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Journal Articles

Partial breakdown of translation symmetry at a structural quantum critical point associated with a ferroelectric soft mode

Ishii, Yui*; Yamamoto, Arisa*; Sato, Naoki*; Nambu, Yusuke*; Kawamura, Seiko; Murai, Naoki; Ohara, Koji*; Kawaguchi, Shogo*; Mori, Takao*; Mori, Shigeo*

Physical Review B, 106(13), p.134111_1 - 134111_7, 2022/10

 Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)

Journal Articles

Environmental effects on layer-dependent dynamics of Dirac fermions in quasicrystalline bilayer graphene

Zhao, Y.*; Suzuki, T.*; Iimori, T.*; Kim, H.-W.*; Ahn, J. R.*; Horio, Masafumi*; Sato, Yusuke*; Fukaya, Yuki; Kanai, T.*; Okazaki, K.*; et al.

Physical Review B, 105(11), p.115304_1 - 115304_8, 2022/03

 Times Cited Count:1 Percentile:18.86(Materials Science, Multidisciplinary)

no abstracts in English

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:52.8(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

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

 Times Cited Count:30 Percentile:96.87(Astronomy & Astrophysics)

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Journal Articles

Comparison of antioxidative effects between radon and thoron inhalation in mouse organs

Kobashi, Yusuke*; Kataoka, Takahiro*; Kanzaki, Norie; Ishida, Tsuyoshi*; Sakoda, Akihiro; Tanaka, Hiroshi; Ishimori, Yuu; Mitsunobu, Fumihiro*; Yamaoka, Kiyonori*

Radiation and Environmental Biophysics, 59(3), p.473 - 482, 2020/08

 Times Cited Count:5 Percentile:41.71(Biology)

Radon therapy has been traditionally performed globally for oxidative stress-related diseases. Many researchers have studied the beneficial effects of radon exposure in living organisms. However, the effects of thoron, a radioisotope of radon, have not been fully examined. In this study, we aimed to compare the biological effects of radon and thoron inhalation on mouse organs with a focus on oxidative stress. Male BALB/c mice were randomly divided into 15 groups: sham inhalation, radon inhalation at a dose of 500 Bq/m$$^{3}$$ or 2000 Bq/m$$^{3}$$, and thoron inhalation at a dose of 500 Bq/m$$^{3}$$ or 2000 Bq/m$$^{3}$$ were carried out. Immediately after inhalation, mouse tissues were excised for biochemical assays. The results showed a significant increase in superoxide dismutase and total glutathione, and a significant decrease in lipid peroxide following thoron inhalation under several conditions. Additionally, similar effects were observed for different doses and inhalation times between radon and thoron. Our results suggest that thoron inhalation also exerts antioxidative effects against oxidative stress in organs. However, the inhalation conditions should be carefully analyzed because of the differences in physical characteristics between radon and thoron.

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JRR-2, JRR-3 and hot laboratory facilities

Tobita, Minoru*; Haraga, Tomoko; Sasaki, Takayuki*; Seki, Kotaro*; Omori, Hiroyuki*; Kochiyama, Mami; Shimomura, Yusuke; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2019-016, 72 Pages, 2020/02

JAEA-Data-Code-2019-016.pdf:2.67MB

In the future, radioactive wastes which generated from research and testing reactors in Japan Atomic Energy Agency are planning to be buried for the near surface disposal. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes by the time it starts disposal. In order to contribute to this work, we collected and analyzed the samples generated from JRR-2, JRR-3 and Hot laboratory facilities. In this report, we summarized the radioactivity concentrations of 25 radionuclides ($$^{3}$$H, $$^{14}$$C, $$^{36}$$Cl, $$^{60}$$Co, $$^{63}$$Ni, $$^{90}$$Sr, $$^{94}$$Nb, $$^{93}$$Mo, $$^{99}$$Tc, $$^{108m}$$Ag, $$^{126}$$Sn, $$^{129}$$I, $$^{137}$$Cs, $$^{152}$$Eu, $$^{154}$$Eu, $$^{233}$$U, $$^{234}$$U, $$^{238}$$U, $$^{238}$$Pu, $$^{239}$$Pu, $$^{240}$$Pu, $$^{241}$$Pu, $$^{241}$$Am, $$^{243}$$Am, $$^{244}$$Cm) which were obtained from radiochemical analysis of those samples.

