Synthèse par dépôt chimique en phase vapeur catalytique (C-CVD) de nanostructures de carbone et leurs applications en catalyse et pour des matériaux composites

Dans ce travail, nous décrivons les différentes formes, la structure, les propriétés et la croissance catalytique de nanotubes et nanofibres de carbone (Chapitre I). L'hydroxyapatite a été utilisée comme support de la phase active pour la synthèse de nanotubes de carbone multi-feuillet (MWCNTs) et de nanofibres de carbone (CNFs-H) par la technique de dépôt chimique en phase de vapeur catalytique (C-CVD) en lit fluidisé (Chapitre II). Après l'élimination du support par un simple lavage à l'acide chloridrique dilué, une étude théorique et expérimentale de l'oxydation de la surface de nanotubes de carbone par un traitement à l'acide nitrique a permis d'une part d'identifier et de quantifier les groupes formés à la surface de nanostructures carbonées et d'autre part de proposer un mécanisme pour la formation de ces groupes (Chapitre III). Les matériaux résultants après génération des fonctions carboxyliques de surface ont été utilisés comme support de catalyseur. L'hydrogénation du p-halogénonitrobenzène a été choisit comme réaction modèle pour comparer les performances catalytiques de catalyseurs à base de ruthénium en fonction de la nature du support utilisé, MWCNTs ou CNFs-H. L'influence de certains paramètres tels que la température, la nature du substrat et un traitement thermique du catalyseur (activation) est présentée. Une explication des performances catalytiques est proposée après caractérisation du catalyseur par MET, TPD, TPR et PZC (Chapitre IV). Les nanostructures carbonnées produites et caractérisées ont été utilisées comme charge de renforcement d'hydroxyapatites connue comme biomatériaux. Nous avons étudié en particulier la capacité de germination du phosphate octocalcique par la méthode de croissance cristalline à composition constante (C4) (Chapitre V)

Synthesis of carbon nanostructures by Catalytic chemical vapor deposition : Application in catalysis and in composite materials

Dans ce travail, nous décrivons les différentes formes, la structure, les propriétés et la croissance catalytique de nanotubes et nanofibres de carbone (Chapitre I). L'hydroxyapatite a été utilisée comme support de la phase active pour la synthèse de nanotubes de carbone multi-feuillet (MWCNTs) et de nanofibres de carbone (CNFs-H) par la technique de dépôt chimique en phase de vapeur catalytique (C-CVD) en lit fluidisé (Chapitre II). Après l'élimination du support par un simple lavage à l'acide chloridrique dilué, une étude théorique et expérimentale de l'oxydation de la surface de nanotubes de carbone par un traitement à l'acide nitrique a permis d'une part d'identifier et de quantifier les groupes formés à la surface de nanostructures carbonées et d'autre part de proposer un mécanisme pour la formation de ces groupes (Chapitre III). Les matériaux résultants après génération des fonctions carboxyliques de surface ont été utilisés comme support de catalyseur. L'hydrogénation du p-halogénonitrobenzène a été choisit comme réaction modèle pour comparer les performances catalytiques de catalyseurs à base de ruthénium en fonction de la nature du support utilisé, MWCNTs ou CNFs-H. L'influence de certains paramètres tels que la température, la nature du substrat et un traitement thermique du catalyseur (activation) est présentée. Une explication des performances catalytiques est proposée après caractérisation du catalyseur par MET, TPD, TPR et PZC (Chapitre IV). Les nanostructures carbonnées produites et caractérisées ont été utilisées comme charge de renforcement d'hydroxyapatites connue comme biomatériaux. Nous avons étudié en particulier la capacité de germination du phosphate octocalcique par la méthode de croissance cristalline à composition constante (C4) (Chapitre V).In this work, we describe the different forms, the catalytic growth, the structure and properties of carbon nanotubes and nanofibres (Chapter I). Hydroxyapatite was used as catalyst support for the synthesis of multi-walled carbon nanotubes (MWCNTs) and nanofibres (CNFs) by catalytic chemical vapour deposition (C-CVD) in a fluidized bed reactor (Chapter II). After support removal by washing with diluted hydrochloric acid, a theoretical and experimental study of surface oxidation of carbon nanotubes by nitric acid treatment has been performed. It allows to identify and quantify the groups formed on the surface of carbon nanostructures and also to propose a mechanism for the formation of these groups (Chapter III). The functionalized nanotubes and nanofibers have been used as supports for heterogeneous catalysis. The hydrogenation of p-halonitrobenzene was used as model reaction to compare the catalytic performances of ruthenium supported on MWCNTs or CNFs-H catalysts. The influence of experimental parameters such as temperature, nature of the substrate and prior heat treatment (activation) of the catalyst on the catalytic activity and selectivity is presented. The catalytic performances have been correlated to the structure of the catalyst as determined from TEM, TPD, TPR and PZC analysis (Chapter IV). The carbon nanostructures produced have also been used as reinforcement fillers for hydroxyapatite-nanotube composites. We have studied in particular, the germination of octacalcium phosphate crystals under conditions of constant solution composition on the surface of the composite (Chapter V)

