Updated on 2026/04/03

写真a

 
OKAMOTO Ryuuichi
 
Organization
Scheduled update Associate Professor
Position
Associate Professor
External link

Degree

  • 博士(理学) ( 2007.3   慶應義塾大学 )

  • Ph.D in science ( 2007.3   Keio University )

Research Interests

  • Phase transition

  • solvation effect

  • Soft matter

  • electrolyte

  • chemical physics

  • critical phenomena

Research Areas

  • Natural Science / Biophysics, chemical physics and soft matter physics

Education

  • Keio University   理工学研究科   基礎理工学専攻

    2004.4 - 2007.3

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    Country： Japan

    Notes： 後期博士課程

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  • Keio University   基礎理工学専攻  

    2002.4 - 2004.3

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    Country： Japan

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  • Keio University   理工学部   物理情報工学科

    1998.4 - 2002.3

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    Country： Japan

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Research History

  • Okayama University   The Research Institute for Interdisciplinary Science   Associate Professor

    2026.4

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  • 兵庫県立大学 大学院情報科学研究科

    2024.4

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  • University of Hyogo   大学院情報科学研究科

    2022.8

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  • Okayama University   Research institute for interdisciplinary science   Lecturer

    2017.8 - 2022.7

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    Country：Japan

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Professional Memberships

 

Papers

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MISC

Awards

  • 2017 Young Scientist Award of Physical Society of Japan

    2017.3   The Physical Society of Japan   Theoretical Finding of Novel Solvation Effects in Soft Matter

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Research Projects

  • Understanding solvent-mediated forces with diverse responses to ions, co-solvents, and temperature

    Grant number：18KK0151  2018.10 - 2023.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))  Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))

    甲賀 研一郎, 岡本 隆一, 墨 智成, 望月 建爾

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    Grant amount：\17940000 （ Direct expense: \13800000 、 Indirect expense：\4140000 ）

    （１）水溶液中の疎水性溶質の溶媒和自由エネルギーに対するイオン添加効果について予備的な分子動力学シミュレーション計算を進め，今後の研究方針を固めた．第一に，電荷をもったイオンの場合，既存の分子間相互作用ポテンシャルがイオン水溶液の基礎物性をうまく再現することができないという点を確認し，ポテンシャルを改良することを試みた．その結果，イオンの電荷qをそのまま用いるのではなく，分子分極を考慮するために，一定の割合でqを減少させることにより，総合的に基礎物性がうまく再現できることを確認した．今後，このイオンポテンシャルを用いて，疎水性分子の溶媒和エネルギーに対するイオンの添加効果をイオン種毎に明らかにし，その機構を解明する．
    （２）溶質溶解度に対するイオン添加効果を定量化するために用いられるセチェノフ係数を溶液構造を反映する相関関数積分によって与える式を導出した．この式を用いて，イオン種および溶質分子種に依存するセチェノフ係数の大小を溶液の微視的構造から理解することができる．
    （３）シニョリンとよばれる人工タンパク質の水溶液中における安定性の機構を液体の密度汎関数理論とシミュレーションを組み合わせた方法により，解明した．その結果，従来の定説とは反対に，溶媒誘起力はタンパク質の折り畳み構造を不安定化させる方向に寄与しており，タンパク質分子内直接相互作用が折り畳みにおける駆動力であることが定量的に示された．この結果は，疎水効果が折りたたみ構造を安定化させるという既存仮説を否定するが，一般的なタンパク質に関する熱測定や部位突然変異体導入に基づく結論と一致する．

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  • Theoretical study of steric effects in electrolyte solutions: Toward thorough understanding of Hofmester effect

    Grant number：18K03562  2018.04 - 2021.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Okamoto Ryuichi

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    Grant amount：\4160000 （ Direct expense: \3200000 、 Indirect expense：\960000 ）

    In dilute electrolyte solutions, there exist universal laws such as the Debye-Huckel law of the activity coefficient. As the ion concentration increases, ion-specificity becomes more noticeable; ion-specificity means ions with the same valence numbers have different effects on the properties of solutions. The two major achievements are as follows. (i) we showed that the ion-specificities in the ion activity coefficient, osmotic coefficient, and salt partial volume are explained as a result of combination of steric effects of the ions and the solvent and the electrostriction of ions. (ii) For solutions of hydrophobic molecules, we found a simple relationship between the ion effects on the solubility and the hydrophobic interaction. The latter is relevant to the conformation of macromolecules, e.g., DNAs, proteins in salt solutions.

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  • Theoretical study on the universal behaviors in cell rheology

    Grant number：15K05250  2015.04 - 2018.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)  Grant-in-Aid for Scientific Research (C)

    Komura Shigeyuki

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    Grant amount：\4420000 （ Direct expense: \3400000 、 Indirect expense：\1020000 ）

    With the development of the new experimental technique called microrheology, many knowledges concerning cell rheology have been accumulating all over the world in the last decade. In this research project, with the aim to understand the universal behaviors in cell rheology within soft matter physics and nonequilibrium physics, we have developed fundamental theories for microrheology that is applicable to inhomogeneous and nonequilibrium systems. Furthermore, we have established a new microrheology method that is suitable for investigating mechanical responses in cells coated with biomembranes. In particular, we have established the followings: (i) basic theory for membrane microrhelogy, (ii) active microrheology in multi-component media, and (iii) detection of non-thermal fluctuations by using microrhelogy methods.

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  • Study of selective solvation, ionization, and chemical reaction

    Grant number：25610122  2013.04 - 2016.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research  Grant-in-Aid for Challenging Exploratory Research

    Onuki Akira, Okamoto Ryuichi, Takae Kyouhei

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    Grant amount：\3900000 （ Direct expense: \3000000 、 Indirect expense：\900000 ）

    1)We constructed a theory of dielectric response in liquid water using large-scale molecular dynamics simulation. We also examined nonequilibrium relaxation
    after electric field reversal. 2) We presented a theory of nanobubbles when a small amount of oxygen is added to ambient water. We accounted for solvation of oxygen in water. 3) We predected that colloidal particles aggregate due to local phase separation (bridging) in near-critical binary mixture. 4) We showed various new effects when hydrophilic and hydrophobic ions (antagonistic salt) are added to water-oil mixtures.

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Class subject in charge

  • Statistical thermodynamics （2021academic year） Prophase  - 月5,月6

  • Statistical thermodynamics （2020academic year） Prophase  - 火3,火4

  • Quantum Chemistry 3 （2020academic year） Third semester  - 木3,木4

  • Quantum Chemistry 4 （2020academic year） Fourth semester  - 木3,木4

  • Quantum Chemistry II （2020academic year） 3rd and 4th semester  - 木3,木4