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Synthesis, structure and properties of Al-based borohydrides for hydrogen storage
Full text linkThis thesis is dedicated to chemistry and hydrogen storage properties of novel complex hydrides. The main efforts were focused on synthesis and characterization of new Al-based borohydrides and amidoboranes. Somewhat different investigation on the hydrolysis of KBH4 in the atmosphere of CO2 was also performed. The series of mixed-cation M[Al(BH4)4] (M = Li+, Na+, K+, NH4+, Rb+, Cs+) were successfully obtained by a reaction of the corresponding MBH4 with Al(BH4)3. This method provides a high theoretical hydrogen capacity and enables to store highly reactive and unstable Al(BH4)3 in a solid-state form. A good quality of the obtained samples allowed to solve their crystal structures using variable temperature synchrotron X-ray powder diffraction (XRPD). The thermal decomposition of M[Al(BH4)4] shows various pathways: Al(BH4)3 is released below 100 °C for M = Li+ and Na+, while heavier derivatives evolve hydrogen and diborane at about 150 °C. Li[Al(BH4)4] firstly decomposes into Li4Al3(BH4)13 at ~60 °C, desorbing Al(BH4)3, and the latter decomposes at ~90 °C releasing the rest of the starting borohydrides. NH4[Al(BH4)4] occupies a special position, as it contains protic and hydridic hydrogens, recombining into hydrogen already at 35 °C. In general, the experimental decomposition temperatures of metal borohydrides linearly correlate with the square root of the ionic potential of metal atoms calculated from dynamical charges on cations. Al(BH4)3 reacts with ammonia borane, NH3BH3, producing mononuclear Al(BH4)3·NH3BH3 complex. It releases at ~70 °C two equivalents of hydrogen, showing considerably lower decomposition temperature, compared to pure NH3BH3. The striking property of this system is an endothermic dehydrogenation on the first decomposition step, compared to the exothermic one for ammonia borane and its other known complexes. This opens a possibility for its direct rehydrogenation. The main drawback of this system is the low stability of the dehydrogenation intermediate, Al(BH4)3·NHBH, decomposition above 100 °C. In order to suppress its decomposition, we investigated N-substituted derivatives of ammonia borane, obtaining a more promising complex, Al(BH4)3·CH3NH2BH3. Al(BH4)3 serves as a template in the potentially reversible ammonia borane dehydrogenation, with Al atom coordinating both the starting and the final products. Aiming to substitute highly reactive Al(BH4)3 by a halide salt, and using N-substituted NH3BH3, we obtained an ionic form of AlCl3·CH3NH2BH3, namely [Al(CH3NH2BH3)2Cl2][AlCl4]. The further analysis of these compounds will help to define a system for the reversible storage of hydrogen in ammonia borane. A different way to obtain hydrogen using new Al-based reactive hydride composite (RHC) was also explored in this work. In particular, NaAlH4–4NH3BH3 system showed fascinating properties of releasing high purity H2 and low hydrogen release temperature of 70 °C and formation of Na[Al(NH2BH3)4]. The properties of the first Al-based amidoborane look promising. This compound decomposes in two steps with the formation of NaBH4, 8 equivalents of pure hydrogen and an amorphous product AlN4B3H(0÷1.8). The latter reversibly reabsorb about 27% of released hydrogen. The example of Na[Al(NH2BH3)4] decomposition to AlN4B3H(0÷1.8) requires further in-depth studies, viz. its chemical structure and an optimization of the rehydrogenation process. The interest in Al-based complex hydrides has been growing during the last years. Any knowledge about new Al-containing complex hydrides is very important for the future solid-state hydrogen storage. Data obtained in this work might be important in the further predictions of potential RHC systems, applying the computational methods. On the practical side, the combination of any of the described compounds with other hydrides may open avenues to new RHCs with enhanced hydrogen storage properties.(SC - Sciences) -- UCL, 2015Accès libre03/12/2015(SC - Sciences) -- UCL, 2015Anglai
Welfare and behavior micro-analysis of economies with agents exhibiting non-classical preferences
