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Khaldi, Marwa. "Étude du lien entre la physico-chimie de dérivés laitiers et leur aptitude à l’encrassement lors du traitement thermomécanique en échangeur de chaleur". Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10032/document.
This Ph.D. work is a contribution for understanding the fouling in plate heat exchangers (PHE) during the heat treatment of whey protein solutions. This work aims at establishing the relationship between the composition of the different whey protein solutions (β-lactoglobulin content (β-lg) and calcium), their denaturation behaviour and their ability to foul the hot surfaces of the PHE.This study showed the strong impact of the calcium content and the calcium/protein molar ratio on the β-lg thermal denaturation mechanisms, the distributions of the deposit fouling, deposit formation dynamics and the structure of the first deposit layers.The determination of the β-lg denaturation kinetic constants and the knowledge of the thermal profile allowed to simulate the concentration profiles of the different β-lg species (native, unfolded and aggregated) along the PHE and to study the correlation between the dry deposit mass of and the amount of denatured β-lg in the PHE. This simulation highlighted the negligible role of the aggregates in the fouling mechanisms and both the influence of the unfolded species and the calcium content on the distribution of protein deposition. Finally, a new correlation between the distribution of dry deposit masses in each channel of the PHE and the denaturation kinetic parameters was determined for each studied protein solution, showing thus that chemical reaction engineering approaches are requested for predicting proteinaceous fouling
Liu, Weiji. "Rôle de la micelle de caséine sur la dénaturation thermique des solutions de protéines de lactosérum et les mécanismes d'encrassement". Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILR014.
The present work is a contribution to better understand the influence of casein micelles on the fouling of serum whey protein solutions. In particular, experimental and numerical approaches have been carried out, at laboratory and pilot scales, to describe denaturation phenomena and better understand the role of calcium in fouling mechanisms. First of all, the effect of casein/whey mass ratio on the whey protein fouling performance was investigated in a pilot-scale PHE. The total fouling deposit mass drop significantly with the addition of casein, resulting in a minimum value located at Casein/WPI of 0.2. Exceeding this critical ratio, fouling deposit increased with elevated casein concentrations. The deposit mass drop (Casein/WPI ≤ 0.2) is unlikely to be linked to the thermal denaturation of BLG and is more probably due to the change in mineral interactions introduced by casein. The increased fouling mass (Casein/WPI ≥ 0.2) was attributed to a co-precipitation of BLG-casein complex that enhances the fouling. It is proposed that micellar casein change deeply the calcium balance and the content of CaP nanocluster modifies sharply the interactions which occur between protein species (BLG, caseins) and mineral elements (ionic calcium, Ca-P) thereby affecting the protein denaturation and fouling behavior. A novel kinetic model concerning thermal unfolding and aggregation of BLG was established. This model interprets mathematically the break-slope behavior in the Arrhenius plot and provides detailed thermodynamic information for both unfolding and aggregation processes. Based on this model, it was confirmed that ionic calcium has a protective role on the thermal unfolding of BLG at low temperature. In contrast, at higher temperatures, calcium promotes aggregation and the formation of unfolded BLG species. A bench-scale fouling rig was built to perform whey protein fouling experiments in a laminar regime. A realistic 3D CFD model was achieved to simulate both the bulk and surface reactions. Results showed a linear relationship between the deposition pre-exponential factor and calcium concentration, suggesting the fouling is built in such a pattern that only one calcium ion per BLG molecule is involved. Calcium was confirmed to be essential to fouling growth with significant effects both on the thermal denaturation and deposition processes. Finally, the effect of casein/whey ratio on the whey protein fouling was investigated in the laboratory-scale fouling device. Results revealed a similar effect of casein on fouling mitigation as those found in the pilot plant. However, in this case, the fouling was suppressed and maintained at a low extent even at high Casein/WPI ratios (up to 4). The presence of individual caseins in the serum phase was considered to be responsible for this fouling mitigation probably through their chaperon-like activities. However, when the pH of the fouling solution is set at 6.6, casein is shown to lose its fouling-mitigating effect at higher ratios. This behavior is related to its weak ability of casein micelle to control ionic calcium in the serum phase at lower pH, resulting in higher calcium concentration facilitating BLG denaturation and deposition accumulation. A lower amount of dissociated caseins in the serum phase at pH 6.6 could also explain the increase in fouling mass because they are not in sufficient concentration to perform chaperone-like functions
Leroy, Pierre. "Calcium et corrosion". Paris 5, 1991. http://www.theses.fr/1991PA05P623.
Debroise, Théau. "Calcium Oxalate and Calcium Phosphate Biominerals : Formation and Stability studied by Molecular Dynamics". Electronic Thesis or Diss., Sorbonne université, 2019. https://theses.hal.science/tel-04059925.
This thesis is about biomineralisation, the process by which living beings manage to direct the precipitation of minerals present in their environment to make materials useful for the survival of the species in question. Biomineralization is an extremely complex phenomenon involving genetic regulation and the involvement of proteins to trigger mineralization at specific locations. It happens however that it escapes the control of the living organism, then leading to various pathologies. This is the case, for example, when calcifications called kidney stones are formed inside the kidneys. From a certain size, a renal calculus becomes pathological and requires hospital care. The pathology is commonly called urolithiasis. It is established that calcium oxalates, and more particularly the monohydrate (Calcium Oxalate Monohydrate, COM or whewellite) and dihydrate (Calcium Oxalate Dihydrate, COD or Weddellite) phases, make up the majority of kidney stones. The environment, and especially food, is a key factor influencing the formation and composition of kidney stones. Currently, the treatments consist mainly of an injection of analgesics and the ejection of the calculation by the natural channels. If necessary, surgery is performed. Doctors are looking for drugs / treatments that can potentially prevent the formation of kidney stones
Calco, Michel. "Contribution à la valorisation des lactosérums industriels à l'aide des techniques de séparation par membranes". Nancy 1, 1997. http://docnum.univ-lorraine.fr/public/SCD_T_1997_0287_CALCO.pdf.
