Mouse invariant chain γ exhibits structural homology to both polymorphic subunits of the α,β-core complex of I-Ak antigens

AbstractThe 3 major constituents of the I-Ak subregion-associated complex α, β and γ were obtained from splenocytes in homogeneous form by differential isolation methods. α, β and γ were compared on the primary structural level by enzymatic fragmentation procedures and tryptic peptide map analysis of radiolabeled proteins. The data indicate that the invariant chain γ exhibits extensive structural homology to the polymorphic β-light and the α-heavy chain. Thus, although not being encoded within the MHC γ appears to belong structurally to the MHC-encoded class II proteins

Generation of Pure-State Single-Photon Wavepackets by Conditional Preparation Based on Spontaneous Parametric Downconversion

We study the conditional preparation of single photons based on parametric downconversion, where the detection of one photon from a given pair heralds the existence of a single photon in the conjugate mode. We derive conditions on the modal characteristics of the photon pairs, which ensure that the conditionally prepared single photons are quantum-mechanically pure. We propose specific experimental techniques that yield photon pairs ideally suited for single-photon conditional preparation.Comment: 14 pages, 6 figure

BiasBed -- Rigorous Texture Bias Evaluation

The well-documented presence of texture bias in modern convolutional neural networks has led to a plethora of algorithms that promote an emphasis on shape cues, often to support generalization to new domains. Yet, common datasets, benchmarks and general model selection strategies are missing, and there is no agreed, rigorous evaluation protocol. In this paper, we investigate difficulties and limitations when training networks with reduced texture bias. In particular, we also show that proper evaluation and meaningful comparisons between methods are not trivial. We introduce BiasBed, a testbed for texture- and style-biased training, including multiple datasets and a range of existing algorithms. It comes with an extensive evaluation protocol that includes rigorous hypothesis testing to gauge the significance of the results, despite the considerable training instability of some style bias methods. Our extensive experiments, shed new light on the need for careful, statistically founded evaluation protocols for style bias (and beyond). E.g., we find that some algorithms proposed in the literature do not significantly mitigate the impact of style bias at all. With the release of BiasBed, we hope to foster a common understanding of consistent and meaningful comparisons, and consequently faster progress towards learning methods free of texture bias. Code is available at https://github.com/D1noFuzi/BiasBe

Mast Cells Control Neutrophil Recruitment during T Cell–Mediated Delayed-Type Hypersensitivity Reactions through Tumor Necrosis Factor and Macrophage Inflammatory Protein 2

Polymorphonuclear leukocytes (PMNs) characterize the pathology of T cell–mediated autoimmune diseases and delayed-type hypersensitivity reactions (DTHRs) in the skin, joints, and gut, but are absent in T cell–mediated autoimmune diseases of the brain or pancreas. All of these reactions are mediated by interferon γ–producing type 1 T cells and produce a similar pattern of cytokines. Thus, the cells and mediators responsible for the PMN recruitment into skin, joints, or gut during DTHRs remain unknown. Analyzing hapten-induced DTHRs of the skin, we found that mast cells determine the T cell–dependent PMN recruitment through two mediators, tumor necrosis factor (TNF) and the CXC chemokine macrophage inflammatory protein 2 (MIP-2), the functional analogue of human interleukin 8. Extractable MIP-2 protein was abundant during DTHRs in and around mast cells of wild-type (WT) mice but absent in mast cell–deficient WBB6F1-KitW/KitW-v (KitW/KitW-v) mice. T cell–dependent PMN recruitment was reduced >60% by anti–MIP-2 antibodies and >80% in mast cell–deficient KitW/KitW-v mice. Mast cells from WT mice efficiently restored DTHRs and MIP-2–dependent PMN recruitment in KitW/KitW-v mice, whereas mast cells from TNF−/− mice did not. Thus, mast cell–derived TNF and MIP-2 ultimately determine the pattern of infiltrating cells during T cell–mediated DTHRs

Low-Temperature Phase of the Cd2_2Re2_2O7_7 Superconductor: Ab initio Phonon Calculations and Raman Scattering