Full text linkThis dissertation in microeconomic theory is composed of four chapters. The first two chapters investigate two closely related normative questions. How can we compare different distributions of a multi-goods endowment among individuals that care for their relative situation? How can we compare the poverty in different income distributions when both the absolute and relative aspects of income matter? The outputs of these chapters are indicators able to rank economic outcomes as a function of their adequacy with the principles of Pareto efficiency and equality of resources. The third chapter aims at comparing different mechanisms used for the allocation of economic resources among individuals holding private information, e.g. their preferences over these resources. This implies studying both the incentives these mechanisms provide and the properties of the allocations to which they lead. The chapter proposes a general criterion for comparing the performance of allocation mechanisms and apply this criterion to the stability of school choice mechanisms. The last chapter focuses on the strategic interactions between individuals averse to ambiguity. It proposes a new interpretation for equilibria in ambiguous randomization strategies.(POLS - Sciences politiques et sociales) -- UCL, 2015Accès libre08/12/2015(POLS - Sciences politiques et sociales) -- UCL, 2015Anglai
Role of macrophages from LDV-infected mice in the onset of blood autoimmune diseases
No full textEnvironmental factors such as invading pathogens modify the microenvironment of the host. Since the microenvironment is responsible for the differenciation of immune cells and their subsequent effectors functions, modification of this microenvironment is responsible for a modulation of immune responses. Further, viral infections have been associated with the development of autoimmunity through several mechanisms including immunomodulation. During LDV infection, many cytokines are produced including both type I and type II IFNs which are known to be involved in macrophage differenciation. IFN-γ activates the phagocytic activity of macrophages, and therefore enhances the pathogenicity of self-reacting antibodies leading to an exacerbation of blood autoimmune diseases, while type I IFNs play a protective role by reducing phagocytosis of these immune complexes. We found that activating FcγRs are necessary to the development of severe anemia in infected mice treated with IgG2a anti-red blood cell antibodies. We analysed the mechanisms triggered by both type I and type II IFNs on the expression of FcγRs and showed an opposite regulation for FcγR I and FcγR IV by these cytokines that could not fully explain the protective role of type I IFNs in vivo. LDV infection also exacerbates the pathogenicity of IgM anti-platelet antibodies leading to the development of autoimmune thrombocytopenia (AITP). To date no receptor mediating uptake of IgM-opsonized particules could be incriminated in the disease. We therefore investigated the involvement of the recently discovered FcαμR, the only IgM receptor expressed by macrophages and showed a role of this receptor in IgM-mediated thrombocytopenia. Finally, we showed that the modifications of the microenvironment triggered by LDV lead to the differenciation of macrophages into an atypical M1 since they express many markers of M1 but also a few markers of M2 macrophages. They have reduced ability to induce T cell proliferation and decreased redifferenciation abilities although they exhibit enhanced phagocytosis leading to the exacerbation of both AIHA and AITP.(BIFA - Sciences biomédicales et pharmaceutiques) -- UCL, 2015Accès restreint23/11/2015(BIFA - Sciences biomédicales et pharmaceutiques) -- UCL, 2015Anglai
Search for Higgs bosons decaying to tau leptons with the CMS experiment at the LHC
No full textWith the first LHC proton-proton (p-p) collisions at a center-of-mass energy of 7 TeV occurred in spring 2010, the world witnessed the beginning of a new era in particle physics. From that milestone onward, the Standard Model (SM), the theory that describes matter constituents and their interactions, has been further verified and a large number of searches for new phenomena have been performed. The SM foresees the existence of the Higgs boson, which is the particle that gives mass to fermions and gauge bosons. The discovery of a SM Higgs-like particle in bosonic channels has been announced on July 2012 by the ATLAS and CMS experiments at LHC. Signals of such a particle in the fermionic decay channels were, instead, still not revealed when the work presented in this thesis started. Moreover, it is known that the SM has limitations which might be explained by extended theoretical scenarios. This thesis has dealt on one side with finding traces, with the CMS experiment, of the SM Higgs boson decay in the fermionic channels and on the other with finding evidence of possible scenarios beyond the SM. In the former context, the search for the SM Higgs boson h decaying into a pair of tau leptons and produced in association with a Z boson decaying into either a dielectron or dimuon pair, has been performed. By combining the result of this search with a few others, evidence for the decay of the newly discovered particle in the ditau channel has been found, demonstrating its Higgs-like