49 research outputs found

    Reconstruction of quark mass matrices in the NNI form from the experimental data

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    We examined the question that what is a general form of quark mass matrices which is achieved by the transformation that leaves the left-handed gauge interaction invariant. In particular, we analyzed in detail the Fritzsch-type and the Branco-Silva-Marcos-type parametrization. Both parametrizations contain ten parameters and can be expressed by the experimental data. We explicitly reconstructed quark mass matrices in terms of quark masses and CKM parameters for the Fritzsch-type parametrization.Comment: 17 pages and 4 figure

    Quantum effects for the neutrino mixing matrix in the democratic-type model

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    We investigate the quantum effects for the democratic-type neutrino mass matrix given at the right-handed neutrino mass scale mRm_R in order to see (i) whether θ23=−π/4\theta_{23}=-\pi/4 predicted by the model is stable to explain the atmospheric neutrino anomaly, (ii) how θ12\theta_{12} and θ13\theta_{13} behave, and (iii) whether the predicted Dirac CP phase δ\delta keeps maximal size, at the weak scale mZm_Z. We find that, for the (inversely) hierarchical mass spectrum with m1∼m2m_1\sim m_2, θ23\theta_{23} and θ13\theta_{13} are stable, while θ12\theta_{12} is not so, which leads to the possibility that the solar neutrino mixing angle can become large at mZm_Z even if it is taken small at mRm_R. We also show that δ\delta keeps almost maximal for the above mass spectrum, and our model can give the large CP violation effect in the future neutrino oscillation experiments if the solar neutrino puzzle is explained by the large mixing angle MSW solution.Comment: LaTeX, 21 pages, 2 figures, some mistakes correcte

    DNA methylation status of nuclear-encoded mitochondrial genes underlies the tissue-dependent mitochondrial functions

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    <p>Abstract</p> <p>Background</p> <p>Mitochondria are semi-autonomous, semi-self-replicating organelles harboring their own DNA (mitochondrial DNA, mtDNA), and their dysregulation is involved in the development of various diseases. While mtDNA does not generally undergo epigenetic modifications, almost all mitochondrial proteins are encoded by nuclear DNA. However, the epigenetic regulation of nuclear-encoded mitochondrial genes (nuclear mt genes) has not been comprehensively analyzed.</p> <p>Results</p> <p>We analyzed the DNA methylation status of 899 nuclear mt genes in the liver, brain, and heart tissues of mouse, and identified 636 nuclear mt genes carrying tissue-dependent and differentially methylated regions (T-DMRs). These nuclar mt genes are involved in various mitochondrial functions and they also include genes related to human diseases. T-DMRs regulate the expression of nuclear mt genes. Nuclear mt genes with tissue-specific hypomethylated T-DMRs were characterized by enrichment of the target genes of specific transcription factors such as FOXA2 in the liver, and CEBPA and STAT1 in the brain.</p> <p>Conclusions</p> <p>A substantial proportion of nuclear mt genes contained T-DMRs, and the DNA methylation status of numerous T-DMRs should underlie tissue-dependent mitochondrial functions.</p

    Unified Explanation of Quark and Lepton Masses and Mixings in the Supersymmetric SO(10) Model

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    We discussed neutrino masses and mixings in SUSY SO(10) model where quarks and leptons have Yukawa couplings to at least two 10 and one 126ˉ\bar{126} Higgs scalars. In this model, the Dirac and the right-handed Majorana mass terms are expressed by linear combinations of quark and charged lepton mass matrices, which then determine the neutrino mass matrix by the see-saw mechanism. We show that there are various solutions to reproduce a large mixing angle for νμ−ντ\nu_\mu-\nu_\tau and a small mixing angle for νe−νμ\nu_e-\nu_\mu, as well as the hierarchical mass spectrum of neutrinos.Comment: LaTeX, 32 pages including 15 eps figure

    ACPA-negative RA consists of two genetically distinct subsets based on RF positivity in Japanese.

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    HLA-DRB1, especially the shared epitope (SE), is strongly associated with rheumatoid arthritis (RA). However, recent studies have shown that SE is at most weakly associated with RA without anti-citrullinated peptide/protein antibody (ACPA). We have recently reported that ACPA-negative RA is associated with specific HLA-DRB1 alleles and diplotypes. Here, we attempted to detect genetically different subsets of ACPA-negative RA by classifying ACPA-negative RA patients into two groups based on their positivity for rheumatoid factor (RF). HLA-DRB1 genotyping data for totally 954 ACPA-negative RA patients and 2,008 healthy individuals in two independent sets were used. HLA-DRB1 allele and diplotype frequencies were compared among the ACPA-negative RF-positive RA patients, ACPA-negative RF-negative RA patients, and controls in each set. Combined results were also analyzed. A similar analysis was performed in 685 ACPA-positive RA patients classified according to their RF positivity. As a result, HLA-DRB1*04:05 and *09:01 showed strong associations with ACPA-negative RF-positive RA in the combined analysis (p = 8.8×10(-6) and 0.0011, OR: 1.57 (1.28-1.91) and 1.37 (1.13-1.65), respectively). We also found that HLA-DR14 and the HLA-DR8 homozygote were associated with ACPA-negative RF-negative RA (p = 0.00022 and 0.00013, OR: 1.52 (1.21-1.89) and 3.08 (1.68-5.64), respectively). These association tendencies were found in each set. On the contrary, we could not detect any significant differences between ACPA-positive RA subsets. As a conclusion, ACPA-negative RA includes two genetically distinct subsets according to RF positivity in Japan, which display different associations with HLA-DRB1. ACPA-negative RF-positive RA is strongly associated with HLA-DRB1*04:05 and *09:01. ACPA-negative RF-negative RA is associated with DR14 and the HLA-DR8 homozygote
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