Vortex blood flow with reduced blood shear stress in a vein graft has been hypothesized to promote smooth muscle cell (SMC) migration and intimal hyperplasia, pathological events leading to vein graft restenosis. To demonstrate that blood shear stress regulates these processes, we developed a modified vein graft model where the SMC response to reduced vortex blood flow was compared with that of...

background: aneurysm is a blood-filled bulge in the wall of vessels that occurred in abdominal aortic and cerebral vessels. the dilation of artery leads to aneurysm. methods: three dimensional modelling was utilized for a patient with cerebral aneurysm and a normal subject, and additional fluid-structural interaction simulation was performed. we consider pulsatile blood velocity as inlet, and b...

BACKGROUND When challenged with extracellular fluid shear stress, vascular endothelial cells are known to release nitric oxide, an important vasodilator. Here, we show that the ability of cultured endothelial cells to sense a low range of fluid shear depends on apical membrane organelles, called cilia, and that cilia are compartments required for proper localization and function of the mechanos...

Surface membrane expression and conformational activation of CD18 integrins into an open molecular configuration play critical roles in neutrophil ligand binding, membrane attachment, spreading on the endothelium, and cell migration to sites of inflammation. Previously, we observed pseudopod retraction and concomitant cleavage of CD18 by human neutrophils upon exposure to fluid shear stress. Bu...

OBJECTIVE Arterial-venous specification in the embryo has been assumed to depend on the influence of fluid mechanical forces, but its cellular and molecular mechanisms are still poorly understood. Our previous in vitro study revealed that fluid shear stress induces endothelial cell (EC) differentiation by murine embryonic stem (ES) cells. In the present study we investigated whether shear stres...

The laminar flow of a number of fluids such as polymeric liquids, food products, paints, slurries, foams, and so forth cannot be adequately described by the help of the classical linearly viscous Newtonian model. Thus, there is a need to have at hand an arsenal of non-Newtonian fluid models and over the past several decades a variety of models have been developed. While the fluids of the differ...

Synovial joints are loaded by weight bearing, stretching, and fluid-driven shear. To simulate in vitro fluid-driven shear, we developed an "oscillating Couette flow mechanical shear loader". Oscillating Couette flow mimics relative motion of articular surfaces; hence, characterizing flow-induced shear by the loader enhances understanding of mechanotransduction in the joint tissue. Here, the ana...

The relationships between fluid shear stress, a physiologically relevant mechanical force in the circulatory system, and pinocytosis (fluid-phase endocytosis) were investigated in cultured bovine aortic endothelial cells using a specially designed apparatus. Continuous exposure to steady shear stresses (1-15 dyn/cm2) in laminar flow stimulated time- and amplitude-dependent increases in pinocyto...

Electrorheological (ER) fluids change their flow properties dramatically when an electric field is applied. These fluids are usually composed of dispersions of polarizable particles in an insulating base fluid or composed of liquid crystal polymer. To build more suitable and complicated designs for application of ER fluid, the simulation of ER fluid as well as experiments are important. First, ...

Shear induced drainage of a foamy yield-stress fluid is investigated using MRI techniques. Whereas the yield stress of the interstitial fluid stabilizes the system at rest, a fast drainage is observed when a horizontal shear is imposed. It is shown that the sheared interstitial material behaves as a viscous fluid in the direction of gravity, the effective viscosity of which is controlled by she...