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关键词： Chitosan   Carrageenan   Gum Arabic   Selenium nanoparticle   Physicochemical stability   Bioactivities   Application  

摘要： To meet the increasing demand for polysaccharide-stabilized selenium nanoparticles (PS-Se degrees NPs) for industrial applications, in this study, we employed three commonly-used polysaccharides (i.e. chitosan (CS), carrageenan (Cg) and Gum Arabic (GA)) to fabricate Se degrees NPs, and compared their functional properties and their physicochemical stabilities, under varying conditions (ionic strength, pH, and temperature). The results showed that CS-SeNPs had higher storage stability but easily aggregated in 500 mM NaCl or at pH > 8 because of their surface cationic groups. This, however, improved their DPPH free radical scavenging and antitumor activities. Compared to CS-SeNPs, the anionic groups in Cg-Se degrees NPs increased their resistant to pH variations and reduced cellular toxicity, and the multi-branched structure of GA-Se degrees NPs increased their thermal stability. Overall, this study shows that the behaviors of PS-SeNPs depends mainly on ionizable functional groups and the structure of polysaccharides, contributing to the development of PS-Se degrees NPs with applicability in the food and pharmaceutical industries.

关键词： 物理化学问题   数学思想方法   应用举例  

摘要： 本文阐述将数学思想方法应用于求解物理、化学题中的具体做法,讲解利用均值不等式、函数图象、几何知识与三角函数求解物理题的方法,利用分类讨论思想、不完全归纳法、方程思想、立体几何知识解答化学题的方法,以培养学生的综合能力。

关键词： Aged hydrochar   Elemental composition   Pore structure   Thermodynamic stability   Dissolved organic matter  

摘要： The importance of hydrochar properties for soil application is well known, but the effects of natural aging on hydrochar properties remain ambiguous. The present study aimed to determine the shift patterns in the physicochemical properties of hydrochar through a 16-month soil column aging experiment conducted in a rice-wheat rotation system with hydrochars derived from a wheat straw at 220 degrees C and 260 degrees C. Obvious decreasing hydrophilic/polarity indices and increasing porosity, ash content, and stability occurred in aged hyrdrochar, which were due to the dissolved organic matter (DOM) leaching and the interaction with mineral content and fertilizer during the 16-month aging process. Besides, fewer C-OH, slightly more C=O, and higher aromaticity (C-C/C=C) in aged hydrochar were observed. Meanwhile, the relative abundance of the compounds containing only C, H, and O atoms in water extract of aged hydrochar decreased, while that of the compounds containing C, H, O, and N atoms increased during aging;these findings were attributed to the less labile DOM and microbial degradation and the retention of some plant-derived dissolved organic carbon, respectively. This study provided 16-month aging characterization data regarding alteration in hydrochar physicochemical properties, which was conducive to make a better understanding of the use of hydrochars as sustainable soil amendments from agroecosystems and environmental perspective. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Antimicrobial activity   Complexation   Lysozyme   SAIL  

摘要： A new biodegradable, caffeine and dioctyl sulfosucci nate (AOT) based surface active ionic liquid (SAIL) has been synthesized and investigated for its complexation with lysozyme (LYZ) to develop antimicrobial SAIL-LYZ colloidal complexes with enhanced activity. Interfacial properties of the formed SAIL-LYZ colloidal complexes in the aqueous medium have been investigated using tensiometly, while the complexation in bulk has been monitored with dynamic light scattering, zeta-potential and turbidity measurements. Fluorescence and circular didiroism studies have been employed to gain insight about the structural modification of LYZ on complexation with SAIL. Isothermal titration calorimetry has been employed to monitor the thermodynamics of complexation of SAIL with LYZ, whereas the binding behavior of SAIL with LYZ has been investigated using molecular docking. Further, the antimicrobial activity of SAIL-LYZ complexes has been investigated against Gram-positive and Gram-negative bacteria. Fascinatingly, depending upon the concentration of SAIL SAIL-LYZ colloidal complexes have been found to exhibit enhanced antimicrobial activity as compared to control and the known antibiotics. It is anticipated that the present study of new colloidal complexes of SAIL with enzymes would be helpful in various biomedical applications. (C) 2020 Elsevier B.V. All rights reserved.

