共查询到20条相似文献,搜索用时 125 毫秒
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分子印迹技术是将分子设计、大分子合成、分子识别、生物模拟以及生物工程等技术的优点结合起来发展而成的一种新兴跨学科方法,所形成的分子印迹聚合物亲合性好、选择性和稳定性高。二氧化钛及其复合材料价格低廉、安全高效、绿色环保、光催化活性高,被广泛应用于光催化、光电转换等领域。二氧化钛及其复合材料形成的分子印迹聚合物稳定性高,光催化活性好,并且具有良好的选择性,能对低浓度、高毒性污染物进行选择性富集及光催化降解,拓宽了其应用范围。本文综述了近二十年来分子印迹型二氧化钛及其复合材料的制备方法及其在光催化降解、传感器构建以及其他领域的应用概况,并进行展望。 相似文献
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分子容器是一种可以模仿酶的受限空间以及活性位点的超分子结构,自从出现以来引起了超分子科学家的广泛兴趣.科学家们开发了具有不同大小及电性的分子容器,以期望其在反应中间体稳定、活性物种捕获以及催化反应等领域具有应用价值.主要综述了超分子领域广泛关注的几种作为阳离子受体的分子容器,它们通过对阳离子物种的包裹从而实现稳定活性物种、调节反应活性以及提升底物/反应选择性的目的.以分子容器的功能分类,对分子容器的识别行为及其对阳离子物种性质的调控功能进行总结,阐释其中的原理和规律并对该领域未来的发展进行展望. 相似文献
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A reversed-phase high-performance liquid chromatographic (HPLC) analysis of bile pigments is described that provides baseline separation of the major bilirubin conjugates found in bile. The advantage of the technique is that the bile pigments can be analyzed directly as their native tetrapyrroles without prior solvent extractions or derivatization. The use of ammonium acetate in place of sodium salts permits preparative isolation and lyophilization of the pigments for mass spectroscopy. The derivatization of the pigments as their dipyrrolic azosulfanilates with subsequent HPLC analysis demonstrates baseline separation of the endo- and exovinyl azodipyrroles and allows identification of that half of the tetrapyrrole which contains the conjugate in the instances of monoglycosides. 相似文献
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Heinz Falk Thomas Schlederer Peter Wolschann 《Monatshefte für Chemie / Chemical Monthly》1981,112(2):199-207
The long standing problem of solvent dependent absorption spectra of certain bile pigments such as bilirubindimethylester has been solved by measurement of molecular masses by means of vapour pressure osmometry. Using this method and the investigation of the concentration and temperature dependence of the absorption spectra on several model compounds an association equilibrium for pigments of the rubinoid structural type could be confirmed. Moreover the optical properties of the coexisting species and the corresponding equilibrium constants could be deduced by spectroscopic techniques. Verdinoid pigments lacking free carboxylic functions on the other hand tend to be monomeric in solution. A heteroassociated species involving equimolar amounts of a verdinoid and a rubinoid pigment could be verified existing on adsorbents like silicagel.
37. Mitt.:Falk, H., Thirring, K., Tetrahedron, im Druck. 相似文献
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Recent applications of thin-layer chromatographic (TLC) and high-performance liquid chromatographic (HPLC) procedures has revealed an unexpected wide variety of naturally occurring unconjugated and conjugated bilirubins. Biliverdins seems to occur only in unconjugated forms, mainly as the IX alpha isomer. Several synthetic biliverdins and bilirubins present interesting models for biochemical and metabolic studies. Owing to recent recognition of the astounding heterogeneity of natural bilirubins and to the various artifactual changes that bile pigments can undergo, considerable confusion has existed, and still exists, with regard to the nomenclature of the bile pigments and their derivatives. To set a background for further discussion, the present review starts with a brief discussion of nomenclature and of the various characteristic forms of lability of the bile pigments. TLC and HPLC procedures for preparation and analysis of unconjugated biliverdins and bilirubins and their methyl ester and sugar ester conjugates, as well as procedures for analysis of bilirubin-protein conjugates, are then discussed. Since, in view of the lability and pronounced heterogeneity of bile pigments, it is important to assess the composition and nature of chromatographically isolated pigments, the review is concluded by a brief evaluation of various structural tests. 相似文献
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Hugo Scheer 《Angewandte Chemie (International ed. in English)》1981,20(3):241-261
Biliproteins, covalently bonded complexes of proteins and bile pigments, serve as light-harvesting pigments in photosynthesis and light-sensory pigments of photosynthetic organisms. Recent developments in the biochemistry and biophysics of these pigments are reviewed and an attempt is made to describe their functions of light-harvesting and of information transduction on a molecular level. 相似文献
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The carrier mediated transport of cations using model compounds of the verdinoid and rubinoid bile pigment structural type as ionophores is studied. Verdinoid bile pigments turn out to be very effective carriers for cations exhibiting a pronounced selectivity for certain transition metal ions like Cr+-+, Fe++, Cu++ and Zn++. The scope of this behaviour of verdinoid bile pigments is compared to [18]-crown-6 and meso-tetraphenylporphin and is discussed with regard to structural, biological, analytical and technical implications. 相似文献
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Heinz Falk Günther Höllbacher Otmar Hofer Norbert Müller 《Monatshefte für Chemie / Chemical Monthly》1981,112(3):391-403
A force field model was designed with respect to the special needs of bile pigments. It is parametrized and tested using partial structures of bile pigments as well as an integral pigment; the solution structures of the molecules were previously deduced using independent experimental methods.
38. Mitt::Falk, H., Schlederer, T., Wolshann, P., Mh. Chem.112, 199 (1981). 相似文献
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Heinz Falk Günther Höllbacher Otmar Hofer 《Monatshefte für Chemie / Chemical Monthly》1979,110(4):1025-1027
A force field constructed for bile pigments and parametrized on partial structures of bile pigments was used to calculate the minimum energy geometries of diastereomeric bilatrienes-abc. In addition the relative energies of these isomers were deduced and the energies of interconversion between the mirror images of the more or less helical (Z,Z,Z)-syn, syn, syn-form were calculated for various paths. 相似文献
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In contrast to conventional pigments, which interact with light by absorption and/or diffuse scattering, effect or luster pigments show optical properties that are due to specular reflection of light by aligned flaky particles. Their main property is goniochromaticity, i.e. the change of lightness and/or color hue with the viewing angle of the observer. The paper describes the different type of luster pigments, their optical properties and applications and manufacturing methods. 相似文献
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A method for the separation and quantitation of ethyl anthranilate or p-iodoaniline azo derivatives of bile pigments was developed using reversed-phase high-performance liquid chromatography. A convenient separation was achieved in 15 min, permitting the quantitation of the unconjugated azo-dipyrrole (alpha o) and its glucuronide (delta), xyloside (alpha 2) and glucoside (alpha 3) conjugates. The pathological beta- and gamma-azo pigments, derived from bilirubin glucuronide isomers that occur in cholestatic bile or plasma, are also detected in this system. The results of this method as applied to bile from 25 healthy dogs were in excellent agreement with the values obtained by reversed-phase chromatography of bilirubin and its mono- and dimethyl esters produced from the corresponding conjugates by alkaline methanolysis. This system permits the sensitive and convenient determination of bilirubin and its conjugation pattern in biological fluids. 相似文献
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Abstract— Irradiation of 20-chloro-chlorophylls of the a-type with visible light produces long-wavelength shifted photoproducts, which transform in the dark to linear tetrapyrroles (bile pigments). The possible significance for chlorophyll degradation is discussed. 相似文献