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YANO Yohko

    Department of Science　Professor
Last Updated :2024/04/23

Researcher Information

URL

J-Global ID

Research Interests

  • 超音波霧化分離   ナノリスク   液体   X線回折   X線反射率   表面・界面   liquid-vapor interfaces   surface   X-ray diffraction   X-ray reflection   

Research Areas

  • Natural sciences / Bio-, chemical, and soft-matter physics

Academic & Professional Experience

  • 2011/04 - Today  Kindai UniversityFaculty of Science and Engineering, Department of Science准教授
  • 2008/04 - 2011/03  Ritsumeikan University総合理工学研究機構チェアプロフェッサー
  • 2006/02 - 2007/09  Ritsumeikan UniversityCOE推進機構助（准）教授
  • 1992 - 2006  :学習院大学理学部化学科 助手
  • 2001 - 2002  :ハーバード大学・客員研究員（仁科記念財団海外派遣研究者） [国外]

Association Memberships

  • 日本化学会   日本物理学会   日本結晶学会   分子科学会   THE JAPANESE SOCIETY FOR SYNCHROTRON RADIATION RESEARCH   THE BIOPHYSICAL SOCIETY OF JAPAN   

Published Papers

  • Yohko F. Yano; Toshiaki Ina; Tomoya Uruga
    COLLOIDS AND INTERFACES MDPI 5 (2) 2021/06 [Refereed][Invited]
     
    Biological membrane is composed of lipid molecules, because of its fluidity, it is possible to carry out physiological functions. Therefore, it is important to study the hydrodynamic properties of membranes toward understanding its function. Here, we observed the dynamical behavior of a lipid monolayer on the water surface under Marangoni flow. By using X-ray reflectometry, we obtained the tilt angle of the hydrocarbon chains of the lipid at different surface pressures. Comparing them with the dynamical surface pressure under Marangoni flow, it was found that the lipid molecules in rotational rather than translational motion. At low surface pressure, the molecular tilt angle is reduced by 20 degrees, even though the molecular area is reduced by at most 10%.
  • Yohko F. Yano; Hiroki Tada; Etsuo Arakawa; Wolfgang Voegeli; Toshiaki Ina; Tomoya Uruga; Tadashi Matsushita
    The Journal of Physical Chemistry Letters American Chemical Society (ACS) 11 (15) 6330 - 6336 1948-7185 2020/08 [Refereed]
     
    Regularly recurring phenomena are a common and important part of life. Such rhythmic behaviors are often seen in nonliving systems under far-from-equilibrium conditions. The study of simple nonliving systems provides clues for improving our understanding of the origin of biological rhythms. Here, we focus on the spontaneous oscillation of surface tension associated with an intermittent Marangoni convective flow generated by two types of surfactants, those that are partially soluble (long chain alcohols) and insoluble (lipids) in water. In this system, we find that the collective motions of two surfactants interact with each other in a systematic manner to control a stable periodic motion: The alcohol molecules (donor) produce a Marangoni flow, and the lipid molecules (acceptor) in a monolayer push the flow back. The shape of the surface tension oscillation can be explained by the viscoelastic properties of the acceptor surfactant, whereas the period of the surface tension oscillation has been explained by the physical properties of the donor surfactant. A recently developed time-resolved X-ray surface scattering technique enables the dynamic structure of the water surface under flow to be determined. We have repeatedly observed that lipid molecules at the air-water interface become regularly oriented normal to the surface at every onset of the Marangoni convective flow.
  • Development of Simultaneous Measurement System
    Mari OKUNO; Syoichi EBATA; Toshiki NISHIKAWA; Yuya OGAWA
    Adv. X-Ray. Chem. Anal., Japan 50 161 - 168 2019/03 [Refereed]
    ダウンロード
  • Yohko F. Yano; Etsuo Arakawa; Wolfgang Voegeli; Chika Kamezawa; Tadashi Matsushita
    Journal of Physical Chemistry B American Chemical Society 122 (17) 4662 - 4666 1520-5207 2018/05 [Refereed]
     
    We present the results of time-resolved X-ray reflectivity measurements carried out to investigate the early stage of protein adsorption and deformation at an air-water interface. Three globular proteins [lysozyme, myoglobin, and bovine serum albumin (BSA)] were studied, and we observed that the proteins adsorbed at the air-water interface initially possessed a thinner conformation than their native structures. The degree of deformation increased in the order myoglobin < lysozyme < BSA, which was inconsistent with the order of molecular flexibility. The initial rate of protein adsorption increased in the order lysozyme < BSA < myoglobin as determined by the dynamic surface tension. More flexible proteins generally adsorb at the interface more rapidly however, proteins with hydrophobic patches on the protein surface, such as myoglobin, adsorb at the interface with little deformation. These results provide evidence that protein unfolding during adsorption only takes place if the kinetics of adsorption are similar to or slower than the kinetics of unfolding.
  • Wolfgang Voegeli; Chika Kamezawa; Etsuo Arakawa; Yohko F. Yano; Tetsuroh Shirasawa; Toshio Takahashi; Tadashi Matsushita
    JOURNAL OF APPLIED CRYSTALLOGRAPHY INT UNION CRYSTALLOGRAPHY 50 570 - 575 1600-5767 2017/04 [Refereed]
     
