Improved expression by cytomegalovirus promoter/enhancer and behavior of vascular endothelial growth factor gene after myocardial injection of naked DNA

Direct injection of the vascular endothelial growth factor (VEGF) gene plasmid DNA into the myocardium was shown to induce development of new blood vessels to increase the circulation in the heart of patients with coronary artery diseases. However, such angiogenic gene therapy (via naked DNA) was limited by low level of gene expression. Furthermore, the temporal and spatial characteristics of VEGF gene transfer in the heart are not known. In this study, we demonstrated that a plasmid vector, containing the human cytomegalovirus immediate early (HCMV IE) promoter and enhancer, induces greater expression of gene in the rat heart monitored by gene fused to the chloramphenicol acetyl transferase (CAT) reporter, than four different viral and cellular promoters. Interestingly, expression of VEGF121 protein showed an earlier peak, a shorter duration, and a wider distribution than that of CAT only. Therefore, a plasmid vector with an HCMV IE promoter/enhancer provides clear advantages over other previously developed plasmids. Furthermore, expression profile of VEGF121 gene may provide useful information in the design of angiogenic gene therapy in the heart.     

Separation and determination of ephedrine alkaloids and tetramethylpyrazine in Ephedra sinica Stapf by gas chromatography-mass spectrometry

A simple, sensitive, and reliable method using gas chromatography (GC)-mass spectrometry (MS) is developed for the simultaneous determination of ephedrine alkaloids and 2,3,5,6-tetramethylpyrazine (TMP) in Ephedra sinica Stapf. The sample is extracted with ethyl ether and submitted to GC-MS for identification and quantitation without derivatization. The column used for GC is an HP-5 (30.0 m x 250 microm x 0.25 microm, 5% phenyl methyl siloxane), and the carrier gas is helium. The detection limits for ephedrine, pseudoephedrine, and TMP are 0.4 ng 0.7 ng, and 0.02 ng (signal-to-noise ratio of 3), respectively. The reproducibility of the total procedure is proved to be acceptable (RSD < 2%), and the recoveries are above 93%.     

基于壳聚糖膜固定双酶的胆碱传感器的研究

提出了一种基于壳聚糖膜固定辣根过氧化物酶 胆碱氧化酶的胆碱传感器的制备方法。该传感器以电聚合于玻碳电极的硫堇作为电子传递介体,在pH6. 8,外加电压-0. 2V(vs.SCE)条件下,其峰电流与浓度范围 5. 0×10-5 ~3. 0×10-3 mol/L的胆碱呈良好的线性响应;检出限为 1. 0×10-5 mol/L。传感器有良好的选择性和稳定性,使用一月后,仍能保持其初始活性的 80%。     

Luminescence 3D-ordered porous materials composed of CdSe and CdTe nanocrystals

The luminescence porous materials of CdTe or CdSe nanocrystals (NCs) were prepared by filling the corresponding NCs into the voids of colloidal crystal by co-deposition of polymer beads and NCs. After removing the beads with tetrahydrofuran (THF), the 3D-ordered porous materials of CdTe (or CdSe) NCs were obtained. The wavelength of maximum photoluminescence of the NCs porous material shows obvious red shift compared with their aqueous dispersion. Under the excitation of high-energy electron the porous materials of CdTe and CdSe NCs will emit photons that can be collected to form a cathode luminescence (CL) image.     

ToF-SIMS analysis of surface-anchored organometallic clusters

ToF-SIMS analysis of the organometallic cluster Os₃(μ-H)(CO)₁₀(μ-SCH₂CH₂SH) chemically attached onto a silver or gold surface, and of the cluster fragment Os₃(μ-H)(CO)₁₀(μ-OSi) on a silica surface, allows for identification of the surface organometallic species, and also gives information on its reactivity.     

Synthesis of some dibenzodiazepinone derivatives as potent and m2-selective antimuscarinic compounds

Two series of 5-[[4-[4-(dialkylamino)butyl]-l-cyclohexyl]acetyl], and 5-[(dialkylamino)acyl]-10,11-dihydro-5H- dibenzo[b,e][1,4]diazepin-11-ones were synthesized as potential m2-selective ligands 1,2. Their affinity and selectivity for the muscarinic cholinergic receptor m-AChR subtypes were determined. Replacing a nitrogen with CH in the piperidine ring of 5-[[4-[4-(dialkylamino)butyl]-l-piperidinyl]acetyl]-10,11-dihydro-5H-dibenzo-[b,e][1,4]diazepin-11-ones 3 significantly altered the affinity and selectivity to the muscarinic receptor subtypes.     

停止-流动分光光度法研究铕(II)与二甲酚橙快速电子转移反应动力学

用停止-流动分光光度法研究了Eu~(2+)与二甲酚橙(XO)间快速电子转移反应的动力学规律。求得了速控步骤的动力学参数。如反应级数(n=2)、几个不同温度下的速率常数(k_(278 K)=5.7×10~8 L·mol~-·s~(-1), k_(s38 K)=1.01×10~9 L·mol~(-1)·s~(-1))、活化能(E=7.6×10~3 J·mol~(-1)), 以及指前因子(A=1.5×10~(10) L·mol~(-1)·s~(-1)), 并判断出其为溶液中扩散控制型反应。根据实验现象与测试结果, 提出了Eu~(2+)与XO的反应分别在Eu~(2+)相对过量和在XO过量时的反应机理, 并判断了各反应步骤速率常数之间的相对关系。     

固液相变的分子动力学研究Ⅰ─—(KI)_(108)离子簇的熔化和凝固(英)

通过分子动力学模拟，考查并分析了（KI）108离子簇的结构、能量和相变的动力学行为．在加热和冷却过程中，离子簇再现了熔化和凝固现象，而且熔化起始于立方体的其一顶点，熔化的离子簇不是球形的，说明了离子簇的非湿特征．根据结晶的成核速率，讨论了电子衍射实验中观察KI凝固的可能性     

Study on glucose oxidase fermentation coupled with membrane dialysis

The repression of glucose oxidase (GOD) biosynthesis by catabolites during fermentation can be alleviated through membrane dialysis fermentation (MDF). The results show that the volumetric enzyme productivity of MDF was two times higher than that of the control (fermentation without dialysis), and its total enzyme activity was increased by 30–50%. The operation conditions of MDF, such as pore size of the membrane, initiating time for membrane dialysis, and volume of dialysate used, were optimized. The content of amino acids and organic acids in the fermentation broth and the dialysate in the reservoir were assessed by amino acid analyzer and ionic chromatography, respectively. The relationship among the contents of pyruvic acid, gluconic acid, and enzyme activity during fermentation was analyzed quantitatively. Furthermore, the effect of membrane dialysis technology applied to the low-yield strain was found to be more effective than that applied to the high-yield strain.     

硒化合物对不饱和脂肪酸过氧自由基的作用

本文用电子自旋共振谱技术研究了硒代二乙酸和硒代二丙酸对不饱和脂肪酸过氧自由基的作用。结果表明,硒化合物清除不饱和度为2和2以上的脂肪酸的过氧自由基,但促进仅含一个双键的不饱和脂肪酸的过氧自由基的生成。