Simultaneous determination of microcystin-LR and its glutathione conjugate in fish tissues by liquid chromatography-tandem mass spectrometry

A sensitive and selective liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantitative determination of microcystin-LR (MC-LR) and its glutathione conjugate (MC-LR-GSH) in fish tissues. The analytes were extracted from fish liver and kidney using 0.01 M EDTA-Na-2-5% acetic acid, followed by a solid-phase extraction (SPE) on Oasis HLB and silica cartridges. High-performance liquid chromatography (HPLC) with electrospray ionization mass spectrometry, operating in selected reaction monitoring (SRM) mode, was used to quantify MC-LR and its glutathione conjugate in fish liver and kidney. Recoveries of analytes were assessed at three concentrations (0.2, 1.0, and 5 mu g g(-1) dry weight [DW]) and ranged from 91 to 103% for MC-LR, and from 65.0 to 75.7% for MC-LR-GSH. The assay was linear within the range from 0.02 to 5.0 mu g g(-1) DW, with a limit of quantification (LOQ) of 0.02 mu g g(-1) DW. The limit of detection (LOD) of the method was 0.007 mu g g(-1) DW in both fish liver and kidney. The overall precision was determined on three different days. The values for within- and between-day precision in liver and kidney were within 15%. This method was applied to the identification and quantification of MC-LR and its glutathione conjugate in liver and kidney of fish with acute exposure of MC-LR. (c) 2007 Elsevier B.V. All rights reserved.

Determination of phthalate acid esters plasticizers in plastic by ultrasonic solvent extraction combined with solid-phase microextraction using calix[4]arene fiber

Ultrasonic solvent extraction combined with solid-phase microextraction (SPME) with calix[4]arene/hydroxy-terminated silicone (C[4]/OHTSO) oil coated fiber was used to extract phthalate acid esters (PAEs) plasticizers in plastic, such as blood bags, transfusion tubing, food packaging bag, and mineral water bottle for analysis by gas chromatography (GC). Both extraction parameters (i.e. extraction time, extraction temperature, ionic strength) and conditions of the thermal desorption in a GC injector were optimized by analysis of eight phthalates. The fiber shows wonderful sensitivity and selectivity to the tested compounds. Owing to its high thermal stability (380 degreesC), the carryover effect that often encountered when using conventional fibers can be reduced by appropriately enhancing the injector temperature. The method showed linear response over two to four orders of magnitude with correlation coefficients (r) better than 0.996, and limits of detection (LOD) ranged between 0.006 and 0.084 mug l(-1). The relative standard deviation values obtained were less than or equal to 10%. bis-2-Ethylhexyl phthalate (DEHP) was the sole analyte detected in these plastics and recoveries were in the ranges 95.5-101.4% in all the samples. (C) 2004 Elsevier B.V. All rights reserved.

