Investigation on the Inclusion Behavior of ApoCopC with Vitamin B6

In neutral phosphate buffer solution of pH 7.0, the interaction between apoCopC and Vitamin B₆ has been investigated in detail by means of fluorescence spectroscopy. According to the change of Vitamin B₆ fluorescence spectra and fluorescence polarization, we can conclude that a novel supramolecular system is generated. ApoCopC can form a 1:5 host-guest inclusion supramolecular complex with Vitamin B₆, and the formation constant has been calculated to be (2.24 ± 0.08) × 10⁴ M^? 1. It suggests the strong inclusion ability of apoCopC to the guest molecules. In addition, the mechanism of the apoCopC protein fluorescence quenching by Vitamin B₆ was also discussed. And based on the Stern-Volmer equation, the apparent quenching constant was estimated to be (2.75 ± 0.05) × 10⁴ M^? 1.     

Phenylboronic acid and dopamine as probe set for electrochemical detection of saccharides

A novel electrochemical approach for detection of saccharides via indicator displacement assay was presented. In this system, 2-fluorophenylboronic acid and dopamine (DA) were performed as probe set. The electrochemical properties of DA and the binding to 2-fluorophenylboronic acid in phosphate buffer at different pH values were investigated by cyclic voltammetry. After addition of fructose to the solution, a competition for the binding 2-fluorophenylboronic acid occurred that led to the release of the DA. The regenerate oxidation current of DA increased with increasing fructose concentration. Under optimized experimental conditions, the peak current was linearly related to fructose concentration in the range of 0.3-5.0 mmol/L with a detection limit of 0.1 mmol/L. In addition, the interaction between 2-fluorophenylboronic acid and other cis-diol compounds such as glucose, galactose and mannose was investigated.     

原位脱羧制备的配合物(HP2W18O62)(C6H6NO2)5·2H2O:结构、光谱及电化学性能

采用水热法将钨酸钠和浓磷酸与有机配体吡啶-2,6-二羧酸通过原位脱羧制得配合物(HP2W18O62)(C6H6NO2)5.2H2O(1),并用红外光谱、紫外光谱、循环伏安(CV)和X射线单晶衍射等方法进行了表征。分子中的2-吡啶甲酸来源于吡啶-2,6-二羧酸的脱羧反应。化合物1属于单斜晶系,空间群P21/n,晶胞参数分别为:a=1.553 3(2)nm,b=2.006 3(3)nm,c=2.759 9(4)nm,β=103.981(2)°,Z=4,F(000)=8 816。分子间氢键和2-吡啶甲酸与杂多化合物间的弱相互作用使该化合物具有3D超分子结构。CV结果表明,化合物1有四步氧化还原反应。     

用EXAFS方法研究玻璃中混合配位态的比例及结构

在某些氧化物玻璃中,阳离子可能处于不同的配位状态,研究其原子近邻结构及配位态变化规律是人们感兴趣的问题之一。一般的EXAFS分析方法对此类问题处理会出现错误。本文对混合配位态问题所用的EXAFS分析方法,既可研究不同配位态原子的近邻结构,又可得到不同配位态的含量.以Li₂O-ZnO-GeO₂系统玻璃为例,研究了Ge原子近邻四、六两种氧配位的比例随玻璃组成变化的情况,并给出了近邻结构参数。     

ICP-AES测定电镀高纯铜中微量磷

用浓HNO3溶解高纯铜试样，电感耦合等离子体发射光谱(ICP-AES)测定其中微量磷，并对试样处理、测试方法、提高灵敏度等条件进行了优化实验。结果表明，方法回收率为99．07％-102．0％，RSD(n＝6)为0．22％-0．25％。     

