Article: In Vitro Biomineralization and Bulk Characterization of Chitosan/Hydroxyapatite Composite Microparticles Prepared by Emulsification Cross-Linking Method: Orthopedic Use.[show abstract] [hide abstract]
ABSTRACT: Chitosan/hydroxyapatite composite microparticles were prepared by a solid-in-water-in-oil emulsification cross-linking method. The characteristics and activity in presence of simulated body fluid for 14 and 21 days were investigated. The size distribution, surface morphology, and microstructure of these biomaterials were evaluated. The scanning electron microscopy revealed an aggregate of microparticles with a particle size, ranged from 4 to 10 μm. The deposited calcium phosphate was studied using X-ray diffraction analysis, Fourier transform infrared spectroscopy, and inductively coupled plasma/atomic emission spectroscopy analysis of phosphorus. These results show that the mineral, formed on microparticles, was a mixture of carbonated hydroxyapatite and calcite. Scanning electron microscopy revealed that calcium phosphate crystals growth was in form of rods organized as concentric triangular packets interconnected to each other by junctions. Interaction between chitosan and growing carbonated hydroxyapatite and calcite crystals are responsible for a composite growth into triangular and spherical shapes. The results demonstrated that these microparticles were potential materials for bone repair.Applied biochemistry and biotechnology 09/2012; · 1.94 Impact Factor
Article: Rheological behaviour of binary mixtures containing hexyl(tetradecyl)phosphonium chloride (Cyphos IL 101) and bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) between 288.15 K and 343.15 KDiana Cholico-Gonzalez, Mario Avila-Rodriguez, J Antonio Reyes-Aguilera, Gerard Cote, Alexandre Chagnes[show abstract] [hide abstract]
ABSTRACT: Variation of the viscosity as a function of temperature and composition in Cyanex 272-Cyphos IL 101 binary mixtures has been investigated between 288.15 K and 343.15 K in the whole range of mole fraction. Valuable information regarding intermolecular interactions between Cyanex 272 and Cyphos IL 101 has been deduced from viscosity data by calculating excess viscosities, activation enthalpies and entropies and ion contributions to the activation energy and the activation entropy for the viscous flow. Peculiarly Cyphos IL 101 and Cyanex 272 exist as contact ion-pairs and ion-pairs separated by hydrochloride molecule depending on the mole fraction of Cyphos IL 101 in the binary mixture. (C) 2012 Elsevier B.V. All rights reserved.Journal of Molecular Liquids 05/2012; 169:27-32. · 1.58 Impact Factor
Alexandre Chagnes, Jolanta Swiatowska02/2012; , ISBN: 978-953-51-0077-5
Article: INFLUENCE OF PHASE MODIFIERS ON THE DEGRADATION OF TRI-N-OCTYLAMINE/DODECANE EXTRACTING MIXTURE BY AN ACIDIC SOLUTION OF VANADIUM (V)[show abstract] [hide abstract]
ABSTRACT: The kinetics of degradation of a mixture of tri-n-octylamine (extractant) and various alcoholic phase modifiers in n-dodecane in contact with acidic aqueous sulfate solutions containing vanadium (V) has been investigated. The nature of the modifier influences the kinetics of degradation and an improvement of the resistance against the chemical degradation is obtained when secondary alcohol (2-nonanol) or tertiary alcohols such as 9-octyl-9-heptadecanol are used as phase modifiers instead of 1-tridecanol. For instance, the kinetic constant of degradation is divided by one half when 9-octyl-9-heptadecanol is used as phase modifier instead of 1-tridecanol. On the contrary, the alcohols containing aromatic substituents or fluorine atoms are responsible for an increase of the chemical degradation of the extraction solvent.Solvent Extraction and Ion Exchange 01/2012; 30(1):67-76. · 2.02 Impact Factor
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ABSTRACT: Density functional theory calculations were performed on uranyl complexed with nitrate and monoamide ligands (L) [UO(2)(NO(3))(2)·2L]. The obtained results show that the complex stability is mainly governed by two factors: (i) the maximization of the polarizability of the coordinating ligand and (ii) the minimization of the steric hindrance effects. Furthermore, the electrostatic interaction between ligands and uranium(vi) was found to be a crucial parameter for the complex stability. These results pave the way to the definition of (quantitative) property/structure relationships for the in silico screening of monoamide ligands with improved extraction efficiency of uranium(vi) in nitrate acidic solution.Physical Chemistry Chemical Physics 09/2011; 13(43):19371-7. · 3.57 Impact Factor
Associate Professor at Ecole Nationale Supérieure de Chimie de Paris (ENSCP, Chimie Paristech) and scientific consultant , my research is focused on the comprehension of physicochemical and electrochemical phenomena involved in hydrometallurgical processes and lithium-ion batteries in order to improve the efficiency of processes or to develop new processes.
I am author of 41 papers in international journals, 3 chapters of books, 1 book and 43 presentation in international conferences.