Study the effect of Vitamin K on intracellular NAD level in yeast by fluorescence spectrum

The intracellular NAD level plays a pivotal role in numerous biological processes such as rhythm, senescence, cancer and death. The study of the intracellular NAD level has been one of the "hotspots" in biomedical research. We investigated the effect of Vitamin K on intracellular NAD level in yeast by fluorescence spectrum in this paper. Plasma membrane redox system of yeast was found to be greatly promoted by the addition of Vitamin K(3) or Vitamin K(1). Ferricyanide reduction catalyzed by Vitamin K was accompanied by the decrease in intracellular NADH concentration and the increase in intracellular NAD level of yeast cells.     

静电纺丝法制备定向排列的铁氧体纳米纤维

以聚乙烯吡咯烷酮(PVP)和金属硝酸盐为原料,采用改进的静电纺丝法制备了直径均匀、表面光滑、定向排列的Co0.8Zn0.2Fe2O4/PVP纳米纤维前驱体,经热处理后得到定向排列的铁氧体纳米纤维.对前驱体纤维的热分解过程及Co0.8Zn0.2Fe2O4(CZFO)的结构、物相及形貌进行了表征.结果表明,在空气中经550～950℃热处理3 h后均得到纯相、结晶良好的尖晶石型钴锌铁氧体;在2000 r/min转速下收集的复合纤维形貌最佳,直径约300 nm;经750℃热处理后纤维直径约为70 nm,室温下测得饱和磁化强度为66.1 A.m2/kg,矫顽力达到最大值6.6 A/m,表明钴锌尖晶石型铁氧体单畴临界尺寸约为44 nm.与CoFe2O4相比,CZFO的饱和磁化强度升高,矫顽力下降,并且CZFO的纤维与粉末的磁特性有明显的区别.     

手性配体2,5-二(4,5-蒎烯-2-吡啶)吡嗪及其铼配合物的合成与表征

本文报道了手性配体2,5-二(4,5-蒎烯-2-吡啶)吡嗪(L)及其铼配合物[Re(CO)3Cl(L)].DMF的合成与表征。X射线单晶衍射分析表明配体L晶体为单斜P21空间群,而配合物[Re(CO)3Cl(L)].DMF晶体为正交P212121空间群。配合物[Re(CO)3Cl(L)].DMF中铼原子与配体中的2个氮原子、3个羰基中的碳原子以及1个氯原子配位。CD谱和VCD谱测试表明,配体和配合物都表现出光学活性。受光激发时,配体和配合物分别在420和650 nm处发光。配体和配合物都具有二阶非线性光学性质,其二阶非线性光学效应分别为尿素的0.4和0.3倍。     

阻抑乙基橙褪色动力学光度法测定痕量铁(Ⅲ)

在H2SO4介质中,痕量铁(Ⅲ)对KBrO3氧化乙基橙褪色反应有很强的阻抑作用,利用光度法检测阻抑反应过程中乙基橙浓度的变化,建立了铁(Ⅲ)-溴酸钾-乙基橙体系阻抑动力学光度法测定痕量铁(Ⅲ)的方法。在选定条件下,方法的线性范围为0.006～0.32μg/mL,检出限(3s/k)为0.0031μg/mL。     

The Perturbed Problem on the Boussinesq System of Rayleigh-Bénard Convection

In this paper,the infinite Prandtl number limit of Rayleigh-B′enard convection is studied.For well prepared initial data,the convergence of solutions in L∞(0,t;H2(G)) is rigorously justified by analysis of asymptotic expansions.     

Spectrophotometric determination of procaine hydrochloride with hemoglobin as catalyst

A highly sensitive and simple spectrophotometric method for the determination of procaine hydrochloride based on its inhibitory effect on the hemoglobin-catalyzed reaction of H₂O₂ and acid chrome blue K(ACBK) was developed. The concentration of procaine hydrochloride is in linear relationship with the percentage inhibition (I%) of system under the optimal experimental conditions. The calibration graph is linear in the range from 1.50 × 10⁻⁷ to 4.15 × 10⁻⁶ M with the detection limit of 3.80 × 10⁻⁸ M. This method can be used for the determination of procaine hydrochloride in injection solution of procaine hydrochloride with satisfactory results. The article is published in the original. The article is published in the original.     

抗EGFR单克隆抗体表面电荷不均一性的分析条件优化

优化离子交换色谱法分析抗表皮生长因子受体(Epidermal growth factor receptor,EGFR)单克隆抗体表面电荷不均一性的条件。考察了离子交换色谱法分析抗EGFR单克隆抗体表面电荷不均一的条件,包括色谱柱、流动相pH、梯度及柱温。离子交换色谱法分析表面电荷不均一性的最佳条件:TSK-gelCM-STAT离子交换色谱柱、流动相pH6.0、合适的起始梯度及梯度陡度有利于电荷不均一性各组分的分离,柱温为40℃。合适的分析条件能够使单克隆抗体表面电荷不均一性各组分在离子交换色谱柱上得到最佳分离及获得较高灵敏度。