L’interdisciplinarité est désormais inhérente à la recherche scientifique. L’essor des recherches dans le domaine médical a notamment favorisé cette interdisciplinarité. C'est dans ce contexte que s'inscrivent les travaux présentés dans ce manuscrit. En effet, ce dernier vise à la production de nouveaux outils adaptés à des problématiques des sciences de la vie. Ce manuscrit traite de spectroscopie de la fluorescence et de chimie des acides nucléiques. Il est divisé en deux sections : Dans la partie I, nous présentons de nouveaux fluorophores push-pull très brillants, non toxiques et pouvant être utilisé en cultures cellulaires. Ces composés, basés sur des motifs benzothiazoles, peuvent être modulés structurellement afin d'obtenir les propriétés photophysiques souhaitées. D'ailleurs, pour ces composés, une relation structure-propriétés photophysiques a été établie. Ensuite, en utilisant ces fluorophores, nous avons conçu de nouvelles sondes fluorescentes pour suivre l’activité enzymatique de la β-galactosidase. Cette dernière étant un marqueur de la sénéscence cellulaire, nous avons utilisé nos sondes pour détecter la sénescence, in vitro, par des méthodes de microscopie de fluorescence et de cytométrie en flux. La partie II de ce manuscrit est consacrée à la chimie des acides nucléiques. Tout d'abord nous y décrivons la préparation et l'évaluation de nouveaux ligands d’ARN ciblant le domaine IIId de l'IRES du VHC. Ces ligands présentent d'une part, un motif permettant de faire un triplet de base avec la séquence IIId afin d'apporter de la spécificité, et d'autre part, des fonctions aminées afin de stabiliser le triplet par interactions électrostatiques avec les phosphodiesters de IIId. Enfin, la dernière partie concerne le développement d'une nouvelle stratégie permettant la fonctionnalisation post-synthèse d'acides nucléiques en position anomère. Pour ce faire, nous avons conçu des plateformes phosphoramidites qui, une fois incorporées dans des brins oligonucléotidiques, peuvent être impliquées dans diverses réaction de glycosidation. / Interdisciplinary is an obvious feature of scientific research. Notably, the continuously expanding researches in the medical field fostered this interdisciplinarity. Within this context, the work presented here deals with fluorescence spectroscopy and nucleic acid chemistry and aims at providing new tools suited for applications in life sciences. This manuscript presents two sections. In Part I, we developed novel series of highly bright and non-toxic push-pull fluorophores, compatible with cellular applications. In fact, we describe new benzothiazole-based fluorophores that can be structurally modulated to provide dyes with tunable photophysical properties. Their structure-photophysics relationship is also reported. Next, using these fluorophores, we produced new fluorescent probes to monitor the enzymatic activity of the β-galactosidase. Of note, since β-galactosidase is a marker of cellular senescence, we also used our probes for the detection of early stages of cellular senescence using fluorescence microscopy and flow cytometry analysis. Part II of this manuscript is devoted to the chemistry of nucleic acids. First, we describe the preparation and evaluation of novel RNA ligands targeting the IIId domain of the HCV IRES. These ligands can make a base triplet with the IIId sequence to provide specificity, and harbour amino functions to stabilize the triplet by electrostatic interaction with the phosphodiesters of IIId. Finally, the last part concerns the development of a new strategy allowing the post-synthetic functionalization of nucleic acids at the anomeric position. To do this, we designed new phosphoramidite platforms that, once incorporated into oligonucleotide strands, can be involved in various glycosidation reactions.

