155 research outputs found

    Characteristics of cloud fraction from whole-sky camera and ceilometer observations onboard R/V Shirase during JARE 60

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    The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / Entrance Hall (1st floor) , National Institute of Polar Researc

    Efficient generation of nitrogen-vacancy center inside diamond with shortening of laser pulse duration

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    We investigated the effect of laser pulse duration on nitrogen-vacancy (NV) center generation inside a single crystal diamond. We compared pulse durations of 40 fs (femtosecond laser) and 1 ps (picosecond laser). We found that in both cases, ensemble NV centers could be generated inside the diamond. However, the maximum photoluminescence intensity of the NV center without graphitization for the 40 fs duration was higher than that for the 1 ps duration. This indicated that the femtosecond laser was harder to graphitize diamond and could generate more NV centers without graphitization. This difference may be due to the difference in the photo-absorption process and the resulting lattice dynamics

    Amyloid β aggregation induces human brain microvascular endothelial cell death with abnormal actin organization

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    Cerebral amyloid angiopathy (CAA) is a disease in which amyloid β (Aβ) is deposited on the walls of blood vessels in the brain, making those walls brittle and causing cerebral hemorrhage. However, the mechanism underlying its onset is not well understood. The aggregation and accumulation of Aβ cause the occlusion and fragility of blood vessels due to endothelial cell damage, breakdown of the blood-brain barrier, and replacement with elements constituting the blood vessel wall. In this study, we observed the effect of Aβ on human primary brain microvascular endothelial cells (hBMECs) in real-time using quantum dot nanoprobes to elucidate the mechanism of vascular weakening by Aβ. It was observed that Aβ began to aggregate around hBMECs after the start of incubation and that the cells were covered with aggregates. Aβ aggregates firmly anchored the cells on the plate surface, and eventually suppressed cell motility and caused cell death. Furthermore, Aβ aggregation induced the organization of abnormal actin, resulting in a significant increase in intracellular actin dots over 10 μm2. These results suggest that the mechanism by which Aβ forms a fragile vessel wall is as follows: Aβ aggregation around vascular endothelial cells anchors them to the substrate, induces abnormal actin organization, and leads to cell death

    Monthly Precipitation Collected at Hirosaki, Japan: Its Tritium Concentration and Chemical and Stable Isotope Compositions

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    Monthly precipitation samples were collected at Hirosaki, Aomori Prefecture from January 2018 to December 2020 to measure the ion species and stable hydrogen and oxygen isotope ratios in order to understand the regional properties. The tritium concentration ranged from 0.28 to 1.20 Bq/L, with mean values (±S.D.) of 0.52 ± 0.18, 0.67 ± 0.25 and 0.63 ± 0.21 Bq/L in 2018, 2019 and 2020, respectively. This concentration level was almost the same as for Rokkasho, Aomori Prefecture. The tritium concentration had clear seasonal variation: high in the spring and low in the summer. This trend was thought to arise from seasonal fluctuations in the atmospheric circulation. On the other hand, the pH tended to be low, and the electrical conductivity (EC) tended to be high from the winter to the spring. The ion components, which major ion species contained in sea salt, also tended to be high in the winter, and these components had a strong influence on EC. The d-excess values were high in the winter and low in the summer, and when this trend was considered from the viewpoint of the wind direction data in Hirosaki, these dust components were attributed to the northwest monsoon in the winter to the spring coming from the Asian continent

    TRITIUM, HYDROGEN AND OXYGEN ISOTOPE COMPOSITIONS IN MONTHLY PRECIPITATION SAMPLES COLLECTED AT TOKI, JAPAN

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    Monthly precipitation samples have been collected at Toki, Japan, from November 2013 to March 2017. In this report, selected data were analysed to identify the regional hydrogen and oxygen isotope compositions. Tritium (3H) concentration in the precipitation ranged from 0.10 to 0.61 Bq L−1 and higher 3H concentrations were observed in spring rather than in other seasons. This range was similar to values reported in Chiba City, Japan. 3H concentration and the ratio d-excess, and δD values were roughly clustered according to each separate season. These regional hydrogen and oxygen isotope compositions will be used for environmental assessments of effects of the deuterium plasma experiments of the large fusion test device

    The effects of perioperative oral management on perioperative serum albumin levels in patients treated surgically under general anesthesia : A multicenter retrospective analysis in Japan

