Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

The surface microbubbles (SMBs) induced by air nucleation on mineral surfaces exert a powerful influence over enhancing the adhesion of air bubbles or oil droplets on mineral surfaces in flotation. The contact angles and TPLs were characterized by captive-bubble/oil droplet on the graphite surfaces. They were combined with dynamic bubble/oil droplet-graphite surface attachment and detachment visualization and force measurements using a microbalance system equipped with a camera to demonstrate the role of SMBs in bubble/oil dropletgraphite surface adhesion. The results show that after depressurization, the dissolved air in water nucleates on both hydrophobic and oxidized graphite surfaces, resulting in SMBs formation, which can enhance the adhesion of bubbles/oil droplets with the different graphite surfaces. For bubble-solid adhesion, these enhancements are attributed to the bridging effect of the SMBs coalescing with the large bubble increasing threephrase contact lines (TPLs) and with this the adhesion forces. For oil-solid interactions, SMBs induce the attachment and spreading of the oil droplet on the graphite surfaces, as the TPLs and spreading forces are increased. SMBs also result in a more stable oil droplet-graphite interface, as the adhesion forces are improved. Therefore, SMBs are efficient for improving graphite flotation by increasing the stability of the mineralized bubble and promoting the spreading and adhesion of dodecane oil. Hence, SMBs coupled with the modification of the surface hydrophobicity may be more beneficial for flotation separation.

Nanofibrillated cellulose (NFC) has presented great potential as supports for functional membrane materials owing to its unique advantages. In this work, NFC-supported MOF hierarchically porous membranes were synthesized by anchoring HKUST-1 (copper 1,3,5-benzenetricarboxylate open-framework) on NFC membrane through a green DMF-free (N,N-Dimethylformamide) method at room temperature and afterward, the as-prepared composite membrane was used to remove formaldehyde from the air. The addition of HKUST-1 particles significantly increased the specific surface area of NFC membrane without affecting the NFC properties. Meanwhile, the nucleation and growth process of HKUST-1 on the NFC membrane could be effectively regulated, which further controlled the morphology of HKUST-1 as well as the anchored position of HKUST-1. When HKUST-1 was anchored on the interior and surface of the membrane, HKUST-1 reduced the compactness of the arrangement between fibers, which resulted in a hierarchical porous structure and then exposed more active adsorption sites of HKUST-1 particles. Thus, the flexible composite membranes exhibited effective formaldehyde adsorption from a low formaldehyde concentration environment (3.0 mg/m3). Under the optimum conditions, the maximum adsorption capacity of the HKUST-1@NFC-1 for formaldehyde reached 378.09 mg/g (based on HKUST-1 wt), which was considerably higher than support-free HKUST-1 powders. Consequently, the present work offers a green and controllable route to prepare NFC-supported MOF composite membranes with highly effective formaldehyde adsorption capacity and thus provides a promising option for NFC application as a flexible adsorbent support.

Lignin reductive depolymerization into phenolic monomers is a critical step for the scale-conversion of lignin into liquid fuels but its scale-up is still compromised by harsh reaction conditions (e.g. high temperature and high external H2 pressure) and inevitable condensations. Herein, we present an efficient acid-promoted reductive depolymerization of lignin over Ni/C without external H2 via a condensation minimizing approach using lignin monomer analogue (p-hydroxybenzyl alcohol, HBA) as the capping agent. With addition of 0.4 % H2SO4 and 0.4 mmol/g HBA, 20.42 % of phenolic monomer yield along with 31.70 % oligomer yield was achieved at 160 °C while the condensated/undepolymerized lignin yield was less than 10 %. HBA inhibited the acid-induced condensation by competitive reaction with the nucleophilic C6 in guaiacyl unit. When the approach was applied in lignin-first reductive fractionation of poplar, 32.72 % of phenolic monomer yield and 76.59 % of delignification were achieved at 160 °C in the presence of acid and HBA. Additionally, xylan was dissociated concurrently owing to the acid-catalyzed hydrolysis, resulting in a cellulose-rich solid residue. Consequently, this work proposes an efficient approach for lignin reductive depolymerization and lignin-first biomass fractionation under mild conditions through the synergism of acid and capping agent.

High precision measurements of flow coefficients vn (n=1−4) for protons, deuterons and tritons relative to the first-order spectator plane have been performed in Au+Au collisions at √sNN=2.4 GeV with the High-Acceptance Di-Electron Spectrometer (HADES) at the SIS18/GSI. Flow coefficients are studied as a function of transverse momentum pt and rapidity ycm over a large region of phase space and for several classes of collision centrality. A clear mass hierarchy is found for the slope of v1, dv1/dy′|y′=0 where y′ is the scaled rapidity, and for v2 at mid-rapidity. Scaling with the number of nucleons is observed for the pt dependence of v2 and v4 at mid-rapidity, which is indicative for nuclear coalescence as the main process responsible for light nuclei formation. v2 is found to scale with the initial eccentricity ⟨ϵ2⟩, while v4 scales with ⟨ϵ2⟩2 and ⟨ϵ4⟩. The multi-differential high-precision data on v1, v2, v3, and v4 provides important constraints on the equation-of-state of compressed baryonic matter.

First information on the timelike electromagnetic structure of baryons in the second resonance region has been obtained from measurements of invariant mass and angular distributions in the quasi-free reaction π−p→nee at sπ−p−−−−√ = 1.49 GeV with the High Acceptance Di-Electron Spectrometer (HADES) detector at GSI using the pion beam impinging on a CH2 target. We find a total cross section σ(π−p→nee)=2.97±0.07data±0.21acc±0.31Zeffμb. Combined with the Partial Wave Analysis of the concurrently measured two-pion channel, these data sets provide a crucial test of Vector Meson Dominance (VMD) inspired models. The commonly used "strict VMD" approach strongly overestimates the e+e− yield. Instead, approaches based on a VMD amplitude vanishing at small e+e− invariant masses supplemented coherently by a direct photon amplitude provide a better agreement. A good description of the data is also obtained using a calculation of electromagnetic timelike baryon transition form factors in a covariant spectator-quark model, demonstrating the dominance of meson cloud effects. The angular distributions of e+e− pairs demonstrate the contributions of virtual photons with longitudinal polarization, in contrast to real photons. The virtual photon angular dependence supports the dominance of J=3/2, I=1/2 contributions observed in both the γ⋆n and the ππn channels.

I give an introduction to the application of deep neural networks for the surrogate modelling of electron--electron correlations in warm dense matter theory.

In March 2019 the HADES experiment recorded 14 billion Ag+Ag collisions at √sNN = 2.55 GeV as a part of the FAIR phase-0 physics program. In this contribution, we present and investigate our capabilities to reconstruct and analyze weakly decaying strange hadrons and hypernuclei emerging from these collisions. The focus is put on measuring the mean lifetimes of these particles.

Low-permeability granites are considered as host rocks for nuclear waste repositories. Understanding fluid flow and solute transport in granite fractures are essential in assessing the feasibility and safety of a nuclear waste repository. The internal variability of fractures, such as aperture distribution and asperities, dictates the hydrodynamics of reactive fluid, thus affecting the dispersion and retention of radionuclides. Numerical studies using 2-D models have focused on the heterogeneity of aperture distribution, but the effects of fracture asperities and additional surface features on the evolution of flow paths have not been systematically examined. In this study, the nonreactive solute transport behavior in a single fracture was numerically investigated considering the effects of fracture aperture and surface asperity by comparing 2.5-D and 3-D modeling results on a realistic fracture. The additional motivation here was to identify the limitations of model simplification. The 3-D fracture geometry was extracted from a micro-computed tomography of a natural fracture several centimeters long. Then, 2.5-D models were generated by mapping the aperture distribution of the 2-D fracture geometry on the x-y plane. Flow simulations were performed in both numerical models to detect the respective effects of fracture shape and surface asperities. For validation, we performed a sensitivity analysis by decreasing the 3-D fracture geometry mesh according to the quadric edge-collapse strategy, simulating the solute transport behavior under different fracture surface properties. The size variability of the isometric grid blocks ranges from 6.5 µm to 2.2 mm. Thus, we provide a function that can be used to quantitatively estimate the concentration error due to the simplification of the geometry mesh. The results show which fracture asperities and surface properties can significantly affect the solute transport behavior. Above a certain geometry complexity, the 3-D model results show less retention in the rather stagnant zones and thus better agreement with breakthrough curves (BTCs) of experiments compared to the 2.5-D model approaches. The results of the 3-D models also agree well with previous studies that less pronounced tailing is observed in the case of lower surface roughness. Simplifying the model geometry leads to more distorted results, with the 3-D model being more sensitive than the 2.5-D model. Moreover, based on a function summarized from the BTCs, the error in the simulated concentration due to mesh simplification can be estimated within a certain range that varies with the fracture geometry. The results presented show the capabilities and limitations of using 2.5D models in comparison with more elaborate 3-D models in predicting fluid dispersion in fractured crystalline rocks. Our study can serve as a guideline for the construction of fracture geometry and model design in future reactive transport modeling.

The global polarization of Λ hyperons along the total orbital angular momentum of a relativistic heavy-ion collision is presented based on the high statistics data samples collected in Au+Au collisions at sqr(SNN)=2.4 GeV and Ag+Ag at 2.55 GeV with the High-Acceptance Di-Electron Spectrometer (HADES) at GSI, Darmstadt. This is the first measurement below the strangeness production threshold in nucleon-nucleon collisions. Results are reported as a function of the collision centrality as well as a function of the hyperon's transverse momentum () and rapidity () for the range of centrality 0–40%. We observe a strong centrality dependence of the polarization with an increasing signal towards peripheral collisions. For mid-central (20 – 40%) collisions the polarization magnitudes are (PΛ)(%) = 6.8 ± 1.3 (stat.) ±
2.1 (syst.) for Au+Au and (PΛ)(%) = 6.2 ± 0.4 (stat.) ± 0.6 (syst.) for Ag+Ag, which are the largest values observed so far. This observation thus provides a continuation of the increasing trend previously observed by STAR and contrasts expectations from recent theoretical calculations predicting a maximum in the region of collision energies about 3 GeV. The observed polarization is of a similar magnitude as predicted by 3D-fluid-dynamics and the UrQMD plus thermal vorticity model and significantly above results from the AMPT model.

Laser-driven plasma accelerators (LPA) are compact sources of ultra-short, intense proton pulses in the multi-10-MeV energy range. These unique parameters predestine LPAs as powerful tools for ultra-high dose rate radiobiology research. The sources’ capabilities were recently demonstrated in the first successful small animal pilot study on radiation-induced tumor growth delay in mice using an LPA proton source [1].
To promote further sophisticated radiobiological studies at LPAs, adapted approaches for primary LPA source characterization, beam monitoring and dosimeters are required. Here, most prominent challenges are LPA-inherent pulse-to-pulse fluctuation in terms of intensity as well as proton energy distribution, the ultra-high pulse dose rate and the harsh plasma environment, featuring a strong electromagnetic pulse (EMP) and an intense mixed radiation background. These conditions call for robust online monitoring solutions.
We present the solutions for source-to-sample characterization implemented at the ALBUS-2S beamline [2] at the Draco Petawatt laser system [3] at Helmholtz-Zentrum Dresden-Rossendorf. These include firstly an online beam monitoring system based on a time-of-flight spectrometer (ToF BMS). A core feature of the ToF BMS method is a precise spectrum-based forward-calculation of the corresponding volumetric dose distribution via Monte-Carlo simulation. Secondly, a dosimetric system for volumetric mm-scale sample irradiations was conceptualized and tested during an in vivo irradiation study, showing a solution for precise dosimetric characterization of ultra-high dose rate pulses at the ~500 mGy pulse dose range.
Lastly, with the OCTOPOD and MiniSCIDOM, two devices for online, single pulse characterization of volumetric dose distributions are presented, applicable for the primary LPA source and mm-scale dose distributions at the sample site, respectively. Both devices are based on volumetric scintillators as active detector material and rely on tomographic reconstruction for signal retrieval.

[1] F. Kroll, et al., Tumour irradiation in mice with a laser-accelerated proton beam, Nat Phys, 18, (2022), 316.
[2] F.-E. Brack, et al., Spectral and spatial shaping of laser-driven proton beams using a pulsed high-field magnet beamline, Sci Rep, 10, (2020), 9118.
[3] U. Schramm, et al., First results with the novel petawatt laser acceleration facility in Dresden, J. Physics: Conf. Ser, 874, (2017), 012028.

Here we demonstrate how a peptide-based material can be obtained for the biosorptive recovery of metals from contaminated industrial wastewater, starting with Phage surface display for the initial identification and optimization of gallium-binding peptides.
Two chromatography-based biopanning methods for the identification of gallium-binding peptides from a commercial phage display library were developed. Five gallium-binding peptide sequences were identified and evaluated to show good gallium-binding properties.
Furthermore, the biosorption of free gallium and arsenic by gallium-binding bacteriophage clones was investigated. A large influence of the pH-value on the respective interactions was demonstrated.
Mutagenesis experiments were also carried out for a bacteriophage clone expressed peptide, in which a cysteine pair systematically replaced amino acids. Biosorption experiments with the resulting seven different bacteriophage mutants suggested a relationship between the rigidity of the peptide structure and the gallium-binding properties.
In isothermal titration experiments, the thermodynamics of the interaction between gallium and the peptides as chemically synthesized derivatives were characterized, independent of the bacteriophage. The peptides differed strongly in their interaction with gallium, and in some cases, the complex formation with gallium depended strongly on the surrounding buffer conditions.
The peptide with the amino acid sequence NYLPHQSSSPSR has particularly promising gallium-binding properties. Computer modeling suggests the probable structure of the peptide in aqueous solution and postulates a possible binding site for gallium.
The side-selective and covalent immobilization of the peptides on a polystyrene matrix led to the creation of a biocomposite for the biosorptive recovery of gallium. The sorption performance and desorbability of the peptide-based biosorption materials were determined in studies with model solutions and real waters from the semiconductor industry.
 

