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Depositional condition of Paleoproterozoic Francevillian carbonate rocks revisited from rare earth element contents

Geoscience Frontiers 2024年第3期15卷 31-49页

作者： Satoshi Yoshida Karen Bakakas Mayika Yuki Ishihara Mathieu Moussavou hisashi asanuma Tomohiko Sato Takafumi Hirata Cédric Ligna Yusuke Sawaki Amboise Edou-Minko Department of Earth Science and Astronomy The University of Tokyo3-8-1 Komaba Meguro-kuTokyo 153-8902Japan Center for Northeast Asian Studies Tohoku University41 KawauchiAoba-kuSendai 980-8576Japan Department of Geology Universitédes Sciences et Techniques de MasukuBP:90190025 FrancevilleGabon Department of Earth and Planetary Science The University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-0033Japan Geochemical Research Center The University of Tokyo7-3-1HongoBunkyo-kuTokyo 113-0033Japan Graduate School of Human and Environmental Studies Kyoto UniversityYoshida-nihonmatsuSakyo-kuKyoto 606-8501Japan Center for Fundamental Education Okayama University of Science1-1Ridai-choKita-kuOkayama CityOkayama 700-0005Japan

The Paleoproterozoic Francevillian Group in the eastern Gabonese Republic has been recently attracting increasing attention because it includes distinctive macroscopic structures interpreted as eukaryotic ***,its depositional setting and associated redox conditions need to be clearly *** clarify these,petrological studies and rare earth element(REE)abundances of carbonate rocks of the Francevillian Group in the Lastoursville basin were determined with ICP-MS coupled with a laser ablation sampling *** microscopic observations indicate that dolostones in this basin underwent the complicated diagenetic history,including sparitization,decomposition of organic matter,reduction of ferromanganese oxides,silicification,and later *** dolostones of lower Francevillian B(FB)Formation show heterogeneous textures formed by alterations during *** the alterations,changes of REE abundances and degrees of positive Y anomalies appear to have *** indicates that REE signatures in carbonate rocks can vary during *** high Mn contents in the dolostones of upper FB Formation were derived from the reduction of ferromanganese oxides in *** signatures of REE abundance in dolostones can be explained by the mixing of seawater and ferromanganese oxide *** that sense,the dolostones inherited the trace element characteristics of precursor ferromanganese oxides even after the diagenesis.Y/Ho values of the most primary parts of each sample exceed 33,the newly determined threshold value for marine carbonate rocks based on our *** magnitude of the La anomaly values also falls within the range of that of Holocene reefal *** indicate that a precursor of the dolostone of the Francevillian Group was deposited in a marine *** addition,presence of Ce anomalies in the upper FB Formation suggests that the Paleoproterozoic ocean was oxidized to such an ex

关键词： Carbonate diagenesis Francevillian Group LA-ICP-MS Seawater composition Y/Ho fractionation

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Chronological constraints on the Paleoproterozoic Francevillian Group in Gabon

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Geoscience Frontiers 2017年第2期8卷 397-407页

作者： Yusuke Sawaki Mathieu Moussavou Tomohiko Sato Kazue Suzuki Cédric Ligna hisashi asanuma Shuhei Sakata Hideyuki Obayashi Takafumi Hirata Amboise Edou-Minkoinko Department of Earth and Planetary Sciences Tokyo Institute of Technology2-12-1 O-okayamaMeguro-kuTokyo 152-8551Japan University of Sdences and Technology in Masuku BP:90190025 FrancevilleGabon Earth-Life Science Institute(ELSI) Tokyo Institute of Technology2-12-1 O-okayamaMeguro-kuTokyo 152-8551Japan Department of Chemistry Gakushuin UniversityMejiro 1-5-1Toshima-kuTokyo 171-8588Japan Division of Earth and Planetary Sciences Graduate School of ScienceKyoto UniversityKitashirakawa Oiwake-choSakyo-kuKyoto 606-8502Japan Geochemistry Research Center The University of TokyoHongo 7-3-1Bunkyo-kuTokyo 113-0033Japan

