Dissertations / Theses on the topic 'Matrices oxydées'
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Vallerini, Barbosa Itália. "Nanocristaux oxydes luminescents pour le développement de nanosondes de température in vivo." Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALI125.
Biological thermal modifications are common events during abnormal cellular metabolic activities. Indeed, thermal aberrations – such as an increase in local tissue temperature – are directly related to the detection of inflamed areas, the presence of tumors, or other diseases. In addition to contributing to the diagnosis of diseases, the determination of local temperature in biological systems can also help with their treatment. For instance, in hyperthermia, the increase in temperature must be induced in tumor tissues up to cytotoxic levels in order to kill cancer cells and therefore, it assists in the cancer treatment. However, the increase in temperature must be carried out in a controlled and well-localized manner to target cancer cells, while avoiding overheating of surrounding healthy tissue. Furthermore, to determine such biological aberrations, temperature variations must be accurately determined. The thermometric performance of the nanothermometers was determined by calculating the relative thermal sensitivity (S_r) using the ratiometric luminescence intensity approach. Furthermore, our study made it possible to raise some hypotheses that can effectively contribute to the thermometric performance of thermal probes. We use the technique of the intensity ratio of two luminescence peaks for which the values of S_r can be optimized by co-doping the nanocrystals with two, or more, Ln3+ ions and by using oxide matrices presenting different phonon energies. Thus, due to its generic nature and synthesis flexibility, the Pechini method was chosen to synthesize several oxide matrices, Y2O3, Y2Ge2O7, Y3Al5O12 (YAG), Y3BO6 and YBO3. The nanocrystals were firstly monodoped with Nd3+ and posteriorly, codoped with Nd3+ -Yb3+ to improve the thermal probe properties within the biological windows of near infrared. In addition, we optimized the doping concentrations in the host matrices for greater efficiency in luminescence detection in biological organisms. We experimentally observed that Sr values are strongly impacted to the phonon energy of the matrix. We analyzed that by Nd3+ -Yb3+ codoping the thermometric performance of nanocrystals is improved compared to nanocrystals mono doped with Nd3+. Our study of different oxides shows that the YAG and Y2O3 matrices are the most promising matrices for the luminescence nanothermometry in vivo application. Lastly, YAG individual nanocrystals (non-agglomerated as in the case of Pechini syntheses) of size 60 nm and controlled morphology were obtained in solution by the solvothermal method to advance in further studies in biological applications. We observed that the YAG nanothermometers suitable for the purpose have a S_r equal to 0.47 %·K-1 and a thermal resolution of 0.3 K. In vivo experimental tests are required to validate the findings of this study; however, our results obtained on the performance of YAG: Nd3+ -Yb3+ nanocrystals has been showing high potential for in vivo applications of ratiometric luminescence nanothermometry
Boutenel, Florian. "Comportement d’une matrice alumine-silice au cours de l’élaboration de composites à matrice céramique oxyde/oxyde." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2020. http://www.theses.fr/2020EMAC0011.
Oxide/oxide ceramic matrix composites can be used for structural applications operating continuously at temperatures between 500°C and 900°C under oxidizing environments, such as in areas close to aircraft engines. In particular, composites based on a matrix combining alumina and silica are promising. In addition, the processing of these materials comprises several steps. Two of them are essential: the impregnation of the fibrous reinforcement with the suspension and the sintering of the matrix. This PhD thesis focuses on the processing of oxide/oxide ceramic matrix composites using an alumina-silica matrix. It is derived from an aqueous suspension in which the two species are initially present as particles. The aim of this work is to study the behaviour of such a system during the various stages of the manufacturing, i.e. to establish the relationships between processing/microstructure/properties, in order to propose an optimal composition of the matrix regarding the process and the required properties. In particular, the silica proportion will be a crucial parameter. Firstly, since the quality of the impregnation step is based on the ability of the suspension to flow within the fibrous structure, a rheological characterization of the oxide suspensions has been carried out. The rheological behavior has been interpreted on the basis of the domains of predominance of the different interactions within the suspension. Also, the influence of the various suspension characteristics, such as the solid fraction and the alumina-silica ratio, has been examined. Then, the behaviour of this system during the sintering has been studied since this thermal treatment should lead to a microporosity that respects the concept of weak matrix composites. The sintering mechanisms have been identified while the influence of the various parameters on the kinetics has been qualified. Also, relationships with the mechanical properties of the matrix have been established. Finally, composites with Nextel™ 610 reinforcements and a porous alumina-silica matrix have been fabricated and characterized
LE, GENDRE LAURENT. "Une nouvelle classe de composes oxyazotes : entites n-n dans des matrices oxydes." Rennes 1, 1997. http://www.theses.fr/1997REN10210.
Andron, Inès. "Oxydes et fluorures photochromiques inorganiques : approches expérimentale et calculatoire." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0104.
