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Journal Articles

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.

Science, 364(6437), p.272 - 275, 2019/04

 Times Cited Count:86 Percentile:0.14(Multidisciplinary Sciences)

The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

Journal Articles

Reversible structural changes and high-rate capability of Li$$_{3}$$PO$$_{4}$$-modified Li$$_{2}$$RuO$$_{3}$$ for lithium-rich layered rocksalt oxide cathodes

Taminato, So*; Hirayama, Masaaki*; Suzuki, Kota*; Kim, K.-S.*; Tamura, Kazuhisa; Kanno, Ryoji*

Journal of Physical Chemistry C, 122(29), p.16607 - 16612, 2018/07

 Times Cited Count:5 Percentile:55.06(Chemistry, Physical)

Lithium-rich layered rocksalt oxides are promising cathode materials for lithium-ion batteries. We investigate the effects of surface modification by amorphous Li$$_{3}$$PO$$_{4}$$ on the structures and electrochemical reactions in the surface region of an epitaxial Li$$_{2}$$RuO$$_{3}$$(010) film electrode. Structural characterization using SXRD, HAXPES, and NR shows that surface modification by Li$$_{3}$$PO$$_{4}$$ resulted in the partial substitution of P for Li in the surface region of Li$$_{2}$$RuO$$_{3}$$. The modified (010) surface exhibits better rate capability at 20 C compared to the unmodified surface. ${it In situ}$ surface XRD confirmed that highly reversible structural changes occurred at the modified surface during lithium (de)intercalation. These results demonstrate that this surface modification stabilizes the crystal structure in the surface region, and it can improve the rate capability of lithium-rich layered rocksalt oxide cathodes.

Journal Articles

Report on a Workshop of the 23th Young Researchers Association, a Fukushima Daiichi Nuclear Power Plant tour and the 10th Conference of Students Association of the Japan Health Physics Society

Matsuyama, Tsugufumi*; Suzuki, Tatsuhiko*; Migita, Yukie; Ishii, Kota*; Ueno, Satoshi*

Hoken Butsuri, 52(3), p.226 - 230, 2017/09

no abstracts in English

Journal Articles

Potential for microbial H$$_{2}$$ and metal transformations associated with novel bacteria and archaea in deep terrestrial subsurface sediments

Hernsdorf, A. W.*; Amano, Yuki; Miyakawa, Kazuya; Ise, Kotaro; Suzuki, Yohei*; Anantharaman, K.*; Probst, A. J.*; Burstein, David*; Thomas, B. C.*; Banfield, J. F.*

ISME Journal, 11, p.1915 - 1929, 2017/03

AA2016-0002.pdf:2.21MB

 Times Cited Count:43 Percentile:2.77(Ecology)

To evaluate the potential for interactions between microbial communities and disposal systems, we explored the structure and metabolic function of a sediment-hosted subsurface ecosystem associated with Horonobe Underground Research Center, Hokkaido, Japan. Overall, the ecosystem is enriched in organisms from diverse lineages and many are from phyla that lack isolated representatives. The majority of organisms can metabolize H$$_{2}$$, often via oxidative [NiFe] hydrogenases or electron-bifurcating [FeFe] hydrogenases that enable ferredoxin-based pathways, including the ion motive Rnf complex. Many organisms implicated in H$$_{2}$$ metabolism are also predicted to catalyze carbon, nitrogen, iron, and sulfur transformations. Notably, iron-based metabolism was predicted in a bacterial lineage where this function has not been predicted previously and in an ANME-2d archaeaon that is implicated in methane oxidation. We infer an ecological model that links microorganisms to sediment-derived resources and predict potential impacts of microbial activity on H$$_{2}$$ accumulation and radionuclide migration.

