排序方式: 共有81条查询结果,搜索用时 15 毫秒
41.
Guillaume Mottet Karla Perez-Toralla Ezgi Tulukcuoglu Francois-Clement Bidard Jean-Yves Pierga Irena Draskovic Arturo Londono-Vallejo Stephanie Descroix Laurent Malaquin Jean Louis Viovy 《Biomicrofluidics》2014,8(2)
We present a low cost microfluidic chip integrating 3D micro-chambers for the capture and the
analysis of cells. This device has a simple design and a small footprint. It allows the
implementation of standard biological protocols in a chip format with low volume consumption. The
manufacturing process relies on hot-embossing of cyclo olefin copolymer, allowing the development of
a low cost and robust device. A 3D design of microchannels was used to induce high flow velocity
contrasts in the device and provide a selective immobilization. In narrow distribution channels, the
liquid velocity induces a shear stress that overcomes adhesion forces and prevents cell
immobilization or clogging. In large 3D chambers, the liquid velocity drops down below the threshold
for cell attachment. The devices can be operated in a large range of input pressures and can even be
handled manually using simple syringe or micropipette. Even at high flow injection rates, the 3D
structures protect the captured cell from shear stress. To validate the performances of our device,
we implemented immuno-fluorescence labeling and Fluorescence in Situ Hybridization
(FISH) analysis on cancer cell lines and on a patient pleural effusion sample. FISH is a Food and
Drug Administration approved cancer diagnostic technique that provides quantitative information
about gene and chromosome aberration at the single cell level. It is usually considered as a long
and fastidious test in medical diagnosis. This process can be easily implanted in our platform, and
high resolution fluorescence imaging can be performed with reduced time and computer intensiveness.
These results demonstrate the potential of this chip as a low cost, robust, and versatile tool
adapted to complex and demanding protocols for medical diagnosis. 相似文献
42.
Maryse Bianco Pascal Bressoux Anne-Lise Doyen Eric Lambert Laurent Lima Catherine Pellenq 《Scientific Studies of Reading》2013,17(3):211-246
A sample of 1,273 4-year-old children were followed for 3 years. The children participated in 1 of 2 comprehension training programs, or in a phonological awareness training program. The comprehension programs explored the possibility of improving young children's oral comprehension in an educational setting. The first focused on the component skills of comprehension; the second involved storybook reading. Phonological awareness and oral language comprehension skills were measured repeatedly in the course of the study. The data were analyzed using multilevel growth-curve models. The results showed that it is possible to improve oral comprehension if the training focuses on its component skills and extends over 2 semesters. When these conditions were met, training effects still existed 9 months after the program had ended. Finally, phonological training improved phonological awareness but not comprehension, and comprehension-skill training improved oral comprehension but not phonological awareness. 相似文献
43.
Brun Laurent Dompnier Benoit Pansu Pascal 《European Journal of Psychology of Education - EJPE》2022,37(1):185-206
European Journal of Psychology of Education - In educational contexts, interpersonal attributional theory (Weiner, 2019) posits that teachers’ beliefs about the causes underlying their... 相似文献
44.
AbstractThe aim was to assess the technical variability of a new wrist-worn accelerometer under controlled conditions with a shaker device and during normal daily physical activities (PAs). In the first experiment, 10 wrist-worn accelerometers (Vivago® Wellness, Paris, France) were attached to the shaker device. Variability was tested at five shaking frequencies (1.1, 2.1, 3.1, 4.1, and 10 Hz) for 10 min at each frequency. In the second experiment, 21 participants wore wrist-worn accelerometers and performed six consecutive 10-min periods of activity at increasing levels of intensity from sedentary to vigorous. Results from the first experiment show a modest inter- and intra-instrument reliability at low frequencies and that reliability improved as frequency increased. The inter-instrument coefficient of variation (CV) was 2.6–18.3%. The intra-instrument CV was 4.1–23.2%. Variability was similar in the second experiment with a CV inversely related to PA intensity. The inter- and intra-instrument CV varied from 24.2% and 19.9% for sedentary activities to 3.7% and 4.3% for vigorous PA, respectively. Results suggest that reliability was higher at high intensities, corresponding to moderate and vigorous PA, intensities generally recommended for public health purposes. 相似文献
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46.