基于几何的网格模型编辑处理的研究

在计算机动画、 计算机辅助设计、 计算机视觉等领域，几何模型通常用三角网格来表示。 为了能够快速真实地 绘制几何体，规则且细节丰富的几何模型有利于使用GPU进行加速。本文基于网格模型，在模型的重采样、变体，以及图像变形方面进行了针对性的研究。 论文的贡献主要体现在以下几个方面: 第一， 将现有的差分坐标的概念扩展到图像上，首次提出差分几何图像的概念， 将几何模型的差分坐标信息封装在与几何图像(geometry images或GIM)类似的结构中。由于差分坐标反映了几何模型的局部特性，于是差分几何图像也就将局部信息封装到了图像中。 第二，我们展示了使用差分几何图像作为限定条件来适应不同的应用。对于网格重建来说，传统使用GIM重建的方法需要记录采样顶点的法向信息以用于绘制模型， 因为使用对角线连接的固定连接方式导致了局部信息的丢失，使得采样后按顶点位置计算的真实法向和曲率与记录的法向信息不能精确一致。即使记录了法向信息，模型在一些广泛应用的软件如3D Exploration等里面仍然不能正确显示， 因为这些软件是按顶点的位置来自动计算法向而不是根据模型文件记录的法向对模型进行绘制的。使用我们的方法， 模型的局部形状可以正确地保持，从而模型可以正确地显示， 无需再记录法向信息。 对于变体来说，由于局部形状（包括法向和曲率）被正确地保持，并且使用我们的重建算法， 所有的模型有相同的拓扑结构，于是可以利用差分几何图像生成的模型得到正确的变体模型。另外，由于参数化方式的统一性，我们可以在GPU上动态绘制层次细节(Level Of Detail或LOD)几何模型。 第三， 改进了现有的使用形状空间进行变形的算法 。 在形状空间中，由三角形网格构成的模型可视为空间中的一个点，可以借助黎曼度量对形状空间进行操作， 从而实现对模型的变换。本文改进了已有的操纵形状空间的方法，根据输入模型顶点的位置变化判断是否需要利用黎曼度量计算插值位置，从而降低了形状空间的维数， 提高了运算速度。 实验结果显示，混合线性插值方式而生成的模型具有良好的效果。 第四， 对使用笼体进行图像变形的方法进行了对比分析， 并作了改进，在GPU上加速以达到快速实时变形。本文将现有的使用笼体进行变形的坐标诸如均值坐标、调和坐标、格林坐标等统一成类似的形式，对2D图像进行变形。笼体通过针对ROI(Region of Interest)区域进行交互式生成。我们设计了一种简单的方法保证图像在变形过程中整体上基本保持不变。与此同时，构建了使用GPU加速笼体坐标变形图像的框架。 结果显示，这种直观的交互方式和实时的绘制速度便于应用到2D图像的动画设计中，其动画通过设定笼体顶点的运动速度来实现。

基于libMini的动态地形实时渲染算法

为了减少地形动态变化时的地形计算时间,满足动态地形实时可视化的需要,在地形渲染库libMini的基础上,依据地形动态变化的局部性特点,以及库中LOD(Level ofDetail)算法的具体实现方式,运用局部更新的思想,提出了一种动态地形实时计算和渲染算法.算法避免了在地形动态变化时进行大量重复计算,使得在地形动态变化时所需的计算量大大减少,达到实时渲染要求.实验表明,算法使得局部地形动态变化时地形计算和渲染的时间从秒级降低到毫秒级,可以满足实时渲染要求.

基于GPU的球面深度图实时绘制

提出了一种GPU加速的实时基于图像的绘制算法.该算法利用极坐标系生成对物体全方位均匀采样的球面深度图像;然后根据推导的两个预变换公式将单幅球面深度图像预变换到物体包围球的一个与视点相关的切平面上,以生成中间图像;再利用纹理映射生成最终目标图像.利用现代图形硬件的可编程性和并行性,将预变换移植到Vertex Shader来加快绘制速度;利用硬件的光栅化功能来完成图像的插值,以得到连续无洞的结果图像.此外,还在Pixel Shader上进行逐像素的光照以及环境映射的计算,生成高质量的光照效果.最终,文章解决了算法的视点受限问题,并设计了一种动态LOD(Level of Details)算法,实现了一个实时漫游系统,保持了物体间正确的遮挡关系.

Fluorescent conjugated polymer-stabilized gold nanoparticles for sensitive and selective detection of cysteine

We report a new fluorescent detection method for cysteine based on one-step prepared fluorescent conjugated polymer-stabilized gold nanoparticles. The as-prepared fluorescent conjugated polymer-stabilized gold nanoparticles fluoresce weakly due to the fluorescence resonance energy transfer between the fluorophore and the gold nanoparticles. Upon the addition of cysteine, a thiol-containing amino acid, the fluorescence of the colloidal solution increases significantly, indicating that cysteine can modulate the energy transfer between fluorophore and gold. This phenomenon then allows for sensitive detection of cysteine with a limit of detection (LOD) of 25 nM. The linear range of determination of cysteine is from 5 x 10(-8) to 4 x 10(-6) M. None of the other amino acids found in proteins interferes with the determination. Moreover, due to the excellent protecting ability of the fluorescent conjugated polymers, the synthesis of metal nanoparticles and modifying with fluorophores can be accomplished within one step, which makes our method much simpler than conventional methods. We also expect that it will be possible to detect other biologically important analytes based on the fluorescent conjugated polymer-stabilized metal nanoparticles.

