Дисертації з теми "Méthodes RMN"
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Heude, Clément. "Développement de nouvelles méthodes analytiques dans l'agroalimentaire par RMN." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAD038/document.
Most of the current analytical and quality control methods in the food industry are based on a targeted approach, with an upstream definition of the intended contaminants, and may fail to detect some frauds or contaminations of genuine products. It is around this issue that the Agrifood GPS (Global Protection System), of which this thesis is part of, has been initiated. This project aims at developing new holistic analytical methods (untargeted) in order to ensure the integrity of the foodstuff analyzed. This thesis manuscript gathers the results obtained on semi-solid foodstuffs (mainly fish), by High Resolution Magic Angle Spinning NMR, and on caviar extracts by high resolution liquid-state NMR (HR NMR). First of all, it presents a rapid method to evaluate fish freshness and quality based on the determination of two chemical indicators (the TMA-N and the K-value) and the results of a fish texture study through the measurement of the transverse relaxation time (T2) of water in muscle tissues, both by HR-MAS NMR spectroscopy. Thereafter, are presented the results of the work carried out on the determination of the geographical origin of caviar using the metabolic profile acquired by liquid-state NMR spectroscopy and multivariate statistical analysis in the context of the PGI (Protected Geographical Indication) status for the Aquitaine producers, and on the degradation study of caviar during its storage in a fridge
Mafra, Luis Miguel Monteiro. "RMN de matériaux cristallins inorganiques-organiques hybrides : méthodes et applications." Caen, 2006. http://www.theses.fr/2006CAEN2033.
In the first part of this thesis, I present some basic NMR concepts, focusing on the 1H homonuclear decoupling, based on Frequency-Switched Lee-Goldburg (FSLG) methods. The optimisation of the experimental conditions which afford high-resolution two-dimensional NMR spectra is discussed. In the second part, a number of NMR case studies centred on inorganic-organic hybrid materials are described. These solids are rich in 1H nuclei and their 1H NMR spectral lines are usually broadened homogeneously by the strong homonuclear dipolar couplings. Here, I show that FS-LG decoupling is a very powerful and robust technique to study these materials, allowing the acquisition, under 1H highresolution, of 2D homo and heteronuclear correlation NMR spectra. Dipolar recoupling techniques such as BABA, POSTC7 and RFDR were also employed. When used in tandem with X-ray diffraction data, the information forthcoming from these NMR studies provides a clear structural picture of the hybrid materials. In the third part of this thesis, I introduce a new NMR method to study I = 3/2 and 5/2 quadrupole nuclei in powdered solids. A “multiplex” phase cycling procedure is employed, which allows recording separately each coherence transfer pathway (CTP), for post acquisition, signal selection and processing. This new method allows performing multiple experiments with distinct CTPs, during the timespan of a single experiment. Finally, I demonstrate that coupling the so-called “soft-pulse added mixing” (SPAM) and “double-multiplex” phase cycling allows a considerable reduction in the experimental time as compared to the simple multiplex method
Hamdoun, Ghanem. "Nouvelles méthodes RMN pour la caractérisation structurale et dynamique des agrégats organolithiés." Rouen, 2014. http://www.theses.fr/2014ROUES018.
Because of their high reactivity and diversity, alkyllithium compounds are important reagents for both organic and polymer chemistry. In solution, these species exist as hexamers, tetramers, trimers, or dimers forms, depending on temperature, concentration, solvent, and on the nature of the alkyl chain. In the presence of oxygen, they lead to many kinds of mixed alkyllithium/lithium alkoxide aggregates in solution as they react with oxygen to give alkoxides and peroxides. The formation of those mixed aggregates, whose properties may be quite different from those of either pure component, affects substantially the reactivity of the alkyllithium coumpounds. The main objective of this work was to determine the structure, the solvation and aggregation states of pure alkyllithium compounds (Et6Li, Pr6Li, Bu7Li) and mixed alkyllithium/lithium peroxide aggregates, in THF, at low temperature. We have shown that these alkyllithium compounds existed as tetramer, and dimer forms in exchange within a dissociative mechanism. In the presence of the corresponding lithium alkoxide, a mixture of 5 tetra-solvated tetramers is formed. 1H Pure shift DOSY NMR was used for the characterization and the quantitative estimation of degree of solvation and aggregation state of n-butyllithium/lithium n-butoxide mixed aggregates. In the second part of this work, we have thought to use a new NMR method for the measurement of very weak 6,7Li-6,7Li scalar coupling. The strategy we used consisted in doubling the spin-spin splitting without altering the line width by the introduction of a scale factor into a 2D NMR J-resolved like experiment, named “SERF”. For more complex systems we have shown that the CT-COSY experiment in lithium 7 observation could be an alternative tool, resulting in accurate measurements of J7Li-7Li
Stratmann, Dirk. "Nouvelles méthodes pour l'attribution de spectres RMN de protéines de structure tridimensionnelle connue." Paris 6, 2008. http://www.theses.fr/2008PA066667.
