the aim of this research is to investigate the effect of carbon fiber reinforced polymer (cfrp) composite fabric on monotonic and fatigue behaviors of reinforced concrete beams. to control the failure occurrence, a small notch was induced at the middle span in bottom surface for all of the studied rc specimens. totally 12 beams were tested from which 6 beams tested under monotonic and 6 other t...

Atherosclerosis begins as local inflammation of arterial walls at sites of disturbed flow, such as vessel curvatures and bifurcations with low shear stress. c-Jun NH₂-terminal kinase (JNK) is a major regulator of flow-dependent gene expression in endothelial cells in atherosclerosis. However, little is known about the in vivo role of JNK in low shear stress in atherosclerosis. We aimed to obser...

BACKGROUND Regions in the vasculature exposed to steady laminar flow have a lower likelihood for atherosclerosis than regions exposed to disturbed flow with low shear stress. We previously found that laminar flow of short duration inhibited tumor necrosis factor (TNF)-alpha-mediated proinflammatory signaling in cultured endothelial cells (ECs). However, mechanisms responsible for the atheroprot...

Slow and dense granular flows often exhibit narrow shear bands, making them ill suited for a continuum description. However, smooth granular flows have been shown to occur in specific geometries such as linear shear in the absence of gravity, slow inclined plane flows and, recently, flows in split-bottom Couette geometries. The wide shear regions in these systems should be amenable to a continu...

In startup of steady shearing flow of two viscous unentangled liquids, namely low-molecular-weight polystyrene and -Dglucose, the shear stress catastrophically collapses if the shear rate is raised above a value coresponding to a critical initial shear stress of around 0.1-0.3 Mpa. The time-dependence of the shear stress during

Shear stress measured on three different cushioning materials 1 Summary Shear force is an important component of the mechanical load on a person that is supported by a surface. Too high shear force leads to occlusion of blood flow, which is seen as one of the most important factors behind pressure sores and discomfort. In the present study the influence of three different cushioning materials (...

BACKGROUND The complement system is implicated in the pathogenesis of atherosclerosis. Complement has been shown to activate endothelial cells (ECs) by inducing a proinflammatory response. Physiological levels of shear stress exert potent antiatherosclerotic effects. Therefore, we investigated whether shear stress antagonizes the effects of complement on ECs. METHODS AND RESULTS Incubation of...

Shear stress is a major determinant of endothelial apoptosis, but its role in the in vivo release of shed membrane microparticles by endothelial cells remains unknown. Thus, we sought to evaluate the possible relationship between circulating endothelial microparticle levels and laminar shear stress in end-stage renal disease patients with high cardiovascular risk, whose levels of endothelial mi...

A bifurcating arterial system with Poiseuille flow can function at minimum cost and with uniform wall shear stress if the branching exponent (z) = 3 [where z is defined by (D(1))(z) = (D(2))(z) + (D(3))(z); D(1) is the parent vessel diameter and D(2) and D(3) are the two daughter vessel diameters at a bifurcation]. Because wall shear stress is a physiologically transducible force, shear stress-...

Atherosclerotic plaques preferentially localize at arterial regions exposed to turbulent low-shear flow. Urokinase-type plasminogen activator (uPA) plays a role in vascular remodeling by facilitating smooth muscle cell migration and proliferation in addition to the proteolysis of extracellular matrix, and the expression of uPA is elevated in atherosclerotic lesions. In this study, we analyzed t...