658 research outputs found
Elastic behaviour of the carotid artery in intact spontaneously hypertensive rats
Intact spontaneously hypertensive rats (SHR) were studied to assess the effect of prolonged antihypertensive treatment on the elastic behaviour of the external carotid artery. Thirty-week-old SHR received the ACE inhibitor captopril, the ateriolar dilator hydralazine or their vehicle for 6 weeks. These rats were compared to normotensive, vehicle treated WKY rats. The internal diameter of the carotid artery was measured continuously in halothane-anaesthetized rats using an echo-tracking device, and intra-arterial pressure was also monitored continuously, on the controlateral side. Captopril- and hydralazinetreated SHR as well as normotensive controls had similar blood pressure values. No significant shift in the distensibility-pressure curves was observed among vehicle-treated SHR and WKY rats or the SHR which had received captopril or hydralazine. Histological examination of the carotid artery fixed ex vivo with paraformaldehyde showed a significant increase in cross-sectional area in vehicle-treated SHR as compared to their normotensive counterparts. These results therefore suggest that the elastic behaviour of elastic arteries is not necessarily altered by the structural changes developing in response to hypertensio
Injuries Following Implementation of a Progressive Load Carriage Program in United States Marine Corps Training
PURPOSE: The overall physical demands placed on recruits completing United States Marine Corps (USMC) training is high and comes concomitantly with high rates of injuries. Load carriage with heavy loads is of particular concern. However, load carriage conditioning, if optimised, can reduce injury risk. METHODS: Retrospective injury data of recruits completing training informed this study. Data were drawn from recruits completing an original load carriage (OLC) program (n=2,363) and those completing a modified load carriage (LCMOD) program (n=681). Musculoskeletal injury data were drawn from the USMC San Diego sports medicine injury database. A population estimate of the OLC:LCMOD relative risk ratio (RR) was calculated. RESULTS: The proportion of injuries sustained by the LCMOD cohort (n=268; 39%) was notably lower than that sustained by the OLC cohort (n=1,372; 58%). The reoccurrence rate *f injury for LCMOD soldiers compared to the OLC was 0.68 (95% CI 0.61 to 0.75). The leading nature of injury (i.e., sprains and strains) was consistent between both cohorts (OLC: n=396; 29% vs. LCMOD: n=66; 25%). Inflammation (n=172; 13%) and fractures (n=144; 11%) were next most common for OLC recruits; while pain (n=58; 22%) and medial tibial stress syndrome (n=18; 8%) were next most common for LCMOD recruits. While stress reactions were proportionally higher in LCMOD (n=17; 6%) when compared to OLC (n=4; 0.3%), stress fractures were proportionality lower (LCMOD: n=9; 3% vs. OLC: n=114; 8%). Pre-existing / chronic injuries were higher in LCMOD (+5%) while new overuse injuries were lower (-7%). Totalling 65% (OLC) and 70% (LCMOD) of reported injuries the knee, lower leg, ankle, and foot were the top 4 bodily sites of injuries, although there were variations in the orders of presentations (See Table 1 for top 10 bodily sites). RELEVANCE: Careful periodisation and planning of a load carriage program can reduce injuries without reducing training outcomes
In-depth mesocrystal formation analysis of microwave-assisted synthesis of LiMnPO4nanostructures in organic solution
In the present work, we report on the preparation of LiMnPO4 (lithiophilite) nanorods and mesocrystals composed of self-assembled rod subunits employing microwave-assisted precipitation with processing times on the time scale of minutes. Starting from metal salt precursors and H3PO4 as phosphate source, single-phase LiMnPO4 powders with grain sizes of approx. 35 and 65 nm with varying morphologies were obtained by tailoring the synthesis conditions using rac-1-phenylethanol as solvent. The mesocrystal formation, microstructure and phase composition were determined by electron microscopy, nitrogen physisorption, X-ray diffraction (including Rietveld refinement), dynamic light scattering, X-ray absorption and X-ray photoelectron spectroscopy, and other techniques. In addition, we investigated the formed organic matter by gas chromatography coupled with mass spectrometry in order to gain a deeper understanding of the dissolution\u2013precipitation process. Also, we demonstrate that the obtained LiMnPO4 nanocrystals can be redispersed in polar solvents such as ethanol and dimethylformamide and are suitable as building blocks for the fabrication of nanofibers via electrospinning
Gender differences in injuries sustained during United States Marine Corps training
