Electrochemiluminescence of tris(2,2 '-bipyridine)ruthenium(II) immobilized in poly(p-styrenesulfonate)-silica-Triton X-100 composite thin-films

The electrochemiluminescence (ECL) of tris(2,2'-bipyridine)ruthenium(ii) [Ru(bpy)(3)(2+)] immobilized in poly(p-styrenesulfonate) (PSS)-silica-Triton X-100 composite films was investigated. The cooperative action of PSS, sol-gel and Triton X-100 attached Ru(bpy)(3)(2+) to the electrode strongly, and the presence of Triton X-100 prevented drying fractures of the sol-gel films during gelation and even on repeated wet-dry cycles. The modified electrode was used for the ECL detection of oxalate, tripropylamine (TPA) and NADH in a flow injection analysis (FIA) system with a newly designed flow cell. The detection scheme exhibited good stability, short response time and high sensitivity. Detection limits were 0.1, 0.1 and 0.5 mu mol L-1 for oxalate, TPA and NADH, respectively, and the linear concentration range extended from 0.001 to 1 mmol L-1 for the three analytes. Applications of the flow cell in ECL and electrochemical detection, as well as the immobilization of reagents based on the cooperative action, are suggested.

Review on study of resonance electron capture mass spectrometry

Resonance electron capture mass spectrometry, in which an additional information coordinate, the energy of electron capture, is applied, has a high sensitivity and a high specificity. It is extensively used to study the structure elucidation, the mechanism of ion formation and the detection, identification and quantification of organic substances in mixture.

Combination of amperometric detector & UV detector for capillary electrophoresis

A new electrochemical cell assembly with the combination of UV and amperometric detector (AD) based on their complementarity was described. A Nafion tubing junction was used to decouple the high voltage from the separation capillary in the rear of on-column UV detector. In this mode, the electroactive and inert compounds could be detected by UV and AD at the same time. Aromatic amines were determined with the UV and the end-column AD detection to evaluate the performances of the cell assembly. Such an improved electrochemical detector could match the capillary with different diameters. By simple adjustment of the screws, the positioning of the working electrode and the detection capillary was easily gained without microscope. It is also very easy to assemble and disassemble the working electrode when needed. (C) 1999 Elsevier Science B.V. All rights reserved.

Self-gelatinizable copolymer immobilized glucose biosensor based on Prussian Blue modified graphite electrode

A novel poly(vinyl alcohol) grafting 4-vinylpyridine self-gelatinizable copolymer was adapted to immobilize glucose oxidase. The reduction of hydrogen peroxide (H2O2) was detected at a Prussian Blue (PB) modified graphite electrode. A stable and sensitive glucose amperometric biosensor is described. The copolymer is a good biocompatible polymer in which the glucose oxidase retains high activity. Moreover, the copolymer can adhere firmly to the inorganic PB membrane. The sensor showed an apparent Michaelis-Menten constant of 18 +/- 0.2 mM and a maximum current density of 1.14 mu A cm(-2) mM(-1). The linear range is from 5 mu M to 4.5 mM glucose and the detection limit is 0.5. mu M glucose. The catalytic efficiency of PB for the reduction of H2O2 is higher than that for the oxidation of H2O2. Glucose concentrations in serum samples from healthy persons and diabetic patients were determined using the sensor. The results compared well with those provided by the hospital using a spectroscopy method.

Donut-shaped spray chamber for inductively coupled plasma spectrometry

A donut-shaped spray chamber has been developed for the introduction of aerosol and/or volatile chemical species into the inductively coupled plasma. Compared with the Fassel-Scott spray chamber, it gives a higher efficiency of aerosol generation and transportation and superior stable inner pressure. As a result, it brings the benefits of higher intensity signal, lower background, higher measurement precision, and better detection limits. Using:his spray chamber, it is more convenient to introduce volatile chemical species into the sampling system, and more flexible for the choice of introducing aerosol and volatile chemical species separately or simultaneously into the plasma. It is also suitable for FIA technique. (C) 1998 Elsevier Science B.V. All rights reserved.

