Cette thèse décrit l'état de l'art des sondes et nanoparticules fluorescents traditionnels utilisés en imagerie de fluorescence ainsi que le développement de nouveaux nanomatériaux à base de polymère à empreinte moléculaire, aussi dénommé ‘anticorps plastique’, pour le ciblage et la bioimagerie. En biologie et en médecine, il y a un besoin constant de diagnostiquer diverses maladies pour leur éventuel traitement et prévention. Une distribution anormale et un taux élévé de glycosylation (e.g. acides hyaluronique et sialique) à la surface ou dans les cellules sont indicateurs d’une infection ou d’un cancer. Généralement, l’imagerie par fluorescence permet de visualiser, localiser et quantifier les biomarqueurs de pathologie mais à l’heure actuelle, il n’existe pas d’outil analytique fiable pour cibler spécifiquement les molécules de glycosylation car les anticorps et les lectines vendus dans le commerce ont une faible affinité et sélectivité vis-à-vis de ces cibles. Dans ce contexte, les polymères à empreintes moléculaires (MIPs) pourraient apporter une solution. Les MIPs sont des récepteurs synthétiques possédant des affinités et sélectivités comparables à ceux des anticorps, mais exhibant une stabilité physique, thermique et chimique bien plus accrue. De plus, leur fabrication est peu coûteuse et ne nécessite pas de tuer des animaux comme pour l’obtention des anticorps biologiques. Dans cette thèse, nous avons optimisé et synthétisé des MIPs biocompatibles pour leur utilisation en bioimagerie afin de détecter et quantifier l’acide hyaluronique et l’acide sialique sur les cellules et les tissus de peau humaine. L’acide glucuronique, une composante de l’acide hyaluronique et l’acide N-acétylneuraminique, l’acide sialique le plus commun, ont été utilisés comme molécules ‘patron’, générant des MIPs très sélectifs envers leur cible en milieu aqueux. Deux types de nanoparticules de MIPs fluorescents ont été synthétisés: (1) en incorporant un colorant rhodamine polymérisable dans la solution de pré-polymérisation et (2) en encapsulant des boîtes quantiques InP/ZnS générant ainsi des MIPs de type cœur-coquille. Pour cela, nous avons adopté une stratégie innovante qui consiste à synthétiser les coquilles de MIPs directement autour des boîtes quantiques en utilisant l’énergie de l’onde fluorescente émise par l’excitation des points quantiques, pour initier la polymérisation. Un protocole d'immunocoloration standard a ensuite été optimisé afin d’imager des kératinocytes humains fixés et vivants ainsi que des tissus de peau, par microscopie à épifluorescence et confocale. Les résultats étaient similaires à ceux obtenus par la méthode de référence utilisant une protéine biotinylée reconnaissant l'acide hyaluronique. L'imagerie multiplex en combinant deux MIPs couplés à deux couleurs de boîtes quantiques et l’imagerie des cellules cancéreuses ont également été démontrées. Bien que les MIPs n’étaient pas cytotoxiques aux concentrations utilisées pour la bioimagerie, la toxicité des différentes composantes du MIP pourrait être un frein à leur utilisation dans le domaine biomédical. Afin de rendre ces MIPs plus ‘inoffensifs’, nous avons supprimé l’amorceur de polymérisation, une molécule considérée comme toxique. Les MIPs ont été synthétisés en employant des monomères qui s’auto-initient sous l’effet de l’UV ou de la chaleur. La spécificité et la sélectivité des MIPs obtenus étaient similaires à ceux préparés avec des amorceurs. En conclusion, cette thèse décrit la première utilisation des MIPs comme anticorps synthétique pour la bioimagerie de fluorescence. Ce travail ouvre la voie à de nouvelles applications en détection, diagnostique et thérapie par des MIPs. / This thesis describes the state of the art in nanomaterials-based targeted bioimaging and introduces molecularly imprinted polymers, also termed ‘plastic antibodies’ as novel biorecognition agents for labeling and imaging of cells and tissues. In fundamental biology and medical diagnostics, there is a constant need to localize and quantify specific molecular targets. Abnormal glycosylation levels or distributions of hyaluronan or sialic acids on cells are indicators of infection or malignancy. In general, bioimaging with fluorescent probes enables the localization and qualitative or quantitative determination of these pathological biomarkers. However, no reliable tools for the recognition of glycosylation sites on proteins exist, because the commercially available antibodies or lectins have poor affinity and selectivity for these targets. In this context, tailor-made molecularly imprinted polymers (MIPs) are promising synthetic receptor materials since they present a series of advantages over their natural counterparts such as the ease and low cost of preparation and their physical and chemical stability. Thus, MIPs could provide a robust and specific imaging tool for revealing the location/distribution, time of appearance and structure of glycosylation sites on/in cells, which would lead to a better insight of the tremendously diverse biological processes in which these molecules are involved. Herein, we describe the synthesis of water-compatible MIPs for the molecular imaging of hyaluronan and sialylation sites on cells and tissues. Since molecular imprinting of entire biomacromolecules like oligosaccharides is challenging, we opted for what is commonly called the ‘epitope approach’, which was inspired by nature. The monosaccharides, glucuronic acid and N-acetylneuraminic acid were imprinted, and the resulting MIPs were able to bind these molecules when present and accessible on the terminal unit of hyaluronan and sialylation sites. Fluorescent MIPs were synthesized as rhodamine-labeled nanoparticles and as MIP-coated InP/ZnS core-shell quantum dot (QD) particles. For the coating of the QDs, a novel versatile solubilization and functionalization strategy was proposed, which consists of creating polymer shells directly on QDs by photopolymerization using the particles as individual internal light sources. A standard immunostaining protocol was then successfully adapted for the application of the fluorescently labeled MIPs to image fixed and living human keratinocytes and skin tissues, by epifluorescence and confocal fluorescence microscopy. The results were comparable to those obtained with a reference method where staining was done with a biotinylated hyaluronic acid binding protein. Multiplexed and cancer cell imaging were also performed, demonstrating the potential of molecularly imprinted polymers as a versatile biolabeling and bioimaging tool. Although the MIPs were not cytotoxic at the concentrations used for bioimaging, in order to render them generally applicable in biomedicine, where toxicity of the polymerization precursors is a matter of concern, we suppressed the initiator, a toxic chemical. Initiator-free MIPs were thus synthesized by using monomers that can self-initiate under UV irradiation or heat. The specificity and selectivity of the obtained MIPs were as good as the ones prepared with initiators. In conclusion, we have demonstrated for the first time the great potential of MIPs as synthetic antibody mimics for bioimaging. The possibility to associate other functionalities such as QDs and additionally attach drugs to the same material appears rather straightforward due to the synthetic polymeric nature of MIPs, which paves the way to new potential applications in theranostics.