    An X-ray reflectometer using a laboratory X-ray source for quick measurements of the specular X-ray reflectivity curve is presented. It uses a bent-twisted crystal to monochromatize and focus the diverging X-rays (Cu K alpha(1)) from a laboratory point source onto the sample. The reflected X-rays are recorded with a two-dimensional detector. Reflectivity curves can be measured without rotating the sample, detector or X-ray source during measurements. The instrument can separate the specularly reflected X-rays from the diffuse scattering background, so low reflectivities can be measured accurately. For a gold thin film on silicon, the reflectivity down to the order of 10(-6) was obtained with a measurement time of 100 s and that down to 10(-5) with a measurement time of 10 s. Reflectivity curves of a silicon wafer and a liquid ethylene glycol surface are shown as well. Time-resolved measurements of a TiO2 surface during UV irradiation are also reported.
  • Yohko F. Yano; Yuki Kobayashi; Toshiaki Ina; Kiyofumi Nitta; Tomoya Uruga
    LANGMUIR AMER CHEMICAL SOC 32 (38) 9892 - 9898 0743-7463 2016/09 
    Hofmeister anion effects on adsorption kinetics of the positively charged lysozyme (pH < pI) at an air-water interface were studied by surface tension measurements and time-resolved X-ray reflectometry. In the salt-free solution, the protein adsorption rate increases with decreasing the net positive charge of lysozyme. When salt ions are dissolved in water, the protein adsorption rate drastically increases, and the rate is following an inverse Hoffmeister series (Br- > Cl- > F-). This is the result of the strongly polarized halide anion Br- being attracted to the adsorbed protein layer due to strong interaction with local electric field, while weakly polarized anion F- having no ability to penetrate the protein layer. In X-ray reflection studies, we observed that the lysozyme molecules initially adsorbed on the air-water interface have a flat unfolded structure as previously reported in the salt-free solution. In contrast, in the concentrated salt solutions, the lysozyme molecules begin to refold during adsorption. This protein refolding as a result of protein-protein rearrangements may be a precursor phenomenon of crystallization. The refolding is most significant for Cl-, which is a good crystallization agent, whereas it is less observed for the strongly hydrated F-. It is widely known in the bulk state that kosmotropic anions tend to precipitate proteins but at the same time stabilize proteins against denaturing. On the other hand, at the air-water interface where adsorbed proteins usually unfold, we observed chaotropic anions strongly bound to proteins that reduce electrostatic repulsion between protein molecules, and subsequently they induce protein refolding whereas the kosmotropic anions do not.
  • Yohko F. Yano; Etsuo Arakawa; Wolfgang Voegeli; Tadashi Matsushita
    JOURNAL OF SYNCHROTRON RADIATION WILEY-BLACKWELL 20 (6) 980 - 983 0909-0495 2013/11 
    Protein unfolding at an air-water interface has been demonstrated such that the X-ray reflectivity can be measured with an acquisition time of 1 s using a recently developed simultaneous multiple-angle-wavelength-dispersive X-ray reflectometer. This has enabled the electron density profile of the adsorbed protein molecules to be obtained in real time. A globular protein, lysozyme, adsorbed at the air-water interface is found to unfold into a flat shape within 1 s.
  • Yohko F. Yano; Tomoya Uruga
    CHEMICAL PHYSICS ELSEVIER SCIENCE BV 419 153 - 155 0301-0104 2013/06 
    The density profiles of lysozyme layers at the air-water interface before and after adding salt were determined by X-ray reflection. After adding salt, the density of the lysozyme (LSZ) layers decreases, whereas the thickness drastically increases. The salt ions are considered to increase the LSZ-LSZ interaction, and consequently decrease the surface activity of LSZ, allow adsorbed lysozyme molecules crystallize. (C) 2013 Elsevier B. V. All rights reserved.
  • Hiroki Matsubara; Tetsumasa Takaichi; Takanori Takiue; Hajime Tanida; Tomoya Uruga; Yohko F. Yano; Makoto Aratonol
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN CHEMICAL SOC JAPAN 86 (4) 492 - 496 0009-2673 2013/04 
    X-ray reflectivity measurements were applied to hexadecane wetting film on aqueous solutions of hexadecyltrimethylammonium bromide (CTAB) and tetradecyltrimethylammonium bromide (TTAB). In both cases, the monolayers in which oil molecules are penetrated from hexadecane droplets into surfactant-adsorbed films were found at room temperature. Upon cooling, they showed first-order freezing transitions, however, it was also confirmed that the structures of freezing films were qualitatively different: hexadecane molecules were frozen together with CTAB to form mixed solid monolayer in CTAB-hexadecane while the frozen hexadecane monolayer wetted mixed liquid monolayer in TTAB-hexadecane.
  • YANO Yohko F.
    MEMBRANE THE MEMBRANE SOCIETY OF JAPAN 38 (2) 64 - 69 0385-1036 2013/03 
    X-ray reflectivity is a non-destructive characterization technique for thin films. Either solids or liquids, inorganic or organic compounds can be analyzed. Although this technique has the disadvantages that relatively wide and flat samples are necessary, they are overcome by using synchrotron radiation sources. In this article, characterization of protein layers bound to supported lipid bilayers and time-resolved measurements for protein layers formed on a water surface are shown for examples.
  • E. Arakawa; W. Voegeli; T. Matsushita; Y. F. Yano; T. Hatano
    Journal of Physics: Conference Series Institute of Physics Publishing 425 (9) 1742-6596 2013 [Refereed]
     
