Tesis sobre el tema "Voie Gac"
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Dupont, Charly. "Caractérisatiοn mοléculaire des mécanismes de cοmmunicatiοn aérienne chez la sοuche Ρseudοmοnas fluοrescens ΜFE01". Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMR021.
Texto completoVolatile organic compounds (VOCs), by-products of metabolism emitted by all living organisms, arevolatile under environmental conditions due to their physicochemical properties. In bacteria, especiallythose of the genus Pseudomonas, VOCs are mainly studied for their ability to inhibit phytopathogenicmicroorganisms. Their role in communication, which is a crucial mechanism for coordinating bacterialcommunities during biofilm formation, is understudied.This research focuses on investigating VOCs emitted by the Pseudomonas fluorescens MFE01 strainand their implications in its communication. The uncharacterized communications pathways of MFE01are untypical and does not involve pathways already described in others Pseudomonas.Characterization of molecules the emitted by MFE01 reveals a huge emission of 1-undecene. A mutantlacking the undA gene, responsible for 1-undecene synthesis, no longer emits this VOC and exhibitsreduced biofilm formation capabilities. Exposure of this mutant to exogenous 1-undecene restoresbiofilm formation, Therefore, 1-undecene seems to be an intraspecific communication molecule in P.fluorescens MFE01. The undA gene seems to be in an operon with the rbdA gene, encoding a putativesensor. We hypothesize that Rbda is involved in 1-undecene perception with signal transduction likelyoccurring via the synthesis of cyclic di-guanosine monophosphate, a known secondary messenger thatinduces biofilm formation.Additionally, the study of the Gac/Rsm regulatory pathway, a critical regulator of metabolism andcommunication in Pseudomonas, demonstrates that it strongly modulates the quantity and profile ofVOCs emitted by MFE01. This pathway governs 1-undecene emission and the aerial inhibition of humanpathogen Legionella pneumophila and phytopathogen Phytophtora infestans by MFE01. At least oneVOC, possibly 2-tridecanone and/or 2-undecanone, may activate the expression of the gacS gene,which encodes the principal sensor of the Gac/Rsm pathway
Zaitsev, Andrii. "Exploration de la voie plasma pour la synthèse de nanostructures et de nanocomposites à base de polyaniline". Thesis, Le Mans, 2015. http://www.theses.fr/2015LEMA1014/document.
Texto completoPolymer nanostructures are of great interest due to their unique properties such as high shape factor. This property is essential for applications where surface interactions are involved. One example of such an application is the gas detection. Polyaniline (PANi) has been shown as a promising material for ammonia detection. Conventional synthesis (chemical orelectrochemical) of PANi nanofibers has been widely described in the literature but this way has many drawbacks. They include several steps (synthesis, purification, deposition on the substrate) and the use of chemicals (oxidants, acids) which are not environmentally friendly. The polymerization assisted by cold plasma (PECVD) allows overcoming it, as only themonomer is used and is directly polymerized on the substrate. This thesis work aims to develop plasma polyanilinenanostructures while retaining the monomer unit in the polymer. The key parameter that determines thenanostructuring process is the discharge power. At high power, highly structured films are obtained but the monomer molecules are totally fragmented. On the contrary, low power allows conservation of the monomer unit but no surface structuring is observed. We developed a method which combines the advantages of each regime. This "bottom-up" process consists to vary the input power during deposition in two or three stages. Parameters influencing the chemical and morphological structures are determined and the two and three steps methods are compared. Furthermore, the "top-down" synthesis of nanostructures by etching the PANi layer is also studied according to the plasma parameters (power and discharge time, etching gas flow rate and substrate bias). Finally, in plasma phase, we synthesized nanocomposite by combining PANi nanostructures and sputtered Pd particles. The chemical structure of the PANi films is characterized by UV-Vis spectroscopy, FT-IR and XPS. In order to highlight the nanostructuring of thin films, SEM and AFM microscopy areused. The latter one allows also the calculation of the roughness and specific surface of the PANi. EDX spectroscopyis used to bring out the presence of palladium and to quantify it. Finally, the obtained layers are characterized under gas byabsorbance variation measurements in order to determine their sensitivity and response time to ammonia
Anki, Fatiha. "Etude et analyse de deux dispositifs industriels de traitement d'effluents gazeux acide par voie semi-humide et étude d'un procédé d'élimination du mercure gazeux par adsorption sur charbon actif". Vandoeuvre-les-Nancy, INPL, 1998. http://www.theses.fr/1998INPL057N.
