2,444 research outputs found

    Oleic Acid Protects Caenorhabditis Mothers From Mating-Induced Death and the Cost of Reproduction

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    Reproduction comes at a cost, including accelerated death. Previous studies of the interconnections between reproduction, lifespan, and fat metabolism in C. elegans were predominantly performed in low-reproduction conditions. To understand how increased reproduction affects lifespan and fat metabolism, we examined mated worms; we find that a Δ9 desaturase, FAT-7, is significantly up-regulated. Dietary supplementation of oleic acid (OA), the immediate downstream product of FAT-7 activity, restores fat storage and completely rescues mating-induced death, while other fatty acids cannot. OA-mediated lifespan restoration is also observed in C. elegans mutants suffering increased death from short-term mating, and in mated C. remanei females, indicating a conserved role of oleic acid in post-mating lifespan regulation. Our results suggest that increased reproduction can be uncoupled from the costs of reproduction from somatic longevity regulation if provided with the limiting lipid, oleic acid

    Carbon Monoxide Protects against Liver Failure through Nitric Oxide–induced Heme Oxygenase 1

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    Carbon monoxide (CO) and nitric oxide (NO) each have mechanistically unique roles in various inflammatory disorders. Although it is known that CO can induce production of NO and that NO can induce expression of the cytoprotective enzyme heme oxygenase 1 (HO-1), there is no information whether the protective effect of CO ever requires NO production or whether either gas must induce expression of HO-1 to exert its functional effects. Using in vitro and in vivo models of tumor necrosis factor α–induced hepatocyte cell death in mice, we find that activation of nuclear factor κB and increased expression of inducible NO are required for the protective effects of CO, whereas the protective effects of NO require up-regulation of HO-1 expression. When protection from cell death is initiated by CO, NO production and HO-1 activity are each required for the protective effect showing for the first time an essential synergy between these two molecules in tandem providing potent cytoprotection

    Precision Measurement of the Neutron Spin Asymmetry A1nA_1^n and Spin-Flavor Decomposition in the Valence Quark Region

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    We have measured the neutron spin asymmetry A1nA_1^n with high precision at three kinematics in the deep inelastic region at x=0.33x=0.33, 0.47 and 0.60, and Q2=2.7Q^2=2.7, 3.5 and 4.8 (GeV/c)2^2, respectively. Our results unambiguously show, for the first time, that A1nA_1^n crosses zero around x=0.47x=0.47 and becomes significantly positive at x=0.60x=0.60. Combined with the world proton data, polarized quark distributions were extracted. Our results, in general, agree with relativistic constituent quark models and with perturbative quantum chromodynamics (pQCD) analyses based on the earlier data. However they deviate from pQCD predictions based on hadron helicity conservation.Comment: 5 pages, 2 figures, this is the final version appeared in Phys. Rev. Let

    Precision Measurement of the Neutron Spin Asymmetries and Spin-dependent Structure Functions in the Valence Quark Region

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    We report on measurements of the neutron spin asymmetries A1,2nA_{1,2}^n and polarized structure functions g1,2ng_{1,2}^n at three kinematics in the deep inelastic region, with x=0.33x=0.33, 0.47 and 0.60 and Q2=2.7Q^2=2.7, 3.5 and 4.8 (GeV/c)2^2, respectively. These measurements were performed using a 5.7 GeV longitudinally-polarized electron beam and a polarized 3^3He target. The results for A1nA_1^n and g1ng_1^n at x=0.33x=0.33 are consistent with previous world data and, at the two higher xx points, have improved the precision of the world data by about an order of magnitude. The new A1nA_1^n data show a zero crossing around x=0.47x=0.47 and the value at x=0.60x=0.60 is significantly positive. These results agree with a next-to-leading order QCD analysis of previous world data. The trend of data at high xx agrees with constituent quark model predictions but disagrees with that from leading-order perturbative QCD (pQCD) assuming hadron helicity conservation. Results for A2nA_2^n and g2ng_2^n have a precision comparable to the best world data in this kinematic region. Combined with previous world data, the moment d2nd_2^n was evaluated and the new result has improved the precision of this quantity by about a factor of two. When combined with the world proton data, polarized quark distribution functions were extracted from the new g1n/F1ng_1^n/F_1^n values based on the quark parton model. While results for Δu/u\Delta u/u agree well with predictions from various models, results for Δd/d\Delta d/d disagree with the leading-order pQCD prediction when hadron helicity conservation is imposed.Comment: A typing error in A_\parallel(3He) at x=0.47 in Table VII of Phys. Rev. C has been noticed and correcte

    Precise measurement of the W-boson mass with the CDF II detector

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    We have measured the W-boson mass MW using data corresponding to 2.2/fb of integrated luminosity collected in proton-antiproton collisions at 1.96 TeV with the CDF II detector at the Fermilab Tevatron collider. Samples consisting of 470126 W->enu candidates and 624708 W->munu candidates yield the measurement MW = 80387 +- 12 (stat) +- 15 (syst) = 80387 +- 19 MeV. This is the most precise measurement of the W-boson mass to date and significantly exceeds the precision of all previous measurements combined

    Search for Neutral Higgs Bosons in Events with Multiple Bottom Quarks at the Tevatron

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    The combination of searches performed by the CDF and D0 collaborations at the Fermilab Tevatron Collider for neutral Higgs bosons produced in association with b quarks is reported. The data, corresponding to 2.6 fb-1 of integrated luminosity at CDF and 5.2 fb-1 at D0, have been collected in final states containing three or more b jets. Upper limits are set on the cross section multiplied by the branching ratio varying between 44 pb and 0.7 pb in the Higgs boson mass range 90 to 300 GeV, assuming production of a narrow scalar boson. Significant enhancements to the production of Higgs bosons can be found in theories beyond the standard model, for example in supersymmetry. The results are interpreted as upper limits in the parameter space of the minimal supersymmetric standard model in a benchmark scenario favoring this decay mode.Comment: 10 pages, 2 figure

    Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015

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    SummaryBackground The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation
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