金水六君煎总黄酮清除氧自由基的作用

研究了金水六君煎总黄酮对羟自由基和超氧阴离子自由基的清除作用．用Fenton反应产生羟自由基，用黄嘌呤氧化酶反应系统产生超氧阴离子自由基．分别向产生羟自由基和超氧阴离子自由基的反应系统中加入金水六君煎总黄酮，两种自由基的产生量显著减小，且随着黄酮量的增加，两种自由基产生量减小得也越明显。     

大麦提取物体外抗氧化活性检测

用丙酮抽提了大麦的酚类成分并检测了总酚含量以及提取物对羟自由基、超氧阴离子的清除作用,测定了还原力和对大鼠肝微粒体脂质过氧化的一致活性.结果表明,大麦提取物能有效清除由Fenton反应产生的羟自由基及邻苯三酚自氧化产生的超氧阴离子,其活性高于Trolox;有较强的还原力和对脂质过氧化的抑制作用.结果提示大麦提取物在体外...     

放线菌类培养滤液体外自由基清除和抗氧化活性的研究

本研究了60种放线菌类培养滤液体外自由基清除和抗氧化活性．这60种放线菌类按阿拉伯数字的顺序被编号．分别采用化学反应抑制自由基产生的化学测定法和抑制红细胞溶血的生物测定法．结果显示2#、41#、45#、52#和54#同时具有高的羟自由基和超氧阴离子的清除活性，以及抑制红细胞溶血能力；36#仅有羟自由基清除活性；44#有超氧阴离子的清除活性，同时有抑制红细胞溶血能力．由此估计抑制红细胞溶血与超氧阴离子的清除活性有关，而与羟自由基清除活性无明显的关系．     

分光光度法测定Fenton体系中产生的羟自由基

Fenton反应产生的羟自由基与中性红反应,颜色发生变化,用分光光度计测定其△A520值的变化,可间接测定羟自由基的生成量,通过对测定条件的研究,得到最佳实验条件.抗氧化药物甘露醇、硫脲与羟自由基清除率具有明显的量效关系.测定了阿魏酸、芦丁等几种中药活性成分清除羟自由基的功能,此法可用于羟自由基清除剂的筛选及抗羟自由基机理研究.     

傣药纹尚海抗氧化作用研究

利用Fenton反应产生羟自由基·OH、光照核黄素产生超氧阴离子自由基O-2·,硫代巴比妥酸(TBA) 分光光度法首次对傣药纹尚海提取物体外抗氧化作用进行研究.实验结果表明纹尚海提取物能有效清除活性氧自由基,对DNA氧化损伤有显著抑制作用.     

诃子多酚清除活性氧自由基及体外抗氧化作用研究

研究诃子多酚体外抗氧化活性.利用Fenton反应产生羟自由基·OH,光照核黄素产生超氧阴离子自由基,分光光度法研究了诃子体外清除活性氧自由基的作用.用硫代巴比妥酸(TBA)分光光度法研究诃子对·OH诱发卵磷脂脂质过氧化损伤的抑制作用.表明诃子多酚能有效清除活性氧自由基,对卵磷脂脂质过氧损伤有显著抑制作用.     

黄连炮制品清除氧自由基和抗指质过氧化作用

采用体外氧自由基生成系统和羟自由基诱导的小鼠肝均浆脂质过氧化反应,研究黄连生品、清炒品和酒炙品清除氧自由基能力和抗脂质过氧化作用,评价炮制对黄连抗氧化作用的影响,研究结果表明黄连炮制品可清除次黄嘌呤－黄嘌呤氧化酶系统所产生的超氧阴离子（SAFR）和Fenton反应生成的羟自由基（HFR）,并能抑制HFR诱导的小鼠肝脏匀浆脂质过氧化作用,各炮制品EC50之间具有一定显著差异,炮制降低了黄连抗能氧化能力。     

黄连炮制品清除氧自由基和抗脂质过氧化作用

采用体外氧自由基生成系统和羟自由基诱导的小鼠肝匀浆脂质过氧化反应 ,研究黄连生品、清炒品和酒炙品清除氧自由基能力和抗脂质过氧化作用 ,评价炮制对黄连抗氧化作用的影响 .研究结果表明黄连炮制品可清除次黄嘌呤 黄嘌呤氧化酶系统所产生的超氧阴离子(SAFR)和Fenton反应生成的羟自由基 (HFR) ,并能抑制HFR诱导的小鼠肝脏匀浆脂质过氧化作用 ,各炮制品EC50 之间具有一定显著差异 ,炮制降低了黄连抗氧化能力     

白扁豆等4种中药多糖的体外抗氧化活性研究

利用Fenton反应检测石斛、益母草、沙苑子和白扁豆4种中药中的成分——多糖对羟基自由基和邻苯三酚自氧化体系产生的超氧阴离子自由基的清除作用,并对多糖抗氧化活性进行研究.结果表明,石斛、益母草和白扁豆中的多糖对超氧阴离子自由基和羟基自由基有不同程度的清除作用,而沙苑子中的多糖则具有促氧化活性.     

甘薯中清除不同自由基的活性物质提取条件的优化

在单因素试验基础上,利用正交试验,分别对甘薯中清除羟自由基和超氧阴离子自由基的两类活性物质的提取条件进行优化。结果表明,甘薯中清除羟自由基活性物质的最佳提取条件为:以水作为提取溶剂,提取剂用量45 mL/g,提取温度为45℃,提取时间2.5 h;甘薯中清除超氧阴离子自由基活性物质的最佳提取条件为:以无水乙醇作为提取溶剂,提取剂用量35 mL/g,提取温度为45℃,提取时间3.0 h。在以水作为提取溶剂的条件下,各提取因素对活性物质羟自由基清除效果的影响顺序由大到小依次为:提取温度、提取时间、提取剂用量,各因素对羟自由基清除率的影响均极显著(p0.01);在以无水乙醇作为提取溶剂的条件下,各提取因素对活性物质超氧阴离子自由基清除效果的影响顺序由大到小依次为:提取温度、提取剂用量、提取时间,各因素对超氧阴离子自由基清除率的影响均极显著(p0.01)。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the