生物抗氧化剂电化学检测技术进展

生物体内的氧化与抗氧化机制是生命科学研究较广泛的课题.在氧化代谢过程中,活性氧物质或自由基(ROS)逐渐积累,当ROS相对于生物抗氧化剂(AO)过量时,会破坏生物大分子和细胞,并导致人体组织的功能损伤.因此,对AO的研究在生物化学、医学、食品科学等领域具有重要的意义.传统的AO检测一般采用自由基反应检测,热引发的ROS与AO进行氧化还原竞争反应,或者使用具有光学吸收或荧光特性的氧化剂,根据体系的光学吸收或荧光信号可以对AO进行定量分析.我们发展了几种ROS淬灭型电化学检测AO的方法,并且给出了相应的动力学模型.AO电化学检测技术的主要优点是采用了电化学原位产生的ROS(H_2O_2、·OH等)作为AO分析的氧化性物质,这些AO接近于人体内源型ROS,因此得到的氧化还原动力学数据更加接近于人体实际发生的状态.     

几种天然抗氧化剂对DNA氧化损伤的保护作用

人体在正常情况下是处于氧化．还原平衡状态的,当这种平衡被破坏,如因为体内或外界的原因引起体内自由基浓度升高,将导致生物大分子过氧化如DNA的氧化性损伤,进而引起各种疾病．目前大量的研究表明,人类的多种疾病与自由基有关,如各种炎症、癌症、自身免疫疾病、糖尿病、各种心脑血管疾病、老年性痴呆等．因此,提高抗氧化剂的摄入可能能够降低这类疾病的发生,这就是目前提出的“抗氧化剂治疗”说．合成抗氧化剂如在食品中广泛使用的二丁羟基茴香醚（BHT）和丁羟基茴香醚（BHA）由于其潜在的毒性和致癌作用被人们所排斥．     

维生素C和维生素E的联合抗氧化活性研究

维生素C和维生素E具有多种生理活性,也是抗氧化剂,二者联合作用的生化机理研究鲜见报道.本文采用铁氰化钾法、甲基紫法、邻苯三酚自氧化法和DMPD法,检测了维生素C和维生素E单独及联合作用后的还原力、对DMPD·+自由基、羟自由基和超氧阴离子的清除能力;采用SDS-PAGE法和SCGE法检测了二者对蛋白质和细胞DNA氧化损伤的保护作用.结果表明,维生素C和维生素E在各个体系中具有较强的作用,并呈浓度依赖性.维生素C在还原能力、清除自由基能力方面比维生素E强,二者的联合作用大多强于单独作用,表现出一定的协同增效作用.同时,维生素C和维生素E在AAPH引起的蛋白质氧化损伤中也有很好的保护作用,二者联合后作用效果更明显,但在对细胞DNA的氧化损伤中未见协同保护作用.     

自由基生物抗氧化与疾病

针对生物抗氧化剂这一近年来化学、生物学与医学交叉学科研究的热点 ,综述了生物体内自由基等活性氧( ROS)的产生及其引起生物细胞氧化性损伤所造成的危害 ,抗氧化剂的种类和作用 ,抗氧化剂在预防和治疗癌症、冠心病、衰老、白内障等慢性疾病中的作用 ,不同类型抗氧化剂间的协同作用 ,以及抗氧化剂研究领域的一些新动态     

运动性氧化损伤与抗氧化剂的养护作用

运动性“氧化损伤”氧自由基与抗氧化剂研究已成为21世纪运动医学研究的重要课题。抗氧化剂可以通过抗氧化作用消除活性氧对机体造成的损伤，这能为运动性损伤等问题提供一个新的治疗及养护途径。本文论述了自由基产生及对人体的影响，抗氧化剂的种类及其研究中存在的问题。     

抗氧化剂的体外化学发光分析

ＤＮＡ 氧化损伤可导致多种类型疾病的产生, 并可能与细胞的衰老过程直接相关． 体内自由基代谢和清除失衡将致使ＤＮＡ氧化损伤增加, ＤＮＡ 修复能力下降． 内源和外源性的抗氧化剂可清除过多的自由基, 使ＤＮＡ免受损伤． 抗氧化作用是一个很复杂的反应, 药物抗氧化能力的大小取决于其夺氢反应、还原作用及生成自由基的稳定性等诸因素． 本文采用Ｐｈｅｎ － Ｃｕ － ＶＣ－ Ｈ２Ｏ２ － ＤＮＡ体外化学发光体系, 研究了多种抗氧化剂对ＤＮＡ 损伤的保护作用, 并对其药物结构与抗氧化能力进行了分析．     

生物抗氧化剂的促氧化作用及其癌预防活性

流行病学和临床研究证实果蔬类食品中的生物抗氧化剂具有显著的癌预防活性,这是因为生物抗氧化剂能够抑制自由基诱导的DNA氧化性损伤.然而,生物抗氧化剂的癌预防活性最近被认为与其抗氧化性质并不相关,相反,其促氧化作用扮演着重要的角色.因此,本文简要综述了生物抗氧化剂的促氧化作用与癌预防活性之间的关系.     

体内自由基，算得出来吗？

“我有必要补充抗氧化剂吗?怎么样才会知道自己体内自由基是否过高?”“我每天吃维生素C、E,蜂胶、麦苗粉、葡萄籽萃取物等几十种抗氧化产品,深怕体内自由基过高会致癌,但却不知道每天这样补下来到底效果如何?”当愈来愈多的学术报告指出,自由基与所有慢性病的产生有密切关系之际,自由基的克星——抗氧化补充剂便成了现代人养生保健不可或缺的产品,不过补进去的抗氧化剂到底对身体的帮助有多少呢?可能真正清楚的实在不多。     

抗氧剂抗氧化活性研究进展

有机体的多种疾病都与自由基对机体的氧化损伤有关,而抗氧剂具有很强的抗氧化活性和清除自由基的能力,保护机体细胞免受自由基的攻击,因此引起广泛关注并被应用于食品技术和医药学领域．抗氧剂分为内源性抗氧剂和外源性抗氧剂两类,内源性抗氧剂包括超氧化物歧化酶、谷胱甘肽过氧化物酶和过氧化氢酶等,外源性抗氧剂包括抗坏血酸、黄酮类化合物以及酚类化合物等．对上述抗氧剂抗氧化作用机理研究现状进行了综述．     

天然药物有效成分抗氧化作用及机制研究

许多疾病如动脉粥样硬化、肿瘤、糖尿病、神经退行性疾病以及炎症等的发生和发展与机体内自由基的氧化损伤有关.从自由基与疾病关系角度综述了近年来的研究成果,为进一步研究天然药物有效成分的抗氧化作用提供参考.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has