Thèses sur le sujet « Substrats structurés »
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Bugnicourt, Ghislain. « Adhésion, croissance et polarisation de neurones sur substrats micro-et nano-structurés ». Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00665074.
Texte intégralNi, Xiaofang. « Culture et différenciation cellulaire sur des substrats structurés et dans des dispositifs microfluidiques ». Paris 6, 2009. http://www.theses.fr/2009PA066666.
Texte intégralAssaud, Loic. « Fonctionnalisation de substrats nano-structurés pour la conversion et le stockage de l'énergie ». Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4049.
Texte intégralIn order to meet the growing needs in today's society that requests more transportation and portable devices, energy production, conversion and storage systems are now experiencing real changes. To fabricate systems able to generate a controlled and renewable energy, nanoscience and nanotechnology are leading research fields. The work presented in this manuscript describes the fabrication of nanosized, large-scale organized structures. These nanostructures have been functionalized through film and particle synthesis using a chemical vapor deposition method: the Atomic Layer Deposition (ALD).Thus, metal/insulator/metal (MIM) systems are fabricated on highly-ordered high-aspect ratio porous alumina. The materials that have been deposited are TiN, Al2O3 and HfO2. The aim is to produce high performance nanocapacitors that can be used for data storage (DRAM) application or for energy storage in small devices such as RFID.In a second part, metallic catalysts such as Pd/Ni have been deposited on alumina membranes for formic acid electro-oxidation. Similarly, TiO2 nanotubes have been fabricated by anodic oxidation and they have been functionalized with Pd nanoparticles for ethanol electro-oxidation. Both studied systems can be used as anode catalysts in direct liquid fuel cells.Finally, the last part of this work has consisted in the study of Cu2O, as a p-type semiconductor, that has been electrochemically deposited onto TiO2 nanotubes (n-type semiconductor). The resulting p/n junction can be interesting for solar energy photoconversion
El, Khoury Maroun Michel. « Croissance de GaN semipolaire par épitaxie en phase vapeur aux organométalliques sur substrats de Si structurés ». Thesis, Nice, 2016. http://www.theses.fr/2016NICE4001.
Texte intégralTo-date, commercial III-nitride optoelectronic devices are grown along the c-direction, which suffers two intrinsic limitations. The first is the strong polarization discontinuities across nitride hetero-interfaces that are responsible for the quantum confined Stark effect, leading in the case of GaN-based optical devices to electron-hole wave function separation within the quantum wells, and thus, a decrease in the oscillator strength. The associated longer exciton lifetime together with the occurrence of non-radiative defects, result in reducing the device's efficiency. The second is the indium incorporation on the polar plane, which is relatively limited when compared with its incorporation on other crystallographic orientations. These deleterious effects can be partially overcome by performing the growth of GaN on planes other than (0001), such as semipolar ones leading to the eventual improvement of devices' performances. Growth of device-quality semipolar GaN, however, comes at a price, and the only currently available option is homoepitaxy, which is limited in size and is highly priced. At this point, the growth on foreign substrates becomes appealing, especially on silicon. In this thesis, the MOVPE growth of (10-11) and (20-21) semipolar GaN on patterned silicon substrates has been performed. The general fabrication strategy, which consists of patterning the appropriate silicon wafer orientation in order to reveal the Si (111) facets, will be first described. Subsequently, the selective growth of GaN along the c-direction will be carried out, where the c-oriented crystals will be brought to coalescence until a semipolar layer is achieved
Richard, Marie-Ingrid. « Étude in situ et ex situ par rayonnement synchrotron de la croissance d’îlots de GE sur substrats de Si (001) nominaux et pré-structurés ». Grenoble 1, 2007. http://www.theses.fr/2007GRE10318.
Texte intégralThe work presented in this manuscript focuses on the structural (size, strain, defects, composition) investigation of Ge nano-islands grown on both nominal and pre-pattemed Si(OOI) substrates by Molecular Bearn, using grazing incidence (anomalous) X-ray diffraction and scattering at ESRF. The samples were either prepared in independent MBE chambers and then characterized ex situ on the IDOI ESRF beamline, or they were characterized in situ during their MBE growth, using the BM32 ESRF beamline setup. The dynamical scattering effects occurring in grazing incidence have been studied on the basis offinite element simulations of the strain fields in nano-islands. A novel X-ray method has been developed to detect the presence of defects and to study the structure oftheir core by concentrating on measurements along rods of scattering by defects passing through bulk forbidden reflections. To obtain new insight into the dynamics of growth phenomena, the shape, size, growth mode, composition and possible defects and/or atomic ordering inside aIl islands were characterized, as a function of deposition, deposition temperature, flux and possible annealing. The evolution ofstrain, the transition from elastic to plastic relaxation, the intermixing and the correlation ofthese internaI parameters with the different morphologies of the island have been addressed using in situ scattering methods. At last, the growth on nominal and patterned Si(OO 1) surfaces were compared, showing that by tuning the surface curvature, it is possible to change the relaxation state and the overaIl elastic energy of islands without modifying their mean Ge composition
Selmi, Mayada. « Textures à la surface libre de cristaux liquides smectiques : étude en géométrie films librement suspendus et sur substrats structurés ». Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0098/document.