A prerequisite for any protein study by NMR is the assignment of the resonances from the 15N-1H HSQC spectrum to their corresponding atoms of the protein backbone. A new type of assignment strategy exploits the information given by an already available 3D structure of the same or a homologous protein. Up to now, the algorithms that have been developed around this strategy have two important drawbacks: they cannot guarantee the accuracy of the assignment and they are not applicable to large proteins. First is shown that the use of residual dipolar couplings (RDC) for the structure based assignment can be problematic, especially the estimation of the alignment tensor is difficult. A novel structure based assignment approach, called NOEnet, is presented here. NOEnet is not based on RDCs but on Nuclear Overhauser Effects (NOEs). RDCs, chemical shifts (CS) and almost any kind of data can be included in NOEnet through a general filter approach. NOEnet exploits the network property of unambiguous HN-HN NOE constraints to realize an exhaustive search of all matching possibilities of the NOE network on the structural one. Its efficient complete search algorithm ensures the correctness of the assignment results. NOEnet has been successfully tested on several proteins up to 28 kDa, using only NOE data or a combination of NOE, RDC and CS data
Negrevergne, C. "Controle quantique grâce aux méthodes de RMN. Application à la simulation de systèmes quantiques." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2002. http://tel.archives-ouvertes.fr/tel-00004371.
Les methodes de Resonance Magnetique Nucleaire en solution permettent d'initialiser, de manipuler et d'observer l'etat d'un systeme de spins 1/2 couples. ces methodes ont ete utilisees pour realiser experimentalement un petit processeur d'information quantique (QIP pour "Quantum Information processor") pouvant executer une centaine d'operations elementaires. un des themes principaux de ce travail a ete de concevoir, d'optimiser et de valiser des sequences d'impulsions necessaires pour "programmer" ce QIP.
ces techniques ont ete utilises pour executer un algorithme quantique de simulation des systemes anyoniques. des resultats experimentaux pour la determination des energies propres et de fonctions de correlation d'un systeme illustratif de fermions sur reseaux ont ete obtenus permettant de valider l'algorithme de simulation dans son principe et son execution experimentale.
Recht, Raphaël. "Mise au point de méthodes de détection d’interaction ligand-macromolécule par RMN du 19F." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAJ055/document.
Biological interactions are under the control of complex mechanisms, across different scales, in time of in size. It is particularly true for the ribosome, a nucleoprotein responsible for the mRNA translation into proteins, and thus, a primary therapeutic target. The size of the prokaryotic 70S ribosome (2.4 MDa) is a problem for the application of classical ligand screening method. During my thesis, I explored using fluorine NMR to characterize the interaction between ligands and the prokaryotic ribosome. This strategy was motivated by new detection approaches that can combine NMR (Nuclear Magnetic Resonance) versatility with the fluorine atom properties. The 19F atom is perfectly suited for NMR, with its gyromagnetic ratio close to the proton one and its isotopic abundance of 100%. Moreover, the fluorine is absent from natural compounds. Finally, the physicochemical characteristics of fluorine are well exploited in the pharmacopeia (a fourth of all antibiotics has a fluorine moiety)
Negrevergne, Camille. "Contrôle quantique grâce aux méthodes de RMN : application à la simulation de systèmes quantiques." Bordeaux 1, 2002. http://www.theses.fr/2002BOR12593.
Izquierdo, Marguerite. "Caractérisation spectrale en spectroscopie RMN in vivo : contribution au développement de méthodes physiques d'investigation." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10153.
Sahnoun, Souleymen. "Développement de méthodes d'estimation modale de signaux multidimensionnels. Application à la spectroscopie RMN multidimensionnelle." Phd thesis, Université de Lorraine, 2012. http://tel.archives-ouvertes.fr/tel-00788022.
Sahnoun, Souleymen. "Développement de méthodes d'estimation modale de signaux multidimensionnels. Application à la spectroscopie RMN multidimensionnelle." Electronic Thesis or Diss., Université de Lorraine, 2012. http://www.theses.fr/2012LORR0169.
This thesis aims at the developpement of modal analysis algorithms for multidimensional signals (R-D) presenting resolution and numerical complexity problems. A multidimensional signal of dimension R is the superimposition of products of R monodimensional sinusoids. The intended application is NMR spectroscopy. Firstly, after a state-of-the-art on the so-called ''algebraic'' estimation methods, we propose a parametric method based on tensors. It uses the multidimensional tensor lattice of the R-D modal signal and exploits the eigenvectors structure of the signal subspace obtained using a higher-order singular value decomposition (HOSVD). Unlike most tensor-based eigenvalue approaches, modes estimated by the proposed method are automatically paired, thus it avoids a separate pairing step and joint diagonalization. Secondly, the multidimensional modal estimation problem is formulated as a sparse approximation problem in which the dictionary is obtained by the discretization of complex exponential functions. To achieve good spectral resolution, it is necessary to choose a very fine grid, which leads to handling a large dictionary with all the underlying computational problems. Hence, we propose a novel method that consists in combining a sparse approximation and a multigrid approach on several levels of resolution. The approach is demonstrated using several 1-D and 2-D examples. In addition, the influence of the initial dictionary on the algorithm convergence is also studied. The developed methods are then applied to estimate 1-D and 2-D NMR signal parameters. To reduce the computation cost in the case of large bidimensional signals, we also propose an approach exploiting the simultaneous sparsity principle to estimate the coordinates of the modes on each dimension. The procedure involves two 1-D sparse approximations followed by a 2-D modes painring step
Girard, Jean-Francois. "Contribution à l'Hydro-Géophysique : Développements et Applications de la Résonance Magnétique Protonique et des Méthodes Electromagnétiques." Habilitation à diriger des recherches, Université de Strasbourg, 2010. http://tel.archives-ouvertes.fr/tel-00472209.
Desvaux, Hervé. "Exploration de nouvelles méthodes de RMN pour les études structurales et dynamiques dans les liquides." Paris 6, 1993. http://www.theses.fr/1993PA066069.
Rouyer, Virgile. "Polyaniline : hydratation, mise en oeuvre par voie solvant, et durabilité : approches RMN et méthodes diffusives." Université Joseph Fourier (Grenoble), 1999. http://www.theses.fr/1999GRE10075.
