Mines ParisTech

About: Mines ParisTech is a education organization based out in Paris, France. It is known for research contribution in the topics: Finite element method & Microstructure. The organization has 6564 authors who have published 11676 publications receiving 359898 citations. The organization is also known as: École nationale supérieure des mines de Paris & École des mines de Paris.

A comprehensive modular map of molecular interactions in RB/E2F pathway

Abstract: We present, here, a detailed and curated map of molecular interactions taking place in the regulation of the cell cycle by the retinoblastoma protein (RB/RB1). Deregulations and/or mutations in this pathway are observed in most human cancers. The map was created using Systems Biology Graphical Notation language with the help of CellDesigner 3.5 software and converted into BioPAX 2.0 pathway description format. In the current state the map contains 78 proteins, 176 genes, 99 protein complexes, 208 distinct chemical species and 165 chemical reactions. Overall, the map recapitulates biological facts from approximately 350 publications annotated in the diagram. The network contains more details about RB/E2F interaction network than existing large-scale pathway databases. Structural analysis of the interaction network revealed a modular organization of the network, which was used to elaborate a more summarized, higher-level representation of RB/E2F network. The simplification of complex networks opens the road for creating realistic computational models of this regulatory pathway.

The colour of ochres explained by their composition

Abstract: The first purpose of this paper is to underline a relevant colorimetric co-ordinate characterizing the colour of ochres within their extremely wide range, from pale yellow to dark red. The second purpose is to link together quantitatively the variations of this colorimetric co-ordinate and the various chemical compositions of the samples, mainly hematite, goethite and white pigments. A group of 30 modern ochres and a group of 20 ancient ochres have been investigated. All these natural pigments have been commercialized. Diffuse reflectance spectrometry allows to calculate the colorimetric co-ordinates in the CIE-L*a*b* space and the position of the absorption band of each sample. Physico-chemical analysis has been obtained by quantitative X-ray diffraction, scanning and transmitting electronic microscopy and particle-size analysis by laser diffraction. The positive a* co-ordinate (redness) has been underlined, for the first time, to be the only relevant colorimetric parameter to characterize the colour of the ochres. Its variations are quantitatively connected to the shift of the absorption band due to the charge transfer between the ligand (OH− or O2−) and the Fe3+ ion contained in goethite and/or hematite. For ochres containing both hematite and goethite, the a* co-ordinate linearly increases with the relative amount of hematite while the absorption band progressively shifts towards the high wavelengths. Such a linear shift of the absorption band has never been underlined before. For ochres containing only one iron oxide, a* linearly decreases with the amount of white pigments, whatever the nature of the white charges. Moreover, this study gives the opportunity to show that only the nature, the amount and the size distribution of the white charges allow to discriminate the ochres according to their geographic origin.

Low-pressure, high-density plasma nitriding: mechanisms, technology and results

Abstract: This paper reviews the low-pressure (<10 Pa), high-density plasma-assisted nitriding processes recently developed for metallurgical surface modification to improve wear, hardness and fatigue resistance of ferrous and non-ferrous materials. For that purpose, plasma generation is most frequently ensured by d.c. glow discharges at relatively high pressure (100–1000 Pa) with the underlying limitations associated with this technology. Nevertheless, more flexibility and control are required for plasma nitriding of promising non-ferrous materials such as titanium, aluminium and their alloys. These requirements are fulfilled by the recently developed enhanced or intensified plasma nitriding processes that operate at lower pressures (<10 Pa) such as: thermionically assisted d.c. triode arrangements (TAT), plasma immersion ion implantation (PIII) or plasma source ion implantation (PSII), electron cyclotron resonance (ECR) systems and thermionic arc discharges (TAD). The purpose of this paper is to review these new nitriding processes from both technological and fundamental points of view. Plasma parameters and plasma–surface interactions are considered for these processes.

Phase Equilibria of Methane and Carbon Dioxide Clathrate Hydrates in the Presence of Aqueous Solutions of Tributylmethylphosphonium Methylsulfate Ionic Liquid

Abstract: The effect of a tributylmethylphosphonium methylsulfate ionic liquid (IL) aqueous solution on the equilibrium conditions of carbon dioxide and methane clathrate hydrates was studied. An isochoric pressure-search method was used to measure the hydrate dissociation conditions for the carbon dioxide + tributylmethylphosphonium methylsulfate + water and methane + tributylmethylphosphonium methylsulfate + water systems in the temperature ranges of (273.5 to 282.2) K and (273.3 to 288.5) K, and pressures up to (4.35 and 14.77) MPa, respectively. The concentrations of tributylmethylphosphonium methylsulfate in the aqueous solutions were 0, 0.2611, and 0.5007 mass fractions. The good agreement between our experimental hydrate dissociation data in the absence of tributylmethylphosphonium methylsulfate with selected literature experimental data demonstrates the reliability of the experimental method used in this work. The comparison between the hydrate dissociation conditions in the presence and absence of tributyl...