BACKGROUND AND PURPOSE Computational fluid dynamics has become a popular tool for studying intracranial aneurysm hemodynamics, demonstrating success for retrospectively discriminating rupture status; however, recent highly refined simulations suggest potential deficiencies in solution strategies normally used in the aneurysm computational fluid dynamics literature. The purpose of the present st...

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...

We develop an analytic approach to two-dimensional flow separation control by feedback. With two wall-based actuators enclosing an array of distributed wall-shear sensors, we control the wall-shear evolution equation through its boundary values at the actuators. Using this approach, we induce separation at prescribed locations in steady and unsteady channel flows, and reduce the recirculation l...

OBJECTIVE The objective of this study is to delineate the molecular mechanisms responsible for Staphylococcus aureus-platelet adhesion as a function of physiologically relevant wall shear stresses. METHODS AND RESULTS A parallel plate flow chamber was used to quantify adhesion of wild-type, Spa-, ClfA- and SdrCDE- strains to immobilized platelet layers. In the absence of plasma, adhesion incr...

Decrease of arterial wall shear stress (WSS) is associated with higher probability of atherosclerotic plaque development in many disease conditions. End-stage renal diseases (ESRD) patients suffer from vascular disease frequently, but its nature differs from general population. This study was aimed at proving an association between common carotid wall shear stress and the presence of carotid bi...

High levels of fluid shear stress at the blood vessel wall directly stimulate von Willebrand factor (vWF)-mediated platelet adhesion and aggregation and thereby contribute to the pathogenesis of arterial thrombosis. We have found that a pathological level of arterial wall shear stress (90 dynes/cm2) induces platelet aggregation that is associated with the phosphorylation of pleckstrin, a M(r) 4...

During the analysis of reinforced concrete structures, the infill wall is usually simplified as a diagonal inclined strut to facilitate finite element modeling calculations. However, the actual seismic damage and single frame-filled wall pushover experimental results show that when the earthquake shear force is huge, the top of the infill wall and the beam–column connections are usually, thus t...

Recent shear experiments in well-entangled polymer solutions demonstrated that interfacial wall slip is the only source of shear rate loss and there is no evidence of shear banding in the micron scale gap. In this work, we experimentally elucidate how molecular parameters such as slip length, b, influence shear inhomogeneity of entangled polybutadiene (PBD) solutions during shear in a small gap...

Leukocyte adhesion through L-selectin to peripheral node addressin (PNAd, also known as MECA-79 antigen), an L-selectin ligand expressed on high endothelial venules, has been shown to require a minimum level of fluid shear stress to sustain rolling interactions (Finger, E.B., K.D. Puri, R. Alon, M.B. Lawrence, V.H. von Andrian, and T.A. Springer. 1996. Nature (Lond.). 379:266-269). Here, we sho...

INTRODUCTION AND OBJECTIVES Local factors may influence neointimal proliferation following conventional stent implantation. In this study, the relationship between wall shear stress and luminal loss after coronary stenting was assessed using a combination of angiography, intravascular ultrasound, and computational fluid dynamics. PATIENTS AND METHOD Seven patients with de novo right coronary ...