1,794 research outputs found

    EFFECTS OF STATIC STRETCHING ON MAXIMAL ISOKINETIC TORQUE

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    The effects of 20 seconds of agonist (AGO), antagonist (ANT) or no (NO) pre-exercise stretch on concentric (CON) and eccentric (ECC) maximal isokinetic torque produced at the knee were examined. Twelve male semi-pro rugby players performed dominant isokinetic knee extension following the specified stretch protocol. One-way Repeated Measures ANOVA revealed AGO to be significantly less (p < 0.05) than the other protocols for both CON (270 28 Nm) and ECC (309 42 Nm) torque. There was no difference between the ANT or NO for either CON (303 35 Nm and 304 38 Nm, respectively) or ECC (341 40 Nm and 33644 Nm). The results support the theory that pre-exercise agonist stretching may lead to performance decrements in maximal concentric torque production

    Plutonium stabilization in zircon: Effects of self-radiation

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    Zircon (ZrSiO4)(ZrSiO4) is the most thoroughly studied of all candidate ceramic phases for the stabilization of plutonium. Self-radiation damage from α-decay of the 239Pu,239Pu, which releases a 5.16 MeV α-particle and a 0.086 MeV 235U235U recoil nucleus, can significantly affect the structure and properties of zircon. Recent computer simulations using energy minimization techniques indicate that the lowest energy configuration occurs for a defect cluster composed of two near-neighbor Pu3+Pu3+ substitutions on Zr4+Zr4+ sites and a neighboring charge-compensating oxygen vacancy. © 2000 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87571/2/18_1.pd

    Human genes differ by their UV sensitivity estimated through analysis of UV-induced silent mutations in melanoma

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    We hypothesized that human genes differ by their sensitivity to ultraviolet (UV) exposure. We used somatic mutations detected by genome-wide screens in melanoma and reported in the Catalog Of Somatic Mutations In Cancer. As a measure of UV sensitivity, we used the number of silent mutations generated by C>T transitions in pyrimidine dimers of a given transcript divided by the number of potential sites for this type of mutations in the transcript. We found that human genes varied by UV sensitivity by two orders of magnitude. We noted that the melanoma-associated tumor suppressor gene CDKN2A was among the top five most UV-sensitive genes in the human genome. Melanoma driver genes have a higher UV-sensitivity compared with other genes in the human genome. The difference was more prominent for tumor suppressors compared with oncogene. The results of this study suggest that differential sensitivity of human transcripts to UV light may explain melanoma specificity of some driver genes. Practical significance of the study relates to the fact that differences in UV sensitivity among human genes need to be taken into consideration whereas predicting melanoma-associated genes by the number of somatic mutations detected in a given gene

    Evaluation of the limitations and methods to improve rapid phage-based detection of viable Mycobacterium avium subsp. paratuberculosis in the blood of experimentally infected cattle

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    Background Disseminated infection and bacteraemia is an underreported and under-researched aspect of Johne’s disease. This is mainly due to the time it takes for Mycobacterium avium subsp. paratuberculosis (MAP) to grow and lack of sensitivity of culture. Viable MAP cells can be detected in the blood of cattle suffering from Johne’s disease within 48 h using peptide-mediated magnetic separation (PMMS) followed by bacteriophage amplification. The aim of this study was to demonstrate the first detection of MAP in the blood of experimentally exposed cattle using the PMMS-bacteriophage assay and to compare these results with the immune response of the animal based on serum ELISA and shedding of MAP by faecal culture. Results Using the PMMS-phage assay, seven out of the 19 (37 %) MAP-exposed animals that were tested were positive for viable MAP cells although very low numbers of MAP were detected. Two of these animals were positive by faecal culture and one was positive by serum ELISA. There was no correlation between PMMS-phage assay results and the faecal and serum ELISA results. None of the control animals (10) were positive for MAP using any of the four detection methods. Investigations carried out into the efficiency of the assay; found that the PMMS step was the limiting factor reducing the sensitivity of the phage assay. A modified method using the phage assay directly on isolated peripheral blood mononuclear cells (without PMMS) was found to be superior to the PMMS isolation step. Conclusions This proof of concept study has shown that viable MAP cells are present in the blood of MAP-exposed cattle prior to the onset of clinical signs. Although only one time point was tested, the ability to detect viable MAP in the blood of subclinically infected animals by the rapid phage-based method has the potential to increase the understanding of the pathogenesis of Johne’s disease progression by warranting further research on the presence of MAP in blood

    Plume-subduction interaction forms large auriferous provinces

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    Gold enrichment at the crustal or mantle source has been proposed as a key ingredient in the production of giant gold deposits and districts. However, the lithospheric-scale processes controlling gold endowment in a given metallogenic province remain unclear. Here we provide the first direct evidence of native gold in the mantle beneath the Deseado Massif in Patagonia that links an enriched mantle source to the occurrence of a large auriferous province in the overlying crust. A precursor stage of mantle refertilisation by plume-derived melts generated a gold-rich mantle source during the Early Jurassic. The interplay of this enriched mantle domain and subduction-related fluids released during the Middle-Late Jurassic resulted in optimal conditions to produce the ore-forming magmas that generated the gold deposits. Our study highlights that refertilisation of the subcontinental lithospheric mantle is a key factor in forming large metallogenic provinces in the Earth’s crust, thus providing an alternative view to current crust-related enrichment models.Funding for this study has been provided by Millennium Science Initiative through Millennium Nucleus for Metal Tracing along Subduction Grant NC130065. Additional support was provided by FONDAP project 15090013 ‘Centro de Excelencia en Geotermia de Los Andes, CEGA’, FONDECYT projects #11140005 and #1140780, and DID-UACh project #S-2015-52. Additional funding for LA-ICP-MS analyses of sulfides at Macquarie University was provided by RYC-2015-17596. Minerals Targeting International Pty Ltd is acknowledged for providing directions regarding suitable sample sites for gold-bearing xenoliths. S.T. thanks CONICYT 21170857 for providing support through a PhD scholarship

    Dietary garlic and hip osteoarthritis: evidence of a protective effect and putative mechanism of action

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    Background Patterns of food intake and prevalent osteoarthritis of the hand, hip, and knee were studied using the twin design to limit the effect of confounding factors. Compounds found in associated food groups were further studied in vitro. Methods Cross-sectional study conducted in a large population-based volunteer cohort of twins. Food intake was evaluated using the Food Frequency Questionnaire; OA was determined using plain radiographs. Analyses were adjusted for age, BMI and physical activity. Subsequent in vitro studies examined the effects of allium-derived compounds on the expression of matrix-degrading proteases in SW1353 chondrosarcoma cells. Results Data were available, depending on phenotype, for 654-1082 of 1086 female twins (median age 58.9 years; range 46-77). Trends in dietary analysis revealed a specific pattern of dietary intake, that high in fruit and vegetables, showed an inverse association with hip OA (p = 0.022). Consumption of 'non-citrus fruit' (p = 0.015) and 'alliums' (p = 0.029) had the strongest protective effect. Alliums contain diallyl disulphide which was shown to abrogate cytokine-induced matrix metalloproteinase expression. Conclusions Studies of diet are notorious for their confounding by lifestyle effects. While taking account of BMI, the data show an independent effect of a diet high in fruit and vegetables, suggesting it to be protective against radiographic hip OA. Furthermore, diallyl disulphide, a compound found in garlic and other alliums, represses the expression of matrix-degrading proteases in chondrocyte-like cells, providing a potential mechanism of action
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