720 research outputs found

    Does dynamic stability govern propulsive force generation in human walking?

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    Before succumbing to slower speeds, older adults may walk with a diminished push-off to prioritize stability over mobility. However, direct evidence for trade-offs between push-off intensity and balance control in human walking, independent of changes in speed, has remained elusive. As a critical first step, we conducted two experiments to investigate: (i) the independent effects of walking speed and propulsive force (FP) generation on dynamic stability in young adults, and (ii) the extent to which young adults prioritize dynamic stability in selecting their preferred combination of walking speed and FP generation. Subjects walked on a force-measuring treadmill across a range of speeds as well as at constant speeds while modulating their FP according to a visual biofeedback paradigm based on real-time force measurements. In contrast to improvements when walking slower, walking with a diminished push-off worsened dynamic stability by up to 32%. Rather, we find that young adults adopt an FP at their preferred walking speed that maximizes dynamic stability. One implication of these findings is that the onset of a diminished push-off in old age may independently contribute to poorer balance control and precipitate slower walking speeds

    Improving Bioscience Research Reporting:The ARRIVE Guidelines for Reporting Animal Research

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    In the last decade the number of bioscience journals has increased enormously, with many filling specialised niches reflecting new disciplines and technologies. The emergence of open-access journals has revolutionised the publication process, maximising the availability of research data. Nevertheless, a wealth of evidence shows that across many areas, the reporting of biomedical research is often inadequate, leading to the view that even if the science is sound, in many cases the publications themselves are not “fit for purpose”, meaning that incomplete reporting of relevant information effectively renders many publications of limited value as instruments to inform policy or clinical and scientific practice [1–21]. A recent review of clinical research showed that there is considerable cumulative waste of financial resources at all stages of the research process, including as a result of publications that are unusable due to poor reporting [22]. It is unlikely that this issue is confined to clinical research [2–14,16–20]

    Follicular fluid high density lipoprotein-associated micronutrient levels are associated with embryo fragmentation during IVF

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    To investigate whether follicular fluid lipid-soluble micronutrients are associated with embryo morphology parameters during IVF. Follicle fluid and oocytes were obtained prospectively from 81 women. Embryo morphology parameters were used as surrogate markers of oocyte health. HDL lipids and lipid-soluble micronutrients were analyzed by high-pressure liquid chromatography. Non-parametric bi-variate analysis and multivariable ordinal logistic regression models were employed to examine associations between biochemical and embryo morphology parameters. Follicular fluid HDL cholesterol (r = −0.47, p < 0.01), α-tocopherol (r = −0.41, p < 0.01), δ-tocopherol (r = −0.38, p < 0.05) and β-cryptoxanthine (r = −0.42, p < 0.01) are negatively correlated with embryo fragmentation. Ordinal logistic regression models indicate that a 0.1 μmol/L increase in β-cryptoxanthine, adjusted for γ-tocopherol, is associated with a 75% decrease in the cumulative odds of higher embryo fragmentation (p = 0.010). Follicular fluid HDL micronutrients may play an important role in the development of the human oocyte as evident by embryo fragmentation during IVF

    The orbits of the quadruple star system 88 Tau A from PHASES differential astrometry and radial velocity

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    We have used high precision differential astrometry from the Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES) project and radial velocity measurements covering a time-span of 20 years to determine the orbital parameters of the 88 Tau A system. 88 Tau is a complex hierarchical multiple system comprising a total of six stars; we have studied the brightest 4, consisting of two short-period pairs orbiting each other with an 18-year period. We present the first orbital solution for one of the short-period pairs, and determine the masses of the components and distance to the system to the level of a few percent. In addition, our astrometric measurements allow us to make the first determination of the mutual inclinations of the orbits. We find that the sub-systems are not coplanar.Comment: Corrected Author Ordering; 12 Pages, Accepted for publication in Ap

