6,431 research outputs found
SEX-SPECIFIC MUSCULOSKELETAL ASYMMETRIES FOLLOWING ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION
Olivia A. Anderson 1, Allen L. Redinger1, Emery L. Mintz 2,3, Caleb C. Voskuil 2, Jason A. Mogonye 3,4, Joshua C. Carr 2,3 & Breanne S. Baker 1
1 Oklahoma State University, Stillwater, Oklahoma; 2 Texas Christian University, Fort Worth, Texas; 3 Texas Christian University School of Medicine, Fort Worth, Texas; 4 JPS Health Network, Fort Worth, Texas
Females are predisposed to more risk factors for primary and secondary anterior cruciate ligament (ACL) injury. Factors such as lower-body bone, muscle, and fat tissue asymmetries post-ACL reconstruction (ACLR) influence recovery; however, if these asymmetries are sex-specific is unknown. PURPOSE: This study aimed to evaluate the influence of sex on musculoskeletal asymmetries and perception of knee function post-ACLR. METHODS: Females (n=11) and males (n=11) with a history of ACLR provided voluntary informed consent prior to completing Dual-energy X-ray Absorptiometry (DXA) scans to measure lower-body bone mineral content (BMC), Fat %, and lean mass (LM), additionally inter-limb asymmetry indices (AI%) were calculated for each tissue. Perceptions of knee function were captured via the International Knee Documentation Committee (IKDC) instrument and participants provided surgical information such as time since surgery and graft type used. Initial Independent t-tests were used to assess sex differences for all variables; however, time since surgery was included as a clinically significant covariate for subsequent analyses. Additionally, Pearson’s Correlations Coefficients evaluated the association between AI% and IKDC scores. Lastly, Cohen’s effect sizes (d) were calculated and α=0.05. RESULTS: Females had greater asymmetries for BMC and LM and lower IKDC scores compared to males post-ACLR (adjusted p≤0.027, d=0.40–0.74). Furthermore, a sex-dependent correlation was observed as tissue asymmetries were negatively correlated with IKDC scores for only females (all r≥0.755; p≤0.007). CONCLUSIONS: These data suggested females with a history of ACLR have greater musculoskeletal tissue asymmetries compared to males, which are associated with lower perceptions of knee function. As such, sex-specific ACLR rehabilitation and musculoskeletal monitoring protocols may need to be developed as we aim to reduce females’ elevated risk for ACL reinjury
Comparing seated pressures in daily wheelchair and sports equipment and investigating the skin protective effects of padded shorts.
Background:
Adaptive sports are promoted for individuals with spinal cord injury to increase overall health and prevent cardiovascular and metabolic diseases, but the potential risk of pressure ulcer development with adaptive equipment (AE) is a concern. Current research has found seated pressures in AE that exceed clinically accepted values but no studies have measured pressure with a padded short to assess for its potential pressure reducing effects.
Objective:
Our study sought to evaluate average and peak seating pressure in both static and dynamic sport-specific positions, with and without the presence of three types of over-the-counter padded bicycle shorts, in multiple types of adaptive equipment (AE): Hand cycle, quad rugby, basketball, and mountain hand cycle.
Methods:
Part One. Pre/Post test design with subjects as their own control. Eight adults with SCI (C5-T6) were pressure mapped under static and dynamic conditions in their daily use wheelchair (WC) and AE. Three conditions were mapped: Daily WC, AE without bicycle shorts, and AE with shorts. AE included: Hand-cycle, quad rugby, basketball, and mountain hand-cycle.
Part Two. Static pressure readings in a hand-cycle were taken on 16 able-bodied subjects with and without an impact short and a full-coverage padded short.
Part three. Single subject with T5 SCI was pressure mapped in static and dynamic conditions with and without the full-coverage padded short in a basketball chair and mountain hand-cycle.
