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1
Content available remote Development and validation of UPLC–MS/MS method for determination of eupatilin in rat plasma and its application in a pharmacokinetics study
Geng P., Luo X., Peng X., Lin Z., Chen W., Zhang J., Wen C., Hu L., Hu S.
Acta Chromatographica
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2018
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Vol. 30, no. 4
231--235
EN
Eupatilin, mainly derived from Artemisia asiatica (Asteraceae), is an O-methylated flavone with various bioactivities. In the present study, a validated ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was established for the quantification of eupatilin in rat plasma with the internal standard (IS) of tussilagone and the protein precipitation of plasma samples was performed using acetonitrile–methanol (9:1, v/v). The eupatilin and IS were eluted separately on a UPLC BEH C18 column (2.1 mm × 100 mm, 1.7 μm) with the gradient mobile phase consisted of 0.1% formic acid and acetonitrile. The protonated analytes were quantified by multiple reactions monitoring (MRM) mode with an electrospray ionization (ESI) source operated in positive ion mode. The calibration plots were found to be linear over the range from 2 to 1000 ng/mL for eupatilin in rat plasma. Both of the intra-day and inter-day precision variations (RSDs) were ≤13%. The recoveries of eupatilin in rat plasma were between 83.7% and 94.6%, and the accuracy of the method ranged from 95.8% to 107.6%. In addition, the validated method was applied to pharmacokinetic study of eupatilin after an intravenous dose of 2 mg/kg to rats.
2
Content available Study on the Initiation Capacities of Conical Ring Booster Pellets
Hu L., Hu S., Cao X., Li J.
Central European Journal of Energetic Materials
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2014
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Vol. 11, no. 3
335--348
EN
The insensitive main charge explosive is becoming an important part of modern weapon development. Insensitive main charge explosives generally have a high critical initiation pressure. The detonation pressure of a traditional cylindrical booster pellet is constant at a specific density and consequently has insufficient energy output to reliably initiate an insensitive main charge explosive. To ensure that this requirement could be achieved, the conical ring booster pellet was designed and optimized. Eight-point-synchronous explosive circuits were designed as appropriate to the sizes of the four booster pellets. The initiation processes of the four conical booster pellets equipped with the eight-point circuit were simulated using ANSYS/LY-DYNA software. The experimental measurements were performed in order to test the initiation capacities of these conical booster pellets. The results demonstrated that their initiation capacities are much better than the initiation capacity of a cylindrical booster pellet. The optimum size of the conical ring booster pellet is when the ratio of the inner to the upper diameter is 0.52, the ratio of the inner to the lower diameter is 0.44, and the ratio of the height to the lower diameter is 0.50.
3
Content available Initiation Capacity of a New Booster Pellet
Hua L., Hu S., Cao X.
Central European Journal of Energetic Materials
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2014
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Vol. 11, no. 1
157--170
EN
Insensitive munitions improve the survivability of both weapons and their associated platforms. All weapon systems contain an explosive train which needs to meet the insensitive munitions criteria but also to reliably initiate the main charge explosive. The traditional cylindrical booster pellet has insufficient energy output to reliably initiate an insensitive main charge explosive. To ensure that this requirement can be achieved, a new highly effective booster charge structure was designed. New booster pellets of four different sizes were investigated by numerical simulation and the one with the most powerful output was selected for experimental study. The results show that the new booster pellet has more initiation capacity than a cylindrical booster pellet with the same mass and pressed density. The convergence pressure of the new booster pellet is much higher than that of a cylindrical booster pellet with the same density.
4
Content available remote SURE-Based Projections Onto Convex Sets for Image Restoration
Deng C., Tian W., Wang S., Hu S., Rao W., Li Y.
Przegląd Elektrotechniczny
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2013
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R. 89, nr 5
167-170
EN
Projections onto convex sets (POCS) algorithms have been widely used for image restoration problem. However, the relaxation parameter of POCS is strongly data-dependent and difficult to tune. In this work we focus on optimally selecting such parameter in POCS algorithm for image restoration. A stein’s unbiased risk estimate (SURE) based POCS (SPOCS) for image restoration algorithm is proposed, in which SURE is used to determine an optimal value. Finally, the effectiveness of the optimality of the proposed parameter selection is tested by image restoration experiments.
PL
W artykule przedstawiono metodę optymalnego doboru parametru relaksacji dla algorytmu POCS, służącego do odtwarzania obrazów. W proponowanym rozwiązaniu (SPOCS) zastosowano estymator Stein’a (SURE), służący do wyznaczenia optymalnej wartości współczynnika lambda. Działania algorytmu zostało zbadane eksperymentalnie.
5
Content available remote The study on pH gradient control in solution for driving bacteria
He B., Wang Z., Xu C., Shen R., Hu S.
Biocybernetics and Biomedical Engineering
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2013
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Vol. 33, no. 2
88--95
EN
Medical applications are the most impactful areas of microrobotics, such as targeting tumoral lesions for therapeutic purposes, minimally invasive surgery (MIS) and highly localized drug delivery. However, miniaturization of the power source with an effective on board controllable propulsion system has prevented the implementation of such mobile robots. Flagellated chemotactic bacteria can be used as an effective integrated propulsion system for microrobots. In this paper, we study the pH gradients control in solution for driving bacteria. The swimming property of flagellar bacteria and mechanism of forming the pH gradient field in solution are discussed. By experiments, we found that the pH gradient field distribution in solution is mainly related to the electrode shape. And the input voltage value can control the stable time of the pH gradient field, while it has no effect on the distribution of the field. The electric potential distribution is analyzed by simulation with COMSOL Multiphysics. The simulation results are consistent with the experiment results, which indicate that the bacteria movement can be controlled by the electrodes' shape and the input voltage.
