Oxidation protection of Mo-Si-B alloys by magnetron-sputtered coatings

Mo-Si-B alloys with melting temperature above 2000 °C are attractive high temperature materials offering significantly enhanced operating temperatures compared to those of the currently used Ni-based superalloys. However, their oxidation behavior is poor at temperatures below 1000 °C, suffering from evaporation of MoO3. Above 1000 °C oxidation is characterized by a transient state showing considerable mass loss followed by a steady state condition with reduced mass change. To mitigate this degradation by oxidation, application of coatings is an appropriate method ensuring the formation of slowly growing protective scales. The presentation summarizes recent results on overlay coatings that were deposited on coupons of a Mo-9Si-8B (in at.%) alloy using magnetron sputtering. A double layer design was applied: a 2 µm thick intermediate Mo5SiB2 layer to prevent interdiffusion and approximately 5 µm thick protective topcoats with different chemical compositions: Mo-45Si-25B, Mo-55Si-10B, Mo-29Si-15B, Mo-48Si-24Al, Mo-71Si-8Al (all in at.%). The amorphous as-deposited coatings were annealed in a vacuum furnace. In the boron containing Mo-Si topcoats, the MoSi2 and MoB phases formed as well as the Mo5Si3 phase in the Mo-29Si-15B coating. In the annealed Mo-48Si-24Al and Mo-71Si-8Al topcoats, the C40-Mo(Si,Al)2 and C11b-MoSi2 phases were observed, respectively. The oxidation behavior of the coated samples was investigated at 800, 1100 and 1300 °C under cyclic condition in laboratory air. The dwell time at high temperature was 10 or 20 h and the samples were tested for up to 10 cycles. Microstructural examinations of the coated samples were carried out using scanning electron microscopy, energy-dispersive X-ray spectroscopy, glow discharge optical emission spectroscopy and X-ray diffraction measurements. Please click Additional Files below to see the full abstract

Advanced Pathogenetic Concepts in T-Cell Prolymphocytic Leukemia and Their Translational Impact

T-cell prolymphocytic leukemia (T-PLL) is the most common mature T-cell leukemia. It is a typically aggressively growing and chemotherapy-resistant malignancy with a poor prognosis. T-PLL cells resemble activated, post-thymic T-lymphocytes with memorytype effector functions. Constitutive transcriptional activation of genes of the T-cell leukemia 1 (TCL1) family based on genomic inversions/translocations is recognized as a key event in T-PLL’s pathogenesis. TCL1’s multiple effector pathways include the enhancement of T-cell receptor (TCR) signals. New molecular dependencies around responses to DNA damage, including repair and apoptosis regulation, as well as alterations of cytokine and non-TCR activation signaling were identified as perturbed hallmark pathways within the past years. We currently witness these vulnerabilities to be interrogated in first pre-clinical concepts and initial clinical testing in relapsed/refractory TPLL patients. We summarize here the current knowledge on the molecular understanding of T-PLL’s pathobiology and critically assess the true translational progress around this to help appraisal by caregivers and patients. Overall, the contemporary concepts on T-PLL’s pathobiology are condensed in a comprehensive mechanistic disease model and promising interventional strategies derived from it are highlighted

Belief Patterns of Student Teachers About the Use of Digital Media in Teaching

Die vorliegende Studie ermittelt durch Clusterung Überzeugungsmuster zukünftiger Lehrpersonen (N = 504) zum Einsatz digitaler Medien im Unterricht. Übergreifend sind positive Überzeugungen zum Medieneinsatz geringer ausgeprägt. Negative erfahren mehr Zustimmung, fallen allerdings zwischen den Mustern divergenter aus. 40 % der Studierenden schätzen den Nutzen für die Unterrichtsentwicklung sowie Motivation und Förderung von Schüler:innen (noch) verhalten positiv ein. Dem stehen zwei Gruppen zukünftiger Lehrpersonen entgegen, deren Überzeugungen zu Überforderung, Zweifeln an der Förderung der ‹richtigen› Kompetenzen und gesundheitlichen Gefährdungen durch digitale Medien stärker ausgeprägt sind. Etwa ein Fünftel von ihnen stimmt solchen negativen Überzeugungen besonders zu. Die Muster und daraus folgende Implikationen werden hinsichtlich der schwierigen Veränderbarkeit von Überzeugungen diskutiert.The present study identifies belief patterns of future teachers (N = 504) about the use of digital media in teaching using cluster analysis. Overall, positive beliefs about the use of media show lower attribute levels. Negative beliefs are more agreed on; nevertheless, the clusters differ considerably. 40 % of the teacher students consider the use of media for innovating teaching, scholars’ motivation and fostering scholars cautiously positive. In contrast, in two other groups of future teachers belief patterns characterized by excessive demands and health risks through the use of media as well as doubts about the promotion of the ‹right› skills are found. About every fifth student teacher particularly agrees with such negative beliefs. The patterns and following implications are discussed with regard to the difficult changeability of beliefs

