Rozprawy doktorskie na temat „Imagerie ionique par spectrométrie de masse”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Imagerie ionique par spectrométrie de masse”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
Mériaux, Céline. "Imagerie du système nerveux central par spectrométrie de masse MALDI". Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10059/document.
Pełny tekst źródłaIn recent years, MALDI mass spectrometric imaging has proved to be a powerful tool for biomarker research. This technology allows the analysis of a wide range of endogenous and exogenous compounds in tissue sections. Many developments need to be undertaken to improve the detection of molecules. The sample preparation, including chemical treatment and deposition of the matrix, is dependent on the tissue and molecules of interest and influences the quality of spectra and images. In addition, the bioinformatics tools such as multivariate analysis provide informations on the markers according to phenotypes. These steps are crucial for imaging applications in the field of biology. First of all, we focused on the development of new matrices suitable for MALDI imaging such as ionic matrices. Secondly, these developments have been applied to the invertebrate model, the medicinal leech, at embryonic and adult stages, to compare the biological mechanisms involved in the establishment of the central nervous system and nerve regeneration after injury of this system. Finally, studies of neurological damage have been undertaken to understand the key factors involved in the balance regeneration/degeneration. Thus, studies of human hippocampi samples have revealed the existence of proteins associated with a particular distribution corresponding to layers of neurons abnormally present in the hippocampus of epileptic patients
Arribard, Yann. "Analyse de matière extraterrestre primitive par imagerie hyperspectrale infrarouge et spectrométrie de masse TOF-SIMS". Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASP005.
Pełny tekst źródłaSo-called primitive extraterrestrial matter is characterized by its low chemical evolution since its formation. It is found in particular as one of the constituents of the fragments of small bodies of the Solar system, such as asteroids. The study of samples from these bodies can thus make it possible to better understand its origin and its evolution.In this thesis, my work focused on the analysis of primitive matter and more particularly on the study of carbonaceous chondrites having undergone aqueous alteration. The first part of my thesis focuses on the analysis of mineral and organic phases within petrological type 2 CM chondrites using infrared and Raman spectroscopy techniques as well as time-of-flight secondary ionization mass spectrometry. (TOF-SIMS). These techniques benefit from a good complementarity in the characterization of the different phases that interest us. They are also coupled with imagery, which makes it possible to study the link that may exist between the different mineral and organic phases. I used a new unsupervised process for analyzing infrared hyperspectral data, which made it possible to determine spectral parameters characterizing the state of progress of the aqueous alteration of the samples, in particular of their mineral phase, while relating to their chemical evolution. Raman spectroscopy made it possible to highlight differences in the structure of the polyaromatic organic matter within the different samples. Finally, the TOF-SIMS also highlighted a difference in the structure of the organic matter while confirming and clarifying the differences in co-localization between organic matter and mineral phase observed by hyperspectral imaging between the samples.The second part of my thesis focused on the study of the effectiveness of a new linear accelerator - Andromeda (IJCLab) - as a primary source for TOF-SIMS on analogues of primitive chondrite matter. I produced these organic analogues in the laboratory to simulate insoluble organic matter, the majority of organic matter in chondrites. I checked the characteristics of these analogues by infrared spectroscopy, X-ray spectroscopy and TOF-SIMS. They remain different from CM organic matter in terms of poly-aromatic structure, but similar in terms of elemental composition and insoluble character. I have produced mineral analogues from earth rocks similar to minerals found in CM chondrite. The measurements that I carried out on these analogues and on chondrites show both the potential and the current limits of TOF-SIMS coupled to Andromede, and suggest areas for improvement with a view to increasing, in particular, the masse resolution
Pariot, Christine. "Implication des ions inorganiques dans la différenciation des fibres chez le lin : approche par microscopie ionique analytique". Rouen, 1994. http://www.theses.fr/1994ROUES021.
Pełny tekst źródłaNoun, Manale. "Interaction agrégats-surface. Spectrométrie de masse par temps de vol et application analytique à des études sur des médicaments et sur la météorite Paris". Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00906791.
Pełny tekst źródłaVanbellingen, Quentin. "Imagerie de substances naturelles par spectrométrie de masse". Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS172/document.
Pełny tekst źródłaThis thesis was devoted to the improvement of mass spectrometry imaging methods, and to their use for in situ analysis of natural substances. The first part of this thesis has been dedicated to the development of a new acquisition mode in TOF-SIMS imaging able to acquire images with a high spatial resolution of 400 nm while keeping a good mass resolution. For that, a delayed extraction of the secondary ions has been characterized and optimized. Then, a second part has been dedicated to the study of heartwood production in a tropical species named Dicorynia guianensis. This species is one of the most exploited in French Guiana for its heartwood which exhibits a good durability. Metabolic changes are shown by sub-micrometric resolution ion images recorded in and around the transition zone, where the heartwood formation occurs. Then, TOF-SIMS and MALDI-TOF have both been used to analyse the surface of a bacterial competition. Species have been isolated from a Japanese conifer (Cephalotaxus harringtonia), from which the stains are an endophitic fungi (Paraconiothyrium variabile) and a pathogenic bacteria of the conifer (Bacillus subtilis). The results have shown that the fungus is able to hydrolyze surfactines produced by the bacteria during the competition. Furthermore, both the MALDI-TOF and the TOF-SIMS mass spectrometry imaging are methods of choice to study in vitro models of what could happen in vivo
Domalain, Virginie. "Différenciation de stéréoisomères par couplage, spectrométrie de masse et spectrométrie de mobilité ionique". Rouen, 2014. http://www.theses.fr/2014ROUES023.
Pełny tekst źródłaThis PhD work deals with analysis of stereoisomers, which present very close collision cross section difference (DeltaCCS ≤ Å2), by the coupling of ion mobility spectrometry and mass spectrometry (IM-MS). A study of diastereoisomers M which are functionalized entities found in a lot of natural products, rise to an efficient strategy based on cationisation (with alkali cations X and transition metals (X)II) and formation of multimers [3M+X]+ and [3M+(X)II-H]+ allowing the differentiation and the separation of stereoisomers, particularly enantiomers of amino acids and diastereomers with a major biological interest. It has been highlighted that the cationisation allows a significant increase of the stereoisomers differenciation. Then, we have shown that the nature of asymmetric center substituents plays an important role on the ion mobility separation
Jeanne, dit Fouque Kevin. "Différenciation de topoisomères peptidiques par spectrométrie de masse à mobilité ionique et spectrométrie de masse en tandem". Rouen, 2016. http://www.theses.fr/2016ROUES020.
Pełny tekst źródłaLasso peptides are ribosomally synthesized and post-translationnally modified peptides produced by bacteria, sharing a mechanically interlocked topology that is essential for their biological activity. This PhD work focused on the structural characterization of lasso peptides and differentiation between their branched-cyclic topoisomers using ion mobility – mass spectrometry (IM-MS) and tandem mass spectrometry (MS/MS). IM-MS studies led to the development of a method based on the use of a supercharging reagent, highlighting an additional charge state of multiply protonated species, for which the lasso and branched-cyclic topologies were clearly differentiated and separated in mixture. To assess the developed method, this strategy was also applied to other types of constrained (macrocyclic, disulfide bonds) and unconstrained (linear) structures. IRMPD spectroscopy studies allowed to characterize the changes in the hydrogen bond network, associated with the unfolding of the gas phase conformation, as a function of the charge state of multiply protonated species. The spectroscopic data could thus be correlated with the ion mobility data. IM-MS provides an overview of the conformation through a collision cross section measure (CCS), while IRMPD spectroscopy allows to probe intramolecular interactions through the hydrogen bonds. The structural characterization of lasso and branched-cyclic peptides was also carried out using MS/MS of triply protonated species. These experiments enabled us to establish general rules of fragmentation evidencing lasso topologies in collision induced dissociation (CID) and electron transfer dissociation (ETD)
Maire, Florian. "Étude des dendrimères polyamidoamines par spectrométrie de masse et mobilité ionique". Rouen, 2010. http://www.theses.fr/2010ROUES018.
