[ effects of formaldehyde among medical students in anatomy dissection laboratory of Shiraz school of medicine]

The aim of this study is to evaluate the effects of formaldehyde vapor on eyes, nose and skin and pulmonary function of medical students, as well as, indoor concentration of formaldehyde [FA] vapor in dissection laboratory. One hundred sixty five [165] medical students were selected randomly. Students were excluded if they had had history of smoking, or any condition likely to have an effect on the results of this study. All students were exposed to formaldehyde at least one hour per week for 10 weeks. To evaluate irritation of eyes, nose and skin, pulmonary function and indoor concentration of FA vapor in anatomy laboratory we used questioner, spirometry and NIOSH 3500 method [National Institute for Occupational Safety and Health], respectively. Following exposure to FA, irritation of skin, eyes and specially nose [75.8%] were increased significantly [P

[Effects of extremely low frequency electromagnetic fields during foetal life on adulthood learning in male rat]

Background and aim: Our environment is exposed to electromagnetic fields by development and industrialization of life. The aim of this investigation was to evaluate the effects of extremely low frequency electromagnetic fields [5 and 25 Hz] during fetal life on adulthood learning in male rat

Methods: In this study forty eight Sprague Dawley pregnant rats [150+/-20g] were divided into six groups of eight: control, sham, and 5 or 25Hz and 50 or 500micro T. Duration of exposure was 4 hours per day [continuously from 8 to 12 A.M.] from first day to 15th day of gestation. We evaluated learning, body weight, brain weight, brain volume, brain weight to body weight ratio and brain density of 60 days-old male offsprings. The learning task was performed by shuttle box in the form of one-way active avoidance conditioning. The number of conditioning responses and latency periods was recorded. Data was statistically analyzed by Kruskal-wallis test

Results: Fetal life exposure to ELF EMF [25Hz/50micro T] improved learning, decreased body weight and increased brain weight to body weight ratio in male rat [P<0.05]. Fetal life exposure to 25 Hz/500 micro T, 5 Hz/500 micro T and 5 Hz/50 micro T increased body weight

Conclusion: Fetal life exposure to ELF EMF [25Hz/50micro T] could improve learning in male rats

Numerical simulation of pulsatile flow with newtonian and non-newtonian behavior in arterial stenosis

There is considerable evidence that vascular fluid dynamics plays an important role in the development and prevalence of atherosclerosis which is one of the most widespread disease in humans .The onset and prevalence of atherosclerosis hemodynamic parameter are largely affected by geometric parameters. If any obstacle interferes with the blood flow, the above parameters change dramatically. Most of the arterial diseases, such as atherosclerosis, occur in the arteries with complex patterns of fluid flow where the blood dynamics plays an important role. Arterial stenosis mostly occurs in an area with a complex pattern of fluid flow, such as coronary artery, aorta bifurcation, carotid and vessels of lower limbs. During the past three decades, many experimental studies have been performed on the hemodynamic role of the blood in forming sediment in the inner wall of the vessels. It has been shown that forming sediment in the inner wall of vessels depends on the velocity of fluid and also on the amount of wall shear stress.We have examined the effect on the blood flow of local stenosis in carotid artery in numerical form using the incompressible Navier-Stockes equations. The profile of the velocity in different parts and times in the pulsatile cycle, separation and reattachment points on the wall, the distance stability of flow and also alteration caused by the wall shear stress in entire vessel were shown and compared with two behaviors flow [Newtonian and Non-Newtonian].Finally we describe the influence of the severity of the stenosis on the separation and reattachment points for a Non-Newtonian fuid. In the present study, we have pointed very low and high oscillating WSS [Wall Shear Stress] values play a significant role in the development of forming sediment in the inner wall of vessels. Also, we obtain this probability is higher for Newtonian than Non-Newtonian fluid behavior.Based on our results, the possibility of the endothelium destruction is greater with the Newtonian fluid behavior and in the regions where WSS are beyond the range of 10-420 dyne/cm2