Laser-plasma based proton accelerators as a novel accelerator technology have matured to a level at which laboratory-scale setups for the emerging topic of image-guided precision small animal irradiation studies come into reach [Bra2019]. Providing a high proton energy bandwidth [Sch2016] which is filtered in a tunable pulsed magnet beam transport, these accelerators enable flexibility in terms of scattering-free irradiation field formation [Mas2014, Mas2015]. Regarding temporal dose delivery, with single pulse doses reaching the Gy level at unprecedented peak dose rates of up to 1012 Gy/s [Sch2016], laser-plasma based proton accelerator setups can give access to the dose rate regime of FLASH [Fav2014, Voz2019].
The realization of a full-scale setup for image-guided precision radiobiological studies for small animals focusing on dose rate dependent effects is currently prepared at the PENELOPE laser-plasma based proton accelerator at HZDR and will be presented with a focus on the technological requirements and solutions for dose delivery at laser-plasma based sources.
This development relies on our experience in performing dose-controlled radiobiological in vitro studies [Kra2010, Zei2013] and first in vivo irradiation experiments at the DRACO laser-plasma based proton accelerator at HZDR, where we have established a pulsed solenoid beamline for 3D irradiation field formation, yielding a (5 mm)³ homogeneous volumetric dose distribution at a Gy single pulse dose level [8].
[Bra2019] F.-E. Brack, F. Kroll, L. Gaus, C. Bernert, E. Beyreuther, T. E. Cowan, L. Karsch, S. D. Kraft, L. A. Kunz-Schughart, E. Lessmann, J. Metzkes-Ng, L. Obst-Hübl, J. Pawelke, M. Rehwald, H.-P. Schlenvoigt, U. Schramm, M. Sobiella, E. R. Szabó, T. Ziegler, K. Zeil, Spectral and spatial shaping of laser-driven proton beams using a pulsed high-field magnet beamline. arXiv:1910.08430 (2019)
[Sch2016] J. Schreiber, P. Bolton, K. Parodi, “Hands-on” laser-driven ion acceleration: A primer for laser-driven source development and potential applications, Rev. Sci. Instr. 87, 071101 (2016)

Most approaches to implant single or few ions for quantum applications require the use of focused ion beams (FIB). In addition to the detection of ion implantation and laterally precise placement, the first consideration should also be the species as well as the emittance of the ion beam itself. While elements that are gaseous at room temperature can mainly provided by Gas Field Ion Sources or Plasma Ion Sources, most of the metals and semimetals afford the utilization of Liquid Metal Ion Sources (LMIS).

Gallium has established in industry and science as easiest and most stable type of LMIS. For quantum applications other ion species like Li, B, C, N, Al, Si, P, Sb, Bi or the rare earth elements became from higher interest [1-6]. We give an overview about published metal alloys for FIBs and give an insight into the development and production of new sources. Finally, we give an outlook on current and future applications and activities.

[1] L. Bischoff, et al., Micro Eng. 13, 367 (1991), 10.1016/0167-9317(91)90113-R
[2] P. Mazarov, et al., JVST B 27, L47-L49 (2009), 10.1116/1.3253471
[3] L. Bischoff, et al., Appl. Phys. Rev. 3, 021101 (2016), 10.1063/1.4947095
[4] W. Pilz, et al., JVST B 37, 021802 (2019), 10.1116/1.5086271
[5] L. Bischoff, et al., JVST B 38, 042801 (2020), 10.1116/6.0000073
[6] N. Klingner, et al., BJNANO 11, 1742 (2020), 10.3762/bjnano.11.156

Broad ion beams have shown their wide applications for materials modification. Focused ion beams can be used in a similar way while simultaneously providing process monitoring. Here, we demonstrate this on a new kind of ion-induced structural evolution.

Sub-micrometer Sn spheres were irradiated in a helium ion microscope with a sub-nm beam of 30 keV He ions. Above a fluence of ~10^17/cm², Sn extrusions appeared on the surface of the spheres, which were imaged using the secondary electron signal. Initially, small, pyramid-like faceted extrusions form at the equator of the spheres (north pole pointing to the ion source). Later, each sphere becomes completely covered by the extrusions.

A model was developed that assumes that each He ion generate ~70 Frenkel pairs. The implanted helium atoms, interstitials, and vacancies will be confined by the oxide skin of the spheres. Some He atoms will occupy vacancies, which partially prevent their recombination with interstitials. Furthermore, the ion irradiation leads to erosion and opening of the SnO skin. The interstitials can now escape from the interior of the Sn sphere and form an epitaxial regular Sn lattice on the exterior.

Transmission electron microscopy, Auger electron spectroscopy as well as TRI3DYN [1] and 3D kinetic lattice Monte Carlo [2] simulations support these findings.

In addition, we provide a perspective on focused ion beams from our in-house development and production of liquid metal alloy ion sources, which can be used for applications from self-organized patterning, over altering magnetic or electrical properties, to quantum photonics and computation [3].

[1] Möller, Nucl. Instr. Meth. B 322 (2014) 23
[2] Strobel et al., Phys. Rev. B 64 (2001) 245422
[3] www.hzdr.de/fib

This work focuses on the identification and characterization of inorganic-binding peptidic biomolecules for resource recovery. Manifold biological molecules are used in pharmaceutical and nutrition industries but have so far only limited use in resource technology. Geopolitical tensions, decreasing ore grades combined with increasing demand due to the development of new products and markets result in resource scarcity and the need for new (green) innovative recycling and recovery technologies. Here, we present a novel approach for the design and construction of tailor-made selective target-specific proteinaceous molecules for the creation of innovative bio-based resource recovery applications. Novel peptides with high affinity towards minerals, metals and metalloids such as cobalt, nickel, gallium, arsenic and recently plastics have been identified in our working group using directed evolution phage display technology based on large peptide libraries. Until recently, identification of novel peptides was solely based on ten to hundreds of sequences out of libraries consisting of billions of peptides. As of late, next-generation sequencing (NGS) high throughput analysis of phage display libraries allowed for unprecedented insight into said libraries and accelerated identification of target-specific molecules. Here, we present the NGS-guided phage display-based identification of novel metal- and plastic-binding peptides for surface modification including new findings to the underlying selection process. The characterization of said sequences was successfully achieved in nanomolar ranges with solution- and surface interaction technologies such as isothermal titration calorimetry and quartz crystal microbalance with dissipation monitoring. The here presented results and approaches indicate possibilities for the design and the future provision of innovative bio-based recovery and recycling processes.

Nowadays, great efforts have been spent on addressing concerns over energy and environmental crises. Among these efforts, electrocatalysis is widely recognized and studied for its high efficiency and easy processability. As a class of emerging electrocatalysts, metal aerogels (MAs) stand out in the last decade. In virtue of their three‐dimensional conductive pathways, their library of catalytically/optically active sites, and their robust network structures, MAs have unique advantages in electrocatalysis. However, due to the short history of MAs, there is insufficient research on them, leaving significant room for material design and performance optimization. This perspective will mainly focus on electrocatalysis with MAs, aiming to summarize the state‐of‐the‐art progress and to guide the on‐target design of efficient MAs‐based electrocatalysts towards energy‐ and environment‐related applications.

GaLIOphore technology for Metal Recovery from Primary and Secondary Resources

Recovery of critical metals from the low concentrated wastewater and wastes

Biotechnology for the recovery of germanium, indium and copper from industrial copper dust waste

Background:Internal carotid-artery stenosis (ICAS)accounts for approximately 10–20% of all strokes.1While effective endovascular treatment is available bycarotid artery stenting (CAS) or carotid endarterectomy(CEA), they come with substantial risks.2Those compet-ing risks complicate treatment decisions especially inasymptomatic ICAS and create the need for improvedpostoperative outcome evaluations. Moreover, revascular-ization effects on cognitive impairments are widelyunknown.3Aim:This MRI-study evaluated endovascular treatmentefficacy in asymptomatic ICAS by clinically applicablehemodynamic imaging. We evaluated capillarytransit-time heterogeneity (CTH) and relative cerebralblood volume (rCBV) with additional visual attentiontesting.Method:16 asymptomatic unilateral high-grade ICAS-patients (age 71.4>5.8y) and 17 age-matched healthycontrols (HC,age 70.8>5.3y) underwent MRI on a 3TPhilips Ingenia twice (10.5 months mean follow-up time).White matter lesions (WML) were derived from FLAIR,4CTH and rCBV from dynamic susceptibility contrast5andtheir lateralization compared within grey matter of themiddle cerebral arterial circulation.6Cognitive testingwith inter-hemispheric sensitivity was based on thetheory of visual attention.7Results/Conclusions:Ipsilateral increases of CTH byþ21.4% (p<0.01, Figure 1(a)) and rCBV byþ4.3%(p<0.03, Figure 1(a)) indicate microvascular impair-ments5 and chronic vasodilation8in ICAS at baseline.After endovascular treatment, hemodynamics recoveredby reduced lateralization of 80% (p<0.04, Figure 1(a)) inline with known short-term effects.9,10However, visualattention deficits persisted (Figure 1(b)).10Here, improvedCTH11might counteract with cognitive decline by microemboli,12as postoperative WML increased slightly butnon-significantly (Figure 1(c)). In conclusion, hemodynam-ics recovered after asymptomatic ICAS revascularization,whereas cognitive impairments seem irreversible

Introduction:

When administering radiopharmaceuticals, the kidney is one of the dose-limiting organs [1]. Micro-physiological systems (MPS) for the in vitro evaluation of new potential radiopharmaceutical candidates should therefore be equipped with a functional kidney equivalent [2]. Hence the proximal tubule is responsible for most toxic interactions we generated a model of this part using a co-culture of human renal proximal tubule epithelial cells (RPTEC) and human umbilical vein endothelial cells (HUVEC) [3]. The functionality of the renal barrier was characterized by measuring transepithelial/transendothelial electrical resistance (TEER) and permeation of [18F]fluorodeoxyglucose (FDG).
Methods:
Investigations were performed in 24-well plates equipped with transwell inserts with a permeable membrane (pore size 0.4 µm). Viability and density of the cellular bilayer were measured using calcein staining. Apical and basolateral sites of the membrane were populated with RPTEC and HUVEC, respectively (each site 8x104 cells). Ionic conductance in the cell layers was measured using TEER. Basolateral-apical passage of [18F]FDG (produced in-house; 4 MBq/mL, equivalent to about 5 nmol/mL) through the cellular bilayer was measured using a gamma counter and expressed as percent passage.
Results:
In the proximal renal tubule model, calcein staining showed that the cellular bilayer reached confluence after 3 to 4 days. At this time point, the barrier showed a higher electrical resistance of 533 ± 47 Ω*cm2 across the cellular bilayer compared to 306 ± 26 Ω*cm2 across transwell blanks. Consistent with these results, [18F]FDG showed only 4 ± 1 % basolateral-apical passage through the intact cellular bilayer compared to 13.5 ± 1.5 % across transwell blanks. Morphological, electrical, and functional readouts therefore confirmed the integrity of the renal barrier in this model.
Conclusions:
This study demonstrates that measurement of [18F]FDG passage provides a functional test of the renal barrier in a proximal renal tubule model of the kidney. While the TEER value reflects the ionic conductance of the paracellular pathway in the epithelial layer, the flux of nonelectrolyte tracers such as [18F]FDG indicates the paracellular water flux as well as the pore size of the tight junctions [4]. In the next steps, apical-basolateral [18F]FDG transport will be investigated to functionally characterize reabsorption via sodium/glucose cotransporter 2 (SGLT2), which is mainly found in the proximal part of the renal tubule [5]. After characterization of the proximal renal tubule model in the static system, this kidney equivalent will be integrated into the fluidics system of a multicompartment MPS chip that also contains a liver equivalent and a tumor spheroid for use in radiopharmacological assays. With kidney and liver organoids first evidence for uptake, metabolism and excretion of a radioligand will be investigated.
 
Acknowledgements:
The authors like to express great appreciation for the financial support from the German Federal Ministry of Education and Research (BMBF) (Funding number 161L0275A/B).
References:
[1] Klaus et al., Radiat Oncol 2021, 16, 43. [2] Sihver et al., Curr Dir Biomed Eng 2022, 8, 532. [3] Schmieder et al., Curr Dir Biomed Eng 2019, 5, 1. [4] Srinivasan et al., J Lab Autom 2015, 20, 107. [5] Weber et al., Kidney Int 2016, 90, 627.

Introduction:

Due to the upregulation of somatostatin receptor subtype-2 (SSTR2) in neuroendocrine tumors, radiolabeled somatostatin analogs have been successfully used so far for diagnostic investigations and peptide receptor radionuclide therapy [1]. In the present work, both the somatostatin agonist (Tyr3)octreotate (TATE) and the somatostatin antagonist JR11 were conjugated with a cyclohexanediaminetriazole (CHDT) chelator for the potential labeling with Al18F, 68Ga or 111In. The radiopharmacological behavior of Al18F and 68Ga labeled CHDT-TATE and CHDT-JR11 were studied in BON-SSTR2 cells [2] in both monolayer (ML) and spheroid (SP) culture. The binding data were determined in static cell culture to have a basis for further assays using a microphysiological system (MPS) with dynamic properties [3].
Methods:
Spheroids of BON-SSTR2 cells were created according to a protocol by the vendor (Greiner Bio-One GmbH, Germany). Freshly harvested cells were incubated with magnetic nanoparticles in RPMI medium overnight. After loading, the cells were distributed in a 24-well-plate (3 x 10-4 cells/well) and placed on a plate with corresponding 24-point magnets in order to form SPs in the incubator for up to 5 days [4].
18F-labeling was performed with Al[18F]F2+ (TR-FLEX Cyclotron, Canada) and 68Ga-labeling with [68Ga]GaCl3 (68Ge/68Ga generator, iThemba Labs, South Africa) under mild conditions (20 min at 40°C). After incubation with the radiolabeled ligands the cells were washed; for internalization purpose the cells were treated with acidic glycine buffer (pH 3.0) to remove the bound molecules from the outer cellular membrane [5]. These samples correspond to the ligand-bound fraction and are measured in a gamma counter alongside the samples with the internalized ligand molecules.
Results:
Saturation binding analysis of Al18F-labeled CHDT-TATE and CHDT-JR11 revealed very good binding affinities with similar Kd-values toward ML (Al[18F]F-CHDT-TATE 12.4 ± 2.1 nM, Al[18F]F-CHDT-JR11 11.4 ± 0.3 nM) and for SPs (Al[18F]-CHDT-TATE 30 ± 6.6 nM, Al18F-CHDT-JR11 56 ± 20 nM). In contrast, [68Ga]Ga-CHDT-TATE had better binding affinities toward ML and SPs compared to [68Ga]Ga-CHDT-JR11 ([68Ga]Ga-CHDT-TATE ML 4.3 ± 0.5 nM, SPs 19 ± 2.2 nM; [68Ga]Ga-CHDT-JR11 ML 25.3 ± 13.9 nM, SPs 118 ± 38 nM). The maximal binding capacity (Bmax) was about 25-times higher for radiolabeled CHDT-JR11 (average 5.8 ± 0.3 pmol/mg) than for CHDT-TATE (average 0.23 ± 0.08 pmol/mg) both for ML and SPs.
The internalization assays showed that radiolabeled CHDT-TATE internalized about 4-times stronger than radiolabeled CHDT-JR11 based on percent of administered dose per µg of protein both for ML and for SPs (radiolabeled CHDT-TATE 0.22 ± 0.03 %AD/µg protein, radiolabeled CHDT-JR11 0.06 ± 0.02 %AD/µg protein).
Conclusions:
Both the agonist conjugate CHDT-TATE and the antagonist conjugate CHDT-JR11 were successfully labeled with Al18F and with 68Ga and assayed with SSTR2-expressing BON-SSTR2 cells in monolayer and spheroid form. The 25-times higher Bmax values of the radiolabeled antagonist appear advantageously regarding a potential theranostic application. Despite the fact that the SSTR2 antagonist only weakly internalizes in the cells the antagonists show effective treatment in clinical studies [6]. The next step is to compare the results with assays in dynamic MPS chips.
Acknowledgements:
The authors like to express great appreciation for the financial support from the LifeScience-Stiftung (Funding code: HZDR 2021.01).
The SSTR2 expressing BON-SSTR2 cells were kindly given by Dr. Grötzinger, University Hospital Charité Berlin.
References:
[1] Eychenne et al., Molecules 2020, 25, 4012. [2] Exner et al., Front Endocrinol 2018, 9, 146. [3] Busek et al., J Sens Sens Syst 2016, 5, 228. [4] Noel et al., J Vis Exp 2017, 126, e56081. [5] Matzku et al., Cancer Res 1986, 46, 3848. [6] Borgna et al., Eur J Nucl Med Mol Imaging 2022, 49, 1113.

