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

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)

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

Non-small cell lung cancer cells and concomitant cancer therapy induce a resistance-promoting phenotype of tumor-associated mesenchymal stem cells

IntroductionThe tumor microenvironment gained attraction over the last decades as stromal cells significantly impact on tumor development, progression and metastasis, and immune evasion as well as on cancer therapy resistance. We previously reported that lung-resident mesenchymal stem cells (MSCs) were mobilized and activated in non-small cell lung cancer (NSCLC) progression and could even mediate radiation resistance in co-cultured NSCLC cells.MethodsWe investigated how MSCs were affected by NSCLC cells in combination with cancer (radiation) therapy in indirect co-cultures using tumor-conditioned medium and Transwells or direct three-dimensional NSCLC–MSC spheroid co-cultures in order to unravel the resistance-mediating action of tumor-associated MSCs.ResultsAlthough no obvious phenotypic and functional alterations in MSCs following NSCLC co-culture could be observed, MSC senescence was induced following co-applied radiotherapy (RT). Global gene expression profiling, in combination with gene set enrichment analysis upon treatment, was used to confirm the senescent phenotype of irradiated MSC and to reveal relevant senescence-associated secretory phenotype (SASP) factors that could meditate NSCLC RT resistance. We identified senescent tumor-associated MSC-derived serine proteinase inhibitor (serpin) E1/PAI1 as potential SASP factor mediating NSCLC progression and RT resistance.DiscussionSpecified intra-tumor–stroma interactions and cell type-specific pro-tumorigenic functions could not only improve lung cancer classification but could even be used for a more precise profiling of individual patients, finally paving an additional way for the discovery of potential drug targets for NSCLC patients

Multimodal Virtual Reality-Based Assessment of Adult ADHD : A Feasibility Study in Healthy Subjects

Neuropsychological assessments are often surprisingly inaccurate in mapping clinically-reported attention-deficit hyperactivity disorder (ADHD) symptoms, presumably due to their low ecological validity. Virtual reality (VR) might offer a potential solution for this problem, given its capability to generate standardized and yet highly realistic virtual environments. As the first adaptation of existing virtual classroom scenarios to an adult population, we developed a Virtual Seminar Room (VSR) for multimodal characterization of ADHD symptoms. To test its feasibility, N= 35 healthy participants were immersed into the VSR via a head-mounted display and carried out a VR-embedded continuous performance task (CPT) under varying levels of distractions in two experimental blocks (24 min each). CPT performance, electroencephalography (EEG) measures, and head movements (actigraphy) were simultaneously recorded and analyzed offline. Although CPT performance remained constant throughout the task, head movements increased significantly from Block 1 to Block 2. In addition, EEG theta (4–7 Hz) and beta (13–30 Hz) power was higher during Block 1 than Block 2, and during distractor-present than distractor-absent phases. Moreover, P300 amplitudes were higher during Block 1 than Block 2, and P300 latencies were prolonged in distractor-absent compared with distractor-present phases. Although the paradigm awaits further improvements, this study confirms the general feasibility of the VSR and provides a first step toward a multimodal, ecologically valid, and reliable VR-based adult ADHD assessment

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