The Francevillian Group in Gabonese Republic was recently established as a typical sedimentary sequence for the ***,its age is rather poorly constrained,mainly based on Rb-Sr and Nd-Sm *** study reports new zircon data obtained from Chaillu massif and N＇goutou complex,which constrain the protolith age of the basement orthogneisses and the igneous age of an intrusive granite,*** zircons from the orthogneisses are blue and exhibit oscillatory zoning in cathode-luminescence *** with lower common lead abundances tend to be distributed close to the concordia *** age clusters around 2860 Ma and 2910 Ma are found in zircons plotted on the concordia *** on the Th/U ratios of zircons,these ages correspond to the protolith ages of the orthogneisses,and the zircons are not metamorphic in *** and granites were collected from the N＇goutou complex that intrudes into the FA and FB units of the Francevillian *** granitoids exhibit chemical composition of A-type granite *** of zircons separated from the granite are non-luminous,and the remaining half exhibit obscure internal textures under cathode-luminescence *** zircon grains contain significant amounts of common lead;the lead isotopic variability is probably attributed to the mixing of two components in the *** zircon radiogenic ^（207）Pb/^（206）Pb ratio is 0.13707 ± *** to a ^（207）Pb/^（206）Pb age of 2191 ± 13 *** constrains the minimum depositional age of the FA and FB ***,the FB unit consists of manganese-rich carbonate rocks and organic carbon-rich black shales with macroscopic *** on our age constraints,these organisms appeared in the study area just after the last Paleoproterozoic Snowball Earth event,in concert with global scale oxidation event encompassing the Snowball Earth.

关键词： Gabon Francevillian Group Paleoproterozoic N'goutou complex Zircon MC-ICP-MS

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Influence of Livestock Farming on Vegetation in a Degraded Soil Area on the East Coast of Lake Victoria in Western Kenya: A Case Study of Jimo East Sub-Location in Nyando Sub-County

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Journal of Environmental Protection 2015年第8期6卷 824-836页

作者： Yuko Yamane Shuichi asanuma Kazuhiro Umenura International Cooperation Center for Agricultural Education (ICCAE) Nagoya University Nagoya Japan NARO Hokkaido Agricultural Research Center Sapporo Japan

In the study area located in Western Kenya near the Lake Victoria, severe soil erosion occurred and it thought to relate to vegetation degradation caused by overgrazing. The livestock density estimated by analyzing satellite image (1.39 TLU/ha for available grazing lands) was lower than that of measured for seven farmers’ grazing lands using GPSs (4.41 TLU/ha, 2011) with variation from 0.83 to 12.36 TLU/ha. Thus, it is clear that the grasslands used by farmers are limited compared with the area of estimated available land for grazing identified by analyzing the satellite image. According to growth-consumption rate model that was developed by the Nyangito et al. (2008) in southeastern Kenya, if livestock density reaches over 7 TLU/ha, pasture growth rate became lower than consumption rate. Grass biomasses of the grazing lands were kept low (less than 50 g/50 × 50 cm2) under high livestock density (three farmers out of seven were higher than 7 TLU/ha). In addition, rainfall pattern is very unstable and we observed stunted growth of grasses during dry spells. Therefore, we concluded that overgrazing. It means that inhibition of continuous re-growth of grasses due to high grazing pressure has been occurred even for small area and contributed to the soil erosion.

关键词： Luo Overgrazing Soil Erosion TLU Western Kenya

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Effect of Alteration of Glutathione Content on Cell Viability in α-Synuclein-Transfected SH-SY5Y Cells

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Advances in Parkinson's Disease 2017年第3期6卷 93-100页

作者： Ken-Ichi Tanaka Kanako Sonoda Masato asanuma Physiology and Pharmacology School of Health and Social Services Saitama Prefectural University Koshigaya Japan Department of Brain Science Okayama University Graduate School of Medicine Dentistry and Pharmaceutical Sciences Okayama Japan