Average pressure (AP) and peak pressure (PP) recordings were taken for 60 seconds (400 frames) using the TekScan Pressure Mapping System. For static recordings the participants were instructed to sit still, while for dynamic recordings participants simulated sport or activity specific movements.
Results:
Part 1. Significant differences were found between the daily chair and AE for both AP and PP in the static condition (p \u3c 0.05), as well as AP in the dynamic condition (p
Part 2. The impact short significantly increased static PP and AP (p0.05).
Part 3. The full-coverage padded short increased AP and PP in the basketball chair, decreased AP in the mountain hand cycle and increased PP in the mountain hand cycle.
Discussion:
Pressure differences between daily WC and AE in static conditions suggests that athletes who are not moving or sitting on the sidelines in their AE may be at greater risk of tissue breakdown than athletes who are playing and experiencing pressure-relieving positions during movement. Padded shorts as a method to reduce PP and AP yielded variable results which may have been influenced by type of AE and posture in the AE. Thus seated posture may influence the pressure relieving capabilities of a padded short.
Conclusion: Donning a padded short as a method of skin protection yields highly variable changes in PP and AP and pressure mapping should be performed prior to use in AE by the SCI population.
Works Cited: Berthold, J., Dicianno, B.E. & Cooper, R.A. (2013). Pressure mapping to assess seated pressure distributions and the potential risk for skin ulceration in a population of sledge hockey players and control subjects. Disability and Rehabilitation. Assistive Technology, 8(5), 387-39http://doi.org/10.3109/17483107.2013.769123 Darrah, S.D., Dcianno, B.E., Berthold, J., McCoy, A., Haas, M., & Cooper, R.A. (2016). Measuring static seated pressure distributions and risk for skin pressure ulceration in ice sledge hockey players. Disability and Rehabilitation. Assistive Technology, 11(3), 241-246. http://doi.org/10.3109/17483107.2014.92193
Spectrum and Thermodynamics of the one-dimensional supersymmetric t-J model with exchange and hopping
We derive the spectrum and the thermodynamics of the one-dimensional
supersymmetric t-J model with long range hopping and spin exchange using a set
of maximal-spin eigenstates. This spectrum confirms the recent conjecture that
the asymptotic Bethe-ansatz spectrum is exact. By empirical determining the
spinon degeneracies of each state, we are able to explicitly construct the free
energy.Comment: 13 pages, Latex, (published in PRB46, 6639 (1992)
Census politics in deeply divided societies
Population censuses in societies that are deeply divided along ethnic, religious or linguistic lines can be sensitive affairs – particularly where political settlements seek to maintain peace through the proportional sharing of power between groups. This brief sets out some key findings from a research project investigating the relationship between census politics and the design of political institutions in Bosnia and Herzegovina, Kenya, Lebanon and Northern Ireland
An open label, dose response study to determine the effect of a dietary supplement on dihydrotestosterone, testosterone and estradiol levels in healthy males
<p>Abstract</p> <p>Background</p> <p>Maintaining endogenous testosterone (T) levels as men age may slow the symptoms of sarcopenia, andropause and decline in physical performance. Drugs inhibiting the enzyme 5α-reductase (5AR) produce increased blood levels of T and decreased levels of dihydrotestosterone (DHT). However, symptoms of gynecomastia have been reported due to the aromatase (AER) enzyme converting excess T to estradiol (ES). The carotenoid astaxanthin (AX) from <it>Haematococcus pluvialis</it>, Saw Palmetto berry lipid extract (SPLE) from <it>Serenoa repens </it>and the precise combination of these dietary supplements, Alphastat<sup>® </sup>(Mytosterone(™)), have been reported to have inhibitory effects on both 5AR and AER in-vitro. Concomitant regulation of both enzymes in-vivo would cause DHT and ES blood levels to decrease and T levels to increase. The purpose of this clinical study was to determine if patented Alphastat<sup>® </sup>(Mytosterone(™)) could produce these effects in a dose dependent manner.</p> <p>Methods</p> <p>To investigate this clinically, 42 healthy males ages 37 to 70 years were divided into two groups of twenty-one and dosed with either 800 mg/day or 2000 mg/day of Alphastat<sup>® </sup>(Mytosterone(™)) for fourteen days. Blood samples were collected on days 0, 3, 7 and 14 and assayed for T, DHT and ES. Body weight and blood pressure data were collected prior to blood collection. One-way, repeated measures analysis of variance (ANOVA-RM) was performed at a significance level of alpha = 0.05 to determine differences from baseline within each group. Two-way analysis of variance (ANOVA-2) was performed after baseline subtraction, at a significance level of alpha = 0.05 to determine differences between dose groups. Results are expressed as means ± SEM.