Electrochemiluminescence detection with integrated indium tin oxide electrode on electrophoretic microchip for direct bioanalysis of lincomycin in the urine

In this article, an antibiotic, lincomycin was determined in the urine sample by microchip capillary electrophoresis (CE) with integrated indium tin oxide (ITO) working electrode based on electrochemiluminescence (ECL) detection. This microchip CE-ECL system can be used for the rapid analysis of lincomycin within 40 s. Under the optimized conditions, the linear range was obtained from 5 to 100 muM with correlation coefficient of 0.998. The limit of detection (LOD) of 3.1 muM was obtained for lincomycin in the standard solution. We also applied this method to analyzing lincomycin in the urine matrix. The limit of detection of 9.0 muM was obtained. This method can determine lincomycin in the urine sample without pretreatment, which demonstrated that it is a promising method of detection of lincomycin in clinical and pharmaceutical area.

Determination of reserpine in urine by capillary electrophoresis with electrochemiluminescence detection

A fast and sensitive approach to detect reserpine in urine using micellar electrokinetic capillary chromatography with electrochemiluminescence (ECL) of Ru(bpy)(3)(2+) detection is described. Using a 25 mum i.d. capillary as separation column, the ECL detector was coupled to the capillary in the absence of an electric field decoupler. Field-amplified injection was used to minimize the effect of ionic strength in the sample and to achieve high sensitivity. In this way, the sample was analyzed directly without any pretreatment. The method was validated for reserpine in the urine over the range of 1 x 10(-6) - 1 x 10(-4) mol/L with a correlation coefficient of 0.996. The RSD for reserpine at a level of 5 mumol/L was 4.3%. The LOD (S/N = 3) was estimated to be 7.0 x 10(-8) mol/L. The average recoveries for 10 mumol/L reserpine spiked in human urine were 94%.

Simultaneous determination of tramadol and lidocaine in urine by end-column capillary electrophoresis with electrochemiluminescence detection

Tramadol and lidocaine, used as analgesic and local anesthetic in surgery, are partly excreted by kidney. For the first time, we developed a simple and sensitive method, based on capillary electrophoresis with electrochemiluminescence (ECL) detection by end column mode without joint to monitor tramadol and lidocaine in urine. To eliminate the influence of ionic strength of urine sample, analytes were extracted by ether. Tripropylamine (TPA) was used as internal standard. ne recoveries of tramadol and lidocaine were between 94% and 97% at different levels. The method exhibited the linear range for the tramadol and lidocaine from 1.0 X 10(-7) to 1.0 X 10(-4) mol/L with correlation efficient of 0.998. The relative standard deviation (RSD) was 2.9% and 2.7% (n = 8) for tramadol and lidocaine, respectively. The limit of detection (LOD) was 6.0 x 10(-8) mol/L and 4.5 x 10(-8), mol/L (S/N = 3) for tramadol and lidocaine, respectively. The application for detecting tramadol and lidocaine in urine of patients showed that the method was valuable in clinical and biochemical laboratories for detecting tramadol, lidocaine and other tertiary amine pharmaceuticals for various purpose, such as metabolism investigation.

