-Id: 34596


Data: Temperature Driven Transformation of the Flexible Metal-Organic Framework DUT-8(Ni)

Ehrling, S.; Senkovska, I.; Efimova, A.; Bon, V.; Abylgazina, L.; Petkov, P.; Evans, J. D.; Elsherif, A. G. A.; Thomas Wharmby, M.; Roslova, M.; Huang, Z.; Tanaka, H.; Wagner, A.; Schmidt, P.; Kaskel, S.

These are the raw data of "Temperature Driven Transformation of the Flexible Metal-Organic Framework DUT-8(Ni)"  

DUT-8(Ni) metal-organic framework belongs to the family of flexible pillared layer materials. The desolvated framework can be obtained in the open pore form (op) or in the closed pore form (cp), depending on the crystal size regime. In the present work, we report on the behaviour of desolvated DUT-8(Ni) at elevated temperatures.
For both, op and cp variants, heating causes a structural transition, leading to an new, crystalline compound, containing two
interpenetrated networks. The state of the framework before transition (op vs. cp) influences the transition temperature: the small particles of the op phase transform at significantly lower temperature in comparison to the macroparticles of the cp phase, transforming close to the decomposition temperature. The new compound, confined closed pore phase (ccp), was characterized by powder X-ray diffraction and spectroscopic techniques, such as IR, EXAFS, and positron annihilation lifetime spectroscopy (PALS). Thermal effects of structural cp to ccp transitions were studied using differential scanning calorimetry (DSC), showing an overall exothermic effect of the process, involving bond breaking and reformation. Theoretical calculations reveal the energetics, driving the observed temperature induced phase transition.

Keywords: thermal response • interpenetrated MOF • thermal effect • phase transition • bond rearrangement

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Permalink: https://www.hzdr.de/publications/Publ-34595
Publ.-Id: 34595


The nature of π-hole interaction between iodide anion and quinoid ring in the crystalline state

Milašinović, V.; Vedran Vuković, V.; Krawczuk, A.; Krešimir Molčanov, K.; Hennig, C.; Bodensteiner, M.

Abstract The investigated co-crystal of 3-chloro-N-methylpyridinium iodide with tetrabromoquinone (3−Cl−N−MePy∙I∙Br4Q) reveals a π-hole interaction between an iodide anion and a quinoid ring involving a n→π* charge transfer. The quinoid ring has a partial negative charge (estimated to be in the range of 0.08 to 0.11 e) and a partial radical character, which is related to black colour of the crystals (the crystals of neutral tetrabromoquinone are yellow). A detailed X-ray charge density study revealed two symmetry-independent bonding critical points between the iodide and carbon atoms of the ring. Their maximum electron density of 0.065 e Å−3 was reproduced by quantum chemical modelling. Energy of the interaction is estimated to be −11.16 kcal mol−1, which is comparable to the strength of moderate hydrogen bonding (about −10 kcal mol−1); it is dominantly of electrostatic nature, with a considerable dispersion component.

Keywords: π-hole interactions; charge transfer; quinone; charge density; atoms-in-molecule

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Permalink: https://www.hzdr.de/publications/Publ-34594
Publ.-Id: 34594


Real-time Image Stream Algorithms - RISA

Windisch, D.; Bieberle, A.

Real-time image stream algorithms (RISA) is a high-throughput, low-latency image stream processing command-line application. Based on a configuration file, it will construct a processing pipeline of distinct processing steps and process a given image stream. Implementations of such processing steps are loaded from RISA-compatible shared libraries.

Keywords: Real-time; Image processing; Data processing; CUDA; C++

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  • Software in external data repository
    Publication year 2022
    Programming language: C++, CUDA
    System requirements: Linux-based operating system, CUDA-capable GPU
    License: Apache-2.0 (Link to license text)
    Hosted on https://gitlab.hzdr.de/risa/RISA: Link to location

Permalink: https://www.hzdr.de/publications/Publ-34593
Publ.-Id: 34593


Data: Fully encapsulated and stable black phosphorus field-effect transistors

Arora, H.; Fekri, Z.; Vekariya, Y. N.; Chava, P.; Watanabe, K.; Taniguchi, T.; Helm, M.; Erbe, A.