6
Content available Study on the Initiation Capacities of Two Booster Pellets
Hu L., Hu S., Cao X.
Central European Journal of Energetic Materials
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2012
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Vol. 9, nr 3
261-272
EN
The appearance of insensitive main charges has created new requirements in the booster pellets of the detonation train, specifically, the output of the booster pellet must be strong enough to initiate the insensitive main charge. Traditional cylindrical booster pellets have great difficulty in meeting the demands of the insensitive main charge for reliable detonation. A four-point-synchronous explosive circuit and an eight-point-synchronous explosive circuit were designed to initiate two booster pellets, designed on the basis of shock initiation theory and effective charge theory, as well as the shaped charge effect theory. The results show that booster pellet 1 and booster pellet 2, under multi-point-synchronous explosive circuits, can initiate standard main charge pellets with less explosive mass than an ordinary cylindrical booster pellet. The initiation capacity of booster pellet 2 is better than that of booster pellet 1.
7
Content available remote High focusing of radially polarized Bessel-modulated Gaussian beam
Gao X., Gao M., Hu S., Guo H., Wang J., Zhuang S.
Optica Applicata
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2010
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Vol. 40, nr 4
965--974
EN
The focusing properties of radially polarized Bessel-modulated Gaussian (QBG) beam are theoretically investigated in detail by vector diffraction theory. The QBG beam contains an optical vortex. Calculation results show that the intensity distribution in focal region of radially polarized QBG beam can be altered considerably by changing beam parameter and the topological charge of the optical vortex. Beam parameter can induce remarkable focus evolution in axial direction. While topological charge adjusts intensity distribution more significantly in transverse direction, for instance, one focal spot changes into one ring pattern. And some novel focal patterns may occur, including two-peak focus, one ring focus, two-ring focus, three-ring focus, and even dark hollow focus, which is very important in optical tweezers technique.
8
Content available remote Oxidation of activated carbon fibre and its adsorption of amylase
Li Y., Hu S.
Materials Science Poland
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2009
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Vol. 27, No. 2
453--461
EN
Activated carbon fibre was oxidized by combustion of nitrocellulose and oxidation with nitric acid to introduce the nitrogen and oxygen groups on its surface. The pore structure and chemical groups were investigated by nitrogen adsorption and FTIR. The result showed that the pore structure and surface morphology were not much affected but amide and hydroxyl groups could be introduced after oxidation. The adsorption capacity of amylase was markedly increased, and the hydrolysis activity of starch was maintained after 3 runs.
9
Content available remote Iterative estimators of parameters in linear models with partially variant coefficients
Hu S., Meinke K., Chen R., Huajiang O.
International Journal of Applied Mathematics and Computer Science
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2007
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Vol. 17, no 2
179-187
EN
A new kind of linear model with partially variant coefficients is proposed and a series of iterative algorithms are introduced and verified. The new generalized linear model includes the ordinary linear regression model as a special case. The iterative algorithms efficiently overcome some difficulties in computation with multidimensional inputs and incessantly appending parameters. An important application is described at the end of this article, which shows that this new model is reasonable and applicable in practical fields.
10
Content available remote Application of carbon glacy electrode coated with multi-wall nanotube film for determination of bisphenol A in plastic waste samples
Lü S., Fei J., He Q., Hu S.
Chemia Analityczna
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2004
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Vol. 49, No. 5
607-617
EN
A sensitive electroanalytical procedure for determination of bisphenol A at a glassy carbon electrode (GCE) modified with a multi-wall carbon nanotube (MWCNT) film has been developed. MWCNT film modified GCE exhibited excellent electrochemical behavior towards the oxidation of bisphenol A. At the accumulating potential of 0.3 V, it was preconcentrated at the electrode surface. After 10 s quiescent time the potential was linearly scanned to the anodic direction from 0.3 V to 0.9 V. The oxidation peak was recorded at approximately 0.58 V. Experimental parameters, such as the amount of MWCNT on GCE surface, the pH of the supporting electrolyte, and the scan rate have been optimised, since they might have influenced oxidation current of bisphenol A. Under the optimum conditions the magnitude of the current response of bisphenol A changed linearly with its concentration from 5.0 × 10-8 to 2.0 × 10-5 mol L-1. A detection limit of 2.0 × 10-8 mol L-1 was found. The proposed procedure was applied to the determination of bisphenol A in various samples of plastic wastes.
PL
Opracowano czułą metodę elektroanalityczną do oznaczania bisfenolu A przy pomocy elektrody z węgla szklistego zmodyfikowanej błonkązwielościanowych węglowych nano-rurek. Elektroda ta wykazuje bardzo dobrą zdolność utleniania bisfenolu, który przy potencjale 0,3 V można zatężyć na jej powierzchni. Po zatężeniu bisfenolu A i zarejestrowaniu woltamperogramu w kierunku potencjałów dodatnich, pojawia się pik anodowy przy ok. 0,58 V. W pracy zoptymalizowano takie parametry jak: grubość błonki, pH roztworu i szybkość zmian potencjału. W warunkach optymalnych pik bisfenolu A zmienia się liniowo ze stężeniem w zakresie od 5.0 * 10(-8) do 2.0 x 1O(5) mol L(-1).Granicę wykrywalności określono na 2.0 x 10(-8) mol L(-1). Opracowaną metodę zastosowano do oznaczania bisfenolu A w odpadach plastikowych.
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