Faculty Profiles - MINAMI, Masayo

Papers - MINAMI, Masayo

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The Penjween gabbro, northeastern Iraq, revealing a forearc hyperextension regime with a slow spreading ridge center in the Late Cretaceous

Azizi, H; Yara, I; Ali, SA; Mohammad, YO; Asahara, Y; Minami, M; Shin, KC; Anma, R; Whattam, SA

GEOCHEMISTRY Vol. 85 ( 1 ) 2025.4

Publisher：Geochemistry

In the Zagros suture zone of western Iran, mafic and ultramafic rocks, along with deep marine sediments, are exposed and known as the Zagros ophiolites. Among these, the Penjween ophiolite in northeastern Iraq is notable and it is predominantly composed of gabbroic and mantle peridotite (tectonite), and also features minor felsic rocks like plagiogranites and mafic members such as pillow lavas and sheeted dikes. The Penjween gabbro which is the subject of this research were compressed between mantle peridotite to the east and Jurassic-Cretaceous cherts and Bistun limestone to the west. The chemical composition of the gabbroic rocks indicates low contents of alkaline elements, with higher FeOt and MgO contents and low K contents and tholeiitic affinity. The basaltic and fine-grained gabbro have slightly higher alkaline element contents and LREE/HREE ratios than the gabbroic rocks, with slightly higher 87Sr/86Sr ratios (0.7038–0.7074) and lower 143Nd/144Nd ratios (0.51294–0.51301) than the gabbroic rocks with 87Sr/86Sr (0.7036–0.7054) 143Nd/144Nd (0.51281–0.51366) ratios. The basaltic rocks have a close affinity with the MORB composition, while the gabbroic rocks have Ce negative anomalies consistent with sources of hydrated depleted mantle melting. Therefore, given the 107 Ma age of the arc magmatic rocks in northwest Iran and the 98–93 Ma age of the plagiogranite in the Penjween area, the Penjween gabbros are 15–10 Ma younger than the magmatic activity in the northern Sanandaj-Sirjan zone (N-SaSZ) in western Iran. The Neotethys subduction probably began beneath the N-SaSZ at approximately 110 Ma, with nascent oceanic crust near the trench zone. Subsequently, the nascent plate spreading ridge slowly developed, resulting in the formation of the Penjween ophiolite in a supra-subduction system. The extensional regime in the forearc basin allowed for the exhumation of a large volume of mantle peridotite in the oceanic crust as a core complex. This process is known as forearc hyperextension, which has occurred in supra-subduction zones.

DOI： 10.1016/j.chemer.2024.126241

Web of Science

Scopus

Redox control in arsenic accumulation with organic matter derived from a varved lacustrine deposit in the Jurassic accretionary complexes Reviewed

Masuki Y., Katsuta N., Naito S., Murakami T., Umemura A., Fujita N., Matsubara A., Minami M., Niwa M., Yoshida H., Kojima S.

Journal of Hazardous Materials Vol. 485 page： 136843 2025.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Hazardous Materials

Oxidation states and distribution of arsenic (As) in annually laminated (varved) lacustrine deposits were analyzed with a seasonal resolution. This deposit was formed in the mid-Holocene landslide-dammed paleolake in the upper reaches of the Ane River, central Japan and the paleolake watershed consists of the Jurassic accretionary complexes (Mino-Tamba belt) including sedimentary and igneous rocks. In the outcrop, centimeter-to-decimeter-scale silty clay layers alternating with laminated layers are well developed. Bulk concentrations of As in the two layers are 77 ± 27 μg/g on average and mostly occurred in the sulfide fraction (59 % ± 9 %). In the laminated layers, millimeter-scale organic matter (OM)-rich and siderite-rich layers were repeated, indicating deposition during the spring and autumn mixings and the summer stratification, respectively. The OM-rich layers distinctively contain As-rich layers concentrated at the margins of the siderite layers, while they have numerous As-rich hotspots coexisting with S and amorphous OM. Synchrotron-based micro-X-ray absorption near edge structure analysis demonstrated that the As-rich layers contain FeAs–IS, AsIIS, and AsIII2S3 at roughly the same levels, whereas FeAs–IS is dominant for the As in hotspots. Based on the results, it is suggested that As accumulation in the varved deposit has been controlled by seasonal changes in OM supply and fluctuation in redox potential with post-depositional degradation of OM.