Fabricated devices went through electrical characterization with 4200-SCS parameter analyzer located in greyroom and Agilent 4156C Parameter Analyzer equipped with a cool-down setup located in 613. The measured data was processed with origin software.

Keywords: two-dimensional semiconductors; black phosphorus; field-effect transistors; hexagonal boron nitride; encapsulation

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Permalink: https://www.hzdr.de/publications/Publ-34592
Publ.-Id: 34592


Expanding the Range: AuCu Metal Aerogels from H2O and EtOH

Georgi, M.; Kresse, J.; Hiekel, K.; Hübner, R.; Eychmüller, A.

Due to their self-supporting and nanoparticulate structure, metal aerogels have emerged as excellent electrocatalysts, especially in the light of the shift to renewable energy cycles. While a large number of synthesis parameters have already been studied in depth, only superficial attention has been paid to the solvent. In order to investigate the influence of this parameter with respect to the gelation time, crystallinity, morphology, or porosity of metal gels, AuxCuy aerogels were prepared in water and ethanol. It was shown that although gelation in water leads to highly porous gels (60 m2g-1), a CuO phase forms during this process. The undesired oxide could be selectively removed using a post-washing step with formic acid. In contrast, the solvent change to EtOH led to a halving of the gelation time and the suppression of Cu oxidation. Thus, pure Cu aerogels were synthesized in addition to various bimetallic Au3X (X = Ni, Fe, Co) gels. The faster gelation, caused by the lower permittivity of EtOH, led to the formation of thicker gel strands, which resulted in a lower porosity of the AuxCuy aerogels. The advantage given by the solvent choice simplifies the preparation of metal aerogels and provides deeper knowledge about their gelation.

Keywords: metal; aerogel; gold; copper; ethanol; water; solvent; bimetallic; porous; one-step

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Permalink: https://www.hzdr.de/publications/Publ-34591
Publ.-Id: 34591


Bioleaching of metal(loid)s from sulfidic mine tailings and waste rock from the Neves Corvo mine, Portugal, by an acidophilic consortium

Opara, C. B.; Blannin, R.; Ebert, D.; Frenzel, M.; Pollmann, K.; Kutschke, S.

Sulfidic mine waste usually contains elevated amounts of valuable and hazardous metal(loid)s, which may pose environmental risks but can also provide opportunities for resource recovery. Reprocessing of mine waste can offer both economic and environmental benefits by supplying some of the ever-growing global demand for valuable metals, as well as reducing environmental risks. The present study aimed to simultaneously recover both valuable and hazardous metal(loid)s from two sulfidic mine waste samples (waste rock (NC_01) and tailings (NC_02)) from the Neves Corvo mine, Portugal, using a novel acidophilic consortium dominated by iron-oxidizing Leptospirillum genus and Acidiphilium sp. Bioleaching results showed that over 70% of the total Zn, Co, In, As, and Cd contents of NC_01 and NC_02 were leached within 21 days, while 55% – 62% Mn was leached. Copper behaved in a refractory manner, as only 33% and 21% Cu were leached from NC_01 and NC_02, respectively. X-ray diffraction (XRD) and Scanning electron microscope-based automated image analyses (SEM/MLA-GXMAP) of the bioleached residues revealed an almost complete absence of residual pyrite in NC_01 and a reduction of pyrite in NC-02, as well as the formation of secondary minerals, especially jarosite. In most cases, the biogenic jarosite co-precipitated some of the leached elements again, e.g., Cu and Pb. In conclusion, a synchronized method for bioleaching valuable and hazardous metal(loid)s was developed using a novel acidophilic consortium, thereby demonstrating the potential for the generation of economic value and environmental risk reduction for sulfidic mine waste samples.

