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Journal Articles

Simultaneous determination of zircon crystallisation age and temperature; Common thermal evolution of mafic magmatic enclaves and host granites in the Kurobegawa granite, central Japan

Yuguchi, Takashi*; Yamazaki, Hayato*; Ishibashi, Kozue*; Sakata, Shuhei*; Yokoyama, Tatsunori; Suzuki, Satoshi*; Ogita, Yasuhiro; Sando, Kazusa*; Imura, Takumi*; Ono, Takeshi*

Journal of Asian Earth Sciences, 226, p.105075_1 - 105075_9, 2022/04

https://doi.org/10.1016/j.jseaes.2021.105075

Simultaneous determination of the U-Pb age of zircon and concentration of titanium in a single analysis spot, using inductively coupled plasma mass spectrometry with laser ablation sample introduction, produces paired age and temperature data of zircon crystallisation, potentially revealing time-temperature () histories for evolved magma. The Kurobegawa granite, central Japan, contains abundant mafic magmatic enclaves (MMEs). We applied this method to evaluate MMEs and their host (enclosing) granites. Cooling behaviour common to both MMEs and host rocks was found between 1.5 and 0.5 Ma. Rapid cooling from the zircon crystallisation temperature to the closure temperature of biotite K-Ar system was within 1 million year. Combining the obtained paths of MMEs and host rocks with petrological information can provide insights into magma chamber processes. This suggests that MME flotation, migration, and spread through the magma chamber ceased at 1.5-0.5 Ma, indicating the emplacement age of the Kurobegawa granitic pluton, as no large-scale reheating episodes have occurred since then.

Journal Articles

Phase-field model for crystallization in alkali disilicate glasses; LiO-2SiO, NaO-2SiO and KO-2SiO

Kawaguchi, Munemichi; Uno, Masayoshi*

Journal of the Ceramic Society of Japan, 128(10), p.832 - 838, 2020/10

https://doi.org/10.2109/jcersj2.20145

Times Cited Count：0 Percentile：0.01(Materials Science, Ceramics)

This study developed phase-field method (PFM) technique in oxide melt system by using a new mobility coefficient (). The crystal growth rates () obtained by the PFM calculation with the constant were comparable to the thermodynamic driving force in normal growth model. The temperature dependence of the was determined from the experimental crystal growth rates and the . Using the determined , the crystal growth rates () in alkali disilicate glasses, LiO-2SiO, NaO-2SiO and KO-2SiO were simulated. The temperature dependence of the was qualitatively and quantitatively so similar that the PFM calculation results demonstrated the validity of the . Especially, the obtained by the PFM calculation appeared the rapid increase just below the thermodynamic melting point ( $T_{rm m}$ ) and the steep peak at around $T_{rm m}$ -100 K. Additionally, as the temperature decreased, the apparently approached zero ms, which is limited by the representing the interface jump process. Furthermore, we implemented the PFM calculation for the variation of the parameter in the . As the increased from zero to two, the peak of the became steeper and the peak temperature of the shifted to the high temperature side. The parameters and in the increased exponentially and decreased linearly as the atomic number of the alkali metal increased due to the ionic potential, respectively. This calculation revealed that the and in the were close and reasonable for each other.

Journal Articles

Purification of uranium products in crystallization system for nuclear fuel reprocessing

Takeuchi, Masayuki; Yano, Kimihiko; Shibata, Atsuhiro; Sambommatsu, Yuji*; Nakamura, Kazuhito*; Chikazawa, Takahiro*; Hirasawa, Izumi*

Journal of Nuclear Science and Technology, 53(4), p.521 - 528, 2016/04

https://doi.org/10.1080/00223131.2015.1060907

Times Cited Count：2 Percentile：25.63(Nuclear Science & Technology)

Journal Articles

Recent results on hydrogen and hydration in biology studied by neutron macromolecular crystallography

Niimura, Nobuo; Arai, Shigeki; Kurihara, Kazuo; Chatake, Toshiyuki*; Tanaka, Ichiro*; Bau, R.*

Cellular and Molecular Life Sciences, 63(3), p.285 - 300, 2006/02

https://doi.org/10.1007/s00018-005-5418-3

Times Cited Count：40 Percentile：39.2(Biochemistry & Molecular Biology)

Neutron diffraction provides an experimental method of directly locating hydrogen atoms in proteins and DNA oligomers. Three different types of high resolution neutron diffractometers for biological macromolecules have been constructed in Japan, France and the U.S.A., and they have all been actively used in recent years to determine the crystal structures of numerous proteins. Examples include the detailed geometries of hydrogen bonds, information on H/D exchange in proteins, the unambiguous location of protons, the role of key hydrogen atoms in enzymatic activity and thermostability, and the dynamical behavior of hydration structures, all of which have been extracted from these structural results and reviewed in this article. Other important techniques, such as the optimization of growth of large single crystals using phase diagrams, the preparation of fully deuterated proteins, the introduction of cryogenic techniques to neutron protein crystallography, and the establishment of a "hydrogen and hydration in proteins" database, will also be described in this paper.

