Assembly of sugars on polystyrene plates: a new facile microarray fabrication technique

The work presented herein is a new noncovalent glycoarray assembly method for microplates created by simply mixing together an isocyanate-containing C₁₄-hydrocarbon and an amine-containing carbohydrate. 2-Aminoethyl-β-d-galactopyranoside (1) was utilized in model studies and product formation was detected by both ESI-MS and lectin binding. The method has been further extended to array complex carbohydrates.     

Multiple-detector responses or multiple-retention times: what is more informative for gas chromatography peak identification?

Multiple-separation and -detection are two approaches applied at the identification of analytes in chromatography. Using them depends on the physico-chemical properties and elemental content of the analytes. When physico-chemical properties are similar multiple-separation gives better opportunities for the identification. In this case, the efficiency of the columns is very important. When analytes contain some characteristic groups as--NO2, halogen, or nitrogen atoms then multiple-detection will be more useful. The sensitivity and/or selectivity of the detectors increase reliability of identification significantly.     

ATPases as Multi-Response Sensing System for Various Organic and Inorganic Analytes

Summary. The possibility of using synaptic plasma membrane (SPM) enzymes Na⁺/K⁺-ATPase and Mg²⁺-ATPase, isolated from rat brain, as a biological component of multi-response sensing system for detection of different compounds (alkaline and heavy metal salts, organic compounds) was studied. The method is based on the spectrophotometric determination of inorganic ortho-phosphate (P_i) that serves as a measure of the enzymatic activity in the presence of various analytes. The concentration of P_i, liberated by enzyme catalysed hydrolysis of adenosinetriphosphate (ATP), was followed spectrophotometrically, by single exposure to analytes or in the mixture. P_i was dose dependent on the analyte concentration. Alkaline elements (Na, K, Mg), heavy metals (Pb, Cd, Hg, Cu, Fe, Co, Zn), toxic organic compounds (pyridine, urea, chlorpyrifos), and some drugs (digoxin, gitoxin) showed diverse effects, inducing the inhibition or stimulation of the enzymes activity. Development of simple test method for simultaneous detection of the investigated analytes based on the variation of medium assay composition was discussed.     

Non-destructive testing of tubes using a time reverse numerical simulation (TRNS) method

A method for the detection of defects in cylindrical structures and the determination of their positions and orientations is presented in this paper. The scattered field, which is generated by the interaction of excited guided waves with a defect, is evaluated with an approach named time reverse numerical simulation method (TRNS). Since the excited waves and the scattered field propagate along the sample, the time-consuming scanning of the whole tube can be eliminated. The scattered displacement field is measured in three dimensions over time with a laser vibrometer at different locations distributed equally around the circumference at a fixed axial coordinate far away from the defect. Instead of analyzing the complicated time signals directly, they are played back in time. If the recorded displacement histories of the scattered field are reversed in time and played back in an identical structure, the waves travel back the same path and interfere to a maximum at their origin. The result is an amplitude increase at the position of the defect where the scattered field was generated. Instead of playing back the recorded time signals in an experiment, this step is replaced by a numerical simulation. Only this enables the visualization and detection of the amplitude increase. As long as the simulation is of high accuracy, the position of the maximum interference corresponds exactly to the location of the defect in the experiment, although no defect is implemented in the simulation.     

New type of biosensor based on magnetic nanoparticle detection

A new type of biosensor has been developed based on detection of nanosized superparamagnetic particles that serve as labels in bioreactions. The method is based on non-linear magnetic material detection by a magnetic field having components at two frequencies f₁ and f₂. The response is measured at the combinatorial frequencies f_i=mf₁+nf₂, where m and n are integers, e.g., f_i=f₁±2f₂. Several highly sensitive readers of superparamagnetic particles have been designed and used for development of various formats of immunoassays, including those compatible with immunoconcentration and magnetic enrichment of antigens.     

Accurate, high-order representation of complex three-dimensional surfaces via Fourier continuation analysis

We present a new method for construction of high-order parametrizations of surfaces: starting from point clouds, the method we propose can be used to produce full surface parametrizations (by sets of local charts, each one representing a large surface patch – which, typically, contains thousands of the points in the original point-cloud) for complex surfaces of scientific and engineering relevance. The proposed approach accurately renders both smooth and non-smooth portions of a surface: it yields super-algebraically convergent Fourier series approximations to a given surface up to and including all points of geometric singularity, such as corners, edges, conical points, etc. In view of their C^∞ smoothness (except at true geometric singularities) and their properties of high-order approximation, the surfaces produced by this method are suitable for use in conjunction with high-order numerical methods for boundary value problems in domains with complex boundaries, including PDE solvers, integral equation solvers, etc. Our approach is based on a very simple concept: use of Fourier analysis to continue smooth portions of a piecewise smooth function into new functions which, defined on larger domains, are both smooth and periodic. The “continuation functions” arising from a function f converge super-algebraically to f in its domain of definition as discretizations are refined. We demonstrate the capabilities of the proposed approach for a number of surfaces of engineering relevance.     

基于CCD的无接触式的物体测量

基于CCD的物体测量平台，首先对物体图像进行预处理，继而利用Canny算子提取物体边缘，再通过本文改进的Hough变换实现对被测物体边界直线检测和重构，最后通过多项式插值算法实现物体像素尺寸到物体实际尺寸的转换．实验证明，此方法能够实现无接触式物体尺寸较高精度的测量．     

X-ray Peltier cooled detectors for X-ray fluorescence analysis

The recent results on development of X-ray Si(Li), Si-planar and CdTe p-i-n detectors cooled by Peltier coolers for fabrication of laboratory and portable XRF analysers for different applications are discussed.

Low detection limits of XRF analysers are provided by increasing of detectors sensitive surface; improvement of their spectrometrical characteristics; decreasing of front-end-electronics noise level; Peltier coolers and vacuum chambers cooling modes optimization.

Solution of all mentioned tasks allowed to develop Peltier cooled detectors with the following performances:

Full-size image

Advantages and disadvantages of all types of detectors for X-ray fluorescence analysis are compared. Spectra are presented. Application of different XRF analysers based on developed detectors in medicine, environmental science, industry, cryminalistics and history of art are demonstrated.     

剖面不变性与非局部扰动电子温度响应

在ＴＦＴＲ及ＴＥＸＦ等装置上观测到的边界电子冷脉冲的输运现象是通常基于局部热导的瞬态输运理论所无法解释的。利用一个与电子温度剖面不变性相「容的且与在ρ＝ρＬ（ρＬ≈０．７～０．８）处的局部电子热导相关的非局部电子热导模型来描述边界冷脉冲引起的电子温度变化的瞬态过程，发现此模型可定性地解释边界冷脉冲实验现象的几乎所有主要特征。