Pełny tekst źródłaIn the first part of this work, we report the formation of unexpected ions during mass spectrometry analysis of a first-generation polyamidoamine dendrimer using an electrospray ionization source in negative ion mode. The study of these ions, corresponded to an increase of 12 Da, showed that an electrical discharge in the electrospray source was the origin of these artefacts. In the second part, we use ion mobility coupled with mass spectrometry as an analytical technique to determine the size of polyamidoamine dendrimers up to generation 3. Our results showed a good agreement with those obtained by molecular models and literature values. Furthermore, polyamidoamine dendrimer isobaric ions were dispersed by the combination of ion mobility and mass spectrometry. The third part deals with the study of non-covalent complexes involving first-generation polyamidoamine dendrimer and single stranded oligonucleotides. MS/MS fragmentation of these complexes was different according to the charge state of the complex and the oligonucleotide length. Relevant information, concerning complex stability in the gas phase, was obtained only for larger non-covalent complexes
Seyer, Alexandre. "Imagerie par spectrométrie de masse : développements méthodologiques et applications biologiques". Thesis, Evry-Val d'Essonne, 2010. http://www.theses.fr/2010EVRY0028/document.
Pełny tekst źródłaMy PhD’s work consisted in continuing the development of Mass Spectrometry Imaging (MSI) methods, in terms of methodology improvements but also through biological applications.The first part concerned the development of a novel sample preparation method dedicated to very small objects for chemical imaging, particularly for TOF-SIMS imaging. This method has been validated by studying different types of flavonoids in from seeds of Arabidopsis thaliana, with a size of 400 nm only. The second part, dedicated to biological applications, is divided into two sections. The first section includes two projects where the goals was to detect and locate, using TOF-SIMS imaging, the active molecule of an anti-acne cream in human skin sections, and a brominated flame retardant, the decabromodiphenyl ether, in target tissues in rats. In the second section, we have studied by MALDI-TOF and TOF-SIMS imaging the lipid absorption during the digestion, and finally, with the help of statistical analysis tools, we compared lipid profiles of healthy samples versus those from cystic fibrosis samples in a model animal of the disease.Through these projects, we have concluded that MALDI-TOF and TOF-SIMS imaging are two complementary techniques, and, when they are combined with statistical analysis, they can be powerful tools
Debois, Delphine. "Imagerie moléculaire d'échantillons biologiques par spectrométrie de masse ToF-SIMS". Thesis, Evry-Val d'Essonne, 2008. http://www.theses.fr/2008EVRY0014/document.
Pełny tekst źródłaMy PhD’s work has been devoted to the development of the emergent technique ToF-SIMS imaging. The first part of my work was dedicated to fondamental aspects with the use of a fullerene ion source as a primary ion beam or sputtering ion beam. We expected to realize 3D imaging. The second part of my work consisted to applications of the mass spectrometry imaging. Several application fields were studied, as archeology as with the analysis of patina of the Dogon statuary or chinese mummy hair. A third project was dedicated to the in situ biomarker research from human liver biopsies. The goal of this study was to identify a potential lipid biomarker of the non-alcoholic fatty liver disease. The last part of this manuscript is devoted to the in situ qualitative and quantitative analysis of surfactins (a family of heptacyclodepsipeptides) on a Bacillus subtilis swarming community. We combined ToF-SIMS imaging for qualitative analysis and localization of surfactins within the swarming pattern and MALDI-TOF mass spectrometry for the quantification of these species. The results ot this PhD’s work show that ToF-SIMS imaging could be applied to various fields of research as archeology, microbiology and medicine
Touboul, David. "Imagerie biologique par spectrométrie de masse. Aspect fondamentaux, méthodologies et applications". Evry-Val d'Essonne, 2006. http://www.theses.fr/2006EVRY0010.
Pełny tekst źródłaMy PhD’s work has been completely devoted to develop new imaging mass spectrometry (IMS) techniques, called MALDI-TOF imaging and cluster-TOF-SIMS imaging. The first part of this manuscript was dedicated to instrumental developments. For MALDI-TOF imaging, the goals were to optimize the matrix deposition and to develop methods for identifying biomarkers. For TOF-SIMS imaging, the objectives were to test new cluster ion sources and to perfect structural analysis. Complementarities between these two innovative imaging techniques were also demonstrated. The second part was devoted to biological applications (Duchenne Muscular Dystrophy, Fabry Disease, saponine effects on human melanoma cells) or to surface analysis (archaeological samples and OPLC-IMS). The results of this PhD work enlightened the fact that MALDI-TOF and cluster-TOF-SIMS imaging methods are new powerful tools to study drug distribution and to find new biomarkers in biological tissues
Courrier, Benoît. "Caractérisation par spectrométrie de masse des molécules neutres induites par ablation laser". Metz, 2000. http://www.theses.fr/2000METZ057S.
Pełny tekst źródłaIdentification of neutral molecules emitted during laser materials interaction is one of the research axes developed by the Laboratoire de Spectrométrie de masse et chimie laser (LSMCL). Characterization of neutral molecules emitted during laser ablation was achived by developing a laser ablation/quadripolar mass spectrometer coupling system via gazeous chromatrography (GC/MS). The laser pyrolisis results were compared firstly those obtained by thermal pyrolisis GC/MS. They showed the strong dependance of power, the formation of aggregates and the mecanisms of decarboxylation for organic acids used as MALDI matrix. Due the introduction mode of neutral species into the chromatographic column, they was a weak sensitivity more especially for low density. The purpose of our studies was to develop and to carry out a device for identification of the neutral molecules emitted during laser ablation by increasing the detection sensitivity. Gazeous chromatography was removed and we replaced a mass spectrometer. This one is more sensitive than the GC/MS because several ionization modes can be used (electron impact EI and chemical ionization CI). When thesis is devided in two parts : the first one is confidential and will relate the presentation and the development of the device ; the second part is be devoted on the one hand, to the studied of the laser ablation of synthetic polymers and on the other hand, to the laser ablation of organic compounds used as MALDI matrix, in order to identify neutral molecules emitted
Bouvier, Caroline. "Étude du vieillissement de peintures anciennes par imagerie par spectrométrie de masse 3D". Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS008.
Pełny tekst źródłaThe objective of the PhD was to evaluate the potential of TOF-SIMS imaging, particularly 3D, to reliably study chemical composition in stratigraphic sections of ancient paintings. TOF-SIMS imaging can simultaneously map organic and inorganic materials at the micrometer scale, providing answers to questions about ancient paintings, such as elucidating the nature of the binders and pigments in the various layers, or studying the chemical transformations of ingredients through the action of time and interactions. The construction of a database of TOF-SIMS mass spectra for reference materials in parallel with the study of several samples of old paintings, has allowed to identify which reliable chemical information can be associated with the use several centuries ago of a given ingredient according to a certain painting technique. The references and the parameters of the analyses were adapted according to the observations made on the cross sections. The identification of drying oils and egg yolk was considered. Different surface preparations and secondary ion extraction parameters were compared to optimise the detection of surface-formed ionic species and obtain more representative chemical information. The conditions under which argon aggregate sputtering can be used were defined. A preliminary analysis of the contribution of TOF-SIMS imaging to the understanding of the structure of dried drying oils has provided results that will be continued in the future
Wisztorski, Maxence. "Développements en imagerie par spectrométrie de masse et applications aux modèles invertébrés". Lille 1, 2006. https://ori-nuxeo.univ-lille1.fr/nuxeo/site/esupversions/b2cd98ef-2445-48bc-9462-f547716f3776.
Pełny tekst źródłaHupin, Sébastien. "Caractérisation d’auto-assemblages de polyoxométallates hybrides organiques-inorganiques par spectrométrie de mobilité ionique couplée à la spectrométrie de masse". Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR062.