Trace Metal Elements in Different Categories of Drinking Water by Exploratory Analysis

The objective of this work was to assess the quality of different categories of water intended for human consumption through monitoring and quantification of metallic trace elements. Chosen study matrix was made up of tap water, bottled Moroccan water, bottled foreign water and finally surface water from Beni Mellal area: Ain Asserdoune and Bouyakoub. Four trace elements were studied namely: As, Cd, Cr and Pb. The assays were carried out using inductively coupled plasma technique equipped with Atomic Emission Spectrometer (ICP-AES). Dissimilarities between waters and correlations between metallic trace elements were carried out by Principal Component Analysis. According to the analytical results, Arsenic (As) would be much more present in foreign waters with an average value of 6.33µg/L followed by Moroccan surface water category with an average value of 6.191 µg/L. Cadmium (Cd) was also more present in Moroccan surface water category. Chromium (Cr) was much more present in Moroccan waters especially in natural water category with an average value of 45.65 µg/L followed by tap water with of 44.875 µg/L value. Lead (Pb) was much more present in Moroccan waters compared to foreign waters. Analysis results allow us to locate the different samples analyzed in relation to Moroccan drinking water standard and that of World Health Organization on the one hand and to classify different types of water according to their concentrations of metallic elements on the other hand

Synthèse par dépôt chimique en phase vapeur catalytique (C-CVD) de nanostructures de carbone et leurs applications en catalyse et pour des matériaux composites