Mucosal protection by phosphatidylcholine

The colonic mucus serves a first barrier towards invasion of commensal bacteria in stools to prevent inflammation. One essential component of intestinal mucus is phosphatidylcholine (PC) which represents more than 90% of the phospholipids in mucus indicative for a selective transport of PC into this compartment. It is arranged in lamellar structures as surfactant-like particles which provide a hydrophobic surface on top of the hydrated mucus gel to prevent the invasion of bacteria from intestinal lumen. In ulcerative colitis (UC), the mucus PC content is reduced by 70%, irrespective of the state of inflammation. Thus, it could represent an intrinsic primary pathogenetic condition predisposing to bacterial invasion and the precipitation of inflammation. Since PC was shown to be mainly secreted by the ileal mucosa from where it is assumed to move distally to the colon, the PC content along the colonic wall towards the rectum gradually thins, with the least PC content in the rectum. This explains the start of the clinical manifestation of UC in the rectum and the expansion from there to the upper parts of the colon. In three clinical trials, when missing mucus PC in UC was supplemented by an oral, delayed release PC preparation, the inflammation improved and even resolved after a 3-month treatment course. The data indicate the essential role of the mucus PC content for protection against inflammation in colon. Copyright (C) 2012 S. Karger AG, Base

Lifetime of environmental/thermal barrier coatings deposited on an Nb/Nb5Si3- based alloy with FeB-Modified M7Si6-based bond coat

To enhance the performance of aircraft engines, high temperature materials are required being capable to operate at temperatures significantly higher than the temperature limit of about 1150°C approached for Ni-based superalloys currently employed. Nb/Nb5Si3-based composites are promising candidates for turbine engine applications at temperatures up to 1300°C, exhibiting balanced mechanical properties and reduced density compared to Ni-based superalloys [1]. To use these composites in gas turbine combustion atmosphere, environmental/thermal barrier coatings (E/TBCs) are required to protect them against heat, degradation in flowing water vapour and chemical attack of calcium-magnesium-alumino-silicate (CMAS)

Gastrointestinal function in intensive care patients: terminology, definitions and management. Recommendations of the ESICM Working Group on Abdominal Problems

Purpose: Acute gastrointestinal (GI) dysfunction and failure have been increasingly recognized in critically ill patients. The variety of definitions proposed in the past has led to confusion and difficulty in comparing one study to another. An international working group convened to standardize the definitions for acute GI failure and GI symptoms and to review the therapeutic options. Methods: The Working Group on Abdominal Problems (WGAP) of the European Society of Intensive Care Medicine (ESICM) developed the definitions for GI dysfunction in intensive care patients on the basis of the available evidence and current understanding of the pathophysiology. Results: Definitions for acute gastrointestinal injury (AGI) with its four grades of severity, as well as for feeding intolerance syndrome and GI symptoms (e.g. vomiting, diarrhoea, paralysis, high gastric residual volumes) are proposed. AGI is a malfunctioning of the GI tract in intensive care patients due to their acute illness. AGI grade I=increased risk of developing GI dysfunction or failure (a self-limiting condition); AGI grade II=GI dysfunction (a condition that requires interventions); AGI grade III=GI failure (GI function cannot be restored with interventions); AGI grade IV=dramatically manifesting GI failure (a condition that is immediately life-threatening). Current evidence and expert opinions regarding treatment of acute GI dysfunction are provided. Conclusions: State-of-the-art definitions for GI dysfunction with gradation as well as management recommendations are proposed on the basis of current medical evidence and expert opinion. The WGAP recommends using these definitions for clinical and research purpose