    Single-Nucleotide Polymorphisms and Markers of Oxidative Stress in Healthy Women

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    Purpose There is accumulating evidence that oxidative stress is an important contributor to carcinogenesis. We hypothesized that genetic variation in genes involved in maintaining antioxidant/ oxidant balance would be associated with overall oxidative stress. Methods We examined associations between single nucleotide polymorphisms (SNPs) in MnSOD, GSTP1, GSTM1, GPX1, GPX3, and CAT genes and thiobarbituric acid-reactive substances (TBARS), a blood biomarker of oxidative damage, in healthy white women randomly selected from Western New York (n = 1402). We used general linear models to calculate age-adjusted geometric means of TBARS across the variants. We also examined the associations within strata of menopausal status. Results For MnSOD, being heterozygous was associated with lower geometric means of TBARS (less oxidative stress), 1.28 mg/dL, compared to homozygous T-allele or homozygous Callele, 1.35 mg/dL, and 1.31 mg/dL correspondingly (p for trend = 0.01). This difference remained among postmenopausal women, 1.40 mg/dL for TT, 1.32 mg/dL for TC, and 1.34mg/dL for CC (p for trend 0.015); it was attenuated among premenopausal women. SNPs in the other genes examined (GSTP1, GSTM1, GPX1, GPX3, and CAT) were not associated with TBARS. Conclusions Our findings suggest that genetic variation in MnSOD gene may be associated with oxidative status, particularly among postmenopausal women

    A Study of 3CR Radio Galaxies from z = 0.15 to 0.65. II. Evidence for an Evolving Radio Structure

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    Radio structure parameters were measured from the highest quality radio maps available for a sample of 3CR radio galaxies in the redshift range 0.15 < z < 0.65. Combined with similar data for quasars in the same redshift range, these morphology data are used in conjunction with a quantification of the richness of the cluster environment around these objects (the amplitude of the galaxy-galaxy spatial covariance function, Bgg) to search for indirect evidence of a dense intracluster medium (ICM). This is done by searching for confinement and distortions of the radio structure that are correlated with Bgg. Correlations between physical size and hot spot placement with Bgg show evidence for an ICM only at z 0.4, suggesting an epoch of z ~ 0.4 for the formation of an ICM in these Abell richness class 0-1, FR2-selected clusters. X-ray selected clusters at comparable redshifts, which contain FR1 type sources exclusively, are demonstrably richer than the FR2-selected clusters found in this study. The majority of the radio sources with high Bgg values at z < 0.4 can be described as ``fat doubles'' or intermediate FR2/FR1s. The lack of correlation between Bgg and bending angle or Bgg and lobe length asymmetry suggests that these types of radio source distortion are caused by something other than interaction with a dense ICM. Thus, a large bending angle cannot be used as an unambiguous indicator of a rich cluster around powerful radio sources. These results support the hypothesis made in Paper 1 that cluster quasars fade to become FR2s, then FR1s, on a timescale of 0.9 Gyrs (for H0 = 50 km s^-1 Mpc^-1).Comment: 44 pages, 8 figures, 2 tables; to be published in the September 2002 issue of The Astronomical Journa

    Protocol for the Foot in Juvenile Idiopathic Arthritis trial (FiJIA): a randomised controlled trial of an integrated foot care programme for foot problems in JIA

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    &lt;b&gt;Background&lt;/b&gt;: Foot and ankle problems are a common but relatively neglected manifestation of juvenile idiopathic arthritis. Studies of medical and non-medical interventions have shown that clinical outcome measures can be improved. However existing data has been drawn from small non-randomised clinical studies of single interventions that appear to under-represent the adult population suffering from juvenile idiopathic arthritis. To date, no evidence of combined therapies or integrated care for juvenile idiopathic arthritis patients with foot and ankle problems exists. &lt;b&gt;Methods/design&lt;/b&gt;: An exploratory phase II non-pharmacological randomised controlled trial where patients including young children, adolescents and adults with juvenile idiopathic arthritis and associated foot/ankle problems will be randomised to receive integrated podiatric care via a new foot care programme, or to receive standard podiatry care. Sixty patients (30 in each arm) including children, adolescents and adults diagnosed with juvenile idiopathic arthritis who satisfy the inclusion and exclusion criteria will be recruited from 2 outpatient centres of paediatric and adult rheumatology respectively. Participants will be randomised by process of minimisation using the Minim software package. The primary outcome measure is the foot related impairment measured by the Juvenile Arthritis Disability Index questionnaire's impairment domain at 6 and 12 months, with secondary outcomes including disease activity score, foot deformity score, active/limited foot joint counts, spatio-temporal and plantar-pressure gait parameters, health related quality of life and semi-quantitative ultrasonography score for inflammatory foot lesions. The new foot care programme will comprise rapid assessment and investigation, targeted treatment, with detailed outcome assessment and follow-up at minimum intervals of 3 months. Data will be collected at baseline, 6 months and 12 months from baseline. Intention to treat data analysis will be conducted. A full health economic evaluation will be conducted alongside the trial and will evaluate the cost effectiveness of the intervention. This will consider the cost per improvement in Juvenile Arthritis Disability Index, and cost per quality adjusted life year gained. In addition, a discrete choice experiment will elicit willingness to pay values and a cost benefit analysis will also be undertaken
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