</p> <p>Results</p> <p>ANOVA-RM showed significant within group increases in serum total T and significant decreases in serum DHT from baseline in both dose groups at a significance level of alpha = 0.05. Significant decreases in serum ES are reported for the 2000 mg/day dose group and not the 800 mg/day dose group. Significant within group effects were confirmed using ANOVA-2 analyses after baseline subtraction. ANOVA-2 analyses also showed no significant difference between dose groups with regard to the increase of T or the decrease of DHT. It did show a significant dose dependant decrease in serum ES levels.</p> <p>Conclusion</p> <p>Both dose groups showed significant (p = 0.05) increases in T and decreases in DHT within three days of treatment with Alphastat<sup>® </sup>(Mytosterone(™)). Between group statistical analysis showed no significant (p = 0.05) difference, indicating the effect was not dose dependent and that 800 mg/per day is equally effective as 2000 mg/day for increasing T and lowering DHT. Blood levels of ES however, decreased significantly (p = 0.05) in the 2000 mg/day dose group but not in the 800 mg/day dose group indicating a dose dependant decrease in E levels.</p
Discovery of the Acoustic Faraday Effect in Superfluid 3He-B
We report the discovery of the acoustic Faraday effect in superfluid 3He-B.
The observation of this effect provides the first direct evidence for
propagating transverse acoustic waves in liquid 3He, a mode first predicted by
Landau in 1957. The Faraday rotation is large and observable because of
spontaneously broken spin-orbit symmetry in 3He-B. We compare the experimental
observations with a simulation of the transverse acoustic impedance that
includes the field-induced circular birefringence of transverse waves.Comment: 4 pages in RevTex plus 3 postscript figures; new version includes:
minor corrections to the text and an updated of list of reference
Validation of T2* in-line analysis for tissue iron quantification at 1.5 T.
BACKGROUND: There is a need for improved worldwide access to tissue iron quantification using T2* cardiovascular magnetic resonance (CMR). One route to facilitate this would be simple in-line T2* analysis widely available on MR scanners. We therefore compared our clinically validated and established T2* method at Royal Brompton Hospital (RBH T2*) against a novel work-in-progress (WIP) sequence with in-line T2* measurement from Siemens (WIP T2*). METHODS: Healthy volunteers (n = 22) and patients with iron overload (n = 78) were recruited (53 males, median age 34 years). A 1.5 T study (Magnetom Avanto, Siemens) was performed on all subjects. The same mid-ventricular short axis cardiac slice and transaxial slice through the liver were used to acquire both RBH T2* images and WIP T2* maps for each participant. Cardiac white blood (WB) and black blood (BB) sequences were acquired. Intraobserver, interobserver and interstudy reproducibility were measured on the same data from a subset of 20 participants. RESULTS: Liver T2* values ranged from 0.8 to 35.7 ms (median 5.1 ms) and cardiac T2* values from 6.0 to 52.3 ms (median 31 ms). The coefficient of variance (CoV) values for direct comparison of T2* values by RBH and WIP were 6.1-7.8 % across techniques. Accurate delineation of the septum was difficult on some WIP T2* maps due to artefacts. The inability to manually correct for noise by truncation of erroneous later echo times led to some overestimation of T2* using WIP T2* compared with the RBH T2*. Reproducibility CoV results for RBH T2* ranged from 1.5 to 5.7 % which were better than the reproducibility of WIP T2* values of 4.1-16.6 %. CONCLUSIONS: Iron estimation using the T2* CMR sequence in combination with Siemens' in-line data processing is generally satisfactory and may help facilitate global access to tissue iron assessment. The current automated T2* map technique is less good for tissue iron assessment with noisy data at low T2* values
Comparative population structure of <i>Plasmodium malariae</i> and <i>Plasmodium falciparum</i> under different transmission settings in Malawi
<b>Background:</b> Described here is the first population genetic study of Plasmodium malariae, the causative agent of quartan malaria. Although not as deadly as Plasmodium falciparum, P. malariae is more common than previously thought, and is frequently in sympatry and co-infection with P. falciparum, making its study increasingly important. This study compares the population parameters of the two species in two districts of Malawi with different malaria transmission patterns - one seasonal, one perennial - to explore the effects of transmission on population structures.
