68 research outputs found

    Exciton scattering from impurities and acoustic phonons in carbon nanotubes

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    First Results of Axion Dark Matter Search with DANCE

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    Axions are one of the well-motivated candidates for dark matter, originally proposed to solve the strong CP problem in particle physics. Dark matter Axion search with riNg Cavity Experiment (DANCE) is a new experimental project to broadly search for axion dark matter in the mass range of 1017 eV<ma<1011 eV10^{-17}~\mathrm{eV} < m_a < 10^{-11}~\mathrm{eV}. We aim to detect the rotational oscillation of linearly polarized light caused by the axion-photon coupling with a bow-tie cavity. The first results of the prototype experiment, DANCE Act-1, are reported from a 24-hour observation. We found no evidence for axions and set 95% confidence level upper limit on the axion-photon coupling gaγ8×104 GeV1g_{a \gamma} \lesssim 8 \times 10^{-4}~\mathrm{GeV^{-1}} in 1014 eV<ma<1013 eV10^{-14}~\mathrm{eV} < m_a < 10^{-13}~\mathrm{eV}. Although the bound did not exceed the current best limits, this optical cavity experiment is the first demonstration of polarization-based axion dark matter search without any external magnetic field.Comment: 9 pages, 8 figure

    A Case of Chronic Thromboembolic Pulmonary Hypertension Secondary to Myeloproliferative Disease

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    A woman in her 60s presented with shortness of breath on exertion and was admitted to a nearby hospital in March 200X. Contrast-enhanced computer tomography scan showed contrast defect images in the pulmonary artery and lower extremity vein. She was diagnosed with pulmonary embolism and deep venous thrombosis and anticoagulant therapy was started. At the same time, a blood test revealed an abnormal increased platelet count(740,000/μl), and she was diagnosed as myeloproliferative disease(primary myelofibrosis, JAK2 mutation +). We follow up with oral administration of a steroid because she had a low risk of primary myelofibrosis. However, the symptom had been lasting, she was admitted into our hospital for examining the origin of symptom and treatment. Cardiac echocardiography suggested the presence of pulmonary hypertension, and lung ventilation perfusion scintigraphy showed widespread wedge accumulation defect, depressed area in bilateral lungs, and ventilator blood flow mismatch. In cardiac catheterization, the mean pulmonary artery pressure was as high as 37mmHg. Per the test results, she was diagnosed chronic thromboembolic pulmonary hypertension(CTEPH)secondary to primary myelofibrosis. We proposed invasive treatment(pulmonary artery endarterectomy, balloon pulmonary arterioplasty), but she desired just oxygen administration and medication therapy. It is reported that CTEPH develops in an organized thrombus after acute pulmonary embolism, but the mechanism of that development has not been revealed. In this case with primary myelofibrosis, we consider that the decrease of pulmonary vascular bed is due to a blood cell disorder and vascular remodeling is due to an increase of vascular endothelial growth factor and platelet derived growth factor secreted by abnormal increased platelet contributed to elevation of pulmonary artery pressure

    The Japanese space gravitational wave antenna; DECIGO

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    DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. DECIGO is expected to open a new window of observation for gravitational wave astronomy especially between 0.1 Hz and 10 Hz, revealing various mysteries of the universe such as dark energy, formation mechanism of supermassive black holes, and inflation of the universe. The pre-conceptual design of DECIGO consists of three drag-free spacecraft, whose relative displacements are measured by a differential Fabry– Perot Michelson interferometer. We plan to launch two missions, DECIGO pathfinder and pre- DECIGO first and finally DECIGO in 2024

    Measurement of the CP Violation Parameter sin(2phi_1) in B^0_d Meson Decays

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    We present a measurement of the Standard Model CP violation parameter sin(2phi_1) based on a 10.5 fb^{-1} data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e+e- collider. One neutral B meson is reconstructed in the J/psi K_S, psi(2S) K_S, chi_{c1} K_S, eta_c K_S, J/psi K_L or J/psi pi^0 CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its charged particle decay products. From the asymmetry in the distribution of the time interval between the two B-meson decay points, we determine sin(2phi_1) = 0.58 +0.32-0.34 (stat) +0.09-0.10 (syst).Comment: LaTex, 13 pages, 3 figures, submitted to P.R.

    OMI-VT stormに対するカテーテルアブレーション

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    A 68-year-old woman with VT storm and frequent appropriate ICD therapy was referred for catheter ablation. Her past history was notable for aortic valve replacement by mechanical valve due to infectious endocarditis 17 years prior to presentation and left ventricular apical old myocardial infarction with unknown onset. At 67 years old, She admitted to the prior hospital due to ventricular tachycardia with LBBB and superior axis at heart rate of 210 per minutes. Administration of amiodarone and magnesium sulfate was ineffective and cardioversion of 200J was successfully terminated the tachycardia. Intra-cardiac defibrillator was implanted and the administration of amiodarone and mexiletine was started. 5 months after, she admitted to the hospital due to the frequent appropriate shock against the same ventricular tachycardia. Administration of lidocaine, sotalol, pilsicainide, and magnesium sulfate could not control the tachycardia and she was referred to our hospital for catheter ablation. During the first session, ventricular tachycardia was easily induced and electroanatomical mapping was performed both during tachycardia and during sinus rhythm. Late diastolic potential preceding the onset of QRS wave by 45ms was detected at the infero-septal side of the apical aneurysm. 7.5s of the RF energy application at this site could terminate the tachycardia and thereafter no ventricular tachycardia was induced. But after dose-reduction or cessation of some anti-arrhythmic drugs, ventricular tachycardia was recurred and second session was performed. This time, no ventricular tachycardia was induced, then we performed isthmus transection and core isolation against the apical aneurysm. Thereafter no ventricular tachycardia was occurred in spite of dose-reduction or cessation of some anti-arrhythmic drugs

    DOCK2 is involved in the host genetics and biology of severe COVID-19

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    「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target
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