A validated stability-indicating LC method for the separation of enantiomer and potential impurities of Linezolid using polar organic mode

Although a number of methods are available for evaluating Linezolid and its possible impurities, a common method for separation if its potential impurities, degradants and enantiomer in a single method with good efficiency remain unavailable. With the objective of developing an advanced method with shorter runtimes, a simple, precise, accurate stability-indicating LC method was developed for the determination of purity of Linezolid drug substance and drug products in bulk samples and pharmaceutical dosage forms in the presence of its impurities and degradation products. This method is capable of separating all the related substances of Linezolid along with the chiral impurity. This method can also be used for the estimation of assay of Linezolid in drug substance as well as in drug product. The method was developed using Chiralpak IA (250 mm 4.6 mm, 5 mm) column. A mixture of acetonitrile, ethanol, n-butyl amine and trifluoro acetic acid in 96:4:0.10:0.16 (v/v/v/v) ratio was used as a mobile phase. The eluted compounds were monitored at 254 nm. Linezolid was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. The degradation products were well resolved from main peak and its impurities, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantification, precision, linearity, accuracy, robustness and system suitability.

Effect of aggregation on thermally activated delayed fluorescence and ultralong organic phosphorescence:QM/MM study

Aggregation-induced thermally activated delayed fluorescence(TADF)phenomena have attracted extensive attention recently.In this paper,several theoretical models including monomer,dimer,and complex are used for the explanation of the luminescent properties of(R)-5-(9H-carbazol-9-yl)-2-(1,2,3,4-tetrahydronaphthalen-1-yl)isoindoline-1,3-dione((R)-ImNCz),which was recently reported[Chemical Engineering Journal 418129167(2021)].The polarizable continuum model(PCM)and the combined quantum mechanics and molecular mechanics(QM/MM)method are adopted in simulation of the property of the molecule in the gas phase,solvated in acetonitrile and in aggregation states.It is found that large spin–orbit coupling(SOC)constants and a smaller energy gap between the first singlet excited state and the first triplet excited state(△E_(st))in prism-like single crystals(SC_(p)-form)are responsible for the TADF of(R)-lmNCz,while no TADF is found in block-like single crystals(SC_(b)-form)with a larger △E_(st).The multiple ultralong phosphorescence(UOP)peaks in the spectrum are of complex origins,and they are related not only to ImNCz but also to a minor amount of impurities(ImNBd)in the crystal prepared in the laboratory.The dimer has similar phosphorescence emission wavelengths to the(R)-lmNCz-SC_(p) monomers.The complex composed of(R)-lmNCz and(R)-lmNBd contributes to the phosphorescent emission peak at about 600 nm,and the phosphorescent emission peak at about 650 nm is generated by(R)-lmNBd.This indicates that the impurity could also contribute to emission in molecular crystals.The present calculations clarify the relationship between the molecular aggregation and the light-emitting properties of the TADF emitters and will therefore be helpful for the design of potentially more useful TADF emitters.

Examining micro-cavity parameters of top emission organic light-emitting diode with low-order resonant modes

Emission characteristics of top emitting organic light-emitting devices （TOLEDs） with Ag as reflective anode, Al/Ag as semitransparent cathode and 90 160 nm [N-（1-naphthyl）-N-phenyl-amino] biphenyl/tris-（8-hydroxy quinoline） aluminum （NPB/Alq3） sandwiched in the electrodes are examined. The electroluminescence （EL） spectra of the TOLEDs are simulated based on the Fabry-Perot cavity theory. And the resonant modes in cavity structure of TOLEDs is discussed and clarified which can accurately describe the work principle of the devices. A fairly good match between calculated values and experimental data is achieved at different emission colors from bluish green to orange.

Organic/ Inorganic Occurrence of Metallic Elements of the Black Shale-Hosted Baiguoyuan Silver-Vanadium Deposit in Xingshan, Hubei

: By means of kerogen purification, the proton induced X-ray emission (PIXE) and instrumental neutron activation analysis (INAA), the authors have studied the organic/inorganic occurrence modes of the metallic elements of the Baiguoyuan silver-vanadium deposit hosted in black shale in Hubei Province, China. The result shows that Au, Hg and Ta have a strong tendency to occur organically, with more than 70% of these elements being associated organically. Se, Ga, Ag and Hf are partly associated with organic matter, with more than 20% of them occurring organically. Compared with the above elements, Zn, Cu, As and Sb are weakly associated organically, and tend to be enriched in kerogen. However, Mn, Th, U, V, Co, Cr, AI, Fe and Sc usually occur inorganically. Of the rare earth elements (REE), La, Ce, Tb, Dy, Yb and Lu have stronger ability to be associated with organic matter than Sm and Eu.

