Pancreatic cancer intrinsic PI3Kα activity accelerates metastasis and rewires macrophage component.

Pancreatic ductal adenocarcinoma (PDAC) patients frequently suffer from undetected micro-metastatic disease. This clinical situation would greatly benefit from additional investigation. Therefore, we set out to identify key signalling events that drive metastatic evolution from the pancreas. We searched for a gene signature that discriminate localised PDAC from confirmed metastatic PDAC and devised a preclinical protocol using circulating cell-free DNA (cfDNA) as an early biomarker of micro-metastatic disease to validate the identification of key signalling events. An unbiased approach identified, amongst actionable markers of disease progression, the PI3K pathway and a distinctive PI3Kα activation signature as predictive of PDAC aggressiveness and prognosis. Pharmacological or tumour-restricted genetic PI3Kα-selective inhibition prevented macro-metastatic evolution by hindering tumoural cell migratory behaviour independently of genetic alterations. We found that PI3Kα inhibition altered the quantity and the species composition of the produced lipid second messenger PIP3 , with a selective decrease of C36:2 PI-3,4,5-P3 . Tumoural PI3Kα inactivation prevented the accumulation of pro-tumoural CD206-positive macrophages in the tumour-adjacent tissue. Tumour cell-intrinsic PI3Kα promotes pro-metastatic features that could be pharmacologically targeted to delay macro-metastatic evolution

Evidence of anti-coking behavior of La0.8Sr0.2Cr0.98Ru0.02O3 as potential anode material for Solid Oxide Fuel Cells directly fed under methane

+PDELa0.8Sr0.2CrO3 (LSC) based Ru catalysts are very active in methane steam reforming. Nevertheless, they can be easily poisoned under water-deficient conditions. Ru can be deposited as metallic ruthenium particles decorating the LSC grains or be inserted as Ru ions in the perovskite structure. Both Ru-promoted LSC catalysts were studied in methane steam reforming under water-deficient conditions and characterized after testing. Catalytic activity tests showed that ruthenium metal species are deactivated under water-deficient atmosphere, while ruthenium species inserted in LSC presented a remarkable stability and catalytic activity where residual steam plays a key role. Very unreactive carbon species responsible for deactivation were detected by temperature-programmed oxidation and transmission electron microscopy over metallic ruthenium species. Such species were not observed when ruthenium species are inserted and stabilized into the LSC structure. La0.8Sr0.2Cr0.98Ru0.02O3 appears therefore as a highly promising anti-coking anode material for Solid Oxide Fuel Cells directly fed with methane or natural gas and operating under water-deficient conditions. (c) 2012 Elsevier Inc. All rights reserved

Microstructure and thermoelectric properties of bulk and porous n-type silicon-germanium alloy prepared by HUP

The optimization of powders preparation and consolidation process leads to the achievement of a high thermoelectric figure of merit (ZT=1.25 at 800°C) in an n-type silicon-germanium (SiGe) alloy hot pressed at low heating rate. It has been experimentally observed that HUP compacting conditions can preserve nanostructuring. We also investigated the effect of porosity on the thermoelectric properties. Porous samples have enhanced Seebeck coefficients and low thermal conductivity. However, the figure of merit of the bulk specimen remains better than the porous samples due to a significant degradation of electrical conductivity. Working on grain boundaries engineering to enhance charge carriers mobility seems to be a promising way in addition to limiting nanograin growth with a densification process control. © 2012 American Institute of Physics

Reconstruction of the cubic and tetragonal oarent grains from electron backscatter diffraction maps of monoclinic zirconia

Monoclinic zirconia results from cubic→tetragonal→monoclinic phase transformations occurring at high temperature. Electron backscatter diffraction maps of monoclinic zirconia in fused-cast refractories have been treated with new crystallographic computer programs. The correct orientation relationships between the three phases have been identified among those proposed in the literature, the tetragonal and cubic parent grains have been automatically reconstructed, and the variants have been indexed. This example illustrates the possibilities of automatic crystallographic reconstruction software to study complex phase transition materials. © 2010 The American Ceramic Society

Catalytic steam reforming of methane over La0.8Sr0.2CrO3 based Ru catalysts

La0.8Sr0.2CrO3 based Ru catalysts were studied as potential new anodic materials for Solid Oxide Fuel Cells directly fed with methane and operating at intermediate temperature under water deficient conditions. Two kinds of materials very close in composition were obtained following two different preparation procedures. Catalyst samples were characterized by physicochemical methods (XRD, SEM, BET and Chemical Analysis) and studied in methane steam reforming under water deficient conditions. Carbon formation during catalytic testing was studied by temperature programmed oxidation (TPO). Both types of catalysts were found very active and resistant to carbon formation. The unusual oscillatory behavior of the catalytic activity observed for one type of catalyst was discussed. © 2007 Elsevier B.V. All rights reserved

Evidence of anti-coking behavior of La 0.8Sr 0.2Cr 0.98Ru 0.02O 3 as potential anode material for Solid Oxide Fuel Cells directly fed under methane

La 0.8Sr 0.2CrO 3 (LSC) based Ru catalysts are very active in methane steam reforming. Nevertheless, they can be easily poisoned under water-deficient conditions. Ru can be deposited as metallic ruthenium particles decorating the LSC grains or be inserted as Ru ions in the perovskite structure. Both Ru-promoted LSC catalysts were studied in methane steam reforming under water-deficient conditions and characterized after testing. Catalytic activity tests showed that ruthenium metal species are deactivated under water-deficient atmosphere, while ruthenium species inserted in LSC presented a remarkable stability and catalytic activity where residual steam plays a key role. Very unreactive carbon species responsible for deactivation were detected by temperature-programmed oxidation and transmission electron microscopy over metallic ruthenium species. Such species were not observed when ruthenium species are inserted and stabilized into the LSC structure. La 0.8Sr 0.2Cr 0.98Ru 0.02O 3 appears therefore as a highly promising anti-coking anode material for Solid Oxide Fuel Cells directly fed with methane or natural gas and operating under water-deficient conditions. © 2012 Elsevier Inc. All rights reserved

Microcracking of high zirconia refractories after t→m phase transition during cooling: An EBSD study

High zirconia refractories are composed of a zirconia skeleton surrounded by an intergranular glassy phase. In these materials, zirconia undergoes up to two successive phase transitions during the manufacturing process, c → t then t → m. This leads, after complete cooling, to the formation of microcracks. Preliminary observations have enabled to identify the mechanism mostly responsible for the observed microcracking. In particular, SEM imaging emphasizes the link between the positions of cracks and the presence of distinct crystallographic domains. Thus, our work focuses on the arrangement of the monoclinic and tetragonal domains in zirconia dendrites. The assessment by XRD of the thermal expansion coefficients of zirconia at the lattice scale and the analysis of EBSD maps show that cracking is produced by the thermal expansion mismatch between groups of crystallographic variants. The further reconstruction of both cubic and tetragonal - in the case of a presence of monoclinic zirconia at room temperature - parent grains enables to determine the impact of each transition on the final microstructure and the generated microcracking. © 2011 Elsevier Ltd