关键词： 物理化学   课程思政   教学改革  

摘要： 本人早期自发地在物理化学课程中加入思政元素,收到了较好的教学效果,因此体会到课程思政是可行的,也是必要的。在分析以往教学中存在的问题的基础上,主动提高思想认识,深刻领会思政内涵,自觉整合知识体系,深挖思政元素,不断探索实践,把思政元素真正融于物理化学专业课教学之中,实现知识传授与价值引领的同向同行。

关键词： beta-carotene loaded nanoemulsion   Antioxidant   Stability   Cold plasma   Accelerated test  

摘要： The effects of water soluble antioxidant (ascorbic acid and EDTA), fat soluble antioxidant (alpha-tocopherol) and amphiphilic antioxidant (ascorbyl palmitate;AP) on the chemical physics and bioaccessibility of beta-carotene loaded nanoemulsions (CNE) were investigated. During accelerated storage at 45 degrees C for 15 days, AP showed the highest protective actions against particle size growth, color fading, lipid oxidation, and beta-carotene degradation in CNE (p < 0.05). CNE with AP was then subjected to treat with cold plasma (CP) induced reactive species system under various powers and contact times compared to control. AP was able to protect physical and oxidative stabilities of CNE as well as beta-carotene integrity. The highest in vitro lipid digestibility, bioaccessibility and beta-carotene stability were found in CNE with AP (p < 0.05). However, those properties were lowered after CP exposure. The results indicated that AP was a promising antioxidant in improving physical stability, oxidative stability, beta-carotene retention, and beta-carotene bioaccessibility of CNE.

关键词： 课程思政   物理化学   社会主义核心价值观  

摘要： 本文以厚植社会主义核心价值观中的公民基本道德规范为目的,从"两个目标、三大支柱和四种氛围营造"构建物理化学课程思政体系,从物理化学发展史和我国著名科学家科研和生平出发,挖掘物理化学课程思政范例,并从科研和人文角度剖析,力求增强学生的学习热情和孜孜以求的探索精神,为培养新工科的高素质人才服务。

关键词： 《中国科学》   中国科学院院士   国家科学院院士   《科学通报》   绿色化学   博士生导师   交叉研究   物理化学  

摘要： 韩布兴,中国科学院化学研究所研究员、博士生导师、中国科学院院士、发展中国家科学院院士、英国皇家化学会会士,主要从事物理化学与绿色化学的交叉研究. 2008年至今担任《中国科学:化学》编委, 2008~2014年担任《科学通报》编委, 2014年至今担任《科学通报》(中文版)副主编.2020年是《中国科学》和《科学通报》(简称"两刊")创刊70周年,《中国科学》杂志社专访韩布兴院士,请他分享在"两刊"的工作体会.

关键词： 课程思政   物理化学   教学改革  

摘要： 随着新时期高校课程改革的如火如荼推进,融合了专业知识教育和思政教育的课程思政教学模式受到广大高校教师的一致青睐,对学生的自主学习能力发展以及情感价值态度培养发挥有积极作用。在新课程改革背景下,高校物理化学课程教师也应该积极针对课程思政展开教学探索,发挥思想政治理论和专业理论的协同育人作用,以严谨的治学态度为学生带来全新的课程体验。

关键词： Lipase   Deep eutectic solvent   Esterification activity   Physical and chemical properties  

摘要： With its unique physicochemical properties, deep eutectic solvents (DESs) can efficiently regulate the effect of enzyme activity. The present study investigated the correlation between catalyzed synthesis activity of lipase N435 and physicochemical (conductivity, surface tension, pH and viscosity) properties of several choline chloride (ChCl)-based DESs, ChCl: urea, ChCl: ethylene glycol and ChCl: glycerol in the molar ratio of 1:2, respectively at a specific temperature and water content range. The results revealed that conductivity of pure DESs were fitted to the Arrhenius equation, and the conductivity values of DESs diluted with 60% and 80% (v/v) water were similar and ranged between 2.13 and 220 mS/cm, with increased temperatures. The correlation between pH and surface tension of the three DESs with varying water content and temperature were consistent with the cubic model and viscosity were fitted to the Arrhenius equation. DES with varying water content and reaction temperature had effect on esterification conversion rate of lipase N435, and were fitted to the cubic model. Spearman correlation analysis found a correlation between viscosity and surface tension and conversion rates. The catalytic activity and viscosity, and surface tension in ChCl: urea system was well fitted (R-2>0.98). The fitting effect of catalytic activity and viscosity in ChCl: glycerol system, and the fitting effect of catalytic activity and surface tension in ChCl: ethylene glycol system were well (R-2>0.98). Catalytic activity and pH in three DESs system were not well fitted (R-2<0.78). The results of the study revealed that the use of equations and models to correlate DESs properties with catalyzed synthesis activity was effective and reliable. (C) 2020 Elsevier B.V. All rights reserved.