Failure behavior of protective organic coatings under corrosive conditions

Recent research activities on the formation of micro-defects and porosity in organic coatings were reviewed. The mechanisms of aggressive ionic conduction through organic coatings were analyzed. The micro-mechanisms for the failure behavior of coatings under corrosive environments were discussed in detail. These mechanisms included blistering (i. e. osmotic blistering, anodic blistering and cathodic blistering) in the coating, wet-adhesion loss at the substrate/coating interface, cathodic delamination of coating from the substrate. Based on these researches, it was found that the failure behavior of organic coatings is closely related to the micro-defects in coatings, regardless of the failure mode. Additionally, the general failure mode of a coating system was proposed to interpret the failure behavior of organic in corrosion environments. The topics discussed can provide some insights into the development of a methodology for designing fail-safe coating systems.

Study on Organization and Operation Mode of SMT-MG

SNIT-MG is a typical application of grid in electric product manufacturing.The organization and operation mode are hey problems in SMT-MG.In this paper,SMT-MG is taken as research object.Its mesh three-dimensional matrix orga- nization mode is presented.Meanwhile from operation foundation,process,environment and target four aspects,operation prin- ciples are explored.Operation mechanisms of SMT-MG such as adaptive evolution,PUSH/PULL driving,cooperation and game,feedback,regulation/control,coordination,impetus mechanism and so on are studied.Finally,the operation flow of SMT-MG is introduced.

Growth and characterization of AlN epilayers using pulsed metal organic chemical vapor deposition

We report the growth of Al N epilayers on c-plane sapphire substrates by pulsed metal organic chemical vapor deposition（MOCVD）. The sources of trimethylaluminium（TMAl） and ammonia were pulse introduced into the reactor to avoid the occurrence of the parasitic reaction. Through adjusting the duty cycle ratio of TMAl to ammonia from 0.8 to 3.0, the growth rate of Al N epilayers could be controlled in the range of 0.24 m/h to 0.93 m/h. The high-resolution x-ray diffraction（HRXRD） measurement showed that the full width at half maximum（FWHM） of the（0002） and（10-12） reflections for a sample would be 194 arcsec and 421 arcsec, respectively. The step-flow growth mode was observed in the sample with the atomic level flat surface steps, in which a root-mean-square（RMS） roughness was lower to 0.2 nm as tested by atomic force microscope（AFM）. The growth process of Al N epilayers was discussed in terms of crystalline quality, surface morphology,and residual stress.

Problems in the Innovation of Tobacco Production Organization Mode in Sichuan Province and Recommendations

We summarize the main forms of tobacco production organization in Sichuan Province,including traditional peasant households,large scale growers,family farms,tobacco farmers' associations,and specialized tobacco cooperatives.In the process of innovation of production organization mode,some problems are pointed out,such as lack of management talents and long-term incentive mechanism,lack of standardization in operation,bottleneck in land and financing,low economic benefits of cooperatives,and difficulty in protecting farmers' interests and rights.We put forth the following recommendations for advancing the innovation of tobacco production organization mode in Sichuan Province:forming the longterm mechanism for supporting the innovation of production organization forms;standardizing the operation of the specialized cooperative organizations;strengthening personnel training,and establishing tobacco farmers' principal position;expanding cooperative economic production organizations,and achieving moderate concentration of land size;strengthening information services,to boost the development of cooperative production organizations.

Comparison and Selection of Organization Modes in Edible Fungus Industry of Shandong Province

China is the largest producer and exporter of edible fungus in the world,and Shandong is the largest producer of edible fungus in China.This study is intended to select suitable organization mode for edible fungus industry of Shandong Province.On the basis of types and characteristics of existing edible fungus production modes in China,it is concluded that Shandong Province should take following measures:(1)giving priority to development of integrated organization mode;(2)steadily promoting park and factory mode in economically developed regions;(3)developing circular agriculture in regions with solid foundation of agriculture and animal husbandry.Finally,it puts forward following recommendations:(1)speeding up construction of standardization and information platform for edible fungus industry;(2)improving quality of personnel engaged in edible fungus industry;(3)bringing into play driving effect of leading enterprises;(4)developing and introducing deep processing enterprises.