Chardonnet, Catherine. "Le calcium de la baie de raisin : relation entre la cohésion des parois cellulaires et la sensibilité à botrytis cinerea". Bordeaux 2, 1994. http://www.theses.fr/1994BOR22000.
Jaillard, Benoît. "Les structures rhizomorphes calcaires : modèle de réorganisation des minéraux du sol par les racines". Montpellier 2, 1987. http://www.theses.fr/1987MON20174.
Steger, Laurent. "Etude de l'accélération des ciments à haute teneur en laitier de haut-fourneaux par du chlorure de calcium". Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30333.
Blast furnace slags are a co-product of the metallurgical industry, used in composite cements (CEM II & III) as a partial substitution for Portland clinker and recognized in particular for their advantages in terms of lowering the heat of hydration, increased durability performance and reduced carbon footprint of concrete. Although achieving ultimate mechanical performance comparable to or better than Portland cement (CEM I), binders offering high levels of slag see the development of their mechanical strength greatly slowed down. This phenomenon is explained by a lower reactivity of the slag which requires "activation" conditions to react properly. There are various additives that accelerate the hardening of cements, among which calcium chloride shows the best performance. The effects of calcium chloride are particularly important during the first days of hydration. However, their use is strongly regulated because of the corrosive effect of chlorine on steels of reinforced concrete. The objectives of the thesis are to study the mechanisms of action of calcium chloride on cement-slag binders during the first days of hydration. A panel of experimental techniques has been used to specifically identify the action of chlorides on slag and cement. Coupled results from XRD-NMR SEM experiments show that calcium chloride causes an accelerated precipitation of portlandite and ettringite, resulting from the increase in the reaction rate of clinker. The start of the slag reaction takes place after about 12 hours, and is not impacted by the calcium chloride. On the other hand, the reaction rate of the slag increases in the presence of the accelerator. The rapid, significant and exclusive formation of Friedel salts in the presence of chloride is observed, replacing sulphated and / or carbonated AFm. Increasing the reaction rate of the anhydrous phases results in the precipitation of additional C-S-H. This formation of Friedel salts and C-S-H causes a faster filling of the porosity and the increase of the mechanical performances
Alfaro, Elena. "L'importance des mouvements calciques intra-cellulaires dans la physiologie de l'interaction plaquettes-composés synthétiques". Lyon 1, 1991. http://www.theses.fr/1991LYO1T068.
Etter, Stéphanie. "Etude de la corrosion sous contrainte de certains verres d'aluminophosphates de calcium : effet de la teneur en alumine". Montpellier 2, 2007. http://www.theses.fr/2007MON20234.
Humez, Sandrine. "Mise en évidence et caractérisation d'une conductance proton et son rôle dans la sensibilisation de la libération de calcium par le réticulum endoplasmique dans l'ovocyte de rana esculenta". Lille 1, 1995. http://www.theses.fr/1995LIL10192.
Lecourieux, David. "Analyse fonctionnelle des variations de la concentration en calcium libre dans le cytoplasme et le noyau des cellules de tabac en réponse à des éliciteurs des réactions de défense : identification de protéines kinases cibles". Dijon, 2001. http://www.theses.fr/2001DIJOS062.
Lagoueyte, Nathalie. "Microstructure et rhéologie des coagulums de type présure : actions de la température et de la température et de l'addition de phosphate de calcium". Montpellier 2, 1994. http://www.theses.fr/1994MON20112.
Kedziora, Charlotte. "Propriétés d’usage et mécanismes d’hydratation du système ternaire [Ciment Alumineux – Sulfate de Calcium – Laitier de Haut Fourneau] à haute teneur en sulfate de calcium : De l’approche expérimentale à la modélisation". Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0047/document.
The potential of activation of a Ground Granulated Blast Furnace Slag has been evaluated into a ternary system comprising of a Calcium Sulfate as major component and a Calcium Aluminate Cement. This system is not well known and the main goal of this study is to determine its main advantages and limitations. From the usage properties point of view, fast setting and initial strengths are governed by the ettringitic binder. Then, and only if the dehydration is avoided, slag reacts. In this case, slag contributes to the increase of mechanical performances at medium and long terms and to limit the expansion under water. From an understanding point of view, the original experimental approach reveals the potential of the slag. It is based on a comparison of performances with different types of curing methods. The potential of hydration of the slag is amplified when the system is dehydrated during a few days and then rehydrated. However, slag contribution is complex to establish because analytical methods to follow-up slag consumption (such as X-ray Diffraction and Differential Scanning Calorimetry analysis) are not well adapted. So, to understand the hydration mechanisms, indirect approaches are used. Semi-quantitative methods by X-ray Diffraction to follow-up the mayenite, calcium sulfate, syngenite and ettringite, ThermoGravimetric Analysis to measure degree of hydration and Mercury Intrusion Porosimetry to identify microstructural changes have been carried. The most important difficulty concerns the identification and quantification of amorphous phases such as slag, C-S-H and AH3. That is why a modelling approach is necessary to understand the role of each compound in the ternary mixture and in particular the obvious contribution of slag during rehydration test. This modelling approach increases knowledge of the physical and chemical phenomena in this ternary binder. It is useful to explain the observed macroscopic properties such as strength and helps to determine the kinetics of hydration in porous environment. Even if this model is still under development, it has allowed identifying the sequences of hydration (ettringitic binder reacts at very initial time, then anhydrite transforms into gypsum and slag reacts at long term) and confirms therefore that the reaction of slag is slow
Nisar, Samia. "Role of ATP2B4 and human malaria : looking for functional genetic variants associated with malaria". Thesis, Aix-Marseille, 2020. http://theses.univ-amu.fr.lama.univ-amu.fr/200911_NISAR_992dobfs271wcdsgy656twqjfn399ockic_TH.pdf.
