著者

Shogo NISHIYAMA Tomohiro KARA Brian THORSBRO Hiromi SAIDA Yohsuke TAKAMORI Masaaki TAKAHASHI Takayuki OHGAMI Kohei ICHIKAWA Rainer SCHÖDEL

出版者

The Japan Academy

雑誌

Proceedings of the Japan Academy, Series B (ISSN:03862208)

巻号頁・発行日

pp.pjab.100.007, (Released:2023-12-01)

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The tremendous tidal force that is linked to the supermassive black hole (SMBH) at the center of our galaxy is expected to strongly subdue star formation in its vicinity. Stars within 1'' from the SMBH thus likely formed further from the SMBH and migrated to their current positions. In this study, spectroscopic observations of the star S0-6/S10, one of the closest (projected distance from the SMBH of ≈0''.3) late-type stars were conducted. Using metal absorption lines in the spectra of S0-6, the radial velocity of S0-6 from 2014 to 2021 was measured, and a marginal acceleration was detected, which indicated that S0-6 is close to the SMBH. The S0-6 spectra were employed to determine its stellar parameters including temperature, chemical abundances ([M/H], [Fe/H], [α/Fe], [Ca/Fe], [Mg/Fe], [Ti/Fe]), and age. As suggested by the results of this study, S0-6 is very old (≳10 Gyr) and has an origin different from that of stars born in the central pc region.

著者

Hayahide Ooi Yuki Asai Yoshiki Koriyama Masaaki Takahashi

出版者

The Pharmaceutical Society of Japan

雑誌

Biological and Pharmaceutical Bulletin (ISSN:09186158)

巻号頁・発行日

vol.46, no.12, pp.1731-1736, 2023-12-01 (Released:2023-12-01)

参考文献数

20

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The albumin–bilirubin (ALBI) score is an index of hepatic functional reserve and is calculated from serum albumin and total bilirubin levels. However, the relationship between ceftriaxone (CTRX)-induced liver injury and ALBI score remains unknown. Therefore, we aimed to elucidate the risk of CTRX-induced liver injury based on the ALBI scores and CTRX dosage. This was a single-center, retrospective, case-control study of 490 patients and the primary outcome was CTRX-induced liver injury. We performed a COX regression analysis using age ≥75 years, male sex, alanine aminotransferase levels, ALBI score, and CTRX dosage regimen (4 ≥2 or 1 g/d) as explanatory factors. We also performed 1 : 1 propensity score matching between non-liver injury and liver injury groups. The incidence of liver injury was 10.0% (49/490). In COX regression analysis, CTRX 4 g/d was an independent risk factor for liver injury (95% coefficient interval: 1.05–6.96, p = 0.04). Meanwhile, ALBI score ≥−1.61 was an independent factor for liver injury (95% coefficient interval: 1.03–3.22, p = 0.04) with the explanatory factor of ≥2 and 1 g/d. The Kaplan–Meier curve indicated that the cumulative risk for CTRX-induced liver injury was significantly higher in the ALBI score ≥−1.61 group than in the ALBI score <−1.61 group before propensity score matching (p = 0.032); however, no significant differences were observed after propensity score matching (p = 0.791). These findings suggest that in patients treated with CTRX with ALBI score ≥−1.61, frequent liver function monitoring should be considered.

著者

Kei SAKAMOTO Masaaki TAKAHASHI

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.83, no.5, pp.817-834, 2005 (Released:2005-11-19)

参考文献数

16

被引用文献数

23 23

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Near the tropopause over the North Pacific in summer an isolated low pressure system (Upper Cold Low, UCL) is often generated by the deepening and cutting off of a trough in the mid-latitude westerlies. The tracks and structures of these UCLs have been investigated in previous studies, but understanding of the cut off and weakening processes remains poor. In this paper, the tracks of UCLs generated in the 1999 summer are analyzed using ECMWF data. The physical processes occurring in one ofthese systems are investigated in detail using the ECMWF data, and the meso-scale model MM5. We focus particularly on cut off and weakening processes, and on the structure of the vertical velocity in the UCL.The summer of 1999 was hot over Japan, and part of the Tibetan high pressure, around 200 hPa, was shifted northward. This allowed some UCLs to approach Japan in July and August. A UCL on August 19th is selected for detailed analysis, and was generated in the following process. Positive vorticity in a westerly wave at 200 hPa was extended by a northeast wind in the upper layer only. The positive vorticity was cut off by non-liner effects and upper level divergence, associated with convective clouds, generating the isolated UCL. The structure of the cyclonic circulation and the warm and cold cores were similar to those in previous studies. The structure of the vertical motion of the moving UCL was explained by dry dynamics and there was upward motion on the front side of the UCL, in the direction of movement. Upper level clouds in the UCL strengtJhened this upward motion. Convective clouds were seen in the system. The latent heat of these convective clouds played an important role in weakening the cold core of the UCL.