DOI： 10.1016/j.jhazmat.2024.136843

Scopus

PubMed

Strontium-isotope mapping of the Kyushu islands, southwestern Japan, using stream sediments Open Access

Ohta Atsuyuki, Goto Akiko S., Wakaki Shigeyuki, Minami Masayo

GEOCHEMICAL JOURNAL Vol. 59 ( 1 ) page： 9 - 25 2025

Language：English Publisher：GEOCHEMICAL SOCIETY OF JAPAN

A geochemical mapping study was conducted to investigate the spatial distribution of 87Sr/86Sr ratios in Kyushu. The study aimed to understand the factors controlling the geochemical distribution of Sr isotopes in stream sediments more completely. Using a thermal ionization mass spectrometer, we analyzed the 87Sr/86Sr of 307 stream sediments collected for geochemical mapping in Japan. The results showed that systematic variations in 87Sr/86Sr ratios correlate with surface geology. Stream sediments derived from mafic volcanic and pyroclastic rocks displayed low 87Sr/86Sr ratios (0.704–0.708), whereas those derived from felsic volcanic, granitic, and metamorphic rocks showed intermediate Sr isotope ratios (0.705–0.711). In the northwestern and southeastern areas underlain with accretionary complex and non-accretionary sedimentary rock, high 87Sr/86Sr ratios (0.705–0.721) were observed in the stream sediments. Based on the 87Sr/86Sr data of stream sediments derived from these rock types, we found a predominant supply of clastic materials originating from the Asian continent to the Paleogene back-arc basin in northwest Kyushu and the Paleogene subduction zone in southwest Kyushu. This suggests that the Sr isotope map is useful for the provenance analysis of clastic particles in sedimentary rocks. Furthermore, we present a map of the 87Sr/86Sr ratio in the exchangeable fraction of stream sediments. This fraction, which dissolves easily in water and is accessible for plants, is important for provenance studies of agricultural products. The 87Sr/86Sr ratio in the exchangeable fraction was predominantly affected by the presence of plagioclase in stream sediments and exhibits a positive correlation with that in the bulk fraction.

DOI： 10.2343/geochemj.GJ24027

The Penjween gabbro, northeastern Iraq, revealing a forearc hyperextension regime with a slow spreading ridge center in the Late Cretaceous Reviewed International coauthorship

Hossein Azizi, Irfan Yara, Sarmad Asi Ali, Yousif O. Mohammad, Yoshihiro Asahara, Masayo Minami, Ki-Choel Shin, Ryo Anma, Scott A. Whattam

Geochemistry page： 126241 2024.12

Ultrapotassic rocks in the Saray Peninsula, Northwest Iran: An example of carbonate peridotite melts in a post-collision system in the late Miocene