Texte intégralThe present work is an experimental study of the textures that appear in the meniscus of free standing smectic films with thermotropic liquid crystals. These complex fluids serve as model systems to investigate elasto-capillary phenomena which, under certain conditions, manifest themselves through periodic deformations of the liquid crystalair interface. In the first part of the thesis, we focus our attention on meniscus structures whose interfacial topographies are thoroughly characterized thanks to an in-house optical interferometry technique. Our study allows us to identify the main parameters involved in the development of meniscus structures and to discuss the physical mechanisms that are likely to be responsible for their formation. In particular, we show how a phase transition-induced layer shrinkage triggers a mechanical instability leading to interfacial undulations of the smectic free surface. In the second part of the manuscript, we address the case of thin liquid crystal films deposited on solid patterned solid substrates. The latter consist of regular arrays of microposts fabricated through photolithographic techniques. Such a geometry allows a meniscus to be formed around each micropost and makes it possible to examine the influence of other parameters such as the anchoring conditions on the solid substrate. The results gathered so far are able to shed some light on the characterization and the understanding of the specific deformations and textures that appear in the menisci of complex fluids
Richard, Céline J. E. « Phénomènes de mouillage aux petites échelles sur des substrats non structurés et structurés : films minces de cristaux liquides et propriétés de mouillage des liquides ioniques aux petites échelles ». Phd thesis, Université Pierre et Marie Curie - Paris VI, 2011. http://tel.archives-ouvertes.fr/tel-00662524.
Texte intégralFadel, Christy. « Influence of the Al content on the structure, optoelectronic properties and electronic structure of AZO transparent electrodes deposited by HiPIMS for solar energy conversion ». Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0080.
Texte intégralIn this work, the influence of Al (Aluminum) dopant concentration on the properties of Al-doped ZnO (AZO) films synthesized by reactive High Power Impulse Magnetron Sputtering (HiPIMS), and deposited from Zn/Al targets with 1, 2, 5, 10 or 15 at.% Al is studied. It is observed that the Al content has a strong influence on the reactive sputtering process, as it is easier to sputter-deposit at high rates from targets containing lower Al contents. This is explained by the high reactivity of Al towards oxygen, which easily poisons the target surface with Al oxide more difficult to etch upon bombardment by ions from the plasma phase. Films have been synthesized in the 0.56-14.71 at.% Al range, where the film structure and microstructure evolves from nanocrystalline columnar films towards ultrafine nanocrystalline films of wurtzite ZnO structure upon increasing the Al content. The electrical properties revealed that effective doping may be achieved up to 3 at.% Al by using HiPIMS. And most importantly, it is found that electronic structure measurements contain signatures of dopant activation and segregation that may serve to investigate on the origin of electrical properties degradation and to optimize the electrical properties of AZO films. Finally, flat or structured glass/AZO/ZnO/Cu₂O/Au thin film stacks were made. The patterning was done by ultrashort pulsed direct laser interference patterning, and the morphology and microstructure are presented together with possible strategies to improve the preliminary electrical results
Garcia, Pardo Javier. « Structural and functional characterization of regulatory metallocarboxypeptidases : Studies on human carboxypeptidases D and Z, and the transthyretin-like domain ». Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/319703.
Texte intégralMetallocarboxypeptidases (MCPs) are zinc-dependent enzymes that cleave single amino acids from the C termini of proteins and peptides. The first MCP to be identified was carboxypeptidase A1 (CPA1), a pancreatic enzyme that removes C-terminal hydrophobic residues. In the ensuing decades since the discovery of CPA1, dozens of additional MCPs have been found in different extra-pancreatic tissues and fluids, comprising a wide range of physiological roles ranging from digestion of food to the production of neuropeptides and peptide hormones and the selective processing of tubulin. The present thesis has the aim to gain insights into the knowledge of the structure and biological functions of two regulatory MCPs. For this purpose, we applied a wide range of biochemical approaches to elucidate biological activities of human carboxypeptidases D and Z. Furthermore, we decided to study for the first time the structure and roles of the transthyretin-like (TTL) domains found in all members of this subfamily of proteases, taking as example the first TTL domain belonging to the first catalytic domain of human carboxypeptidase D (termed here as h-TTL). The first chapter describes the amyloid formation under physiological conditions by h-TTL and unravels that the monomeric transthyretin fold has an inherent propensity to aggregate due to the presence of preformed amyloidogenic structural elements. The aggregation mechanism described in this work for a natively monomeric transthyretin-like protein, is being found also in a number of initially soluble globular proteins associated with protein deposition diseases and might be in fact quite generic for folds displaying preformed amyloidogenic elements in their structures, essentially β-sheets. The second chapter presents the crystal structure solved at ultra-high resolution of the h-TTL described in the first chapter. The information derived in the present study might facilitate the understanding of the biological roles of the TTL domains found in M14B subfamily members and would be an interesting tool to analyze in detail the structural properties and the folding mechanisms of these domains. The third chapter comprises the characterization of the substrate specificity of human carboxypeptidase D by using a combination of quantitative peptidomic approaches. This unique enzyme with multiple catalytic sites might be implicated in the processing of neuropeptides and growth factors. Thereby, the study of its mechanism of action is of significant importance for biomedicine. The fourth chapter describes de development of a simple and inexpensive method to improve protein production of heparin-affinity carboxypeptidases using mammalian cells, taking as example the case of carboxypeptidase Z. The purified protein is enzymatically active and can be used for high-throughput functional and structural studies. The fifth chapter applies several quantitative peptidomic approaches to characterize the substrate specificity of the human carboxypeptidase Z. Furthermore, this work provides the modelling of its catalytic domain, as well as of their frizzled-like domain, in order to analyze their role in Wnt signaling.