著者

Yousuke YAMASHITA Hideharu AKIYOSHI Theodore G. SHEPHERD Masaaki TAKAHASHI

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.93, no.6, pp.629-644, 2015 (Released:2016-01-13)

参考文献数

52

被引用文献数

7 9

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The combined influences of the westerly phase of the quasi-biennial oscillation (QBO-W) and solar maximum (Smax) conditions on the Northern Hemisphere extratropical winter circulation are investigated using reanalysis data and Center for Climate System Research/National Institute for Environmental Studies chemistry climate model (CCM) simulations. The composite analysis for the reanalysis data indicates strengthened polar vortex in December followed by weakened polar vortex in February-March for QBO-W during Smax (QBO-W/Smax) conditions. This relationship need not be specific to QBO-W/Smax conditions but may just require strengthened vortex in December, which is more likely under QBO-W/Smax. Both the reanalysis data and CCM simulations suggest that dynamical processes of planetary wave propagation and meridional circulation related to QBO-W around polar vortex in December are similar in character to those related to Smax; furthermore, both processes may work in concert to maintain stronger vortex during QBO-W/Smax. In the reanalysis data, the strengthened polar vortex in December is associated with the development of north-south dipole tropospheric anomaly in the Atlantic sector similar to the North Atlantic oscillation (NAO) during December-January. The structure of the north-south dipole anomaly has zonal wavenumber 1 (WN1) component, where the longitude of anomalous ridge overlaps with that of climatological ridge in the North Atlantic in January. This implies amplification of the WN1 wave and results in the enhancement of the upward WN1 propagation from troposphere into stratosphere in January, leading to the weakened polar vortex in February-March. Although WN2 waves do not play a direct role in forcing the stratospheric vortex evolution, their tropospheric response to QBO-W/Smax conditions appears to be related to the maintenance of the NAO-like anomaly in the high-latitude troposphere in January. These results may provide a possible explanation for the mechanisms underlying the seasonal evolution of wintertime polar vortex anomalies during QBO-W/Smax conditions and the role of troposphere in this evolution.

著者

高橋 正明 于 亜 Masaaki TAKAHASHI Ya YU

出版者

大手前女子大学

雑誌

大手前女子大学論集 = The Journal of Otemae Women's University (ISSN:02859785)

巻号頁・発行日

vol.30, pp.105-128, 1996-02-20

著者

高橋 正明 Masaaki TAKAHASHI

出版者

大手前女子大学

雑誌

大手前女子大学論集 = The Journal of Otemae Women's University (ISSN:02859785)

巻号頁・発行日

vol.28, pp.131-154, 1994-12-20

著者

KUNIAKI TATSUTA HIROSHI MUKAI MASAAKI TAKAHASHI

出版者

JAPAN ANTIBIOTICS RESEARCH ASSOCIATION

雑誌

The Journal of Antibiotics (ISSN:00218820)

巻号頁・発行日

vol.53, no.4, pp.430-435, 2000-04-25 (Released:2008-09-19)

参考文献数

14

被引用文献数

13 29

著者

Masaaki Takahashi Chie Yoshida Toshikazu Komoda

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.OKD-076, (Released:2017-06-10)

被引用文献数

5

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A light irradiation method was found to promote coloring in sweet pepper fruit (Capsicum annuum L.) harvested at the breaker stage of mature green fruit. In summer and autumn culture, heating systems are not usually used, and a large amount of uncolored fruit remains after harvest because of low temperatures and/or insufficient sunlight. We investigated the use of light irradiation to enhance the color of the fruit post-harvest and found that light intensities between 50 μmol·m−2·s−1 and 200 μmol·m−2·s−1 made no difference to the coloring rate; however, higher intensities resulted in an increase in the carotenoid content, which is responsible for the color in red sweet pepper fruit. Although temperatures of 15–25°C with light irradiation are considered to be appropriate for fruit coloring, the transpiration rate was found to increase in propotion to temperature rises, and the fruit wilted at 25°C. We also confirmed that fruit colored more than 50% by light irradiation continued getting colored in the dark at temperatures above 15°C. This combination of light irradiation and dark processing may potentially improve the ripening process efficiency and preserve the market value of fruit.