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A two-phase nanocomposite coating that consists of inclusions of silver in a vanadium nitride matrix (VN/Ag) was investigated as a potential adaptive coating with a reduced friction coefficient from 25 to 1000 °C. This nanocomposite structure was selected based on the premise that silver and silver vanadate phases would form on the surface of these coatings, reducing their friction coefficient in the (i) room to mid-range and (ii) mid-range to high temperatures, respectively. Silver and vanadium were expected to react with oxygen at high temperatures and create a lubricious silver vanadate film on the coating. The VN/Ag coatings were deposited using unbalanced magnetron sputtering and their elemental composition was evaluated using X-ray photoelectron spectroscopy. The tribological properties of the materials against Si 3N4 balls were investigated at different temperatures. The lowest friction coefficients recorded for samples with identical compositions were 0.35, 0.30, 0.10 and 0.20 at 25, 350, 700 and 1000 °C, respectively. Post-wear testing Raman spectroscopy and X-ray diffraction (XRD) measurements revealed the formation of silver vanadate compounds on the surface of these coatings. In addition, real time Raman spectroscopy and high temperature XRD revealed that silver vanadate, vanadium oxide and elemental silver formed on the surface of these coatings upon heating to 1000 °C. Upon cooling, silver and vanadium oxide were found to combine at about 400 °C, leading predominantly to the formation of silver vanadate phases on the surface of these materials. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. 58 5326 5331 5326-5331

In this work, we explore the thermal properties of hexagonal transition metal dichalcogenide compounds with different average atomic masses but equivalent microstructures. Thermal conductivity values of sputtered thin films were compared to bulk crystals. The comparison revealed a > 10 fold reduction in thin film thermal conductivity. Structural analysis of the films revealed a turbostratic structure with domain sizes on the order of 5-10 nm. Estimates of phonon scattering lengths at domain boundaries based on computationally derived group velocities were consistent with the observed film microstructure, and accounted for the reduction in thermal conductivity compared to values for bulk crystals. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4793203]

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Double oxide phases combining a transition metal and a noble metal have recently become a subject of investigation as solid lubricant materials for high-temperature tribological applications. Here, we study the changes in chemistry and crystal structure of silver molybdate (Ag2Mo2O7) and silver tungstate (Ag2WO4) thin films and powders from 25 to 600°C. We show, using ab initio molecular dynamics, high-temperature X-ray diffraction, high-temperature Raman spectroscopy and differential scanning calorimetry in combination with sliding tests, that the layered atomic structure of silver molybdate facilitates sliding, resulting in a low coefficient of friction (

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519 1489 1489 1489-1489

Non-alcoholic fatty liver disease is the clinical hepatic expression of metabolic syndrome. The prevalence of non-alcoholic fatty liver disease is around 20-30%, and with a rapid increase in the metabolic risk factors in the general population, non-alcoholic fatty liver disease has become the most common cause of liver disease worldwide. A fraction (20-30%) of non-alcoholic fatty liver disease patients develop a potentially progressive hepatic disorder, namely non-alcoholic steatohepatitis, leading to end-stage liver disease. The pathogenesis of non-alcoholic fatty liver disease is not entirely understood, and even if insulin resistance is a major pathogenetic key, many other factors are implicated in both liver fat accumulation and disease progression to non-alcoholic steatohepatitis. In this review we aim to examine the literature, principally concerning human non-alcoholic fatty liver disease pathogenesis, and to identify the newest, most promising clinical and basic research data.