The construction of an interfacial valve-based microfluidic chip for thermotaxis evaluation of human sperm     

Zhuoqi Li  Weiran Liu  Tian Qiu  Lan Xie  Weixing Chen  Ran Liu  Ying Lu  Keith Mitchelson  Jundong Wang  Jie Qiao  Jing Cheng 《Biomicrofluidics》2014,8(2)

Thermotaxis has been demonstrated to be an important criterion for sperm evaluation, yet clinical assessment of thermotaxis capacity is currently lacking. In this article, the on-chip thermotaxis evaluation of human sperm is presented for the first time using an interfacial valve-facilitated microfluidic device. The temperature gradient was established and accurately controlled by an external temperature gradient control system. The temperature gradient responsive sperm population was enriched into one of the branch channels with higher temperature setting and the non-responsive ones were evenly distributed into the two branch channels. We employed air-liquid interfacial valves to ensure stable isolation of the two branches, facilitating convenient manipulation of the entrapped sperm. With this device, thermotactic responses were observed in 5.7%-10.6% of the motile sperm moving through four temperature ranges (34.0-35.3 °C, 35.0-36.3 °C, 36.0-37.3 °C, and 37.0-38.3 °C, respectively). In conclusion, we have developed a new method for high throughput clinical evaluation of sperm thermotaxis and this method may allow other researchers to derive better IVF procedure.  相似文献   

Solution pH change in non-uniform alternating current electric fields at frequencies above the electrode charging frequency     

Ran An  Katherine Massa  David O. Wipf  Adrienne R. Minerick 《Biomicrofluidics》2014,8(6)

AC Faradaic reactions have been reported as a mechanism inducing non-ideal phenomena such as flow reversal and cell deformation in electrokinetic microfluidic systems. Prior published work described experiments in parallel electrode arrays below the electrode charging frequency (f_c), the frequency for electrical double layer charging at the electrode. However, 2D spatially non-uniform AC electric fields are required for applications such as in plane AC electroosmosis, AC electrothermal pumps, and dielectrophoresis. Many microscale experimental applications utilize AC frequencies around or above f_c. In this work, a pH sensitive fluorescein sodium salt dye was used to detect [H⁺] as an indicator of Faradaic reactions in aqueous solutions within non-uniform AC electric fields. Comparison experiments with (a) parallel (2D uniform fields) electrodes and (b) organic media were employed to deduce the electrode charging mechanism at 5 kHz (1.5f_c). Time dependency analysis illustrated that Faradaic reactions exist above the theoretically predicted electrode charging frequency. Spatial analysis showed [H⁺] varied spatially due to electric field non-uniformities and local pH changed at length scales greater than 50 μm away from the electrode surface. Thus, non-uniform AC fields yielded spatially varied pH gradients as a direct consequence of ion path length differences while uniform fields did not yield pH gradients; the latter is consistent with prior published data. Frequency dependence was examined from 5 kHz to 12 kHz at 5.5 V_pp potential, and voltage dependency was explored from 3.5 to 7.5 V_pp at 5 kHz. Results suggest that Faradaic reactions can still proceed within electrochemical systems in the absence of well-established electrical double layers. This work also illustrates that in microfluidic systems, spatial medium variations must be considered as a function of experiment time, initial medium conditions, electric signal potential, frequency, and spatial position.  相似文献   

浅析高校服务型学生干部队伍建设的路径     

李冉 《科教文汇》2014,(26):203-204

加强高校学生干部队伍建设是强化大学生思想政治教育的需要,是促进学校健康发展的需要。本文主要通过分析高校服务型学生干部队伍的重要作用、新形势下存在的问题,探讨出高校服务型学生干部队伍建设的方法,期望能够总结出一些学生干部队伍建设的新思路和创新路径。  相似文献   