Azizi, H; Nouri, F; Asahara, Y; Minami, M; Tsuboi, M; Takahashi, HA; Whattam, SA

LITHOS Vol. 488 2024.12

Publisher：Lithos

Late Miocene ultrapotassic rocks are widely exposed in the Saray Peninsula of northwestern Iran. These rocks are mainly classified as tephrite-tephritic phonolite with some trachyte and lamprophyre dikes with porphyritic textures. Ca-rich pyroxene and leucite are the main phenocrysts. Olivine and phlogopite with some sodic amphiboles occur locally as phenocrysts. Chemically, the rocks are characterized by low contents of SiO2 (45.4–47.3 wt%), with high contents of K2O (3.4–6.6 wt%), K2O/Na2O (1.2–5.7), MgO (5.6–9.1 wt%), CaO (10.3–12.7 wt%) and Sr (826–2020 ppm) with low P2O5/Al2O3 (0.08–0.14). Chondrite normalized REE and primitive mantle-normalized patterns indicate the involvement of a LREE (La, Ce) and LILE (Cs, Ba, Pb) enriched mantle, and weak negative Ti-Nb-Ta anomalies are observed. Isotopically, the rocks show high 87Sr/86Sr ratios (0.7071–0.7084) and low εNd(t) values (–3.8 to –1.8). Their δ13C values show a variation from –13.4 ‰ to –6.5 ‰, confirming some organic carbon recycling in the subduction zone, and the absence of Ce/Ce* and Eu/Eu* negative anomalies confirm the redox system melting. The Sr[sbnd]Nd isotopic values, higher contents of incompatible elements, and lower δ13C values suggest a continental crustal material involvement for the sources of these rocks. The presence of calcite in the matrix, the inclusion of melt droplets with some calcite, and the carbonation of leucite and pyroxene grains confirm the high CO2 content during magmatic evolution and/or the late stages of reaction of CO2-fluid rocks with earlier minerals. Due to the situation of the Saray ultrapotassic rocks near the junction of the Van microplate and the NW Iran block, dragging of the Van microplate beneath NW Iran is likely to have transported some carbonate rocks and biogenetic organic carbon into the mantle and converted the primitive mantle to carbonate peridotite. A very low rate of partial melting at a pressure of less than 3 GPa around the garnet-spinel stable zone produced ultrapotassic melts. The correlation with some neighboring ultrapotassic rocks shows that this process is a dominant factor to generate the kamafugite and/or interval of kamafugite-Roman type ultrapotassic series in a collision system, without considering the role of mantle phlogopite present in the deep metasomatized mantle. This work shows why most of the ultrapotassic rocks in Iran have developed near the suture zone after the closure of Neotethys.

DOI： 10.1016/j.lithos.2024.107788

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Scopus

FOSSILIZATION OF WELL-PRESERVED DEEP-SEA LANTERNFISH: A CASE STUDY FROM THE MIOCENE MOROZAKI GROUP, CHITA PENINSULA, SOUTHWEST JAPAN Reviewed

HARUKA KATADA, HIDEKAZU YOSHIDA, TATSUO OJI, YOSHIHIRO ASAHARA, MASAYO MINAMI, YUI KOUKETSU

PALAIOS 2024.11

Continental crust variance between post-collisional compressional and extensional domains controlled magmatic activity at Damavand volcano, Northern Iran

Azizi, H; Nouri, F; Asahara, Y; Minami, M; Whattam, SA

INTERNATIONAL GEOLOGY REVIEW 2024.7

Publisher：International Geology Review

The Quaternary Damavand stratovolcano, with an elevation of 5670 m, is the highest mountain in Iran and is the subject of this study. The main rocks are trachyandesite and trachybasalt, and Sr-Nd isotope ratios of whole rock samples show small variations in ɛSr (+3.2 to + 6.4) and ɛNd (−1 to + 1). Overall, rock chemistry and Sr-Nd isotope ratios support a metasomatic asthenospheric mantle with minor pelagic sediments from the oceanic subducted slab and/or carbonatite melts from the deep mantle as sources. Collision of the Arabian and Eurasian plates compressed the Iranian plateau between them, resulting in compressional and extensional domains in different regions. As a result of continuous pressure from the Arabian plate, thrusting and folding in compressional domains increased crustal thickness while thinning occurred in extensional areas. These processes cause thermal gradient perturbations at the boundaries between the two, leading to the melting of the mantle and/or lower crustal mafic rocks and production of alkaline rocks. Damavand volcano is located at the junction of compressional and extensional regimes, and its activity has been influenced by the variation of crustal thickness along the Alborz Mountain in the southern Caspian Sea. Therefore, the variation of crustal thickness can be suggested as a main mechanism for the generation of magmatic activity along the entire Iranian plateau in a post-collision system.