Texto completoBach, Benoît. "Rôle de la voie GAD/GABA chez Saccharomyces cerevisiae en fermentation oenologique". Montpellier 2, 2007. http://www.theses.fr/2007MON20027.
Texto completoThe γ-aminobutyrate (GABA) shunt is an alternative route for the conversion of glutamate into succinate, which involves a glutamate decarboxylase, a GABA amino-transferase and a succinate semi-aldehyde dehydrogenase, encoded in S. Cerevisiae by GAD1, UGA1 and UGA2 respectively. A functional analysis of this pathway showed that glutamate is metabolised through this pathway at a very low rate. On the other hand, exogenous GABA is efficiently converted into succinate via Uga2p and Uga1p, with a yield up to 0,7 mol/mol. A significant part of GABA is accumulated intracellularly, probably in the vacuolar compartment. In addition, we demonstrated the existence in yeast of an alternative pathway for GABA degradation, which involves its reduction in γ-hydroxybutyrate (GHB), this compound being used as a monomer for the formation of polyhydroxybutyrates (PHB). The impact of GABA catabolism on yeast metabolism was then investigated at the metabolic and transcriptomic levels. Genes differentially expressed in the presence of GABA were mostly involved in metabolic functions (GABA pathway, carboxylic acids, nitrogen compounds, sterols). The assimilation of GABA resulted in fluxes redistribution at the pyruvate node, which was well correlated with the transcriptional changes. These modifications, which favour the TCA pathway at the expense of the ethanol/acetate route might reflect the metabolic response of yeast to a higher demand for α-ketoglutarate, used for GABA transamination and to the changes in the availability in redox cofactors due to the dehydrogenase activity of Uga2p. In addition of providing new insights on the role of the GABA pathway in yeast, this work also highlights the role of GABA, which is found in grape must, as a significant source of succinic acid in wine
Delafosse, Eric. "Enjeux gaziers dans les pvd et dépassement des obstacles à l'utilisation de la ressource". Dijon, 1993. http://www.theses.fr/1993DIJOE005.
Texto completoUp to now, the development of natural gas industry has been limited mostly to North America, Europe and Japan. Natural gas in widely appreciated as an energy source due to its abundance, physical characteristics and low production cost. Because of high transportation cost, the future development of the natural gas industry is closely tied the creation and growth of new gas markets in dc's located close to production areas. To date, here has been little gas industry development in these zones due to organisational, structural and economic barriers which driven transaction costs. These problems, however, can be overcome rising industrial organisation economics. The analytical process focuses on firms, industry structures, market configurations and heir interactions. Transaction cost analyses helps us to understand the links between different upstream and downstream processes : namely gas production, gas transportation and electric power generation. The bilateral exchange model and analysis of long term us contracts allow us to develop a new understanding of contract's role. The analysis finally shows how to reduce transaction costs
Blot, Vincent. "Trafic intracellulaire des protéines de structure retrovirales au cours des étapes tardives du cycle replicatif". Paris 7, 2003. http://www.theses.fr/2003PA077203.
Texto completoGuéret, Christophe. "Valorisation du méthane en hydrocarbures supérieurs par voie thermique : étude paramétrique et modèle cinétique". Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL010N.
Texto completoGrossiord, Benoît. "Metabolisme du galactose par la voie de leloir : l'operon gal de lactococcus lactis". Montpellier, ENSA, 1998. http://www.theses.fr/1998ENSA0024.
Texto completoAl-Oufi, Fahd M. "An investigation of gas void fraction and transition conditions for two-phase flow in an annular gap bubble column". Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8499.
Texto completoKay, James. "Gas transport and void evolution in composite prepregs". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/63370.
Texto completoApplied Science, Faculty of
Materials Engineering, Department of
Graduate
Bart, Jean-Michel. "Oxydation sur catalyseur trois voies des differents hydrocarbures et dérivés oxygénés présents dans un gaz d'échappement issu d'un moteur à allumage commandé". Nancy 1, 1992. http://www.theses.fr/1992NAN10389.
Texto completoCOYLE, PATRICK O. "SIGNIFICANT MALE VOICE REPERTORY COMMISSIONED BY AMERICAN GAY MEN'S CHORUSES". University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1151349055.