Raingeval, Claire. "Méthodes RMN pour la découverte de nouveaux ligands ciblant les récepteurs couplés aux protéines G." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1215/document.
G protein-coupled receptors (GPCRs) are the largest class of membrane proteins in the human genome. GPCRs act as cell surface signalling proteins and respond to a variety of external signals. They play a pivotal role in many physiological functions and are therefore associated with a multitude of diseases, including cardiovascular, metabolic, neurodegenerative, psychiatric, and oncologic diseases. The 2012 noble Prize in Chemistry was awarded jointly to Robert J. Lefkowitz and Brian K. Kobilka for studies of GPCRs, highlighting the importance of this protein superfamily. GPCRs constitute also the most important family of drug targets in the human body, with 30% of current drugs acting on GPCRs. However, drug discovery targeting GPCRs remains difficult, owing to the restricted structural information on GPCRs related to the instability of these proteins when isolated from their cell membrane environments. There is also a lack of knowledge for the structural and functional consequences of the interactions of small-molecule compounds with GPCR. The aim is to develop methods to study and characterize a full GPCR solubilized in detergents or in native lipid bilayers, both in its free form and in small molecule bound forms, using liquid-state NMR experiments. The aim is to develop NMR-based approaches that will strongly impact the structure-based drug discovery process for the GPCR family
Guerroudj, Feryal. "Dispositifs et méthodes RMN pour la caractérisation des écoulements et des transferts en milli-canaux." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0273.
Our study aims to implement, with a low-cost methodology, specific devices to study flows and transfer phenomena in milli-fluidic systems and to optimize NMR/MRI methods for their characterization.Two milli-fluidic applications have been developed. The first one consists in the study of the flow regime and hydrodynamic instabilities occurring in micromixers. The second one in the study of the growth of a biofilm in a capillary of submillimeter dimensions and the characterization of the hydrodynamics of the flow in presence of this biofilm. For each application, a specific device was set up, including the milli-fluidic system and the radio frequency (RF) coil adapted to the geometry and dimensions of the system. The milli-coils were fabricated by etching on flexible copper/Kapton® substrates. With the considered geometrical parameters, RF simulations have shown that milli-coils produce an intense and homogeneous field and MRI measurements demonstrate an improvement of the signal-to-noise ratio compared to the commercial MicWB40 probe, which allows the detailed analysis of the above mentioned milli-fluidics phenomena
Bordelois, Boizán Alejandro. "Développements de méthodes d'acquisition et de traitement du signal robustes aux défauts du champ magnétique pour la spectroscopie localisée par RMN." Phd thesis, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-00914306.
Diop, Aboubakar. "Méthodes de traitement du signal pour la quantification en spectroscopie RMN : estimateur de signal et prédiction linéaire." Lyon 1, 1993. http://www.theses.fr/1993LYO10131.
Cherni, Afef. "Méthodes modernes d'analyse de données en biophysique analytique : résolution des problèmes inverses en RMN DOSY et SM." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAJ055/document.
This thesis aims at proposing new approaches to solve the inverse problem in biophysics. Firstly, we study the DOSY NMR experiment: a new hybrid regularization approach has been proposed with a novel PALMA algorithm (http://palma.labo.igbmc.fr/). This algorithm ensures the efficient analysis of real DOSY data with a high precision for all different type. In a second time, we study the mass spectrometry application. We have proposed a new dictionary based approach dedicated to proteomic analysis using the averagine model and the constrained minimization approach associated with a sparsity inducing penalty. In order to improve the accuracy of the information, we proposed a new SPOQ method based on a new penalization, solved with a new Forward-Backward algorithm with a variable metric locally adjusted. All our algorithms benefit from sounded convergence guarantees, and have been validated experimentally on synthetics and real data
Schanda, Paul. "Développement et applications de méthodes RMN rapides pour l'étude de la structure et la dynamique des protéines." Phd thesis, Grenoble 1, 2007. http://www.theses.fr/2007GRE10198.
Multidimensional (nD) NMR is the method ofchoice for atom-resolved studies ofprotein structure and dynamics in solution. Among its current limitations are the long acquisition times required, translating to experimental times of several days or weeks for the set of experiments required for structural studies of proteins. Furthermore, real-time studies of kinetic processes occurring on a seconds time sc ale are inaccessible to standard nD NMR. This thesis is concerned with the development of fast nD NMR techniques based on longitudinal relaxation optimization. It is shown that 2D 1H-15N (3D 1H-15N-13C) correlation spectra can be obtained in only a few seconds (few minutes) of acquisition time for samples at millimolar concentration. Ln addition, the longitudinal relaxation optimized methods, when combined with alternative data sampling such as spatial or Hadamard encoding, can yield site-resolved 2D1H-15N correlation spectra in acquisition times down to one second. Applications of fast 2D methods to the study ofprotein folding and unfolding are shown. This thesis also presents a longitudinal relaxation optimized method for the sensitivity-enhanced measurement ofresidual dipolar couplings between amide protons, as well as a fast and simple experiment for the characterization of protein samples, which can be very useful in the context of screening of sample conditions
Dabachi, Jamal. "Etude par RMN du solide multi-noyaux et modélisation des paramètres RMN de fluorures et d’oxyfluorures inorganiques." Thesis, Le Mans, 2017. http://www.theses.fr/2017LEMA1006/document.
