Establishing a relationship between perfusion rate and fluid shear stress in a 3D cell culture environment is an ongoing and challenging task faced by tissue engineers. We explore Doppler optical coherence tomography (DOCT) as a potential imaging tool for in situ monitoring of local fluid flow profiles inside porous chitosan scaffolds. From the measured fluid flow profiles, the fluid shear stre...

Background: Low shear stress caused by disturbed or turbulent flow at arterial branch points is known to associate with atherosclerosis. However, shear stress at the venous valve location and its association with deep vein thrombosis are less understood due to the complex and poorly understood bi-directional flow in the valve pocket region. We investigated how venous endothelial cells respond t...

We present an immersed boundary method based on volume penalization, with which pulsatile flow in a model cerebral aneurysm is simulated. The model aneurysm consists of a curved vessel merged with a spherical cavity. The dominant vortical structures arising in the time-dependent flow are discussed and the evolution of the maximal shear stress in the aneurysm is analyzed. We approximate flow pro...

The effect of a temporal gradient in shear and steady shear on the activity of extracellular signal-regulated protein kinases 1 and 2 (ERK1/ERK2), c-fos, and connexin43 (Cx43) in human endothelial cells was investigated. Three laminar flow profiles (16 dyn/cm(2)), including impulse flow (shear stress abruptly applied for 3 s), ramp flow (shear stress smoothly transitioned at flow onset), and st...

The migration of vascular endothelial cells under flow can be modulated by the addition of chemical or mechanical stimuli. The aim of this study was to investigate how topographic cues derived from a substrate containing three-dimensional microtopography interact with fluid shear stress in directing endothelial cell migration. Subconfluent bovine aortic endothelial cells were seeded on fibronec...

We report the first topographical data of the surface of living endothelial cells at sub-light-microscopic resolution, measurements essential for a detailed understanding of force distribution in the endothelium subjected to flow. Atomic force microscopy was used to observe the surface topography of living endothelial cells in confluent monolayers maintained in static culture or subjected to un...

Low-temperature plastic flow in TRIP steels has been found to be controlled by stress-assisted isothermal martensitic transformation. For these conditions, the thermodynamics and kinetic theory of martensitic transformations leads directly to constitutive relations predicting the dependence of flow stress on temperature, strain, strain-rate, and stress-state, consistent with the observed behavi...

The goal of the study was to assess whether pulsatile atheroprone shear stress modulates the expression of transient receptor potential (TRP) channels, TRPC3, TRPC6, TRPM7, and TRPV1 mRNA, in human umbilical vascular endothelial cells. Exposure of cultured vascular endothelial cells to defined shear stress, producing a constant laminar flow (generating a shear stress of 6 dyne/cm(2)), laminar p...

Flow-induced blood damage plays an important role in determining the hemodynamic impact of abnormal blood flow, but quantifying of these effects, which are dominated by shear stresses in highly fluctuating turbulent flow, has not been feasible. This study evaluated the novel application of turbulence tensor measurements using simulated 4D Flow MRI data with six-directional velocity encoding for...

The present review presents basic concepts of blood rheology related to vascular diseases. Blood flow in large arteries is dominated by inertial forces exhibited at high flow velocities, while viscous forces (i.e., blood rheology) play an almost negligible role. When high flow velocity is compromised by sudden deceleration as at a bifurcation, endothelial cell dysfunction can occur along the ou...