Texto completoBettler, Emmanuel. "Oligosaccharides et xénotransplantation : étude et production par voie biotechnologique du xénoantigène Gal[alpha]Gal : modélisation de l'[alpha]-galactosyltransférase". Grenoble 1, 2000. http://www.theses.fr/2000GRE10131.
Texto completoBenisty, Henri. "Couches d'accumulation geantes a diverses interfaces silicium/electrolyte solide : effet de champ par voie electrochimique". Paris 6, 1989. http://www.theses.fr/1989PA066042.
Texto completoTaimoor, Aqeel Ahmad. "Valorisation de biogaz pour industrie chimie par voie catalytique". Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00881030.
Texto completoMacquin-Mavier, Isabelle. "Tachykinines, bronchoréactivité et inflammation des voies aériennes". Paris 12, 1994. http://www.theses.fr/1994PA120044.
Texto completoPonticaud-Laurent, Carine. "Etude de la nitruration de l'alliage de titane le Ti-6A1-4V". Limoges, 2002. http://www.theses.fr/2002LIMO0066.
Texto completoThe aim of studying the titanium alloy, Ti-6A1-4V, nitridation is to give more oxidation resistance and a better superficial hardness to this material. In order to understand and better know all the mechanisms, two surfaces treatments have been studied. First, it is the gaseous nitridation and second, to find a quicker treatment realisable at atmospheric pressure, plasma jet nitridation has been studied. In the case of gaseous nitridation, it has been proved that reaction is governed by a single mechanism, whatever the temperature is (between 1175°C and 1300°C), based upon the nitrogen diffusion toward the substrate. This diffusion creates nitrided phases succession going from the( )-TiN stoechiometric nitride to the α-(Ti, N) phase. In the substrate's hearth, α-(Ti,N) and β-(Ti, N) needles appear. For the superficial plasma jet nitridation of the titanium alloy, we have demonstrated that the reaction can occur at atmospheric pressure, thanks to a round injector, put in near the substrate surface (in our case 10 mm). To increase the surface reactivity, a heating cycle can be imposed to the sample. In less than 15 minutes, the surface has a golden and homogeneous colour and the surface's hardness is considerably increased (by ywo)
Mariotte, Bruno. "La mesure nocturne des gaz du sang par voie transcutanée dans la mucoviscidose : une analyse de quinze dossiers cliniques". Montpellier 1, 1992. http://www.theses.fr/1992MON11127.
Texto completoGirard, Vincent. "Etude des propriétés de regénération par voie oxydante d'oxydes métalliques sulfurés". Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-00944308.
Texto completoBocquet, Pascal. "Etude numérique et expérimentale d'un réacteur de dépôt sur fibre par voie PVD". Paris 11, 2001. http://www.theses.fr/2001PA112324.
Texto completoThis thesis is devoted to the study of a triode cathodic tubular sputtering device with a magnetic confinement. This facility, designed by the ONERA, is used for the online production of titanium alloy coat on silicon carbide (SiC) fibres for the industrial manufacture of metal matrix composites (MMC). The work reported in this thesis is based on the study of the argon plasma used in the reactor. It aims at answering the two following questions: how this production tool is working? and what is about its limitations? Concurrently with the experimental studies, we developed and used a particles simulation code (MCC-PIC) of the coating chamber. It gives access to some plasma parameters hardly measurable because of the tubular geometry of the device. The comparison between the coatings produced with static and running fibres, the spectroscopy measurements and the numerical results allow us to understand the major part of the physical phenomena observed in the discharge. .
Aurousseau, Marc. "Étude d'un procédé électrochimique de dépollution d'effluents gazeux contenant du dioxyde de soufre et des oxydes d'azote, par voie directe ou indirecte à l'aide du couple Redox Ce(III)/Ce(IV)". Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL138N.
Texto completoDejan, Jovanov. "Model optimizacije monitoringa deponijskog gasa i procedne vode na zatvorenim deponijama". Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2016. http://www.cris.uns.ac.rs/record.jsf?recordId=101593&source=NDLTD&language=en.
Texto completoThis doctoral dissertation, by using the linear programming, has definedthe various optimization models for the monitoring of landfill gas andleachate at the closed landfills. The development of the model is basedon graphical method of linear programming and the usage of GeoGebrasoftware. According to the results, leachate monitoring parameters andlandfill gas and leachate monitoring volume have been identified. Theeconomical and legislative effects of the models have also beenevaluated, as well as the considerate possibilities for financial savingand improvement of the closed landfill monitoring process.
