314 research outputs found

    LONGITUDINAL ADAPTATIONS IN MUSCLE STRENGTH, FUNCTIONAL PERFORMANCE, GAIT BIOMECHANICS, AND PATIENT-REPORTED FUNCTION AFTER UNILATERAL TOTAL KNEE ARTHROPLASTY

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    Objective: The aims of this research were to identify gaps in the literature related to impairments after total knee arthroplasty (TKA) (Aim 1) and define recovery between 3 and 6 months after TKA across four domains: 1) hip and knee muscle performance, 2) functional performance, 3) patient-reported function, and 4) biomechanics of walking and stair descent (Aim 2). Additionally, this project sought to explore the relationships between each domain (Aim 3) and establish predictive models to allow clinicians to use clinical measures to predict future gait biomechanics in patients after TKA (Aim 4). Ultimately, the results of this research would quantify post-rehabilitative recovery after TKA and identify potential targets for objective criteria needed for discharge from outpatient rehabilitation. Participants: Thirty-nine individuals completed the study protocol, 21 in the TKA group (7 male, 14 female, height: 1.68 ± 0.08 m, mass: 90.95 ± 21.04 kg, BMI: 32.27 ± 7.4 kg/m2, Age: 60.6 ± 8.1 years) and 18 matched control subjects (7 male, 11 female, height: 1.69 ± 0.10 m, mass: 83.69 ± 20.2 kg, BMI: 29.2 ± 5.5 kg/m2, Age: 61.2 ± 8.8 years). Methods: For Aim 1, a systematic review of the literature related to the four previously stated domains was conducted. In Aims 2-4, a longitudinal design with 3 and 6 months post-surgery assessment time points was used for the TKA group. At both assessment time points, participants underwent maximal voluntary isometric strength testing of bilateral hip abduction, hip external rotation, and knee extension to determine peak strength and rate of torque development (RTD). Participants also performed the five-time sit-to-stand test (FTSTS) and underwent three-dimensional motion analysis while walking at a self-selected speed and during a stair descent task. Patient-reported function was measured using the Knee Injury & Osteoarthritis Outcome Score (KOOS). The control subjects completed the same testing procedures at a single time point. Main Outcome Measures: Outcomes were assessed across four domains. The first domain included peak isometric muscle strength and RTD of hip abduction, hip external rotation, and knee extension. The second and third domains represented functional performance as assessed by the FTSTS and patient-reported function as measured by the KOOS, respectively. The final domain included hip and knee joint kinematics and kinetics during walking and stair descent as measured using three-dimensional motion analysis and inverse dynamics. Statistical Analysis: Aim 1: no formal statistics were utilized in the systematic review. Aim 2 utilized paired sample t-tests for between-limb (operative vs non-operative) and within-limb (3 months vs 6 months post-surgery) comparisons across all four domains. Additionally, independent two-sample t-tests were used to compare the operative and non-operative limbs of the TKA group to the matched control group. In Aim 3, Pearson product-moment correlations were performed to assess the relationships between muscle performance, FTSTS performance, and KOOS scores in the TKA group at 1) 3 months post-surgery, 2) 6 months post-surgery, and 3) between the improvements in these outcomes from 3 to 6 months post-surgery. Lastly, Aim 4 utilized Pearson product-moment correlations and stepwise multiple linear regressions to develop a predictive model using clinical measures assessed at 3 months post-operatively to predict knee flexion excursion during walking at 6 months post-surgery. Results: Aim 1: Improvements in KOOS scores, deficits in peak quadriceps strength, and altered knee joint biomechanics during walking are present during the first 6 months following TKA. Limited evidence exists regarding hip muscle strength deficits, FTSTS performance, and stair descent biomechanics after TKA. Aim 2: Quadriceps and hip external rotation peak strength and RTD, FTSTS performance, gait and stair descent biomechanics, and KOOS scores all demonstrated significant, but modest, improvement between 3 and 6 months post-surgery. However, persistent deficits in quadriceps and hip external rotation peak strength and RTD, FTSTS, movement biomechanics, and KOOS scores compared to control subjects indicate incomplete recovery after TKA both immediately after rehabilitation and following the early post-rehabilitative period. Aim 3: Peak hip muscle strength and FTSTS performance are significantly correlated with KOOS Pain, activities of daily living, and Sport subscales at 3 months post-surgery. Fewer relationships were observed at 6 months post-surgery and between improvements from 3 to 6 months. Aim 4: Quadriceps RTD, hip external rotation RTD, and FTSTS performance were predictive of knee flexion excursion during walking, with quadriceps RTD the strongest of the three predictors. Faster quadriceps RTD, slower hip external rotation RTD, and faster FTSTS performance are predicted to lead to greater knee flexion excursion. Conclusions: Modest improvement in muscle strength and RTD, FTSTS performance, patient-reported function, and biomechanics occur during the post-rehabilitative period after TKA, but all domains remain impaired compared to matched control subjects. Furthermore, muscle strength and RTD and FTSTS performance contribute to greater patient-perceived function and future knee flexion excursion during walking. In order to improve outcomes across domains after TKA, emphasizing improvement in muscle strength, RTD, and FTSTS ability during the first 3 months after surgery is critical as persistent deficits do not resolve by 6 months post-surgery. Lastly, maximizing quadriceps RTD by 3 months post-surgery is likely to lead to improved walking biomechanics at 6 months post-surgery