Les semiconducteurs organiques (OSC) tels que les composés organiques photovoltaïques (OPVs), les diodes électroluminescentes organiques (OLEDs) ou encore les transistors organiques à effet de champ (OFETs) constituent un domaine de recherche très attractif en raison de leur potentiel en tant que couches actives dans les dispositifs optoélectroniques. Les composés aromatiques polycycliques ainsi que les hétéroaromatiques sont considérés comme des matériaux prometteurs pour les OSC en raison de leurs conductivités électriques potentielles, de leurs propriétés optiques ainsi que de leurs assemblages géométriques. Ces deux systèmes et leurs propriétés photophysiques ont été étudiés dans les trois chapitres de cette thèse. Dans le premier chapitre, une étude sur un ensemble d'acènes linéaires, angulaires et condensés consistant en des liens hétéroatomes avec des agrégations uniques a été décrite et analysée. Les hétéroacènes N-fusionnés angulaires et π-étendus sont la classe principale étudiée dans le deuxième chapitre. Leurs synthèses sont basées sur la réaction de couplage de Suzuki-Miyaura et la réaction de Cadogan. Outre les acènes et les hétéroacènes N-fusionnés, les N-hétéroaromatiques ont fait l'objet d'une attention particulière dans le domaine de matériaux. L'un d'entre eux est la classe des quinazolines utilisées comme partie acceptrice d'électrons dans les structures push-pull pour le transfert de charge intramoléculaire (TCI). L'étude des relations entre les structures dérivées du motif quinazoline de type donneur d'électron-accepteur-donneur (D-A-D) et leurs propriétés de photoluminescence est le principal travail mentionné dans le troisième chapitre. / Organic semiconductors (OSCs) are a highly attractive research field due to their potentials as active layers in optoelectronic devices such as organic field-effect transistors (OFETs), organic photovoltaic (OPVs) and organic light emitting diodes (OLEDs). Polycyclic aromatic compounds as well as heteroaromatics are considered as promising materials for OSCs due to their semi conductivity properties, optical properties and geometric structures. The mentioned systems and their photophysical properties were investigated in three chapters of my thesis. In the first chapter, a study on a set of linear, angular and condensed acenes consisting of heteroatom linkages with unique aggregations was described and analyzed. The angular and π-extended N-fused heteroacenes are the main class studied in the second chapter. Their synthesis is based on the Suzuki-Miyaura coupling and the Cadogan reactions. Besides acenes and N-fused heteroacenes, N-heteroaromatics have gained attention in material area. One of them is the quinazoline class that is known as an electron withdrawing unit in push-pull structures for intramolecular charge transfer (ICT). The investigation of the relationships between the electron donor-acceptor-donor (D-A-D) quinazoline-based structures and their photoluminescence properties is the main work mentioned in the third chapter.

Le développement de nouvelles voies synthétiques permettant l’accès à des sondes à applications biologiques connaît un intérêt accru. Les travaux de cette thèse s’inscrivent dans ce cadre. Ils portent particulièrement sur les colorants « Push-pull » qui se caractérisent par leur sensibilité aux changements de leur environnement, leur faible cytotoxicité et leur photostabilité élevée. En outre, la synthèse de ces fluorènes est très exigeante. Nos travaux ont abouti à : 1) Des approches synthétiques concises pour accéder à des composés aromatiques aminés difficiles à synthétiser, celles-ci via des systèmes Pallado-catalysés optimisés impliquant une amination sélective et une synthèse séquentielle en « one pot », 2) La synthèse d'une bibliothèque vaste de fluorènes avec la diversification des groupements accepteur et donneur. 3) Des relations structure- propriétés photophysiques. 4) La synthèse de trois colorants avancés engendrant la première sonde de fluorènes spécifique aux membranes : un outil puissant pour étudier la structure et les dynamiques biophysiques de ces membranes. Le colorant optimal surpasse les caractéristiques des sondes couramment utilisées montrant : une absorption décalée vers le rouge attenant 405 nm en diode laser, une luminosité plus élevée diminuant la concentration du colorant pour la coloration de ~ 10-15 fois, une haute photo-stabilité, une forte sensibilité aux domaines liquides des membranes des cellules. 5) La Synthèse de 4 phosphoramidites marqués et leurs incorporations dans les oligonucléotides attestant une grande sensibilité aux milieux protiques et au pH. En duplex d'ADN, le colorant est efficace pour la différenciation des bases opposées. Une application du marqueur d'ADN fluorescent l’a testé comme un donneur pour le déplacement de Stokes dans une paire de FRET émissive en combinaison avec l’accepteur Dy681. Le FRET a démontré une augmentation ratiométrique dans la région proche infrarouge avec un décalage de 300 nm / Extensive research focuses on finding straightforward synthesis and prospective probes for biological applications. Push-pull dyes are of particular interest for various uses as biosensors for membranes and nucleic acids. These dyes are highly responsive to changes of their environments. Specifically, push-pull fluorenes exhibit low cytotoxicity and high photostability, but are not yet reported in the two mentioned applications. Furthermore, their synthesis is highly demanding. In this context, our work presents: 1) Step-economic and concise approaches to access challenging aminoaromatics via optimized air-stable Pd catalytic systems involving selective mono/di-amination and sequential one-pot synthesis, 2) Synthesis of a fluorene library varying the acceptor and the donor groups, 3) Structure-photophysics relationships, 4) Synthesis of three advanced dyes and concluding the first plasma membrane-specific fluorene probe that can be a powerful tool for studying the structure and biophysical dynamics of membranes. The optimal dye surpasses the features of commonly used probes showing: red-shifted absorption matching the 405 nm diode laser, higher brightness decreasing the dye concentration for staining by ~10-15 folds, high photostability, comparably strong sensitivity to liquid domains of cell membrane, and 5) Synthesis of 4 fluorene-labeled phosphoramidites and their site-specific ODN incorporations evidencing high sensitivity to protic media and pH. Labeled sequences exhibited a far-red emission with modest quantum yields in line with their strong charge transfer character. In DNA duplexes, the dye efficiently base-discriminated opposite cytidine and thymidine. A preliminary application of the DNA fluorescent marker involved testing it as a mega-Stokes shift donor in an emissive FRET pair in combination with Dy681 acceptor. The FRET demonstrated a ratiometric turn-on in NIR region with a shift of 300 nm

