Darcy flow is a steady-state model for laminar flow of a fluid through a porous medium. The present work proposes an extended model of laminar Darcy flow by introducing dynamic pressure and velocity to the classical formulation. The solution of the proposed time-space model is attained by discretizing the problem with a stabilized mixed Galerkin method in space and a forward Euler method in tim...

Effects of increments in intraocular pressure on the blood flow in the retina and. the distal part oj the optic nerve were investigated in monkeys with the use of untabeled microspheres. Moderate elevations in intraocular pressure which reduced the perfusion pressure (mean arterial blood, pressure — intraocular pressure) to levels above 40 cm H2O had only small effects in the retina and. the pr...

Shear stress imposed by blood flow is crucial for maintaining vascular homeostasis. We examined the role of shear stress in regulating SIRT1, an NAD(+)-dependent deacetylase, and its functional relevance in vitro and in vivo. The application of laminar flow increased SIRT1 level and activity, mitochondrial biogenesis, and expression of SIRT1-regulated genes in cultured endothelial cells (ECs). ...

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...

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...

We present several observations into spiral turbulence in a Taylor-Couette geometry gained through a three-dimensional direct numerical simulation. Conditionally averaged flow statistics show the persistence of an azimuthal gradient of the mean flow across both the turbulent and laminar spirals, and distinct distribution features of the turbulent intensity. The data provide a physical picture q...

The aim of this study was to determine the effect of ethanol on endothelial nitric oxide synthase (eNOS), the enzyme responsible for the production of the important vasoactive agent nitric oxide. The effect of ethanol (0.8-160 mM) on both basal and flow-stimulated eNOS activity was determined using cultured bovine aortic endothelial cells (EC). In "static" EC ethanol dose-dependently increased ...

Fluid shear stress is an important regulator of vascular and endothelial cell (EC) functions. Its effect is dependent not only on magnitude but also on flow type. Although laminar flow predominates in the vasculature, transitional flow can occur and is thought to play a role in vascular diseases. While a great deal is known about the mechanisms and signaling cascades through which laminar shear...

introduction hydrograph of springs represents clearly all physical processes that control ground water flows inside aquifer (kuto et al., 2012: 41). study of the curve can reveal information about structure and function of aquifer, particularly hydrodynamic parameters including permeability and storage (troch et al., 1993: 228). analysis of recession curve has the advantage to calculate paramet...

We consider the effect of intra-channel mass and heat transfer in modeling the performance of diesel oxidation catalysts. Many modeling studies have assumed that the intra-channel flow is laminar and, thus, heat and mass transfer between the bulk gas and wall are appropriately described using correlations for fully-developed laminar flow. However, recent experimental measurements of CO and hydr...