    Gender-dependent differences in plasma matrix metalloproteinase-8 elevated in pulmonary tuberculosis.

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    Tuberculosis (TB) remains a global health pandemic and greater understanding of underlying pathogenesis is required to develop novel therapeutic and diagnostic approaches. Matrix metalloproteinases (MMPs) are emerging as key effectors of tissue destruction in TB but have not been comprehensively studied in plasma, nor have gender differences been investigated. We measured the plasma concentrations of MMPs in a carefully characterised, prospectively recruited clinical cohort of 380 individuals. The collagenases, MMP-1 and MMP-8, were elevated in plasma of patients with pulmonary TB relative to healthy controls, and MMP-7 (matrilysin) and MMP-9 (gelatinase B) were also increased. MMP-8 was TB-specific (p<0.001), not being elevated in symptomatic controls (symptoms suspicious of TB but active disease excluded). Plasma MMP-8 concentrations inversely correlated with body mass index. Plasma MMP-8 concentration was 1.51-fold higher in males than females with TB (p<0.05) and this difference was not due to greater disease severity in men. Gender-specific analysis of MMPs demonstrated consistent increase in MMP-1 and -8 in TB, but MMP-8 was a better discriminator for TB in men. Plasma collagenases are elevated in pulmonary TB and differ between men and women. Gender must be considered in investigation of TB immunopathology and development of novel diagnostic markers

    Evaluating the Dimensionality of First-Grade Written Composition

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    Purpose—We examined dimensions of written composition using multiple evaluative approaches such as an adapted 6+1 trait scoring, syntactic complexity measures, and productivity measures. We further examined unique relations of oral language and literacy skills to the identified dimensions of written composition. Method—A large sample of first grade students (N = 527) was assessed on their language, reading, spelling, letter writing automaticity, and writing in the spring. Data were analyzed using a latent variable approach including confirmatory factor analysis and structural equation modeling. Results—The seven traits in the 6+1 trait system were best described as two constructs: substantive quality, and spelling and writing conventions. When the other evaluation procedures such as productivity and syntactic complexity indicators were included, four dimensions emerged: substantive quality, productivity, syntactic complexity, and spelling and writing conventions. Language and literacy predictors were differentially related to each dimension in written composition. Conclusions—These four dimensions may be a useful guideline for evaluating developing beginning writer’s compositions

    Why alternative teenagers self-harm: exploring the link between non-suicidal self-injury, attempted suicide and adolescent identity

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    Background: The term ‘self-harm’ encompasses both attempted suicide and non-suicidal self-injury (NSSI). Specific adolescent subpopulations such as ethnic or sexual minorities, and more controversially, those who identify as ‘Alternative’ (Goth, Emo) have been proposed as being more likely to self-harm, while other groups such as ‘Jocks’ are linked with protective coping behaviours (for example exercise). NSSI has autonomic (it reduces negative emotions) and social (it communicates distress or facilitates group ‘bonding’) functions. This study explores the links between such aspects of self-harm, primarily NSSI, and youth subculture.&lt;p&gt;&lt;/p&gt; Methods: An anonymous survey was carried out of 452 15 year old German school students. Measures included: identification with different youth cultures, i.e. Alternative (Goth, Emo, Punk), Nerd (academic) or Jock (athletic); social background, e.g. socioeconomic status; and experience of victimisation. Self-harm (suicide and NSSI) was assessed using Self-harm Behavior Questionnaire and the Functional Assessment of Self-Mutilation (FASM).&lt;p&gt;&lt;/p&gt; Results: An “Alternative” identity was directly (r ≈ 0.3) and a “Jock” identity inversely (r ≈ -0.1) correlated with self-harm. “Alternative” teenagers self-injured more frequently (NSSI 45.5% vs. 18.8%), repeatedly self-injured, and were 4–8 times more likely to attempt suicide (even after adjusting for social background) than their non-Alternative peers. They were also more likely to self-injure for autonomic, communicative and social reasons than other adolescents.&lt;p&gt;&lt;/p&gt; Conclusions: About half of ‘Alternative’ adolescents’ self-injure, primarily to regulate emotions and communicate distress. However, a minority self-injure to reinforce their group identity, i.e. ‘To feel more a part of a group’

