Numerical and Experimental Investigation of Newtonian Flow around a Confined Square Cylinder

The confined flow of a Newtonian fluid around a square cylinder mounted in a rectangular channel was investigated both numerically and experimentally. Ratio between the pipe and channel height, the blockage ratio, is kept constant at 1/4. The flow variables including streamlines, vorticity and drag coefficients were calculated at 0 ≤ Re ≤ 50 using finite volume method. The velocity terms in the momentum equations are approximated by a higher-order and bounded scheme of Convergent and Universally Bounded Interpolation Scheme for the Treatment of Advection (CUBISTA). Particle Image Velocimetry (PIV) was also used to obtain the two-dimensional velocity field. The flow measurements were conducted for 1 ≤ Re ≤ 50. Streamline and vorticity results obtained by PIV are compared with those of the numerical simulation. Based on this comparison, good agreement is found between the numerical and experimental results in a qualitative manner

Flow Characterization of Viscoelastic Fluids around Square Obstacle

This study focuses on the computational implementation of structured non-uniform finite volume method for the 2-D laminar flow of viscoelastic fluid past a square section of cylinder in a confined channel with a blockage ratio 1/4 for Re = 10-4, 5, 10 and 20. Oldroyd-B model (constant viscosity with elasticity) and the PTT model (shear-thinning with elasticity) are the constitutive models considered. In this study effects of the elasticity and inertia on the drag coefficients and stress fields around the square cylinder are obtained and discussed in detail. With an increase elasticity, drag coefficients get smaller due to stronger shear thinning effects for PTT fluid, however, the drag coefficients show slightly enhancement for the Oldroyd-B fluid

EFFECT OF EXERCISE ON APPETITE-REGULATING HORMONES IN OVERWEIGHT WOMEN

Over the past decade, our knowledge of how homeostatic systems regulate food intake and body weight has increased with the discovery of circulating peptides such as leptin, acyl ghrelin, des-acyl ghrelin and obestatin. These hormones regulate the appetite and food intake by sending signals to the brain regarding the body’s nutritional status. The purpose of this study was to investigate the response of appetite-regulating hormones to exercise. Nine overweight women undertook two 2 h trials in a randomized crossover design. In the exercise trial, subjects ran for 60 min at 50% of maximal oxygen uptake followed by a 60 min rest period. In the control trial, subjects rested for 2 h. Obestatin, acyl ghrelin, des-acyl ghrelin and leptin concentrations were measured at baseline and at 20, 40, 60, 90 and 120 min after baseline. A two-way ANOVA revealed a significant (P<0.05) interaction effect for leptin and acyl ghrelin. However, changes in obestatin and des-acyl ghrelin concentration were statistically insignificant (P>0.05). The data indicated that although acute treadmill exercise resulted in a significant change in acyl ghrelin and leptin levels, it had no effect on plasma obestatin and des-acyl ghrelin levels

Suicide attempt with clopidogrel

We report the case of a 49-year-old male who took an overdose of 1650 mg of clopidogrel with suicidal intend. The patient developed abnormalities of platelet aggregation, but never developed symptoms. Clopidogrel is a commonly prescribed drug. Reports of overdose of clopidogrel were very rarely reported in the literature

Total antioxidant status, lipid parameters, lipid peroxidation and glutathione levels in patients with acute myocardial infarction

Free oxygen radicals and subsequent lipid peroxidation are considered to be responsible for coronary artery disease. We conducted this study to determine the blood paramenters concerning the oxidative process in acute myocardial infarction. Plasma total antioxidant status (TAS), total cholesterol (TC), triglyceride (TG), high-density lipoproteins (HDL-C), low-density lipoproteins (LDL-C) and thiobarbituric acid reactive substance ((TBARS) levels were examined as well as erythrocyte TBARS and glutathione (GSH) in 20 patients with acute myocardial infarction (AMI) admitted to the Emergency Department in Instabul University, Istanbul Faculty of Medicine, and in healthy matched control subjects. As compared to healthy controls, plasma TBARS, T-C, TG and LDL-C levels were significantly elevated in patients with AMI (P < 0.01). There were significant associations between the HDL-C levels and TAS of patients and controls, positive correlations between erythrocyte GSH and TBARS, TC and LDL-C, TC and TG levels and a negative correlation between TAS and plasma TBARS. We conclude that oxidative stress may play an important role in acute myocardial infarction. (C) 1998 Chapman & Hall Ltd

Lens opacities in Bloom syndrome: Case report and review of the literature

Bloom syndrome is an autosomal recessive disorder characterized by proportionate short stature, photosensitivity, immunodeficiency, hypogonadism and a tendency to develop various malignancies. The greatly increased frequency of sister chromatid exchanges (reciprocal exchange of homologous segments between the two sister chromatids of a chromosome) is regarded as pathognomonic for BS. We describe an 18-year old girl who presented with short stature. She was diagnosed with BS based on an extremely increased frequency of sister chromatid exchanges. Ophthalmological examination revealed mild lens opacities bilaterally, which, to our knowledge, has not been previously reported to be associated with BS