H_5N_1亚型禽流感病毒血凝素基因的克隆及分子进化分析

目的　克隆H5N1 亚型禽流感病毒HA基因并进行分子进化分析。方法　应用RT PCR方法 ,以 2株H5N1 亚型禽流感病毒RNA为模板 ,扩增了HA全基因cDNA。将HAcDNA基因克隆于pUCm T载体 ,并对其进行了测序。结果　所克隆的HA基因全长为 1731bp ,共编码 5 6 8个氨基酸。将该毒株与其它 10株H5亚型禽流感病毒HA基因序列核苷酸及氨基酸进行比较 ,其核苷酸同源性在 80 5 %～ 99 2 %之间 ,氨基酸序列同源性在 89 4 %～98 6 %之间。高致病性毒株HA基因裂解位点存在多个碱性氨基酸插入。结论　为禽流感基因工程疫苗的研制奠定了基础 ,同时通过分子进化分析也揭示了各毒株间的亲缘关系。     

Shear-induced interactions in blends of HMMPE containing a small amount of thermotropic copolyester HBA/HQ/SA

Shear-induced interactions between high molecular mass polyethylene (HMMPE) melt and a thermotropic liquid crystalline copolyester, HBA/HQ/SA (TLCP) were investigated using large amplitude oscillatory shear and capillary shear. Polarized optical microscopy (POM) observations show that the mono-domain nematic TLCP droplets embedded inside a HMMPE melt may be readily elongated using large amplitude oscillatory shear. The HMMPE melt adjacent to the elongated TLCP filament was observed to crystallize faster than that in the matrix away from the interface. TEM analysis on the 1 wt% TLCP/HMMPE blend quenched after capillary shear shows that there are strong interfacial interactions between the elongated TLCP filament and the HMMPE matrix. Long range PE lamellae orientational order up to 2 μm away from the TLCP filament surface were observed, with all the lamellae surface normal parallel to the TLCP fiber. Additionally, a strong interfacial compatibility between the TLCP filament and the HMMPE matrix with an interfacial thickness of ∼30 nm has also been observed. The enhanced interfacial compatibility is attributed to the -CH₂- group interactions due to chain alignment in both components at their interface. These results provide a fundamental insight to other TLCP containing thermoplastics where compatibilities may be present due to segmental interactions.     

Catching a molecule at the air-water interface: Dynamic pore array for molecular recognition

As a soft and flexible porous structure, a pore array of a steroid cyclophane SC(OH), which consists of the rigid 1,6,20,25-tetraaza[6.1.6.1]paracyclophane ring connected to four steroid moieties (cholic acid) through flexible L-lysine spacers, was prepared at the air-water interface. As confirmed by surface pressure (π)-molecular area (A) isotherms, transition between open conformation and cavity conformation of the SC(OH) molecule was reversibly induced upon repeated compression and expansion of its monolayer at pH 11 where amino groups of the lysine residues are not fully deprotonated. Capture and release of an aqueous fluorescent guest (TNS) by SC(OH) was observed upon dynamic cavity formation through surface fluorescence spectroscopy. At pH 12, dynamic cavity formation of SC(OH) was sufficiently suppressed, and the capture and release of an aqueous TNS by the monolayer was not virtually observed. Lessened electrostatic repulsion between the SC(OH) molecules due to conversion of ammonium to free amine may prevent the cavity from reopening. The importance of dynamic nature of cavity formation on the guest binding was also proved by control experiments using SC(H), which cannot form cavity conformation at any surface pressures at both pH 11 and 12.     

Phenol adsorption on porous and non-porous carbons

Phenol physisorption on a series of porous and non-porous amorphous carbons was studied at 298 K. Grand Canonical Monte Carlo computer simulations were performed to simulate phenol adsorption from the gas phase. Phenol is adsorbed in a solid-like state within the pores and there is no well-developed multilayer regime. The ‘t’ plot method was adapted to phenol adsorption and the results obtained are in agreement with the model solids employed. The simulated adsorption isotherms were compared with experimental results obtained for adsorption from aqueous solutions of phenol. BET surface areas were calculated. Other characteristics of the adsorption system analyzed were: adsorption energy distribution functions, density profiles, distribution of molecules according to gas-solid energy, and local isotherms.     