In the quest for ideal and advanced photochromic inorganic compounds, this PhD work is focused on the study of oxidation number switch as a result of photo-redox processes generated by UV-light irradiation in both inorganic fluoride and oxide matrices. The photo-redox reactions involve transition metal (Mo5+/Mo6+) or rare-earth (Ce3+/Ce4+) doping cations used as chromophores or luminescent species inducing the photochromic properties in these materials, respectively.First, deep structural and optical characterizations have allowed the full understanding of the photo-chromo-luminescent properties taking place in several elpasolite compositions (deriving from a double-perovskite structural-type). These materials exhibit a bistable photochromism. Actually, these Ce-doped matrices are characterized by an initial blue broad band emission, ascribed to the Ce3+ luminescent ion. A new luminescent species (In+) is created by redox reaction between Ce3+ and In3+ after long-time UV irradiation. A yellow to red range emission attributed to the occurrence of In+ species is then observed. The photochromism is reversible with a long-time exposure under shorter UV wavelength. The features of both indium or cerium emission bands depend on the composition of the matrix due to a change in the chemical bonds iono-covalent character in link with the crystal field. A quantum chemical modelling based on DFT calculations involving Cerium-doped systems has been performed to identify the prevalent defect chemistry and corresponding global/local geometry incidences of cation substitution. Substitution energies were systematically investigated allowing to propose some specific models of Cerium incorporation as being the most likely to occur. In an attempt to define less costly (In-free) compounds, a study of the photochromic properties of Pr or Ce-doped CaSnF6 matrix (double ReO3 structure) has been achieved. A less intense photochromic phenomenon was observed due to photo-oxidation of the rare-earth ion, the reverse process requiring to maintain the compound during long-times under dark conditions.Secondly, a study of the reversible photo-induced colour change of intimate mixtures of ZnO and MoO3 powders has been performed. Under UV irradiation (with an energy over the ZnO gap) a colouring process is observed due to the intervalence charge transfers (Mo5+→Mo6+) inside the MoO3 compound. It was clearly demonstrated that the creation of reduced Mo5+ ions occurred thanks to the electrons provided by the zinc oxide conduction band which are created in link with the UV excitation, through the material interfaces acting as a Schottky barrier. The bleaching process occurs without any stimulus into dark conditions. From soft chemistry routes, the morphology, the chemical composition (Al-doping, cation/oxygen ratio modulation) of the ZnO and MoO3 compounds, along with the mixture composition (ZnO/MoO3 ratio) were optimized to enhance the photochromic contrast
Seve, Sophie. "Caractérisation cellulaire et tissulaire de la lysyl oxydase et de la lysyl oxydase-like." Lyon 1, 2002. http://www.theses.fr/2002LYO10078.
Bechara, Rafeh. "L'ion Cu+ dans différentes matrices : aspects physico-chimiques et catalytiques." Lille 1, 1986. http://www.theses.fr/1986LIL10037.
Bellafrouh, Khalid. "Etude théorique des multiplets de spin de quelques ions "3d" dans des matrices oxydes et fluorures." Phd thesis, Université Claude Bernard - Lyon I, 1990. http://tel.archives-ouvertes.fr/tel-00747434.
Thomassin, Laetitia. "Étude comportementale de la Lysyl oxydase (LOX) et de la Lysyl Oxydase-like (LOXL) au cours de l'élastogenèse : implication de leurs pro-régions." Lyon 1, 2005. http://www.theses.fr/2005LYO10164.
Ben, Ramdane Camélia. "Etude et modélisation du comportement mécanique de CMC oxyde/oxyde." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0077/document.
Oxide/oxide CMCs are good candidates for thermostructural applications. Themechanical behaviour and damage mechanisms of two alumina/alumina composites with two andthree dimensional woven reinforcements were studied and compared. The microstructure of theseweak matrix CMCs was characterized by porosimetry and NDT methods, such as IR thermography,ultrasound scanning and X-ray tomography, which highlighted initial defects. The mechanicalbehaviour was studied through tensile tests, as well as compression tests in the case of the twodimensionalreinforced CMC. These tests were conducted at room temperature, in the fibres directionsand in the ±45° direction. In order to fully exploit these tests, several extensometry and damagemonitoring methods, such as IR thermography and acoustic emission, were used. Young’s moduli andmaximum stresses and strains of the two-dimensional reinforced CMC developed at Onera appearedto be higher than those available in the literature. The damage mechanisms of the materials weredetermined by post mortem SEM observations and in situ testing in a SEM, which made it possible toassess the nocivity of initial defects. Studying the mechanical behaviour of these composites finallyenabled the development of a three-dimensional damage model that will facilitate the furtherdevelopment of such materials, through finite element analysis. Finally, some improvements regardingthe manufacturing processes and the instrumentation for damage monitoring were suggested forfuture studies
Leite, Rubim Rafael. "Graphene oxide sheets confined within anisotropic fluid matrices." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0209/document.
Since the discovery of graphene oxide (GO), the most accessible of the precursors of graphene, this material has been widely studied for applications in science and technology. The motivation of this work is to study with a fundamental perspective the coupling between amphiphilic bilayers, which can be seen as an anisotropic matrix formed of two-dimensional objects, and another two-dimensional object, namely the graphene oxide sheet when they are dispersed in a common solvent. The competition between the intrinsic elasticities of the bilayers and GO sheets, as well as between direct bilayer-bilayer, bilayer-GO and GO-GO interactions allows us to envisage a rich polymorphism, depending on the composition of the system. Following the development of a dedicated procedure for controlling in an extended range of GO content the binary GO-water system, the confined domain of aqueous GO dispersions was first investigated, and the ternary phase diagram then constructed. The obtained systems have been characterised, using techniques such as optical microscopy, light and x-ray scattering. Elastic and thermodynamic properties have been described by applying, and adapting to the scope of this study, models for two-component lamellar stacks
Desde sua descoberta, o grafeno oxidado (GO), o mais acessível dos precursores do grafeno,tem sido amplamente utilizado para aplicações na ciéncia e tecnologia. A motivação destetrabalho é de estudar, de um ponto de vista fundamental, o acoplamento entre bicamadas anfifílicas auto-organizadas (que podem ser vistas como uma matriz anisotrópica formada por objetos bidimensionais) e um objeto ele mesmo bidimensional, neste caso a folha de óxido de grafeno, quando estão dispersados em um solvente comum.A competição entre as elasticidades intrínsecas das bicamas e das folhas de GO, assimcomo as interaçãoes diretas bicamada-bicamada, bicamada-GO e GO-GO, permitem esperar um rico polimorfismo em função da composição do sistema. Seguindo o desenvolvimento de um procedimento destinado ao controle, em um intervalo extendido da quantidade de GO, o sistema binário GO-água, o domínio confinado de dispersões aquosas de GO foi explorado e, em seguida, o diagrama de fases ternário contruído.Os sistemas obtidos foram caracterizados por t_ecnicas como microscopia ótica, espalhamento dinâmico de luz e espalhamento de raios-x à baixos ângulos. As propriedadeselásticas e termodinâmicas foram descritas pela aplicação de modelos inicialmente concebidos para fases lamelares à dois constituintes e adaptados ao escopo deste estudo
Vallet, Sylvain D. "Structure et interactions de la lysyl oxydase et de fragments de la matrice extracellulaire." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1296.