Journal Articles

Repeatability and reproducibility of measurements of low dissolved radiocesium concentrations in freshwater using different pre-concentration methods

Kurihara, Momo*; Yasutaka, Tetsuo*; Aono, Tatsuo*; Ashikawa, Nobuo*; Ebina, Hiroyuki*; Iijima, Takeshi*; Ishimaru, Kei*; Kanai, Ramon*; Karube, Jinichi*; Konnai, Yae*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 322(2), p.477 - 485, 2019/11

 Times Cited Count:2 Percentile:21.95(Chemistry, Analytical)

We assessed the repeatability and reproducibility of methods for determining low dissolved radiocesium concentrations in freshwater in Fukushima. Twenty-one laboratories pre-concentrated three of 10 L samples by five different pre-concentration methods (prussian-blue-impregnated filter cartridges, coprecipitation with ammonium phosphomolybdate, evaporation, solid-phase extraction disks, and ion-exchange resin columns), and activity of radiocesium was measured. The z-scores for all of the $$^{137}$$Cs results were within $$pm$$2, indicating that the methods were accurate. The relative standard deviations (RSDs) indicating the variability in the results from different laboratories were larger than the RSDs indicating the variability in the results from each separate laboratory.

Journal Articles

Track structure study for energy dependency of electrons and X-rays on DNA double-strand break induction

Yachi, Yoshie*; Yoshii, Yuji*; Matsuya, Yusuke; Mori, Ryosuke*; Oikawa, Joma*; Date, Hiroyuki*

Scientific Reports (Internet), 9(1), p.17649_1 - 17649_8, 2019/11

 Times Cited Count:4 Percentile:32.42(Multidisciplinary Sciences)

Radiation weighting factor for photon and electron is defined as 1.0 independently these energies. However, it should be noted that the biological effects after 29 kVp X-rays is relative higher than standard 200 kVp X-rays at the endpoint of ${it in vitro}$. And it is of importance to evaluate electrons generated via interaction of photons with matter. Here, we evaluated the energy concentration along electron track (dose-mean lineal energy) on chromosome (micron-meter) scales by Monte Carlo simulation, and measured the DNA double-strand breaks (DSBs) induction. From the cell experiments, the DSBs induction after diagnostic X-rays exposure (60-100 kVp) is higher than those with therapeutic X-rays (6 MV). In the relation between the dose-mean lineal energy and the number of DSBs, it was shown that lower energy photons might induce more biological impact due to the interaction by low energy electron. This study implies that radiation weighting factor for photon and electron should not be unity.

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JRR-2 and JRR-3 facilities

Haraga, Tomoko; Shimomura, Yusuke; Mitsukai, Akina; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2019-004, 48 Pages, 2019/10

JAEA-Data-Code-2019-004.pdf:4.67MB

In the future, radioactive wastes which generated from research and testing reactors in Japan Atomic Energy Agency are planning to be buried for the near surface disposal. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes by the time it starts disposal. In order to contribute to this work, we collected and analyzed the samples generated from JRR-2 and JRR-3. In this report, we summarized the radioactivity concentrations of 19 radionuclides ($$^{3}$$H, $$^{14}$$C, $$^{36}$$Cl, $$^{60}$$Co, $$^{63}$$Ni, $$^{90}$$Sr, $$^{94}$$Nb, $$^{99}$$Tc, $$^{rm 108m}$$Ag, $$^{129}$$I, $$^{137}$$Cs, $$^{152}$$Eu, $$^{154}$$Eu, $$^{234}$$U, $$^{238}$$U, $$^{238}$$Pu, $$^{239+240}$$Pu, $$^{241}$$Am, $$^{244}$$Cm) which were obtained from radiochemical analysis of those samples.

Journal Articles

Extraction behavior of Mo and W from H$$_{2}$$SO$$_{4}$$ and HF/HCl solutions into toluene with Aliquat336; Sulfate and fluoride complex formation of Mo and W towards chemical studies of seaborgium (Sg)

Toyoshima, Atsushi; Mitsukai, Akina; Tsukada, Kazuaki; Oe, Kazuhiro*; Haba, Hiromitsu*; Komori, Yukiko*; Murakami, Masashi; Kaneya, Yusuke*; Sato, Daisuke*; Asai, Masato; et al.

