ON THE NATURE OF THE NUCLEOPHILE IN THE MIXTURE OF PHOSPHITES AND AMINES

Abstract

It is now commonly accepted that in the presence of strong bases (like metal alcoholates) an equilibrium between phosphite and phosphonate forms of dialkyl phosphites exists and that the phosphite form is highly reactive in the reaction with carbonyl compounds. There is a controversy on the structure of the active form of the phosphite when the addition is catalyzed by amines. We have found that aliphatic amines and dialkyl phoshites form a complex which is a reactive species. Its stoichiometry depends on the nature of the solvent.     

THE NATURE OF THE HOMONUCLEAR BOND IN ORGANIC AND INORGANIC DICHALCOGENIDES

Abstract

The electronic structures of a number of disulfide R₂S₂, and peroxide, R₂O₂, compounds are theoretically investigated or reinvestigated, and the results are compared and contrasted with each other as well as with experimental data. The results show that the enormous bond length variations in these compounds cannot be explained on the basis of the simple electronegativity difference model, but rather one must take into consideration terminal group atomic orbital contributions to the predominately homonuclear bonding molecular orbitals. The qualitative aspects of the bonding parameters of a large number of disulfide and peroxide compounds are explained.     

铜(Ⅱ)及其配合物催化胆红素氧化动力学的研究

本文用电化学，吸收光谱等方法对Ｃｕ（２＋）及其配合物与胆红素在碱性（ｐＨ１０）条件下的作用规律进行了研究．发现Ｃｕ（２＋）及其配合物对胆红素的氧化的催化作用依配合物的稳定性和配体齿数不同而异．在胆红素的氧化过程中，真正起氧化作用的是溶解氧．     

RECOGNITION SEQUENCE SPECIFICITY OF SIGNAL PEPTIDASE I AND THE ROLE OF SIGNAL PEPTIDE IN SECRETION OF PROTEIN IN Bacillus subtilis

By recombinant DNA technology, the N-terminal of the β-protein encoding region of plasmid pUBHO is fused with the structure gene of α-amylase from Bacillus licheniformis. This gene fusion is called βAmy. It is able to transcribe and translate in phase. Protein fusion can be secreted into the medium mediated by β-signal peptide. The efficiency of secretion is about 10% of the synthesized pre-α-amylase. By comparing the secretion capacities and analysing the restriction sites on β-Amy genes and the molecular weights of the mature α-amylase secreted by B. subtilis harbouring different plasmids, it is indicated in vivo that the recognition and cleavage sequence for signal peptidase I of B. subtilis is Ala-Ala-Ala Ala. The results also indicate that the secretion of the α-amylase in B. subtilis is in accordance with the post-translational transportation mode.     

胆红素有序分子膜的行为研究

研究了不同亚相表面胆红素(BR)单分子膜和LB膜的性质,讨论了胆红素分子在有序分子膜中的堆积密度、分子伸展和金属离子配位。在气-水界面,BR与金属离子的配位导致BR单分子截面积、崩溃压和可见紫外光谱的变化。原子力显微镜表明BR-Cu单分子膜的厚渡为1.23 nm。     

NATURE OF THE A AND THE F MATRIX IN THE CALCULATION OF FORCE CONSTANTS OF MOLECULAR VIBRATION

In this paper,calculations of force constants of molecular vibrations are carried out by using Wilson GF matrix method.In the determination of force constants from frequencies and factorization of Gmatrix,an ordering relationship of A matrix(may be n dimensional) relative to L matrix was found according to the ordering of symmetry coordinates.With the help of inverse unitary transformation,a general method to calculate Ft from constants Fs was established.The additivity of Fr depending on the symmetry block was determined to be true.All the force constants in non-planar and planar of urea,thiourea and sclenouroa molecules were calculated by using the general va-leine force field.The calculated values of frequencies were com-pairec with other data given in the literature,and it was shown that the present calculation is in good agreement with the experimental     

电化学聚对苯膜的现场ESR及其性能研究

本文用现场电化学-ESR联合测试的技术, 对电化学聚对萃膜在浓H_2SO_4中的性质进行了研究, 结果表明: 聚对苯膜具有高的电导率和相对低的自旋磁化率, 极化子与偶极化子为主要导电者, 并在一定的电位下相互转化, 自旋粒子有很大的离域性。膜中链与链之间可能存在部分的氧桥结构, 而引起体系结构的某些变化, 使聚对苯膜的电导提高以及掺杂容易进行。掺杂量受电位控制, 浓H_2SO_4中的HSO_4~-嵌入/脱嵌的电化学可逆性很好, 最大掺杂量可相当于每5个苯环单元氧化出一个正电荷, 可望将电化学聚对苯用作稳定的二次电池电极材料。     

WAVELENGTH DEPENDENCE OF QUANTUM YIELDS AND PRODUCT DISTRIBUTION IN THE ANAEROBIC PHOTOCHEMISTRY OF BILIRUBIN DIMETHYL ESTER

Abstract— ( Z,Z )-Bilirubin dimethyl ester exists in two or more forms in solution, and photorearranges to the ( E,Z )- and ( Z,E )-isomers. Deaerated solutions of bilirubin dimethyl ester in 2-methyltetrahydrofuran and chloroform/ethanol were irradiated with light of 10nm bandwidth in the range 380–470 nm at room temperature. Absorption difference spectroscopy showed that the solution forms of bilirubin dimethyl ester differ in their photoreactivity, and that the quantum yields of their disappearance and the distribution of the photorearrangement isomers are wavelength dependent.     

