Application of NMR-Spectroscopy to Retinal Proteins

The application of NMR spectroscopy to the retinal proteins bacteriorhodopsin (BR) and rhodopsin is reviewed. ²H-, ¹⁵N-, and ¹³C-solid-state NMR spectroscopy have contributed considerably to understanding the conformation and chemical environment of the protonated retinylidene Schiff base in BR as well as in rhodospin. The data from both pigments clarified the mechanism of the opsin shift which is quite different for rhodopsin and BR. An analysis of the chemical shifts of isotopically labeled aspartic acid, tyrosine, and proline incorporated into BR-provided evidence for the protonation state of Asp and Tyr, and the isomerization state of the Xaa—Pro peptide bond, respectively. Solid-state NMR spectroscopy was also applied to the investigation of the photocycle intermediates of BR, as well as bathorhodopsin and metarhodopsin II, which are formed after light-activation of rhodopsin. Solution NMR spectroscopy of BR solubilized in detergents or organic solvents, as well as of opsin-derived peptide segments, was also applied to the investigation of the two- and three-dimensional structure of BR.     

拉曼光谱技术在玻璃材料研究中的应用

拉曼光谱分析技术是一种无损原位检测技术,具有检测速度快、收集信息丰富、对结构变化敏感等特点,在玻璃材料表征研究方面具有很大优势。本文综述了拉曼光谱的特点及其在玻璃结构研究方面的研究进展。     

The Application of Raman Spectroscopy to Surface Chemical Studies

Recent developments in instrumentation have led to the renaissance of Raman spectroscopy. Initial studies have shown that the technique may be used successfully to study surface chemical problems and it now seems appropriate to review these initial studies. The intent of this review is to help new workers in the field and to indicate some of the powers and limitations of the method.     

在线拉曼光谱的应用

与传统的表征方法相比,光纤探头和光谱仪构成的在线拉曼测量系统,以采样简单,检测速度快等特点广泛应用于各个领域。本文介绍了在线拉曼特点,分析了使用其测量的优势和由使用探头而带来的劣势,简述了该技术在石油化工业,高分子材料等中的实例应用。     

药物分析中的拉曼光谱技术应用研究

分析了拉曼光谱技术的应用原理及其分类,重点论述了拉曼光谱技术及其在药物分析中的应用发展,为药物分析检测提供技术支持,对提升药物分析能力和分析结果的准确性具有积极的现实意义。     

拉曼光谱分析技术在汽油调和系统中的应用

针对汽油调和系统的实际需要,研制开发了一套在线拉曼光谱分析系统。该系统应用于实际汽油调和装置,实现了对汽油研究法辛烷值、氧含量及芳烯烃含量等指标的在线分析。通过长时间的运行表明:系统符合设计要求,研究法辛烷值等分析数据能够快速反映调和装置操作条件的变化,可以为工艺装置的操作优化提供准确而重要的检测参数。     

拉曼光谱检测甲基苯丙胺类毒品的应用研究

选择拉曼光谱法对甲基苯丙胺类毒品及其混合物以及擦取了少量冰毒混合物的面包、馒头载体进行分析测试,希望可以对甲基苯丙胺类毒品的检验提供理论支持。     

Application of Artificial Pigments to Structure Determination and Study of Photoinduced Transformations of Retinal Proteins

The protonated Schiff bases of all-trans-retinal and its double bond isomers, 11-cis- and 13-cis-retinals, comprise the chromophores of bacteriorhodopsin, sensory rhodopsin, rhodopsin, and the Chlamydomonas photoreceptor pigment. Absorption of photons by these chromophores is directly responsible for the functioning of the various photopigments. Clarification of their extremely complex structures and mechanisms requires multidisciplinary collaboration. The study of synthetic retinal analogs and pigments reconstituted from analogs provides a powerful and indispensable tool for such clarification. This article summarizes the application of retinal analogs in the bioorganic, biophysical, and biochemical investigations of the various retinal pigments.     

Sequences and Structures of Retinal Proteins

The past few years have been an exciting period in the field of the structure of retinal proteins, especially the visual pigments. A significant achievement is the 9 Å projection map of bovine rhodopsin. This not only provides knowledge of the three-dimensional structure of visual pigments, but also establishes a more reliable basis for the structural modeling of all the G-protein-coupled receptors. The modeling of such three-dimensional structures will eventually lead to a better understanding of the function of visual pigments and other G-protein-coupled receptors. Our goal in this article is to draw attention to recent developments in the structure of retinal proteins, with special emphasis on visual pigments. By combining a wide range of existing experimental data with the results of theoretical calculations, a new three-dimensional structure of visual pigments, which differs from the models which have so far been reported, is proposed.     

拉曼光谱在检测饮用水中微塑料的应用

微塑料污染引起越来越多的关注。通过显微拉曼光谱检测饮用水中的微塑料,结果表明,所测饮用水中未检出粒径大于0.22μm的微塑料;在室温使用条件下,PET瓶也不会迁移出大量微塑料。对拉曼谱图主要特征峰分析后建立一个适合于微塑料分析的参考数据库,结合显微镜成像技术为微塑料的鉴定和定量提供了一条新途径。随着光谱分析技术的发展,标准化的检测操作流程是未来的发展方向。本研究的光谱分析方法为系统地了解微塑料污染情况提供了数据支持。     

拉曼光谱及其在癌症检测中的应用

简述了拉曼光谱的原理、特点及应用,重点介绍了其在在癌症检测和诊断中的应用。     

小波变换在Raman汽油辛烷值测定仪中的应用

将小波变换技术应用到Raman汽油辛烷值测定仪的数据预处理中,减弱荧光背景干扰和高频噪声,提高光谱数据的信噪比。实验结果表明,小波变换对汽油Raman光谱的数据预处理比二阶微分、背景趋势消除技术的预处理效果好,显著提高基于偏最小二乘方法建立的汽油辛烷值预测模型精度。     

