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关键词： liposomes   structure-activity relation   antibacterial activity   L-prolinol derivatives   synergistic effect  

摘要： Although liposomes are largely investigated as drug delivery systems, they can also exert a pharmacological activity if devoid of an active principle as a function of their composition. Specifically, charged liposomes can electrostatically interact with bacterial cells and, in some cases, induce bacterial cell death. Moreover, they also show a high affinity toward bacterial biofilms. We investigated the physicochemical and antimicrobial properties of liposomes formulated with a natural phospholipid and four synthetic L-prolinol-derived surfactants at 9/1 and 8/2 molar ratios. The synthetic components differ in the nature of the polar headgroup (quaternary ammonium salt or N-oxide) and/or the length of the alkyl chain (14 or 16 methylenes). These differences allowed us to investigate the effect of the molecular structure of liposome components on the properties of the aggregates and their ability to interact with bacterial cells. The antimicrobial properties of the different formulations were assessed against Gram-negative and Gram-positive bacteria and fungi. Drug-drug interactions with four classes of available clinical antibiotics were evaluated against Staphylococcus spp. The target of each class of antibiotics plays a pivotal role in exerting a synergistic effect. Our results highlight that the liposomal formulations with an N-oxide moiety are required for the antibacterial activity against Gram-positive bacteria. In particular, we observed a synergism between oxacillin and liposomes containing 20 molar percentage of N-oxide surfactants on Staphylococcus haemolyticus, Staphylococcus epidermidis, and Staphylococcus aureus. In the case of liposomes containing 20 molar percentage of the N-oxide surfactant with 14 carbon atoms in the alkyl chain for S. epidermidis, the minimum inhibitory concentration was 0.125 mu g/mL, well below the breakpoint value of the antibiotic.

关键词： benzene derivatives   Ev-degree   physico-chemical properties   quantitative structure-property relationship   styrene-butadiene rubber   topological indices   Ve-degree  

摘要： A quantitative structure-property relationship study was performed for the prediction of physical properties of 22 benzene derivatives using ev-degree and ve-degree topological indices. A topological index is designed by transforming a chemical structure into a numeric number. These topological indices correlate certain physico-chemical properties like molecular weight, enthalpy, boiling point and pi-electron energy of beta-unit of benzene derivatives. At first, a simple linear regression model was developed using ve-degree and ev-degree topological indices and the certain physical properties of the considered benzene derivatives. It is found that the atom bond connectivity index (ABCve) possesses the best correlating ability among several topological indices to predict the boiling point, the ve-degree based Randic index Rve is the best predictor of enthalpy, the ev degree based Randic index Rev is the best predictor of pi-electron energy, the sum connectivity index chi ve is the best predictor of molecular weight. Second, multiple linear regressions were used for prediction the physical properties (molecular weight, boiling point, enthalpy and pi-electron energy of beta-unit) on the basis of six predictor such as M1 beta ve, M2 beta ve, GAve, chi ve, Rve, and Hve indices. This multi-linear regression model shows the 100% variation in pi-electron energy of beta-unit. A Maple software based algorithm is used for the calculations of topological indices and the statistical analysis is performed with the SPSS software. The calculations of the ev and ve degree based topological indices of chemical structure of styrene-butadiene rubber are presented at the end to illustrate the given Maple algorithm.

关键词： Caffeine   thermodynamic parameters   conductance   surface tension   interactions   surfactants  

摘要： Effect of caffeine on the micellization of anionic surfactant ( SDS), cationic surfactant (HTAB) and non-ionic surfactant (Tx-100) was investigated using the conductometric and tensiometric techniques. The thermodynamic parameters such as change in Gibbs-free energy, Delta G(m)(0), change in enthalpy of micellization, Delta H-0(0), change in entropy of micellization, Delta S-m(0), change in Gibbs-free energy of transfer, Delta G(m,trans)(0), surface excess concentration, G(max), minimum area per surfactant molecule, Amin :, surface pressure,.cmc, change in Gibbs-free energy of adsorption, Delta G(0) ads and other related parameters were calculated to gain insights into the interactions of caffeine with different surfactants at different temperatures. The CMC in mole fraction units, Pi C-CM, values of SDS in caffeine are low, while that of HTAB are large in comparison with the values reported in water. The negative values of Delta H-m(0) and Delta G(m)(0) and the positive values of Delta S-m(0) are indicative of SDS-caffeine and HTAB-caffeine interactions.