    A Secure Semi-Field System for the Study of Aedes aegypti

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    Novel vector control strategies require validation in the field before they can be widely accepted. Semi-field system (SFS) containment facilities are an intermediate step between laboratory and field trials that offer a safe, controlled environment that replicates field conditions. We developed a SFS laboratory and cage complex that simulates an urban house and yard, which is the primary habitat for Aedes aegypti, the mosquito vector of dengue in Cairns Australia. The SFS consists of a Quarantine Insectary Level-2 (QIC-2) laboratory, containing 3 constant temperature rooms, that is connected to two QIS-2 cages for housing released mosquitoes. Each cage contains the understory of a “Queenslander” timber house and associated yard. An automated air conditioning system keeps temperature and humidity to within 1°C and 5% RH of ambient conditions, respectively. Survival of released A. aegypti was high, especially for females. We are currently using the SFS to investigate the invasion of strains of Wolbachia within populations of A. aegypti

    Recommendation of short tandem repeat profiling for authenticating human cell lines, stem cells, and tissues

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    Cell misidentification and cross-contamination have plagued biomedical research for as long as cells have been employed as research tools. Examples of misidentified cell lines continue to surface to this day. Efforts to eradicate the problem by raising awareness of the issue and by asking scientists voluntarily to take appropriate actions have not been successful. Unambiguous cell authentication is an essential step in the scientific process and should be an inherent consideration during peer review of papers submitted for publication or during review of grants submitted for funding. In order to facilitate proper identity testing, accurate, reliable, inexpensive, and standardized methods for authentication of cells and cell lines must be made available. To this end, an international team of scientists is, at this time, preparing a consensus standard on the authentication of human cells using short tandem repeat (STR) profiling. This standard, which will be submitted for review and approval as an American National Standard by the American National Standards Institute, will provide investigators guidance on the use of STR profiling for authenticating human cell lines. Such guidance will include methodological detail on the preparation of the DNA sample, the appropriate numbers and types of loci to be evaluated, and the interpretation and quality control of the results. Associated with the standard itself will be the establishment and maintenance of a public STR profile database under the auspices of the National Center for Biotechnology Information. The consensus standard is anticipated to be adopted by granting agencies and scientific journals as appropriate methodology for authenticating human cell lines, stem cells, and tissues

    Mutation of von Hippel–Lindau Tumour Suppressor and Human Cardiopulmonary Physiology

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    BACKGROUND: The von Hippel–Lindau tumour suppressor protein–hypoxia-inducible factor (VHL–HIF) pathway has attracted widespread medical interest as a transcriptional system controlling cellular responses to hypoxia, yet insights into its role in systemic human physiology remain limited. Chuvash polycythaemia has recently been defined as a new form of VHL-associated disease, distinct from the classical VHL-associated inherited cancer syndrome, in which germline homozygosity for a hypomorphic VHL allele causes a generalised abnormality in VHL–HIF signalling. Affected individuals thus provide a unique opportunity to explore the integrative physiology of this signalling pathway. This study investigated patients with Chuvash polycythaemia in order to analyse the role of the VHL–HIF pathway in systemic human cardiopulmonary physiology. METHODS AND FINDINGS: Twelve participants, three with Chuvash polycythaemia and nine controls, were studied at baseline and during hypoxia. Participants breathed through a mouthpiece, and pulmonary ventilation was measured while pulmonary vascular tone was assessed echocardiographically. Individuals with Chuvash polycythaemia were found to have striking abnormalities in respiratory and pulmonary vascular regulation. Basal ventilation and pulmonary vascular tone were elevated, and ventilatory, pulmonary vasoconstrictive, and heart rate responses to acute hypoxia were greatly increased. CONCLUSIONS: The features observed in this small group of patients with Chuvash polycythaemia are highly characteristic of those associated with acclimatisation to the hypoxia of high altitude. More generally, the phenotype associated with Chuvash polycythaemia demonstrates that VHL plays a major role in the underlying calibration and homeostasis of the respiratory and cardiovascular systems, most likely through its central role in the regulation of HIF

    Are sciences essential and humanities elective? Disentangling competing claims for humanities research public value

