A highly parallel microfluidic droplet method enabling single-molecule counting for digital enzyme detection

Although digital detection of nucleic acids has been achieved by amplification of single templates in uniform microfluidic droplets and widely used for genetic analysis, droplet-based digital detection of proteins has rarely been reported, largely due to the lack of an efficient target amplification method for protein in droplets. Here, we report a key step towards digital detection of proteins using a highly parallel microfluidic droplet approach for single enzyme molecule detection in picoliter droplets via enzyme catalyzed signal amplification. An integrated microfluidic chip was designed for high throughput uniform droplet generation, monolayer droplet collection, incubation, detection, and release. Single β-galatosidase (β-Gal) molecules and the fluorogenic substrate fluorescein di-β-D-galactopyranoside were injected from two separated inlets to form uniform 20 μm droplets in fluorinated oil at a frequency of 6.6 kHz. About 200 000 droplets were captured as a monolayer in a capture well on-chip for subsequent imaging detection. A series of β-Gal solutions at different concentrations were analyzed at the single-molecule level. With no enzyme present, no droplets were found to fluoresce, while brightly fluorescent droplets were observed under single-enzyme molecule conditions. Droplet fluorescence intensity distribution analysis showed that the distribution of enzyme molecules under single-molecule conditions matched well with theoretical prediction, further proving the feasibility of detecting single enzyme molecules in emulsion droplets. Moreover, the population of fluorescent droplets increased as the β-Gal concentration increased. Based on a digital counting method, the measured concentrations of the enzyme were found to match well with input enzyme concentration, establishing the accuracy of the digital detection method for the quantification of β-Gal enzyme molecules. The capability of highly parallel detection of single enzyme molecules in uniform picoliter droplets paves the way to microdroplet based digital detection of proteins.     

论我国传统体育观念的自为性

中国“体育”观念的发展演变已经历了一个多世纪,由于受社会、经济、文化和历史条件的限制,以及体育概念本身意义的复杂性,体育观念长期以来仍处在自为阶段。其突出表现为体育中附带着和负荷着太多的政治、历史和文化方面的因素,注重体育的结果,体育功能单一,比较忽视体育的本体意义和精神。     

高校实践教学管理信息化理论与实践

当今,随着我国经济的快速发展,我国的高校教育发展事业进程也在快速前进,21世纪,是信息技术高速发展的时代,信息技术已被运用到生活中的各个角落,在高校实施教学管理信息化也是顺应了信息化时代的要求。     

Journal writing as a way to know culture: insights from a travel study abroad program

In this work, we explore journal writing as a way to come to know culture, particularly cultural phenomenon, vastly different from one’s own firmly held and enacted beliefs. In this research, we accept the premise that writing is a way of knowing and adopt journal writing as a tool through which students can explore the knowledge they have developed as a result of their academic travel study experiences, all being participants in the China Study Abroad Program. Narrative threads from numerous graduate students’ journals are seamed together through the use of narrative inquiry’s analytical tools. The narrative exemplars that were created reinforce the personal, social, and professional importance of creating a reflective writing space through which many expressions of culture and students’ reflective responses to them can be channeled in productive and potentially transformative ways.     

论中国古典戏剧滑稽扮相的起源与发展

滑稽扮相是中国古典戏剧常用的喜剧技巧,萌芽于周朝,出现了以特殊的身形来制造滑稽效果的侏儒;从汉代至宋金时期为发展期,借装扮特殊的身形及服饰化妆来制造滑稽效果的手法被运用于中国早期戏剧;元明时期为成熟期,元明戏曲在滑稽扮相上趋向于综合使用各种手法以形成整体的滑稽效果。     

云计算研究与应用现状综述

系统分析和总结了云计算的研究现状,展望了云计算良好的发展前景;通过比较分析不同的云计算定义,综合分析了云计算的特征,提出了云计算平台的体系结构及其主要服务形式;最后探讨了云计算的主要关键技术,并以交通运输行业为背景提出了交通运输云平台建设和发展的参考设计.     

多技术溢出渠道对我国高技术产业创新的影响分析

本文实证分析了包括FDI、进出口和公共R&D等国内外不同技术溢出渠道对中国高技术产业的专利创新和新产品创新绩效的影响,结果表明产业自身的研发投入是产业创新的基础;高校和科研院所的公共研发是影响我国高技术产业创新的关键因素;通过出口学习参与国际市场竞争是提升产业学习能力和创新能力的必经之路;FDI流入和技术引进没有给产业带来模仿创新和技术泄露。     

天然气产销一体化勘探开发特点与策略

在长期的天然气产销一体化过程中,天然气滚动勘探开发具有循序性、渐进性、不定性、灵活性的特点,这深深影响着天然气产销一体化的发展变化。分析了当前我国天然气工业正经历着历史性的大发展时期,如何抓住战略机会,实现企业增产增效,加强与发展天然气产销一体化,指出这就需要实施加快滚动勘探开发步伐、加大科技攻关力度、坚持科学发展观。这对紧跟天然气行业发展步伐,积极主动应对天然气行业产销变革具有一定参考意义。     

产品平台演进模式及动力机制研究

随着大规模定制、模块化成为产品开发和生产的主流模式,产品平台创新已成为了局限企业产品自主创新能力发展的瓶颈。掌握产品平台发展规律及其动力机制是企业实施产品平台创新的前提和基础。本文通过某铣床类平台、厦工轮装(轮式装载机)平台和NOKIA手机平台的案例分析,基于大规模定制程度提出了三种产品平台演进模式,进一步分析产品平台演进的内外动因和两者之间的适配关系,以及不适配性引起偏差形成产品平台矛盾问题,得出了产品平台内部创新力形成机制和产品平台演进驱动模型。