关键词： 过渡态理论   知识点   诺贝尔奖   科研  

摘要： 针对物理化学教学中较抽象的理论知识点,从诺贝尔奖,经典文献,最新科研成果三个方面科教融合重构课程内容,围绕过渡态理论,介绍超快激光以及最新的分叉势能面理论,使知识点内容具体化、形象化和系统化,从而加深学生对过渡态曲线势能面、马鞍点及活化能等知识点的理解,培养学生科研素质和创新思维。

关键词： 物理化学   信息化教学   实施  

摘要： 为适应时代发展,提高学生学习效率,本文对高职《物理化学》课程从课前、课中、课后、拓展四个方面进行了信息化教学设计和实施,结合已建好的《物理化学》优慕课网络教学平台,多种信息化教学手段结合使用,并适时引入课程思政,突出了学生的主体地位,突显了教师的主导地位,“线上”与“线下”双管教学,取得了较为理想的学习效果,可为同样奋斗于教学一线的高职高专教师提供信息化课程设计参考。

关键词： 布雷顿循环   卡诺循环   热力学   物理化学   教学研究  

摘要： 本文通过对我校矿物加工工程本科专业的物理化学教学中引入超临界CO_(2)布雷顿循环的相关知识进行的实践,使得学生对卡诺循环和热力学第二定律的理解进一步加深了,同时由于紧密结合了目前碳达峰碳中和以及减排增效等热点问题,使得同学们对物理化学的学习兴趣得以提升,对物理化学整体知识体系有了更加全面的掌握,从而取得了良好的教学效果。

关键词： 物理化学   团队建设   课程思政   教学改革  

摘要： 指出了高校教学团队建设对课程思政教学的意义,分析了现有团队建设中存在的部分问题。从师资队伍建设、课程建设、教学研究等方面,对高校物理化学课程思政教学团队的建设提出了相应的方案。为我国高校物理化学课程思政教学团队建设研究提供了重要参考。

关键词： 字母符号   规范书写   量和单位   化学元素   分子物理学   物理化学   核素符号   正体  

摘要： 根据GB3102.8-93《物理化学和分子物理学的量和单位》的规定,现将化学元素和核素符号书写的规范要求介绍如下:①元素或核素的单字母符号均用正体大写,双字母符号首字母正体大写,第二个字母用正体小写。

关键词： Nigella sativa   Microencapsulation   Spray drying   Thymoquinone   Inulin  

摘要： Black cumin seed oil has high nutritional value. However, due to its peppery taste, strong odor, and rapid oxidative deterioration, its application in food formulations has been limited. Encapsulation techniques with hydrocolloids combined with other nutritive wall materials may overcome these problems and provide more health benefits for consumers. For these reasons, cold-pressed black cumin seed oil was microencapsulated by spray drying in four different microcapsule models, including gum arabic alone (GA) and in combination at a 50:50 ratio with maltodextrin (GM), inulin (GI), or whey protein (GW). The microencapsulation efficiency of GA presented the highest yield of up to 88%. Replacing 50% of the gum arabic with whey protein (GW) reduced the microencapsulation efficiency from 88 to 75% while GI and GM were 86.12 and 83.51, respectively. The wettability and solubility of the microencapsulated powders prepared (GI, GM, and GW) were superior to those of the microcapsules prepared by gum arabic alone. Under SEM, the GA and GM powders collapsed at the surface, while the GI and GW powders were spherical and smooth. The highest thymoquinone content was found in the GI powder. There were no differences (P.0.05) in the thymoquinone content observed among all powders.

关键词： 课程思政   物理化学   高校教学  

摘要： 课程思政是课程教学之魂。本文从教学目标、教学内容、学习理论和思政教育4个维度给出了课程思政本质内涵的认知,结合新时代高等教育课程教学新要求,给出了在符合情感态度品德教育理论的前提下实施课程思政的教学方法。以《物理化学》课程为例,根据其课程思政目标内容,进行了课程思政点、线、面、体的整体内容设计和教学策略设计;根据“格物-致知-明德”教育理念,基于“CEPRAE”六步基本教学法,设计并实施了课程思政生成性课堂教学模式,教学实践表明,“格物-致知-明德”的课程教学在更新教学观念、紧跟时代需求、创新教学内容、应用信息技术、立足课程思政和开展对外交流等方面均表现了很好的成效。