ENHANCED AMPEROMETRIC DETECTOR FOR LOCAL-ANESTHETICS IN LIQUID-CHROMATOGRAPHY WITH METAL-OXIDE DISPERSED GLASSY-CARBON ELECTRODES

Chemically modified electrodes (CMEs) prepared by the dispersion of metal oxide particles on a glassy carbon (GC) substrate greatly enhance the voltammetric response and amperometric detection of local anesthetics following liquid chromatography (LC). The enhancement is more pronounced with the GC electrodes dispersed by the metal oxides of higher oxidation states (+3, +4) and for the species exhibiting relatively slow electrode kinetics under given conditions. With an applied potential of 1.2 V (vs. SCE), LC amperometric detection of the analytes at the alpha-alumina modified GC surface gives detection limits 2-5 times lower than those obtained at the bare electrode. The metal oxide-dispersed electrodes display significant improvement in sensitivity, and selectivity and indicate excellent preparation reproducibility and performance stability.

AN ELECTROCHEMICAL MICROSENSOR FOR CHLORIDE

The potential-response of a microdisk electrode made with a chloride-doped polypyrrole (PPY) film on a carbon fibre (CF) has been examined. The effect of the polymerization conditions on the response characteristics is discussed. The optimum conditions for preparing the electrode are: cycling potential from +0.8 to +1.0 V in 0.1-0.2M pyrrole (Py) containing 0.1M LiCl, electropolymerization time 15-20 min. The electrode gives a Nernstian response of 56-58 mV/pCl and a detection limit of 3.6 x 10(-5)M chloride. It has the advantages of low resistance, short conditioning time and fast response. It has been used satisfactorily for detection of chloride in serum.

Using the ribosomal internal transcribed spacer (ITS) as a complement marker for species identification of red macroalgae

Barcodes based on mitochondrial cytochrome oxidase (mtDNA CO1) sequences are being used for broad taxonomic groups of animals with demonstrated success in species identification and cryptic species discovery, but it has become clear that complementation by a nuclear marker system is necessary, in particular for the barcoding of plants. Here, we propose the nuclear internal transcribed spacer (ITS) as a potentially usable and complementary marker for species identification of red macroalgae, as well as present a primary workflow for species barcoding. Data show that for most red macroalgal genera (except members of the family Delesseriaceae), the size of ITS region ranges from 600 to 1200 bp, and contains enough variation to generate unique identifiers at either the species or genus levels. Consistent with previous studies, we found that the ITS sequence can resolve closely related species with the same fidelity as mtDNA CO1. Significantly, we confirmed that length polymorphism in the ITS region (including 5.8S rRNA gene) can be utilized as a character to discriminate red macroalgal species. As a complementary marker, the verifiable nuclear ITS region can speed routine identification and the detection of species, advance ecological and taxonomic inquiry, and permit rapid and accurate analysis of red macroalgae.

