Les protéines jouent un rôle important dans les cellules, via leur activité enzymatique et les interactions qu’elles mettent en jeu. Ces fonctions sont principalement basées sur la structure des protéines. Afin de détecter leur présence, et de caractériser leur structure, nous nous sommes appuyés sur les propriétés optiques des nanostructures. La résonance des plasmons de surface localisés (RPSL), ainsi que la diffusion Raman exaltée de surface(DRES), nous ont permis de détecter différentes protéines. Une optimisation des nanostructures nous a également permis de concevoir un biocapteur basé sur la DRES, qui soit sensible, reproductible et spécifique. En effet, la détection spécifique d’un biomarqueur pathologique, la protéine Manganèse Super Oxide Dismutase (MnSOD), a été réalisée grâce à l’utilisation de nanostructures optimisées et fonctionnalisées avec un aptamère (séquence ADN). Avec ce système, nous avons démontré la détection de la MnSOD à des concentrations physiologiques dans des fluides corporels comme le sérum et la salive. Enfin, l’étude de la structure de la protéine Spleen Tyrosine kinase (Syk), par DRES, nous a permis de mettre en évidence un réarrangement structurale de Syk lors de sa phosphorylation. Une étude complémentaire par Western Blot montre que son activité kinase est dépendante de son état de phosphorylation indiquant que la structure et l’activité de Syk sont liées. L’ensemble de ces travaux contribue à une meilleure connaissance de l’interface entre la physique et la biologie. / Proteins play an important role in cells via their enzymatic activity and the irinteractions. Their functions are mainly based on the protein structure. In order to detect their presence and to characterize their structure, we used optical properties of nanostructures. The localized surface plasmon resonance (LSPR), as well as the surface enhanced Raman scattering (SERS), allowed us to detect various proteins. We also optimized nanostructures to build a sensitive, reproducible and specific biosensor based on SERS. Indeed, specific detection of one pathological biomarker, the Manganese Super Oxide Dismutase (MnSOD) protein, was investigated by using optically optimized and aptamer-functionalized nanostructures. Using this system, we were able to detect the MnSOD at physiological concentration in body fluids, such as serum and saliva. Finally, the structural study of the Spleen Tyrosine kinase (Syk) protein by SERS, allowed us to demonstrate that its structure varied with its phosphorylation levels. A complementary Western Blot analysis showed that the Syk kinase activity depended also on its phosphorylation state, meaning that the structure and the activity of Syk were linked. Altogether, these data contributed to a better understanding of the interface between physics and biology.

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The competition on the business market is constantly growing among entrepreneurial organizations. Competitive advantages and strategies is a must in order to survive the environmental triggers of change. One of those strategies is to increase the entrepreneurial activity. However, entrepreneurial adaption is a phenomenon that is represented by continuous change. It is rather an on-going strategy for organizations than a conclusion or a settling point. The entrepreneurial activity needs to flourish through the whole organization i.e. in the people, groups and hierarchical levels. Therefore, other organizational elements affect in how successful an organization can operate in an entrepreneurial way. Organizational structure is one of those elements, which not only lay the foundation for the operation but also affect other organizational factors. Hence, organizations require the knowledge on which factors that can impact the entrepreneurial activity, before it is even essential to change the strategies. This qualitative research aims to gain knowledge in how organizational structure affects the entrepreneurial orientation. Three different dimensions, of both organizational structure and entrepreneurial orientation, are going to be acknowledged in order to measure the elements and find a relation between them. This will not just enhance the understanding of the area, but also fulfil the thesis purpose and research question. The focus of the study lies within one large entrepreneurial organization, namely Scandic Hotels that operate in an industry with an immense competition, which do not possesses the most evident entrepreneurial business market. The empirical findings are based on semi-structured interviews, which will be analysed in conjunction with the theoretical frame of references. Further, the empirical findings are thus used to analyse the research results to then answer the purpose of this thesis. The study showed that the organizational structure at Scandic Hotels is represented by high complexity, formalization and centralization. Besides that, the main structural approach is that the operation is run by a concept driven strategy. Through the analysis it was shown that these findings affected the entrepreneurial orientation within the organization. The entrepreneurial dimensions of innovation, proactiveness and risk- taking proved degrees that were considerably lower. On this basis, the study finds that organizational structure has an impact on entrepreneurial orientation. The relation between the dimensions is highly complex and not a clear line i.e. they all affect each other in some matter. However, a structural change is difficult for a large organization as Scandic Hotels. But there are structural strategies that can be made to increase the entrepreneurial orientation through the whole organization. / Entrepreneurial orientation

