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Matthew J. Kennedy Harold D. Ladouceur Tiffany Moeller Dickson Kirui Carl A. Batt 《Biomicrofluidics》2012,6(4)
The present work describes the operation and simulation of a microfluidic laminar-flow mixer. Diffusive mixing takes place between a core solution containing lipids in ethanol and a sheath solution containing aqueous buffer, leading to self assembly of liposomes. Present device architecture hydrodynamically focuses the lipid solution into a cylindrical core positioned at the center of a microfluidic channel of 125 × 125-μm2 cross-section. Use of the device produces liposomes in the size range of 100–300 nm, with larger liposomes forming at greater ionic strength in the sheath solution and at lower lipid concentration in the core solution. Finite element simulations compute the concentration distributions of solutes at axial distances of greater than 100 channel widths. These simulations reduce computation time and enable computation at long axial distances by utilizing long hexahedral elements in the axial flow region and fine tetrahedral elements in the hydrodynamic focusing region. Present meshing technique is generally useful for simulation of long microfluidic channels and is fully implementable using comsol Multiphysics. Confocal microscopy provides experimental validation of the simulations using fluorescent solutions containing fluorescein or enhanced green fluorescent protein. 相似文献
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Douglas A. Golick Tiffany M. Heng-Moss Allen L. Steckelberg David. W. Brooks Leon G. Higley David Fowler 《Journal of Science Education and Technology》2013,22(4):509-521
The purpose of the study was to determine whether undergraduate students receiving web-based instruction based on traditional, key character, or classification instruction differed in their performance of insect identification tasks. All groups showed a significant improvement in insect identifications on pre- and post-two-dimensional picture specimen quizzes. The study also determined student performance on insect identification tasks was not as good as for family-level identification as compared to broader insect orders and arthropod classification identification tasks. Finally, students erred significantly more by misidentification than misspelling specimen names on prepared specimen quizzes. Results of this study support that short web-based insect identification exercises can improve insect identification performance. Also included is a discussion of how these results can be used in teaching and future research on biological identification. 相似文献
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Marcia A. Roman Rosemarye T. Taylor Debbie Hahs-Vaughn 《Community College Journal of Research & Practice》2013,37(5):386-401
Institutional and student level data from the Florida Community Colleges were examined to explore the Retention Index of the Community College Survey of Student Engagement (CCSSE). A simple correlation and regression analysis was conducted to determine if the CCSSE Retention Index could be used to predict the institutional retention rate calculated for the state accountability measure. Student level data were used with a nested ANOVA to examine if there were mean differences in the CCSSE Retention Index scores of males and females of different racial groups when accounting for the potential influence of the institution attended. Mean differences were examined since differences in retention rates of these groups have been documented. 相似文献
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Seventy-six children ages 3 to 5 were individually read two storybooks that had been specially formatted to contain salient printed words within the text, and illustrations and text on left or right-facing pages. The reader pointed to each word while reading to half of the children. After each book, children were asked to recognize elements of the illustrations and the specially formatted text elements from among a set of foils. Videotaped sessions were coded for the time children spent looking toward the pages with print versus illustrations. Analyses showed that the percentage of time looking at print was less than 2% in the no-pointing condition but increased with age. Pointing to the words increased print-looking time for all age groups and print target recognition for 4-year-olds. After controlling for receptive vocabulary, visual memory, and maturation associated with these scores, emergent orthography and letter-word identification predicted time looking at print and recognition of the print elements. 相似文献
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John C. Teleha Iyanna Sims Octavious Spruill Arneice Bowen Tiffany Russell Nina Exner 《Public Services Quarterly》2017,13(3):139-151
Academic libraries are spending considerable time and study on redesigning spaces. The use of technology is often an important part of these redesigned spaces. The space redesign goals at F.D. Bluford Library focus on creating open, activity-promoting, colorful spaces that are designed to be attractive to students. The goals also focus on implementing hybrid spaces that allow students to work alone or in groups, with support for mobile technologies like laptops or tablets. The space redesign goals focus on upgrading the quality of desktops available but reducing the number of desktops. This study examines the question “Does our library renovation significantly change computer use in the redesigned area?” Key findings include that, in defiance of expectations, there is no significant decrease in desktop usage despite the decreased number of computers. However, findings show there is a significant difference in tablet use, despite tablet-friendly spaces and charging options. Surprisingly, our students use fewer tablets. Laptop usage shows no significant difference. In summary, our research shows desktop computing—especially high-quality desktop computing—appears to still have a role in academic libraries even in the mobile technology age. 相似文献
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This case study research reports on elementary (grade 8) and secondary school (grade 9) teachers’ participation in job-embedded, professional learning and engagement in collaborative inquiry. Teachers constructed an inquiry-oriented media literacy unit following the collaborative inquiry model. The current study sought to investigate how collaborative inquiry influenced their self-efficacy in literacy instruction, instructional and assessment practices. Qualitative data sources included researchers’ anecdotal notes, teacher interviews, and professional learning blog conversations. Inductive analyses of the data generated six major themes comprising enhancements to teachers’ literacy instructional and assessment practices, which were evident in their adoption of the backward-design model, use of success criteria, and greater emphasis on diagnostic and formative assessment. With respect to teachers’ self-efficacy, data analyses also revealed increased levels of intrinsic motivation, professional satisfaction, and reflective practice. This study provides evidence for the transformative potential and characteristics of school-based teacher collaborative inquiry and the resultant impacts on teacher learning. 相似文献
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Bo Yang Guo-qiang Liao Xiao-fei Wen Wei-hua Chen Sheng Cheng Jens-Uwe Stolzenburg Roman Ganzer Jochen Neuhaus 《Journal of Zhejiang University. Science. B》2017,18(11):921-933
Prostate cancer (PCa) is the second most common male cancer worldwide and the fifth leading cause of death from cancer in men. Early detection and risk stratification is the most effective way to improve the survival of PCa patients. Current PCa biomarkers lack sufficient sensitivity and specificity to cancer. Metabolite biomarkers are evolving as a new diagnostic tool. This review is aimed to evaluate the potential of metabolite biomarkers for early detection, risk assessment, and monitoring of PCa. Of the 154 identified publications, 27 and 38 were original papers on urine and serum metabolomics, respectively. Nuclear magnetic resonance (NMR) is a promising method for measuring concentrations of metabolites in complex samples with good reproducibility, high sensitivity, and simple sample processing. Especially urine-based NMR metabolomics has the potential to be a cost-efficient method for the early detection of PCa, risk stratification, and monitoring treatment efficacy. 相似文献