Journal Articles

Study on the deterioration mechanism of layered rock-salt electrodes using epitaxial thin films; Li(Ni, Co, Mn)O$$_{2}$$ and their Zr-O surface modified electrodes

Abe, Machiko*; Iba, Hideki*; Suzuki, Kota*; Minamishima, Hiroaki*; Hirayama, Masaaki*; Tamura, Kazuhisa; Mizuki, Junichiro*; Saito, Tomohiro*; Ikuhara, Yuichi*; Kanno, Ryoji*

Journal of Power Sources, 345, p.108 - 119, 2017/03

 Times Cited Count:8 Percentile:50.02(Chemistry, Physical)

The surface structure of the Li(Ni, Co, Mn)O$$_{2}$$ electrode was studied during charge/discharge process using electrochemical methods and X-ray/Neutron scattering techniques. It was found that during charge/discharge process the coverage of spinel structure increased. The spinel structure has low electrochemical activity and is not involved in Li insertion/extraction. After the surface modification, it was found that the coverage of the spinel structure did not increase. Further, it was also found out that the Li concentration at the electrode/electrolyte interface increased.

Journal Articles

A New view of the tree of life

Hug, L. A.*; Baker, B. J.*; Anantharaman, K.*; Brown, C. T.*; Probst, A. J.*; Castelle, C. J.*; Butterfield, C. N.*; Hernsdorf, A. W.*; Amano, Yuki; Ise, Kotaro; et al.

Nature Microbiology (Internet), 1(5), p.16048_1 - 16048_6, 2016/05

 Times Cited Count:643 Percentile:0.02(Microbiology)

The tree of life is one of the most important organizing principles in biology. Gene surveys suggest the existence of an enormous number of branches, but even an approximation of the full scale of The Tree has remained elusive. Here, we use newly available information from genomes of uncultivated organisms, along with other published sequences, to present a new version of the Tree of life, with Bacteria, Archaea and Eukaryotes included. The depiction is both a global overview and a snapshot of the diversity within each major lineage. The results imply the predominance of bacterial diversification and underline the importance of organisms lacking isolated representatives, with substantial evolution concentrated in a major radiation of such organisms.

Journal Articles

Lithium intercalation and structural changes at the LiCoO$$_{2}$$ surface under high voltage battery operation

Taminato, So*; Hirayama, Masaaki*; Suzuki, Kota*; Tamura, Kazuhisa; Minato, Taketoshi*; Arai, Hajime*; Uchimoto, Yoshiharu*; Ogumi, Zempachi*; Kanno, Ryoji*

Journal of Power Sources, 307, p.599 - 603, 2016/03

 Times Cited Count:21 Percentile:25.56(Chemistry, Physical)

An epitaxial-film model electrode of LiCoO$$_{2}$$(104) was fabricated on SrRuO$$_{3}$$(100)/Nb:SrTiO$$_{3}$$(100) using pulsed laser deposition. The 50 nm thick LiCoO$$_{2}$$(104) film exhibited lithium (de-)intercalation activity with a first discharge capacity of 119 mAh g$$^{-1}$$ between 3.0 and 4.4 V, followed by a gradual capacity fading with subsequent charge-discharge cycles. In contrast, a 3.2 nm thick Li$$_{3}$$PO$$_{4}$$-coated film exhibited a higher intercalation capacity of 148 mAh g$$^{-1}$$ with superior cycle retention than the uncoated film. In situ surface X-ray diffraction measurements revealed a small lattice change at the coated surface during the (de-)intercalation processes compared to the uncoated surface. The surface modification of LiCoO$$_{2}$$ by the Li$$_{3}$$PO$$_{4}$$ coating could lead to improvement of the structural stability at the surface region during lithium (de-)intercalation at high voltage.

