RESUMO
Objective To carry out analysis on the fatigue lifetime prediction of nitinol cardiovascular stents. Method By using the finite element method of fatigure fracture, the three dimensional nitinol cardiovascular stents were established to analyze the structure of cardiovascular stents under a physiological pulsating cyclic loading. Results Great normal stress, low fatigue life and serious fatigue damage were found to be located near the stents’knots, and stents with nitrided surface or shot peened surface were likely to have a longer fatigue life. During miniature fatigue testing, early fatigue cracks or fractures were always formed at locations near stents’knots. Conclusions The simulating results under the physiological loading are matched with related experimental results, which provide a theoretical basis for the reliability and design of the cardiovascular stents.
RESUMO
<p><b>AIM</b>To study the regulation mechanism of GP on plasma lipoprotein metabolism and To explore its mechanism of anti-lipoperoxidation in the experimental hyperglycemia rats.</p><p><b>METHODS</b>The rats were raised with high fat diet for six weeks,and the model of hyperglycemia was then established. After that, those rats were treated with high or low dose of GP and xuezhikang as a masculine comparison for four weeks. Then, those rat were executed, and detected the plasma TC, TG, LDL-C, HDL-C, GSH-Px, at the same time the SOD, CAT and MDA concentration also be mensurated.</p><p><b>RESULTS</b>The results showed that high and low dose of GP could decrease the concentration of serum LDL-C, cholesterol and triglyceride remarkably and raise the concentration of HDL-C. The activity of GSH-Px, SOD and CAT in GP groups were promoted and the level of MDA was decreased distinctly.</p><p><b>CONCLUSION</b>The GP can therapy the abnormity of serum lipid and has obviously anti-lipoperoxidation affection.</p>