nature as predicted by the SM. In the second part of the thesis, a search for a new resonance decaying to a Z boson and a lighter resonance, as predicted by models with two Higgs doublets (2HDM, which are extensions of the SM), has been performed. The decay of the Z boson into dilepton pairs and that of the light resonance into a pair of tau leptons have been considered. With no significant excess observed over expected backgrounds, 95% confidence level (CL) exclusion limits on the signal cross section have been set. The performance of the algorithm used in the CMS experiment to reconstruct and identify tau leptons, crucial for the analyses presented in this thesis, have also been widely studied and presented in this manuscript.(SC - Sciences) -- UCL, 2015Accès restreint09/10/2015(SC - Sciences) -- UCL, 2015Anglai
Design of multi-stimuli responsive films through layer-by-layer assembly for the control of protein adsorption
No full textProtein adsorption on a solid artificial surface is a fundamental phenomenon that determines the biological response of a living organism entering any implant material. Therefore, tailoring surfaces for controlled protein adsorption is at the heart of many of today's research fields including biotechnology and materials science. In this context, stimuli-responsive materials that are able to change their properties as a response to a small change in their physico-chemical environment are attracting a great interest as they allow the creation of surfaces with switchable properties for the control of protein adsorption. In this thesis, we report on the design and elaboration of multi stimuli-responsive thin films and nanotubes. For this purpose, we employed the robust and versatile layer-by-layer (LbL) assembly technique to incorporate block copolymers made of poly(acrylic acid) PAA and poly(N-isopropylacrylamide) PNIPAM with tunable and well-controlled block lengths. The combination of ellipsometry, quartz crystal microbalance with dissipation monitoring (QCM-D), surface plasmon resonance (SPR) and infrared data reveal the possibility to build up (PAH/PAA-b-PNIPAM)n multilayers. The stimuli-responsive properties of these LbL films were examined by monitoring the adsorption of proteins by means of QCM-D and fluorescence measurements, while varying (i) temperature, (ii) pH, (iii) ionic strength, or (iv) a combination of the above parameters. It appears that all these stimuli strongly influence the amount of adsorbed proteins. In short, these new PNIPAM block copolymer-based LbL coatings are easy to build on substrates of various nature and geometry (including nanoporous membranes) and they present highly tunable features. This makes them ideal candidates to be employed for applications requiring the control of protein adsorption, such as protein separation or cell culture.(FSA - Sciences de l'ingénieur) -- UCL, 2015Accès restreint16/10/2015(FSA - Sciences de l'ingénieur) -- UCL, 2015Anglai
Vers la synthèse totale de l'acide okadaïque
No full textLeading member of the diarrheic shellfish poisoning family, okadaic acid, a natural polyether produced by dinoflagellates, has been shown to be a very interesting biochemical tool. Its potent and selective inhibition of protein phosphatases 1 and 2A (PP1 and PP2A) made it one of the most used mechanistic probe for understanding those enzymes related processes. During this PhD thesis, we undertook the synthesis of okadaic acid based on a three fragments disconnection. The core of the Western fragment was built with the help of allylselenide chemistry, who could easily be converted to allyllithium after addition of n-BuLi. Then, the ISMS methodology allowed us to get a racemic model of the first cycle of the Central core. Finally, two different methodologies were used to synthetize the Eastern fragment of the polyether. Taddei-Ricci modified conditions, followed by photochemical Suárez oxidation, were the key steps of the first route and electrochemical oxidation of a malonic acid were used as a key step in the second route.Toxine principale responsable des intoxications alimentaires dues aux fruits de mers, l’acide okadaïque, un polyéther marin issu de dinoflagellés, s’est montré un outil biochimique particulièrement intéressant. Ses propriétés d’inhibition puissante et sélective des protéines phosphatases 1 et 2A (PP1 et PP2A) en ont fait l’une des sondes mécanistiques les plus utilisées pour la compréhension de processus impliquant ces enzymes. Au cours de cette thèse, nous nous sommes attelés à la synthèse de l’acide okadaïque en s’appuyant sur une découpe en trois fragments. Le noyau du fragment Ouest fût construit à l’aide de la chimie des séléniures allyliques, qui peuvent facilement être transformés en allyllithiens sous l’action de n-BuLi. La méthodologie ISMS nous permit ensuite d’assembler un modèle racémique du premier cycle du fragment Central. Enfin, deux méthodologies distinctes nous permirent d’obtenir le fragment Est du polyéther. Les conditions modifiées de Taddei-Ricci, suivies de l’oxydation photochimique de Suárez, constituèrent la première route tandis que l’oxydation électrochimique d’un acide malonique servit d’étape clé à la deuxième voie.(SC - Sciences) -- UCL, 2015Accès embargo09/10/2015(SC - Sciences) -- UCL, 2015Françai