Choosing the best memory layout for each hardware architecture is
increasingly important as more and more programs become memory
bound. Memory related optimizations typically depend on full control
over data layout. Thus, for portable codes that run across
heterogeneous hardware architectures, such a data layout is ideally
decoupled from the rest of a program.

The low-level abstraction of memory access (LLAMA) is a C++ library
that provides a zero-runtime-overhead abstraction layer, underneath
which memory layouts can be freely exchanged, focusing on
multidimensional arrays of nested, structured data. It provides a
framework for defining and switching custom memory mappings at compile
time to define data layouts, data access and access instrumentation,
making LLAMA an ideal tool to tackle memory-related optimization
challenges in heterogeneous computing.

The lecture sessions contain the following topics

Core Modern C++ (Move semantics, copy elision, advanced STL, ...)
Expert C++ (variadic templates, perfect forwarding, concepts, ...)
Tools (valgrind, static code analysis, profiling, ...)
Concurrency (threads, mutexes, atomic types, ...)
... more C++'20 features (modules, ranges, ...)

Welcome to the fourth iteration of a C++ course for the high energy physics community organised in collaboration between the Software Institute for Data Intensive Sciences and the Training Working Group of the HEP Software Foundation.

In this talk, I presented the main findings from the project RAMSES-4-CE regarding polymer characterisation using different sensors. This activity was part of the HZDR innovation tour 2022.

Surface High harmonic generation (SHHG) arising from the interaction of high and ultra-
high intensity lasers with solid density targets has been extensively studied during recent
years. Besides being a promising source for applications on ultrafast science, the
sensitivity of SHHG mechanisms with respect to changes of pump laser parameters or
target pre-plasma conditions makes the harmonic spectrum a useful diagnostic to gain
insight into the interaction between the laser and the target front surface where, in case of
a solid density target, most of the energy absorption between laser and target takes place.
In the present work, the first measurements of high harmonic spectra on the Draco PW
laser system at HZDR are presented. Most measurements were done using a single
plasma mirror system, achieving a contrast of 10-7 at -1ps for a 5.4x1021W/cm2, 30fs
800nm pulse. XUV spectra were measured for a wide range of different target materials
(plastic, metal, glass), thicknesses; from bulk SiO2 substrates to few tens of nm foils where
relativistic transparency starts to occur; as well as different laser energies (a0~7-50). The
spectral range of the spectrometer (53nm to ~17nm, 15th to 47th harmonic, limited by the
filtering) allowed us to measure changes in SHHG along the spectrum for different
interaction conditions. These measurements were carried in parallel with proton
acceleration experiments, aiming at using the harmonic generation as a gauge for the
laser-plasma interaction at different interaction regimes, and to our knowledge constitute
one of the first measurements of relativistic surface harmonics with a PW short pulse laser.

Efficient personnel scheduling plays a significant role in matching workload demand in organizations. However, staff scheduling is sometimes affected by unexpected events, such as the COVID-19 pandemic, that disrupt regular operations. Since infectious diseases like COVID-19 transmit mainly through close contact with individuals, an efficient way to prevent the spread is by limiting the number of on-site employees in the workplace along with regular testing. Thus, determining an optimal scheduling and testing strategy that meets the organization's goals and prevents the spread of the virus is crucial during disease outbreaks.
In this paper, we formulate these challenges in the framework of two Mixed Integer Non-linear Programming (MINLP) models. The first model aims to derive optimal staff occupancy and testing strategies to minimize the risk of infection among employees, while the second model aims at only optimal staff occupancy under a random testing strategy. To solve the problems expressed in the models, we propose a canonical genetic algorithm as well as two commercial solvers. Using both real and synthetic contact networks of employees, our results show that following the recommended occupancy and testing strategy reduces the risk of infection 25\%--60\% under different scenarios.

Interaction of ultrafast relativistic intensity laser pulses with matter has shown to be a promising field for the study of matter at extreme conditions, electromagnetic fields generation/amplification, high energy radiation emission and particle acceleration. For most of the aforementioned applications, advanced proposed schemes require stringent tailoring and monitoring of the target/plasma parameters during the interaction. The short (fs) temporal and small (sub-micron) spatial scales of the evolution of these parameters make direct measurements a challening task, even more considering that these plasmas are usually overdense for conventional optical diagnostics.

Currently, a pump-probe set up is being developed at HZDR to gain insight into the internal evolution of overdense laser driven plasmas. The XUV beam generated by one of the arms of the Draco laser, through Relativistic Oscillating Mirror High Harmonic Generation, will be used to probe a plasma driven by a second arm of the laser system. The initial set up for these experiments will be shown and probing options of the platform will be discussed.

Introduction:

Radiolabeled prostate-specific membrane antigen (PSMA) ligands have been successfully developed in recent years for diagnosis and therapy of prostate cancer [1]. A potential new PSMA radioligand would, after in vitro characterization, normally be further evaluated in small animals. However, the use of micro-physiological systems (MPS), an organ-on-chip technology in which human cell spheroids and organoids are treated in a circuit under defined conditions [2,3], should lead to a reduction of animal experiments.
In the present study, experiments with the novel 64Cu-labeled PSMA antagonist FR52 were performed using 2D or 3D cultures of LNCaP cells in MPS chips. Our aim was to determine binding parameters (Kd, Bmax) in the MPS chip and to compare them with the results of assays in well plates (WP).
Methods:
Derived from the compound PSMA-617 [4], instead of DOTA a cyclohexanediamine-triazole (CHDT) chelator was conjugated, resulting in the conjugate FR52 (in-house synthesis). FR52 was radiolabeled with 64Cu (molar activity: 14.2 ± 2.2 MBq/nmol).
For the assays, 5 x 104 LNCaP cells were placed in 3 wells of an MPS module (à 0.2 cm2), either as monolayer or as spheroids and cultured for 2 to 7 days. The MPS chips include an integrated micropump, driven by a controller, that generates a pulsatile flow of media that runs through the capillaries and keeps the cells alive [5] (Fig. 1).
After blocking of adjacent cell samples (PSMA pharmacophore 0.8 mM; 30 min) [64Cu]Cu-FR52 (6 to 200 nM) was added to all samples and pumped through the MPS for 10 min (volume: 0.1 mL/well; 80 bpm; volume flow 6.4 µL/s). After PBS washing and exposing the MPS chips to an imaging plate, the cells were lysed and in vials measured in a gamma counter. Evaluation was processed with the analysis program GraphPad Prism.
Results:
Saturation assays with [64Cu]Cu-FR52 in MPS revealed similar high binding affinities (Kd) for LNCaP monolayer and spheroids (MPS-monolayer Kd: 33 ± 6 nM; MPS-spheroids Kd: 36 ± 8 nM). Also the binding capacities (Bmax) were in the same range (MPS-monolayer Bmax: 0.57 ± 0.04 pmol/mg; MPS-spheroids Bmax: 0.35 ± 0.03 pmol/mg). The binding affinity to LNCaP spheroids in WP was similar to that in MPS, but the binding capacity was slightly lower than in the chip experiments (WP-spheroids Kd: 59 ± 6 nM; WP-spheroids Bmax: 0.22 ± 0.01 pmol/mg). LNCaP monolayer treatment in WP was performed in previous experiments with 18F, 68Ga or 111In labeled FR52. Those Kd values were slightly lower (WP-monolayer Kd: 18 ± 2 nM) and the Bmax values were slightly higher (WP-monolayer Bmax: 0.7 to 3.5 pmol/mg).
Conclusions:
The successful evaluation of the binding parameters of the 64Cu-labeled PSMA antagonist FR52 using MPS is a promising step to foster the reduction of animal experiments in preclinical evaluation. Moreover [64Cu]Cu-FR52 seems to be a promising candidate. Nevertheless, further experiments with kidney and liver organoids in MPS should investigate first evidence for uptake, metabolism and excretion of [64Cu]Cu-FR52.
Acknowledgements:
The authors like to express great appreciation for the financial support from the German Federal Ministry of Education and Research (BMBF) (Funding number 161L0275A/B).
References:
[1] Neels et al., Cancers 2021, 13, 6255 [2] Busek et al., J Sens Sens Syst 2016, 5, 228. [3] Schmieder et al., Proc SPIE 2020, 11268, 1126804_1. [4] Benešová et al., J Nucl Med 2015, 56, 914. [5] Sihver et al., Curr Dir Biomed Eng 2022, 8, 532.

Aim/Introduction: A recently developed cyclohexanediaminetriazole- chelator enabling 18F-labelling using the Al[18F]F approach was conjugated via copper-catalysed azide-alkyne cycloaddition to the PSMA-binding motif glutamate-urea-lysine connected with 1-naphthyl-D-alanine[1] (ligand L). In the present study radiolabelled L will be characterized on PSMA-positive prostate cancerspheroids. Three-dimensional cell models offer structure and functional properties closer to in vivo conditions than two-dimensional cell culture models. Spheroids show altered cell-cell and cell-extracellular matrix interactions and are useful for better understanding the nature of tumours concerning drug uptake, toxicity, hypoxia, tissue growth and therapeutic effects. The aim of this study was to investigate the radiopharmacological potential of 18F- and 68Ga-labelled L using LNCaP-spheroids regarding binding properties and internalisation behaviour. The results will be compared with data obtained from LNCaP-monolayer cell culture.
Materials and Methods: Spheroids of LNCaP and PC3 (PSMA-negative) cells were created according to a protocol by the vendor. Freshly harvested cells were incubated with magnetic nanoparticles overnight. After loading, the cells were distributed in a 24-well-plate (10-4 cells/well), covered with a lid equipped with 24 small magnet devices for 5 days and kept in an incubator so that the cells could form spheroids [2]. After incubation with radiolabelled ligand (RCY >95%) the spheroids were washed, exposed to a phosphor imaging plate and the data analysed. Internalisation experiments were carried out by the “acid wash” method.
Results: The method of creating spheroids by magnetised prostate cancer cell lines and treating them with a magnet device was applied successfully and resulted in spheroids with a diameter size of about 500 μm. The evaluation of first saturation experiments with LNCaP spheroids provided preliminary affinity data with Kd values in the range of 30 to 40 nM. These results are comparable to that of monolayer cell homogenate. Internalisation experiments with LNCaP-spheroids are ongoing.
Conclusion: The novel radiolabelled PSMA-ligand L can be radiopharmacologically characterised on prostate cancer cell homogenate but also spheroids. The establishing of three-dimensional cell aggregates by magnetised cells and, moreover, the investigation of new radiolabelled conjugates for potential PET/SPECT application or even therapeutic treatment of cancer entities using spheroids is a valuable and promising method. Next, it is planned to use the LNCaP-spheroids for evaluation of PSMA-radioligands in a proof-of-conceptstudy applying the technology of Micro-Physiological Systems (multiorgan-chips) [3].
References: [1] Sihver, Eur. J. Nucl. Med. Mol. Imaging 2019, 26 (Suppl 1), S132. [2] Turker, ACS Biomater. Sci. Eng. 2018, 4, 787. [3] Maschmeyer, Lab Chip 2015, 15, 2688.

Chemoenzymatic cascades are an important tool for advanced synthesis in chemistry. However, these cascades are often limited due to the incompatibility issue between two distinct catalysts and reactions. To address this issue, we present a simple multistep one-pot platform, in which nanoparticle catalysts are prepared to allow chemo- and biocatalytic reactions performed sequentially in water and Pickering emulsions. The preparation of particle catalysts is accomplished in just two steps by polymer modifications and [RuCl₂(pcymene)]₂ coordination, while the benefits of using them for chemoenzymatic synthesis are multifaceted. They act not only as asymmetric catalysts for asymmetric transfer hydrogenation from acetophenone to 1-phenylethanol in water with up to 99 % conversion and 93 % ee, but also as an emulsifier to form stable Pickering emulsions. By the addition of Candida antarctica lipase B into the emulsions, the second-step reaction of enantioselective acylation was achieved with 38 % conversion and 99 % ee. Therefore, we successfully present a simple method to enable chemoenzymatic cascades by combining particle catalysts and enzymes in water and Pickering emulsions in a sequential fashion, which can be generalized for other cascade syntheses with different chemo- and biocatalysts in the future.

Actinide und Lanthanide spielen eine wichtige Rolle bei vielen industriellen Anwendungen und können durch den Abbau, die Nutzung und Entsorgung in die Umwelt gelangen. Genaue Kenntnisse über das komplexe Verhalten und die Wechselwirkung dieser Metalle mit der Biosphäre, z. B. mit Bakterien, Pilzen und Pflanzen sind notwendig, um ein mögliches Gefährdungspotential für den Menschen abschätzen und entsprechende Schutzmaßnahmen ergreifen zu können. Darüber hinaus ermöglicht dieses Wissen die Entwicklung biologischer Verfahren zur Entfernung radioaktiver und toxischer Metalle und Schadstoffe aus Abwässern und kontaminierten Böden. Nach den Unfällen in Tschernobyl und Fukushima ist deutlich geworden, dass insbesondere Pilze große Mengen an Radionukliden und Schwermetallen aufnehmen und anreichern können, allerdings sind die zugrundeliegenden Prozesse noch nicht gut verstanden.
Ziel dieser Studie war es die Wechselwirkungen von Myzel ausgewählter holz- und bodenbewohnender Pilze mit Uran und Europium als Analogon für die dreiwertigen Actinide Americium und Curium zu untersuchen. Neben der Bestimmung der Metall-komplexe in den Sorptionslösungen wurden die gebildeten Metall-Pilzspezies mittels Rastertransmissionselektronenmikroskopie gekoppelt mit energiedispersiver Röntgen-mikroanalyse, zeitaufgelöster laser-induzierter Fluoreszenzspektroskopie und chemischer Mikroskopie charakterisiert. Schizophyllum commune zeigte signifikant höhere Metall-Bindungskapazitäten im Vergleich zu den anderen holzbewohnenden Pilzen Pleurotus ostreatus und Lentinus tigrinus sowie zu dem bodenbewohnenden Pilz Leucoagaricus naucinus. Die Metalle werden insbesondere an der Zelloberfläche, in den Zellmembranen und Membranen verschiedener Organellen, aber teilweise auch im Zytoplasma gebunden. Die spektroskopischen Untersuchungen des metallbelasteten Pilzmyzels haben gezeigt, dass Phosphatgruppen verschiedener Biomoleküle neben den Carboxylgruppen eine große Rolle bei der Immobilisierung des Urans und des Europiums durch Pilze spielen.

