Vasoactive drugs are known to affect impedance (pressure/flow) and vessel wall motion in arteries. The nonlinear theory of oscillatory flow in straight elastic vessels indicates that wall shear rate is affected by changes in impedance phase angle and wall motion. To test whether wall shear rate depends on impedance phase angle and wall motion in vivo, wall shear rate was measured in the abdomin...

The dynamics of red blood cells (RBCs) in oscillatory shear flow was studied using differential equations of three variables: a shape parameter, the inclination angle θ, and phase angle ϕ of the membrane rotation. In steady shear flow, three types of dynamics occur depending on the shear rate and viscosity ratio. (i) tank-treading (TT): ϕ rotates while the shape and θ oscillate. (ii) tumbling (...

– We present a simple phenomenological model to describe shear-thickening in a wormlike micelle solution. The solution is assumed to undergo a reaction above a critical shear stress, to form a gel-like phase. There is no flow within this “gel” phase, and it is insoluble in the solution. The amount of gel in the system is determined by a competition between a stress-dependent reaction rate, whic...

metal spinning as a kind of manufacturing process has capability to shape hollow components. in present work shear spinning process is used to formplates into conical shapes. moreover, the aim of this research is to demonstrate the impact of the process parameters (i.e. feeding rate and spindle speed) on wall thickness. this approachwas done by experimental and finite elements method. the resul...

The effect of heparin on thrombogenesis induced by the subendothelium of rabbit aorta was investigated in 24 healthy volunteers after intravenous injection of different doses (0, 1000, 2500, and 5000 IU). By using an ex vivo perfusion chamber system, the interaction between flowing blood and exposed subendothelium was measured at low (50 s-1), intermediate (650 s-1), and high (2600 s-1) wall sh...

An electro-rheological (ER) fluid showing trembling shear behavior was fabricated with chitosan particles that had benzene, amine and azo-pendent side groups. This modifiedchitosan dispersed suspension showed four regions in a plot of shear stress against shear rate at high electric field. We analyzed this specific behavior with our suggested model. The model was developed with the spring-dampe...

Many experiments have measured the effect of force on the dissociation of single selectin bonds, but it is not yet clear how the force dependence of molecular dissociation can influence the rolling of cells expressing selectin molecules. Recent experiments using constant-force atomic force microscopy or high-resolution microscopic observations of pause-time distributions of cells in a flow cham...

Introduction: Flow mediated-dilation (FMD) is a noninvasive test of endothelial function based on shear stressdependent nitric oxide secretion causing vasodilation. Normalization of FMD to shear stress was previously proposed. The aim of present study is an examination of relationship between shear rate and FMD in patients with hypertension and atherosclerosis in comparison with healthy volunte...

OBJECTIVE Blood flow is considered one of the important parameters that contribute to venous thrombosis. We quantitatively test the relationship between initiation of coagulation and shear rate and suggest a biophysical mechanism to understand this relationship. METHODS AND RESULTS Flowing human blood and plasma were exposed to cylindrical surfaces patterned with patches of tissue factor (TF)...