Genome-wide association studies (GWAS) for severe malaria have identified 30 genetic variants mostly located in non-coding regions, with only few associations replicated in independent populations. In this study, we aimed at identifying potential causal genetic variants located in these loci and demonstrate their functional activity. We systematically investigated the regulatory effect of the SNPs in linkage disequilibrium with the tagSNPs associated with severe malaria in several populations. Annotating and prioritizing genetic variants led to the identification of a regulatory region containing 5 ATP2B4 SNPs in linkage disequilibrium with the tagSNP rs10900585. We confirmed the association of rs10900585 and also found significant associations of severe malaria with our candidate SNPs (rs11240734, rs1541252, rs1541253, rs1541254, and rs1541255) in a Senegalese population. Then, we showed that this region had both a promoter and an enhancer activity and that both individual SNPs and the combination of SNPs had an effect using luciferase reporter assays. In addition, CRISPR/Cas9-mediated deletion of this region decreased ATP2B4 transcript and protein levels and increased Ca2+ intracellular concentration in K562 cell line. Taken together, our data show that severe malaria associated genetic variants alters the activity of a promoter with enhancer function. We showed that this enhancer controls the expression of ATP2B4 that encodes plasma membrane calcium-transporting ATPase 4 (PMCA4), which is the major calcium pump on red blood cells. Altering the activity of this Epromoter affects the risk of severe malaria probably through calcium concentration effect on parasitaemia
Julien, Marion. "Phosphate et différenciation des cellules squelettiques". Nantes, 2007. http://www.theses.fr/2007NANT12VS.
This study was divided into two parts. The objectives of the main part were to better understand the role of inorganic phosphate (Pi) in the differentiation of cells responsible for endochondral and membranous ossification, respectively the growth plate chondrocytes and the osteoblasts. The regulation of these ossification processes is related to phosphate metabolism. Deregulation of the phosphatemia can lead to rickets or vascular calcification respectively associated with hypo- or hyperphosphatemia. The role of inorganic phosphate (Pi) in chondrocyte and osteoblast differentiation remains largely unexplored. Using in vitro and ex vivo models (cell lines and primary cultures) we showed in a first part that Pi stimulates the matrix Gla protein (MGP) expression via ERK1/2 in skeletal cells. In addition, we showed that the Fra-1 transcription factor is involved in the intracellular mechanisms involved in the Pi-stimulated MGP expression in osteoblasts. Considering the role of MGP in the control of normal and ectopic mineralization, these data contribute to a better knowledge of the role of Pi in bone formation and homeostasis, which are disturbed in the case of phosphatemia deregulation. In the second part, we contributed to the characterization of two calcium phosphate biomaterials, a bioceramic and an ionic cement. Through these studies we explored two paths of research allowing a modulation of the mechanical and biological properties of calcium phosphate biomaterials. This work provided new insights in the management of calcium phosphate biomaterials (improvement of mechanical properties and bioactivity) as well as the design of innovative bone substitutes
Leba, Louis-Jérôme. "Contribution de CML9, une "Calmodulin-like protein" à la mise en place de réactions de défense chez Arabidopsis thaliana". Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1626/.
In plants, the calcium is considered as an important secondary messenger that can integrate the fluctuations in the environment at the cellular level. Different calcium sensors, such as the calmoduline (CaM), allow to decode this message in cellular and physiological responses. If this family of CaM proteins is present in all Eucaryotes, the plants also possess a family of CaM-related proteins, the CMLs for Calmodulin-like proteins, which appear unique to the plant kingdom. At the moment, only few data are available on this family of proteins. The objective of this thesis concerned CML9, a Arabidopsis thaliana CML. The CML9 gene expression is modulated by diverse stresses. Our analyses revealed that this gene is finely regulated in response to phytopathogenic bacteria through signaling pathways involving the PAMPs and hormonal compounds. So we showed the importance of the salicylic acid and the flagellin in this control. The functional analysis performed by a strategy of loss and gain of function (KO-mutant and overexpressors of CML9) allowed us to show that CML9 plays a regulatory role in the defense of plants against virulent bacteria such as P. Syringae DC3000. Our works also specify that these cml9 genotypes present altered responses to the exogenous application of flg22, the active peptide of the flagellin. All the data obtained leads to think that CML9 might contribute through its interactions with target proteins to modulate some defense reactions in Arabidopsis thaliana
Ridolfi, Michèle. "Fonctionnement stomatique d'arbres forestiers en situation de carence calcique, et dans le cas d'une insensibilité à l'acide abscissique : conséquences pour l'assimilation de carbone". Nancy 1, 1995. http://www.theses.fr/1995NAN10420.
