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Acta Cryst. (2014). A70, C360
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"To improve performance of hydrogen storage materials, it is essential to understand detailed mechanism of hydrogenation and dehydrogenation reactions. In-situ powder diffraction measurements provide direct information about structural changes accompanying the reactions. We therefore installed a time-resolved x-ray diffraction (XRD) system at a beamline BL22XU at the SPrign-8, a synchrotron radiation facility in Japan. The system was equipped with two area detectors, a flat panel sensor for precise structural analyses and a high speed video camera connected to an x-ray image intensifier for observation of rapid phase changes. Maximum frame rate for the flat panel sensor and high-speed video camera was 2 fps and 125 fps (effective), respectively. A sample cell was connected to a hydrogen supply system. Opening of upstream valve of the sample cell or a change of the pressure at the sample triggered the recording of the diffraction patterns. The pressure of hydrogen gas was limited to 1 MPa. To demonstrate the performance of the system, we have performed time-resolved XRD experiments for LaNi4.5Al0.5. LaNi5 exhibits the significant broadening of the diffraction peaks by hydrogen absorption; however, LaNi4.5Al0.5 shows the no significant broadening. We have succeeded in the measurements of the structural change from the solid solution phase to the hydride phase and have found the formation of the transient intermediate phase on this reaction process. The system is currently used to study several materials. This work was partly supported by New Energy and Industrial Technology Development Organization (NEDO) under ""Advanced Fundamental Research Project on Hydrogen Storage Materials""."

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Acta Cryst. (2014). A70, C860
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Numerous energy materials with improved properties often show nano- or heavily disordered structural features which are hardly characterized by the conventional crystallographic technique alone. By using the atomic pair distribution function (PDF) analysis [1]on X-ray and neutron total scattering data, we have investigated various energy materials to elucidate structural features closely linked to their properties. Some of the examples are heavily disordered V1-xTixH2 for hydrogen storage [2] and layered Li1.2Mn0.567Ni0.166Co0.067O2 cathode material for lithium ion batteries. These materials possess an intricate structure and could easily lead to misleading results if one relies on only one structure probing technique. In this talk, I will show how their structural information was extracted from the x-ray and neutron PDFs obtained at BL22XU at SPring-8 and NOVA at J-PARC, respectively and how it was used with information available from other techniques to understand the properties of these energy materials.

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Acta Cryst. (2014). A70, C868
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Hydrogen has been considered as a promising alternative fuel for transportation, provided we can find a way to store a large amount of hydrogen in a compact way. The realization of such a storage system can be achieved by developing materials that can easily absorb, safely store, and rapidly release hydrogen repeatedly. However, there is currently no material to meet all the requirements for on board storage. Great efforts have been made to understand hydrogenation properties of currently available materials to look for a way to improve properties or to prepare new materials. However, investigating the structure of some of these materials is challenging since their hydrides are only available under hydrogen gas pressure. Furthermore, many novel materials with improved properties often show heavily disordered or nanoscale structural features which are difficult to characterize using conventional crystallographic technique alone (crystallographically challenged hydrogen storage materials). In order to investigate the structural change in crystallographically challenged hydrogen storage materials during hydrogenation or dehydrogenation processes we have developed in-situ hydrogen gas loading setup for synchrotron X-ray total scattering experiments at the Japan Atomic Energy Agency (JAEA) beamline of BL22XU [1] at SPring-8. Coupled to an area detector [1,2], this setup allows us to obtain the atomic pair distribution function (PDF) [3] of metal hydrides either in equilibrium or in non-equilibrium state with hydrogen. In this poster, we will introduce our in-situ setup and present some preliminary results on AB5-type intermetallic compounds and Pd nanoparticles.

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Acta Cryst. (2014). A70, C1493
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"We present the crystal structure of AcrB in complex with Linezolid[1]. AcrB is an inner-membrane Resistance-Nodulation-Division efflux pump and is part of the AcrAB-TolC multidrug-resistance tripartite efflux system in E. Coli. Crystal structures of AcrB by itself as well as several drug-bound complexes have been structurally characterized. Linezolid is an approved oxazolidinone antibiotic used for the treatment of serious infections caused by Gram-positive bacteria that are resistant to other antibiotics, and has been called a ""reserve antibiotic"", a drug of last resort against potentially intractable infections. This antibiotic inhibits bacterial protein synthesis by specifically binding to the 50S ribosomal subunit. Linezolid has no clinically significant effect on most Gram-negative bacteria. This is thought to be a result of relatively low intracellular concentration of Linezolid due to efflux, but there is no direct evidence yet to support this hypothesis. This membrane protein-drug complex shows that an antibiotic specific to Gram-positive bacteria can also bind an efflux pump from E. coli, a Gram-negative bacterium. The crystal structure of AcrB and Linezolid complex reveals that Linezolid binds to the A385/F386 loops of the symmetric trimers of AcrB in the same fashion as several other antibiotics that are extruded by efflux pumps. A conformational change of a loop in the bottom of the periplasmic cleft is also observed."

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Acta Cryst. (2014). A70, C1509
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The DJ-1/ThiJ/PfpI superfamily is a large protein group over diverse organisms, under this superfamily, there are multi-types of proteins such as protease, chaperones, heat shock protein, human parkinson's disease protein. The conserved protein from Staphylococcus aureus SAV1875 is a member of DJ-1 superfamily, but its function is unknown. We have determined the crystal structure of SAV1875 to a resolution of 1.8Å . As expected, the overall fold of the core domain of SAV1875 is similar to that of DJ-1. SAV1875 appears to be a dimer both in solution and the crystal, displaying an oligomerization interface similar to that observed for DJ-1. SAV 1875 contains a possible catalytic triad (Cys105-Glu17-His106) analogous to PfpI, YhbO, and DR1199. The cysteine in this triad (Cys-105) is oxidized in this crystal structure, similar to modifications seen in the cysteine of the DJ-1. This Cys-sulfenic acid is stabilized by hydrogen bonding with Glu17, Gly72, His106. We also have determined the crystal structure of mutated form of reactive Cys, SAV1875 C105D to a resolution of 2.1 Å. Aspartate mutation mimics the the Cys-sulfinic acid, more oxidized form. The aspartate stabilization by hydrogen bonding with neighboring residues are maintained. On the basis of these results, we suggest that SAV1875 might work as a general stress protein involved in the detoxification of the cell from oxygen reactive species.
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