Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Numerous natural substances have anti-cancer properties. Especially indigenous people use aqueous plant extracts for tea or ointments including Dioscorea sansibarensis Pax to treat various diseases. The aim of this study was to evaluate the cytotoxic and radiosensitizing potential of aqueous extracts from Dioscorea sansibarensis Pax collected from Kenya in a panel of HPV-negative and -positive head and neck squamous cell carcinoma (HNSCC) cells grown in three-dimensional laminin-rich extracellular matrix (3D lrECM). The results show cytotoxicity, radiosensitization and increased levels of residual double strand breaks (DBS) by Dioscorea sansibarensis Pax extracts in HPV-negative and -positive HNSCC models in a concentration- and cell model-dependent manner. Application of ROS scavengers indicated an association between ROS-induced DSB and radiosensitization through Dioscorea sansibarensis Pax pretreatment. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) based characterization of Dioscorea sansibarensis Pax identified the main components of the extract including camptothecin. Overall, Dioscorea sansibarensis Pax aqueous extracts alone and in combination with X-ray irradiation showed effective anticancer properties, which are worthy of further mechanistic investigation.

Pancreatic stellate cells (PSCs) in pancreatic adenocarcinoma (PDAC) are producing extracellular matrix, which promotes the formation of a dense fibrotic microenvironment. This makes PDAC a highly heterogeneous tumor-stroma driven entity, associated with reduced perfusion, limited oxygen supply, high interstitial fluid pressure, and limited bioavailability of therapeutic agents. In this study, spheroid and tumor xenograft co-culture models of human PSCs and PanC-1 cells were characterized radiopharmacologically using a combined positron emission tomography (PET) radiotracer approach. [18F]FDG, [18F]FMISO, and [18F]FAPI-74 were employed to monitor metabolic activity, hypoxic metabolic state, and functional expression of fibroblast activation protein alpha (FAPalpha), a marker of activated PSCs. In vitro, PanC-1 and co-culture spheroids demonstrated comparable glucose uptake and hypoxia, whereas FAPalpha expression was signifi-cantly higher in PSC spheroids. In vivo, glucose uptake as well as the transition to hypoxia was comparable in PanC-1 and co-culture xenograft models. In mice injected with PSCs FAPalpha ex-pression decreased over a period of four weeks post-injection, which was attributed to the suc-cessive death of PSCs. In contrast, FAPalpha expression increased in both PanC-1 and co-culture xenograft models over time due to invasion of mouse fibroblasts. The presented models are suitable for subsequently characterizing stromal cell-induced metabolic changes in tumors using noninvasive molecular imaging techniques.

The analysis of particle–bubble collisions in turbulent flow is a fundamental problem of high technological relevance, e.g., for the separation of valuable mineral particles by froth flotation. This relevance contrasts with an apparent lack of experimental data and understanding of this collision process. To this end, a periodic bubble chain was used to study the collision of millimeter-sized bubbles with polystyrene particles. The collision process between these entities was measured using 4D particle tracking velocimetry (PTV). By analyzing the collision data as a function of the polar angle along the bubble surface, we show that the collision took place not only at the leading edge but also at the trailing edge of the bubble. To understand the underlying mechanisms of the trailing edge collision, the flow field around a rising bubble chain was measured with Tomographic Particle Image Velocimetry (TPIV). The vortex formed in the bubble wake led to a velocity in the direction of the bubble surface that enabled trailing edge collisions. This effect is amplified by an increase in the turbulent kinetic energy and dissipation rate in the bubble wake. Overall, the investigation reveals different collision mechanisms and advances our understanding of the role of the wake in the bubble–particle collision.

Improvement in resolving hydrodynamic variables in multiphase flows is key to optimizing flotation performance. However, due to equipment complexity and opacity of three-phase systems, in situ measurements become challenging. Therefore, by using a novel multi-sensor approach, the aim of this study is to spatially resolve key hydrodynamic and gas dispersion parameters in a mechanical flotation cell such as superficial gas velocity (Jg), gas holdup (εg), bubble size distribution (BSD), and bubble surface area flux (Sb). A high-resolution inline endoscope (SOPAT), Jg and εg sensors were fixed at multiple axial positions in a 6L nextSTEP™ flotation cell. This multi-sensor concept has been applied to a simplified benchmark flotation scenario, as part of a binary (pyrite-quartz) flotation test campaign (30 % solid load). Varying operating conditions include tip speed (4.7 – 5.5 m/s), air flow (0.4 – 0.5 cm/s), frother (MIBC: 30 – 60 g/ton), and collector concentrations (PAX: 30 – 60 g/ton). Sb is a good indicator of gas dispersion efficiency in flotation, and local measurements indicated that there are significant differences in the local superficial gas velocities which can be measured with our adapted sensor. Real-time bubble size measurements reflected the high shear rates near the rotor–stator region. Overall, the gas flow rate and frother concentration were shown to have the most significant effect on the gas dispersion in the benchmark flotation tests.

Background and Purpose: To develop and test a decision tree for predicting contrast enhancement quality and shape using pre-contrast MRI sequences in a large adult-type diffuse glioma cohort.
Methods: Preoperative MRI scans (development/optimization/test sets: n=31/38/303, male=17/22/189, mean age=52/59/56.7 years, high-grade glioma=22/33/249) were retrospectively evaluated, including pre-and post-contrast T1-weighted, T2-weighted, fluid-attenuated inversion recovery, and diffusion-weighted imaging sequences. Enhancement prediction decision tree (EPDT) was developed using development and optimization sets, incorporating four imaging features: necrosis, diffusion restriction, T2 inhomogeneity, and nonenhancing tumor margins. EPDT accuracy was assessed on a test set by three raters of variable experience. True enhancement features (gold standard) were evaluated using pre- and post-contrast T1-weighted images. Statistical analysis used confusion matrices, Cohen’s/Fleiss’ kappa, and Kendall’s W. Significance threshold was P < 0.05.
Results: Raters 1, 2, and 3 achieved overall accuracies of 0.86 [95%-confidence interval (CI): 0.81-0.90], 0.89 (95%-CI: 0.85-0.92), and 0.92 (95%-CI: 0.89-0.95), respectively, in predicting enhancement quality (marked, mild, or no enhancement). Regarding shape, defined as the thickness of enhancing margin (solid, rim, or no enhancement), accuracies were 0.84 (95%-CI: 0.79-0.88), 0.88 (95%-CI: 0.84-0.92), and 0.89 (95%-CI: 0.85-0.92). Intra-rater inter-group agreement comparing predicted and true enhancement features consistently reached substantial levels [≥0.68 (95%-CI: 0.61-0.75). Inter-rater comparison showed at least moderate agreement (group: ≥0.42 (95%-CI: 0.36-0.48), pairwise: ≥0.61 (95%-CI: 0.50-0.72)]. Among the imaging features in the EPDT, necrosis assessment displayed the highest intra- and inter-rater consistency [≥0.80 (95%-CI: 0.73-0.88)].
Conclusion: The proposed enhancement prediction decision tree has high accuracy in predicting enhancement patterns of gliomas irrespective of rater experience.

Theory questions the persistence of non-reciprocal interactions in which one plant has a positive net effect on a neighbor that, in return, has a negative net impact on its benefactor—a phenomenon known as antagonistic facilitation. We develop a spatially explicit consumer-resource model for below-ground plant competition between ecosystem engineers, plants able to mine resources and make them available for any other plant in the community, and exploiters. We use the model to determine in what environmental conditions antagonistic facilitation via soil resource engineering emerges as an optimal strategy. Antagonistic facilitation emerges in stressful environments where ecosystem engineers’ self-benefits from mining resources outweigh the competition with opportunistic neighbors. Among all potential causes of stress considered in the model, the key environmental parameter driving changes in the interaction between plants is the proportion of the resource that becomes readily available for plant consumption in the absence of any mining activity. Our results align with theories of primary succession and the stress gradient hypothesis. However, we find that the total root biomass and its spatial allocation through the root system, often used to measure the sign of the interaction between plants, do not predict facilitation reliably.

Tetravalent actinides (An(IV)) widely occurs in the nuclear fuel cycle. For example, Pu(IV) and Th(IV) are the main species of these elements there, while U(IV) is also employed to reduce extractable Pu(IV) to unextractable Pu(III) in the PUREX process [1]. Therefore, the An(IV) chemistry needs to be understood in depth.
Previously, we have reported that An(IV) (An = Th, U, Np) commonly form sparingly soluble compounds with double-headed 2-pyrrolidone derivatives (L), (HL)2[An(NO3)6] (L = 14Cy and 12Cy, Fig. 1) in 3 M HNO3(aq) [2-3]. Based on these results, we have proposed an advanced principle for nuclear fuel reprocessing, namely NUuclear fuel MAterials selective Precipitation (NUMAP). In connection with this, we have preliminarily studied Ce(IV) as an inactive simulant of Pu(IV). However, Ce(IV) shows much different chemistry from that of An(IV), where [Ce2(μ-O)(NO3)6(14Cy)2]n including a [Ce-O-Ce]6+ motif is formed despite high acidic system with 3 M HNO3(aq) due to its strong hydrolysis tendency (Table 1) [4-5]. Up to now, Pu(IV) is known to exhibit both possibilities to form [Pu(NO3)6]2− and [Pu-O-Pu]6+ in crystal structures [6-7]. Therefore, we wonder which (HL)2[Pu(NO3)6] or [Pu2(μ-O)(NO3)6(L)2]n is preferred to be taken by Pu(IV) under presence of L in 3 M HNO3(aq). This makes critical difference in chemical stoichiometry of the Pu(IV) deposit for its recovery in the NUMAP reprocessing; the Pu:L mole ratio is 1:2 in (HL)2[Pu(NO3)6], while 1:1 in [Pu2(μ-O)(NO3)6(L)2]n. To answer this question, we have prepared Pu(IV)-nitrato complexes with L from HNO3(aq), and determined molecular and crystal structures of them as well as those of M(IV) analogues (M = Ce, Th, U).

Magnonics is a research field that has gained an increasing interest in both the fundamental and applied sciences in recent years. This field aims to explore and functionalize collective spin excitations in magnetically ordered materials for modern information technologies, sensing applications and advanced computational schemes. Spin waves, also known as magnons, carry spin angular momenta that allow for the transmission, storage and processing of information without moving charges. In integrated circuits, magnons enable on-chip data processing at ultrahigh frequencies without the Joule heating, which currently limits clock frequencies in conventional data processors to a few GHz. Recent developments in the field indicate that functional magnonic building blocks for in-memory computation, neural networks and Ising machines are within reach. At the same time, the miniaturization of magnonic circuits advances continuously as the synergy of materials science, electrical engineering and nanotechnology allows for novel on-chip excitation and detection schemes. Such circuits can already enable magnon wavelengths of 50 nm at microwave frequencies in a 5G frequency band. Research into non-charge-based technologies is urgently needed in view of the rapid growth of machine learning and artificial intelligence applications, which consume substantial energy when implemented on conventional data processing units. In its first part, the 2024 Magnonics Roadmap provides an update on the recent developments and achievements in the field of nano-magnonics while defining its future avenues and challenges. In its second part, the Roadmap addresses the rapidly growing research endeavors on hybrid structures and magnonics-enabled quantum engineering. We anticipate that these directions will continue to attract researchers to the field and, in addition to showcasing intriguing science, will enable unprecedented functionalities that enhance the efficiency of alternative information technologies and computational schemes.

In some locations around the globe, the U concentrations may exceed WHO standards by 2-folds therefore, effective yet environmentally wise solutions to purify radioactive waters are of significant importance. Here, the optimized and fully controlled coal-fly-ash based Na-P1 zeolite functionalization by employing novel, biodegradable biosurfactant molecule - cocamidopropyl betaine (CAPB) is showcased. The zeolite’s surface decoration renders three composites with varying amounts of introduced CAPB molecule (Na-P1 @ CAPB), with 0.44, 0.88, and 1.59-times External Cation Exchange Capacity (ECEC). Wet-chemistry experiments revealed extremely high U adsorption capacity (qmax = 137.1 mg U/g) unveiling preferential interactions of uranyl dimers with CAPB molecules coupled with ion-exchange between Na+ ions. Multimodal spectroscopic analyses, including FourierTransformed Infra-Red (FT-IR), X-ray Photoelectron (XPS), and X-ray Absorption Fine Structure (XAFS), showed the hexavalent oxidation state of U, and no secondary release of the CAPB molecule from the composite. The EXAFS signals fingerprint changes in the interatomic distances of adsorbed U, showing the impact of the O and N, heteroatoms present in the CAPB molecule on U binding mechanism. The presented research outcomes showcase the easy, scalable, optimized, and environmentally friendly synthesis of biofunctional zeolite effectively purifying the real-life U-bearing wastewaters from the vicinity of the Pribram deposit (Czech Republic).

The impulse of the Fourth Industrial Revolution is triggering the demand for few specific metals. These include copper, silver, gold, and platinum group metals (PGMs), with important applications in renewable energies, green hydrogen, and electronic products. However, the continuous extraction of these metals is leading to a rapid decline in their ore grades and, consequently, increasing the environmental impact of extraction. Hence, obtaining metals from secondary sources, such as waste electrical and electronic equipment (WEEE), becomes imperative for both environmental sustainability and ensuring availability. This recovery entails few problems such as allocation due to the simultaneous production of several metals, the use of non-renewable resources, and the exergy destruction during the life cycle of the metals. Therefore, this work analyses the waste printed circuit boards (PCBs) recycling process by proposing different exergy-based cost allocations for the mentioned metals, disaggregating the exergy cost into non-renewable and renewable, and considering the complete life cycle of metals with the Circular Thermoeconomics methodology. The results show a significant saving of non-renewable energy by using renewable energies in primary extraction (67-87%), recycling (97.6-98.5%), and renewable energies in recycling (98.7%, 99.0%), compared to conventional primary extraction. However, when considering the entire life cycle, between 47% and 53% of the non-renewable exergy is destroyed during recycling. Therefore, delaying recycling as much as possible would be the most desirable option for maximizing the use of non-renewable resources, which nature cannot replace in a short time.

Introduction The standard treatment for patients with focal drug-resistant epilepsy (DRE) who are not eligible for
open brain surgery is the continuation of anti-seizure medication (ASM) and neuromodulation. This treatment does not cure epilepsy but only decreases severity. The PRECISION trial offers a non-invasive, possibly curative intervention for these patients, which consist of a single stereotactic radiotherapy (SRT) treatment. Previous studies have shown promising results of SRT in this patient population. Nevertheless, this intervention is not yet available and reimbursed in the Netherlands. We hypothesize that: SRT is a superior treatment option compared to palliative standard of care, for patients with focal DRE, not eligible for open surgery, resulting in a higher reduction of seizure frequency (with 50% of the patients reaching a 75% seizure frequency reduction at 2 years follow-up).
Methods In this waitlist-controlled phase 3 clinical trial, participants are randomly assigned in a 1:1 ratio to either
receive SRT as the intervention, while the standard treatments consist of ASM continuation and neuromodulation.
After 2-year follow-up, patients randomized for the standard treatment (waitlist-control group) are offered SRT.
Patients aged ≥ 18 years with focal DRE and a pretreatment defined epileptogenic zone (EZ) not eligible for open
surgery will be included. The intervention is a LINAC-based single fraction (24 Gy) SRT treatment. The target volume is defined as the epileptogenic zone (EZ) on all (non) invasive examinations. The seizure frequency will be monitored on a daily basis using an electronic diary and an automatic seizure detection system during the night. Potential side effects are evaluated using advanced MRI, cognitive evaluation, Common Toxicity Criteria, and patient-reported outcome questionnaires. In addition, the cost-effectiveness of the SRT treatment will be evaluated.
Discussion This is the first randomized trial comparing SRT with standard of care in patients with DRE, non-eligible for open surgery. The primary objective is to determine whether SRT significantly reduces the seizure frequency 2 years after treatment. The results of this trial can influence the current clinical practice and medical cost reimbursement in the Netherlands for patients with focal DRE who are not eligible for open surgery, providing a non-invasive curative treatment option.