Journal Articles

Crystallization of a 2:2 complex of Granulocyte-Colony Stimulating Factor (GCSF) with the ligand-binding region of the GCSF receptor

Honjo, Eijiro; Tamada, Taro; Maeda, Yoshitake*; Koshiba, Takumi*; Matsukura, Yasuko*; Okamoto, Tomoyuki*; Ishibashi, Matsujiro*; Tokunaga, Masao*; Kuroki, Ryota

Acta Crystallographica Section F, 61(8), p.788 - 790, 2005/08

https://doi.org/10.1107/S1744309105023080

Times Cited Count：7 Percentile：56.84(Biochemical Research Methods)

Granulocyte colony-stimulating factor (GCSF) receptor receives signals for regulating the proliferation and differentiation of the precursor cells of granulocytes. The complex composed of two GCSFs and two GCSF receptors was crystallized. The crystal of the complex was grown in 1.0 M sodium formate and 0.1 M sodium acetate (pH4.6). It belongs to the space group 4 $_{1}$ 2 $_{1}$ 2 (or its enantiomorph 4 $_{3}$ 2 $_{1}$ 2) with unit cell dimensions of = = 110.1 , = 331.8 . However, the diffraction data from the crystal beyond 5 resolution could not be collected. Since the heterogeneity of GCSF receptor seems to interrupt growth of good quality crystals, the GCSF receptor was fractionated by achromatography. Crystals of GCSF/fractionated GCSF receptor complex were grown as a new crystal form in 0.2 M ammonium phosphate. The new crystal diffracts beyond 3.0 resolution and belongs to space group 3 $_{1}$ 21 (or its enantiomorph 3 $_{2}$ 21) with unit-cell parameters = = 134.8, = 105.7 .

Journal Articles

Hydrogen and hydration in proteins and nucleic acids; Neutron diffraction from bio-macromolecules at JAERI

Niimura, Nobuo; Arai, Shigeki; Kurihara, Kazuo; Chatake, Toshiyuki*; Tanaka, Ichiro*; Bau, R.*

Hydrogen- and Hydration-Sensitive Structural Biology, p.17 - 35, 2005/00

At the JAERI, we have constructed several high-resolution neutron diffractometers dedicated to biological macromolecules (called BIX-type diffractometers), which use a monochromatized neutron beam and a neutron imaging plate detector. In this paper, we review several interesting results regarding hydrogen positions and hydration in proteins, obtained using the two BIX-type diffractometers in JAERI. The general subject of neutron protein crystallography has been reviewed by several authors, and several selected topics have been discussed.

Journal Articles

Spatial pattern formation in asynchronous cellular automata with mass conservation

Suzudo, Tomoaki

Physica A, 343, p.185 - 200, 2004/11

https://doi.org/10.1016/S0378-4371(04)00857-X

Times Cited Count：22

This paper proposes a class of 2-dimensional asynchronous cellular automata with conservation of mass, for the formation of patterns in groups, and describes the merits given by this methodology. A cellular automaton rule causing a specified kind of pattern was designed manually. Thanks to this realistic modeling method reflecting nature, the mechanism of pattern formation was found to be similar to real chemical processes. A search technique using genetic algorithm is applied to find pattern-forming CAs, and it successfully find a few types of spontaneous pattern formations. This technique is expected to be applied to a wide range of potential studies related to self-organization.

Journal Articles

Neutron diffractometer for biological macromolecule crystallography

Kurihara, Kazuo; Tanaka, Ichiro*; Niimura, Nobuo

Nihon Kessho Gakkai-Shi, 46(3), p.193 - 200, 2004/05

https://doi.org/10.5940/jcrsj.46.193

Neutron diffraction provides an experimental method of directly locating hydrogen atoms in proteins and nucleic acids, and the development of the neutron imaging plate (NIP) became a breakthrough event in neutron protein crystallography. A high-resolution neutron diffractometers dedicated to biological macromolecules (BIX-3, BIX-4) with the NIP have been constructed at Japan Atomic Energy Research Institute. The detailed structure of the diffractometer and the systematic procedure of the neutron diffraction experiment from the crystallization of a large single crystal to the data collection and the data processing, and the future prospect of the neutron diffractometry in proteins will be presented.

Journal Articles

Preparation of TiO $_{2}$ nanoparticles by pulsed laser ablation; Ambient pressure dependence of crystallization

Matsubara, Masakazu*; Yamaki, Tetsuya; Ito, Hisayoshi; Abe, Hiroaki*; Asai, Keisuke*

Japanese Journal of Applied Physics, Part 2, 42(5A), p.L479 - L481, 2003/05

Pulsed laser ablation with a KrF excimer laser was used to prepare fine particles of titanium dioxide (TiO $_{2}$ ). The ablation in an atmosphere of Ar and O $_{2}$ (5:5) at total pressures of 1 Torr led to the formation of TiO $_{2}$ nanoparticles composed of anatase and rutile structures without any suboxides. The weight fraction of the rutile/anatase crystalline phases was controlled by the pressure of the Ar/O $_{2}$ gas. The TiO $_{2}$ nanoparticles had a spherical shape and their size, ranging from 10 and 14 nm, also appeared to be dependent on the ambient pressure.