Detection of carbohydrate-binding proteins by oligosaccharide-modified polypyrrole interfaces using electrochemical surface plasmon resonance

This paper reports on the use of electrochemical surface plasmon resonance (E-SPR) for the detection of carbohydrate-binding proteins. The generation of an SPR sensor specific to lectins Arachis hypogaea (PNA) and Maackia amurensis (MAA) is based on the electrochemical polymerization of oligosaccharide derivatives functionalized by pyrrole groups. The resulting thin conducting polymer films were characterized using E-SPR and atomic force microscopy (AFM). The specific binding of PNA to polypyrrole-lactosyl and of MAA to polypyrrole-3'-sialyllactosyl films was investigated using SPR. The detection limit was 41 nM for PNA and 83 nM for MAA. Through Scatchard analysis and linear transformation of the SPR sensorgram data, association (k(ass)) and dissociation rate constants (k(diss)) could be determined.     

Estimating rate constants in a convection-diffusion system with a boundary reaction

While performing biomolecular interaction analysis (BIA), scientistsoften use surface plasmon resonance (SPR) to measure rate constantsof the associated reactions. A mathematical model of a BIAcore^TM,a common SPR device, consists of a convection-diffusion equationin a channel with a reacting surface at the channel ceiling.Asymptotic and singular perturbation techniques are used toanalyse the concentration of the reacting species in two cases:when the reaction occurs much more slowly than diffusion, andwhen the reaction occurs on the same time-scale as diffusion.Linear and nonlinear integral equations result from the analysis;explicit and asymptotic solutions are constructed for physicallyrealizable cases. These expressions provide a direct way toestimate the rate constants from raw data.     

Difference-frequency generation in PPLN at 4.25 μm: an analysis of sensitivity limits for DFG spectrometers

We report difference-frequency generation (DFG) in periodically poled lithium niobate (PPLN) around 4.25 μm using a cw Nd:YAG and an injection-locked diode laser. This system provides a narrow linewidth source at 4.25 μm with near-shot-noise-limited operation. A conversion efficiency close to the theoretical limit is obtained. Detection of CO₂ absorption spectra is demonstrated and further improvements and applications to high sensitivity spectroscopy are discussed. Received: 12 August 1999 / Revised version: 21 January 2000 / Published online: 24 March 2000     

一种新型四硫富瓦烯衍生物的合成与表征

以二硫化碳和金属钠为基础物质合成了四硫富瓦烯（TTF）锌的配合物（TTF）Zn（NBu4）2。利用该化合物与苯甲酰氯反应得到的稳定化合物C17H10O2S5在甲醇钠溶液中与2,3-二溴丙醇反应成功合成出目标化合物（一种新配体）,其化学组成为C6H6OS5。利用IR谱、^1HNMR谱及元素分析对此化合物进行了表征。     

新大线同沟敷设热力分析

针对新大线同沟敷设管道,采用非结构化有限容积法,分析了不同的物性条件下,常温输送原油对加热输送原油的热力影响.     

对-叔丁基杯[8]芳烃键合硅胶制备及其毛细管电色谱性能研究

以γ-(环氧丙氧)丙基键合硅胶为前体,于硅胶表面键合环氧基,在催化剂存在下以杯芳烃钠盐开环制备杯芳烃键合硅胶固定相.该方法反应条件温和,适用性强.将这个新方法首次用于制备对-叔丁基杯[8]芳烃电色谱键合固定相(C8BS),采用加压电色谱初步评价其电色谱性能.研究结果表明,C8BS电渗流(Electrosmoticflow,EOF)较小,但通过控制键合反应及使用压力辅助电色谱可部分弥补上述不足.该固定相的EOF受流动相pH影响小(pH=3-8),同时大环配体屏蔽效应能有效地克服硅羟基引起的碱性化合物拖尾现象,这对电色谱分离具有重要意义.通过分步封尾研究EOF的来源发现,杯芳烃酚羟基对EOF有弱的贡献,这与报道的杯芳烃涂层具有径向电渗流调控能力相一致.     

蒙药新-Ⅱ中微量硒的测定

采用硒 -硫氰酸钾 -罗丹明 B-明胶 - OP体系分光光度法测定蒙药新 - 中微量硒。其含量为 6 .6—7.3μg· g-1 ,回收率为 94 %— 95 %。     

天然磷脂的色谱法分离、纯化研究进展

天然磷脂是一类含磷酸根的类脂化合物的总称,在医药学、营养学、化妆品和生命科学领域等有重要的应用价值。本文综述了不同原料样品中磷脂种类和其各分子的色谱法分离、纯化。着重讨论高效液相色谱法分离技术及其影响因素。最后概述了有助于提高分离选择性、检测灵敏度的化学衍生化方法。     

Screening for galectin-3 inhibitors from synthetic lacto-N-biose libraries using microscale affinity chromatography coupled to mass spectrometry

The synthesis and screening of two beta-D-Galp-(1-3)-beta-d-GlcpN (lacto-N-biose) disaccharide libraries are reported. Solution-phase synthetic modifications at the HO-2' and NH positions were performed in an effort to enhance the affinity toward galectin-3, a galactose-binding protein involved in tumor metastasis, apoptosis, and inflammation. The libraries were screened for galectin-3 binding by microscale frontal affinity chromatography coupled to mass spectrometry (FAC/MS) allowing for rapid ranking of the different inhibitors and the determination of the galectin-3 binding Kd's. Compounds bearing a hydrophobic substituent on the NH group showed the highest affinity for the lectin. The N-naphthoyl derivative (Kd = 10.6 microM) was the best inhibitor with a 7 times increased affinity as compared to the N-acetyl parent compound (Kd = 73.3 microM).     

基于集合卡尔曼变换的东中国海声学 敏感区判定方法*

为改善海洋与水声环境预报质量,针对常规观测成本高、资料利用率低等问题,将适应性观测方法应用于海洋声学领域。结合海洋-声学耦合模式与集合卡尔曼转换敏感区诊断方法,以东中国海宫古海峡北部区域为验证区,计算并分析不同条件下海洋环境敏感区与声学敏感区分布,通过观测系统模拟试验验证适应性观测对验证区预报的提升效果。结果表明,两种敏感区位置随时间间隔增加均向验证区上游移动,海洋环境敏感区相比于声学敏感区分布更为集中,且平移特征更明显;对海洋环境敏感区和声学敏感区添加适应性观测均能提升海洋与水声环境的预报质量,提升效果随时间间隔增加而减小,在某种类型敏感区的适应性观测对相对应参数的预报质量提升效果优于对其他类型敏感区进行观测的效果。