Gaddari, Abdelhadi. "Nouvelle méthode d'élaboration par voie sol-gel des couches minces de dioxyde d'étain : Applications à la détection à température ambiante d'ozone et d'ammoniac". Phd thesis, Université de Franche-Comté, 2013. http://tel.archives-ouvertes.fr/tel-01020790.
Texto completoAddali, Abdulmajid. "Monitoring Gas Void Fraction In Two-Phase Flow With Acoustic Emission". Thesis, Cranfield University, 2010. http://hdl.handle.net/1826/4475.
Texto completoBenachour, Mohand. "Conception et étude d'un absorbeur à base d'un venturi haute énergie en vue du traitement de gaz acides par voie semi-sèche". Vandoeuvre-les-Nancy, INPL, 1990. http://www.theses.fr/1990INPL086N.
Texto completoKholi, Nizar. "Optimisation et modélisation de dispositifs de traitement d'effluents gazeux acides par voie semi-sèche". Vandoeuvre-les-Nancy, INPL, 1992. http://docnum.univ-lorraine.fr/public/INPL_T_1992_KHOLI_N.pdf.
Texto completoYang, Xiao-Ling. "Étude cinétique d'un procédé de désulfuration de gaz par voie bactérienne en vue de son optimisation : transfert de matière gaz-liquide : biocinétique de la désulfuration". Châtenay-Malabry, Ecole centrale de Paris, 1988. http://www.theses.fr/1988ECAP0080.
Texto completoNoonan, Krist Anthony. "Conceptualising the void : Bridging the gap between semantic cognition and cognitive control". Thesis, University of Manchester, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517858.
Texto completoBrady, Christopher E. "White Students in Urban Schools: The Unheard Voice in the Achievement Gap". Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1364434229.
Texto completoDurand, Véronique. "Développement d’un nouveau procédé de synthèse de membranes inorganiques ou composites par voie CO2 supercritique pour la séparation de gaz". Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20175.
Texto completoUsing membranes for the separation/purification of gas mixtures makes possible the implementation of continuous processes with low energy consumption. Membrane performance being directly related to their synthesis/modification method, a new membrane generation is expected from the original "dynamic" deposition method which has been designed and developed in this work, in supercritical CO2 (scCO2) media. Indeed, the properties of supercritical fluids are intermediate between those of liquids and gases (high density and diffusivity, low viscosity), original membrane microstructures are expected to be derived from this process. The selected precursors are solubilized in compressed CO2 and then transported to the membrane support. This method has been explored for both: i) the synthesis of silica-based membranes on macroporous supports and ii) the modification of MFI zeolite membranes by either alkoxides (MDES, TEOS) or fluorinated oligomers. In the first case, an investigation of the deposition parameters demonstates that the sol-gel chemistry (controlled mainly by temperature) masters the final material microstructure, through the degree of condensation/crosslinking of the deposited clusters. Modification of MFI zeolite membranes with alkoxides can double their initial He/SF6 permselectivity without lowering too much their permeance (Π(He)~10-6 mol.Pa-1.s-1.m-2). In this case, the alkoxide fixation is monitored by the strength, nature and availability of acid sites in the MFI network. MFI membranes modified with fluorinated oligomers are SF6-tight and their He/N2 permselectivity can reach 136 at 25°C (Π(He)~10-8 mol.Pa-1.s-1.m-2). This new dynamic deposition/modification method developed in this work appears as a versatile approach in which the final material structure can be controlled by adjusting the process parameters
Cordell, Laura Michele Portune. "Bridging the Gap, Transitioning Vocalists from Academia to Career". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1311268981.
Texto completoLainée, Pierre. "Effets de l'ypérite (gaz moutarde) sur le système respiratoire après administration par voie aérienne : études in vitro et in vivo". Paris 5, 1993. http://www.theses.fr/1993PA05CD11.
Texto completoFohanno, Stéphane. "Contribution à l'étude des collisions entre particules et des interactions particules-parois en écoulement gaz-solide, par voie expérimentale et simulation lagrangienne". Nancy 1, 1997. http://www.theses.fr/1997NAN10261.
