160 research outputs found

    High sensitive X-ray films to detect electron showers in 100 GeV region

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    Nonscreen type X-ray films were used in emulsion chamber experiments to detect high energy showers in cosmic rays. Ranges of the detection threshold is from about 1 to 2 TeV depending on the exposure conditions. Different types of X-ray films and sheets i.e. high sensitive screen type X-ray films and luminescence sheets were tested. The threshold of the shower detection is found to be about 200 GeV, which is much lower than that of nonscreen type X-ray films. These films are useful to detect showers in the medium energy range, a few hundred GeV, of the cosmic ray electrons

    High energy electrons beyond 100 GEV observed by emulsion chamber

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    Much efforts have been expended to observe the spectrum of electrons in the high energy region with large area emulsion chambers exposed at balloon altitudes, and now 15 electrons beyond 1 TeV have been observed. The observed integral flux at 1 TeV is (3.24 + or - 0.87)x10(-5)/sq m sec sr. The statistics of the data around a few hundred GeV are also improving by using new shower detecting films of high sensitivity. The astrophysical significance of the observed spectrum are discussed for the propagation of electrons based on the leaky box and the nested leaky box model

    An Association Analysis between Mitochondrial DNA A10398G Polymorphism and Temperament in Japanese Young Adults

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    The mitochondrial (mt) DNA C5178A and A10398G polymorphisms have been reported to be associated with mental disorders such as bipolar disorder. However, the effects of these polymorphisms on temperament in healthy people are poorly understood. Evaluating healthy subjects can have the advantage of providing new strategies for maintaining psychological health and preventing mental illness. We examined the association between mtDNA polymorphisms and temperament in Japanese students. There was no significant difference in examined temperament when analysed by genotypes, 5178–10398 haplotypes, or sex. The subgroup analysis based on sex indicated that there was an interactive effect of the mtDNA A10398G polymorphism and sex on anxiety and obsession. This finding is preliminary and cannot exclude the possibility of false-positive due to small sample size (144 subjects) and multiple statistical testing. Further studies involving a larger sample size or other ethnic groups are necessary to confirm that mtDNA A10398G polymorphism can be a genetic factor for temperament

    Identification of phenolic constituents of cytisus multiflorus

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    The phenolic composition of the ethanolic extract obtained from the flowers of the medicinal plant Cytisus multiflorus has been elucidated by high performance liquid chromatography, electrospray mass spectrometry and nuclear magnetic resonance analysis. The extract was mainly composed of flavones, including the common chrysin, orientin, luteolin-5-O-glucoside, luteolin-7-O-glucoside, apigenin and apigenin-7-O-glucoside, which appeared as minor components. The major flavone in the extract was chrysin-7-O-B-D-glucopyranoside, and it also contained moderate amounts of a dihydroxyflavone isomer of chrysin, as well as of 2''-O-pentosyl-6-C-hexosyl-luteolin, 2''-O-pentosyl-8-C-hexosyl-luteolin and 6''- O-(3-hydroxy-3-methylglutaroyl)-2''-O-pentosyl-C-hexosyl-apigenin, which are not commonly found in the Fabaceae family. Other novel phenolic compounds found in the ethanolic extract of C. multiflorus comprised the flavones 2''-O-pentosyl-6-C-hexosyl-apigenin, 2''-O-pentosyl-8-C-hexosyl-apigenin and 6''-O-(3-hydroxy-3-methylglutaroyl)-200-O-pentosyl-C-hexosyl-luteolin. The assessment of the biological activities of the main compounds of this extract are now keen, in order to determine their relevance in the beneficial properties of the plant

    Ancient mtDNA Genetic Variants Modulate mtDNA Transcription and Replication

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    Although the functional consequences of mitochondrial DNA (mtDNA) genetic backgrounds (haplotypes, haplogroups) have been demonstrated by both disease association studies and cell culture experiments, it is not clear which of the mutations within the haplogroup carry functional implications and which are “evolutionary silent hitchhikers”. We set forth to study the functionality of haplogroup-defining mutations within the mtDNA transcription/replication regulatory region by in vitro transcription, hypothesizing that haplogroup-defining mutations occurring within regulatory motifs of mtDNA could affect these processes. We thus screened >2500 complete human mtDNAs representing all major populations worldwide for natural variation in experimentally established protein binding sites and regulatory regions comprising a total of 241 bp in each mtDNA. Our screen revealed 77/241 sites showing point mutations that could be divided into non-fixed (57/77, 74%) and haplogroup/sub-haplogroup-defining changes (i.e., population fixed changes, 20/77, 26%). The variant defining Caucasian haplogroup J (C295T) increased the binding of TFAM (Electro Mobility Shift Assay) and the capacity of in vitro L-strand transcription, especially of a shorter transcript that maps immediately upstream of conserved sequence block 1 (CSB1), a region associated with RNA priming of mtDNA replication. Consistent with this finding, cybrids (i.e., cells sharing the same nuclear genetic background but differing in their mtDNA backgrounds) harboring haplogroup J mtDNA had a >2 fold increase in mtDNA copy number, as compared to cybrids containing haplogroup H, with no apparent differences in steady state levels of mtDNA-encoded transcripts. Hence, a haplogroup J regulatory region mutation affects mtDNA replication or stability, which may partially account for the phenotypic impact of this haplogroup. Our analysis thus demonstrates, for the first time, the functional impact of particular mtDNA haplogroup-defining control region mutations, paving the path towards assessing the functionality of both fixed and un-fixed genetic variants in the mitochondrial genome