This thesis focuses on the structural study of fluorides and oxyfluorides by combining solid state NMR, X-ray diffraction and PAW/GIPAW calculations of NMR parameters. The first part is devoted to the study of compounds of the KF-YF3 binary system. Linear correlation between experimental isotropic chemical shift (delta iso) and calculated isotropic shielding (sigma iso) values have been established, for 19F, 89Y and 39K, from assignments of NMR lines to crystallographic sites. These correlations lead to satisfactory agreements. In the case of 19F and 89Y, the link between NMR parameters and environment has been established. The calculated 39K NMR parameters allow satisfying reconstructions of the experimental complex spectra. The second part is dedicated to the study of the two ordered phases of LaOF. The optimizations and bond valence calculations showing that the atomic positions of F and O should be interchanged in both the phases, their structures have been refined. The agreement between experimental and calculated NMR parameters of 19F and 139La validates our structural models. Finally, the isotypic and disordered MO2F (M = Nb, Ta) compounds, since the O and F atoms occupy the same anionic site, have been studied. It is shown that the aqueous solution synthesis leads to hydroxylated and lacunary compounds, whose formulations have been determined by combining 19F NMR, XRD and TGA. The solid state synthesis enables to obtain pure compounds. DFT calculations were carried out on optimized 3 × 3 × 3 supercells that respect the partial order -M-O-M-O-M-F-. The good agreement between experimental and calculated NMR parameters of 19F validates the proposed model
Thureau, Pierre. "RMN [Résonance Magnétique Nucléaire] DOSY [Diffusion Ordered SpectroscopY] : comparaison des méthodes de traitement et application à l'échange chimique." Aix-Marseille 1, 2006. http://www.theses.fr/2006AIX11032.
This thesis can be viewed as the state-of-the-art of Diffusion Ordered NMR SpectroscopY (DOSY). More precisely we described various approaches to analyze the data so that the information obtained from the mixture analysis can be maximized. The limitations of the different methods and the perturbation arising from chemical exchange are also discussed. In the first part of the manuscript, we describe the numerical problems arising from NMR diffusion data processing and compare several methods available in the literature for avoiding such problems. In addition, pulse sequences and methodologies, will be discussed herein. Finally, we describe the perturbation induced by the chemical exchange on NMR diffusion experiments and how this perturbation can be used to extract precisely the exchange rate constant. With the help of these techniques, the hydration properties of the pyrimidine bases have been probed
Schanda, Paul. "Développement et applications de méthodes RMN rapides pour l'étude de la structure et de la dynamique des protéines." Phd thesis, Université Joseph Fourier (Grenoble), 2007. http://tel.archives-ouvertes.fr/tel-00181457.
Cette thèse présente aussi une nouvelle expérience RMN qui permet d'évaluer rapidement la qualité d'un échantillon de protéine, et une nouvelle méthode pour mesurer des couplages dipolaires résiduels entre protons amides avec une meilleure sensibilité que les méthodes existantes.
Cutuil, Thomas. "Etude du repliement des protéines par RMN temps réel et autres méthodes biophysiques : l'exemple de la Beta-2-microglobuline." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00849137.
Caspary, Olivier. "Applicabilité des méthodes d'analyse spectrale à haute résolution fréquentielle." Nancy 1, 1995. http://www.theses.fr/1995NAN10004.
Diomande, Gbe Gondo Didier. "Contribution des méthodes spectroscopiques et isotopiques à la caractérisation géographique et phénotypique du cacao." Nantes, 2014. https://archive.bu.univ-nantes.fr/pollux/show/show?id=fd4e7f5d-6094-444e-b12a-043f6c632eb5.
The cocoa tree (Theobroma cacao L. ) is a plant of the family Sterculiaceae. The fruit, called the pod, contains beans that are used in the manufacture of chocolate. Fraudulent production practices are making consumers increasingly suspicious both of the sanitary quality of foodstuffs and of the origin of production (organic, GM, etc. ). Faced with this problem, the new European legal ruling 178/2002, effective since 1 January 2005, imposes traceability for foodstuffs. This thesis is positioned within this context. The analysis of the multi-isotope content (15N, 13C) of 61 samples of cocoa obtained from 22 countries, of which 37 samples are from the Ivory Coast, has been carried out. By statistical analysis of the data, it is shown that the isotopic parameters δ15N and δ13C for the whole cocoa beans, and those from different parts of the bean, are responsible for the discrimination found between samples from different continents, from three villages in the Ivory Coast, and between the varieties Forastero and Trinitario. Fermentation of cocoa is the process that most influences the quality of the beans. A study of the influence of fermentation on the isotopic composition in δ15N and δ13C showed either enrichment or impoverishment for the bean and for different parts of the bean, with the exception of theobromine, for which no isotopic fractionation was found. As a result, theobromine was used in isotopic quantitative 13C NMR as molecular probe for the characterization of the geographical origin of cocoa. A methodology has been developed which allows the measurement of the intramolecular 13C distribution in theobromine with sufficient accuracy, subsequent to its transformation into caffeine. New parameters were obtained which not only allowed confirmation of the distinct geographical origins of different cocoa samples, but also to differentiate cocoa from products containing caffeine (tea and coffee). An exploratory study was also carried out measuring the 18O content of theobromine by irm-MS, with the same objective in mind. Finally, cocoa butter, which is one of the most important matrices in the beans, was analyzed by 13C NMR in the framework of the methodology “metabolomics”, notably targeting the glycerol
Shen, Ming. "Nouvelles méthodes de RMN des solides pour les corrélations homo- et hétéro-nucléaires et l’observation des noyaux de spin 1." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10066/document.
