1,554 research outputs found

    The Effect Of Intermittent Cooling On Simulated Basketball Game Performance

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    Context: Hyperthermia is induced during prolonged exercise which promotes fatigue and a decline in performance. Basketball athletes have trouble preventing an onset of hyperthermia; thus, cryotherapy is applied intermittently to combat the negative effects. Objective: To determine, (1) effect intermittent cooling has on simulated basketball performance, perceived exertion and perceived recovery; and (2) change in performance while applying two different forms of intermittent cooling during the Basketball Specific Fatigue Protocol (BSFP). Design: Crossover study design. Setting: Indoor collegiate basketball court. Patients or Other Participants: Sixteen competitively trained recreational basketball athletes (15 males, 1 female; age = 21.1 Ā± 1.2 yr). Main Outcome Measures: Participants completed 3 trials of the BSFP. Between quarters, intermittent cooling was applied for 5-minutes to the lower extremity using either a phase changing material (PCM), wetted ice (WI) or received no treatment (control). Change in countermovement jump height (Ī”CMJ), 10m sprint time (Ī”ST), heart rate (Ī”HR), ratings of perceived exertion (RPE) and perceived recovery score (PRS) were recorded each quarter. Results: PRS found to significantly increase starting quarter 2 (Q2), (7.0 Ā± 2.0, p = 0.02), with significantly higher PRS at Q2 using the PCM (7.5 Ā± 2.0, p \u3c 0.01). HR and ST saw significant change between quarters (Ī”HR: Q1 = 81.8 Ā± 2.6 bpm, p \u3c 0.01; Ī”ST: Q1 to Q4 (- 0.2 Ā± 0.1 s, p = 0.02), Q2 to Q4 (- 0.1 Ā± 0.0 s, p = 0.03), but not between conditions (Ī”HR: p = 0.51, Ī”ST: p = 0.33). RPE significantly increased each quarter until the completion of the simulated game (p Conclusions: Intermittent cooling, applied to the lower extremity via PCM, can increase perceived recovery through the first half of simulated basketball game performance

    Evidence of Deep Water Penetration in Silica during Stress Corrosion Fracture

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    We measure the thickness of the heavy water layer trapped under the stress corrosion fracture surface of silica using neutron reflectivity experiments. We show that the penetration depth is 65ā€“85ā€‰Ć…, suggesting the presence of a damaged zone of ~100ā€‰Ć… extending ahead of the crack tip during its propagation. This estimate of the size of the damaged zone is compatible with other recent results

    A modeling approach of the relationship between nitrous oxide fluxes from soils and the water-filled pore space

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    International audienceNitrous oxide (N2O) fluxes can increase significantly following small increases in soil water-filled pore space (WFPS). Thus, it is essential to improve our knowledge of this crucial relationship to better model N2O emissions by soils. We studied how much the addition of a gas transport and a gasā€“liquid equilibrium module to the model of N2O emissions NOE could improve simulation results. A sensitivity analysis of the modified model (NOEGTE: gas transport and equilibrium) was first performed, and then the model was tested with published data of a wettingā€“drying experiment. Simulated N2O fluxes plotted against WFPS appeared to be bell-shaped during the 7 days simulated, combining the effects of the low N2O production for WFPS 0.95. The WFPS generating the maximum simulated N2O fluxes shifted with time, from 0.76 after 12 h, to 0.79 after 168 h, because of an increase over time of the gas concentration gradient between the soil surface and the atmosphere. NOEGTE appeared able to capture the pattern of N2O emissions monitored in the experimental data. In particular, N2O peaks during drying were well reproduced in terms of timing, but their magnitudes were often overestimated. They were attributed to the increasing gas diffusivity and N2O exchanges from the liquid phase to the gaseous phase

    Diabetes mortality and trends before 25 years of age: an analysis of the Global Burden of Disease Study 2019