Objective: The somatostatin receptor subtype 2 (SSTR2) is a suitable target for the diagnosis and therapy of neuroendocrine tumors using radiolabeled ligands [1]. BON-1S cells have been described to express SSTR2 receptors in vitro [2]. We therefore established 2D and 3D cell culture systems of BON-1S cells. For SSTR2 ligand binding, BON-1S cells cultured as monolayer or spheroids were incubated with an SSTR2 agonist (NODAGA-TATE) or an SSTR2 antagonist (NODAGA-JR11). Both were labeled with either 68Ga- or 64Cu and their respective binding and uptake were determined. Understanding the binding data is a prerequisite for using spheroids of BON-1S cells in a
Micro Physiological System (MPS) [3].
Methods: Spheroids of SSTR2 containing BON-1S cells were created as follows: Freshly harvested cells were incubated with magnetic nanoparticles in RPMI medium overnight. After magnetic particle uptake, cells were split into a 24-well-plate (1.5 x 10-4 cells/well). In an incubator, the magnetic particles were moved via a magnetic drive for five days, to allow the formation of spheroids [4]. After incubation with the 68Ga- or 64Cu-labeled radioligands (RCY>95%), the BON-1S cells, either as monolayer or as spheroids, were washed and treated with acidic glycine buffer (pH 3.0) to remove the bound but not yet internalized molecules from the outer cellular membrane.
After this washing step, the remaining radioligand molecules are assumed to represent internalized molecules [5]. In the monolayer,
internalization was determined after 10 minutes, 1 hour and 3 hours after addition of the radioligand to the respective culture.
Results: Saturation analysis of radiolabeled NODAGA-TATE as well as NODAGA-JR11 on BON-S1 monolayer yielded similar Kd values in the low nanomolar range (2.3 to 8.6 nM). Affinity of the respective radiolabeled ligand was much lower on BON-1S spheroids, with Kd values around 30 nM for both 64Cu-labeled ligands and almost 60 nM for the 68Ga-labeled ligands. The maximal binding capacity (Bmax) was higher on monolayers and spheroids for radiolabeled JR11 (NODAGA-TATE: monolayer 0.3 pmol/mg, spheroids 0.8 pmol/mg; NODAGA-JR11: monolayer and spheroids 1.2 pmol/mg). The internalization assay showed a ratio of internalized to surface bound radiolabeled NODAGA-TATE of about 80% to 20% for both forms of cell culture, for radiolabeled JR11 a ratio of 8% to 92% was determined, each after a 60 min-incubation time. The internalization after the three time points was ca. 10 times lower in case of radiolabeled JR11 (0.25% (TATE) versus maximal 0.03% (JR11) of administered activity amount/µg protein).
Conclusions: Using monolayer or spheroids of BON-1S cells (the latter were generated by the iron nanoparticle method) we could
estimate reliable and reproducible binding parameters for a radiolabeled agonist and antagonist of SSTR2. There are obvious differences in binding affinities of the examined radiolabeled conjugates in monolayer cell culture compared to the spheroids.
Acknowledgements: The SSTR2 expressing BON-1S cells were kindly given by Prof. Dr. Wiedenmann, University Hospital Charité
Berlin.
References:
[1] Eychenne, Molecules 2020, 25, 4012.
[2] Exner, Front Endocrinol 2018, 9, 146.
[3] Busek, J Sens Sens Syst 2016, 5, 228.
[4] Noel, J Vis Exp 2017, 126, e56081.
[5] Matzku, Cancer Res 1986, 46, 3848.

Electronic waste (e-waste) is a fast-growing and complex material stream, and its adequate management requires robust identification tools. Plastics are major components of e-waste (~25% of its total) and polymer compositions vary depending on its initial function in the electronic device, including the presence of additives to compensate for function loss and polymer blends (e.g ABS/PS). Recycling of these increasingly complex e-waste polymers calls for innovative, fast, and spatially-resolved identification tools compatible with conveyor belt operations.
We propose fast identification of polymers in e-waste using hyperspectral imagery (HSI) and Raman spectroscopy. We evaluated the potential of such methods for resolving diagnostic spectral features (fingerprints) in 23 polymer types, including black plastics, and determined the minimum acquisition requirements for robust identification of polymers considering the recycling industry demands. We employed short-wave infrared (SWIR-HSI, SPECIM AisaFENIX
We identified fingerprints for each material based on previous literature reports: a positive identification was assigned for fingerprints with signal-to-noise-ratios > 4 (hull-corrected reflectance - HSI) or > 3 (Raman). We identified 60% of the transparent and light-colored plastic types using SWIR-HSI, and two out of five black plastic types using MWIR-HSI information. In total, HSI-reflectance methods were suitable for characterization of 16 plastic types (70%), acquiring simultaneous spectral and spatial information at fast rates. Still, the need for characterizing black plastics was not fully met using HSI-reflectance sensors.
We propose to employ point Raman spectroscopy as the ultimate tool for polymer identification and evaluated its potential for integration with HSI data. We performed short-time point Raman measurements (≤ 2 seconds), investigating if the method is compatible with the fast-paced data acquisition rates required by the recycling industry. We identified fingerprints for all polymers using signals from short-time point Raman measurements (transparent plastics: 0.5 seconds, black plastics: 1 second).
We elaborated sensor-specific libraries for each plastic type for future cross-validation and correlation in automated polymer detection during recycling operations (dictionary learning). This reference data represents maps which capture the spectral variability within the reference materials as a training dataset. To evaluate the added value of the spatial variability recorded by HSI sensors, we showcase the application of our spectral library for polymer identification and mapping in artificially mixed samples of plastic debris.
Our RAMSES network, a project financed by the EU via the KIC Raw Materials, develops the tools for combining different sensor types: HSI-reflectance sensors and RGB cameras at the beginning of the line record information needed to determine representative spectral domains. This signal is then used, along with the polymer’s spectral library, to identify transparent and light-colored plastics. The spatial and spectral domain information are used to direct Raman point acquisitions for identification of black plastics and polymer blends. This intertwined multi- sensor network relies on fast data acquisition and processing supported by spectral libraries and machine learning algorithms targeting object detection and spectral data fusion. This investigation contributes to enabling highly accurate identification of polymers, specifying the conditions for rapid smart multi-sensor data acquisition and processing.

Advanced energy materials and effective manufacturing facilities of battery cells production are key parameters to overcome the economic barrier to entry into the market. This poster shows an annealing technology using the millisecond range flash lamp annealing (FLA), which takes place without preheating and can be both a vacuum and vacuum-free method. This procedure at a pilot stage is characterized by significant savings in time, energy, resource and production costs enabling to enhance the sustainability of the battery production generally. It will review, as example, the advances that are obtained using FLA on new materials for high energy density thin film electrodes based on silicon. These new materials have the capability of realizing an excellent performance of the energy storage system, e.g. of lithium ion batteries and beyond, for vehicles and stationary applications. It will be demonstrated how it is possible to develop a silicon metal electrode (SiMe) with outstanding properties with a higher capacity than the standard of the day, compatible to many variants of lithium cells, solvents free, cost-effective and capable to be integrated on roll-to- roll processing.

Superconductivity in group IV semiconductors is desired for hybrid devices combining both semiconducting and superconducting properties. Following boron-doped diamond and Si, superconductivity has been observed in gallium-doped Ge; however, the obtained specimen is in polycrystalline form [Phys. Rev. Lett. 102, 217003 (2009)]. Here we present superconducting single-crystalline Ge hyperdoped with gallium or aluminum by ion implantation and rear-side flash lamp annealing. The maximum concentration of Al and Ga incorporated into substitutional positions in Ge is 8 times higher than the equilibrium solid solubility. This corresponds to a hole concentration above 1021cm-3. Using density functional theory in the local-density approximation and pseudopotential plane-wave approach, we show that the superconductivity in p-type Ge is phonon mediated. According to the ab initio calculations, the critical superconducting temperature for Al- and Ga-doped Ge is in the range of 0.45 K for 6.25at.% of dopant concentration, being in qualitative agreement with experimentally obtained values. Being Si-chip technology compatible, superconducting Ge can find wide applications in quantum technology.

Perovskite oxides exhibit rich physics related to ionic defects. In particular, the defect concentration and distribution alter the lattice parameters and affect the competitive interplay between strongly correlated electrons, enabling numerous applications as sensors, catalysts, and memristive devices. In this work, helium-ion irradiation is demonstrated as an effective, low-temperature tool to modulate the vacancy profiles in epitaxial La0.6Sr0.4CoO3-δ thin films. A significant lattice expansion solely along the out-of-plane direction is observed. By proper tuning of the irradiation parameters, the resistivity is increased up to several orders of magnitude. These results offer a new playground for optimizing oxide-based spintronic and electronic devices.

In the context of the nuclear fuel cycle, U1-yPuyO2-x Mixed Oxides (MOx) are currently the most employed fuels. These materials have to meet accurate physico-chemical properties, known to change drastically during irradiation with the formation of Fission Products (FP). Investigating the FP behaviour is thus crucial to predict the fuel properties evolution during irradiation. Model Uranium-based materials called SIMfuel have been developed in the last decades to overcome the high radiotoxicity of UO2 spent fuel, and to enable separation-of-effect studies on its otherwise overwhelmingly complicated chemistry.In this work, a fabrication route for U1-yPuyO2-x SIMfuel (SIMMOx) has been developed, in order to study the speciation of soluble FP (Ce, La, Nd, Sr, Y, Zr) inside spent MOx fuel, and their interaction with the U1-yPuyO2-x matrix. The resulting material is representative of irradiated MOx fuel with Pu content of 24 mass% (PU/(U+Pu) : 26%)and a burnup of 13 at.%. XRD and EPMA show a material representative of real spent fuel (U,Pu)O2 matrix: globally monophasic, and compliant with the homogeneity requirement of irradiated MOx. Raman microscopy confirmed the samples homogeneity, showing that all the FP successfully entered the solid solution. Pu-enriched zones (<30 μm) contain higher FP concentration, showing that this phenomenon, already observed in irradiated fuel, is due also to thermodynamics and not only to burnup, as previously assumed. XAS analysis supplied crucial information such as the oxidation states, the O/M ratio, and the prevalent chemical form of each actinide, and FP. A charge compensation mechanism between the (U,Pu)O2 matrix and the FP in solution has been observed.

Introduction
Adjuvant radio(chemo)therapy (RT) is a common treatment of primary brain tumor patients. Irradiation with protons reduced radiation exposure to the tumor-surrounding tissue. As the normal tissue is still unavoidably exposed to a certain amount of radiation, the aim of this study was to determine the radiation effect on normal appearing white matter (WM) of glioma patients treated with proton RT based on the changes of the relative cerebral blood volume (rCBV).

Methods
MRI data of 14 glioma patients (grade II-IV) undergoing gross tumor resection followed by proton RT were acquired prior to RT and 3, 6 and 9 months after RT and included T1-weighted images and dynamic susceptibility contrast (DSC) imaging.
Planning CTs, dose maps and CTV contours were registered to the T1w-images using ANTs1 and WM segmentation was done on T1w-images using SPM122. Normal-appearing tissue was censored by excluding the CTV and voxels appearing abnormal on FLAIR imaging.
CBV-maps were calculated voxel wisely as the area under curve determined by integrating the y-variate fit to the time curves of the 4D DSC image. Relative CBV (rCBV) maps were normalized to a reference region of white matter receiving less than 1Gy. Time-dependent alterations ΔrCBV were determined by the percentage difference between follow-up and baseline measurement for the whole brain WM as well as for dose-separated bins of low (1-20Gy), medium (20-40Gy) and high dose regions (>40Gy).

Results and conclusion
The evaluation of whole brain WM as well as of dose-separated regions showed no significant alterations between baseline and follow-up rCBV. A trend toward decreasing perfusion appeared after 9 months after RT in the high-dose range. Previous studies measured a radiation-induced decrease in WM blood volume prominently appearing in the high-dose range3,4,5. A study showing early radiation response of decreasing rCBV followed by a recovery 3 months after RT agrees with our observation of constant rCBV 3-9 months after radiation6. In future studies our focus will be on the evaluation of brain subregions as well as the analysis of GM radiation response.

Purpose: Adjuvant radio(chemo)therapy (RT) is part of the standard treatment of gliomas. Safety margins ensuring the coverage of microscopic tumour expansion of diffusely infiltrating gliomas and compensating for systematic positioning errors inevitably result in the normal-appearing (NA) brain tissue surrounding the tumour to be affected by radiation. The aim of the study was to investigate dose- and time-dependent diffusion alterations of NA white matter (WM) structures following RT using tract-based spatial statistics (TBSS).

Methods: As part of a prospective, longitudinal study, magnetic resonance imaging (MRI) data of 24 grade II-IV glioma patients treated with photons, protons or mixed-modality therapy were acquired. MRIs before RT and 3-monthly during follow-up obtained up to three years after RT included diffusion tensor images (DTI) (TR/TE=6500/66ms, 2×2×2mm³, 32 directions, b=1000mm/s²). Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were calculated from the DTI data. Corresponding radiation dose maps and clinical target volume (CTV) contours were aligned to MRI using ANTs. NA tissue was defined as brain tissue, excluding the CTV and areas of T2-hyperintensities. All FA images were nonlinearly registered to the “FMRI58B-FA atlas” from FSL with ANTs before applying parts of the TBSS algorithm to create a FA skeleton (Figure 1).
The FA skeleton was combined with the “JHU-ICBM-labels-1mm atlas” to measure the diffusion in 19 WM structures. Relative signal changes of each WM structure were calculated as the difference between follow-up and the corresponding baseline signal and evaluated using a paired t-test. A multivariate linear mixed effects model was applied to determine diffusion changes as function of time after RT and mean dose delivered to the corresponding structure. Data from paired structures of the right and left hemispheres were combined for the analysis. Structures containing less than 50 voxels were excluded.

Results: Figure 2 shows nine structures exhibiting significant DTI signal changes after RT. Posterior thalamic radiation showed the greatest alterations of the DTI parameters and a significant dose- and time-dependency of MD (-0.111%/month, -0.135%/Gy), RD (-0.14%/month, -0.171%/Gy) and AD (-0.09%/month, -0.1%/Gy). The strongest correlation of FA with time appeared in superior longitudinal fasciculus (0.045%/month) and with dose in internal capsula (0.056%/Gy). All significant changes represented decreasing MD, RD, and AD and increasing FA after irradiation. No significant correlations were detected in medial lemniscus.