Purpose: Radio(chemo)therapy (RCT) as part of the standard treatment of glioma patients, inevitably leads to
radiation exposure of the tumor-surrounding normal-appearing (NA) tissues. The effect of radiotherapy on the
brain microstructure can be assessed by magnetic resonance imaging (MRI) using diffusion tensor imaging (DTI).
The aim of this study was to analyze regional DTI changes of white matter (WM) structures and to determine
their dose- and time-dependency.
Methods: As part of a longitudinal prospective clinical study (NCT02824731), MRI data of 23 glioma patients
treated with proton or photon beam therapy were acquired at three-monthly intervals until 36 months following
irradiation. Mean, radial and axial diffusivity (MD, RD, AD) as well as fractional anisotropy (FA) were investi-
gated in the NA tissue of 15 WM structures and their dependence on radiation dose, follow-up time and distance
to the clinical target volume (CTV) was analyzed in a multivariate linear regression model. Due to the small and
non-comparable patient numbers for proton and photon beam irradiation, a separate assessment of the findings
per treatment modality was not performed.
Results: Four WM structures (i.e., internal capsule, corona radiata, posterior thalamic radiation, and superior
longitudinal fasciculus) showed statistically significantly decreased RD and MD after RT, whereas AD decrease
and FA increase occurred less frequently. The posterior thalamic radiation showed the most pronounced changes
after RCT [i.e., ΔRD = −8.51 % (p = 0.012), ΔMD = −6.14 % (p = 0.012)]. The DTI changes depended
significantly on mean dose and time.
Conclusion: Significant changes in DTI for WM substructures were found even at low radiation doses. These
findings may prompt new radiation dose constraints sparing the vulnerable structures from damage and sub-
sequent side-effects.

Personalized treatment strategies based on non‑invasive biomarkers have potential to improve
patient management in patients with newly diagnosed glioblastoma (GBM). The residual tumour
burden after surgery in GBM patients is a prognostic imaging biomarker. However, in clinical patient
management, its assessment is a manual and time‑consuming process that is at risk of inter‑rater
variability. Furthermore, the prediction of patient outcome prior to radiotherapy may identify
patient subgroups that could benefit from escalated radiotherapy doses. Therefore, in this study,
we investigate the capabilities of traditional radiomics and 3D convolutional neural networks for
automatic detection of the residual tumour status and to prognosticate time‑to‑recurrence (TTR)
and overall survival (OS) in GBM using postoperative [11C] methionine positron emission tomography
(MET‑PET) and gadolinium‑enhanced T1‑w magnetic resonance imaging (MRI). On the independent
test data, the 3D‑DenseNet model based on MET‑PET achieved the best performance for residual
tumour detection, while the logistic regression model with conventional radiomics features performed
best for T1c‑w MRI (AUC: MET‑PET 0.95, T1c‑w MRI 0.78). For the prognosis of TTR and OS, the
3D‑DenseNet model based on MET‑PET integrated with age and MGMT status achieved the best
performance (Concordance‑Index: TTR 0.68, OS 0.65). In conclusion, we showed that both deep‑
learning and conventional radiomics have potential value for supporting image‑based assessment
and prognosis in GBM. After prospective validation, these models may be considered for treatment
personalization.

Objective In the era of image-guided adaptive radiotherapy, definition of the clinical target volume (CTV) is a challenge in various solid tumors, including esophageal cancer (EC). Many tumor microenvironmental factors, e.g., tumor cell proliferation or cancer stem cells, are hypothesized to be involved in microscopic tumor extension (MTE). Therefore, this study assessed the expression of FAK, ILK, CD44, HIF-1α, and Ki67 in EC patients after neoadjuvant radiochemotherapy followed by tumor resection (NRCHT+R) and correlated these markers with the MTE.
Methods Formalin-fixed paraffin-embedded tumor resection specimens of ten EC patients were analyzed using multiplex immunofluorescence staining. Since gold fiducial markers had been endoscopically implanted at the proximal and distal tumor borders prior to NRCHT+R, correlation of the markers with the MTE was feasible.
Results In tumor resection specimens of EC patients, the overall percentages of FAK+, CD44+, HIF-1α+, and Ki67+ cells were higher in tumor nests than in the tumor stroma, with the outcome for Ki67+ cells reaching statistical significance (p< 0.001). Conversely, expression of ILK+ cells was higher in tumor stroma, albeit not statistically significantly. In three patients, MTE beyond the fiducial markers was found, reaching up to 31mm.
Conclusion Our findings indicate that the overall expression of FAK, HIF-1α, Ki67, and CD44 was higher in tumor nests, whereas that of ILK was higher in tumor stroma. Differences in the TME between patients with residual tumor cells in the original CTV compared to those without were not found. Thus, there is insufficient evidence that the TME influences the required CTV margin on an individual patient basis.

The evidence for the value of particle therapy (PT) is still sparse. While randomized trials remain a cornerstone for robust comparisons with photon-based radiotherapy, data registries collecting real-world data can play a crucial role in building evidence for new developments. This Perspective describes how the European Particle Therapy Network (EPTN) is actively working on establishing a prospective data registry encompassing all patients undergoing PT in European centers. Several obstacles and hurdles are discussed, for instance harmonization of nomenclature and structure of technical and dosimetric data and data protection issues. A preferred approach is the adoption of a federated data registry model with transparent and agile governance to meet European requirements for data protection, transfer, and processing. Funding of the registry, especially for operation after the initial setup process, remains a major challenge.

The Puga valley, in Ladakh, contains one of India’s most prospective geothermal systems. Substantial geophysical and geochemical research has been conducted to characterise this system, though uncertainties regarding the subsurface reservoir’s geometry and permeability structure remain a barrier to its development. In this contribution, we aim to fill some of these knowledge gaps by integrating new geological data and structural analyses with previously published geochemical and geophysical interpretations, and derive an integrated conceptual model of the geothermal system. Using digital outcrop techniques and field mapping, we identify and characterise several important structures (faults and foliations) that facilitate fluid flow in the otherwise impermeable Tso Morari gneiss. Petrological and field evidence for outcropping hydrothermally altered lithologies, that may have formed in a geothermal system analogous to the active one, are also presented. Based on these observations, and a simplified finite-element model, we suggest that tectonic and topographic stresses likely control reservoir architecture and connectivity. Lastly, we caution that geomorphological evidence for neotectonic movement on faults at Puga indicate the need for seismic hazard assessment prior to exploitation of the geothermal system, and identify potential parallels between Puga and the Yangbajing geothermal field in China.

Antiferromagnetic materials have unique properties due to their alternating spin arrangements. Their compensated magnetic order, robust against external magnetic fields, prevents long-distance crosstalk from stray fields. Furthermore, antiferromagnets with combined parity and time-reversal symmetry enable electrical control and detection of ultrafast exchange-field enhanced spin manipulation up to THz frequencies. Here we report the experimental realization of a nonvolatile antiferromagnetic memory mimicking an artificial synapse, in which the reconfigurable synaptic weight is encoded in the ratio between reversed antiferromagnetic domains. The non-volatile memory is “written” by spin-orbit torque-driven antiferromagnetic domain wall motion and “read” by nonlinear magnetotransport. We show that the absence of long-range interacting stray magnetic fields leads to very reproducible electrical pulse-driven variations of the synaptic weights.

The present work reports a systematic study of the potential degradation of metals and dielectric thin films in different space environments. The mono- and bilayers selected are made of materials commonly used for the realization of optical components, such as reflective mirrors or building blocks of interferential filters. More than 400 samples were fabricated and irradiated with protons at different energies on ground-based facilities. The fluences were selected as a result of simulations of the doses delivered within a long-term space mission considering different orbits (Sun close, Jovian, and Geostationary orbits). In order to stress the samples at different depths and layer interfaces, experiments were carried out with a range of proton energies within 1 and 10 MeV values. An estimate of a safe maximum fluence has been provided for each type of sample at each energy. The damage mechanism, when present, has been investigated with different optical and structural techniques.

Electric power systems during transient states are extensively investigated using variations of the Kuramoto model to analyze their dynamic behavior. However, the majority of current models fail to capture the physics of power flows and the heterogeneity of the grids under study. This study addresses this gap by comparing the levels of heterogeneity in continent-sized power grids in Europe and North America to reveal the underlying universality and heterogeneity of grid frequencies, electrical parameters, and topological structures. Empirical data analysis of grid frequencies from the Hungarian grid indicates that q-Gaussian distributions best fit simulations, with spatio-temporally correlated noise evident in the frequency spectrum. Comparing European and North American power grids reveals that employing homogeneous transmission capacities to represent power lines can lead to misleading results on stability, and nodal behavior is heterogeneous. Community structures of the continent-sized grids are detected, demonstrating that Chimera states are more likely to occur when studying only subsystems. A topographical analysis of the grids is presented to assist in selecting such subsystems. Finally, synchronization calculations are provided to illustrate the occurrence of Chimera states. The findings underscore the necessity of heterogeneous grid models for dynamic stability analysis of power systems.

The application of shape memory materials is based on a reversible martensitic transformation, which changes structure and microstructure. All applications like high stroke actuation, sensing, energy-efficient ferroic cooling, and energy harvesting, benefit from a high cycle frequency, as this allows for high power density. For this, thin films are of particular interest as their high surface-to-volume ratio enables fast heating and cooling. However, up to now the influence of fast heating and cooling on the martensitic microstructure is unknown. Here we examine the influence of flash lamp annealing on epitaxial Ni-Mn-Ga films. Single-crystalline films are suitable as a model system since they allow for an undisturbed, well-ordered hierarchical martensitic microstructure after slow cooling. We examine all levels of this twin-within-twins microstructure by a combination of XRD, (FIB-) SEM and FIB-TEM before and after flash lamp annealing with a duration of 3 ms at different energy densities. We observe substantial changes at all levels of twinning, which we attribute to the finite time available to form a hierarchical microstructure and the thermal stress between film and substrate.

Shape memory alloys have a wide range of applications, including high stroke actuation, energy-efficient ferroic cooling, and energy harvesting. The use of these alloys is based on a reversible martensitic transformation, which leads to a complex microstructure in the martensitic state. Understanding the formation of this microstructure after fast heating and cooling is crucial, since all above mentioned applications benefit from a high cycle frequency, as it allows a high power density. Here, to study the formation of the martensitic microstructure after fast heating and cooling, we use epitaxial Ni-Mn-Ga film as a model system, since the high surface-to-volume ratio of thin films enables rapid heating and cooling. Furthermore, the formation of a multi-level hierarchical microstructure after slow cooling of this material system is well understood. We apply a millisecond flash lamp pulse on Ni-Mn-Ga films and analyse the hierarchical martensitic microstructure after the flash lamp pulse at different energy densities. We observe substantial changes compared to slow cooling, which we attribute to the limited time available for the microstructure to form and to the thermal stress between film and substrate during rapid temperature changes.

The magnetic damping of Ni80Fe20 (Permalloy, Py) thin films is studied via frequency-dependent ferromagnetic resonance (FMR) experiments. The thickness of the Py films is kept constant and they are all protected from oxidation by an identical 5-nm-thick Al cap layer. To separate the Py film from the oxidic sapphire substrates a systematic variation of the thickness of an additional Al spacer layer was carried out. Py sandwiched in Al exhibits a low, purely Gilbert-like magnetic damping when the Al spacer layer thickness is kept below 3 nm. Above this thickness the magnetic damping is strongly increased due to a pronounced two-magnon contribution. A detailed investigation of the temperature dependence as well as full angular dependence of the FMR allows for correlating the magnetic properties of the Py with the microscopic structural properties of the films as studied by x-ray reflectivity and transmission electron microscopy. It turns out that the detrimental twomagnon processes are activated by an island-like growth of the Al spacer layers, which leads to rough, wavy interfaces with characteristic length scales of the order of ten nanometers. Nevertheless, for Al spacer layers with a thickness below 3 nm a low, purely Gilbert-like magnetic damping can be observed.

Time-dependent density functional theory (TDDFT) is a widely used method to investigate electron dynamics under various external perturbations such as laser fields. In this work, we present a novel approach to accelerate real time TDDFT based electron dynamics simulations using autoregressive neural operators as time-propagators for the electron density. By leveraging physics-informed constraints and high-resolution training data, our model achieves superior accuracy and computational speed compared to traditional numerical solvers. We demonstrate the effectiveness of our model on a class of one-dimensional diatomic molecules. This method has potential in enabling real-time, on-the-fly modeling of laser-irradiated molecules and materials with varying experimental parameters.

Ternary nitrides are rapidly emerging as promising compounds for optoelectronic and energy conversion applications, yet comparatively little of this vast composition space has been explored. Furthermore, the crystal structures of these compounds can exhibit a significant amount of disorder, the consequences of which are not yet well understood. Here, the deposition of bixbyite-type ZrTaN3 thin films is demonstrated by reactive magnetron co-sputtering and observed semiconducting character, with a strong optical absorption onset at 1.8 eV and significant photoactivity, with prospective application as functional photoanodes. It is found that Wyckoff-site occupancy of cations is a critical factor in determining these beneficial optoelectronic properties. First-principles calculations show that cation disorder leads to minor deviations in the total energy but modulates the bandgap by 0.5 eV, changing orbital hybridization of valence and conduction band states. In addition to demonstrating that ZrTaN3 is a promising visible light-absorbing semiconductor and active photoanode material, the findings provide important insights regarding the role of cation ordering on the electronic structure of ternary semiconductors. In particular, it is shown that not only cation order, but also the cationic Wyckoff site occupancy has a substantial impact on key optoelectronic properties, which can guide future design and synthesis of advanced semiconductors.

In today's era of digitalization, managing the lifecycle of research projects demands efficient navigation through a myriad of data sources and services. This presentation delves into the pivotal role of HELIPORT, a web browser-based guidance system, in streamlining research project lifecycle management. HELIPORT serves as a comprehensive platform, seamlessly connecting disparate services and systems to facilitate the smooth flow of digital data throughout the entire research process. By harnessing HELIPORT's capabilities, researchers can effectively track, organise, and share data and workflows with colleagues, thereby enhancing collaboration. The embedding of computational workflows to automate processes and provide comprehensible and reproducable workloads on HPC clusters is an essential part of this process. In the talk, we explore how HELIPORT is expanding the digital horizon and empowering researchers to push new boundaries in scientific exploration.

