University of Tsukuba

About: University of Tsukuba is a education organization based out in Tsukuba, Ibaraki, Japan. It is known for research contribution in the topics: Population & Gene. The organization has 36352 authors who have published 79483 publications receiving 1934752 citations. The organization is also known as: Tsukuba daigaku & Tsukuba University.

Reaction mechanism of the glycerol hydrogenolysis to 1,3-propanediol over Ir-ReOx/SiO2 catalyst

Abstract: The mechanism of the hydrogenolysis of glycerol to 1,3-propanediol over Ir–ReOx/SiO2 catalyst was discussed. We investigated the catalytic performance, structure, reaction kinetics and reactivity trends of various substrates over the catalysts with different amount of Re. The conversion in the glycerol hydrogenolysis increased with increasing the amount of Re up to Re/Ir = 2, and the high selectivity to 1,3-propanediol (ca. 60%) was almost independent of the Re amount. The average size of Ir metal particle gradually decreased with increasing the amount of Re from XRD and TEM. Characterization results such as CO adsorption, TPR, XANES, EXAFS suggested that Ir metal surface was partially covered with ReOx cluster regardless of the Re amount. The reaction order on H2 pressure over Ir–ReOx/SiO2 (Re/Ir = 1) was one, suggesting that one active hydrogen species was produced from one hydrogen molecule. Low reaction order on glycerol concentration represented the strong interaction between glycerol and catalyst surface. This catalyst is also applicable to the selective hydrogenolysis of the C–O bond neighboring a –CH2OH group. These reaction trends and characterization results supported the direct reaction mechanism for the formation of 1,3-propanediol from glycerol via 2,3-dihydroxypropoxide species.

Distinct contribution of IL-6, TNF-α, IL-1, and IL-10 to T cell-mediated spontaneous autoimmune arthritis in mice

Abstract: Cytokines play key roles in spontaneous CD4(+) T cell-mediated chronic autoimmune arthritis in SKG mice, a new model of rheumatoid arthritis. Genetic deficiency in IL-6 completely suppressed the development of arthritis in SKG mice, irrespective of the persistence of circulating rheumatoid factor. Either IL-1 or TNF-alpha deficiency retarded the onset of arthritis and substantially reduced its incidence and severity. IL-10 deficiency, on the other hand, exacerbated disease, whereas IL-4 or IFN-gamma deficiency did not alter the disease course. Synovial fluid of arthritic SKG mice contained high amounts of IL-6, TNF-alpha, and IL-1, in accord with active transcription of these cytokine genes in the afflicted joints. Notably, immunohistochemistry revealed that distinct subsets of synovial cells produced different cytokines in the inflamed synovium: the superficial synovial lining cells mainly produced IL-1 and TNF-alpha, whereas scattered subsynovial cells produced IL-6. Thus, IL-6, IL-1, TNF-alpha, and IL-10 play distinct roles in the development of SKG arthritis; arthritogenic CD4(+) T cells are not required to skew to either Th1 or Th2; and the appearance of rheumatoid factor is independent of joint inflammation. The results also indicate that targeting not only each cytokine but also each cell population secreting distinct cytokines could be an effective treatment of rheumatoid arthritis.

Atomistic Origins of High Rate Capability and Capacity of N-Doped Graphene for Lithium Storage

Abstract: Distinct from pure graphene, N-doped graphene (GN) has been found to possess high rate capability and capacity for lithium storage. However, there has still been a lack of direct experimental evidence and fundamental understanding of the storage mechanisms at the atomic scale, which may shed a new light on the reasons of the ultrafast lithium storage property and high capacity for GN. Here we report on the atomistic insights of the GN energy storage as revealed by in situ transmission electron microscopy (TEM). The lithiation process on edges and basal planes is directly visualized, the pyrrolic N "hole" defect and the perturbed solid-electrolyte-interface configurations are observed, and charge transfer states for three N-existing forms are also investigated. In situ high-resolution TEM experiments together with theoretical calculations provide a solid evidence that enlarged edge {0002} spacings and surface hole defects result in improved surface capacitive effects and thus high rate capability and the high capacity are owing to short-distance orderings at the edges during discharging and numerous surface defects; the phenomena cannot be understood previously by standard electron or X-ray diffraction analyses.