Nitric oxide (NO) plays a central role in the control of vascular homeostasis. Adequate NO production stimulated by continuous laminar flow on the endothelial surface, so-called shear stress, prevents endothelial inflammation and development of endothelial dysfunction. Recently, a novel class of mechanosensitive transcription factors has been identified that in endothelial cells transfer shear ...

The purpose of this research was to examine the evolution of arterial shear stress-induced intimal albumin permeability and coevolving structural responses in swine arteries. Uniform laminar shear-stress responses were compared with those of a simulated "flow separation" stress field. These fields were created using specially designed flow-configuring devices in an experimentally controlled, me...

This paper discusses a novel dynamic resonant wall shear stress sensor concept based on an oscillating sensor operating near resonance. The interaction between the oscillating sensor surface and the fluid above it is modelled using the unsteady laminar boundary layer equations. The numerical experiment shows that the effect of the oscillating shear stress is well correlated by the Hummer number...

A sequence of direct simulations is used to study mechanisms for the growth of secondary circulations and turbulence in stratified shear flows. Five cases are examined, of which four deliver Holmboe waves as the primary instability and the fifth generates Kelvin-Helmholtz billows. Secondary circulations range in strength from weak, laminar motions to turbulence that destroys the parent wave. Pr...

Presented in this paper is an analytic approximation to the thermal-fluid problem involving mixed and forced convective heat transfer from a rotating isothermal cylinder placed in a non-uniform stream shear-flow. The approximation is obtained using a series expansion of the scaled boundary layer equations in terms of a boundary layer variable which is directly proportional to the time variable ...

Gene expression profiling has revealed that cultured vascular endothelial cells (EC) respond to fluid mechanical forces by modulating the mRNA level of a large number of genes. However, differences between the gene arrays and the experimental conditions employed by different researchers make comparison between data sets difficult, and limit the interpretation of the results. Despite these probl...

We have studied the distribution of monocyte-macrophages, lipids, and lipoproteins in sections of aorta and aortic valves from mice fed an atherogenic diet. By immunocytochemical analysis with Mac-1 and F4/80 antibodies, apolipoprotein B antibody, and oil red O staining, three discrete regions were identified: 1) the aortic wall of the sinus of Valsalva, which contained deposits of lipid that c...

The luminal surface of rat lung microvascular endothelial cells in situ is sensitive to changing hemodynamic parameters. Acute mechanosignaling events initiated in response to flow changes in perfused lung microvessels are localized within specialized invaginated microdomains called caveolae. Here we report that chronic exposure to shear stress alters caveolin expression and distribution, incre...

Most acute coronary events occur in the upstream region of stenotic atherosclerotic plaques that experience laminar shear stress (LSS) elevated above normal physiological levels. Many studies have described the atheroprotective effect on endothelial behavior of normal physiological LSS (approximately 15 dynes/cm(2)) compared to static or oscillatory shear stress (OSS), but it is unknown whether...

Laminar free convection flow of viscous, incompressible fluid with variable viscosity and viscous dissipation through two horizontal parallel walls embedded in a porous medium is studied. Arrhenius model is used in which the variable viscosity is used to be decreasing exponentially with temperature. An approximation technique is defined to obtain the solution of the coupled non-linear equations...