Updated on 2023/10/11

写真a

 
SAWADA Yasuyuki
 
Organization
Institutes of Innovation for Future Society Associate professor
Graduate School
Graduate School of Engineering
Title
Associate professor

Degree 1

  1. Ph.D ( 2012.10   Nagoya University ) 

Research Interests 1

  1. Biophysics

Research Areas 1

  1. Life Science / Biophysics

Research History 5

  1. Nagoya University   Associate professor

    2022.4

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    Country:Japan

  2. Nagoya University   Designated associate professor

    2020.10 - 2022.3

  3. Nagoya Keizai University   Associate professor

    2017.4 - 2020.9

  4. Nagoya University   Designated assistant professor

    2013.4 - 2017.3

  5. Nagoya University   Researcher

    2010.4 - 2013.3

Education 3

  1. Nagoya University

    2006.4 - 2010.3

  2. Nagoya University

    2004.4 - 2006.3

  3. Waseda University

    2000.4 - 2004.3

Professional Memberships 1

  1. 日本生物物理学会

    2005.4

 

Papers 15

  1. Highly durable graphene-encapsulated platinum-based electrocatalyst for oxygen reduction reactions synthesized by solution plasma process

    Park Jae-Hyeok, Kim Kyusung, Wang Xiaoyang, Huda Miftakhul, Sawada Yasuyuki, Matsuo Yutaka, Saito Nagahiro, Kawasumi Masaya

    JOURNAL OF POWER SOURCES   Vol. 580   2023.10

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    Publisher:Journal of Power Sources  

    Though expensive platinum (Pt) is used as catalyst for oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs), insufficient durability remains as a bottleneck for commercialization of PEFCs. Improving both catalytic performance and durability by graphene encapsulation is an attractive strategy to solve this problem. In this study, graphene-encapsulated PtFe core-shell catalyst is synthesized with dimethyl formamide (DMF) and a pair of Pt and Fe electrodes without using any metal salts by utilizing the solution plasma (SP) process. TEM and EELS results show synthesized PtFe nanoparticles are encapsulated with close to single-layered highly crystallized graphene. Although commercial Pt/C showed significant performance degradation (ECSA −33%, MA −68%) after 50,000 cycles of accelerated durability test (ADT), PtFe core-shell catalyst shows remarkably improved durability (ECSA −13%, MA −19%) while graphene shell clearly remains. The improved durability is more prominent in the single cell test, the decrease in maximum power density after 6000 cycles of ADT was significantly lower as −1.2%, compared to that of Pt/C (−52.1%). This study introduces a novel and attractive catalyst synthesis process by the SP method followed by heat treatments and suggests graphene encapsulation can improve long-term durability of catalyst while maintaining ORR activity.

    DOI: 10.1016/j.jpowsour.2023.233419

    Web of Science

    Scopus

  2. A novel force transduction pathway from a tension sensor to the gate in the mechano-gating of MscL channel

    Sawada Yasuyuki, Nomura Takeshi, Martinac Boris, Sokabe Masahiro

    FRONTIERS IN CHEMISTRY   Vol. 11   page: 1175443   2023.6

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    Language:English   Publisher:Frontiers in Chemistry  

    The bacterial mechanosensitive channel of large conductance MscL is activated exclusively by increased tension in the membrane bilayer. Despite many proposed models for MscL opening, its precise mechano-gating mechanism, particularly how the received force at the tension sensor transmits to the gate remains incomplete. Previous studies have shown that along with amphipathic N-terminus located near the cytoplasmic surface of the membrane, Phe78 residue near the outer surface also acts as a “tension sensor,” while Gly22 is a central constituent of the “hydrophobic gate.” Present study focused on elucidating the force transmission mechanism from the sensor Phe78 in the outer transmembrane helix (TM2) to the gate in the inner transmembrane helix (TM1) of MscL by applying the patch clamp and molecular dynamics (MD) simulations to the wild type MscL channel and its single mutants at the sensor (F78N), the gate (G22N) and their combination (G22N/F78N) double mutant. F78N MscL resulted in a severe loss-of-function, while G22N MscL caused a gain-of-function channel exhibiting spontaneous openings at the resting membrane tension. We initially speculated that the spontaneous opening in G22N mutant might occur without tension acting on Phe78 residue. To test this hypothesis, we examined the (G22N/F78N) double mutant, which unexpectedly exhibited neither spontaneous activity nor activity by a relatively high membrane tension. To understand the underlying mechanism, we conducted MD simulations and analyzed the force transduction pathway. Results showed that the mutation at the tension sensor (F78N) in TM2 caused decreased interaction of this residue not only with lipids, but also with a group of amino acids (Ile32-Leu36-Ile40) in the neighboring TM1 helix, which resulted in an inefficient force transmission to the gate-constituting amino acids on TM1. This change also induced a slight tilting of TM1 towards the membrane plane and decreased the size of the channel pore at the gate, which seems to be the major mechanism for the inhibition of spontaneous opening of the double mutant channel. More importantly, the newly identified interaction between the TM2 (Phe78) and adjacent TM1 (Ile32-Leu36-Ile40) helices seems to be an essential force transmitting mechanism for the stretch-dependent activation of MscL given that substitution of any one of these four amino acids with Asn resulted in severe loss-of-function MscL as reported in our previous work.

