Quantitative detection of cells expressing BlaC using droplet-based microfluidics for use in the diagnosis of tuberculosis     

Fengjiao Lyu  Manqi Xu  Yunfeng Cheng  Jinghang Xie  Jianghong Rao  Sindy K. Y. Tang 《Biomicrofluidics》2015,9(4)

This paper describes a method for the quantitative detection of cells expressing BlaC, a β-lactamase naturally expressed by Mycobacterium tuberculosis, intended for the diagnosis of tuberculosis. The method is based on the compartmentalization of bacteria in picoliter droplets at limiting dilutions such that each drop contains one or no cells. The co-encapsulation of a fluorogenic substrate probe for BlaC allows the quantification of bacteria by enumerating the number of fluorescent drops. Quantification of 10 colony forming units per milliliter is demonstrated. Furthermore, the encapsulation of single cell in drops maintains the specificity of the detection scheme even when the concentration of bacteria that do not express BlaC exceeds that expressing BlaC by one million-fold.  相似文献   

Disrupting the wall accumulation of human sperm cells by artificial corrugation     

H. A. Guidobaldi  Y. Jeyaram  C. A. Condat  M. Oviedo  I. Berdakin  V. V. Moshchalkov  L. C. Giojalas  A. V. Silhanek  V. I. Marconi 《Biomicrofluidics》2015,9(2)

Many self-propelled microorganisms are attracted to surfaces. This makes their dynamics in restricted geometries very different from that observed in the bulk. Swimming along walls is beneficial for directing and sorting cells, but may be detrimental if homogeneous populations are desired, such as in counting microchambers. In this work, we characterize the motion of human sperm cells ∼60 μm long, strongly confined to ∼25 μm shallow chambers. We investigate the nature of the cell trajectories between the confining surfaces and their accumulation near the borders. Observed cell trajectories are composed of a succession of quasi-circular and quasi-linear segments. This suggests that the cells follow a path of intermittent trappings near the top and bottom surfaces separated by stretches of quasi-free motion in between the two surfaces, as confirmed by depth resolved confocal microscopy studies. We show that the introduction of artificial petal-shaped corrugation in the lateral boundaries removes the tendency of cells to accumulate near the borders, an effect which we hypothesize may be valuable for microfluidic applications in biomedicine.  相似文献   

Core-shell hydrogel beads with extracellular matrix for tumor spheroid formation     

L. Yu  S. M. Grist  S. S. Nasseri  E. Cheng  Y.-C. E. Hwang  C. Ni  K. C. Cheung 《Biomicrofluidics》2015,9(2)

Creating multicellular tumor spheroids is critical for characterizing anticancer treatments since they may provide a better model of the tumor than conventional monolayer culture. Moreover, tumor cell interaction with the extracellular matrix can determine cell organization and behavior. In this work, a microfluidic system was used to form cell-laden core-shell beads which incorporate elements of the extracellular matrix and support the formation of multicellular spheroids. The bead core (comprising a mixture of alginate, collagen, and reconstituted basement membrane, with gelation by temperature control) and shell (comprising alginate hydrogel, with gelation by ionic crosslinking) were simultaneously formed through flow focusing using a cooled flow path into the microfluidic chip. During droplet gelation, the alginate acts as a fast-gelling shell which aids in preventing droplet coalescence and in maintaining spherical droplet geometry during the slower gelation of the collagen and reconstituted basement membrane components as the beads warm up. After droplet gelation, the encapsulated MCF-7 cells proliferated to form uniform spheroids when the beads contained all three components: alginate, collagen, and reconstituted basement membrane. The dose-dependent response of the MCF-7 cell tumor spheroids to two anticancer drugs, docetaxel and tamoxifen, was compared to conventional monolayer culture.  相似文献   

Referee acknowledgment for 2014     

Hsueh-Chia Chang  Leslie Y. Yeo 《Biomicrofluidics》2015,9(1)

  相似文献   

题目：一种支持产品平台设计的多准则模块划分方法   总被引：2，自引：0，他引：2  

Wei WEI  Ang LIU  Stephen C.Y.LU  Thorsten WUEST 《浙江大学学报(A卷英文版)》2015,(1):1-10

目的：研究多准则约束下的产品模块划分方法,为企业建立稳健的模块化产品平台奠定基础。方法：采用改进的多目标进化算法对建立的多准则模块划分数学模型求解,并采用模糊集合评价机制进行最优解的寻取,得到基于多准则模块划分方法的产品模块划分结果。结论：通过改进的多目标进化算法求解多准则模块划分模型,能够得到有效支持产品平台设计的产品模块划分方案。通过与已有优化方法的比较验证了本文提出的多准则模块划分方法的优越性。  相似文献   