反应型共聚物相容剂在聚合物合金中的应用

反应型共聚物相容剂所含的反应官能团与共混物中聚合物的相关的官能团发生化学反应，从而改善不相容聚合物共混物的相容性。本文介绍了反应型共聚物相容剂的分子设计，合成及其应用。     

Rheological behaviour of polysaccharide aqueous solutions

Several data relative to the viscosity of water-soluble polysaccharide solutions were collected from the literature and processed by different rheological models. Some relationships between the viscosity of these polymer solutions, their molecular weight and their solution concentrations, were established and their validity checked. Thus, an accurate equation correlating the viscosity and both the shear rate and the solution concentration of different water soluble polysaccharides (xanthan, hyaluronan, carboxymethylcellulose) was deduced on the basis of Cross' model which suggests two domains in which the viscosity is constant, i.e. very low and very high shear rate ranges. Then, an expression relating the zero-shear viscosity (A) and the concentration of their solutions was proposed. Finally, an alternative equation to that of Mark–Houwink correlating the molecular weight and the intrinsic viscosity of the water-soluble polysaccharides studied in this paper was found.     

Aerobic selective oxidation of (hetero)aromatic primary alcohols to aldehydes or carboxylic acids over carbon supported platinum

The synthesis of substituted benzaldehydes, benzoic acids, heterocyclic aromatic aldehydes and acids has been studied via the oxidation of the aromatic alcohols with air under mild pressure (<20 bar) at 100 °C, in the presence of a 1.95 wt.% Pt/C catalyst. The solvent was found to play the most important role in determining the selectivity of the oxidation products. Changing the solvent enabled tuning the reaction either to the aldehyde (pure dioxane), or the carboxylic acid (dioxane/aqueous solution without or with addition of sodium hydroxide). This oxidation method allowed to effectively oxidize many substituted benzylalcohols with various electron-releasing or -attracting groups (NO₂, Me, OMe, Cl, Br, OH, phenyl, …) and heterocyclic alcohols including nitrogen and sulphur atoms (2-thiophenemethanol, 2- and 4-pyridine methanol compounds).     

Are quantum dots ready for in vivo imaging in human subjects?

Nanotechnology has the potential to profoundly transform the nature of cancer diagnosis and cancer patient management in the future. Over the past decade, quantum dots (QDs) have become one of the fastest growing areas of research in nanotechnology. QDs are fluorescent semiconductor nanoparticles suitable for multiplexed in vitro and in vivo imaging. Numerous studies on QDs have resulted in major advancements in QD surface modification, coating, biocompatibility, sensitivity, multiplexing, targeting specificity, as well as important findings regarding toxicity and applicability. For in vitro applications, QDs can be used in place of traditional organic fluorescent dyes in virtually any system, outperforming organic dyes in the majority of cases. In vivo targeted tumor imaging with biocompatible QDs has recently become possible in mouse models. With new advances in QD technology such as bioluminescence resonance energy transfer, synthesis of smaller size non-Cd based QDs, improved surface coating and conjugation, and multifunctional probes for multimodality imaging, it is likely that human applications of QDs will soon be possible in a clinical setting.     

Structure-activity relationship observations for European corn borer moth pheromone and fluoro analogs via computer molecular modeling

Structure-activity relationship (SAR) observations were made for theZ-type European corn borer moth pheromone, (Z)-11-tetradecen-1-ol acetate, and a series of analogs with fluorination in the alcohol portion of the molecule. The attractiveness of these analogs and the pheromone was compared to the electrostatic potential map of the molecular mechanics (MM) minimized lowest energy conformation for each compound. A critical range of electrostatic potential on the protons of the double-bond appears to be essential for optimal acceptor fit and attractiveness.     

不同分子量聚酯的羟值分析方法

用醋酐／高氯酸／乙酸乙酯法，醋酐吡啶回流法，分别对相对分子质量为１１００－１２０００的聚酯进行了羟值的测定，并用气压渗透法和析出物溶解重滴法进行了核对。结果表明醋酐／高氯酸／乙酸乙酯法对于Ｍ〈５０００的聚酯是适用的，而高分子量的聚酯则必须用醋酐／吡啶回流法，才能获得满意的结果。