    The whole profile of the specular X-ray reflectivity curve was simultaneously and quickly measured with no need to rotate the specimen, the detector or the monochromator crystal. A white synchrotron beam from a bending magnet source is incident on a bent-twisted silicon (111) crystal polychromator that produces a convergent X-ray beam with a continuously varying wavelength (energy) and glancing angle to the specimen surface. This convergent X-ray beam was specularly reflected in the vertical direction by the specimen placed at the focus. The normalized spatial distribution across the beam direction of the reflected beam represents a specular X-ray reflectivity curve because each position along the line recorded on the two dimensional detector surface corresponds to a different momentum transfer. Reflectivity curves from a (001) silicon wafer, a nickel thin film on a silicon substrate, and a water surface were measured with data collection times of 0.001-100 s, 0.01-100 s, and 1.0-1000 s, respectively. The simultaneously covered momentum transfer range was 0.03-0.52 Å-1 for solid specimens and 0-0.41 Å-1 for liquid specimen. © Published under licence by IOP Publishing Ltd.
  • Voegeli W; Matsushita T; Arakawa E; Shirasawa T; Takahashi T; Yano Y.F
    Journal of Physics: Conference Series 425 (PART 9) 2013 [Refereed]
  • Tadashi Matsushita; Etsuo Arakawa; Wolfgang Voegeli; Yohko F. Yano
    JOURNAL OF SYNCHROTRON RADIATION WILEY-BLACKWELL 20 (1) 80 - 88 0909-0495 2013/01 
    An X-ray reflectometer has been developed, which can simultaneously measure the whole specular X-ray reflectivity curve with no need for rotation of the sample, detector or monochromator crystal during the measurement. A bent-twisted crystal polychromator is used to realise a convergent X-ray beam which has continuously varying energy E (wavelength lambda) and glancing angle alpha to the sample surface as a function of horizontal direction. This convergent beam is reflected in the vertical direction by the sample placed horizontally at the focus and then diverges horizontally and vertically. The normalized intensity distribution of the reflected beam measured downstream of the specimen with a two-dimensional pixel array detector (PILATUS 100K) represents the reflectivity curve. Specular X-ray reflectivity curves were measured from a commercially available silicon (100) wafer, a thin gold film coated on a silicon single-crystal substrate and the surface of liquid ethylene glycol with data collection times of 0.01 to 1000 s using synchrotron radiation from a bending-magnet source of a 6.5 GeV electron storage ring. A typical value of the simultaneously covered range of the momentum transfer was 0.01-0.45 angstrom(-1) for the silicon wafer sample. The potential of this reflectometer for time-resolved X-ray studies of irreversible structural changes is discussed.
  • Yohko F. Yano
    JOURNAL OF PHYSICS-CONDENSED MATTER IOP PUBLISHING LTD 24 (50) 50310  0953-8984 2012/12 [Refereed][Invited]
     
