硒酸钠与牛血清白蛋白相互作用的机理分析

在模拟动物体生理条件下,采用荧光光谱、紫外-可见吸收光谱等方法研究不同温度下硒酸钠与牛血清白蛋白的相互作用,并通过计算二者相互作用时的热力学参数及检测硒酸钠对牛血清白蛋白构象的影响,对其相互作用机理进行分析。结果表明,硒酸钠对牛血清白蛋白的荧光有猝灭效应,二者反应形成复合物,硒酸钠对牛血清白蛋白的荧光猝灭方式属于静态猝灭;硒酸钠与牛血清白蛋白主要靠静电相互作用力结合,且相互作用是自发进行的,二者的结合位点约为1。     

用光谱法研究异鼠李素与牛血清白蛋白的相互作用及几种金属离子对反应的影响

用紫外光谱法、 荧光光谱法研究异鼠李素与牛血清白 蛋白的相互作用机理及几种金属离子与异鼠李素和牛血清白蛋白之间的相互作用, 并探讨了几种金属离子与异鼠李素结合的类型, 阐明了它们的结合产物对牛血清白蛋白的作用机理. 实验结果表明, 异鼠李素与牛血清白蛋白主要是凭借静电引力作用结合, 异鼠李素主要以静态猝灭方式使牛血清白蛋白荧光强度减弱. 金属离子的介入影响了异鼠李素与牛血清白蛋白 的结合, 降低了其结合能力.     

铜离子存在下依诺沙星与牛血清白蛋白的相互作用研究

应用荧光光度法研究了生理条件下依诺沙星与牛血清白蛋白相互作用机制．实验结果表明,依诺沙星和牛血清白蛋白主要凭借疏水作用力结合,依诺沙星主要以静态猝灭的方式使得牛血清白蛋白荧光强度显降低．探讨了铜离子及依诺沙星与牛血清白蛋白间相互竞争结合反应,阐明了铜离子浓度对依诺沙星和蛋白质结合的影响．     

山奈素与牛血清白蛋白的相互作用研究

血清白蛋白在哺乳动物体内起着重要的贮存和运输作用,它能与多种内源和外源性物质结合[1].研究药物特别是中药活性组分与血清白蛋白相互作用,探讨作用机理,为中药的发展与更有效的推广应用提供可靠的理论依据;通过研究各种条件对血清白蛋白的影响,为合理给药提供理论依据[2].本文利用光谱法研究了溶液体系中山奈素与牛血清白蛋白的相互作用,初步探讨了山奈素与牛血清白蛋白两者之间的相互作用.     

阿昔洛韦与牛血清蛋白相互作用研究

目的研究了阿昔洛韦(ACV)与牛血清白蛋白(BSA)之间的相互作用。方法在pH为7.4的Tris-HCl缓冲液中,发现阿昔洛韦在348 nm(λex=282 nm)对牛血清白蛋白的荧光有猝灭作用。并对阿昔洛韦对牛血清白蛋白荧光猝灭的机理进行了初步探讨。结果发现在弱酸性、中性及弱碱性条件下均表现为静态猝灭。利用荧光猝灭双倒数图计算了阿昔洛韦与牛血清白蛋白之间的表观结合常数为1.48×10~4、结合位点数为1,结合位置接近于色氨酸残基,牛血清白蛋白中色氨酸残基与阿昔洛韦分子间的距离为3.138 nm。结论根据热力学参数计算确定了阿昔洛韦与牛血清白蛋白之间的主要作用力类型为疏水作用力,同时,采用同步荧光技术考察了阿昔洛韦对牛血清白蛋白构象的影响。     

光谱法研究EDTA-Fe(Ⅲ)与牛血清白蛋白的相互作用

应用紫外光谱法和荧光光谱法研究了乙二胺四乙酸铁(Ⅲ)(EDTA-Fe(Ⅲ))与牛血清白蛋白的相互作用.结果表明:EDTA-Fe(Ⅲ)可以进入牛血清白蛋白的疏水腔,使蛋白质非极性区的生色基暴露于极性溶剂;EDTA-Fe(Ⅲ)通过静态猝灭的方式使牛血清白蛋白的荧光强度显著降低;EDTA-Fe(Ⅲ)与牛血清白蛋白主要以氢键和范德华力相结合.测定了EDTA-Fe(Ⅲ)与牛血清白蛋白的结合常数KA和结合位点数n,利用Forster非辐射能量转移机制确定了牛血清白蛋白与EDTA-Fe(Ⅲ)的结合距离和能量转移效率,并使用同步荧光技术探讨了EDTA-Fe(Ⅲ)对牛血清白蛋白构象的影响.     

