75 research outputs found
Superelasticity in high strength heterophase single crystals of Ni51.0Ti36.5Hf12.5 alloy
The effect of precipitated disperse H-phase particles on the thermoelastic B2–B19′ martensitic transformation (MT) under compressive load has been studied on [001]-, [236]-, and [223]-oriented single crystals of Ni51.0Ti36.5Hf12.5 (at %) alloy in the initial (as-grown) state. It is established that, in Ni51.0Ti36.5Hf12.5 single crystals containing disperse H-phase particles with dimensions within 125–150 nm at a volume fraction of ~30%, neither the critical stresses of martensite formation nor superelasticity strain depend on the orientation. Fully reversible B2–B19′ MTs in Ni51.0Ti36.5Hf12.5 single crystals have been observed in tests at external axial stresses up to 1700 MPa and temperatures up to Tt ~ 373 K
Computational modelling of full interaction between crystal plasticity and oxygen diffusion at a crack tip
Oxidation-promoted crack growth, one of the major concerns for nickel-based superalloys, is closely linked to the diffusion of oxygen into the crack tip. The phenomenon is still not well understood yet, especially the full interaction between oxygen diffusion and severe near-tip mechanical deformation. This work aimed at the development of a robust numerical strategy to model the full coupling of crystal plasticity and oxygen diffusion in a single crystal nickel-based superalloy. In order to accomplish this, finite element package ABAQUS is used as a platform to develop a series of user-defined subroutines to model the fully coupled process of deformation and diffusion. The formulation allowed easy incorporation of nonlinear material behaviour, various loading conditions and arbitrary model geometries. Using this method, finite element analyses of oxygen diffusion, coupled with crystal plastic deformation, were carried out to simulate oxygen penetration at a crack tip and associated change of near-tip stress field, which has significance in understanding crack growth acceleration in oxidation environment. Based on fully coupled diffusion-deformation analyses, a case study was carried out to predict crack growth rate in oxidation environment and under dwell-fatigue loading conditions, for which a two-parameter failure criterion, in terms of accumulated inelastic strain and oxygen concentration at the crack tip, has been utilized
Mitochondrial carrier homolog 1 (Mtch1) antibodies in neuro-Behçet's disease
Cataloged from PDF version of article.Efforts for the identification of diagnostic autoantibodies for neuro-Behcet's disease (NBD) have failed. Screening of NBD patients' sera with protein macroarray identified mitochondrial carrier homolog 1 (Mtch1), an apoptosis-related protein, as a potential autoantigen. ELISA studies showed serum Mtch1 antibodies in 68 of 144 BD patients with or without neurological involvement and in 4 of 168 controls corresponding to a sensitivity of 47.2% and specificity of 97.6%. Mtch1 antibody positive NBD patients had more attacks, increased disability and lower serum nucleosome levels. Mtch1 antibody might be involved in pathogenic mechanisms of NBD rather than being a coincidental byproduct of autoinflammation. © 2013 Elsevier B.V
Dynamic regulation of canonical TGF beta signalling by endothelial transcription factor ERG protects from liver fibrogenesis
The role of the endothelium in protecting from chronic liver disease and TGFβ-mediated
fibrosis remains unclear. Here we describe how the endothelial transcription factor
ETS-related gene (ERG) promotes liver homoeostasis by controlling canonical TGFβ-SMAD
signalling, driving the SMAD1 pathway while repressing SMAD3 activity. Molecular analysis
shows that ERG binds to SMAD3, restricting its access to DNA. Ablation of ERG expression
results in endothelial-to-mesenchymal transition (EndMT) and spontaneous liver
fibrogenesis in EC-specific constitutive hemi-deficient (ErgcEC-Het) and inducible homozygous
deficient mice (ErgiEC-KO), in a SMAD3-dependent manner. Acute administration of the
TNF-α inhibitor etanercept inhibits carbon tetrachloride (CCL4)-induced fibrogenesis in an
ERG-dependent manner in mice. Decreased ERG expression also correlates with EndMT in
tissues from patients with end-stage liver fibrosis. These studies identify a pathogenic
mechanism where loss of ERG causes endothelial-dependent liver fibrogenesis via regulation
of SMAD2/3. Moreover, ERG represents a promising candidate biomarker for assessing
EndMT in liver disease
Galactic Chemical Evolution: Insights from Field Horizontal Branch Stars
Physics of Evolved Stars Conference 2015 -- 8 June 2015 through 12 June 2015 -- 119585In this study we conducted the first large-sample red horizontal branch field star survey in the Milky Way. We carried out a detailed high-resolution spectroscopic abundance analysis of the RHB candidates. We also derived 12C/13C isotopic ratios, important indicators of stellar evolution, by using the CN features mainly located around the 8004 Å. © 2015 EAS, EDP Sciences
Theory of mind and unawareness of illness in schizophrenia: Is poor insight a mentalizing deficit?
PubMed ID: 17171312This study investigates the impact of theory of mind (ToM) deficits on poor insight in schizophrenia. The scale for unawareness of mental disorder (SUMD) was administered to 58 stable outpatients with schizophrenia. First and second order false belief tasks, the Eyes test and a battery of nonToM cognitive measures were administered. The Second order false belief task was the best predictor of each global insight and symptom attribution scores of the SUMD. ToM tasks explained the substantial amount of the variance (ranging from 22.5% to 29.9%) for the insight scores and classified the significant amount of the patients who were aware of the illness correctly. WCST perseveration scores did not contribute to insight scores beyond that contributed by second order false belief tasks. The Second order ToM tasks seems to have critical importance for the awareness of the disorder. Beyond more direct self-evaluation, the awareness of the disorder and its consequences may also require the ability to evaluate the self from the perspective of others. "Understanding the others' belief about another person" may be conceptually very similar to "understanding the others' belief about self" (instead of another person). © 2006 Steinkopff Verlag
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