POINDESSOUS, GILLES. "Etude de la germination-croissance du carbonate de calcium par voie electrochimique. Influence de la teneur en oxygene et du transport de matiere". Paris 6, 1998. http://www.theses.fr/1998PA066293.
De, Coninck Arnaud Sidney. "Phytoextraction induite et fractionnement du cuivre dans un résidu minier riche en cuivre et en calcium amendé par un compost". Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25533/25533.pdf.
Bournazel, Marion. "Effet des coproduits riches en fibres alimentaires sur l'utilisation disgestive et métabolique des minéraux chez le porc et le poulet". Thesis, Tours, 2017. http://www.theses.fr/2017TOUR4047.
The optimisation of the use of phosphorus remains a major challenge to ensure the sustainability of poultry and pig industry. Today, the use of co-product, relatively rich in dietary fibre, is increasing. However, dietary fibre is known to modulate digestion processes and digestibility of nutrients. This work contributed to progress on the digestive mechanisms generated by the intake of dietary fibre from coproducts and their effects on the digestion of minerals, in relation with microbial phytase, specifically in pigs and chickens. Their metabolic consequences in terms of mineral and acid-base balance have also been demonstrated. The knowledge gained will contribute to the improvement of the intake of minerals, in particular phosphorus and calcium, in diversified formulas in pigs and the chicken. Finally, this will allow us to better adapt our feeding systems to the challenges of sustainability
Dissaux, Aurore. "Etude et valorisation des principes actifs de biominéralisation du calcium pour les applications pharmaceutiques". Phd thesis, Université d'Orléans, 2010. http://tel.archives-ouvertes.fr/tel-00665124.
Leroy, César. "Oxalates de calcium et hydroxyapatite : des matériaux synthétiques et naturels étudiés par techniques RMN et DNP". Electronic Thesis or Diss., Paris 6, 2016. http://www.theses.fr/2016PA066256.
In France, about 9.8% of the population suffer from urolithiasis. The treatment of kidney stones, composed of 72% of hydrated calcium oxalates (CaC2O4∙nH2O) with n = 1, 2, 3, represents almost 900 million euros in annual spending and it is therefore necessary to understand the in vivo formation of these stones. Here we propose a new approach in order to characterize kidney stones and have a greater understanding of their formation. Physicians primarily use FTIR techniques to determine the major phases present in a given pathological calcification. NMR methods appears suitable to determine more accurately the composition of these pathological calcifications. Very few NMR analyzes of kidney stones and synthetic analogues were conducted to date. In a first step, the three phases of calcium oxalate were synthesized by implementing original protocols. Analysis of the 1H, 13C CP MAS and MAS 43Ca ultra-high magnetic field spectra at natural abundance allow precise identification of the different phases and can be interpreted by taking into account the number of inequivalent crystallographic sites. The hydroxyapatite was studied in parallel as it may also appear in urolithiase. Finally, we show results obtained from DNP MAS at 100 K on the synthetic samples. The affinity of the biradical/solvent combination remains a limiting factor for heterogeneous materials such as those analyzed in this study. We have to be able to find a suitable combination for complex multi-component materials and to obtain an equivalent gain on all signals. In a last step, it is demonstrated that it is possible to transpose the methodological approach presented above to the study of kidney stones
Bach, Quoc Tien. "Influence du remplacement du ciment par des cendres volantes à faible teneur en calcium sur la cinétique de prise de pâtes de ciment au jeune âge". Nantes, 2015. http://archive.bu.univ-nantes.fr/pollux/show.action?id=28eb329d-8730-4b1d-b074-94eb36f39570.
This work deals with the influence of the replacement of CEM I type cement by low calcium fly ash on the hydration kinetics of cement pastes at early-age. Different cement paste compositions are tested. They are characterized by different replacement rates (0%, 40% and 80%) and different water to binder ratios (0. 25 and 0. 50). The study of hydration is based on the experimental measurement of the released heat of hydration (isothermal microcalorimetry), of the amount of portlandite and chemically bounded water (thermogravimetric analysis) and of the evolution of the mechanical properties during the hydration (compressive strength Rc and tensile strength Rt). The results are then used to determine the parameters of the models describing the composed cement paste evolution (Lacarriere 2007) , (Meinhard & Lackner 2008) et (Baert et al. 2010). The second part is dedicated to the study of heat and moisture transfers in the cement paste at early-age. The numerical simulations are carried out to determine the influence of the aggregate thermophysical properties, concentration and shape on the hydration kinetics. These parameters, either physical, composition related ot morphological may have an influence on the medium temperature evolution and consequently on its chemical evolution since the hydration reactions are thermoactivated. The numerical implementation is based on the model by (Di Luzio & Cusatis 2009) discretized by means of the finite difference method (bidimensionnal problem)
Rakotozandriny, Karol. "Investigation of Calcium Oxalate Crystallization under Microfluidic Conditions for the Understanding of Urolithiasis". Electronic Thesis or Diss., Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2019SORUS347.pdf.