My PhD work has focused on the development of advanced solid-state NMR methods. We have notably developed homo-nuclear correlation methods compatible with high MAS frequencies and high magnetic fields. First, we have shown that the robustness of finite pulse RadioFrequency Driven Recoupling (fp-RFDR) technique can be improved by the use of nested (XY8)41 super-cycling. Such method has been employed to probe 13C-13C and 31P-31P proximities in solids. Second, we have also introduced a second-order proton-assisted 13C-13C correlation experiment, denoted “Second-order Hamiltonian among Analogous nuclei plus” (SHA+), to observe long-range 13C-13C proximities in solids at fast MAS and high magnetic field. During my PhD, we have also improved the heteronuclear correlation methods for the indirect observation of 14N nuclei via protons. We have shown that the spectral resolution along the indirect dimension of proton-detected Heteronuclear Multiple Quantum Correlation (HMQC) spectra can be enhanced by applying homonuclear dipolar decoupling schemes during the t1 period. We have also proposed the use of centerband-selective radio-frequency (rf) pulses for the excitation of 14N nuclei in 1H{14N} HMQC experiment. The efficiency of these centerband-selective pulse is comparable to that of broadband excitation given the rf field delivered by common solid-state NMR probes. The last part of my PhD focuses on the improvement of the quadrupolar echo sequence for the acquisition of the 2H spectra of solids. The distortions of such spectra were reduced by the introduction of novel composite pulses
Trébosc, Julien Mathieu. "Méthodes d'analyse structurale par RMN haute résolution des noyaux quadripolaires et mesures des couplages à travers les liaisons et l'espace." Lille 1, 2003. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2003/50376-2003-317-318.pdf.
Kovrlija, Ruzica. "Développement de nouvelles méthodes de RMN pour la mesure quantitative et multi-échelles des transferts d’eau dans des matrices à base d'amidon." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1B003/document.
Water migration is a generic subject in various fields, the analysis of which makes it possible to better understand the rheological, sensory and conservation properties of products over time. The contributions of relaxation and NMR micro-imaging in the field are broad and of major interest in view of the non-invasive, non-destructive and quantitative characteristics of these methods, which can be used while the product is under processing. Two methodologies have been developed to study the transfers in a wide range of time and length. The first consisted in implementing new methods of acquisition and processing of the NMR signal in 2D at low-field (20 MHz) to correlate not only the relaxation times T1 and T2 , but also the translational diffusion coefficients D and T2 on starch-water model samples from various botanical origins (wheat, potato and waxy corn). The 2D measurements have proved sufficiently robust to quantify the transfers of protons from water and starch polymers during their swelling, gelatinization and retrogradation. A complementary approach by MR micro-imaging (at 500 MHz) consisted in measuring, over time, the water uptake on several millimeters in an extrudate of potato starch containing glycerol. The diffusion transport of the water and the rate of the extrudate swelling were quantified at 22°C for more than 20 hours
Klein, Mathieu. "Développement de méthodes RMN/IRM dédiées à l'étude des phénomènes de transport dans les piles à combustible à membrane échangeuse de protons." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0274/document.
This work focuses on the development of MRI/NMR methods dedicated to the characterization of water transport properties in a polymer membrane used in PEMFC. Radiofrequency coils are used to (1) study water self-diffusion coefficient in uniaxially stretched membranes and (2) spatially and temporally resolved measurements of the water distribution through the membrane. These measurements provide information about the influence of the polymer structure on water transport properties and also on real-time water distribution through the membrane in various humidity conditions. The water diffusion anisotropy is intimately linked to the structural order of the polymer. The steady-state and transient profiles of water content through the membrane indicate that mass transfer is limited by the interfacial resistances and mainly by the polymer relaxation during sorption
Dang, Phuc Hung. "Développement d’aimant bas champ pour RMN Portable : Conception et construction." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0007/document.
This thesis focuses on the development of a magnet system for NMR applications with high homogeneity while maintaining the static magnetic field B0 as high as possible (100 ppm, 0.12T). Due to the application goals, the magnet dimensions are predefined as well as those of the region of interest according to the size of the used permanent magnets. Such system is dedicated to biomedical and agroalimentary applications. The goal of this research has been firstly, the discussion of parameters of magnetic materials which are essential to the construction of portable NMR magnets, and then the choice of the permanent magnet material the “NdFeB” that was explained. A compromise between the portability, price and the sensitivity has led to the design of a prototype of portable NMR magnet with a simple system of arrangement of 24 permanent magnets. The magnetic field and the homogeneity of the system were calculated and simulated by using ANSYS software and these results were correlated to those obtained by the Radia software. A new shim method has been used to increase the homogeneity and correct the field B0 imperfection. Based on these results, a prototype was realized. The results of the magnetic field strength and homogeneity obtained by measurements are in good correlation with the results obtained by simulation. Sufficient accuracy was reached to take into account and correct errors due to manufacturing tolerances of the magnets. Another magnet system based on Mandhalas configuration (Magnet Arrangement for Novel Discrete Halbach Layout) was studied. The comparison between two configurations made from circle and square magnets was performed by 2D simulation (using three criteria: mass, homogeneity and the magnetic field strength). The Mandhalas made from circle magnets give better results (0.32 T, 178 ppm). The 3D simulation was carried out to evaluate the total system. From these results, a passive shim system was also used in this case and the homogeneity significantly increases
Kocevar, Gabriel. "Développement de méthodes d’IRM avancées pour l’étude longitudinale de la Sclérose en Plaques." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1057/document.
