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The purpose of the present study was to evaluate the healing pattern of an experimentally induced osteotomy in Hartley guinea pigs in the presence of static magnetic and pulsed electromagnetic fields. The sample consisted of 30 Hartley guinea pigs 2 weeks of age divided into 3 groups: pulsed electromagnetic, static magnetic, and control. An osteotomy was performed in the mandibular postgonial area in all groups under general anesthesia. During the experimental period of 9 days, the animals were kept in experiment cages 8 hours per day, the first two groups being in the presence of pulsed electromagnetic and static magnetic field, respectively. Based on histologic results, both static and pulsed electromagnetic fields seemed to accelerate the rate of bone repair when compared to the control group. The osteotomy sites in the control animals consisted of connective tissue, while new bone had filled the osteotomy areas in both magnetic field groups.  相似文献   
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以光气和四溴双酚A(TBBPA)为原料经光气界面缩聚,合成了四溴双酚A聚碳酸酯,并对四溴双酚A与光气投料比、催化剂种类及其用量、分子量调节剂用量4个因素进行考察。优化工艺条件为:四丁基氢氧化铵为催化剂,对叔丁基酚(TBP)为分子量调节剂,n(四溴双酚A)∶n(光气)=1∶1.3,n(四溴双酚A)∶n(对叔丁基酚)=1∶0.028,n(四溴双酚A)∶n(四丁基氢氧化铵)=1∶0.022。该方法操作简单,产品分子量分布窄,易于工业化生产。  相似文献   
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The prevalence of hepatitis B surface antigen (HBsAg) was studied in 103 cases of hepatosplenic schistosomiasis (HSS), 134 control cases with a variety of illnesses including hepatointestinal schistosomiasis, and 600 blood donors, in an area endemic for both schisfosomiasis and viral hepatitis. The patients with HSS proved to be persistent carriers for HBsAg in a significantly higher proportion than the other two groups of cases. The HSS cases who were carriers of HBsAg had more clinical signs of chronic liver disease and strikingly more chronic inflammation of the portal spaces on liver biopsy. It is suggested that abnormal immunological responses in patients with HSS makes them more susceptible to become carriers of HBsAg and that the addition of this injurious factor makes their basic disease worse, and may be responsible for the development of cirrhosis in some cases.  相似文献   
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螺旋曲面的数字化测量及数据处理技术   总被引:3,自引:0,他引:3  
应用三坐标测量机对螺旋曲面进行数字化测量,提出了区别于传统自由曲面测量的针对螺旋曲面数字化测量的简化方法,同时提出了测量数据处理的方法.并通过测量实例证明了该技术的有效性.  相似文献   
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Calcitonin is a peptide hormone secreted by C-cells which, in humans, are found mainly in the thyroid gland. It now seems that a major physiological function of this hormone in man is the long-term maintenance of the skeleton achieved by control of bone resorption. A marked sex difference in circulating calcitonin levels normally exists, with a relative deficiency in women as compared to men. It has now been found that oestrogens regulate calcitonin secretion and it appears likely that the loss of ovarian function at the menopause accelerates the natural decline in calcitonin secretion which occurs with age. Thus, post-menopausal women are more markedly calcitonin-deficient. Levels of the bone-resorbing hormones, parathyroid hormone (PTH) and 1,25 dihydroxyvitamin D are not elevated post-menopausally and it seems likely that the increased bone resorption which leads to post-menopausal bone loss is due mainly to the loss of oestrogen and calcitonin secretion.  相似文献   
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