    The conformation of protein molecules is determined by a balance of various forces, including van der Waals attraction, electrostatic interaction, hydrogen bonding, and conformational entropy. When protein molecules encounter an interface, they are often adsorbed on the interface. The conformation of an adsorbed protein molecule strongly depends on the interaction between the protein and the interface. Recent time-resolved investigations have revealed that protein conformation changes during the adsorption process due to the protein-protein interaction increasing with increasing interface coverage. External conditions also affect the protein conformation. This review considers recent dynamic observations of protein adsorption at various interfaces and their implications for the kinetics of protein unfolding at interfaces.
  • Ken-Ichi Saitow; Yoshinori Okamoto; Yohko F. Yano
    Journal of Physical Chemistry C 116 (32) 17252 - 17258 1932-7447 2012/08 [Refereed]
     
    The nanosecond pulsed laser ablation of a gold plate at the excitation wavelength of 532 nm was conducted in the supercritical fluid of dipolar trifluoromethane (CHF 3). The generation of gold nanoparticles was investigated as a function of the fluid density that corresponded to changes in the permittivity and thermal properties over the wide ranges. The analysis of data from electron microscopy and small-angle X-ray scattering (SAXS) revealed that the principal product is a gold nanonetwork with length up to a few 10 μm and a branched structure. The gold nanonetwork consisted of gold nanospheres with an average diameter of 20 nm and a mass fractal structure. The mass fractal dimension of the nanonetwork changed by the fluid density, and its dimension was attributed to the number of the nanospheres. It was clarified that not the fluid thermal properties but the ambient dielectricity and polarization energy during the ablation are responsible for the morphology and number of gold nanoparticles. This is the first report of (i) fractal structure of gold nanoparticles created by the ablation, (ii) ablation mechanism in dipolar and nondipolar fluids, and (iii) a chemical-free nanoparticle synthesis in a dipolar fluid. © 2012 American Chemical Society.
  • Yohko F. Yano; Tomoya Uruga; Hajime Tanida; Yasuko Terada; Hironari Yamada
    JOURNAL OF PHYSICAL CHEMISTRY LETTERS AMER CHEMICAL SOC 2 (9) 995 - 999 1948-7185 2011/05 [Refereed]
     
    A protein salting-out process is directly observed at an air-water interface. By using time-resolved X-ray specular reflectivity and off-specular diffuse scattering, we identified several key stages in the adsorption of hen egg white lysozyme in a concentrated NaCl solution, (1) adsorption-induced unfolding, (2) monolayer formation with unfolded proteins, (3) protein refolding, and (4) island formation with the refolded proteins. Stages 3 and 4 are not observed either at the isoelectric point or in the salt-free solution, suggesting that they are induced by screening of the positive charges in the lysozyme by chloride ions. It is considered that the hydrated salt ions act to minimize the water-accessible surface area of the protein, not only enhancing protein dehydration (stages 1 and 2) but also assisting in protein refolding and association (stages 3 and 4). These results provide insight into the early stages of protein crystal nucleation.
  • YANO Yohko F.
    Earozoru Kenkyu Japan Association of Aerosol Science and Technology 26 (1) 18 - 23 0912-2834 2011 
    Ultrasonic atomization, in general, generates mist of liquid droplets with the diameter of micrometer order. Recently, our measurements with small-angle X-ray scattering (SAXS) at SPring-8 have revealed that the droplets of 1 nm dominate the whole population of atomized mist of ethanol. This article describes the details of SAXS measurements and discusess the mechanisms of the nano-sized droplet generation.
  • Wolfgang Voegeli; Tadashi Matsushita; Etsuo Arakawa; Yasuo Higashi; Yohko F. Yano
    ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES INT UNION CRYSTALLOGRAPHY 67 C340 - C340 2053-2733 2011
  • Yohko F. Yano; Tomoya Uruga; Hajime Tanida; Hidenori Toyokawa; Yasuko Terada; Hironari Yamada
    JOURNAL OF SYNCHROTRON RADIATION INT UNION CRYSTALLOGRAPHY 17 (4) 511 - 516 0909-0495 2010/07 
    An X-ray reflectometer for simultaneous measurement of specular and off-specular reflection of liquid surfaces is described. The reflectometer, equipped with a two-dimensional single X-ray photon-counting pixel array detector obtained the full range of X-ray specular and off-specular reflections in an extremely short time (1 s). Both the specular and off-specular reflection of water exhibited good agreement with the predicted capillary-wave theory within the appropriate instrumental resolution. The approach is also demonstrated on an aqueous solution of 1-dodecyl-3-methylimidazolium chloride. The monolayer in which the dodecyl chain faces upwards and the Cl- anion locates next to the imidazolium ring formed on the water surface was found to be laterally homogeneous. The use of a pixel array detector will be particularly powerful for in situ measurements to investigate both out-of-plane and in-plane structures simultaneously, not only for liquid surfaces but also for other thin films.
  • 矢野陽子; 宇留賀朋哉; 谷田肇; 豊川秀訓; 寺田靖子; 山田廣成
    分析化学 59 (6) 437 - 445 0525-1931 2010 [Refereed]
  • 矢野陽子; 宇留賀朋哉; 谷田肇; 豊川秀訓; 寺田靖子; 山田廣成
    X線分析の進歩 41 117 - 125 0911-7806 2010 [Refereed]
  • Y. F. Yano; T. Uruga; H. Tanida; H. Toyokawa; Y. Terada; M. Takagaki; H. Yamada
    EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS EDP SCIENCES S A 167 101 - 105 1951-6355 2009/02 [Refereed]
     