While conventional MRI is the reference tool for the diagnosis and monitoring of MS, it remains only moderately correlated with the patient’s clinical status. In order to better characterize pathological alterations occurring in MS, we use in this work non-conventional MRI techniques, namely magnetic resonance spectroscopy (MRS) and diffusion MRI.A first weekly follow-up revealed the sensitivity of the diffusion metrics and the specificity of the SRM to detect the initial processes of lesion formation.A second follow-up revealed changes in diffusivity in several white matter fiber bundles, including a decrease in fraction of anisotropy and an increase in radial diffusivity, worsening with advancing disease and more marked in the progressive forms.Finally, the application of graph theory allowed to characterize the brain connectivity in the four clinical forms and to study their evolution. This study allowed us to highlight alterations in all the four clinical phenotypes, including a decrease in the cerebral network density, more marked in the progressive forms of the disease and tending to increase with its progression.This work shows the sensitivity of advanced MRI techniques for the characterization of pathological alterations and their evolution in MS
Michelotti, Alessia. "Développement de méthodes synthétiques pour le marquage au carbone-13 et deutérium de molécules endogènes pour des applications en DNP-IRM et RMN." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLV032.
Hyperpolarized 13C magnetic resonance imaging (13C-MRI) is a promising emerging tool to follow the metabolic routes in vivo in view of early stage detection of cancer. Optimization of the sensitivity of the MRI measurement requires injection of carbon-13 or deuterium labelled endogenous molecules. In this context, sodium L-[1-13C,U-D] lactate was individuated as a promising probe for the detection and prediction of treatment-response in patients with prostate cancer. We realized the first chemical synthesis of such probe starting from L-[1-13C] alanine by developing two distinct strategies for the selective deuteration of the position C2 and C3. The method of C2 deuteration relies on the technique of the metal-catalyzed hydrogen-deuterium exchange and can be applied to the synthesis of several deuterated amino-acids to an industrial-scale. The method of C3 deuteration was realised by Pd(OAc)2 catalyzed C-H activation. It provides a unique route to obtain amino-acids selectively deuterated in position C3. We also developed a robust route for the 13C labelling of the C1 position of L-alanine from acetaldehyde and K13CN by a modification of the Strecker’s synthesis. By using deuterated acetaldehyde, a scalable synthesis of L-[1-13C,U-D] lactate could now be possible
Cots, Olivier. "Contrôle optimal géométrique : méthodes homotopiques et applications." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00742927.
Castets, Aurore. "RMN de matériaux paramagnétiques : mesures et modélisation." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2011. http://tel.archives-ouvertes.fr/tel-00664817.
Li, Yixuan. "Développement de nouvelles méthodes de RMN des solides : nouvelles séquences d’impulsion pour les expériences de corrélation hétéronucléaires et traitement par covariance des expériences homonucléaires." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10065/document.
This thesis focus on the development of novel Solid-State Nuclear Magnetic Resonance (SS-NMR) methods. The proposed methods are compatible with high magnetic fields and fast MAS. Main achievements comprise :(1) the new pulse sequence (PT-HMQC) for heteronucler experiments. The major limitation of HMQC experiments is their lack of sensitivity, especially involving quadrupolar nuclei with short T2 values. We propose a simple and robust strategy by manipulating the populations of the satellite transitions (ST) during the mixing time, to accelerate the rate of coherence transfer, and enhance the sensitivity of J-HMQC experiments with indirect detection of the quadrupolar nucleus. With the introduction of new shape pulses (quadruple sweeps pulses), we find the best method, PT-J-HMQC with QFS (Quadruple Frequency Sweep), which is more robust to samples with different sites with different CQ value.(2) the new data processing methods for homonuclear experiments. We combine covariance (COV2D) spectroscopy with non-uniform continuous acquisition (NUCA) scheme, such as linear profile (Lk) and Gaussian profile (Gk). Furthermore, we add various sampling schemes, such as NUS (non-uniform sampling) and CUO (t1 cut-off). We find that covariance treatment, combined with the CUO sampling and Gaussian accumulation profile provides better gain in experimental time, better S/N, without loss of resolution
Ziarelli, Fabio. "Applications et développements des méthodes de résonance magnetique nucléaire haute résolution à l'état solide pour les matériaux organiques et inorganiques." Aix-Marseille 1, 2004. http://www.theses.fr/2004AIX11004.
Gautier, Romain. "Étude structurale de catalyseurs industriels de type phosphates de vanadium : une approche combinant diffraction des rayons X, RMN du solide et calculs DFT." Rennes 1, 2010. http://www.theses.fr/2010REN1S223.
Vanadium phosphates are industrial catalysts used for the conversion of butane into maleic anhydride. However, the mechanisms are not clearly understood due to a poor structural description. An approach combining X-ray diffraction, DFT calculations and solid-state NMR was used in order to have a better understanding of the structural relationships between the different VOPO₄ polymorphs present during the catalysis process. Powder and single-crystal X-ray diffraction combined with solid-state NMR allow to have a better description of VOPO₄ structures. Information about mono- and bidimensional disorders were obtained by DFT calculations. Solid-state NMR experiments showed the presence of low frequency dynamic at the catalytic temperatures. These different observations allowed us to propose a catalytic mechanism in which the shift of V=O bonds into the chains of VO₆ octahedra would be responsible of the catalytic activity. Stacking faults were also studied for lamellar polymorphs. DFT calculations were used as preliminary step for the determination of layers translations. These different approaches allowed describing the intercalation of cations into lamellar vanadium phosphates
Autret, Gwennhael. "Développement de méthodes de spectroscopie RMN localisée 1D filtrée (exposant 1) H (-exposant 13) C double voxel : Application à l’exploration d’une pathologie cérébrale focale chez le petit animal." Evry-Val d'Essonne, 2004. http://www.theses.fr/2004EVRY0026.
