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Miyazawa, Yutaka*; Sakashita, Tetsuya; Funayama, Tomoo; Hamada, Nobuyuki*; Negishi, Hiroshi*; Kobayashi, Akie*; Kaneyasu, Tomoko*; Oba, Atsushi*; Morohashi, Keita*; Kakizaki, Takehiko*; et al.
Journal of Radiation Research, 49(4), p.373 - 379, 2008/07
Times Cited Count：28 Percentile：62.78(Biology)We examined the role of root cap and elongation zone cells in root hydrotropism using heavy-ion and laser microbeam. Heavy-ion microbeam irradiation of the elongation zone, but not that of the columella cells, significantly and temporary suppressed the development of hydrotropic curvature. However, laser ablation confirmed that columella cells are indispensable for hydrotropism. Systemic heavy-ion broad-beam irradiation suppressed 
expression of 
gene, but not 
gene. Our results indicate that both the root cap and elongation zone have indispensable and functionally distinct roles in root hydrotropism, and that gene expression might be required for hydrotropism in the elongation zone, but not in columella cells.
using heavy-ion microbeamMiyazawa, Yutaka*; Sakashita, Tetsuya; Negishi, Hiroshi*; Kobayashi, Akie*; Kaneyasu, Tomoko*; Oba, Atsushi*; Morohashi, Keita*; Kakizaki, Takehiko*; Funayama, Tomoo; Hamada, Nobuyuki*; et al.
JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 116, 2008/03
We examined the role of root cap and elongation zone cells in root hydrotropism of using heavy ion and laser microbeam. Heavy ion microbeam irradiation of the elongation zone, but not that of the columella cells, significantly and temporarily suppressed the development of hydrotropic curvature. However, laser ablation confirmed that columella cells are indispensable for hydrotropism. Systemic heavy ion broad beam irradiation suppressed de novo expression of INDOLE ACETIC ACID 5 gene. Our results indicate that both the root cap and elongation zone have indispensable and functionally distinct roles in root hydrotropism, and that de novo gene expression might be required for hydrotropism in the elongation zone, but not in columella cells.
Okubo, Tsutomu; Uchikawa, Sadao; Nakano, Yoshihiro; Akie, Hiroshi; Kobayashi, Noboru; Fukaya, Yuji
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM), 7 Pages, 2007/04
For the future sustainable energy supply based on the matured LWR technologies, a concept of FLWR has been studied in JAEA. The concept utilizes the tight-lattice core loaded with the MOX fuel, and consists of two steps. The first step realizes a high conversion type one (HC-FLWR) to keep the smooth technical continuity from the LWR technologies. The second is the RMWR concept, which realizes a high conversion ratio over 1.0 for Pu multiple recycling. The key point is that the two core concepts utilize the same size fuel assemblies, and hence, the former can proceed to the latter in the same reactor system based flexibly on the future fuel cycle circumstances. In the present paper, investigation results on the FLWR conceptual design are presented. The design of the HC-FLWR core has been recently improved, and detailed core properties have been evaluated by the neutronics and thermal-hydraulics coupled calculations. The core can achieve the average burn-up around 55GWd/t.
Miyazawa, Yutaka*; Negishi, Hiroshi*; Sakashita, Tetsuya; Kobayashi, Akie*; Kaneyasu, Tomoko*; Oba, Atsushi*; Funayama, Tomoo; Wada, Seiichi*; Hamada, Nobuyuki*; Kakizaki, Takehiko; et al.
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 119, 2007/02
Yonomoto, Taisuke; Akie, Hiroshi; Kobayashi, Noboru; Okubo, Tsutomu; Uchikawa, Sadao; Iwamura, Takamichi
Proceedings of 6th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operations and Safety (NUTHOS-6) (CD-ROM), 11 Pages, 2004/10
Reduced-Moderation Water Reactor (RMWR) is a light-water cooled high-conversion reactor that is being developed by JAERI with collaboration from the Japanese industries. Since RMWR utilizes the highly enriched plutonium, the safety concern for RMWR includes the possibility of recriticality during severe accidents as is the case with the liquid metal cooled fast breeder reactor. In order to clarify this concern, characteristics of severe accidents of RMWR are analyzed in this study. The results obtained so far indicate that (1) the mechanical impact of recriticality in the core, if occurs, is supposed to be insignificant due to the absence of water, (2) the mixture of the fuel and cladding debris in the lower plenum does not cause recriticality when they are well mixed and distributed flatly, and (3) if requires, the installation of neutron-absorption material with realistic geometry can effectively prevent recriticality in the lower plenum even for the conservatively-assumed spherical accumulation of core debris.
Negishi, Hiroshi*; Miyazawa, Yutaka*; Sakashita, Tetsuya; Kobayashi, Akie*; Kaneyasu, Tomoko*; Oba, Atsushi*; Funayama, Tomoo; Wada, Seiichi; Hamada, Nobuyuki; Kakizaki, Takehiko; et al.
no journal, ,
no abstracts in English
Negishi, Hiroshi*; Miyazawa, Yutaka*; Sakashita, Tetsuya; Kobayashi, Akie*; Kaneyasu, Tomoko*; Oba, Atsushi*; Funayama, Tomoo; Wada, Seiichi; Hamada, Nobuyuki; Kakizaki, Takehiko; et al.
no journal, ,
no abstracts in English
Miyazawa, Yutaka*; Negishi, Hiroshi*; Kobayashi, Akie*; Kaneyasu, Tomoko*; Oba, Atsushi*; Fujii, Nobuharu*; Takahashi, Hideyuki*; Sakashita, Tetsuya; Funayama, Tomoo; Wada, Seiichi*; et al.
no journal, ,
no abstracts in English
Miyazawa, Yutaka*; Sakashita, Tetsuya; Negishi, Hiroshi*; Kobayashi, Akie*; Oba, Atsushi*; Kaneyasu, Tomoko*; Morohashi, Keita*; Takahashi, Akiko*; Kakizaki, Takehiko*; Funayama, Tomoo; et al.
no journal, ,
We examined the function of root cap and elongation zone cells in root hydrotropism by nondestructive cell inactivation using heavy-ion microbeam irradiation. Systemic heavy-ion irradiation inactivated de novo indole acetic acid 5 gene expression. Local irradiation of the elongation zone significantly suppressed the development of hydrotropic curvature, whereas local irradiation of the columella cells did not. However, laser ablation confirmed that columella cells are indispensable for hydrotropism. Our results indicate that both the root cap and elongation zone have indispensable and functionally distinct roles in root hydrotropism, and that in the elongation zone, de novo gene expressions, including auxin-responsible gene expression, is required for hydrotropism, whereas in columella cells, it is not.