    X-ray reflectivity measurements of liquid surfaces were demonstrated using a recently developed liquid interface reflectometer at SPring-8. The reflectometer, equipped with a two-dimensional hybrid pixel array detector (PILATUS), achieved x-ray reflectivity towards 10(-9) with an integration time at each angle of only 1 sec, offering enormous potential for rapid measurements. Time-resolved measurements at a time resolution of 1 min were performed on the adsorption process of a globular protein lysozyme on a water/air interface.
  • 矢野陽子; 松浦一雄; 田中雅彦; 井上勝晶
    Advances in X-ray chemical analysis アグネ技術センタ- 40 (40) 299 - 305 0911-7806 2009
  • Yohko F. Yano; Tomoya Uruga; Hajime Tanida; Hidenori Toyokawa; Yasuko Terada; Masafumi Takagaki; Hironari Yamada
    Trans. MRS-J 34 631 - 638 2009
  • Yohko F. Yano; Tomoya Uruga; Hajime Tanida; Hidenori Toyokawa; Yasuko Terada; Masafumi Takagaki; Hironari Yamada
    LANGMUIR AMER CHEMICAL SOC 25 (1) 32 - 35 0743-7463 2009/01 [Refereed]
     
    Time-resolved X-ray reflectivity measurements for lysozyme (LSZ) adsorbed at an air/water interface were performed to study the mechanism of adsorption-induced protein unfolding. The time dependence of the density profile at the air/water interface revealed that the molecular conformation changed significantly during adsorption. Taking into account previous work using Fourier transform infrared (FTIR) spectroscopy, we propose that the LSZ molecules initially adsorbed on the air/watcr interface have a flat unfolded structure, forming antiparallel P-sheets as a result of hydrophobic interactions with the gas phase. In contrast, as adsorption continues, a second layer forms in which the molecules have a very loose structure having random coils as a result of hydrophilic interactions with the hydrophilic groups that protrude from the first layer.
  • Yohko F. Yano; Hironari Yamada
    ANALYTICAL SCIENCES JAPAN SOC ANALYTICAL CHEMISTRY 24 (10) 1269 - 1271 0910-6340 2008/10 [Refereed]
     
    Grazing-incidence x-ray diffraction measurements were carried out to observe the surface structure of [bmim][PF6]. At an incident angle of less than the critical angle, a diffraction pattern from 10 nm beneath the surface was obtained. A broad Debye-Scherrer ring was observed in the diffraction patterns, indicating that the [bmim][PF6] molecules near the surface are randomly orientated, similar to those in the bulk liquid. The distance of the. nearest anions was estimated to be 4.2 angstrom, which is very close to that for bulk [bmim][I], suggesting that the liquid structure of [bmim][PF6] is determined by the packing of the cation.
  • Yohko F. Yano; Kazuo Matsuura; Tetsuo Fukazu; Fusatsugu Abe; Akihiro Wakisaka; Hitomi Kobara; Kazuyuki Kaneko; Atsushi Kumagai; Yoshio Katsuya; Masahiko Tanaka
    JOURNAL OF CHEMICAL PHYSICS AMER INST PHYSICS 127 (3) 031101  0021-9606 2007/07 [Refereed]
     
    Small-angle x-ray scattering measurements using a brilliant x-ray source revealed nanometer sized liquid droplets in a mist formed by ultrasonic atomization. Ultrasonic atomization of ethanol-water mixtures produced a combination of water-rich droplets of micrometer order and ethanol-rich droplets as small as 1 nm, which is 10(-3) times smaller than the predicted size. These sizes were also obtained for mists generated from the pure liquids. These results will help to clarify the mechanism of "ultrasonic ethanol separation," which has the potential to become an alternative to distillation. (C) 2007 American Institute of Physics.
  • Yohko F. Yano
    Portable Synchrotron Light Sources and Advanced Applications AMER INST PHYSICS 902 93 - 95 0094-243X 2007 [Refereed]
     