Texto completoThe aim of the present work is to bring experimental and numerical contributions to the knowledge of the effects of collisions between particles in gas-solid flows. A Lagrangian simulation, using a probabiIistic model to take particIe-to-particle collisions into account is used. The first chapter consists in a review of previous works on these collisions and on particle-wall interactions in gas-solid suspension flows. The second chapter explains the development of an original experimental facility allowing the investigation of a gas-solid flow, in a vertical convergent channel, where effects of collisions between particIes are preponderant. Then, the third chapter describes the photographic technique of visualization and the image analysis method. Experimental results (Chapter IV) obtained for two mass flow rates of spherical glass beads (3mm in diameter) show the influence of collisions between particles on the evolution of the characteristics of the flow (velocity and concentration profiles). This experimental work is completed with measurements of particle-wall interactions characteristics (restitution and friction coefficients, roughness parameter) in our experiments. Next, the study of the influence of each parameter used to model particle-wall interactions and particle-to-particle collisions in the Lagrangian simulation is realized in chapter V. Finally, experimental resuIts are compared with predictions of this simulation (Chapter VI). The relevancy of using a probabilistic model to take collisions between particles into account is shown. An improvement of this model has been proposed. Nevertheless, it still needs to be improved. Departure from sphericity of the particles should also be modelled to get better predictions
Nikola, Džolev. "Model energetskog iskorišćenja deponijskog gasa na deponijama sa recirkulacijom koncentrata i procedne vode". Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2018. https://www.cris.uns.ac.rs/record.jsf?recordId=107606&source=NDLTD&language=en.
Texto completoLandfill gas resulting from the anaerobic processes in the waste at the landfillcan be used as a renewable energy source, reducing both airpollution. Treatment of leachate in modern plants for the purification usingreverse osmosis gives unwanted residue - concentrate, which is typicallyrecirculated back to the landfill as a form of its treatment. This thesis dealswith the influence of recirculation in the production of landfill gas, to allow forbetter handling and prediction of entire process of waste management inorder to maintain stable production of landfill gas and increasingopportunities for its utilization in thermal and power plants.
Brini, Ahmed Salem Kalifa. "A study of gas lift on oil/water flow in vertical risers". Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/8507.
Texto completoLetort, Sophie. "Nouvelles voies d'accès à des épurateurs oligosaccharidiques d'agents organophosphorés neurotoxiques - Développement de relations structure-activité". Rouen, 2014. http://www.theses.fr/2014ROUES011.
Texto completoChemical weapons still present a real threat to the civilian and military populations. Previous works in the laboratory were focused on syntheses of β-cyclodextrin derivatives (β-CD) monofunctionalized by an α nucleophile, and on testing of their activity against organophosphorus nerve agents. New derivatives of β-CD heterodifunctionalized by an iodosobenzoic acid group and an imidazole ring were synthesized to reproduce a concerted mechanism like in some enzymatic process. We also developed a prophylactic application of these scavengers by grafting on a textile material to design protective clothings. A protocol for evaluating the rate of accessible sites on the textile was established. The rate of accessible sites (≈ 600 mg/m2) is enough to carry on our investigations into these "smart" textiles. Finally, the OPasic activity of these new textiles against cyclosarin and VX is currently determined by TNO society (Netherlands)
Ruys, Victor. "Rhéologie des résidus agricoles pour un procédé multi-étapes de méthanisation en voie sèche". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI064/document.
Texto completoThe Arkometha® process uses biogas injections to mix agricultural residues (manure, slurry, silage, straw) in a dry anaerobic digestion process. Knowledge of the rheological properties of these materials, rarely studied in the literature, and especially not on an industrial scale, is an essential element to supervise and control the mixing process. This thesis aims to improve the understanding of the physical and rheological evolutions of these materials along the anaerobic digestion process. The literature showed the need for a rheometer able to measure the rheological properties of these products at the industrial scale. For this purpose, specifications were established based on the scientific and technical constraints imposed by these materials, which are considered as fiber concentrated suspensions. On this basis, a large rheometer for substrates, called RGDS for (Rheometer Grand Dimensions for the Substrate), was built, validated and commissioned on an industrial site. The van test technique was used to measure the yield stress and mixer blades, calibrated using the Couette analogy, were used to measure shear stresses. In the third chapter we have shown the utilization limits of the total solids (TS%), traditionally used as the main parameter for rheology controlling. In this chapter we treated the yield stress of these materials as a rheological parameter example. We have shown that it is more appropriate to control the water distribution in order to control the rheological properties of theses suspensions by taking into account the spongy nature of the lignocellulosic material. We have shown how to determine the critical concentrations separating the semi-concentrated, concentrated, triphasic and the wet granular behaviors and their relationship with yield stress. In the fourth chapter, we studied the effect of changes in the anaerobic digestion operating parameters, such as fiber size, temperature and TS on the rheological properties of materials. Several models and empirical equations have been proposed to quantify the advantage of making changes in the operating parameters on the rheology of these materials
Lang, Natacha. "Nouvelles voies d'échange dans les matériaux mésoporeux : application à la séparation azote-oxygène de l'air". Lyon 1, 2003. http://www.theses.fr/2003LYO10169.