羧甲基壳聚糖对胆红素的吸附性能研究

合成了不同取代度的羧甲基壳聚糖(CM-CTS)作为吸附剂，研究了不同条件对CM-CTS吸附胆红素性能的影响．结果表明：在实验条件下，随着羧甲基取代度的增加和体系温度的升高．最大吸附率和吸附速率均相应增加：在接近人体血液pH值的条件下，CM-CTS对胆红素的吸附性能较佳：人血清白蛋白和离子强度的增加对CM—CTS吸附胆红素有明显的抑制作用。     

THE NATURE OF COLLOID AND INTERFACE OF MISCIBLE PHASE SYSTEM IN ALKALINE-SURFACTANT COMBINATION FLOODING

Several representative systems of surfactant + alkaline combination flooding are chosen to study in this paper, these systems are characterized in two points: The first: oil is miscible with water only by reversing them five to ten times, this miscible process is close to spontaneous. Interfacial tension between oil and aqueous is ultra-low. The second: this type of systems is high dispersion and can be stabilized in a period of time. These systems are observed by inicroscopy, polarizing microscopy, microcalorimetry, laser particles analysis instrument and interfacial tension meter, it is found that small particles are main constituent and special liquid crystals distributed on the surface of small particles exist. Small particles and special liquid crystals are responsible for producing ultra-low interfacial tension. The middle phase microemulsion of sodium dodecylsulfate is studied. By comparing difference and similarity between middle phase microemulsion and miscible system, mechanisms of forming low interfacial tension in miscible system and middle phase microemulsion are discussed initially.     

OXIDATIVE DEGRADATION OF BILIVERDIN AND BILIRUBIN ESTERS IN PRESENCE OF SILVER NITRATE

Treatment of biliverdin IXα dimethyl ester(2)with silver nitratein alkaline solution gave two violin-like tripyrrione carbaldehydes, one de-graded at C15-C16, other at C4-C5.Biliverdin IXα(1), bilirubin IXα(3)and its dimethyl ester(4)gave the same results.     

HA型大孔吸附树脂及活性炭对胆红素吸附性能的研究

本文选用HA型大孔吸附剂对患者血中胆红素进行了动态、静态吸附性能实验,考察了其对血液生化的影响。同时,用瑞典GAMBRO肾罐中活性炭进行了比较,实验结果表明,HA吸附剂对直接胆红素的吸附功效与进口活性基本相同,但血液生化指标HA吸附剂优于活性炭。     

苯甲醛及对溴苯甲醛光解初级过程自由基的ESR研究

苯甲醛的光解与其在放置过程中的自氧化引发机理密切相关,因此确定光解过程的主要中间产物有重要意义。自氧化的全过程比较复杂,但单纯的光解本身显然相对简单一些。本文用自旋捕捉-ESR技术研究了苯甲醛及与其相类似的对溴苯甲醛在紫外和可见光作用下生成的活泼中间体,并讨论了在本文实验条件下的光解初级过程。     

STERIC HINDRANCE IN PROPOSED PHOTOISOMERS OF BILIRUBIN

Abstract— Semi-empirical potential energy calculations have been used to examine the stabilities of the proposed geometric isomers of bilirubin. The calculations show that for either of the dipyrrole moieties, the 'anti-E' and 'syn-E' planar conformations are sterically unacceptable. The most stable form of the E isomer has the two pyrrole rings almost at right angles and in this conformation there can be no π-delocalisation between the rings.     

EFFECT OF HUMIDITY ON PHOTOINDUCED ESR SIGNAL FROM HUMAN HAIR

Abstract— Human red hairs, equilibrated at 79.8%, 58.0%, 32.3% humidity and at dry conditions, were irradiated with UV-visible (Λ > 290 nm) light. ESR intensity of the photo-induced transient free radicals was measured, at room temperature, as a function of time during and after exposure to light. Photoenhancement was found to be most pronounced in 79.8%-humidity conditioned hair and least in dry hair. The lifetimes of the transient free radicals in these samples were measured as 360s (79.8%), 180s (58.0%), 140s (32.3%), and 50s (dry). The gradual increase in lifetime as a function of humidity conditions was attributed to an increasing number of decay rates of the centers varying from fast to slow, the slow ones being unable to decay unless the fast ones do. This process is best described by a stretched exponential time function, I ( t ) = I _oexp[-( t/t _o)^α].