Using an {\it ab initio} approach, we report a phonon soft mode in the tetragonal structure described by the space group $I4_{1}22$ of the $1$ K $5d$ superconductor Cd$_2$Re$_2$O$_7$. It induces an orthorhombic distortion to a crystal structure described by the space group $F222$ which hosts the superconducting state. This new phase has a lower total energy than the other known crystal structures of Cd$_2$Re$_2$O$_7$. Comprehensive temperature dependent Raman scattering experiments on isotope enriched samples, $^{116}$Cd$_2$Re$_2{^{18}}$O$_7$, not only confirm the already known structural phase transitions but also allow us to identify a new characteristic temperature regime around $\sim 80$ K, below which the Raman spectra undergo remarkable changes with the development of several sharp modes and mode splitting. Together with the results of the \textit{ab initio} phonon calculations we take these observations as strong evidence for another phase transition to a novel low-temperature crystal structure of Cd$_2$Re$_2$O$_7$.Comment: 7 pages, 8 figure

Leptospira spp. strain identification by MALDI TOF MS is an equivalent tool to 16S rRNA gene sequencing and multi locus sequence typing (MLST)

Background: In this study mass spectrometry was used for evaluating extracted leptospiral protein samples and results were compared with molecular typing methods. For this, an extraction protocol for Leptospira spp. was independently established in two separate laboratories. Reference spectra were created with 28 leptospiral strains, including pathogenic, non-pathogenic and intermediate strains. This set of spectra was then evaluated on the basis of measurements with well-defined, cultured leptospiral strains and with 16 field isolates of veterinary or human origin. To verify discriminating peaks for the applied pathogenic strains, statistical analysis of the protein spectra was performed using the software tool ClinProTools. In addition, a dendrogram of the reference spectra was compared with phylogenetic trees of the 16S rRNA gene sequences and multi locus sequence typing (MLST) analysis. Results: Defined and reproducible protein spectra using MALDI-TOF MS were obtained for all leptospiral strains. Evaluation of the newly-built reference spectra database allowed reproducible identification at the species level for the defined leptospiral strains and the field isolates. Statistical analysis of three pathogenic genomospecies revealed peak differences at the species level and for certain serovars analyzed in this study. Specific peak patterns were reproducibly detected for the serovars Tarassovi, Saxkoebing, Pomona, Copenhageni, Australis, Icterohaemorrhagiae and Grippotyphosa. Analysis of the dendrograms of the MLST data, the 16S rRNA sequencing, and the MALDI-TOF MS reference spectra showed comparable clustering. Conclusions: MALDI-TOF MS analysis is a fast and reliable method for species identification, although Leptospira organisms need to be produced in a time-consuming culture process. All leptospiral strains were identified, at least at the species level, using our described extraction protocol. Statistical analysis of the three genomospecies L. borgpetersenii, L. interrogans and L. kirschneri revealed distinctive, reproducible differentiating peaks for seven leptospiral strains which represent seven serovars. Results obtained by MALDI-TOF MS were confirmed by MLST and 16S rRNA gene sequencing

Entwicklung und Validierung eines eID-Ökosystem-Modells – Fallbeispiel Schweiz

Gegenstand des vorliegenden Beitrags ist die Entwicklung eines soziotechnischen Öko-system-Modells für elektronische Identitäten (eID), das national und international anwendbar ist. Im vorliegenden Beitrag wird die Frage beantwortet, wie der Nutzungserfolg einer eID erreicht werden kann. Diese Frage wird vor dem Hintergrund gestellt, dass nationale eID-Lösungen etwa in der EU oder auf anderen Kontinenten teilweise nicht den gewünschten Erfolg bringen [CD11], [Ku10]. Die Entwicklung des eID-Ökosystem-Modells erfolgte mit dem Ziel der Klärung der Fördermaßnahmen und der Konkretisierung der Zusammenarbeit von Staat und Privatwirtschaft. Ein weiteres Ziel war, das Modell als geeignete Basis für die sachlich differenzierte Strategie-Diskussion zur eID-Einführung in der Schweiz zu verwenden. Eine wesentliche Erkenntnis aus der Forschungs- und Entwicklungsperspektive des Modellbaus eines eID-Ökosystems ist, dass der organisatorische Rahmen und die konkrete Ausgestaltung der Vertrauensdienste wesentlich ent-scheidender sind als das rein technische Design von eID-Lösungen