Sujets de l'émancipation :savoirs sur la langue, gouvernementalité, pratiques pédagogiques
No full textThe scope of this thesis consists in the radicalization of the discourse about emancipation occurring in the social and political context of post-soviet Moldavia. The work of Michel Foucault was the central reference point of our approach. The use of theoretical instruments elaborated in The order of things and The archaeology of knowledge is important to understand the discursive conditions of existence of knowledge about language with respect to the relationship the latter stand with political power. In this thesis, the analysis of knowledge about language is not exhausted by the realm of discursive practice. It is simultaneously situated at the level of the action of subjects. In this particular point of view, the foucaldian genealogy opens a new field of analysis insofar it is not limited to the description of the functioning of social institutions. This new kind of analysis consists in the conceptualizing of power as action upon the action of others. The emancipation, in this perspective, is to be understood as the creation of concepts responding to the blockages that impede the deployment of the action upon the action of others. Through an analysis of the nature of the relationship that can be established between archaeology and genealogy, this thesis explores the structure of the discourse about emancipation in post-soviet Moldavia and proposes a new interpretation of Michel Foucault’s work.Cette thèse relève d’une tentative de radicalisation du discours sur l’émancipation situé dans la conjoncture sociale de la Moldavie d’après la chute de l’Union Soviétique. Ce sont les ouvrages de Michel Foucault qui ont été le point de repère central pour nous orienter dans cette démarche. L’usage des instruments théoriques forgés par Foucault dans Les mots et les choses et dans L’archéologie du savoir s’avère important pour mieux comprendre les conditions d’existence archéologique du savoir sur la langue dans son rapport avec le pouvoir politique. Dans cette thèse, l’analyse du discours sur l’émancipation ne s’épuise pas sur le niveau du savoir sur la langue en tant qu’il est l’effet historique d’une pratique discursive. Elle se situe simultanément sur le niveau de l’action des sujets. Sur ce point, la généalogie foucaldienne du pouvoir ouvre un champ nouveau d’analyse dans la mesure où elle ne se contente pas de problématiser le fonctionnement des institutions dans une société donnée. Ce champ nouveau consiste dans l’analyse du pouvoir en tant qu’action sur l’action des autres. L’émancipation, selon cette perspective, consiste dans la création des concepts comme tout autant de réponses à la singularité des blocages qui empêchent le déploiement de l’action sur l’action des autres. En thématisant la nature du lien que l’on peut établir entre l’archéologie et la généalogie, l’effort de cette thèse consiste à la fois dans l’approfondissement du discours sur l’émancipation dans la Moldavie Soviétique et dans une nouvelle interprétation de l’œuvre foucaldienne.(FILO - Philosophie) -- UCL, 2015Accès embargo23/09/2015(FILO - Philosophie) -- UCL, 2015Françai
New prognosis markers and new targets for therapy in high risk melanoma: evaluation of TYRP1 as a melanoma prognostic marker and its regulation by miRNA(s)
No full textL’espérance de vie des patients atteints de mélanome à haut risque ne peut être prédite d’une façon<p>fiable en se basant sur les analyses d’histopathologies de la lésion primitive et est souvent ajustée<p>durant la progression de la maladie. Notre étude vise à élargir nos observations initiales au niveau<p>des métastases cutanées et d’évaluer la valeur pronostique de tyrosinase related protein 1 (TYRP1)<p>dans les métastases ganglionnaires des patients atteints de mélanome de stades III et IV. TYRP1 est<p>une enzyme mélanosomale qui partage des similitudes structurelles avec la tyrosinase, l'enzyme clé<p>de la mélanogenèse.<p>L’expression de l'ARNm de TYRP1 a été quantifiée dans 104 métastases ganglionnaires par PCR<p>en temps réel et normalisée par rapport à l’expression de l’ARNm de S100B (marqueur reconnu du<p>mélanome) pour corriger l’expression de TYRP1 suivant la charge tumorale de l’échantillon. Le<p>rapport TYRP1/S100B a été calculé et la médiane a été utilisée en tant que valeur seuil. Ensuite<p>nous avons étudié la relation entre les valeurs de TYRP1/S100B, le suivi clinique et les<p>caractéristiques histopathologiques de la tumeur primitive.