Journal Articles

Structural analysis of electrode-electrolyte interface in lithium batteries

Kanno, Ryoji*; Hirayama, Masaaki*; Suzuki, Kota*; Tamura, Kazuhisa

Hyomen Kagaku, 37(2), p.52 - 59, 2016/02

Batteries are a key technology in today's society. Since the lithium-ion configuration has been widely accepted, significant efforts have been devoted to attain high energy and power densities to produce an excellent energy storage system without any safety issue. To improve the reliability and power characteristics of batteries, deep insights into the reactions at the electrode/electrolyte interface are necessary. The model systems with epitaxial thin-film electrodes might be suitable for understanding these reactions. The in situ techniques for directly observing surface structural changes of the electrodes have been developed for surface X-ray scattering and neutron reflectivity techniques. These techniques are reviewed and future studies on the interfacial reaction in batteries will be discussed.

Journal Articles

The Role of nitric oxide in radiation-induced bystander cell-killing effect

Yokota, Yuichiro; Funayama, Tomoo; Ikeda, Hiroko; Sakashita, Tetsuya; Suzuki, Michiyo; Kobayashi, Yasuhiko

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 67, 2016/02

The role of nitric oxide (NO) in bystander effect was investigated. Human fibroblasts were irradiated with $$gamma$$-rays (LET: 0.2 keV/$$mu$$m) or carbon-ion beam (108 keV/$$mu$$m), and then, co-cultured with the non-irradiated cells. After 24 h culture, the survival rates of non-irradiated cells and the concentrations of nitrate, an oxide of NO, in the medium were measured. The survival rates of non-irradiated cells decreased in dose-dependent and radiation quality-independent manners. Negative relationships between survival rates and nitrite concentrations existed, indicating the amounts of produced NO are an important determinant of bystander effects. Next, a reagent producing two molecules of NO in a half-life of 100 min was added in the culture medium. After incubation of 24 h the survival rates of treated cells did not decrease, suggesting NO produced intracellularly has an important role to lead the bystander effect but is not the signal molecule for intercellular communication.

Journal Articles

2016 Professional Engineer (PE) test preparation course "Nuclear and Radiation Technical Disciplines"

Takahashi, Naoki; Yoshinaka, Kazuyuki; Harada, Akio; Yamanaka, Atsushi; Ueno, Takashi; Kurihara, Ryoichi; Suzuki, Soju; Takamatsu, Misao; Maeda, Shigetaka; Iseki, Atsushi; et al.

Nippon Genshiryoku Gakkai Homu Peji (Internet), 64 Pages, 2016/00

no abstracts in English

Journal Articles

Interfacial analysis of surface-coated LiMn$$_{2}$$O$$_{4}$$ epitaxial thin film electrode for lithium batteries

Suzuki, Kota*; Hirayama, Masaaki*; Kim, K.-S.*; Taminato, So*; Tamura, Kazuhisa; Son, J.-Y.*; Mizuki, Junichiro; Kanno, Ryoji*

Journal of the Electrochemical Society, 162(13), p.A7083 - A7090, 2015/08

 Times Cited Count:8 Percentile:65.9(Electrochemistry)

The effects of surface coatings on LiMn$$_{2}$$O$$_{4}$$ were investigated using LiMn$$_{2}$$O$$_{4}$$ epitaxial thin films with a thickness of 30 nm. Bare and surface-coated LiMn$$_{2}$$O$$_{4}$$ epitaxial thin films were synthesized on SrTiO$$_{3}$$(111) substrates using a pulsed laser deposition method. The surface coating, which was formed using the solid electrolyte Li$$_{3}$$PO$$_{4}$$ and had a thickness of 3 nm, improved the reversibility of the electrochemical reactions undergone by the LiMn$$_{2}$$O$$_{4}$$ epitaxial thin films. The changes induced in the surface structure were maintained during battery operation; in contrast, the bare LiMn$$_{2}$$O$$_{4}$$ thin film exhibited structural degradation and Mn dissolution. The structural changes induced in the coated electrode and the increase in its surface stability were intrinsic effects of the Li$$_{3}$$PO$$_{4}$$ coating and improved the electrochemical performance of the LiMn$$_{2}$$O$$_{4}$$ thin-film electrode.

