Organization of malonamides from the interface to the organic bulk phase

Micheau, C.; Ueda, Yuki; Motokawa, Ryuhei; Akutsu, Kazuhiro*; Yamada, Norifumi*; Yamada, Masako*; Moussaoui, S. A.*; Makombe, E.*; Meyer, D.*; Berthon, L.*; et al.

Journal of Molecular Liquids, 401, p.124372_1 - 124372_12, 2024/05

https://doi.org/10.1016/j.molliq.2024.124372

Supramolecular organization of extractant molecules impacts metal ions separation behavior. Probing bulk and interfacial structures of the relevant systems is expected to provide key insights into the metal ion selectivity and kinetic aspects. The supramolecular features of two solvent extraction systems based on malonamide extractants THMA in toluene and DBMA in n-heptane were studied using small-angle X-ray scattering for the organic bulk phases, as well as interfacial tension and neutron reflectivity measurements for the interfaces. In the bulk solution, THMA forms dimeric/trimeric associates but no aggregates in toluene, while DBMA forms large aggregates in n-heptane. On the other hand, THMA accumulates in a diffuse layer at the interface at high THMA concentration, whereas DBMA forms a compact but thinner layer. After Pd(II) extraction, the thickness of interfacial layers decreases in the case of THMA, and totally vanishes in the case of DBMA. Based on these new structural information, two mechanisms are proposed for Pd(II) and Nd(III) extraction with malonamides. In toluene, THMA associates slightly accumulate in the vicinity of the interface, then coordinate Pd(II) and diffuse into the organic bulk phase. In n-heptane, DBMA aggregates adsorb at the interface then pick up Nd(III) cations in their polar cores and finally diffuse into the bulk.

Micro- to nano-scale areal heterogeneity in pore structure and mineral compositions of a sub-decimeter-sized Eagle Ford Shale

Wang, Q.*; Hu, Q.*; Zhao, C.*; Yang, X.*; Zhang, T.*; Ilavsky, J.*; Kuzmenko, I.*; Ma, B.*; Tachi, Yukio

International Journal of Coal Geology, 261, p.104093_1 - 104093_15, 2022/09

https://doi.org/10.1016/j.coal.2022.104093

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

Fujiwara, Satoru*; Matsuo, Tatsuhito*; Sugimoto, Yasunobu*; Shibata, Kaoru

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

https://doi.org/10.1021/acs.jpclett.9b03196

Characterization of the dynamics of disordered polypeptide chains is required to elucidate the behavior of intrinsically disordered proteins and proteins under non-native states related to the folding process. Here we develop a method using quasielastic neutron scattering, combined with small-angle X-ray scattering and dynamic light scattering, to evaluate segmental motions of proteins as well as diffusion of the entire molecules and local side-chain motions. We apply this method to RNase A under the unfolded and molten-globule (MG) states. The diffusion coefficients arising from the segmental motions are evaluated and found to be different between the unfolded and MG states. The values obtained here are consistent with those obtained using the fluorescence-based techniques. These results demonstrate not only feasibility of this method but also usefulness to characterize the behavior of proteins under various disordered states.

Thermal behavior, structure, dynamic properties of aqueous glycine solutions confined in mesoporous silica MCM-41 investigated by X-ray diffraction and quasi-elastic neutron scattering

Yoshida, Koji*; Inoue, Takuya*; Torigoe, Motokatsu*; Yamada, Takeshi*; Shibata, Kaoru; Yamaguchi, Toshio*

Journal of Chemical Physics, 149(12), p.124502_1 - 124502_10, 2018/09

https://doi.org/10.1063/1.5039892

Differential scanning calorimetry, X-ray diffraction, and quasi-elastic neutron scattering (QENS) measurements of aqueous glycine solutions confined in mesoporous silica (MCM-41) were performed at different glycine concentrations, pH, and loading ratio (= mass of glycine solution / mass of dry MCM-41) in the temperature range from 305 to 180 K to discuss the confinement effect on the thermal behavior, the structure, and the dynamic properties of the solutions.

