1,490 research outputs found

    Spatial variation of the physical and biomechanical properties within an equestrian arena surface

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    There is limited information about spatial variation of equestrian arena surfaces despite unequivocal evidence to suggest that lack of uniformity increases risk of injury. Spatial differences in the functional properties of an arena are likely to be due to a number of intrinsic and extrinsic characteristics including variation in the physical properties of the surface. The aim of this work was to examine spatial variation of peak load (cushioning) across an arena surface and investigate the influence that physical properties had on these variations using Principal Component Analysis. Sampling (n=61) of a 20 m by 65 m indoor synthetic equestrian arena surface occurred in one day using an Orono biomechanical surface tester (OBST). The OBST was used at every location to measure peak load (dropped twice on the same point). A 200 g sample of the surface was taken from the point of impact (at every location) and the physical properties were assessed in the laboratory. Samples were oven dried at 45⁰C for 24 hours in order to measure moisture content and percentage binder was quantified using Soxhlet extraction. Sand particle size distribution were determined using sieving and sedimentation methods and percentage organic matter was achieved by burning off organic material using a muffle furnace at 440⁰C. The surface was characterized by three principal components (PC1, PC2 and PC3). Peak load and moisture were the first principal components that accounted for 41% of surface variation. Percentage organic matter and percentage binder were identified as PC2 (20%) and PC3 (18%) respectively. This highlights their respective importance in surface variation. There was a moderate negative correlation between moisture and peak load (rs = 54%; P<0.0001) however cluster analysis revealed that peak load and moisture were grouped into five areas of similarity that corresponded to sample location, reinforced using an ANOVA (P<0.0001). The findings demonstrate an effective method of assessing uniformity and additionally, identify physical factors relevant to the load carrying capacity of this specific surface. Uneven surfaces can influence horse and rider safety therefore recognizing appropriate techniques to monitor spatial variation and implement relevant maintenance, is of key importance to equestrian athletes

    Impact of musculoskeletal symptoms on physical functioning and quality of life among treated people with HIV in high and low resource settings: a case study of the UK and Zambia

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    Background Musculoskeletal symptoms in people living with HIV (PLWH) such as pain, joint stiffness, and fatigue are commonly reported. Prevalence rates of up to 45%, 79% and 88% respectively have been reported. However, very little is known about differences in prevalence and impact of musculoskeletal symptoms on physical functioning and quality of life of PLWH on effective combined antiretroviral treatment (cART) in high and low-resource settings. Methods A cross-sectional study of PLWH on effective cART enrolled from two large urban clinics in the UK and Zambia was conducted in 2016. Eligible participants had no history of trauma to the joints within 4 weeks of recruitment, or documented evidence of previous rheumatic disease. Current musculoskeletal symptoms, functional ability, and health-related quality of life were evaluated using the health assessment (HAQ) and quality-of-life short form (SF-36) self-reported questionnaires. Results 214 patients were enrolled (108:UK and 106:Zambia). Participants from Zambia were younger (47 vs 44 years) and had significantly lower CD4 counts (640 vs 439 cells/mL p = 0.018) compared to those from the UK, while the UK group had lived with HIV longer (11 vs 6 years; p<0.001) and reported more comorbidities than the Zambian group (66% vs 26%; p<0.001). Musculoskeletal pain was common in both groups (UK:69% vs Zambia:61% p = 0.263) but no significant differences in physical functional capacity between the groups were observed. However, the UK group had significantly worse quality of life measurements (general health, vitality, mental health, emotional, and social functioning) associated with musculoskeletal symptoms compared to the Zambian group (p<0.001). Conclusions Musculoskeletal symptoms in PLWH from both the UK and Zambia were common. PLWH in the UK reported worse quality of life measures associated with musculoskeletal symptoms compared to those in Zambia, suggesting that factors such as mental health, patient expectations and multimorbidity might play a role in determining well-being and quality of life of PLWH with musculoskeletal symptoms

    Comparison of equipment used to measure shear properties in equine arena surfaces

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    The design of a novel apparatus, the Glen Withy torque tester (GWTT), for measuring horizontal shear properties in equine sport surfaces is described. Previous research has considered the effect of vertical loading on equine performance and injury but only limited discussion has concerned the grip or horizontal motion of the hoof. The horizontal support of the hoof by the surface must be sufficient to avoid excess slip without overloading the limb. The GWTT measures the torque necessary to twist an artificial hoof that is being pushed into the surface under a consistently applied vertical load. Its output was validated using a steel surface, then was used to test two sand and fibre surfaces (waxed and non-waxed) through rotations of 40–140°, and vertical loads of 157–1138 N. An Orono biomechanical surface tester (OBST) measured longitudinal shear and vertical force, whilst a traction tester measured rotational shear after being dropped onto the surfaces. A weak, but significant, linear relationship was found between rotational shear measured using the GWTT and longitudinal shear quantified using the OBST. However, only the GWTT was able to detect significant differences in shear resistance between the surfaces. Future work should continue to investigate the strain rate and non-linear load response of surfaces used in equestrian sports. Measurements should be closely tied to horse biomechanics and should include information on the maintenance condition and surface composition. Both the GWTT and the OBST are necessary to adequately characterise all the important functional properties of equine sport surfaces