It is well known that α-synuclein (αS) plays an important role in the pathogenesis of Parkinson’s disease (PD). Moreover, oxidative stress is also thought to be an important factor in PD due to induction of dopaminergic neuronal cell death by free radicals and enhancement of αS fibrillation by oxidized stress. In the present study, to clarify the role of glutathione (GSH), an intracellular antioxidant, on the molecular mechanism of αS-induced cell injury, we examined the effects of L-buthionine-SR-sulfoximine (BSO), a GSH synthase inhibitor, with or without N-acetyl-L-cysteine (NAC), a source of GSH, on αS-induced cell injury in human neuroblastoma SH-SY5Y cells. Treatment with BSO significantly reduced the cell viability of both empty-vector- and αS-transfected SH-SY5Y cells in a dose-dependent manner (p < 0.01), although the ratio of αS-induced reduction of cell viability in α-syn-transfected cells was much greater than that in empty-vector-transfected cells. Moreover, BSO significantly reduced the intracellular total GSH level in both types of transformant cells. However, NAC significantly prevented BSO-induced reduction of both cell viability and GSH level in the αS-transfected cells. These findings suggest that GSH plays an important role in αS-induced cell injury by reducing cell viability.

关键词： α-Synuclein L-Buthionine-SR-Sulfoximine N-Acetyl-L-Cysteine Glutathione SH-SY5Y Cells Parkinson’s Disease

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Gender difference in gastro-esophageal reflux diseases

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World Journal of Gastroenterology 2016年第5期22卷 1800-1810页

作者： kiyotaka asanuma katsunori iijima tooru shimosegawa Division of Gastroenterology Tohoku University Graduate School of MedicineMiyagi Prefecture 980-8574Japan

The incidence of esophageal adenocarcinoma(EAC) has risen sharply in western countries over the past 4 decades. This type of cancer is considered to follow a transitional process that goes from gastro-esophageal reflux disease(GERD) to Barrett's esophagus(BE,a metaplastic condition of the distal esophagus), a precursor lesion and ultimately adenocarcinoma. This spectrum of GERD is strongly predominant in males due to an unidentified mechanism. Several epidemiologic studies have des cribed that the prevalence of GERD, BE and EAC in women is closely related to reproductive status, which suggests a possible association with the estrogen level. Recently, we revealed in an in vivo study that the inactivation of mast cells by the anti-inflammatory function of estrogen may account for the gender difference in the GERD spectrum. Other studies have described the contribution of female steroid hormones to the gender difference in these diseases. Estrogen is reported to modulate the metabolism of fat, and obesity is a main risk factor of GERDs. Moreover, estrogen could confer esophageal epithelial resistance to causative refluxate. These functions of estrogen might explain the approximately 20-year delay in the incidence of BE and the subsequent development of EAC in women compared to men, and this effect may be responsible for the male predominance. However, some observational studies demonstrated that hormone replacement therapy exerts controversial effects in GERD patients. Nevertheless, the estrogen-related endocrine milieu may prevent disease progression toward carcinogenesis in GERD patients. The development of innovative alternatives to conventional acid suppressors may become possible by clarifying the mechanisms of estrogen.

关键词： gastro-esophageal reflux disease Barrett'sesophagus esophageal adenocarcinoma estrogen malepredominance

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Quantification of Annual Urban Growth of Dar es Salaam Tanzania from Landsat Time Series Data

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Advances in Remote Sensing 2017年第3期6卷 175-191页

作者： Kamara Emanuel Gombe Ichio asanuma Jong-Geol Park Graduate School of Informatics Tokyo University of Information Sciences Chiba Japan

The information on urban land cover distribution and its dynamics is useful for understanding urbanization and its impacts on the hydrological cycle, water management, surface energy balances, urban heat island, and biodiversity. This study utilizes machine learning, texture variables and spectral bands to quantify the urban growth annually. We used multi-temporal Landsat satellite image sets from 2007 to 2016 and Random Forest classification to map urban land-use in Dar es Salaam. We also applied Annual classification approach to detect the spatiotemporal patterns of urban areas. This approach improved classification accuracy and aided in understanding the urban land-use system dynamics operating in our study area. The results pointed out that, the total built-up areas have grown from 318 km2, 388.6 km2 and 634.7 km2 in 2007, 2012 and 2016 respectively. The built up areas growth rate is almost 8%, which makes Dar es Salaam be among the fastest growing cities in Africa. The results indicate that, combining spectral bands, texture variables (NDVI BCI, MNDWI) and annual classification map approach was sufficient to map the urban areas. The approach applied in this research provides a useful guide to the urban growth studies and may also serve as a tool for land management planners.