Various concepts for the final disposal of spent nuclear fuel are under discussion. In addition to the direct disposal of spent fuel, there are reprocessing concepts in which separated spent fuel components such as fission products and actinides require a suitable host matrix. Options for the immobilization of specific radionuclides are vitrification into a glass material or embedding into a ceramic matrix [1]. We have examined various ceramic materials (zirconia, (ZrO2 and YSZ), zircon (ZrSiO4), monazite (LaPO4) and pyrochlore (Gd2Zr2O7)) with regard to their suitability as host materials for actinides and lanthanides. Th(IV), U(IV), Eu(III) and Ce(IV) were incorpo-rated into the host lattices. The host material must fulfill various requirements. (1) There must be a sufficiently high solubility of actinides and lanthanides in the host lattice without causing phase separation. (2) The host material must have a high temperature stability (up to 1200K) without phase transitions, as this could result in mechanical stresses and fractures which may re-duce the resistance to leaching. (3) The material must be able to withstand the pressure in the ge-ological formation and also the pressure that can be generated by He gas due to alpha decay (up to 10 GPa). (4) The structure of the host lattice must be able to withstand the recoil effects of al-pha decay. Systematic investigations of these aspects were carried out in the frame of an inter-disciplinary project by using synchrotron diffraction techniques available at the Rossendorf Beamline (ROBL) at ESRF. The following is an overview of the main results.
ZrO2 with low dopant concentrations shows a phase transition from the monoclinic (m-ZrO2) to the tetragonal (t-ZrO2) phase both at elevated temperatures and upon irradiation, which characterize it as less suitable as a host material. If the t-ZrO2 and the cubic (c-ZrO2) phases are stabilized for ambient conditions, e.g. by doping with yttrium (YSZ) [2], the ceramic becomes resistant in presence of Th(IV) to high temperature and pressure [3]. The structure also maintains its integrity under irradiation [4]. Synthetic monazite shows remarkable amorphization of the structure under irradiation [5], but has the tendency to recrystallize easily [6]. This is also ob-served in U(IV) and Th(IV) containing natural monazites. A solid solution of Th(IV) pyrochlore results in the formation of Gd2-xThxZr2O7+x/2. Th(IV) replaces Gd(III) due to the similar ionic ra-dius and thus requires charge compensation. The pyrochlore structure retains its integrity under high temperature and pressure conditions [7]. Zircon, ZrSiO4, with incorporated Th(IV), shows excellent stability at high pressure and temperature [8]. However, the synthesis is complicated because a phase separation of (Th,Zr)SiO4 and ThO2 easily occurs.
Based on these studies we can classify the suitability of these ceramics as host materials. We have further developed diffraction techniques for the targeted analysis under the above mentioned conditions. This project is fully supported by BMBF grant 02NUK060 (AcE).
[1] R. C. Ewing, W. J. Weber, F. W. Clinard, Progress in Nuclear Energy 29, 63-127 (1995).
[2] V. Svitlyk, S. Weiss, S., C. Hennig, J Am Ceram Soc. 105, 5975-5983 (2022).
[3] V. Svitlyk, S. Weiss, S., C. Hennig, J Am Ceram Soc. 105, 7831-7839 (2022).
[4] V. Svitlyk, L. Braga Ferreira dos Santos, J. Niessen, S. Gilson, J. Marquardt, S. Findeisen, S. Richter, S. Akhmadaliev, N. Huittinen, C. Hennig, J. Synchrotron Rad. 31, 355-362 (2004).
[5] S. E. Gilson, V. Svitlyk, A. A. Bukaemskiy, J. Niessen, T. Lender, G. L. Murphy, M. Henkes, H. Lippold, J. Marquardt, S. Akhmadaliev, C. Hennig, B. Winkler, T. Tonnesen, L. Peters, C. Fischer, N. Huittinen, npj Mat. Degr. Submitted.
[6] T. Lender, G. Murphy, E. Bazarkina, A. Bukaemskiy, S. Gilson,M. Henkes, C. Hennig, A. Kaspor, M. Klinkenberg, K. Kvashnina, J. Marquardt, J. Nießen, L. Peters, J. Poonoosamy, A. Rossberg, V. Svitlyk, N. Huittinen, npj Mat. Degr. Submit-ted.
[7] V. Svitlyk, S. Weiss, G. Garbarino, R. Huebner, A. Worbs, N. Huittinen, C. Hennig, Z. Krist. In press.
[8] V. Svitlyk, S. Weiss, G. Garbarino, S. Shams Aldin Azzam, R. Huebner, A. Worbs, N. Huittinen, C. Hennig, Acta Materi-alia, Submitted.

Electrochemical cells employing Sodium (Na) and Zinc (Zn) electrodes and a chloride salt electrolyte have been imaged by neutron radiography during cycling. The use of such abundant raw materials confers a very low energy-normalised cost to the Na-Zn system, but its operation requires them to be entirely molten, and therefore to be operated at 600 °C. To suppress the self-discharge that results from this all-molten configuration, porous ceramic diaphragms are used to partition the electrolyte and thereby impede the movement of the Zn2+ ions responsible towards the Na electrode. Neutron images reveal large gas bubbles trapped beneath these diaphragms, formed during the cell fabrication process due to the large volume change that accompanies melting/solidifying of the electrolyte. Cycling data confirm that these bubbles interfere with cell operation by substantially increasing ohmic resistance. They indicate the need for either a new diaphragm design, or a cell fabrication process that prevents their formation in the first instance.

This repository entails the data and Pythoncode for the publication "Dynamics of Lagrangian Sensor Particles: The Effect of Non-Homogeneous Mass Distribution" in the journal "Processes".

In the following a brief introduction and guide based on the folders in the repository is laid out. More code specific instructions can be found in the respective codes.

01 --> The tracking always begins with the same 01_milti[...] folder in which the python code with OpenCV algorithm is located. For tracking the tracking to work certain directories are required in which the raw images are to be stored (separate from anything else) as well as a directory in which the results are to be save (not the same directory as the raw data).

After tracking is completed for all respective experiments and the results directories are adequately labelled and stored any of the other code files can be used for respective analyses. The order of folders beyond the first 01 directory has no relevance to the order of evaluation however can ease the understanding of evaluated data if followed.

02 --> Evaluation of amount of circulations and respective circulation time in experimental vat. (code can be extended to calculate the circulation time based on the various plains that are artificially set)

03 --> Code for the calculation of the amount of contacts with the vat floor. Code requires certain visual evaluations based on the LP trajectories, as the plain/barrier for the contact evaluation has to be manually set.

04 --> Contains two codes that can be applied to results data to combine individual results into larger more processable arrays within python

05 --> Contains the code to plot the trajectory of single experiments of Lagrangian particles based on their positional results and velocity at respective position, highlighting the trajectory over the experiment.

06 --> Condes to create 1D histograms based on the probability density distribution and velocity distributions in cumulative experiments.

07 --> Codes for plotting the 2D probability density distribution (2D Histograms) of Lagrangian Particles based on the cumulative experiments. Code provides values for the 2D grid, plotting is conducted in Origin Lab or similar graphing tools, graphing can also be conducted in python whereby the seaborn (matplotlib) library is suggested.

08 --> Contain the code for the dimensionless evaluation of the results based on the respective Stokes number approaches and weighted averages. 2D histograms are also vital to this evaluation, whereby the plotting is again conducted in Origin Lab as values are only calculated in code.

09 --> Directory does not contain any python codes but instead contains the respective Origin Lab files for the graphing, plotting and evaluation of results calculated via python is given. Respective tables, histograms and heat maps are hereby given to be used as templates if necessary.

The project used the Origin 2023 (64-bit) version, if no Origin license is available then Origin Lab provides a free Origin Viewer with which the projects can be opened and viewed. (https://www.originlab.com/viewer/)

Glutamine (Gln) is a nonessential amino acid that is involved in the development and progression of several malignancies, including prostate cancer (PCa). While Gln is nonessential for normal prostate epithelial cells, PCa cells become highly dependent on an exogenous source of Gln. The Gln metabolism in PCa is tightly controlled by well-described oncogenes such as MYC, AR, and mTOR. These oncogenes contribute to therapy resistance and progression to the aggressive castration-resistant PCa. Inhibition of Gln catabolism impedes PCa growth, survival, and tumor-initiating potential while sensitizing the cells to radiotherapy. Therefore, given its significant role in tumor growth, targeting Gln metabolism is promising for developing new therapeutic strategies. Ongoing clinical trials evaluate the safety and efficacy of Gln catabolism inhibitors in combination with conventional and targeted therapies in patients with various solid tumors, including PCa. Therefore, understanding how tumor cells interact with their microenvironment will facilitate the clinical translation of Gln inhibitors and help improve therapeutic outcomes. This review focuses on the respective roles of Gln in PCa progression and therapy resistance and provides insights into current clinical trials.

This paper shown that millisecond annealing effectively suppresses the B diffusion in Germanium after ion implantation, and provides much higher activation efficiency of acceptors compared to conventional annealing methods.

The diameter distribution of bubbles in foam is one of the most important features in foam-based separation processes like foam fractionation and froth flotation. In this study the bubble size at different radial positions of pneumatically produced foams without coalescence and coarsening of bubbles is investigated in a cylindrical column by employing an invasive sampling probe. It is shown that pronounced differences of the local Sauter-mean diameter of the bubbles can appear in radial direction. Oftentimes a parabolic profile with the largest mean bubble diameter in the center of the column is found. The difference of the Sauter-mean diameter between wall- and center region is in the order of up to 60%. Experiments on foams produced with different spargers, gas flow rates and liquid filling levels reveal that the actual degree of the inhomogeniety depends on the specific bubble size distribution that is produced by the sparger, and becomes more pronounced if the range of bubble diameters in the foam increases. As an explanation for the observations, hydrodynamic interactions in the liquid phase, as well as the behavior of different sized bubbles close to the liquid/foam interface are proposed. The observed existence of local differences of the bubble diameters can have a strong influence the dynamic behavior, like liquid drainage, and measurement methods of pneumatic foams. In particular it can limit the applicability of surface-based bubble size measurements.

Bubble column reactor consisting of a vertical vessel filled with liquid and a gas distributor belongs to the widely-used multiphase reactors. Despite the simple arrangement, the hydrodynamics of bubble columns is very complex due to the interaction and exchange between liquid and gas phases. The mechanism of interphase interaction is affected largely by the flow regime prevailing in the reactor, which may vary from homogeneous-bubbly flow regime, via slug, churn-heterogeneous to annular flow regime. In the homogeneous regime, the interaction between bubbles as well as coalescence and breakup is negligible, which provides well-defined conditions for the investigation of the momentum and turbulence transfer between the bubbles and the liquid. This study discusses the effects of surfactants based on experimental investigations and Computational Fluid Dynamics (CFD) simulations of a homogeneous bubble column, where the bubbles are injected from the column bottom through multiple uniformly distributed orifices.

In this lecture I will show how neural networks can be used to solve differential equations. We will consider the basic example of the quantum harmonic oscillator. After reviewing some basic concepts, we will implement two machine learning methods to solve the time-dependent Schrödinger equation for the harmonic oscillator. First, we will consider a data-driven approach where a fully connected neural network is used to learn the solutions of the differential equation based on input labels. In the second approach, we will consider physics-informed neural networks. In contrast to the data-driven approach, the solution of the differential equation is not learned by mapping input features to outputs, but by minimizing a loss term related to the form of the differential equation. The lecture will be both formal and interactive using Jupyter notebooks.

In this lecture I will introduce the concept of neural networks. We will begin with a brief overview of the development of artificial neural networks. We will look at the basic perceptron model from a mathematical point of view and implement it to solve a simple classification problem. In the last part of the lecture, I will provide a gentle interactive introduction to deep learning using a simple toy problem about digital colors. We will learn how to build neural network pipelines and develop a qualitative understanding. The lecture will be both formal and interactive using Jupyter notebooks.

Semiconducting ternary nitrides are a promising class of materials that have received increasing attention in recent years, but often show high free electron concentrations due to the low defect formation energies of nitrogen vacancies and substitutional oxygen, leading to degenerate n-type doping. To achieve non-degenerate behavior, we now investigate a family of amorphous calcium–zinc nitride (Ca–Zn–N) thin films. By adjusting the metal cation ratios in the films, we demonstrate band gap tunability between 1.4 and 2.0 eV and control over the charge carrier concentration across six orders of magnitude, all while maintaining high mobilities between 5 and 70 cm²/(Vs). The combination of favorable electronic properties, low synthesis temperatures, and earth-abundant elements makes amorphous calcium zinc nitride highly promising for future sustainable electronics. Moreover, the successful synthesis of such materials, as well as their broad optical and electrical tunability, paves the way for a new class of tailored functional materials: amorphous nitride semiconductors – ANSs.

Here we report the synthesis of the 6-(6-methyl-1,2,4,5-tetrazine-3-yl)-2,2‘-bipyridine (MTB) ligand, that has been developed for lanthanide/actinide separation. A multi-method study of the
complexation of MTB with trivalent actinide and lanthanide ions is presented. Single crystal X-ray diffraction measurements reveal the formation of [Ce(MTB)2(NO3)3], [Pr(MTB)NO3)3H2O], and [Ln(MTB)(NO3)3MeCN] (Ln = Nd, Sm, Eu, Gd). In addition, the complexation of Cm(III) with MTB in solution was studied by time-resolved laser fluorescence spectroscopy. The results show the formation of [Cm(MTB)1-3] 3+ complexes, which occurs in two different isomers. Quantum chemical calculations reveal an energy difference between these isomers of 12 kJ mol-1, clarifying the initial observations made by TRLFS. Furthermore, QTAIM analysis of the Cm(III) and Ln(III) complexes was performed, indicating a stronger covalent contribution in the Cm-N interaction compared to the respective Ln-N interaction. These findings align well with extraction data showing a preferred extraction of Am and Cm over lanthanides (e.g., max. SFAm/Eu = 8.3) at nitric acid concentrations < 0.1 mol L-1 HNO3.
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Planar Hall magnetoresistive sensors (PHMR) are promising candidates for various magnetic sensing applications due to their high sensitivity, low power consumption, and compatibility with integrated circuit technology. However, their performance is often limited by inherent noise sources, impacting their resolution and overall sensitivity. Here the effect of three bilayer structures NiFe(10 nm)/IrMn(10 nm), NiFe(30 nm)/IrMn(10 nm), and NiFe(30 nm)/IrMn(20 nm) on noise levels is investigated at low-frequency (DC - 100 Hz). This study includes a detailed investigation on the optimization process and noise characteristics of multiring PHMR sensors, focusing on identifying and quantifying the dominant noise sources. The experimental measurements are complemented by a theoretical analysis of noise sources including thermal noise, 1/f noise, intermixing and environmental noise. The best magnetic resolution is observed for the NiFe(30 nm)/IrMn(10 nm) structure, which achieves a detectivity below 1.5 nT/√Hz at 10 Hz in a harsh environment at room temperature. In addition, a substantial improvement in sensitivity is observed by annealing the sensors at 250 °C for 1 hour. The findings of this study contribute to a deeper understanding of noise behavior in PHMR sensors, paving the way for developing strategies to improve their performance for demanding sensing applications at low frequencies.

