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Segmental motions of proteins under non-native states evaluated using quasielastic neutron scattering

藤原 悟*; 松尾 龍人*; 杉本 泰伸*; 柴田 薫

Journal of Physical Chemistry Letters (Internet), 10(23), p.7505 - 7509, 2019/12

 被引用回数:0 パーセンタイル:0.01(Chemistry, Physical)

無秩序なポリペプチド鎖のダイナミクスの特性評価は、本質的に無秩序状態なタンパク質およびフォールディングプロセスに関連する非ネイティブ状態下のタンパク質の挙動を解明するために必要である。本研究では、小角X線散乱測定データと動的光散乱測定データと組み合わせて準弾性中性子散乱測定データから、タンパク質のセグメント運動と分子全体の拡散および局所側鎖運動を評価する方法を独自に開発した。そしてこの方法を、非フォールディング状態およびメルトグロビュール(MG)状態のタンパク質RNase Aに適用し、セグメント運動から生じる拡散係数を評価し、非フォールディング状態とMG状態で異なる値をとることを明らかにした。またこの方法で得られた値は、蛍光現象を用いた別の測定技術を使用して得られた値と一致していることも確認できた。これらの研究成果は、この方法の、さまざまな無秩序状態でのタンパク質の挙動を特徴付ける実行可能性だけでなく、有用性も示している。


Dynamic properties of human $$alpha$$-synuclein related to propensity to amyloid fibril formation

藤原 悟*; 河野 史明*; 松尾 龍人*; 杉本 泰伸*; 松本 友治*; 成田 哲博*; 柴田 薫

Journal of Molecular Biology, 431(17), p.3229 - 3245, 2019/08

 被引用回数:3 パーセンタイル:27.91(Biochemistry & Molecular Biology)



Measurement of neutron scattering cross section of nano-diamond with particle diameter of approximately 5 nm in energy range of 0.2 meV to 100 meV

勅使河原 誠; 土川 雄介*; 市川 豪*; 高田 慎一; 三島 賢二*; 原田 正英; 大井 元貴; 河村 幸彦*; 甲斐 哲也; 河村 聖子; et al.

Nuclear Instruments and Methods in Physics Research A, 929, p.113 - 120, 2019/06

 被引用回数:7 パーセンタイル:75.46(Instruments & Instrumentation)

ナノダイアモンドは、冷中性子以下のエネルギーにおける反射材として注目されている。ナノダイアモンドを用いた中性子源の高度化には、断面積データの整備が必要である。そのため、この論文では、中性子の透過率の測定から0.2meVから100meVの範囲で全断面積を測定した結果を報告する。測定した全断面積は、エネルギーが低くなるにつれて大きくなり、グラファイトと比較すると0.2meVで約2桁以上高くなることが分かった。その全断面積に占める非弾性散乱の寄与を調べるため、中性子のエネルギー1.2, 1.5, 1.9及び5.9meVで中性子非弾性散乱実験を行った。その結果、測定したエネルギーにおいて、全断面積に占める非弾性散乱の寄与がほぼ無視できることも分かった。さらに、中性子小角散乱実験の結果から、全断面積の高くなる要因として、前方方向、いわゆる小角方向への散乱の寄与が高いことが示された。


Energy-resolved small-angle neutron scattering from steel

大場 洋次郎*; 諸岡 聡; 大石 一城*; 鈴木 淳市*; 高田 慎一; 佐藤 信浩*; 井上 倫太郎*; 土山 聡宏*; Gilbert, E. P.*; 杉山 正明*

Journal of Applied Crystallography, 50(2), p.334 - 339, 2017/04

 被引用回数:2 パーセンタイル:26.99(Chemistry, Multidisciplinary)

Recent progress of pulsed neutron sources has enabled energy-resolved analysis of neutron attenuation spectra, which include information on neutron scattering. In this study, a new analysis technique for small-angle neutron scattering (SANS) is demonstrated. A clear difference is observed in the neutron attenuation spectra between steels with different nanostructures; this difference can be understood as arising from attenuation due to SANS. The neutron attenuation spectra, calculated from the corresponding SANS profiles, agree well with the experimentally observed attenuation spectra. This result indicates that measurement of neutron attenuation spectra may enable the development of a novel experimental technique, i.e. energy-resolved SANS (ESANS).