The extracellular matrix is an intricate tridimensional network supporting cells and a bioactive molecule reservoir involved in the regulation of cell behavior. It is composed of 1027 proteins in humans (Naba et al., Matrix Biol. 2016), including 274 of the core matrisome and 753 associated proteins (growth factors and extracellular matrix regulators) and 6 glycosaminoglycans including 5 sulfated. The extracellular matrix is altered in numerous pathologies (Bonnans et al., Nat. Rev. Mol. Cell Biol. 2014). The lysyl oxidase is responsible for the cross-linking of collagens and elastin and is involved in many cancers. The extracellular matrix is a reservoir of bioactive fragments named matricryptins which are released by proteolysis of extracellular matrix proteins and regulate numerous biological processes like angiogenesis and adipogenesis (Ricard-Blum et Vallet, Matrix Biol. 2017). We have expressed under a recombinant form in human cells some matricryptins including the ectodomains of the membrane collagens XIII, XVII, XXIII and XXV and have identified their extracellular partners. We have characterized the propeptide of lysyl oxidase by SEC-MALS, dynamic light scattering, and SAXS and have built a coarse-grained 3D model by SAXS-derived constraints. We have identified 17 new partners of this fragment and analyzed the mutant Arg158Gln which has no biological activity. This mutation has been identified in humans and inhibits the propeptide anti-proliferative properties. It is associated to an increased risk of breast cancer (Min et al., Cancer Res. 2009). We have expressed the mature lysyl oxidase and modelled its tridimensional structure using available data. All the interactions identified in this study were associated to manually curated interactions described in the literature to build the first version of the human extracellular interactions network
Guel, Nicolas. "Comportement mécanique de composites oxydes : Relations procédé-microstructure-propriétés." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI104/document.
The aim of this thesis is the fine understanding on the influence of the microstructure on oxide-based ceramic matrix composites mechanical properties. These materials are good candidate for new generation of civil aircraft engines. The aim of this work is to establish a relationship between the microstructural defects generated by the manufacturing process and the mechanical behavior of the composite. These heterogeneities seem to influence the appearance and the propagation of damage mechanisms. This study is realized on three kinds of bi-dimensional oxide composites generated from three different manufacturing processes. These processes create three kinds of microstructure. Porosimetric and μ-tomographic analyses allow estimating the distribution of microstructural defects and establish typical microstructure of each oxide composite. Based on these preliminary analyses, mechanical behavior of each kind of oxide composites is studied through several representative scales. On the one hand, mechanical tensile tests are carried out in order to estimate the mechanical properties of the studied materials in the weaving plane. On the other hand, the implementation of in-situ mechanical tests allows the visualization of damage mechanisms appearance and propagation. These observations improve the understanding of the role of microstructural defects on the activation of damage mechanisms. Damage kinetics of each mechanical test are inspected through AE (Acoustic emission) analysis. This monitoring helps to link mechanical behavior with microstructural damage. In parallel with global AE analysis, AE clustering is achieved. These classifications are based on two kinds of AE sensor with different properties. Data fusion from the two sensors is accomplished. This technique allows more robust AE clustering. Cluster labelling is proposed thanks to damage mechanisms observed during in-situ mechanical tests. Damage scenarios are set up owing to macroscopic mechanical test, in-situ analysis and AE labelling. Thus, it is possible to establish the influence of each kind of microstructural defect on oxide-based CMCs mechanical behavior
Salvat, Stéphanie. "Propriétés électriques non linéaires de matériaux composites à matrices polymères chargées avec de l'Oxyde de Zinc." Bordeaux 1, 2002. http://www.theses.fr/2002BOR12587.
Cueff, Sébastien. "Transfert d'énergie entre nanoclusters de Silicum et Erbium dans des matrices oxydes et nitrures de Si: applications à des diodes électroluminescentes." Phd thesis, Université de Caen, 2011. http://tel.archives-ouvertes.fr/tel-00934714.
Cueff, Sébastien. "Transfert d’énergie entre nanoclusters de Silicum et Erbium dans des matrices oxydes et nitrures de Si : applications à des diodes électroluminescentes." Caen, 2011. http://www.theses.fr/2011CAEN2039.
This work is based on the analysis and optimization of an alternative material to replace metallic interconnections of integrated circuits. This material is an SiO2 matrix containing Silicon-nanoclusters (Si-nc) and Erbium ions (Er3+). Thanks to an energy transfer between Si-nc and Er3+, the strong absorption of Si-nc in the visible range results in the indirect excitation of Er3+ ions that thus emit at 1. 5 µm. The goal is to optimize the emission properties of Er3+ at 1. 5 µm, and for that, to maximize the energy transfer between Si-nc and Er3+. First, the work is directed on thermal treatments during and after the deposition. Then, we analyze the influence of the film thickness on the material’s optical properties and we show that thinnest films (< 150 nm) contain a low number of that reduces the number of excited erbium. We demonstrate that this problem can be overcome by increasing the silicon concentration, hence raising the number of sensitizers for Er3+. It is also shown that Er3+ ions benefit from a multilevel excitation by Si-nc sensitizers. A second part of the work consists in the realization of light-emitting diodes (LEDs) and to optimize their emission at 1. 5 µm. We show that thickness and silicon excess must be chosen concomitantly to optimize optical and electrical properties of LEDs. In a last part we show that LEDs’ properties can be enhanced using nitrogen-based matrices like oxynitrides or nitrides as hosts for Er3+
Carles, Valérie. "Elaboration et caractérisation physico-chimique et électromagnétique de nanoparticules ferromagnétiques dispersées dans une matrice du type oxyde." Toulouse 3, 1995. http://www.theses.fr/1995TOU30227.