    X-ray reflectivity profiles of human lactoferrin absorbed at water interfaces have calculated using the structure determined by neutron reflection measurements [Lu et al., Langmuir, 21, 3354 (2005)]. A significant difference in the expected profiles was observed between the unfolding lactoferrin at the interfaces and aqueous subphase itself. Time-resolved X-ray reflectivity measurements are proposed to probe the protein adsorbing process at interfaces.
  • YF Yano
    JOURNAL OF CHEMICAL PHYSICS AMER INST PHYSICS 116 (18) 8093 - 8096 0021-9606 2002/05 [Refereed]
     
    The surface structure of 2-butoxyethanol (BE)-water mixtures at 300 K was studied by x-ray reflection and surface tension measurements. It is striking that a finite intrinsic surface width attributed to the surface excess BE was observed only below BE mole fraction x(BE)=0.017 where the pseudophase transition occurs in the bulk. The monolayer formation at x(BE)approximate to0.005 was found from the result of a curve fitting to the measured reflectivities by using the density profile of a single-layer "box" model in which interfaces were smeared by thermal capillary waves. (C) 2002 American Institute of Physics.
  • YF Yano; T Iijima
    JOURNAL OF CHEMICAL PHYSICS AMER INST PHYSICS 112 (21) 9607 - 9616 0021-9606 2000/06 [Refereed]
     
    We have constructed a grazing incidence x-ray reflection system for liquid-vapor interfaces by use of an imaging plate as an area detector. The reflectivity data were obtained with high resolution even by use of a conventional x-ray tube. The surface reflectivity measurements for pure water, ethanol and 2-butoxyethanol were performed and the values of the surface roughness were obtained as 4.1 +/- 0.1, 7.1 +/- 0.3 and 6.2 +/- 0.2 Angstrom, respectively. For water, slight broadening of reflection peaks was observed. This was caused by the surface curvature due to the large surface tension. By fitting the reflection profiles, the radius of curvature was found to be nearly 100 m for water and ten times larger for ethanol and 2-butoxyethanol. (C) 2000 American Institute of Physics. [S0021-9606(00)70321-7].
  • Yohko F. Yano; Takao Iijima
    ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES INT UNION CRYSTALLOGRAPHY 55 509 - 509 2053-2733 1999
  • A Takahashi; YF Yano; T Iijima
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN CHEMICAL SOC JAPAN 71 (9) 2081 - 2086 0009-2673 1998/09 [Refereed]
     
    The structure of liquid chloroform has been investigated by energy-dispersive X-ray diffraction. For the stability of the sample thickness, even for a volatile liquid, a glass capillary tube has been used as a sample container. The intensity function has been accounted for by a bcc (body-centered cubic)-like local lattice structure model with a lattice constant of 6.24 Angstrom. However, it has been necessary to replace a fraction (34%) of the nearest neighbors by super-near configurations in which molecules are rather tightly correlated. The correlation is, however, rapidly lost as the distance between molecules increases, and the long range structure is characterized by a large Prins parameter. The structure of liquid chloroform is much less ordered than that of carbon tetrachloride.

Books etc

  • 日本の結晶学(II)
    矢野 陽子 (Contributor)日本結晶学会 2014/07
  • 放射光が拓く化学の現在と未来
    矢野 陽子 (Contributor界面研究への放射光利用)化学同人 2014/01
  • X線反射率法入門
    講談社サイエンティフィク 2009
  • 実験化学講座 第5版 基礎入門編[II]（基本的な測定技術）
    丸善 2003

Works

  • X線回折法によるナノ粒子分散液体の構造評価 【概要】産総研では凝集性の高いカーボンナノチューブ（CNT)をマトリックス粉砕法(水飴法）で切断・分散し、分散水溶液を調製する研究を行なっている。しかしながら、調製した水溶液中のCNTの分散状態を評価することは極めて難しく、特に100nm以下のサイズの評価は測定誤差が大きい。本研究では、X線回折法を用い、その評価法を開発する。
    2006/07 -2007/03
  • 超音波霧化における膜透過面に関する最大必要細孔径の研究 【概要】超音波霧化分離法によるエタノールの濃縮において、エタノール濃縮効率を上げるためには、発生する霧の粒径を知ることが重要である。本研究ではＸ線小角散乱法を用いて、超音波霧の粒径分布をナノレベルで解析することを目的とする。
    2004/06

MISC

Awards & Honors

  • 2010 第3回資生堂女性研究者サイエンスグラント
     JPN
  • 2006 日本分析化学会 X線分析懇談会 第1回浅田栄一賞
     JPN
  • 2004 日本化学会春季年会 第18回若い世代の特別講演証
     JPN
  • 1996 "2nd prize of poster award in the International Schools and Conference on X-Ray Analytical Methods, Sydney Australia"

