In vitro metabolism study of Strychnos alkaloids using high‐performance liquid chromatography combined with hybrid ion trap/time‐of‐flight mass spectrometry

In this report, the in vitro metabolism of Strychnos alkaloids was investigated using liquid chromatography/high‐resolution mass spectrometry for the first time. Strychnine and brucine were selected as model compounds to determine the universal biotransformations of the Strychnos alkaloids in rat liver microsomes. The incubation mixtures were separated by a bidentate‐C₁₈ column, and then analyzed by on‐line ion trap/time‐of‐flight mass spectrometry. With the assistance of mass defect filtering technique, full‐scan accurate mass datasets were processed for the discovery of the related metabolites. The structural elucidations of these metabolites were achieved by comparing the changes in accurate molecular masses, calculating chemical component using Formula Predictor software and defining sites of biotransformation based upon accurate MSⁿ spectral information. As a result, 31 metabolites were identified, of which 26 metabolites were reported for the first time. These biotransformations included hydroxylation, N‐oxidation, epoxidation, methylation, dehydrogenation, de‐methoxylation, O‐demethylation, as well as hydrolysis reactions. Copyright © 2013 John Wiley & Sons, Ltd.     

试论精细化管理在少数民族大学生日常管理中的应用

基于少数民族大学生的特殊性，综合运用文献资料法、调查研究法、实证分析法等，在深入分析“少数民族大学生精细化日常管理”的基本内容以及特征的基础上，对精细化管理在少数民族大学生日常管理中的操作路径以及在实施过程中的误区进行了剖析。认为少数民族大学生日常管理的基本路径主要应该从三方面入手：一要关照细节；二要摆脱传统的计划经济管理思维的束缚；三要把精细化管理与目标管理、能本管理交叉使用。     

Robustness of Pathwise Stability of Semilinear Perturbed Stochastic Evolution Equations

Abstract

The purpose of this paper is to investigate pathwise stability for certain Hilbert space-valued stochastic evolution equations. We are especially interested in the robustness analysis of perturbed stochastic differential equations in infinite dimensions. Sufficient conditions are established to ensure the almost surely stable decay of the given stochastic systems. Lastly, a corollary and corresponding example are studied to illustrate our theory.     

In vivo metabolism study of bergenin in rats by HPLC‐QTOF mass spectrometry

Bergenin is the major component of Ardisia creanta sims and Rodgersia sambucifolia hemsl with many biological activities. Although bergenin has been used to treat human diseases in China for man years, there is no report regarding its metabolism. This is the first report to separate and identify the metabolites of bergenin in vivo. In the study, HPLC/Q‐TOF‐MS/MS was used to investigate the metabolites of bergenin in vivo by analyzing the rat body fluid and feces samples. Three metabolites of bergenin were finally identified by the TIC chromatograms, and the structures were also confirmed by their MS² spectra. Copyright © 2013 John Wiley & Sons, Ltd.     

Evaluation of calcipotriol transdermal permeation through pig,rat and mouse skin using liquid chromatography–tandem mass spectrometry

A rapid and sensitive liquid chromatography–tandem mass spectrometric method to evaluate the permeation and retention of calcipotriol in excised samples of pig, rat and mouse skin after application of a calcipotriol ointment has been developed and validated. After sample preparation of ointment, skin homogenate and receptor medium by liquid–liquid extraction, chromatography was performed on an Extend‐C₁₈ column using isocratic elution. Detection was by electrospray ionization in the negative ion mode using multiple‐reaction monitoring of the precursor to product ion transitions of calcipotriol at m/z 411.1 → 393.5, and of lovastatin (internal standard) at m/z 403.2 → 101.2. The assay was linear in all matrices with LLOQs of 1, 0.5 and 40 ng/mL for skin homogenate, receptor medium and ointment samples respectively. In terms of the permeation profiles, it was found that calcipotriol permeated through all skins to only a limited extent over 20 h after application but was efficiently retained in all skins at a level at 20 h of between 40% (pig) and 60% (rat and mouse) of the applied dose. This indicates that calcipotriol ointment has the potential to provide sustained therapeutic benefit in the treatment of psoriasis with minimal systemic side effects. Copyright © 2013 John Wiley & Sons, Ltd.     

高职学报发展的新路径——集团化办刊

集团化办刊是借鉴职业教育集团的成功经验,将各高职学报以集团的形式组成规模较大的办刊联合体,充分发挥集团的规模优势。这必将有效增强其竞争力和影响力,实现其优势互补与资源共享,从根本上解决"小"而"弱"和优质稿源匮乏等顽疾,有力提升高职学报的办刊水平,并为高校学报今后的改革与健康发展探索新出路。     

Erosion of Thin Foils by Sputtering in Hollow Cathodes

A thin copper foil placed diagonally in a cylindrical copper hollow cathode undergoes fast erosion caused by cathode sputtering. Changes in the foil shape are related to current distribution along the hollow cathode axis. The experimental results aid in understanding the increase in spectral lines intensities emitted from conical bottom hollow cathode lamps.     

Strategic measures in optimal control problems for stochastic sequences

Controlled discrete–time stochastic processes axe studied using the convex–analytic approach. Some new properties of strategic measures spaces are established, particular Markov models are considered. The meaningful example is presented.     

Novel hybrids of Cu2+ ternary complexes of salicylidene-amino acid Schiff base with phenanthroline（or bipyridine） intercalated in Mg/Al-NO3-layered double hydroxide

Four Cu²⁺ complexes of salicylidene-amino acid Schiff base with 1,10-phenanthroline（Phen） or 2,2’- bipyridine（Bipy） were successfully intercalated in interlayer galleries of Mg/Al-NO₃-layered double hydroxide（LDH） by the swelling-restored method.The hybrids were characterized by elemental analysis,X-ray diffraction,FT-IR spectra,UV-vis DRS,TG-DTA and SEM observation.Good protection of the complexes by LDH in neutral and weak acidic solutions was revealed by UV spectra,cyclic voltammograms and luminescence spectra.     

IR-Spectral Study of Self-Association Effects of 2-Aminopyridine in Solution

A comparative IR-spectral study of solute-solute hydrogen bond formation in carbon tetrachloride and chloroform solutions of 2-amino-pyridine is reported. The presence of chain-like self-associates is confirmed in contrast to the solid state where the stabilization of the cyclic dimeric structure takes place. This conclusion is suggested on the basis of the NH₂ stretching region data obtained by changing the solute concentration as well as by comparing with the corresponding data about melted and solid state 2-aminopyridine and 3-aminopyridine samples.