Dans ce travail, nous décrivons les différentes formes, la structure, les propriétés et la croissance catalytique de nanotubes et nanofibres de carbone (Chapitre I). L'hydroxyapatite a été utilisée comme support de la phase active pour la synthèse de nanotubes de carbone multi-feuillet (MWCNTs) et de nanofibres de carbone (CNFs-H) par la technique de dépôt chimique en phase de vapeur catalytique (C-CVD) en lit fluidisé (Chapitre II). Après l'élimination du support par un simple lavage à l'acide chloridrique dilué, une étude théorique et expérimentale de l'oxydation de la surface de nanotubes de carbone par un traitement à l'acide nitrique a permis d'une part d'identifier et de quantifier les groupes formés à la surface de nanostructures carbonées et d'autre part de proposer un mécanisme pour la formation de ces groupes (Chapitre III). Les matériaux résultants après génération des fonctions carboxyliques de surface ont été utilisés comme support de catalyseur. L'hydrogénation du p-halogénonitrobenzène a été choisit comme réaction modèle pour comparer les performances catalytiques de catalyseurs à base de ruthénium en fonction de la nature du support utilisé, MWCNTs ou CNFs-H. L'influence de certains paramètres tels que la température, la nature du substrat et un traitement thermique du catalyseur (activation) est présentée. Une explication des performances catalytiques est proposée après caractérisation du catalyseur par MET, TPD, TPR et PZC (Chapitre IV). Les nanostructures carbonnées produites et caractérisées ont été utilisées comme charge de renforcement d'hydroxyapatites connue comme biomatériaux. Nous avons étudié en particulier la capacité de germination du phosphate octocalcique par la méthode de croissance cristalline à composition constante (C4) (Chapitre V).In this work, we describe the different forms, the catalytic growth, the structure and properties of carbon nanotubes and nanofibres (Chapter I). Hydroxyapatite was used as catalyst support for the synthesis of multi-walled carbon nanotubes (MWCNTs) and nanofibres (CNFs) by catalytic chemical vapour deposition (C-CVD) in a fluidized bed reactor (Chapter II). After support removal by washing with diluted hydrochloric acid, a theoretical and experimental study of surface oxidation of carbon nanotubes by nitric acid treatment has been performed. It allows to identify and quantify the groups formed on the surface of carbon nanostructures and also to propose a mechanism for the formation of these groups (Chapter III). The functionalized nanotubes and nanofibers have been used as supports for heterogeneous catalysis. The hydrogenation of p-halonitrobenzene was used as model reaction to compare the catalytic performances of ruthenium supported on MWCNTs or CNFs-H catalysts. The influence of experimental parameters such as temperature, nature of the substrate and prior heat treatment (activation) of the catalyst on the catalytic activity and selectivity is presented. The catalytic performances have been correlated to the structure of the catalyst as determined from TEM, TPD, TPR and PZC analysis (Chapter IV). The carbon nanostructures produced have also been used as reinforcement fillers for hydroxyapatite-nanotube composites. We have studied in particular, the germination of octacalcium phosphate crystals under conditions of constant solution composition on the surface of the composite (Chapter V).TOULOUSE-INP (315552154) / SudocSudocFranceF

Visualization of medical concepts represented using word embeddings: a scoping review.

International audienceBackgroundAnalyzing the unstructured textual data contained in electronic health records (EHRs) has always been a challenging task. Word embedding methods have become an essential foundation for neural network-based approaches in natural language processing (NLP), to learn dense and low-dimensional word representations from large unlabeled corpora that capture the implicit semantics of words. Models like Word2Vec, GloVe or FastText have been broadly applied and reviewed in the bioinformatics and healthcare fields, most often to embed clinical notes or activity and diagnostic codes. Visualization of the learned embeddings has been used in a subset of these works, whether for exploratory or evaluation purposes. However, visualization practices tend to be heterogeneous, and lack overall guidelines.ObjectiveThis scoping review aims to describe the methods and strategies used to visualize medical concepts represented using word embedding methods. We aim to understand the objectives of the visualizations and their limits.MethodsThis scoping review summarizes different methods used to visualize word embeddings in healthcare. We followed the methodology proposed by Arksey and O’Malley (Int J Soc Res Methodol 8:19–32, 2005) and by Levac et al. (Implement Sci 5:69, 2010) to better analyze the data and provide a synthesis of the literature on the matter.ResultsWe first obtained 471 unique articles from a search conducted in PubMed, MedRxiv and arXiv databases. 30 of these were effectively reviewed, based on our inclusion and exclusion criteria. 23 articles were excluded in the full review stage, resulting in the analysis of 7 papers that fully correspond to our inclusion criteria. Included papers pursued a variety of objectives and used distinct methods to evaluate their embeddings and to visualize them. Visualization also served heterogeneous purposes, being alternatively used as a way to explore the embeddings, to evaluate them or to merely illustrate properties otherwise formally assessed.ConclusionsVisualization helps to explore embedding results (further dimensionality reduction, synthetic representation). However, it does not exhaust the information conveyed by the embeddings nor constitute a self-sustaining evaluation method of their pertinence

Master’s Degree in Health Data Science: Implementation and Assessment After Five Years