Pełny tekst źródłaPolyoxometalates (POM) are anionic compounds formed by the assembly of metal oxide polyhedra {MOy}, (with M, MoVI or WVI) linked together by oxygen atoms. POM thus form a remarkable class of nanometric inorganic metal oxide clusters, with a wide variety of charges and structures. It is possible to form hybrid systems including the inorganic part of the POM and a grafted organic part, allowing new functionalities to be added to the POM, such as selfassembly. We have dedicated this thesis work to the characterization of standards, hybrid and self-assembled POM systems by mass spectrometry coupled to ion mobility spectrometry (IMS-MS). A first experimental approach using drift tube ion mobility spectrometry (DTIMS) allowed us to determine the collision cross sections (CCS) of standard POM in helium and nitrogen. The CCS of the POM standards then allowed us to calibrate an IMS cell of a Travelling Wave ion mobility instrument (TWIMS). The analysis by IMS-MS of organic-inorganic hybrid POMs alone or in the presence of transition metal cations revealed the presence of self-assembled triangular [POM3·cation3], square [POM4·cation4] or pentagonal [POM5·cation5] systems with different charge states. CCS values of these self-assemblies was estimated from the calibration of the TWIMS cell. Using a theoretical approach, we modelled several standard POM structures with and without tetrabutylammonium counterion (TBA+) using density functional theory (DFT). The optimized structures were used to determine theoretical CCS using the trajectory method of the MOBCAL software, in which we incorporated molybdenum and tungsten atoms for which we optimized new Lennard Jones potential parameters. The correspondence of experimental and theoretical CCS of standard POM structures offers new possibilities for structural attribution of self-assembled hybrid POM by coordination in the presence of metal cations
Fournier, I. "Développements en Imagerie par Spectrométrie de Masse MALDI et Applications aux Problématiques Biologiques". Habilitation à diriger des recherches, Université des Sciences et Technologie de Lille - Lille I, 2005. http://tel.archives-ouvertes.fr/tel-00167305.
Pełny tekst źródłaCependant, afin d'augmenter encore la potentialité de cette technologie, des développements restent encore à effectuer. Les recherches menées ont donc plus particulièrement portées sur ces développements.
En particulier, la recherche et l'étude de nouvelles matrices plus adaptées à l'analyse directe de tissu en MALDI sont particulièrement importantes. Dans ce contexte, certaines matrices ioniques se sont révélées particulièrement adaptées aux tissus en permettant d'obtenir une plus grande intensité du signal, un plus grand nombre de composés détectés, de bonnes performances en mode négatif, une grande homogénéité de cristallisation, une grande stabilité sous vide et une faible ablation de matériel consécutivement à l'irradiation laser. Dans un autre aspect, le traitement préalable des tissus permet également une amélioration de la qualité spectrale et des performances d'études structurales en mode MS/MS. Se sont révélés particulièrement intéressants les traitements des tissus aux solvants organiques et les digestions enzymatiques et en particulier pour les tissus conservés en blocs de paraffine après fixation.
D'autre part l'étude de la répartition des ARNm au sein des tissus est un développement crucial afin d'obtenir des images de colocalisation transcriptome/protéome. Est proposé dans ce travail un nouveau concept permettant de réaliser ces images, basé sur une analyse indirecte des ARNm, au travers de l'utilisation d'un groupement photoclivable relié à un peptide marqueur de séquence connue qui sera détecté.
Enfin, l'ensemble de ces développements trouve de nombreuses applications dans le domaine de la biologie et notamment dans le cadre de pathologies tel que le cancer de l'ovaire.
Dadi, Hala. "Analyse par spectrométrie de masse des tubulines et de l'hormone de croissance". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS582.
Pełny tekst źródłaThe tubulins are proteins involved in cellular processes that are essential for cell life. The tubulins are polymodified at their C-terminal extremities. Different techniques have been used to characterize the polymodifications of tubulins. However, some challenges remain in the fine identification of some structures. In fact, mass spectrometry ion mobility can separate ions of the same m/z ratio depending on their conformations. In the first part of this thesis, an ion mobility mass spectrometry analysis allowed the separation of two synthetic peptides that mimic the structure of C-terminal peptides of biglycylated α-tubulins. In order to extrapolate this type of experiment to the C-terminal peptides purified from biological tubulins, we employed an analytical process to analyze these peptides from purified brain tubulins. Growth hormone (GH) is an anabolic hormone and a doping agent used by athletes. The availability of rhGH in the black-market has continuously increased because of doping in sports. The natural and the biosynthetic hGH have identical peptidic sequences. So far, the valid hGH anti-doping tests by the world antidoping agency are based on immunological recognition. However, Immunoassays have their own limitations. Therefore, the next generation analysis of GH has to be more specific and accurate. In the second part of this thesis, mass spectrometry coupled to reversed phase chromatography was used to find chemical differences between the pituitary hGH and the rhGH. The pituitary extracted hGH is glycosylated whereas the biotech product is sugar free. The present work represents an opening towards a novel methodology for a novel hGH anti-doping test
Albrieux, Florian. "Etude conformationnelle de peptides et protéines par mesure de mobilité ionique couplée à la spectrométrie de masse". Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00594601.
Pełny tekst źródłaPoyer, Salomé. "Développement de méthodes d'analyse par spectrométrie de masse à mobilité ionique pour l'identification des analogues de saxitoxine". Rouen, 2015. http://www.theses.fr/2015ROUES053.
Pełny tekst źródłaThis thesis work focused on the separation and identification of saxitoxin analogues, natural neurotoxic compounds. Modern separation techniques such as hydrophilic interaction liquid chromatography (HILIC) and ion mobility spectrometry (IMS) coupled to mass spectrometry (MS) were developed for the analysis of saxitoxins. HILIC-MS and IMS-MS coupling were developed, showing a complementary for separation of the various saxitoxin analogues. HILIC-IMS-MS coupling was then optimized and allowed the fast separation of the toxin analogues. The HILIC-IMS-MS coupling was also repeatable when complex mixtures were injected, although it was less sensitive than with the coupling of HILIC with a triple quadrupole instrument operated in targeted mode. IMS application to saxitoxins also permitted to determinate the collision cross section values of each analogue. The calculation of theoretical structures permitted the determination of theoretical collision cross sections that were correlated to experimental values and allowed the access of gaseous phase conformation. Saxitoxin analogues characterization was carried out by tandem mass spectrometry of [M+H]+, [M+Li]+, [M+Na]+, [M+K]+ and [M−H]− species. The different product ions gave information about stability of chemical functions depending on the different species studied
Piednoël, Hélène. "Recherche de marqueurs biologiques de la dystrophie musculaire de Duchenne par spectrométrie de masse et imagerie MALDI-TOF". Evry-Val d'Essonne, 2005. http://www.theses.fr/2005EVRY0005.
Pełny tekst źródłaThe aim of this work is the study of Duchenne muscular dystrophy (DMD) markers by MALDI-TOF mass spectrometry (MS and MS/MS). After a description of experimental and of the study issue of this work, results relative to this study, linked to a muscle weakness and associated to a defect of the lipid metabolism. In the same way as over-expression of two proteins implicated, either in muscular degradation mechanisms, or in calcic homeostasis. The study of the fatty acids composition of glycerophosphatidylcholines by MALDI-TOF Mass Spectrometry MS and MS/MS enabled us to characterize a change of the lipid composition of dystrophic cells at the time of the differentiation. This modification has been used as a marker to identify with profiling and imaging MALDI-TOF-MS regenerating areas in sections of a mdx mouse leg muscle. It is the first time that such a slight change in fatty acids composition is observed directly on tissue slices by Mass Spectrometry. This approach can be usefull in monitoring the treatment of the DMD
Gut, Yoann. "Imagerie par spectrométrie de masse MALDI et outils chimiométriques pour la cartographie de formes pharmaceutiques solides". Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2012.
