Growth mode, magnetic and magneto-optical properties of pulsed-laser-deposited Au/Co/Au(111) trilayers

The growth mode, magnetic and magneto-optical properties of epitaxial Au/Co/Au(111) ultrathin trilayers grown by pulsed-laser deposition (PLD) under ultra-high vacuum are presented. Sapphire wafers buffered with a single-crystalline Mo(110) bilayer were used as substrates. Owing to PLD-induced interfacial intermixing at the lower Co/Au(111) interface, a layer-by-layer growth mode is promoted. Surprisingly, despite this intermixing, ferromagnetic behavior is found at room temperature for coverings starting at 1 atomic layer (AL). The films display perpendicular magnetization with anisotropy constants reduced by 50% compared to TD-grown or electrodeposited films, and with a coercivity more than one order of magnitude lower ($\lesssim$ 5 mT). The magneto-optical (MO) response in the low Co thickness range is dominated by Au/Co interface contributions. For thicknesses starting at 3 AL Co, the MO response has a linear dependence with the Co thickness, indicative of a continuous-film-like MO behavior

Membrane Damage Elicits an Immunomodulatory Program in Staphylococcus aureus

The Staphylococcus aureus HrtAB system is a hemin-regulated ABC transporter composed of an ATPase (HrtA) and a permease (HrtB) that protect S. aureus against hemin toxicity. S. aureus strains lacking hrtA exhibit liver-specific hyper-virulence and upon hemin exposure over-express and secrete immunomodulatory factors that interfere with neutrophil recruitment to the site of infection. It has been proposed that heme accumulation in strains lacking hrtAB is the signal which triggers S. aureus to elaborate this anti-neutrophil response. However, we report here that S. aureus strains expressing catalytically inactive HrtA do not elaborate the same secreted protein profile. This result indicates that the physical absence of HrtA is responsible for the increased expression of immunomodulatory factors, whereas deficiencies in the ATPase activity of HrtA do not contribute to this process. Furthermore, HrtB expression in strains lacking hrtA decreases membrane integrity consistent with dysregulated permease function. Based on these findings, we propose a model whereby hemin-mediated over-expression of HrtB in the absence of HrtA damages the staphylococcal membrane through pore formation. In turn, S. aureus senses this membrane damage, triggering the increased expression of immunomodulatory factors. In support of this model, wildtype S. aureus treated with anti-staphylococcal channel-forming peptides produce a secreted protein profile that mimics the effect of treating ΔhrtA with hemin. These results suggest that S. aureus senses membrane damage and elaborates a gene expression program that protects the organism from the innate immune response of the host

The use of bibliometrics for assessing research : possibilities, limitations and adverse effects

Researchers are used to being evaluated: publications, hiring, tenure and funding decisions are all based on the evaluation of research. Traditionally, this evaluation relied on judgement of peers but, in the light of limited resources and increased bureaucratization of science, peer review is getting more and more replaced or complemented with bibliometric methods. Central to the introduction of bibliometrics in research evaluation was the creation of the Science Citation Index (SCI)in the 1960s, a citation database initially developed for the retrieval of scientific information. Embedded in this database was the Impact Factor, first used as a tool for the selection of journals to cover in the SCI, which then became a synonym for journal quality and academic prestige. Over the last 10 years, this indicator became powerful enough to influence researchers’ publication patterns in so far as it became one of the most important criteria to select a publication venue. Regardless of its many flaws as a journal metric and its inadequacy as a predictor of citations on the paper level, it became the go-to indicator of research quality and was used and misused by authors, editors, publishers and research policy makers alike. The h-index, introduced as an indicator of both output and impact combined in one simple number, has experienced a similar fate, mainly due to simplicity and availability. Despite their massive use, these measures are too simple to capture the complexity and multiple dimensions of research output and impact. This chapter provides an overview of bibliometric methods, from the development of citation indexing as a tool for information retrieval to its application in research evaluation, and discusses their misuse and effects on researchers’ scholarly communication behavior

GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture

Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment

Mechanical loss, creep, diffusion and ionic conductivity of ZrO2-8 mol% Y2O3 polycrystals

Polycrystalline ZrO2-8 mol%Y2O3 was investigated by combining several experimental techniques on identical materials sintered out of the same high purity powder. The mechanical loss spectrum (damping and elastic modulus) was measured in a large frequency and temperature range (10(-2)Hz-1.5kHz; -150 to 1400 degrees C). Damping due to point defect relaxation at low temperature and to viscoelastic relaxation at high temperature was revealed. The creep resistance was investigated with four-point bending tests (stress and temperature ranges: 20-75 MPa, 1100-1290 degrees C), indicating Nabarro-Herring creep as the main rate-controlling mechanism. Both viscoelastic deformation and creep seem to be controlled by cation diffusion. Measurements of the Zr-96 tracer diffusivity by secondary ion mass spectrometry at 1125-1460 degrees C yielded an activation enthalpy of 460 kJ/mol. Close values were obtained for creep (440 kJ/mol) and viscoelastic relaxation (530 kJ/mol). Finally, the ionic DC-conductivity of these electrolytes was measured with high accuracy in the range 300-1250 degrees C. (C) 2000 Elsevier Science Ltd. All rights reserved

Amorphe Mischhalbleiter auf der Basis von Silizium fuer Tandemsolarzellen Schlussbericht

SIGLETIB Hannover: FR 2241(Schl) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman