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Journal Articles

Dynamics of proteins with different molecular structures under solution condition

Inoue, Rintaro*; Oda, Takashi*; Nakagawa, Hiroshi; Tominaga, Taiki*; Saio, Tomohide*; Kawakita, Yukinobu; Shimizu, Masahiro*; Okuda, Aya*; Morishima, Ken*; Sato, Nobuhiro*; et al.

Scientific Reports (Internet), 10, p.21678_1 - 21678_10, 2020/12

 Times Cited Count:2 Percentile:9.06(Multidisciplinary Sciences)

Incoherent quasielastic neutron scattering (iQENS) is a fascinating technique for investigating the internal dynamics of protein. However, both low flux of neutron beam and absence of analytical procedure for extracting the internal dynamics from iQENS profile have been obstacles for studying it under physiological condition (in solution). Thanks to the recent development of neutron source, spectrometer and computational technique, they enable us to decouple internal dynamics, translational and rotational diffusions from the iQENS profile. The internal dynamics of two proteins: globular domain protein (GDP) and intrinsically disordered protein (IDP) in solution were studied. It was found that the average relaxation rate of IDP was larger than that of GDP. Through the detailed analyses on their internal dynamics, it was revealed that the fraction of mobile H atoms in IDP was much higher than that in GDP. Interestingly, the fraction of mobile H atoms was closely related to the fraction of H atoms on highly solvent exposed surfaces. The iQENS study presented that the internal dynamics were governed by the highly solvent exposed amino acid residues depending upon protein molecular architectures.

Journal Articles

Spin-polarized Weyl cones and giant anomalous Nernst effect in ferromagnetic Heusler films

Sumida, Kazuki; Sakuraba, Yuya*; Masuda, Keisuke*; Kono, Takashi*; Kakoki, Masaaki*; Goto, Kazuki*; Zhou, W.*; Miyamoto, Koji*; Miura, Yoshio*; Okuda, Taiichi*; et al.

Communications Materials (Internet), 1, p.89_1 - 89_9, 2020/11

Journal Articles

Elastic and dynamical structural properties of La and Mn-doped SrTiO$$_{3}$$ studied by neutron scattering and their relation with thermal conductivities

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Murai, Naoki; Shamoto, Shinichi; Honda, Takashi*; Ikeda, Kazutaka*; Otomo, Toshiya*; Hata, Hiroto*; Eto, Takahiro*; Noda, Masaaki*; et al.

Scientific Reports (Internet), 8(1), p.9651_1 - 9651_8, 2018/06

 Times Cited Count:5 Percentile:32.99(Multidisciplinary Sciences)

Journal Articles

Effect of ionizing radiation upon dehydrated Pv11 cultured cells originated from the sleeping chironomid

Watanabe, Kazuyo*; Akitsuki, Takashi*; Shimura, Sachiko*; Gusev, O.*; Cornette, R.*; Kikawada, Takahiro*; Sakashita, Tetsuya; Funayama, Tomoo; Kobayashi, Yasuhiko; Okuda, Takashi*

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 87, 2015/03

The Sleeping Chironomid, ${it Polypedilum vanderplanki}$ can stand complete desiccation (anhydrobiosis) and also shows radio-resistance. Recently, we have generated cultured cell (Pv11) originated from ${it P. vanderplanki}$ embryo which can also stand complete dehydration. In this study, we examine the tolerance of cultured cell Pv11 against ionbeam irradiation.

Journal Articles

Tolerance of anhydrobiotic eggs of the tardigrade ${it Ramazzottius varieornatus}$ to extreme environments

Horikawa, Daiki*; Yamaguchi, Ayami*; Sakashita, Tetsuya; Tanaka, Daisuke*; Hamada, Nobuyuki*; Yukuhiro, Fumiko*; Kuwahara, Hirokazu*; Kunieda, Takekazu*; Watanabe, Masahiko*; Nakahara, Yuichi*; et al.

Astrobiology, 12(4), p.283 - 289, 2012/04

 Times Cited Count:23 Percentile:70.77(Astronomy & Astrophysics)

We examined the hatchability of hydrated and anhydrobiotic eggs of the tardigrade ${it Ramazzottius varieornatus}$ to hatch after ionizing irradiation (helium ions), extremely low and high temperatures, and high vacuum. Anhydrobiotic eggs (50% lethal dose; 1690 Gy) were substantially more radioresistant than hydrated ones (50% lethal dose; 509 Gy). Anhydrobiotic eggs also have a broader temperature resistance compared with hydrated ones. Over 70% of the anhydrobiotic eggs treated at high and low temperatures, but all of the hydrated eggs failed to hatch. After exposure to high vacuum conditions, the hatchability of the anhydrobiotic eggs was comparable to that of untreated control eggs.

Journal Articles

Anhydrobiosis-associated nuclear DNA damage and repair in the Sleeping Chironomid; Linkage with radioresistance

Gusev, O.*; Nakahara, Yuichi*; Vanyagina, V.*; Malutina, L.*; Cornette, R.*; Sakashita, Tetsuya; Hamada, Nobuyuki*; Kikawada, Takahiro*; Kobayashi, Yasuhiko; Okuda, Takashi*

PLoS ONE (Internet), 5(11), p.e14008_1 - e14008_9, 2010/11

 Times Cited Count:48 Percentile:74.65(Multidisciplinary Sciences)

Anhydrobiotic chironomid larvae can withstand prolonged complete desiccation as well as other external stresses including ionizing radiation. To understand the cross-tolerance mechanism, we have analyzed the damage and repair in the nuclear DNA using DNA comet assays and gene expression in relation to anhydrobiosis and radiation. We found that dehydration causes alterations in chromatin structure and a severe fragmentation of nuclear DNA in the cells of the larvae despite successful anhydrobiosis. Furthermore, while the larvae have restored physiological activity within an hour following rehydration, nuclear DNA restoration typically took 72 to 96 h.

Journal Articles

Development of apparatus for electron irradiation and in-situ I-V characteristics measurements for space solar cells

Fumon, Takashi*; Kobayashi, Ippei*; Oshima, Takeshi; Sato, Shinichiro; Okuda, Shuichi*; Taniguchi, Ryoichi*; Iwase, Akihiro*

Proceedings of the 8th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-8), p.203 - 206, 2008/12

We developed an apparatus for electron irradiation and in-situ current-voltage (I-V) characteristics measurements for space solar cells. The apparatus was interfaced to an electron linear accelerator at Radiation Research Center of Osaka Prefecture University. By using this apparatus, the electron irradiation with the energies from 6 MeV to 12 MeV can be performed at various temperatures from -196 $$^{circ}$$C to 100 $$^{circ}$$C. In-situ I-V characteristic measurements are also possible at the temperature from -196 $$^{circ}$$C to 100 $$^{circ}$$C. As a first demonstration using this apparatus, we performed two experiments. First, I-V characteristics of a Si solar cell were measured at room temperature and at low temperature. Secondly, the Si solar cell was irradiated with 10 MeV electrons and I-V characteristics were measured at room temperature. The experimental result was compared with those for 1 MeV electron irradiation and 10 MeV proton irradiation.

Journal Articles

Establishment of a rearing system of the extremotolerant tardigrade ${it Ramazzottius varieornatus}$; A New model animal for astrobiology

Horikawa, Daiki*; Kunieda, Takekazu*; Abe, Wataru*; Watanabe, Masahiko*; Nakahara, Yuichi*; Yukuhiro, Fumiko*; Sakashita, Tetsuya; Hamada, Nobuyuki*; Wada, Seiichi*; Funayama, Tomoo; et al.