关键词： Random Forest Annual Classification Map Texture Analysis Dar es Salaam

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Spontaneous pneumothorax in a 17-year-old male patient with multiple exostoses:A case report and review of the literature

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World Journal of Orthopedics 2021年第11期12卷 945-953页

作者： Koichi Nakamura Kunihiro asanuma Akira Shimamoto Shinji Kaneda Keisuke Yoshida Yumi Matsuyama Tomohito Hagi Tomoki Nakamura Motoshi Takao Akihiro Sudo Department of Orthopedic Surgery Mie University Graduate School of MedicineTsu 514-8507Mie PrefectureJapan Department of Thoracic and Cardiovascular Surgery Mie University Graduate School of MedicineTsu 514-8507Mie PrefectureJapan

BACKGROUND Multiple exostoses generally develop in the first decade of *** most frequently arise from the distal femur,proximal tibia,fibula,and proximal *** exostoses are rare,contributing to 1%-2% of all exostoses in hereditary multiple exostoses(HME).They are usually asymptomatic,but a few cases have resulted in severe thoracic *** caused by costal exostoses is rare,with only 13 previously reported *** report a new case of pneumothorax caused by costal *** SUMMARY A 17-year-old male with HME underwent surgery for removal of exostoses around his right *** months following the operation,he felt chest pain when he was playing the trumpet;however,he did not stop playing for a *** was referred to our hospital with a chief complaint of chest *** computed tomography(CT)scan revealed right pneumothorax and multiple exostoses in his right *** CT scan also revealed visceral pleura thickness and damaged lung tissues facing the exostosis of the seventh *** diagnosed that exostosis of the seventh rib induced *** exostosis resection was performed by video-assisted thoracoscopic surgery(VATS)2 wk after the *** patient’s postoperative course was uneventful,and there was no recurrence of pneumothorax for 2 *** Costal exostoses causing thoracic injuries should be resected regardless of *** must be considered in cases with apparently benign and relatively small exostoses or HME.

关键词： Costal exostosis Pneumothorax Video-assisted thoracoscopic surgery Hereditary multiple exostoses Case report Treatment

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Chiral Electrodeposition by the Rotation in a Vertical Magnetic Field

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Journal of Iron and Steel Research International 2012年第S2期19卷 1158-1161页

作者： AOGAKI Ryoichi TAKAGI Satoshi MORIMOTO Ryoichi SUGIYAMA Atsushi MOGI Iwao asanuma Miki MIURA Makoto OSHIKIRI Yoshinobu YAMAUCHI Yusuke Polytechnic University Ryogoku Sumida-kuTokyo130-0026Japan National Institute for Materials Science(NIMS) Tsukuba Ibaraki305-0044Japan Saitama Prefectural Okubo Water Filtration Plant Saitama 338-0814Japan Graduate School of Advanced Science and Engineering Waseda University Institute for Materials Research Tohoku University Yokohama Harbour Polytechnic College Polytechnic College Akita Yamagata College of Industry and Technology National Institute for Materials Science(NIMS)

The roles of the rotations in the process of chirality appearance in magnetoelectrodeposition were theoretically *** in a vertical magnetic field induces a macroscopic fluid rotation called vertical MHD flow(VMHDF) over the electrode *** the rotation,minute numerous micro-vortexes called micro-MHD flow(MMHDF) arise from 2D and 3D nucleation,which interact with the mass flux of metallic ion,yielding chiral deposits with the characteristic features called micro- and nano-mystery ***,numerous vortexes always keep chiral symmetry,forming four types of vortexes,i.e.,with the combination of upward or downward and clockwise or ***,ionic vacancy acting as an atomic scale lubricant is created in electrodeposition,which gives a restriction to the vortexes;the bottom of an upward vortex covered with ionic vacancies becomes a free surface without friction,whereas the bottom of a downward vortex exposed without ionic vacancies remains rigid with *** rotation of VMHDF donates a precession to the upward vortexes to rotate in the same direction,which finally yield a chiral *** similar effect to that of VMHDF can be expected for the system rotation(SR),where an electrolytic cell rotates in a vertical magnetic *** this case,the SR gives the reverse rotation to the upward vortexes,so that a deposit with reverse chirality is obtained.