Keywords: Bioleaching; Acidophiles; Metal(loid)s; Minerals; Sulfidic tailings; Sulfidic waste rock; SEM/MLA-GXMAP; XRD

Permalink: https://www.hzdr.de/publications/Publ-34590
Publ.-Id: 34590


Identification of geochemical and biological processes controlling naturally occurring radionuclides (NOR) mobility to derive more robust solid/liquid distribution coefficients (Kd)

Arnold, T.; Bok, F.; Cazala, C.; Coppin, F.; Fevrier, L.; Katz, A.; Krawczyk-Bärsch, E.; Landesman, C.; Mangeret, A.; Marsal, F.; Merroun, M. L.; Montavon, G.; Nivesse, A.-L.; Pelkonen, M.; Pérez-Sánchez, D.; Rigol, A.; Sachs, S.; Skipperud, L.; Urso, L.; Veilly, E.; Vidal, M.

Geochemical and biological processes controlling NOR mobility are studied within the RadoNorm project to derive more robust distribution coefficients Kd. To achieve this (i) the effect of microorganisms on NOR mobility in uranium (U) mine waters is studied, (ii) new datasets of NOR sorption and desorption parameters are acquired, (iii) a methodology for the determination of site-specific Kd values is evolved and (iv) models able to predict Kd (NOR) in relevant scenarios are developed.
The impact of microbes on the speciation of U in U mine waters is characterized by a multidisciplinary approach providing insights into the microbe/U interaction mechanisms needed to predict the effect of microbial processes on the mobility of this radionuclide.
Laboratory studies are performed to identify the soil properties that govern NOR interactions in soils. Sorption and desorption Kds for representative soils are determined, also considering soil aging effects. Chemical analogy between NOR and stable elements (e.g., Ba vs. Ra) is also examined, with new data and additional values gathered from literature.
Considering the dynamics of sorption-desorption reactions, studies are carried out at the Zatu site (France) to develop a method to determine site-specific Kds. Experiments with soil core samples are performed to determine the amount of desorbed U, Ra and Pb and to derive apparent Kd values. The validity of this approach will be confirmed combining these results with in situ studies (Zatu site).
Two approaches are followed to derive models for Kd (NOR) prediction. The first one is the “smart Kd” model, which is based on a realistic description of chemical reactions of NOR in liquid and solid phases. The second one is constructing simple, multivariate Kd prediction models based on soil properties governing NOR interaction. Water transport models with different levels of complexity are applied to describe the transport of NOR at the Zatu site in consistency with site-specific Kds.

Keywords: Naturally occurring radionuclides; NORM; Uranium; Radium; Sorption; Transport; Distribution coefficients; Modeling; Geochemical processes; Biological processes

  • Lecture (Conference)
    European Radiation Protection Week 2022, 09.-14.10.2022, Estoril, Portugal

Permalink: https://www.hzdr.de/publications/Publ-34589
Publ.-Id: 34589


(Data set) Optical study of RbV₃Sb₅: Multiple density-wave gaps and phonon anomalies

Wenzel, M.; Ortiz, B. R.; Wilson, S. D.; Dressel, M.; Tsirlin, A. A.; Uykur, E.

The folder contains the data set that the publication with the same name is based on. 

Origin file: 

  1. Reflectivity
  2. Optical conductivity
  3. Band resolved DFT calculation (band structure + optical conductivity)
  4. Comparison of DFT and experiment (interband transitions) above and below CDW transition
  5. Further data sets are available upon request

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Permalink: https://www.hzdr.de/publications/Publ-34588
Publ.-Id: 34588


Scaling Laser-Plasma Electron Accelerators to 100GeV-scale Energies using TWEAC and Multi-Petawatt Lasers

Debus, A.; Steiniger, K.; Schramm, U.

The quest for advanced acceleration techniques for providing more compact accelerators is a grand challenge of particle accelerator physics. Addressing this challenge will allow to further scale up energies for high-energy physics, as well as enable accelerator technology to be more commonly available.
Despite tremendous advances in Laser-Plasma accelerators (LPAs) with respect to beam energy, quality, charge and stability, sustaining scalability of compact LPAs to even higher electron energies and more brilliant secondary radiation sources is one of the yet to be solved key challenges of the field.
These limitations can be overcome by TWEAC (Traveling-Wave Electron ACceleration), a novel laser-plasma interaction geometry relying on spatio-temporally shaped ultrashort, high-power laser pulses using existing laser technology. These laser pulses provide "flying" focal regions propagating at tuneable velocities close to the speed of light without the need for external guiding.
Multi-petawatt laser facilities together with TWEAC pave the way towards scalable LPAs on the 100GeV scale without the need for multiple laser-accelerator stages.