Pełny tekst źródłaEuropean Medicines Agency (EMA) recommendations stipulate that pharmaceutical companies have to continually improve manufacturing efficiency to ensure drug product quality. The commonly used analytical tools provide information about drug substance quality and dosage or the drug release profile by dissolving the whole tablet. However these analytical tools are not able to highlight the distribution of chemical compounds contained in the tablet. This is why chemical imaging such as MALDI MSI are used to extract the spatial and spectral information from pharmaceutical solid dosage forms. This hyperspectral imaging technique needs complex sample preparation and generates huge dataset. These two features, as well as the lack of optimized mass spectrometers to study tablets, make difficult the implementation of the MALDI MSI in industrial laboratories. During this thesis, the sample preparation protocol has been improved, the mass spectrometer has been optimized to analyze tablets and chemometrics tools has been developed in order to implement MALDI MSI within Technologie Servier company
Kernalléguen, Angéline. "Caractérisation et localisation des xénobiotiques dans les cheveux par spectrométrie de masse Maldi". Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0754.
Pełny tekst źródłaHair analysis is now recognized as a relevant tool in the field of toxicology. It provides a precise history of an individual’s exposure to drugs, whether it is a punctual or repeated consumption.Matrix-Assisted Laser Desorption/Ionization (MALDI) has many advantages over conventional techniques: the amount of hair needed is reduced, the sample preparation is simplified and the images are acquired with high spatial resolution (~ 100 μm).MALDI (MALDI-MSn) imaging allowed us to characterize and map the evolution of drugs amounts along the hair with very spatial resolution avoiding long and complex pre-sample preparation.MALDI coupled to Microaarays for Mass Spectrometry (MAMS) allowed us to develop a method for semi-quantitation of cocaine, benzoylecgonine, ecgonine methyl ester and cocaethylene using 1 mg of hair and 2 hours of extraction; the results are well correlated with a validated quantification method. This method is relevant when urgent results are required.In total, the development of these two applications demonstrates the relevance of MALDI mass spectrometry in the toxicological analysis of hair. The prospects are to improve these protocols in order to transpose them routinely and to develop large screening methods by MALDI mass spectrometry
Ballivian, Renaud. "Étude de complexes non-covalents et de polymères organiques par couplage entre la spectrométrie de masse et la mobilité ionique". Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10219.
Pełny tekst źródłaKnowing the structure of non-covalent complexes is essential to understand many biological processes. The first step is the characterization of the interactions leading to the adoption of a functional tridimensional structure by a multimeric assembly. The second step consists of underlining the structural modifications induced by the complexation, and their influence on the system’s function. The Ion Mobility/Mass Spectrometry (IM/MS) is a gas-phase method that is used to separate ions according to their geometry and their masse-to-charge ratio. IM/MS also provides insights on their intrinsic properties, by measuring their collision cross sections. Using this method, we have studied the structure of three different non-covalent complexes: the aggregation of tannins on the human salivary protein IB-5, the fixation of a small ligand (Ac2KAA) on vancomycin, and the complexation between metallic cations and poly-lactid polymers. The evolution of the collision cross-sections as a function of the size of the system or the complexation state clearly shows structural transitions. Moreover, combined with molecular modeling or laser spectroscopy, the IM/MS technique reveals to be a powerful tool to characterize the relevant interactions in such systems. This work proves that IM/MS, besides a powerful analytical aspect, can also be used in global studies that involve several structural methods to resolve the structure of large multimeric assemblies
Franck, Julien. "Développement des stratégies d’identification en mode bottom-up pour l’imagerie par spectrométrie de masse MALDI". Electronic Thesis or Diss., Lille 1, 2009. http://www.theses.fr/2009LIL10079.
Pełny tekst źródłaSince its introduction in 1997 by the group of R.M. Caprioli, direct tissue analysis and imaging by Mass Spectrometry have now become good complementary methods of classical proteomics techniques. Direct analysis of tissues gives access to the detection of hundreds of biomolecules while maintaining tissue integrity and by automation of this approach, molecular images of biomolecules distribution can be obtained in one step analysis. However, many developments need to be undertaken especially on the improvement of the detection of different classes of biomolecules including lipids, peptides and proteins. Moreover, if the localization of molecules of interest is possible but no structural information can obtained from proteins. If proteins identification can be delicate under classical proteomics conditions this is even truer by working directly on tissues. A bottom-up strategy will allow the identification and localization of proteins after MS/MS experiments of peptides generated after in situ enzymatic digestion. In most of cases, MS/MS is used to check the sequence of an expected endogenous peptide or obtained after digestion but MS/MS but spectra generated from instruments equipped with a MALDI ion source are often complex to analyze because of the different types of fragment series generated during the fragmentation process. This is especially true on MALDI-TOF systems that frequently for which weak fragmentations (especially in the higher m/z range of the MS/MS spectrum) and to very different series of fragment ions creating largely incomplete set of series only giving access to small sequence tags are often observed. Thus, we have studied on tissue N-terminal chemical derivatization of peptides for proteins identification in Bottom-up Imaging strategies. The derivatives promote efficient charge-site initiated cleavage of backbone amide bonds and they enable the selective detection of only a single series of fragment ions. Optimization of reactions were first performed at the whole tissue section scale and then modified and adapted to allow for the derivatization to be automatically performed using a micro-spotting piezoelectric automatic deposition device. Finally, we report a whole sequence of on tissue bottom up strategy followed by automatic derivatization and show that such strategies improve protein assignment and de novo sequencing directly from tissue sections, which is a key point for on tissue direct identification of markers
Marie, Arul. "Études structurales des oligomères fluorés par spectrométrie de masse : mécanisme de désorption et orientation des processus de dissociation". Paris 6, 2002. http://www.theses.fr/2002PA066246.
Pełny tekst źródłaFranck, Julien. "Développement des stratégies d’identification en mode bottom-up pour l’imagerie par spectrométrie de masse MALDI". Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10079/document.
Pełny tekst źródłaSince its introduction in 1997 by the group of R.M. Caprioli, direct tissue analysis and imaging by Mass Spectrometry have now become good complementary methods of classical proteomics techniques. Direct analysis of tissues gives access to the detection of hundreds of biomolecules while maintaining tissue integrity and by automation of this approach, molecular images of biomolecules distribution can be obtained in one step analysis. However, many developments need to be undertaken especially on the improvement of the detection of different classes of biomolecules including lipids, peptides and proteins. Moreover, if the localization of molecules of interest is possible but no structural information can obtained from proteins. If proteins identification can be delicate under classical proteomics conditions this is even truer by working directly on tissues. A bottom-up strategy will allow the identification and localization of proteins after MS/MS experiments of peptides generated after in situ enzymatic digestion. In most of cases, MS/MS is used to check the sequence of an expected endogenous peptide or obtained after digestion but MS/MS but spectra generated from instruments equipped with a MALDI ion source are often complex to analyze because of the different types of fragment series generated during the fragmentation process. This is especially true on MALDI-TOF systems that frequently for which weak fragmentations (especially in the higher m/z range of the MS/MS spectrum) and to very different series of fragment ions creating largely incomplete set of series only giving access to small sequence tags are often observed. Thus, we have studied on tissue N-terminal chemical derivatization of peptides for proteins identification in Bottom-up Imaging strategies. The derivatives promote efficient charge-site initiated cleavage of backbone amide bonds and they enable the selective detection of only a single series of fragment ions. Optimization of reactions were first performed at the whole tissue section scale and then modified and adapted to allow for the derivatization to be automatically performed using a micro-spotting piezoelectric automatic deposition device. Finally, we report a whole sequence of on tissue bottom up strategy followed by automatic derivatization and show that such strategies improve protein assignment and de novo sequencing directly from tissue sections, which is a key point for on tissue direct identification of markers
Sejalon-Cipolla, Mylene. "Profilage de métalloprotéases par spectrométrie de masse MALDI via l’utilisation de nouvelles sondes moléculaires (ABP)". Electronic Thesis or Diss., Montpellier, Ecole nationale supérieure de chimie, 2022. http://www.theses.fr/2022ENCM0015.