PERALDI, DECITRE MARIE. "Les isoformes de la lysyl oxydase : de la matrice extracellulaire au noyau (doctorat : bases fondamentales de l'oncogenese)." Paris 11, 1998. http://www.theses.fr/1998PA11T008.
Billard, Romain. "Mise au point d’un composite à fibre oxyde et matrice d’aluminosilicate de baryum modifiée." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0291/document.
The main purpose of the present work is to propose a new BaAl2Si2O8 (BAS) composite reinforced with alumina fibers exhibiting similar physical properties but a higher refractoriness than SiO2 / SiO2 composites. The hexagonal crystal form of BAS is the stable one at high temperatures. However, it is metastable below 1590 °C and it is therefore necessary to stabilize it in order to prevent crystalline transformations. The stabilization of the hexagonal form by atomic substitution, including rubidium at 5 atomic % has been chosen. Regarding the matrix BAS composite, the alumina fibers selection has been justified by their low physical and chemical reactivity with this material. Several elaboration methods of the BAS matrix and of the BAS / alumina composite have been investigated. The development by "reactive spark plasma sintering" (R-SPS) brings an important benefit in terms of reduced elaboration time and yield. This saving time thus limits the BAS exposure to high temperatures and the risk of transformation into monoclinic. Nevertheless, the SPS shaping of oxide materials, including the BAS, is confronted with the presence of important thermal gradient within the sample. This is why shaping in a heating mold is currently in progress, as an alternative to the SPS. This system should allow the use the same thermal cycles as for SPS, but with lower thermal gradient
Klangsin, Junya. "Incorporations de nanoparticules de silicium dans des matrices obtenues par voie Sol-Gel : élaboration et caractérisations." Lyon 1, 2008. http://n2t.net/ark:/47881/m6p55kmn.
The optoelectronic properties of silicon nanoparticles are very different from those of bulk silicon. Their low sizes (a few nanometers) provide the quantum properties and they present a strong luminescence in the visible at ambient temperature. Therefore, they are very interesting for different applications (for example: light-emitting diode (LED) based on silicon only, non volatile memory, sensor, drugs transport, etc…). In general, these nanoparticles have to be integrated in the matrix in order to be able to exploit their properties. In this work, we have proposed to incorporate the silicon nanoparticles, obtained by electrochemical etching of a silicon substrate and then milling, in oxide matrices by using the Sol-Gel method. The principal advantages of these techniques are: low cost, simplicity, and various choices of matrix offered. Three matrices chosen herein (SiO2, ZrO2 and TiO2) allow us to sweep a wide range of band gap and dielectric constant. For each matrix, different concentrations of nanoparticles and annealing conditions were carried out. The obtained results are quite satisfactory. Structural studies confirm the presence of nanoparticles in every matrix. The compressive stress induced by their matrix is also observed. Photoluminescence studies show that the nanoparticles conserve their optical properties when they are incorporated in the SiO2 matrix and the ZrO2 matrix but not in the TiO2 matrix. The stability of the nanoparticles towards the influence of annealing temperature is more important for the SiO2 matrix. Besides, in photoluminescence study, the coupling effect among nanoparticles increasing with their concentration is observed
De, Campos Matthieu. "Valorisation de matière faiblement radioactive comme réactif dans la synthèse de matrices cimentaires." Thesis, Lille 1, 2020. http://www.theses.fr/2020LIL1R016.
In the context of pressurized water nuclear reactors (PWRs), fuel fabrication generates low-level radioactive materials in the form of low-reactivity and relatively dense metal oxides. These materials, in the form of aggregates, are currently stored pending their reuse in nuclear fuel or in alternative solutions. This thesis studies their valorization as additives in the synthesis of cement matrices (pastes and mortars), for the development of shielding materials against ionizing radiation, such as γ rays. The state of the art (Chapter I) focuses on the generation of this weakly radioactive material in the French nuclear fuel cycle, on the photon-matter interactions, on cementitious matrices, and on the use of radioactive materials in cementitious matrices. The experimental work has required to develop miniaturized physico-chemical characterization methods adapted to radioactive materials (Chapter II), in order to compare them with formulations using non radioactive analogs. For the development of cement-based materials, a magnesium potassium phosphate cement (MKPC) and a pure Portland cement are used. Workability, setting time, mechanical compressive strength, dimensional stability, homogeneity of the microstructure and temperature resistance are optimized. For MKPC pastes, the mechanical strength depends on the MgO/KH2PO4 molar ratio (Chapter III). In order to optimize the integration of the dense metal oxides, MKPC are formulated at stoichiometry, although this composition, without additives, is characterized by significant swelling. The addition of powdered mineral additives (fly ash, dense metal oxides) enabled to inhibit swelling and avoid phase segregation. With Portland cement, the incorporation of metal oxides is performed on mortars, with a granular skeleton (Chapter IV), and it is carried out in two ways: either as a supplement to an optimized formulation, or by volume replacement of the fine parts of the granular skeleton. In both cases, compressive strengths are obtained with values above 50 MPa at 28 days, and a good resistance to temperatures up to nearly 250°C. A third incorporation method is possible, which requires the synthesis of cement/metal oxide granules. The fifth and last chapter compares the mechanical and shielding performances of cement matrices incorporating the dense metal oxides. It also quantifies the interactions of these metal oxides with the environment (by reactivity experiments in contact with cementitious waters at ambient temperature and pressure or beyond, and leaching tests). Depending on the performance of the two types of cement matrices developed, different uses are possible, e.g. waste encapsulation or structural and temperature resistant materials
Borel, Agnès. "Les lysyl oxydases LOX, LOXL et LOXL2 : caractérisation et rôle dans la réticulation des protéines matricielles." Lyon 1, 2003. http://www.theses.fr/2003LYO10020.