DOI： 10.1080/00206814.2024.2370493

Web of Science

Scopus

軽石流に埋められた浅間火山北麓の埋没林：樹種および14C年代 Reviewed

佐藤興平・南　雅代・児嶋美穂・山岸松平・黒岩俊明・安部　久・洪　完

群馬県立自然史博物館研究報告 Vol. 28 page： 145 - 150 2024.3

浅間火山北麓に分布する湖成層と火山泥流堆積物：埋没木片の樹種と14C年代の予察的検討 Reviewed International coauthorship

佐藤興平・南　雅代・児嶋美穂・山岸松平・安部　久・洪　完

群馬県立自然史博物館研究報告 Vol. 28 page： 151 - 160 2024.3

フォッサマグナ地域の新第三紀～第四紀火成岩類のSr同位体比：時空分布の特徴 Reviewed International coauthorship

佐藤興平・南　雅代・若木重行

群馬県立自然史博物館研究報告 Vol. 28 page： 129 - 144 2024.3

O-Hf isotope ratios of Alvand S-type granite, western Iran, reveal crustal melting in an extensional regime

Azizi, H; Daneshvar, N; Rafat, G; Asahara, Y; Horie, K; Takehara, M; Kon, Y; Minami, M; Anma, R

LITHOS Vol. 464 2024.1

Publisher：Lithos

There are a few intrusive bodies in the central Sanandaj-Sirjan Zone (C-SaSZ), which is parallel to the Zagros suture zone, in western Iran. The Alvand batholith in the Hamedan area is one of these bodies and consists of rock types with large variation, in particular, two-mica garnet-bearing granite with an S-type signature. Zircon U[sbnd]Pb dating gives crystallization ages of 170–163 Ma for the S-type granite. The 176Hf/177Hf ratios in the zircon grains vary from 0.282001 to 0.282780 (rim), with low 176Lu/177Hf ratios (0.002 to 0.018). The εHf(t) values (rim) are clustered into two main groups: a negative εHf(t) group (−6.9 to 0.0, n = 39), with some highly negative εHf(t) values (−25.8 to −21.9, n = 3), and slightly positive εHf(t) values (+0.3 to +2.9, n = 14) of inherited grains. The δ18O values for the zircon grains are positive and range from +10.4‰ to +11.8‰. The high δ18O (positive) and mostly negative εHf(t) values are more consistent with continental crustal sources for these rocks, and the Hf model ages (TDM2) show a wide range from 2.7 to 0.8 Ga, suggesting the heterogeneity of the crustal components. The long incubation time (2089 to 544 Ma) indicates a long history of crustal residence and crustal reworking. The incubation age of the zircon grains, >300 Ma, confirms the recycling of crustal material by partial melting. The simultaneous occurrence of S-type granites with mafic bodies, such as gabbro and diorite members with tholeiitic signatures, suggests that the injection of mafic magma increased the geothermal gradient from the bottom and sides along the major faults, which was the trajectory for the injection of hot mafic melts to shallow depths. These processes abnormally increased the geothermal gradients locally, and the partial melting of crustal and supracrustal materials produced S-type granites and migmatization among the hot blade-shaped mafic bodies. Therefore, the partial melting of crustal material in an extensional tectonic regime and/or in a thin continental crust occurred in a continental rift and/or in the Neo-Tethys passive margin. The present work concludes that the passive margin can be suggested as the tectonic setting for the generation of S-type granites, without the collisional regime that has been widely considered for the sources of this type of granite in the world.

DOI： 10.1016/j.lithos.2023.107437

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Scopus

Chemical and Sr isotopic compositions of beryl crystals in the Ebrahim-Attar pegmatite, NW Iran, indicate melting of the upper continental crustal source

Narges Daneshvar, Masayo Minami, Hossein Azizi, Yoshihiro Asahara, Motohiro Tsuboi, Yosif Mohammad

Abstracts of Annual Meeting of the Geochemical Society of Japan Vol. 71 ( 0 ) page： 233 2024

Prediction of magma crystallization temperature using the high field strength elements and correlation with Zr saturation index

Narges Daneshvar, Hossein Azizi, Motohiro Tsuboi, Masayo Minami, Yoshihiro Asahara

Abstracts of Annual Meeting of the Geochemical Society of Japan Vol. 71 ( 0 ) page： 240 2024

Verification Method of Direct Air Capture by Cementitious Material Using Carbon Isotopes

Wang Zhenzhen, Aili Abudushalamu, Minami Masayo, Maruyama Ippei

Journal of Advanced Concrete Technology Vol. 21 ( 11 ) page： 934 - 940 2023.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Japan Concrete Institute

Capturing atmospheric CO2 into cement-based materials is a way to set off the CO2 emissions of concrete production. This study proposes an experimental method to track the origin of cement paste that fixes CO2 directly from the air under natural conditions. By exposing powders of well-hydrated cement paste to air, carbonated cement paste powders are obtained with different carbonation degrees. The inorganic carbon of these carbonated samples is extracted by dissolution in phosphoric acid, and the isotopic characteristics related to 13C and 14C are measured. The experimental results show that the 14C value of carbonated cement paste can be used as an indicator for tracing the origin of carbon.

