著者

Eizo NAKAMURA Katsura KOBAYASHI Ryoji TANAKA Tak KUNIHIRO Hiroshi KITAGAWA Christian POTISZIL Tsutomu OTA Chie SAKAGUCHI Masahiro YAMANAKA Dilan M. RATNAYAKE Havishk TRIPATHI Rahul KUMAR Maya-Liliana AVRAMESCU Hidehisa TSUCHIDA Yusuke YACHI Hitoshi MIURA Masanao ABE Ryota FUKAI Shizuho FURUYA Kentaro HATAKEDA Tasuku HAYASHI Yuya HITOMI Kazuya KUMAGAI Akiko MIYAZAKI Aiko NAKATO Masahiro NISHIMURA Tatsuaki OKADA Hiromichi SOEJIMA Seiji SUGITA Ayako SUZUKI Tomohiro USUI Toru YADA Daiki YAMAMOTO Kasumi YOGATA Miwa YOSHITAKE Masahiko ARAKAWA Atsushi FUJII Masahiko HAYAKAWA Naoyuki HIRATA Naru HIRATA Rie HONDA Chikatoshi HONDA Satoshi HOSODA Yu-ichi IIJIMA Hitoshi IKEDA Masateru ISHIGURO Yoshiaki ISHIHARA Takahiro IWATA Kosuke KAWAHARA Shota KIKUCHI Kohei KITAZATO Koji MATSUMOTO Moe MATSUOKA Tatsuhiro MICHIKAMI Yuya MIMASU Akira MIURA Tomokatsu MOROTA Satoru NAKAZAWA Noriyuki NAMIKI Hirotomo NODA Rina NOGUCHI Naoko OGAWA Kazunori OGAWA Chisato OKAMOTO Go ONO Masanobu OZAKI Takanao SAIKI Naoya SAKATANI Hirotaka SAWADA Hiroki SENSHU Yuri SHIMAKI Kei SHIRAI Yuto TAKEI Hiroshi TAKEUCHI Satoshi TANAKA Eri TATSUMI Fuyuto TERUI Ryudo TSUKIZAKI Koji WADA Manabu YAMADA Tetsuya YAMADA Yukio YAMAMOTO Hajime YANO Yasuhiro YOKOTA Keisuke YOSHIHARA Makoto YOSHIKAWA Kent YOSHIKAWA Masaki FUJIMOTO Sei-ichiro WATANABE Yuichi TSUDA

出版者

The Japan Academy

雑誌

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

巻号頁・発行日

vol.98, no.6, pp.227-282, 2022-06-10 (Released:2022-06-10)

参考文献数

245

被引用文献数

90

---

Presented here are the observations and interpretations from a comprehensive analysis of 16 representative particles returned from the C-type asteroid Ryugu by the Hayabusa2 mission. On average Ryugu particles consist of 50% phyllosilicate matrix, 41% porosity and 9% minor phases, including organic matter. The abundances of 70 elements from the particles are in close agreement with those of CI chondrites. Bulk Ryugu particles show higher δ18O, Δ17O, and ε54Cr values than CI chondrites. As such, Ryugu sampled the most primitive and least-thermally processed protosolar nebula reservoirs. Such a finding is consistent with multi-scale H-C-N isotopic compositions that are compatible with an origin for Ryugu organic matter within both the protosolar nebula and the interstellar medium. The analytical data obtained here, suggests that complex soluble organic matter formed during aqueous alteration on the Ryugu progenitor planetesimal (several 10’s of km), <2.6 Myr after CAI formation. Subsequently, the Ryugu progenitor planetesimal was fragmented and evolved into the current asteroid Ryugu through sublimation.

著者

Jun KIMURA Hauke HUSSMANN Shunichi KAMATA Koji MATSUMOTO Jürgen OBERST Gregor STEINBRÜGGE Alexander STARK Klaus GWINNER Shoko OSHIGAMI Noriyuki NAMIKI Kay LINGENAUBER Keigo ENYA Kiyoshi KURAMOTO Sho SASAKI

出版者

THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

雑誌

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN (ISSN:18840485)

巻号頁・発行日

vol.17, no.2, pp.234-243, 2019 (Released:2019-03-04)

参考文献数

50

被引用文献数

4

---

Laser altimetry is a powerful tool for addressing the major objectives of planetary physics and geodesy. Through measurements of distances between a spacecraft and the surface of the planetary bodies, it can be used to determine the global shape and radius: global, regional, and local topography: tidal deformation: and rotational states including physical librations. Laser altimeters have been applied in planetary explorations of the Moon, Mars, Mercury, and the asteroids Eros, and Itokawa. The JUpiter Icy Moons Explorer (JUICE), led by European Space Agency (ESA), has started development to explore the emergence of habitable worlds around gas giants. The Ganymede Laser Altimeter (GALA) will be the first laser altimeter for icy bodies, and will measure the shape and topography of the large icy moons of Jupiter, (globally for Ganymede, and using flyby ground-tracks for Europa and Callisto). Such information is crucial for understanding the formation of surface features and can tremendously improve our understanding of the icy tectonics. In addition, the GALA will infer the presence or absence of a subsurface ocean by measuring the tidal and rotational responses. Furthermore, it also improves the accuracy of gravity field measurements reflecting the interior structure, collaborating with the radio science experiment. In addition to range measurements, the signal strength and the waveform of the laser pulses reflected from the moon's surface contain information about surface reflectance at the laser wavelength and small scale roughness. Therefore we can infer the degrees of chemical and physical alterations, e.g., erosion, space weathering, compaction and deposition of exogenous materials, through GALA measurements without being affected by illumination conditions. JUICE spacecraft carries ten science payloads including GALA. They work closely together in a synergistic way with GALA being one of the key instruments for understanding the evolution of the icy satellites Ganymede, Europa, and Callisto.

