455 research outputs found

    Non-Abelian Discrete Symmetries in Particle Physics

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    We review pedagogically non-Abelian discrete groups, which play an important role in the particle physics. We show group-theoretical aspects for many concrete groups, such as representations, their tensor products. We explain how to derive, conjugacy classes, characters, representations, and tensor products for these groups (with a finite number). We discussed them explicitly for SNS_N, ANA_N, T′T', DND_N, QNQ_N, Σ(2N2)\Sigma(2N^2), Δ(3N2)\Delta(3N^2), T7T_7, Σ(3N3)\Sigma(3N^3) and Δ(6N2)\Delta(6N^2), which have been applied for model building in the particle physics. We also present typical flavor models by using A4A_4, S4S_4, and Δ(54)\Delta (54) groups. Breaking patterns of discrete groups and decompositions of multiplets are important for applications of the non-Abelian discrete symmetry. We discuss these breaking patterns of the non-Abelian discrete group, which are a powerful tool for model buildings. We also review briefly about anomalies of non-Abelian discrete symmetries by using the path integral approach.Comment: 179 pages, 8 figures, section 15 is changed, some references are adde

    Intact survival from severe cardiogenic shock caused by the first attack of atrial tachycardia treated with extracorporeal membrane oxygenation and surgical left atrium appendage resection: a case report

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    Background Atrial tachycardia (AT) is rare in children and can usually be reversed to sinus rhythm with pharmacotherapy and cardioversion. We report a rare case of severe left-sided heart failure due to refractory AT. Case presentation A 12-year-old boy had AT with a heart rate of 180 beats/minute, which was refractory to any medication and defibrillation despite the first attack. Due to rapid cardiorespiratory collapse shortly after arriving at our hospital, central extracorporeal membrane oxygenation (ECMO) with left arterial venting was started immediately. Although AT persisted after that, it stopped on the 3rd day after admission following surgical resection of the left atrial appendage thought to be the source of AT. He was weaned off ECMO on the 7th day and ventilator on the 14th day. Conclusions The appropriate timing of central ECMO and surgical ablation were effective in saving this child from a life-threatening situation caused by refractory AT

    Temporary hypotension and ventilation difficulty during endoscopic injection sclerotherapy for esophageal varices in a child with Fontan circulation: a case report

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    Background : Endoscopic procedures are rarely performed in children with congenital heart disease (CHD); therefore, the associated complications are unknown. We report an abrupt change in circulatory and respiratory condition during endoscopic injection sclerotherapy for esophageal varices. Case presentation : A 9-year-old boy with a history of total anomalous pulmonary venous connection (TAPVC) repair and Fontan procedure for asplenia and a single ventricle with TAPVC underwent endoscopic injection sclerotherapy under general anesthesia for esophageal varices. Systolic blood pressure decreased from 70 to 50 mmHg following a sclerosant injection; a second injection reduced his peripheral oxygen saturation from 93 to 79% secondary to ventilation difficulty. Although we suspected anaphylaxis intraoperatively, postoperative imaging suggested that balloon dilation performed to prevent sclerosing agent leakage caused compression of the pulmonary venous chamber and trachea owing to the anomalous intrathoracic organ anatomy. Conclusion : Thorough understanding of the complex anatomy is important before performing endoscopic procedures in children with CHD to preoperatively anticipate possible intraoperative complications and select the optimal therapeutic approach and anesthesia management

    An initio calculations for defects in silicon-based amorphous semiconductors

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    We have calclulated the ESR hyperfine parameters of threefold-coordinated Si atoms and twofold-coordinated P and N atoms in Si-based amorphous semiconductors using the density functional theory with a local-spin-density approximation. These calculated results have been compared with the observed ESR results

    Energy Bands and Their Pressure Dependence of Diamond- and Zincblende-type Crystals by Molecular Orbital Method

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    Electoronic structure of twofold-coordinated atoms in silicon-based amorphous semiconductors

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    Electronic states of the twofold-coordinated N atom in a-SixNi1-x:H and twofold-coordinated P atom in P-doped a-Si:H have been calculated using the density-functional theory with a local-spin-density approximation. The calculated 14N hyperfine parameters agree fairly well with those observed in N-rich a-SixN1-x:H by electron-spin-resonance (ESR) experiments, confirming the ESR center to be a twofold-coordinated N atom. On the other hand, the calculated 31P hyperfine parameters are largely different from the observed values for the ESR center with a 250-G splitting in P-doped a-Si:H. Therefore the ESR center should not be identified as a twofold-coordinated P atom

    Origin of the ESR signal with g=2.0055 in amorphous silicon

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    Defect-state wave functions for threefold- and fivefold-coordinated Si atoms in amorphous silicon clusters have been calculated with use of a first-principles linear combination of the atomic orbitals method in order to clarify the origin of the ESR signal with g=2.0055 in amorphous silicon. The wave function of the defect state originating from the threefold-coordinated Si atom is strongly localized on this atom. On the other hand, that for the fivefold-coordinated Si atom is extended on this atom and its nearest neighbors. By comparing these results with the observed hyperfine structure of the ESR signal, we conclude that the origin of this ESR signal is the threefold-coordinated Si atoms

    Changing Pattern of Deiminated Proteins in Developing Human Epidermis

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    Peptidylarginine deiminases are widely distributed, calcium-ion-dependent enzymes that convert arginine residues of proteins into citrulline residues. This reaction, deimination, is thought to be an important event during the final stage of epidermal differentiation, possibly associated with integration and disintegration of keratin filaments. To elucidate the possible roles of protein deimination during human epidermal development we investigated localization of deiminated proteins using anti-citrulline peptide antibody, which preferentially recognizes citrulline residues in the V subdomains of keratin 1, and anti-chemically modified citrulline antibody, which enables detection of citrulline residues independent of amino acid sequences. Anti-chemically modified citrulline antibody, but not anti-citrulline peptide antibody stained the periderm in two-layered epidermis of 49 d and 57 d estimated gestational age. In the stratified epidermis of 88 d, 96 d, and 108 d estimated gestational age fetal skin, anti-citrulline peptide antibody and anti-chemically modified citrulline antibody staining was seen in the periderm and intermediate cell layers. After periderm cells regressed and keratinization began in the interfollicular epidermis, anti-citrulline peptide antibody and anti-chemically modified citrulline antibody were restricted to the cornified cell layers of the interfollicular epidermis, similar to the distribution patterns of that in adult epidermis. Postembedding immunoelectron microscopy showed anti-citrulline peptide antibody immunogold labeling over the cytoplasmic intermediate filament network in the periderm and the intermediate cell layers. These results demonstrate an orderly formation of deiminated proteins in different layers of embryonic epidermis and suggest important roles for peptidylarginine deiminases in human epidermal morphogenesis
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