Journal Articles

Cesium sorption and desorption behavior of clay minerals

Yokoyama, Shingo*; Nakata, Kotaro*; Suzuki, Shinichi

Nendo Kagaku, 54(1), p.28 - 35, 2015/08

no abstracts in English

Journal Articles

Precise determination of $$^{12}_{Lambda}$$C level structure by $$gamma$$-ray spectroscopy

Hosomi, Kenji; Ma, Y.*; Ajimura, Shuhei*; Aoki, Kanae*; Dairaku, Seishi*; Fu, Y.*; Fujioka, Hiroyuki*; Futatsukawa, Kenta*; Imoto, Wataru*; Kakiguchi, Yutaka*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2015(8), p.081D01_1 - 081D01_8, 2015/08

 Times Cited Count:12 Percentile:28.45(Physics, Multidisciplinary)

Level structure of the $$^{12}_{Lambda}$$C hypernucleus was precisely determined by means of $$gamma$$-ray spectroscopy. We identified four $$gamma$$-ray transitions via the $$^{12}$$C$$(pi^{+},K^{+}gamma)$$ reaction using a germanium detector array, Hyperball2. The spacing of the ground-state doublet $$(2^{-}, 1^{-}_{1})$$ was measured to be $$161.5pm0.3$$(stat)$$pm0.3$$ (syst)keV from the direct $$M1$$ transition. Excitation energies of the $$1^{-}_{2}$$ and $$1^{-}_{3}$$ states were measured to be $$2832pm3pm4$$, keV and $$6050pm8pm7$$, keV, respectively. The obtained level energies provide definitive references for the reaction spectroscopy of $$Lambda$$ hypernuclei.

Journal Articles

Superdeformation in $$^{35}$$S

Go, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Kobayashi, Motoki*; Kisamori, Keiichi*; Takaki, Motonobu*; Miya, Hioyuki*; Ota, Shinsuke*; Michimasa, Shinichiro*; Shimoura, Susumu*; et al.

JPS Conference Proceedings (Internet), 6, p.030005_1 - 030005_4, 2015/06

Journal Articles

Responses of the salt chemotaxis learning in ${it C. elegans}$ mutants to microbeam irradiation

Sakashita, Tetsuya; Suzuki, Michiyo; Hattori, Yuya; Ikeda, Hiroko; Muto, Yasuko*; Yokota, Yuichiro; Funayama, Tomoo; Hamada, Nobuyuki*; Shirai, Kana*; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 74, 2015/03

An increasing body of data indicates that ionizing radiation affects the nervous system and alters its function. Recently, we reported that chemotaxis of ${it C. elegans}$ during the salt chemotaxis learning (SCL), that is conditioned taste aversion to NaCl, was modulated by carbon ion irradiation, i.e. accelerated decrease in chemotaxis to NaCl during the SCL. However, we had no direct evidence for the interaction of ionizing radiation with the central neuronal tissue (nerve ring) in ${it C. elegans}$. Microbeam irradiation is useful to analyze direct radiation effects at a cellular or tissue level. Thus, we applied the microbeam irradiation of the ${it C. elegans}$ nerve ring and examined the effect on the SCL.

Journal Articles

Effects of carbon-ion microbeam irradiation on locomotion and pharyngeal pumping motion in $textit{C. elegans}$

Suzuki, Michiyo; Hattori, Yuya; Sakashita, Tetsuya; Funayama, Tomoo; Yokota, Yuichiro; Ikeda, Hiroko; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 88, 2015/03

Journal Articles

Bystander effect mediated by nitric oxide depends on irradiation dose but not on radiation quality

Yokota, Yuichiro; Funayama, Tomoo; Ikeda, Hiroko; Sakashita, Tetsuya; Suzuki, Michiyo; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 75, 2015/03