盐酸氯丙嗪对八肋游仆虫中心蛋白C端功能的抑制

通过荧光光谱分析、等温滴定量热(ITC)、圆二色谱(CD)、电泳等技术研究了盐酸氯丙嗪(CPZ)和八肋游仆虫中心蛋白C端(apoC-EoCen)的结合以及CPZ对蛋白功能的影响。结果表明,在室温下10 mmol·L^-1 Hepes溶液(pH=7.4)中,CPZ与apoC-EoCen以物质的量之比为1∶1结合,条件结合常数约为104L·mol^-1。CPZ的结合导致蛋白质的二级结构发生改变,α螺旋含量减小;对金属离子诱导中心蛋白的聚集产生了抑制作用,Tb3+敏化荧光强度也降低;阻碍了中心蛋白与着色性病干皮病C组蛋白(XPC)的结合;且影响了apoC-EoCen类核酸酶活性,导致蛋白对pBR322 DNA的切割能力下降;抑制了蛋白质的磷酸化。综合实验结果表明盐酸氯丙嗪是中心蛋白的生物功能阻断剂,对中心蛋白的功能具有良好的调控作用。     

Metal ions-induced conformational change of P23 by using TNS as fluorescence probe

In 10 mM N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid (Hepes), pH 7.4, 25 degrees C, the conformational change of the truncated form of ciliate Euplotes Octocarinatus centrin (P23) induced by metal ions were investigated using 2-p-toluidinylnaphthalene-6-sulfonate (TNS) as a probe. The results show that upon metal ions binding, P23 undergo a conformational change and the contributions to the conformational change from the two EF-hands are different, and Tb3+ has more larger influence than Ca2+ with the same concentration metal ions, which provide possible the evidence that the different EF-hands play distinct biological functions. Meanwhile, the conditional binding constants of TNS and Ca2-loaded or Tb2-loaded P23 were obtained, K (Ca2-P23+TNS)=(7.49+/-0.88)x10(5) mol-1 L, K (Tb2-P23+TNS)=(8.24+/-0.49)x10(5) mol-1 L.     

带有n+深阱的三阱CMOS工艺中寄生NPN双极效应及其对电荷共享的影响

基于三维TCAD器件模拟, 研究了带有 n⁺深阱的90 nm三阱CMOS器件在重离子辐照下产生的电荷共享效应. 研究结果表明在重离子辐照时, n⁺深阱会导致寄生的NPN双极型晶体管触发, 显著增强NMOS间的电荷共享, 其放大因子达到双阱工艺中寄生PNP晶体管放大因子的2---4倍. 进而分别研究了n阱接触和p 阱接触对寄生NPN双极放大的影响, 结果表明增大p阱接触的面积和减小 n 阱接触的距离将抑制NPN晶体管的放大作用, 而增大n 阱接触的面积将增强NPN的放大作用.     

Single-photon scattering by a Λ-type three-level in a cavity coupling to one-dimensional waveguide

The scattering of single-photon by a Λ-type three-level embedded in a cavity which is coupled to a one-dimensional waveguide is investigated theoretically by full quantum-mechanical approach. The single-photon transmission amplitude and reflection amplitude are obtained via real-space approach, respectively. It reveals that single-photon can be transmitted or reflected by controlling classic driving field tuning off or on. The effects of dissipations of the cavity and of the atom on the photon transport properties are also discussed.     

番茄红素的紫外可见光谱和荧光光谱分析

研究了番茄红素在不同溶剂中的紫外可见光谱图,对结果进行分析后发现番茄红素在正己烷、石油醚、丙酮、乙酸乙酯具有较低折光率的溶剂中的特征吸收带波长非常接近,但在较高折光率的溶剂苯、二硫化碳中的特征吸收带与以丙酮作为溶剂相比有不同程度的红移。番茄红素溶于丙酮与水的混合溶剂,当丙酮与水的体积比达到3∶2时,吸收光谱在紫外区出现一新的吸收峰,在可见区吸收光谱的精细结构消失。用荧光光度计采集不同溶液的番茄红素的荧光光谱,番茄红素的荧光峰位于580—590nm,在极性溶剂中荧光发射增强。