红外光谱和拉曼光谱法研究白炭黑的微观结构

用红外光谱和拉曼光谱分析沉淀法白炭黑和气相法白炭黑的微观结构。结果表明：与气相法白炭黑相比,沉淀法白炭黑表面羟基含量相对较高;未经热处理的沉淀法白炭黑表面覆盖结合水分子,随着处理温度的升高,沉淀法白炭黑表面先失去羟基结合水分子,然后发生羟基缩合反应,直至最后失去所有羟基,形成Si—O—Si网络结构;气相法白炭黑未经热处理时即可明显观察到羟基的存在,且处理温度对其结构影响不明显,这可能是沉淀法白炭黑与气相法白炭黑生产工艺不同造成的。     

Raman Spectroscopy of Tetragonal Zirconia Solid Solutions

Raman spectra of tetragonal zirconia were studied for the systems ZrO₂-Y₂O₃, ZrO₂-CeO₂, ZrO₂-Y₂O₃-Nb₂O₅, and ZrO₂-Y₂O₃-Ta₂O₅ There was no change in the Raman bands for tetragonal ziraconia in the ZrO₂-Y₂O₃ system as a function of Y₂O₃ content . On the other hand, in the ternary systems, the Raman lines corresponding to the stretching modes of two sets of cation-oxygen bonds shifted to greater wave numbers as either Nb₂O₅ Contents increased in Y₂O₃-stabilized tetragonal zirconia. This difference was interpreted by local bonding environments of the pentavalent cations, which were supposed to occupy tetrahedral sites in teteragonal zirconia solid solutions.     

几种塑料的拉曼光谱检测

应用拉曼光谱技术,对食品包装用几大类塑料材料进行了检测和分析.获得了聚对苯二甲酸乙二醇酯、聚乙烯、聚氯乙烯、聚丙烯、聚苯乙烯、聚碳酸酯的标准拉曼光谱.通过将实际检测样品和数据库中标准拉曼光谱的对比,可以快速准确地鉴定出检测样品的种类.同时该技术具有对检测样品无损和直接检测的优点.     

Uses of Raman Spectroscopy in Cement Chemistry

Laser-Raman spectroscopy is largely complementary to ir spectroscopy, but spectral interpretation is simpler. Lack of homogeneity in clinker minerals, direct study of white portland cement hydration, characterization of clinker minerals, identification of the various calcium sulfate forms, and effects of carbonation are discussed.     

Characterization of Multicomponent Aerosols by Raman Spectroscopy

In this work the feasibility of Raman spectroscopy, especially the detection limit of this technique for the chemical characterization of multicomponent aerosols, which appear in technical processes has been investigated. In such kind of aerosols high number concentrations (>10⁶ cm^?3) can be observed whereas the range of the pollutant loading varies from 10–1000 mg/m³. For these purposes different type of aerosols have been investigated. Aerosols in which the pollutant can be found in the dispersed phase as well as in the gas phase (aqueous solutions of NH₃ aerosols), those where the pollutant appears only in the dispersed phase (aqueous solutions containing SO₄ ^2?/ NO₃ ^? salts) and aerosols where there is no Raman shift between the signals of the gas and the dispersed phase (toluene/ dodecane aerosols). Furthermore aerosols generated by the reaction between NH₃ and HCl in nitrogen containing different amounts of vapor are also investigated.

The characterization of the aerosols with Raman spectroscopy with respect to their gas phase is without any difficulty, whereas the analysis in the dispersed phase is partially marginal and in majority of cases almost not possible.

Especially for the reaction aerosols rejection of elastically scattered light is the principle limitation in collecting Raman scattered light from particles in the Mie-scattering regime.     

Engineering Nanostructures for Single-Molecule Surface-Enhanced Raman Spectroscopy

Surface-enhanced Raman spectroscopy (SERS), an effect discovered in the 1970s and studied systematically in the 1980s, received a significant “second wind” with the report (primarily by Nie and by Kneipp) of enhancements large enough to allow the Raman spectrum of single molecules to be obtained. It is now understood that this occurs as a result of the extremely high electromagnetic fields that can exist at appropriately configured gaps and interstices between nanoparticles and other nanostructures composed of suitable materials (such as silver). With this insight one is now in a position to fabricate structures that will dependably and repeatably produce single-molecule SERS. We describe three such strategies: using molecular linkers to self-assemble silver clusters possessing the correct geometry; fabricating nanowire rafts in which the gaps between nanowires are “hot”; and structuring the interior of nanopores so as to produce finely-architectured nanostructured arrays.     

Candida parapsilosis Biofilm Identification by Raman Spectroscopy

Colonies of Candida parapsilosis on culture plates were probed directly in situ using Raman spectroscopy for rapid identification of specific strains separated by a given time intervals (up to months apart). To classify the Raman spectra, data analysis was performed using the approach of principal component analysis (PCA). The analysis of the data sets generated during the scans of individual colonies reveals that despite the inhomogeneity of the biological samples unambiguous associations to individual strains (two biofilm-positive and two biofilm-negative) could be made.     

利用拉曼光谱法检测饮料中的甲基苯丙胺

利用拉曼光谱技术建立了快速检测饮料中甲基苯丙胺的方法.对市场出售的可乐、脉动、橙汁三种饮料进行甲基苯丙胺不同加标浓度的表面增强拉曼光谱检测,结果表明加标饮料的拉曼光谱对比未加标饮料出现了明显的变化,在991 cm-1、1016 cm-1,1201 cm-1处出现了强烈的拉曼信号,这些特征稳定存在,可以作为鉴定此3种饮料...