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Use of microfluidics chips for the detection of human telomerase RNA

ANALYTICAL BIOCHEMISTRY 2003年第2期313卷 331-334页

作者： Fuller, RA Clark, J Kretzner, L Korns, D Blair, SL Crocitto, LE Smith, SS City Hope Natl Med Ctr Duarte CA 91010 USA

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Automatic classification of sub-microlitre protein-crystallization trials in 1536-well plates

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ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY 2003年第9期59卷 1619-1627页

作者： Cumbaa, CA Lauricella, A Fehrman, N Veatch, C Collins, R Luft, J DeTitta, G Jurisica, I Ontario Canc Inst Toronto ON M5G 2M9 Canada Hauptman Woodward Med Res Inst Buffalo NY 14203 USA

A technique for automatically evaluating microbatch (400 nl) protein-crystallization trials is described. This method addresses analysis problems introduced at the sub-microlitre scale, including non-uniform lighting and irregular droplet boundaries. The droplet is segmented from the well using a loopy probabilistic graphical model with a two-layered grid topology. A vector of 23 features is extracted from the droplet image using the Radon transform for straight-edge features and a bank of correlation filters for microcrystalline features. Image classification is achieved by linear discriminant analysis of its feature vector. The results of the automatic method are compared with those of a human expert on 32 1536-well plates. Using the human-labeled images as ground truth, this method classifies images with 85% accuracy and a ROC score of 0.84. This result compares well with the experimental repeatability rate, assessed at 87%. Images falsely classified as crystal-positive variously contain speckled precipitate resembling microcrystals, skin effects or genuine crystals falsely labeled by the human expert. Many images falsely classified as crystal-negative variously contain very fine crystal features or dendrites lacking straight edges. Characterization of these misclassifications suggests directions for improving the method.

关键词：醛糖酮糖异构酶类/化学人工智能结晶/仪器和设备结晶/方法图像处理计算机辅助/分类微量化学/仪器和设备微量化学/方法纳米技术结果可重复性机器人/方法

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Mixing processes in a zigzag microchannel: Finite element simulations and optical study

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ANALYTICAL CHEMISTRY 2002年第16期74卷 4279-4286页

作者： Mengeaud, V Josserand, J Girault, HH Ecole Polytech Fed Lausanne Lab Electrochim Phys & Analyt CH-1015 Lausanne Switzerland

A finite element model has been used in order to study the mixing process of species in a 100-mum-wide zigzag microchannel integrating a "Y" inlet junction. The distribution of the concentration was obtained by solving successively the Navier-Stokes equation and the diffusion-convection equation in the steady state form. Because of the large range of Reynolds numbers studied (1 < Re < 800), the 2D diffusion-convection simulations are carried out with high diffusion coefficients. The results illustrated the effects of both flow rate and. channel geometry on hydrodynamics and mixing efficiency. Below a critical Reynolds number of similar to80, the mixing is entirely ensured by, molecular, diffusion. For higher Reynolds numbers, simulations revealed the mixing contribution of laminar flow recirculations. This effect increases for lower values of diffusion coefficients. Experimental studies on the mixing of species at different flow rates are reported showing the same hydrodynamic tendency.

关键词：设备设计/方法有限元分析微量化学/仪器和设备小型化流变学

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Pretransitional effects in dimyristoylphosphatidylcholine vesicle membranes: Optical dynamometry study

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BIOPHYSICAL JOURNAL 2000年第1期79卷 340-356页

作者： Dimova, R Pouligny, B Dietrich, C CNRS Ctr Rech Paul Pascal F-33600 Pessac France Univ Sofia Fac Chem Lab Thermodynam & Physicochem Hydrodynam Sofia 1164 Bulgaria Univ N Carolina Dept Cell Biol & Anat Chapel Hill NC 27599 USA