    Anomalous ferromagnetic spin fluctuations in an antiferromagnetic insulator Pr_{1-x}Ca_{x}MnO_{3}

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    The high temperature paramagnetic state in an antiferromagnetic (AFM) insulator Pr_{1-x}Ca_{x}MnO_{3} is characterized by the ferromagnetic (FM) spin fluctuations with an anomalously small energy scale. The FM fluctuations show a precipitous decrease of the intensity at the charge ordering temperature T_{CO}, but persist below T_{CO}, and vanish at the AFM transition temperature T_{N}. These results demonstrate the importance of the spin ordering for the complete switching of the FM fluctuation in doped manganites.Comment: REVTeX, 5 pages, 4 figures, submitted to Phys. Rev.

    Randomized, double-blind, placebo-controled clinical trial of sublingual immunotherapy in natural rubber latex allergic patients

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    <p>Abstract</p> <p>Background</p> <p>Natural rubber latex allergy is a common and unsolved health problem. Since the avoidance of exposure is very difficult, immunotherapy is strongly recommended, but before its use in patients, it is essential to prove the efficacy and safety of extracts.</p> <p>The aim of the present randomised, double-blind, placebo-controlled clinical trial was to assess the efficacy and tolerability of latex sublingual immunotherapy in adult patients undergoing permanent latex avoidance.</p> <p>Methods</p> <p>Twenty-eight adult latex-allergic patients (5 males and 23 females), with mean age of 39 years (range 24-57) were randomized to receive a commercial latex-sublingual immunotherapy or placebo during one year, followed by another year of open, active therapy. The following outcomes were measured at baseline and at the end of first and second year of follow-up: skin prick test, gloves-use score, conjunctival challenge test, total and specific IgE, basophil activation test, and adverse reactions monitoring.</p> <p>Results</p> <p>No significant difference in any of the efficacy <it>in vivo </it>variables was observed between active and placebo groups at the end of the placebo-controlled phase, nor when each group was compared with their baseline values at the end of the two year-study. An improvement in the average percentage of basophils activated was observed. During the induction phase, 4 reactions in the active group and 5 in the placebo group were recorded. During the maintenance phase, two patients dropped out due to pruritus and to acute dermatitis respectively.</p> <p>Conclusion</p> <p>Further studies are needed to evaluate latex-sublingual immunotherapy, since efficacy could not be demonstrated in adult patients with avoidance of the allergen.</p> <p>Trial registration number</p> <p><a href="http://www.anzctr.org.au/ACTRN12611000543987.aspx">ACTRN12611000543987</a></p

    Imaging NeuroVascular, Endothelial and STructural Integrity in prepAration to TrEat Small Vessel Diseases. The INVESTIGATE-SVDs study Protocol

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    Background: Sporadic cerebral small vessel disease (SVD) and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) share clinical and neuroimaging features and possibly vascular dysfunction(s). However few studies have included both conditions, assessed more than one vascular dysfunction simultaneously, or included more than one centre. The INVESTIGATE-SVDs study will assess several cerebrovascular dysfunctions with MRI in participants with sporadic SVD or CADASIL at three European centres. Methods: We will recruit participants with sporadic SVDs (ischaemic stroke or vascular cognitive impairment) and CADASIL in Edinburgh, Maastricht and Munich. We will perform detailed clinical and neuropsychological phenotyping of the participants, and neuroimaging including structural MRI, cerebrovascular reactivity MRI (CVR: using carbon dioxide challenge), phase contrast MRI (arterial, venous and CSF flow and pulsatility), dynamic contrast-enhanced MRI (blood brain barrier (BBB) leakage) and multishell diffusion imaging. Participants will measure their blood pressure (BP) and its variability over seven days using a telemetric device. Discussion: INVESTIGATE-SVDs will assess the relationships of BBB integrity, CVR, pulsatility and CSF flow in sporadic SVD and CADASIL using a multisite, multimodal MRI protocol. We aim to establish associations between these measures of vascular function, risk factors particularly BP and its variability, and brain parenchymal lesions in these two SVD phenotypes. Additionally we will test feasibility of complex multisite MRI, provide reliable intermediary outcome measures and sample size estimates for future trials