1,023 research outputs found

    Signatures of the neutrino mass hierarchy in supernova neutrinos

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    The undetermined neutrino mass hierarchy may leave an observable imprint on the neutrino fluxes from a core-collapse supernova (SN). The interpretation of the observables, however, is subject to the uncertain SN models and the flavor conversion mechanism of neutrinos in a SN. We attempt to propose a qualitative interpretation of the expected neutrino events at terrestrial detectors, focusing on the accretion phase of the neutrino burst. The flavor conversions due to neutrino self-interaction, the MSW effect, and the Earth regeneration effect are incorporated in the calculation. It leads to several distinct scenarios that are identified by the neutrino mass hierarchies and the collective flavor transitions. Consequences resulting from the variation of incident angles and SN models are also discussed.Comment: 15 pages, 9 figure

    Working Hours Reduction and Endogenous Growth

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    This paper formulates an endogenous growth model and uses it to inquire into the long-run impact of work-sharing arrangements on economic growth. We show that the styles of wage contract, namely salary-style and hourly-style contracts, are a key factor in determining the long-run growth effects of working time reduction. If the labor market is overwhelmingly salaried arrangement, then the extent of wage flexibility is relatively low; as a consequence, a policy of reducing working hours will deteriorate economic growth. On the contrary, if hourly pay predominates, then the wage system tends to increase the degree of wage flexibility. Thus, a cut in working time may favor the economy’s growth rate.Working hours reduction, Endogenous growth

    Arsenic Exposure and Methylation Efficiency in Relation to Oxidative Stress in Semiconductor Workers

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    This study examined associations between oxidative stress and arsenic (As) exposure and methylation efficiency in semiconductor workers. An As-exposed group (n = 427) and a control group (n = 91) were included. The As-exposure group (n = 427) included 149 maintenance staff members and 278 production staff members representing high As exposure and low As exposure, respectively. The control group included 91 administrative staff members with no or minimal As exposure. An occupational exposure assessment was conducted to assess personal As exposure by measuring As concentrations in urine, hair, and fingernails of the subjects. Urinary As(III), As(V), monomethylarsonic (MMA), and dimethylarsinic acid (DMA) were quantified to assess an internal dose of inorganic As. Urinary 8-hydroxy-2’-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) were measured to asses oxidative DNA damage and lipid peroxidation, respectively. As concentrations in urine, hair, and fingernails significantly increased (p \u3c 0.05) in the As-exposed group in comparison to the control group. Geometric mean urinary concentrations of As, 8-OHdG, and MDA in the As-exposed group significantly exceeded those in the control group. As exposure to As-exposed workers had increased concentrations of 8-OHdG in contrast to those in control subjects. Moreover, urinary 8-OHdG concentrations in the semiconductor workers were positively correlated with urinary total As metabolite (As(III) + As(V) + MMA + DMA) concentrations. Furthermore, urinary excretion of 8-OHdG concentrations in As-exposed workers were positively associated with urinary excretion of MMA concentrations and primary methylation index values (the ration of MMA/inorganic As). However, fingernail and hair samples did not perform as well as urinary samples to measure oxidative stress induced by As exposure. 8-OHdG could serve as a more reliable biomarker for assessing As methylation than MDA did. Occupational exposure to inorganic As was associated with increased oxidative stress among semiconductor workers

    Intra-articular injections of sodium hyaluronate (HyalganÂŽ) in osteoarthritis of the knee. a randomized, controlled, double-blind, multicenter trial in the asian population

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    <p>Abstract</p> <p>Background</p> <p>The efficacy and tolerability of 500-730 kDa sodium hyaluronate (Hyalgan<sup>ÂŽ</sup>) for treatment of osteoarthritis (OA) pain has been established in clinical trials, but few data are available in the Asian population. We conducted a randomized, double-blind, multicenter, placebo-controlled study to evaluate the efficacy and tolerability of this preparation in a Taiwanese population.</p> <p>Methods</p> <p>Two hundred patients with mild to moderate OA of the knee were randomized to receive five weekly intra-articular injections of sodium hyaluronate or placebo. The primary efficacy outcome was the change from baseline to Week 25 in patients' evaluation of pain using a 100-mm visual analog scale (VAS) during the 50-foot walking test. Additional outcomes included Western Ontario and McMaster Universities (WOMAC) scores, time on the 50-foot walking test, patient's and investigator's subjective assessment of effectiveness, acetaminophen consumption, and the amounts of synovial fluid.</p> <p>Results</p> <p>The Hyalgan<sup>ÂŽ </sup>treatment group showed a significantly greater improvement from baseline to Week 25 in VAS pain on the 50-foot walking test than the placebo group (p = 0.0020). The Hyalgan<sup>ÂŽ </sup>group revealed significant improvements from baseline to week 25 in WOMAC pain and function score than the placebo group (p = 0.005 and 0.0038, respectively) Other outcomes, such as time on the 50-foot walking test and subjective assessment of effectiveness, did not show any significant difference between groups. Both groups were safe and well tolerated.</p> <p>Conclusions</p> <p>The present study suggests that five weekly intra-articular injections of sodium hyaluronate are well tolerated, can provide sustained relief of pain, and can improve function in Asian patients with osteoarthritis of the knee.</p> <p>Level of Evidence</p> <p>Therapeutic study, Level I-1a (randomized controlled trial with a significant difference).</p> <p>Trial registration</p> <p>ClinicalTrials.gov Identifier: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01319461">NCT01319461</a></p

