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关键词： Granule shells component   Fraction   Molecular properties  

摘要： The physicochemical properties of corn starch (CS) and a component of granule shells (C-s) obtained through a granule shells separation process, were studied. The shells separation was accurately visualized and confirmed by SEM and TEM images. Both CS and C-s contained three components (amylopectin, intermediate fraction and amylose) with a M-w ranging from 4.11 x 10(7) to 11.42 x 10(7) g/mol. The amylose content of CS and C-s was in the following order: C-s-83 > CS > C-s-69 > C-s-76. There were no significant differences observed between CS and C-s-83 for the dynamic modulus, apparent viscosity, peak viscosity and final viscosity, while C-s-69 and C-s-76 exhibited a decreasing trend. The DSC results revealed that the transition temperatures of CS were significantly higher than those of C-s. There was an obvious decrease in the thermal degradation onset temperature (T-o) for the treated samples (CS:312.26 degrees C, C-s-69: 311.87 degrees C, C-s-76: 307.62 degrees C and C-s-83: 307.11 degrees C). The crystalline patterns of CS were converted from A-type to C-type during the granule shells separation process. The relative crystallinities of C-s were significantly lower than that of CS (26.87%). The FTIR results showed that intramolecular and intermolecular hydrogen-bonding (O-H) of C-s were weakened after shells separation treatment. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Starch   taioba   Cassava   Physicochemical properties   Saccharification   Bioethanol  

摘要： Starch is an important raw material in the fermentation industry for producing ethanol, which can then be used as renewable biofuel or as a basis for food, drink and pharmaceutical uses. Many tropical starch-producing plants are poorly exploited. Taioba (Xanthosoma sagittifolium) is a subsistence agriculture plant that has high starch content in its tubers but there have been few scientific studies for ethanol production to the present. The objective of this work was to evaluate the structural and physicochemical characteristics of taioba starch and its potential for ethanol production by comparing it to cassava (Manihot esculenta) starch, a well-known and commercially exploited plant. The starch content in the taioba and cassava were 65 and 80 % (DW), which had an amylose content of 21.80 and 23.65 % (DW), respectively. However, taioba starch had a lower proportion of short branched chains (DP 6 -12), a higher proportion of intermediate branched chains (DP 13 - 24 and 25 - 36) of amylopectin (which are associated to the long term-retrogradation), smaller granule sizes and more densely packed and ordered crystals than cassava starch. It also had higher gelatinization temperatures and enthalpy change, lower peak and breaking viscosities, and a higher final viscosity compared to cassava starch. The hydrolysis (liquefaction and saccharification) reached 52 % and 50 % after 24 h, for cassava and taioba respectively. Maximum ethanol productions were 56 and 48 g/L, productivities were 0.67 and 0.56 g/L/h, yields were 0.49 and 0.46 and fermentation efficiencies were 96 and 90 %, for the cassava and taioba starches respectively. This study has improved understanding of the properties of taioba starch, as well its potential as a raw material for ethanol production.

关键词： COVID-19   Tocilizumab   Critical quality attributes   IV and SC medicines  

摘要： COVID-19,a disease caused by the novel coronavirus SARS-Co V-2,has produced a serious emergency for global public health,placing enormous stress on national health systems in many *** studies suggest that cytokine storms(interleukins)may play an important role in severe cases of *** key inflammatory factors in cytokine release syndrome(CRS)could therefore be of great value in reducing the mortality ***(TCZ)in its intravenous(IV)form of administration-Ro Actemra?20 mg/m L(Roche)-is indicated for treatment of severe CRS *** investigations have concluded that inhibition of IL-6 with TCZ appears to be efficacious and safe,with several ongoing clinical *** has led to a huge increase in demand for IV TCZ for treating severe COVID-19 patients in hospitals,which has resulted in drug ***,we present a comparability study assessing the main critical physicochemical attributes of TCZ solutions used for infusion,at 6 mg/m L and 4 mg/m L,prepared from Ro Actemra?20 mg/m L(IV form)and from Ro Actemra?162 mg(0.9 m L solution pre-filled syringe,subcutaneous(SC)form),to evaluate the use of the latter for preparing clinical solutions required for IV administration,so that in a situation of shortage of the IV medicine,the SC form could be used to prepare the solutions for IV delivery of *** is important to remember that during the current pandemic all the medicines are used off-label,since none of them has yet been approved for the treatment of COVID-19.

