958 research outputs found

    A study of the relationship between the general physical fitness of adolescents aged 15 ā€“ 19 years and their parents

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    The purpose of this study was to determine the degree of familial resemblance in general physical fitness between adolescents and their parents. Data was gathered from a sample of adolescent-parent pairs. Parents with children between the ages of 15-19 years of age were recruited by means of a poster campaign in the Abergele, Colwyn Bay and Llandudno postal areas of Conwy, North Wales. A sample of 32 adolescent-parent pairs was employed in this research. Participants completed the International Physical Activity Questionnaire, and had anthropometric measures taken. The performance of adolescent-parent pairs was then measured for aerobic capacity, static strength, muscular endurance and flexibility. A correlational research design was employed for the project. The level of significance was set at p<0.01. All statistical calculations were performed using SPSS (Version 14.0 for Windows). Familial correlation models were fitted directly to the data under the assumption that the family data follow a multivariate normal distribution. The results indicated significant parent - offspring resemblance for weight (0.50), aerobic capacity (0.52), muscular endurance (0.48) and flexibility (0.60) and significant father/son resemblance for weight (0.29), height (0.46) and grip strength (0.39), together with mother/daughter resemblance for weight (0.33) and height (0.48). The results suggest that familial and perhaps genetic, factors are important in explaining the variance in general physical fitness

    Structure and function studies on the LH1-RC core complex from a range of photosynthetic purple bacteria

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    The LH1-RC core complexes from a range of purple bacterial species were investigated. The complexes were isolated by solubilisation with the detergent LDAO, then purified using a combination of techniques such as sucrose gradient centrifugation, anion exchange and gel filtration chromatography. The integrity of the complexes during purification was monitored by means of absorption spectroscopy. This showed that the stability of the detergent solubilised cores was species dependent. The most stable cores were obtained from Rps. acidophila, Rps. cryptolactis, Rps. palustris and Chr. vinosum. The least stable core complexes were from Rv. gelatinosus and Rs. rubrum. The intactness and stability of the purified cores was further investigated by circular dichroism (CD) spectroscopy. This technique provided a much more sensitive spectral test for intactness than that offered by absorption spectroscopy. CD spectra in the NIR region confirmed that the cores from Rv. gelatinosus and Rs. rubrum denatured during purification. The purified core complexes were screened for their suitability for forming 3-D crystals using vapour diffusion methods. Core complex crystals did not form when LDAO was used as detergent or when ammonium sulphate and potassium phosphate were used as precipitants. However, when LDAO was exchanged for other detergents, such as cholate and heptyl thioglucoside, and PEG was used as a precipitant core complex crystals did form. The presence of MgCl2 and other small additives seemed an absolute requirement for crystal formation. The best crystals were obtained using core complex from Rps. acidophila strain 10050. Preliminary characterisation of one of these crystals showed it diffracted X-rays to a resolution of 7.6A. Data analysis suggested a space group with putative tetragonal P4 symmetry and unit cell dimensions of a=b=156.56A and c=181.11A, and alpha=beta=gamma=90.0Ā°. Due to a problem of irreproducibility the crystallisation experiments failed to yield crystals of a sufficient quality to allow a structural determination of the LH1-RC core. The LH1 (B880) complex from Rh. marinum was also isolated and purified, and the effects of chemical oxidation on its absorption and fluorescence emission spectra was investigated. Mild chemical oxidation of the LH1 complex, by addition of 10mM potassium ferricyanide, caused a 2-3% bleaching of the 880nm Qy absorption band. In contrast, at the same ferricyanide concentration, fluorescence emission intensity of the complex was quenched by about 50%. This result demonstrated that oxidation of a very few bacteriochlorophyll molecules in the LH1 ring is enough to completely quench its fluorescence. This suggests the possibility of redox control of energy transfer. The antenna arrangement in the photosynthetic membrane of the 7750 strain of the purple bacterium Rps. acidophila was investigated by means of fluorescence induction spectroscopy. The membrane of this species is thought to be composed of LH1-RC core complexes which are surrounded by peripheral LH2 complexes. The sigmoidicity of fluorescence induction curves was used to probe the excitonic connectivity of RC's, and this information were used to gain information on the structural arrangement of the antennae. The data obtained excluded models of the Rps. acidophila photosynthetic unit (PSU) that assume aggregates of LH1-RC complexes or linear chains of LH1-RC complexes to which LH2 complexes are attached on the periphery. Rather, they support the model suggested by Papiz et al. (1996) in which peripheral LH2 rings tightly surround each core complex circumferentially

