The breakdown flash of Silicon Avalance Photodiodes - backdoor for eavesdropper attacks?

Silicon avalanche photodiodes are the most sensitive photodetectors in the visible to near infrared region. However, when they are used for single photon detection in a Geiger mode, they are known to emit light on the controlled breakdown used to detect a photoelectron. This fluorescence light might have serious impacts on experimental applications like quantum cryptography or single-particle spectroscopy. We characterized the fluorescence behaviour of silicon avalanche photodiodes in the experimentally simple passive quenching configuration and discuss implications for their use in quantum cryptography systems.Comment: 9 pages, 6 figures, submitted to J. Mod. Optic

Mycotoxin occurrence in maize silage : a neglected risk for bovine gut health?

Forages are important components of dairy cattle rations but might harbor a plethora of mycotoxins. Ruminants are considered to be less susceptible to the adverse health effects of mycotoxins, mainly because the ruminal microflora degrades certain mycotoxins. Yet, impairment of the ruminal degradation capacity or high ruminal stability of toxins can entail that the intestinal epithelium is exposed to significant mycotoxin amounts. The aims of our study were to assess (i) the mycotoxin occurrence in maize silage and (ii) the cytotoxicity of relevant mycotoxins on bovine intestinal cells. In total, 158 maize silage samples were collected from European dairy cattle farms. LC-MS/MS-based analysis of 61 mycotoxins revealed the presence of emerging mycotoxins (e.g., emodin, culmorin, enniatin B1, enniatin B, and beauvericin) in more than 70% of samples. Among the regulated mycotoxins, deoxynivalenol and zearalenone were most frequently detected (67.7%). Overall, 87% of maize silages contained more than five mycotoxins. Using an in vitro model with calf small intestinal epithelial cells B, the cytotoxicity of deoxynivalenol, nivalenol, fumonisin B1 and enniatin B was evaluated (0-200 mu M). Absolute IC50 values varied in dependence of employed assay and were 1.2-3.6 mu M, 0.8-1.0 mu M, 8.6-18.3 mu M, and 4.0-6.7 mu M for deoxynivalenol, nivalenol, fumonisin B1, and enniatin B, respectively. Results highlight the potential relevance of mycotoxins for bovine gut health, a previously neglected target in ruminants

Sec1/Munc18 Protein Stabilizes Fusion-Competent Syntaxin for Membrane Fusion in Arabidopsis Cytokinesis

SummaryIntracellular membrane fusion requires complexes of syntaxins with other SNARE proteins and regulatory Sec1/Munc18 (SM) proteins. In membrane fusion mediating, e.g., neurotransmitter release or glucose-stimulated insulin secretion in mammals, SM proteins preferentially interact with the inactive closed, rather than the active open, conformation of syntaxin or with the assembled SNARE complex. Other membrane fusion processes such as vacuolar fusion in yeast involve like membranes carrying cis-SNARE complexes, and the role of SM protein is unknown. We investigated syntaxin-SM protein interaction in membrane fusion of Arabidopsis cytokinesis, which involves cytokinesis-specific syntaxin KNOLLE and SM protein KEULE. KEULE interacted with an open conformation of KNOLLE that complemented both knolle and keule mutants. This interaction occurred at the cell division plane and required the KNOLLE linker sequence between helix Hc and SNARE domain. Our results suggest that in cytokinesis, SM protein stabilizes the fusion-competent open form of syntaxin, thereby promoting trans-SNARE complex formation

Metal biogeochemistry in constructed wetlands based on fluviatile sand and zeolite- and clinopyroxene-dominated lava sand

For the first time, speciation of Fe, Mn, Zn, Ni, Cu and Pb was determined along the profiles of 8 constructed wetlands (CWs) consisting of fluviatile sand (Fluv), clinopyroxene-dominated lava sand (Cl-LS) and zeolite-dominated lava sand (Ze-LS), aiming at quantifying metal behaviour in CWs and the impact caused by different filter materials. With the exception of Mn, which underwent reductive dissolution, CWs were sinks for the studied metals. Metal accumulation rates differed in the following order: Ze-LS ≥ Cl-LS > Fluv CWs, reflecting the highest metal adsorption capacity and the lowest hydraulic conductivity of Ze-LS. Sequential extraction data indicated the highest metal mobility (readily mobilised and adsorbed fractions summing up to ~60%) in Fluv CWs, implying a higher risk of metal release into adjacent environments if Fluv from CWs will be improperly disposed after usage. Zinc and Ni were transported into the deeper CW layers to a larger extent than Cu and Pb, reflecting adsorption affinity to all filter materials in the order of Pb > Cu > Zn > Ni. Therefore, understanding metal speciation and mobility in such materials is crucial when they are considered for application as filters in CWs

