2,713 research outputs found
New horizons in computer analysis of damage and fracture in quasi-brittle materials
Continuum approaches are reviewed which can properly model localised deformations that act as a precursor to final fracture in quasi-brittle materials. Next, one such higher-order damaging continuum model is combined with a stochastic approach to describe the heterogeneity in quasi-brittle materials
New horizons in computer analysis of damage and fracture in quasi-brittle materials
Continuum approaches are reviewed which can properly model localised deformations that act as a precursor to final fracture in quasi-brittle materials. Next, one such higher-order damaging continuum model is combined with a stochastic approach to describe the heterogeneity in quasi-brittle materials
Some future directions in computational failure mechanics
Continuum approaches are reviewed which can properly model localised deformations that act as a precursor to final fracture in quasi-brittle materials. Next, one such higher-order damaging continuum model is combined with a stochastic approach to describe the heterogeneity in quasi-brittle materials
A new combined clustering method to analyse the potential of district heating networks at large-scale
Sex hormone-binding globulin regulation of androgen bioactivity in vivo : validation of the free hormone hypothesis
Sex hormone-binding globulin (SHBG) is the high-affinity binding protein for androgens and estrogens. According to the free hormone hypothesis, SHBG modulates the bioactivity of sex steroids by limiting their diffusion into target tissues. Still, the in vivo physiological role of circulating SHBG remains unclear, especially since mice and rats lack circulating SHBG post-natally. To test the free hormone hypothesis in vivo, we examined total and free sex steroid concentrations and bioactivity on target organs in mice expressing a human SHBG transgene. SHBG increased total androgen and estrogen concentrations via hypothalamic-pituitary feedback regulation and prolonged ligand half-life. Despite markedly raised total sex steroid concentrations, free testosterone was unaffected while sex steroid bioactivity on male and female reproductive organs was attenuated. This occurred via a liganddependent, genotype-independent mechanism according to in vitro seminal vesicle organ cultures. These results provide compelling support for the determination of free or bioavailable sex steroid concentrations in medicine, and clarify important comparative differences between translational mouse models and human endocrinology
VE-cadherin and claudin-5: it takes two to tango
Endothelial barrier function requires the adhesive activity of VE-cadherin
and claudin-5, which are key components of adherens and tight endothelial
junctions, respectively. Emerging evidence suggests that VE-cadherin controls
claudin-5 expression by preventing the nuclear accumulation of FoxO1 and
-catenin, which repress the claudin-5 promoter. This indicates that a crosstalk
mechanism operates between these junctional structures
Percolation, Morphogenesis, and Burgers Dynamics in Blood Vessels Formation
Experiments of in vitro formation of blood vessels show that cells randomly
spread on a gel matrix autonomously organize to form a connected vascular
network. We propose a simple model which reproduces many features of the
biological system. We show that both the model and the real system exhibit a
fractal behavior at small scales, due to the process of migration and dynamical
aggregation, followed at large scale by a random percolation behavior due to
the coalescence of aggregates. The results are in good agreement with the
analysis performed on the experimental data.Comment: 4 pages, 11 eps figure
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