Chaban, Nicolas. « Ingénierie des contraintes de films minces d'oxydes de LaNiO3 : les substrats piézoélectriques ». Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00721808.
Texte intégralChauve, Marie. « Modélisation cinétique de l'hydrolyse enzymatique des substrats cellulosiques. Influence de la structure et morphologie du substrat ». Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00680091.
Texte intégralRichter, Andreas. « Structure formation and fractionation in systems of colloidal rods ». Phd thesis, Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2007/1309/.
Texte intégralRomagna, Pinter Patricia. « Reappraising the Numidian system (Miocene, southern Italy) deep-water sandstone fairways confined by tectonised substrate ». Thesis, University of Aberdeen, 2017. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=238534.
Texte intégralKawwam, Mohammad. « Pulsed Laser Deposition and Structural Analysis of Crystalline CuO and GaN Thin Films ». Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10007.
Texte intégralThe thesis presents experimental results related to the Pulsed Laser Deposition (PLD) of GaN and CuO thin films using sapphire, SrTiO3, quartz and MgO substrates. The evolution of crystallization and surface morphology of the as-deposited films were studied to investigate the influence of the process conditions such as: substrate heating, background pressure, target-substrate distance, laser energy density, and substrate location, which were systematically varied. The as-deposited films were characterized by X-ray diffraction, atomic force microscopy and scanning electron microscopy, X-ray photoelectron spectroscopy, RHEED and RAMAN techniques. The results convincingly demonstrate that the enhancement in film growth quality - the reduction in roughness and the delay of epitaxial breakdown - is related to the control of PLD species kinetics. The films thickness, crystallinity, homogeneity and surface roughness are strongly dependent on deposition conditions
Helbig, Ralf, Denise Günther, Jens Friedrichs, Florian Rößler, Andrés Lasagni et Carsten Werner. « The impact of structure dimensions on initial bacterial adhesion ». Royal Society of Chemistry, 2016. https://tud.qucosa.de/id/qucosa%3A35958.
Texte intégralStefanou, Stefanos. « Design, fabrication and characterisation of advanced substrate crosstalk suppression structures in silicon on insulator substrates with buried ground planes (GPSOI) ». Thesis, University of Southampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268642.
Texte intégralBugyik, Paul L. « Coplanar waveguide structures on micromachined glass substrates ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62700.pdf.
Texte intégralEngelman, Zoar Jacob. « Arrhythmic substrates in structural heart disease ». Thesis, University of Auckland, 2011. http://hdl.handle.net/2292/9508.
Texte intégralPégeot, Henri. « Étude des gluthation transférases de la classe Phi du peuplier (Populus trichocarpa) : caractérisation structurale, enzymatique et recherche de molécules cibles ». Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0242/document.
