教学课程资源库 更多>>

关键词： DFT   TD-DFT   SERS   NCI   Artesunate  

摘要： Artesunate and its derivatives belong to a family of compounds that are highly effective against Malaria. This drug is active against several other conditions like neurodegerative diseases and cancer. The compound forms a metabolite dihydroartemisinine, which contain an endoperoxide bridge that is stimulated by heme iron leading to oxidative stress, protein and nudeic add synthesis inhibition, morphologic changes and reduced growth and survival of parasites. This manuscript examines the structure and conformational preferences of the compound and investigates the energy and reactivity descriptors using computational simulations. Studies indicates that the compound forms stable self-assemblies with graphene quantum dots and modified graphene quantum dots, where the more stable complex was formed with the modified system. This self-assembly formation leads to enhancement in Raman activity of the compound after complex formation, hence can be used an analytical tool for the detection of the compound in a mixture. Natural bond orbital analysis examines the various intramolecular electron delocalisations. This drug is found to be a nonlinear optically active compound with respect to standards materials like urea and paranitroacetanilide. We also report the non covalent interactions present in the molecule, reduced density gradient, Lapalcian electron density and local information entropy of the molecule. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Zantaz honey   Methyl syringate   Antiproliferative activity   Antioxidant activity  

摘要： Zantaz honey is a monofloral variety produced from the melliferous plant Bupleurum spinosum (Apiaceae), a shrub that grows mainly in the Atlas Moroccan Mountains. Determination of the polyphenol composition revealed that methyl syringate accounts for more than 50% of total polyphenols, which represents a very useful parameter for the characterization of this monofloral honey. Epicatechin, syringic acid and catechin are also abundant. Caco-2 and THP-1 cells were used for determination of antioxidant and antiproliferative activities in Zantaz honey, respectively. All six commercial samples that were used for these studies exhibited antioxidant activity and inhibited cell proliferation. Interestingly, these activities had a positive correlation mainly with the content in methyl syringate and gallic acid. The recognition of health promoting activities in Zantaz honey should increase its commercial value, which would have a positive economic impact on the poor rural communities of Morocco where it is produced.

关键词： Garlic (Allium sativum L.)   Polysaccharide   Three-phase partitioning   Gradient ethanol precipitation   Preparation   Characterization   Bioactivity  

摘要： In the present study, three-phase partitioning (TPP) coupled with gradient ethanol precipitation (GEP) was developed for the first time to extract and isolate polysaccharides (GPSs) from raw garlic (Album sativum L.) bulbs. Four kinds of fructose polymers, namely, GPS35, GPS50, GPS65, and GPS80, were obtained at the final ethanol precipitation concentrations of 35%, 50%, 65%, and 80% (v/v), respectively, and their physicochemical characteristics and in vitro biological activities were investigated. Results indicated that GPS80 had higher carbohydrate (86.68% +/- 0.90%) and uronic acid (12.89% +/- 0.09%) contents, lower weight-average molecular weight (8.93 x 10(3) Da), and looser surface morphology than the other three GPSs. Furthermore, among the four GPSs, GPS80 exhibited the strongest antioxidant capacities, inhibitory effects on a-amylase and aglycosidase, and nitric oxide stimulatory activity on RAW264.7 macrophage cells in vitro. Therefore, this study provides a simple and feasible technological strategy for producing bioactive polysaccharides from raw Allium vegetables.

关键词： 物理化学实验   云班课   开放性实验   翻转课堂  

摘要： 以云班课为教学平台,采用翻转课堂为主的教学模式开展物理化学开放性实验教学,详细介绍了开放性实验分层教学体系、实验教学内容、微课的设计方法和实践过程。实践结果表明,通过这些教学手段,教师能顺利地开展开放性实验教学,提升学生的学习兴趣和创新能力,同时也提高了实验室资源的利用率。

关键词： “双一流”建设   科研创新能力   物理化学实验   大学化学教育   实验教学  

摘要： 物理化学实验在大学化学教育、教学中的地位非常重要,在创建世界一流大学、一流学科等方面发挥着特殊的作用.辽宁师范大学物理化学实验教学团队不断探索,形成了多层次全开放的实验教学体系、科研课题式的小组实验模式,并将纵向、横向所得科研结果转换为实验教学内容,定期、不定期地开展前沿科研讲座,把前沿发展融合进课堂的同时,培养了学生的科研创新能力,从而为基础教育领域“高水平”化学教师及化学相关人才的培养贡献力量.