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    [EN] Recent policy discourse suggests that arts and humanities research is seen as being less useful to society than other disciplines, notably in science, technology, engineering and mathematics. The paper explores how this assumption s construction has been built and whether it is based upon an unfair prejudice: we argue for a prima facie case to answer in assuming that arts and humanities research s lower societal value. We identify a set of claims circulating in policy circles regarding science, technology, engineering and math- ematics research and arts and humanities research s differences. We find two groups: arts and humanities research is less useful than science, technology, engineering and mathematics, and arts and humanities research is merely differently useful. We argue that empirical analysis is necessary to disentangle which ones are true to assess whether policy-making is being based on rational and evidence-based claims. We argue that debates about public research value should recognise that humanities have different (but equally valid) kinds of societal value.This work was supported by the Spanish Ministry of Education, which funded the PhD research fellowship of Julia Olmos Peñuela through the F.P.U program [AP2007- 01850]. The research fellowship took place in the framework of the HERAVALUE project, Measuring the public value of arts and humanities research, financially supported by the HERA Joint Research Programme, cofunded by AHRC, AKA, DASTI, ETF, FNR, FWF, HAZU, IRCHSS, MHEST, NWO, RANNIS, RCN, VR and The European Community FP7 2007-2013, under the Socio-economic Sciences and Humanities programme. The authors would like to thank the editors and two anonymous referees for their invaluable comments. Any errors or omissions remain the authors’ responsibilitieOlmos-Peñuela, J.; Benneworth, P.; Castro-Martínez, E. (2015). Are sciences essential and humanities elective? Disentangling competing claims for humanities research public value. Arts and Humanities in Higher Education. 14(1):61-78. https://doi.org/10.1177/1474022214534081S617814

    Status and prospects for renewable energy using wood pellets from the southeastern United States

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    The ongoing debate about costs and benefits of wood-pellet based bioenergy production in the southeastern United States (SE USA) requires an understanding of the science and context influencing market decisions associated with its sustainability. Production of pellets has garnered much attention as US exports have grown from negligible amounts in the early 2000s to 4.6 million metric tonnes in 2015. Currently, 98% of these pellet exports are shipped to Europe to displace coal in power plants. We ask, ‘How is the production of wood pellets in the SE USA affecting forest systems and the ecosystem services they provide?’ To address this question, we review current forest conditions and the status of the wood products industry, how pellet production affects ecosystem services and biodiversity, and what methods are in place to monitor changes and protect vulnerable systems. Scientific studies provide evidence that wood pellets in the SE USA are a fraction of total forestry operations and can be produced while maintaining or improving forest ecosystem services. Ecosystem services are protected by the requirement to utilize loggers trained to apply scientifically based best management practices in planning and implementing harvest for the export market. Bioenergy markets supplement incomes to private rural landholders and provide an incentive for forest management practices that simultaneously benefit water quality and wildlife and reduce risk of fire and insect outbreaks. Bioenergy also increases the value of forest land to landowners, thereby decreasing likelihood of conversion to nonforest uses. Monitoring and evaluation are essential to verify that regulations and good practices are achieving goals and to enable timely responses if problems arise. Conducting rigorous research to understand how conditions change in response to management choices requires baseline data, monitoring, and appropriate reference scenarios. Long-term monitoring data on forest conditions should be publicly accessible and utilized to inform adaptive management

    The Psychological Science Accelerator: Advancing Psychology Through a Distributed Collaborative Network

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    Source at https://doi.org/10.1177/2515245918797607.Concerns about the veracity of psychological research have been growing. Many findings in psychological science are based on studies with insufficient statistical power and nonrepresentative samples, or may otherwise be limited to specific, ungeneralizable settings or populations. Crowdsourced research, a type of large-scale collaboration in which one or more research projects are conducted across multiple lab sites, offers a pragmatic solution to these and other current methodological challenges. The Psychological Science Accelerator (PSA) is a distributed network of laboratories designed to enable and support crowdsourced research projects. These projects can focus on novel research questions or replicate prior research in large, diverse samples. The PSA’s mission is to accelerate the accumulation of reliable and generalizable evidence in psychological science. Here, we describe the background, structure, principles, procedures, benefits, and challenges of the PSA. In contrast to other crowdsourced research networks, the PSA is ongoing (as opposed to time limited), efficient (in that structures and principles are reused for different projects), decentralized, diverse (in both subjects and researchers), and inclusive (of proposals, contributions, and other relevant input from anyone inside or outside the network). The PSA and other approaches to crowdsourced psychological science will advance understanding of mental processes and behaviors by enabling rigorous research and systematic examination of its generalizability
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