Technology Innovation Mode of Agricultural Leading Enterprise——Based on the Virtual Organization Mode

Based on the definition of technology innovation of agricultural leading enterprises by domestic and foreign experts and scholars,technology innovation of agricultural enterprises is a process of new market increment,which uses new knowledge,technology,process and production mode,produces new products,offers new services and realizes commercialization. Characteristics of agricultural technology innovation are introduced,such as obvious regionality,relatively high risk,long-term periodicity and public attribute. Predicament for technology innovation of leading enterprises is analyzed,such as technical constraints,financial constraints and personnel constraints. Technological Innovation Mode can be classified into three modes of independent innovation,imitative innovation and cooperative innovation by the method of technology innovation. Among them,since there are some defects in the technology innovation process,independent innovation and imitative innovation are generally not used for the innovation of agricultural enterprises. Cooperative Innovation Mode can rely on foreign aid,can realize complementary advantages and achievement sharing,and can be widely applied in the agricultural innovation enterprise. Virtual organization in cooperation innovation mode is described,which makes up for technology,capital and human resources barriers in the process of agricultural enterprise innovation. Therefore,this mode is popular among the agricultural innovation enterprise.

On the Operation and Organization Mode of the Enterprise＇s E-commerce

The E-business organization of enterprise comes into being due to the demand of era. With the development of the society, it has been developing from H type to U Mode, to the shape of matrix and then to the shape of the network. The evolution of these modes is derived from the necessity to serve customers and society better. This is the current E-business organization mode.

Contrastive Analysis of Chinese and English Modes of Thinking and Its Effects on Discourse Organization in EFL Writing

Based on the contrastive analysis of Chinese and English modes of thinking, this essay analyzes from two aspects the effects of their discrepancies on the discourse organization of Chinese students ' English writing, then explains the fundamental reason for these effects and proposes that teachers should impart to students knowledge about the differences between Chinese and English mode of thinking so that Chinese students can be better helped to organize their compositions on the English discourse patterns and compose idiomatic English writings.

Present Situation and Development Mode of Chinese Farmers' Cooperative Organizations

In developed countries,the typical modes of farmers' cooperative organizations are " German mode", " Japan and South Korea mode" and " American mode". The development of farmers' cooperative organizations in China is the product of need and being needed,with low level of specialization,systematism and industrialization. However,Chinese farmers' cooperative organizations have the advantages of diversification,full supporting and great opportunities of Internet economy and e-commerce environment. Based on that,this paper puts forward the " Chinese mode" for the development of farmers' cooperative organizations in China in the future,that is,the main body of innovation and entrepreneurship will unite,and the other entities of production and industry will follow them.

基于“雨课堂”的植物生理学混合式教学设计与探索

随着多媒体工具和网络覆盖普及,基于互联网的在线教育愈加便捷,但其优势并未在高校的课程教学中得到体现和充分应用。该文针对植物生理学的学科特点和教学现状,充分利用线上教学资源,针对性地选择教学内容和方法,以学生为主体、教师为主导,基于“雨课堂”等教学平台进行线上线下混合式教学模式初探,以期利用有限的学时和丰富的线上教学资源,整合线上和线下教学的优势,通过有效的管理方式组织实施,为深化信息化教学改革、提高植物生理学的教学效果奠定基础。

基于“四个面向”的高校“有组织科研”范式构建--一个单案例研究

当今世界正经历百年未有之大变局,世界各国科技竞争加剧,科技创新成为各国博弈的主战场。我国在基础研究、关键核心技术等领域正在遭受西方发达国家的围堵。高校作为基础研究主力军和重大科技突破策源地,传统科研范式在响应国家重大需求方面存在原始创新能力薄弱、科技成果转化率低、协同创新能力不足等问题。持续增大的外部压力、创新高风险与高投入使得“有组织科研”成为当前我国高校提升创新效能的重要选择,也是高校深度融入国家创新体系的重要举措。阐述“四个面向”和“有组织科研”的内涵,梳理“四个面向”与“有组织科研”、“有组织科研”与自由探索的关系,从高校传统科研范式亟待解决的问题入手,构建基于“四个面向”的高校“有组织科研”范式,对重庆大学“有组织科研”实施路径与成效进行解析,验证理论的科学性与适用性。