Texte intégralGlutathione transferases (GSTs) belong to a multigenic family whose presence in most eukaryotes, prokaryotes and archaea reflects their widespread nature and very likely important functions. These enzymes represent a major group of enzymes involved in xenobiotic detoxification and secondary metabolism. From the most recent genomic and phylogenetic analyses, the GST family is subdivided into 14 classes that can be separated into two main groups based on the catalytic residue which is either a serine (Ser-GST) or a cysteine (Cys-GST). Ser-GSTs usually catalyze glutathione (GSH) conjugation and/or peroxide reduction. On the other hand, Cys-GSTs cannot perform GSH-conjugation reactions but instead catalyze thiol-transferase, dehydroascorbate reductase and deglutathionylation reactions. Ser-GSTs from the Phi class (GSTF) are present in photosynthetic organisms and some basidiomycetes. This class is composed of a large number of genes compared to other GST classes which are amongst the most stress-inducible. The corresponding proteins have been extensively studied in crops with regard to their detoxification activities toward herbicides. However, with a few exceptions, very little is known about their roles in planta and it is not well understood why this class has expanded. By combining molecular, cellular, biochemical and structural approaches, the eight isoforms from the model tree Populus trichocarpa have been characterized during this PhD project. Phylogenetic analysis of GSTFs in the green lineage shows that the apparition of this class is concomitant with the appearance of terrestrial plants and that different groups can be distinguished based on the active site signature. RT-PCR analysis of the eight isoforms of GSTFs showed that transcripts mostly accumulate in female flowers, petioles and fruits. Some aspects of the reaction mechanism have been characterized by determining kinetic parameters of the eight poplar GSTFs and of several mutated variants for key residues towards model substrates. The structures of five GSTFs have been solved and these dimeric proteins display a typical GST fold but specificities have been observed at the catalytic site level. Moreover, considering the demonstrated capacity of GSTF orthologs to bind hormones, anthocyanins or flavonoids, and the consistent high expression of poplar GSTFs in female flowers and fruits, two organs rich in these molecules, we speculate that they may also possess ligandin properties. Preliminary results have been obtained regarding the nature of the substrates in various poplar organs by analyzing protein thermostability in the presence of putative ligands. In order to assess whether a functional redundancy between poplar Phi GSTs exists and to identify their mode of action (catalytic vs ligandin functions), we started to isolate and identify physiological substrates
Tick, T. (Timo). « Fabrication of advanced LTCC structures for microwave devices ». Doctoral thesis, University of Oulu, 2009. http://urn.fi/urn:isbn:9789514292507.
Texte intégralNagpal, Akanksha. « Crystal Structures of Nitroalkane Oxidase : Insights into the Structural Basis for Substrate Specificity and the Catalytic Mechanism ». Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-07172005-152826/.
Texte intégralDr. Allen M. Orville, Committee Chair ; Dr. Loren D. Williams, Committee Member ; Dr. Donald F. Doyle, Committee Member ; Dr. Dale E. Edmondson, Committee Member ; Dr. Giovanni Gadda, Committee Member.
König, Rodrigo. « CHIRONOMIDAE (DIPTERA : INSECTA) NA MICROBACIA HIDROGRÁFICA DO RIO VACACAÍ-MIRIM (SANTA MARIA, RS) ». Universidade Federal de Santa Maria, 2009. http://repositorio.ufsm.br/handle/1/5263.
Texte intégralThe Chironomidae family constitutes one of the main groups of aquatic insects, being present in a great variety of environments and participating of various ecological processes, such as nutrients cycle and energetic transference. In the south region of the country, few studies are addressed to this community, not existing works in the region of Santa Maria, in the state of Rio Grande do Sul. Aiming to contibute for the knowledge of the group, this work had as goal to study the Chironomidae fauna in different environments in the Vacacaí-Mirim river microbasin, analyzing the composition and structure of the community in function of the physical, chemical, morphometric and environmental characteristics related to substrata. In December of 2007, the Chironomidae larvae were collected with a Surber sampler, in four locations along the Vacacaí-Mirim river, including the different present substrata. Alongside, some non-biotic variables of these locations were measured. The organisms were sorted and identified in the laboratory up to the level of genus, and based on these data, it was verified, in the locations and substrata, the absolute and relative density of these genera and subfamilies and the taxonomic richness, Shannon diversity and Equitability of these locations, besides the separation of the fauna in different substrata in functional feeding groups. The composition was compared by the multivariate statistics (grouping and variance analyses) and the community structure and substrata (richness, groups density, diversity and equitability) compared by the analysis of variance. The most representative subfamily was the Chironominae, followed by Orthocladiinae and Tanypodinae. Differential composition was observed among all the locations: points A and B were less altered physical-chemically, obtaining high diversity and more homogeneous distribution of the genera. In B, the greater habitats heterogeneity is responsible for the presence of exclusives taxa and for the high taxonomic richness. In C and D, the agricultural activities close to the water body are possibly responsible for the higher concentrations of nutrients and total solids found, resulting in the dominance of groups more tolerant to such conditions, mainly Rheotanytarsus. Sand samples presented lower density and richness, since this is a naturally poorer substratum. Rocks also sheltered a lower quantity of Chironomidae. In mixed or vegetation composed substrata, which present higher energetic availability and shelter conditions, higher densities were found. The physical-chemical and morphometric factors were more influent in the fauna structure determination than the substrata, which only complemented the ecological requirements of the groups. In general, few associations among the subfamilies and the feeding groups to the substrata were found.