Research Grants & Projects

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2022/04 -2026/03 
    Author : 矢野 陽子
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2017/04 -2020/03 
    Author : Yano Yohko
     
    Regularly recurring phenomena are a common and important part of life activity. Such rhythmic behaviors are often seen in non-living systems under far-from-equilibrium conditions. The study of simple non-living systems provides clues to understand the origin of biological rhythms. Here, we focus on the spontaneous oscillation of surface tension associated with an intermittent Marangoni convective flow generated by two types of surfactants, partially soluble and insoluble in water. In this system, we find the collective motions of two surfactants interact with each other in a systematic manner to control a stable periodic motion. Recently developed time-resolved X-ray surface scattering technique enable the dynamical structure of the water surface under flow to be determined. We have repeatedly observed that lipid molecules at the air-water interface become regularly oriented normal to the surface at every onset of the Marangoni convective flow.
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2012/04 -2015/03 
    Author : YANO Yohko
     
    We have constructed an energy dispersive X-ray reflectometer combined with ATR-FTIR system. The reflectivity data were obtained with high resolution even by use of a conventional x-ray tube. The reflectometer equipped achieved x-ray reflectivity towards 10-5 with the integration time of only 10 sec. We have also succeeded to perform X-ray diffraction and FT-IR simultaneously. having enormous potential for various measurements.
  • 日本学術振興会：科学研究費助成事業
    Date (from‐to) : 2010 -2011 
    Author : 矢野 陽子
     
    人工組織や生体物質を使った新しい機能性材料の開発など、医学的および技術的応用の両面においても生体物質と界面の相互作用を知ることは非常に重要である。昨年度は、X線反射率とその周囲に生じる微弱な散乱を精度良く計測することにより、タンパク質の界面垂直・水平方向の構造情報を同時に取得する手法を確立した。当該年度はこれを用いて様々な条件における球状タンパク質リゾチームの界面吸着過程を観測し、結果を体系化した。概要を以下にまとめる。 一般にタンパク質の界面吸着のドライビングフォースは、疎水性界面ならば疎水性相互作用、親水性界面ならば静電相互作用となり、前者は後者よりも大きなコンフォメーションの変化を引き起こす。また、母液の濃度が低いほど、界面吸着速度は遅くなり、より大きなコンフォメーションの変化を誘発する。 等電点よりも低いpHの場合は、リゾチームは正に帯電するため、リゾチーム同士の静電反発が大きくなって吸着速度は低下する。一方、等電点においては、吸着速度は増加するが、分子内の静電反発によって大きく変性する。イオン強度が大きくなると、リゾチーム同士の静電反発が遮蔽されるため、リゾチーム同士のファンデルワールス力が強くなる。 タンパク質の界面吸着のドライビングフォースは、吸着の初期段階ではタンパク質と界面の相互作用だけを考えれば良いが、界面被覆率が増加するに従って、タンパク質同士の相互作用が大きくなる。その結果、タンパク質のコンフォメーションは、吸着後も徐々に変化する。よって、このような変化を追跡できる測定法の開発は非常に重要である。
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2008 -2010 
    Author : YANO Yohko
     
    The liquid droplets produced from ethanol-water mixtures by ultrasonic atomization are enriched with ethanol which are as small as 1 nm. In this project, we revealed that the generation of the nano-sized droplet enhances by the three factors : microstructure of the liquid, the liquid/gas equilibrium and the energy input.
  • 日本学術振興会：科学研究費助成事業
    Date (from‐to) : 2008 -2009 
    Author : 矢野 陽子
     
    アルキル鎖を持つイミダゾリウム塩【C_n mim】X(nは炭素数Xはハロゲン)は、アルキル鎖の長さが増すと界面活性剤としての性質が際立ってくる。n>6でミセル形成が観測されており、臨界ミセル濃度(cmc)はnと伴に低濃度側にシフトする。一方、同じ炭素数でアニオン種を変えた場合cmcはほとんど変わらないが、アニオン半径が大きくなるとミセル中の会合体数も多くなることが報告されている。水溶液中では、アルキル鎖同士の疎水性相互作用、カチオンとアニオンの静電相互作用、アニオンと水の水和が競合してミセル会合体を形成する。このような相互作用の寄与を分離するためには、水溶液中のミセルではなく共存する水溶液表面の分子膜の構造に着目したほうが良いと考え、本研究ではX線反射率測定を試みた。 その結果、臨界ミセル濃度付近の【C_n mim】X(n=8,12、X=Cl,Br)水溶液はアルキル鎖のパッキングが50%で、アニオンがイミダゾリウム環の隣に配置した表面単分子膜を形成していることがわかった。[C_12mim】Cl水溶液の場合は、濃度の増加に伴って、Crのポジションが表面近くに移動すること、[C_8mim]X水溶液の場合は、Br^-の方が表面に近く位置していることを考えると、アニオンのポジションはイミダゾリウム環の静電相互作用が最も支配的であるが、水和の影響をわずかに受けることがわかった。 一方、反射率測定の際に得られる散漫散乱強度を検討したところ、上の表面単分子膜が面内方向に非常に均一な膜であることがわかった。
  • 日本学術振興会：科学研究費助成事業
    Date (from‐to) : 2006 -2007 
    Author : 矢野 陽子
     