We used micron-sized latex spheres to probe the phase state and the viscoelastic properties of dimyristoylphosphatidylcholine (DMPC) bilayers as a function of temperature. One or two particles were manipulated and stuck to a DMPC giant vesicle by means of an optical trap. Above the fluid-gel main transition temperature, T-m congruent to 23.4 degrees C, the particles could move on the surface of the vesicle, spontaneously (Brownian motion) or driven by an external force, either gravity or the laser beam's radiation pressure. From the analysis of the particle motions, we deduced the values of the membrane hydrodynamic shear viscosity, eta(s), and found that it would increase considerably near T-m. Below T-m, the long-distance motion of the particles was blocked. We performed experiments with two particles stuck on the membrane. By optical dynamometry, we measured the elastic resistance of the membrane to a variation in the interparticle distance and found that it would decrease considerably (down to zero) when the temperature was increased to T-m. We propose an interpretation relating the elastic response to the membrane curvature modulus, k(C). in this scheme, the two-bead dynamometry experiments provide a direct measurement of k(C) in the P-beta' phase of lipid bilayers.

关键词：生物物理学二肉豆蔻磷脂酰胆碱/化学弹性凝胶类/化学脂双层/化学脂质体/化学膜人工微量化学/仪器和设备微量化学/方法微球体温度黏度

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High-throughput and ultra-high-throughput screening: solution- and cell-based approaches

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CURRENT OPINION IN BIOTECHNOLOGY 2000年第1期11卷 47-53页

作者： Sundberg, SA Caliper Technol Corp Mountain View CA 94043 USA

The trend towards assay miniaturization for high-throughput and ultra-high-throughput screening continues to spur development of homogeneous, fluorescence-based assays in higher density, smaller volume microplate formats. Recently, first-generation micro;fluidic devices have been designed for performing continuous-flow biochemical and cell-based assays. These devices provide orders-of-magnitude reduction in reagent consumption, and offer the potential for implementing high-throughput screening in formats that integrate up-front compound handling with unique assay functionality.

关键词：生物技术/仪器和设备生物技术/方法细胞/酶学细胞/代谢药物评价临床前/方法酶类/代谢荧光配体微量化学/仪器和设备微量化学/方法蛋白质结合溶液动物人类

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Microscale sample preparation - The demand for microscale analysis has stimulated the development of new solid phase formats in sample preparation.

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NATURE BIOTECHNOLOGY 2000年第1期18卷 104-105页

作者： Pluskal, MG usmgp@***

The demand for microscale analysis has stimulated the development of new solid phase formats in sample *** interest in studying complex patterns of proteins in cells and tissues has led to new developments in analytical technologies. This interest in following changes in the cellular protein phenotype, termed proteomics, has generated a need for rapid and accurate protein identification. Such methods are derived from high-resolution separation approaches, like two-dimensional gel electrophoresis followed by protease digestion. The characterization methodology of choice is no longer Edman-based sequencing, but rather the more rapid and sensitive mass spectrometry (MS) approach. Both methods, however, are compromised by dirty and contaminated samples. Additionally, in MS, much smaller sample volumes and a higher concentration of analyte are required. To meet these challenges, new sample preparation processes are being developed for microscale volumes in miniaturized formats. At a recent meeting^1, microscale methodologies and their increasing application to drug discovery, combinatorial chemistry, and protein/peptide characterization studies were described. This article reviews the development of new formats of microscale sample preparation devices.

关键词：色谱法高压液相/仪器和设备色谱法高压液相/方法色谱法高压液相/发展趋势微量化学/仪器和设备微量化学/方法微量化学/发展趋势寡核苷酸类/分析寡核苷酸类/化学寡核苷酸类/分离和提纯肽类/分析肽类/化学肽类/分离和提纯聚合物蛋白质组标本制备/仪器和设备标本制备/方法标本制备/发展趋势

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A 96-well microfiltration assay for measurement of total clottable fibrinogen

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THROMBOSIS AND HAEMOSTASIS 1999年第2期81卷 264-267页

作者： Dempfle, CE Keller, A Argirion, S Heene, DL Univ Heidelberg Mannheim Hosp Dept Med 1 D-6800 Mannheim Germany