关键词： chirality chiral electrodeposition magnetoelectrodeposition rotation magnetic field ionic vacancy

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Effect of Various Intensities of Drought Stress on δ<sup>13</sup>C Variation among Plant Organs in Rice: Comparison of Two Cultivars

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American Journal of Plant Sciences 2014年第11期5卷 1686-1693页

作者： Mana Kano-Nakata Jiro Tatsumi Yoshiaki Inukai Shuichi asanuma Akira Yamauchi Center for Bioresource Field Science Kyoto Institute of Technology Kyoto Japan Graduate School of Bioagricultural Sciences Nagoya University Aichi Japan Graduate School of Bioagricultural Sciences Nagoya University Aichi Japan International Corporation Center for Agricultural Education (ICCAE) Nagoya University Aichi Japan International Corporation Center for Agricultural Education (ICCAE) Nagoya University Aichi Japan

The δ13C value is widely used to assess the effects of drought on water status in plants. However, there is little information regarding the δ13C signature in different organs of rice. We conducted a field study to examine whether the δ13C among different plant parts would be affected by the intensities of drought, and to evaluate genotypic variation in δ13C fluctuation among plant parts affected by drought intensities. Two cultivars, “Nipponbare” (Oryzasativa ssp. japonica) and “Kasalath” (O. sativa ssp. indica), were grown in the field with a line-source sprinkler system. The δ13C values of panicles, flag leaves, straws, culms, and roots were measured from plant samples. The δ13C value increased as drought stress increased, especially in the panicles and roots. “Nipponbare” showed higher values of δ13C than “Kasalath” under the well-watered and mild drought stress conditions, but there was no significant difference between the genotypes in the δ13C value under the severe drought stress condition. The variation in δ13C value among different plant parts was also increased with increasing drought stress. In contrast, these variations were small under well-watered conditions. Furthermore, there was much greater variation in the δ13C value among different plant parts in “Kasalath” than in “Nipponbare” when the plants were grown under drought stress conditions. A significant negative relationship was observed between the δ13C value of panicles and shoot dry matter production, suggesting that the δ13C value of panicles may be the best indicator of plant water status in rice.

关键词： δ13C Drought Plant Parts Rice

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Island Activities Detected by VIIRS and Validation with AIS

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Advances in Remote Sensing 2018年第3期7卷 171-182页

作者： Ichio asanuma Daisuke Hasegawa Takashi Yamaguchi Jong Geol Park Kenneth James Mackin Department of Informatics Tokyo University of Information Sciences Chiba Japan

A possibility to monitor the reclamation activities by remote sensing was discussed. The lights observed in the night time by Day Night Band (DNB) of Visible Infrared Imaging Radiometer Suite (VIIRS), ocean color observed in the day time by visible bands of VIIRS were the tools to monitor the surface activities, and the Automated Information System (AIS) was used to verify the types and number of vessels associated with the reclamation activities. The lights as the radiance from the surface were monitored by the object based analysis, where the object was defined as a radius of 5 km from the center of the Mischief Reef in the South China Sea (SCS). The time history of surface lights exhibited the increase of the radiance from January to May 2015 and the radiance was kept in the certain level to December 2016 with some variations. The ocean color, chlorophyll-a concentration as a proxy of sediments, showed an increase from February to June 2015 and returned to a low concentration in August 2015. According to the historical data of AIS, the number of dredgers has increased from February to August 2015 and the maximum number of dredgers was recorded in June 2015. The timing of increase of lights from surface, increase of chlorophyll-a concentration, and increase of number of vessels are consistent.

关键词： Dredging Reclamation VIIRS DNB Chlorophyll-a AIS

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