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排序方式: 共有194条查询结果,搜索用时 15 毫秒
11.
目的:对比四种成盐剂对头孢噻肟钠成品质量的影响。方法:通过头孢噻肟酸与成盐剂反应制得头孢噻肟钠溶液,再滴加丙酮析出头孢噻肟钠固体。结果:由碳酸氢钠制得的头孢噻肟钠质量优于其他方法。结论:使用碳酸氢钠作成盐剂,滴加丙酮结晶,简化了工艺路线,并能有效地降低生产成本,减少环境污染,适合工业化生产。 相似文献
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Imbalanced free radicals and antioxidant defense systems in schizophrenia: A comparative study 总被引:2,自引:0,他引:2
Objective: To examine changes of blood oxidative-antiovidative level in schizophrenic patients and its relationship with clinical symptoms. Methods: Forty-six Chinese patients met DSM-IV (Diagnostic and Statistical Manual of Mental Disorders-iV) criteria for schizophrenia and fifty age- and sex-matched healthy controls were enrolled in the present study. Baseline psychiatric symptom severity was assessed with brief psychiatric rating scale, positive and negative syndrome scale on the blood draw day. Fresh blood samples were collected to measure levels of nitric oxide and lipid peroxide in plasma as well as activities of superoxide dismutase, catalase and glutathione peroxidase in red blood cells by spectrophotometric assays simultaneously. Results Comparison of the biochemical parameters indicated that the level of nitric oxide and lipid peroxide increased in patient group, which represented a positive correlation with positive scale scores; while the activities of three critical enzymes decreased and showed a negative linear correlation. Conclusion: This study showed that there are dysregulation of free radical metabolism and poor activities of the antioxidant defense systems in schizophrenic patients. Excess free radicals formation may play a critical role in the etiology of schizophrenia. Using antioxidants might be an effective therapeutic approach to partially alleviate or prevent the symptoms of schizophrenia. 相似文献
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医学上常用的的苯酚 ,学生对它有弱酸性及在一定条件下能与金属钠产生氢气这一现象不易理解。通过对实验的改进 ,并让学生参与实验 ,最后结合理论开展教学活动 ,使教学达标 ,并取得良好的效果 相似文献
15.
金属氧化物沉积法制备钛酸铋钠陶瓷的研究 总被引:1,自引:1,他引:0
张寅 《山东教育学院学报》2008,23(4):75-78
金属氧化物沉积法(MOD)成功地制备了Bi1/22Na1/2TiO3(NBT)基无铅压电陶瓷,样品的X射线衍射(XRD)结果显示其具有较好的结晶性,XRD指标化后的结果表明,晶胞参数的变化,在室温下是赝立方相。通过测量不同退火条件下陶瓷表观密度,得到NBT陶瓷采用MOD法的最大密度可在烧结温度约为1150℃左右。 相似文献
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K. Poornima M. Cariappa K. Asha H. P. Kedilaya M. Nandini 《Indian journal of clinical biochemistry : IJCB》2003,18(2):197-205
An adequate antioxidant reserve which is usually present in a vegetarian diet is associated with higher life expectancy. On
the other hand habitual consumption of fish is associated with lower risk of cardiovascular diseases which is attributed to
the polyunsaturated fatty acids (PUFA) present in it. However the PUFA are readily susceptible to oxidation leading to the
formation of free radicals which is known to be involved in the causation of several diseases.
The oxidant-antioxidant status of 23 vegetarians and 22 fish eaters was studied by determining the plasma lipid peroxides
measured as malondialdehyde (MDA) and the antioxidants, viz. glutathione (GSH), ascorbic acid, ceruloplasmin and uric acid.
Results show that the ascorbic acid values were significantly higher in vegetarians. In addition, MDA correlated negatively
with ascorbic acid only in vegetarians. However, correlation of MDA with glutathione showed a significant negative correlation
only in fish eaters. There was no statistically significant difference in the MDA, GSH, ceruloplasmin and uric acid levels.
The mechanism behind these findings are not clear and needs to be explored. 相似文献
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The dissolved oxygen (DO) level in groundwateris a key parameter forin situbioremediation of con-taminated groundwater. However, due to the poorcontent of DO in groundwater, aerobic microbial deg-radation is difficult to occur in natural condition. Ear-ly work on enhancedin situbioremediation deliveredoxygen to the contaminated aquiferbyspargingairin awell, but the low solubility of oxygen increased thedifficulty and expense of maintaining aerobic condi-tions in groundwater[1]. This problem … 相似文献
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余奇飞 《Journal of Zhangzhou Technical Institute》2007,9(3):18-20
基于过氧化苯甲酰在稀硫酸介质中,对亚硝酸根使亚甲基蓝的褪色反应的抑制作用,研究了一种新的过氧化苯甲酰的检测方法。过氧化苯甲酰浓度在0.8~4.0μg/mL范围内服从比尔定律,检出限5.24×10-9g/mL。 相似文献
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