We developed a Magnetic Resonance Spectroscopy method for local dynamic investigations of the rat brain metabolism, based on the monitoring of carbon 13 labelled metabolites. For such investigations, we developed and optimized one dimension (1D) localized MRS 1H(-13C) filtered sequences combined with Hadamard encoding. The efficiency of the sequences was tested with the different system of 1H/13C coils we built. The best association of coil device and sequence was applied to the investigation of a focal cerebral injury resulting of the intracerebral administration of an excitotoxic compound, the quinolinic acid. This spectroscopic study was associated to diffusion and T2 weighted imaging studying in order to monitor the evolution of the volume of the injured area in the same
Giovine, Raynald. "Utilisation de méthodes avancées en RMN des solides pour la caractérisation de matériaux de type Metal-Organic Framework : étude de transformations structurales et des effets de la vapeur d’eau." Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1R045/document.
Metal-Organic Frameworks (MOF) are hybrids porous crystalline materials of high interest due to their interesting properties. However, their use in industrial processes is rather low when compared to other porous materials and can be explained by the lower thermal and chemical stabilities of MOF. Such structural modifications can be probed by different technics such as powder X ray diffraction, porosity measurement or Nuclear Magnetic Resonance. In this thesis, advanced solid-state NMR experiments were used (MQMAS, D HMQC and SFAM RESPDOR) to characterized these transformations. These experiments were used to highlight scandium coordination changes e.g. in MIL-100(Sc) (supported by ab-initio calculation of NMR parameters) or to measure variations of internuclear distances (MIL-100(Sc) and MIL 53(Al)). Trapped terephthalic acid were localized by these measurements in MIL 53(Al). Breathing effect of MIL 53(Al) and the dynamic of trapped xenon gas were investigated by 129Xe NMR as a function of temperature (1H→129Xe CPMAS, EXSY and selective inversion recovery). The evaluation of MOF stability when exposed to steam was initiated in this thesis with HKUST 1 Decomposition products formed by hydrolysis were identified by NMR and the stability of HKUST 1 treated under steam flow at 200 °C opens news outlooks for these materials. Besides these studies of structural transformations within MOF, the development of two new NMR experiments was done on: PRESTO-III and D R INEPT sequences. The D-R-INEPT sequence appears to be the most promising scheme especially for DNP-NMR application
Augustyniak, Rafal. "Etude de la protéine partiellement désordonnée Engrailed 2 par RMN et nouvelles méthodes pour la mesure de coefficients de diffusion et l'attribution des signaux des chaines latérales de protéine." Paris 6, 2011. http://www.theses.fr/2011PA066436.
Roussel, Tangi. "Développements de méthodes de traitement et d’acquisition du signal pour la Spectroscopie de Résonance Magnétique 2D in vivo." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10114/document.
In vivo proton Magnetic Resonance Spectroscopy (MRS) is a powerful tool for metabolicprofiling because this technique is non-invasive and quantitative. However,conventional localized spectroscopy presents important in vivo metabolic informationthrough overlapped spectral signatures greatly affecting the quantification accuracy.Two-dimensional (2D) MRS, originally developed for analytical chemistry,has great potential to unambiguously distinguish metabolites. Therefore, metabolitequantification is improved allowing accurate estimation of their concentrations. Inthis thesis, the research findings are presented under two main headings. The firstline of research focuses on conventional 2D MRS J-resolved. A J-PRESS sequencewas developed allowing the acquisition of in vivo 2D MRS spectra, which were processedby a dedicated quantification method. Experiments were performed on therat brain using a 7 T imaging system and different sampling strategies were evaluated.The quantification method, specifically developed to handle 2D J-resolved MRSdata quantification in time domain, is based on a strong prior-knowledge. However,2D MRS suffers from long acquisition times due to the collection of numerous incrementsin the indirect dimension. Therefore, the second line of research focuseson the reduction of acquisition time using recently developed methods based on theultrafast NMR concept. A new pulse sequence was designed, allowing 3D localizedultrafast 2D J-resolved spectroscopic acquisition on a 7T small animal imaging system. This breakthrough allows the acquisition of a complete 2D spectrum in a singlescan, resulting in acquisition times of a few seconds
Devoulon, Philippe. "Méthodes physiques en imagerie de résonance magnétique nucléaire : sélection de coupe, imagerie de diffusion." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10023.
Boucher, Marie. "Estimation des propriétés hydrodynamiques des aquifères par Résonance Magnétique des Protonsdans différents contextes géologiques,de l'échantillon à l'échelle hydrogéologique." Phd thesis, Université d'Orléans, 2007. http://tel.archives-ouvertes.fr/tel-00178045.
Des études expérimentales incluant des mesures géophysiques, des mesures sur échantillon et des essais de pompage ont été menées sur quatre sites représentant un panel varié de contextes hydrogéologiques. Parallèlement, des modélisations numériques ont permis de tester la sensibilité de la méthode RMP à différents paramètres.
Ainsi, la précision d'estimation du toit de nappe dépend de sa profondeur et des propriétés de la zone non saturée. Pour les milieux hétérogènes, une nouvelle méthodologie d'acquisition et d'interprétation 2D/3D des sondages RMP a été développée et validée sur un conduit karstique.
Les mesures sur échantillon montrent que la teneur en eau mesurée par RMP a tendance à être sous-estimée par rapport à celle mesurée par RMN ou par des méthodes classiques. La quantité d'eau manquée dépend de la susceptibilité magnétique de la roche. Souvent, la teneur en eau RMP correspond approximativement à la porosité cinématique, mais une relation quantitative entre ces deux paramètres reste à trouver. La précision sur la teneur en eau RMP peut être améliorée par la prise en compte dans l'interprétation de données géologiques et géophysiques.