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    The purpose of the present study was to investigate the efficacy of perioperative oral managements (POMs) on perioperative nutritional conditions in patients undergoing surgery with general anesthesia. Medical records were retrospectively reviewed and the effects of POMs were investigated based on a large number of cases using a multicenter analysis. The profile of serum albumin levels was assessed and compared between patients with and without POMs using the multivariate analysis. Seventeen Eleven thousand and one hundred sixty patients (4,873 males and 6,287 females) were reviewed. Of these, 2710 patients (24.3%) had undergone POMs. The results of a multivariate analysis revealed the significant positive effect of POMs on perioperative serum albumin level (change between at admission and discharge, (Estimate: 0.022, standard error: 0.012, P < .0001). Patient gender, age, surgical site, performance status, the American Society of Anesthesiologists (ASA) physical status classification, operation time, amount of blood loss, and serum albumin level at admission were also significant predictors. Adjusted multivariate analysis of the effects of POMs on perioperative change of serum albumin level in all subjects reveled the significance of POMs intervention (estimate: 0.022, standard error: 0.012, P < .0001). These results suggest that POMs exerts significant positive effects on perioperative serum albumin levels in patients underwent surgery under general anesthesia

    Autoimmune Pancreatitis Exhibiting Multiple Mass Lesions

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    Our case is a first report of autoimmune pancreatitis with multiple masses within the pancreas which was pathologically diagnosed by endoscopic ultrasound-guided fine needle aspiration and treated by steroid. The masses disappeared by steroid therapy. Our case is informative to know that autoimmune pancreatitis sometimes exhibits multiple masses within the pancreas and to diagnose it without unnecessary surgery

    Active auroral arc powered by accelerated electrons from very high altitudes

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    オーロラ粒子の加速領域が超高高度まで広がっていたことを解明 -オーロラ粒子の加速の定説を覆す発見-. 京都大学プレスリリース. 2021-01-20.Bright, discrete, thin auroral arcs are a typical form of auroras in nightside polar regions. Their light is produced by magnetospheric electrons, accelerated downward to obtain energies of several kilo electron volts by a quasi-static electric field. These electrons collide with and excite thermosphere atoms to higher energy states at altitude of ~ 100 km; relaxation from these states produces the auroral light. The electric potential accelerating the aurora-producing electrons has been reported to lie immediately above the ionosphere, at a few altitudes of thousand kilometres1. However, the highest altitude at which the precipitating electron is accelerated by the parallel potential drop is still unclear. Here, we show that active auroral arcs are powered by electrons accelerated at altitudes reaching greater than 30, 000 km. We employ high-angular resolution electron observations achieved by the Arase satellite in the magnetosphere and optical observations of the aurora from a ground-based all-sky imager. Our observations of electron properties and dynamics resemble those of electron potential acceleration reported from low-altitude satellites except that the acceleration region is much higher than previously assumed. This shows that the dominant auroral acceleration region can extend far above a few thousand kilometres, well within the magnetospheric plasma proper, suggesting formation of the acceleration region by some unknown magnetospheric mechanisms

    Prevalence of and risk factors for postoperative complications after lower third molar extraction : A multicenter prospective observational study in Japan

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    Lower third molar extraction is the most common surgical treatment among routine dental and oral surgical procedures. while the surgical procedures for lower third molar extraction are well established, the difficulty of tooth extraction and the frequency of postoperative complications differ depending on the patient’s background. To establish a management protocol for the lower third molars, the prevalence of and risk factors for postoperative complications after lower third molar extraction were investigated in a large number of Japanese patients in a multicenter prospective study. During 6 consecutive months in 2020, 1826 lower third molar extractions were performed at the 20 participating institutions. The medical records of the patients were reviewed, and relevant data were extracted. The prevalence of and risk factors for postoperative complications were analyzed. The prevalence of postoperative complications after lower third molar extraction was 10.0%. Multivariate analysis indicated that age (≤32 vs >32, odds ratio [OR]: 1.428, 95% confidence interval [95% CI]: 1.040–1.962, P < .05), the radiographic anatomical relationship between the tooth roots and mandibular canal (overlapping of the roots and canal vs no close anatomical relationship between the roots and the superior border of the canal, OR: 2.078, 95% CI: 1.333–3.238, P < .01; overlapping of the roots and canal vs roots impinging on the superior border of the canal, OR: 1.599, 95% CI: 1.050–2.435, P < .05), and impaction depth according to the Pell and Gregory classification (position C vs position A, OR: 3.7622, 95% CI: 2.079–6.310, P < .001; position C vs position B, OR: 2.574, 95% CI: 1.574–4.210, P < .001) are significant independent risk factors for postoperative complications after lower third molar extraction. These results suggested that higher age and a deeply impacted tooth might be significant independent risk factors for postoperative complications after lower third molar extraction
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