    X線反射率法(XR)とは、X線を試料に対してすれすれに入射させ、全反射角度近傍での反射率を観測することにより、表面深さ方向の密度分布を得ようというものである。入射角の-4乗で変化するX線強度を精度良く測定しなければならないため、分子レベルで構造を決定するには放射光源を用いるのが常套手段となっている。これまで国内の放射光施設には、そのような装置を備えたビームラインが存在しなかったが、本研究は、高輝度光科学研究センターの宇留賀らとともにSPring-8に溶液界面反射率計を立ち上げることに大いに貢献した。イオン液体についての測定にはまだ至っていないが、測定時間わずか2分というこの装置は、水溶液表面にイオン液体が吸着する過程といったダイナミクス研究に威力を発揮すると思われる。 一方、反射X線の周囲に生じる回折像(表面X線回折、GIXD)を解析すると、水平面内の構造情報も得ることができる。本研究では実験室の反射率計を用い、X線の入射角を制御して表面深さ10nmの回折パターンを得ることに成功した。ニートなイオン液体のGIXD測定を行ったところ、[bmim]PF_6表面の回折パターンは、片柳らが報告したバルクの[bmim]I片柳らが報告したバルクの[bmim]Iのパターンと非常に良く似ており、表面構造はカチオンが支配していることがわかった。一方、[bmim]TFSIのパターンは全く異なっており、かさ高いアニオンが構造を支配していることがうかがえる。
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2004 -2005 
    Author : YANO Yoko F.
     
    We have tried to measure X-ray reflectivity of one of ionic liquids, [bmin]Bf4. As the result, a small deviation from Fresnel s law for the ideal flat surface was observed at highest angle which we could measure. To obtain the data at higher angle, higher incident beam intensity was necessary. Therefore, a parabolic multilayer X-ray optics was applied for the reflectometer as a monochromater instead of the perfect crystal monochromater. Not to move a heavy X-ray source, a new geometry in which only the parabolic multilayer rotates around the X-ray focal point, was attempted successfully. Comparing with a Ge111 monochromator, we obtained a good X-ray beam with 25 times higher intensity and lower divergence. Reflectivity data for liquid glycerin were measured for demonstration. We will try to measure the reflectivity of the ionic liquid by using the reformed reflectometer.
  • 日本学術振興会：科学研究費助成事業
    Date (from‐to) : 1999 -2000 
    Author : 矢野 陽子
     
    2-ブトキシエタノール(BE)水溶液は、モル分率0.07、約50℃で2相分離を起すことが知られている。常温においては1相であるが、ミクロな混合状態が異なる3つの濃度領域(27℃では、モル分率0<領域I<0.017
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 1996 -1997 
    Author : IIJIMA Takao; YANO Yohko
     
    We have developed a grazing incidence x-ray reflection apparatus for liquid-vapor interfaces using a conventional x-ray tube (Cu K_,2.2kW). A special geometry has been necessitated by the restriction that the liquid surface is horizontal. The main features of our apparatus are as follows. Highly collimated and monochromated x-ray beams are generated using an asymmetrically cut Ge (111) crystal monochromater. An imaging plate, which has a high detective quantum efficiency, a low quantization noise and a wide dynamic range is used as a 2-dimensional area detector. The sample position is slowly elevated to compensate for evaporation during measurements. A device for surface tension measurement by the ring method has been combined with the reflection apparatus so that in situ measurements may be possible. This system was tested by measuring X-ray reflectivity profiles from the free surface of water. We obtained a good agreement with the result reported by Braslau et al. (1985) who used synchrotron radiation. Several liquid alkanes and alcohols have been investigated and the reflectivity profiles have been interpreted in terms of a surface roughness characteristic of the size and shape of the molecules. In spite of using a conventional x-ray tube, the resolution in the momentum transfer of our reflection system is higher than that of synchrotron radiation system by Braslau et al..
  • (3)X線回折法によるナノ粒子分散液体の構造評価
  • (2)液体表面で探るタンパク質の立体構造形成機構
  • (1)超音波で発生した霧状液滴の研究
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