    Corticosteroid implants for chronic non-infectious uveitis.

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    BACKGROUND: Uveitis is a term used to describe a heterogeneous group of intraocular inflammatory diseases of the anterior, intermediate, and posterior uveal tract (iris, ciliary body, choroid). Uveitis is the fifth most common cause of vision loss in high-income countries, accounting for 5% to 20% of legal blindness, with the highest incidence of disease in the working-age population.Corticosteroids are the mainstay of acute treatment for all anatomical subtypes of non-infectious uveitis and can be administered orally, topically with drops or ointments, by periocular (around the eye) or intravitreal (inside the eye) injection, or by surgical implantation. OBJECTIVES: To determine the efficacy and safety of steroid implants in people with chronic non-infectious posterior uveitis, intermediate uveitis, and panuveitis. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (Issue 10, 2015), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to November 2015), EMBASE (January 1980 to November 2015), PubMed (1948 to November 2015), Latin American and Caribbean Health Sciences Literature Database (LILACS) (1982 to November 2015), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (last searched 15 April 2013), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic search for studies. We last searched the electronic databases on 6 November 2015.We also searched reference lists of included study reports, citation databases, and abstracts and clinical study presentations from professional meetings. SELECTION CRITERIA: We included randomized controlled trials comparing either fluocinolone acetonide (FA) or dexamethasone intravitreal implants with standard-of-care therapy with at least six months of follow-up after treatment. We included studies that enrolled participants of all ages who had chronic non-infectious posterior uveitis, intermediate uveitis, or panuveitis with vision that was better than hand-motion. DATA COLLECTION AND ANALYSIS: Two review authors independently reviewed studies for inclusion. Two review authors independently extracted data and assessed the risk of bias for each study. MAIN RESULTS: We included data from two studies (619 eyes of 401 participants) that compared FA implants with standard-of-care therapy. Both studies used similar standard-of-care therapy that included administration of prednisolone and, if needed, immunosuppressive agents. The studies included participants from Australia, France, Germany, Israel, Italy, Portugal, Saudi Arabia, Spain, Switzerland, Turkey, the United Kingdom, and the United States. We assessed both studies at high risk of performance and detection bias.Only one study reported our primary outcome, recurrence of uveitis at any point during the study through 24 months. The evidence, judged as moderate-quality, showed that a FA implant probably prevents recurrence of uveitis compared with standard-of-care therapy (risk ratio (RR) 0.29, 95% confidence interval (CI) 0.14 to 0.59; 132 eyes). Both studies reported safety outcomes, and moderate-quality evidence showed increased risks of needing cataract surgery (RR 2.98, 95% CI 2.33 to 3.79; 371 eyes) and surgery to lower intraocular pressure (RR 7.48, 95% CI 3.94 to 14.19; 599 eyes) in the implant group compared with standard-of-care therapy through two years of follow-up. No studies compared dexamethasone implants with standard-of-care therapy. AUTHORS\u27 CONCLUSIONS: After considering both benefits and harms reported from two studies in which corticosteroids implants were compared with standard-of-care therapy, we are unable to conclude that the implants are superior to traditional systemic therapy for the treatment of non-infectious uveitis. These studies exhibited heterogeneity in design and outcomes that measured efficacy. Pooled findings regarding safety outcomes suggest increased risks of post-implant surgery for cataract and high intraocular pressure compared with standard-of-care therapy