Effect of thermo-mechanical treatments on nano-structure of 9Cr-ODS steel

岡 弘; 丹野 敬嗣; 大塚 智史; 矢野 康英; 上羽 智之; 皆藤 威二; 大沼 正人*

Nuclear Materials and Energy (Internet), 9, p.346 - 352, 2016/12

 被引用回数:14 パーセンタイル:86.01(Nuclear Science & Technology)

The effect of thermo-mechanical treatments (TMTs) on the evolution of nano-structure in an oxide dispersion strengthened (ODS) ferritic/martensitic steel (Fe-9Cr-2W-0.22Ti-0.36Y$$_{2}$$O$$_{3}$$) was investigated. TMTs involve hot extruding and subsequent forging, which are expected to be part of a future industrial-scale manufacturing process of the ODS steel. It was shown that the ODS steel was composed of two phases - a fine-grained residual ferrite phase and a transformable martensite phase. The number density of the nano-sized particles in the residual ferrite phase was significantly higher than that in the martensite phase. The TMTs did not significantly affect the number density, but slightly affected the size distribution of the nano-sized particles in both ferrite phase and martensite phase. Moreover, the volume fraction of the residual ferrite phase decreased after TMTs. In summary, the TMT conditions could be a parameter which affects the nano-structure of the ODS steel.



大場 洋次郎*; 諸岡 聡; 佐藤 博隆*; 佐藤 信浩*; 井上 倫太郎*; 杉山 正明*

波紋, 26(4), p.170 - 173, 2016/11

Based on the time-of-light (TOF) technique, new generation pulsed neutron sources enable novel neutron scattering experiments. Using small-angle neutron scattering (SANS) at the pulsed neutron sources, simultaneous measurements of SANS and Bragg edge transmission can be performed. From the SANS profiles, the precipitates and inclusions in metals and alloys are characterized, while the Bragg edge transmission spectra give crystallographic information about the matrix. This is a powerful tool for quantitative characterization of the microstructures in the metals and alloys. The neutron transmission experiments have potential for further development. Magnetic Bragg edge transmission analysis will be useful for magnetic materials. These new neutron scattering techniques enhance the usability and flexibility of neutron scattering experiments.


Magnetic scattering in the simultaneous measurement of small-angle neutron scattering and Bragg edge transmission from steel

大場 洋次郎*; 諸岡 聡; 大石 一城*; 佐藤 信浩*; 井上 倫太郎*; 足立 望*; 鈴木 淳市*; 土山 聡宏*; Gilbert, E. P.*; 杉山 正明*

Journal of Applied Crystallography, 49(5), p.1659 - 1664, 2016/10

 被引用回数:9 パーセンタイル:63.8(Chemistry, Multidisciplinary)

Pulsed neutron sources enable the simultaneous measurement of small-angle neutron scattering (SANS) and Bragg edge transmission. This simultaneous measurement is useful for microstructural characterization in steel. Since most steels are ferromagnetic, magnetic scattering contributions should be considered in both SANS and Bragg edge transmission analyses. An expression for the magnetic scattering contribution to Bragg edge transmission analysis has been derived. The analysis using this expression was applied to Cu steel. The ferrite crystallite size estimated from this Bragg edge transmission analysis with the magnetic scattering contribution was larger than that estimated using conventional expressions. This result indicates that magnetic scattering has to be taken into account for quantitative Bragg edge transmission analysis. In the SANS analysis, the ratio of magnetic to nuclear scattering contributions revealed that the precipitates consist of body-centered cubic Cu$$_{0.7}$$Fe$$_{0.3}$$ and pure Cu, which probably has 9R structure including elastic strain and vacancies. These results show that effective use of the magnetic scattering contribution allows detailed analyses of steel microstructure.