Permalink: https://www.hzdr.de/publications/Publ-34587
Publ.-Id: 34587


Petawatt Class Lasers for Realizing Optical Free-Electron Lasers with Traveling-Wave Thomson-Scattering

Steiniger, K.; Debus, A.; Schramm, U.

Traveling-Wave Thomson-Scattering (TWTS) is a scheme for the realization of optical free-electron lasers (OFELs) from the interaction of ultra-short, high-power laser pulses with relativistic electrons.
The laser pulse thereby provides the undulator field which typically needs to include a few 100 to several 1000 undulator periods for OFEL operation.
Such long optical undulators are realized in TWTS by the combination of a side-scattering geometry where electron and laser pulse propagation directions enclose the interaction angle $\phi$ and a laser pulse-front tilt $\alpha_\A{tilt} = \phi/2$ of half the interaction angle.
This combination of side-scattering and pulse-front tilt ensures continuous overlap of electrons and laser pulse during the passage of the electrons through the laser pulse.
Interaction durations between laser pulse, electrons, and their emitted radiation can be long enough to initiate microbunching of the electron pulse and subsequent coherent amplification of radiation provided electron and laser pulse are of sufficient quality.
Requirements on electron and laser pulse quality can be met for VUV TWTS OFELs with existing technology already today and higher power laser pulses enable TWTS OFELs at shorter wavelength, e.\,g.\ EUV TWTS OFELs.

Permalink: https://www.hzdr.de/publications/Publ-34586
Publ.-Id: 34586


Atomically Dispersed Pentacoordinated-Zirconium Catalyst with Axial Oxygen Ligand for Oxygen Reduction Reaction

Wang, X.; An, Y.; Liu, L.; Fang, L.; Liu, Y.; Zhang, J.; Qi, H.; Li, T.; Heine, T.; Kuc, A. B.; Yu, M.; Feng, X.

Single-atom catalysts (SACs), affording extraordinary catalytic activity per site, represent promising alternatives to the commercial platinum-based electrocatalysts towards oxygen reduction reaction (ORR). Yet, the common in-plane coordination configuration limits platinum-competitive SACs to few transition metal elements with low metal loading (< 5 wt%). Here, we report the discovery of an ORR-efficient Zr-based SAC (denoted O-Zr-N-C), which consists of unique pentacoordinated Zr sites with nontrivial axial O ligands. The axial O ligand with the desirable electron-withdrawing effect downshifts the d-band center of Zr and confers single-atom Zr sites with stable local structure and proper adsorption capability for O-containing intermediates. Consequently, the ORR performance of O-Zr-N-C electrocatalyst in alkaline condition prominently surpasses that of commercial Pt/C, achieving a half-wave potential of 0.91 V vs. reversible hydrogen electrode, a kinetic current density of 76.0 mA cm–2, and outstanding durability (92% current retention after 130-hour operation). Moreover, the pentacoordinated Zr site shows good resistance towards aggregation, enabling the synthesis of O-Zr-N-C with high single atom Zr loading (9.1 wt%). With the high loading catalyst, the assembled zinc-air battery (ZAB) delivers a record-high power density of 324 mW cm−2 among those of SAC-based ZABs. This work not only provides a new member of ORR-active SACs, but also sheds light on the atomic-level design of advanced electrocatalysts.

Permalink: https://www.hzdr.de/publications/Publ-34585
Publ.-Id: 34585


Interlayer excitons in MoSe2/2D perovskite hybrid heterostructures – the interplay between charge and energy transfer

Karpińska, M.; Jasiński, J.; Kempt, R.; Ziegler, J. D.; Sansom, H.; Snaith, H. J.; Taniguchi, T.; Watanabe, K.; Surrente, A.; Dyksik, M.; Maude, D. K.; Kłopotowski, Ł.; Chernikov, A.; Kuc, A. B.; Baranowski, M.; Plochocka, P.

