Fluid shear stress modulates vascular production of endothelial superoxide anion (O2*-) and nitric oxide (*NO). Whether the characteristics of shear stress influence the spatial variations in mitochondrial manganese superoxide dismutase (Mn-SOD) expression in vasculatures is not well defined. We constructed a three-dimensional computational fluid dynamics model simulating spatial variations in ...

AIMS Phosphorylation of forkhead box O (FoxO) transcription factors induces their nuclear exclusion and proteosomal degradation. Here, we investigated the effect of fluid shear stress on FoxO1a in primary cultures of human endothelial cells and the kinases that regulate its phosphorylation. METHODS AND RESULTS Shear stress (12 dynes/cm2) elicited the phosphorylation, nuclear exclusion, and de...

Local regulation of vascular tone plays an important role in cardiovascular control of blood pressure. Aside from chemical or hormonal regulations, this local homeostasis is highly regulated by fluid-shear stress. It was previously unclear how vascular endothelial cells were able to sense fluid-shear stress. The cellular functions of mechanosensory cilia within vascular system have emerged rece...

Large-amplitude oscillatory shear flow (LAOS) is a popular for studying the nonlinear physics of complex fluids. Specifically, the strain rate sweep (also called the strain sweep) is used routinely to identify the onset of nonlinearity. In this paper, we give exact expressions for the nonlinear complex viscosity and the corresponding nonlinear complex normal stress coefficients for the Oldroyd ...

INTRODUCTION The onset of atherosclerosis may be related to changes in vascular endothelial permeability to macromolecules, which may in turn be induced by wall shear stress or its related indices. We report here an initial experiment that correlates, site-by-site, the albumin uptake in a porcine aortic trifurcation with several measures of wall shear obtained by computational fluid dynamic (CF...

Numerous studies demonstrate that atherosclerotic lesion development occurs at the site of the blood vessel that is subjected to disturbed flow [1-3], such as the lesser curve of the aortic arch or at bifurcations. These observations have led researchers to hypothesize that different types of blood flow have different effects on the function of endothelial cells (ECs) that line the blood vessel...

It has been suggested that for fluids in which the rate of strain varies appreciably over length scales of the order of the intermolecular interaction range, the viscosity must be treated as a nonlocal property of the fluid. The shear stress can then be postulated to be a convolution of this nonlocal viscosity kernel with the strain rate over all space. In this Letter, we confirm that this post...

We study theoretically the viscoelastic properties of sheared binary fluids that have strong dynamical asymmetry between the two components. The dynamical asymmetry arises due to asymmetry between the viscoelastic stresses, particularly the bulk stress. Our calculations are based on the two-fluid model that incorporates the asymmetric stress distribution. We simulate the phase separation proces...

BACKGROUND AND PURPOSE Hemodynamics is often recognized as one of the major factors in aneurysm rupture. Flow impingement, greater pressure, and abnormal wall shear stress are all indications for aneurysm rupture. Characterizing wall shear stress for intracranial aneurysms at similar anatomic locations may help in understanding its role. MATERIALS AND METHODS Twenty-six intracranial aneurysms...

The vascular endothelium, by virtue of its position at the interface between blood and the vessel wall, is known to play a critical role in the control of thrombosis and fibrinolysis. Thrombomodulin (TM) is a surface receptor that binds thrombin and is a potent activator of the protein C anticoagulant pathway. Although TM expression is known to be regulated by various cytokines, little is known...