Impurity effects in the microscopic elastic properties of polycrystalline Mg-Zn-Y alloys with a synchronised long-period stacking ordered phase

Hosokawa, Shinya*; Kimura, Koji*; Yamasaki, Michiaki*; Kawamura, Yoshihito*; Yoshida, Koji*; Inui, Masanori*; Tsutsui, Satoshi*; Baron, A. Q. R.*; Kawakita, Yukinobu; Ito, Shinichi*

Journal of Alloys and Compounds, 695, p.426 - 432, 2017/02

https://doi.org/10.1016/j.jallcom.2016.10.266

Structural aspects of the superionic conduction mechanism in Ag-GeSe glasses

Stellhorn, J. R.*; Hosokawa, Shinya*; Pilgrim, W.-C.*; Kawakita, Yukinobu; Kamimura, Kenji*; Kimura, Koji*; Blanc, N.*; Boudet, N.*

Zeitschrift fr Physikalische Chemie, 230(3), p.369 - 386, 2016/03

https://doi.org/10.1515/zpch-2015-0667

Momentum dependence of Mott gap excitations in optimally doped YBaCuO studied by resonant inelastic X-ray scattering

Ishii, Kenji; Tsutsui, Kenji*; Endo, Yasuo*; Toyama, Takami*; Kuzushita, Kaori; Inami, Toshiya; Owada, Kenji; Maekawa, Sadamichi*; Masui, Takahiko*; Tajima, Setsuko*; et al.

AIP Conference Proceedings 850, p.445 - 446, 2006/09

https://doi.org/10.1063/1.2354776

Mott gap excitations in the optimally doped high- superconductor YBaCuO ( = 93 K) have been studied by the resonant inelastic X-ray scattering method. Anisotropic spectra in the -plane are observed in a twin-free crystal. The excitation from the one-dimensional CuO chain is enhanced at 2 eV near the zone boundary of the direction, while the excitation from the CuO plane is broad at 1.5-4 eV and almost independent of the momentum transfer. Theoretical calculation based on the one-dimensional and two-dimensional Hubbard model reproduces the observed spectra when different values of the on-site Coulomb energy are assumed. The Mott gap of the CuO chain site is found to be much smaller than that of the CuO plane site.

Resonant magnetic X-ray scattering study of UPdAl

Ishii, Kenji; Kuzushita, Kaori; Murakami, Yoichi; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika

Journal of the Physical Society of Japan, 75(Suppl.), p.102 - 104, 2006/08

UPdAl is an attractive material because of the coexistence of the antiferromagnetic order below = 14.5 K and superconductivity below = 2 K. In order to discuss the coupling between magnetism and superconductivity by resonant magnetic X-ray scattering (RMXS), nature of the resonance at each absorption edge should be clarified before the measurements across . Therefore we performed RMXS study from U to edge at . In addition to a huge resonance at -edge, we observed a resonant feature at -edge which corresponds to the transition from to orbitals, while resonance at -edge and -edge is rather small.

Momentum dependence of charge excitations in the electron-doped superconductor NdCeCuO; A Resonant inelastic X-ray scattering study

Ishii, Kenji; Tsutsui, Kenji*; Endo, Yasuo*; Toyama, Takami*; Maekawa, Sadamichi*; Hoesch, M.; Kuzushita, Kaori; Tsubota, Masami; Inami, Toshiya; Mizuki, Junichiro; et al.

Physical Review Letters, 94(20), p.207003_1 - 207003_4, 2005/05

https://doi.org/10.1103/PhysRevLett.94.207003

We report a resonant inelastic X-ray scattering (RIXS) study of charge excitations in the electron-doped high- superconductor NdCeCuO. The intraband and interband excitations across the Fermi energy are separated for the first time by tuning the experimental conditions properly to measure charge excitations at low energy. A dispersion relation with -dependent width emerges clearly in the intraband excitation, while the intensity of the interband excitation is concentrated around 2 eV near the zone center. The experimental results are consistent with theoretical calculation of the RIXS spectra based on the Hubbard model.

Charge-order pattern of the low-temperature phase from a monoclinic single domain of NaVO uniquely determined by resonant X-ray scattering

Owada, Kenji; Fujii, Yasuhiko; Katsuki, Yuya*; Muraoka, Jiro*; Nakao, Hironori*; Murakami, Yoichi; Sawa, Hiroshi*; Ninomiya, Emi*; Isobe, Masahiko*; Ueda, Yutaka*

Physical Review Letters, 94(10), p.106401_1 - 106401_4, 2005/03

https://doi.org/10.1103/PhysRevLett.94.106401

The present resonant X-ray scattering has been performed on a monoclinically-split single domain of NaVO. The observation of a critically enhanced contrast between V and V ions has led us to the unequivocal conclusion of the charge-order pattern of low-temperature phase of NaVO below = 35 K. In spite of the possible four types of configuration of the zig-zag-type charge-order patterns in the -plane (A, A', B and B'), the stacking sequence along the -axis is determined as the AAA'A' type by comparison with model calculations. By assigning the A and A' configurations to Ising spins, one can reasonably explain the previously discovered "devil's staircase"-type behavior with respect to the modulation of layer-stacking sequences at high pressures and low temperatures, which clearly resembles the global phase diagram theoretically predicted by the ANNNI model.