探针曲克芦丁测定蛋白质的实验研究

曲克芦丁是临床上治疗闭塞性脑血管病的常用药物,能够与牛血清白蛋白（BSA）相互作用生成复合物,进而导致牛血清白蛋白的内源荧光发生特异性变化;曲克芦丁与牛血清白蛋白体系的同步荧光光谱强度和牛血清白蛋白的浓度呈良好的线性关系,因而提出建立以曲克芦丁为荧光探针,用固定波长同步荧光光谱分析测定牛血清蛋白质的方法。结果表明,在最佳实验条件下,体系的同步荧光强度与牛血清白蛋白的浓度在0.5×10-6～7.5×10-6 mol·L-1范围内呈现良好的线性关系,这种良好的线性关系为检测蛋白质含量提供了一种新的测试手段。     

荧光光谱法研究羟基化单壁碳纳米管与牛血清白蛋白/血红蛋白的相互作用

纳米材料与蛋白质等生物大分子的相互作用是纳米材料生物安全性的重要内容。为了解羟基化单壁碳纳米管与牛血清白蛋白/血红蛋白的相互作用特点,选择两种不同长度的羟基化单壁碳纳米管(Short-SWNTs-OH、Long-SWNTs-OH),利用荧光光谱法和同步荧光光谱法分别分析在生理条件下它们与牛血清白蛋白/血红蛋白的相互作用。荧光光谱显示,两种羟基化单壁碳纳米管可以猝灭牛血清白蛋白和牛血红蛋白的内源荧光,且猝灭效应随碳纳米管的浓度增大而增强,对牛血清白蛋白,Short-SWNTs-OH的荧光猝灭作用强于Long-SWNTs-OH;Short-SWNTs-OH和Long-SWNTs-OH对牛血红蛋白的荧光猝灭作用相差不大;同步荧光光谱显示,Short-SWNTsOH对牛血清白蛋白的色氨酸残基(Trp)荧光猝灭作用强于酪氨酸残基(Tyr)。实验结果表明,碳纳米管的形貌特征及蛋白质的类型对碳纳米管与蛋白质的相互作用存在一定的影响:与牛血红蛋白相比,羟基化单壁碳纳米管更易于和牛血清白蛋白结合,羟基化单壁碳纳米管的长度、蛋白质的类型对它们之间的相互作用存在一定的影响,两种碳纳米管与牛血清白蛋白的作用位置更接近色氨酸残基。该工作可为全面评价包括碳纳米管在内的纳米材料的生物安全性提供参考。     

红霉素与牛血清白蛋白的相互作用机制

利用荧光及紫外光谱法研究了水溶液体系中红霉素与牛血清白蛋白(BSA)的相互作用机制.结果表明红霉素对牛血清白蛋白的荧光有较强的猝灭作用,其猝灭类型主要为静态猝灭.在不同温度下求得了红霉素与牛血清白蛋白的结合常数K,发现随反应温度上升K值下降.由热力学参数确定了红霉素与牛血清白蛋白的结合作用主要为范德华力.又根据Frster理论,测得了红霉素与牛血清白蛋白结合的能量转移效率,相互结合距离和结合位点.进一步证明了该反应是单一静态猝灭过程,阐述了其猝灭机理是通过能量转移产生的.     

1,4,7-三氮杂环壬烷合钴与牛血清白蛋白的相互作用

利用荧光光谱法研究了1,4,7-三氮杂环壬烷合钴(Ⅱ)与牛血清白蛋白的相互作用,实验结果表明1,4,7-三氮杂环壬烷合钴(Ⅱ)对牛血清白蛋白的荧光猝灭是静态猝灭,并得出在水溶液和胶束溶液中1,4,7-三氮杂环壬烷合钴(Ⅱ)与牛血清白蛋白作用的结合点位数、结合常数和热力学参数,△H0,△S0,其分子间的作用力主要表现为疏水作用力.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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