In clinical routine use, fibrinogen is measured by clotting-time methods, or by clot turbidity in photometric prothrombin time determination. For calibration of these assays measurement of total thrombin-clottable protein has been recommended. We have now developed a microfiltration assay for total thrombin-clottable protein. Plasma samples were mixed with thrombin in a 96-well microfiltration device. After clot formation, the fluid was extracted by vacuum suction, and fibrin adherent to the filter membranes washed with buffer. Membrane segments with adherent fibrin were recovered from the 96-well manifold with a punch and transferred to tubes containing denaturing buffer solution. After dissolution of fibrin, protein concentration was determined by optical absorption at 280 nm, The microfiltration assay displayed a high correlation with the total clottable protein method (R = 0.95), and fibrinogen antigen (r = 0.96). Correlation with clotting time assays, and PT-derived fibrinogen in 150 clinical plasma samples was in the range of r = 0.84 to r = 0.97. Intraassay and day-to-day variability of the assay was comparable to the conventional total clottable fibrinogen assay. The novel microfiltration assay appears to be well suited for measurement of large series of samples for calibration, screening purposes, and clinical trials.

关键词：血液凝固/药物作用血液凝固试验/仪器和设备血蛋白质类/化学校准纤维蛋白纤维蛋白原降解物/药理学纤维蛋白原/分析纤维蛋白原/化学过滤/仪器和设备膜人工微量化学/仪器和设备凝血酶/药理学人类

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用空气—乙炔火焰原子吸收分光光度法测定人体结石中的铜、铁、锌、镁

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宁夏医学院学报 1987年第3期 12-16页

作者：钱立群党花娥郎惠云谢志海宁夏医学院卫生系卫生分析化学教研室宝鸡市渭滨卫生防疫站西北大学化学系

用HNO3—HCIO4或HNO3—HCIO4—H2O2体系进行样品处理后,以空气—乙炔火焰原子吸收分光光度法测定人体结石中之铜、铁、锌和镁。该法快速、简便,精密度较高,回收率也较为理想。检测了样品溶液中各种其它有关离子的干扰,发现干扰是轻微的... 详细信息

用HNO3—HCIO4或HNO3—HCIO4—H2O2体系进行样品处理后,以空气—乙炔火焰原子吸收分光光度法测定人体结石中之铜、铁、锌和镁。该法快速、简便,精密度较高,回收率也较为理想。检测了样品溶液中各种其它有关离子的干扰,发现干扰是轻微的。本法与其它相关技术结合,在定量评估结晶态、特别是人体结石实验室分析检测上具有应用的可行性。

关键词：胆结石/分析肾结石/分析膀胱结石/分析微量化学/仪器和设备分光光度测定法,原子吸收乙炔微量元素/分析结晶/分析

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ION PROBE STUDY OF FLUORINE GRADIENTS IN OUTERMOST LAYERS OF HUMAN ENAMEL

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JOURNAL OF DENTAL RESEARCH 1976年第6期55卷 980-990页

作者： PETERSSON, LG ODELIUS, H LODDING, A LARSSON, SJ FROSTELL, G UNIV LUND SCH DENT DEPT CARDIOL S-21421 MALMO SWEDEN CHALMERS UNIV TECHNOL CTR MAT SCI S-40220 GOTHENBURG 5 SWEDEN

F concentrations in the outermost layers of human tooth enamel were studied after exogenous treatment with the aid of a secondary ion microanalyzer. Concentration profiles were recorded in continuous sputtering analysis from the surface down to a depth of about 0.3 .mu.m. Samples previously subjected to topical fluoride treatment were compared with reference specimens. In some samples, the results were compared with those obtained at greater depth by macroscopic etching analysis.

关键词：酸蚀牙氟化钙/分析牙釉质/分析牙釉质/代谢氟化物外用/代谢氟/分析质谱分析法/方法微量化学/仪器和设备漱口药青少年儿童人类

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