Pełny tekst źródłaActivity-based probes bind covalently to their target enzymes in a mechanism-based manner allowing unambiguous discrimination between the active enzyme and its inactive or inhibitor-bound counterparts. Since metalloproteases catalysis is non-covalent, activity-based probes that target them have been developed using reversible inhibitors decorated with photo-crosslinkers, which limit their scope to ex vivo use. By relying on a favorable structural context and by exploiting targeted chemistry, ProMAP project will focus on development of novel activity-based probes capable of covalently modifying matrix metalloproteases without making use of photo-activation. Within human protease family composed of more than 500 members with approximately one third of metalloproteinases, matrix metalloproteases (MMPs) constitutes a small enzyme family of 23 members involved in very many pathophysiological phenomena (cancers, wound healing, inflammation). The role of these zinc-dependent endopeptidases remains to be clarified in numerous biological processes. Some MMPs participate in disease progression while others play a protective function, stressing the need to better document their spatial and temporal activation in various biological contexts. MALDI-MS mass spectrometry is one of the methods of choice to achieve this mapping. Mass spectrometry protein tracking, present in low abundance in a complex environment, represents a real challenge. In this context, chemical derivatization is a very promising technique for improving detection of peptides by mass spectrometry. This approach consists in conjugating a MS-tag to peptides for modifying their ionization properties. MALDI MS-tags enable to discriminate signals induced by labelled peptides from those of unlabeled ones. This discriminating effect represents a method of choice for the detection and quantification of low-abundance peptides in complex proteomes
Le, Faouder Julie. "Recherche de biomarqueurs tissulaires de la cancerogenèse hépatique par imagerie Maldi". Paris 7, 2012. http://www.theses.fr/2012PA077002.
Pełny tekst źródłaHepatocellular carcinoma (HCC) represents the sixth most common cancer in the world, and the third most frequent oncological cause of death. Over 80% of HCC develop from cirrhosis, mainly related to viral etiology. The prognosis of HCC is mostly poor, because of its late detection at an advanced stage. Thus, new effective biomarkers are needed. MALDI imaging mass spectrometry (MALDI IMS) allows differential distribution visualization of potential markers within tissue. The aim of the present project was to investigate, using MALDI IMS, the proteome of HCC and to compare it with peritumoral cirrhosis so as to characterize new biomarkers of HCC. We found a set of proteins/peptides with a differential intensity level that most accurately delineated cancer from adjacent cirrhotic tissue. We generated a classification model enabling correct classification of most spectra present in cirrhosis or tumor areas from the independent validation group. The most discriminating marker (m/z 8,565) increased in HCC was characterized as the monomeric ubiquitin and further validated by immunohistochemistry. Marker m/z 2,753 was a peptidic fragment of albumin and was overexpressed in HCC while m/z 3,195, identified as a fragment of the alpha chain of hemoglobin, was specifically more intense in cirrhosis. This work provides complementary tools that could be useful in the early diagnosis of HCC. Identified biomarkers will gain further insights in the role of proteasome in the liver cancerogenesis. MALDI IMS and identification developed methods will be useful for other projects
Ruch, David. "Étude comparée des matériaux polymériques et/ou polysulfurés par ablation/ionisation laser et bombardement ionique couplés à la spectrométrie de masse : Application à la caractérisation d'élastomères vulcanisés". Metz, 2002. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2002/Ruch.David.SMZ0223.pdf.
Pełny tekst źródłaLemaire, Rémi. "Nouveaux développements pour l'imagerie par spectrométrie de masse MALDI : applications aux problèmes biologiques et à la recherche de biomarqueurs dans le cancer de l'ovaire". Paris 6, 2006. http://www.theses.fr/2006PA066288.
Pełny tekst źródłaBardin, Noémie. "Composition isotopique des éléments légers dans les micrométéorites ultracarbonées par spectrométrie de masse à émission ionique secondaire à haute résolution en masse, contribution à la connaissance des surfaces cométaires". Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS189/document.
Pełny tekst źródłaThis thesis covers the isotopic analysis of carbon-rich interplanetary dust (ultracarbonaceous micrometeorites), in order to better understand the isotopic fractionation process of light elements (hydrogen and nitrogen) observed in the organic phases of primitive extraterrestrial matter. It is possible, within a collection of micrometeorites coming from the central regions of the Antarctic continent, to identify ultra-carbonaceous micrometeorites (UCAMMs – for Ultra-Carbonaceous Antarctic MicroMeteorites) which contain about ten times more carbon than the primitive meteorites. These particles are extremely rare and open the possibility to study in laboratory cometary particles of large sizes (100-200 microns). This thesis focuses on the isotopic analyses of UCAMMs, in order to understand the isotopic fractionation processes of light elements (hydrogen and nitrogen) observed in the organic matter of the primitive solar system. Mineralogical, chemical and structural analyses on two fragments of ultra-carbonaceous micrometeorites were performed in the framework of collaborations using techniques of scanning electron microscopy, electron microprobe, infrared microspectroscopy (SOLEIL synchrotron). The main work of this thesis concerns the isotopic analysis of two UCAMMs by Secondary Ion Mass Spectrometry (SIMS) using the NanoSIMS ion microprobe. The instrumental developments performed in collaboration between the CSNSM and the Curie Institute teams allow to resolve molecular interferences with a mass resolving power higher than 20 000 retaining a sensibility compatible with the measurements considered here. So, it has been possible to measure for the first time the hydrogen isotopic composition with the polyatomic ions 12C2D- and 12C2H- and to compare its spatial distribution with that of the nitrogen (12C15N-/12C14N-) obtained on the same surface with the same magnetic field. A protocol for producing a series of standard samples was developed from polymers isotopically enriched in deuterium in order to determine the instrumental fractionation of the NanoSIMS showing the possibility to perform precise measurements of the hydrogen isotopic composition in the organic matter with polyatomic ions (CD-/CH- and C2D-/C2H- ratios). The isotopic maps at high spatial resolution (200 nm) in C2D/C2H and C15N/C14N show a very heterogeneous distribution in deuterium with extreme values going up to 20 times the terrestrial ocean value, whereas the 15N/14N ratios remain globally close (within 20%) to the terrestrial atmosphere value. Measurements of N/C ratios in ion imaging performed at the NanoSIMS confirm the values measured by electron microprobe and show that the organic matter of UCAMMs is rich in nitrogen. Comparisons between isotopic images with each other and with the images obtained by the other techniques show that the organic matter of ultracarbonaceous micrometeorites is constituted of different components. The main component doesn’t exhibit a correlation between the D and 15N excesses. A minor component of the analyzed surface exhibits correlated excesses in D and in 15N, without neither the elemental or structural composition of this component significantly differs from the rest of the grain. Finally, a minor component showing moderate enrichments in D and 15N/14N ratios lower than the terrestrial atmosphere value could have been identified.All the data can be explained assuming that the ultracarbonaceous micrometeorites come from the surface of transneptunian icy objects. The elemental and isotopic characteristics observed in the organic matter of UCAMMs might result from the mixing of different strata of the parent body having undergone irradiation by the galactic cosmic radiation at large heliocentric distances
El, Ayed Mohamed. "Applications de l’imagerie par spectrométrie de masse MALDI à la recherche de biomarqueurs du cancer de l’ovaire". Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10064/document.