Honoré, Stéphane. "Rôle des intégrines per se dans l'organisation du cytosquelette actinique et la progression du cycle cellulaire dans une lignée d'adénocarcinome colique (Caco-2)." Aix-Marseille 2, 2001. http://theses.univ-amu.fr.lama.univ-amu.fr/PHA_2001_1546.pdf.
Pichol-Thievend, Cathy. "Rôle de la Lysyl oxidase-like-2 dans l'assemblage de la matrice extracellulaire et l'angiogenèse." Paris 6, 2012. http://www.theses.fr/2012PA066446.
Sprouting angiogenesis is associated with extensive extracellular matrix (ECM) remodeling. The molecular mechanisms involved in building the vascular microenvironment and its impact on capillary formation remain elusive. We identified lysyl oxidase like protein 2 (LOXL2) which accumulates in the endothelial hypoxic ECM. We showed that LOXL2 is expressed in capillaries during developmental and pathological angiogenesis. Knocking-down LOXL2 proper organization of endothelial cells and formation of capillaries, resulting in non functional intersegmental vessels (ISV) in zebrafish embryos. Surprisingly, pharmacological inhibition of lysyl oxidase activity did not affect ISV formation. Further investigation in a 3D culture model confirmed that LOXL2 expression was required for capillary formation. Pharmacological inhibition of LOXL2 enzymatic activity only slightly affected lumen formation, suggesting that mechanisms independent of LOXL2 enzymatic activity were responsible for defective capillary morphogenesis. We hypothesized that LOXL2 could regulates organization of the vascular basement membrane. Whereas knocking-down LOXL2 expression led to inhibition of collagen IV assembly, inhibition of LOXL2 enzymatic activity only affected collagen IV crosslinking. In conclusion, we show that LOXL2 regulates neovessel formation through assembly of the vascular basal lamina and collagen IV organization and provide further novel evidence that LOXL2 regulates sprouting angiogenesis independently of its lysyl oxidase activity
Rodríguez, Martínez Yerila. "Plasmonic Cu nanoparticles inclusion in ZnO and Cu2O matrices for enhanced photoconversion of all-oxide optoelectronics." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0208.
In this work we present the results on in-situ growth of plasmonic copper (Cu) nanoparticles (NPs) into a p-Cu2O matrix by using reactive magnetron sputtering of a Cu target and adjusting the oxygen flowrate. It was possible to observe, for oxygen-poor conditions, the formation of CuNPs-Cu2O composites presenting the signature of the localized surface plasmon resonance (LSPR) phenomenon. Devices based on the studied nanocomposites interfaced with zinc oxide (ZnO) were characterized by J-V and spectral photocurrent measurements, showing a photocurrent density increase under optical illumination as a result of the plasmonic particles incorporation and consequent hot carriers injection. In the second part of the manuscript, the results about the rapid thermal annealing (RTA) of the CuNPs-Cu2O composites under oxygen-poor conditions and their properties evolution when temperature increases are presented. At temperature higher than 150 ºC it was possible to see a copper segregation towards the surface, increase in the crystal preferential orientation of Cu2O and improvement of the LSPR signal. Electrical response of devices constituted by the composite layers interfaced with ZnO and annealed at 200 ºC showed a further increase in the photocurrent resulting from the LSPR of Cu NPs at the devices surface. Finally, the synthesis of Cu nanoparticles through a gas aggregation source (GAS) and the subsequent fabrication of ZnO-CuNPs multilayer structure with plasmonic response were studied. The resulted composite revealed LSPR response and the presence of Cu particles acting as nucleation points for highly oriented ZnO conical grains
Verdenelli, Martine. "Elaboration par procédé sol-gel de couches minces oxydes à gradient de porosité : évaluation en tant qu'interphases dans les composites à matrice céramique SiC-SiC." Lyon 1, 2002. http://www.theses.fr/2002LYO10203.
Hoffmann, Céline. "Bioconjugaison de la fibronectine à des sondes exogènes : du fluorophore organique à la nanoparticule hybride." Cergy-Pontoise, 2010. http://biblioweb.u-cergy.fr/theses/2010CERG0481.pdf.
Fibronectin (Fn) is a structural protein of extracellular matrix (ECM) and is implicated into many cellular behavior (adhesion, migration…). Follow the becoming of an ECM protein as Fn is possible only via imaging dyes. The aim of this PhD work is to conjugate Fn to different exogenic dyes : organic fluorophore (and two sorts of double detection hybrid nanoparticles. The study focuses on bioconjugation impact onto Fn structure and biological functionalities. This work put in evidence the importance of controlling bioconjugation conditions particularly bioconjugation stœchiometry, pH value and solvent condition. Getting functional Fn-FITC complex make possible the following of Fn matrix remodeling simultaneously of cellular migration. The Fn/nanoparticles conjugate presents a correct global conformation and specific interaction with cells
Tingaud, David. "Contribution au contrôle du frittage SHS de composites à matrice intermétallique et de céramiques de type oxyde." Limoges, 2006. http://www.theses.fr/2006LIMOA001.
De, Rancourt Yoann. "Dispersion de charges d'oxydes de terres rares, Er2O3 et Pr6O11, dans une matrice polymère." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20202.