An important event in people´s lives is graduating from high school, which opens new possibilities. One of them is to be able to move to a new place, whether it is within the same municipality, to another region or even another country. Several motives can affect the decision-making process in terms of where the individual chooses to move and why. The aim of this paper is to study these motives and how a decision can be explained with Weber’s social action theory and the push/pull-theory   The method used to investigate this subject is a survey study in terms of a questionnaire with high school students in Luleå municipality. The answers were thereafter analyzed in two parts. The first part by using quantitative methods to create statistics regarding the chosen population, how they rank different motives and their opinions regarding different factors. The second part of the questionnaire was analyzed with qualitative methods to investigate the answers on a more complex level since different factors are taken into account in the reasoning behind a decision.   The result of this study shows that the main motive for moving is further education and the main motive to stay is social motives like family and friends. Other motives also come into play in this complex decision making process, such as a change of environment to experience new things. Where and why people choose to move can also be explained by push/pull-factors where the current condition in Luleå municipality is fairly good concerning employment and education but does not have the program or courses they want to study at the university and this functions as a push-factor for some in the studied group. Family and friends function as the main pull-factor to stay and is sometimes given as the only motive to stay. Where they want to move is mainly metropolitan areas or larger cities in the south of Sweden with the given explanation that this would offer more possibilities with a wider range of higher education, meeting new friends, access to more entertainment and experiencing city life. This decision can also be explained by the social action theory regarding how the individual chooses to act and it is usually based on the goal-oriented type where the individual chooses to move to reach a set goal.

This qualitative research project focused on the interviews of 27 low socio-economic students at a research university in the southwestern United States. The students had already withdrawn from the university or were in the process of withdrawing. The study seeks to provide increased understanding of how students negotiate the decision-making process to withdraw from the first university they attended after high school. The theoretical lenses of student departure theories (Astin, 1993; Bean, 1983; Tierney, 1992; and Tinto, 1993) and decision-making theories (Becker, 1976; Frank, 1987; Kahneman, 2003; March, 1994; Scott, 2000) were combined. The Decision-Making Process Model of Student Departure is offered as a new theoretical framework that combines decision-making theories and student retention theories. This conceptualization is unlike other student departure models because it includes the proposition that forces push at the student from within the institution and forces pull them from outside the institution. In addition, it is different from other student departure models because it includes the discussion about how students think about their process to withdraw - it is not meant to describe their behaviors. Financial, academic and psychological stresses (from both within and outside the institution) influenced how the students negotiated the decision-making process to leave the institution. The students did not seek out institutional agents (advisors or faculty members) for advice when they were struggling academically. They developed their own strategies or went to their family members for advice, many of whom had never been to college.

The explosive demand for multimedia and fast transmission of continuous media on wireless networks means the simultaneous existence of traffic requiring different qualities of service (QoS). In this thesis, several efficient algorithms have been developed which offer several QoS to the end-user. We first look at a request TDMA/CDMA protocol for supporting wireless multimedia traffic, where CDMA is laid over TDMA. Then we look at a hybrid push-pull algorithm for wireless networks, and present a generalized performance analysis of the proposed protocol. Some of the QoS factors considered include customer retrial rates due to user impatience and system timeouts and different levels of priority and weights for mobile hosts. We have also looked at how customer impatience and system timeouts affect the QoS provided by several queuing and scheduling schemes such as FIFO, priority, weighted fair queuing, and the application of the stretch-optimal algorithm to scheduling.