Van der Waals crystals have opened a new and exciting chapter in heterostructure research, removing lattice matching constraints characteristic of epitaxial semiconductors. They provide unprecedented flexibility for heterostructure design. Combining 2D perovskites with other 2D materials, in particular transition metal dichalcogenides (TMDs) has recently emerged as an intriguing way to design hybrid opto- electronic devices. However, the excitation transfer mechanism between the layers (charge or energy transfer) remains to be elucidated. Here we investigate PEA2PbI4/MoSe2 and (BA)2PbI4/MoSe2 heterostructures by combining optical spectroscopy and density functional theory (DFT) calculations. We show that the band alignment facilitates charge transfer. Namely, holes are transferred from the TMD to the 2D perovskite, while the electron transfer is blocked, resulting in the formation of inter-layer excitons. Moreover, we show that the energy transfer mechanism can be turned on by an appropriate alignment of the excitonic states, providing a rule of thumb for the deterministic control of the excitation transfer mechanism in TMD/2D-perovskite heterostructures.

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Permalink: https://www.hzdr.de/publications/Publ-34584
Publ.-Id: 34584


On the prospects of magnetic-field-assisted electrodeposition of nano-structured ferromagnetic layers

Huang, M.; Skibinska, K.; Zabinski, P.; Wojnicki, M.; Wloch, G.; Eckert, K.; Mutschke, G.

Micro- and nano-structured ferromagnetic layers are attractive for super-hydrophobic and electrocatalytic applications and can be effectively synthesized using electrodeposition. Beside the use of capping agents, magnetic fields have recently been proven to promote the growth of mm-sized conical structures by alternatively generating a supportive local flow. Here we explore the prospects of using magnetic fields to support the growth of smaller, micro-/nano-sized conical structures. We first elaborate by numerical simulations how the local electrolyte flow and the related inhomogeneous mass transfer change with shrinking cone size. Related scaling laws are derived, and stronger viscous friction along with smaller concentration changes inside the diffusion layer are found to limit the support of the magnetic field. To enhance the structuring effect, pulsed electrodeposition and use of superconducting magnets are discussed. Second, systematic experiments on the template-free electrodeposition of nickel layers in magnetic fields of different orientations and intensities are performed. Regardless of the direction, strong fields are found to promote blunt-ended, shell-like structures. These results are finally discussed by the help of numerical simulations which additionally consider the global cell flow forced by the magnetic fields. Importantly, global flow is found to dominate compared to local flow. We therefore propose improved electrode geometries for future research to clarify the prospects of stronger magnetic fields.

Keywords: ferromagnetic metal electrodeposition; magnetic field; nano-structured catalyst; numerical simulation; micro MHD effect

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Permalink: https://www.hzdr.de/publications/Publ-34582
Publ.-Id: 34582


Radiopharmazie des vergangenen Jahrzehnts

Steinbach, J.; Kopka, K.

Die Radiochemiker/Radiopharmazeuten des deutschsprachigen Raums sind im Verbund der AGRR – der „Arbeitsgemeinschaft Radiochemie und Radiopharmazie“ – innerhalb der Deutschen Gesellschaft für Nuklearmedizin organisiert. Die AGRR setzt sich vorrangig aus Kolleginnen und Kollegen der D-A-CH-Länder zusammen, sodass auf radiopharmazeutischer Seite eine Anbindung an die OGNMB und SGNM besteht. Sie pflegen dort – auch mit zahlreichen Mitgliedern aus der Industrie – während der jährlichen Arbeitstagungen einen intensiven Austausch, der über die Grenzen klassischer Vortragsveranstaltungen hinausgeht und so zu einer engen Vernetzung beiträgt. Neben klassisch-fachlichen Fragen bietet die AGRR eine Plattform zur Behandlung der vielen regulatorischen Probleme, die sowohl die pharmazeutischen als auch die Strahlenschutz-bezogenen Herausforderungen zur sicheren Versorgung der Nuklearmedizin mit anwendungsfertigen Radiopharmaka mit sich bringen.

Permalink: https://www.hzdr.de/publications/Publ-34581
Publ.-Id: 34581


Speciation and spatial distribution of Eu(III) in fungal mycelium

Günther, A.; Wollenberg, A.; Vogel, M.; Drobot, B.; Steudtner, R.; Freitag, L.; Hübner, R.; Stumpf, T.; Raff, J.