Les transmissivités estimées par RMP donnent des valeurs et des incertitudes similaires à celles obtenues par essai de pompage, et sont utilisables quantitativement dans une modélisation hydrodynamique.
Brillouet, Jean-Marc. "Purification et étude des propriétés d'endo-(1->4)-[bêta]-D-xylanases de Polyporus tulipiferae et de l'[alpha]-L-Arabinofuranosidase de Dichomitus squalens : application à l'analyse structurale d'un hétéroxylane ramifié du péricarpe du grain de blé : comparaison avec les méthodes chimiques et physique (RMN)." Grenoble 1, 1986. http://www.theses.fr/1986GRE10054.
Coutouly, Marie-Aude. "Développement d'une méthode d'interprétation rapide des spectres RMN pour les protéines." Université Louis Pasteur (Strasbourg) (1971-2008), 2005. https://publication-theses.unistra.fr/public/theses_doctorat/2005/COUTOULY_Marie-Aude_2005.pdf.
Establishing the correspondence between observed NMR signals and the nuclei in the covalent structure of a protein is termed assignment. This procedure is obligatory for the interpretation of NMR spectra in atom-specific terms, not only when one wishes to determine the structure of a protein but also when a structure is available and one wishes to pursue further studies of the biological system. QUASI (QUick Access to Spectral Interpretation) is software that has been developed to assist assignment. This new tool is able, via its graphical interface, to present results obtained using different user-determined references. Results obtained on proteins of varying sizes, such as α-actinin EF34 (75 amino acids) and the 24 kDa fragment of DNA-gyrase B subunit (220 amino acids), are accurate and reliable. Following assignment, the dynamics of the 24 kDa fragment of DNA-gyrase B subunit were investigated in the presence and absence of ligand inhibitors and as a function of temperature. The residues of the fragment undergo motions on a range of different time-scales from pico- to nano-second, up to milli- to micro-second. The loops that open and close over the active site pocket present particulary complex motions that proved difficult to analyse
Bruguière, Antoine. "Mise au point d’une méthode d’analyse déréplicative par RMN du carbone 13." Thesis, Angers, 2019. http://www.theses.fr/2019ANGE0085.
Extraction and isolation of natural products can be a tedious and time-consuming work and can unfortunately lead to molecules presenting little to no interest. That is why dereplication methods have been developed : they allow the identification of molecules within a mixture, without having to separate them, by comparing their signals to those of references, gathered in databases. In this work, we try to focus on polycyclic polyprenylated acylphloroglucinols (PPAPs), molecules that could be used a therapeutic tool to understand mechanisms involved in immune and inflammatory responses. We first were able to conclude that building databases using predicted values, instead of experimental ones, gave quality results for a dereplication work. Predicted databases were thus used for the rest of the experiments. After taking a look at the different kind of published dereplication methods, we decided to develop our own program based on 13C-NMR, in order to make it more discriminating than the current methods. To do so, in addition to 13C data, DEPT (135 and 90) information were added, allowing to narrow the search by carbon type. A graphic user interface was also implemented, making the program easier to use, but also providing the user with the possibility to interact with the results. This new method was first successfully tested on a diverse range of natural products mixtures, allowing the validation of the method. In the end, the method was used on Garcinia bancana extracts, and made possible the quick identification of the PPAPs we were interested in. Molecules were purified for further biological testing
Maron, Sébastien. "Détermination de faibles quantités de terres rares dans une matrice inorganique par une méthode de RMN." Palaiseau, Ecole polytechnique, 2015. https://theses.hal.science/tel-01180438/document.
Determine the doping level is essential to optimize the properties of materials, e. G. Luminescence. We present an original high-accuracy method based on the 31P solid-state NMR relaxation to determine low concentrations (< 1 %) of paramagnetic lanthanide ions. Our method was first applied to a model compound, LaPO4, within the incorporation of the dopant is known. NMR experiments under static and MAS (15 kHz) conditions reveal that the 31P relaxation time T1 is strongly affected by the presence of paramagnetic ions in the vicinity of the phosphorous nuclei. A linear variation of 1 / T1 as a function of neodymium (Nd3+) or gadolinium (Gd3+) concentration is shown in the 0-10 at. % range for a homogeneous distribution of the doping ions in the matrix. In the case of a solid-state synthesis at 1450 °C, relaxation measurements show that the homogeneous distribution of doping ions is ensured when the mixing of oxide precursors is performed mechanically, in contrast with the manual grinding. The electronic relaxation times of Gd3+ and Nd3+ have been evaluated by ESR measurements under saturation conditions. This allows us to provide a semi-quantitative interpretation of the nuclear 31P relaxation measurements both in Nd and Gd doped LaPO4. In addition, the comparison between nuclear and electronic relaxation suggests that Nd-Gd codoping may improve the efficiency of Gd3+ ions, interesting for the development of relaxing agents in MRI techniques. In a last part, we generalize our method to crystalline or amorphous materials
Maffei, Pablo Fabian. "Développements en microscopie RMN par gradients de champ radiofréquence." Nancy 1, 1993. http://www.theses.fr/1993NAN10017.
Joudieh, Nabil. "Théorie SCF-GIAO-NDDO du diamagnétisme moléculaire et modélisation des susceptibilités diamagnétiques moyennes et des déplacements chimiques de RMN dans le cadre de MOPAC." Rouen, 1998. http://www.theses.fr/1998ROUES065.
Sapay, Nicolas. "Les peptides d'ancrage à l'interface membranaire : analyses structurales par RMN et dynamique moléculaire et développement d'une méthode de prédiction bioinformatique." Lyon 1, 2006. http://www.theses.fr/2006LYO10003.