Journal of Radioanalytical and Nuclear Chemistry, 317(1), p.421 - 430, 2018/07

 Times Cited Count:1 Percentile:11.6(Chemistry, Analytical)

We have studied extraction behavior of group-6 elements Mo and W to search for suitable conditions for an on-line extraction experiment of their heavier homolog, seaborgium (Sg). Batch-wise extraction of carrier-free radiotracers $$^{93m}$$Mo and $$^{177,179,181}$$W were carried out from 0.10 - 8.6 M H$$_{2}$$SO$$_{4}$$ and 1.0$$times$$10$$^{-4}$$ - 5.0 M HF/1.0 M HCl into toluene with a quaternary ammonium compound, Aliquat336. Anionic sulfate complexes of Mo and W with charge - 2 were extracted with Aliquat336 from H$$_{2}$$SO$$_{4}$$ solutions with concentrations of [H$$_{2}$$SO$$_{4}$$] $$>$$ 2 M. In HF/1.0 M HCl, oxyfluoro complexes of Mo and W with charge - 1 were interpreted to be formed and extracted with Aliquat336. From these results, favorable conditions for the extraction of Sg are discussed.

Journal Articles

Comparative effects of radon inhalation according to mouse strain and cisplatin dose in a cisplatin-induced renal damage model

Sasaoka, Kaori*; Kataoka, Takahiro*; Kanzaki, Norie; Kobashi, Yusuke*; Sakoda, Akihiro; Ishimori, Yuu; Yamaoka, Kiyonori*

Pakistan Journal of Zoology, 50(3), p.1157 - 1170, 2018/06

 Times Cited Count:2 Percentile:17.77(Zoology)

Cisplatin (CDDP) is widely used for treating solid cancers; however, it induces nephrotoxicity caused by oxidative stress. Here, we investigated whether radon inhalation has different effects against CDDP induced renal injury in two mouse strains differing in radiosensitivity, and determined the appropriate dose of CDDP combined with radon inhalation for highly radiosensitive mice. CDDP was administered at 20 mg/kg weight to C57BL/6J and BALB/c mice after radon inhalation at 1000 Bq/m$$^{3}$$ and 2000 Bq/m$$^{3}$$ for 24 h. Radon inhalation had a slight positive effect against CDDP toxicity in C57BL/6J mice with respect to improved hair condition, whereas radon inhalation exacerbated CDDP-induced toxicity in BALB/c mice. When BALB/c mice were treated with a lower dose of CDDP (15 mg/kg) after 1000 Bq/m$$^{3}$$ radon inhalation, the creatinine level was reduced and the superoxide dismutase content was increased. The supportive effect of radon inhalation shows its good potential as a candidate treatment to alleviate CDDP-induced renal damage.

Journal Articles

Knowledge discovery of suppressive effect of disease and increased anti-oxidative function by low-dose radiation using self-organizing map

Kanzaki, Norie; Kataoka, Takahiro*; Kobashi, Yusuke*; Yunoki, Yuto*; Ishida, Tsuyoshi*; Sakoda, Akihiro; Ishimori, Yuu; Yamaoka, Kiyonori*

Radioisotopes, 67(2), p.43 - 57, 2018/02

We previously reported that low-dose radiation induces the anti-oxidative function in many organ systems of mice. This results in the suppression of several kinds of oxidative stress-induced damage. This study was conducted with the objective of revealing the health effects of low-dose radiation obtained from our previous reports and searching for a new treatment based on low-dose radiation, such as radon therapy. We extracted the characteristics of the effects of low dose radiation suppressing diseases and enhancing the anti-oxidative function using fuzzy answer by self-organizing map (SOM) based on mutual knowledge. The relationship between the suppressive effect and increased antioxidative function was shown in our result, and the concentration dependence of the effect against pain was shown on the output map. Although the effect against other organs depending on concentration was unpredictable, our results indicate that low-dose radiation may also be suitable for treatment of liver disease and brain disease.

JAEA Reports

Radioactivity analysis of metal samples taken from pipes of the Fugen, 5

Haraga, Tomoko; Tobita, Minoru*; Takahashi, Shigemi*; Seki, Kotaro*; Izumo, Sari; Shimomura, Yusuke; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2016-017, 53 Pages, 2017/02

JAEA-Data-Code-2016-017.pdf:3.17MB

Fugen Nuclear Power Station was shut down and now is under decommissioning. Many radioactivity concentration data of dismantled materials have to be accumulated to calculate the scaling factors of radioactive wastes and to verify that the cleared dismantled materials conform to the clearance levels. A simple and rapid radioactivity determination method for radioactive waste samples was developed by Department of Decommissioning and Waste Management. For its demonstration, the simple and rapid radioactivity determination method was applied to metal samples, which were taken from dismantled pipes in contact with heavy water or carbon dioxide gas of Fugen. This report summarizes the radioactivity data obtained from the analysis of those samples.

