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关键词： biomaterials   composites   drug delivery systems   gels   polysaccharides  

摘要： Natural bio-based materials used in wound dressings have been continuously developed in recent years, and have certain advantages in water retention, biocompatibility, and therapeutic properties. Konjac glucomannan (KGM) is a kind of plant polysaccharide with good cell compatibility and gel properties. Various gels obtained by modification of KGM through physical and chemical methods have great application potential in wound excipients. In the past few years, various KGM-based wound barrier materials such as hydrogels, xerogel, microspheres, films, and fibers have been continuously researched and developed. The combination of KGM and other polymers can improve the problem of poor mechanical properties and give it new functional properties, which is beneficial to the moisturizing of the wound surface and the release of drugs to promote wound healing. This article reviews the physicochemical properties of KGM and the latest developments in KGM-based composite gels, reveals the relationship between molecules in KGM-based composite gels, and looks forward to the research and development prospects of KGM-based composites in wound dressings.

关键词： Plasma treatment   Starch nanocrystals   Multiscale structure   Physicochemical properties   Rheology  

摘要： Non-thermal plasma has increasingly been used for surface modification of various materials as a novel green technology. In this study, we prepared potato starch nanocrystals (SNCs) assisted by dielectric barrier discharge plasma technology and investigated its multiscale structure, physicochemical properties and rheology. Plasma treatment did not change the morphology and crystalline pattern of SNCs but reduced the crystallinity. The amylose content, swelling power, gelatinization temperature, and apparent viscosity of SNCs decreased after the plasma process by depolymerizing the amylopectin branch chains and degrading SNCs molecules. Besides, plasma increased the rapidly digestible starch and resistant starch content. Changes in rheological properties of plasma treated SNCs suggested that the plasma process increased the flowing capacity. The effective structural and functional changes of plasma treated SNCs confirm that plasma technology has great potential for modification of SNCs.

关键词： Protein powder   Subcritical dimethyl ether extraction   Digestive properties   Rheological properties  

摘要： The process-related physicochemical, digestive and rheological properties of protein prepared by subcritical dimethyl ether extraction (SDEE) were comprehensively investigated and compared with those obtained by pHshift, to study the industrial potential of SDEE. Two different materials from tuna (meat and liver) were studied in parallel, and SDEE had similar effects on the proteins in them. The protein component was almost unchanged before and after SDEE, while the content of water-soluble protein and alkali-soluble protein was substantially reduced and increased after pH-shift, respectively. We also found that SDEE had superior ability to pH-shift to conserve light metals, remove lipids and heavy metals, and maintain protein structure. Furthermore, SDEE-produced protein powders were easier for humans to digest, and their gelation and emulsification were also superior to those prepared by pH-shift. The aforementioned results suggest that SDEE can remove more impurities, and the obtained protein has outstanding potential in industrial applications.

关键词： fluorine   cycloalkanes   lipophilicity   acidity and basicity   metabolic stability  

摘要： The CF2 dragon reborn! The difluoromethylene dragon has evolved from difluorocyclopropanations (presented in a series of previous covers, see Adv. Synth. Catal., DOI: 201801304 and Eur. J. Org. Chem. 201900911) to the full strength of all other gem-difluorocycloalkanes. In the Research Article by O. O. Grygorenko and co-authors (DOI: 10.1002/chem.202200331), the key in vitro properties of functionalized gem-difluorinated cycloalkanes (pKa, log P, aqueous solubility, and intrinsic clearance) are discussed thoroughly.

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。