Over the past decades, the increase in kidney stone formers has raised the importance to understand the biomineralization process responsible for urolithiasis. Calcium oxalate (CaOx) crystallization – kidney stone main inorganic compound – has largely been characterized under batch synthesis conditions that cannot be regarded as biomimetic with respect to the microscale environment in the kidney and to the urinary flow. In this work, we used a reversible microchannel to mimic the collecting duct in the nephron where CaOx stones can form due to supersaturated levels in calcium and oxalate ions. Within the channel, CaOx crystallization was induced under co-laminar mixing of Ca2+(aq) and Ox2-(aq) ions matching pathological concentrations – i.e. hypercalciuria and moderate hyperoxaluria. Scanning electron microscopy and Raman spectroscopy were used to support our investigations. They showed that CaOx crystals precipitate in a mixture of monohydrated whewellite (CaC2O4.H2O, COM) and dihydrated weddellite (CaC2O4.2H2O, COD) in the microchannel, similar to what is observed by the physicians. In situ information on the kinetics of CaOx crystal growth could be acquired in our microfluidic system. They confirmed the effect of the hydrodynamic and chemical conditions on the growth kinetics and the final chemistry (phase, shape) of the formed CaOx crystals. In a trial to achieve a more complex biomimetic model (formation of kidney stones on a Randall’s plaque), hydroxyapatite was grown also in the microchannel and the CaOx crystal formation was investigated
Bakker, Mark. "Effet des amendements calciques sur les racines fines de chêne (Quercus petraea et robur) : conséquences des changements dans la rhizosphère". Nancy 1, 1998. http://docnum.univ-lorraine.fr/public/SCD_T_1998_0276_BAKKER.pdf.
Court, Mélanie. "Étude des cycles du Ca et Mg dans cinq hêtraies du nord de la France et des modifications induites par un amendement calco-magnésien : utilisation combinée des approches élémentaires et isotopiques (δ26/24Mg, δ44/40Ca et 87Sr/86Sr)". Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0248/document.
In France, many forest ecosystems grow on acidic and nutrient poor soils. In numerous cases, the chemical fertility of forest soils is slowly degrading due to increasing external pressures (e.g. decreasing atmospheric inputs, increasing biomass exportations) and is a growing concern in the international forest community. Forest management often must resort to restauration/remediation practices to ensure the sustainability of the ecosystem. Forest liming with a carbonate product is a known practice to reduce soil acidity, globally improve the ecosystem functioning and compensate nutrient losses caused by biomass harvest and exportation. However, our understanding of the effects of liming on magnesium and calcium biogeochemical processes and cycling in forest ecosystems is still incomplete. This study focuses on the fate of magnesium and calcium originating from the dissolution of liming products in the soils and trees of five beech forests located in Northern France over a period up to 45 years. In order to do so, “conventional” total-element approaches were combined with a multi-isotopic approach (26/24Mg, 44/40Ca et 87/86Sr). At all five sites, the data measured in control plots throughout the study period suggest that the exchangeable pools of nutrient cations in the soil has decreased over the last several decades and that this trend, together with the low chemical fertility level of the soil, was reflected in foliar nutrition (Ca, Mg, K, P). Compared to the control plots, soil exchangeable pools of Mg and Ca in the 0-40cm layer in the limed plots increased during the first decade after liming but differences were no longer observable in soil pools after 20 to 30 years. However, the effect of liming on tree nutrition was still observed after 40 years, most probably because the biological cycling of these elements was enhanced by the lime input. The ecosystem response to the lime input varied between sites depending on the nature of the liming product (CaCO3 or Ca-MgCO3) and the initial chemical fertility level of the soil, the poorest sites showing the strongest responses. The natural variations of Mg, Ca and Sr isotopic ratios combined with conventional approaches highlight the importance of the BIO component of the biogeochemical cycling of Mg and Ca in the studied low chemical fertility beech forests. These isotopic tools also enabled to show the long-lasting incorporation of the Mg and Ca released from the liming product in the biological cycle and highlight the changes in the biogeochemical functioning of these forest ecosystems after the liming operation
Daverat, Françoise. "Tactiques d'utilisation des habitats et dynamique de population des anguilles de la zone aval du bassin versant Gironde Garonne Dordogne : apport de l'étude des otolithes". Bordeaux 1, 2005. http://www.theses.fr/2005BOR13056.
Cheval, Cécilia. "Contribution d'une "Calmodulin-like protein" CML9, et d'un facteur de transcription de type GARP PRR2, à la mise en place des réactions de défense chez arabidopsis thaliana". Toulouse 3, 2013. http://thesesups.ups-tlse.fr/2271/.
Calcium signals are one of the primary mediators of plant defence responses against pathogens. Although rises in cytosolic calcium levels are well described during the plant-pathogen interactions, how calcium signals are sensed and relayed into downstream events is poorly understood. Studies on calcium sensors such as calmodulin and calmodulin-like (CML) proteins have demonstrated a critical role of these calcium signalling components in plants. In this work, evidences were provided indicating that the calmodulin-like protein CML9 is involved in plant immunity in Arabidopsis. CML9 expression is up-regulated during infection with the virulent pathogen Pseudomonas Syringae pv. Tomato DC3000 (Pst DC3000). Recently, using cml9 knock-out mutants and CML9 overexpressors lines, we have demonstrated that CML9 contributes to plant defence mechanisms against Pst DC3000. Search for CML9 interacting partners was performed and among the CML9 binding proteins, a putative GARP transcription factor PRR2 was identified. Then, in my work, a genetic analysis was carried-out and shows that PRR2 is a positive regulator of defence responses when challenged with Pst DC3000. The combination of transcriptomic and phenotyping analyses have demonstrated that PRR2 contributes to plant immunity through a salicylic acid signalling pathway. Moreover, our analyses indicate that PRR2 is a positive regulator of camalexin and callose production in response to Pst DC3000. These findings contribute to decipher a novel calcium signalling pathway mediated by a plant specific calcium sensor and a potential transcription factor during biotic stress
Xiong, Tou Cheu. "Le noyau de la cellule végétale est-il autonome en matière de signalisation calcique?" Toulouse 3, 2005. http://www.theses.fr/2005TOU30197.