Astrobiology, 8(3), p.549 - 556, 2008/06

 Times Cited Count:78 Percentile:89.78(Astronomy & Astrophysics)

We report the successful rearing of the herbivorous tardigrade, ${it Ramazzottius varieornatus}$, by supplying the green alga ${it Chlorella vulgaris}$ as food. The life span was 35 d, deposited eggs required 5.7 d to hatch, and animals began to deposit eggs 9 d after hatching. The reared individuals of this species had an anhydrobiotic capacity throughout their life cycle in egg, juvenile, and adult stages. Furthermore, the reared adults in an anhydrobiotic state were tolerant of temperatures of 90$$^{circ}$$C and -196$$^{circ}$$C and exposure to 99.8% acetonitrile or irradiation with 4000 Gy $$^{4}$$He ions. Based on their life history traits and tolerance to extreme stresses, ${it R. varieornatus}$ might be a suitable model for astrobiological studies of multicellular organisms.

Journal Articles

Radiation tolerance linked to anhydrobiosis in ${it Polypedilum vanderplanki}$

Nakahara, Yuichi*; Watanabe, Masahiko*; Kikawada, Takahiro*; Fujita, Akihiko*; Horikawa, Daiki*; Okuda, Takashi*; Sakashita, Tetsuya; Funayama, Tomoo; Hamada, Nobuyuki*; Wada, Seiichi*; et al.

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 113, 2008/03

We have shown that anhydrobiotic larvae of ${it Polypedilum vanderplanki}$ have higher tolerance against both high linear energy transfer (LET) radiation than hydrated larvae. We therefore examined effects of high-LET radiation on four kinds of larvae: (1) normal hydrated (intact) larva, (2) intermediates between the anhydrobiotic and normal hydrated state, (3) almost completely dehydrated (anhydrobiotic) larvae, and (4) immediately rehydrated larvae that are assumed to have a similar molecular profile to anhydrobiotic larvae. The intermediates and immediately rehydrated larvae survived longer after high-LET radiation than intact larvae, indicating that radiation tolerance could be enhanced even in hydrated larvae. Physiological changes toward anhydrobiosis, e.g. accumulation of protectants or increasing damage repair capacity, correlate with improved radiation tolerance in hydrated larvae.

Journal Articles

Physiological changes leading to anhydrobiosis improve radiation tolerance in ${it Polypedilum vanderplanki}$ larvae

Watanabe, Masahiko*; Nakahara, Yuichi*; Sakashita, Tetsuya; Kikawada, Takahiro*; Fujita, Akihiko*; Hamada, Nobuyuki*; Horikawa, Daiki*; Wada, Seiichi*; Kobayashi, Yasuhiko; Okuda, Takashi*

Journal of Insect Physiology, 53(6), p.573 - 579, 2007/06

 Times Cited Count:20 Percentile:67.86(Entomology)

We examined effects of high-LET radiation on 4 kinds of larvae: (1) normal hydrated (intact) larva, (2) intermediates between the anhydrobiotic and normal hydrated state, (3) almost completely dehydrated (anhydrobiotic) larvae, and (4) immediately-rehydrated larvae that are assumed to have a similar molecular profile to anhydrobiotic larvae. The intermediates and immediately-rehydrated larvae survived longer after high-LET radiation than intact larvae, indicating that radiation tolerance could be enhanced even in hydrated larvae. Physiological changes toward anhydrobiosis, e.g. accumulation of protectants or increasing damage repair capacity, correlate with improved radiation tolerance in hydrated larvae. In addition, almost complete desiccation further enhanced radiation tolerance, possibly in a different way from the hydrated larvae.

JAEA Reports

Study of ageing effect of long-term storage fuel in prototype fast breeder reactor Monju

Kato, Yuko; Umebayashi, Eiji; Okimoto, Yutaka; Okuda, Eiichi; Takayama, Koichi; Ozawa, Takayuki; Maeda, Seiichiro; Matsuzaki, Masaaki; Yoshida, Eiichi; Maeda, Koji; et al.

