309 research outputs found

    CIP-CSLR Scheme for Condensation and Evaporation Calculations of Water Droplets

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    We present a number-density advection based method designed to calculate the condensation and evaporation of water droplets. An Eulerian-in-radius discretization scheme is adopted, making the present model suitable for use in the spectral bin model for cloud microphysics. The advection equation is solved using the constrained interpolated profile-conservative Semi-Lagrangian with rational function (CIP-CLSR) scheme. In order to evaluate the present method based on the CIP-CSLR scheme, we have performed test calculations for a sequence of condensation and evaporation using the present method and conventional methods, and then compared the results. The comparisons have revealed the advantages of the present method in terms of numerical accuracy, numerical stability, conservation and computational cost

    Research and development of an electron beam focusing system for a high-brightness X-ray generator

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    In order to minimize the size of the X-ray source for a U-shaped rotating anticathode X-ray generator, the electron beam is focused over a short distance by a combined-function bending magnet. Simulation predicts that the beam brightness will reach almost 500 kW mm−2 for a 120 keV/75 mA beam

    Acid Dissociation Equilibrium and Singlet Molecular Oxygen Quantum Yield of Acetylated 6,8–Dithioguanosine in Aqueous Buffer Solution

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    2’,3’,5’–Tri–O–acetyl–6,8–dithioguanosine (taDTGuo) is a modified nucleoside of drug 6–thioguanine and further developed as a potential photochemotherapeutic agent due to its desirable properties of photosensitivity to UVA light and singlet molecular oxygen generation. The photochemical characteristics of taDTGuo under biological conditions (namely in aqueous solution) were intensively investigated by the steady–state absorption and emission, time–resolved near–infrared emission measurements, and quantum chemical calculations. taDTGuo was found to be held in sequential acid dissociation equilibria within pH 3.79–11.93. With the global fitting analysis of the absorption spectra at various pHs, two pKa values of the equilibria were determined to be 7.02 ± 0.01 and 9.79 ± 0.01. Quantum chemical calculations suggested that its mono– and di–anionic species in the ground state should be 1–imide anionic form (N1–taDTGuo–) and 1,7–di–imide anionic form (taDTGuo2–) respectively. taDTGuo generates singlet molecular oxygen effectively and has pH–dependent quantum yields. In conclusion, taDTGuo would be most useful as a potent agent for photochemotherapy under certain carcinomatous pH conditions

    Guideline-based Treatment of Glucocorticoid-induced Osteoporosis in Patients with Rheumatoid Arthritis: A Retrospective Study with the AORA Registry

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    Glucocorticoid-induced osteoporosis (GIOP) is one of the side effects associated with glucocorticoid (GC) therapy. In 2014, the Japanese Society for Bone and Mineral Research (JSBMR) provided new guidelines for the management and treatment of GIOP. The aim of the present study was to clarify the prevalence of patients with rheumatoid arthritis (RA) requiring treatment according to the new guidelines and to identify risk factors associated with lack of treatment in these patients. Patients in the 2018 Akita Orthopedic group on Rheumatoid Arthritis (AORA) database were enrolled. Of 2,234 patients with RA in the database, 683 (30.6%) met the 2014 JSBMR guideline treatment criteria, and 480 (70.3%) had been treated. The untreated group included a larger number of males, younger patients, and patients treated in clinics rather than hospital (p<0.001, p=0.015, and p<0.001, respectively). Multivariate analyses found that male sex, younger age, and clinic-based RA care were significant risk factors associated with lack of treatment (p<0.001, p=0.013, and p<0.001, respectively). Thus, male sex, younger age, and clinic-based care were identified as risk factor

    北極海最適航路探索システムのADSへの実装

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    第6回極域科学シンポジウム分野横断セッション:[IA] 急変する北極気候システム及びその全球的な影響の総合的解明―GRENE北極気候変動研究事業研究成果報告2015―11月19日(木) 国立極地研究所1階交流アトリウ

    北極域データアーカイブ

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    第6回極域科学シンポジウム分野横断セッション:[IA] 急変する北極気候システム及びその全球的な影響の総合的解明―GRENE北極気候変動研究事業研究成果報告2015―11月19日(木) 国立極地研究所1階交流アトリウ

    Contrast-enhanced CT- and MRI-based perfusion assessment for pulmonary diseases: basics and clinical applications

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    Assessment of regional pulmonary perfusion as well as nodule and tumor perfusions in various pulmonary diseases are currently performed by means of nuclear medicine studies requiring radioactive macroaggregates, dual-energy computed tomography (CT), and dynamic first-pass contrast-enhanced perfusion CT techniques and unenhanced and dynamic first-pass contrast enhanced perfusion magnetic resonance imaging (MRI), as well as time-resolved three-dimensional or four-dimensional contrast-enhanced magnetic resonance angiography (MRA). Perfusion scintigraphy, single-photon emission tomography (SPECT) and SPECT fused with CT have been established as clinically available scintigraphic methods; however, they are limited by perfusion information with poor spatial resolution and other shortcomings. Although positron emission tomography with 15O water can measure absolute pulmonary perfusion, it requires a cyclotron for generation of a tracer with an extremely short half-life (2 min), and can only be performed for academic purposes. Therefore, clinicians are concentrating their efforts on the application of CT-based and MRI-based quantitative and qualitative perfusion assessment to various pulmonary diseases. This review article covers 1) the basics of dual-energy CT and dynamic first-pass contrast-enhanced perfusion CT techniques, 2) the basics of time-resolved contrast-enhanced MRA and dynamic first-pass contrast-enhanced perfusion MRI, and 3) clinical applications of contrast-enhanced CT- and MRI-based perfusion assessment for patients with pulmonary nodule, lung cancer, and pulmonary vascular diseases. We believe that these new techniques can be useful in routine clinical practice for not only thoracic oncology patients, but also patients with different pulmonary vascular diseases
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