关键词： 物理化学   线上课堂   探索   实践  

摘要： 一场疫情让面对面的课堂变成直播课,线上教学成为师生共同的选择。直播课上,部分学生很难集中注意力。如何让学生听懂直播课,记住所学知识,使直播课产生持久的影响力?安阳工学院化学与环境工程专业物理化学线上课程在直播过程通过更新教育理念,变革教学方法,使用多维度考核方法,成功地开展了物理化学课程在线教学的探索和实践,在优化教学资源的同时,实现有效的在线学习考核,取得了良好的教学效果。

关键词： 物理化学   线上教学   教学模式   师生互动  

摘要： 受新型冠状病毒疫情影响,各高校纷纷转变教学模式,探索线上教学。北京航空航天大学物理化学课程采用线上录课教学方式,经过近两个月的教学实践,我们在实践中不断总结,不断改革教学设计,加强师生互动,并提出了后续线上教学的改进措施,总结了目前课程线上教学的优缺点,希望可以随着线上教学的不断深入,能够结合物理化学课程特点,设计更好的教学方案,引导学生发挥主观能动性,调动学生学习热情,取得良好的教学效果,并形成特色的教学方案。

关键词： 物理化学实验   设计型实验   纳米Ag  

摘要： 为加强实验课程的综合性和实践性,将纳米Ag的制备及表征作为设计型实验引入物理化学实验教学,实验以教师引导式教学和学生自主学习为主。该实验涉及金属纳米材料的制备、表征及应用等方面。以硝酸银为银源,在教师给定范围内自行选择还原剂和添加剂,采用液相还原法或溶剂热法制备纳米Ag。利用扫描电镜或透射电镜等手段进行表征,通过Nano Measure或Image-Pro Plus等手段进行数据处理。实验将物理化学的基础理论知识与学科前沿相结合,将纳米科技引入本科教育,培养了学生的创新意识和综合解决问题的能力。

关键词： 问题探究式教学   稀溶液依数性   物理化学   教学效果  

摘要： 稀溶液依数性是物理化学中的重要内容,理想稀溶液中溶剂的化学势表达式μA(1)=μ*A(1)+RT ln xA是[1]造成溶液中溶剂的蒸气压下降、凝固点降低、沸点升高和渗透压的根本原因。学生很难通过公式去掌握教学内容,使得教学效果不佳。采用问题探究式教学方法,通过学生对身边生活环境的观察,引导、启发学生思考、讨论,增强学生学习的兴趣,提高物理化学课堂教学效果,从授人鱼的"知识传授"到授人渔的"能力培养"转变。

关键词： Composite gel microparticles   Pectin   Alginate  

摘要： Composite gel microparticles based on alginate and callus culture pectins with low and high degrees of methylesterification or apple pectin were produced. By varying the chemical composition of the pectic samples and the ratio of alginate to pectin, the gel strength, morphology, and swelling properties of composite microparticles can be altered. The inclusion of increasing concentrations of alginate in gel formulations promoted an increase in the microparticle gel strength and the formation of a smoother surface microrelief independently of the pectin chemical composition. Microparticles based on the pectin with a low degree of methylesterification (DM) and a higher concentration of alginate exhibited an increased swelling degree in the simulated digestive fluids. Microparticles based on the pectin with high DM and low alginate concentration were destroyed in the simulated intestinal fluid within 1 h due to the low Ca2+ content, gel strength, and grooved and rough surface of these microparticles. An increase in alginate concentration of gel formulations based on pectin with high DM led to increased stability of the microparticles in the simulated intestinal and colonic fluids due to increased Ca2+ content, microparticle gel strength and degree of crosslinking. (C) 2020 Elsevier B.V. All rights reserved.

关键词： 物理化学   公式   记忆方法  

摘要： 提出了一些物理化学公式的记忆方法:只记反常公式法、过程分类法、同形对比法、“桥梁”公式法、交换位置法,希望通过抓住不同公式的特点,帮助学生记忆公式。