Elucidation of the morphology of the hydrocarbon multi-block copolymer electrolyte membranes for proton exchange fuel cells

Zhao, Y.; 吉田 実留*; 大島 竜也*; 小泉 智*; 陸川 政弘*; Szekely, N.*; Radulescu, A.*; Richter, D.*

Polymer, 86, p.157 - 167, 2016/03

 被引用回数:12 パーセンタイル:53.39(Polymer Science)

We investigated the structure and the swelling behavior of two synthesized hydrocarbon polymer electrolyte membranes, made of multiblock copolymer poly(sulphonate phenylene)-b-poly(arylene ether ketone) with different block ratios, by using small-angle neutron scattering technique. A scattering maximum (ionomer peak) at high-q range is shown commonly in both dry and wet states, with q being the magnitude of the scattering vector, while it shifts towards low-q region in the wet state due to the swelling of the ionomer domains with water. The swelling effect also results to a second scattering maximum in the middle-q range because of the water-induced microphase separation. The morphology in this q-range was elucidated in terms of Hard-Sphere model with Percus-Yervick interference approximation.


Imidazolium-based anion exchange membranes for alkaline anion fuel cells; Elucidation of the morphology and the interplay between the morphology and properties

Zhao, Y.; 吉村 公男; 猪谷 秀幸*; 山口 進*; 田中 裕久*; 小泉 智*; Szekely, N.*; Radulescu, A.*; Richter, D.*; 前川 康成

Soft Matter, 12(5), p.1567 - 1578, 2016/02

 被引用回数:23 パーセンタイル:82.25(Chemistry, Physical)

We investigated the interplay between morphology and properties of a new graft-type of anion exchange membranes (AEMs) containing 2-methylimidazolium groups by using contrast variation small angle neutron scattering (SANS) technique. These AEMs prepared by radiation-induced grafting of 2-methyl-1-vinylimidazole and styrene into poly(ethylene-co-tetrafluoroethylene) (ETFE) films, possessed both high alkaline durability and high conductivity. The SANS measurement reveals that these membranes are consisted of three phases: crystalline lamellar and crystallite domains originating from the pristine ETFE, which offer good mechanical properties, hydrophobic amorphous domains, which offer a matrix to create conducting regions, and interconnected hydrated domains, which are composed of the entire graft chains and water and play a key role to promote the conductivity.


A Crafty utilization of intermediate-angle neutron scattering and contrast variation by water-exchange to study the microstructure of microbial cellulose

Zhao, Y.; 小泉 智*; 近藤 哲男*

JPS Conference Proceedings (Internet), 8, p.033002_1 - 033002_6, 2015/09

Incoherent neutron scattering contribution presents a challenge in the structure characterization of many target materials. In this study, we introduce a method of intermediate angle neutron scattering (IANS) to correct the small angle neutron scattering (SANS) data of the water-swollen microbial cellulose (MC) sample, the system of which has significant incoherent contributions from the water solvent, and we describe the effects that the corrections have on the structural analysis. In order to elucidate the structure, the solvent is changed in situ from protonated water to deuterated water to give different scattering contrast, and this water-exchange process has been followed by time-resolved SANS and IANS simultaneously. Our results show that: (1) after incoherent correction, the structure of MC sample is proved to be invariant with solvents; (2) the scattering intensity depends only on the contrast factor, revealing a two-phase system composed of water-resistant crystalline cellulose phase and hydrated phase; (3) The cellulose crystallites have a constant scattering length density of 2.0$$times$$10$$^{10}$$cm$$^{-2}$$, determined by the matching point at which the scattering contrast between the two phases is minimum. This value is consistent with that of 1.9$$times$$10$$^{10}$$cm$$^{-2}$$ estimated from its chemical structure.


Small angle scattering from neutron irradiated amorphous Pd$$_{8}$$$$_{0}$$ Si$$_{2}$$$$_{0}$$

土井 健治; 茅野 秀夫*; 増本 健*

Journal of Applied Crystallography, 11(5), P. 605, 1978/00


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