结核分枝杆菌基因组学及特异检测技术研究

结核分枝杆菌(M.tuberculosis)，俗称结核杆菌，是引起结核病的病原菌。可侵犯全身各器官，但以肺结核为最多见。结核病至今仍为重要的传染病。估计世界人口中1/3感染结核分枝杆菌。据WHO报道，每年约有800万新病例发生，至少有300万人死于该病。我国建国前死亡率达200-300人/10万，居各种疾病死亡原因之首，建国后，随着人民生活水平提高，卫生状态改善，特别是开展了群防群治，儿童普遍接种卡介苗，结核病的发病率和死亡率大为降低。由于耐药结核的出现已及HIV共感染等因素影响，目前发病率又有上升趋势。对于结核病的防治而言，其首要问题是结核病的诊断，而结核病的实验室检查已成为临床医生诊断结核病、判断疗效和评估预后不可缺少的手段。结核病的临床诊断主要根据病史、痰培养、涂片抗酸染色、胸片等结果，其中痰结核检查是诊断肺结核的重要依据之一，检测方法常规采用细菌学检查。痰中细菌学检查主要采用痰涂片和培养方法，涂片虽简单易行，但阳性率低，培养虽为金标准，但周期太长，均难以满足临床需要。细菌对部分患者可造成误诊或漏诊。近年来随着现代科学技术的不断进展，分子生物学技术在结核病诊断方面取得了显著的成绩，实时动态荧光定量(FQ—PCR)技术又是在原有的PCR技术上一次质的飞跃。 尽管许多文献已经报道了结核耐药的分子机理，但耐药的分子机理并没有充分了解。本研究利用全基因组鸟枪法测序和高通量测序技术，测定了两株结核分枝杆菌菌株TFJA和TFJB全基因组序列，分别为药物敏感株和耐多药株。在序列初步拼接后，获得了由189个DNA contigs（DNA序列连接群）组成的基因组框架图。借助10kb左右插入片段克隆的正反向末端序列信息以及PCR扩增技术，确定了全部DNA contigs在基因组上的物理位置，最后补上了所有“间隙(gap)” ，得到了全基因组序列。三种限制性酶切物理图谱证明了序列拼接的正确性。两株结核菌基因组大小为4.4Mbp左右，GC含量都在65.6%左右，其中TFJB株比TFJA株大7kbp，分别具有3591、3648个基因，83.7%的基因位于先导链上。我们比较了两株细菌的949SNPs位点，发现94个在TFJB中不同nsSNPs，这些SNPs位点的碱基在其它的结核分枝杆菌基因组中是相同的。我们去掉了那些代谢途径与毒力代谢无关的基因，最后选择了6个基因的18个SNP，检测这些SNP在277株耐药或者药物敏感结核分枝杆菌中的保守性以及其耐药相关性。用PCR扩增含有SNP的序列，用统计学检验这些SNP是否耐药相关，结果发现，TFJB0109_CDS04405基因的407位点SNP（g->a）和TFJB0109_CDS00149基因上的SNP（720a->c，722插入t，727t->g，729g->t，以及735g->t）可能与SM耐药相关，其P-value分别是0.04128、0.02160和0.01394（见表3）。 结核是一种慢性传染病，其病原体为TB。在全基因组序列分析研究的同时，我们筛选到一套灵敏度较高、特异性较好的REAL TIME-PCR检测引物，并用它对105份不同发病时间的病人标本进行了检测。初步结果表明，应用本方法，样本检出率为98%，这一结果比涂片及分离培养更灵敏。

Simultaneous Determination of Multi-Organotin Compounds in Seawater by Liquid-Liquid Extraction-High Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

The hyphenated technique of high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was applied to the simultaneous determination of five organotin compounds (trimethyltin, dibutyltin, tributyltin, diphenyltin and triphenyltin) in seawater samples. Agilent TC-C18 column was used for the separation, the mobile phase of HPLC was CH3CN : H2O: CH3COOH=65 : 23 : 12 (phi), 0.05% TEA, and pH value was adjusted to 3.0 by diluent ammonia. The flow rate was 0.6 mL . min(-1). Five mixed organotin compounds in a mix standard solution from 100 to 0.5 mu g . L-1 were applied for the method assessment. The experimental results indicate that the correlation coefficient of calibration curves (R-2) for each organotin compound was over 0.998 and the detection limits of the five organotin compounds were lower than 3 ng . L-1. Different mixed organic solvents including dichloromethane or toluene were used for extraction of organotin and the extraction condition of organotin from seawater was optimized. The 100 mL seawater acidized by hydrochloric acid was extracted by 10 mL carbon dichloride (CH2Cl2) with 2% tropolone for 10 min twice. Extracted organic solvents were mixed And blown to one drop by nitrogen with the rate of 1.7 mL . min(-1), then 1 mL acetonitrile was added to the drop for redissolving the organotin compounds. Finally, the mixed redissolution was filtered by 0.22 mu m organic filter membrane before analysis. it was found that the only organotin compound in seawater was triphenyltin (TPHT) and the content was 53.2 ng . L-1. The recoveries test from the standard addition for diphenyltin (DPHT), dibutyltin (DBT), tributyltin (TBT) and triphenyltin (TPHT) were over 80%. However, the recovery for trimethyltin (TMT) was relatively low and the value was 50%. The reason might be attributed to the decomposition or adsorption of those compounds during the extraction procedure. Further study on this subject is in progress.