Texto completoAl, Kazzaz Marwan. "Pyrolyse du chlorure de méthyle induite par le chlore : une nouvelle voie de valorisation du méthane". Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL024N.
Texto completoSILVA, RAIMUNDO D. da. "Medida de fracao de vazio em escoamento bifasico, gas-agua, em tubos verticais usando absorcao gama". reponame:Repositório Institucional do IPEN, 1985. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9853.
Texto completoMade available in DSpace on 2014-10-09T13:57:55Z (GMT). No. of bitstreams: 1 02297.pdf: 1929315 bytes, checksum: 1f3c8c5cb4048eb63b32ec185d9f1b49 (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
Almabrok, Almabrok Abushanaf. "Gas-Liquid Two-Phase Flow in Up and Down Vertical Pipes". Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/8447.
Texto completoBettignies, Geoffroy de. "Analyse fonctionnelle de la Rho GAP codée par le gène RGD1 chez la levure Saccharomyces cerevisiae : mise en évidence de relations avec la "voie PKC"". Bordeaux 2, 2000. http://www.theses.fr/2000BOR28740.
Texto completoDario, Danojević. "Oplemenjivanje šećerne repe u cilju povećanja tolerantnosti prema abiotičkom stresu - nedostatku vode". Phd thesis, Univerzitet u Novom Sadu, Poljoprivredni fakultet u Novom Sadu, 2014. https://www.cris.uns.ac.rs/record.jsf?recordId=90180&source=NDLTD&language=en.
Texto completoThe most limiting factor for production of all plant species is the lack of appropriate amount of water. Breeding of new genotypes with increased tolerance to the water stress would lead to more stable yields under dry conditions. Breeding for this abiotic factor is time-consuming and requires significant financial resources. There have been very few researches of the impact of water stress in the sugar beet using morphological and physiological parameters in the parent lines and their hybrid combinations. Therefore, the search for simple and rapid methods for the description of breeding materials in relation to water stress, play an important role in breeding programs.The aim of this research was to examine the differences between parental lines and their hybrids under water deficit for 10 selected traits: (fresh root weight, dry rootweight, number of leaves, lamina weight per plant, petiole weight per plant, stomatal density, stomatal diffusive resistance, proline content, relative water content in leaves and specific leaf weight). The aim of this research was also to test combining ability of lines, correlation between the traits and which trait could be used as a reliable parameter in water stress conditions.As plant material were used: 4 monogerm fertile sugar beet inbred lines with different tolerance to leaf wilting in field conditions (lines 3, 4, 5 and 6), 2 monogerm cytoplasmic male sterile testers (lines 1 and 2) and their hybrids 8 (3x1, 3x2 , 4x1, 4x2, 5x1, 5x2, 6x1 and 6x2). Plants were grown in a greenhouse, and there were applied two treatments of irrigations: 30% of the daily water need (DWN), 60% of the DWN and control (100% of DWN).Line 3 and 4 (in the field marked as sensitive to water stress) had a lowest fresh root weight. Root weight as one of the most important trait in breeding was positively correlated with the lamina weight and petiole weigh in the control and in the treatments. Lines 3 and 4 had lowest lamina weight in the control (100% DWN) and 60% of DWN. The higher content of proline and higher specific leaf weight cannot be used as a suitable trait for higher tolerance to water stress. Lines 3 and 4 were separeted by PCA analysis from other genotypes. These lines were marked as sensitive to water stress in field conditions. According to cluster analysis, the root traits were the most correlated with lamina weight, petiole weight, number of leaves and RWC. These traits are significant for sugar beet breeding in well water and dry water conditions. Stomatal density, stomatal diffusive resistance, specific leaf weight and proline content were in the lowest correlation with root traits.
Amon-Mézière, Isabelle. "Étude de l'élimination sur catalyseurs trois-voies à base de palladium des différentes catégories d'hydrocarbures imbrulés présentes dans les gaz d'échappement automobiles". Nancy 1, 1996. http://www.theses.fr/1996NAN10023.