面向贯通式项目制教学的虚拟教研室组织模式实践

贯通式项目制教学模式是新工科背景下的工程教育新模式,贯穿大学本科四年,通过在做中学的实践,培养学生综合运用知识的能力和解决问题的能力。面向贯通式项目制教学的虚拟教研室是跨学科、跨专业、跨课程的校企联合的新型基层教学组织,是教学研究改革专题虚拟教研室。遵循教学问题导向原则,探讨实践了虚拟教研室的人员组成和人员管理模式。实践了充分运用信息技术,突破时空限制,开展高效便捷、形式多样、线上线下结合的教研新模式,提出了基于国家虚拟教研室平台的贯通项目制教学优质教学资源和教师培训的建设方案,为新型基层教学组织建设提供了一种新思路。

加拿大科技“超级集群”计划建设及启示

结合加拿大近年经济形势、研发投入、政策支撑等方面,分析加拿大提出“超级集群”计划的背景,同时介绍“超级集群”遴选过程,分析组建构成,调研近年来数字技术超级集群、蛋白质产业超级集群、下一代制造业超级集群、人工智能驱动的供应链超级集群、海洋超级集群5个超级集群建设运行成效。作为加拿大政府从国家层面设计的科技战略,加拿大政府重视产学研结合与多学科融合,通过超级集群构建科技创新生态系统,对我国创新科研组织方式具有较强借鉴意义,据此可以从强化战略目标、聚焦投入领域,打造战略科技力量、推动各主体协同创新,加强政策引导支持、营造创新生态环境等方面提升我国科研管理水平。

有机化学课程线上线下混合式教学模式的探索与实践

文章探索了有机化学课程线上线下混合式教学模式,通过课程教学内容与思政元素的有机结合及教学内容的模块化建设,助力教学的实施。以OBE理念为指导,线下教学过程通过思政引领和案例剖析,培养学生勤于思考、勇于探索的科学精神和社会责任意识。线上教学对线下教学起到辅助、补充和拓展作用,能够使学生巩固所学理论基础知识,极大地提升学生分析和解决问题的能力。线上与线下相结合的考核模式、教师评价与学生互评相结合的评价方式,能够有效反映课程目标的达成情况,为教学方法和教学手段的优化提供依据。

NASA重大项目预研管理过程研究——以韦布望远镜为例

做好重大科技项目的组织管理是实现抢占科技制高点目标的重要前提条件。本文以美国国家航空航天局(National Aeronautics and Space Administration,NASA)系列管理文件为分析对象,剖析其项目组织管理模式,并以投资近百亿美元、持续数十年的詹姆斯·韦布太空望远镜项目为例,对NASA重大项目预研管理过程进行分析。NASA将项目按照成本、风险、是否属于优先事项等分为3个类别进行管理,项目生命周期可以分为从“A前”(pre-A)到A、B直至F共7个阶段。韦布望远镜从1995年进入NASA的“A前阶段”,由3家单位独立开展概念研究;1999年7月从3家单位中遴选2家开始“A阶段”研究;2002年9月正式选择1家单位牵头开展“B阶段”研究。可供我国借鉴之处包括:项目组织方应发挥好“总体”角色,凝聚多方资源、提供长期稳定支持;新项目的酝酿需充分利用前期项目的科学、技术、管理人才基础;可利用“赛马制”等分阶段推进重大项目的实施,以降低不确定性和决策风险等。

过硫酸盐活化方法研究进展

综述了国内外过硫酸盐活化方法的研究进展,分析了物理活化方法、化学活化方法、联合活化方法产生氧化性自由基的机理,总结了不同活化方法的优缺点和常见应用场景以及利用活化的过硫酸盐降解有机污染物的研究现状。在分析总结过硫酸盐活化方法存在问题的基础上,提出过硫酸盐活化方法的进一步研究设想,以期为过硫酸盐修复实际污染土壤提供技术支撑。