含噻二唑环苯甲酰脲化合物的合成及杀虫活性

用活性亚结构连接法设计合成了6个新的含1，3，4-噻二唑杂环苯甲酰脲类化合物，其结构经红外光谱、核磁氢谱、元素分析方法确证。同时对其杀虫活性进行了初步研究，发现该类化合物在普筛浓度下对淡色库蚊幼虫具有较好的杀虫活性。化合物Ⅲb(R1=Cl,R2=n-C5H11),Ⅲd(R1=CH3,R2=n-C5H11),Ⅲf(R1=2,6-difluoro,R2=-C5H11)在10mg/L浓度下对淡色库蚊幼虫的杀虫死亡率大于90％。     

Kinetic and structural characterization of human manganese superoxide dismutase containing 3-fluorotyrosines

Incorporation of 3-fluorotyrosine and site-specific mutagenesis have been used with stopped-flow spectrophotometry and pulse radiolysis to investigate the catalytic properties of human manganese superoxide dismutase (MnSOD). All of the nine tyrosine residues in each of the four subunits of the homotetramer of human MnSOD were replaced with 3-fluorotyrosine. Previous studies showed that the crystal structures of the unfluorinated and fluorinated human MnSOD are nearly superimposable with the root-mean-square deviation for 198 -carbon atoms at 0.3 Å. However, the catalytic activity k_cat/K_m of the fluorinated MnSOD at 30 μM⁻¹ s⁻¹ was less than unfluorinated wild type at 800 μM⁻¹ s⁻¹. Comparison of the values of k_cat/K_m for fluorinated and unfluorinated wild-type andY34F MnSOD showed that this decrease for the fluorinated enzyme was in significant part due to 3-fluorotyrosine residues distant (>7 Å) from the active-site metal, not to 3-fluorotyrosine at position 34 close (5 Å) to the metal. Although many rate constants for the catalysis are decreased by this fluorination, the rate of dissociation of the product-inhibited complex appears unchanged by the presence of fluorinated tyrosines. These results suggest that Tyr34 is not a proton donor in the release of the product-inhibited complex, which involves protonation of a peroxo complex of the metal with release of hydrogen peroxide.     

Preparation and characterization of nitrogen-doped TiO2 photocatalyst in different acid environments

Nitrogen-doped TiO₂ powders were successfully prepared by a wet method, i.e., a micro-emulsion-hydrothermal method, in different acid environments. Several characterization techniques, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance spectra, were combined to determine the crystal phase, concentration and chemical states of the nitrogen doped in TiO₂. The high photocatalytic activity of the nitrogen-doped TiO₂ was evaluated through the decomposition of rhodanmine B under visible light irradiation. It was suggested that the doped nitrogen formed oxynitride (NO) and produced impurity states at higher above the valence band of TiO₂. Therefore, the nitrogen doping could enhance the response of photocatalyst to the visible light and improve the photocatalytic activity because of the narrowing of band gap of TiO₂.     

Polymerization of vinyl acetate in fatty acids and properties of poly (vinyl alcohols) derived from the poly (vinyl acetates)

Polymerization of vinyl acetate (VAc) in various fatty acids (carbon numbers 4–18) was carried out. Chain transfer constants to the acids were determined to be 20–35×10^–4, from which the constant to a methylene group was obtained to be 0.73×10^–4. Viscometry in aqueous solution of derived poly (vinyl alcohol) (PVA) showed the usual behavior in terms of Huggins constant obtained by the Schulz–Blaschkes equation for PVAs derived from fatty acid systems lower than hexadecanoic acid. PVA derived from octadecanoic acid system showed abnormality, indicating association of alkyl groups. Contact angles on surfaces of PVAs cast from aqueous solutions were measured. While those of PVA derived from lower acid systems were 62°, those of PVAs derived from higher aids were higher and increased to 92° with increase in carbon number to octadecanoic acid. Alkyl groups in the PVAs were estimated to appear on the surfaces. Surface tension of aqueous solution of the PVA derived from octadecanoic acid showed high surface activity, and depended on pH of the solution, indicating the presence and cleavage of lactone ring at the combined portion between PVA and the acid.     

Evaluation of Photocatalytic Activity of Transparent Anatase Nanocrystals-Dispersed Silica Films Prepared by the Sol-Gel Process with Hot Water Treatment

Anatase nanocrystals were precipitated mainly at the surface of the silica-titania gel films with hot water treatment, whereas the addition of poly(ethylene glycol) (PEG) in the films led to the dispersion of anatase nanocrystals in the whole of the films after the treatment. Both films with and without PEG showed high photocatalytic activities for acetaldehyde, NO _x and stearic acid in the gas-solid system, and for methylene blue and potassium iodide in the liquid-solid system. The addition of PEG improved the photocatalytic activities of the resultant films due to the smaller anatase crystallites and the porous film structure. The residual silica under-layer of the superficially anatase-precipitated films is expected to act as a protective one for an organic polymer substrate against the photocatalytic degradation.     