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    Background:Ā Diabetes, particularly type 1 diabetes, at younger ages can be a largely preventable cause of death with the correct health care and services. We aimed to evaluate diabetes mortality and trends at ages younger than 25 years globally using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. Methods:Ā We used estimates of GBD 2019 to calculate international diabetes mortality at ages younger than 25 years in 1990 and 2019. Data sources for causes of death were obtained from vital registration systems, verbal autopsies, and other surveillance systems for 1990ā€“2019. We estimated death rates for each location using the GBD Cause of Death Ensemble model. We analysed the association of age-standardised death rates per 100ā€‰000 population with the Socio-demographic Index (SDI) and a measure of universal health coverage (UHC) and described the variability within SDI quintiles. We present estimates with their 95% uncertainty intervals. Findings:Ā In 2019, 16ā€‰300 (95% uncertainty interval 14ā€‰200 to 18ā€‰900) global deaths due to diabetes (type 1 and 2 combined) occurred in people younger than 25 years and 73Ā·7% (68Ā·3 to 77Ā·4) were classified as due to type 1 diabetes. The age-standardised death rate was 0Ā·50 (0Ā·44 to 0Ā·58) per 100ā€‰000 population, and 15 900 (97Ā·5%) of these deaths occurred in low to high-middle SDI countries. The rate was 0Ā·13 (0Ā·12 to 0Ā·14) per 100ā€‰000 population in the high SDI quintile, 0Ā·60 (0Ā·51 to 0Ā·70) per 100ā€‰000 population in the low-middle SDI quintile, and 0Ā·71 (0Ā·60 to 0Ā·86) per 100ā€‰000 population in the low SDI quintile. Within SDI quintiles, we observed large variability in rates across countries, in part explained by the extent of UHC (r2=0Ā·62). From 1990 to 2019, age-standardised death rates decreased globally by 17Ā·0% (āˆ’28Ā·4 to āˆ’2Ā·9) for all diabetes, and by 21Ā·0% (ā€“33Ā·0 to āˆ’5Ā·9) when considering only type 1 diabetes. However, the low SDI quintile had the lowest decline for both all diabetes (āˆ’13Ā·6% [ā€“28Ā·4 to 3Ā·4]) and for type 1 diabetes (āˆ’13Ā·6% [ā€“29Ā·3 to 8Ā·9]). Interpretation:Ā Decreasing diabetes mortality at ages younger than 25 years remains an important challenge, especially in low and low-middle SDI countries. Inadequate diagnosis and treatment of diabetes is likely to be major contributor to these early deaths, highlighting the urgent need to provide better access to insulin and basic diabetes education and care. This mortality metric, derived from readily available and frequently updated GBD data, can help to monitor preventable diabetes-related deaths over time globally, aligned with the UN's Sustainable Development Targets, and serve as an indicator of the adequacy of basic diabetes care for type 1 and type 2 diabetes across nations. Funding:Ā  Bill & Melinda Gates Foundation

    Synaptophysin Is Required for Synaptobrevin Retrieval during Synaptic Vesicle Endocytosis

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    The integral synaptic vesicle (SV) protein synaptophysin forms approximately 10% of total SV protein content, but has no known function in SV physiology. Synaptobrevin (sybII) is another abundant integral SV protein with an essential role in SV exocytosis. Synaptophysin and sybII form a complex in nerve terminals, suggesting this interaction may have a key role in presynaptic function. To determine how synaptophysin controls sybII traffic in nerve terminals, we used a combination of optical imaging techniques in cultures derived from synaptophysin knockout mice. We show that synaptophysin is specifically required for the retrieval of the pH-sensitive fluorescent reporter sybII-pHluorin from the plasma membrane during endocytosis. The retrieval of other SV protein cargo reporters still occurred, however their recapture proceeded with slower kinetics. This slowing of SV retrieval kinetics in the absence of synaptophysin did not impact on global SV turnover. These results identify a specific and selective requirement for synaptophysin in the retrieval of sybII during SV endocytosis and suggest that their interaction may act as an adjustable regulator of SV retrieval efficiency

