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Puchberger-Enengl D Podszun S Heinz H Hermann C Vulto P Urban GA 《Biomicrofluidics》2011,5(4):044111-044111-10
In this contribution, we present a system for efficient preconcentration of pathogens without affecting their viability. Development of miniaturized molecular diagnostic kits requires concentration of the sample, molecule extraction, amplification, and detection. In consequence of low analyte concentrations in real-world samples, preconcentration is a critical step within this workflow. Bacteria and viruses exhibit a negative surface charge and thus can be electrophoretically captured from a continuous flow. The concept of phaseguides was applied to define gel membranes, which enable effective and reversible collection of the target species. E. coli of the strains XL1-blue and K12 were used to evaluate the performance of the device. By suppression of the electroosmotic flow both strains were captured with efficiencies of up to 99%. At a continuous flow of 15 μl/min concentration factors of 50.17 ± 2.23 and 47.36 ± 1.72 were achieved in less than 27 min for XL1-blue and K12, respectively. These results indicate that free flow electrophoresis enables efficient concentration of bacteria and the presented device can contribute to rapid analyses of swab-derived samples. 相似文献
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Sally Lubeck Patricia Jessup Mary deVries Jackie Post 《Early childhood research quarterly》2001,16(4):233
In this article, we draw on work in three Head Start programs over three years to consider how “culture” plays a role in program improvement. Through close attention to discourse we attempt to show how culture takes shape through dynamic interactions in particular contexts, constituting identities, structuring social relations, and privileging particular forms of knowledge. We argue for the importance of illuminating the forces that shape our lives and bringing our own ideologies to conscious awareness, in order to become actors in our social milieus. Articulation between general mandates and local needs and goals would then entail ongoing dialogue in a “culturally situated model of school/program effectiveness” (Fuller & Clarke, 1994, p. 121). 相似文献
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ABSTRACT At Eastern Michigan University, information about library resources and services for Extended Programs (off-campus and online) students was provided in a number of online locations and was sometimes inconsistent and difficult to manage. The library formed an internal task force to evaluate all of the library information and instructional materials provided to Extended Programs students. The task force consolidated key information in one location on the library Web site and collaborated with departments within the library and around campus to provide links from the relevant online locations. This case study describes how Google Analytics was used to assess the use of the revised library Web site and online instructional materials by Extended Programs students. The researchers describe examples of techniques for using Google Analytics and explain how the data collected was used to identify further enhancements to the information provided to Extended Programs students. 相似文献
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In the field of early childhood education, dominant discourse is premised on assumptions and values that privilege uniformity, generality, and even the “essential” nature of children and programs that should then be judged according to common criteria. In this article, we focus not on common factors that vary but on particular social practices that have very different meanings for people in two social settings (Taylor, 1979). Specifically, we describe how parent involvement- and parents themselves-were socially constructed within Head Start programs located in different communities, and we suggest how these social practices made particular forms of involvement possible and even necessary. We argue that discourses do not merely represent; they constitute, and different discourses construct both subjects and social relations in particular ways. Finally, we suggest how alternative ways of structuring knowledge and social practice in early childhood might become “communal tools” for exploring yet to be realized possibilities. 相似文献