Texto completoBérard, Rémi. "Formation et croissance par voie plasma d'analogues en laboratoire de poussières d'étoiles : exploration du rôle du rapport C/O et des métaux". Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30178.
Texto completoDust formation is a fundamental topic in both cold plasma physics and astrophysics. This PhD thesis, carried out at the interface between these two fields, aims to better understand the formation of stardust. The problem is treated experimentally in cold plasmas and discussed in the context of the environment of evolved stars. We observe the formation of successive generations of dust due to pulsed injection of hexamethyldisiloxane (HMDSO: Si2O(CH3)3) in a capacitively-coupled radiofrequency asymmetric plasma sustained in argon. The used molecular precursor contains potential stardust forming elements, like carbon, oxygen, silicon and hydrogen. Our approach involves different steps: study of the dust formation in the plasma, dust collection, characterization of the dust properties and correlation of the plasma parameters with the dust characteristics. We have thus succeeded to identify optimum conditions for the formation of organosilicon dust with typical size of 50 nm. A major factor impacting dust formation in evolved stars is the variation of the C/O ratio, which is though to determine two large families of stardust, silicates (C/O < 1) and carbonaceous dust (C/O > 1). To explore this effect, we have enriched the Ar/HMDSO mixture with oxygen aiming at a variation of the C/O ratio in the plasma. Above a certain quantity of oxygen, dust is not formed anymore in the plasma. The abundance of oxygen limits dust formation through inhibition of the dust seeds in the gas phase. Instead, deposition of a silica-like matrix is favored. The role of metals is studied through sputtering of a silver target during organosilicon dust formation. We have demonstrated the formation of dust with composite structure in this case. Dust contains crystalline silver nanoparticles that attach to the amorphous organosilicon dust during their growth phase. Moreover, the presence of silver leads to a large variety of molecules composed of species containing Ag and/or Si and hydrocarbon species. Those molecules reveal a complex chemistry around three competitive processes at molecular scale: dust formation involving molecules such as SiCH3 or SiOCH3, metallic grains with clusters of Agn and aromatic molecules of large size such as C16H10 and C24H12, whose formation path involves radicals and possibly an organometallic chemistry as revealed by AgC5H6 and AgC13H8. The above results demonstrate the undoubted necessity to tackle stardust formation by taking into account the chemical complexity of these media
Vidal, Michel. "Exploration à l'échelle moléculaire des domaines SH3 des protéines GAP et GRB2 dans les voies de transmission du signal mitogène". Paris 5, 1997. http://www.theses.fr/1997PA05P620.
Texto completoColomer, Claude. "Plasticité des voies de communications intercellulaires dans la glande médullosurrénale en réponse au stress". Montpellier 2, 2008. http://www.theses.fr/2008MON20177.
Texto completoAn increase in circulating catecholamine levels is one of the mechanisms whereby organisms cope with stress. In the periphery, catecholamines mainly originate from the sympathoadrenal system. The secretion of catecholamines by adrenal chromaffin cells is a key event in response to stressors and it is chiefly controlled by trans-synaptically released acetylcholine from the splanchnic nerve endings. As supported by earlier results obtained in the laboratory, in addition to the central control through cholinergic innervation, a local gap junction-delineated route mediating intercellular electrical coupling between chromaffin cells is involved in the hormonal secretory process and represents an efficient complement to synaptic transmission able to amplify catecholamine release after synaptic stimulation. Whether these two communication pathways (i. E. Synaptic neurotransmission and gap junctional coupling) contribute to stress-evoked increased catecholamine secretion still remains unknown. We addressed this issue using acute adrenal slices from stressed rats (5 day-cold exposure). Our results show that in cold exposed rats, gap junctional communication undergoes a functional plasticity, as evidenced by an increased number of dye-coupled cells. Of a physiological interest is that this up-regulation results in the appearance of a robust electrical coupling between chromaffin cells that allows the transmission of action potentials between coupled cells. This enhancement of gap junctional communication parallels an increase in expression levels of connexin36 and connexin43 proteins. Both transcriptional and post-translational mechanisms are involved since Cx36 transcripts are increased in stressed rats and the expression of the scaffolding protein Zonula Occludens-1, known to interact with both Cx36 and