I will talk about two recent efforts to apply advanced machine learning methods to the electronic structure problem at the density functional theory (DFT) level. First, I will present a machine learning approach based on physics-informed neural networks and neural operators for inverting the Kohn-Sham equations for the exchange-correlation (XC) potential; neural networks provide a new way to perform DFT inversions at scale by learning the mapping from density to potential [1]. Second, I will present a very recent development in which we use neural operators to predict the electron dynamics of systems driven by a laser field. This approach complements conventional numerical solvers and has the potential to enable real-time, on-the-fly modeling of laser-irradiated molecules and materials with varying experimental parameters [2]. Both methods are illustrated on a conceptual level using one-dimensional models of diatomic molecules, but the approach can be readily applied to realistic systems in three dimensions.

[1] V. Martinetto, K. Shah, A. Cangi, A. Pribram-Jones, Mach. Learn.: Sci. Technol. 5, 015050 (2024).
[2] K. Shah, P. Stiller, N. Hoffmann, A. Cangi, arXiv:2210.12522 (2022).

I will present our recent progress in significantly scaling up density functional theory calculations with machine learning [1], for which we have developed the Materials Learning Algorithms (MALA) framework [2]. We have demonstrated the transferability of our machine learning model across phase boundaries, such as metals at their melting point [3] and electronic temperature [4]. In addition, our use of automated machine learning has led to a significant reduction in the computational resources required to identify optimal neural network architectures [5]. Most importantly, I will present our recent breakthrough in enabling fast neural-network driven electronic structure calculations for ultra-large systems unattainable by conventional density functional theory calculations [6]. I will mention in passing our other efforts in solving the Kohn-Sham equations of time-dependent density functional theory in terms of physics-informed neural networks [7], and in developing a robust framework for inverting the Kohn-Sham equations in terms of Fourier neural operators [8].

[1] L. Fiedler, K. Shah, M. Bussmann, A. Cangi, Phys. Rev. Materials, 6, 040301 (2022).
[2] A. Cangi, S. Rajamanickam, B. Brzoza, T. J. Callow, J. A. Ellis, O. Faruk, L. Fiedler, J. Fox, N. Hoffmann, K. D. Miller, D. Kotik, S. Kulkarni, N. Modine, P. Mohammed, V. Oles, G. A. Popoola, F. Pöschel, J. Romero, S. Schmerler, J. A. Stephens, H. Tahmasbi, A. P. Thompson, S. Verma, D. J. Vogel, Materials Learning Algorithms (MALA), doi.org/10.5281/zenodo.5557254, (2023).
[3] J. Ellis, L. Fiedler, G. Popoola, N. Modine, J. Stephens, A. Thompson, A. Cangi, S. Rajamanickam, Phys. Rev. B, 104, 035120 (2021).
[4] L. Fiedler, N. A. Modine, K. D. Miller, A. Cangi, Phys. Rev. B 108, 125146 (2023).
[5] L. Fiedler, N. Hoffmann, P. Mohammed, G. Popoola, T. Yovell, V. Oles, J. Austin Ellis, S. Rajamanickam, A. Cangi, Mach. Learn.: Sci. Technol., 3, 045008 (2022).
[6] L. Fiedler, N. Modine, S. Schmerler, D. Vogel, G. Popoola, A. Thompson, S. Rajamanickam, A. Cangi, npj. Comput. Mater., 9, 115 (2023).
[7] K. Shah, P. Stiller, N. Hoffmann, A. Cangi, Physics-Informed Neural Networks as Solvers for the Time-Dependent Schrödinger Equation, NeurIPS Workshop Machine Learning and the Physical Sciences, arXiv:2210.12522 (2022).
[8] V. Martinetto, K. Shah, A. Cangi, A. Pribram-Jones, Inverting the Kohn-Sham equations with physics-informed machine learning, arXiv:2312.15301 (2023).

We study numerically the flow around a spherical droplet set fixed in a linear shear flow over a wide range of external Reynolds numbers ($0.1<\Rey\leq250$, $\Rey$ based on the slip velocity and the viscosity of the external fluid) and drop-to-fluid viscosity ratios ($0.01\leq\mu^\ast\leq100$). The flow structure, the vorticity field, and their intrinsic connection with the lift force are analysed. Specifically, the results on lift force are compared with the low-$\Rey$ solution derived for droplets of arbitrary $\mu^\ast$, as well as prior data at finite $\Rey$ available in both the clean-bubble limit ($\mu^\ast\to0$) and the solid-sphere limit ($\mu^\ast\to\infty$). Notably, at moderately high Reynolds numbers, $\Rey=O(100)$, the lift force exhibits a non-monotonous transition from $\mu^\ast\to0$ to $\mu^\ast\to\infty$, peaking at approximately $\mu^\ast\approx1$. This behavior is related to an internal 3D flow \textcolor{blue}{bifurcation} also occurring under uniform-flow conditions, which makes the flow to evolve from axisymmetric to biplanar symmetric. This flow \textcolor{blue}{bifurcation} occurs at low-but-finite $\mu^\ast$ when the internal Reynolds number ($\Rey^i$, based on the viscosity of the internal fluid) exceeds about 300. In the presence of shear, the corresponding \textcolor{blue}{imperfect bifurcation} enhances the extensional rate of the flow in the wake. Consequently, the streamwise vortices generated behind the droplet can be more intense compared to those behind a clean bubble. Given the close relation between the lift force and the streamwise vorticity, a droplet with $\Rey=O(100)$ and $\mu^\ast\approx1$ typically experiences a greater lift force than that in the inviscid limit.

The buoyancy-driven motion of a deformable bubble rising near a vertical hydrophilic wall is studied numerically. We focus on moderately inertial regimes in which the bubble undergoes low-to-moderate deformations and would rise in a straight line in the absence of the wall. Three different types of near-wall motion are observed, depending on the buoyancy-to-viscous and buoyancy-to-capillary force ratios defining the Galilei ($Ga$) and Bond ($Bo$) numbers of the system, respectively. For low enough $Ga$ or large enough $Bo$, bubbles consistently migrate away from the wall. Conversely, for large enough $Ga$ and low enough $Bo$, they perform periodic near-wall bounces. At intermediate $Ga$ and $Bo$, they are first attracted to the wall down to a certain critical distance, and then perform bounces with a decreasing amplitude before stabilizing at this critical separation. Periodic bounces are accompanied by the shedding of a pair of streamwise vortices in the wake, the formation of which is governed by the near-wall shear resulting from the no-slip condition. These vortices provide a repulsive force that overcomes the viscous resistance of the fluid to the departing motion, making the bubble capable of returning to the region where it is attracted again to the wall. Although periodic, the shedding/regeneration cycle of these vortices is highly asymmetric with respect to the lateral bubble displacements, vortices being shed when the gap left between the bubble and the wall reaches its maximum, and reborn only when this gap comes back to its minimum.

This research shows how environmental impacts of products could be tracked based on semantic data and environmental impact calculations with the example of secondary copper production and the subsequent production of copper alloys, namely bronze and brass, with a focus on greenhouse gas emissions mainly termed as global warming potential (GWP). Utilizing copper scrap and waste printed circuit boards (PCBs) as feed materials, three simulation cases were examined: 100 wt.% copper scrap (CuScrap), a mix of 50 wt.% copper scrap and 50 wt.% PCBs (Mix), and 100 wt.% PCBs (PCBs). The study employed HSC Sim and FactSage software to model the overall process, including shredding, smelting, fire refining, electrorefining and alloying as the main unit processes. Life cycle assessment (LCA) was conducted using OpenLCA software and the ecoinvent 3.8 database to evaluate the environmental impacts comprehensively. The GWP results indicated variations across all the studied cases, with bronze production generally exhibiting higher impacts i.e. 33.46%, 32.33%, and 32.41% for CuScrap, Mix, and PCB cases, respectively, as compared to brass production due to the presence of tin (in bronze) which exhibits 3.7 times higher emissions than zinc (present in brass). The results revealed that emissions from the burning of plastics in PCBs significantly contributed to the overall emissions (e.g. 10.21% in the bronze production in PCB case), highlighting the importance of mitigating measures such as plastic separation prior to the shredding or smelting. Moreover, it was observed that the precious metals present in the PCBs shared a significant portion of the emissions because of their high market value. Overall, the results showed that it is possible to store and track material and its production impacts through multiple process steps based on the processes described by an ontology and assignable impacts.

The computational design of ionic materials such as ceramics relies on accurate enthalpies. While standard electronic structure approaches based on density functional theory can provide quantitatively accurate results for intermetallic compounds, they fail to yield a proper description of the thermodynamics of ionic materials such as oxides with mean absolute errors for formation enthalipies on the order of several hundred meV/atom. This hinders the materials design of for instance high-entropy ceramics or lower dimensional systems such as 2D oxides.
To address this pressing issue, we have recently developed the coordination corrected enthalpies (CCE) method based on the number of cation-anion bonds and the cation oxidation states. This correction scheme founded on the bonding topology decreases the prediction errors by almost an order of magnitude down to the room temperature thermal energy scale of ~25 meV/atom for oxides, halides, and nitrides. It is also capable of correcting the relative stability of crystal polymorphs. The efficient implementation of this scheme into the AFLOW framework for materials design in the form of the AFLOW-CCE module enables now the correction of enthalpies in large materials databases as well as for the construction of convex hull phase diagrams. These computational advances are thus an important enabler for the design of novel high-entropy ceramics.

Isostructural trivalent lanthanide and actinide amidinates bearing the N,N'-bis(isopropyl)benzamidinate (iPr2BA) ligand [LnIII/AnIII(iPr2BA)3] (Ln = La, Nd, Sm, Eu, Yb, Lu; An = U, Np) have been synthesized and characterized in both solid and solu-tion states. All compounds were examined in the solid state utilizing single crystal X-ray diffraction (SC-XRD), revealing a nota-ble deviation in the actinide series with shortened bond lengths compared to the trend in the lanthanide series, suggesting a non-ionic contribution to the actinide–ligand bonding. Quantum-chemical bonding analysis further elucidated the nature of these inter-actions, highlighting increased covalency within the actinide series, as evidenced by higher delocalization indices and greater 5f orbital occupation, except for Th(III) and Pa(III), which demonstrated substantial 6d orbital occupancies. An in-depth paramag-netic NMR study in solution also shed light on the covalent character of actinide–ligand bonding, with the separation of pseudo-contact (PCS) and contact shift (FCS) contributions employing the BLEANEY and REILLEY method. This analysis unveiled signifi-cant contact contributions in the actinide complexes, indicating enhanced covalency in actinide–ligand bonding. To corroborate these observations, an accurate PCS calculation method based on the KUPROV equation, incorporating both the distribution of electronic spin density and magnetic susceptibility obtained from CASSCF calculations, was applied and compared with experi-mental values

Worldwide, substantial amounts of the primary energy converted are lost
as waste heat. Since most of this heat is of low grade, suitable technologies
for conversion into electricity are limited and therefore new ones must be
developed. Here we present our thermoelastic generator for conversion of
low grade waste heat into electricity. It employs two sets of 1mm thick
NiTi wires in a protagonist-antagonist setup. This means, that a portion of
the generated actuation force of the transformation at one side is used to
prestrain the other. First, we present finite element models of the system,
which we used for the optimization of the conversion efficiency. We model the
heat to mechanical energy conversion with a coupling of computational fluid
dynamics, solid mechanics and heat exchange modules in COMSOL Multiphysics
®. From these simulation we derive and present design guidelines
for thermoelastic harvesting systems. Second, we show the simulation and
experimental data of the novel fluid chamber, which enables heat exchanges
rates upwards of 10 Hz, thus increasing the power output of the system.
Third, we present experimental data from the thermoelastic generator itself
and lastly we put shape memory alloy based harvesting into context to other
harvesting technologies and give an overview of the pros and cons of using
shape memory alloys for harvesting low grade waste heat.

Radiotherapy treatment-response of cancer patients can vary considerably, even in patients sharing the same diagnosis. Enhancing the degree of treatment personalization might offer a way towards improving curation rates. The recent advancements in the field of deep neural networks provide new directions for the non-invasive extraction of patient-individual biomarkers when applied on diagnostic imaging data.
Within this thesis, we explored the potential of image-based deep learning as an enabler for individualized therapy.
In a cohort of head and neck cancer patients, we first assessed the suitability of applying convolutional neural networks (CNNs) on pre-treatment computed tomography imaging data for the prediction of loco-regional tumor control in the presence of censored outcomes.
We further investigated whether the predictive performance can be improved through the adoption of multitask learning strategies that combine multiple outcome prediction models and a tumor segmentation task, both for CNNs and the recently emerged vision transformer-based network architectures.
Subsequently, we applied neural networks on multimodal and longitudinal imaging data collected during the course of radiotherapy and evaluated their potential to further improve outcome models.
Finally, in the context of proton-beam radiotherapy of primary brain tumor patients, we applied CNNs for the prediction of the linear energy transfer and examined the feasibility of this approach for estimating treatment-related side-effects considering a variable biological effectiveness of protons.

The surge in battery demand for both mobility and stationary applications necessitates a critical examination of the environmental impacts associated with battery material production and disposal. Key components such as cathodes, anodes, separators, and electrolytes contribute to environmental degradation throughout their supply chain, emphasizing the urgency for sustainable solutions. Circular economy principles offer a strategic framework for mitigating these impacts by promoting extended product lifecycles and increased utilization of recycled materials. This paradigm shift aims to minimize resource extraction and waste generation, thereby reducing greenhouse gas emissions, toxic exposure, and resource depletion. While challenges persist in achieving perfect circularity due to technical and logistical complexities, embracing the circular economy presents a promising avenue for enhancing sustainability in battery manufacturing and usage. The optimization of hydromechanical Li-ion battery recycling systems involves a multifaceted process encompassing material flow analysis and various mechanical, physical, and metallurgical processing units. The Simulation models utilizing advanced software aid in understanding material composition and flow dynamics, crucial for applying Design for Recycling Principles. Exergy calculation within a thermoeconomic framework further evaluate resource efficiency of the recycling route, and analytical techniques such as ICP-OES and XRD analysis play pivotal roles in identifying complex constituents and guiding process optimization. Regenerated lithium salt assumes integral significance in NMC battery production. This paper underscores the importance of efficient material recovery and recycling in sustainable battery production, emphasizing its critical role in meeting the demands of a greener future.

In order to improve energy and carbon dioxide efficiency of energy intensive industrial processes
the required design optimisations demand simulation tools for reliable predictions of dynamics in gas-
liquid flows. Appropriate modelling strategies always come with a trade-off between precision and
computational cost. In order to account for that, several individual numerical approaches are combined
in hybrid models, one of which is the MultiMorph model [1]. The latter comprises a Volume-of-Fluid
like treatment of large-scale interfaces united with an Euler-Euler model for small-scale dispersed
multiphase structures. The goal is to obtain consistent results across a wide range of spatial resolutions.
In that context, gas-liquid interfaces, being characterised by a shear boundary layer at each of both
sides, inevitably have to be depicted on computational grids with coarse resolution. This requires
adaptive modelling of the momentum exchange across the interface. Coste [2] proposes a model for
interfacial momentum exchange with the interface being smeared across exactly three grid cells by
definition. We propose an extension of the former approach and apply it to the MultiMorph model, in
which the smearing of the interface is not limited to a certain number of grid cells a-priori. The necessary
information from each side of the interface is transported across the interfacial region by means of the
interface transport algorithm of Meller et al. [3]. Results are assessed in several co-current horizontal
channel flows of Fabre et al. [4]. This contributes to numerical modelling with an enhanced predictive
power of gas-liquid interface dynamics in general and of interfacial momentum exchange on coarse
computational grids in particular.