Conclusion: Several WM structures showed significant time- and dose-dependent DTI signal changes after RT, which might indicate a stronger radiosensitivity of these structures. The results are in agreement with the investigation of the dose-dependent irradiation effects on WM diffusion already performed by Raschke et al. (Radiother Oncol. 2019;140:110–115) and Dünger et al. (Radiother Oncol. 2021;164:66–72).

Introduction:

Adjuvant radio(chemo)therapy (RT) is part of the treatment of primary brain tumor patients. In order to capture microscopic tumor extension and to compensate for random and systematic positioning uncertainties, it is inevitable that tumor-surrounding normal brain tissue is irradiated. The aim of this study was to determine relative cerebral blood volume (rCBV) changes in glioma patients before and after RT in normal appearing white matter (WM) and grey matter (GM).

Methods:

As part of an ongoing study, anatomical and functional MRI data of glioma patients undergoing gross tumor resection followed by RT is being collected. The analysis of a subset of this cohort, 17 glioma patients (3 grade II, 11 grade III, 3 grade IV, average age 46.9y ± 13.2y) is presented here. Two patients were treated with photon therapy, 14 patients with proton therapy and one patient received treatment modalities. MRI scans acquired prior to RT and at least one follow-up MRI obtained 3, 6 and 9 months after RT was evaluated. All MRI data were collected on a 3T Philips Ingenuity PET/MR scanner (Philips, Eindhoven, The Netherlands) using an 8 channel head coil and included anatomical T1w-images (3D-GRE, TR/TE=10/3.7ms, FA=20°, voxel size 1×1×1mm3) and dynamic susceptibility contrast (DSC) imaging using a PRESTO sequence (TR/TE=15/21ms, 60 dynamics, dynamic scantime=1.7s, voxel size 3.6×3.6×3.5mm3) with intravenous gadolinium contrast agent (0.1mol/kg, 4ml/s, 7s delay) followed by a saline flush (20ml, 4ml/s). The CBV-map (fig. 1D) was calculated as the area under curve (AUC) of the voxelwise time course of the 4D PRESTO image.
Computed tomographies (CTs) used for planning, radiation dose (fig.1C) and clinical target volume (CTV) contours were registered to the T1w images using ANTs1 . T1w-images were segmented into GM and WM using SPM122 and the corresponding 95% tissue probability maps were rigidly registered with ANTs1 to the CBV-map. B1 inhomogeneities as well as voxels with strong signal loss due to susceptibility artefacts were excluded. Only voxels outside the CTV and without any abnormalities appearing on the FLAIR image were considered.
Symmetrical GM and WM ROIs in supraventricular contralateral and ipsilateral hemisphere (fig.1A,B) were evaluated. The relative CBV (rCBV) was calculated as the ratio of the mean ipsilateral and contralateral CBV:
rCBV=(CBV_ipsi)/(CBV_contra )
The radiation dose in the ROI was determined as the dose difference of ipsilateral to contralateral side.
In a second analysis, the ROI was divided into bins of relative dose differences (ΔRD): low (0-20Gy), medium (20-40Gy) and high (>40Gy). Time-dependent alteration of rCBV was determined by the normalized difference between follow-up (v0x) and baseline measurement:
ΔrCBV=(rCBV_v0x–rCBV_baseline)/(rCBV_baseline )
Dose- and time-dependent ΔrCBV distributions were compared with the paired Wilcoxon signed-rank test.

Results:

The entire ROIs (fig. 2G,H) as well as the dose-separated regions (fig. 2A-F) of GM and WM rCBV did not show significant changes between baseline and follow-up, neither over time nor with increasing dose. One exception was the statistically significantly reduced mean ΔrCBV of -7.6% (p<0.008) after 6 months in WM volumes receiving a ΔRD of 0-20Gy (fig. 2A). In volumes receiving a ΔRD of <40Gy a trend towards increasing rCBV was detected 9 months after RT [mean WM +22,4% (p=0.063) and mean GM +3.1% (p=0.098); fig. 2C and 2F]. Patient-dependent fluctuations were higher in WM-regions than in GM-regions, however, the deviations remained below 20%.

Discussion:

The evaluation of radiation-induced rCBV changes in normal-appearing tissue resulted mainly in constant perfusion without continuous changes after RT, while the majority of the previous studies reported a perfusion reduction prominently appearing in high radiation dose regions3–7. Significant rCBV reduction 6-9 months after RT with a recovery after 18 month in low-dose areas was reported in combined grey and white matter region7, which is in line with our results of WM perfusion decrease in low- ΔRD volumes. However, the authors7 also reported similar behavior for high-dose regions not consistent with our results. An early radiation response of decreasing rCBV followed by a recovery 3 months after RT has also been measured8, which agrees with our observation of constant rCBV 3, 6 and 9 months after radiation. One study reported increasing rCBV in the low-dose region9, while our results indicated a trend for increasing rCBV in the high ΔRD area. It is possible, that the trend to perfusion increase did not reach significance due to the low number of patients especially for the WM evaluation.

In this paper, we issue an error analysis for integration over discrete surfaces using the surface
parametrization presented in [PS22] as well as prove why even-degree polynomials exhibit a higher
convergence rate than odd-degree polynomials. Additionally, we provide some numerical examples
that illustrate our findings and propose a potential approach that overcomes the problems associated
with the original one.

We present a symmetry-preserving scheme to derive the pion and kaon generalized parton distributions (GPDs) in Euclidean space. The key to maintaining crucial symmetries under this approach is the treatment of the scattering amplitude, such that it contains both the traditional leading-order contributions and the scalar/vector pole contribution automatically, the latter being necessary to ensure the soft-pion theorem. The GPD is extracted analytically via the uniqueness and definition of the Mellin moments and we find that it naturally matches the double distribution; consequently, the polynomiality condition and sum rules are satisfied. The present scheme thus paves the way for the extraction of the GPD in Euclidean space using the Dyson-Schwinger equation framework or similar continuum approaches.

Ge nanocrystals embedded in amorphous TaZrO_x matrices were synthesized by a magnetron co-sputtering process in a size-controlled manner, separated from each other by a superlattice approach of alternating TaZrO_x-Ge/TaZrO_x layers. Ge offers, in contrast to silicon, a large Exciton-Bohr radius, which allows the regulation of the bandgap by the diameter.

After annealing at 725 °C, Ge nanostructures were found to phase-separate and crystallize [1]. The addition of Sn to Ge promises a way towards a direct bandgap Ge-based semiconductor material [2] in a wide concentration range between 6 at.-% and 22 at.-% of Sn [3]. A direct bandgap material, which is fully compatible to common Si-CMOS processes would enable the integration in future devices, like light emitters or detectors.

The fabrication of GeSn alloys is challenging, due to the low solubility of Sn in Ge [4] but it is known that Ge nanocrystals after annealing contain a higher concentration of foreign atoms than expected in thermodynamic equilibrium [1].

Different structural measurements like EDX or Raman scattering monitor the structural changes within the Ge nanostructures by addition of Sn to the superlattice structure under annealing temperatures between 600 °C and 800 °C. TEM EDX measurements revealed that the TaZrO_x, which acts as an efficient diffusion barrier for Ge, does not prohibit the diffusion of the Sn completely. However, the formation of pure Sn nanocrystals was not observed. In addition, crystallization of the matrix material can be avoided for appropriate annealing temperatures.

1. D. Lehninger, F. Honeit, D. Rafaja, V. Klemm, C. Röder, L. Khomenkova, F. Schneider, J. von Borany, and J. Heitmann, MRS Bull. 511–512, 654 (2022).
2. A. Slav, C. Palade, C. Logofatu, I. Dascalescu, A. M. Lepadatu, I. Stavarache, F. Comanescu, S. Iftimie, S. Antohe, S. Lazanu, V. S. Teodorescu, D. Buca, M. L. Ciurea, M. Braic, and T. Stoica, ACS Appl. Nano Mater. 2, 3626 (2019).
3. W.-J. Yin, X.-G. Gong, and S.-H. Wei, Phys. Rev. B 78, 161203(4) (2008).
4. H. Li, J. Brouillet, A. Salas, X. Wang, and J. Liu, Opt. Mater. Express 3, 1385 (2013).

We report on the realization of an extremely sensitive x-ray polarization microscope, allowing to detect tiniest polarization changes of 1 in 100 billion (10^−11) with a μm-size focused beam. The extreme degree of polarization purity places the most stringent requirements on the orientation of the polarizer and analyzer crystals as well as the composition and the form fidelity of the lenses, which must not exhibit any birefringence. The results show that these requirements are currently only met by polymer lenses. Highly sensitive scanning x-ray polarization microscopy thus is established as a new method. It can provide new insights in a wide range of applications ranging from quantum electrodynamics and quantum optics to x-ray spectroscopy, materials research, and laser physics.

Biocomposites of magnetite nanoparticles in combination with various metal-binding proteins are able to sorb preferentially gallium from less concentrated process wastewater from the semiconductor industry. Subsequent chemical and physical modifications lead to further stabilization of the composites and increase the binding performance. The different biocomposites were compared and evaluated in terms of their binding performance and reusability. Kombucha was used as a sustainable desorbent to replace EDTA.

Fluctuation electron microscopy (FEM) analyzes intensity fluctuations within diffraction patterns in order to draw conclusions regarding the structure of amorphous materials by calculating the normalized variance V(k, R). Ideally, such experiments only evaluate elastically diffracted electrons.However, an undesired inelastic background intensity is always present and degrades the FEM data. Energy filtered FEM experiments were performed on amorphous germanium created by self-ion implantation. FEM data were acquired in a transmission electron microscope at 60 and 300 kV with different electron doses as well as varying energy filter slit widths at two sample thicknesses. Generally, the measurements reveal that energy filtering greatly improves FEM data at both beam energies and sample thicknesses by removing a certain amount of the inelastic background intensity in the diffraction patterns. The narrower the energy filter, the larger the normalized variance. This brings energy filtered FEM data closer to the normalized variance determined by simulations under idealized conditions. Furthermore, preliminary results indicate that the medium range order length scale extracted from the pair-persistence analysis used in FEM is strongly affected by energy filtering.

Within the last decade, spintronics and magnonics have demonstrated an impressive development in the experimental realization of Boolean logic gates. However, the exponential growth of data and the rise of the internet of things are pushing the deterministic Boolean computing of von-Neumann architectures to their limits or simply consume too much energy. Moreover, conventional Boolean computer architectures are likely to remain inefficient for certain cognitive tasks in which the human brain excels, such as pattern recognition, particularly when incomplete or noisy data are involved.
One of the most generic and abstract implementations of brain-inspired computing schemes is reservoir computing, which uses the nonlinearity and recurrence of a physical system to separate patterns of time series data into distinct manifolds of a higher dimensional output space. In this presentation, I will demonstrate the experimental realization of pattern recognition based on reservoir computing using magnons.
Recently, we reported on the nonlinear scattering of magnons in vortices in micron-sized NiFe discs [1] which we learned to control and stimulate by means of other magnons [2]. Now, we utilize these phenomena to employ magnons for pattern recognition without relying on magnon transport in real space. I will present a comprehensive overview of experimental results and numerical simulations demonstrating the capabilities and advantages of magnon reservoir computing in reciprocal space.
[1] K. Schultheiss, et al. Physical Review Letters 122, 097202 (2019)
[2] L. Körber, et al. Physical Review Letters 125, 207203 (2020)

The short presentation introduces the Helmholtz Institute Freiberg for Resource Technology, its vision and mission as well as its research foci to an international audience.

Die EU muss zum eigenständigen Rohstoff-Player werden. Sonst steht es schlecht um Versorgungssicherheit und grüne Energiewende, argumentieren Jakob Kullik und Jens
Gutzmer.

This study shows residual surface-C’s influence on photocathodes’ quantum efficiency based on p-GaN grown on sapphire by metal organic chemical vapor deposition. An X-ray photoelectron spectrometer (XPS) built in an ultrahigh vacuum system allowed the in-situ monitoring of the photocathode surface beginning immediately after their cleaning and throughout the activation and degradation processes. An atomically clean surface is necessary to achieve a negative electron affinity, which is the main prerequisite for high quantum efficiency. The p-GaN samples were cleaned with ethanol and underwent a sub-sequential thermal vacuum cleaning. Although carbon and oxygen contaminations, undesired impurities from the metal organic chemical vapor deposition, remained on the surface, p-GaN could still form a negative electron affinity surface when exclusively activated with cesium. After the activation with cesium, a shift to a higher binding energy of the photoemission peaks was observed, and a new species, a so-called cesium carbide, was formed, growing over time. The XPS data allowed elucidating the critical role of these cesium carbide species in photocathode degradation.
The X-ray damage to the p-GaN:Cs photocathodes, especially the influence on the cesium, was additionally discussed.

This paper compares different photocathodes that are applicable for electron injector systems and
summarizes the development in cathode technology in the last years. The photocathode is one of
the key components of the facilities that provides electrons for many research experiments. Typically,
a high efficiency and a long operation time are desired, thus the photocathode needs to be
robust against any rest gases occasionally available during operation. Low thermal emittance and
fast response time are special requirements for the accelerator community. These parameters are
commonly used to compare the various cathode materials. Metals and plasmon-enhanced materials
emit electrons from the near surface, whereas semiconductors emit photoelectrons mostly from the
bulk region.
We compare metal photocathodes such as magnesium, copper and lead, with semiconductor photocathodes
such as cesium telluride, antimonide photocathodes and III-V semiconductor photocathodes.
GaAs and its typical application for the generation of spin-polarized electrons is discussed and
special attention has been paid to the emerging GaN as a potential novel photocathode. The above
mentioned state-of-the-art cathodes are compared regarding their preparation approaches, quantum
efficiency, lifetime, response time and their status of application. This work is aimed to provide
a guideline for particle accelerator researchers in their choice of the cathode material. Thermionic
cathodes and field emission cathodes are not discussed in this review.

In contrast to thermodynamic databases for modeling aquatic species or solid phase solubility, the development of databases with surface complexation data (SCM) for modeling sorption is not well advanced. This is due to the nature of sorption modeling, which ranges over a multitude of competing models and a wide variation of surface complexities. In addition to the RES³T SCM database or the JAEA Kd database, the data are mainly available as individual publications or books with a small amount of data. The talk addresses the logical requirements of a reference database for sorption data and quality assurance with respect to the assumed surface species.