<p>Un rapport élevé de l’ARNm TYRP1/S100B corrélait significativement avec une survie sans<p>récidive et une survie globale plus courtes, avec une épaisseur de Breslow plus élevée et avec la<p>présence d'une ulcération au niveau de la tumeur primitive. En outre, une expression élevée de<p>TYRP1/S100B était de meilleure valeur pronostique pour la survie globale que l'épaisseur de<p>Breslow et l'ulcération des primitifs. De plus, cette expression est bien conservée au cours de la<p>progression de la maladie par rapport aux groupes de TYRP1 bas/élevé.<p>Nous avons constaté qu’une expression élevée de TYRP1/S100B dans les métastases de patients<p>atteints de mélanome est associée à un résultat clinique défavorable et une survie courte. Menée sur<p>des patients atteints d'un mélanome à haut risque de récidive, cette première étude a suggéré que<p>l'ARNm de TYRP1 dans les métastases pourrait servir de biomarqueur pour affiner le pronostic<p>initial des patients surtout ceux ayant des lésions primitives de localisation inconnues ou non<p>évaluables et peut permettre une gestion différente des deux groupes de patients. Son expression<p>conservée au cours de la progression de la maladie est en faveur de son utilisation comme cible<p>thérapeutique.<p>En second lieu, en évaluant l’expression de la protéine TYRP1 par immunohistochimie dans les<p>métastases cutanées et ganglionnaires, nous avons observé qu’elle n'était pas détectée dans la moitié <p>7<p>des tissus exprimant bel et bien l'ARNm correspondant et qu’elle, contrairement à l'ARNm, n’était<p>pas associée à la survie.<p>Des données récentes ont indiqué que le 3'-UTR de l’ARNm de TYRP1 contient trois sites de<p>liaison putatifs de miR-155 dont deux présentant un polymorphisme d'un seul nucléotide (SNPs:<p>rs683 et rs910) qui favorisent la dégradation en cas d’hybridation miARN-ARNm parfaite de<p>l’ARNm ou non en cas d’hybridation imparfaite. Nous avons cherché à examiner si miR-155 peut<p>affecter l’expression de l’ARNm et de la protéine TYRP1 en fonction de ces SNPs. Tout d'abord,<p>nous avons transfecté deux lignées de mélanome ayant chacune l’une ou l’autre de l’allèle (au<p>niveau rs683 et rs910) avec différentes concentrations de pré-miR-155 et nous avons évalué<p>l’expression du miR-155 et l’ARNm TYRP1 par PCR en temps réel ainsi que l’expression de la<p>protéine TYRP1 par western blot. Nous avons constaté qu’une surexpression de miR-155 a induit<p>une dégradation importante des ARNm TYRP1 et a perturbé sa traduction en protéine dans la lignée<p>avec le génotype “hybridation parfaite”. Ensuite, nous avons examiné l'expression des ARNm et<p>protéines de TYRP1, le niveau de miR-155 et les SNPs rs683 et rs910 dans 192 échantillons de<p>métastases cutanées et ganglionnaires de mélanome. Nous avons trouvé que le groupe d'échantillons<p>avec le génotype “hybridation parfaite” était significativement associé à un niveau de protéine de<p>TYRP1 plus bas alors qu'aucune différence de niveau d’expression n'a été trouvée pour l’ARNm de<p>TYRP1 ou miR-155 entre les deux groupes de génotype, confirmant que les SNPs au niveau de 3’-<p>UTR de TYRP1 peuvent spécifiquement affecter l'expression de la protéine TYRP1. En outre, nous<p>avons montré que l’ARNm de TYRP1 est inversement corrélé avec l’expression miR-155, mais pas<p>avec la protéine TYRP1 dans le groupe " hybridation parfaite", alors qu'il corrèle positivement avec<p>la protéine mais pas avec miR-155 dans le groupe "hybridation imparfaite" où la protéine corrélait<p>inversement à la survie. Cela montre que les SNPs dans le 3'-UTR de l'ARNm TYRP1 affectent la<p>régulation de l’ARNm par miR-155 et la traduction en protéine. Ces SNPs rendent la régulation de<p>l’ARNm et la protéine de TYRP1 indépendante de miR-155 et confèrent une valeur pronostique à<p>la protéine TYRP1Doctorat en Sciences biomédicales et pharmaceutiquesinfo:eu-repo/semantics/nonPublishe
Real Time Surface Plasmon Resonance Biosensors, a Powerful Technology to Assess Polyclonal Antibody Avidity