Antiferromagnetic insulators are a prospective material science platform for magnonics, spin superfluidity, THz spintronics and non-volatile data storage. Due to linear magnetoelectric effect at room temperature, Cr2O3 is a convenient playground to test fundamental predictions and new device ideas. In this presentation, we will cover our activities on physics and applications of Cr2O3. In particular, we discovered a novel surface-symmetry-induced Dzyaloshinskii-Moria interaction at the nominally magnetically compensated crystallographic cuts of Cr2O3, which enables readout of the antiferromagnetic state using magnetotransport measurements [1]. We identified spin Hall magnetoresistance as a possible mechanism to explain all-electric readout of the magnetic state of insulating Cr2O3 interfaced with a heavy metal like Pt. The possibility to read-out the antiferromagnetic order parameter of magnetoelectric Cr2O3 all-electrically enabled realisation of antiferromagnetic magnetoelectric random access memory (AF-MERAM) [2]. Furthermore, we will discuss the family of flexomagnetic effects in Cr2O3 thin films [3]. It is demonstrated that in addition to the conventional magnetic moment induced by the strain gradient, there is another flexomagnetic effect which impacts the magnetic phase transition resulting in the distribution of the Néel temperature along the film thickness. The details on the study of the defect nanostructure in Cr2O3 thin films [4,5] and bulks [6] and their impact on magnetism and magnetoelectricity of Cr2O3 will be discussed as well.

[1] O. V. Pylypovskyi et al., “Surface-Symmetry-Driven Dzyaloshinskii-Moriya Interaction and Canted Ferrimagnetism in Collinear Magnetoelectric Antiferromagnet Cr2O3”. Phys. Rev. Let. 132, 226702 (2024).
[2] T. Kosub et al., “Purely antiferromagnetic magnetoelectric random access memory”. Nature Comm. 8, 13985 (2017).
[3] P. Makushko et al., “Flexomagnetism and vertically graded Néel temperature of antiferromagnetic Cr2O3 thin films”. Nature Comm. 13, 6745 (2022).
[4] I. Veremchuk et al., “Defect nanostructure and its impact on magnetism of α-Cr2O3 thin films”. Small 18, 2201228 (2022).
[5] O. V. Pylypovskyi et al., “Interaction of Domain Walls with Grain Boundaries in Uniaxial Insulating Antiferromagnets”. Phys. Rev. Applied 20, 014020 (2023).
[6] I. Veremchuk et al., “Magnetism and magnetoelectricity of textured polycrystalline bulk Cr2O3 sintered in conditions far out of equilibrium”. ACS Appl. Electron. Mater. 4, 2943 (2022).

Motion sensing is the primary task in numerous disciplines including industrial and soft robotics, prosthetics, virtual and augmented reality appliances. In rigid electronics, rotations, displacements and vibrations are typically monitored using magnetic field sensors. Here, we will discuss on the fabrication of flexible, stretchable and printable magnetoelectronic devices. The technology platform relies on high-performance magnetoresistive and Hall effect sensors either deposited or printed on polymeric foils. These skin conformal flexible and printable magnetosensitive elements enable touchless interactivity with surroundings based on the interaction with magnetic fields. This is relevant for soft robotics [1] and human-machine interfaces based on smart skins [2-4] and smart wearables [5]. In particular, reconfigurable magnetic origami actuators [1] can be equipped with ultrathin and lightweight magnetosensitive e-skins [6], which help to assess the magnetic state of the actuator (magnetized vs. non-magnetized), decide on its actuation pattern and control sequentiality and quality of the folding process. The on-board sensing adds awareness to soft-bodied magnetic actuators enabling them to act and be controlled similar to conventional robotic devices [7]. Magnetic soft robots can be designed to perform complex collaborative tasks being driven using magnetic far fields [1] and near fields [8]. The use of magnetic near fields of on-board electromagnetic coils to drive embedded permanent magnets can provide the demanded tuneability to the mechanical strength of grippers working with objects of different stiffness including biological tissues [9]. Furthermore, we will introduce printed magnetic field sensors that can be flexible [10], stretchable [4], and capable of detection in a broad range of magnetic fields. By an appropriate choice of the polymeric binder, these solution processable magnetoelectronics can self-heal upon mechanical damage [11]. This research motivates further explorations towards the realisation of eco-sustainable magnetoelectronics. To this end, we will discuss biocompatible and biodegradable magnetosensitive devices, which can help to minimise electronic waste and bring magnetoelectronics to new application fields in medical implants and health monitoring.

[1] M. Ha et al., Reconfigurable magnetic origami actuators with on-board sensing for guided assembly. Adv. Mater. 33, 2008751 (2021).
[2] G. S. Canon Bermudez et al., Electronic-skin compasses for geomagnetic field driven artificial magnetoreception and interactive electronics. Nature Electronics 1, 589 (2018).
[3] J. Ge et al., A bimodal soft electronic skin for tactile and touchless interaction in real time. Nature Communications 10, 4405 (2019).
[4] M. Ha et al., Printable and stretchable giant magnetoresistive sensors for highly compliant and skin-conformal electronics. Adv. Mater. 33, 2005521 (2021).
[5] P. Makushko et al., Flexible magnetoreceptor with tunable Intrinsic logic for on-skin touchless human-machine interfaces. Adv. Funct. Mat. 31, 2101089 (2021).
[6] G. S. Canon Bermudez et al., Magnetosensitive e-skins for interactive devices. Adv. Funct. Mater. (Review) 31, 2007788 (2021).
[7] E. S. Oliveros Mata et al., Magnetically aware actuating composites: Sensing features as inspiration for the next step in advanced magnetic soft robotics. Phys. Rev. Appl. (Review) 20, 060501 (2023).
[8] M. Richter et al., Locally addressable energy efficient actuation of magnetic soft actuator array systems. Advanced Science 2302077 (2023).
[9] L. Masjosthusmann et al., Miniaturized Variable Stiffness Gripper Locally Actuated by Magnetic Fields. Advanced Intelligent Systems 2400037 (2024).
[10] E. S. Oliveros Mata et al., Dispenser printed bismuth-based magnetic field sensors with non-saturating large magnetoresistance for touchless interactive surfaces. Adv. Mater. Technol. 7, 2200227 (2022).
[11] R. Xu et al., Self-healable printed magnetic field sensors using alternating magnetic fields. Nature Communications 13, 6587 (2022).

Extending 2D structures into 3D space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics, superconductivity and magnetism [1,2]. This approach provides means to modify conventional or to launch novel functionalities by tailoring curvature and 3D shape of magnetic thin films and nanowires [2,3]. In this talk, we will address fundamentals of curvature-induced effects in magnetism and review the envisioned application scenarios. In particular, we will demonstrate that curvature allows tailoring fundamental anisotropic and chiral magnetic interactions [4] and enables fundamentally new non-local chiral symmetry breaking effect [5,6]. Application potential of geometrically curved magnetic architectures is currently being explored as mechanically reshapeable magnetic field sensors for automotive applications, memory, spin-wave filters, high-speed racetrack memory devices, magnetic soft robotics [7] as well as on-skin interactive electronics relying on thin films [8,9,10] as well as printed magnetic composites [11,12] with appealing self-healing performance [13].

[1] P. Gentile et al., Electronic materials with nanoscale curved geometries. Nature Electronics (Review) 5, 551 (2022).
[2] D. Makarov et al., New Dimension in Magnetism and Superconductivity: 3D and Curvilinear Nanoarchitectures. Advanced Materials (Review) 34, 2101758 (2022).
[3] D. Makarov et al., Curvilinear micromagnetism: from fundamentals to applications (Springer, Zurich, 2022).
[4] O. Volkov et al., Experimental observation of exchange-driven chiral effects in curvilinear magnetism. Physical Review Letters 123, 077201 (2019).
[5] D. D. Sheka et al., Nonlocal chiral symmetry breaking in curvilinear magnetic shells. Communications Physics 3, 128 (2020).
[6] O. M. Volkov et al., Chirality coupling in topological magnetic textures with multiple magnetochiral parameters. Nature Communications 14, 1491 (2023).
[7] M. Ha et al., Reconfigurable Magnetic Origami Actuators with On-Board Sensing for Guided Assembly. Advanced Materials 33, 2008751 (2021).
[8] G. S. Canon Bermudez et al., Magnetosensitive e-skins for interactive devices. Advanced Functional Materials (Review) 31, 2007788 (2021).
[9] J. Ge et al., A bimodal soft electronic skin for tactile and touchless interaction in real time. Nature Communications 10, 4405 (2019).
[10] G. S. Canon Bermudez et al., Electronic-skin compasses for geomagnetic field driven artificial magnetoception and interactive electronics. Nature Electronics 1, 589 (2018).
[11] M. Ha et al., Printable and Stretchable Giant Magnetoresistive Sensors for Highly Compliant and Skin-Conformal Electronics. Advanced Materials 33, 2005521 (2021).
[12] E. S. Oliveros Mata et al., Dispenser printed bismuth-based magnetic field sensors with non-saturating large magnetoresistance for touchless interactive surfaces. Adv. Mater. Technol. 7, 2200227 (2022).
[13] R. Xu et al., Self-healable printed magnetic field sensors using alternating magnetic fields. Nature Communications 13, 6587 (2022).

Curvilinear magnetism is a framework, which helps understanding the impact of geometric curvature on complex magnetic responses of curved 1D wires and 2D shells [1-3]. The lack of the inversion symmetry and the emergence of a curvature induced effective anisotropy and Dzyaloshinskii-Moriya interaction (DMI) stemming from the exchange interaction [4,5] are characteristic of curved surfaces, leading to curvature-driven magnetochiral effects. The exchange-driven chiral effects in curvilinear ferromagnets are experimental observables [6] and can be used to realize low-dimensional architectures with tunable magnetochiral properties based on standard magnetic materials. In particular, magnetochiral responses of any curvilinear ferromagnetic nanosystem are governed by the mesoscale DMI, which is determined via both the material and geometrical parameters [7]. Its strength and orientation can be tailored by properly choosing the geometry, which allows stabilizing distinct magnetic chiral textures including skyrmion and skyrmionium states as well as skyrmion lattices [8-10]. 
Curvilinear sample geometries support novel nonlocal chiral symmetry breaking effect, which manifests itself even in static spin textures [5]. The combined experimental and theoretical study revealed that the nonlocal chiral symmetry breaking is responsible for the coexistence and coupling of multiple magnetochiral properties within the same magnetic object [11]. 
The topology of the geometry of curvilinear magnetic objects sets a strict constraint on the magnetization vector field. For the specific case of soft magnetic wireframe structures, topological properties of their surface determine uniquely the number and type of magnetic solitons [12]. For instance, magnetic N-pods are topologically equivalent to a sphere and hence support N vortices and N-2 antivortices (i.e., 2N-2 magnetic solitons per object). Even more interesting that it is possible to realise objects with topology of N-torus, which can support only one type of magnetic solitons. Yet these are antivortices but not vortices. In 3D geometries, the prevailing type of magnetic solitons is antivortices rather than vortices. For instance, 4-torus supports 6 antivortices only. The key aspect is that these are solitons of the same type which do not annihilate upon interaction. Hence, they are attractive for implementation of reservoir and neuromorphic computing. In particular, the stability of antivortex lattices combined with spin-wave propagation into wireframe structures may be useful for potential application in magnonic-based computing.
These new fundamental discoveries will be covered in this presentation. 

References
[1] D. Makarov et al., Curvilinear micromagnetism: from fundamentals to applications (Springer, Zurich, 2022).
[2] D. Makarov et al., Advanced Materials (Review) 34 (2022) 2101758.
[3] D. D. Sheka et al., Small (Review) 18 (2022) 2105219.
[4] Y. Gaididei et al., Phys. Rev. Lett. 112 (2014) 257203.
[5] D. Sheka et al., Communications Physics 3 (2020) 128.
[6] O. Volkov et al., Phys. Rev. Lett. 123 (2019) 077201.
[7] O. Volkov et al., Scientific Reports 8 (2018) 866.
[8] V. Kravchuk et al., Phys. Rev. B 94 (2016) 144402.
[9] V. Kravchuk et al., Phys. Rev. Lett. 120 (2018) 067201.
[10] O. Pylypovskyi et al., Phys. Rev. Appl. 10 (2018) 064057.
[11] O. Volkov et al., Nature Commun. 14 (2023) 1491.
[12] O. Volkov et al., Nature Commun. 15 (2024) 2193.

In this presentation, we will discuss on our activities on magnetic soft robots. The focus will be on the possibility to actuate these objects using on-board magnetic coils and sense their state using on-board skin-conformal magnetic field sensors.

The design of novel materials for various scientific and technological purposes has in recent years benefitted from the introduction of data-driven methods. Here, this will be demonstrated for two exemplary materials classes.
While two-dimensional (2D) materials are traditionally derived from bulk layered compounds bonded by weak van der Waals (vdW) forces, the recent surprising experimental realization of non-vdW 2D compounds obtained from non-layered crystals [1] foreshadows a new direction in 2D systems research. We present several dozens of candidates of this novel materials class derived from applying data-driven research methodologies in conjunction with autonomous ab initio calculations [2,3]. Surface passivation of these systems can be used to control their magnetic state and eventually even to induce ferromagnetism [4]. The candidates thus exhibit a wide range of appealing electronic, optical, and magnetic properties making them an attractive platform for fundamental and applied nanoscience.
Also high-entropy materials have recently attracted significant interest due to their favorable mechanical, catalytic, and electronic properties. For the actual design of high-entropy materials, predictive synthesizability descriptors such as the disordered enthalpy-entropy descriptor (DEED) [5] are crucial prerequisites. We present an extensive validation of the predictive power of this approach and its prospective combination with enthalpy corrections for ionic materials [6]. These findings might thus pave the way towards an efficient computational design of high-entropy compounds for extreme conditions.

[1] A. Puthirath Balan et al., Nat. Nanotechnol. 13, 602 (2018).
[2] R. Friedrich et al., Nano Lett. 22, 989 (2022).
[3] T. Barnowsky et al., Adv. Electron. Mater. 9, 2201112 (2023).
[4] T. Barnowsky et al., Nano Lett. 24, 3874 (2024).
[5] S. Divilov et al., Nature 625, 66 (2024).
[6] R. Friedrich et al., npj Comput. Mater. 5, 59 (2019).

The design of novel materials for various scientific and technological applications has in recent years benefitted from the introduction of data-driven methods. Here, this will be demonstrated for two exemplary materials classes.

