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Journal Articles

Flow filtration/adsorption and simultaneous monitoring technologies of radiocesium $$^{137}$$Cs in river water

Enomoto, Kazuyuki*; Hoshina, Hiroyuki*; Kasai, Noboru*; Kurita, Keisuke; Ueki, Yuji*; Nagao, Yuto*; Yin, Y.-G.*; Suzui, Nobuo*; Kawachi, Naoki*; Seko, Noriaki*

Chemical Engineering Journal, 460, p.141696_1 - 141696_9, 2023/03

 Times Cited Count:1 Percentile:0.01(Engineering, Environmental)

This study develops a method that combines a radiation-grafting fibrous Cs-adsorbent filter of ammonium molybdophosphate (AMP) and a Ce:Gd$$_3$$Al$$_2$$Ga$$_3$$O$$_{12}$$ scintillator based $$gamma$$-ray detector for in situ measurements of the activity concentrations of $$^{137}$$Cs in a continuous water flow.

Journal Articles

Effect of dry-wet cycles on the relative moisture content in concrete specimen

Hosokawa, Takayuki; Yasue, Ayumu*; Kim, J.; Kurita, Keisuke; Kanematsu, Manabu*

Konkurito Kozobutsu No Hoshu, Hokyo, Appuguredo Rombun Hokokushu (CD-ROM), 22, p.113 - 118, 2022/10

no abstracts in English

Journal Articles

"Live-autoradiography" technique reveals genetic variation in the rate of Fe uptake by barley cultivars

Higuchi, Kyoko*; Kurita, Keisuke; Sakai, Takuro; Suzui, Nobuo*; Sasaki, Minori*; Katori, Maya*; Wakabayashi, Yuna*; Majima, Yuta*; Saito, Akihiro*; Oyama, Takuji*; et al.

Plants (Internet), 11(6), p.817_1 - 817_11, 2022/03

 Times Cited Count:2 Percentile:58.59(Plant Sciences)

Genetic diversity in the rate of Fe uptake by plants has not been broadly surveyed among plant species or genotypes, although plants have developed various Fe acquisition mechanisms. We adopted the "Live-autoradiography" technique with radioactive $$^{59}$$Fe to directly evaluate the uptake rate of Fe by barley cultivars from a nutrient solution containing a very low concentration of Fe. Our observations revealed that the ability to acquire Fe from the low Fe solution was not always the sole determinant of tolerance to Fe deficiency among the barley genotypes.

Journal Articles

PSTEP: Project for solar-terrestrial environment prediction

Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.

Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12

 Times Cited Count:6 Percentile:55.7(Geosciences, Multidisciplinary)

The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.

Journal Articles

Noninvasive imaging of hollow structures and gas movement revealed the gas partial-pressure-gradient-driven long-distance gas movement in the aerenchyma along the leaf blade to submerged organs in rice

Yin, Y.-G.*; Mori, Yoshinao*; Suzui, Nobuo*; Kurita, Keisuke; Yamaguchi, Mitsutaka*; Miyoshi, Yuta*; Nagao, Yuto*; Ashikari, Motoyuki*; Nagai, Keisuke*; Kawachi, Naoki*

New Phytologist, 232(5), p.1974 - 1984, 2021/12

 Times Cited Count:7 Percentile:70.91(Plant Sciences)

Rice ($$Oryza sativa$$) plants have porous or hollow organs consisting of aerenchyma, which is presumed to function as a low-resistance diffusion pathway for air to travel from the foliage above the water to submerged organs. However, gas movement in rice plants has yet to be visualized in real time. In this study involving partially submerged rice plants, the leaves emerging from the water were fed nitrogen-13-labeled nitrogen ([$$^{13}$$N]N$$_2$$) tracer gas, and the gas movement downward along the leaf blade, leaf sheath, and internode over time was monitored.

Journal Articles

Autoradiography system with phosphor powder (ZnS:Ag) for imaging radioisotope dynamics in a living plant

Kurita, Keisuke; Sakai, Takuro; Suzui, Nobuo*; Yin, Y.-G.*; Sugita, Ryohei*; Kobayashi, Natsuko*; Tanoi, Keitaro*; Kawachi, Naoki*

Japanese Journal of Applied Physics, 60(11), p.116501_1 - 116501_4, 2021/11

 Times Cited Count:1 Percentile:11.39(Physics, Applied)

Radioisotope tracer imaging is useful for studying plant physiological phenomena. In this study, we developed an autoradiography system with phosphor powder (ZnS:Ag), "Live-autoradiography", for imaging radioisotope dynamics in a living plant. This system visualizes the element migration and accumulation in intact plants continuously under a light environment. An imaging test was performed on point sources of $$^{137}$$Cs, with a radioactivity of 10-100 kBq of being observed; this indicates satisfactory system linearity between the image intensity and the radioactivity of $$^{137}$$Cs. Moreover, dynamics imaging of $$^{137}$$Cs was performed on an intact soybean plant for four days. The serial images indicated $$^{137}$$Cs accumulation in the node, vein, and growing point of the plant. The developed system can be used for studying plant physiological phenomena and can be employed for quantitative measurement of radionuclides.