Ag-bearing pyrrhotites Fe1-xS were synthesized using the salt flux technique. The concentration of Ag
in pyrrhotite reached 0.08 wt.% at 540 °C and 1.3 wt.% at 750-760 °C. SEM and EPMA analyses
revealed that at low sulfur fugacity (CFe > 48.8 at.%), Ag is disseminated in pyrrhotites in an
“invisible” form and concentrates on the grain boundaries of crystals as metallic rims (group (i)). At
high sulfur fugacity (CFe < 48.8 at.%), Ag occurs as a minor form of Ag-bearing oriented submicron
inclusions but mostly enriches pyrrhotite as the “invisible” form disseminated in the pyrrhotite matrix
(group (ii)). Analysis of Ag K-edge XANES spectra recorded at ambient temperature revealed that
pyrrhotites of group (i) mostly contain Ag°, group (ii) accommodate Ag as Ag+. EXAFS spectra fitting
demonstrated that samples of group (i) contain a small fraction of the “invisible” form while the
majority of Ag is disseminated in pyrrhotite crystals as Ag°; samples of group (ii) mostly contain the
“invisible” form presented by Ag+2S-like clusters. Heating of the samples containing the “invisible”
form of Ag up to 750 °C performed via capillary technique demonstrated the decrease of Ag
coordination number in the second coordination sphere and increase of Debye-Waller parameters for
Ag and Fe in the distant coordination shells. This observation demonstrates that the size of Ag2S-like
form is decreasing with temperature. However, the “invisible” Ag presented by Ag2S-like clusters is
stable up to the temperature of synthesis of 750 °C, hence, the formation of clusters cannot be
accounted for upon cooling. The predicted concentrations of Ag in pyrrhotite coincide with those from
natural samples of various origins.

Dieser Beitrag wurde als eingeladener Vortrag für das 25. Internationale Leichtbausymposium in Dresden erstellt. Es gibt hierzu keine Schriftform.

Die Herausforderungen des menschengemachten Klimawandels in Kombination mit rasanten Fortschritten im Bereich der digitalen Technologien erfordern eine gigantische stoffliche Zeitenwende. Das Zeitalter der Kohlenwasserstoffe neigt sich dem Ende zu – es wird abgelöst von einem Zeitalter der mineralischen und metallischen Rohstoffe. Ohne die nachhaltige und zuverlässige Verfügbarkeit einer Vielzahl von anorganischen Rohstoffen, von Antimon bis Yttrium, können weder das angestrebte Energiesystem – basierend weitgehend auf der Nutzung erneuerbarer Energiequellen - noch die aktuelle volkswirtschaftliche Ausrichtung der Bundesrepublik Deutschland und der Europäischen Union in Zukunft funktionieren. Dabei betrifft der zu erwartende, massive Anstieg des Bedarfs sowohl Massenrohstoffe wie Aluminium oder Kupfer, als auch die viel zitierten Hochtechnologiemetalle, wie zum Beispiel die Seltenen Erden oder Indium.

Um den zukünftigen Rohstoffbedarf abdecken zu können müssen eine Reihe komplementärer Handlungsoptionen komplementär wirken. So ist die weitmöglichste Schließung von Wertstoffkreisläufen zumindest gleichrangig zu betrachten neben der ressourcen- und energieeffizienten Gewinnung primärer Rohstoffe. Beide sind essentielle Bausteine einer nachhaltigen Kreislaufwirtschaft. Auch sollte die Nutzung heimischer Rohstoffpotentiale ähnlichen Status haben wie der Import von Rohstoffen über globale Lieferketten. Die Konsequenzen der Rohstoffnutzung dürfen nicht weiter einseitig externalisiert werden. Technologien zur effizienten Rohstoffverarbeitung und -nutzung müssen genau so entwickelt werden wie das Verständnis von Politik und Gesellschaft für die Notwendigkeit einer funktionierenden Rohstoffversorgung. Die Rohstoffversorgung muss ein wichtiger Faktor für die internationale Positionierung der EU werden. Für die EU bedeutet dies ein stärkeres Engagement in Rohstofffragen, um die eigenen strategischen Doppelziele (European Green Deal und Digitalisierung) erreichen zu können. Um all dies zu erreichen erscheint es notwendig, dass die strategischen, industriellen und gesellschaftlichen Aspekte der Rohstoffversorgung auf nationaler und europäischer Ebene eine sehr viel prominentere Rolle zugewiesen wird. Nur so erscheint es möglich, geeignete Kompromisse zu finden und nachhaltige Lösungen für die Rohstoffversorgung der Zukunft zu definieren.

For several decades, there has been a widely accepted paradigm that „Germany is rich in poor ore deposits“. This paradigm was communicated with conviction especially by experts, i.e. geoscientists active in the raw materials sector. And, indeed, this paradigm appeared well justified as the known endowment of Germany in bulk commodities such as iron, manganese or copper was small in resource tonnage and of too low grade in comparison to world-class deposits in countries such as Australia, South Africa or Chile. Yet, from today’s perspective there are some sound arguments why this paradigm may be outdated. Tangible reasons include (a) a marked shift in the portfolio of mineral commodities that are in the focus of a global raw materials industry that needs to generate the supply needed to meet the ambitious goals of the energy transition sensu lato; (b) the almost complete lack of modern mineral exploration across most of Germany for more than 30 years – and thus a sincere lack of knowledge about mineral endowment in the subsurface environment; (c) the well-recognised need to render global mineral exploration and production more sustainable. These arguments, combined with the well-known exceptional mineral endowment of regions such as the Erzgebirge or the Kupferschiefer basin across central and south-eastern Germany provide motivation to revise the widely held paradigm. Germans should, indeed, today be regarded as a highly prospective and attractive exploration frontier located in the heart of Europe.

This paper investigates one aspect of surface air nucleation in froth flotation, namely the impact of frother-type surfactants like Methyl isobutyl carbinol (MIBC). During this study, tap water was pressurized in an autoclave to produce air-oversaturated water for air nucleation precondition in flotation. Various experiments were carried out with graphite particles to investigate the influences of gas nucleation and MIBC on flotation: micro-flotation, single bubble collision experiments in hydrodynamic conditions and pick-up experiments in static conditions. In addition, microscopic observations were combined with agglomeration analysis to clarify the effects of the frother MIBC on the air nucleation and agglomerate formation. The experimental results show the combination of MIBC and air nucleation can significantly increase the graphite recovery compared to using air-oversaturated water or normal tap water with MIBC alone, respectively. The analysis indicates that MIBC can improve the air nucleation probability on graphite surfaces by enhancing the stability of the air nuclei to form more microbubbles on the surface. Meanwhile, the surface microbubbles can collide with other particles forming coarser aggregates, improving their collision probability and with this increasing the recovery of fine particles. Furthermore, the results show that MIBC can reduce the detachment of particles from the surface of nucleation bubbles, leading to an increase in particle load of the bubble-particle aggregates in hydrodynamic conditions, improving the graphite recovery significantly.

Dieser Beitrag ist ein eingeladener Vortrag zu einer Festveranstaltung anlässlich der Freischaltung des DIGA.Sax Datenportals.

The n-type doping of Ge is a self-limiting process due to the formation of vacancy-donor complexes (DnV with n ≤ 4) that deactivates the donors. Based on data density functional theory calculations, at temperature higher than 850 K, the concentration of D4V clusters progressively decreases liberating unbounded vacancies and donor atoms. Similar problems apply to wide-band gap semiconductors where the p-type doping is challenging, mainly due to the high activation energy for acceptors, low equilibrium solid solubility and deactivation of acceptors by the formation of acceptor-vacancy clusters. Here, we report on experiments and theoretical calculations solving the basic problem of donors and acceptors deactivation in heavily doped semiconductors. The dissolution of donor/acceptor-vacancy clusters in heavily doped semiconductors is achieved by ms-range FLA with a peak temperature close to the melting point of the semiconductor. Positron annihilation lifetime spectroscopy (PALS) reveals that dopant-vacancy clusters are the main defect centers deactivating both acceptors and donors. Millisecond-range high-temperature treatment dissociates the dopant-V clusters and, as shown by SIMS, fully suppresses the dopant diffusion in both group IV semiconductors and III-V compound semiconductors. For the first time, using structural characterization (PALS, SIMS) and electrochemical capacitance-voltage profiling combined with DFT calculations, we were able to address, understand, and solve the fundamental problem hindering the doping of semiconductors above the solid solubility limit.

We present a frequency-domain study of the dynamic behavior of a magnetic vortex core within a single Permalloy disk by means of electrical detection and micromagnetic simulations. When exciting the vortex core dynamics in a nonlinear regime, the lineshape of the rectified dc signal reveals a resonance peak splitting which depends on the excitation amplitude. Using micromagnetic simulations, we show that at high excitation power the peak splitting originates from the nanosecond time scale quasiperiodic switching of the vortex core polarity. Using lock-in detection, the rectified voltage is integrated over a ms time scale, so that the net signal detected between the two resonant peaks for a given range of parameters cancels out. The results are in agreement with the reported effects of the in-plane static field magnitude on the gyration dynamics, and complement them by detailed analysis of the effects of the rf current amplitude and the azimuthal angle of the in-plane bias magnetic field. Systematic characterization shows that a transition from linear to nonlinear dynamical regime can be controlled by rf current as well as by varying the magnitude and the direction of the bias magnetic field.

The mining industry generates large amounts of tailings every year. The most common destination for the tailings is deposition in tailings storage facilities (TSFs), which can have normous dimensions. The management and storage of such large volumes of material pose many challenges in terms of dam stability and immobilization of hazardous contaminants that represent
human-health and environmental risks, particularly for sulfide-containing materials. In addition, considerable amounts of precious and base metals can be lost in the tailings. Due to the economic value and growing industrial demand for precious and base metals, tailings may therefore be potential sources of secondary raw materials. This contribution investigates the flotation of pyrite-rich tailings, containing residual chalcopyrite, galena, and sphalerite, and high amounts of ultrafine particles. Flotation was used to recover the sulfide minerals and generate tailings with low sulfur content. The Cu-Pb-Zn-rich product could go to further treatment (e.g. (bio)hydrometallurgy) to recover the metals, while the low sulfur fraction could be used in the civil construction industry. Automated mineralogy (MLA) was used to provide quantitative mineralogical and textural data. Bench-scale experiments were performed by combining classic flotation and floc flotation (flotation of flocs of targeted minerals). Flotation of the material as received, as well as after classification into two fractions was performed. The samples as received and the coarser fraction (+37 µm) underwent classic flotation, while the finer fraction (-37 µm) was processed either by using the classic or the floc flotation approach. The flotation of the coarser particles provided higher sulfide recoveries, higher combined Cu-Pb-Zn grades in the concentrate (3.66 %), cleaner residues (1.6 % S), faster flotation rates, and a reduced reagent consumption. Likewise, the results from the fine particle flotation allowed lower S content in the residues (3.4 % S) as compared to the flotation of the original material. The results of the use of floc flotation for the finer fraction show an increase in the mass pull with a slight increase in the recovery of sulfides. Overall the development of a route to process the tailings proved to be promising and the use of a two-route approach indicates advantages as compared to a single route.

A series of CuCr₂O₄ thin films has been successfully synthesized via a facile and cost-effective reactive Direct Current Magnetron Sputtering technique at room temperature. These coatings were deposited to evaluate their suitability as absorber material for the next generation of concentrated solar power plants [1]. The composition of the films was controlled using as key parameters the power ratio between Cu and Cr targets as well as the oxygen flux. The films deposited without intentional substrate heating were initially amorphous and needed to be annealed at 800 °C for one hour to obtain a spinel-like crystal structure [2]. RBS was used to characterize the composition of the as-deposited and annealed coatings. The structural properties were investigated by Raman spectroscopy and XRD. Structural characterization allows us to evidence that slight deviation in stoichiometry promotes the formation of secondary phases in the films. In this concern, we use in-situ Raman spectroscopy and spectroscopic ellipsometry to characterize the structural evolution of the films as a function of temperature in a controlled oxygen atmosphere. The study evidences the evolution from amorphous to fully crystallized material. Additionally, the influence of the film roughness in the optical performance of the coatings with appropriate composition was explored to enhance the optical properties of the film.

References:

1) Ramón Escobar Galindo, Matthias Krause, K. Niranjan and Harish Barshilia, in Sustainable Material Solutions for Solar Energy Technologies (ed. Mariana Fraga, Delaina Amos, Savas Sonmezoglu, Velumani Subramaniam, Elsevier, 2021).
2) Matthias Krause, Johanna Sonnenberg, Frans Munnik, Jörg Grenzer, René Hübner, Aurelio Garcia-Valenzuela, Sibylle Gemming in Materialia 18 (2021) 101156.

The efficient integration of 2D materials, like graphene, transition metal dichalcogenides (TMDs) and h-BN into the current electronic device technology requires mastering the techniques of effective tuning of their optical, electronic and magnetic properties. It is crucial to understand how we can tune their conductivity (e.g. n-type or p-type doping), induced ferromagnetism, or valley polarization. For the conventional bulk semiconductors, ion implantation is the most developed method to do this.
In this work, we have investigated the optical and structural properties of different TMDCs modified by ion implantation. We have demonstrated the applicability of ion implantation and post-implantation non-equilibrium thermal processing for tuning the carrier concentration in 2D materials. We demonstrate p-type and n-type doping in TMDCs flakes (starting with 1 ML) realized by low-energy ion implantation of P+ and Cl+ ions through a thin capping layer followed by millisecond-range flash lamp annealing (FLA). We further show that FLA for 3 ms is enough to recrystallize implanted MoSe2 and remove ion induced defects.
The comparison between the density functional theory calculations and experimental temperature-dependent micro-Raman spectroscopy data indicates that Cl atoms are incorporated into the atomic network of MoSe2 as substitutional donor impurities. Our results clearly indicate that using our experimental approach, the conventional ion implanters can easily be used to modify the optical, electronic and magnetic properties of various 2D materials on demand

The n-type doping of Ge is a self-limiting process due to the formation of vacancy-donor complexes (Dn-V with n ≤ 4) that deactivates the donors. Based on data density functional theory calculations, at temperature higher than 850 K, the concentration of D4-V clusters progressively decreases liberating unbounded vacancies and donor atoms. Next the free monovacancies are trapped by big vacancy clusters causing high activation efficiency of donors in Ge. Similar problems apply to III-V compound semiconductors, where, e.g. in GaN the p-type doping is challenging, or highly n-type layer formation in GaAs. That is mainly due to the high activation energy for acceptors, low equilibrium solid solubility and deactivation of dopants by the formation of dopant-vacancy clusters. Here, we report on experiments and theoretical calculations solving the basic problem of donors and acceptors deactivation in heavily doped semiconductors. The dissolution of donor/acceptor-vacancy clusters in heavily doped semiconductors is achieved by ms-range FLA with a peak temperature close to the melting point of the semiconductor. Positron annihilation lifetime spectroscopy (PALS) reveals that dopant-vacancy clusters are the main defect centers deactivating both acceptors and donors. Millisecond-range high-temperature treatment dissociates the dopant-V clusters and, as shown by SIMS, fully suppresses the dopant diffusion in both group IV semiconductors and III-V compound semiconductors. For the first time, using structural characterization (PALS, SIMS) and electrochemical capacitance-voltage profiling combined with DFT calculations, we were able to address, understand, and solve the fundamental problem hindering the doping of semiconductors above the solid solubility limit.