A Survey on Dataset Distillation: Approaches, Applications and Future Directions

Dataset distillation is attracting more attention in machine learning as training sets continue to grow and the cost of training state-of-the-art models becomes increasingly high. By synthesizing datasets with high information density, dataset distillation offers a range of potential applications, including support for continual learning, neural architecture search, and privacy protection. Despite recent advances, we lack a holistic understanding of the approaches and applications. Our survey aims to bridge this gap by first proposing a taxonomy of dataset distillation, characterizing existing approaches, and then systematically reviewing the data modalities, and related applications. In addition, we summarize the challenges and discuss future directions for this field of research

A Novel Bacterial Artificial Chromosome-Transgenic Podoplanin–Cre Mouse Targets Lymphoid Organ Stromal Cells in vivo

Stromal cells provide the structural foundation of secondary lymphoid organs (SLOs), and regulate leukocyte access and cell migration within the different compartments of spleen and lymph nodes (LNs). Furthermore, several stromal cell subsets have been implied in shaping of T cell responses through direct presentation of antigen. Despite significant gain of knowledge on the biology of different SLO-resident stromal cell subsets, their molecular and functional characterization has remained incomplete. To address this need, we have generated a bacterial artificial chromosome-transgenic mouse model that utilizes the podoplanin (pdpn) promoter to express the Cre-recombinase exclusively in stromal cells of SLOs. The characterization of the Pdpn–Cre mouse revealed transgene expression in subsets of fibroblastic reticular cells and lymphatic endothelial cells in LNs. Furthermore, the transgene facilitated the identification of a novel splenic perivascular stromal cell subpopulation that forms web-like structures around central arterioles. Assessment of the in vivo antigen expression in the genetically tagged stromal cells in Pdpn–Cre mice revealed activation of both MHC I and II-restricted TCR transgenic T cells. Taken together, stromal pdpn–Cre expression is well-suited to characterize the phenotype and to dissect the function of lymphoid organ stromal cells

Project Briefing #1: Structure of Project 1 within the Cluster Net-Zero-2050

Clarification of the work focus and the connection of the different elements of the Helmholtz Climate Initiative‘s Cluster I Net-Zero-205

Stereochemistry of phase-1 metabolites of mephedrone determines their effectiveness as releasers at the serotonin transporter

Mephedrone (4-methyl-N-methylcathinone) is a psychostimulant that promotes release of monoamines via the high affinity transporters for dopamine (DAT), norepinephrine (NET) and serotonin (SERT). Metabolic breakdown of mephedrone results in bioactive metabolites that act as substrate-type releasers at monoamine transporters and stereospecific metabolism of mephedrone has been reported. This study compared the effects of the enantiomers of the phase-1 metabolites nor-mephedrone, 4-hydroxytolyl-mephedrone (4-OH-mephedrone) and dihydro-mephedrone on (i) DAT, NET and SERT mediated substrate fluxes, (ii) determined their binding affinities towards a battery of monoamine receptors and (iii) examined the relative abundance of the enantiomers in human urine. Each of the enantiomers tested inhibited uptake mediated by DAT, NET and SERT. No marked differences were detected at DAT and NET. However, at SERT, the S-enantiomers of nor-mephedrone and 4-OH-mephedrone were several times more potent than the corresponding R-enantiomers. Moreover, the R-enantiomers were markedly less effective as releasers at SERT. S-nor-mephedrone displayed moderate affinities towards human alpha; 1A; , human 5-HT; 2A; and rat and mouse trace amine-associated receptor 1. These results demonstrate that stereochemistry dictates the pharmacodynamics of the phase-1 metabolites of mephedrone at SERT, but not at DAT and NET, which manifests in marked differences in their relative potencies, i.e. DAT/SERT ratios. Chiral analysis of urine samples demonstrated that nor-mephedrone predominantly exists as the S-enantiomer. Given the asymmetric abundance of the enantiomers in biological samples, these findings may add to our understanding of the subjective effects of administered mephedrone, which indicate pronounced effects on the serotonergic system