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Kubota, Tomohiro; Kuroda, Hisao*; Watanabe, Mirai*; Takahashi, Akiko*; Nakazato, Ryoji*; Tarui, Mika*; Matsumoto, Shunichi*; Nakagawa, Keita*; Numata, Yasuko*; Ouchi, Takao*; et al.
Atmospheric Environment, 243, p.117856_1 - 117856_9, 2020/12
Times Cited Count：3 Percentile：15.82(Environmental Sciences)The dry and wet depositions of atmospheric ammonia (NH
) is one of the important pathways of nitrogen loads to aquatic ecosystems. Crop and livestock agriculture, one of the largest emitters of NH in Asian countries, are known to cause high spatial and seasonal variation of NH and influence the surrounding lake basin areas via its dry and wet deposition. However, the spatial characteristics of the NH concentration in basin scale are not completely understood for regulation in NH emission. Here we aim to clarify dominant factors of spatial and seasonal variations of the NH concentration in a eutrophic lake basin surrounded by agricultural areas in Japan. Passive sampling over various land use categories in the basin was conducted at 36 sites in total from October 2018 to January 2020. Interestingly, the observed NH concentration near the livestock houses were higher in winter than summer, which was inconsistent with knowledge of seasonal changes of current NH emission inventory based on temperature-driven volatilization process. Comparing monthly NH concentrations with various meteorological factors, we suggested the importance of seasonal advection of NH from high emission sources to which has been rarely paid attention by the previous past studies. As for this, should be considered for lake ecosystem management since deposition of NH is known to be closely related to the ecological processes such as phytoplankton blooming.
Yamada, Susumu; Igarashi, Ryo; Okumura, Masahiko*; Imamura, Toshiyuki*; Machida, Masahiko
Oyo Suri, 20(2), p.132 - 147, 2010/06
The density matrix renormalization group (DMRG) method is a numerical calculation technique to obtain the ground state of quantum lattice systems whose degree of freedoms exponentially grows with the size of the lattice sites and particles (or spins in interacting spin systems). Its advantage is excellent accuracy comparable to the exact diagonalization scheme even in considerably large number of sites and particles (spins). However, the technique has been originally developed for one-dimensional systems. Therefore, the extension to higher dimensional lattices systems is in great demand since major rich physics such as superconductivity and ferromagnetism frequently occurs in two or three dimensions. This paper describes a parallelization strategy of the technique to calculate quasi-two dimensional (ladder) systems toward the next generation supercomputer and reports its good parallel efficiency on T2K supercomputer HA8000 at University of Tokyo. Moreover, typical quantum phenomena obtained by using the parallelized code are exhibited and some remarks on parallelization scheme in the next generation supercomputer are mentioned.
raysHashimoto, Makoto; Otaka, Masahiko; Ara, Kuniaki; Kanno, Ikuo; Imamura, Ryo*; Mikami, Kenta*; Nomiya, Seiichiro*; Onabe, Hideaki*
Journal of Nuclear Science and Technology, 46(1), p.76 - 82, 2009/01
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)A photon detector for unfolding X-ray energy distribution has been previously reported. Simulation studies on the unfolding method for this detector are discussed for diagnostic X-rays and mixed-source rays of 
Cs/
Co. Response functions for diverse diagnostic X-rays are almost indistinguishable and an unfolding using error reduction method is not sufficiently worked. The spectrum surveillance method is effective in this case. However, a simple error reduction method is useful for mixed rays. For both techniques, the neural network method is promising.
Onishi, Ryoichi*; Guo, Z.*; Imamura, Toshiyuki; Hirayama, Toshio
GMD Report 132, 1 Pages, 2001/04
no abstracts in English
Yamada, Susumu; Imamura, Toshiyuki*; Okumura, Masahiko; Igarashi, Ryo; Machida, Masahiko
no journal, ,
no abstracts in English
Yamada, Susumu; Imamura, Toshiyuki*; Okumura, Masahiko; Igarashi, Ryo; Machida, Masahiko
no journal, ,
no abstracts in English
Yamada, Susumu; Imamura, Toshiyuki*; Okumura, Masahiko; Igarashi, Ryo; Machida, Masahiko
no journal, ,
no abstracts in English
Yamada, Susumu; Imamura, Toshiyuki*; Okumura, Masahiko*; Igarashi, Ryo; Onishi, Hiroaki; Machida, Masahiko
no journal, ,
no abstracts in English
Yamada, Susumu; Imamura, Toshiyuki*; Okumura, Masahiko; Igarashi, Ryo; Yamamoto, Atsushi; Machida, Masahiko
no journal, ,
no abstracts in English
-Lactamase TOHO-1 determined by combined high-resolution neutron and X-ray crystallographyKurihara, Kazuo; Sunami, Tomoko; Yamada, Mitsugu; Nitanai, Yasushi*; Okazaki, Nobuo; Adachi, Motoyasu; Tamada, Taro; Shimamura, Tatsuro*; Miyano, Masashi*; Ishii, Yoshikazu*; et al.
no journal, ,
To help resolve questions regarding the catalytic activity of -lactamase, the crystal structure of an unliganded form of the -lactamase Toho-1 with double mutation R274N/R276N (Toho-1/NN) has been determined by the use of high-resolution neutron and X-ray diffraction data. A large single crystal of Toho-1/NN with a dimension of 2.6 
2.5 1.3 mm
was used to collect 100 K neutron diffraction data to 1.5 
resolution and X-ray diffraction data to 1.4 resolution. The structural model of Toho-1/NN was refined to an R-factor of 19.7% using a program PHENIX. The structure showed that Glu166, a catalytic residue of Toho-1, was protonated even at pH 7 nonetheless for the close location to the positively charged side chain amino group (-NH3
) of Lys73. It is also found that there is a hydration water network bridging between the protonated Glu166 and the oxyanion hole comprising two main chain nitrogen atoms of Ser70 and Ser237. The neutron structure analysis also revealed the clear configuration of the proposed catalytic water molecule bridging Glu166 and Ser70. These observations are important to understand the catalytic action of -lactamase Toho-1.
Katata, Genki*; Kubota, Tomohiro; Kuroda, Hisao*; Watanabe, Mirai*; Takahashi, Akiko*; Nakazato, Ryoji*; Tarui, Mika*; Matsumoto, Shunichi*; Nakagawa, Keita*; Numata, Yasuko*; et al.
no journal, ,
no abstracts in English