In this study, synthetic pure cassiterite and cassiterite doped with two different Fe contents were successfully recrystallized by means of sintering. Their crystal structure and chemical compositions are characterized by X-ray powder diffraction (XRD) as well as scanning electron microscopy (SEM) combined with energy-dispersive X-ray (EDX) analysis. Their floatability was studied by microflotation with a diphosphonic acid surfactant named Lauraphos301 as a collector. Unlike the addition of ferric ions in solution, which strongly depressed the floatability of all the cassiterite samples, a much higher flotation efficiency of the Fe-doped cassiterite samples was found especially at lower collector concentrations. The cassiterite floatability is proportional to the Fe content in the cassiterite at a broad range of pH, and the recovery has the following order: Cassiterite with 1417 ppm Fe > cassiterite with 1165 ppm Fe > pure cassiterite The electrokinetic behavior of the cassiterite samples with and without the collector was studied by electrophoretic measurements and revealed that the chemical interaction dominated the adsorption. With the help of the particle shape analysis, a more angular shape was found for the Fe-doped cassiterite samples. Moreover, without the influence of particle shape, much abundant adsorption of Lauraphos301 was found on the Fe-doped cassiterite samples by AFM topography imaging. The minor amount of Fe in the cassiterite lattice as well as a more angular shape of the Fe-doped cassiterite samples were believed to enhance floatability collectively. The study reveals that the influence of the chemical composition of the minerals on flotation was almost inextricably bound up with particle morphology and emphasizes the importance of considering both factors and investigating them individually for the flotation study.

Indistinguishable single-photon sources at telecom wavelengths are the key photonic qubits for transmitting quantum information over long distances in standard optical fibers with minimal transmission losses and high fidelity. This enables secure quantum communication over the quantum internet and, in turn, a modular approach to quantum computing. The monolithic integration of single-photon sources with reconfigurable photonic elements and single-photon detectors in a silicon chip is a key enabling step toward demonstrating scalable quantum hardware such as quantum photonic integrated circuits (QPICs). Nowadays, nearly all the necessary components for QPICs are available such as superconducting single-photon detectors, low-loss photonic waveguides, delay lines, modulators, phase shifters, and low-latency electronics. Yet, the practical implementation of scalable quantum hardware has been largely hampered by the lack of on-chip single-photon emitters in silicon that can be created at desired locations on the nanoscale.
Here, we demonstrate two complementary wafer-level protocols for the creation of single telecom-wavelength color centers in silicon with a probability exceeding 50%. Both approaches are fully compatible with current silicon technology and enable the scalability of millions of single telecom quantum emitters that are created at desired nanoscale positions on a silicon chip. These results unlock a clear pathway for industrial-scale QPICs.

The aggressive reduction of the channel length in transistors needs the high doping of the channel region, while the contact area requires doping beyond 1020 cm-3 to ensure low-resistance ohmic contacts. Similar problems apply to wide-band gap semiconductors where the p-type doping is challenging, mainly due to the high activation energy for acceptors, low equilibrium solid solubility and deactivation of acceptors by the formation of acceptor-vacancy clusters. Recently, we have shown that ultra-doped n-type and p-type Ge with a carrier concentration above 1020 cm-3 can be achieved by applying non-equilibrium methods like ion implantation followed by millisecond-range flash-lamp annealing (FLA) [1-3]. The n-type doping of Ge is a self-limiting process due to the formation of vacancy-donor complexes (DnV with n ≤ 4) that deactivates the donors [4]. Based on data density functional theory calculations, at temperature higher than 850 K, the concentration of D4V clusters progressively decreases liberating unbounded vacancies and donor atoms. The same effect is observed for p-type Ge and in III-V semiconductors. Here, we report on experiments and theoretical calculations solving the basic problem of donors and acceptors deactivation in heavily doped semiconductors. The dissolution of donor/acceptor-vacancy clusters in heavily doped semiconductors is achieved by ms-range FLA with a peak temperature close to the melting point of the semiconductor. Positron annihilation lifetime spectroscopy (PALS) reveals that dopant-vacancy clusters are the main defect centers deactivating both acceptors and donors. Millisecond-range high-temperature treatment dissociates the dopant-V clusters and, as shown by SIMS, fully suppresses the dopant diffusion in both group IV semiconductors and III-V compound semiconductors. For the first time, using structural characterization (PALS, SIMS) and electrochemical capacitance-voltage profiling combined with DFT calculations, we were able to address, understand, and solve the fundamental problem hindering the doping of semiconductors above the solid solubility limit.

Indistinguishable single-photon sources at telecom wavelengths are the key photonic qubits for transmitting quantum information over long distances in standard optical fibers with minimal transmission losses and high fidelity. This enables secure quantum communication over the quantum internet and, in turn, a modular approach to quantum computing. The monolithic integration of single-photon sources with reconfigurable photonic elements and single-photon detectors in a silicon chip is a key enabling step toward demonstrating scalable quantum hardware such as quantum photonic integrated circuits (QPICs). Nowadays, nearly all the necessary components for QPICs are available such as superconducting single-photon detectors, low-loss photonic waveguides, delay lines, modulators, phase shifters, and low-latency electronics. Yet, the practical implementation of scalable quantum hardware has been largely hampered by the lack of on-chip single-photon emitters in silicon that can be created at desired locations on the nanoscale.
Here, we demonstrate two complementary wafer-scale protocols for the quasi-deterministic creation of single G and W telecom-wavelength color centers in silicon with a probability exceeding 50%. Both approaches are fully compatible with current silicon technology and enable the fabrication of single telecom quantum emitters at desired nanoscale positions on a silicon chip. These results unlock a clear and easily exploitable pathway for industrial-scale photonic quantum processors with technology nodes below 100 nm.

In this paper we present an experimental study of SOI UTBB n-MOSFETs at cryogenic temperatures. The device employs fully silicided source/drain with dopant segregation formed by “Implantation Into Silicide” (IIS) process. The impact of the back-gate (Vback) on the device performance is systematically investigated. The results demonstrate that Vback is essential to tune the threshold voltage Vth. And optimization of Vback values can improve the subthreshold swing (SS), Drain-Induced Barrier Lowering (DIBL), transconductance Gm and mobility at cryogenic temperatures, providing a potential to fulfill the ultra-low power requirement for quantum computing application.

Photogenerated carriers' transfer efficiency as one of the most important criteria determines the efficiency of a photoanode for photoelectrochemical (PEC) water splitting. Energy barrier-free charge transfer of photogenerated carriers is achieved in a core–shell heterostructure of Bi2S3/ZnS:Co/TiO2, in which the arrayed TiO2 nanorods are covered with the Co doped ZnS inner layer and the Bi2S3 outer layer. The dual-shell structure ensures high photoconversion efficiency in PEC water splitting. The impurity energy state of Co in ZnS connects the conduction band edges of Bi2S3 and TiO2 to convey photogenerated electrons, without electrons hopping to Zn orbits at higher energy positions. The ABPE value of 1.07% at 1.23 V vs. RHE demonstrates the improved photoconversion efficiency of Bi2S3/ZnS:Co/TiO2 heterostructure. This work offers a photoanode construction strategy for the enhancement of the PEC water splitting via introducing impurity energy states at interlayer for barrier-free photogenerated charge migrating.

The attachment of bubbles and particles represents one of the sub-processes in froth flotation among others (e.g. collision and detachment). The main interactions present at short distances in such a bubble-particle system are the van der Waals and electrostatic double layer interactions combined in the DLVO theory. In this study, the special features of the attachment process were discussed with a focus on flotation. For the van der Waals interactions, the Hamaker constants were calculated with the help of Lifshitz´ macroscopic theory as a function of the separation distance for specific material combinations. A specific material system (PbS-Water-Air) was used to demonstrate the implementation of bubble-particle attachment of the proposed modelling framework. The effects of additional surfactant/collector and air layers on the solid interface were presented. This framework of layered systems showed that the sign of van der Waals interaction could be turned from repulsive to attractive without the need to extend the DLVO theory. The thickness of the layer as a function of collector adsorption between a particle and a bubble is suggested as a modelling parameter in bubble-particle attachment efficiency.

Laser-wakefield accelerators, providing high-energy electrons on a small scale, are promising alternatives to conventional particle accelerators. High field gradients in the regime of several GeV/m grant significant energy gain already in the range of millimeters and therefore table-top applications of LWFA are feasible.
Nevertheless, improving the beam quality is essential for future applications. With the development of particle-in-cell (PIC) algorithms, a time resolved analysis of plasma based accelerators became available, providing a steady optimisation potential of the electron beam. Using the PIC code PIConGPU, the influence of a density down-ramp on the characteristic Courant-Snyder parameters and the evolution fundamental beam properties is presented in this work. Through the visualisation of these quantities on the millimeter scale of the plasma, the oscillation of the beam parameters and the expansion of the beam waist in the down-ramp region can be demonstrated and furthermore, the average energy and total amount of charge in the main electron bunch is determined at the end of each plasma stage.
Thus, a detailed discussion of the down-ramp influence on the Courant-Snyder parameters, the bunch-charge and the beam energy, is provided for every simulation. Comparing the results with a reference simulation reveals optimisation possibilities of all mentioned parameters.
It is shown, that a perfectly matched beam is not yet reached for the assumed setup, but still an optimal density profile, combining low beam divergence and high energy and bunch charge, is suggested in the end of this work.

The bonding structure of tin oxide (SnOx) films grown by reactive DC magnetron sputtering has been studied by the combination of X-ray diffraction (XRD) and soft X-ray absorption near-edge structure (XANES). The oxygen incorporation in the films has been controlled by the O2 partial pressure (PO2) in the O2/Ar discharge mixture. In addition, the impact of substrate heating and post-deposition flash lamp annealing (FLA) on crystal growth has been studied. In general, it has been stablished a transition from SnO to SnO2 arrangements by increasing PO2, where XRD and XANES provide complementary results about the formation of single- and mixed-phase films. In samples produced at room temperature, XANES gives unique information about such structural evolution, as well as related to defects like the incorporation of O2 molecules at high PO2. FLA on samples grown at room temperature promotes crystal growth and the phase evolution follows the initial structural selectivity. Finally, the optical properties and surface morphology of the films have been correlated with the structural identification.

Tractography is a method that can be seen as a supplement to conventional imaging modalities of the brain. It is of relevance to different research and clinical areas, including pre-surgical planning for epilepsy. Although tractography was heavily researched in the past, there is no gold standard for algorithms, processing or interpretation of results. For reliable practical usage, better methods for calibrations of parameters have to be found.
This thesis aims to provide information about parameters of two different tractography algorithms, by determining the sensitivity of connectivity, measured as weighted streamline counts and the sensitivity of low-level geometry, measured as streamline densities and main tract directions, towards parameter variations. The analysis is done locally, using a reference constellation of parameters that made use of default values proposed by other researchers and a small prior qualitative assessment.
Analysis was successful for the parameters "cutoff" and "maximum fiber length" of the algorithm iFOD2, but showed several limitations for other parameters. In contrast, the parameters "maximum attempts" and "trials" of iFOD2 did not affect connectivity on a local scale more than chance. Similarly, the parameters "start temperature", "end temperature" and "iterations" of the Global Gibbs tractography were found to be irrelevant for both connection and low-level geometry. These findings may allow for dimensionality reduction. However, this would have to be confirmed through further investigation.

Proteins carry out the algorithms of life. As such, they play an integral role in Systems biology. Given the rapid development of Systems biology, understanding biological processes at a molecular level has become more important to other disciplines, like medicine, as well. Yet, current didactic methods often fail to teach their students biochemistry effectively. We present the Protein Forge, a Virtual Reality application that aims to help primarily medical students to identify amino acids, the building blocks of proteins, and to teach them how those amino acids are chemically linked. The program follows a predefined workflow: its user identifies amino acids from a naturally occurring protein sequence one after the other. When choosing the right amino acid, the user is presented with an animation, showing the formation of a peptide bond, i.e., the bond between two amino acids. The program was implemented in scenery, an open-source framework for rendering VR scenes. To display amino acids, we developed a rudimentary molecular viewer for scenery, consisting of a data structure to store the molecule data and an algorithm to determine the atom positions in space for a given molecule. A video of the experience can be found here:https://cloudstore. zih.tu-dresden.de/index.php/s/JB898wJFgp2r6fT, the respective code here: https:// github.com/scenerygraphics/scenery/tree/peptide_chain.

trx-jvm is a library implementing TRX (say, tee-ar-ex) file reading for JVM-based languages. TRX is a novel, open-source format for storing tractography data. trx-jvm was written with performance in mind, and uses imglib2 CellImgs for large array storage and access. It is able to parse and load a 4 GiB TRX file with 500000 streamlines in about 18 seconds on a standard notebook.

We present a content-adaptive generation and parallel compositing algorithm for view-dependent explorable representations of large three-dimensional volume data. Large distributed volume data are routinely produced in both numerical simulations and experiments, yet it remains challenging to visualize them at smooth, interactive frame rates. Volumetric Depth Images (VDIs), view-dependent piece wise-constant representations of volume data, offer a potential solution: they are more compact and less expensive to render than the original data. So far, however, there is no method to generate such representations on distributed data and to automatically adapt the representation to the contents of the data. We propose an approach that addresses both issues by enabling sort-last parallel generation of VDIs with content-adaptive parameters. The resulting VDIs can be streamed for display, providing responsive visualization of large, potentially distributed, volume data.

We present an efficient raycasting-based rendering algorithm for view-dependent piecewise constant representations of volumetric data. Our algorithm leverages the properties of perspective projection to simplify intersections of rays with the view-dependent frustums that form part of these representations. It also leverages spatial homogeneity in the underlying volume data to minimize memory accesses. We further introduce techniques for skipping empty-space and for dynamic subsampling for accelerated approximate renderings at controlled frame rates. Benchmarks show that responsive frame rates can be achieved close to the viewpoint of generation for HD display resolutions, while providing high-fidelity approximate renderings of Gigabyte-sized volumes.

The CellxGene project has enabled access to single-cell data in the scientific community, providing tools for browsed-based no-code analysis of more than 500 annotated datasets. However, single-cell data requires dimensional reduction to visualize, and 2D embedding does not take full advantage of three-dimensional human spatial understanding and cognition. Compared to a 2D visualization that could potentially hide gene expression patterns, 3D Virtual Reality may enable researchers to make better use of the information contained within the datasets. For this purpose, we present \emph{Corvo}, a fully free and open-source software tool that takes the visualization and analysis of CellxGene single-cell datasets to 3D Virtual Reality. Similar to CellxGene, Corvo takes a no-code approach for the end user, but also offers multimodal user input to facilitate fast navigation and analysis, and is interoperable with the existing Python data science ecosystem. In this paper, we explain the design goals of Corvo, detail its approach to the Virtual Reality visualization and analysis of single-cell data, and briefly discuss limitations and future extensions.