While two-dimensional (2D) materials are traditionally derived from bulk layered compounds bonded by weak van der Waals (vdW) forces, the recent surprising experimental realization of non-vdW 2D compounds obtained from non-layered crystals [1] foreshadows a new direction in 2D systems research. We present several dozens of candidates of this novel materials class derived from applying data-driven research methodologies in conjunction with autonomous ab initio calculations [2,3]. Surface passivation of these systems can be used to control their magnetic state and eventually even to induce ferromagnetism [4]. The candidates thus exhibit a wide range of appealing electronic, optical and magnetic properties making them an attractive platform for fundamental and applied nanoscience.

Also high entropy materials have recently attracted significant interest due to their favorable mechanical, catalytic, and electronic properties. High-entropy ceramics consist of an ordered anion sublattice of carbon, nitrogen or oxygen and a disordered cation sublattice maximizing configurational entropy by randomly occupying it by five or more cation species (transition metal elements). The reliable computational modelling of such systems can be realized by expanding it into a large ensemble of ordered structures [5]. For the actual realization of high-entropy materials, predictive synthesizability descriptors such as the entropy-forming ability (EFA) [6] and the disordered enthalpy-entropy descriptor (DEED) [7] are crucial prerequisites. We present here extensive results validating the predictive power of these approaches. These findings thus pave the way towards an efficient computational design of high-entropy compounds for extreme conditions.

[1] A. Puthirath Balan et al., Nat. Nanotechnol. 13, 602 (2018).
[2] R. Friedrich et al., Nano Lett. 22, 989 (2022).
[3] T. Barnowsky et al., Adv. Electron. Mater. 9, 2201112 (2023).
[4] T. Barnowsky et al., Nano Lett. 24, 3874 (2024).
[5] K. Yang et al., Chem. Mater. 28, 6484 (2016).
[6] P. Sarker et al., Nat. Commun. 9, 4980 (2018).
[7] S. Divilov et al., Nature 625, 66 (2024).

Skin-friction causes a large portion of energy consumption of water vessels. Air lubrication (the injection of air beneath a ship hull) is a promising technology to reduce frictional resistance and improve energy efficiency in maritime transport. It can lead to significant fuel cost savings of up to 8%, or even 12%. The effectiveness of air lubrication systems is, however, strongly influenced by various factors, including the method of air injection and ship operating conditions. The air injection beneath the ship hull results in one of the three air lubrication regimes: bubble drag reduction (BDR), air layer drag reduction (ALDR), or a transitional state. The present work assesses the capability of the morphology-adaptive MultiMorph method to predict the phenomena related to air lubrication. The method is particularly suitable as it allows to capture instantaneous transitions between different morphologies (bubbles, air layer). It is validated against flat plate experiments featuring various combinations of water velocity and gas flow rate. The application of MultiMorph to a full ship hull geometry is demonstrated.

Establishing accurate chronological frameworks is imperative for reliably identifying lead-lag dynamics within the climate system and enabling meaningful inter-comparisons across diverse paleoclimate proxy records over long time periods. Robust age models provide a solid temporal foundation for establishing correlations between paleoclimate records. One of the primary challenges in constructing reliable radiocarbon-based chronologies in the marine environment is to determine the regional marine radiocarbon reservoir age correction. Calculations of the local marine reservoir effect (ΔR) during deglaciation can be acquired using 14C-independent dating methods, such as synchronization with other well-dated archives. The cosmogenic radionuclide 10Be offers such a synchronization tool. Its atmospheric production rate is affected by the global modulations driven by fluctuations in the cosmic ray influx, caused by variations in solar activity and geomagnetic field strength. The resulting fluctuations in the meteoric deposition of 10Be are preserved in sediments and ice cores and can thus be utilized for their synchronization. In this study, for the first time, we use the authigenic 10Be/9Be record of a Laptev Sea sediment core for the period 8-14 kyr BP and synchronize it with the 10Be records from absolutely dated ice cores. Based on the resulting absolute chronology, a benthic ΔR value of +345±60 14C years was estimated for the Laptev Sea, which corresponds to a marine reservoir age of 848±90 14C years. The ΔR value was used to refine the age-depth model for core PS2458-4, establishing it as a reference chronology for the Laptev Sea. We also compare the calculated ΔR value with modern estimates from the literature and discuss its implications for the age-depth model.

Mineral dissolution is an important process that occurs in both natural as well as anthropogenic processes. The kinetics of such dissolution processes are influenced not only by the characteristics of the solution but also by the characteristics of the minerals, such as crystal defects on the microscopic scale or macroscopic features such as the intersection of crystal planes to form edges and corners. Macroscopic features are known to increase the population of steps and kinks that may, in turn, affect the dissolution rate over time. Hence, this study presents a 3D empirical dissolution model aimed at examining the time-series evolution of macroscopic features together with the corresponding changes in the dissolution rate under far from equilibrium batch reactor conditions. The developed empirical model is based on the mineral geometry (surface topography and volume) derived from X-ray computed tomography (CT) measurements. The macroscopic features are identified using surface curvature which are then used to generate reactivity maps for dissolution model. As a study case, the dissolution of monomineralic galena (PbS) in ethaline and iodine as oxidizing agent is experimentally observed and then modelled. The model is then applied to seven particles of various shapes and sizes. The finding suggests that the surface reactivity increases over time as the particle shrinks and the macroscale steps and edges become dominant over the initial terraces. This implies that the persistent highly reactive surface sites defined by a particle’s geometry may play a dominant role in the overall particle dissolution in addition to the dissolution mechanisms typically studied on near atomic-flat surfaces. The model developed in this investigation offers the opportunity to be extended providing the possibility of simulating the dissolution of multi-mineral particles during batch dissolution experiments.

This contribution will demonstrate an interactive open-access GUI that aims to standardize a protocol to plan and to assess the feasibility of CT experiments. This standardization promotes quality assurance and improves comparability of laboratory source CT images obtained in different facilities.
The planning of a CT experiment consists of converging the preliminary knowledge about the sample with the technique requirements in order to answer specific scientific questions. This often involves combining the expertise of a “User” and a “CT expert”. The User is an expert in a specific field of science related to the sample and has formulated specific scientific questions or hypothesis that may be answered using CT. The CT expert is a person with advanced knowledge of CT, who does not necessarily have an in-depth knowledge about the specific field of science related to the experiment.

X-ray computed micro tomography (CT) is the main 3D technique for imaging the internal microstructures of samples. Experimental planning is crucial to ensure the adequacy of CT results to answer specific scientific questions, optimizing the use of resources and maximizing the quality of results. Proper planning requires a certain level of expertise in the technique and the details of the specific scientific question to be answered. Notably, potential new CT users who have formulated a scientific question may not have the in-depth knowledge about CT necessary to make a first assessment of whether CT is suitable for their work.
Here, a step-by-step protocol to plan CT experiments and an interactive graphical user interface (XCT-Explorer) are proposed to guide users through the different steps of the protocol and to link the various CT parameters required to perform a scan. The XCT-Explorer can be accessed at https://xct-explorer-v1.streamlit.app/. The protocol is based on the experience gained within the EXCITE community through interactions between facility managers and users from various scientific fields. The planning protocol aims to 1) help potential CT users with limited knowledge of CT (e.g. first-time users) to decide whether CT can answer their scientific question; 2) guide users to decide which parameters are the most appropriate for their sample / problem; 3) facilitate the initial contact between CT provider and new users; and 4) standardize the planning stage of CT experiments as the foundation for FAIR practices.

Bubble column reactors are the most commonly used equipment for generating gas-liquid
reactions and play a vital role in the chemical and process engineering. An understanding of the
hydrodynamics is crucial for controlling the rate of reaction in such devices and for optimizing
their design. On the component-scale the two-fluid model is the state-of-the-art approach, but
relies heavily on the accuracy, performance and generality of closure models. Continuous
efforts to improve these models benefit from the steadily growing amount of validation data
that is generated from experiments.

The Al18F-labeling approach offers a one-step access to radiofluorinated biomolecules by mimicking the labeling process for radiometals. Although these labeling conditions are considered to be mild compared to classic radiofluorinations, improvements of the chelating units have led to the discovery of (±)-H3RESCA, which allows Al18F-labeling already at ambient temperature. While the suitability of (±)-H3RESCA for functionalization and radiofluorination of proteins is well established, its use for small molecules or peptides is less explored. Herein, we advanced this acyclic pentadentate ligand by introducing an alkyne moiety for the late-stage functionalization of biomolecules via click chemistry. We show that in addition to Al18F-labeling, the cyclohexanediamine triazole (CHDT) moiety allows stable complexation of 68Ga and 111In. Three novel CHDT-functionalized PSMA inhibitors were synthesized and their Al18F-, 68Ga-, and 111In-labeled analogs were subjected to a detailed in vitro radiopharmacological characterization. Stability studies in vitro in human serum revealed amongst others a high kinetic inertness of all radiometal complexes. Furthermore, the Al18F-labeled PSMA ligands were characterized for their biodistribution in a LNCaP derived tumor xenograft mouse model by PET imaging. One radioligand, Al[18F]F-CHDT-PSMA-1, bearing a small azidoacetyl linker at the glutamate-urea-lysine motif, provided an in vivo performance comparable to that of [18F]PSMA-1007, but with even higher tumor-to-blood and tumor-to-muscle ratios at 120 min p.i. Overall, our results highlight the suitability of the novel CHDT moiety for functionalization and radiolabeling of small molecules or peptides with Al18F, 68Ga, and 111In and the triazole ring seems to entail favorable pharmacokinetic properties for molecular imaging purposes.

Using advanced in situ transmission electron microscopy, we study the lithiation and delithiation processes into graphene sheets and detect significant differences in the structural evolution of the system. Thin fcc lithium crystals with faceted shapes are formed between
graphene sheets during lithiation, but are transformed into irregular patches during delithiation. We find that defects such as vacancies in graphene and impurity atoms play the key role in these processes. Specifically, during intercalation the lithium crystals nucleate at vacancies in graphene, while upon delithiation the impurity oxygen atoms initially embedded at octahedral interstitial positions inside the lithium crystals agglomerate at the edges of the crystals, thus giving rise to the formation of amorphous lithium oxide patches, where lithium ions are trapped.

Femtosecond laser-induced ultrafast magnetization dynamics are all-optically probed for different remanent magnetic domain states of a [Co/Pt]22 multilayer sample, thus revealing the tunability of the direct transport of spin angular momentum across domain walls. A variety of different magnetic domain configurations (domain wall origami) at remanence achieved by applying different magnetic field histories are investigated by time-resolved magneto-optical Kerr effect magnetometry to probe the ultrafast magnetization dynamics. Depending on the underlying domain landscape, the spin-transport-driven magnetization dynamics show a transition from typical ultrafast demagnetization to being fully dominated by an anomalous transient magnetization enhancement (TME) via a state in which both TME and demagnetization coexist in the system. Thereby, the study reveals an extrinsic channel for the modulation of spin transport, which introduces a route for the development of magnetic spin-texture-driven ultrafast spintronic devices.

Perpendicular magnetic anisotropy thin film systems are well known for their periodic magnetic stripe domain structures. In this study, we focus on investigating the behavior of [Co(3.0 nm)/Pt(0.6 nm)]X multilayers within the transitional regime from preferred in-plane to out-of-plane magnetization orientation. Particularly, we examine the sample with X = 11 repetitions, which exhibits a remanent state characterized by a significant presence of both out-of-plane (OOP) and in-plane (IP) magnetization components, here referred to as the “tilted” stripe domain state. Vector vibrating sample magnetometry and magnetic force microscopy are used to investigate this specific sample and its unusual out-of-plane reversal behavior. Through experimental data analysis and micromagnetic simulations of the tilted magnetization system, we identify a single point of irreversibility during an out-of-plane external magnetic field sweep. This behavior is qualitatively similar to the reversal of a Stoner-Wohlfarth particle or of an IP magnetized disk with remanent vortex structure, since both show distinct points of irreversibility as well. Such a collective response to an external field is typically not observed in conventional OOP or IP systems, where the reversal process often involves independent nucleation, propagation, and annihilation of individual domains. Finally, we show that our findings are not at all restricted to Co/Pt multilayers, but are a quite general feature of transitional in-plane to out-of-plane magnetization systems.

We carry out highly accurate ab initio path integral Monte Carlo (PIMC) simulations to directly
estimate the free energy of various warm dense matter systems including the uniform electron gas
and hydrogen without any nodal restrictions or other approximations. Since our approach is based
on an effective ensemble in a bosonic configuration space, it does not increase the computational
complexity beyond the usual fermion sign problem. Its application to inhomogeneous cases such as
an electronic system in a fixed external ion potential is straightforward and opens up the enticing
possibility to benchmark density functional theory and other existing methods. Finally, it is not
limited to warm dense matter, and can be applied to a gamut of other systems such ultracold atoms
and electrons in quantum dots.

We present two methods for computing the dynamic structure factor for warm dense hydrogen
without invoking either the Born-Oppenheimer approximation or the Chihara decomposition, by
employing a wave packet description which resolves the electron dynamics during ion evolution.
Firstly, a semiclassical method is discussed which is corrected based on known quantum constraints,
and secondly, a direct computation of the density-density response function within the molecular
dynamics. The wave packet models are compared to PIMC and DFT-MD for the static and low-
frequency behaviour. For the high-frequency behaviour the models recover the expected behaviour
in the limits of small and large momentum transfers and show the characteristic flattening of the
plasmon dispersion for intermediate momentum transfers due to interactions, in agreement with
commonly used models for X-ray Thomson scattering. By modelling the electrons and ions on
an equal footing, both the ion and free electron part of the spectrum can now be treated within
a single framework where we simultaneously resolve the ion-acoustic and plasmon mode, with a
self-consistent description of collisions and screening.

Presence of magnetism in potentially altermagnetic RuO₂ has been a subject of intense debate. Using broadband infrared spectroscopy combined with density-functional band-structure calculations, we show that optical conductivity of RuO₂, the bulk probe of its electronic structure, is well described by the nonmagnetic model of this material. The sharp Pauli edge demonstrates the presence of a Dirac nodal line lying 45 meV below the Fermi level. Good match between the experimental and ab initio plasma frequencies underpins weakness of electronic correlations. The intraband part of the optical conductivity indicates Fermi-liquid behavior with two distinct scattering rates below 150 K. Fermi-liquid theory also accounts for the temperature-dependent magnetic susceptibility of RuO₂ and allows a consistent description of this material as paramagnetic metal.

2D magnetic materials hold substantial promise in information storage and neuromorphic device applications. However, achieving a 2D material with high Curie temperature (T_C), environmental stability, and multi-level magnetic states remains a challenge. This is particularly relevant for spintronic devices, which require multi-level resistance states to enhance memory density and fulfil low power consumption and multi-functionality. Here, the synthesis of 2D non-layered triangular and hexagonal magnetite (Fe₃O₄) nanosheets are proposed with high T_C and environmental stability, and demonstrate that the ultrathin triangular nanosheets show broad antiphase boundaries (bAPBs) and sharp antiphase boundaries (sAPBs), which induce multiple spin precession modes and multi-level resistance. Conversely, the hexagonal nanosheets display slip bands with sAPBs associated with pinning effects, resulting in magnetic-field-driven spin texture reversal reminiscent of “0” and “1” switching signals. In support of the micromagnetic simulation, direct explanation is offer to the variation in multi-level resistance under a microwave field, which is ascribed to the multi-spin texture magnetization structure and the randomly distributed APBs within the material. These novel 2D magnetite nanosheets with unique spin textures and spin dynamics provide an exciting platform for constructing real multi-level storage devices catering to emerging information storage and neuromorphic computing requirements.