Europium, as an easy-to-study analog of the trivalent actinides, is of particular importance for studying the behavior of lanthanides and actinides in the environment. Since different soil organisms can influence the migration behavior of these elements, a detailed knowledge of these interaction mechanisms is important. The aim of this study was to investigate the interaction of mycelia of selected wood-inhabiting (S. commune, P. ostreatus, L. tigrinus) and soil-inhabiting fungi (L. naucinus) with Eu(III). In addition to determining the Eu(III) complexes in the sorption solution, the formed Eu(III) fungal species were characterized using scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy, chemical microscopy in combination with the time-resolved laser-induced fluorescence spectroscopy. Our data show that S. commune exhibited significantly higher Eu(III) binding capacity in comparison to the other fungi. Depending on fungal strain, the metal was immobilized on the cell surface, in the cell membranes, and within the membranes of various organelles, or in the cytoplasm in some cases. During the bioassociation process two different Eu(III) fungal species were formed in all investigated fungal strain. The phosphate groups of organic ligands were identified as being important functional groups to bind Eu(III) and thus immobilize the metal in the fungal matrix. The information obtained contributes to a better understanding of the role of fungi in migration, removal or retention mechanisms of rare earth elements and trivalent actinides in the environment.

Keywords: Fungi; Europium; Speciation; Scanning transmission electron microscopy (STEM); Chemical microscopy; Time-resolved laser-induced fluorescence spectroscopy (TRLFS)

Permalink: https://www.hzdr.de/publications/Publ-34580
Publ.-Id: 34580


Coupling between ferromagnetic and ferroelastic transitions and ordering in Heusler alloys produces new multifunctionality

Oleg, H.; Hanuš, S.; Fähler, S.

The ability of Heusler alloys to accommodate broad variations of composition, doping
and ordering provides multiple options for tailoring their ferromagnetic and ferroelastic
properties. Moreover, existing coupling between these ferroic properties ranging from
coupled ferroic transitions to a coupling of their ferromagnetic and ferroelastic
microstructure allows for manifold multifunctionalities. Here we focus on ferromagnetic,
metamagnetic and reentrant shape memory alloys explaining the principles and sketch
effects’ rich susceptibility to temperature, magnetic field and stress. We illustrate how
these can provide a path to a multitude of emerging applications for actuation, sensing,
and energy use. As an outlook, we discuss time dependency, fatigue, and finite size
effects, which are not yet fully explored.

Keywords: Heusler Alloys; Functional magnetic materials; Magnetic shape memory alloys

Permalink: https://www.hzdr.de/publications/Publ-34579
Publ.-Id: 34579


New concepts for recovery of metals from wastes using biological means

Pollmann, K.; Lederer, F.; Schönberger, N.; Jain, R.; Chakankar, M. V.; Kutschke, S.

The development of new technologies, especially in the field of renewable energies, has led to an increase in the demand for essential metals in recent years. At the same time, the extraction of these metals is not always environmentally friendly. Toxic metals can pollute waters and enter the environment both during extraction and processing or through disposal. Therefore, new environmentally friendly technologies are needed that prevent their entry into the environment or efficiently contribute to the recovery and recycling of the elements. Biotechnology can contribute to this.
Such technologies exploit the natural ability of organisms, bio-components, and biomolecules to interact with metals. Furthermore, modern methods of molecular biology and synthetic biology enable the development of tailored biomolecules that interact with metal ions or surfaces. In this talk, some of these modern biotechnological concepts for metal extraction such as bioleaching, bioflotation, biosorption from various primary and secondary raw materials as well as for treatment of metal contaminated waste waters will be presented.

  • Lecture (Conference) (Online presentation)
    ACS Spring 2022, 20.-24.03.2022, San Diego, CA, USA

Permalink: https://www.hzdr.de/publications/Publ-34578
Publ.-Id: 34578


Temperature Driven Transformation of the Flexible Metal-Organic Framework DUT-8(Ni)

Ehrling, S.; Senkovska, I.; Efimova, A.; Bon, V.; Abylgazina, L.; Petkov, P.; Evans, J. D.; Attallah, A. G.; Thomas Wharmby, M.; Roslova, M.; Huang, Z.; Tanaka, H.; Wagner, A.; Schmidt, P.; Kaskel, S.

