光谱法研究盐酸麻黄碱及盐酸伪麻黄碱与人血清白蛋白的键合

在模拟人体生理条件下,采用紫外光谱法、荧光光谱法和同步荧光光谱法研究盐酸麻黄碱及盐酸伪麻黄碱与人血清白蛋白(HSA)的结合作用.实验表明:盐酸麻黄碱和盐酸伪麻黄碱对HSA的荧光猝灭机制均为静态猝灭,盐酸麻黄碱和盐酸伪麻黄碱与HSA均形成1∶1复合物,结合常数K分别为2.53×104 L·mol-1和2.02×104 L...     

一种减少基于SOA的全光时钟提取码型效应的新方法

全光位时钟提取是3R全光再生的关键技术,本文针对利用基于半导体光放大器注入锁模激光器进行位时钟提取时的码型效应,提出一种利用非线性偏振旋转自稳幅效应减少码型效应的新方法,对40Gb/s的半导体光放大器注入锁模激光器位时钟提取,通过数值模拟计算证明,利用非线性偏振旋转可以有效地减少码型效应的影响.     

同步镀铋膜差分脉冲伏安法测试土壤中铬

采用同步镀铋膜法修饰玻碳电极及差分脉冲溶出伏安法测试土壤中Cr。在优化的实验条件下,以KNO3为支持电解质,NaAc-HAc(pH=5.5)为缓冲溶液的铋膜上得到Cr溶出特征峰电位为-1.14V,线性方程为:I=0.0747C+0.31054,相关系数为0.9981,检出限为0.001μg/L,线性范围为0.01—60μg/L,RSD=2.47%,该方法简单快速,准确度和精密度均符合要求,回收率为96.7%—104.5%。     

光谱法研究葛根素与牛血清白蛋白的相互作用

采用紫外、同步荧光和圆二色光谱法研究了葛根素（PUE）与牛血清白蛋白（BSA）的相互作用.紫外光谱表明,BSA在230nm和278nm处的吸收峰,随着葛根素浓度的增加而减小.同步荧光光谱表明,葛根素引起BSA中色氨酸残基所处微环境的疏水性降低.圆二色光谱表明,BSA在208nm和222nm处的负峰随着葛根素浓度的增加而增强,BSA中α-螺旋含量也随之增加.这表明葛根素与BSA的相互作用,可使蛋白质分子的疏水作用增强,导致BSA的肽链结构收缩,蛋白质的构象发生变化.     

Interactions of Quercetin with Casein and Bovine Serum Albumin as well as the Effects of Coexisting Carbon Nanotubes

Fluorescence quenching and synchronous fluorescence methods were used to study the interactions of fluore-scence-active quercetin (Qct) with casein (Cas) and bovine serum albumin (BSA) in phosphate buffer solution (PBS, pH=7.4) with or without coexisting carbon nanotubes (CNTs). Formulae for binding constant (K) and molar binding ratio (n) were established for methods 1 (fixing protein concentration, changing Qct concentration, and monitoring the fluorescence of protein) and 2 (fixing Qct concentration, changing protein concentration, and monitoring the fluorescence of Qct), to which values of K and n were calculated via nonlinear least-square fitting of the experimental data, and the “optical inner filtering induced fluorescence quenching” effect was thus quantitatively evaluated. The quenching effects of coexisting CNTs on the fluorescence of Qct, BSA, and Cas, as well as the effects of coexisting CNTs on Qct-BSA and Qct-Cas interactions, were examined. Synchronous fluorescence was also used to examine the effects of coexisting CNTs and Qct on the conformations of BSA and Cas, with relevant K and n values for tyrosine (Tyr) and tryptophan (Trp) residues estimated. It was concluded that the CNTs mainly interacted with the Trp residues locating near the protein surfaces, but small-sized Qct molecules could further interact with the Tyr residues locating inside the protein molecules.     

Synchronous fluorescence spectroscopy and gas chromatography to determine the effect of UV irradiation on crude oil

The fate of the crude oil under irradiation was studied. After the UV irradiation, the fraction present in the highest percentage shifted from C8–C9 fraction to C13 one, in GC–MS analysis. An increase of the relative amount of the C13–C25 fraction was observed, while a decrease in the relative amount of the C7–C12 fractions was present. The synchronous fluorescence spectrum showed a maximum at 396 nm. Two hours irradiation of the sample induced an increase of the fluorescence emission in the region 420–550 nm. After 20, 40, 60, and 100 h irradiation we observed a decrease of the fluorescence emission.     

CdTe量子点同步荧光法测定人血清白蛋白

以巯基乙酸(HS-CH2COOH)为稳定剂,水相中合成了CdTe量子点.在pH 6.40的0.002 mol/L KH2PO4-Na2HPO4缓冲溶液中,固定波长差为220 nm时一定量蛋白质的加入能明显增强量子点的同步荧光强度,并且荧光峰强度增加值与血清白蛋白浓度间存在良好的线性关系,据此建立了一种高灵敏度的测定微量蛋白质的方法.该方法测定人血清白蛋白的线性范围为0.08～2.80 μg/mL,检出限为0.032 μg/mL,10次重复测定1.80 μg/mL的血清白蛋白相对标准偏差为1.1%,已用于实际样品的测定.     

荧光光谱法研究左西孟旦与牛血清白蛋白的结合反应

用荧光光谱法、分光光度法研究了水溶液中左西孟旦与牛血清白蛋白(BSA)的相互结合反应。研究表明:左西孟旦对BSA的内源荧光有较强的猝灭作用且该猝灭作用属于静态荧光猝灭作用。得出了反应的结合常数(KA=1.48×106L/mol)和结合位点数(n=1.14)。根据Frster非辐射能量转移机理,求算了给体(BSA)与受体(左西孟旦)间距离r=2.9 nm和能量转移效率E=0.33。     

Synchronous ultrasonic Doppler imaging of magnetic microparticles in biological tissues

We considered applicability of acoustic imaging technology for the detection of magnetic microparticles and nanoparticles inside soft biological tissues. Such particles are widely used for magnetically targeted drug delivery and magnetic hyperthermia. We developed a new method of ultrasonic synchronous tissue Doppler imaging with magnetic modulation for in vitro and in vivo detection and visualization of magnetic ultradisperse objects in soft tissues. Prototype hardware with appropriate software was produced and the method was successfully tested on magnetic microparticles injected into an excised pig liver.     

丙三醇存在下硫酸钡微粒体系的光谱特性研究及其分析应用

0.10 mol/L HCl-4.0 mol/L丙三醇-0.05 mol/L BaCl2溶液体系的瑞利散射很弱.当有SO4^2-存在时,（BaSO4）n微粒体系在470 nm处产生一较强的瑞利散射峰,SO4^2-浓度在1.0～80μg/mL浓度范围内与I470nm呈线性关系.据此,建立了一个测定水中硫酸根的简便、灵敏的瑞利散射光谱分析新方法.研究结果表明：SO4^2-与Ba^2＋由于静电引力可形成BaSO4分子,而BaSO4分子间存在较强疏水作用力和分子间作用力,可聚集形成（BaSO4）n微粒和固液界面,（BaSO4）n微粒和固液界面的形成是导致体系瑞利散射强的根本原因.