AbstractWe present adaptable activities for models of drug movement in the human body – pharmacokinetics – that motivate the learning of ordinary differential equations with an interdisciplinary topic. Specifically, we model aspirin, caffeine, and digoxin. We discuss the pedagogy of guiding students to understand, develop, and analyze models, progressing in complexity to a system of differential equations. We investigate the effects of parameter values that distinguish various health levels, and dosing that may have toxic effects. Our assignments include modeling in a student-centered, active, and increasingly inquiry-oriented setting through which the mathematics and biology inform and reinforce each other. We include supplemental information regarding inquiry methods, student learning outcomes, a student’s commentary about our activities, and support through mathematical communities such as POGIL and SIMIODE. 相似文献
47.
Delphine Chadefaux Guillaume Rao Jean-Loïc Le Carrou Eric Berton Laurent Vigouroux 《Journal of sports sciences》2017,35(12):1155-1164
The aim of this article is to characterise the extent to which the dynamic behaviour of a tennis racket is dependent on its mechanical characteristics and the modulation of the player’s grip force. This problem is addressed through steps involving both experiment and modelling. The first step was a free boundary condition modal analysis on five commercial rackets. Operational modal analyses were carried out under “slight”, “medium” and “strong” grip force conditions. Modal frequencies and damping factors were then obtained using a high-resolution method. Results indicated that the dynamic behaviour of a racket is not only determined by its mechanical characteristics, but is also highly dependent on the player’s grip force. Depending on the grip force intensity, the first two bending modes and the first torsional mode frequencies respectively decreased and increased while damping factors increased. The second step considered the design of a phenomenological hand-gripped racket model. This model is fruitful in that it easily predicts the potential variations in a racket’s dynamic behaviour according to the player’s grip force. These results provide a new perspective on the player/racket interaction optimisation by revealing how grip force can drive racket dynamic behaviour, and hence underlining the necessity of taking the player into account in the racket design process. 相似文献
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49.
Heidemarie K. Laurent Leslie D. Leve Jenae M. Neiderhiser Misaki N. Natsuaki Daniel S. Shaw Philip A. Fisher Kristine Marceau Gordon T. Harold David Reiss 《Child development》2013,84(2):528-542
Child hypothalamic pituitary adrenal (HPA) activity was investigated as a moderator of parental depressive symptom effects on child behavior in an adoption sample (n = 210 families). Adoptive parents' depressive symptoms and child internalizing and externalizing were assessed at 18, 27, and 54 months, and child morning and evening HPA activity measured through salivary cortisol at 54 months. Children's daily cortisol levels and day‐to‐day variability were tested as moderators of longitudinal associations between parent and child symptoms at within‐ and between‐family levels. Mothers' symptoms related directly to child internalizing, but child evening cortisol moderated effects of fathers' symptoms on internalizing, and of both parents' symptoms on externalizing. Different paths of within‐family risk dynamics versus between‐family risk synergy were found for internalizing versus externalizing outcomes. 相似文献
50.
C. Matthew Laurent Michael C. Meyers Clay A. Robinson Lorna R. Strong Charles Chase Beelee Goodwin 《Journal of sports sciences》2013,31(7):709-716
Abstract The aim of this study was to assess and compare the validity of the portable VmaxST telemetry metabolic measurement device with that of a standard measurement system (Vmax29). Thirty asymptomatic, moderately active males provided written, informed consent and completed two maximal graded treadmill exercise tests (Bruce) using the VmaxST and the Vmax29 metabolic measurement systems. Tests were performed in random order on separate days to obtain peak values for time to exhaustion, heart rate, systolic and diastolic blood pressure, oxygen consumption ([Vdot]O2), carbon dioxide production ([Vdot]CO2), ventilation ([Vdot] E), and respiratory exchange ratio (RER). Multivariate analysis of variance revealed no significant main effect (P = 0.88) between the two systems across any variable, suggesting similar measurement capabilities between the two systems. Linear regression analyses revealed moderate to high coefficients of determination for [Vdot]O2 (r 2 = 0.99), [Vdot]CO2 (r 2 = 0.99), [Vdot] E (r 2 = 0.99), and RER (r 2 = 0.89). Furthermore, Bland-Altman analyses demonstrated that the VmaxST yielded similar values to the Vmax29, suggesting good agreement between the two systems. Agreement was confirmed when the differences between the methods resulted in a small range as identified by the 95% limits of agreement. Findings from the current study confirm that the VmaxST is a valid device for measuring metabolic and physiological variables during exercise within a controlled laboratory setting. 相似文献