DUT-8(Ni) belongs to the flexible pillared layer MOFs, which solvent free variant can exist in the open pore (op, rigid) form or in the closed pore (cp, flexible) form depending on the crystal size regime. In present work, we report on response of desolvated DUT-8(Ni) against elevated temperature. For both variants, heating leads to structural transition, involving interpenetration of the framework and resulting in a new crystalline contracted closed pore phase (DUT-8(Ni)_ccp). The new compound was characterized by powder X-ray diffraction and spectroscopic techniques, such as IR, Raman spectroscopy, EXAFS and positron annihilation lifetime spectroscopy (PALS). State of the framework before transition (op vs. cp) influences the transition temperature: the small particles of the op phase transform at significantly lower temperature in comparison to the macroparticles of the cp phase, transforming just before decomposition. Thermal effects of structural cp to ccp transitions were studied using differential scanning calorimetry (DSC), showing an overall exothermic effect of the process, necessarily involving bond breaking and reformation. The theoretical calculations reveal the energetics driving the observed temperature induced phase transition.

Keywords: bond rearrangement; nterpenetrated MOF; hase transitio; thermal response; hermally-induced phase transformation

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Permalink: https://www.hzdr.de/publications/Publ-34575
Publ.-Id: 34575


Atherosclerotic risk is associated with cerebral perfusion – a cross-sectional study using arterial spin labelling MRI

Hafdi, M.; Mutsaerts, H. J.; Petr, J.; Richard, E.; van Dalen, J. W.

Non-invasive measurement of cerebral perfusion is promising for identifying individuals at high risk of cerebrovascular disease for prevention strategies. We tested whether the new and easily calculated arterial spin labelling (ASL) MRI parameter for vascular and tissue signal distribution - ‘spatial coefficient of variation’ (ASL-sCoV) - correlates better as a radiological marker with atherosclerotic risk than the more courant markers white matter hyperintensity volume (WMHV) and cerebral blood flow (CBF).
Methods
195 participants of the preDIVA trial, aged 72-80 years with systolic hypertension (>140 mmHg) were invited for 2 MRI-scans 2-3 years apart. WMHV was derived from 3D FLAIR; grey matter CBF and ASL-sCoV from ASL. The ASL-sCoV was defined as the standard deviation of CBF divided by the mean CBF in the entire region of interest. Atherosclerotic risk was operationalized as 10-year cardiovascular risk by the Systematic COronary Risk Evaluation Older Persons (SCORE O.P.) and calculated at baseline and follow-up. Data were analysed using linear regression.
Results
CBF was associated with atherosclerotic risk scores at baseline (standardized-beta=-0.26, 95%CI=-0.40,-0.13, p<0.001) but not on follow-up (standardized-beta=-0.14, 95%CI=-0.33,0.04, p=0.12). ASL-sCoV was associated with atherosclerotic risk scores at both time points (baseline standardized-beta=0.23, 95%CI=0.10,0.36, p<0.0001, follow-up standardized beta= 0.20, 95%CI=0.03,0.36, p=0.02). WMHV was not significantly associated with atherosclerotic risk scores at either time-points (p>0.25). There were no longitudinal associations between changes in MRI parameters and baseline atherosclerotic risk scores. Imputation of missing values, exclusion of outliers, and repeating analyses using the Framingham- and ASCVD risk scores instead of the SCORE O.P. gave similar results.
Conclusions
Our findings suggest that ASL-sCoV correlates better with atherosclerotic risk than the more conventional markers CBF and WMHV. Our data reaffirm that non-invasive imaging with MRI is highly informative and could provide additional information about the (cerebro)vascular status, especially in participants in whom early prevention of atherosclerosis and cardiovascular disease might still be attainable.

Permalink: https://www.hzdr.de/publications/Publ-34573
Publ.-Id: 34573


Mitigating pseudoreplication and bias in resource selection functions with autocorrelation-informed weighting

Alston, J.; Fleming, C.; Kays, R.; Streicher, J.; Downs, C.; Ramesh, T.; Reineking, B.; Calabrese, J.