A família Chironomidae constitui um dos principais grupos de insetos aquáticos, estando presente em uma grande variedade de ambientes e participando de vários processos ecológicos, como a ciclagem de nutrientes e transferência energética. No Sul do país, poucos estudos são direcionados a esta comunidade, não existindo trabalhos na região de Santa Maria, RS. Visando contribuir para o conhecimento do grupo, este trabalho objetivou estudar a fauna de Chironomidae em diferentes ambientes da microbacia do rio Vacacaí-Mirim, analisando a composição e estrutura da comunidade em função das características ambientais físicas, químicas, morfométricas e relacionadas ao substrato. No mês de dezembro de 2007, as larvas de Chironomidae foram coletadas com um amostrador Surber, em quatro locais ao longo do rio Vacacaí-Mirim, com diferentes características ambientais. Foram contemplados os diferentes substratos presentes. Juntamente, foram mensuradas algumas variáveis abióticas dos locais. Os organismos foram triados e identificados em laboratório até nível de gênero e, com esses dados, foram verificados, nos locais e substratos, a densidade absoluta e relativa dos gêneros e das subfamílias e a riqueza taxonômica. Diversidade de Shannon e Equitabilidade dos locais, além da separação da fauna dos diferentes substratos em grupos alimentares funcionais. A composição foi comparada através de estatística multivariada (análises de agrupamento e de variância) e a estrutura das comunidades e substratos (riqueza, densidade dos grupos, diversidade e equitabilidade) comparadas por análise de variância. A subfamília mais representativa foi Chironominae, seguida por Orthocladiinae e Tanypodinae. Foi observada diferença de composição entre todos os locais: os pontos A e B estiveram menos alterados físico-quimicamente, obtendo elevada diversidade e distribuição mais homogênea dos gêneros. Em B, a maior heterogeneidade de hábitats é responsável pela presença de táxons exclusivos e pela alta riqueza taxonômica. Em C e D, as atividades agrícolas próximas ao corpo hídrico possivelmente são responsáveis pelas maiores concentrações de nutrientes e de sólidos totais encontradas, resultando na dominância de grupos mais tolerantes a tais condições, principalmente Rheotanytarsus. Amostras de areia apresentaram menor densidade e riqueza, por este ser um substrato naturalmente mais pobre. Rochas também abrigaram uma menor quantidade de Chironomidae. Em substratos compostos por vegetação ou mistos, que possuem maior disponibilidade energética e condições de abrigo, foram encontradas densidades mais elevadas. Os fatores físico-químicos e morfométricos foram mais influentes na determinação da estrutura da fauna do que os substratos, os quais apenas complementaram as exigências ecológicas dos grupos. No geral, foram encontradas poucas associações das subfamílias e grupos alimentares com os substratos.
Guptah, Vinod Kumar. « Growth on patterned substrates for optoelectronic device applications ». Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267027.
Texte intégralGhaddar, Kassem. « Structural analysis of yeast amino acid transporters : substrate binding and substrate-induced endocytosis ». Doctoral thesis, Universite Libre de Bruxelles, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209318.
Texte intégralIn this work we combined computational modeling and yeast genetics to study substrate binding by yAAPs and the endocytosis of these transporters in response to substrate transport. In the first part of this work, we analyzed the selective recognition of arginine by the yeast specific arginine permease, Can1. We constructed three-dimensional models of Can1 using as a template the recently resolved structure of AdiC, the bacterial arginine:agmatine antiporter, which is also a member of the APC superfamily. By comparison of the binding pockets of Can1 and Lyp1, the yeast specific lysine permease, we identified key residues that are involved in the recognition of the main and side chains of arginine. We first showed that the network of interactions of arginine in Can1 is similar to that of AdiC, and that the selective recognition of arginine is mediated by two residues: Asn 176 and Thr 456. Substituting these residues by their corresponding residues in Lyp1 converted Can1 into a specific lysine permease. In the second part of this work, we studied the regulation of two permeases, Can1 and the yeast general amino acid permease, Gap1. In the presence of their substrates, Gap1 and Can1 undergo ubiquitin-dependent endocytosis and targeting to the vacuolar lumen for degradation. We showed that this downregulation is not due to intracellular accumulation of the transported amino acids but to transport catalysis itself. By permease structural modeling, mutagenesis, and kinetic parameter analysis, we showed that Gap1 and Can1 need to switch to an intermediary conformational state and persist a minimal time in this state after binding the substrate to trigger their endocytosis. This down-regulation depends on the Rsp5 ubiquitin ligase and involves the recruitment of arrestin-like adaptors, resulting in the ubiquitylation and endocytosis of the permease.
Our work shows the importance of the structural analysis of yAAPs to get further insight into the different aspects of their function and regulation. We validate the use of a bacterial APC transporter, AdiC, to construct three-dimensional models of yAAPs that can be used to guide experimental analyses and to provide a molecular framework for data interpretation. Our results contribute to a better understating of the recognition mode of amino acids by their permeases, and the regulation of this transport in response to substrate binding.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Silva, Sembukuttiarachilage Ravi Pradip. « Electronic, optical and structural properties of semiconducting diamond-like carbon thin films ». Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319523.
