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1

Analysis of polyphenols in Valeriana wallichii DC by capillary electrophoresis with amperometric detection

Chu Q, Zhang H., Zhang D., Ye J.

Acta Chromatographica

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2010

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Vol. 22, no. 4

623--635

EN

High-performance capillary electrophoresis with amperometric detection (CE-AD) has been used for analysis of eight bioactive components of the leaves, stems, and roots of Valeriana wallichii DC, after a relatively simple extraction procedure with ethanol. Under the optimum conditions, the eight components can be well separated or (apigenin and luteolin) separated nearly to baseline within 23 min by use of 50 mM borax (pH 9.2) as running buffer and a separation potential of 16 kV. Linearity was excellent over two orders of magnitude of concentration and detection limits ( S/N = 3) ranged from 1.7 × 10 −7 to 1.8 × 10 -8 g mL -1. This method was used for comparison of the concentrations of the bioactive compounds in different parts of the plant on the basis of their electropherograms or ‘characteristic electrochemical profiles’. Assay results were satisfactory.

2

Capillary electrophoresis-electrochemiluminescence method for simultaneous detection of azithromycin, roxithromycin and erythromycin ethylsuccinate

Wang Z., Yang Z., Ye J., Tan G., Xu H., Liu Y.

Chemia Analityczna

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2009

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Vol. 54, No. 5

883-894

EN

In this paper, a capillary electrophoresis-electrochemiluminescence method for simulta- ' neous detection of three macrolide antibiotics: azithromycin (ATM), roxithromycin (RTM) and erythromycin ethylsuccinate (ETMES) has been presented. The method is based upon the enhancement effect of these compounds on electrochemiluminescence of tris(2,2- , bipyridyl) ruthenium(II) (Ru(bpy)32+). Under the optimized conditions, complete separation of ATM, RTM and ETMES was achieved within 6 min using 20 mmol L -1phosphate buffer of pH 7.3 as a background electrolyte and applying a separation voltage of 20 kV. Detection limits were 0.1 μmol L-1 for ATM, 0.2 μmol L-1 for RTM, and 0.4 umol L-1 for ETMES (S/N = 3). Relative standard deviations for all analytes were below 5%. The proposed method has been successfully applied to the determination of the content of the studied compounds in spiked human plasma and urine samples.

PL

Opracowano metodę elektroforezy kapilarnej z użyciem elektrochemiluminescencji do ., równoczesnego oznaczania trzech antybiotyków makrolidowych: azytromycyny (ATM), roksytromycyny (RTM) oraz etylobursztynianu erytromycyny (ETMES). Metoda wykorzystuje wzmocnienie przez badane antybiotyki elektrochemiluminescencji tris(2.2-bipi-rydylo)rutenu (Ru(bpy)+2. W optymalnych warunkach w czasie 6 min uzyskano całkowite rozdzielenie ATM, RTM i ETMES stosując 20 mmol L-1 bufor fosforanowy o pH 7,3 jako elektrolit podstawowy, przy napięciu 20 kV. Granica wykrywalności ATP, RTP i ETMES ' wynosiła odpowiednio: 0,1; 0,2 i 0,4 μ mol L-1(S/N = 3). Względne odchylenie standardowe wszystkich elektrolitów było pniżej 5%. Proponowana metoda została z powodzeniem zastosowana do oznaczania zawrtości badanych związków w próbkach krwi i moczu.

3

Simplification of 3D head mesh acquired from laser scanner

Ye J.

Machine Graphics and Vision

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2002

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Vol. 11, No. 4

489-498

EN

Complex triangle meshes arise extensively in computer graphics. Such meshes greatly exceed the processing power of modern computer hardware and need to be simplified. The purpose of this paper is to simplify a 3D color human head mesh acquired from a 3D laser scanner. It is more important to keep the boundaries and quality of the sense organs which are the region of interest, while it is reasonable to simplify other features of the head aggressively, such as hair, face and neck. Based on these heuristics, we present a novel vertex merging mesh simplification algorithm based on region segmentation. The algorith can be divided into two stages: segmentation and simplification. First, the 3D color head mesh is segmented into different head parts with respect to both geometry and attributes, then vertices are classified into region-inner vertices and region-boundary vertices. Second, interative vertex merging is applied using region-weighted error metric in order to implement controllable simplifications. Results of several experiments are shown, demonstrating the potential of our method for a 3D color head mesh. Also, our method is resistant to noise in practical applications.