DOI： 10.3151/jact.21.934

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Scopus

CiNii Research

Geochemistry and 14C dating of guano deposits in the Karaftu Cave, Kurdistan, Iran: implication for paleoenvironment Reviewed International coauthorship

Amin-Rasouli, H; Minami, M; Armstrong-Altrin, JS; Jou, NH; Moradi, M

ENVIRONMENTAL MONITORING AND ASSESSMENT Vol. 195 ( 10 ) page： 1144 2023.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Environmental Monitoring and Assessment

Karaftu Cave in the northwest of Divandareh includes four floors plus an underground area. The bat hall and its underground area are covered with guano deposits. 14C dating indicates the onset of guano deposition is about 14,260±50 BP years, and its average accumulation rate is about 4.1 mm/yr for depths of 360 to 205 cm. Bacterial and fungal metabolisms decay guano, release acids, and disperse large amounts of microorganisms inside the cave. Interactions between acids and guano caused leaching, dissolution, change in the distribution, and abundance of elements, which leads to the formation of secondary minerals in guano. These variations in minerals and elements also depend on the local climatic conditions. Distribution of elements in the Ce/Ce* versus Pr/Pr* diagram and the correlation coefficient between Ce and Mn display three different paleoclimate conditions (dry, wet, and dry) during the accumulation of the guano. Also, dolomite, phosphate, and iron oxide minerals have been formed during the passage of water through bedrock beneath the guano. This water is unsuitable for drinking and harmful to the organisms in the region. Effect of these acids on the substrate also leads to the collapse of the cave floor, generation of a new underground, fall in the groundwater level, change in the groundwater drainage system, drying of springs around the cave, loss of green cover, and a negative impact on the ecosystem in the region. To keep the cave environment clean and remove these problems, it is better to harvest guano and use it as fertilizer.

DOI： 10.1007/s10661-023-11624-9

Web of Science

Scopus

PubMed

RADIOCARBON CONCENTRATION IN SUB-ANNUAL TREE RINGS FROM POLAND AROUND 660 BCE Reviewed International coauthorship

Rakowski, AZ; Pawlyta, J; Miyahara, H; Krapiec, M; Molnár, M; Wiktorowski, D; Minami, M

RADIOCARBON 2023.9

Publishing type：Research paper (scientific journal) Publisher：Radiocarbon

The article presents results of measurements of radiocarbon (14C) concentration in sub-annual dendrochronologically dated tree rings of English oak (Quercus robur L.) from Grabie village near Kraków (southern Poland). Samples of early wood (EW) and late wood (LW) spanning the years 664-658 BCE. α-cellulose was extracted from each sample and their radiocarbon content was measured at the ATOMKI laboratory in Debrecen, Hungary. The EW and LW data confirm a prolonged increase in "14C values around 665-663 as was observed by Park et al. (2017), Rakowski et al. (2019), or Sakurai et al. (2020). In addition, we found that this event may consist of two relatively small events, as was proposed by Sakurai et al. (2020). Based on obtained in this and previous study data we estimate that the occurrence of the two events were between 665 and 664 BCE (Rakowski et al. 2019), and in late spring of 663 BCE (May-June, before beginning of LW formation).