Texte intégralOsborn, Dawn Alexandra. « Rocky intertidal community structure on different substrates / ». Diss., Digital Dissertations Database. Restricted to UC campuses, 2005. http://uclibs.org/PID/11984.
Texte intégralAlkhalaf, Lona M. « Structure, function and substrate tolerance of TxtC ». Thesis, University of Warwick, 2013. http://wrap.warwick.ac.uk/60151/.
Texte intégralHargreaves, Martin Bernard. « Substrate structure activity relationships of cytochrome P4502E1 ». Thesis, University of Leicester, 1995. http://hdl.handle.net/2381/35247.
Texte intégralPauthe, Emmanuel. « Approches cinétiques et moléculaires de la reconnaissance enzyme-substrat : application à l'étude de l'activité protéolytique de la thermolysine ». Compiègne, 1998. http://www.theses.fr/1998COMP1139.
Texte intégralMayer, Suzanne Marie. « X-ray structure determination of Klebsiella pneumoniae nitrogenase component 1 ». Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323342.
Texte intégralDeboucq, Julien. « Caractérisation ultrasonore de structures à couche et à gradient de contraintes par ondes de surface haute fréquence générées par capteurs MEMS de type IDT -SAW ». Thesis, Valenciennes, 2012. http://www.theses.fr/2012VALE0017/document.
Texte intégralThe use of coatings and thin layers deposited on substrates is highly sought in many applications. The objectives of these coatings and deposits are multiple (improve the durability of structures, their wear resistance and fatigue, etc.). On the other hand, gradient materials are being developed to meet new functional requirements, such as a better resistance to temperature, wear and corrosion. For all of these applications, the characterization of these coatings and gradient materials, in order to determine their properties (thickness, elastic constants, adherence, residual stresses, etc…), is decisive for the health control of pieces and for their optimum operation during their use. To characterize these structures, wechose to exploit the dispersion of surface acoustic waves over a wide frequency range (10 to 60 MHz).To excite these waves, SAW-IDT MEMS sensors have been carried out at different frequencies covering the entire frequency range we considered. The quasi-harmonic excitation was preferred to obtain accurate measures of phase velocities. We showed the potential of this approach by characterizing, first, thin layers structures (500 nm) and second, amorphous structures with a stressesgradient
Diaz, J. A. D. « Nano-structured substrates for surface-enhanced Raman scattering ». Thesis, Queen's University Belfast, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431606.
Texte intégralLey, Marc. « Cellule photovoltai͏̈que MIND-amélioration du rendement quantique interne à l'aide d'une sous-structure active enterrée dans l'émetteur ». Université Louis Pasteur (Strasbourg) (1971-2008), 2002. http://www.theses.fr/2002STR13212.
Texte intégralPhotovoltaic solar cells that convert solar light into electricity would represent a clean and inexhaustible energy source for the future on the condition of a breakthrough in comparison with today's devices performances. In this work, we concentrate on aspects able to raise the photovoltaic conversion efficiency above the limitations of present cells and make solar energy competitive with conventional energy sources. The first part of the study is devoted to new theoretical ideas considered as 3rd generation of photovoltaics. More precisely, we investigate the use of an intermediate energy band and the exploitation of low-energy-threshold impact ionisation. Next, we study elements of realisation of model silicon solar cells capable to function according to the preceding ideas and fabricated on the basis of an original concept by ion implantation followed by a thermal treatment. They represent an intermediate step towards a final photovoltaic cell and have been characterised by different techniques in specialized laboratories. We exploit theoretically and experimentally a continuous substructure in the emitter. It induces a dead zone separated from the bulk by a minority carrier collection limit. It is then easy to quantify the light flux absorbed in the active zone and determine with a sufficiently good precision the zones with new optoelectronic properties. Effects never mentioned before have been observed. A deeper analysis of the experimental collection efficiency of the active device zone shows an increased absorbance in the amorphised zone produced by the implantation and in the recrystallized layers submitted to a local mechanical stress field. On the basis of the collection theory and an auto-correlated calculation, we identify a fundamental increase of the internal quantum efficiency in the stressed recrystallised layers, which can be interpreted as the result of a low-energy carrier multiplication
Johnson, Christopher N. « Nucleic Acid Substrates : Investigation of Structural and Dynamic Features that Influence Enzyme Activity ». Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/chemistry_diss/59.
Texte intégralDikme, Yılmaz. « MOVPE and characterization of GaN-based structures on alternative substrates ». [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982157576.
Texte intégralGössl, Illdiko Maria. « Supramolecular structures of dendronized polymers and DNA on solid substrates ». [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968755925.
Texte intégralGössl, Illdiko Maria. « Supramolecular structures of dendronized polymers and DNA on solid substrates ». Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2003. http://dx.doi.org/10.18452/14893.