环境约束下产品组合决策方法探析     

张秀敏  陶冉 《华东师范大学学报(哲学社会科学版)》2010,42(4):102-107

面对有限资源，企业如何在环境约束条件下尽可能减少污染、增加利润，寻求产品组合的优化，是企业环境管理中需要解决的问题。既定环境约束下产品组合决策的评价方法目前主要有两种，作业成本计算法（ＡＢＣ）与约束理论（ＴＯＣ）方法。这两种方法在基本假设、关注点以及约束等方面都存在着显著的差别。案例分析表明，ＴＯＣ方法所确定的产品组合排序，能够进一步增加利润，改善环境的效果更为持续，因而相对于ＡＢＣ方法而言，是一种更优的方法。  相似文献   

顾坤伯、孔仲起两位画师力作:《修海塘》     

文然 《文化交流》2005,(6)

今年11月25日,中国美术学院将举办顾坤伯教授诞辰100周年画展及座谈会,纪念这位卓越的美术教育家、中国山水画一代宗师。顾坤伯1905年生于无锡,21岁在上海美专毕业后留校任教,1957年经王个移、诸乐三、朱金楼推荐,由潘天寿院长特聘到浙江美术学院(今中国美术学院)执教。他以深厚的基本功和对传统的深入理解,逐渐形成了清雅俊逸的风格和高超的笔墨技法,堪为画坛风范。这幅画,是顾坤伯先生与其入室弟子孔仲起1958年的合作。画面生动,韵味悠长,风貌极具时代特征。此画曾一度流失,后孔仲起教授设法以大画换回,珍藏于室,日前展示给笔者激赏,相互…  相似文献   

对体育科技期刊青年编辑知识结构现状及影响因素的探讨     

冉强辉 《体育科学》1993,13(3):36-38

本文通过文献资料、调查统计等研究方法,探析了我国体育科技期刊青年编辑的知识结构现状及影响因素,并就其知识结构的构建要素,从实际需求和理论依据上进行论述。  相似文献   

QFD在机械类高素质应用创新型人才培养中的应用   总被引：2，自引：0，他引：2  

刘英  许延飞  黄冉 《高等工程教育研究》2011,(2):124-128

本文将质量功能配置(QFD)原理成功运用在高等院校机械类高素质应用创新人才培养过程中.以重庆大学机械设计制造及其自动化专业人才培养体系为研究对象,以学生和企业需求为出发点,利用QFD瀑布式分解模型,对教学设计(规划)、教学运行、教学控制等阶段进行质量功能配置,构建人才培养质量屋,规划专业培养方案,取得可喜的成果.本文还...  相似文献   

教育舆情研究:从兴起到有效的路径探索     

张天雪  张冉 《清华大学教育研究》2011,32(5)

教育舆情研究已由萌芽阶段进入到兴起阶段,但规范的教育舆情研究尚未形成。教育舆情研究要从研究主体、研究对象和研究手段等方面加以规范,规范的教育舆情研究会提升舆情效度。教育舆情的有效性来自于信息采集和舆情分析两个环节,需要专业的研究主体和研究手段,逐步形成相应的研究范式。这是教育政策决策的需要,也是教育治理过程中关注民生,体恤草根意愿的必然选择。  相似文献   

大学生求职资源动员行为的结构与测量——基于北京高校毕业生的实证研究     

张天舒  卞冉 《清华大学教育研究》2011,32(6)

本文依据北京13所不同层级高校1341名毕业生的实证调研数据,运用主成分分析法与结构方程模型比较,从资源动员视角分析了大学生求职行为的结构特征.研究发现,大学生求职行为的结构由四因素构成;中国大学生动员所属高校就业资源,是其重要的求职行为特征.  相似文献   

民办高等学校核心竞争力评价指标体系研究     

王文彬  许冉 《黑龙江教育学院学报》2011,30(10):20-22

近年来,民办高校发展迅速,在激烈的竞争中保持持续的竞争优势对民办高校非常重要。从民办高等学校核心竞争力内涵出发,依据客观公正、适用性等原则,提出建立民办高等学校的核心竞争力水平评价指标体系,并对指标体系的合理性进行了详细的阐述和分析,以期促进民办高校形成核心竞争力,并持续发展。  相似文献