We investigated the bystander effect induced by $$gamma$$-rays or carbon ions and analyzed the role of nitric oxide (NO) in the effect. Normal human fibroblasts were used. Cells inoculated on a porous membrane were irradiated with varying doses of $$gamma$$-rays or carbon ions. Irradiated cells were then non-contact co-cultured with non-irradiated cells for 24 h. After co-culture, the survival rates of non-irradiated bystander cells co-cultured with irradiated cells decreased with increasing dose and bottomed out at 0.5 Gy or higher doses. This indicates that the bystander effect is dependent on irradiation dose but independent of radiation quality. Next, a specific NO scavenger c-PTIO was added to the culture medium during irradiation and co-culture. This treatment prevented the reduction in survival rates of bystander cells, clearly indicating that NO has an important role in the bystander effect.

Journal Articles

Target irradiation of individual cells using focusing heavy-ion microbeam of JAEA-Takasaki, 5; Irradiation of individual cells with scanned heavy-ion microbeam

Funayama, Tomoo; Yokota, Yuichiro; Suzuki, Michiyo; Sakashita, Tetsuya; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 73, 2015/03

Using a collimating heavy-ion microbeam system, we have explored various effects of heavy-ion hit on biological materials. However, there are limitations of the collimating system in the size of the microbeam spot and in the irradiation speed that cannot be overcome in principle. Thus, we started the development of a focusing microbeam system for target-irradiating individual cells more precisely. In this year, we established the protocol for irradiating "actual" cell sample with scanned beam. In the experiment, the HeLa cells were inoculated on a CR-39 film, then place on the sample stage. The microscopic image of cells was analyzed, and the cells were irradiated with scanned neon microbeam. After irradiation, we found the correspondence of the distribution pattern of the ion hit positions and the $$gamma$$-H2AX foci on cell nuclei, indicating rapid and accurate irradiation of individual cells with the focusing heavy-ion microbeam.

Journal Articles

Mechanisms for the induction of radioadaptive response by radiation-induced bystander response

Matsumoto, Hideki*; Tomita, Masanori*; Otsuka, Kensuke*; Hatashita, Masanori*; Maeda, Munetoshi*; Funayama, Tomoo; Yokota, Yuichiro; Suzuki, Michiyo; Sakashita, Tetsuya; Ikeda, Hiroko; et al.

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 76, 2015/03

The objective of this project is to elucidate molecular mechanisms for the induction of radioadaptive response through radiation-induced bystander responses induced by irradiation with heavy ion microbeams in JAEA. We found that the adaptive response was induced by Ar (520 MeV $$^{40}$$Ar$$^{14+}$$) microbeam-irradiation of a limited number of cells, followed by the broad beam-irradiation and that the adaptive response was almost completely suppressed by the addition of carboxy-PTIO, as a nitric oxide (NO) scavenger. In addition, we found several genes induced specifically and preferentially when radioadaptive response could be induced. We confirmed that ${it iNOS}$ expression was specifically induced only when radioadaptive response could be induced. Our findings strongly suggested that radioadaptive response can be induced by NO-mediated bystander responses evoked by irradiation with heavy ion microbeams.

Journal Articles

Analysis of bystander response in 3D cultured tissue induced by heavy-ion microbeam irradiation

Tomita, Masanori*; Matsumoto, Hideki*; Otsuka, Kensuke*; Funayama, Tomoo; Yokota, Yuichiro; Suzuki, Michiyo; Sakashita, Tetsuya; Kobayashi, Yasuhiko

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 77, 2015/03

Radiation-induced bystander responses are defined as responses in cells that have not been directly targeted by radiation but are in the neighborhood of cells that have been directly exposed. In this study, we aim to clarify a role of bystander response to sustain the homeostasis of damaged tissue using heavy-ion microbeams. We established the heavy-ion microbeam irradiation method to a 3D cultured human epidermis. Using this method, a viable cell rate of the 3D cultured human epidermis irradiated with 260 MeV $$^{20}$$Ne-ion microbeams or broadbeams was analyzed by the MTT method.

163 (Records 1-20 displayed on this page)