著者

Jun KIMURA Hauke HUSSMANN Shunichi KAMATA Koji MATSUMOTO Jürgen OBERST Gregor STEINBRÜGGE Alexander STARK Klaus GWINNER Shoko OSHIGAMI Noriyuki NAMIKI Kay LINGENAUBER Keigo ENYA Kiyoshi KURAMOTO Sho SASAKI

出版者

THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES

雑誌

TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN (ISSN:18840485)

巻号頁・発行日

pp.17.234, (Released:2019-01-31)

参考文献数

50

被引用文献数

4

---

Laser altimetry is a powerful tool for addressing the major objectives of planetary physics and geodesy. Through measurements of distances between a spacecraft and the surface of the planetary bodies, it can be used to determine the global shape and radius: global, regional, and local topography: tidal deformation: and rotational states including physical librations. Laser altimeters have been applied in planetary explorations of the Moon, Mars, Mercury, and the asteroids Eros, and Itokawa. The JUpiter Icy Moons Explorer (JUICE), led by European Space Agency (ESA), has started development to explore the emergence of habitable worlds around gas giants. The Ganymede Laser Altimeter (GALA) will be the first laser altimeter for icy bodies, and will measure the shape and topography of the large icy moons of Jupiter, (globally for Ganymede, and using flyby ground-tracks for Europa and Callisto). Such information is crucial for understanding the formation of surface features and can tremendously improve our understanding of the icy tectonics. In addition, the GALA will infer the presence or absence of a subsurface ocean by measuring the tidal and rotational responses. Furthermore, it also improves the accuracy of gravity field measurements reflecting the interior structure, collaborating with the radio science experiment. In addition to range measurements, the signal strength and the waveform of the laser pulses reflected from the moon's surface contain information about surface reflectance at the laser wavelength and small scale roughness. Therefore we can infer the degrees of chemical and physical alterations, e.g., erosion, space weathering, compaction and deposition of exogenous materials, through GALA measurements without being affected by illumination conditions. JUICE spacecraft carries ten science payloads including GALA. They work closely together in a synergistic way with GALA being one of the key instruments for understanding the evolution of the icy satellites Ganymede, Europa, and Callisto.

著者

Koji MATSUMOTO Minoru FUJISAWA Hiroyuki SUGO Kunimi SUZUKI Kuniaki KOJIMA Masaki FUKASAWA Tomoe BEPPU

出版者

Japanese College of Surgeons

雑誌

日本外科系連合学会誌 (ISSN:03857883)

巻号頁・発行日

vol.27, no.6, pp.874-879, 2002-12-30 (Released:2009-08-13)

参考文献数

14

---

The surgical technique for idiopathic thrombocytopenic purpura (ITP) and hereditary spherocytosis (HS) has been changing from conventional open splenectomy (OS) to laparoscopic splenectomy (LS).In this study, we evaluated the usefulness of LS in comparison with OS. The subjects were 15 patients (14 with ITP and 1 with HS) who underwent surgery at our department. OS was performed in 5 patients (OS group), and LS was performed in 10 patients (LS group), of whom 2 underwent hand-assisted surgery. The perioperative parameters evaluated were : operative time, blood loss during operation, splenic weight, accessory spleens identified during operation, and conversion to open splenectomy.The postoperative parameters evaluated were : frequency of pain medication, duration until oral dietintake (days), interval of drainage (days), postoperative stay (days), residual accessory spleens, and complications. Conversion to open splenectomy was not observed in any patient. Blood loss was similar between the OS and LS groups.The operative time was significantly longer (p<0.05) in the LS group (mean, 232 ± 57 minutes) than in the OS group (mean, 155 ± 55 minutes), and the splenic weight was significantly lower (p<0.05) in the LS group (114 ± 86 g) than in the OS group (221 ± 76g). Accessory spleens were identified during operation in only 1 patient in the OS group. The frequency of pain medication was significantly lower (p<0.05) in the LS group (mean, 2.3 ± 1.3 vials) than in the OS group (7.4 ±1.1 vials), and the postoperative stay was significantly shorter (p<0.05) in the LS group (13.0 ± 5.4 days) than in the OS group (22.0 ± 7.1 days).Evaluation of long-term results 1 year or more after operation showed no change in 3 patients, but no significant differences were observed between LS and OS. LS may be more useful than OS because of better aesthetic results, less invasion, and shorter hospital stay despite some problems such as differences in surgical skills among surgeons and a longer operative time.