N,N-diethylaniline as hydrogen donor for determination of hydrogen peroxide catalyzed by metalloporphyrins as enzyme mimetic of peroxidase

Various metalloporphyrins have been used as a catalyst instead of the peroxidase for the determination of hydrogen peroxide by formation of a dye from N,N-diethylaniline (DBA) and 4-aminoantipyrine. The difference of relative catalytic activity was investigated between enzyme and enzyme mimetics. FeT(4-TAP)P [5, 10, 15, 20-tetrakis (4-trimethyl-ammoniumphenyl)-21H, 23H-porphine] was shown as the best enzyme mimetic for horseradish peroxidase (HRP) among metalloporphyrins tested. 0 to 7.0 × 10^–5 mol/L hydrogen peroxide was determined with good accuracy and reproducibility, and giving recovery of 99.7–100.7%. DEA was certified as a sensitive color reagent in enzyme mimetic assay of hydrogen peroxide, with the apparent molar absorptivity for hydrogen peroxide was 1.37 × 10⁴ L/mol·cm.     

Studies of an inclusion complex of a redox-active barbiturate with β-cyclodextrin

The effects of β-cyclodextrin (β-CD) on the spectral properties and electrochemical behaviour of barbitone sodium were studied using electrochemical and optical techniques. The apparent changes in the UV-visible absorption spectrum and fluorescence quenching of the barbiturate upon addition of β-CD afford clear evidence of the inclusion complex formation of β-CD in aqueous solutions. The redox acitivity of barbitone sodium in both the absence and presence of β-CD was assessed by an electrochemical method in 0.05 M potassium nitrate-nitric acid (pH 1.8) solution. While the complexation reaction remains is equilibrium, the apparent formation constant of the inclusion complex could be obtained by either spectral or electrochemical methods. Quantitative evaluation of the data gave 326 l mol⁻¹ under equilibrium conditions at 20°C. Possible conclusions are discussed on the basis of environmental changes around the barbiturate molecules on inclusion.     

Synthesis of Novel Heteroannular Disubstituted Cyclopalladated Ferrocenylimine

Cyclopalladated compounds derived from N-donor ligands have attracted great interest in the last decade due to their novel and outstanding applications in the fields of organic synthesis, catalysis and photochemistry.[1] But among all cyclopalladated ferrocenylimine derivatives reported so far, the palladium was bound to the substituted Cp ring, resulting in a five-membered metallocycle.     

Experimental Study of Single and Double Electron Detachment Cross Sections for Cl^- in Collision with He

Single-electron detachment （SED） and double-electron detachment （DED） for chlorine negative ions in collision with helium are investigated in the energy region of 5-30 keV （SED） and 5-19 ke V （DED） by growth rate method, respectively. Experimental data from this work are compared with the previous reported data, and a general discussion is given.     

高分子溶液特性粘度测定的新方法

提出了一个新的一点法测定高分子溶液的特性粘度的经验公式, 并根据文献的一些数据将该公式和常用的程镕时公式进行了比较研究. 结果表明, 该公式具有比程氏公式更高的准确性和广谱性, 还有简单易于操作的优点.     

碳包覆碳酸钴锂离子电池负极材料的制备及电化学性能

以葡萄糖作为碳源,通过简单的水热反应获得菱形碳包覆碳酸钴(CoCO₃/C)复合材料,并研究了其作为锂离子电池负极材料的电化学性能.晶型和表面形貌通过X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)进行表征,用热重-差热分析法(TG-DTA)来测试CoCO₃/C材料中碳的含量,用拉曼光谱分析无定型碳的存在. Barrett-Joyner-Halenda (BJH)则用来分析材料的孔径分布情况.实验表明,碳包覆不仅在CoCO₃颗粒表面包覆了一层无定性碳,使得CoCO₃材料在充放电过程中保持结构的稳定性,也形成了一些大约30 nm左右的介孔,这种孔的存在有助于电解液中离子的传输,从而提高材料的电化学性能.电极材料在0.90C(1.00C = 450 mAh•g^-1)倍率下进行循环测试, 500次后的容量仍保持在539 mAh•g^-1,显示出了较好的循环性能.当增加到3.00C倍率时CoCO₃/C容量为130 mAh•g^-1,再恢复到0.15C倍率时容量依然能够达到770 mAh•g^-1,表现出了CoCO₃/C具有良好的稳定性.     

一种基于DPA识别基团的可视化检测锌离子的荧光增强型探针

以N,N-二(2-吡啶甲基)胺(DPA)为识别基团,设计合成了一种用于检测Zn2+的荧光增强型探针WN,在CH3CH2OH/TrisHCl(1∶9,V/V,pH=7.4)缓冲溶液中研究了它对Zn2+的识别特性。实验结果表明,WN对Zn2+有较高的选择性和灵敏度,它们之间的结合比为1∶1,对Zn2+的检出限为1.14×10-8 mol·L-1。WN能够快速地可视化检测Zn2+,在HeLa活细胞中对Zn2+的荧光显微成像表明WN可应用于生物体的检测。     

尺寸排阻色谱柱上尿素梯度复性全长人PPAR-γ

建立尺寸排阻色谱柱上尿素梯度复性全长人PPAR-γ重组蛋白的方法。利用尺寸排阻色谱柱上尿素梯度除去变性剂直接复性变性蛋白。添加尿素和精氨酸抑制聚集以提高复性产率,加入Zn2+促进变性蛋白形成正确折叠。复性后,重组蛋白的尺寸排阻色谱保留体积增大;紫外光谱最大吸收波长从234.0nm变为280.8nm;基质辅助激光解析-电离飞行时间质谱分析重组蛋白的完整性,测得分子量与理论值一致;放射配体受体结合饱和实验测得解离常数(Kd)为89±4nmol/L;复性产率为52.7%。结果表明本文所建立的方法能成功用于复性变性全长人PPAR-γ,获得可用于结构和功能研究的具有生物学活性的全长人PPAR-γ蛋白。     

Swerilactones E-G, three unusual lactones from Swertia mileensis

Swerilactones E (1), F (2), and G (3), three unusual lactones with a phenyl group, were isolated from the traditional Chinese herb of Swertia mileensis. Their structures were determined based on extensive spectroscopic analysis and X-ray single crystal crystallography. Our anti-HBV assay on the Hep G 2.2.15 cell line in vitro showed that compounds 1 and 2 exhibited significant inhibitory activities against the secretion of HBsAg with IC₅₀ of 0.22 and 0.70 mM and HBeAg with IC₅₀ of 0.52 and >6.78 mM, respectively.