Details concernithe relationships between the structural, chemical and catalytic properties o MO nitrides have been elucidated. A series of MO nitride n! catalysts were prepared by the temperature programmed reaction of MoOa with NH3. The structural properties of these nitrides were complex functions

Effects of the synthesis parameters on the structural properties of molybdenum nitride catalysts, prepared by the temperatureprogrammed reaction of MoO3 with NH3, have been examined. Molybdenum trioxide was heated in flowing NH 3 through two linear heating segments (623 to 723 K then 723 to 973 K) with different space velocities in a 23 factorial design. The temperature limits for these heating segments were defined based on the results of in situ X-ray diffraction analysis of the gas-solid reaction. The resulting catalysts were characterized using BET surface area analysis, environmental scanning electron microscopy, ex situ X-ray diffraction, and oxygen chemisorption. The primary bulk phase present was y-Mo2N. Some of the lower surface area catalysts also contained MoO2 and Mo, but there was no evidence of nitrides other than y-Mo2N. The catalysts consisted of micrometersized, plate-like aggregates of nanometer-sized crystallites, and possessed surface areas ranging up to ~ 140 m2/g depending on the synthesis and reduction conditions employed. Statistical analysis of the results revealed that the space velocity individually and the heating rates combined had the most significant effects on the structural properties. The production of catalysts with surface areas in excess of 50 m2/g required the use of slow heating rates during the first segment and high space velocities. We concluded that the key to producing the highest surface area Mo nitrides was channeling the reaction through HxMoO3 (x-< 0.34) and ~,-Mo2OyNl-y intermediates. Passivation of the materials immediately following synthesis appeared to produce an oxynitride at the surface. Reduction of the passivated materials in H 2 at temperatures up to 673 K caused a significant increase in the surface area and O2 uptake. The 02 uptake for the low and medium surface area catalysts varied linearly with the BET surface area and corresponded to an O:Mo stoichiometry of approximately 1:5. The oxygen site density for the highest surface area nitride was lower than those for the lower surface area catalysts, presumably due to differing surface structures.

An ultrasmall single-electron transistor has been made by scaling the size of a fin field-effect transistor structure down to an ultimate limiting form, resulting in the reliable formation of a sub-5 nm Coulomb island. The charge stability data feature the first exhibition of three and a half clear Coulomb diamonds at 300 K, each showing a high peak-to-valley current ratio. Its charging energy is estimated to be more than one order magnitude larger than the thermal energy at room-temperature. The hybrid literal gate integrated by this single-electron transistor combined with a field-effect transistor displays >5 bit multiswitching behavior at 300 K with a large voltage swing of ～1 V

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We report on transport measurement performed on a room-temperature-operating ultra-small Coulomb blockade devices with a silicon island of sub-5nm. The charge stability at 300K exhibits a substantial change in slopes and diagonal size of each successive Coulomb diamond, but remarkably its main feature persists even at low temperature down to 5.3K except for additional Coulomb peak splitting. This key feature of charge stability with additional fine structures of Coulomb peaks are successfully modeled by including the interplay between Coulomb interaction, valley splitting, and strong quantum confinement, which leads to several low-energy many-body excited states for each dot occupancy. These excited states become enhanced in the sub-5nm ultra-small scale and persist even at 300K in the form of cluster, leading to the substantial modulation of charge stability.

The aim of our observational study was to investigate the clinical significance of interleukin (IL)-34, a novel osteoclastogenic cytokine, for predicting structural damage in patients with rheumatoid arthritis (RA). Serum IL-34 levels were measured in 100 RA patients, 36 patients with ankylosing spondylitis (AS), and 59 gender- and age-matched healthy individuals using an enzyme-linked immunosorbent assay. We also measured IL-34 concentrations in synovial fluid (SF) samples from 18 RA patients and 19 osteoarthritis (OA) patients. Progression of structural damage was assessed in 81 patients with RA by plain radiographs using the modified Sharp/van der Heijde score (SHS) at baseline and after an average 1.6-year follow-up period. Serum IL-34 levels were significantly higher in patients with RA (p < 0.001) or AS (p < 0.001) than in healthy controls. SF IL-34 levels were also significantly higher in RA patients than in OA patients (p < 0.001). In RA, serum IL-34 levels were associated with rheumatoid factor positivity (p = 0.01), current smoking (p < 0.01), erythrocyte sedimentation rate (p = 0.01), and C-reactive protein levels (p < 0.01), but not with disease activity score 28. ΔSHS/year was positively correlated with serum IL-34 levels (r = 0.443, p < 0.001). In multivariate logistic regression analyses, serum IL-34 level was an independent risk factor for radiographic progression. These results suggest that IL-34, a novel osteoclastogenic cytokine, plays a role in RA-associated joint damage and is a potential biomarker for predicting subsequent radiographic progression in patients with RA.

. Lightdirected electrical stimulation of neurons cultured on silicon wafers. J Neurophysiol 93: 1090 -1098, 2005. First published September 22, 2004 doi:10.1152/jn.00836.2004. Dissociated neurons cultured in vitro can serve as a model system for studying the dynamics of neural networks. Such studies depend on techniques for stimulating patterns of neural activity. We show a technique for extracellular stimulation of dissociated neurons cultured on silicon wafers. When the silicon surface is reverse biased, electrical current can be generated near any neuron by pulsing a laser. Complex spatiotemporal stimulation patterns can be produced by directing a single beam with an acousto-optic deflector. The technique can generate a stimulating current at any location in the culture. This contrasts with multielectrode arrays (MEAs), which can stimulate only at fixed electrode locations. To characterize reliability and spatial selectivity of stimulation, we used intracellular (patch-clamp) recordings to monitor the effect of targeted laser pulses on cultured hippocampal neurons. Action potentials could be stimulated with submillisecond precision and 100-micron spatial resolution at rates exceeding 100 Hz. Optimal control parameters for stimulation are discussed.

S-Methylmethionine sulfonium (SMMS) is a derivative of the amino acid methionine, and is synthesized in a variety of plants. SMMS is widely referred to as vitamin U because of its potent therapeutic effect on gastrointestinal ulceration. Skin wounds are accompanied by mucosal erosion and share similar histopathological aspects with gastric ulcers, so it is plausible that SMMS may promote skin wound healing. In animal models, topical administration of SMMS for a given period of time, to both physical and chemical wounds, facilitated wound closure and promoted re-epithelialization compared with a control. In addition, single SMMS treatment was sufficient to promote the growth of human dermal fibroblasts (hDFs) as well as the migration of hDFs, which are indispensable steps for skin wound healing. The promotion of hDF proliferation and migration resulted from considerable activation of ERK1/2 by SMMS, and inhibition of ERK activity by a chemical inhibitor significantly abrogated both the promoted proliferation and migration of hDFs. Therefore, we concluded that SMMS facilitated the repair process of skin damage by activation of dermal fibroblasts, which suggests that SMMS has potential as a skin wound-healing agent.