基于无线通信的阀门泄漏检测系统

阀门泄漏的在线监测一直是困扰流程工业的难题,采用传统有线监控方式需要巨大的布线安装成本。本文通过结合无线通信技术和超声检测技术,研究并开发了一种基于无线通信的阀门泄漏检测系统,可极大地降低测控系统的投资和使用成本,通过实时检测阀门的工作状态,及时发现并定位泄漏位置,实现工业生产的节能降耗。

基于几何特征的快速高精度角点检测算法

角点检测应用十分广泛,是许多计算机视觉任务的基础。本文提出了一种快速、高精度的角点检测算法,算法简单新颖,角点条件和角点响应函数设计独特。和以往不同的是:算法在设计上考虑的是角点的局部几何特征,使得处理的数据量大为减少,同时能够很好地保证检测精度等其他性能指标。通过和广泛使用的SUSAN算法、Harris算法在正确率、漏检、精度、抗噪声、计算复杂度等方面进行综合比较,结果表明该算法无论对人工合成图像还是对自然图像均具有良好的性能。

人脸检测的一种混合方法研究

人脸检测作为自动人脸识别系统的第一个环节具有非常重要的作用,为了解决目前大部分人脸检测方法存在的分类器训练困难和检测计算量大等问题,提出了一种人脸检测的混合方法。该方法由两级分类器组成,第一级为粗分类器主要过滤大部分非人脸区域,第二级为核心分类器,在由第一级粗分类的基础上利用非线性SVM算法进行人脸检测。在CMU数据库上的实验结果表明,该方法具有较高的人脸检测率,检测速度得到大幅提高。

数字式热轴自动判别及集中检测系统

本文阐明了数字式热轴自动判别及集中检测的原理,并从理论上对一些重点环节进行分析。该系统经过实践检验,证明性能良好,功能齐全,自动判别准确率高。

基于弹性参数分析的碳酸盐岩储层预测方法研究

Prediction of Carbonate Reservoir Based on the Elastic Parameter Analysis Zhang Guangzhi (Solid Geophysics) Directed by Professor Liu Hong Abstract With the exploration and development of Puguang Oilfield, oil-gas exploration of carbonate rock in China has shown good prospects. Research on earthquake prediction methods for carbonate reservoir becomes the key of oil and gas exploration. Starting with analysis of geological characteristics of carbonate rock, prestack AVO inversion method, prestack elastic impedance inversion and parameter calculation method and seismic attribute extraction and optimization method were studied based on the analysis of rock physics in this work. First, variation characteristic and law of carbonate rock reservoir parameters were studied based on experimental data of rock physics, log data, analysis assay data, mud logging data and seismic data, so as to lay a foundation for the further reservoir identification and description. Then, the structure, type and propagation law of seismic wave field were analyzed through seismic forward modeling of the reservoir, and contact between information from log and geology data with elastic parameters, such as compressional wave and shear wave velocity and density were established, so as to provide a standard for reservoir identification and hydrocarbon detection using seismic reflection characteristics of the research area. Starting with the general concept of inverse problem, through analysis of Zoeppritz equation, three kinds of pre-stack inversion methods were derived and analyzed in detail, the AVO 3-parameter inversion based on Bayesian theory, the prestack AVO waveform inversion method and the simultaneous inversion method, based on the statistical hypothesis of inversion parameters and observation data and the Gauss distribution assumption of noise. The three methods were validated by model data and real data. Then, the elastic wave impedance inversion method of carbonate reservoir was investigated and the method of elastic parameter extraction from elastic impedance data was put forward. Based on the analysis of conventional methods of seismic attribute extraction and optimization, the time-frequency attributes and the wavelet attributes with time and amplitude feature were presented, and the prestack seismic attribute calculation method which can characterize the reservoir rock and fluid characteristic was presented. And the optimization of seismic attribute using the nonlinear KPCA method was also put forward. A series of seismic prediction technologies for carbonate reservoir were presented based on analysis of rock physics and seismic forward simulation technology. Practical application of these technologies was implemented in A oil field of Southern China and good effect has been achieved. Key words: carbonate rock; reservoir prediction; rock physics, prestack seismic inversion; seismic attribute