256 research outputs found

    The effect of delayed knowledge of results on the performance of a dart throwing skill

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    The purpose of this study was to investigate the effect of delayed knowledge of results on the performance of a dart throwing skill. The subjects were forty-five women students who were randomly selected from the freshman class at The University of North Carolina at Greensboro. The subjects who agreed to participate in the study were randomly assigned to one of three different groups. Each group contained fifteen subjects. Subjects threw darts over a screen at an unseen target. All three groups had an intertrial interval of 20 seconds. Group I received knowledge of results immediately after a response, then waited approximately 18 seconds before initiating the next response; Group II received knowledge of results 10 seconds after a response, then waited approximately 10 seconds before initiating the next response; Group III received knowledge of results 15 seconds after a response, then waited approximately 5 seconds before initiating the next response. All subjects practiced for four consecutive days. Each subject threw 50 darts per day for a total of 200 trials

    Mesangial IgA1 in IgA nephropathy exhibits aberrant O-glycosylation: Observations in three patients

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    Mesangial IgA1 in IgA nephropathy exhibits aberrant O-glycosylation: Observations in three patients.BackgroundIn IgA nephropathy (IgAN), circulating IgA1 molecules display an abnormal pattern of O-glycosylation. This abnormality may potentially contribute to mesangial IgA1 deposition, but this is unproven because the O-glycosylation of mesangial IgA1 has not been analyzed.MethodsIgA1 was eluted from glomeruli isolated from the kidneys of three IgAN patients obtained after nephrectomy or at postmortem. Serum from these patients, other patients with IgAN, and controls was subjected to the same treatment as the glomerular eluates. The O-glycosylation of eluted and serum IgA1 was measured by lectin binding using an enzyme-linked immunosorbent assay-based system.ResultsIn all three cases, the lectin binding of IgA1 eluted from the glomeruli of IgAN patients was markedly higher than that of the serum IgA1 of the same individual, and also all but one of a series of serum IgA1 samples from other patients and controls.ConclusionsThe higher lectin binding of glomerular compared with serum IgA1 suggests that O-glycosylated IgA1 molecules abnormally and selectively deposit in the kidney. These results provide the first evidence that mesangial IgA1 is abnormally O-glycosylated, and support a direct role for abnormal IgA1 O-glycosylation in the mechanism of mesangial IgA deposition in IgAN

    Ergogenic effects of betaine supplementation on strength and power performance

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    <p>Abstract</p> <p>Background</p> <p>We investigated the ergogenic effects of betaine (B) supplementation on strength and power performance.</p> <p>Methods</p> <p>Twelve men (mean ± SD age, 21 ± 3 yr; mass, 79.1 ± 10.7 kg) with a minimum of 3 months resistance training completed two 14-day experimental trials separated by a 14-day washout period, in a balanced, randomized, double-blind, repeated measures, crossover design. Prior to and following 14 days of twice daily B or placebo (P) supplementation, subjects completed two consecutive days (D1 and D2) of a standardized high intensity strength/power resistance exercise challenge (REC). Performance included bench, squat, and jump tests.</p> <p>Results</p> <p>Following 14-days of B supplementation, D1 and D2 bench throw power (1779 ± 90 and 1788 ± 34 W, respectively) and isometric bench press force (2922 ± 297 and 2503 ± 28 N, respectively) were increased (p < 0.05) during REC compared to pre-supplementation values (1534 ± 30 and 1498 ± 29 W, respectively; 2345 ± 64 and 2423 ± 84 N, respectively) and corresponding P values (1374 ± 128 and 1523 ± 39 W; 2175 ± 92 and 2128 ± 56 N, respectively). Compared to pre-supplementation, vertical jump power and isometric squat force increased (p < 0.05) on D1 and D2 following B supplementation. However, there were no differences in jump squat power or the number of bench press or squat repetitions.</p> <p>Conclusion</p> <p>B supplementation increased power, force and maintenance of these measures in selected performance measures, and these were more apparent in the smaller upper-body muscle groups.</p

    Assembly of α-Glucan by GlgE and GlgB in Mycobacteria and Streptomycetes

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    Actinomycetes, such as mycobacteria and streptomycetes, synthesize α-glucan with α-1,4 linkages and α-1,6 branching to help evade immune responses and to store carbon. α-Glucan is thought to resemble glycogen except for having shorter constituent linear chains. However, the fine structure of α-glucan and how it can be defined by the maltosyl transferase GlgE and branching enzyme GlgB were not known. Using a combination of enzymolysis and mass spectrometry, we compared the properties of α-glucan isolated from actinomycetes with polymer synthesized in vitro by GlgE and GlgB. We now propose the following assembly mechanism. Polymer synthesis starts with GlgE and its donor substrate, α-maltose 1-phosphate, yielding a linear oligomer with a degree of polymerization (∼16) sufficient for GlgB to introduce a branch. Branching involves strictly intrachain transfer to generate a C chain (the only constituent chain to retain its reducing end), which now bears an A chain (a nonreducing end terminal branch that does not itself bear a branch). GlgE preferentially extends A chains allowing GlgB to act iteratively to generate new A chains emanating from B chains (nonterminal branches that themselves bear a branch). Although extension and branching occur primarily with A chains, the other chain types are sometimes extended and branched such that some B chains (and possibly C chains) bear more than one branch. This occurs less frequently in α-glucans than in classical glycogens. The very similar properties of cytosolic and capsular α-glucans from Mycobacterium tuberculosis imply GlgE and GlgB are sufficient to synthesize them both