Les missions internationales en entreprise ne parviennent plus à retenir les talents alors même que leur coût reste très élevé. La délocalisation de l’individu apparaît donc comme une nouvelle forme d'expatriation à mi-chemin entre expatriation auto-initiée et mission internationale en entreprise. Cependant, celle-ci résonne comme une violation du contrat psychologique liant l’individu à son entreprise. En effet, le diplôme ne semble plus protéger l’employé contre la délocalisation de son poste vers des pays à coût plus bas. Cette étude de cas a aidé à identifier les facteurs influençant les talents à accepter une relocalisation sous contrat local dans un pays à moindre coût. De ce fait, cette thèse fournit aux entreprises des éléments contributifs à la gestion globale des talents dans un contexte de délocalisation. / Individual offshoring emerges as a new form of organizational-initiated expatriation which bridges self-initiated-expatriation and international assignment. The failure of IA to retain talented individuals (talent) and a growing pressure on costs leave no choice to companies but to dramatically reconsider how expatriation can develop talent globally in a different but still sustainable way.However, this new form of expatriation resonates as a breach of the psychological contract. If talent no longer expect to remain in the same company for a large part of their career, they still hold an expectation that white collar activities associated to higher degrees would protect their jobs from moving abroad. This thesis was a case study of a company offshoring some of its global talent to lower cost locations. The purpose was to understand what factors talent consider in accepting to relocate to a lower cost location under a local contract. This research contributes to talent retention and sustained talent management while offshoring ac-tivities to lower cost countries.

This study focused on independent EFL reading among Grade 11 students across public and non-public schools in Ethiopia. Students who practice independent reading develop a love for reading and ultimately become life-long self-initiated readers. Therefore, independent reading should be considered as a vital goal of instruction and research. The issues of focus in this study were students’ reading comprehension ability levels, attitude towards learning English as a school subject and reading its literature, reading motivation, reading strategy use, persistence in independent reading and access to reading resources along with inclusion of independent reading in classroom instruction and in English textbooks. To this end, the study used quantitative data (collected through reading comprehension test, structured questionnaire and independent reading follow-up checklist) and qualitative data (gathered via classroom observation and content analysis).The findings revealed lower predisposition towards and practice of independent EFL reading among public school students (n = 375). A statistically significant difference, in favour of non-public schools (n = 181), was also found between the two groups of students in scores pertaining to most of the variables investigated. Enhanced scaffolding of independent reading through improved instruction and resource provision, regular short refresher courses for teachers of English and further studies have been recommended to improve public school students’ involvement in independent EFL reading. / English Studies / D. Litt. et Phil. (English Studies)

The researcher of this study " Indian Migrants and Self-Initiated Expatriates in the host Countries: the Focus on Social Support" the whole study about the Indian expatriates who are living in the United Kingdom and the main goal of this research is to predict how successful the Indian expatriates in their settling process in the UK and the focus of social supports. The sample includes both Self-initiated expatriates ( SIE's) and Assigned Expatriates(AE's). SIE's expatriates are Indian students who are studying in the UK and the AE's expatriates are the company assigned Indian full-time employees. Social support includes briefly the overall host country support provided for Indian expatriates in the host country. Social support is measured in three broader dimensions pertinent to Waxin cross-cultural adjustment model (2006), likely perceived organizational support, individual self-motivation, and contextual support, includes family support and host country environment. (Navas et al, 2005) classified six relevant contexts of acculturation of expatriates in a foreign country, which emphasize, politics and government, organizational work-related adjustments, economic perspective, family relations; social relations and ideology, which includes religious belief and customs. The structure of the thesis covers extensive theoretical part based on the intense review of literature in the field of expatriation, cross-cultural studies, information on this context about the United Kingdom and India and final part includes practical data analysis, business cases and recommendation for the future research.