热致型液晶聚合物的近晶相结构研究

本文借助于不同热处理样品的WAXD研究和变温FTIR分析,从液晶态与结晶态面间距的变化,晶态、液晶态和各向同性液态下结构构象的差异出发,研究了聚合物液晶态下的近晶相结构模型。     

含两种不同介晶基团的半刚性共聚酯液晶态的结构研究

用Ｘ－光衍射，偏光显微镜及ＤＳＣ对含两种不同长度介晶基团４，４’－联苯二酚（Ⅰ）和对苯二甲酸二（对羟苯基）酯（Ⅱ）的系列共聚酯的液晶态进行了表征，据其液晶态中两种介晶单元的堆砌方式提出了可能的模型，这种模型很好地解释了液晶态的Ｘ－光衍射分布．     

高分子液晶态有序性对基结晶过程的影响

采用退偏振光强度法、SALS和POM测定了高分子液晶态有序微区结构随体系温度变化的规律，并用DSC法研究具有不同有序微区结构尺寸的液晶态的结晶过程。结果发现，高分子液晶态有序性或有序微区结构是随着体系退火温度和时间的变化而变化。同时从相应的不同有序性为起始态进行结晶时，其结晶速率明显不同，并讨论了高分子液晶态的结晶机理。     

液晶态分子在分析化学中的应用进展

评述了液晶态分子在分析化学中的应用进展，包括其超分子的分子识别作用，液晶在色谱，光谱探针，核磁共振谱等分析化学领域中的应用。     

手征性侧链液晶高分子取向结构的研究

用偏光显微镜,红外二色性和Ｘ 射线衍射研究了一种手征性侧链液晶高分子的相态织构和弛豫行为．偏光显微镜观察这种侧链液晶高分子冻结取向液晶态薄膜时,可观察到与剪切方向垂直的明暗相间的条带织构．红外二向色性的结果表明,取向态中侧链上的介晶基元倾向于与剪切方向垂直排列．取向和非取向膜的Ｘ射线衍射揭示了该侧链液晶高分子具有反铁电性液晶的两套反相螺旋结构．取向薄膜在液晶态的弛豫行为表明,取向作用能促进侧链高分子近晶相层状结构的生长,而且介晶基元的取向在弛豫过程中能保持下来．     

乙基氰乙基纤维素／聚丙烯酸复合物及大分子胆甾型液晶相的形态结构特征

对乙基氰乙基纤维素／丙烯酸胆甾型液晶溶液的液晶性，液晶态的织构特征，丙烯酸在液晶溶液中的聚合反应及在反应过程中胆甾型液晶相结构和性能的变化等方面进行了研究，     

抗癌药物与DNA作用的电化学研究进展

针对当前电化学研究领域中的热门课题——DNA的电化学研究，阐述了与DNA的电化学研究相关的理论基础，其中包括作用机理和作用模式等，概述了其近几年的研究进展，并在此基础上对抗癌药物与DNA的相互作用的电化学研究工作特别是该研究的潜在应用，即抗癌药物的新型筛选方法——电化学筛选方法进行了介绍。     

几类非常规液晶材料的研究进展

本文综述了液晶二聚体、多爪型液晶及香蕉形液晶等几类非常规液晶材料的研究进展。结合笔者近几年的研究积累,着重介绍:(1)液晶二聚体的分子结构与液晶态结构及液晶二聚体所特有的奇偶效应与近晶多形性;(2)多爪型液晶的分子结构与液晶态结构的特点及由于兼有棒状分子与盘状分子的结构特点而具备的特殊的相变性质;(3)香蕉形液晶的分子结构与液晶态结构及香蕉形液晶所特有的手性与极化序。在介绍各类液晶材料的特点及研究热点的同时,围绕分子结构与液晶态结构的关系这一主题,深入讨论了各种液晶材料形成特殊分子排列及表现出特殊物理性质的机理。     