Cx43, is also up-regulated. Consistent with an up-regulated coupling in stressed rats, the cytosolic Ca2+ concentration ([Ca2+]i) rise triggered in a single cell by an iontophoretic application of nicotine occurs simultaneously in several neighboring cells. We also showed that in response to stress, both chromaffin cell excitability and chemical transmission at the splanchnic nerve terminal-chromaffin cell synapses are increased. We next investigated whether vasopressin (VP), a neuropeptide known to play a key role in stress response, could be involved in increased gap junctional communication in stressed rats. Our results show that VP and d[Leu4,Lys8]VP, a V1b receptor specific agonist, increase the occurrence of gap junction-mediated synchronized [Ca2+]i transients between chromaffin cells, both in stressed and unstressed rats. This suggests that, although VP can up-regulate gap junctional coupling, it is unlikely the main factor involved in increased gap junctional communication observed in response to stress. Exposure to cold also enhances the synaptic neurotransmission between splanchnic nerve endings and chromaffin cells, as evidenced by an increase in spontaneous excitatory post-synaptic currents (sEPSCs). This correlates with an increased density of nerve fibers innervating the medulla. To go further, we examined whether the nAChR subtype formed by the combination of alpha9 and alpha10 subunits recently identified in isolated rat chromaffin cells is involved in this effect. By using a toxin (alpha-RgIa) to specifically block alpha9/alpha10 nAChRs, we showed that alpha9 /alpha10 nAChRs contribute to synaptic transmission. Interestingly, the expression level of alpha9 receptors is up-regulated in cold exposed rats. In addition, we show that in stressed rats, alpha9 /alpha10 nAChRs mainly contribute to acetylcholine-induced currents, as compared to alpha3 nAChRs that is the main nicotinic receptor activated in response to acetylcholine in control rats. This indicates that stress also induces nAChR plasticity, at least by acting on the expression level. In sum, the functional changes occurring both on gap junctional communication and on synaptic transmission converge to improve the stimulus-secretion coupling efficiency in the adrenal gland and may represent endogenous mechanisms by which the adrenal medullary tissue ensures appropriate increased catecholamine secretion in response to stressors
Cardwell, Robert Ewell. "A Survey of 21st Century Gay-Themed American Art Songs for Baritone". Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1703289/.
Texto completoPonaire, Sarah. "Synthèse d'analogues de substrats ou d'inhibiteurs d'enzymes de la voie du 2-C-méthyl-D-érythritol 4-phosphate (MEP) pour la synthèse des isoprénoïdes". Strasbourg, 2010. https://publication-theses.unistra.fr/public/theses_doctorat/2010/PONAIRE_Sarah_2010_ED222.pdf.
Texto completoIsoprenoïds are components of the vast family of « natural compounds » present in all living organisms. They are biosynthetically obtained by two distinct pathways: the mevalonate pathway and the 2-C-methylerithritol 4-phosphate pathway; the latter is present in numerous pathogenous microorganisms and parasites. Growing microorganism resistance to antibiotics and antiparasitics forces us to identify new therapeutic targets to fight against pathogens. The great advantage of the 2-C-methylerithritol 4-phosphate pathway is that it is absent in humans thus being the ideal target to discover new antibiotics. To that end, we decided to synthesize six prodrugs derived from two phosphonic acids previously obtained in our research group. The latter, directly related to fosmidomycin were proven to be potent inhibitors of E. Coli’s DXR enzyme. The new prodrugs were tested on tobacco cell cultures, on BY-2 as well on Mycobacterium smegmatis. Results obtained on BY-2 show that our prodrugs are stronger inhibitors than fosmidomycin. Moreover, they still have an inhibitory effect on very low concentrations were fosmidomycin does not. In addition, organic synthesis of 2-C-methylerithritol 4-phosphate was studied. Though various protecting groups of the phosphate moiety were used and numerous protection / deprotection steps were tested, 2-C-methylerithritol 4-phosphate was never obtained. We then pursued our efforts on synthesizing dihydroyacetone phosphate, a small organic compound found in various metabolic pathways. The organic synthesis we propose surpasses all others by its simplicity and efficiency. Finally, we tried to synthesize L-glyceraldehyde 3-phosphate; this compound is the enantiomericaly pure substrate of DXS (deoxyxylulose phosphate synthase). Though many different synthetic schemes were tested, none of them yielded the desired product
Lam, Van Trien. "Les enjeux juridiques de l'intégration des pays en développement dans le régime climatique de "l'après Kyoto"". Rouen, 2013. http://www.theses.fr/2013ROUED012.
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