Pełny tekst źródłaAt the proteomics’ time, mass spectrometry has become a powerful tool for research and identification of biomolecules. Over the past decade, a new application, MALDI imaging was grafted to the existing methods for the detection of biomolecules such as peptides, proteins and lipids in tissues. Applied to biomarkers research in ovarian cancer, this technique allowed us to identify several proteins expressed in cancer using differential analysis system based on statistical tools such as principal component analysis (PCA). Among the biomarkers identified, we found a fragment of the 11S immunoproteasome. The location of this fragment in cancer tissue has been validated by IHC; it is present in epithelial cells with a change of localization between cancer and Benin, from the nucleus to the cytoplasm. A list of specific tissue markers for ovarian cancer has been obtained, most of them corresponding to a protein associated with cell proliferation, involved in modulating immune response, signaling at the cytoskeleton, the tumor progression and conversion of epithelial cells with mesenchymal cells. A cross validation was performed by a specific new approach TAG MASS, by Western Blot and PCR (using SKOV3 ovarian cancer cells). The second point is the study of the presence of the protein Reg alpha in the fluids. Subsequently, with the discovery of a large number of biomarkers identified by MS corresponding to proteins cleaved, a hypothesis of a viral etiology has been proposed for further work. Were able to identify oncovirales proteins of herpes viridae family as HHV6, HHV4 and EBV. Finally, we managed to develop new quantification techniques using mass spectrometry technique based on the ELISA and PCR
Allali, Hakim. "Aspects de l'émission ionique secondaire induite dans des couches isolantes inorganiques par des ions argon d'une dizaine de MeV". Lyon 1, 1993. https://tel.archives-ouvertes.fr/tel-00746656.
Pełny tekst źródłaPicot, d'Aligny d'Assignies Gaspard. "Nouvelles techniques non invasives d'étude de la stéatose hépatique par résonance magnétique : implications cliniques". Paris 7, 2014. http://www.theses.fr/2014PA077034.
Pełny tekst źródłaFatty liver affects nearly 20% of the population and its frequency is growing exponentially. This condition located at the crossroads of metabolic syndrome, cardiovascular risk and carcinogenesis has a major impact on public health. The need to develop methods for detecting and quantifying fatty liver is imperious. Liver biopsy is invasive and prone to sampling bias that compromises its clinical use. In this context, Inagnetic resonance (MR) methods are superior to other non- invasive methods such as ultrasonography and CT. MR spectroscopy has become the reference method for liver fat quantification. Because of MR spectroscopy complexity, MR imaging is the preferred method in the clinics and allows for a morphological and regional approach. In a preliminary study we have shown that liver fat can be detected precisely with spectroscopy and MR imaging. Using an image segmentation method (morphometry) at histology to overcome the variability of visual interpretation we have shown an excellent correlation between histology and MR methods in quantifying liver fat. The following studies that form the body of this thesis use the methods of MR quantification to address several clinical questions. First, we have shown that the early onset of steatosis in a glucolipotoxic rat model can be detected. The control rats can be differentiated from treated rats with MR quantification methods, while histology fails to show these subtle differences. The rate of liver fat is correlated with biomarkers of insulin resistance. At MR imaging, we have developed an algorithm for semi- automatic segmentation that allows analyzing during the same examination the hepatic volume and the total liver fat content. We show that while there is a macroscopic heterogeneity of fat distribution, it does not have a systematic segmentai distribution. Finally, we have shown that the presence of hepatic steatosis > 5% , detected by routine MR imaging , is associated with a significant increase in postoperative complications and time of hospitalization alter major hepatectomy. Ln conclusion, MRI imaging can reliably quantify hepatic steatosis and is thus a major tool for assessing the causes and consequences of fatty liver disease. It also paves the way for therapeutic interventions by permitting objective screening and monitoring
Thiery, Gwendoline. "Imagerie par désorption laser/spectrométrie de masse de multiples marqueurs spécifiques : développement de la technique TAMSIM "Targeted Multiplex Mass Spectrometry Imaging"". Paris 6, 2008. http://www.theses.fr/2008PA066253.
Pełny tekst źródłaCarette, Michel. "Etude expérimentale d'une source ionique par capture d'électrons d'atomes excités dans des états de Rydberg : application à la spectrométrie de masse de polluants atmosphériques". Aix-Marseille 1, 1999. http://www.theses.fr/1999AIX11065.
Pełny tekst źródłaJardin-Mathé, Olivia. "Développement d'un logiciel universel d'imagerie par spectrométrie de masse et application au modèle sangsue et aux maladies neurodégénératives". Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10033/document.
Pełny tekst źródłaDirect analysis of tissues by MALDI mass spectrometry is a growing approach, and very important especially conceming biopsy analysis. It offers the interest to avoid extraction, purification and preparation of the sample. Moreover it allows to get additional information by preserving composite localization in the tissue thanks to the analysis realized in situ by a laser beam scan. The automation ofthis scan enables creation ofa matrix (signal intensity versus X y coordinates); thus data conversion by bioinformatics' software is the keystone of this technology. Access to direct data, independently from the manufacturer, accessibility to computing parameters allowing the creation of the picture and transparency have been our priorities during the creation of our new imaging software: MITrCS. ln order to illustrate the efficiency of this pro gram, the survey of the medicinal leech embryos proteome versus medicinal leech adult proteome was undertaken in order to search peptides presents in the embryo that are re-expressed in the adult during nervous regeneration. This work on this invertebrate has next been compared to studies realized on 6hydroxydopamin-treated animaIs in order to simulate Parkinson disease. Research of biomarkers and achievement of a molecular map linked with the Parkinson pathology should allow a correlation between biomarkers from nervous regeneration. But identified peptides still needs to be named, so 1 participated to the annotation of medicinal leech nervous system EST. Thanks to these EST, it williater be possible with MITrCS to correlate the picture to the name of the identified biomolecule in order to better apprehend its function
Cazier, Hélène. "Développement d’une nouvelle approche combinant la radioimagerie et l’imagerie par spectrométrie de masse pour l’analyse de nanoparticules". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS399.
Pełny tekst źródłaThe vectorization of drugs, which allows them to be transported to target tissues to increase their pharmacological activity while limiting their toxicity and adverse effects, is a rapidly expanding research area in which nanotechnologies are one of the key factors. One of the challenges in this thesis was therefore to develop a combined imaging method between MSI and imaging β for the study of the biodistribution of graphene-type nanoparticles. Despite the study of heterogeneous nanoparticles, the analyses determined a repeatable carbon signature of graphene oxide in LDI - MS analysis and reproducible MSI analyses with CVs below 30%. In addition, the combination of the two techniques made it possible to obtain the absolute quantification of GO in radioimaging after exposure of mice to three injection doses as well as the biodistribution at 25 µm of spatial resolution of these nanoparticles within tissues thanks to the contribution of MSI. In a second project to study polymeric micellar vectors encapsulating a drug, a MALDI - TOF method was also developed to detect these two molecules simultaneously. However, the experiments carried out have shown the need to develop tissue treatment protocols compatible with MSI and making it possible to improve the sensitivity threshold of this analytical technique
Sévelin-Radiguet, Nicolas. "Dispersions temporelles et énergétiques en émission ionique : application à la Sonde Atomique Tomographique assistée par laser". Rouen, 2014. http://www.theses.fr/2014ROUES064.
Pełny tekst źródłaAtom Probe Tomography is a nano-analysis technique able to map chemical species with atomic resolution in 3D within the sampled volumes. Surface atoms are field-evaporated from the specimen surface. Time-of-flight mass spectrometry assigns their chemical nature. Ultra-short laser pulses used to trigger the evaporation process allow analysing a broad range of materials (from metals to insulators). This thesis deals with two aspects of the use of ultra-short laser pulses in atom probe. The first part is an experimental and theoretical work about laser-assisted field evaporation mechanisms of silicon. Laser illumination and intense electric field confine carriers near the semi-conductor surface. Optical properties change and appear quasi-metallic. The second part of this thesis focuses on the energy spreads of the emitted ions. Various technological limitations previously hid this dispersion of energy. A new electrostatic lens allows us to measure such quantities. We show results on various materials (metals, semi-conductors and oxides) and suggest some possible explanations. Atom probe is not only a powerful analytical microscope but becomes an energy spectroscope as well
Oladipo, Adewale. "Désorption stimulée induite par des agrégats d'hydrogène (E ≤ 120 keV-u) et des ions lourds (E ≤ 400 keV-u) : applications analytiques". Lyon 1, 1988. http://www.theses.fr/1988LYO10032.
Pełny tekst źródłaPoncelet, Lauranne. "Utilisation de l'imagerie par spectrométrie de masse et son optimisation au cours du processus de développement de médicaments". Thesis, Lille, 2020. http://www.theses.fr/2020LILUS032.