No full textThe present research focused on the development of a new methodology to assess the strength of the interaction between vaccine antigens and elicited polyclonal antibodies through SPR biosensors. Quantifying the binding strength of polyclonal antibodies is of first importance to evaluate the quality of the vaccine as well as to increase the scientific knowledge of immune protection mechanisms. To now the development of such tool has been complicated by the non-specific binding caused by high protein abundance in the blood and serum samples but also by the way of interpreting the data resulting from multi-interaction events measured at the same time. At first, we unsuccessfully tried to segregate the individual affinity contribution of each antibody population by measuring the signal as the sum of singular interactions. Differentiation of the singular contribution would have needed the fulfillment of the “additivity” hypothesis, meaning that each antibody bind identically alone or in mixture with other antibody. This hypothesis was not met and mathematical assessment by the sum of singular contribution led to fitting results that did not reflect the biological reality. It was therefore decided to switch the analysis method and to measure the end association binding level reached by the different samples injected at the same specific antibody content. The dissociation behavior was interpreted by the percentage of binding after long and fixed dissociation time. In a first application, we compared the antibodies elicited by two different commercially available vaccines and we showed that the binding interaction was not concentration dependent as, highly different levels were reached when injecting identical antibody concentration. No statistical significant difference was observed between both vaccines. Research firstly focused on the decrease of the non-specific binding and we found that ionic strength was a key parameter, increasing the buffer salt concentration reduced the non-specific binding without diminishing the binding strength. The sample composition was also a key parameter and purifying the IgG allowed to decrease dramatically the undesired binding events. A second application aimed at showing the equivalence between two different antigen constructions for two antibodies population. Even if identical antigen level immobilization is a challenge, the methodology is completely suitable to perform a 2-dimensional comparison (ligand and analyte). A last application was dedicated to the comparison between D and Q-pan Flu vaccines, and results showed that there was no statistical evidence of significant differences between both vaccines. End association level correlated well with haemagglutination inhibition assay at least when serum samples were not diluted at the same antibody content. This last application also showed that throughput may be extended to more than 50 samples per 80 hoursDoctorat en Sciences agronomiques et ingénierie biologiqueinfo:eu-repo/semantics/nonPublishe
Ambulatory diagnostic and monitoring techniques for sleep disordered breathing.
No full textTechniques ambulatoires de diagnostic et de monitoring des troubles respiratoires liés au sommeil.Le syndrome d’apnées obstructives du sommeil (SAOS) est un trouble du sommeil très fréquent, fortement lié à l’obésité, ce qui explique sa prévalence en pleine expansion. En parallèle, la demande d’examens polysomnographiques (PSG) en laboratoire du sommeil, méthode diagnostique de référence, est en croissance. Comme l’accès à cette technique est peu aisé, de nombreux appareils simplifiés d’enregistrement de sommeil ont été récemment développés, mais restent imparfaits (mauvaise évaluation du temps de sommeil, sous-estimation de la sévérité du SAOS, faux négatifs, taux d’échec élevé) et sont d’un apport limité pour le diagnostic du SAOS. La PSG au domicile (PSG-d) est une alternative bien plus informative, permettant d’éviter nombre des désavantages rencontrés par l’usage d’appareils simplifiés. Nous l’avons dès lors étudiée pour le diagnostic du SAOS, au travers d’une étude randomisée comparant la PSG-d vs la PSG hospitalière. En termes d’efficacité diagnostique, les résultats sont excellents, avec un faible taux d’échec d’examens à domicile (4.7 vs 1.5%). Les patients préfèrent être enregistrés dans leur propre environnement où la qualité de leur sommeil est d’ailleurs meilleure. Nous avons ensuite voulu faire le point sur la littérature récente au travers d’un article de revue, en analysant les études prospectives randomisées comparant la PSG-d et au labo du sommeil. Les résultats de ces études concordent pour démontrer que la PSG-d constitue une excellente alternative aux tests réalisés à l’hôpital. Outre le SAOS, l’outil permet le diagnostic d’autres troubles du sommeil, comme les mouvements périodiques des jambes durant le sommeil, les troubles du rythme circadien, Une question restée jusqu’ici sans réponse était l’influence de la localisation du branchement des PSG-d, à l’hôpital ou à domicile. Une étude prospective randomisée nous a permis d’établir que la localisation du branchement des PSG-d n’influençait pas la qualité globale de l’examen, ce qui simplifiera l’utilisation de cet outil à l’avenir. Enfin, nous avons utilisé des techniques de télé