L’objectif principal de cette thèse est d’étudier l’évolution des clusters. La littérature concernant les clusters s’est longuement intéressée aux raisons de leur existence ainsi qu’à la manière dont ils favorisent l’innovation, la productivité et la croissance. Nous étudions comment ces effets durent dans le temps, poursuivant l’objectif d’identifier les déterminants de la performance dynamique des clusters. Il s’agit, ainsi, d’expliquer pourquoi certains clusters déclinent tandis que d’autres continuent à fonctionner grâce à un renouveau constant. Cette thèse adopte une approche des clusters par les réseaux. Nous défendons l’idée que les structures de réseau hétérogènes des clusters démontrent des capacités différentes à s’associer ou à se dissocier des cycles industriels/technologiques au bon moment. Ainsi, nous identifions les propriétés de structure du réseau qui favorisent la performance dynamique des clusters ou la résilience des clusters. Nous appuyons nos développements théoriques sur des regards empiriques dans deux contextes bien différents. D’une part, nous étudions les structures des clusters de l’industrie de la téléphonie mobile en Europe. D’autre part, nous analysons la structure des relations entre les producteurs de fromage d’Aculco (Mexique). Le résultat principal de ce travail montre que la hiérarchie et la disassortativité des réseaux, ainsi que les interactions entre des réseaux de natures différentes (multiplexité), influencent la capacité des clusters à éviter les lock-in négatifs, conduisant à leur déclin, et favorisent le lock-out pour la survie du cluster, c’est-à-dire la prolongation de leur vie. / The main objective of this thesis is to study clusters’ evolution. The literature on clusters has widely studied why clusters exist and how they favor innovation, productivity and growth. Our concern is to study how these effects hold over time. Therefore, we aim at identifying the determinants of dynamic performance of clusters to explain why some clusters decline while others keep working by continuous renewal. To do so, this thesis approaches clusters from a network perspective. We contend that clusters with heterogeneous network structures exhibit different capacities to associate and dissociate cluster’s evolution and industrial/technological cycle at the right moment. Thus, we identify the properties of network structures that favor dynamic performance of clusters or cluster resilience. We support our theoretical developments with empirical insights in two different contexts. On the one hand, we study the structure of clusters in the European mobile phone industry. On the other hand, we analyze the structure of relations between cheese producers in Aculco (Mexico). The main result of this work is that network hierarchy, network disassortativity and the interplay between different networks (multiplexity) influence the capacity of clusters to avoid negative lock-in leading to cluster failure, and favor lock-out to enhance cluster continuation, i.e. extending the life of the cluster.

This thesis presents a spectroscopic and computational study of a variety of substituted oligothiophenes. The purpose of this study was to elucidate the structural properties of their neutral, oxidised and excited states. This was accomplished using a number of spectroscopic methods, including electronic absorption, resonance Raman and fluorescence spectroscopy. Analysis of the data provided by these methods was aided by the application of density functional theory (DFT) to the neutral and charged species, allowing conclusions regarding bond length changes and molecular orbitals to be drawn. Advancing the understanding of the structural properties of conductive materials such as oligothiophenes is important due to their potential application in plastic electronic devices (organic solar cells, field effect transistors and light emitting diodes, for instance) and the need to clarify the charge transport mechanism. The compounds examined in this thesis are primarily based on 3� styryl-substituted terthiophene. Substituted derivatives of this molecule include those with groups on the para position of the phenyl ring or methyl α,α� end caps. Larger ethenyl-aryl groups were also investigated, as were analogous thiophenes and sexithiophenes. Indeed, the 3�-substituted sexithiophenes formed an integral part of this investigation since they rapidly form in the head-to-head orientation from the oxidation and consequent [sigma]-dimerisation of the substituted terthiophenes. DFT calculations on the sexithiophene charged species have indicated the presence of a full polaronic or bipolaronic structural defect in the centre of the thiophene backbone, as defined by the reversal of the CC bond length alternation to create a domain of quinoidal bond sequence. However, the structural defect of the styryl sexithiophenes is more strongly localised than that observed for unsubstituted sexithiophene; indeed, the charged defect appears to be confined by the positions of the styryl substituents. This defect confinement along the thiophene backbone is particularly apparent in the styryl sexithiophene dications. Electronic absorption and resonance Raman spectroscopy have been applied to the oxidation products of the styryl terthiophenes. Only sexithiophene charged species are observed when the α termini are unsubstituted; these include sexithiophene radical cations, [pi]-dimers (a stabilising face-to-face interaction between two radical cations) and dications. The resonance Raman spectra of these charged species are characterised by a very intense symmetrical CC stretching mode of the thiophene inter-ring bonds, which is also evident in the theoretical spectra. The extensive differences between the styryl and unsubstituted sexithiophene dication Raman spectra have been attributed to defect confinement: the strongest Raman band of the unsubstituted sexithiophene dication is due to a vibrational mode localised over the entire sexithiophene backbone while that of the styryl sexithiophenes is localised over the central two thiophene rings - the same area occupied by the confined defect. A combined steady-state and picosecond time-resolved emission study on the styryl terthiophenes revealed that by judicious choice of the para R group in styryl terthiophenes it is possible to tune the nature of the first excited singlet state from [pi],[pi]* to charge transfer character. Charge transfer states may offer possible strategies for solar cells in which charge separation is a key step.

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