S Phase Cell Percentage Normalized BrdU Incorporation Rate, a New Parameter for Determining S Arrest

In this study, a new parameter, S phase cell percentage （S fraction） normalized BrdU （SFN-BrdU） incorporation rate, was introduced to detect $ arrest. The results showed a positive linear correlation between the BrdU incorporation rate and the S fraction in unperturbed 16HBE cells. Theoretical analysis indicated that only S arrest could result in a decrease in the SFN-BrdU incorporation rate. Additionally, the decrease in SFN-BrdU incorporation rate and the activation of DNA damage checkpoints further demonstrated that S arrest was induced by diethyl sulfate treatment of 16HBE cells. In conclusion, $FN-BrdU incorporation rate can be used to detecting S arrest.

正相高效液相色谱法测定有机金属抗癌原料药二氯二茂钛的含量

建立了正相高效液相色谱测定有机金属抗癌原料药二氯二茂钛含量的方法。色谱条件为:以Lichrosorb-CN柱(4mm×250mm,5μm)为分离柱,正己烷-二氯甲烷(体积比为50∶50)为流动相,流速为1mL/min,紫外检测波长为254nm,柱温为25℃。以ω-溴代苯乙酮为内标测定二氯二茂钛原料药的含量。样品中待测组分与内标物分离良好,线性范围为2.5-50mg/L,日内和日间测定的精密度(以相对标准偏差(RSD)计)均小于1.0%。方法简便、快速,结果准确,专属性强,灵敏度高,可用于测定有机金属类抗癌原料药二氯二茂钛的含量。

High performance liquid chromatographic separation of eight drugs collected in Chinese Pharmacopoeia 2010 on amylose ramification chiral stationary phase

The enantiomers separation of ei ght pharmaceutical racemates collected in Chinese Pharmacopoeia 2010(Ch.P2010),including nitrendipine,felodipine,omeprazole,praziquantel,sulpiride,clenbuterol hydrochloride,verapamil hydrochloride and chlorphenamine maleate,was performed on chiral stationary phase of amylose ramification by high performance liquid chromatography(HPLC)on Chiralpak AD-H column and Chiralpak AS-H column with the mobile phase consisted of isopropanol and n-hexane.The detection wavelength and the flow rate were set at 254 nm and 0.7 mL/min,respectively.The effects of proportion of organic additives,alcohol displacer and temperature on the separation were investigated.The results indicated that eight chiral drugs were separated on chiral stationary phase of amylase ramification in normal phase chroma tographic system.The chromatographic retention and resolution of enantiomers were adjusted by factors,including the changes of the concentration of alcohol displacer in mobile phase,organic alkaline modifier and column temperature.It was shown that the resolution was improved with reducing concentration of alcohol displacer.When the concentration of organic alkaline modifier was 0.2%,the resolution and the peak shape were fairly good.Most racemates mentioned above had the best resolution at column temperature of 25℃.The best temperature should be kept unchanged in the process of separation so as to obtain stable separation results.

The correlation between serum uric acid level and early- phase insulin secretion in subjects with normal glucose regulation

Objective To investigate the correlation between serum uric acid(SUA)level and early-phase insulin secretion in subjects with normal glucose regulation(NGR).Methods Totally 367 community NGR residents confirmed by a 75g oral glucose tolerance test were enrolled.

Thermodynamics under the impact of thermal fluctuations and quasi-normal modes of Euler-Heisenberg AdS BH in the framework of NLED

We study the impact of thermal fluctuations on the thermodynamics,quasi-normal modes,and phase transitions of an anti-de Sitter Euler-Heisenberg black hole(BH)with a nonlinear electrodynamic field.An anti-de Sitter Euler-Heisenberg BH with a nonlinear electrodynamic field is composed of four parameters:the mass,electric charge,cosmological constant,and Euler-Heisenberg parameter.We calculate thermodynamic variables such as Hawking temperature,entropy,volume,and specific heat,which comply with the first law of thermodynamics.First,we use this BH to determine the thermodynamics and thermal fluctuations with the Euler-Heisenberg parameter to distinguish their effect on uncorrected and corrected thermodynamical quantities.We derive the expression for corrected entropy to study the impact of thermal fluctuation with simple logarithmic corrections on unmodified thermodynamical potentials,including Helmholtz energy,pressure,Gibbs free energy,and enthalpy.The Euler-Heisenberg parameter improves BH stability at large radii.Second,we analyze the local stability of the proposed BH,and the phase shifts of the BH are also investigated using temperature and specific heat.When there is a decrease in charge and an increase in r_(+)andα,the temperature shifts from an unstable region to a stable one.Similarly,increases in local stability are observed with each of these parameters.Third,we use null geodesics to deal with the effects of nonlinear electrodynamics on the quasi-normal modes of the Euler-Heisenberg anti-de Sitter BH.The null geodesics provide the angular velocity and Lyapunov exponent of the photon sphere,which are the same as the real and imaginary parts of the quasi-normal modes in the eikonal limit.

Recent progress in polar metabolite quantification in plants using liquid chromatography-mass spectrometry

Metabolite analysis or metabolomics is an important component of systems biology in the post-genomic era.Although separate liquid chromatography（LC） methods for quantification of the major classes of polar metabolites of plants have been available for decades,a single method that enables simultaneous determination of hundreds of polar metabolites is possible only with gas chromatography-mass spectrometry（GC-MS） techniques.The rapid expansion of new LC stationary phases in the market and the ready access of mass spectrometry in many laboratories provides an excellent opportunity for developing LC-MS based methods for multitarget quantification of polar metabolites.Although various LC-MS methods have been developed over the last 10 years with the aim to quantify one or more classes of polar compounds in different matrices,currently there is no consensus LC-MS method that is widely used in plant metabolomics studies.The most promising methods applicable to plant metabolite analysis will be reviewed in this paper and the major problems encountered highlighted.The aim of this review is to provide plant scientists,with limited to moderate experience in analytical chemistry,with up-to-date and simplified information regarding the current status of polar metabolite analysis using LC-MS techniques.