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31.
Sara Baratchi Francisco J. Tovar-Lopez Khashayar Khoshmanesh Megan S. Grace William Darby Juhura Almazi Arnan Mitchell Peter McIntyre 《Biomicrofluidics》2014,8(4)
Shear stress is the major mechanical force applied on vascular endothelial cells by blood flow, and is a crucial factor in normal vascular physiology and in the development of some vascular pathologies. The exact mechanisms of cellular mechano-transduction in mammalian cells and tissues have not yet been elucidated, but it is known that mechanically sensitive receptors and ion channels play a crucial role. This paper describes the use of a novel and efficient microfluidic device to study mechanically-sensitive receptors and ion channels in vitro, which has three independent channels from which recordings can be made and has a small surface area such that fewer cells are required than for conventional flow chambers. The contoured channels of the device enabled examination of a range of shear stresses in one field of view, which is not possible with parallel plate flow chambers and other previously used devices, where one level of flow-induced shear stress is produced per fixed flow-rate. We exposed bovine aortic endothelial cells to different levels of shear stress, and measured the resulting change in intracellular calcium levels ([Ca2+]i) using the fluorescent calcium sensitive dye Fluo-4AM. Shear stress caused an elevation of [Ca2+]i that was proportional to the level of shear experienced. The response was temperature dependant such that at lower temperatures more shear stress was required to elicit a given level of calcium signal and the magnitude of influx was reduced. We demonstrated that shear stress-induced elevations in [Ca2+]i are largely due to calcium influx through the transient receptor potential vanilloid type 4 ion channel. 相似文献
32.
Javier Noya Salces Pedro M. Gómez-Carmona Diego Moliner-Urdiales Manuel Sillero-Quintana 《Journal of sports sciences》2014,32(13):1263-1270
AbstractThe aim was to examine the injuries sustained by Spanish football players in the First Division and to compare injury-related variables in the context of both competition and training. The injury data were prospectively collected from 16 teams (427 players) using a specific web-based survey during the 2008/2009 season. A total of 1293 injuries were identified (145 were recurring injuries). The overall injury incidence was 5.65 injuries per 1000 h of exposure. Injuries were much more common during competition than during training (43.53 vs. 3.55 injuries per 1000 h of exposure, P < 0.05). Most of the injuries (89.6%) involved the lower extremities, and overuse (65.7%) was the main cause. Muscle and tendon injuries were the most common types of injury (53.8%) among the players. The incidence of training injuries was greater during the pre-season and tended to decrease throughout the season, while the incidence of competition injuries increased throughout the season (all P < 0.05). In conclusion, the results of this study suggest the need for injury prevention protocols in the First Division of the Spanish Football League to reduce the number of overuse injuries in the muscles and tendons in the lower extremities. In addition, special attention should be paid during the pre-season and the competitive phase II (the last four months of the season) in order to prevent training and competition injuries, respectively. 相似文献
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The aim of this research has been to test the efficacy of an intervention programme on lexical-semantic problems in children with Specific Language Impairment (SLI). The sample consisted of 34 children diagnosed with SLI and 34 children with typical language development, all enrolled in different schools on the island of Tenerife (Canary Islands, Spain). For the selection of the sample, CELF-3, Peabody, ITPA Auditory Association and Visual Association subtests and the K-BIT IQ tests were used. The intervention programme consisted of 72 sessions of 30 minutes each, using noun and action naming activities along with conversation and categorization tasks in order to increase vocabulary and improve lexical semantic competence. Significant results were achieved in aspects related to the acquisition of vocabulary as well as in lexical semantics or related terms. The educational implications are clear insofar as lexical-semantic aspects are key in terms of activating other linguistic components and in improving the academic progress of SLI students. 相似文献
36.
Lorena Olvera Moreno 《American journal of sexuality education》2017,12(3):337-341
The Atlas of Erotic Anatomy and Arousal is online video education that explores sexual pleasure and sexual anatomy from a sex positive perspective. Written and presented by a sex educator and therapist, Cyndi Darnell, this video is an excellent resource for adult individuals interested in learning about their bodies and having fulfilling sexual experiences with their partners. The video series provides scientifically accurate and pleasure-based information about the anatomy of the vulva, the penis, and the anus, and the physiology of orgasm and ejaculation, in an entertaining manner. 相似文献
37.
This study documents the reliability and validity of a new infant-toddler authentic assessment, the Learning Through Relating Child Assets Record (LTR-CAR), and its feasibility of use by infant-toddler caregivers in an Early Head Start program. In a sample of 136 children, results indicated a strong internal structure of the LTR-CAR as evidenced by high internal consistency within age bands, expected performance in terms of the order of difficulty of items, and expected performance relative to the chronological ages of children. Moreover, the LTR-CAR accounted for a statistically significant amount of unique variance (between 6 and 26%), over and above age and gender, in six out of eight regressions predicting criterion measures. Given the increasing numbers of infants and toddlers in non-parental care, the need for authentic assessment as a tool to plan meaningful learning opportunities, as well as the lack of evidence-based authentic assessment options at the infant-toddler level, the LTR-CAR may provide a viable option for the field. 相似文献
38.
José L. Arco-Tirado Francisco D. Fernández-Martín Juan-Miguel Fernández-Balboa 《Higher Education》2011,62(6):773-788
The purposes of this study were, on one had, to determine the impact of a peer tutoring program on preventing academic failure
and dropouts among first-year students (N = 100), from Civil Engineering, Economics, Pharmacy, and Chemical Engineering careers; while, on the other hand, to identify
the potential benefits of such tutoring program on the cognitive and metacognitive learning strategies and social skills of
student mentors in their last year of studies or already in a postgraduate program (N = 41) at the University of Granada (Spain). After building and selecting the measurement instruments necessary to gather
demographic and academic relevant information on both samples, and assigning first-year students to either an experimental
or control group, the intervention consisted of ten 90-min tutoring sessions during the first semester lead by student tutors
who, in turn, had undergone four 3-h training sessions on tutoring contents like planning and time management, cognitive and
metacognitive learning strategies, motivational strategies and the use of materials designed ad hoc for this program. The results show differences in favour of the treatment group on grade point average, performance rate,
success rate and learning strategies and, also, statistically significant pre-post differences for the tutors on learning
strategies and social skills. 相似文献
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Sidney Roberto Carvalho Ubirajara Franco Moreno 《Journal of The Franklin Institute》2021,358(9):5039-5072
In distributed and cooperative systems, the network structure is determinant to the success of the strategy adopted to solve complex tasks. Those systems are primarily governed by consensus protocols whose convergence is intrinsically dependent on the network topology. Most of the consensus algorithms deal with continuous values and perform average-based strategies to reach cohesion over the exchanged information. However, many problems demand distributed consensus over countable values, that cannot be handled by traditional protocols. In such a context, this work presents an approach based on semidefinite programming to design the optimal weights of a network adjacency matrix, in order to control the convergence of a distributed random consensus protocol for variables at the discrete-space domain, based on the voter model. As a second contribution, this work uses Markov theory and the biological inspiration of epidemics to find out a dynamical spreading model that can predict the information diffusion over this discrete consensus protocol. Also, convergence properties and equilibrium points of the proposed model are presented regarding the network topology. Finally, extensive numerical simulations evaluate the effectiveness of the proposed consensus algorithm, its spreading model, and the approach for optimal weight design. 相似文献