408 research outputs found

    Pine Wood Crib Fires: Toxic Gas Emissions Using a 5m3 Compartment Fire

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    Toxic emissions from pinewood crib fires were determined using heated FTIR gas analysis from a 5 m3 compartment fire with an air opening equivalent to 5% of the compartment cross-sectional area (V2/3) in the floor of the compartment and a vent in the ceiling layer, with the air inlet controlling the flow. A 20 mm square pine wood crib size of 400 × 400 × 260 mm was investigated. The crib was ignited using a small ethanol pool fire. The flaming fire had a peak HRR of 40 kW and average ceiling temperature of 400 °C. The fire was lean overall at the peak HRR and the fire self-extinguished through lack of air with subsequent smouldering combustion. In spite of the lean combustion in the fire, very high toxic emissions were determined with an FEC LC50 of >6. The peak toxicity occurred just before the fire self-extinguished and the key toxic emissions were CO and formaldehyde for deaths, while formaldehyde and acrolein were the most important for impairment of escape

    Measurement of the proton form factor by studying e+eppˉe^{+} e^{-}\rightarrow p\bar{p}

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    Using data samples collected with the BESIII detector at the BEPCII collider, we measure the Born cross section of e+eppˉe^{+}e^{-}\rightarrow p\bar{p} at 12 center-of-mass energies from 2232.4 to 3671.0 MeV. The corresponding effective electromagnetic form factor of the proton is deduced under the assumption that the electric and magnetic form factors are equal (GE=GM)(|G_{E}|= |G_{M}|). In addition, the ratio of electric to magnetic form factors, GE/GM|G_{E}/G_{M}|, and GM|G_{M}| are extracted by fitting the polar angle distribution of the proton for the data samples with larger statistics, namely at s=\sqrt{s}= 2232.4 and 2400.0 MeV and a combined sample at s\sqrt{s} = 3050.0, 3060.0 and 3080.0 MeV, respectively. The measured cross sections are in agreement with recent results from BaBar, improving the overall uncertainty by about 30\%. The GE/GM|G_{E}/G_{M}| ratios are close to unity and consistent with BaBar results in the same q2q^{2} region, which indicates the data are consistent with the assumption that GE=GM|G_{E}|=|G_{M}| within uncertainties.Comment: 13 pages, 24 figure

    Observation of the isospin-violating decay J/ψϕπ0f0(980)J/\psi \to \phi\pi^{0}f_{0}(980)

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    Using a sample of 1.31 billion J/ψJ/\psi events collected with the BESIII detector at the BEPCII collider, the decays J/ψϕπ+ππ0J/\psi \to \phi \pi^{+}\pi^{-}\pi^{0} and J/ψϕπ0π0π0J/\psi \to \phi \pi^{0}\pi^{0}\pi^{0} are investigated. The isospin violating decay J/ψϕπ0f0(980)J/\psi \to \phi \pi^{0} f_{0}(980) with f0(980)ππf_{0}(980) \to \pi\pi, is observed for the first time. The width of the f0(980)f_{0}(980) obtained from the dipion mass spectrum is found to be much smaller than the world average value. In the π0f0(980)\pi^{0} f_{0}(980) mass spectrum, there is evidence of f1(1285)f_1(1285) production. By studying the decay J/ψϕηJ/\psi \to \phi\eta', the branching fractions of ηπ+ππ0\eta' \to \pi^{+}\pi^{-}\pi^{0} and ηπ0π0π0\eta' \to \pi^{0}\pi^{0}\pi^{0}, as well as their ratio, are also measured.Comment: 10 pages, 10 figures, published in Phys. Rev.

