复杂氧化还原反应系数配平问题的探讨

《无机及分析化学》是一门基础理论课,在教学过程中,要使学生所学内容能加深理解、灵活应用,并提高分析问题和解决问题的能力,就必须引导学生在复习的基础上做些习题,以此得到巩固。本文分析了复杂氧化还原反应配平系数的问题,以教材中习题为例,进行了讨论和演算。     

蒸汽发生-原子荧光光谱法测定山楂叶中痕量砷和汞

采用蒸汽发生-原子荧光光谱法,分别在酒石酸和柠檬酸介质中分析山楂叶中砷(As)、汞(Hg)的含量,考察仪器操作条件、反应介质及共存离子等对测定As、Hg的影响.方法检出限为As:0.75μg/kg,Hg:0.034μg/kg.     

乙醛发生器

对于乙醇催化氧化成乙醛的化学实验，高中教材多采用加热螺旋状铜丝至红热，再伸人到盛有乙醇的试管中，上下移动。铜丝保持红热且闻到乙醛难闻的气味。我现设计了一个乙醛发生器，对此实验进行改进，并能用银镜反应检验产生的乙醛。     

高三化学实验分析与实验教法建议——第三单元 化学反应中的物质变化和能量变化

本单元教材是高中化学重点内容之一。教材中的前三节重点讨论了氧化还原反应和离子反应中有关物质的变化：后两节则着重讨论在化学反应中的能量变化。     

总结方法掌握规律

氧化还原反应在高中化学教材中既是重点也是难点，同时也是高考的知识点之一。教学实践表明，学生对氧化还原反应的理解和掌握比较模糊，往往概念不清，思路不明，做题不少，不得其法，尤其是氧化还原反应计算方面的习题，更是老师讲得明白，学生听得糊涂。下面试介绍一种方法，以期学生对氧化还原反应认识的深化与完善，提高学习效率，做一题，得一法，通一类，会一片。     

不对称催化合成--2001年诺贝尔化学奖简介

2001年诺贝尔化学奖奖给美国化学家诺尔斯，夏普莱斯和日本化学家野依良治，表彰他们在不对称催化合成研究方面的开创性工作，这一工作不仅解求了长期以来进行化学合成时总是得到外消旋体的困惑，而且随着研究深入，研究范围的扩大，很快应用到生产上，为制药，农药，香料等工业带来巨大的效益，本文简介了与之有关的内容。     

镉胁迫对小麦幼苗叶片生理特性的影响

以兰黑粒小麦92-1和小偃15幼苗为材料,采用室内水培试验研究了不同浓度镉(Cd)处理对保护酶活性、质膜氧化程度和渗透调节物质含量的影响。结果表明:2种品种的超氧化物岐化酶(SOD)和过氧化氢酶(CAT)在胁迫3 d后随着Cd浓度先增加后下降,胁迫6 d后呈下降趋势;除兰黑粒92-1超氧化物酶(POD)和可溶性蛋白在胁迫3 d后随Cd浓度先增加后下降外,其余各处理呈下降趋势;2种品种的丙二醛(MDA)含量、相对电导率、脯氨酸和可溶性糖在胁迫3 d和6 d后均随着Cd浓度的增加而增加,且部分增加呈显著性。兰黑粒92-1具有相对较高地保护酶活性和渗透调节物质、较轻地质膜氧化程度,表现出对镉胁迫相对较强的耐受能力。     

Oxidative stress and damage induced by abnormal free radical reactions and IgA nephropathy

Objective: To estimate the oxidative stress and oxidative damage induced by abnormal free radical reactions in IgA nephropathy (IgAN) patients' bodies. Methods: Seventy-two IgA N patients (IgANP) and 72 healthy adult volunteers (HAV) were enrolled in a random control study design, in which the levels of nitric oxide (NO) in plasma, lipoperoxide (LPO) in plasma and in erythrocytes, and vitamin C (VC), vitamin E (VE) and β-carotene (β-CAR) in plasma as well as the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in erythrocytes were determined with spectrophotometric mothods. Results: Compared with the HAV group, the averages of NO in plasma, and LPO in plasma and in erythrocytes in the IgANP group were significantly increased (P＜0.0001), while those ofVC, VE and β-CAR in plasma as well as those of SOD, CAT and GPX in erythrocytes in the IgANP group were significantly decreased (P＜0.0001). Linear correlation analysis showed that with the increase of the values of NO, and LPO in plasma and in erythrocytes, and with the decrease of those ofVC, VE, β-CAR,SOD, CAT and GPX in the IgAN patients, the degree of histological damage of tubulointerstitial regions was increased gradually (P＜0.0001); and that with the prolongation of the duration of disease the values of NO, and LPO in plasma and erythrocytes were increased gradually, while those of VC, VE, β-CAR, SOD, CAT and GPX were decreased gradually (P＜0.005). The discriminatory correct rates of the above biochemical parameters reflecting oxidative damage of the IgAN patients were 73.8%-92.5%, and the correct rates for the HAV were 70.0%-91.3% when independent discriminant analysis was used; and the correct rate for the IgAN patients was increased to 98.8%, the correct rate for the HAV was increased to 100% when stepwise discriminant analysis was used. The above biochemical parameters' reliability coefficient (alpha) were used to estimate the oxidative damage of the IgAN patients as 0.8145, the standardized item alpha=0.9730, F=53273.5681, P＜0.0001. Conclusions: A series of free radical chain reactions caused serious pathological aggravation in the IgANP' bodies, thus resulting in oxidative damage in their bodies. In treating IgANP, therefore, it is necessary that suitable dose antioxidants should be supplemented to them so as to alleviate the oxidative damage in their bodies.