Journal Articles

Non-invasive $$^{11}$$C-imaging revealed the spatiotemporal variability in the translocation of photosynthates into strawberry fruits in response to increasing daylight integrals at leaf surface

Miyoshi, Yuta*; Hidaka, Kota*; Yin, Y.-G.*; Suzui, Nobuo*; Kurita, Keisuke; Kawachi, Naoki*

Frontiers in Plant Science (Internet), 12, p.688887_1 - 688887_14, 2021/07

 Times Cited Count:10 Percentile:82.69(Plant Sciences)

In this study, $$^{11}$$C-photosynthate translocation into strawberry fruits in individual plants was visualized non-invasively and repeatedly using a positron emission tracer imaging system (PETIS) to assess the spatiotemporal variability in the translocation dynamics in response to increasing daylight integrals. This is the first study to use $$^{11}$$C-radioisotopes to clarify the spatiotemporal variability in photosynthate translocation from source leaves to individual sink fruits in vivo in response to increasing daylight integrals at a high spatiotemporal resolution.

Journal Articles

Application of OpenPET as 3-D imaging device of carbon distribution in fruit

Kurita, Keisuke; Miyoshi, Yuta*; Nagao, Yuto*; Yamaguchi, Mitsutaka*; Suzui, Nobuo*; Yin, Y.-G.*; Ishii, Satomi*; Kawachi, Naoki*; Hidaka, Kota*; Yoshida, Eiji*; et al.

QST-M-29; QST Takasaki Annual Report 2019, P. 106, 2021/03

Journal Articles

Neutron Radiography Facility; TNRF and CNRF

Kurita, Keisuke; Iikura, Hiroshi

Hamon, 31(1), p.11 - 13, 2021/02

no abstracts in English

Journal Articles

Measurements of intensity of produced light in water during irradiations of electron beams with energies above and below the Cerenkov-light threshold

Yamamoto, Seiichi*; Nagao, Yuto*; Kurita, Keisuke; Yamaguchi, Mitsutaka*; Kawachi, Naoki*

Journal of Instrumentation (Internet), 16(1), p.P01007_1 - P01007_9, 2021/01

 Times Cited Count:0 Percentile:0(Instruments & Instrumentation)

Luminescence of water during irradiation with particles having energies below the Cerenkov-light threshold was recently found for various types of radiations. However, the relation between the intensities of Cerenkov light and of the luminescence of water at the beam energy below the Cherenkov threshold is not well known. To clarify this point, we measured the produced light irradiating a water sample with electron beams having maximum energies above and below the Cerenkov-light threshold.

Journal Articles

A Sensitive method for Sr-90 analysis by accelerator mass spectrometry

Sasa, Kimikazu*; Honda, Maki; Hosoya, Seiji*; Takahashi, Tsutomu*; Takano, Kenta*; Ochiai, Yuta*; Sakaguchi, Aya*; Kurita, Saori*; Satou, Yukihiko; Sueki, Keisuke*

Journal of Nuclear Science and Technology, 58(1), p.72 - 79, 2021/01

 Times Cited Count:8 Percentile:77.61(Nuclear Science & Technology)

Journal Articles

Non-invasive imaging of radiocesium dynamics in a living animal using a positron-emitting $$^{127}$$Cs tracer

Suzui, Nobuo*; Shibata, Takuya; Yin, Y.-G.*; Funaki, Yoshihito*; Kurita, Keisuke; Hoshina, Hiroyuki*; Yamaguchi, Mitsutaka*; Fujimaki, Shu*; Seko, Noriaki*; Watabe, Hiroshi*; et al.

Scientific Reports (Internet), 10, p.16155_1 - 16155_9, 2020/10

 Times Cited Count:2 Percentile:28.65(Multidisciplinary Sciences)

Journal Articles

Visualising spatio-temporal distributions of assimilated carbon translocation and release in root systems of leguminous plants

Yin, Y.-G.*; Suzui, Nobuo*; Kurita, Keisuke; Miyoshi, Yuta*; Unno, Yusuke*; Fujimaki, Shu*; Nakamura, Takuji*; Shinano, Takuro*; Kawachi, Naoki*

Scientific Reports (Internet), 10, p.8446_1 - 8446_11, 2020/06

 Times Cited Count:10 Percentile:66.36(Multidisciplinary Sciences)

The release of rhizodeposits differs depending on the root position and is closely related to the assimilated carbon (C) supply. Therefore, quantifying the C partitioning over a short period may provide crucial information for clarifying root-soil carbon metabolism. A non-invasive method for visualising the translocation of recently assimilated C into the root system inside the rhizobox was established using $$^{11}$$CO$$_{2}$$ labelling and the positron-emitting tracer imaging system. The spatial distribution of recent $$^{11}$$C-photoassimilates translocated and released in the root system and soil were visualised for white lupin ($$Lupinus albus$$) and soybean ($$Glycine max$$). Our method enabled the quantification of the spatial C allocations in roots and soil, which may help to elucidate the relationship between C metabolism and nutrient cycling at specific locations of the root-soil system in response to environmental conditions over relatively short periods.