Untangling effects of proteins as stabilizers for foam films

Foam film’s properties have a high impact on the properties of the macroscopic foams. This work focusses on protein stabilized foam films. The direct comparison of three different proteins with a concentration normalized to the protein surface enables to distinguish between electrostatic, steric and network stabilization effects. In order to untangle those effects, we study and compare two globular proteins (β − lactoglobulin, BLG, and bovine serum albumin, BSA) and a disordered, flexible protein (whole casein, CN) at low ionic strengths with varying solution pH. Image intensity measurement as a recently developed image analysis method in this field allows to record spatially resolved disjoining pressure isotherms in a Thin Film Pressure Balance (TFPB). This reveals insights into the structure formation in inhomogeneous protein films. As a novel method we introduce tracking inhomogeneities (features) which enables the measurement of interfacial mobility and stiffness of foam films. Around the isoelectric point (IEP), Newton Black Films (NBF) form which are stable for the globular proteins while they are unstable for the disordered flexible one. This difference in film stability is explained by different characteristics of the network structures which is supported by findings in the bulk and at the surface of the respective protein solutions

40 Hz steady-state response in human auditory cortex is shaped by GABAergic neuronal inhibition

The 40 Hz auditory steady-state response (ASSR), an oscillatory brain response to periodically modulated auditory stimuli, is a promising, noninvasive physiological biomarker for schizophrenia and related neuropsychiatric disorders. The 40 Hz ASSR might be amplified by synaptic interactions in cortical circuits, which are, in turn, disturbed in neuropsychiatric disorders. Here, we tested whether the 40 Hz ASSR in the human auditory cortex depends on two key synaptic components of neuronal interactions within cortical circuits: excitation via N-methyl-aspartate glutamate (NMDA) receptors and inhibition via gamma-amino-butyric acid (GABA) receptors. We combined magnetoencephalography (MEG) recordings with placebo-controlled, low-dose pharmacological interventions in the same healthy human participants (13 males, 7 females). All participants exhibited a robust 40 Hz ASSR in auditory cortices, especially in the right hemisphere, under a placebo. The GABAA receptor–agonist lorazepam increased the amplitude of the 40 Hz ASSR, while no effect was detectable under the NMDA blocker memantine. Our findings indicate that the 40 Hz ASSR in the auditory cortex involves synaptic (and likely intracortical) inhibition via the GABAA receptor, thus highlighting its utility as a mechanistic signature of cortical circuit dysfunctions involving GABAergic inhibition

P300 Modulation via Transcranial Alternating Current Stimulation in Adult Attention-Deficit/Hyperactivity Disorder: A Crossover Study

ObjectiveA repeated finding regarding event-related potentials (ERPs) is that patients with ADHD show a reduced P300 amplitude. This raises the question of whether the attention of ADHD patients can be increased by stabilizing the P300. Assuming that the P300 is generated by event-related oscillations (EROs) in the low frequency range (0–8 Hz), one approach to increase the P300 could be to stimulate the patient’s P300 underlying ERO by means of transcranial alternating current stimulation (tACS). The aim of this follow-up study was to investigate this hypothesized mechanism of action in adult ADHD patients.Materials and MethodsUndergoing a crossover design, 20 adult ADHD patients (10 female) received an actual stimulation via tACS on one day and a sham stimulation on another day. Before and after each intervention, EEG characteristics (P300 amplitudes, low frequency power) and attention performances (d2 attention test, visual oddball task (VOT)) were recorded.ResultsElectrophysiological analyses revealed no evidence for an enhanced P300 amplitude or low frequency power increase after actual stimulation compared to sham stimulation. Instead, a significant effect was found for a stronger N700 amplitude increase after actual stimulation compared to sham stimulation. Consistent with the P300 null results, none of the examined neuropsychological performance measures indicated a tACS-induced improvement in attentional ability.ConclusionContrary to a previous study using tACS to modulate the P300 in adult ADHD patients, the current study yields no evidence that tACS can increase the P300 amplitude in adult ADHD patients and that such P300 enhancement can directly improve neuropsychological parameters of attention