    CTCF genetic alterations in endometrial carcinoma are pro-tumorigenic

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    CTCF is a haploinsufficient tumour suppressor gene with diverse normal functions in genome structure and gene regulation. However the mechanism by which CTCF haploinsufficiency contributes to cancer development is not well understood. CTCF is frequently mutated in endometrial cancer. Here we show that most CTCF mutations effectively result in CTCF haploinsufficiency through nonsense-mediated decay of mutant transcripts, or loss-of-function missense mutation. Conversely, we identified a recurrent CTCF mutation K365T, which alters a DNA binding residue, and acts as a gain-of-function mutation enhancing cell survival. CTCF genetic deletion occurs predominantly in poor prognosis serous subtype tumours, and this genetic deletion is associated with poor overall survival. In addition, we have shown that CTCF haploinsufficiency also occurs in poor prognosis endometrial clear cell carcinomas and has some association with endometrial cancer relapse and metastasis. Using shRNA targeting CTCF to recapitulate CTCF haploinsufficiency, we have identified a novel role for CTCF in the regulation of cellular polarity of endometrial glandular epithelium. Overall, we have identified two novel pro-tumorigenic roles (promoting cell survival and altering cell polarity) for genetic alterations of CTCF in endometrial cancer

    Phylogenomics and the rise of the angiosperms

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    Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods1, 2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome3, 4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins5–7. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes8. This 15-fold increase in genus-level sampling relative to comparable nuclear studies9 provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade

    Can selenium deficiency in Malawi be alleviated through consumption of agro-biofortified maize flour? Study protocol for a randomised, double-blind, controlled trial

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    Micronutrient deficiencies including selenium (Se) are widespread in Malawi and potentially underlie a substantial disease burden, particularly among poorer and marginalised populations. Concentrations of Se in staple cereal crops can be increased through application of Se fertilisers – a process known as agronomic biofortification (agro-biofortification) – and this may contribute to alleviating deficiencies. The Addressing Hidden Hunger with Agronomy (AHHA) trial aims to establish the efficacy of this approach for improving Se status in rural Malawi

    The assessment of the prognosis of musculoskeletal conditions in older adults presenting to general practice: a research protocol

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    BACKGROUND: Musculoskeletal conditions represent a common reason for consulting general practice yet with the exception of low back pain, relatively little is known about the prognosis of these disorders. Recent evidence suggests that common 'generic' factors may be of value when assessing prognosis, irrespective of the location of the pain. This study will test a generic assessment tool used as part of the general practice consultation to determine prognosis of musculoskeletal complaints. METHODS/DESIGN: Older adults (aged 50 years and over) presenting to six general practices with musculoskeletal complaints will be assessed as part of the routine consultation using a generic assessment of prognosis. Participants will receive a self-completion questionnaire at baseline, three, six and 12 months post consultation to gather further data on pain, disability and psychological status. The primary outcome measure is participant's global rating of change. DISCUSSION: Prognosis is considered to be a fundamental component of scientific medicine yet prognostic research in primary care settings is currently neglected and prognostic enquiry is disappearing from general medical textbooks. This study aims to address this issue by examining the use of generic prognostic factors in a general practice setting

    The Knee Clinical Assessment Study – CAS(K). A prospective study of knee pain and knee osteoarthritis in the general population

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    BACKGROUND: Knee pain affects an estimated 25% of the adult population aged 50 years and over. Osteoarthritis is the most common diagnosis made in older adults consulting with knee pain in primary care. However, the relationship between this diagnosis and both the current disease-based definition of osteoarthritis and the regional pain syndrome of knee pain and disability is unclear. Expert consensus, based on current evidence, views the disease and the syndrome as distinct entities but the clinical usefulness of these two approaches to classifying knee pain in older adults has not been established. We plan to conduct a prospective, population-based, observational cohort study to investigate the relative merits of disease-based and regional pain syndrome-based approaches to classification and prognosis of knee pain in older adults. METHODS: All patients aged 50 years and over registered with three general practices in North Staffordshire will be invited to take part in a two-stage postal survey. Respondents to this survey phase who indicate that they have experienced knee pain within the previous 12 months will be invited to attend a research clinic for a detailed assessment. This will consist of clinical interview, physical examination, digital photography, plain x-rays, anthropometric measurement and a brief self-complete questionnaire. All consenting clinic attenders will be followed up by (i) general practice medical record review, (ii) repeat postal questionnaire at 18-months

    Phylogenomics and the rise of the angiosperms

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    Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods1,2^{1,2}. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome3,4^{3,4}. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins57^{5–7}. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes8^{8}. This 15-fold increase in genus-level sampling relative to comparable nuclear studies9^{9} provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade
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