Texte intégralComplexes of oppositely charged polyelectrolytes play an important role in both biology and material science, for instance DNA condensation in vitro, nucleosomal structure, non-viral gene transfection systems as well as layer-by-layer adsorption. Although there are theories predicting overcharging of polyelectrolyte complexes, the driving forces are still under debate and systematic experimental studies on single polyelectrolytes remain challenging. Therefore the question arose if it is possible to analyze single polyelectrolyte complexes, using DNA and dendronized polymers, with the scanning force microscope in order to investigate the complexation in detail. For the complex analysis, the polyelectrolytes were allowed to interact in solution and then to adsorb on negatively charged mica or on mica coated with a positively charged polymer. Scanning force microscopy was used to investigate the adsorbed species. DNA/dendronized polymer complexes of charge ratio of 1/1 through 1/0.7 adsorbed on mica coated with a positively charged polymer. The analysis of high resolution molecular images indicated that DNA wraps around the dendronized polymer with an estimated pitch of (2.30 ± 0.27) nm and (2.16 ± 0.27) nm for dendronized polymers of generation two and four, respectively. In the proposed model the polyelectrolyte with the smaller linear charge density is wrapped around the more highly charged dendronized polymer, resulting in a negatively overcharged complex. This overcharging is consistent within recent theories of spontaneous overcharging of complexes of one polyelectrolyte wrapping around the other. Using the complex of DNA and dendronized polymers of second generation, the influence of monovalent salt concentration on the molecular structure was studied. By increasing the salt concentration the pitch showed a minimum as predicted by the interplay of electrostatic forces and entropic interactions of polyelectrolyte adsorption. At high salt concentration (2.4 M NaCl) the release of DNA from the complex can be observed. The results showed that the DNA/dendronized polymer system can be used as a new, high potential model system to investigate single polyelectrolyte interactions. With regard to recent theories, the experimental results indicate that the overcharging of the complex is mainly driven by electrostatic forces whereas contributions of counterion entropy and bending energy seem to be negligible. This understanding may be useful for the design of single polyelectrolyte complexes for non-viral gene delivery systems and might help to optimize the transfection efficiency based on the structure of the vector system.
Ismail, Alhzzoury Ahmad. « Contribution à la modélisation des structures SIW et SINRD pour application micro-ondes et télécommunication ». Phd thesis, Toulouse, INPT, 2013. http://oatao.univ-toulouse.fr/9701/1/ismail_alhzzoury.pdf.
Texte intégralWang, Huanchen Ke Hengming. « Structural studies on substrate and inhibitor selectivity of phosphodiesterases ». Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2006. http://dc.lib.unc.edu/u?/etd,283.
Texte intégralTitle from electronic title page (viewed Oct. 10, 2007). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Biochemistry and Biophysics." Discipline: Biochemistry and Biophysics; Department/School: Medicine.
Casale, Marco. « Réalisation d'un laser DFB hybride sur substrat de verre ». Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT011/document.
Texte intégralThe current needs of optical telecommunications and sensors require developing integrated optical circuits providing different and heterogeneous functions on the same substrate. The main issue is the incompatibility between the manufacturing processes of these optical functions. This work deals with the integration of active (emission, amplification) and passive (multiplexing, filtering, etc.) functions on a passive glass substrate. Its aim is to develop a DFB three-dimensional hybrid laser by ion-exchange in passive glass. This laser is made of a Bragg channel waveguide, selectively buried in the passive glass substrate, loaded by a plane waveguide, defined at the surface of an Er3+:Yb3+ codoped active glass wafer. It emits a (420±15) µW laser signal at 1534 nm for (390±20) mW injected pump power. Hence this device opens the way towards the integration of active functions, located at the surface of the passive glass substrate, with passive ones, spreading at its surface and in its volume
Marechal, Nils. « Étude structurale des protéine arginine méthyltransférases : reconnaissance des substrats et conception rationnelle de modulateurs ». Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAJ048.
Texte intégralProtein arginine methyltransferases (PRMT) are involved in many cellular processes, including gene expression regulation, splicing control, maintenance of genome integrity and signal transduction.Since deregulation of those biological processes appears to be implicated in the pathogenesis of different diseases, PRMTs have emerged as potential new targets for the development of novel therapeutic modulators. Despite the large amount of biological and structural data on PRMTs, two challenges remain to be solved by structural biology ; (I) understanding how PRMTs recognize and bind their full-length substrates ; (II) revealing how PRMTs achieve specific arginine methylation on different target sites. The works presented here focused on 3 targets: PRMT2, PRMT3 and PRMT4/ CARM1. We used biochemical, biophysical and structural methods (bio-crystallography and cryo- electron microscopy) to decipher structural clues that drive PRMT-substrate recognition. We developed new chemical probes that can be used in early drug discovery for the conception of PRMT inhibitors
Hossain, Tasnia. « GaN based structures on patterned silicon substrate : stress and strain analysis ». Nice, 2012. http://www.theses.fr/2012NICE4096.