    Motor neuron-derived Thsd7a is essential for zebrafish vascular development via the Notch-dll4 signaling pathway.

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    BackgroundDevelopment of neural and vascular systems displays astonishing similarities among vertebrates. This parallelism is under a precise control of complex guidance signals and neurovascular interactions. Previously, our group identified a highly conserved neural protein called thrombospondin type I domain containing 7A (THSD7A). Soluble THSD7A promoted and guided endothelial cell migration, tube formation and sprouting. In addition, we showed that thsd7a could be detected in the nervous system and was required for intersegmental vessels (ISV) patterning during zebrafish development. However, the exact origin of THSD7A and its effect on neurovascular interaction remains unclear.ResultsIn this study, we discovered that zebrafish thsd7a was expressed in the primary motor neurons. Knockdown of Thsd7a disrupted normal primary motor neuron formation and ISV sprouting in the Tg(kdr:EGFP/mnx1:TagRFP) double transgenic zebrafish. Interestingly, we found that Thsd7a morphants displayed distinct phenotypes that are very similar to the loss of Notch-delta like 4 (dll4) signaling. Transcript profiling further revealed that expression levels of notch1b and its downstream targets, vegfr2/3 and nrarpb, were down-regulated in the Thsd7a morphants. These data supported that zebrafish Thsd7a could regulate angiogenic sprouting via Notch-dll4 signaling during development.ConclusionsOur results suggested that motor neuron-derived Thsd7a plays a significant role in neurovascular interactions. Thsd7a could regulate ISV angiogenesis via Notch-dll4 signaling. Thus, Thsd7a is a potent angioneurin involved in the development of both neural and vascular systems

    Ceftriaxone attenuates hypoxic-ischemic brain injury in neonatal rats

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    <p>Abstract</p> <p>Background</p> <p>Perinatal brain injury is the leading cause of subsequent neurological disability in both term and preterm baby. Glutamate excitotoxicity is one of the major factors involved in perinatal hypoxic-ischemic encephalopathy (HIE). Glutamate transporter GLT1, expressed mainly in mature astrocytes, is the major glutamate transporter in the brain. HIE induced excessive glutamate release which is not reuptaked by immature astrocytes may induce neuronal damage. Compounds, such as ceftriaxone, that enhance the expression of GLT1 may exert neuroprotective effect in HIE.</p> <p>Methods</p> <p>We used a neonatal rat model of HIE by unilateral ligation of carotid artery and subsequent exposure to 8% oxygen for 2 hrs on postnatal day 7 (P7) rats. Neonatal rats were administered three dosages of an antibiotic, ceftriaxone, 48 hrs prior to experimental HIE. Neurobehavioral tests of treated rats were assessed. Brain sections from P14 rats were examined with Nissl and immunohistochemical stain, and TUNEL assay. GLT1 protein expression was evaluated by Western blot and immunohistochemistry.</p> <p>Results</p> <p>Pre-treatment with 200 mg/kg ceftriaxone significantly reduced the brain injury scores and apoptotic cells in the hippocampus, restored myelination in the external capsule of P14 rats, and improved the hypoxia-ischemia induced learning and memory deficit of P23-24 rats. GLT1 expression was observed in the cortical neurons of ceftriaxone treated rats.</p> <p>Conclusion</p> <p>These results suggest that pre-treatment of infants at risk for HIE with ceftriaxone may reduce subsequent brain injury.</p

    Impact of Heavy Metals in Ambient Air in Insulin Resistance of Shipyard Welders in Northern Taiwan

