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.

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

Fujiwara, Satoru*; Kono, Fumiaki*; Matsuo, Tatsuhito*; Sugimoto, Yasunobu*; Matsumoto, Tomoharu*; Narita, Tetsuhiro*; Shibata, Kaoru

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

https://doi.org/10.1016/j.jmb.2019.05.047

-synuclein (Syn) is an intrinsically disordered protein (IDP) with unknown function. Syn is known to form amyloid fibrils, which are implicated with the pathogenesis of Parkinson's disease and other synucleinopathies. Elucidating the mechanism of fibril formation of Syn is therefore important for understanding the mechanism of the pathogenesis of these diseases. Here, using the quasielastic neutron scattering (QENS) and small-angle X-ray scattering (SAXS) techniques, we investigated the dynamic and structural properties of Syn. These results imply that fibril formation of Syn requires not only the enhanced local motions but also the segmental motions such that the proper inter-molecular interactions are possible.

A New high-resolution small-angle X-ray scattering apparatus using a fine-focus rotating anode,point-focusing collimation and a position-sensitive proportional counter

Journal of Applied Crystallography, 17, p.337 - 343, 1984/00

https://doi.org/10.1107/S0021889884011614

no abstracts in English

Quantifying isolated pore space in geological barrier materials

Hu, Q.*; Wang, Q.*; Oware, P.*; Tachi, Yukio; Fukatsu, Yuta; Ilavsky, J.*; Almer, J.*

no journal, ,