JAEA-Research 2007-019, 56 Pages, 2007/03

JAEA-Research-2007-019.pdf:6.79MB

In order to resume the System Startup Test (SST) of Monju, replacement fuel have to be loaded in exchange for some of initial fuel now loaded in the core to compensate core reactivity lost by decay of Pu-241 in them. The replacement fuel were being stored either in sodium in an ex-vessel storage tank or in air in a storage rack for about 10 years since their fabrication. The initial fuel were irradiated during the SST which was suspended in the end of 1995 and then stayed being loaded in the sodium-circulated core. As this long-term storage and loading may deteriorate mechanical integrity of the assemblies, a study has been made thoroughly on its thermal-hydraulic, structural and material effects on them that might be caused by irradiation in the core, sodium and mechanical environment. The study has shown that the mechanical integrity of them is well maintained even with this long-term storage and loading.

Journal Articles

Effects of heavy ions and $$gamma$$-ray on the tardigrade ${it Milnesium tardigradum}$

Horikawa, Daiki*; Sakashita, Tetsuya; Katagiri, Chihiro*; Watanabe, Masahiko*; Kikawada, Takahiro*; Nakahara, Yuichi*; Hamada, Nobuyuki*; Wada, Seiichi*; Funayama, Tomoo; Higashi, Seigo*; et al.

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 116, 2007/02

no abstracts in English

Journal Articles

Radiation tolerance in the tardigrade ${it Milnesium tardigradum}$

Horikawa, Daiki*; Sakashita, Tetsuya; Katagiri, Chihiro*; Watanabe, Masahiko*; Kikawada, Takahiro*; Nakahara, Yuichi*; Hamada, Nobuyuki*; Wada, Seiichi*; Funayama, Tomoo; Higashi, Seigo*; et al.

International Journal of Radiation Biology, 82(12), p.843 - 848, 2006/12

 Times Cited Count:119 Percentile:99.15(Biology)

no abstracts in English

Journal Articles

Estimation of radiation tolerance to high LET heavy ions in an anhydrobiotic insect, ${it Polypedilum vanderplanki}$

Watanabe, Masahiko*; Sakashita, Tetsuya; Fujita, Akihiko*; Kikawada, Takahiro*; Nakahara, Yuichi*; Hamada, Nobuyuki*; Horikawa, Daiki*; Wada, Seiichi*; Funayama, Tomoo; Kobayashi, Yasuhiko; et al.

International Journal of Radiation Biology, 82(12), p.835 - 842, 2006/12

 Times Cited Count:15 Percentile:72.54(Biology)

The aim of this study is to characterize the tolerance to high-LET radiations of${it P. vanderplanki}$. Larval survival and subsequent metamorphoses were compared between anhydrobiotic (dry) and non-anhydrobiotic (wet) samples after exposure to 1 to 7000 Gy of three types of heavy ions with LET values ranging from 16.2 to 321 keV/$$mu$$m. At all LET values measured, dry larvae consistently showed greater radiation tolerance than hydrated larvae, due to the disaccharide trehalose in anhydrobiotic animals. Relative biological effectiveness (RBE) values based on the median inhibitory doses reached a maximum at 116 keV/$$mu$$m ($$^{12}$$C). Anhydrobiosis potentiates radiation tolerance in terms of larval survival, pupation and adult emergence of ${it P. vanderplanki}$ exposed to high-LET radiations. ${it P. vanderplanki}$ larvae might have more efficient DNA damage repair after radiation than other chironomid species.

Journal Articles

Biological effects of anhydrobiosis in an African chironomid, ${it Polypedilum vanderplanki}$ on radiation tolerance

Watanabe, Masahiko*; Sakashita, Tetsuya; Fujita, Akihiko*; Kikawada, Takahiro*; Horikawa, Daiki*; Nakahara, Yuichi*; Wada, Seiichi*; Funayama, Tomoo; Hamada, Nobuyuki*; Kobayashi, Yasuhiko; et al.