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    Exposure to metals poses potential health risks, including insulin resistance (IR), to those exposed to them in excess. Limited studies have examined such risks in occupational workers, including welders, and these have yielded inconsistent results. Thus, we examined the associations between exposure to welding metals and IR in welders. We recruited 78 welders and 75 administrative staff from a shipyard located in northern Taiwan. Personal exposure to heavy metals, including chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), and cadmium (Cd), was monitored through particulate matter with an aerodynamic diameter of less than 2.5 μm (PM2.5) and urine analysis by inductively coupled plasma mass spectrometry (ICP–MS). After each participant fasted overnight, blood samples were collected and analyzed for IR assessment through updated homeostasis model assessment (HOMA2) modeling. Air sampling in the personal breathing zone was performed during a Monday shift prior to the blood and urine sample collection the following morning. The welders’ median personal Cr, Mn, Fe, Ni, Cu, and Zn airborne PM2.5 levels and urinary Cd levels were significantly higher than those of the administrative staff. After adjustment for covariates, logarithmic PM2.5-Mn, PM2.5-Fe, PM2.5-Cu, and PM2.5-Zn levels were positively correlated with logarithmic fasting plasma glucose (P-FGAC) levels (PM2.5-Mn: β = 0.0105, 95% C.I.: 0.0027–0.0183; PM2.5-Fe: β = 0.0127, 95% C.I.: 0.0027–0.0227; PM2.5-Cu: β = 0.0193, 95% C.I.: 0.0032–0.0355; PM2.5-Zn: β = 0.0132, 95% C.I.: 0.0005–0.0260). Logarithmic urinary Zn was positively correlated with logarithmic serum insulin and HOMA2-IR levels and negatively correlated with logarithmic HOMA2-insulin sensitivity (%S; βinsulin = 0.2171, 95% C.I.: 0.0025–0.4318; βIR = 0.2179, 95% C.I.: 0.0027–0.4330; β%S = −0.2180, 95% C.I.: −0.4334 to −0.0026). We observed that glucose homeostasis was disrupted by Mn, Fe, Cu, and Zn exposure through increasing P-FGAC and IR levels in shipyard welders

    International R&D Funding and Patent Collateral in an R&D-Growth Model

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    This paper develops an R&D-based growth model featuring international R&D funding and patent collateral. It then uses the model to examine how the international borrowing interest rate and the fraction of patent collateral will affect innovations and economic growth

    Could Fiscal Policies Overcome a Deep Recession at the Zero Lower Bound?

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    This paper sets up a New Keynesian model in which the monetary authority implements a zero lower bound interest rate policy, and uses it to explore whether the supportive fiscal instruments (including expansionary government spending, a payroll tax cut, and a financial assets tax cut) are effective in overcoming a deep recession. The salient feature of this study is that it provides a new dynamic viewpoint of regime switching by evaluating each of several supportive fiscal policies in terms of their performance in alleviating a deep recession. Two main findings emerge from the analysis. First, when the monetary authority implements the zero lower bound interest rate policy to dampen the negative natural rate shock, the economy will sink into a deep recession with deflation. Second, to overcome the deep recession, of the three supportive fiscal tools (i.e., expansionary government spending, a payroll tax cut, and a financial assets tax cut), only expansionary government spending is effective in alleviating the deep recession. More specifically, the implementation of fiscal policy in the form of either the payroll tax cut or the financial assets tax cut will only further deepen the recession

    The Porcine Circovirus Type 2 Nonstructural Protein ORF3 Induces Apoptosis in Porcine Peripheral Blood Mononuclear Cells

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    Porcine circovirus type 2 (PCV2) is the primary causative agent of porcine circovirus-associated diseases in pigs. To analyze whether the PCV2 nonstructural protein ORF3 is able to induce apoptosis in nature target cells, transient expression of ORF3 in porcine peripheral blood mononuclear cells (PBMC) was performed, and apoptosis was confirmed by terminal dexoynucleotidyl transferase (TdT)-mediated BrdUTP-nick end labeling (TUNEL) assay. The apoptotic responses induced by the full length or the C-terminal half of ORF3 were significantly higher (p < 0.001) than that of cells transfected with the control plasmid. In contrast, the N-terminal half of ORF3 restrictively localized in the cytoplasm and remarkably reduced its ability to induce apoptosis, the apoptotic activity might be correlated with the nuclear localization of ORF3. Furthermore, two clusters of basic residues on the C-terminal half region at the amino acid residues 53-68 and 85-104 could mediate the nuclear localization of fusion protein, confirming their potential role as a nuclear localization signal
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