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101.
Harisha Ramachandraiah Sahar Ardabili Asim M. Faridi Jesper Gantelius Jacob M. Kowalewski Gustaf M?rtensson Aman Russom 《Biomicrofluidics》2014,8(3)
Passive particle focusing based on inertial microfluidics was recently introduced as a
high-throughput alternative to active focusing methods that require an external force field to
manipulate particles. In inertial microfluidics, dominant inertial forces cause particles to move
across streamlines and occupy equilibrium positions along the faces of walls in flows through
straight micro channels. In this study, we systematically analyzed the addition of secondary Dean
forces by introducing curvature and show how randomly distributed particles entering a simple
u-shaped curved channel are focused to a fixed lateral position exiting the curvature. We found the
lateral particle focusing position to be fixed and largely independent of radius of curvature and
whether particles entering the curvature are pre-focused (at equilibrium) or randomly distributed.
Unlike focusing in straight channels, where focusing typically is limited to channel cross-sections
in the range of particle size to create single focusing point, we report here particle focusing in a
large cross-section area (channel aspect ratio 1:10). Furthermore, we describe a simple u-shaped
curved channel, with single inlet and four outlets, for filtration applications. We demonstrate
continuous focusing and filtration of 10 μm particles (with >90% filtration
efficiency) from a suspension mixture at throughputs several orders of magnitude higher than flow
through straight channels (volume flow rate of 4.25 ml/min). Finally, as an example of high
throughput cell processing application, white blood cells were continuously processed with a
filtration efficiency of 78% with maintained high viability. We expect the study will aid in the
fundamental understanding of flow through curved channels and open the door for the development of a
whole set of bio-analytical applications. 相似文献
102.
In this paper, we estimate the impact of receiving an NIH postdoctoral training grant on subsequent publications and citations. Our sample consists of all applications for NIH postdoctoral training grants (unsuccessful as well as successful) from 1980 to 2000. Both ordinary least squares and regression discontinuity estimates show that receipt of an NIH postdoctoral fellowship leads to about one additional publication over the next five years, which reflects a 20% increase in research productivity. 相似文献
103.
Jacob E. Barkley Ellen Glickman Curtis Fennell Mallory Kobak Megan Frank Gregory Farnell 《Journal of sports sciences》2019,37(7):735-740
Low-cost physical activity monitors may provide a more accurate measure of physical activity than subjective methods (e.g., self-report) while being less costly than research-grade accelerometers. The present study assessed the validity of a low-cost monitor (Movband 2) to estimate physical activity behavior/intensity. Participants (N = 23, n = 16 female, BMI = 22.9 ± 4.0 kg/m2, age = 21.9 ± 1.6 years) completed four, five-minute treadmill stages (2.0, 3.0, 4.0, 5.0 MPH) while wearing both the Movband and the previously-validated Actigraph monitor. Oxygen consumption (VO2) was recorded during each stage (Laboratory assessment). A subset (n = 15, n = 10 female, BMI = 22.2 ± 3.2 kg/m2, age = 21.5 ± 0.8 years) of these participants then wore the two accelerometers for three days (Free-living assessment). During the Laboratory assessment there were strong, significant (r = 0.94, p ≤ 0.001) relationships between Movband and Actigraph counts and VO2. During Free-living assessment there was also a strong, significant (r = 0.97, p < 0.001) correlation between Movband and Actigraph counts. The low-cost, Movband accelerometer appears to provide a valid assessment of physical activity behavior/intensity. 相似文献
104.
Arthur Louis Odom Jacob M. Marszalek Elizabeth R. Stoddard Jerzy M. Wrobel 《International Journal of Science Education》2013,35(17):2351-2374
The purpose of this study was to examine the association of middle school student science achievement and attitudes toward science with student-reported frequency of using computers to learn science and other classroom practices. Baseline comparison data were collected on the frequency of student-centred teaching practices (e.g. the use of group experiments during science class) and traditional teaching practices (e.g. having students copy notes during science class) to learn science. The student sample was composed of 294 seventh-grade students enrolled in middle school science. Multiple regression was used to investigate the association of attitudes toward science, student-centred teaching practices, computer usage, and traditional teaching practices with science achievement. Both attitudes toward science and student-centred teaching practices were positively associated with science achievement, and student-centred teaching practice was positively associated with attitude toward science. Computer usage was found to have a negative association with student achievement, which was moderated by traditional teaching practices. 相似文献
105.
The concept of intrinsic motivation lies at the heart of the user engagement created by digital games. Yet despite this, educational software has traditionally attempted to harness games as extrinsic motivation by using them as a sugar coating for learning content. This article tests the concept of intrinsic integration as a way of creating a more productive relationship between educational games and their learning content. Two studies assessed this approach by designing and evaluating an educational game called Zombie Division to teach mathematics to 7- to 11-year-olds. Study 1 examined the learning gains of 58 children who played either the intrinsic, extrinsic, or control variants of Zombie Division for 2 hr, supported by their classroom teacher. Study 2 compared time on task for the intrinsic and extrinsic variants of the game when 16 children had free choice of which game to play. The results showed that children learned more from the intrinsic version of the game under fixed time limits and spent 7 times longer playing it in free-time situations. Together, these studies offer evidence for the genuine value of an intrinsic approach for creating effective educational games. The theoretical and commercial implications of these findings are discussed. 相似文献
106.
107.
Jacob S. Golub 《Journal of Jewish Education》2013,79(1):49-55
Israeli film and television have risen to international prominence, presenting compelling and complicating perspectives. Simultaneously, Web 2.0 technologies have accelerated the spread and immediacy of digital media. Following the work of Holtz (2003) and Levisohn (2010) in developing orientations for teaching Bible and Rabbinic Literature, this article develops a menu of media studies orientations for teaching Israel to Americans. It explores distinctive aspects of media studies, the relevance to Israel education of the work of Marland (1968a, 1968b), and applies the orientations through case studies of the Israeli television series Be-Tipul and Hatufim and their American adaptations, In Treatment and Homeland. 相似文献
108.
INTRODUCTION Video packets are transmitted over the Internet using a best-effort service. Therefore, a large number of simultaneous video streams or cross traffic arriving at a network node (e.g. a multimedia gateway) may sometimes exceed the node’s forwarding capacity, i.e., the incoming data rate may exceed the outgoing data rate at the node. In this paper, we consider a scenario where M streaming videos and N conversa- tional videos pass through a network node with lim- ited forwardi… 相似文献
109.
110.