    An amplitude analysis of the π0π0\pi^{0}\pi^{0} system produced in radiative J/ψJ/\psi decays

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    An amplitude analysis of the π0π0\pi^{0}\pi^{0} system produced in radiative J/ψJ/\psi decays is presented. In particular, a piecewise function that describes the dynamics of the π0π0\pi^{0}\pi^{0} system is determined as a function of Mπ0π0M_{\pi^{0}\pi^{0}} from an analysis of the (1.311±0.011)×109(1.311\pm0.011)\times10^{9} J/ψJ/\psi decays collected by the BESIII detector. The goal of this analysis is to provide a description of the scalar and tensor components of the π0π0\pi^0\pi^0 system while making minimal assumptions about the properties or number of poles in the amplitude. Such a model-independent description allows one to integrate these results with other related results from complementary reactions in the development of phenomenological models, which can then be used to directly fit experimental data to obtain parameters of interest. The branching fraction of J/ψγπ0π0J/\psi \to \gamma \pi^{0}\pi^{0} is determined to be (1.15±0.05)×103(1.15\pm0.05)\times10^{-3}, where the uncertainty is systematic only and the statistical uncertainty is negligible.Comment: Submitted to Phys. Rev. D 19 pages, 4 figure

    Chromatin structure characteristics of pre-miRNA genomic sequences

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    <p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs) are non-coding RNAs with important roles in regulating gene expression. Recent studies indicate that transcription and cleavage of miRNA are coupled, and that chromatin structure may influence miRNA transcription. However, little is known about the relationship between the chromatin structure and cleavage of pre-miRNA from pri-miRNA.</p> <p>Results</p> <p>By analysis of genome-wide nucleosome positioning data sets from human and <it>Caenorhabditis elegans </it>(<it>C. elegans</it>), we found an enrichment of positioned nucleosome on pre-miRNA genomic sequences, which is highly correlated with GC content within pre-miRNA. In addition, obvious enrichments of three histone modifications (H2BK5me1, H3K36me3 and H4K20me1) as well as RNA Polymerase II (RNAPII) were observed on pre-miRNA genomic sequences corresponding to the active-promoter miRNAs and expressed miRNAs.</p> <p>Conclusion</p> <p>Our results revealed the chromatin structure characteristics of pre-miRNA genomic sequences, and implied potential mechanisms that can recognize these characteristics, thus improving pre-miRNA cleavage.</p

    Transient receptor potential canonical 4 and 5 proteins as targets in cancer therapeutics

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    Novel approaches towards cancer therapy are urgently needed. One approach might be to target ion channels mediating Ca²+ entry because of the critical roles played by Ca²+ in many cell types, including cancer cells. There are several types of these ion channels, but here we address those formed by assembly of transient receptor potential canonical (TRPC) proteins, particularly those which involve two closely related members of the family: TRPC4 and TRPC5. We focus on these proteins because recent studies point to roles in important aspects of cancer: drug resistance, transmission of drug resistance through extracellular vesicles, tumour vascularisation, and evoked cancer cell death by the TRPC4/5 channel activator (−)-englerin A. We conclude that further research is both justified and necessary before these proteins can be considered as strong targets for anti-cancer cell drug discovery programmes. It is nevertheless already apparent that inhibitors of the channels would be unlikely to cause significant adverse effects, but, rather, have other effects which may be beneficial in the context of cancer and chemotherapy, potentially including suppression of innate fear, visceral pain and pathological cardiac remodelling

    The prevalence of hyperuricemia in China: a meta-analysis

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    <p>Abstract</p> <p>Background</p> <p>The prevalence of hyperuricemia varied in different populations and it appeared to be increasing in the past decades. Recent studies suggest that hyperuricemia is an independent risk factor for cardiovascular disease. However, there has not yet been a systematic analysis of the prevalence of hyperuricemia in China.</p> <p>Methods</p> <p>Epidemiological investigations on hyperuricemia in China published in journals were identified manually and on-line by using CBMDISC, Chongqing VIP database and CNKI database. Those Reported in English journals were identified using MEDLINE database. Selected studies had to describe an original study defined by strict screening and diagnostic criteria. The fixed effects model or random effects model was employed according to statistical test for homogeneity.</p> <p>Results</p> <p>Fifty-nine studies were selected, the statistical information of which was collected for systematic analysis. The results showed that the pooled prevalence of hyperuricemia in male was 21.6% (95%CI: 18.9%-24.6%), but it was only 8.6% (95%CI: 8.2%-10.2%) in female. It was found that thirty years was the risk point age in male and it was fifty years in female.</p> <p>Conclusions</p> <p>The prevalence of hyperuricemia is different as the period of age and it increases after 30 years in male and 50 in female. Interventions are necessary to change the risk factors before the key age which is 30 years in male and 50 in female.</p
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