In dieser Bachelorarbeit wurde ein Testprogramm für die Validierung der Stromdichteberechnung in der Current-Deposition-Phase des Particle-in-Cell-Codes PIConGPU [13] entwickelt. Ausgehend von der (diskretisierten) Kontinuitätsgleichung und unter Nutzung des Prinzips von Cloud-Shapes nach Hockney sowie Esirkepovs Methode und dem daraus hergeleiteten Konstrukt des Current-Deposition-Vektors wird eine rekursive Methode zur Berechnung der Stromdichte eines geladenen Teilchens in einem Gitter konstruiert. Diese berechnete Stromdichte wird in einem Vergleichsprogramm genutzt, um sie bei gleicher Teilchenbewegung mit dem Ergebnis von PIConGPU zu vergleichen. Anhand der relativen Abweichung des simulierten Ergebnisses der Stromdichte verifiziert oder falsifiziert das Vergleichsprogramm die Current-Deposition von PIConGPU. Damit eine standardisierte Verwendung des Tests zu ermöglicht wird, wird er durch zwei Bash-Skripte automatisch ausgeführt, sobald eine Änderung am Code von PIConGPU vorgenommen wurde. Dadurch können Fehler frühzeitig erkannt werden und ein möglichst einfacher und schneller Arbeitsfluss wird gewährleistet.

A sealed container for the geological disposal of spent nuclear fuel and vitrified high-level waste is the
only component of the deep geological repository that provides complete containment of radionuclides.
As such, attention is focused on its lifetime. The lifetime of the container is influenced by materials
degradation processes during disposal and is typically of the order of several millennia and, for some
container materials, up to one million years. Designing, manufacturing, and predicting the performance
of containers over such long periods requires an in-depth understanding of their materials properties,
fabrication processes, and degradation mechanisms. Scientific and technological progress can improve
both the performance of containers as well as the robustness of lifetime predictions. For many national
radioactive waste disposal programs, optimization of these aspects is of primary importance. In this
paper, the state of the art of complex coupled degradation processes, as well as the optimization
potential of novel container materials is presented. Furthermore, the existing tools allowing the
prediction of long-term barrier integrity are discussed.

Plasma acceleration processes have garnered extensive research interest in recent years due to the versatile applications of high-energy X-rays, including medical diagnostics and treatment, semiconductor manufacturing, and the hardening of material surfaces. However, simulating these processes demands a complex workflow and considerable computational time, rendering in-situ analysis impractical. To mitigate these challenges, simulation-based inference and data-driven methods for one-step inversion can be utilized to recover the matching phase-space representation and elucidate the underlying physics.

This work presents the adaptation of a surrogate model specifically for plasma physics processes, such as beam transport in a Free Electron Laser (FEL). A previously proposed model, which uses a mixture of normalizing flows to learn multi-modal distributions, is systematically investigated. Conditionality as a means of surrogate modeling in plasma physics is investigated and trained on simulation results of plasma physics processes.

Initial experiments involved using various custom test distributions to derive key insights into the model’s operation. Conditionality was incorporated into the model by utilizing the single-view reconstruction provision appropriately, allowing it to handle a wider range of input conditions. This conditioning has been introduced in two forms, scalar conditioning, and one-hot vector conditioning, and the effectiveness of each method is studied. This redefined architecture was rigorously tested on various test distributions with differing characteristics to validate its performance. The reconstruction quality was then compared to point clouds generated by single normalizing flow-based models with similar network sizes. Additionally, a significant reduction in trainable parameters was achieved, making the model more computationally feasible. Custom training protocols were introduced to further reduce overall training time.

The enhanced architecture was subsequently applied to simulation data from a free electron laser. A comprehensive analysis of the results demonstrated the surrogate model’s capability to accurately capture the complex dynamics of plasma acceleration processes. This work highlights the potential of advanced surrogate models in reducing computational demands and providing deeper insights into plasma physics, paving the way for more efficient and practical applications in high-energy X-ray technologies.

Es wird der Cowan-Cole-Kärkkäinen (CCK) Maxwell Solver in PIConGPU implementiert und validiert. Der CCK Solver hat gegenüber dem standard Yee Solver den Vorteil, dass er entlang der Achse mit dem geringsten Gitterabstand dispersionsfrei ist. Dadurch wird beispielsweise bei Laser Wakefield Acceleration Simulationen keine numerische Cherenkov Strahlung erzeugt. Dabei wird die in der Simulation beobachtbare Phasengeschwindigkeit einer Welle mit den theoretischen Werten aus den numerischen Dispersionsrelationen verglichen.

Detecting near-infrared (NIR) light with high efficiency is crucial for photodetectors that are applied in optical communication systems. Si hyperdoped with deep-level impurities provides a monolithic platform for infrared optoelectronics with room-temperature operation at telecommunication wavelengths. In this work, we present strongly enhanced NIR absorption via the hybridization between plasmon resonance and mid-gap states in Au-hyperdoped Si layers, prepared by ion implantation and pulsed laser melting. The Au-hyperdoped Si layers exhibit high-quality recrystallization with the substitution of Au atoms into the Si matrix and the formation of Au nanoclusters on the surface. Surprisingly, the Au-hyperdoped Si layers exhibit a NIR absorption with spectral response extending up to 1650 nm and maximum absorptance up to 30%. According to the electromagnetic simulation, the enhanced infrared photoresponse can be attributed to the mid-gap states induced by substitutional Au atoms and the localized surface plasmon resonance associated with the Au nanoclusters. This work presents a simplified one-step process to gain significant enhancement of NIR absorption, which paves a way for the realization of Si-based photodetectors with room-temperature operation and outstanding performance.

The Helmholtz Senate has commissioned the Helmholtz Research Field Energy with the task of developing a science and technology driven roadmap for energy research. The prime objective of this Helmholtz Energy Transition Roadmap (HETR) is to offer strategic guidance to the Helmholtz Research Field Energy, especially during the planning process for the forthcoming funding period, known as the POF-V-process. It also aims to provide orientation to external stakeholders in science, industry and politics.
While the project is spearheaded by the Helmholtz Vice-President Energy, the content framework for the roadmap has been created by a small group of leading authors, under the advisory of a core team. These authors received significant support from roughly 100 scientists from the Research Field Energy, who contributed their specific expertise. These scientists, organized into several interdisciplinary Expert Groups, span the full range of research in materials, technologies, systems and society within the ESD, MTET and FUSION programs. To align our research objectives and challenges, these Expert Groups participated in multiple feedback loops contributing to the roadmap's development.

The onset of the primary instability of two-phase air-water stratified flow in a circular pipe was studied experimentally by two independent non-intrusive techniques. The techniques analyze the steady or oscillatory response of either a laser beam passing through the air-water interface, or of an echo of an ultrasound wave reflected from the interface. The experiments are accompanied by linear stability analysis performed in both Cartesian and bipolar coordinates, thus yielding two independently obtained numerical results for comparison. The critical values of the phases’ superficial velocities corresponding to the flow primary instability calculated numerically by the two independent methods agree well with each other. The computed stability diagram shows that instability sets in owing to long-wave disturbances at large holdups, while at smaller holdups, the most unstable perturbations appear as finite-length (short) waves. A comparison of the experimental and numerical results shows a good agreement for the long-wave instability. For the short-wave instability, the measured critical superficial velocities are below the computed ones, while the frequencies found experimentally for supercritical oscillatory flow states agree with the numerical predictions. Several additional peaks in the frequency spectra are observed in the experiments. By comparing these frequencies with the numerical spectra, we argue that they correspond to stable eigenmodes with close to zero decay rates, which can be triggered either by non-linear mechanisms, or become unstable because of experimental imperfections.

Change detection (CD) from remote sensing (RS) images using deep learning has been widely investigated in the literature. It is typically regarded as a pixel-wise labeling task that aims to classify each pixel as changed or unchanged. Although per-pixel classification networks in encoder-decoder structures have shown dominance, they still suffer from imprecise boundaries and incomplete object delineation at various scenes. For high-resolution RS images, partly or totally changed objects are more worthy of attention rather than a single pixel. Therefore, we revisit the CD task from the mask prediction and classification perspective and propose MaskCD to detect changed areas by adaptively generating categorized masks from input image pairs. Specifically, it utilizes a cross-level change representation perceiver (CLCRP) to learn multiscale change-aware representations and capture spatiotemporal relations from encoded features by exploiting deformable multihead self-attention (DeformMHSA). Subsequently, a masked cross-attention-based detection transformers (MCA-DETR) decoder is developed to accurately locate and identify changed objects based on masked cross-attention and self-attention mechanisms. It reconstructs the desired changed objects by decoding the pixel-wise representations into learnable mask proposals and making final predictions from these candidates. Experimental results on five benchmark datasets demonstrate the proposed approach outperforms other state-of-the-art models. Codes and pretrained models are available online (https://github.com/EricYu97/MaskCD).

Positron Profilometry . Can we overcome expensive facilities with new concepts?

I will discuss possible applications of RFQ-type 8Radio-Frequency Quadrupole) particle accelerators for efficient positron collection, bunching and post-acceleration im combination with radio-isotope based positron sources.

Radionuclide Theranostics – a fast-growing emerging field in radiopharmaceutical sciences and nuclear medicine – offers a personalized and precision treatment approach by combining diagnosis and specific and selective targeted endoradiotherapy. This concept is based on the application of the same molecule, labeled with radionuclides possessing complementary imaging and therapeutic properties, respectively. Ideally in radionuclide theranostics, radionuclide pairs consisting of the same element, such as ^61/64Cu/⁶⁷Cu, ²⁰³Pb/²¹²Pb or ^123/124I/¹³¹I, maintaining identical chemical and pharmacological characteristics are of significant interest. However, such "true matched pairs" are rare, necessitating the use of complementary radionuclides from different elements for diagnostics and endoradiotherapy with similar chemical characteristics, such as ^99mTc/^186/188Re, ⁶⁸Ga/¹⁷⁷Lu, ⁶⁸Ga/²²⁵Ac. Corresponding combinations of such two radionuclides in one and the same radioconjugate is referred to as a "matched pair". Notably, the pharmacological behavior remains consistent across both diagnostic and therapeutic applications with "true matched pairs", which may differ for “matched pairs”. Due to the fact that "true matched pairs" of theranostic radioisotopes are rare and that some relevant radionuclides do not fit with the diagnostic or therapeutic counterpart, the radionuclide theranostic concept can even be expanded and improved by the introduction of the so called radiohybrid approach.

The photoelectrochemical performance of Ta₃N₅ photoanodes is strongly impacted by the presence of shallow and deep defects within the bandgap. However, the role of such states in defining the stability under operational conditions is not well understood. Here, we use a highly controllable synthesis approach to create homogenous Ta₃N₅ thin films with tailored defect concentrations to establish the relationship between atomic-scale point defects and macroscale stability. Reduced oxygen contents increase long-range structural order but lead to high concentrations of deep-level states, while higher oxygen contents result in reduced structural order but beneficially passivate deep-level defects. Despite the different defect properties, the synthesized photoelectrodes degrade similarly under water oxidation conditions due to formation of a surface oxide layer that blocks interfacial hole injection and accelerates charge recombination. In contrast, under ferrocyanide oxidation conditions, we find that Ta₃N₅ films with high oxygen concentrations exhibit long-term stability, whereas those possessing lower oxygen contents and higher deep-level defect concentrations rapidly degrade. These results indicate that deep-level defects result in rapid trapping of photocarriers and surface oxidation but that shallow oxygen donors can be introduced into Ta₃N₅ to enable kinetic stabilization of the interface.

Microbial U(VI) reduction plays a major role in new bioremediation strategies for radi-onuclide-contaminated environments and can potentially affect the safe disposal of high-level radioactive waste in a deep geological repository. During the process, water-soluble and mobile U(VI) is converted into less-soluble, rather immobile U(IV). This reduction in solubility facilitates a separation of U from contaminated solutions in case of bioremediation efforts and prevents U contaminations of the groundwater in case of final repositories. Desulfitobacterium sp. G1-2, an iron-reducing bacterium, isolated from a bentonite sample, was used to investigate its potential to reduce U(VI) in differ-ent background electrolytes: bicarbonate buffer, where a uranyl(VI)-carbonate com-plex predominates, and synthetic Opalinus Clay pore water, where a uranyl(VI)-lactate complex plays the major role, as confirmed by time-resolved laser-induced fluores-cence spectroscopic measurements. While Desulfitobacterium sp. G1-2 rapidly removed almost all U from the supernatants in bicarbonate buffer, only a low amount of U was removed in Opalinus Clay pore water. UV/Vis measurements suggest a speciation-dependent reduction by the microorganism. Scanning transmission electron microsco-py coupled with energy-dispersive X-ray spectroscopy revealed the formation of two different U-containing nanoparticles inside the cells. In a subsequent step, artificial mul-tispecies bio-aggregates were formed using derivatized polyelectrolytes with cells of Desulfitobacterium sp. G1-2 and Cobetia marina DSM 50416 to assess their potential for U(VI) reduction under aerobic and anaerobic conditions. These findings provide new perspectives on U(VI) reduction by iron-reducing bacteria and contribute to the development of a comprehensive safety concept for high-level radioactive waste repos-itories, as well as to new bioremediation strategies.

A transverse deflecting cavity is being developed for the electron linac ELBE to separate the bunches into two or more beamlines so that multiple user experiments can be carried out simultaneously. A normal conducting double quarter-wave cavity has been designed to deliver a transverse kick of 300 kV when driven by an 800 W solid-state amplifier at 273 MHz. The main challenges in fabrication were machining the complex cavity parts with high precision, pre-tuning the cavity frequency, and the final vacuum brazing within the tolerances, which are described in this paper. The reason for a low intrinsic quality factor measured during the low power test was investigated, and suitable steps were taken to improve the quality factor. The cavity field profiles obtained from the bead-pull measurement matched the simulation results. Further, the cavity was driven up to 1 kW using a modified pick-up antenna, and eventually, vacuum conditioning of the cavity was accomplished. The cavity fulfils the design requirements and is ready for beam tests.

Ute₂ is a spin-triplet superconductor candidate for which high quality samples with long mean free paths have recently become available, enabling quantum oscillation measurements to probe its Fermi surface and effective carrier masses. It has recently been reported that UTe₂ possesses a 3D Fermi surface component [Phys. Rev. Lett. 131, 036501 (2023)]. The distinction between 2D and 3D Fermi surface sections in triplet superconductors can have important implications regarding the topological properties of the superconductivity. Here we report the observation of oscillatory components in the magnetoconductance of UTe₂ at high magnetic fields.We find that these oscillations are well described by quantum interference between quasiparticles traversing semiclassical trajectories spanning magnetic breakdown networks. Our observations are consistent with a quasi-2D model of this material’s Fermi surface based on prior dHvA-effect measurements. Our results strongly indicate that UTe₂—which exhibits a multitude of complex physical phenomena—possesses a remarkably simple Fermi surface consisting exclusively of two quasi-2D cylindrical sections.