    Roughness Analysis In Strained Silicon-on-insulator Wires And Films

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    Strained silicon is used to enhance performance in state-of-the-art CMOS. Under device operating conditions, the effect of strain is to reduce the carrier scattering at the channel by a smoother semiconductor surface. This has never been completely understood. This paper gives first evidence of the variation in surface roughness under realistic strained conditions. At the nanoscale, the SiO2/Si interface roughness is dependent on the scale of observation (self-affinity). To date, there is no experimental study of the SiO2/Si interface roughness scaling with strain. This work presents the effect of uniaxial and biaxial strains on the surface roughness of strained silicon-on-insulator films and wires using atomic force microscopy. Levels of strain ranging from 0% to 2.3%, encompassing those used in present CMOS devices have been investigated. It is shown that the silicon surface is affected by uniaxial and biaxial strains differently. Three surface roughness parameters have been analyzed: root mean square roughness, correlation length, and the Hurst exponent, which is used to describe the scaling behavior of a self-affine surface. The results show that the root mean square roughness decreases (up to āˆ¼ 40%) with increasing tensile strain, whereas the correlation length increases (up to āˆ¼ 63nm/%) with increasing tensile strain. The Hurst exponent also varies with strain and with the undulation wavelength regime (between āˆ¼ 0.8 and 0.2). This dependency explains why some models used to determine the carrier mobility from experiments fit the data better with a Gaussian form, whereas other models fit the data better with an exponential form.11612EPSRC; Engineering and Physical Sciences Research CouncilSong, Y., Zhou, H., Xu, Q., Luo, J., Yin, H., Yan, J., Zhong, H., (2011) J. Electron. Mater., 40, p. 1584Lee, M.L., Fitzgerald, E.A., Bulsara, M.T., Currie, M.T., Lochtefeld, A., (2005) J. Appl. 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    The interplay between screening properties and colloid anisotropy: towards a reliable pair potential for disc-like charged particles

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    The electrostatic potential of a highly charged disc (clay platelet) in an electrolyte is investigated in detail. The corresponding non-linear Poisson-Boltzmann (PB) equation is solved numerically, and we show that the far-field behaviour (relevant for colloidal interactions in dilute suspensions) is exactly that obtained within linearized PB theory, with the surface boundary condition of a uniform potential. The latter linear problem is solved by a new semi-analytical procedure and both the potential amplitude (quantified by an effective charge) and potential anisotropy coincide closely within PB and linearized PB, provided the disc bare charge is high enough. This anisotropy remains at all scales; it is encoded in a function that may vary over several orders of magnitude depending on the azimuthal angle under which the disc is seen. The results allow to construct a pair potential for discs interaction, that is strongly orientation dependent.Comment: 13 pages, 19 figure

    Regional and Hemispheric Determinants of Language Laterality: Implications for Preoperative fMRI

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    Language is typically a function of the left hemisphere but the right hemisphere is also essential in some healthy individuals and patients. This inter-subject variability necessitates the localization of language function, at the individual level, prior to neurosurgical intervention. Such assessments are typically made by comparing left and right hemisphere language function to determine ā€œlanguage lateralizationā€ using clinical tests or fMRI. Here, we show that language function needs to be assessed at the region and hemisphere specific level, because laterality measures can be misleading. Using fMRI data from 82 healthy participants, we investigated the degree to which activation for a semantic word matching task was lateralized in 50 different brain regions and across the entire cortex. This revealed two novel findings. First, the degree to which language is lateralized across brain regions and between subjects was primarily driven by differences in right hemisphere activation rather than differences in left hemisphere activation. Second, we found that healthy subjects who have relatively high left lateralization in the angular gyrus also have relatively low left lateralization in the ventral precentral gyrus. These findings illustrate spatial heterogeneity in language lateralization that is lost when global laterality measures are considered. It is likely that the complex spatial variability we observed in healthy controls is more exaggerated in patients with brain damage. We therefore highlight the importance of investigating within hemisphere regional variations in fMRI activation, prior to neuro-surgical intervention, to determine how each hemisphere and each region contributes to language processing. Hum Brain Mapp, 2010. Ā© 2010 Wiley-Liss, Inc
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