monitoring (TM) pour contrôler, en temps réel, la qualité des PSG-d. Dans une première étude pilote, la faisabilité a été confirmée, malgré quelques difficultés techniques. Nous avons voulu appliquer la technique à une population de patients souffrant d’un syndrome coronarien aigu, incapables d’être enregistrés au labo du sommeil. Nous avons étudié la qualité du screening du SAOS par PSG vs polygraphie (PG). Les résultats se sont révélés surprenants :82% de cette population présentait des troubles respiratoires liés au sommeil, principalement centraux. La PSG était nettement plus sensible que la PG, et le TM améliorait la qualité des PSG. Chez les patients traités pour SAOS, nous avons ensuite utilisé un outil de monitoring, l’actigraphie (Act), afin d’observer, dans la vie de tous les jours, les changements de schémas de sommeil et d’activité physique engendrés par la pression positive continue (PPC). Dans un premier travail, rétrospectif, nous avons observé ces paramètres chez des SAOS avant traitement, puis au travers d’une étude prospective multicentrique, nous avons suivi 150 patients avant et après PPC, et observé chez eux une augmentation de temps de sommeil, mais pas de l’activité physique. En conclusion, nous avons démontré dans cette thèse l’intérêt clinique de deux excellents outils ambulatoires, la PSG-d et l’Act, pour la prise en charge du SAOS. Les implications potentielles sont une meilleure accessibilité diagnostique pour le SAOS, une initiation thérapeutique plus précoce et un suivi plus précis des SAOS traités, dans des conditions ambulatoires, plus confortables et plus adéquates pour les patients.Ambulatory diagnostic and monitoring techniques for sleep disordered breathingSleep disordered breathing (SDB), including obstructive sleep apnea syndrome (OSAS), is directly related to obesity. Significant morbi-mortality is associated with OSAS, explaining the increasing demand for in-hospital polysomnography (PSG), the reference diagnostic method. As this technique is complex and time-consuming, many simplified portable monitoring (PM) devices for home sleep testing have been developed. However, the ability of PM devices to detect OSA remains limited: sleep time is not correctly assessed, OSA severity is underestimated, false negative results occur and the failure rate of the tests is high, up to 30%. Home-PSG (H-PSG) is an interesting alternative, avoiding many of these drawbacks. In the first part of this work, we studied the tool in an original study comparing H-PSG and in-lab PSG. Diagnostic efficacy was good and the failure rate low (4.7 vs 1.5%). Patients slept in their own environment and thus sleep quality was better. We were then interested by reviewing recent literature data regarding prospective randomised trials comparing H-PSG and in-lab PSG. We concluded that H-PSG is an excellent alternative for in-lab PSG, allowing not only OSA detection but also diagnosis of a large panel of other sleep disorders (periodic leg movements during sleep, circadian disorders,). As the best place to perform set-up for H-PSG remained unknown, we studied, in another prospective randomised study, the recording’s quality obtained in both settings. As no difference was observed, lab set up was found to be the simpler option for performing H-PSG. We then tested, in a prospective pilot study, real-time telemonitoring (TM) of H-PSG in order to enhance recording quality. Results were encouraging but we faced some technical problems. In a second study, we applied TM coupled with PSG to detect SDB in acute coronary syndrome, in patients too unstable to come in the sleep lab. We compared also PSG results to polygraphy (PG). Surprisingly, 82% of patients suffered from SDB. PSG was much more sensitive than PG to screen SDB in this population and TM improves recording quality. In the second part of this work, we have used actigraphy (Act) to assess sleep and physical activity in OSA patients in real-life conditions. Firstly, in a retrospective study, we documented these parameters before treatment. In a second multicentre study, we evaluated the changes in sleep schemes and physical activity under continuous positive airway pressure (CPAP) in 150 OSA patients. We observed that sleep time was increased under CPAP, but physical activity was not improved, contrarily to sleepiness and quality of life. In conclusion, we have shown through these works the clinical interest of two excellent ambulatory tools, H-PSG and Act, for OSA management. Potential clinical implications include enhanced healthcare accessibility, earlier treatment initiation and a closer follow-up of treated patients, through ambulatory tools, in a comfortable environment for the patients.Doctorat en Sciences médicales (Médecine)info:eu-repo/semantics/nonPublishe