Here we describe the first evidence establishing that nuclei isolated from plant cells perceive physical stimuli (temperature and mechanical shocks) and convert them into specific changes in free calcium concentrations in the nucleoplasm. Mathematical modeling suggests that the nucleus behaves as a close system. Under these conditions, calcium movements in isolated nuclei depend upon calcium channel activities (InsP3 operated- or TRP-type channels) located in the inner nuclear membrane. Changes in free nuclear calcium are induced by sphingolipids some of them being activators of TRP channels. In intact cells, the cytosol controls the effects of sphingolipids (located in the nucleus) on the homeostasy of nuclear calcium. Collectively, our data strengthen the controversial idea that the nucleus is partially autonomous in terms of calcium signalling. They show further that different signaling pathways are connected in the nucleus
Petitdidier, Catherine. "Etude des modalités d'expression de certaines voies métaboliques de production d'arômes par des micro-organismes d'affinage des fromages à pâte pressée non cuite : précurseurs et systèmes enzymatiques impliqués dans le catabolisme des acides aminés". Clermont-Ferrand 2, 2002. http://www.theses.fr/2002CLF22334.
Leroy, César. "Oxalates de calcium et hydroxyapatite : des matériaux synthétiques et naturels étudiés par techniques RMN et DNP". Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066256/document.
In France, about 9.8% of the population suffer from urolithiasis. The treatment of kidney stones, composed of 72% of hydrated calcium oxalates (CaC2O4∙nH2O) with n = 1, 2, 3, represents almost 900 million euros in annual spending and it is therefore necessary to understand the in vivo formation of these stones. Here we propose a new approach in order to characterize kidney stones and have a greater understanding of their formation. Physicians primarily use FTIR techniques to determine the major phases present in a given pathological calcification. NMR methods appears suitable to determine more accurately the composition of these pathological calcifications. Very few NMR analyzes of kidney stones and synthetic analogues were conducted to date. In a first step, the three phases of calcium oxalate were synthesized by implementing original protocols. Analysis of the 1H, 13C CP MAS and MAS 43Ca ultra-high magnetic field spectra at natural abundance allow precise identification of the different phases and can be interpreted by taking into account the number of inequivalent crystallographic sites. The hydroxyapatite was studied in parallel as it may also appear in urolithiase. Finally, we show results obtained from DNP MAS at 100 K on the synthetic samples. The affinity of the biradical/solvent combination remains a limiting factor for heterogeneous materials such as those analyzed in this study. We have to be able to find a suitable combination for complex multi-component materials and to obtain an equivalent gain on all signals. In a last step, it is demonstrated that it is possible to transpose the methodological approach presented above to the study of kidney stones
Rousseau, Xavière. "Optimisation de l'utilisation de phosphore alimentaire chez le porc et le poulet en croissance". Thesis, Tours, 2013. http://www.theses.fr/2013TOUR4057/document.
The reduction of dietary phosphorus (P) and the optimisation of its utilisation by the animals represent major challenges for the sustainability of poultry and pig production. The development of new feeding strategies ensuring an efficient utilization of P appears crucial particularly during the finishing period. The present work contributed to redefine the requirement of P of the animals during this phase in conjunction with the other constituents of the feed matrix well-known to significantly impact on the overall utilisation of P (Ca, microbial phytase). Moreover, this work quantified the impact of Ca and microbial phytase on the digestive and metabolic flows of P. On one hand, generated knowledge helps developing mechanistic models simulating the fate of P in the scale of the animal and on the other hand new feeding systems to meet the challenges of sustainability
Erabit, Nicolas. "Caractérisation expérimentale et modélisation de la dénaturation et de l’agrégation de la beta-lactoglobuline au cours d’un traitement thermique de type industriel". Electronic Thesis or Diss., Paris, AgroParisTech, 2012. http://www.theses.fr/2012AGPT0094.
This work aims to model the formation of whey protein aggregates during continuous thermo-mechanical treatment (heat exchanger) with integration of the physicochemical properties (protein content and mineral content). This simulation work is supported by knowledge from literature and experimentation carried out in addition with literature.A two-step work was done at two scales. At laboratory scale, the samples were submitted to well controlled and almost homogenous thermo-mechanical treatments. This was used as data base to develop a mechanistic model of transformation for the irreversible aggregation of beta-lactoglobulin in solution in function of time/temperature/shear. This first step allows obtaining a model for one profile but not for a pilot-scale heat treatment. The hypothesis is that the dispersion of aggregate sizes in continuous heat treatment is partly due to distribution of residence times: proteins in the slowest parts of the fluid have more time to aggregate. Experiments were carried out on a continuous pilot of heat treatment
Cobert, Florian. "Processus et mécanismes physico-chimiques et biologiques responsables du fractionnement des isotopes du calcium". Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00762532.