International Journal of Radiation Biology, 82(8), p.587 - 592, 2006/08

 Times Cited Count:32 Percentile:89.59(Biology)

The present study aims to evaluate effects of anhydrobiosis on radiation tolerance in an anhydrobiotic insect, Polypedilum vanderplanki. Larval survival (48 h), anhydrobiotic ability, metamorphosis and reproduction after exposure to 1 to 9000 Gy of $$gamma$$-rays at the larval stage were comparedbetween anhydrobiotic (dry) and normal (wet) phases. Wet larvae were killed in a dose-dependent manner at doses higher than 2000 Gy, and all died within 8 h after 4000 Gy exposure. In contrast, dry larvae survived even 5000 Gy, and some of them still tolerated 7000 Gy and were alive at 48 h after rehydration. Moreover, greater radiotolerance of dry larva, compared to wet ones, was demonstrated interms of metamorphoses. However, anhydrobiosis did not protect against radiation damage in terms of producing viable offspring. These results indicate that anhydrobiosis enhances radiotolerance, resulting in increases of successful metamorphoses.

Journal Articles

Swift heavy ion irradiation effects in nanocrystalline gold

Chimi, Yasuhiro; Iwase, Akihiro*; Ishikawa, Norito; Kobiyama, Mamoru*; Inami, Takashi*; Kambara, Tadashi*; Okuda, Shigeo*

Nuclear Instruments and Methods in Physics Research B, 245(1), p.171 - 175, 2006/04

 Times Cited Count:15 Percentile:72.54(Instruments & Instrumentation)

We have studied effects of irradiation with energetic particles on defect accumulation in nanocrystalline gold (nano-Au). The specimens of nano-Au foil (3-5 $$mu$$m thickness) with various grain sizes (23-156 nm) are prepared by the gas deposition method and subsequent thermal annealings. Irradiations of the specimens with 60-MeV $$^{12}$$C ions, 3.54-GeV $$^{136}$$Xe ions or 2.0-MeV electrons are performed at low temperature. The defect accumulation behavior is observed by measuring the electrical resistivity change during irradiation. Through an analysis of defect accumulation behavior, cross-sections for defect production, $$sigma$$$$_{d}$$, and annihilation, $$sigma$$$$_{r}$$, in nano-Au increase monotonically as the grain size decreases. These results are considered to be caused by the existence of a large volume fraction of the regions near grain boundaries in nano-Au where the threshold energy for atomic displacements, E$$_{d}$$, becomes lower than in polycrystalline gold. The possibility of electronic excitation effects in nano-Au is also discussed.

Journal Articles

Magnetohydrodynamic stability of improved confinement plasmas in JT-60U

Takeji, Satoru; Isayama, Akihiko; Ozeki, Takahisa; Tokuda, Shinji; Ishii, Yasutomo; Oikawa, Toshihiro; Ishida, Shinichi; Kamada, Yutaka; Neyatani, Yuzuru; Yoshino, Ryuji; et al.

Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.278 - 297, 2002/09

 Times Cited Count:7 Percentile:9.09(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Observation of resistive wall modes in JT-60U

Takeji, Satoru; Tokuda, Shinji; Kurita, Genichi; Suzuki, Takahiro; Isayama, Akihiko; Takechi, Manabu; Oyama, Naoyuki; Fujita, Takaaki; Ide, Shunsuke; Ishida, Shinichi; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 78(5), p.447 - 454, 2002/05

no abstracts in English

Journal Articles

Accumulation and recovery of defects in ion-irradiated nanocrystalline gold

Chimi, Yasuhiro; Iwase, Akihiro; Ishikawa, Norito; Kobiyama, Mamoru*; Inami, Takashi*; Okuda, S.*

Journal of Nuclear Materials, 297(3), p.355 - 357, 2001/09

 Times Cited Count:198 Percentile:98.84(Materials Science, Multidisciplinary)

no abstracts in English

Oral presentation

Radiation tolerance in water bears

Horikawa, Daiki*; Sakashita, Tetsuya; Katagiri, Chihiro*; Watanabe, Masahiko*; Nakahara, Yuichi*; Okuda, Takashi*; Hamada, Nobuyuki*; Wada, Seiichi*; Funayama, Tomoo; Kobayashi, Yasuhiko

no journal, , 

no abstracts in English

34 (Records 1-20 displayed on this page)