Relationship Reciprocation Modulates Resource Allocation in Adolescent Social Networks: Developmental Effects          下载免费PDF全文

Stephanie Burnett Heyes  Yeou‐Rong Jih  Per Block  Chii‐Fen Hiu  Emily A. Holmes  Jennifer Y. F. Lau 《Child development》2015,86(5):1489-1506

Adolescence is characterized as a period of social reorientation toward peer relationships, entailing the emergence of sophisticated social abilities. Two studies (Study 1: N = 42, ages 13–17; Study 2: N = 81, ages 13–16) investigated age group differences in the impact of relationship reciprocation within school‐based social networks on an experimental measure of cooperation behavior. Results suggest development between mid‐ and late adolescence in the extent to which reciprocation of social ties predicted resource allocation. With increasing age group, investment decisions increasingly reflected the degree to which peers reciprocated feelings of friendship. This result may reflect social‐cognitive development, which could facilitate the ability to navigate an increasingly complex social world in adolescence and promote positive and enduring relationships into adulthood.  相似文献   

论苏童笔下的“颂莲”式女性     

周茜  王艳芳 《乐山师范学院学报》2015,(7)

苏童是少数几个尤其擅长写女性的男性作家。他对女性的心理描写和细节把握都处理得恰到好处,非常自然。他笔下的女性一改过往的温柔善良、知书达理,相反的,大多都阴暗猥琐、粗俗野蛮、善于妒忌,非常具有特色,成为中国当代女性小说的独有景观。苏童的几个从女性视角描写的女主人公具有很多的共同特征,他将这些女性称为“颂莲”式女性。  相似文献   

Hands-On: Investigating the role of physical manipulatives in spatial training     

Katie A. Gilligan-Lee  Zachary C. K. Hawes  Ashley Y. Williams  Emily K. Farran  Kelly S. Mix 《Child development》2023,94(5):1205-1221

Studies show that spatial interventions lead to improvements in mathematics. However, outcomes vary based on whether physical manipulatives (embodied action) are used during training. This study compares the effects of embodied and non-embodied spatial interventions on spatial and mathematics outcomes. The study has a randomized, controlled, pre-post, follow-up, training design (N = 182; mean age 8 years; 49% female; 83.5% White). We show that both embodied and non-embodied spatial training approaches improve spatial skills compared to control. However, we conclude that embodied spatial training using physical manipulatives leads to larger, more consistent gains in mathematics and greater depth of spatial processing than non-embodied training. These findings highlight the potential of spatial activities, particularly those that use physical materials, for improving children's mathematics skills.  相似文献   

How do thinking styles and STEM attitudes have effects on computational thinking? A structural equation modeling analysis     

Haozhe Jiang  A. Y. M. Atiquil Islam  Xiaoqing Gu  Jia Guan 《科学教学研究杂志》2024,61(3):645-673

Computational thinking (CT) is vital for success in numerous domains. However, the nature, definition, and scope of CT are ill-defined, and research on how best to develop CT is very limited. This study focused on how thinking styles and STEM attitudes have effects on computational thinking. Using a proportionate stratified random sampling procedure, 1195 students from two universities were surveyed. A structural equation modeling analysis showed that students' thinking styles and STEM attitudes directly predicted their computational thinking skills and that thinking styles mediated the relationship between STEM attitudes and computational thinking skills. Thinking styles and STEM attitudes are strong predictors of CT skills. Based on the results, we recommended that the conceptualization of CT be broadened to reflect its trans-disciplinary nature within the context of STEM education. This study adds to the limited theoretical understanding of CT and CT-predictors in higher education, which has been studied much less than in K-12 education.  相似文献   

An evaluation framework for cross-lingual link discovery     

Ling-Xiang Tang  Shlomo Geva  Andrew Trotman  Yue Xu  Kelly Y. Itakura 《Information processing & management》2014

Cross-Lingual Link Discovery (CLLD) is a new problem in Information Retrieval. The aim is to automatically identify meaningful and relevant hypertext links between documents in different languages. This is particularly helpful in knowledge discovery if a multi-lingual knowledge base is sparse in one language or another, or the topical coverage in each language is different; such is the case with Wikipedia. Techniques for identifying new and topically relevant cross-lingual links are a current topic of interest at NTCIR where the CrossLink task has been running since the 2011 NTCIR-9. This paper presents the evaluation framework for benchmarking algorithms for cross-lingual link discovery evaluated in the context of NTCIR-9.  相似文献