This thesis focuses on the incorporation of mineral fillers of erbium oxide, Er2O3, and praseodymium oxide, Pr6O11, in an elastomeric polymer matrix, in the context of an industrial project to replace the lead in radiation protection equipment. The actual purpose of this thesis was to improve the dispersion of the fillers in the matrix through chemical treatment processes of these particles. Various types of surface functionalization were used to compatibilize them with an organic matrix, in particular by grafting compounds such as phosphonic acids. Hence, several phosphonic acids have been successfully used for the functionalization of both types of fillers. The characterization of these functionalizations is an important part of this project. Innovative analysis techniques, both direct and indirect have been used for this purpose, namely Py-GC/MS to detect the chemical compounds anchored to the surface of the fillers, X-ray fluorescence and FTIR spectroscopy with a quantification target, but also a study of sedimentation kinetics of the fillers in an organic medium. Finally, composites were obtained by mixing the fillers, untreated and treated, with a polyurethane matrix. Tensile tests have clearly shown an improvement of mechanical properties for some of the composites, due to the functionalization of the fillers by phosphonic acids
Benazzouk, Louiza. "Approche du comportement dynamique d'un oxyde liquide dans un matériau composite autocicatrisant " MAC "." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00984446.
Lahalle, Marie-Pierre. "Étude des propriétés spectroscopiques du neptunium IV dans les matrices monocristallines ThSiO₄ et ThO₂." Paris 11, 1986. http://www.theses.fr/1986PA112206.
This thesis is concerned, in a first time, with the spectroscopy of the Np4+ ion diluted in the single crystal of ThSi04. Crystals of ThSi04 with a tetragonal structure, doped with neptunium 237 were grown by the flux method (the rate of Np included in these crystals being about 0. 16 %). The crystallographic structure of the obtained crystals has been confirmed at room temperature by X-rays diffraction. Raman diffusion experiments performed between 300 K and 4,2 K have shown that no phase transition occurs at low temperature. Then, the site symmetry of Np4+ in ThSi04 remains D2d at 4. 2 K (temperature of the recorded optical spectra). On the optical polarized absorption spectra of ThSi04:Np4+, most of the excitated Stark levels coming from the first J states 4r11/2' 4p3/2 and 4r1V2 have been assigned. Moreover, fluorescence experiments have permitted to identify two of the Stark components of the lower multiplet 4r9/2 On the whole, 29 energy levels have been used for the spectroscopie parameter calculations: pk, s and Bkq which defined the crystal field interaction. In order to enlarge the spectroscopy knowledge of Np4+, the optical analysis of Np4+ in Th02 have been performed in a second time. The cubic structure of the thorium dioxide provides an Oh symmetry for the Np4+ ions. Owing to the existence of an inversion center in such a symmetry, the pure dipolar electric transitions are theoretically forbidden and only the vibronic transitions are allowed. This results in a more difficult analysis than for ThSi04. The combined analysis of the spectra recorder at 4. 2 K and higher temperatures allows us to deduce the pure electronic transitions. A first interpretation has permitted to identify about fifteen excitated Stark levels of Np4+. The comparison of the spectroscopie parameters obtained in ThSi04:Np4+ and Th02:Np4+ allows us to deduce threlative covalent effect between Np4+ and these two crystalline environments
Delerue, Johann. "Matrices de bolomètres supraconducteurs à haute température critique pour l'infrarouge : matériaux, technologies et caractérisations optiques." Paris 6, 2002. http://www.theses.fr/2002PA066098.
Danset, Delphine. "Etude des premières étapes réactionnelles de l'oxydation du cobalt mono- et diatomique par l'oxygène moléculaire par isolation en matrice de gaz rare et spectroscopies d'absorption électronique et vibrationnelle." Paris 6, 2004. http://www.theses.fr/2004PA066075.
Lelarge, Virginie. "Rôle de la lysyl oxidase-like-2 endothéliale et tumorale au cours de l’angiogenèse dans le carcinome du rein à cellules claires." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066421/document.
Angiogenesis is a major process in microenvironment remodeling which is mainly induced by hypoxia and VEGF. Lysyl oxidase like-2 (LOXL2) belongs to lysyl oxidase family involved in extracellular matrix crosslinking. Our team previously described that LOXL2 is a hypoxia-target, which is secreted by endothelial cells and accumulated into endothelial extracellular matrix. We also demonstrated that LOXL2 stimulates developmental angiogenesis. Moreover, several studies showed that LOXL2 is overexpressed in many cancers and inhibition of extracellular LOXL2 impedes the formation of a tumor microenvironment. My PhD work focused on the contribution of LOXL2 secreted by stromal cells (endothelial cells and cancer associated fibroblasts) and tumor cells in clear cell renal cell carcinoma (ccRCC) angiogenesis. ccRCC is a highly vascularized and metastatic tumor. We showed that LOXL2 is expressed both by stromal and tumor cells in ccRCC and might play a specific role depending on its cellular origin in these tumors. Then we demonstrated that LOXL2 secreted by endothelial cells promotes angiogenesis in vitro and in vivo with a partial contribution of its catalytic activity. We also demonstrated that LOXL2 secreted by tumor cells stimulates angiogenesis in vitro and in vivo and that LOXL2 catalytic activity is involved in this process, notably modulating endothelial cells proliferation. Moreover, we showed that endothelial and tumor LOXL2 regulate several signaling pathways implicated in different steps of the angiogenic process.Both tumor and endothelial LOXL2 are involved in angiogenesis of ccRCC, in a dependent or independent catalytic activity manner
Lefebvre, Dominique. "Hexagallates de lanthanide pour matrices laser et substrats d'épitaxie : élaboration, étude cristallographique et spectroscopique." Paris 6, 1986. http://www.theses.fr/1986PA066415.