Merdy, Patricia. "Etude de la complexation et de la sorption des cations Mn(II), Cu(II) et Fe(III° par une lignine et différents modèles moléculaires : influence de la teneur en ions calcium et carbonate présents dans les sols de craie". Reims, 2001. http://www.theses.fr/2001REIMS025.
Brazier, Jean-Michel. "Rôle des phases minérales des sols en tant que réservoirs de nutriments : approche expérimentale (abiotique), en milieu naturel et multi-isotopique (isotopes stables Ca-Sr)". Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAH005/document.
This PhD thesis examined the mechanisms of storage and release, from and elementary and isotopically point of view, of calcium (Ca) and strontium (Sr) onto or into mineral phases commonly encountered within soils (primary minerals, clay minerals, oxy-hydroxides, pedogenic carbonate). A robust δ88Sr measurements method had to be developed in the laboratory and validated by the measurement of international reference materials, mostly never measured in the literature. The results of this work show that Ca adsorption onto phyllosilicate minerals generates a quantifiable isotopic fractionation by preferential uptake of the light isotope (40Ca) under our experimental conditions when the minerals have a significant structural charge and specific surface area and/or an interlayer space open to hydrated cations adsorption. A study on rhizoliths in natural environment has also highlighted that the combination of Ca and Sr isotopes allows an effective tracing of sources and mechanisms in the problematic related to the storage of these two elements within soils
Zhang, Yan. "Modélisation du comportement élastoplastique d'une pâte cimentaire soumise à la dégradation chimique". Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10005/document.
Thesis presents elastoplastic modelling of cement-based materials coupledwith chemical degradation and mechanical damage. The emphasis is put on cementpaste subjected to compressive stresses. A short literature review is first presented on the mineralogical composition, chemical degradation mechanisms, basic mechanical behaviour and chemical-mechanical coupling. Based on this analyses and a series of experimental data obtained from uncoupled and coupled tests, an elastoplastic constitutive model coupled with chemical damage is first formulated. Two plastic mechanisms are taken into account; respectivelyrelated to deviatoric shearing and pore collapse. The chemical damage is identified as relative variation of porosity. Elastic and plastic properties are affected by chemical damage. Numerical simulations are compared with experimental data and good agreements have been obtained. The evolution of the chemical damage has been described by the generalized diffusion equation which is based on the mass balance equation and a phenomenological chemistry model. We have used finite element method to solve the generalized diffusion equation. Coupled chemical-mechanical tests have been simulated by the proposed model and we have also obtained satisfactory concordance. An extension of the model is finally proposed by including mechanical damage due to microcracks in order to describe brittle responses of material under tensile stresses and low confining pressures. An example of application to structural analysis with chemical degradation is presented. It has been shown that the proposed model describes correctly the main features of the mechanical behaviours of cement-based materials at different stress conditions with chemical degradation
Fall, Maïna. "Analyse du comportement d'achat des consommateurs canadiens en matière d'aliments fonctionnels : cas des oeufs contenant de l'oméga-3, des aliments à base de soja et le jus enrichi en calcium". Master's thesis, Université Laval, 2009. http://hdl.handle.net/20.500.11794/20939.
Claveau, David. "Activités antimicrobiennes de différentes préparations de ZnO, CaO et MgO et leur potentiel comme agents de conservation dans les jus de fruit". Thesis, Université Laval, 2009. http://www.theses.ulaval.ca/2009/26675/26675.pdf.
Issa, Sabin. "Fonctionnalisation de la surface du titane pour les implants dentaires". Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1075/document.
The objective of this thesis is to create new nanostructured surfaces with bioactive coatings and to study theirs physicochemical properties in order to develop better dental implants designs and promote their osseointegration. This functionalization was performed in two steps; starting by the nanostructuration of TiO2 surface by anodisation to create reactive sites on the edges of titanium nanotubes which acts as points of “attachment" to bioactive coatings. The second step was the surface chemical modification by coating the nanostructured surface with bioactive coatings of calcium phosphate (CaP) and strontium doped calcium phosphate (Sr.CaP). This coating was performed by pulsed electrodeposition. The physicochemical characterization by XPS, SEM and IR showed that doping with Sr promotes a non-apatitic compound similar to DCPD or DCPA (Dicalcium Phosphate Dihydrate or Anhydrous), while undoped CaP coating looks like an amorphous apatite-like compound ACP. The addition of strontium has the double advantage of optimizing the cellular multiplication and of giving an inorganic phase with bio-performance better than apatitic compounds. We also evaluated the adsorption proprieties of these functionalized surfaces by investigating the adsorption of proteins (BSA). This adsorption was performed onto tblank nanotubes, nanotubes coated with CaP and Sr doped CaP and evaluated according to deposition time and to the pH value of the solution that affect both protein and surface charge. The kinetic and structural evaluation reveals different adsorption geometries according to pH and adsorption time and also according to the chemical nature of surface. Such results of protein adsorption and conformation may form a database to understand and control protein activities and reactions with living body when used for dental implants system
Hyvert, Nicolas. "Application de l'approche probabiliste à la durabilité des produits préfabriqués en béton". Toulouse 3, 2009. http://thesesups.ups-tlse.fr/526/.