Resource selection functions are among the most commonly used statistical tools in both basic and applied animal ecology. They are typically parameterized using animal tracking data, and advances in animal tracking technology have led to increasing levels of autocorrelation between locations in such data sets. Because resource selection functions assume that data are independent and identically distributed, such autocorrelation can cause misleadingly narrow confidence intervals and biased parameter estimates. Data thinning, generalized estimating equations, and step selection functions have been suggested as techniques for mitigating the statistical problems posed by autocorrelation, but these approaches have notable limitations that include statistical inefficiency, unclear or arbitrary targets for adequate levels of statistical independence, constraints in input data, and (in the case of step selection functions) scale-dependent inference. To remedy these problems, we introduce a method for likelihood weighting of animal locations to mitigate the negative consequences of autocorrelation on resource selection functions. This method weights each observed location in an animal's movement track according to its level of autocorrelation, expanding confidence intervals to match an objective target (i.e., the effective sample size for Autocorrelated Gaussian Density Estimation) and accounting for bias that can arise when there are gaps in the movement track. In this study, we describe the mathematical principles underlying our method, demonstrate its practical advantages versus conventional approaches using simulations and empirical data on a water mongoose (\textit{Atilax paludinosus}), a caracal (\textit{Caracal caracal}), and a serval (\textit{Leptailurus serval}), and discuss pathways for further development of our method. We also provide a complete, annotated analytical workflow to help new users apply our method to their own animal tracking data using the \texttt{ctmm R} package.

Keywords: continuous-time movement models; habitat selection; home range; Ornstein-Uhlenbeck process; space use; spatial point process; utilization distribution

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Permalink: https://www.hzdr.de/publications/Publ-34572
Publ.-Id: 34572


alpaka-group/alpaka: alpaka 0.9.0: The SYCL Complex

Bastrakov, S.; Bocci, A.; Di Pilato, A.; Ehrig, S.; Gruber, B. M.; Hübl, A.; Kelling, J.; Pantaleo, F.; Stephan, J.; Vyskocil, J.; Widera, R.; Worpitz, B.

The alpaka library is a header-only C++17 abstraction library for accelerator development. Its aim is to provide performance portability across accelerators through the abstraction (not hiding!) of the underlying levels of parallelism.

Keywords: CUDA; HPC; alpaka; OpenMP; HIP; C++; GPU; heterogeneous computing; performance portability; FPGA; SYCL

  • Software in external data repository
    Publication year 2022
    Programming language: C++
    System requirements: OS: Linux, Windows, or macOS Software requirements: C++17 compiler, Boost 1.74.0+, CMake 3.18+
    License: MPL-2.0 (Link to license text)
    Hosted on GitHub: Link to location
    DOI: 10.5281/zenodo.6475608

Permalink: https://www.hzdr.de/publications/Publ-34571
Publ.-Id: 34571


Quantifying the impact of cross-border flux on disease dynamics

Senapati, A.; Calabrese, J.

Countries all over the world have implemented various cross-border policies such as mandatory testing, quarantining upon arrival, and travel restrictions to minimize the risk of infection. The strength of these measures has varied over time. The aim of this study is twofold. First, we develop a spatially explicit SIR-type mechanistic model to assess the epidemiological consequences of allowing cross-border mobility between two countries under different epidemic conditions. We show that the time to achieve the peak of infection is significantly changed if cross-border mobility is allowed during disease outbreak. Moreover, if we compare between the scenarios with and without cross-border flux, the difference in peak timings in two countries is reduced in the latter case. Next, based on stochastic simulation, we present a method for estimating cross-border mobility flux between two regions from the difference in peak-timing in infection under some reasonable assumptions. As a case study, we apply the method to data from the Germany-Poland border region and quantify heterogeneity in cross-border fluxes along the border during the COVID-19 pandemic.

Keywords: COVID-19; Infectious disease; Mathematical Modelling; Cross-border mobility; Compartmental modelling

  • Open Access Logo Lecture (Conference)
    Models in Population Dynamics, Ecology and Evolution (MPDEE 2022), 13.-17.06.2022, Torino, Italy

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Permalink: https://www.hzdr.de/publications/Publ-34569
Publ.-Id: 34569


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