Frada, Jean-Michel. "Contribution à l'étude des multimatériaux acier-polymère-acier : caractérisation chimique et structurale des interphases dans des systèmes métal-oxyde-polymère." Nancy 1, 1992. http://docnum.univ-lorraine.fr/public/SCD_T_1992_0408_FRADA.pdf.
Loubière, Sophie. "Elaboration et caractérisation de poudres et de suspensions électrolytiques. Application à la fabrication de revêtements composites." Toulouse 3, 1996. http://www.theses.fr/1996TOU30209.
Miedzinski, Rafal. "Etude des effets optiques photo-induits dans les métallo-composites et analyse de leurs caractéristiques surfaciques par microscopie à force atomique." Reims, 2009. http://theses.univ-reims.fr/sciences/2009REIMS038.pdf.
MOUCHON, EMMANUELLE. "Composites ceramiques a matrice oxyde renforcee par des fibres longues tissees a proprietes thermiques et electromagnetiques specifiques : interet d'une voie d'elaboration sol-gel." Paris 6, 1993. http://www.theses.fr/1993PA066187.
Fontaine, Florian. "Composites à matrice carbone-oxyde et carbone-nitrure : thermodynamique de l'élaboration et son impact sur les propriétés physico-chimiques, thermiques et mécaniques des composites." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14217/document.
Carbon/carbon composites exhibit excellent mechanical and thermal properties at high temperature that make them espe-cially suitable for ablation or friction pieces. Their sensitivity toward oxidation above 400°C has lead to the will of doping them with refractory ceramics that are nonoxidizable or with a high oxidation temperature. The sol-gel process allowed to introduce 1 % in volume of titanium or aluminum oxide or nitride in the matrix. Nitrides are obtained by carbothermal nitridation of the oxide films. Two types of sols were used: the “standard” ones and those with extra sucrose. Sucrose is added to prevent pyrocarbon consumption during the nitridation. Furthermore, it was shown that it has an impact on the nitridation rate. Charged composites are then densified by Chemical Vapor Infiltration, which induces phases transforma-tions that were predicted by thermodynamics: titanium nitride films are partially carburized (formation of titanium carbonitride) and titanium dioxide films are reduced (formation of titanium oxycarbide). Aluminum-based films are more stable and don’t undergo any transformation. Thermal diffusivity of the as-synthesized composites is not much modified by the addition of these ceramics while the tensile and compressive strength are slightly increased. By the way, composites are hardened. Their oxidation kinetics is slowed down. Aluminum-rich composites exhibit a weight loss divided by two compared to the C/C reference. All those properties are directly, or not, linked to the composition of the sols, in particular to their sucrose content. Indeed, it was shown that sucrose-containing sols rather jellify on the surface of the composite, thus preventing the diffusion of precursor gases to the heart of the pieces. The final porosity is then modified. The porosity has an important impact on the compressive strength, thermal diffusivity and oxidation kinetics of the synthesized composites
Rul, Sébastien. "Synthèse de composites nanotubes de carbone - métal - oxyde à partir de mousses céramiques." Toulouse 3, 2002. http://www.theses.fr/2002TOU30189.
Nualas, Florence. "Fonctionnement en oxydation de matériaux composites céramiques (CMC) dans des environnements aéronautiques." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00993488.
Novikova, Anastasiia. "Nanofils ferromagnétiques en matrice de CeO2 et de SrTiO3 : de la compréhension de la structure locale aux propriétés magnétiques." Thesis, Versailles-St Quentin en Yvelines, 2015. http://www.theses.fr/2015VERS024V/document.
This PhD thesis is dedicated to the structural and magnetic studies of self-assembled ferromagnetic nanowires with diameters of 2-7 nm embedded in CeO2 (or SrTiO3) thin films grown on SrTiO3 (001) substrates.By means of X-rays Absorption Spectroscopy (XAS) and Vibrating Sample Magnetometry (VSM) Co, Ni and CoNi nanowires are studied. This study shows that at ambient temperature and pressure cobalt nanowires may contain Co-hcp or Co-fcc phase, while adding Ni stabilizes the fcc.This study also discusses structural and magnetic stability as a function of temperature under different thermal treatments. We describe in particular the effects of oxidative treatment followed by high vacuum annealing as a tool to tune the structure and magnetic properties of cobalt nanowires. XAS evidences linear dichroism in Ni and CoNi embedded nanowires of extremely small diameter (less than 2nm). We discuss possible origins of these phenomena considering the effects of strain and finite size of the objects.Finally, an essay of growing CeO2 or SrxBayTiO3 thin films doped by Fe is presented. It shows that within the CeO2 matrix no nanowires are evidenced by TEM, while XAS shows a large variety of different iron oxides even if the growth conditions are not drastically modified from one sample to another. As it is suggested by the magnetic measurements (hysteresis and anisotropy), formation of nanowires in SrxBayTiO3 matrix is very likely and the nanowires composition determined by XAS evidences a mixture of αFe and FeO phases
Cordier, Anne. "Élaboration de mousses nanocomposites nanotubes de carbone-métal-oxyde par synthèse CCVD de NTC in-situ dans des mousses céramiques." Toulouse 3, 2005. http://www.theses.fr/2005TOU30264.
The CCVD synthesis of CNT consists on selectively reduced a solid solution at a high temperature, in H2-CH4 atmosphere, in order to produce metal nanoparticules which immediately catalyse the decomposition of CH4 and allows the formation of CNT. The conditions of a-Al1. 8Fe0. 2O3 combustion synthesis were correlated to the oxide powders characteristics. The CNT were prepared by CCVD of a self-supported a-Al1. 8Fe0. 2O3 foam. The carbon quality was improved by Mo addition to the catalytic material during its synthesis or by Mo impregnation of a ceramic foam. It was shown that Mo favours the catalytic decomposition of CH4. The introduction under pressure of a viscous slurry of a-Al1. 8Fe0. 2O3 into consolidated commercial foams was developed. The NTC quantity is increased using a slurry of Mg0. 9(Co0. 75Mo0. 25)0. 1O1+e. They offer a specific surface area of 15 m2/g of composite material, making it attractive as a support of nanoparticules
Besse, Marie. "Caractérisation des interactions des nanoparticules de dyoxyde de titane avec les interfaces biologiques." Compiègne, 2012. http://www.theses.fr/2012COMP2039.