Texte intégralLe présent travail concerne l’étude des contraintes et des déformations dans le matériau GaN épitaxié par EJM et par EPVOM sur substrat silicium texturé en vue d’éviter la fissuration du matériau et ainsi obtenir des motifs compatibles avec la réalisation de composants (DELs, Lasers, transistors etc. ). Nous avons étudié des motifs différents en tailles, séparations, hauteurs de tranchées, formes, orientations dans le plan ainsi que deux orientations cristallines du substrat silicium. Au-delà d’une épaisseur critique du film déposé, pour une forme de motif donnée, la fraction de motifs fissurés augmente avec la taille des motifs. 88% des motifs en losange et 96% des motifs carrés sont exempts de fissures pour des films GaN épais de 12 μm pour une largeur égale à 200 μm. Une distribution en U de la contrainte en tension est mise en évidence par spectroscopie micro-Raman et par micro-photoluminescence pour les différentes tailles de motifs étudiés, le maximum de contrainte se situant en leur centre et la contrainte se relaxant graduellement vers les bords libres. La contrainte augmente avec la taille des motifs, mais diminue avec la hauteur des tranchées réalisées dans le substrat. Un modèle analytique a été adapté pour rendre compte de la répartition des contraintes. La distance séparant les motifs influe peu. Quoi que la répartition des contraintes puisse être différente durant la croissance, nous avons montré la possibilité d’obtenir des films de GaN avec une bonne qualité cristalline sur ces motifs, ce qui montre que cette voie est prometteuse pour la fabrication de composants optoélectronique et électroniques jusqu’ici limités par la croissance sur substrat planaire
Wickham, Shelley. « DNA origami : a substrate for the study of molecular motors ». Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.561126.
Texte intégralVigbedor, Maa Ohui Shormeh. « Structure and regulation of G-substrate in neurodegenerative disease ». Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8292.
Texte intégralBadin, Mihaela Georgeta. « Self-assembled monolayers on gold substrates structure and characterization ». Saarbrücken VDM Verlag Dr. Müller, 2007. http://d-nb.info/988947358/04.
Texte intégralBednarczyk, Dallas Joesph. « The influence of substrate structure on organic cation transport ». Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/290546.
Texte intégralDafforn, Katherine Ann Biological Earth & Environmental Sciences Faculty of Science UNSW. « Anthropogenic modification of estuaries : disturbance and artificial structures influence marine invasions ». Awarded by:University of New South Wales. Biological, Earth & ; Environmental Sciences, 2009. http://handle.unsw.edu.au/1959.4/44778.
Texte intégralArgoud, Maxime. « Mécanismes de collage et de transfert de films monocristallins dans des structures à couches de polymères ». Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00848111.
Texte intégralMichel, Jean-Philippe. « Films smectiques minces déposés sur un substrat monocristallin ». Cergy-Pontoise, 2002. http://www.theses.fr/2002CERG0169.
Texte intégralThis work presents an experimental study of the structure of thin smectic films frustrated on a single crystal. Film thicknesses are investigated from several hundreds to several tens of smectic layers. We worked on the model system 8CB/MoS2 by combining four different experimental techniques, llowing an exploration of the layers structure everywhere in the film. We demonstrate we are able to study sual defects of the smectic phase in a simplified geometry because of the order imposed via the substrate's surface. Combination of Scanning Tunneling Microscopy (STM) and Grazing Incidence X-ray effraction (GIXD) permit to take interest to the physisorption of organic molecules on a crystalline surface and more precisely to determine the fine structure of the first 8CB adsorbed molecules on MoS2 surface. We interpret our results through a1D mean field model leading to a complex molecule-substrate. In a second time, by combining Optical Microscopy (MO) and GIXD we studied the unidirectionnal planar anchoring of the smectic A and nematic phases imposed by the flat surface of MoS2. We have determined six different anchoring directions for the perpendicularly anchored smectic layers with respect to the main crystallographic directions of MoS2. With models existing in the litterature, we have then interpreted our results and evidenced the strong link between the adsorbed structure and the anchoring characteristics. Film's structure frustrated by antagonistic anchorings was investigated by combination of MO, GIXD and Atomic Force Microscopy (AFM) in the Tapping mode. For thickness higher than 0,1 mm, smectic layers are stacked concentrically into periodic networks formed by flattened hemicylindrical structures. We have evidenced the existence of an elastic threshold located between 700 and 900 Å, below which a discontinous structure with dislocation walls exists in order to avoid any prohibitive curvature of smectic layers. We have demonstrated the asymmetric nature of the walls associated to a high dislocation density. Thickness evolution has revealed also the presence of such a discontinous structure under the flattened Hemicylindrical structures and permit to understand the defect evolution when film's thickness varies. We have then studied straightforward the internal structure of focal conics, which here are 1D degenerated
Preuss, Monika Kathrin. « Recognition of secondary structure by the molecular chaperonin groEL ». Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313410.
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