Determination of propranolol by capillary electrophoresis with end-column amperometric detection

A capillary electrophoresis-amperometric detection system was developed for the determination of propranolol (PRO) at a 33 mu m carbon fiber microdisk electrode (CFE). The cyclic voltammogram, the hydrodynamic voltammograms and the effect of pH were studied. Under the optimum conditions: separation Voltage 15 kV; injection 3 s at 15 kV; 10 mM pH 7.5 phosphate buffer, 1.15 V (vs. Ag/AgCl) detection potential, the detection limit (LOD) for PRO was 0.05 mu M (S/N = 3). The response for PRO was linear over two orders of magnitude with a linear correlation coefficient of 0.994. The feasibility of this method was demonstrated by the detection of PRO in urine sample.

Construction of AFLP-based genetic linkage map for Zhikong scallop, Chlamys farreri Jones et Preston and mapping of sex-linked markers

Zhikong scallop (Chlamys farreri) is an economically important aquaculture species in China; however, frequent mass mortality seriously affects the development of its industry. Genetic linkage map is useful for genetic improvement and selective breeding of C. farreri. Linkage maps were constructed using an intraspecific F-1 cross and amplified fragment length polymorphism (AFLP) markers. Thirty-two selected AFLP primer combinations produced 545 AFLP markers that were polymorphic in either of the parents and segregated in the progeny. Of these segregating markers, 166 were mapped to 19 linkage groups of the female framework map, covering a total of 1503.9 cM, with an average marker spacing of 10.2 cM; and 197 markers were assigned to 20 linkage groups of the male map, covering a total of 1630.7 cM, with 9.2 cM per marker. A sex-linked marker was mapped on the female map with zero recombination and a LOD of 27.3. The genetic length of C farreri genome was estimated as 1889.0 cM for the female and 1995.9 cM for the male. The coverage of the framework map was calculated as 79.6% for the female and 81.7% for the male. When the triplets and doublets were considered, the observed length of the map was calculated as 1610.2 cM with coverage of 85.2% for the female, and 1880.5 cM with coverage of 94.2% for the male. The genetic maps presented here will serve as a basis for the construction of a high-resolution genetic map and mapping of economically important genes. (C) 2004 Published by Elsevier B.V.

A genetic linkage map of Pacific white shrimp (Litopenaeus vannamei): sex-linked microsatellite markers and high recombination rates

Pacific white shrimp (Litopenaeus vannamei) is the leading species farmed in the Western Hemisphere and an economically important aquaculture species in China. In this project, a genetic linkage map was constructed using amplified fragment length polymorphism (AFLP) and microsatellite markers. One hundred and eight select AFLP primer combinations and 30 polymorphic microsatellite markers produced 2071 markers that were polymorphic in either of the parents and segregated in the progeny. Of these segregating markers, 319 were mapped to 45 linkage groups of the female framework map, covering a total of 4134.4 cM; and 267 markers were assigned to 45 linkage groups of the male map, covering a total of 3220.9 cM. High recombination rates were found in both parental maps. A sex-linked microsatellite marker was mapped on the female map with 6.6 cM to sex and a LOD of 17.8, two other microsatellite markers were also linked with both 8.6 cM to sex and LOD score of 14.3 and 16.4. The genetic maps presented here will serve as a basis for the construction of a high-resolution genetic map, quantitative trait loci (QTLs) detection, marker-assisted selection (MAS) and comparative genome mapping.