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<b>Methods:</b> Six species-specific microsatellite markers were used to analyse 257 P. malariae samples and 257 P. falciparum samples matched for age, gender and village of residence. Allele sizes were scored to within 2 bp for each locus and haplotypes were constructed from dominant alleles in multiple infections. Analysis of multiplicity of infection (MOI), population differentiation, clustering of haplotypes and linkage disequilibrium was performed for both species. Regression analyses were used to determine association of MOI measurements with clinical malaria parameters.
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<b>Results:</b> Multiple-genotype infections within each species were common in both districts, accounting for 86.0% of P. falciparum and 73.2% of P. malariae infections and did not differ significantly with transmission setting. Mean MOI of P. falciparum was increased under perennial transmission compared with seasonal (3.14 vs 2.59, p = 0.008) and was greater in children compared with adults. In contrast, P. malariae mean MOI was similar between transmission settings (2.12 vs 2.11) and there was no difference between children and adults. Population differentiation showed no significant differences between villages or districts for either species. There was no evidence of geographical clustering of haplotypes. Linkage disequilibrium amongst loci was found only for P. falciparum samples from the seasonal transmission setting.
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<b>Conclusions:</b> The extent of similarity between P. falciparum and P. malariae population structure described by the high level of multiple infection, the lack of significant population differentiation or haplotype clustering and lack of linkage disequilibrium is surprising given the differences in the biological features of these species that suggest a reduced potential for out-crossing and transmission in P. malariae. The absence of a rise in P. malariae MOI with increased transmission or a reduction in MOI with age could be explained by differences in the duration of infection or degree of immunity compared to P. falciparum
Critical Issues in the Development of Health Information Systems in Supporting Environmental Health: A Case Study of Ciguatera
Emerging environmental pressures resulting from climate change and globalization challenge the capacity of health information systems (HIS) in the Pacific to inform future policy and public health interventions. Ciguatera, a globally common marine food-borne illness, is used here to illustrate specific HIS challenges in the Pacific and how these might be overcome proactively to meet the changing surveillance needs resulting from environmental change.We review and highlight inefficiencies in the reactive nature of existing HIS in the Pacific to collect, collate, and communicate ciguatera fish poisoning data currently used to inform public health intervention. Further, we review the capacity of existing HIS to respond to new data needs associated with shifts in ciguatera disease burden likely to result from coral reef habitat disruption.Improved knowledge on the ecological drivers of ciguatera prevalence at local and regional levels is needed, combined with enhanced surveillance techniques and data management systems, to capture environmental drivers as well as health outcomes data.The capacity of public HIS to detect and prevent future outbreaks is largely dependent on the future development of governance strategies that promote proactive surveillance and health action. Accordingly, we present an innovative framework from which to stimulate scientific debate on how this might be achieved by using existing larger scale data sets and multidisciplinary collaborations
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