Fachhochschule Kiel

Wet-chemical processing of metals, for example, galvanic deposition, etching, and nanoparticle synthesis, usually requires complexing agents. In particular, for noble metal processing, anionic complexing species, such as halides or sulfide are indispensable. While it is known that these species strongly adsorb on metal surfaces and affect metal nucleation and growth, the detailed role of these anions in the underlying atomistic processes is less clear. Often, it is assumed that surface complexes are involved, but experimental evidence for the latter is still lacking. Here, we present direct in situ video-rate scanning tunneling microscopy observations of gold-bromide and gold-sulfur surface complexes on Au(100) electrodes. Based on the intramolecular resolution images obtained in these studies, these species can be assigned to a dimeric planar and a linear complex. Once formed, the surfaces complexes are stable even at rather negative potentials and diffuse as molecular species on the Ausurface.

In 2022, Hanahan integrated polymorphic microbiomes to the hallmarks of cancer, resulting in 14 overarching features that are considered fundamental to initiation and progression of cancers. It is well acknowledged that genomic instability/genetic alterations together with tumor-associated inflammation are so called "enabling hallmarks" as they drive the acquisition of the other traits. The microbiome is a key component of the inflammatory tumor stroma. Pancreatic ductal adenocarcinoma (PDAC) in particular is characterized by a pronounced stromal compartment whose role in the acquisition of malignant properties is well documented. Recent studies indicate massive alterations of the microbiome in PDAC tissues compared to healthy pancreas or precursor lesions. However, the mechanistic role of the PDAC-associated microbiome, its influence on the hallmarks of cancer, and how this relates to PDAC malignancy remain poorly understood. This raises the question of whether the tumor-associated microbiome through its direct influence on PDAC cells, their precursors, and the surrounding non-neoplastic cells promotes the acquisition of other hallmarks that drive PDAC development and progression. This perspective article outlines the current knowledge of the impact of the PDAC-associated microbiome on the hallmarks of cancer in PDAC. These current findings support the altered microbiome as a third enabling hallmark of PDAC and emphasize that further mechanistic studies are urgently needed to further substantiate its fundamental importance for this tumor entity. This knowledge will provide the basis for clinical translation to develop more effective therapeutic approaches for PDAC. The intratumoral microbiome in PDAC exhibits numerous interactions with the hallmarks of cancer. Hallmarks indicated in blue have demonstrated interactions with the microbiome, while others still remain underexplored. These extensive interactions substantiate the role of the intratumoral microbiome in PDAC as an enabling hallmark, underlining its potential as a therapeutic target. Partially created with biorender.com.

Flame aerosol reactors are the preferred industrial method for producing nanostructured materials such as carbon black, fumed silica, and titania pigments. These reactors enable large-scale, reproducible nanopowder synthesis. The field has been revolutionized by the integration of two-phase atomization nozzles in flame spray pyrolysis (FSP) reactors; these reactors enable the processing of virtually any precursor via liquid dissolution and greatly surpasses the limitations of traditional vapor-based approaches. Most importantly, FSP is no longer a "black box"; recent advances in theory and experiments have provided fundamental insights into particle growth dynamics and enabled the precise control over nanoparticle properties with low batch-to-batch variation. This understanding is crucial for biomedical applications, where reproducibility and functional performance are vital. Here, we review the latest developments in flame-made nanoparticles for biomedical applications, with a focus on FSP reactor engineering, surface property control, and direct integration into medical devices. We discuss the theoretical framework behind reactor design and its impact on material performance. While FSP has demonstrated remarkable versatility for medical nanomaterials, addressing challenges such as good manufacturing practice (GMP) compliance, in vivo safety, and clinical translation will be essential for its widespread adoption in biomedicine. • Flame spray pyrolysis enables scalable, continuous, and reproducible synthesis of nanomaterials for biomedical use. • Reactor design tuning in FSP enables mixed oxides, doped systems, core-shell nanoparticles, and porous coatings. • Case studies show FSP nanomaterials for antibacterial devices, drug delivery, biosensing, and stimuli-responsive systems. • Enclosed FSP with vapor precursors enables coated non-oxides, supporting precise functionalization for biomedical uses. • A safe-by-design framework links FSP processing to toxicity and supports GMP- and QbD-aligned clinical translation.

Quantum Key Distribution (QKD) networks guarantee information-theoretical security of exchanged keys, but key rates are still limited. This makes efficient and adaptive routing a critical challenge, especially in meshed topologies without quantum repeaters. Conventional shortest path routing approaches struggle to cope with dynamic key store filling levels and changes in network topologies, which leads to load imbalance and blocked connections. In this work, we propose an adaptive routing framework based on Deep Reinforcement Learning (DRL) for hop-wise end-to-end routing in unknown meshed QKD networks. The agent leverages Graph Attention Networks (GATs) to process the network states of varying topologies, enabling generalization across previously unseen meshed networks without topology-specific retraining. The agent is trained on random graphs with 10 to 20 nodes and learns a routing policy that explicitly balances key consumption across the network by utilizing a reward function that is based on the entropy of key store filling levels. We evaluate the proposed approach on the 14-node NSFNET topology under time-varying traffic demands. Simulation results demonstrate that the DRL-based routing significantly outperforms hop-based and weighted shortest path benchmarks, achieving up to a 18.7% increase in mean key store filling levels while completely avoiding key store depletion. These results highlight the potential of graph-based DRL methods for scalable, adaptive, and resource-efficient routing in future QKD networks.