Atmospheric carbonation is one of the most significant degradation factors for the durability of reinforced concrete structures. Carbonation relates to the diffusion of CO2 in the atmosphere through the concrete pores and to the dissolution of the hydrates, especially the portlandite, which supplies the reserve of concrete basicity. When portlandite is totally consumed, the pH value decreases to a value less than 9. It corresponds to the conditions allowing the corrosion of the reinforced bars which are protected only under a high pH level. The aim of this work is to carry out a probabilistic physico-chemical modelling of carbonation, taking into account the industrial requirements and being easy to utilize in a probabilistic design of the concrete cover. A wide experimental campaign was conducted in order to propose a practical model of carbonation for its efficient usage in the industry of precast concrete. From the cement nature, the concrete composition, the curing and thermal treatment characteristics, and one carbonation test (or at least the compressive strength), the model can determine the carbonated thickness for different pressures of CO2. Further, it allows the reliability index with respect to the initiation of corrosion to be estimated thanks to a link with a probabilistic algorithm. Following the scheme of checking the reliability level as recommended by the European regulation Eurocodes for structural design, the benefit of a probabilistic approach in the durability design of a concrete structure has been then emphasized
Teh, Winh-Chhunn. "L’épidémie des calculs rénaux. Approche physiopathologique alliant RMN à l’état solide et IRM". Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS492.
Urolithiasis is a major public health problem especially in Western developed countries. Increasingly young populations are affected. In France, the annual expenses related to drug treatments, surgical procedures and possible dialysis treatments approach 800 million euros. Pathological calcifications like the kidney stones are extremely complex compounds to characterize and at present, their formation in situ within the human body is still shrouded in mystery, despite numerous in vivo and ex vivo clinical studies. The complexity is above all of a chemical nature, the composition of each kidney stone being particular. A kidney stone is generally composed of mineral and organic phases thus constituting an inorganic organic hybrid derivative (on several scales of size). Two phases of hydrated calcium oxalates are overrepresented, namely whewellite, CaC2O4.H2O, and weddellite, CaC2O4.2H2O. The second most represented family corresponds to calcium phosphates, of which carbonated hydroxyapatite (HAp) is a major representative. The complexity of kidney stones is also structural. At present, it is particularly difficult to characterize the interpenetration of organic and inorganic networks and above all, at what size scale. In addition, the phases present can undergo transformations over time, which make the analysis of associated pathologies even more complicated. Kidney stone formation in vivo is an exciting but challenging subject. Lithogenesis generally corresponds to an association (of the agglomeration type) of one or more inorganic crystals within an organic matrix (which may contain proteins, lipids, unsaturated fatty acids or even triglycerides). It is considered that the formation of a stone comes from the succession over time of several events: the supersaturation of the urine (which is obviously pH dependent), the germination, the growth and the aggregation of the crystals, the retention of the crystals via the process of adhesion in a cavity of the nephrons for example, and finally the final growth which can lead to a surgical act. Some consensus exists on the early stages of kidney stone formation. Following observations made post-mortem by the surgeon Randall, it has been proposed that the first nucleus to form is of an apatitic (carbonated) nature. This is what is now called the Randall’s plaque. From Randall's plaque, the kidney stones are then supposed to grow, their final chemical composition depending on the anionic and cationic contributions, the metabolism and the possible taking of long-term drug treatments. Finally, many characterization techniques have been implemented for the detailed study of the structure of pathological calcifications, both in imaging, diffraction and spectroscopy. Curiously, solid-phase NMR has been little implemented. In general, standard MRI as practiced in hospitals is almost never implemented for the study of kidney stones. In a 2016 review reviewing the state of the art of stone analysis methods, Brisbane devotes only a short paragraph at the very end of the article to MRI and speaks of a "non-specific void" about of the image of a calculation. The heart of this research work focuses on the characterization by DNP (Dynamic Nuclear Polarization) and magic angle spinning imaging (MAS MRI) of the Randall’s plaque, and more generally of the calcium oxalate/phosphate phases and kidney stones. The goal is to ultimately propose interesting avenues for hospital practitioners regarding the diagnosis of nephropathologies
Gonzalez-Barrios, José Luis. "Eaux d'irrigation et salinité des sols en zone aride mexicaine : exemple dans la "Comarca Lagunera"". Montpellier 2, 1992. http://www.theses.fr/1992MON20235.
Auclerc, Apolline. "Impact d'amendements calco-magnésiens sur la diversité des macroinvertébrés de sols forestiers et sur certains processus fonctionnels associés. Cas du massif vosgien (nord-est, France)". Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0056/document.
The use of liming (Ca-Mg) on acidified forest can be interesting to counteract soil acidification and loss of nutrients caused by decades of acid atmospheric deposition. In this context, the aims of this work were to assess liming effect on (i) taxonomical diversity and community structure of soil macro-invertebrates and on (ii) two associated functional processes related to earthworms: soil structuration and humus evolution. The PhD project was realised in three sites from the Vosges mountains (North-eastern, France): two forest mountain catchments (one lying on sandstone and the other on granite) limed in 2003 and the public hill forest of Humont at a lower altitude limed in 1991 and 2008. Results showed that 4 years after liming in mountain forest, the total abundance of macro-invertebrates decreased, while the species richness were similar. However, the community structure strongly differed, and less than 50% of the species were common to limed and control sites. Moreover, 43 species appeared to be indicators of liming. Predator taxa abundance decreased whereas the detritivorous were favoured by lime addition. The in vitro experiments showed a positive effect of liming on soil structuration by earthworm activities (cast production and burrowing activities). In the Humont forest, liming at medium-term (4 years) and long term (20 years) have an important effect on the Aporrectodea velox population, an endemic vosgian species. Related to its high biomass, this increase strongly improved soil physicochemical parameters such as soil structure and humus morphology