Nanoparticles (NPs) have unique properties due to their small size (less than 100 nm). Titanium dioxide NPs (TiO2 NPs) are widely used by the industrial sector for the manufacture of products such as sunscreens, paints, chocolates and air filters. Nowadays, it is known that Human are daily exposed to TiO2 NPs but their impact on health and potential toxicity mechanisms still unclear. Therefore, we studied the TiO2 NPs interaction with the biological interfaces and their components, i. E. Proteins and lipids. Biological membranes were studied using model membranes mimicking the lipid composition of the pulmonary surfactant and the cell membrane. Our results showed that TiO2 NPs deeply disturb the lipid distribution and increase the membrane order which lead to a modification of the physical state of the membrane. This could seriously disturb the membrane dynamic and function. Our work on TiO2 NPs interaction with proteins adsorbed on a surface revealed that proteins from the extracellular matrix (ECM) catch a lot more TiO2 NPs than serum proteins. Then, cell experiments showed that the presence of TiO2 NPs on a fibronectine layer (a major ECM protein) inhibits the adhesion of preosteoblastic cells. The adhesion step is required for various cell processes such as differentiation and proliferation. These conclusions are very important to consider since TiO2 NPs could be released from titanium bone implants into the surrounding tissue
Bahloul, Walid. "Génération in situ de dioxyde de titane par réactions d’hydrolysecondensations dans une matrice polymère fondu." Electronic Thesis or Diss., Lyon 1, 2010. http://www.theses.fr/2010LYO10124.
Polypropylene/Titanium dioxide (PP/TiO2) nanocomposites were prepared from an original method based on the hydrolysis-condensation reactions of titanium alkoxide inorganic precursor premixed with PP under molten conditions. The synthesis is based on sol-gel method without solvent through extrusion process. A second treatment in hot water was applied in order to improve final conversion degree. First, hydrolysis-condensation reactions of titanium n-butoxide precursor were studied in model medium. Based on a kinetic equation carried out in the model medium, then the synthesis of titanium dioxide particles was transposed and modelled in polypropylene medium with high molar mass. Chemical, structural and morphological analyses highlight the in situ synthesis of bactericides PP/TiO2 nanocomposites andpresenting a particular morphological and rheological behaviour
Cinausero, Nicolas. "Etude de la dégradation thermique et de la réaction au feu de nanocomposites à matrice PMMA et PS." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2009. http://tel.archives-ouvertes.fr/tel-00382965.
Aouadi, Merwen. "Composites "Oxydes nanostructurés-analogue du bleu de Prusse" : nouveau matériau pour le stockage de l'information." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00829109.
Chayani, Moncef. "Spéficité structurale et propriété d'oxyde de silicium déposé par procédé plasma." Toulouse 3, 2003. http://www.theses.fr/2003TOU30091.
Legorreta, Garcia Felipe. "Nanocomposites nanotubes de carbone-métal-oxyde : synthèse par CCVD et frittage par SPS." Toulouse 3, 2007. http://www.theses.fr/2007TOU30117.
The first objective was to study the preparation of CNT-metal-ZrO2 nanocomposite powders by the carbon nanotubes (CNT) in situ synthesis method. The conditions for the combustion synthesis of solid solutions between zirconia and one or several oxides of iron, cobalt, molybdenum or yttrium have been established. All solid solutions were obtained in stabilised form, either tetragonal or cubic, but yttrium incorporation was necessary to ensure a suitable thermal stability. Their selective reduction in either H2, or H2-CH4 or H2-C2H4 was studied in order to form metal-ZrO2 powders or CNT-metal-ZrO2 powders, respectively. The second objective was to study the consolidation and densification by spark-plasma-sintering of the ZrO2-matrix nanocomposite powders and of double-walled CNT-Co/Mo-MgO model powders. The mechanical properties and the electrical conductibility were measured
Pastre, Sybille. "Etude prospective et compréhension physico-chimique des renforts pour matériaux composites à base métallique argent dans les appareils électriques." Lille 1, 2005. http://www.theses.fr/2005LIL10153.
The present work is part of a collaboration between Schneider Electric (CIFRE fundings) and the Laboratoire de Cristallochimie et Physico-chimie du Solide in Villeneuve d’Ascq. The aim was to better understand and to improve the physicochemical properties of tin dioxide based ceramics use as a reinforcement in electric contacts made of metallic silver matrix. Indeed, electric contacts can be damaged by thermomechanical constraints, thus leading to a deterioration of the properties. The development of CuO doped Sn02 reinforcement using two different methods of synthesis (Pechini and attrition) allows to obtain powders with particle size lower than the micron. Surface analysis of powders (so called Pechini) shows a migration of copper, in its two valence states, towards the surface of Sn02 particles, whereas with powders resulting from attrition, the copper, in the form CuO, is located at the particles surface of Sn02. The use of such powders, obtained with both methods improves the densification of sintered reinforcements at 933°C. The study is carried on with Sb203 which improves the electric conductivity of CuO doped Sn02 reinforcement. Composite materials made of fine reinforcement powders presents not only a microstructure which is more homogeneous, but alsoa better sintering capability than those elaborated with coarse-grained powders. Finally, the manufacture of fine powders has the consequence of an increase of the Vickers hardness and of clearly improving the performance of the contacts, during electrical tests, especially when it is damaged by the welding process