Technetium-99 (⁹⁹Tc) is a weak β⁻-emitting radionuclide, whose origin is mainly due to anthropogenic activity since it is a major fission product of uranium-235 and plutonium-239 (ca. 6% yield).[1] Its emission in the environment is of great concern due to its long half-life (2.13 x 10⁵ years). Once released into the environment, it contaminates the water and thus, may enter the food chain. As a result, it can led to cancer and serious health problems due to accumulation in the thyroid gland and gastrointestinal tract.[2] Measures are therefore required to prevent the mobility of Tc (e.g., from a nuclear waste repository) and its subsequent entry into the biosphere. The mobility of Tc is especially dependent on the redox conditions. In aqueous, aerobic, oxidative media, it forms pertechnetate (Tc(VII)O₄⁻), which is highly mobile since it barely interacts with mineral surfaces.[3] On the contrary, under anaerobic, reducing conditions Tc(IV) is dominant, which is less mobile due to the formation of low soluble products (TcO₂.nH₂O and TcS₂), or being immobilized in minerals by surface complexation or mineral incorporation.[4] Therefore, multiple Fe(II)-minerals have been used to study the reductive immobilization of Tc e.g., pyrite (FeS₂).[5] However, the presence of metabolites might alter the interaction of the minerals with Tc due to mineral dissolution, metabolite sorption on the mineral, or the formation of stable, soluble Tc species.
This study investigates the use of pyrite as a reducer and scavenger of Tc(VII) as well as the impact of selected microbial metabolites (acetate, succinate, and desferrioxamine B (DFOB)) on pyrite solubility and technetium retention. A series of batch experiments were conducted to investigate kinetics at different pH (2-12) of several processes: i) the dissolution of pyrite in presence and absence of metabolites, ii) the sorption of metabolites on pyrite, and iii) the interaction of ⁹⁹Tc(VII) and pyrite in presence of metabolites. Iron dissolution has been quantified by inductively coupled plasma mass spectroscopy (ICP-MS), metabolite concentration in solution by high performance liquid chromatography (HPLC), and Tc concentration by liquid scintillation counting (LSC).
Results indicate that whereas acetate and succinate slightly enhance the pyrite solubility, DFOB significantly enhance pyrite dissolution in the entire range of pH values. In addition, the sorption of the metabolites on the mineral surface is negligible.

The study conducted by Rodriguez et al. (2020) demonstrates that the kinetics of Tc removal with pyrite are significantly faster at pH ≥ 5.50, achieving 100% removal within one day. Contrary, at pH levels ≤ 4.50, the removal kinetics are considerably slower, with 98% removal occurring after 35 days. The removal of Tc in presence of metabolites (ternary system) is slightly different. Tc removal kinetics of pyrite are significantly slowed down by acetate at pH 6.6 and succinate at pH 10.5 and 11.5. The Tc removal yield in that case drops down to 85% after 35 days of contact, while the uptake of Tc in absence of acetate or succinate was 100%. The presence of DFOB drastically affect Tc retention, showing a maximum of only 25% Tc uptake at pH 11.5. With regards to the retention mechanisms, pyrite effectively reduces Tc(VII) to Tc(IV) and leads to Tc(IV) sorption on hematite or Tc(IV) incorporation in magnetite in the absence of metabolites[5]. From our macroscopic study of the ternary system, we conclude that the presence of metabolites significantly impacts these immobilization reactions. We hypothesize that the reduction of Tc(VII) to Tc(IV) is still induced by pyrite but the formation of aqueous Tc(IV)-metabolite complexes slows down or hinders the uptake of Tc.

The impact of metabolites is especially remarkable on pyrite solubility and technetium retention. This effect is especially remarkable in the case of DFOB, when its presence induces a higher pyrite solubility and hinders the immobilization of Tc. The findings underscore the importance of considering microbial metabolites in the studies to develop remediation strategies and to assess the safety of nuclear waste repositories.

Future work will focus on studying the mechanism inducing a slower Tc removal kinetics by pyrite, the molecular environment of Tc immobilized on pyrite in presence of metabolites, and the aqueous interaction of Tc with DFOB. Our approach includes the application of scanning electron microscopy, Raman microscopy, in situ and ex situ spectroelectrochemical techniques and X-ray absorption spectroscopy.

The authors acknowledge the German Federal Ministry of Education and Research (BMBF) for the financial support of the NukSiFutur TecRad young investigator group (02NUK072).[6]
References
[1] E. V. Johnstone, M. A. Yates, F. Poineau, A. P. Sattelberger, and K. R. Czerwinski, “Technetium: The First Radioelement on the Periodic Table,” J. Chem. Educ., vol. 94, no. 3, pp. 320–326, Mar. 2017, doi: 10.1021/acs.jchemed.6b00343.
[2] “U.S. Environmental Protection Agency (EPA) (2000) Federal Register: Part 2, 40 CFR Parts 9, 141, and 142, National Primary Drinking Water Regulations: Radionuclides; Final Rule. 815-Z- 00-006.”
[3] K. H. Lieser and Ch. Bauscher, “Technetium in the Hydrosphere and in the Geosphere: Technetium in the Hydrosphere and in the Geosphere,” ract, vol. 42, no. 4, pp. 205–214, Jul. 1987, doi: 10.1524/ract.1987.42.4.205.
[4] C. I. Pearce et al., “Evaluation of materials for iodine and technetium immobilization through sorption and redox-driven processes,” Sci. Total Environ., vol. 716, p. 136167, May 2020, doi: 10.1016/j.scitotenv.2019.136167.
[5] D. M. Rodríguez et al., “New Insights into 99 Tc(VII) Removal by Pyrite: A Spectroscopic Approach,” Environ. Sci. Technol., vol. 54, no. 5, pp. 2678–2687, Mar. 2020, doi: 10.1021/acs.est.9b05341.
[6] “NukSiFutur Young investigators group TecRad: Interactions of technetium with microorganisms, metabolites and at the mineral-water interface – Radioecological considerations. - Helmholtz-Zentrum Dresden-Rossendorf, HZDR.” [Online]. Available: https://www.hzdr.de/db/Cms?pNid=1375

The linear electron accelerator, ELBE (Electron Linac for beams with high Brilliance
and low Emittance) at Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany,
is a versatile machine that drives six distinct secondary particle and radiation sources
used in a wide range of experiments related to health, matter, transmutation, and
accelerator development. The accelerator can efficiently handle 1 mA beam current
at a 13 MHz bunch repetition rate in continuous-wave mode with a maximum beam
energy of 40 MeV. Currently, it is not possible to simultaneously operate more
than one ELBE secondary source. In this work, a suitable beam separator device
for ELBE was developed to overcome the limitation of single beamline operation.
The developed kicker can distribute the bunches from the existing single beam into
two or more beamlines, which will enable the simultaneous operation of multiple
downstream secondary sources, significantly enhancing the accelerator’s capabilities.
The state-of-the-art transverse deflecting structures suitable for beam separation were
reviewed. Subsequently, pulsed magnet, stripline kicker, and radio-frequency (RF)
cavity designs were adapted for the current requirements, and RF cavities were found
suitable. Furthermore, the cavity operating frequency was set to 273 MHz, reducing
both the differential kick voltage error and projected emittance growth and providing
a better field homogeneity. The cavity can be easily integrated into the ELBE’s
existing low-level RF control system. Six deflecting cavity designs were shortlisted,
and the cavity geometries were scaled and adapted to match the requirements. Then,
a cavity design was selected based on lower power loss, peak electric field and surface
power loss density, as well as better field homogeneity.
Subsequent to the cavity design, the cavity components were adapted from the
existing designs. Next, beam loading and multipacting in the cavity were analyzed,
and the effect of higher-order modes on the cavity was studied. A multiphysics
analysis was carried out to aid in the engineering design of the cavity. Thereafter,
the copper cavity parts were machined, and the cavity frequency was pre-tuned
before the final vacuum brazing was performed.
Finally, RF measurements were performed to validate the simulation. A thorough
investigation was carried out to determine the cause of the low intrinsic quality factor of the cavity. Consequently, the quality factor was improved by eliminating the RF
filter present at the vacuum port. A bead-pull measurement setup was built, and
the measured field profiles matched the simulation results. Further, the cavity was
driven up to 1 kW using the modified pick-up antenna, and eventually, the vacuum
conditioning of the cavity was accomplished. The cavity’s performance meets the
design requirements and is ready to be installed in the beamline for further testing.

Graphite oxides (GO) are known to swell in liquid alcohols with significant expansion of c-lattice. However, temperature dependent structural studies of Hummers GO (HGO) swelling have so far been reported only for methanol and ethanol. Here we report in situ synchrotron radiation XRD study of HGO swelling in a set of liquid 1-alcohols (named C1 to C22 according to the number of carbons) as a function of temperature. We report the first observation of swelling transitions never previously observed for HGO in any kind of polar solvents. Enthalpy of swelling transitions and composition of HGO-Cx solid solvates near the point of solvent melting was evaluated by DSC. Swelling transitions from low temperature α-phase to high temperature β-phase are found for HGO in all alcohols in the C10-C22 set, similarly to earlier reported Type II transitions in BGO- long alcohol systems. The transitions correspond to strong change of inter-layer distance correlating with the length of alcohol molecules and change in their orientation from perpendicular to GO planes to parallel to GO (Type II transitions). However, Type I swelling transitions (related to insertion/removal of one layer of alcohol molecules) reported earlier for BGO in alcohols smaller than C10 are not found in HGO. Continuous changes of the d(001) spacing over the temperature interval above the point of alcohol melting are revealed for HGO immersed in all alcohols in the range C1 to C9. Random interstratification of differently solvated inter-layers is the main reason of gradual changes revealed by XRD magnitude of these “diffuse” transitions.

The dipole strength of the nuclide ⁵⁹Co was studied in photon-scattering experiments using bremsstrahlung produced with electron beams of energies of 8.6 and 12.2 MeV at the bremsstrahlung facility γELBE. We identified 130 levels up to an excitation energy of 10.5 MeV. The quasicontin-uum of unresolved transitions was included in the analysis of the spectra and the intensities of branching transitions were estimated on the basis of simulations of statistical γ-ray cascades. The photoabsorption cross section up to the neutron-separation energy was determined and is compared with predictions of the statistical reaction model as well as data for even-mass nuclides in this mass region.

Critical metals like gallium (Ga) and germanium (Ge) hold strategic importance in the development of modern technologies like optoelectronic devices, semiconductors, transistors, light-emitting diodes, and many more​​. The supply of these metals is not assured due to many reasons. Therefore, new sources and efficient recovery techniques need to be identified. Thus, attention should be drawn to sources with very low concentrations of these metals which are usually neglected. The reason for such negligence is the presence of high concentrations of contaminant metals and very low concentrations of these critical metals. Thus, a highly specific, selective, economical, and sustainable process is needed to recover and recycle these metals.

Siderophore assisted technology “GaLIophore” could be a one-point solution. In GaLIophore siderophore Desferroxamine B (DFOB) was used to selectively adsorb Ga from industrial wastewater​​. DFOB is a highly selective molecule that forms a highly stable complex with Ga in an equimolar stoichiometric ratio. It was seen that the complexation of Ga with DFOB was independent of pH and background electrolyte. This technology was then extended to Ge and the complexation of Ge with DFOB was studied. However, with Ge, it was seen that complexation was preferred in acidic pH and was also affected by high-concentration anions like chloride. Moreover, to make the technology economical and sustainable, DFOB was re-generated by the addition of non-specific ligand ethylenediaminetetraacetic acid (EDTA). More than 90% of DFOB were re-generated by the addition of 6 times and 8 times excess of EDTA at pH of 3.5 for Ga and Ge respectively. This led to the recovery of more than 90% for both metals with DFOB complexation at the end of the process. Thus, this technology for the first time demonstrated a solution to recycling these critical metals from low concentrated systems in a sustainable and eco-friendly manner.

In the present study, organic acids - oxalic acid, citric acid, tartaric acid and siderophore Desferrioxamine B were evaluated for their efficiencies to selectively recover Cu from its mold production waste. XRD analysis showed that copper mold production waste mainly consisted of Fe and Cu. The complete dissolution of this waste in aqua regia and subsequent analysis via ICP-MS revealed metal contents of 355.3 mg/g Fe and 293.9 mg/g Cu. Among all the organic acids, citric acid had the highest leaching efficiency (58.5 %) for Fe while leaching <1 % of Cu. Whereas, the leaching of Cu and Fe was poor in oxalic acid medium and Cu leaching was also negligible in tartaric acid medium. Only Fe showed 11.2 % leaching efficiency at 2 mol/L tartaric acid. The step-by-step leaching of production waste with citric acid lead to 100 % leaching of Fe while leaving 93.1 % of Cu with a yield of >99 % in the solid residue in the 4th step. Further, the siderophore Desferrioxamine B could effectively leach Fe (91.2 %) while 21.4 % leaching of Cu in 30 days. The presence of Fe impedes the leaching of Cu from the waste as demonstrated by leaching and DFT calculations due to higher stability of Fe-citrate and Fe-desferrioxamine B complex compared to Cu-organic complexes. This recycling technique described herein is simple, reliable and environmentally friendly for recovery of Cu from copper mold production waste.

The International Atomic Energy Agency (IAEA) in cooperation with the International Society for Tracer and Radiation Applications (ISTRA) promotes the international standardization of basic industrial radiotracer and radiation applications. Experts from many countries analyze existing international standards regarding the necessity of their update or amendment as well as the need for new standards in this field.
In June 2020, a new international standard on “Non-destructive testing - Gamma ray scanning method on process columns” was published as ISO 23159 [1]. About three years before, experts realized the need to standardize this method, which is widely used in petrochemical and chemical plants to identify and locate the cause of malfunction inside various process columns.
In the field of flow rate measurements of fluids in conduits using radioactive tracers, a proposal for a new international standard was prepared in 2021. It united several old national and international standards in this technical field: measurement of water flow in closed conduits (ISO 2975), measurement of gas flow in conduits (ISO 4053) and measurement of fluid flow in closed conduits (ASME MFC-13M-2006). The new international standard with the title “Measurement of Fluid Flow Rate in Closed Conduits – Radioactive Tracer Methods” was published as ISO 24460 in 2023 [2].
Another international standard for determining the concentration or density of suspended and deposited sediment in water bodies by radiometric methods has just been published as ISO 6640 with the title “Measurement of density of water-sediment mixture using radiation transmission method” [3].
In addition, two further international standards using radioactive tracer methods are in preparation. One deals with the leak testing in pressured vessels and underground pipelines, the other with the measurement of residence time distribution and flow characterization using radioactive tracers. These two drafts have already passed the New Work Item Proposal (NWIP) stage. The first one being worked on in ISO Technical Committee 135, Sub Committee 6, Working Group 1 (ISO TC 135/SC 6/WG 1), has just reached the stage as a Draft International Standard (DIS) and is expected to be published as ISO 6366 in September 2024. The second draft is currently being worked on in ISO/TC 030/SC 5/WG 7 and is expected to be published as ISO 25056 in 2026 at the latest.
ISO standards are part of accreditation of radiotracer and radiation applications groups, facilitating the promotion and implementation of these competitive technologies in national, regional and international scale.