Lower consolute temperature in a non-aqueous surfactant system

The phase behaviour of the system triethylene glycol dodecyl ether/formamide has been investigated at varying temperatures. The system has a lower consolute temperature (L.C.T.) at 16 °C for a critical concentration 10 w% surfactant. The addition of water lowers the L.C.T. and addition of charged surfactant raises it.     

Theory of quantum dynamics in fermionic environment: An influence functional approach

Quantum dynamics of a particle coupled to a fermionic environment is considered, with particular emphasis on the formulation of macroscopic quantum phenomena. The framework is based on a path integral formalism for the real-time density matrix. After integrating out of the fermion variables of the environment, we embed the whole environmental effects on the particle into the so-called influence functional in analogy to Feynman and Vernon's initial work. We then show that to the second order of the coupling constant, the exponent of the influence functional is in exact agreement with that due to a linear dissipative environment (boson bath). Having obtained this, we turn to a specific model in which the influence functional can be exactly evaluated in a long-time limit (long compared to the inverse of the cutoff frequency of the environmental spectrum). In this circumstance, we mainly address our attention to the quantum mechanical representation of the system-plus-environment from the known classical properties of the particle. It is shown that, in particular, the equivalence between the fermion bath and the boson bath is generally correct for a singlechannel coupling provided we make a simple mapping between the nonlinear interaction functions of the baths. Finally, generalizations of the model to more complicated situations are discussed and significant applications and connections to certain practically interesting problems are mentioned.     

A trans influence study in propyl (aquo)cobaloxime by imidazoles and amino acids

Substitution reactions of propyl cobaloxime with imidazole, substituted imidazoles, histidine, histamine, glycine and ethyl glycine ester are carried out as a function of pH. Trends in the formation constants are explained based on the steric hindrance, extent of π-bonding and Σ-donor capacity of the incoming ligand. Molecular mechanics is used to theoretically determine the bond length and bond strain values by MM2 parametrization and these are correlated with the experimental data.     

舒适护理对剖宫产产妇术后应激反应及疼痛的影响

目的探讨舒适护理对剖宫产产妇术后应激反应及疼痛的影响。方法选取2012年6月至2015年4月来江西省丰城市泉港镇卫生院行剖宫产的足月产妇74例为研究对象。按照入院顺序抽签后随机分为实验组和对照组,对照组孕产妇采取常规护理,对孕产妇进行手术前的准备工作,做好手术中的生命体征监测,术后做好全面的护理。在此基础上,实验组孕产妇进行舒适护理。观察产妇SAS评分、各项临床观察指标时间。结果实验组产妇术后第3 d SAS评分低于对照组(P0.05)。实验组肛门排气恢复时间、下地活动时间、泌乳时间均低于对照组(P0.05)。实验组产妇术后24 h CORT水平低于对照组(P0.05)。结论舒适护理可改善产妇疼痛,减少应激反应。     

New Ru(II)–dmso complexes with heterocyclic hydrazone ligands towards cancer chemotherapy

The synthesis and characterization of ruthenium(II) complexes, [RuCl₂(dmso)₂(bfmh)] (1; dmso = dimethyl sulfoxide, bfmh = benzoic acid furan-2-ylmethylene-hydrazide), [RuCl₂(dmso)₂(btmh)](2; btmh = benzoic acid thiophen-2-ylmethylene-hydrazide), [RuCl₂(dmso)₂(bfeh)](3; bfeh = benzoic acid (1-furan-2-yl-ethylidene)-hydrazide) and [RuCl₂(dmso)₂(bpeh)](4; bpeh = benzoic acid (1-pyridin-2-yl-ethylidene)-hydrazide) are described. The ligands, when treated with either cis-[RuCl₂(dmso)₄] or trans(Cl)–[RuCl₂(dmso)₂(bpy)], resulted in the same products. This has been confirmed by IR spectra and single crystal X-ray diffraction studies. The redox behaviors of the complexes have been found to be strongly dependent on the electronic nature of the moieties present in the hydrazone ligands. The binding of the complexes to Herring sperm DNA has been studied by absorption titration and cyclic voltammetry. But, due to the random change in the absorption on the addition of DNA, only a qualitative result rather than a quantitative result has been obtained. All the complexes have been found to bind DNA through different modes to different extents. The antibacterial properties of the ligands and the complexes have been studied against five pathogenic bacteria and also the minimum inhibitory concentrations (MIC) of all the ligands and complexes 2 and 4 have been evaluated.     

Calorimetric studies on renaturation by CaCl2 addition of metal-free α-amylase from Bacillus Licheniformis (BLA)

In our previous work we characterized the Ca binding properties of BLA by analysis of Ca-induced renaturation in the presence of urea. In this study we focused on the renaturing capacity of CaCl₂ in the absence of urea and analysed the apparent thermodynamic and kinetic properties of renatured BLA by DSC, CD and dynamic light scattering (DLS) measurements. Ca-free protein did not return fully to the native state even after extensive dialysis against high concentrations of calcium. Thus Ca removal provokes changes in protein structure that can not be reversed completely even by addition of an excess of calcium. However, activity studies performed simultaneously with the DSC experiments showed a significant return of enzymatic activity despite the failure of complete return of native stability. This conclusion is in excellent agreement with findings of Machius et al. who suggested on the basis of their X-ray studies that it is not possible to remove CaI and CaII without introducing significant structural changes. It is important to note that all unfolding reactions of metal-free, partially renatured and native protein were found to be irreversible. Therefore the DSC transition curves were fitted using irreversible transition models. It turned out that the apparent heat capacity profiles of partially renatured BLA could be well represented by superposition of two irreversible processes each following the two-state irreversible model.     