    DOI: 10.3389/fchem.2023.1175443

    Web of Science

    Scopus

    PubMed

  3. The Liquid-Mediated Synthesis and Performance Evaluation of Li-Zr-F Composite for Ion-Conduction Invited Reviewed

    Journal of Energy and Power Technology     2023.2

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    Language:English  

  4. Effect on percolation threshold of catalytic layer: Pt/N-Doped graphene shell onto SWCNT for ORR electrode

    Dechojarassri Duangkamol, Wang Xiaoyang, Chae Sangwoo, Sawada Yasuyuki, Hashimoto Takeshi, Saito Nagahiro

    FUEL CELLS   Vol. 23 ( 1 ) page: 4 - 14   2023.2

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    Publisher:Fuel Cells  

    A high-rate oxygen reduction reaction (ORR) is necessary for polymer electrolyte membrane fuel cells (PEMFC). In this work, by using a solution plasma technique, Pt catalytic particles coated with N-doped graphene (Pt-NG) were effectively produced at 25°C. According to transmission electron microscope images, the average diameter of Pt particles was 4 nm, while the graphene layer thickness was less than 1 nm. A catalytic layer of Pt-NG supported on single-walled carbon nanotubes (Pt-NG/SWCNT) was synthesized. Cyclic voltammetry was used to assess the ORR characteristics of Pt-NG/SWCNT catalytic layers. Only at a density of SWCNT to solvent ratio of 0.75 mg ml−1 were the ORR peaks clearly visible. Because of the high resistivity of SWCNT layers, the ORR peaks in other ranges, 0.4 mg ml−1 to 2.0 mg ml−1, were not clearly observed. The effect of SWCNT concentration on conductivity was proven to follow the basic concept of the percolation threshold.

    DOI: 10.1002/fuce.202200020

    Web of Science

    Scopus

  5. Preparation of lightweight, high hardness multi-component systems induced by partial oxidation and hard intermetallic phase formation

    Lee S., Chokradjaroen C., Sawada Y., Saito N.

    Journal of Materials Research     2023

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    Publisher:Journal of Materials Research  

    The ternary Mg–Al–Ti and quaternary Mg–Al–Ti–Cu systems were prepared by mechanical alloying in oxygen-lean atmosphere followed by spark plasma sintering. The ternary Mg–Al–Ti and quaternary Mg–Al–Ti–Cu systems which were sintered at 750 °C after 16 h milling showed the highest hardness of 509 and 947 HV with low densities of 2.9 and 3.9 g/cm3, respectively. The decrease in particle size and uniform dispersion of elements through optimization of the MA process induced the formation of uniform composite microstructure after SPS. Moreover, the addition of the fourth element, Cu, showed a significant impact on the improvement in hardness. This result was explained from the perspective of the microstructure and the electronic nature of elements. Our results provide a facile method for synthesizing oxide/metal composites from elemental powders without a separate oxidation process. Graphical abstract: [Figure not available: see fulltext.]

    DOI: 10.1557/s43578-023-01137-z

    Scopus

  6. Plasma-Solution Junction for the Formation of Carbon Material

    Niu Jiangqi, Chokradjaroen Chayanaphat, Sawada Yasuyuki, Wang Xiaoyang, Saito Nagahiro

    COATINGS   Vol. 12 ( 11 )   2022.11

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    Publisher:Coatings  

    The solution plasma process (SPP) can provide a low-temperature reaction field, leading to an effective synthesis of N-doped graphene with a high N content and well-structured planar structure. However, the interactions at the plasma–solution interface have not been well understood; therefore, it needs to be urgently explored to achieve the modulation of the SPP. Here, to address the knowledge gap, we experimentally determined the physical parameters of the spital distribution in the plasma phase, plasma–gas phase, and gas–liquid phase of the SPP by the Langmuir probe system with modification. Based on the assumption that plasma can act similarly to semiconductors with the Fermi level above the vacuum level, an energy band diagram of the plasma–solution junction could be proposed for the first time. It was observed that the Fermi level of the organic molecule could determine the magnitude of electron temperature in plasma, i.e., benzene produced the highest electron temperature, followed by phenol, toluene, and aniline. Finally, we found that the electron temperature at the interface could induce quenching, leading to the formation of multilayer large-size-domain carbon products. It provided significant evidence for achieving nonequilibrium plasma modulation of carbon nanomaterial synthesis.