新型液晶／高聚物复合膜的富氧性能及结构表征 Ⅱ．液晶／高聚物复合膜的结构表征

用ＩＲ、ＤＳＣ、ＷＡＸＤ、正交偏光显微镜、ＳＥＭ、ＴＥＭ等手段，表征了所合成的液晶／烃橡胶、硅橡胶三元共混复合膜的织态结构及液晶态转变，结果发现，液晶ＰＥＥＣＢ－４．０５由于与ＳＢＲ和ＰＤＭＳ共混，Ｔｋ－ｓ转变温度下降了３７．５℃，体系存在不完全的相分离，液晶ＰＥＥＣＢ－４．０５在体系中形成液晶富集区（ＬＣ－ｒｉｃｈ ｄｏｍａｉｎ），大小约０．２－２．２μｍ，在压力的作用下，连续的液晶富集区形成宽     

化学物质与生物膜相互作用的液晶态构象研究

采用近代物理技术对化学物质与生物膜相互作用的液晶态构象进行了研究.结果表明:在外界环境的影响下,生物膜的液晶态可以从双层相变成非双层相.这些非双层相除常见的立方相、六角形相外,还存在一些更复杂的中间相,即片层立方相、片层六角相和立方六角相结构.实验发现,化学物质有使生物膜的液晶态趋于形成非双层相的作用.其离子半径、分子间van der Waals力、静电力、以及pH值的大小对生物膜的液晶态结构都有一定的影响     

Conformation of liquid crystalline state in interaction between chemical materials and biomembrane in terms of modern physics

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透析-高效液相色谱法在当归补血汤药效物质基础研究中的应用

将脂质体作为模拟生物膜,采用平衡透析与液相色谱联用技术,建立了一种研究中药成分与模拟生物具有相互作用的新方法。应用该方法对当归补血汤进行了分析,同时考察了模拟生物膜的浓度、pH值、缓冲系统和胆固醇的加入等因素对当归补血汤与模拟生物膜相互作用的影响。结果表明:当归补血汤中有7个组分与模拟生物膜相互作用明显;模拟生物膜的浓度影响最大,pH值对酸性组分阿魏酸的作用影响较大,其它因素的影响较小。该方法可用于预测药物在体内的吸收情况,进而研究中草药及复方的药效物质基础。     

Dynamic molecular movements and aggregation structures of lipids in a liquid state

This paper discusses the molecular conformations and the liquid structures of triacylglycerols (TGs) and fatty acids in their melts. Three models for liquid state ordering have been proposed for TG melts to date: the smectic liquid crystal model, the nematic liquid crystal model, and the discotic model. To completely resolve the liquid structure of TGs, further research is required. However, some information on the molecular level has been obtained for fatty acids that are relatively simple compounds. The combination of various spectroscopic and thermodynamic measurements revealed that the hydrogen-bonded dimers of fatty acids are units of intermolecular and intramolecular movements in the liquids and in non-polar solvents. The dimers that construct the clusters resemble the smectic liquid crystal and determine the physicochemical properties of the liquid of the fatty acid. Cholesterol stabilizes the clusters, while ethanol destroys them. Self-diffusion and neutron diffraction measurements revealed that two kinds of fatty acids exist in their binary liquid mixture exist as the homodimers composed of same species.     

Calorimetric evaluation of the interaction and absorption of eicosapentaenoic acid by biomembrane models

The interaction of eicosapentaenoic acid, a polyunsaturated fatty acid belonging to the omega-3 class, with biomembrane models represented by multilamellar or unilamellar vesicles made of dimyristoylphosphatidylcholine was monitored by means of differential scanning calorimetry technique. The calorimetric analysis of vesicle prepared in the presence of increasing molar fraction of eicosapentaenoic acid was carried out to show its maximum interaction with biomembrane models evaluating the effects of eicosapentaenoic acid on the biomembrane models thermotropic parameters (transition temperature and enthalpy variation). Furthermore, in order to detect the influence of the presence of hydrophilic or lipophilic media on the entity of the compound absorption by the biomembrane models, kinetic experiments were carried out.The results indicate that eicosapentaenoic acid strongly interacts with the biomembrane models depressing the transition temperature and the enthalpy variation. Eicosapentaenoic acid is absorbed by the biomembrane models and the absorption is affected by the used medium; in fact a bigger absorption happens in the presence of a lipophilic medium.     

Effect of surfactant phase transition on the inclusion behaviour of an amphiphilised porphyrin derivative

The macroscopic morphology of a micelle biomembrane model strongly affects the aggregation state of an included porphyrin derivative.     