哌嗪取代卟啉的合成、表征及其抗癌活性

设计并合成了6个具有抗癌活性的哌嗪取代卟啉化合物,分别为5,10,15,20-四[4-(4'-乙基哌嗪基)苯基]卟啉(TEPPH2,8a),5,10,15,20-四[4-(4'-丁基哌嗪基)苯基]卟啉(TBPPH2,8b),5,10,15,20-四[4-(4'-庚基哌嗪基)苯基]卟啉(THPPH2,8c),5,10,15,20-四[4-(4'-苯基哌嗪基)苯基]卟啉(TPhPPH2,8d),5-[4-(4'-乙基哌嗪基)苯基]-10,15,20-三苯基卟啉(EPTPPH2,8e)和5-[4-(4'-丁基哌嗪基)苯基]-10,15,20-三苯基卟啉(BPTPPH2,8f).这些卟啉化合物都由取代苯甲醛与吡咯缩合而成,每一个卟啉分子中含有一个或四个具有抗癌活性的取代哌嗪结构,结构经元素分析,MS,1H NMR,IR和UV-vis等表征.初步的生物活性研究表明,这些化合物具有一定的抗癌活性,因而在医学上可能具有潜在应用前景.     

Re-Evaluation of the Activity Coefficients of Aqueous Hydrochloric Acid Solutions up to a Molality of 2.0 Using Two-Parameter Hückel and Pitzer Equations. Part I. Results at 25°C

Simple two-parameter Hückel and Pitzer equations were used for the calculation of the activity coefficients of aqueous hydrochloric acid at 25°C up to a molality of 2.0 mol-kg^–1. The data obtained by Harned and Ehlers^(12,13) from galvanic cells without liquid junction were used in the analysis and the parameters obtained were compared to those obtained from all reliable data presented in the literature for HCl at this temperature. A good agreement between the parameters was always observed. The activity coefficients obtained by the new equations were compared to those suggested by Robinson and Stokes,⁽⁸⁾ Hamer and Wu,⁽¹⁾ and Pitzer and Mayorga,⁽⁹⁾ and good agreement was also found. The data from the most important literature data sets for HCl were also predicted using the new activity coefficient equations, and the magnitude of the resulting errors was close to the precision of the measurements, the errors forming an almost random pattern for all data sets.     

The ionization of sulfurous acid in Na−Mg−Cl solutions at 25°C

The stoichiometric pK ₁ ^* and pK ₂ ^* for the ionization of sulfurous acid has been determined from emf measurements in NaCl solutions with varying concentrations of added MgCl₂ (m=0.1, 0.2 and 0.3) from I=0.5 to 6.0 molal at 25°C. These experimental results have been treated using both the ion pairing and Pitzer's specific ion-interaction models. The Pitzer parameters for the interaction of Mg²⁺ with SO₂ and HSO ₃ ^– yielded =0.085±0.004, ⁽⁰⁾ = 0.35±0.02, ⁽¹⁾ = 1.2±0.04, and C = –0.072±0.007. The Pitzer parameters ⁽⁰) = –2.8±0.4, ⁽¹⁾ = 12.9±2.9 and ⁽²⁾ = –2071±57 have been determined for the interactions of Mg²⁺ with SO ₃ ^2– . The calculated values of pK ₁ ^* and pK ₂ ^* using Pitzer's equations reproduce the measured values to within ±0.04 pK units. The ion pairing model with log K_MgSO3=2.36±0.02 and log_MgSO3 = 0.1021, reproduces the experimental values of pK ₂ ^* to ±0.01. These results demonstrate that treating the data by considering the formation of MgSO₃ yields a better fit of the experimental measurements with fewer adjustable parameters. With these derived coefficients obtained from the Pitzer equations and the ion pairing model, it is possible to make reliable estimates of the activity coefficients of HSO ₃ ^– and SO ₃ ^2– in seawater, brines and marine aerosols containing Mg²⁺ ions.     

Importance of the Debye interaction in organic solutions: Henry's law constants for polar liquids in nonpolar solvents and vice versa

Henry's law constants have been determined for -butyrolactone (BL), ethyl acetate (EA), and 2-methyl-3-pentanol (MEP) in mixtures of iso-octane (ISO) and toluene (TOL), for BL, EA, TOL, and ISO in cinnamaldehyde (CIN) and for TOL and ISO in each other and in BL. From these data and published vapor pressures, the activity coefficients at infinite dilution and the standard molar Gibbs free energy of transfer, G ₂ ⁰ of the solutes from dilute solution in ISO to dilute solution in each solvent medium have been calculated. The different behavior patterns of BL and EA are attributed to differences in their abilities to exist in different conformations possessing different dipole moments. For polar solutes, G ₂ ⁰ decreases with increasing polarizability of the solvent and with increasing dipole moment of the solute, suggesting increased contributions from dipole-induced dipole (Debye) interactions. The sigmoidal plot of G ₂ ⁰ against the change in pair potential energy calculated from the classical expressions suggests that G ₂ ⁰ seriously underestimates the strength of the Debye interactions in comparison with the London interactions.     

红厚壳属植物化学成份及药理活性研究进展

综述了近年来对红厚壳属植物中的化学成分及药理活性研究，重点讨论了18种 红厚壳属植物中Zhao吨酮类，香豆素类，黄酮类和萜类的化学成分，并讨论了它们 的药理活性。