Pełny tekst źródłaResearch and development (R&D) in the pharmaceutical industry is a crucial step for the discovery of new drugs or biomarkers. The development of new innovative treatments is a key driver of progress in the management of many diseases, such as periodontitis or immuno-oncology. This thesis work is initially interested in the place of mass spectrometry imaging using a matrix-assisted laser desorption ionization source (MALDI-MSI) during the development of new drugs, followed by its evolution reviewed (matrices, instruments and software) before illustrating several developments made with this technology to improve the detection of the compounds of interest (drugs / biomarkers), but also the quality of the results (quality of the samples or the quality of the analyze) with a view to standardization. Also, the implementation of quality controls and the validation of the quantification method improves the quality of the results. These developments then help pharmaceutical industries in the R&D stages, allowing them to combine this technology with their arsenal, in order to save time and money during the development stages of new drug candidates
Raujol, Julie. "Complémentarité du TOF-SIMS et du MALDI-TOF pour l'étude de l'hypoxie dans un modèle in vitro et in vivo". Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM5506.
Pełny tekst źródłaTissue or cells oxygenation results from a balance between oxygen availability and consumption. This availability is determined by the amount of oxygen carried by the blood irrigating the tissue and its diffusion capacity through the cell membranes. The interruption of blood flow or variations in the oxygen partial pressure are responsible for a reduction of oxygen intake that induces an adaptive response.The aim of my work is to characterize the hypoxia from cellular to tissue-level via the complementarity of two mass spectrometry imaging (MSI) methods: the Secondary Ion Mass Spectrometry (SIMS) and Matrix-Assisted Laser Desorption and Ionization (MALDI). MSI has the potential to provide detection, identification and distribution of a variety of different endogenous and exogenous molecular species directly from the tissue without labelling. Here we combine them to characterize hypoxia in vitro on a 3D cell culture system (spheroid) and in vivo using ischemic rat model.We have shown via TOF-SIMS imaging that reduced availability of oxygen to the center of spheroids induces profound metabolic changes. MALDI-TOF imaging helped to visualize the pharmacokinetics of different treatments in treated spheroids.Concerning the ischemic stroke, MSI provides a molecular signature of hypoxia in tissue, which could bring new insights into the pathological changes induced by the tissue injury.The complementarity of these two imaging techniques allows real synergy for the study of hypoxia in different models
Allali, Hakim. "Aspects de l'émission ionique secondaire induite dans des couches isolantes inorganiques par des ions d'Argon d'une dizaine de MeV". Phd thesis, Université Claude Bernard - Lyon I, 1993. http://tel.archives-ouvertes.fr/tel-00746656.
Pełny tekst źródłaFu, Tingting. "3D and High Sensitivity Micrometric Mass Spectrometry Imaging". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS218/document.
Pełny tekst źródłaMass spectrometry imaging has been shown of great interest in addressing biological questions by providing simultaneously chemical and spatial information. Particularly, TOF-SIMS is well recognized for its high spatial resolution (< 1 µm) which is essential in disclosing chemical information within a submicron area. The increasing use of TOF-SIMS in characterizing biological samples has greatly benefited from the introduction of new cluster ion sources. However, the ionization/desorption of the analytes under impacts of large clusters is still poorly understood. On the other hand, technically, current commercial TOF-SIMS instruments generally cannot provide sufficient mass resolution or mass accuracy for molecular identification, making analyses of complex biological systems especially challenging when no MS/MS fragmentation is available. Thus this thesis is aimed to get a better understanding of ion production under cluster impacts, to explore the MS/MS capability of the parallel imaging MS/MS Spectrometer (PHI nanoTOF II), as well as to apply TOF-SIMS to map important wood metabolites with high spatial resolution.In order to understand ion production under impacts of massive argon clusters, internal energy distributions of secondary ions were measured using survival yield method which involves the analyses of a series of benzylpyridinium ions. Investigation of various impacting conditions (energy, velocity, cluster size) suggested that velocity of the clusters play a major role in internal energy distribution and molecular fragmentation in the low energy per atom regime (E/n < 10 eV). The MS/MS fragmentation and parallel imaging capabilities of the newly designed PHI nanoTOF II spectrometer were evaluated by in situ MS/MS mapping of bioactive metabolites rubrynolide and rubrenolide in Amazonia wood species Sextonia rubra. Then this parallel imaging MS/MS technique was applied to perform in situ identification of related precursor metabolites in the same tree species. 2D and 3D TOF-SIMS imaging were carried out to target the plant cells that biosynthesize rubrynolide and rubrenolide. The results led to the proposal of a possible biosynthesis pathway of these two metabolites. In addition, to expand the application of TOF-SIMS imaging in wood chemistry analysis, radial distribution of wood extractives in the heartwood of European larch was also investigated
Le, Maître Johann. "Développement de la spectrométrie de masse à ultra- haute résolution associée à la spectrométrie de mobilité ionique pour la caractérisation de coupes pétrolières lourdes. structural analysis of heavy oil fractions afterr hydrodenitrogenation by high-resolution tandem mass spectrometry and ion mobility spectrometry Structural analysis of neutral nitrogen compounds refractory to the hydrodenitrogenation process of heavy oil fractions by high-resolution tandem mass spectrometry and ion mobility-mass spectrometry Chemical characterization of 15 biocrudes obtained from hydrothermal liquefaction of industrially cultivated wild micro algae Chemical characterization with different analytical techniques, a way to understand the process: Case of the paraffinic base oil production line Exploring complex mixtures by cyclic ion mobility high-resolution mass spectrometry – Application towards Petroleum. Simulation and modeling of Collision Cross Section for structural elucidation of heavy oil fraction by ion mobility-mass spectrometry: Using polyaromatic hydrocarbons compounds mixture as calibration standard Characterization of sulfoxides compounds in dimeric distribution of heavy oil fractions by positive-ion electrospray ionization FTICR mass spectrometry Structural analysis of Petroporphyrins from asphaltene by trapped ion mobility coupled with a Fourier transform ion cyclotron resonance mass spectrometer. Cyclic ion mobility spectrometry coupled to high-resolution time-of-flight mass spectrometry equipped with atmospheric solid analysis probe for the molecular characterization of combustion particulate matter. Structural study of analogues of Titan’s haze by trapped ion mobility coupled with a Fourier transform ion cyclotron mass spectrometer". Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR051.
Pełny tekst źródłaThe evolution of oil reserves requires the use in refineries of unconventional crude oils, which are often heavier and therefore difficult to characterize. Petroleum products are in fact extremely complex chemical mixtures. The light and volatile part can be analysed by gas chromatography coupled with mass spectrometry (GC/MS), allowing the identification of compounds by using precise mass measurements and fragmentation models. However, these techniques are inappropriate for the analysis of heavy fractions. In practice, the characterization of the most complex mixtures involves the use of ultra-high-resolution mass spectrometers generally by direct analysis without chromatographic separation. The reference technique today is Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR). With a resolution of more than 106 and a mass measurement accuracy of less than 0.1 ppm, this instrument can separate all the species present in a petroleum product and assign a unique elemental composition to each m/z value. This makes it very easy to obtain molecular maps that can be presented graphically using the Kendrick diagram, the van Krevelen diagram or the number of unsaturations (DBE) as a function of the number of carbons. This thesis work has allowed thanks to the molecular characterization of petroleum products (Vacuum Gas Oil, Crude Oil, Interfacial Material, Asphaltenes and Bio-Oil...) addressing the complexity of their treatment in the refining tool. Protocols for sample analysis have been developed, using different sources of ionization at atmospheric pressure (ESI, APCI and APPI) as well as laser desorption/ionization (LDI) on the FTICR 12T mass spectrometer. Information on the isomeric content of petroleum products was then determined using ion mobility spectrometry (IMS)
Lefévre, Soizic. "Caractérisation de la qualité des raisins par imagerie". Electronic Thesis or Diss., Reims, 2023. http://www.theses.fr/2023REIMS017.