DOI： 10.1017/RDC.2023.79

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Scopus

The Generation of Eocene Mafic Dike Swarms During the Exhumation of a Core Complex, Biarjmand Area, NE Iran Reviewed International coauthorship

Azizi, H; Daneshvar, N; Asahara, Y; Minami, M; Anma, R

JOURNAL OF PETROLOGY Vol. 64 ( 6 ) page： 1 - 18 2023.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Petrology

Several swarms of parallel E-W dikes cuts late Neoproterozoic- to early Paleozoic (540 Ma) basement in the Biarjmand area, NE Iran. The microgabbroic to doleritic dike are several hundred meters long and 0.5 to 3 meters wide. U-Pb dating of their zircon grains yields a crystallization age of 46.0 ± 7.1 Ma for the dike swarms. The dikes have SiO2 contents of 46.0-49.3 wt%, and Fe2O3 contents of 9.80-14.8 wt% with variable MgO (4.92-9.16 wt%), TiO2 (1.47-2.65 wt%), and K2O contents (0.33-1.13 wt%). The dikes have low contents of high field strength elements (HFSEs), and have some similarities to transitional mid-ocean ridge basalts (T-MORB) based on their chemical composition. Positive values of +5.2 to +6.0 for the dike samples imply that the basaltic magma was generated from depleted lithospheric mantle. After the closure of the Sabzevar ocean and obduction of the large mantle peridotite body over the continental crust in the late Cretaceous-Paleocene, the gravitational instability in the central Iran/Eurasia plate collision zone triggered exhumation of old basement coeval with injection of the mafic magma. During exhumation, mylonitic deformation with brittle-ductile structures affected the basement metagranite and the host rocks. The metagranite and dike swarms cut the Cretaceous Sabzevar ophiolite, and the disparting of ophiolite members probably occurred during basement exhumation in the Cenozoic. The similar ages of the mafic dike swarms and other Eocene magmatic rocks of the Urumiah (Urmia) Dokhtar magmatic arc (UDMA), western Iran, is consistent with a rapid extensional regime over the Sabzevar suture zone on an earlier collision zone in NE Iran. This process provided a suitable setting for the exhumation of the old basement, the emplacement of the parallel dike swarm, and the development of shallow basins in this area.

DOI： 10.1093/petrology/egad039

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Molecular Phylogeny and New Haplotypes of Extinct Asian Black Bear Populations in Kyushu Island, Japan

ITOH Tetsuji, SATO Yoshikazu, ISHIGURO Naotaka, SHIMIZU Minoru, KURIHARA Nozomi, MINAMI Masayo, YAMAZAKI Koji

Japanese Journal of Zoo and Wildlife Medicine Vol. 28 ( 1 ) page： 35 - 44 2023.4

Language：English Publishing type：Research paper (scientific journal) Publisher：Japanese Society of Zoo and Wildlife Medicine

Asian black bears (Ursus thibetanus) in Japan are clustered into 3 lineages (eastern, western, and southern clusters) based on mitochondrial DNA (mtDNA) haplotypes of an approximately 700 bp sequence in the D-loop region of mtDNA. In 2012 the Ministry of the Environment of Japan announced the Asian black bear population in Kyushu, the southwestern island of the Japanese archipelago, as locally extinct, because the last reliable record of the Asian black bear in Kyushu was in 1941. The number of samples and genetic analysis results pertaining to the Asian black bear population in Kyushu are very few. Therefore, the molecular phylogenetic characteristics of Asian black bears in Kyushu remain a missing link in understanding the trajectory of Asian black bear populations from the Asian mainland to Japan. In this study, we investigated the mtDNA haplotypes of Asian black bears in Kyushu using four old bone samples, which we found at various locations and dates. We succeeded in detecting two new haplotypes and a haplotype of the western cluster. The two new haplotypes also belonged to the western cluster. These results suggest a continuous distribution of Asian black bears between western Chugoku and Kyushu, and indicate that genetic variation occurred after habitat fragmentation. These results provide data to support the considerations of previous studies on the migration of Asian black bears from the Asian continent to the Japanese archipelago.

DOI： 10.5686/jjzwm.28.35

CiNii Research

群馬・長野県境域に分布する新第三紀～第四紀火成岩類の Sr同位体比：時空分布の予察的検討 Reviewed

佐藤興平・南雅代・若木重行・中野俊

群馬県立自然史博物館研究報告 Vol. 27 page： 83 - 94 2023.3

名古屋港と清水港で採集された完新世炭酸塩コンクリーションの14C年代測定

南雅代

第23回AMSシンポシウム報告集 Vol. - page： 56 - 59 2023

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Papers - MINAMI, Masayo