The effects of magnesium stearate (MgSt) and shear stress on flow properties and hydrophobicity are not well known. Blends with different concentrations of magnesium stearate and varying amounts of shear were tested using three different procedures: the FT4 Rheometer test, a tap density analyzer, and the Washburn method, to better understand the relation of lubricant concentration, amount of sh...

A compact-sized falling needle rheometer with quick operation and automatic flow analysis has been developed for viscometry of human blood. The volume of a sample of blood only needs to be 4 mL and the measuring time is within 3 min. Measured flow properties of blood are evaluated as a flow curve showing the relationship between the shear stress and shear rate. Observed flow curves of the human...

Using high-speed digital holographic microscopy and microfluidics, we discover that, when encountering fluid flow shear above a threshold, unicellular green alga Dunaliella primolecta migrates unambiguously in the cross-stream direction that is normal to the plane of shear and coincides with the local fluid flow vorticity. The flow shear drives motile microalgae to collectively migrate in a thi...

The interactions of blood flow with complex vessel geometry generate hemodynamic characteristics, including the heterogeneous spatial and temporal mechanical forces acting on the vessel wall. Vascular endothelial cells (ECs) covering the inner surface of blood vessels are constantly exposed to shear stress because of the frictional force created by the blood flow. ECs respond to the changes of ...

Hindered barrier function has been implicated in the initiation and progression of atherosclerosis, a disease of focal nature associated with altered hemodynamics. In this study, endothelial permeability to macromolecules and endothelial electrical resistance were investigated in vitro in monolayers exposed to disturbed flow fields that model spatial variations in fluid shear stress found at ar...

Understanding how bacteria move close to a surface under various stimuli is crucial for a broad range of microbial processes including biofilm formation, bacterial transport and migration. While prior studies focus on interactions between single stimulus and bacterial suspension, we emphasize on compounding effects of flow shear and solid surfaces on bacterial motility, especially reorientation...

Background: The interaction between the blood and the vessel wall is of great clinical interest in studying cardiovascular diseases, the major causes of death in developed countries.Objective: To understand the effects of incorporating fluid-structure interaction into the simulation of blood flow through an anatomically realistic model of abdominal aorta and renal arteries reconstructed from CT...

A volume-penalizing immersed boundary method is presented that facilitates the computation of incompressible fluid flow in complex flow domains. We apply this method to simulate the flow in cerebral aneurysms, and focus on the accuracy with which the flow field and the corresponding shear stress field are computed. The method is applied to laminar, incompressible flow in curved cylindrical vess...

BACKGROUND The effect of temporal and spatial gradients in shear on primary human endothelial cell (HUVEC) proliferation was investigated. The sudden-expansion flow chamber (SEFC) model was used to differentiate the effect of temporal gradients in shear from that of spatial gradients. With a sudden onset of flow, cells are exposed to both temporal and spatial gradients of shear. The temporal gr...