Roles of Phe58 residue in stabilizing structure of cytochrome b<Subscript>5</Subscript>

To understand effect of π-stacking interactions between the side chain of aromatic amino acids and the porphyrin ring on structures and properties in cytochrome b₅ (cyt b₅), the Phe58 residue was mutated to tyrosine and tryptophan, respectively by site-directed mutagenesis. The denaturation of cyt b₅ F58W and F58Y toward guanidine hydrochloride was examined by UV-visible and fluorescence spectroscopy. The kinetics of heme transfer reactions between apo-myoglobin and the mutants were studied. The results indicated that the mutation of F58 residue for Y58 or W58 reduced the interaction between of peptide and the heme group, resulting in decrease of the T _m and C _m values of the proteins, increase of the heme transfer reaction rate, and shifts of the redox potential.     

藏红T与核酸作用的荧光特性研究

低离子强度和生理酸度下,藏红Ｔ（ＳＴ）与核酸的作用随ＳＴ与核酸的摩尔比（Ｒ）变化具有３种荧光特性,表现出３种结合机理．当Ｒ＞０３３,ＳＴ的荧光为核酸线性猝灭,最大激发波长发生紫移,但发射波长不变,是ＳＴ在核酸分子表面进行长距组装;Ｒ在０３３～０１３范围内,ＳＴ的荧光虽为核酸猝灭,但没有线性关系,表现为ＳＴ在核酸分子表面的组装与嵌入核酸碱基对结合处于微弱的平衡状态;当Ｒ＜０１３,ＤＮＡ体系产生新荧光,荧光激发峰红移,而发射波长仍保持不变,对应于ＳＴ嵌入核酸的双联碱基对之间,而ＲＮＡ体系却没有新的荧光产生．     

(k+1)-连通无K_(1,r)-图是Hamilton-连通的两个充分条件

一个图若不含与Ｋ１,ｒ（ｒ３）同构的导出子图,则称它为无Ｋ１,ｒ－图．本文将运用Ｔ－插点方法,通过对图的独立集的邻域交的研究,给出（ｋ＋１）－连通无Ｋ１,ｒ－图（ｒ４）是Ｈａｍｉｌｔｏｎ－连通的两个充分条件．     

4,5—亚乙二硫基—1,3—二硫杂环戊烯—2—酮衍生物的合成

以二（１,３－二硫杂环戊烯－２－硫酮－４,５－二硫）合锌酸四乙基铵盐（Ｉ）为原料,合成四种未见文献报道的４,５－亚乙二硫基－１,３－二硫杂环戊烯－２－硫酮及酮ＩＶａ,ＩＶｂ,Ｖａ,Ｖｂ,其中由路线Ａ和Ｂ分别制得了Ｖａ;对ＩＶｃ和由路线Ａ制备Ｖｂ失败的原因进行了讨论。     

Mechanisms of peroxynitrite-induced [Ca2+]i increase in single neuronal cell

The mechanism of peroxynitrite (ONOO⁻)-induced [ca²⁺]_i increase in single MN9D cell (Dopaminergic neuroblastoma cell line) was studied by using Fura-2 microfluorometric technique. The results show that ONOO⁻ caused a rapid increase of [Ca²⁺]_i when ONOO₋ was puffed to the cell. Removing Ca²⁺ from the bath or using calcium channel antagonist (CdCl₂, Nifedipine) greatly inhibited the [Ca²⁺]_i increase induced by ONOO⁻¹, suggesting that the opening of L-Ca²⁺ channel makes a great contribution to the [Ca²⁺]_i increase. The effect of sulfhydryl reductive agent (DTT) on ONOO⁻-induced [Ca²⁺]_i increase suggests that ONOO⁻-activating L-Ca²⁺ channel is partly related to its oxidative speciality.     

鲁棒控制器-观测器在转台控制系统设计与仿真中的应用

采用鲁棒降阶观测器控制器联合设计的方法针对ＨＩＴ３Ｔ２型飞行仿真转台中框控制系统的不确定线性模型设计了中框加速度的鲁棒降维观测器控制器．基于此,对中框控制系统设计了校正网络．仿真结果表明,系统在标称工作点达到了所希望的性能指标,同时具有一定的鲁棒稳定性和鲁棒性能．     

线切割机床加工T10A材料时脉冲宽度对切割速度的影响

通过一系列试验,确定了对于不同厚度的T10A材料在采用相应的脉宽与脉间比进行线切割加工时最高切割速度所对应的最佳脉宽值．     

Cr(Ⅵ)氧化5-溴水杨基荧光酮光度法测定微量Cr

在硫酸介质中,Ｃｒ（Ⅵ）将５－溴水杨基荧光酮（５－ＢＳＡＦ）氧化成最大吸收峰为４９４ｎｍ的有色产物,其表观摩尔吸光系数为３．６７×１０４Ｌ／（ｍｏｌ·ｃｍ）,Ｃｒ（Ⅵ）量在０～１５ｍｇ／２５Ｌ范围内服从比耳定律。用此法测定了电镀废液中微量Ｃｒ,回收率为９８．５％～１０３％,相对标准偏差为２．６％     

Tapia 半内积与 Banach 空间的几何性质

利用Ｔａｐｉａ半内积（ｘ,ｙ）Ｔ＝ｌｉｍｔ→０＋［（ｘ＋ｔｙ２－ｘ２）／（２ｔ）］,ｘ,ｙ∈Ｘ,研究了Ｂａｎａｃｈ空间Ｘ的自反和逼近性质,并在光滑的Ｂａｎａｃｈ空间Ｘ上利用由Ｔａｐｉａ半内积定义的一类连续线性泛函Ｔ（Ｘ）＝｛ｆｘ∈Ｘ＊｜〈ｆｘ,ｙ〉＝（ｘ,ｙ）Ｔ;ｘ,ｙ∈Ｘ｝研究了Ｂａｎａｃｈ空间的严格凸、一致凸以及具有性质（Ｈ）的特征．     

5─(4''''─磺酸基苯偶氮)罗丹宁的合成及与钯(Ⅱ)显色反应的研究

本文报导了新试剂5─（4＇─磺酸基苯偶氮）罗丹宁的合成及其与把（Ⅱ）的显色反应．在非离子表面活性剂TritonX-100的存在下,于pH58的磷酸二氢钾─氢氧化钠缓冲溶液中,试剂可与钯（Ⅱ）生成2：1的橙色络合物,其最大吸收波长位于460nm处,摩尔吸光系数ε为8.3×104L.mol-1.cm-1,钯量在0～10μg/25ml范围内符合比尔定律,方法用于测定催化剂中钯的含量,结果满意．