The impact of the core mass on the compact/neutron-star mass-radius relation is studied.
Besides the mass, the core is parameterized by its radius and surface pressure, which supports the outside one-component Standard Model (SM) matter.
The core may accommodate SM matter with unspecified (or poorly known) equation-of-state or several components, e.g.\ consisting of admixtures of Dark Matter and/or Mirror World matter etc.\ beyond the SM. Thus, the admissible range of masses and radii of compact stars can be considerably extended.

Ptychography is a computational imaging method used to numerically retrieve the projection of an object from a set of measured diffraction patterns. Each diffraction pattern represents a partially overlapping area of the object. The corresponding inverse problem, i.e. the image reconstruction, can be solved by projection-based or gradient-based algorithms. However, existing implementations are usually optimized for a specific system and therefore difficult to port to new systems. To solve this problem, we will be introducing the alpaka library with a generic C++ interface to implement an algorithm one time and execute it on different target platforms, like CPUs and GPUs from different vendors. First, we ported an existing algorithm, implemented in CUDA C++, to alpaka to demonstrate the workflow and advantages. Then, we implemented another algorithm from scratch to obtain the software requirements for an easy and fast development cycle of alpaka based image reconstruction applications.

Software engineers form the CASUS Professional Support Team from diverse scientific backgrounds, including computer science, data science, and physics. With this team, the CASUS institute provides an appropriate setting for the sustainable and long-term development of scientific software, rather than being bound to the lifetime and funding of single projects.
For a digital institute focused on a cross-domain exploration of complex systems – often only possible by computational means – putting software engineering at eye level with research ensures a reliable base of high-quality software. We emphasize open-source solutions, reusability, documentation, and portability, as well as on F.A.I.R. data.
The Professional Support Team is involved in numerous in-house and cross-institutional projects:
The scientific Python packages MALA and atoMEC are supported in the long term by code reviews, documentation generation, package management and continuous integration.
The performance-portability framework Alpaka has given established physics simulations such as PIConGPU the chance to port to next-gen Exascale HPC systems such as ORNL Frontier. It is also used by emerging simulation and data analysis projects at CERN.
The pandemic research platform Where2Test consists of several web applications linked to a central database containing current epidemiologic data. Predictions calculated on the HPC cluster are automatically post-processed and published online.
Open software attracts collaboration, as the scientific I/O library openPMD-api shows, developed in collaboration between CASUS and LBNL and used by numerous scientific projects in Europe and America.
With OPTIMA and PIONEER cloud-based platforms, the CASUS institute provides data access and analytic capabilities for researchers and pharmaceutical companies in a federated way.
The poster shows the diverse skills found within the Professional Support Team, representing the interdisciplinary nature of CASUS, and briefly introduces the projects our team is involved in.

Broschüre des Helmholtz-Instituts Freiberg für Ressourcentechnologie anlässlich seines 10-jährigen Bestehens im Jahr 2021. Die Broschüre resümiert die wissenschaftliche und quantitative Entwicklung des Instituts von der Gründung im Jahr 2011 bis 2021. Die Beiträge geben einen Überblick über die verschiedenen Kernkompetenzen des Instituts sowie über Highlight-Projekte. Darüber hinaus wird ein Ausblick auf zukünftige Entwicklungen und Projekte gegeben.

Brochure of the Helmholtz Institute Freiberg für Resource Technology on occasion of its 10th anniversary in 2021. The brochure resumes the scientific and quantitative development of the institute from its foundation in 2011 to 2021. The articles give an overview on the various key competencies of the institute as well as on highlight projects. Furthermore an outlook on future developents and projects is given.

Liquid maldistribution causes severe loss of separation performance in packed distillation columns. Thus, the investigation of liquid distribution is of particular interest in academia and industry, especially the initial liquid distribution. Liquid maldistribution is present not only in packed distillation columns but also in process intensification equipment such as rotating packed beds (RPBs), which may be operated with metal foam packings. The loss of separation performance is severe especially in multi-rotor RPBs with single-block packing as these lack in liquid distributors in the lower rotor(s). Conventional liquid distribution via nozzles is difficult to implement in the lower rotors. For this reason, a liquid distributor for the lower rotors has been developed and denoted ‘rotating baffle distributor’ (RBD). The RBD resembles a rotary atomizer and is directly mounted to the rotor.

In summary, the RBD design was successfully applied in a 2 rotor RPB in combination with a liquid collector at the intermediate floor. We present a proven concept of numbering up rotors in RPB machines to accomplish separations that cannot be performed in a single rotor due to the limiting number of theoretical stages.

Electrons from laser wakefield accelerators (LWFA) can be ultrashort and quasi-monoenergetic. They have the potential to be an ideal source for advanced light sources or beam drivers for hybrid laser-plasma wakefield accelerators (LPWFA). A wide variety of injection methods have already been developed to produce high-quality LWFA electrons. However, such high-quality electron bunches may degrade upon exiting the LWFA stage.

This poster addresses quality-preserving methods for extracting electron beams from laser wakefield accelerators by adjusting the plasma density of the down ramp. By modeling different gas profiles with the fully relativistic particle-in-cell code PIConGPU, not only the final beam quality but also all relevant physical effects can be studied in detail. This allows not only to find an optimal quality-preserving down ramp but also to study the influence of changes in laser focus position on beam properties during extraction.

Axial heterostructures have diverse functionality in electronic and optoelectronic devices. Implementing such systems in freestanding semiconducting nanowires further broadens the scope of potential applications, for example: distributed Bragg reflectors, high-efficiency light-emitting diodes, and quantum dot heterostructures. The challenge, however, lies in reducing the compositional grading effect of the constituent heterostructure materials across the interfaces in nanowires grown in vapor-liquid-solid mode.
Here, our previously developed nanowire growth technique called droplet-confined alternate pulsed-epitaxy [1] (an adaptation of conventional molecular beam epitaxy), which grants precise control over the axial growth rate and droplet composition, is employed to grow Al(x)Ga(1-x)As axial insertions in self-catalyzed GaAs nanowires. A full nanowire with six insertions is shown in Figure 1 (top). High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and nanowire growth models are utilized to gain an understanding of the compositional grading mechanism and its dependence on the growth temperature (TG), the nanowire radius (RNW), and the amount of supplied Al. Figure 1 (bottom) is an example HAADF-STEM image showing two atomically resolved Al(x)Ga(1-x)As insertions embedded in a zincblende GaAs nanowire, whereas Figure 2 shows the extracted Al-content (x) axial profiles for three selected insertions with different TG and RNW (the same amount of supplied Al). We show that lower TG and/or smaller RNW result in sharper interfaces, with a more profound improvement for the AlxGa1-xAs-to-GaAs interface. In the best case, almost symmetric insertions with interface thicknesses of only 2 – 3 monolayers are achieved, approaching the absolute limit of atomically sharp interfaces.
Thermodynamics, kinetics, and nanowire geometry are all factors considered during the formation of our Al(x)Ga(1-x)As insertions. Using two existing heterostructure growth models [2, 3] to fit our experimental data we can extract valuable quantitative information regarding the interface characteristics. Our results show for the first time that not only TG, but also size effects, i.e. a decreasing RNW, play a large role in the thermodynamic stability at the liquid-solid interface, setting previously unknown limitations on the maximum attainable interface sharpness. These findings and their implications will be discussed in detail.
The functionality of our insertions is successfully tested via their employment as axial barriers in quantum dot nanowire heterostructures. By growing the quantum dot heterostructure at 350 °C, consequently sharpening the quantum dot interfaces, we observe a one order of magnitude decrease in quantum dot emission linewidth (Figure 3) in comparison to a similar system grown at 550 °C.
1. Balaghi et al., Nano Lett. 16, 4032 (2016)
2. Luna et al., Phys. Rev. Lett. 109, 126101 (2012)
3. Priante et al., Nano Lett. 16, 1917 (2016)

Axial heterostructures have diverse functionality in electronic and optoelectronic devices. Implementing such systems in freestanding semiconducting nanowires further broadens the scope of potential applications, for example: distributed Bragg reflectors, high-efficiency light-emitting diodes, and quantum dot heterostructures. The challenge, however, lies in reducing the compositional grading effect of the constituent heterostructure materials across the interfaces in nanowires grown in vapor-liquid-solid mode.
Here, our previously developed nanowire growth technique called droplet-confined alternate pulsed-epitaxy [1] (an adaptation of conventional molecular beam epitaxy), which grants precise control over the axial growth rate and droplet composition, is employed to grow Al(x)Ga(1-x)As axial insertions in self-catalyzed GaAs nanowires. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and nanowire growth models are utilized to gain an understanding of the compositional grading mechanism and its dependence on the growth temperature (TG), the nanowire radius (RNW), and the amount of supplied Al. Figure 1 (a) is an example HAADF-STEM image showing two Al(x)Ga(1-x)As insertions embedded in a zincblende GaAs nanowire, whereas Figure 1 (b) shows the extracted Al-content (x) axial profiles for three selected insertions with different TG and RNW (the same amount of supplied Al). We show that lower TG and/or smaller RNW result in sharper interfaces, with a more profound improvement for the AlxGa1-xAs-to-GaAs interface. In the best case, almost symmetric insertions with interface thicknesses of only 2 – 3 monolayers are achieved, approaching the absolute limit of atomically sharp interfaces. The fitting of our experimental data with existing heterostructure growth models [2, 3] is suggestive of different mechanisms behind the compositional grading of the two interfaces and will be discussed in detail.
The functionality of our insertions is successfully tested via their employment as axial barriers in quantum dot nanowire heterostructures. By growing the quantum dot heterostructure at 350 °C, consequently sharpening the quantum dot interfaces, we observe a one order of magnitude decrease in quantum dot emission linewidth (Figure 1 (c)) in comparison to a similar system grown at 550 °C.
[1] Balaghi et al., Nano Lett. 16, 4032 (2016)
[2] Luna et al., Phys. Rev. Lett. 109, 126101 (2012)
[3] Priante et al., Nano Lett. 16, 1917 (2016)

Für diesen eingeladenen Vortrag zum Tokyo-Dresden NMR meeting: from quantum magnets to Weyl-Dirac fermions liegt keine Kurzfassung vor.

Für diesen eingeladenen Vortrag zur International Conference on Strongly Correlated Electron Systems (SCES) 2022 liegt keine Kurzfassung vor.

Für diesen Vortrag im Rahmen der zweiten EMFL summer school "Science in High Magnetic Fields" liegt keine Kurzfassung vor.

The organosilicon pyridine-2-olates 1a–1d (RSi(pyO)₃, R = Me (a), Ph (b), Bn (c), Allyl (d); pyO = pyridine-2-olate) may serve as tripodal ligands toward CuCl with formation of complexes of the type RSi(μ²-pyO)₃CuCl (2a–2d). In addition, for R = Allyl, formation of the more stable isomer 2d′ (κO-pyO)Si(μ²-pyO)₂(μ²-Allyl)CuCl was observed. In the presence of dry air (as a source of oxygen), reactions of 1a–1d and CuCl afforded Cu(II) complexes RSi(μ²-pyO)₄CuCl (3a–3d); 3a–3c in good yield, and 3d only as a side product. Reaction of Ph₂Si(pyO)₂ (4) and CuCl in equimolar ratio afforded, depending on reaction conditions, a series of (CuCl)n-ladder-type oligonuclear Cu(I) complexes Ph₂Si(μ2-pyO)₂(CuCl)n(μ²-pyO)₂SiPh₂ (n = 2 (52), 3 (53), 4 (54)). In all of the above compounds, the pyO group is Si–O bound and, in the case of μ² coordination, Cu–N bound. All new compounds (1c, 1d, 2b, 2c, 2d, 2d′, 3b, 3c, 3d, 52, 53, 54) were characterized by single-crystal X-ray diffraction, and further characterization includes solution ¹H, ¹³C, ²⁹Si NMR spectroscopy (1c, 1d, 2b, 2c, 2d’, 53, 54), solid-state ²⁹Si (2b, 2c, 2d′, 53, 54) and ⁶³Cu NMR spectroscopy (2c, 2d′) as well as computational analyses of the isomerization of the couple 2d, 2d′.

The use of accelerated electrons from a laser wakefield accelerator (LWFA) as drivers of a plasma wakefield stage (PWFA) provides compact PWFAs that can serve as a test bed for the efficient investigation and optimization of PWFAs and their development into brightness boosters. Such hybrid accelerators have been experimentally realized at HZDR and LMU to study novel injection schemes. To better understand the microscopic, nonlinear dynamic of these accelerators, the experiments were accompanied by 3D3V particle-in-cell simulations using PIConGPU.

Here, we present the latest results from these numerical studies, covering injections due to hydrodynamic shocks, beam self-modulation and breakup, and cavity elongation - all accompanied by synthetic diagnostic methods that allow direct comparison with experimental measurements.
Challenges such as parasitic injections, shock injections, and non-ideal driver beam dynamics will be discussed. Recent technical advances in PIConGPU that enabled the execution of these large-scale simulation campaigns are briefly covered, as well as new synthetic in situ shadowgraph and radiation diagnostics.

A review of the simulation work behind the recent LPWFA publications.

Understanding the physical and chemical properties of various materials demands detailed knowledge about their shape, structure, and composition. Particularly for nanoscale materials, characterization methods with high spatial and analytical resolution are required. Due to the small wavelength of strongly accelerated electrons, transmission electron microscopy (TEM) is one of the most appropriate nanoscale analysis techniques. Moreover, due to the tremendous range of signals arising from electron-solid interaction, a broad range of analysis modes are nowadays available in a transmission electron microscope.
After introducing the advantages of TEM, the basic setup of a transmission electron microscope, and the equipment available at HZDR for performing TEM analyses, the most important modes of imaging are presented, including bright-field, dark-field, and high-resolution imaging in TEM and scanning TEM (STEM) mode. It is shown, how diffraction analysis is used to derive structure and orientation information, while energy-dispersive X-ray spectroscopy (EDXS) and electron energy-loss spectroscopy (EELS) are applied for chemical composition analysis. Using examples from various research and application fields, including e.g. information technology, resource ecology, and radiopharmacy, the various TEM analysis modes are illustrated, and their combination is shown to be essential for a comprehensive understanding of nanoscale materials.

Dielectric capacitors are widely used in pulsed power electronic devices due to their ultrahigh power densities and extremely fast charge/discharge speed. To achieve enhanced energy storage density, maximum polarization (Pmax) and breakdown strength (Eb) need to be improved simultaneously. However, these two key parameters are inversely correlated. In this study, order–disorder transition induced polar nanoregions have been achieved in PbZrO3 thin films by making use of the low-energy ion implantation, enabling us to overcome the trade-off between high polarizability and breakdown strength, which leads to the tripling of the energy storage density from 20.5 to 62.3 J/cm3 as well as the great enhancement of breakdown strength. This approach could be extended to other dielectric oxides to improve the energy storage performance, providing a new pathway for tailoring the oxide functionalities.