Rats were subjected to severe incomplete cerebral ischemia followed by recirculation. The levels of several of the cyclooxygenase products of arachidonic acid were measured at 5 and 15 minutes of ischemia and at 30 minutes of recirculation following 15 minutes of ischemia, PGE2 accumulated during the first 5 min. of ischemia and its level declined at 15 min. and returned to control level at 30 ...

Using the middle cerebral artery occlusion model in cats, we evaluated the possible role of the cyclooxygenase pathway in alterations of local cerebral blood flow and the development of cortical edema following prolonged ischemia or recirculation. We divided 57 cats into three groups, and each cat received saline (control), indomethacin, or the free radical scavenger ONO-3144. Each group was su...

Laminar and turbulent numerical simulations of steady flow in an aneurysm model were carried out over Reynolds numbers ranging from 300 to 3600. The numerical simulations are validated with Digital particle Image Velocimetry (DPIV) measurements, and used to study the fluid dynamic mechanisms that characterize aneurysm deterioration, by correlating them to in vitro blood platelet deposition resu...

The object of this study is to improve the techniques for describing the lung dilution curve for shunt quantification by separating the effects of systemic recirculation on the curve form those of direct shunt return. The time of the systemic recirculation peak was estimated by determination of transit times from the right and left ventricles and lung. A gamma variate fit based on the distribut...

BACKGROUND Airborne nanoparticles from vehicle emissions have been associated with adverse effects in people with pulmonary and cardiovascular disease, and toxicologic studies have shown that nanoparticles can be more hazardous than their larger-scale counterparts. Recirculating air filtration in automobiles and houses may provide a low-cost solution to reducing exposures in many cases, thus re...

In this study, we investigate the steady propagation of a liquid plug in a two-dimensional channel lined by a uniform, thin liquid film. The liquid contains soluble surfactant that can exist both in the bulk fluid and on the air-liquid interface. The Navier-Stokes equations with free-surface boundary conditions and the surfactant transport equations are solved using a finite volume numerical sc...

The evolution of neuronal damage in various regions during ischemia and in early recovery was investigated morphologically using hyperglycemic and normoglycemic Wistar rats. Hyperglycemia (20-35 mu mol/ml plasma) was achieved with the infusion of glucose (i.v.) prior to ischemia. Forebrain ischemia (10 minutes) was induced by bilateral common carotid artery occlusion and hypotension. Normoglyce...

Flow patterns may affect the potential of thrombus formation following plaque rupture. Computational fluid dynamics (CFD) were employed to assess hemodynamic conditions, and particularly flow recirculation and vortex formation in reconstructed arterial models associated with ST-elevation myocardial infraction (STEMI) or stable coronary stenosis (SCS) in the left anterior descending coronary art...

The characteristics of physiological blood flow in human carotid arterial bifurcation model have been numerically studied using a fully coupled fluid-structure interaction (FSI) analysis. This computational model with the fluid-structure interaction is constructed to investigate the flow characteristics and wall shear stress in the carotid artery. As the flow begins to decelerate after the peak...

In order to lower the Nitrogen Oxides (NOx) concentration in internal combustion engine emissions and to improve performance, Exhaust Gas Recirculation (EGR) and Scavenging mechanism are introduced. EGR recirculates a fraction of the exhaust gas back into the cylinders, thus diluting the intake air. This lowers the maximum combustion temperature and, since the formation of NOx is heavily depend...