一种双光束红外光谱及其在气固相多相催化反应实时原位表征中的应用

单光束红外光谱技术(原位傅立叶透射变换红外、原位漫反射红外和衰减全反射红外光谱技术)虽然已经用于气固相多相催化反应的原位表征中,但这些光谱在真实反应条件下会受到气体分子振动光谱和加热条件下产生的发射光谱的严重影响,不能实时获得催化剂表面的真实信息.另外,由于在真实的气固相多相催化反应过程中,催化剂本底的信息会随着反应时间的延长而发生变化,因此单光束红外光谱技术在扣除本底信息方面存在误差.为了实现在反应条件下,实时、原位表征催化剂表面的状态,我们报道了一种双光束红外光谱表征技术.该技术包括双光束红外光谱系统及双光束红外反应池.其特征在于:实时双光束原位红外光谱系统由两台完全相同的红外光谱仪和双光束红外反应池组成.双光束红外反应池由完全相同的样品池和参考池连接而成,样品池和参考池处于同一水平线上分别对应于样品光谱仪和参考光谱仪,由计算机同步控制两台红外光谱仪,排除实时状态下的气体分子振动光谱干扰和加热条件下产生的发射光谱干扰.该技术可以对真实反应条件下的气固相多相催化反应进行实时原位表征.通过应用程序的关联可以实时、同步采集样品光束和背景光束谱图来得到催化剂表面物种随反应时间变化的真实信息.该技术克服了单光束红外光谱在原位多相催化反应表征方面的缺陷,使表征结果变得更加精确可靠.该技术还可以在变化的气相组分条件下,获得不同温度下、实时的催化剂表面活性中心、活性相和中间物种的信息.采用上述双光束红外光谱仪对丁烯在纳米HZSM-5催化剂上芳构化反应过程进行了实时、原位观测,首次在实际反应条件下,观察到了异丁烯在纳米HZSM-5沸石的表面Br?nsted酸中心上经历吸附、活化、聚合、环化等反应步骤生成芳烃的过程.     

基于虚拟变形法的车-桥耦合系统移动质量识别

利用双自由度质量-弹簧阻尼模型模拟移动车辆, 并基于虚拟变形(VDM)方法的结构快速重分 析思想, 提出一种车-桥耦合系统的移动质量快速识别的有效方法. 该方法以双自由度车体模 型的质量为变量, 通过最小化桥体结构实测响应和计算响应的平方距离来识别移动质量 (载荷), 避免了识别载荷时常遇到的病态问题, 对噪声鲁棒性强, 且需要传感器信息少. 每步优化 中, 利用在VDM方法基础上提出的移动动态影响矩阵概念, 无需时时重构车-桥耦合系统的时 变系统参数矩阵, 显著提高了计算效率. 利用数值框架梁模型, 通过比较不同车辆简化模型 对移动体质量及等效移动载荷的识别效果, 验证了该方法的可行性和有效性, 即使在5% 的噪声影响下, 利用一个传感器可以准确地识别多个移动体的质量.     

Theoretical Study of the Intramolecular Proton Transfer in the Tautomers of Cytosine Assisted by Water

Ab initio MP2 and DFT studies on the tautomers of cytosine and the related hydrated tautomers have been carried out. The ground‐state structures of four tautomers of cytosine and related transition states were fully optimized. The vibrational frequency analysis was performed on all the optimized structures. Detailed intrinsic reaction coordinate (IRC) calculations were carried out to guarantee the optimized transition‐state structures being connected to the related tautomers. We obtained the relative stability order for the tautomers of cytosine and the related hydrated tautomers. In the isolated and hydrated condition, the bond types of C(2) O(7) and C(4) N(8) greatly affect the stability of the cytosine tautomers. Moreover, we have explored the influence of the water molecules on the intramolecular proton transfer between the keto and enol forms of the cytosine tautomers. The first water molecule obviously decreases the isomerization activation energy for the monohydrated cytosine tautomers. It is shown that the isomerization energy barrier changes only a little when the second and third water molecules are added in the reaction loop. The solvent effects have an obvious influence on the proton‐transfer barrier of the isolated cytosine. However, the solvent effects seem to be insignificant for the isomerization energy barriers of the monohydrated, dihydrated and trihydrated cytosine. The water molecule in these complexes can be looked on as the explicit water. Therefore, the explicit water model may be more credible to explore the intramolecular proton transfer, in comparison with the PCM which is the implicit water model.     

SAPO分子筛的合成及影响因素的研究进展

本文综述了SAPO分子筛的主要合成方法,包括水热合成法、气相晶化法、液相晶化法、微波合成法、变温陈化法、超声合成法、程序升温法等方法.讨论了反应物的组成、模板剂、酸碱度、介质、晶化温度、晶化时间等因素对SAPO分子筛合成的影响.最后对SAPO分子筛合成方法进行了展望.