Aim: To investigate gender-specific differences in injuries in United States Marine Corps (USMC) trainees.Design: Retrospective cohort study.Method: Point-of-care injury data for USMC recruits (females=94; males=681) completing training were drawn from the Marine Corps Recruit Depot San Diego sports medicine injury database and analysed descriptively. The male: female incidence rate ratio (IRR) was calculated.Results: Male trainees suffered more injuries (male=268; 39%; female n=22; 23%; IRR=1.68 (95% CI 1.33 to 2.1)). Sprains and strains were the leading nature of injury (female=41%; male=25%) followed by pain(female=23%; male=22%). The leading type of injury was ânew overuse injuriesâ for both genders (54% each). Female trainees experienced more acute injuries (36% versus 26%). While female (55%) and male (58%)rates of âmoderateâ injuries were similar, female trainees experienced more âmildâ injuries (36% versus 25%). The knee (female=27%: male=23%) and lower leg (female=23%: male=21%) were the leading injury sites. All injuries were to the lower limbs in female trainees; male trainees also reported injuries to the upper limb (12%) and trunk (8%).Conclusion: Female trainees experienced fewer injuries than male trainees, with more being mild. Both genders had similar natures of injuries in similar body sites except that male trainees reported some upper body and trunk injuries.</div
Steam reforming of methanol over Cu/ZrO<sub>2</sub>/CeO<sub>2</sub> catalysts: a kinetic study
Structureâactivity relationships of ternary Cu/ZrO<sub>2</sub>/CeO<sub>2</sub> catalysts for methanol steam reforming
Elastic behaviour of the carotid artery in intact spontaneously hypertensive rats
Intact spontaneously hypertensive rats (SHR) were studied to assess the effect of prolonged antihypertensive treatment on the elastic behaviour of the external carotid artery. Thirty-week-old SHR received the ACE inhibitor captopril, the arteriolar dilator hydralazine or their vehicle for 6 weeks. These rats were compared to normotensive, vehicle treated WKY rats. The internal diameter of the carotid artery was measured continuously in halothane-anaesthetized rats using an echo-tracking device, and intra-arterial pressure was also monitored continuously, on the contralateral side. Captopril- and hydralazine-treated SHR as well as normotensive controls had similar blood pressure values. No significant shift in the distensibility-pressure curves was observed among vehicle-treated SHR and WKY rats or the SHR which had received captopril or hydralazine. Histological examination of the carotid artery fixed ex vivo with paraformaldehyde showed a significant increase in cross-sectional area in vehicle-treated SHR as compared to their normotensive counterparts. These results therefore suggest that the elastic behaviour of elastic arteries is not necessarily altered by the structural changes developing in response to hypertension
Transport regimes of cold gases in a two-dimensional anisotropic disorder
We numerically study the dynamics of cold atoms in a two-dimensional
disordered potential. We consider an anisotropic speckle potential and focus on
the classical regime, which is relevant to some recent experiments. First, we
study the behavior of particles with a fixed energy and identify different
transport regimes. For low energy, the particles are classically localized due
to the absence of a percolating cluster. For high energy, the particles undergo
normal diffusion and we show that the diffusion constants scale algebraically
with the particle energy, with an anisotropy factor which significantly differs
from that of the disordered potential. For intermediate energy, we find a
transient sub-diffusive regime, which is relevant to the time scale of typical
experiments. Second, we study the behavior of a cold-atomic gas with an
arbitrary energy distribution, using the above results as a groundwork. We show
that the density profile of the atomic cloud in the diffusion regime is
strongly peaked and, in particular, that it is not Gaussian. Its behavior at
large distances allows us to extract the energy-dependent diffusion constants
from experimental density distributions. For a thermal cloud released into the
disordered potential, we show that our numerical predictions are in agreement
with experimental findings. Not only does this work give insights to recent
experimental results, but it may also serve interpretation of future
experiments searching for deviation from classical diffusion and traces of
Anderson localization.Comment: 19 pages, 16 figure
Disorder-Induced Phase Control in Superfluid Fermi-Bose Mixtures
We consider a mixture of a superfluid Fermi gas of ultracold atoms and a
Bose-Einstein condensate of molecules possessing a continuous U(1) (relative
phase) symmetry. We study the effects that a spatially random
photo-associative-dissociative symmetry breaking coupling of the systems. Such
coupling allows to control the relative phase between a superfluid order
parameter of the Fermi system and the condensate wavefunction of molecules for
temperatures below the BCS critical temperature. The presented mechanism of
phase control belongs to the general class of disorder-induced order phenomena
that rely on breaking of continuous symmetry.Comment: 4 pages, 2 figure
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