Pełny tekst źródłaIdentifying the health conditions of the grapes at harvest time is a major issue in order to produce quality wines. To meet this issue, data are acquired by spectrometry, hyperspectral imaging and RGB imaging on grape samples during harvest.Several pre-treatments adapted to each type of data are applied such as normalization, reduction, extraction of characteristic vectors, and segmentation of useful areas. From an imaging point of view, the reconstruction in false colors of hyperspectral images, far from reality, doesn’t allow to label all the intra-class diversity. On the other hand, the visual quality of RGB imaging enables accurate class labelling. From this labelling, classifiers such as support vector machines, random forests, maximum likelihood estimation, spectral mapping, k-means are tested and trained on labelled bases. Depending on the nature of the data, the most effective is applied to whole images of grape clusters or crates of grapes of several grape varieties from different parcels.The quality indices obtained from RGB image processing are very close to the estimates made by experts in the field
Santos, Tiago. "Role of proteome in biofilm development and adaptation of Listeria monocytogenes to controlled environments". Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC027/document.
Pełny tekst źródłaListeria monocytogenes is a Gram-positive bacterium implicated in serious food-borne infections. Most cases of human listeriosis are caused by the consumption of refrigerated ready-to-eat foods. The ability of these bacteria to survive and multiply in a wide range of harsh conditions make this pathogen a major concern in agro-food industries. These properties of L. monocytogenes are enhanced by its ability to form biofilms. The aim of this project was to explore the adaptation of this pathogen to dehumidification and low temperatures by two proteomic approaches. The first approach, based on the MALDI-TOF mass spectrometry imaging (IMS), allows the mapping of molecules from biological samples. This work aimed to develop this approach, considering a bacterial biofilm as a tissue, in order to access information on the distribution of proteins in L. monocytogenes biofilms subjected to a dehumidification stress. In addition, an LC-MS/MS approach was used to link spectral data of interest obtained by IMS and protein identification. The IMS allowed to examine the distribution of 47 low molecular weight proteins within the biofilms. Five identified proteins were assigned by LC-MS/MS using IMS m/z data, including two cold-shock proteins. The results demonstrate that imaging can be used to dissect the spatial proteome of a bacterial biofilm. The second proteomic approach consisted on a relative semi-quantitative label-free (shotgun proteomic) comparison of proteins expressed under different culture conditions. With the method, we explored protein expression according to the mode of growth (biofilm vs planktonic) and temperature (10°C, 25°C and 37°C). Throughout the 920 and 931 unique proteins identified, from sessile and planktonic cells, respectively, many are connected to basic cell functions, but some are linked with thermoregulation. A shift was observed in the proteome of L. monocytogenes biofilms compared to planktonic cells indicating different patterns of regulation according to the mode of growth. These comparisons of protein expression throughout several conditions (mode of growth and temperatures) will enrich databases and help to model regulatory circuitry that drives adaptation of L. monocytogenes to environments
Maillard, Julien. "Composition chimique du brouillard de Titan par mobilité ionique couplée à la spectrométrie de masse haute résolution Comparison of soluble and insoluble organic matter in analogues of Titan's aerosols Optimization of ion trajectories in a dynamically harmonized Fourier-Transform Ion Cyclotron Resonance cell using a Design of Experiments strategy Structural Study of Analogues of Titan's Haze by Trapped Ion Mobility Coupled with a Fourier Transform Ion Cyclotron Mass Spectrometer. High resolution mass spectrometry for future space missions: comparative analysis of complex organic matter with LAb-CosmOrbitrap and LDI-FTICR. Structural elucidation of soluble organic matter: Application to Titan's haze. Dark-ageing of analogues of aerosols in the atmosphere of the early Earth". Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASV023.
Pełny tekst źródłaAlthough the prebiotic challenge is important, the study of aerosols in the atmosphere of Titan, Saturn's largest moon, remains a challenge for the scientific community. Indeed, the data collected by the Voyager and Cassini-Huygens probes made it possible to retrieve the first information but not to unlock the secrets of this particle fog. The purpose of this thesis is to study the chemical composition of these aerosols through their reproduction on Earth. The first approach presented is molecular characterization using high resolution mass spectrometry. In this section, the comparison between the soluble and insoluble fraction of these samples and their ageing will be presented. Then, the investigation of the growth of these aerosols is presented through the use of tandem mass spectrometry. The last part of this thesis presents the study of the three-dimensional structure. For this purpose, ion mobility coupled with mass spectrometry has been used and will be reported in two parts, one in TWIMS-Synapt and the other in TIMS-FTICR. Finally, a study in Atomic Force Microscopy will be presented and will make it possible to show real structures of molecules present in aerosols thanks to the magnification provided by this type of microscope
Pillatsch, Lex. "Bombardement ionique O‾, F‾, Br‾ et l‾ en SIMS : génération par duoplasmatron et étude du potentiel analytique". Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL052N/document.
Pełny tekst źródłaSecondary Ion Mass spectrometry (SIMS) is a powerful surface analysis technique. The ionisation probability strongly depends on the chemical surface state. The generation of positive secondary ions can be enhanced by surface bombardment with electronegative elements.Due to the optical configuration of the CAMECA NanoSIMS 50, that necessitates an opposite polarity of incoming and ejected ions, analyses of positive ions are realized with primary O- ions, generated in a duoplasmatron ion source. As a consequence of the low O- brightness of the duoplasmatron source, the lateral resolution of the analyses on the NanoSIMS 50 is not satisfactory in the positive secondary mode. In this work, we studied the feasibility of different alternative negative primary ion beams. We investigated the possibility of F-, Cl-, Br- and I- ion generation with a duoplasmatron as a function of the source parameters, notably the magnetic field strength, the arc current and the total gas pressure. The ion current and the beam diameter were measured in order to determine the F-, Cl-, Br- and I- brightness of the source. A comparative study with the O- brightness demonstrates an increase of the F- brightness by a factor of 5.By using the F-, Cl-, Br- and I- bombardment, the sputtering yield, the concentration of implanted primary ions and the useful yield of different semi-conductor and metal samples were analysed. As a consequence of a low halogen concentration, related to etching effects, no enhancement of the useful yield could be noticed for the semi-conductors. For metals however (e.g. Ni, Cu and Ag), useful yield enhancements by up to a factor of 100 compared to the O- bombardment could be demonstrated
Bouslimani, Amina. "Etude de la pénétration et du métabolisme intra-tumoral de l'oxaliplatine : proposition d'un nouveau mécanisme d'action". Thesis, Montpellier 1, 2012. http://www.theses.fr/2012MON13506.
Pełny tekst źródłaOxaliplatin is an anticancer drug used in Heated Intraoperative Chemotherapy (HIPEC) to treat peritoneal carcinomatosis. In spite of HIPEC efficiency, oxaliplatin penetration in treated tumors is not very well known. Study of oxaliplatin penetration in tumors of patients suffering from CP and treated with HIPEC, was the first part of the research project. Furthermore, transport mechanisms of the drug to cell DNA are not well established. Nevertheless, hypotheses suggest that some sulfur metabolites of oxaliplatin, could constitute "tanks" which are able to transport drug until DNA. The second part of this project aimed to study more deeply the reactivity of oxaliplatin sulfur metabolites. We have developed a MALDI imaging mass spectrometry method, which allows studying the distribution of oxaliplatin and its metabolites in human tumors. Our results reveal a drug penetration limited to few millimeters and an exclusive detection of the oxaliplatin- methionine metabolite (Ox-M): a supposed "Inactive" metabolite, because of its stability that prevents its interaction with DNA. To provide evidence of Ox-M reactivity, we studied its interaction with oxaliplatin targets: guanine and DNA. Our results showed that Ox-M is able to release the active part of the molecule to interact with guanine, and to form adducts on oligonucleotides duplexes that mimic DNA structure. Moreover, Ox-M adducts induce an arrest of DNA elongation. These results suggest the implication of Ox-M in a new active pathway of oxaliplatin cytotoxicity