    DOI: 10.3390/coatings12111607

    Web of Science

    Scopus

  7. ソリューションプラズマを用いた電池電極材料の開発とその電気化学特性 Invited Reviewed

    化学工業     2022.1

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    Authorship:Lead author   Language:Japanese  

  8. ソリューションプラズマによる電池材料の開発 Invited Reviewed

    日本材料科学会誌     2021

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    Authorship:Lead author   Language:Japanese  

  9. Biophysical Mechanisms of Membrane-Thickness-Dependent MscL Gating: An All-Atom Molecular Dynamics Study

    Katsuta Hiroki, Sawada Yasuyuki, Sokabe Masahiro

    LANGMUIR   Vol. 35 ( 23 ) page: 7432 - 7442   2019.6

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    Language:Japanese   Publisher:Langmuir  

    The bacterial mechanosensitive channel, MscL, is activated by membrane tension, acting as a safety valve to prevent cell lysis against hypotonic challenge. It has been established that its activation threshold decreases with membrane thickness, while the underlying mechanism remains to be solved. We performed all-atom molecular dynamics (MD) simulations for the initial opening process of MscL embedded in four different types of lipid bilayers with different thicknesses: 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC)), 1,2-dimyristoyl-glycero-3-phosphorylcholine (DMPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC). In response to membrane stretching, channel opening occurred only in the thinner membranes (DLPC and DMPC) in a thickness-dependent way. We found that the MscL opening was governed by the rate and degree of membrane thinning and that the channel opening was tightly associated with the tilting of transmembrane (TM) helices of MscL toward the membrane plane. Upon membrane stretching, the order parameter of acyl chains of thinner membranes (DLPC and DMPC) became smaller, whereas other thicker membranes (DPPC and DSPC) showed interdigitation with little changes in the order parameter. The decreased order parameter contributed much more to membrane thinning than did interdigitation. We conclude that the membrane-thickness-dependent MscL opening mainly arises from structural changes in MscL to match the altered membrane thickness by stretching.

    DOI: 10.1021/acs.langmuir.8b02074

    Web of Science

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    PubMed

  10. Corynebacterium glutamicum mechanosensitive channels: towards unpuzzling "glutamate efflux" for amino acid production.

    Nakayama Y, Hashimoto KI, Sawada Y, Sokabe M, Kawasaki H, Martinac B

    Biophysical reviews   Vol. 10 ( 5 ) page: 1359 - 1369   2018.10

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    Language:English   Publisher:Biophysical Reviews  

    Corynebacterium glutamicum has been utilized for industrial amino acid production, especially for monosodium glutamate (MSG), the food-additive for the “UMAMI” category of taste sensation, which is one of the five human basic tastes. Glutamate export from these cells is facilitated by the opening of mechanosensitive channels in the cell membrane within the bacterial cell envelope following specific treatments, such as biotin limitation, addition of Tween 40 or penicillin. A long-unsolved puzzle still remains how and why C. glutamicum mechanosensitive channels are activated by these treatments to export glutamate. Unlike mechanosensitive channels in other bacteria, these channels are not simply osmotic safety valves that prevent these bacteria from bursting upon a hypo-osmotic shock. They also function as metabolic valves to continuously release glutamate as components of a pump-and-leak mechanism regulating the cellular turgor pressure. Recent studies have demonstrated that the opening of the mechanosensitive channel, MscCG, mainly facilitates the efflux of glutamate and not of other amino acids and that the “force-from-lipids” gating mechanism of channels also applies to the MscCG channel. The bacterial types of mechanosensitive channels are found in cell-walled organisms from bacteria to land plants, where their physiological functions have been specialized beyond their basic function in bacterial osmoregulation. In the case of the C. glutamicum MscCG channels, they have evolved to function as specialized glutamate exporters.