关键词： Cotton/halophytes inter cropping system   Suaeda salsa   Alfalfa   Soil salinization   Salt removal   Cotton yield  

摘要： Soil salinization has become a severe threat deteriorating soil quality and restricting sustainable agricultural development in arid and semi-arid areas. The objective of this study was therefore to propose a new cotton/ halophytes intercropping system [such as cotton/Suaeda salsa intercropping (CSSI) and cotton/alfalfa inter cropping (CAI) systems] to improve soil salinization and crop production based on the traditional monoculture cotton (MC). A three-year field experiment was conducted to explore the effects of the MC, CSSI, and CAI systems on soil salt accumulation, salt removal, soil physicochemical properties, root mass density, aboveground biomass, seed cotton yield, and irrigation water productivity (IWP). Experiment treatments consisted of three cropping systems: MC, CSSI, and CAI systems, respectively. All treatments were designed using a randomized complete block with three replications. The result indicated that the CSSI and CAI systems could decrease soil EC1:5, salt accumulation, bulk density, Na+ content, and pH in no mulch strips and increase salt removal, soil porosity, and organic carbon content compared with the MC system. Compared with the MC system, the CSSI system increased root mass density in 0-20 cm soil depth. No significant differences in seed cotton yield and IWP were found among the MC, CSSI, and CAI systems in 2014. However, total aboveground biomass, seed cotton yield, and IWP were significantly higher in the CSSI and CAI systems than that of the MC system in 2015 and 2016. This study suggested that the cotton/halophytes intercropping system showed greater salt removal and crop productivity than the MC system. Therefore, the CSSI and CAI systems should be recommended as a longterm agronomic remediation method for improving soil salinization and increasing cotton yield in the arid area of northwest China.

关键词： Soil organic carbon   Cation exchange capacity   Soil mineralogy   Soil structure  

摘要： The interactions of climatic and geochemical factors control soil organic carbon storage capacity and turnover. The comprehensive evaluation of the effect of long-term detritus manipulation on the soil organic carbon, soil-forming processes and the soil physical and chemical properties will help us better understand the carbon sequestration of forest soils. The long-term (19 years) effect of detrital input and removal treatments (DIRT) on physicochemical soil properties were investigated at a Central-European forest site (Sikfokut, Hungary). In contrast to the results of similar experiments in other parts of the world, the detritus input treatments affected the soil organic carbon and almost all of the soil physicochemical indicators for the upper 15 cm layer. Soil pH, potential acidity and base saturation decreased in the litter removal plots and increased in the detritus doubling treatments. A decrease in organic matter content in the litter removal plots explained the changes in bulk density, as the stability of aggregates also decreased with the decrease of exchangeable bases and organic colloids. In this respect, compared to the other DIRT sites and other similar experiments in the world, our experimental site is considered unique, as it has the highest clay content and the driest climate. We conclude that potential cation exchange capacity and base saturation (exch. Ca) play a fundamental role in predicting the occurrence of the carbon sequestration mechanisms. We suggest to include these parameters into current SOC models.

关键词： 物理化学   思政教育   教学改革   德育元素  

摘要： 以《物理化学》课程为例,介绍在当前工程教育背景下,德育与专业课教育有机融合的重要性。要利用好课堂这个渠道,将思政思想贯穿于整个课程教学过程,在为国家培养有文化的青年才俊的同时,也为社会主义事业培养合格建设者和可靠接班人。结合物理化学教学实践,提出了物理化学思政改革的具体策略,探讨物理化学课程中的思政无素,以供同行在思政教育方面参考。

关键词： Plant protein   Quinoa protein isolate   Drying methods   Physicochemical properties   Functional properties  

摘要： Quinoa protein possesses great amino acid profiles and can be a potential food ingredient with broad applications. The objective of this study was to investigate the effect of different drying methods, namely freeze drying, spray drying, and vacuum drying on the functional and physicochemical properties of quinoa protein isolate, e.g., morphology, amino acid composition, SDS-PAGE profile, sulfhydryl/disulfide content, secondary structure, surface hydrophobicity, and thermal stability. The freeze-dried protein exhibited the highest emulsification capacity and stability and oil binding capacity, which was contributed to its higher surface hydrophobicity, while the spray-dried sample had the highest solubility and water absorption capacity at pH 7. Gels (8%) prepared with the freeze-dried protein had higher elastic and viscous modulus than that from others. The freeze-dried protein had the highest maximal denaturation temperature but lowest enthalpy, which may be attributed to its higher amount of random coil but lower percent of regular alpha-helix and beta-sheet structures. Overall, quinoa protein isolate from different processing methods demonstrated distinct functional properties. This information will be useful to optimize quinoa protein production and benefit its applications.

关键词： Chitosan   Deep eutectic solvent (DES)   Choline chloride (ChCl)   Lactic acid (LA)   Mechanical properties   Food packaging  

摘要： In this work deep eutectic solvent (DES), based on the mixture of choline chloride and lactic acid, were suggested as chitosan films plasticizers. The molecular structure and properties of films obtained using chitosan, with different degree of deacetylation and 0-80 wt.% DES content (omega(DES)), were studied by means of FTIR spectroscopy, SEM and AFM microscopy (films' surface properties) together with optical characteristics, water vapor transmission rate (WVTR), water vapor permeability (WVP), tensile strength (TS) and elongation at break (E-b). Scanning electron micrographs revealed that all chitosan-DES films were smooth and uniform. DES significantly improves the film flexibility (E-b increases of ca. 160 % after incorporation of 80 wt.% DES), slightly decreases tensile strength and also improves antioxidative properties while simultaneously, increasing water vapor permeability (WVP). Films prepared in this study exhibit characteristics that qualify them for potential use as an active packaging material.