Journal Articles

Complex chemistry with complex compounds

Eichler, R.*; Asai, Masato; Brand, H.*; Chiera, N. M.*; Di Nitto, A.*; Dressler, R.*; D$"u$llmann, Ch. E.*; Even, J.*; Fangli, F.*; Goetz, M.*; et al.

EPJ Web of Conferences, 131, p.07005_1 - 07005_7, 2016/12

 Times Cited Count:2 Percentile:73.04

In recent years gas-phase chemical studies assisted by physical pre-separation allowed for the productions and investigations of fragile single molecular species of superheavy elements. The latest highlight is the formation of very volatile hexacarbonyl compound of element 106, Sg(CO)$$_{6}$$. Following this success, second-generation experiments were performed to measure the first bond dissociation energy between the central metal atom and the surrounding ligand. The method using a tubular decomposition reactor was developed and successfully applied to short-lived Mo(CO)$$_{6}$$, W(CO)$$_{6}$$, and Sg(CO)$$_{6}$$.

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:14 Percentile:66.75(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

Development of a new continuous dissolution apparatus with a hydrophobic membrane for superheavy element chemistry

Oe, Kazuhiro*; Attallah, M. F.*; Asai, Masato; Goto, Naoya*; Gupta, N. S.*; Haba, Hiromitsu*; Huang, M.*; Kanaya, Jumpei*; Kaneya, Yusuke*; Kasamatsu, Yoshitaka*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1317 - 1320, 2015/02

 Times Cited Count:8 Percentile:61(Chemistry, Analytical)

A new technique for continuous dissolution of nuclear reaction products transported by a gas-jet system was developed for superheavy element (SHE) chemistry. In this technique, a hydrophobic membrane is utilized to separate an aqueous phase from the gas phase. With this technique, the dissolution efficiencies of short-lived radionuclides of $$^{91m,93m}$$Mo and $$^{176}$$W were measured. Yields of more than 80% were observed for short-lived radionuclides at aqueous-phase flow rates of 0.1-0.4 mL/s. The gas flow-rate had no influence on the dissolution efficiency within the studied flow range of 1.0-2.0 L/min. These results show that this technique is applicable for on-line chemical studies of SHEs in the liquid phase.

Journal Articles

Unique Fermi surface and emergence of charge density wave in EuGa$$_4$$ and EuAl$$_4$$

Nakamura, Ai*; Hiranaka, Yuichi*; Hedo, Masato*; Nakama, Takao*; Miura, Yasunao*; Tsutsumi, Hiroki*; Mori, Akinobu*; Ishida, Kazuhiro*; Mitamura, Katsuya*; Hirose, Yusuke*; et al.

JPS Conference Proceedings (Internet), 3, p.011012_1 - 011012_6, 2014/06

Journal Articles

Fermi surface and magnetic properties of antiferromagnet EuBi$$_3$$

Nakamura, Ai*; Hiranaka, Yuichi*; Hedo, Masato*; Nakama, Takao*; Tatetsu, Yasutomi*; Maehira, Takahiro*; Miura, Yasunao*; Mori, Akinobu*; Tsutsumi, Hiroki*; Hirose, Yusuke*; et al.

Journal of the Physical Society of Japan, 82(12), p.124708_1 - 124708_6, 2013/12

 Times Cited Count:18 Percentile:72.71(Physics, Multidisciplinary)

Journal Articles

Magnetic and Fermi surface properties of EuGa$$_4$$

Nakamura, Ai*; Hiranaka, Yuichi*; Hedo, Masato*; Nakama, Takao*; Miura, Yasunao*; Tsutsumi, Hiroki*; Mori, Akinobu*; Ishida, Kazuhiro*; Mitamura, Katsuya*; Hirose, Yusuke*; et al.

Journal of the Physical Society of Japan, 82(10), p.104703_1 - 104703_10, 2013/10

 Times Cited Count:32 Percentile:80.72(Physics, Multidisciplinary)

Journal Articles

Electrical and magnetic properties of quasicrystal approximants RCd$$_6$$ (R: rare earth)

Mori, Akinobu*; Ota, Hisashi*; Yoshiuchi, Shingo*; Iwakawa, Ken*; Taga, Yuki*; Hirose, Yusuke*; Takeuchi, Tetsuya*; Yamamoto, Etsuji; Haga, Yoshinori; Honda, Fuminori*; et al.

Journal of the Physical Society of Japan, 81(2), p.024720_1 - 024720_10, 2012/02

 Times Cited Count:38 Percentile:83.07(Physics, Multidisciplinary)

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