Whole-room indirect calorimeters (WRICs) measure respiratory exchange, energy expenditure, and macronutrient oxidation. The thermic effect of food (TEF) that occurs after food intake due to digestion, absorption, and storage of nutrients is an important component of daily energy expenditure, but difficult to quantify using metabolic carts. This study evaluated the validity and reproducibility of a 7209 L WRIC for TEF measurement. Technical validation was performed with 7-h propane combustion tests (n = 5), and biological reproducibility was tested in 10 healthy subjects (6 men, mean age 33.5 ± 10.3 years) in replicate 7-h measurements, after a 3-day run-in protocol. Coefficient of variation (CV) and intraclass correlation coefficient (ICC) were calculated for ventilation rates of O2 (VO2) and CO2 (VCO2), respiratory exchange ratio (RER; VCO2/VO2), postprandial energy expenditure, and TEF. Technical validation showed good validity with CVs ranging from 0.23% for RER to 1.74% for energy expenditure. For biological reproducibility, CVs were 3.42%, 1.97%, 2.58%, 3.07%, and 27.48% for VO2, VCO2, postprandial RER, postprandial energy expenditure, and TEF, respectively. ICCs were excellent for VO2 (96%), VCO2 (98%), and postprandial energy expenditure (96%), but poor for TEF (24%). In conclusion, the 7209 L WRIC is technically valid and reproducible for ventilation rates and postprandial energy expenditure but showed lower reproducibility for TEF.

ABSTRACT We benchmark nonequilibrium Green's function (NEGF) approaches for interaction quenches in the half‐filled Fermi–Hubbard model in one and two dimensions. We compare fully self‐consistent two‐time Kadanoff–Baym equations (KBE), the generalized Kadanoff–Baym ansatz (GKBA), and the recently developed NEGF‐based quantum fluctuations approach (NEGF‐QF) with second‐order Born (2B) and GW self‐energies. As references, we use DMRG in 1D and time‐dependent perturbation theory at weak coupling. While all methods reproduce the early‐time build‐up of correlations (prethermalization), different deficiencies emerge during the slower relaxation in the long‐time limit: KBE shows overdamped oscillations, GKBA exhibits a negative overshoot of the Fermi‐surface jump, and NEGF‐QF develops a prethermalization plateau with delayed relaxation. In 1D, we find that GKBA + 2B agrees best with DMRG across the explored parameter range, while QF + GW deviates the most, consistent with its reduced self‐consistency. In 2D, all approaches correctly capture the momentum‐dependence of the relaxation dynamics.

Lysozymes are an essential part of immunity and nutrition in metazoans, degrading bacterial cell walls via the hydrolysis of peptidoglycan. Although various lysozymes have been reported for higher animals, the origin of animal lysozymes remains elusive as they seem to be lacking in all early branching phyla. In this study, we investigated a putative goose-type lysozyme (PLys, glycoside hydrolase family 23, GH23) of the placozoan Trichoplax sp. H2. We show that PLys is highly active and primarily produced by cells of the placozoan ventral epithelium. PLys contains a non-conserved cysteine-rich domain N-terminal of the GH23 lysozyme domain, which stabilizes the protein and is truncated during maturation. Using a pH-sensitive fluorescence reporter, we show that Trichoplax sp. H2 acidifies its temporary feeding grooves pulsatively during digestive events close to the optimum pH for PLys activity. To elucidate the evolutionary origin of the metazoan GH23 lysozyme family, we applied structure-based phylogenetics to show that the metazoan g-type GH23 lysozymes originated from a horizontal gene transfer event from bacteria to an early pre-bilaterian ancestor. GH23 lysozymes have then been retained and expanded in many phyla acting as first animal lysozyme and a key component in the antibacterial arsenal since early animal evolution.

ABSTRACT Photocatalytic reactions hold great promise for using the abundant solar energy for green energy production via water splitting to gain as well as purifying air from pathogens or waste water from organic pollutants. To initiate these reactions using visible light, a catalytic material is required, often based on compounds of one or more oxide semiconductors, which necessitates the control of material production and the designed architecture with respect to the targeted application. In this contribution, we demonstrate a wet chemical synthesis approach to produce a highly macroporous 3D network structure of oxide semiconductors /(Zn) which is hierarchically designed by interconnecting hollow microscale tetrapodal structures with nanoscale functionalization using a core/shell geometry. Transmission electron microscopy was used to identify the present crystalline structures and chemical properties of the components before and after annealing. Before annealing, a variation of the oxidation state is present in the nanocrystalline component, while during further oxidation the formation of a ternary particle network composed of heterojunctions between , rutile and crystalline particles is evidenced. Producing such a combination of materials on a rigid and macroporous framework could show great potential as a catalyst for liquid‐ or gas phase applications.

ABSTRACTUnderstanding the nested distribution patterns is ecologically crucial for revealing river ecosystem heterogeneity and biodiversity maintenance. However, there is a notable research gap in understanding the nested patterns of river algae under the influence of small hydropower plants (SHPs), particularly in the context of ecological flow regulation. This study focused on the Oujiang river basin, where SHPs are widely distributed, exploring the effects of SHPs on the nestedness (NODF) of river algae under ecological flow and intensive development conditions. By calculating NODF, functional nestedness (traitNODF), phylogenetic nestedness (phyloNODF), and environmental nestedness (envNODF) for different river sections, the results indicated: (1) the entire basin and its different river sections exhibited significant nestedness; (2) the reservoir and dewatering sections were more strongly affected by SHPs, with traitNODF and phyloNODF remaining unchanged despite some environmental factors; (3) species with weaker attachment abilities and larger cell sizes tended to inhabit more unique habitats, particularly in reservoirs. These findings demonstrate that SHPs reshape algal communities primarily through environmental filtering, with reservoirs experiencing the strongest habitat modification. The study highlights the need for segment‐specific management strategies in SHPs development to balance water use and ecosystem conservation. Future work should further explore nestedness–ecosystem stability relationships under human disturbances.