    DOI: 10.1007/s12551-018-0452-1

    Scopus

    PubMed

  11. Molecular Dynamics Study for Exploring the Force Transmission Pathway in the Bacterial Mechanosensitive Channel MscL

    Sawada Yasuyuki, Nomura Takeshi, Sokabe Masahiro

    BIOPHYSICAL JOURNAL   Vol. 114 ( 3 ) page: 111A - 111A   2018.2

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  12. Molecular Dynamics Analysis on the Force Transmission Pathway via Inter-Subunit Pathway for Mechano-Gating of Bacterial Mechanosensitive Channel MscL

    Sawada Yasuyuki, Nomura Takeshi, Sokabe Masahiro

    BIOPHYSICAL JOURNAL   Vol. 112 ( 3 ) page: 533A - 533A   2017.2

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  13. 細胞はメカノストレスをどのように感知するのか? Invited Reviewed

    日本低温生物工学会誌     2012

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    Authorship:Lead author   Language:Japanese  

  14. 機械受容チャネルの一分子メカノバイオフィジックス Invited Reviewed

    日本生理学会誌     2012

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    Language:Japanese  

  15. 構造生物学が解き明かす機械受容チャネルの作動様式 Invited Reviewed

    血管医学     2010.11

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    Language:Japanese  

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Presentations 1

  1. 全固体フッ化物電池の開発とその評価技術の標準化 Invited

    澤田康之

    知の拠点あいち重点研究プロジェクトⅣ期 公開セミナー  2023.3.16  公益財団法人科学技術交流財団

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    Event date: 2023.3

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:知の拠点あいち  

Research Project for Joint Research, Competitive Funding, etc. 1

  1. 全固体フッ化物電池の開発とその評価技術の標準化

    Grant number:S8  2022.8 - 2025.3

    知の拠点あいち重点研究プロジェクトⅣ期  災害対策・自然利用・複合分野

    澤田康之

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\98000000

KAKENHI (Grants-in-Aid for Scientific Research) 2

  1. Elucidation of the gating mechanism of mechanosensitive channel by mechanical stimulation and amphipathic molecules

    Grant number:22K06847  2022.4 - 2025.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Authorship:Coinvestigator(s) 

  2. 食形態決定のための居宅用流動性測定器の開発と誤嚥性肺炎予防プログラムの構築

    Grant number:21K11094  2021.4 - 2024.3

    科学研究費助成事業  基盤研究(C)

    宇田川 孝子, 山中 崇, 福井 郁子, 高橋 徹, 澤田 康之, 福田 久子, 海老名 慧

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    Authorship:Coinvestigator(s) 

    高齢者の肺炎の7割以上が誤嚥性肺炎であり(Teramoto)、現状のままでは誤嚥性肺炎による死亡者は、更に増加すると予測されている(都健康安全研究センター)。また医療計画の見直しが必要な疾患とされ、予防が急務である。これまで誤嚥性肺炎の予防として、様々な増粘液状食品が開発されてきた。しかし、それら増粘液状食品における従来の物性測定機器では、流動性、分離性の情報が乏しく、最適な食形態の確立は困難である。本研究では、実際の消化管環境での物性の詳細が測定可能な流動性測定器を開発して誤嚥と流動性、分離性との関係を示す。その上で誤嚥性肺炎の予防に最適な食形態の確立を目指した予防プログラムの提案を目指す。

 

Teaching Experience (Off-campus) 9

  1. 生化学実験I

    2018.4 - 2020.9 Nagoya Keizai University)

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    Level:Undergraduate (specialized) 

  2. 運動生理学

    2017.4 - 2021.3 Nagoya Keizai University)

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    Level:Undergraduate (specialized) 

  3. 生物学

    2017.4 - 2020.9 Nagoya Keizai University)

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    Level:Undergraduate (liberal arts) 

  4. 栄養生理学研究

    2017.4 - 2020.9 Nagoya Keizai University)

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    Level:Postgraduate 

  5. 解剖生理学実習

    2017.4 - 2020.9 Nagoya Keizai University)

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    Level:Undergraduate (specialized) 

  6. 運動指導実習

    2017.4 - 2020.9 Nagoya Keizai University)

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    Level:Undergraduate (specialized) 

  7. 化学

    2017.4 - 2020.9 Nagoya Keizai University)

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    Level:Undergraduate (liberal arts) 

  8. 生物学

    2016.4 - 2017.3 Ogaki Women's College)

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    Level:Undergraduate (liberal arts) 

  9. 生理学

    2014.4 - 2017.3 Ogaki Women's College)

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    Level:Undergraduate (specialized)  Country:Japan

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Media Coverage 1

  1. 【知事会見】「知の拠点あいち重点研究プロジェクトIV期」で実施する27件の研究テーマを決定しました! Internet

    https://www.pref.aichi.jp/press-release/juten4kettei.html  2022.7