    Insight into determinants of substrate binding and transport in a multidrug efflux protein

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    Multidrug resistance arising from the activity of integral membrane transporter proteins presents a global public health threat. In bacteria such as Escherichia coli, transporter proteins belonging to the major facilitator superfamily make a considerable contribution to multidrug resistance by catalysing efflux of myriad structurally and chemically different antimicrobial compounds. Despite their clinical relevance, questions pertaining to mechanistic details of how these promiscuous proteins function remain outstanding, and the role(s) played by individual amino acid residues in recognition, binding and subsequent transport of different antimicrobial substrates by multidrug efflux members of the major facilitator superfamily requires illumination. Using in silico homology modelling, molecular docking and mutagenesis studies in combination with substrate binding and transport assays, we identified several amino acid residues that play important roles in antimicrobial substrate recognition, binding and transport by Escherichia coli MdtM, a representative multidrug efflux protein of the major facilitator superfamily. Furthermore, our studies suggested that ā€˜aromatic clampsā€™ formed by tyrosine and phenylalanine residues located within the substrate binding pocket of MdtM may be important for antimicrobial substrate recognition and transport by the protein. Such ā€˜clampsā€™ may be a structurally and functionally important feature of all major facilitator multidrug efflux proteins

    A Dominant-Negative PPARĪ³ Mutant Promotes Cell Cycle Progression and Cell Growth in Vascular Smooth Muscle Cells

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    PPARĪ³ ligands have been shown to have antiproliferative effects on many cell types. We herein report that a synthetic dominant-negative (DN) PPARĪ³ mutant functions like a growth factor to promote cell cycle progression and cell proliferation in human coronary artery smooth muscle cells (CASMCs). In quiescent CASMCs, adenovirus-expressed DN-PPARĪ³ promoted G1ā†’S cell cycle progression, enhanced BrdU incorporation, and increased cell proliferation. DN-PPARĪ³ expression also markedly enhanced positive regulators of the cell cycle, increasing Rb and CDC2 phosphorylation and the expression of cyclin A, B1, D1, and MCM7. Conversely, overexpression of wild-type (WT) or constitutively-active (CA) PPARĪ³ inhibited cell cycle progression and the activity and expression of positive regulators of the cell cycle. DN-PPARĪ³ expression, however, did not up-regulate positive cell cycle regulators in PPARĪ³-deficient cells, strongly suggesting that DN-PPARĪ³ effects on cell cycle result from blocking the function of endogenous wild-type PPARĪ³. DN-PPARĪ³ expression enhanced phosphorylation of ERK MAPKs. Furthermore, the ERK specific-inhibitor PD98059 blocked DN-PPARĪ³-induced phosphorylation of Rb and expression of cyclin A and MCM7. Our data thus suggest that DN-PPARĪ³ promotes cell cycle progression and cell growth in CASMCs by modulating fundamental cell cycle regulatory proteins and MAPK mitogenic signaling pathways in vascular smooth muscle cells (VSMCs)

    Digital Fingerprinting of Microstructures

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    Finding efficient means of fingerprinting microstructural information is a critical step towards harnessing data-centric machine learning approaches. A statistical framework is systematically developed for compressed characterisation of a population of images, which includes some classical computer vision methods as special cases. The focus is on materials microstructure. The ultimate purpose is to rapidly fingerprint sample images in the context of various high-throughput design/make/test scenarios. This includes, but is not limited to, quantification of the disparity between microstructures for quality control, classifying microstructures, predicting materials properties from image data and identifying potential processing routes to engineer new materials with specific properties. Here, we consider microstructure classification and utilise the resulting features over a range of related machine learning tasks, namely supervised, semi-supervised, and unsupervised learning. The approach is applied to two distinct datasets to illustrate various aspects and some recommendations are made based on the findings. In particular, methods that leverage transfer learning with convolutional neural networks (CNNs), pretrained on the ImageNet dataset, are generally shown to outperform other methods. Additionally, dimensionality reduction of these CNN-based fingerprints is shown to have negligible impact on classification accuracy for the supervised learning approaches considered. In situations where there is a large dataset with only a handful of images labelled, graph-based label propagation to unlabelled data is shown to be favourable over discarding unlabelled data and performing supervised learning. In particular, label propagation by Poisson learning is shown to be highly effective at low label rates