海湾扇贝微卫星标记的开发及遗传连锁图谱的构建

海湾扇贝（Argopecten irradians）不连续分布于美国大西洋沿岸和墨西哥湾沿岸，自1982年以来北部亚种（A. i. irradians）和南部亚种（A. i. concentricus）被先后引进到中国，由于其生长速度快、繁殖周期短和适宜温度范围广的特点，迅速成为我国海水养殖的重要品种。近年来飞速发展的分子标记技术为优良品种的选育注入了新的活力，相对于传统的表型选择来说，标记辅助选择不易受环境的影响，尤其是对于低遗传力性状和后期表达的性状，能增强选择效率，提高选择的准确度，缩短育种周期。本文通过构建海湾扇贝微卫星富集文库获得大量的微卫星DNA序列，筛选多态的微卫星标记构建了海湾扇贝的遗传连锁图谱，并应用复合区间作图法对生长相关性状进行了QTL定位。 本研究利用富集文库-菌落原位杂交法筛选海湾扇贝微卫星DNA，吸附(AC)15和(AG)15探针的尼龙膜捕捉并富集含有微卫星序列的片段，菌落原位杂交结果显示阳性克隆率达到40%，测序比对后获得521个独立的阳性克隆，其中微卫星506个，小卫星15个。微卫星中，完美型248个，占49.0%，非完美型216个，占42.7%；复合型42个，占8.3%；AG/TC重复占大多数（356个，70.4%），AC/TG重复有150个（29.6%）。设计合成了382对引物，利用38个海湾扇贝个体对其中15个微卫星位点进行了遗传多样性评价，不同位点扩增得到的等位基因数从3到7个不等，期望杂合度和观测杂合度的范围分别为0.198~0.813和0.083~0.833，实验结果表明富集文库-菌落原位杂交法适合大规模筛选微卫星标记。 利用8个微卫星标记对海湾扇贝1个野生种群和3个养殖群体的遗传多样性与分化进行了比较和分析。8个位点共扩增得到35个等位基因，平均每个位点4.38个等位基因，平均有效等位基因数为2.30，平均观测杂合度和期望杂合度分别为0.41和0.46。相比于野生群体（美国），养殖群体（北卡罗来那、浙江和胶南）的等位基因数和杂合度都有所降低，在封闭环境下养殖19代的浙江群体等位基因数丢失最严重，共有9个等位基因丢失（25.7%）。经过多代人工养殖后，海湾扇贝养殖与野生群体之间和养殖群体之间出现了明显的遗传分化，胶南群体与野生群体的遗传距离最大，而胶南群体与浙江群体的遗传距离已经超过了胶南群体（北部亚种）和北卡罗来那（南部亚种）群体的遗传距离，这种分化将有利于海湾扇贝的杂交选育。 利用167个微卫星标记和1个壳色标记，以海湾扇贝2个全同胞F1代为作图群体，构建了海湾扇贝的性别遗传连锁图谱。整合的雌性连锁图谱含有118个标记，覆盖了16个连锁群，每个连锁群含有的标记数目从4到16个不等，平均每个连锁群上有7.4个标记，图谱总长度为761.0 cM，标记间的平均间隔为8.55 cM，图谱的覆盖率为73.5%；整合雄性连锁图谱含有126个标记，覆盖了17个连锁群，每个连锁群含有的标记数目从2到11个不等，平均每个连锁群上有7.4个标记，图谱总长度为729.1 cM，标记间的平均间隔为6.75 cM，图谱的覆盖率为74.7%。雌性亲本的重组率高于雄性，雌雄亲本共享标记间的重组率比值为1.18：1。偏分离标记在性别间呈现不对称分布，雄性亲本的偏分离高于雌性亲本，可能与雄性亲本来源于亚种间杂交的遗传背景相关。 利用海湾扇贝微卫星遗传连锁图谱在两个作图家系中对5个生长性状的QTL进行了定位，5个生长性状的表型相关均达到极显著水平（P < 0.01），Pearson相关系数均超过0.781，总重、壳长、壳宽、壳高和壳重的QTL（LOD > 2.0）的数目分别为8、6、6、7和6个。这些QTL成簇分布于CC5家系的LG1、LG3、LG4、LG8和CC10家系的LG1、LG3、LG6、LG8、LG9连锁群，单个QTL可解释的表型方差为5.5%到29.2%，QTL成簇分布现象说明这些生长相关的性状可能具有共同的遗传基础，家系特异性QTL暗示在不同的遗传背景和环境下存在不同的主效QTL。本研究定位的QTL，尤其在两个家系中共享的QTL为下一步分子标记辅助选择提供了参考区间。