Journal Articles

On-line rapid purification of [$$^{13}$$N]N$$_2$$ gas for visualization of nitrogen fixation and translocation in nodulated soybean

Yin, Y.-G.*; Ishii, Satomi*; Suzui, Nobuo*; Igura, Masato*; Kurita, Keisuke; Miyoshi, Yuta*; Nagasawa, Naotsugu*; Taguchi, Mitsumasa*; Kawachi, Naoki*

Applied Radiation and Isotopes, 151, p.7 - 12, 2019/09

 Times Cited Count:6 Percentile:60.63(Chemistry, Inorganic & Nuclear)

Accurate analysis of N fixation in leguminous crops requires determination of N utilization within an intact plant$$;$$ however, most approaches require tissue disassembly. We developed a simple and rapid technique to generate high-purity and high-yield [$$^{13}$$N]N$$_2$$ gas and obtained real-time images of N fixation in an intact soybean plant. The purification efficiency was $$sim$$ 81.6% after decay correction.

Journal Articles

Transient ionization of the mesosphere during auroral breakup; Arase satellite and ground-based conjugate observations at Syowa Station

Kataoka, Ryuho*; Nishiyama, Takanori*; Tanaka, Yoshimasa*; Kadokura, Akira*; Uchida, Herbert Akihito*; Ebihara, Yusuke*; Ejiri, Mitsumu*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Sato, Kaoru*; et al.

Earth, Planets and Space (Internet), 71, p.9_1 - 9_10, 2019/01

 Times Cited Count:7 Percentile:40.2(Geosciences, Multidisciplinary)

Transient ionization of the mesosphere was detected at around 65 km altitude during the isolated auroral expansion occurred at 2221-2226 UT on June 30, 2017. A general-purpose Monte Carlo particle transport code PHITS suggested that significant ionization is possible in the middle atmosphere due to auroral X-rays from the auroral electrons of $$<$$10 keV.

Journal Articles

Physical design of JT-60 Super Upgrade

Nagashima, Keisuke; Kikuchi, Mitsuru; Kurita, Genichi; Ozeki, Takahisa; Aoyagi, Tetsuo; Ushigusa, Kenkichi; Neyatani, Yuzuru; Kubo, Hirotaka; Mori, Kensuke*; Nakagawa, Shoji*; et al.

Fusion Engineering and Design, 36(2-3), p.325 - 342, 1997/05

 Times Cited Count:1 Percentile:14.51(Nuclear Science & Technology)

no abstracts in English

Oral presentation

Critical beta analyses of low aspect ratio tokamak

Kurita, Genichi; Aiba, Nobuyuki; Tobita, Kenji; Nishio, Satoshi; Nagashima, Keisuke

no journal, , 

We obtain the critical beta for the up-down symmetric double-null equilibria against the position of conformal conducting wall in two cases; one is fixed plasma current profile case and another is varied plasma current profile case taking a bootstrap current into account. To obtain normalized beta value, bN=4.3, assumed in Slim-CS tokamak, we must put the conducting wall at r=1.2a and r=1.34a, where a is the plasma minor radius, for former and latter cases, respectively. The advantage of latter case comes from the higher minimum safety factor value due to larger plasma bootstrap current derived by the increased plasma pressure. If we consider the effect of edge pedestal plasma pressure, the critical beta can be increased. In this study, only the n=1 mode, which is considered to be most dangerous one, is investigated.

Oral presentation

Critical beta analyses of low aspect ratio tokamak, 2

Kurita, Genichi; Tobita, Kenji; Asakura, Nobuyuki; Aiba, Nobuyuki; Nagashima, Keisuke

no journal, , 

It is necessary to obtain the stable high beta plasma in order to realize the economically superior magnetically confined fusion reactor. In these analyses, we mainly investigate the effect of plasma pressure pedestal near plasma edge region considering the bootstrap current effect due to edge plasma pressure pedestal. The following results are obtained. Increase of edge plasma pressure induces a rise of critical beta because of reduction of internal plasma pressure gradient, until the edge plasma pressure gradient and bootstrap current induces the new instability near the plasma edge. For comparatively peaked plasma pressure profiles, we have another higher door-knob like stable region near the maximum critical beta region.

Oral presentation

Systematic evaluation of cultivation using plant radiotracer imaging techniques; For establishment of "Nuclear Agriculture"

Fujimaki, Shu; Kawachi, Naoki; Suzui, Nobuo; Ishii, Satomi; Yin, Y.-G.; Kurita, Keisuke

no journal, , 

no abstracts in English

Oral presentation

Non-invasive imaging of sodium and zinc in intact plants using commercially available radioisotopes

Suzui, Nobuo; Yin, Y.-G.; Ishii, Satomi; Kurita, Keisuke; Kawachi, Naoki; Fujimaki, Shu

no journal, , 

no abstracts in English

53 (Records 1-20 displayed on this page)