International audienceHealth data science is an emerging discipline that bridges computer science, statistics and health domain knowledge. This consists of taking advantage of the large volume of data, often complex, to extract information to improve decision-making. We have created a Master’s degree in Health Data Science to meet the growing need for data scientists in companies and institutions. The training offers, over two years, courses covering computer science, mathematics and statistics, health and biology. With more than 60 professors and lecturers, a total of 835 hours of classes (not including the mandatory 5 months of internship per year), this curriculum has enrolled a total of 53 students today. The feedback from the students and alumni allowed us identifying new needs in terms of training, which may help us to adapt the program for the coming academic years. In particular, we will offer an additional module covering data management, from the edition of the clinical report form to the implementation of a data warehouse with an ETL process. Git and application lifecycle management will be included in programming courses or multidisciplinary projects

Master’s Degree in Health Data Science: Implementation and Assessment After Five Years

International audienceHealth data science is an emerging discipline that bridges computer science, statistics and health domain knowledge. This consists of taking advantage of the large volume of data, often complex, to extract information to improve decision-making. We have created a Master’s degree in Health Data Science to meet the growing need for data scientists in companies and institutions. The training offers, over two years, courses covering computer science, mathematics and statistics, health and biology. With more than 60 professors and lecturers, a total of 835 hours of classes (not including the mandatory 5 months of internship per year), this curriculum has enrolled a total of 53 students today. The feedback from the students and alumni allowed us identifying new needs in terms of training, which may help us to adapt the program for the coming academic years. In particular, we will offer an additional module covering data management, from the edition of the clinical report form to the implementation of a data warehouse with an ETL process. Git and application lifecycle management will be included in programming courses or multidisciplinary projects

Novel microwave synthesis of ruthenium nanoparticles supported on carbon nanotubes active in the selective hydrogenation of p-chloronitrobenzene to p-chloroaniline

Carbon nanotubes (CNTs) have been employed for the preparation of supported ruthenium nanoparticles using, for the first time, a low boiling alcohol or a mixture ethanol/water as solvent/reducing agent under microwave irradiation as heating source. These systems were employed as catalysts in the selective hydrogenation of p-chloronitrobenzene (p-CNB) to p-chloroaniline (p-CAN) and resulted efficient systems for the selective reduction of the nitro group in p-CNB under mild reaction conditions (60 degrees C and 4 MPa of H-2), while the C-Cl bond remains intact, thus allowing the almost complete substrate conversion with total selectivity to the target product. These supported ruthenium nanoparticles are characterized by small average diameters and narrow particle size distributions, even if synthesized in the absence of any additional stabilizing agents and appear very promising systems also for other catalytic applications. (C) 2012 Elsevier B.V. All rights reserved

Analysis of the molecular electrostatic potential of the chemical reactivity of p-nitrophenol, p-aminophenol and p-methylphenol by the quantum method

There are many methods in quantum chemistry such as semi-empirical methods, ab initio methods, and density functional methods. All of these methods can determine the atomic molecular properties. In this work, we chose the density functional method (DFT) to determine electrostatic potential, frontier molecular orbitals (FMO), and optimization of molecules such as p-nitrophenol, p-methylphenol, and p-aminophenol. The determination of interatomic distances, nonlinear optical descriptors (NLO) such as dipole moment (μ), polarizability (α), first hyperpolarizability (β) and second hyperpolarizability (γ). The analysis of the potential energy surface was carried out by the density functional theory (DFT) method using the Becke, Lee, Yang, and Parr Gradient Corrected Functional (B3LYP) exchange and correlation with the standard base 6-311G (d, p). This method is implemented in the program Gaussian 09. The results of the energy gap, chemical hardness, dipole moment, and hyperpolarizability show that p-nitrophenol is the reactive molecule, and p-aminophenol is the stable molecule. The electrophilic attack occurs at the O7, O10, and O9 sites for p-nitrophenol, O7 for p-methylphenol, and O7, N13 for p-aminophenol