用于数字条纹轮廓术的一种基于广义分析模型的后滤波方法

由于数字投影和采集系统的非线性失真,传统的方法通常需对采集到的条纹进行低通或带通滤波从而抑制高次谐波并获取基频分量。基于广义分析模型针对数字条纹轮廓术提出一种对测量后的物体形貌进行后滤波的算法,消除了非线性失真对测量结果所造成的影响并提高了数字条纹轮廓术的测量精度。论述了条纹轮廓术的原理和广义分析模型,分析推导出后滤波算法。仿真和实验结果表明,后滤波方法能够快速准确地实现基于数字投影的三维形貌重建。     

Mechanism of adhesion between protein-based hydrogels and plasma treated polypropylene backing

We studied the mechanism of adhesion between N₂ plasma treated polypropylene (PP/N₂) backing and a hybrid hydrogel (HG) produced by chemical crosslinking between poly(ethylene glycol) and soy albumin. The work of adhesion, measured by peel testing, was found to be 25 times higher for PP/N₂ compared to untreated PP (≈5.0 J/m² versus ≈0.2 J/m²). In order to understand the adhesion mechanism, we performed a detailed analysis of the surface chemical composition of PP and PP/N₂ using X-ray photoelectron spectroscopy (XPS), chemical derivatization and attenuated total reflectance infra-red (ATR-IR) measurements. The results confirm incorporation of different nitrogen- (amine, amide,…) and oxygen- (hydroxyl, carboxyl,…) containing chemical groups on the PP/N₂ surface. The derivatized functions were primary amine, hydroxyl, carboxyl and carbonyl groups. Chemical derivatization reactions validated the XPS results (except for carbonyl groups), and they clearly underlined the essential role of primary amine groups in the adhesion process. In fact, after derivatization of the amine functions, the work of adhesion was found to be 0.41 ± 0.12 J/m². Participation of amine groups in the formation of covalent bonds at the interface between PP/N₂ and HG was directly confirmed by ATR-IR measurements.     

Behaviors of the MS2 virus and related antibodies in capillary isoelectric focusing with whole-column imaging detection

Capillary isoelectric focusing (CIEF) has potential importance for the study of viruses. CIEF with whole-column imaging detection (WCID) is a novel CIEF mode, providing the advantages of high resolution, high speed, and easy method development. To facilitate the application of CIEF-WCID to the immunoassay of viruses, a basic knowledge of related aspects is necessary. In this study, the MS2 bacteriophage was used as a virus model, and the behaviors of MS2 and related antibodies in CIEF were investigated with UV absorbance-WCID and laser-induced fluorescence (LIF)-WCID. The adsorption of the virus and antibodies on the capillary wall was found to be the critical issue in method development. Addition of salt was found to be an effective way to reduce the adsorption and to improve peak shape. The formation of an immunocomplex, which forms the basis of an immunoassay, was monitored with CIEF-WCID. In comparison with UV-WCID, LIF-WCID was advantageous due to its higher detection sensitivity and the elimination of precipitation. Utilization of the noncovalent fluorescent dye, NanoOrange, was demonstrated to be a potential approach for the fluorescent labeling of the virus model and antibody and the associated immunocomplex. The change in microheterogeneity during the immune interactions at different ratios was also observed.     

An improved method for proteomics studies in C. elegans by fluorogenic derivatization, HPLC isolation, enzymatic digestion and liquid chromatography--tandem mass spectrometric identification

An improved method for proteomics studies, which includes the fluorogenic derivertization of protein mixtures with 7-chloro-4-(dimethylaminoethylaminosulfonyl)-2,1,3-benzoxadiazole (DAABD-Cl), followed by HPLC isolation, enzymatic digestion and identification of the derivatized proteins by HPLC-electrospray ionization (ESI)-MS/MS with the probability-based protein identification algorithm, identified 103 proteins in the soluble extract (10 microg protein) of Caenorhabditis elegans.     

A Polynomial Cutting Surfaces Algorithm for the Convex Feasibility Problem Defined by Self-Concordant Inequalities

Consider a nonempty convex set in ^m which is defined by a finite number of smooth convex inequalities and which admits a self-concordant logarithmic barrier. We study the analytic center based column generation algorithm for the problem of finding a feasible point in this set. At each iteration the algorithm computes an approximate analytic center of the set defined by the inequalities generated in the previous iterations. If this approximate analytic center is a solution, then the algorithm terminates; otherwise either an existing inequality is shifted or a new inequality is added into the system. As the number of iterations increases, the set defined by the generated inequalities shrinks and the algorithm eventually finds a solution of the problem. The algorithm can be thought of as an extension of the classical cutting plane method. The difference is that we use analytic centers and convex cuts instead of arbitrary infeasible points and linear cuts. In contrast to the cutting plane method, the algorithm has a polynomial worst case complexity of O(Nlog 1/) on the total number of cuts to be used, where N is the number of convex inequalities in the original problem and is the maximum common slack of the original inequality system.