    N6-methyladenosine is required for the hypoxic stabilization of specific mRNAs

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    Post-transcriptional regulation of mRNA during oxygen deprivation, or hypoxia, can affect the survivability of cells. Hypoxia has been shown to increase stability of a subset of ischemia-related mRNAs, including VEGF. RNA binding proteins and miRNAs have been identified as important for post-transcriptional regulation of individual mRNAs, but corresponding mechanisms that regulate global stability are not well understood. Recently, mRNA modification by N6-methyladenosine (m6A) has been shown to be involved in post-transcriptional regulation processes including mRNA stability and promotion of translation, but the role of m6A in the hypoxia response is unknown. In this study, we investigate the effect of hypoxia on RNA modifications including m6A. Our results show hypoxia increases m6A content of poly(A)+ messenger RNA (mRNA), but not in total or ribosomal RNA in HEK293T cells. Using m6A mRNA immunoprecipitation, we identify specific hypoxia-modified mRNAs, including glucose transporter 1 (Glut1) and c-Myc, which show increased m6A levels under hypoxic conditions. Many of these mRNAs also exhibit increased stability, which was blocked by knockdown of m6A-specific methyltransferases METTL3/14. However, the increase in mRNA stability did not correlate with a change in translational efficiency or the steady-state amount of their proteins. Knockdown of METTL3/14 did reveal that m6A is involved in recovery of translational efficiency after hypoxic stress. Therefore, our results suggest that an increase in m6A mRNA during hypoxic exposure leads to post-transcriptional stabilization of specific mRNAs and contributes to the recovery of translational efficiency after hypoxic stress

    Equity trade-offs in conservation decision making

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    Conservation decisions increasingly involve multiple environmental and social objectives, which result in complex decision contexts with high potential for trade-offs. Improving social equity is one such objective that is often considered an enabler of successful outcomes and a virtuous ideal in itself. Despite its idealized importance in conservation policy, social equity is often highly simplified or ill-defined and is applied uncritically. What constitutes equitable outcomes and processes is highly normative and subject to ethical deliberation. Different ethical frameworks may lead to different conceptions of equity through alternative perspectives of what is good or right. This can lead to different and potentially conflicting equity objectives in practice. We promote a more transparent, nuanced, and pluralistic conceptualization of equity in conservation decision making that particularly recognizes where multidimensional equity objectives may conflict. To help identify and mitigate ethical conflicts and avoid cases of good intentions producing bad outcomes, we encourage a more analytical incorporation of equity into conservation decision making particularly during mechanistic integration of equity objectives. We recommend that in conservation planning motivations and objectives for equity be made explicit within the problem context, methods used to incorporate equity objectives be applied with respect to stated objectives, and, should objectives dictate, evaluation of equity outcomes and adaptation of strategies be employed during policy implementation

    The FIRST-Optical-VLA Survey for Lensed Radio Lobes

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    We present results from a survey for gravitationally lensed radio lobes. Lensed lobes are a potentially richer source of information about galaxy mass distributions than lensed point sources, which have been the exclusive focus of other recent surveys. Our approach is to identify radio lobes in the FIRST catalog and then search optical catalogs for coincident foreground galaxies, which are candidate lensing galaxies. We then obtain higher-resolution images of these targets at both optical and radio wavelengths, and obtain optical spectra for the most promising candidates. We present maps of several radio lobes that are nearly coincident with galaxies. We have not found any new and unambiguous cases of gravitational lensing. One radio lobe in particular, FOV J0743+1553, has two hot spots that could be multiple images produced by a z=0.19 spiral galaxy, but the lensing interpretation is problematic.Comment: 38 pages, 18 figures, aastex, accepted to A
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