大麦耐非生物胁迫相关分子标记研究进展

综述分子标记在大麦耐非生物胁迫研究中的应用及其研究进展,包括发育基因效应、野生种或地方种的变异、遗传(QTLs)图谱等。现代引种和育种过程引起物种的遗传变异趋于狭窄、多样性减少,由此可能加重疾病、害虫和非生物胁迫等危害的潜在威胁。发育基因对环境胁迫具有较强的多态性效应;野生大麦和原始地方种为提高耐胁迫性提供了丰富的遗传变异资源。大麦遗传多样性的分离鉴定、遗传图谱构建、及数量性状位点(QTL)分析和分子标记辅助选择,将有助于更好地利用野生种质优良抗性,更有效的选择耐(抗)性基因型。文末从正反两方面简要讨论了分子标记在大麦耐非生物胁迫遗传育种研究中作用。     

Evidence for oxidative stress in osteoarthritis

Evidence of increased oxidative stress in patients of osteoarthritis in comparison with healthy control subjects was investigated by measuring the thiobarbituric acid reactive substances (TBARS), vitamin C, reduced glutathione (GSH) and the activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) in erythrocytes. It was observed that osteoarthritis patients were more susceptible to oxidative damage than controls as evident from increased TBARS and decreased ascorbic acid, GSH, catalase and GPx in erythrocytes. Significant increase in SOD activity found in patients might be an adaptive response. With the understanding of the role of antioxidants in arthritis, it is becoming increasingly clear that these agents seem to be beneficial in osteoarthritis.     

新兴煤矿地质构造体系分析

能过简单的力学分析,总结新兴煤矿断层发展、发育规律。     

Oxidative stress and disturbance in antioxidant balance in beta thalassemia major

Repeated blood transfusion in beta thalassemia major patients may lead to peroxidative tissue injury by secondary iron overload. In the present study, 72 children with beta thalassemia major were included. Serum levels of total lipid peroxides, Iron, Total Iron Binding Capacity, Copper, Zinc, Vitamin E, plasma Total Antioxidant Capacity, activity of Erythrocyte Superoxide Dismutase, were measured. The findings were compared with 72 age matched healthy controls irrespective of sex. A significant increase in the levels of lipid peroxide and Iron (p<0.001), whereas, significant decrease in the levels of vitamin-E, Total Antioxidant Capacity and Total Iron Binding Capacity (p<0.001) was observed. Serum Zinc was significantly increased (p<0.001) with significant decrease in the levels of copper (p<0.001). Non Significant increase in the activity of Erythrocyte Superoxide Dismutase (p>0.05) was found in the patients when compared with controls. This suggest that oxidative stress and reduced antioxidant defense mechanism play an important role in pathogenesis of beta thalassemia major.     

高中生生活压力、应对方式对其心理健康的影响

文章探讨了高中生生活压力与应对方式对其心理健康的影响。采用高中生生活压力问卷、高中生应对方式问卷和中学生心理健康量表对807名高中生进行了调查,运用典型相关和逐步多元回归分析的方法处理。结果发现,高中生生活压力、应对方式与心理健康之间有显著的典型相关;高中生生活压力与应对方式对其心理健康水平具有联合预测的功能;其中,主观生活压力中的同伴关系压力和应对方式中的内部消极评价具有最大的预测力;生活压力与应对方式中有11个变量能共同解释高中生整体心理健康水平63.9%的变异量。     

MSC.Marc有限元分析软件在焊接残余应力和变形模拟中的应用

焊接是工程制造领域广泛使用的一种高效构件成型制造技术,但焊接过程中因焊接局部加热而形成的残余应力和变形是在工程制造中不希望出现的。焊接数值模拟能较为准确预测焊接构件中的焊接残余应力和变形的分布情况,可用以指导制造过程中焊接工艺参数的优化和焊接顺序的选择,为降低试验成本和缩短产品制造周期提供了一种可行的方法。对MSC.Marc软件焊接模拟热源模型、材料模型以及其在焊接残余应力和变形模拟中的应用情况作了介绍。     

Effect of carbon, silicon, and manganese content on mean flow stress at elevated temperature

Ten studied steels including different carbon content, silicon content, and manganese content were deformed in compression over a temperature range of 600 C to 1 000 C at the strain rate of 1 s1. The curves of the mean flow stress-deformation temperature were drawn up. The mean flow stresses of higher carbon content steels decreased continuously as the applied deformation temperature increased in the whole temperature range, while the mean flow stress of lowest carbon steel displayed an abrupt drop near the two phases region. The reason for the abrupt drop phenomena was explained as the result of phase transformation. The mean flow stresses of steels with high silicon content and low manganese content also have this phenomena.     

2Cr13MnMoCu型白口铸铁耐磨性的研究

研究了2Cr13MnMoCu型高铬合金白口铸铁,经不同的热处理工艺处理,对材料的组织、性能的影响;在低应力软磨料磨粒磨损时,基体中碳化物的数量及弥散度、回火马氏体量、残余奥氏体量以及材料的硬度、韧性都是影响磨损率的重要因素,其中,碳化物的数量、分布是影响磨损率的最主要因素。通过试验获得经1050℃淬火,450℃回火时,材料的综合机械性能较好．磨损率最低。     

国外教师压力源研究的新进展

近十年来,教师压力水平普遍在提高。了解教师压力源是有效解决教师压力问题的必经之路。合理利用国外教师压力源的近期研究成果有助于我们缓解教师压力。     

浅析三相交流异步电动机电子软启动器

介绍了三相交流异步电动机的几种传统启动器及新型电子软启动器的工作原理与运行特点,并作了优缺点对比,指出了异步电动机启动器的选择方向.