Voltammetric study of levomepromazine induced ionic permeability in a model lipid membrane system

The interaction of solid supported liquid films of lipids with levomepromazine is investigated in the present work by voltammetry. It is shown that the levomepromazine penetrates into the films, which results in a readily detectable change of the film permeability to electroactive species. In this respect, possibilities for the employment of supported lipid films as model systems in the research of biomembrane active compounds are briefly discussed.     

Dynamic behaviors of molecular assemblies at liquid/liquid interfaces studied by time-resolved quasi-elastic laser scattering spectroscopy.

The dynamic behaviors of molecular assemblies at two immiscible liquid interfaces are intriguing topics in many fields of science and technology. However, it is generally difficult to investigate the dynamic behaviors of such molecular assemblies because of the buried nature of liquid/liquid interfaces. In the present paper, our recent investigations on dynamic behaviors of various molecular self-assemblies at liquid/liquid interfaces are reviewed. We monitored dynamic behaviors of the molecular assemblies by time-resolved quasi-elastic laser scattering (TR-QELS) and fluorescent spectroscopy. The former method allows us to monitor the change in interfacial tension with millisecond time-resolution. As molecular assemblies, bis(2-ethylhexyl)sulfosuccinate (AOT) microemulsion, phospholipid biomembrane models, and liposome-DNA complexes have all been studied, since they are relevant in material sciences and biological technologies. At liquid/liquid interfaces, these molecular assemblies showed characteristic behaviors. We review the finding of rebound response of the interfacial tension at the liquid/liquid interface induced by the adsorption of the AOT microemulsion. We monitored the hydrolysis reaction of phospholipid biomembrane models formed at oil/water interfaces, observing the different types of behavior of liposome-DNA complexes at biomembrane models with different kinds of phospholipids.     

Amphotericin B-phospholipid covalent conjugates: dependence of membrane-permeabilizing activity on acyl-chain length

The interaction between amphotericin B and phospholipid upon forming ion channels across a biomembrane was investigated using their covalent conjugates. The membrane permeabilizing activity was greatly affected by the chain length of the fatty acyl groups, suggesting that their interaction is involved in ion channel assemblages.     

脂肪酸量子化学特性对食用油脂生物学效应的影响

对一些食用油脂中的主要脂肪酸组份的量子化学参数进行计算，并与饲喂大鼠的相应生物学效应进行相关分析的结果表明，在各项大鼠血脂生化指标中，只有血清总胆固醇（TC）和低密度脂蛋白-胆固醇含量与脂肪酸各项量子化学参数间存在显著性相关（P＜0．05），其中单不饱和脂肪酸（MUFA）的效果优于多不饱和脂肪酸（PUFA）。MUFA还可有效降低机体丙二醛含量，增强生物膜的流动性（P＜0．01）．不饱和脂肪酸分子中烯键碳原子上量子化学参数的急剧变化是油脂产生显著生物学效应的基本条件．     

Photoionization of Oxidized Coenzyme Q in Microemulsion: Laser Flash Photolysis Study in Biomembrane‐like System

Photoexcitation to generate triplet state has been proved to be the main photoreaction in homogeneous system for many benzoquinone derivatives, including oxidized coenzyme Q (CoQ) and its analogs. In the present study, microemulsion of CoQ, a heterogeneous system, is employed to mimic the distribution of CoQ in biomembrane. The photochemistry of CoQ₁₀ in microemulsion and cyclohexane is investigated and compared using laser flash photolysis and results show that CoQ₁₀ undergoes photoionization via a monophotonic process to generate radical cation of CoQ₁₀ in microemulsion and photoexcitation to generate excited triplet state in cyclohexane. Meanwhile, photoreactions of duroquinone (DQ) and CoQ₀ in microemulsion are also investigated to analyze the influence of molecular structure on the photochemistry of benzoquinone derivatives in microemulsion. Results suggest that photoexcitation, which is followed by excited state‐involved hydrogen‐abstraction reaction, is the main photoreaction for DQ and CoQ₀ in microemulsion. However, photoexcited CoQ₀ also leads to the formation of hydrated electrons. The isoprenoid side chain‐involved high resonance stabilization is proposed to explain the difference in photoreactions of CoQ₀ and CoQ₁₀ in microemulsion. Considering that microemulsion is close to biomembrane system, its photoionization in microemulsion may be helpful to understand the real photochemistry of biological quinones in biomembrane system.