    MtSNPscore: a combined evidence approach for assessing cumulative impact of mitochondrial variations in disease

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    Human mitochondrial DNA (mtDNA) variations have been implicated in a broad spectrum of diseases. With over 3000 mtDNA variations reported across databases, establishing pathogenicity of variations in mtDNA is a major challenge. We have designed and developed a comprehensive weighted scoring system (MtSNPscore) for identification of mtDNA variations that can impact pathogenicity and would likely be associated with disease. The criteria for pathogenicity include information available in the literature, predictions made by various in silico tools and frequency of variation in normal and patient datasets. The scoring scheme also assigns scores to patients and normal individuals to estimate the cumulative impact of variations. The method has been implemented in an automated pipeline and has been tested on Indian ataxia dataset (92 individuals), sequenced in this study, and other publicly available mtSNP dataset comprising of 576 mitochondrial genomes of Japanese individuals from six different groups, namely, patients with Parkinson's disease, patients with Alzheimer's disease, young obese males, young non-obese males, and type-2 diabetes patients with or without severe vascular involvement. MtSNPscore, for analysis can extract information from variation data or from mitochondrial DNA sequences. It has a web-interface http://bioinformatics.ccmb.res.in/cgi-bin/snpscore/Mtsnpscore.pl webcite that provides flexibility to update/modify the parameters for estimating pathogenicity

    Measurement of B(D_s+ -> mu+ nu_mu)/B(D_s+ -> phi mu+ nu_mu) and Determination of the Decay Constant f_{D_s}

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    We have observed 23.2±6.00.9+1.023.2 \pm 6.0_{-0.9}^{+1.0} purely-leptonic decays of Ds+>μ+νμD_s^+ -> \mu^+ \nu_\mu from a sample of muonic one prong decay events detected in the emulsion target of Fermilab experiment E653. Using the Ds+>ϕμ+νμD_s^+ -> \phi \mu^+ \nu_\mu yield measured previously in this experiment, we obtain B(Ds+>μ+νμ)/B(Ds+>ϕμ+νμ)=0.16±0.06±0.03B(D_s^+ --> \mu^+ \nu_\mu) / B(D_s^+ --> \phi \mu^+ \nu_\mu) =0.16 \pm 0.06 \pm 0.03. In addition, we extract the decay constant fDs=194±35±20±14MeVf_{D_s}=194 \pm 35 \pm 20 \pm 14 MeV.Comment: 15 pages including one figur

    Observation of weak neutral current neutrino production of J/ψJ/\psi

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    Observation of \jpsi production by neutrinos in the calorimeter of the CHORUS detector exposed to the CERN SPS wide-band \numu beam is reported. A spectrum-averaged cross-section σJ/ψ\sigma^{\mathrm{J/\psi}} = (6.3 ±\pm 3.0) ×1041 cm2\times \mathrm{10^{-41}~cm^{2}} is obtained for 20 GeV Eν\leq E_{\nu} \leq 200 GeV. The data are compared with the theoretical model based on the QCD Z-gluon fusion mechanism

    Inferring the Population Expansions in Peopling of Japan

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    Background: Extensive studies in different fields have been performed to reconstruct the prehistory of populations in the Japanese archipelago. Estimates the ancestral population dynamics based on Japanese molecular sequences can extend our understanding about the colonization of Japan and the ethnogenesis of modern Japanese. Methodology/Principal Findings: We applied Bayesian skyline plot (BSP) with a dataset based on 952 Japanese mitochondrial DNA (mtDNA) genomes to depict the female effective population size (Nef) through time for the total Japanese and each of the major mtDNA haplogroups in Japanese. Our results revealed a rapid N ef growth since,5 thousand years ago had left,72 % Japanese mtDNA lineages with a salient signature. The BSP for the major mtDNA haplogroups indicated some different demographic history. Conclusions/Significance: The results suggested that the rapid population expansion acted as a major force in shaping current maternal pool of Japanese. It supported a model for population dynamics in Japan in which the prehistoric population growth initiated in the Middle Jomon Period experienced a smooth and swift transition from Jomon to Yayoi, and then continued through the Yayoi Period. The confounding demographic backgrounds of different mtDN
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