The UK has been amongst the leaders in providing higher education for both home and international students, especially from developing countries such as Malaysia. The recent budget cuts on the UK higher education sector implemented in the academic year 2012/13 have increased the competition for UK Higher Education Institutions (HEIs) to secure home [UK and EU] students as the opportunity cost is greater compared to starting a career. Therefore, it is almost imperative for UK HEIs to attract more international students to fill the gap left by home students to remain financially sustainable. Previous researches on the decision making process for higher education destinations looked extensively at rational factors such as financial viability, size of institutions and availability of programmes as well as reputation related factors, such as university ranking and league tables. The question is: Are these the factors - rational factors - that influence the decision making of prospective international students' evaluation and selection of the UK as a possible host country for higher education migration? This research aims to elicit and understand the non-rational factors that may intrinsically influence the decision making behaviour of Malaysian students when selecting the UK as the destination for HE migration. Interpretive phenomenology was utilized as the research approach and the Ethnographic principle of cultural interpretation was enhanced by the researcher's reflexive stances. Data was analysed using Interpretative Phenomenological Analysis. Six emergent constructs were revealed which then led to the emergence of three core themes reflecting the intrinsic influences hidden within Malaysian students' HE migration decision behaviour. Twelve ZMET interviews and two focus group conversations with participants whom were recruited using the stratified random sampling method - covering three geographical regions of the UK, eleven UK universities within four main university groups. ZMET, short for Zaltman Metaphor Elicitation Technique, is an eleven-step in-depth interview technique that elicits both conscious and unconscious thoughts by exploring metaphoric expressions. Findings from previous researches employing ZMET as data collection method showed that data saturation is achievable with just four to five interviews, providing 90% validity. Focus group conversations functioned as methodology triangulation to validate findings. Both of these data collection methods were guided by two overarching questions: (1) why do you choose a UK university? and (2) what and how does being a UK university student make you feel? The six emergent constructs: (1) Egotism; (2) Self-concept; (3) Current security; (4) Future security; (5) Freedom and independence; and (6) Future opportunities, were then interpreted through the researcher's reflexive stances - personal and epistemic - to signify the insights of the three emergent themes: (1) Fulfilling their emotional needs for acceptance; (2) Satisfying their spiritual pleas for freedom and independence; and (3) Providing a promise for a greater self-worth. These six emergent constructs were embedded into the conceptual framework of this research - Consumer Decision Making model underpinned by Push/Pull Theory of Migration - resulting in a revised conceptual framework depicting Malaysian students' HE migration behaviour. This research contributes to academic knowledge, research methodology, practitioners and policy makers of HEIs - both in Malaysia and the UK. Suggestions for further research are longitudinal study, geographical extension study, comparison study and a study using this research's revised conceptual framework as the research model.

Despite research focused on the control of E. saccharina Walker (Lepidoptera: Pyralidae), it remains the most destructive pest of sugarcane in South Africa and therefore a shift in the approach to the control of this insect was required. Habitat management techniques were employed through trials to understand the mechanisms used by insect pests in their host plant oviposition behaviour. Indigenous and beneficial non-crop plants, which could be used to attract insect pests away from sugarcane were identified and tested. An African grass, Melinis minutiflora, shown to be repellent to lepidopteran stemboring pests, was used in field trials in sugarcane. Eldana saccharina was shown to be fairly indiscrimate in choosing host plant species. Oviposition trials showed that females made no choice for host plants oviposition based on the volatiles released by those plants. Females showed no preference for males over test plants. But did consistently move and make a plant choice more often than male moths. Moths were not attracted by the volatile stimuli of a host plant and the availability of cryptic sites might be a factor that influenced ovipositing females to choose a host plant. Field trials tested the repellent action of Melinis minutiflora against E. saccharina and were shown to be more effective over a big field with space for M. minutiflora to establish thick undergrowth alongside a field plot. The other field sites showed no significant effect from M. minutiflora intercropped into treatment plots, or a slight negative effect. Later sugarcane planting times in relation to the grass planting time was a possible reason for the positive result in only two field sites allowing the grass to grow and establish before the sugarcane competed with the grass for sunlight. A cost benefit analysis of planting a hectare of sugarcane with M. minutiflora showed an economic benefit linked to reduction in E. saccharina infestation. Field sites with low population pressure from E. saccharina would not yield the economic benefit of planting this grass. There was no significant loss in the height, density or sucrose yield (ERC% cane) between control and treatment plots in the field plots due to the presence of M. minutiflora. Comparison of weed biomass between treatment and control plots showed a significant reduction in the treatment plot where M. minutiflora out-competed the weeds already present. This grass was advantageous in the sugarcane field as it sometimes reduced moth infestation but did not significantly compete with sugarcane and showed weed suppressing potential.

This study is concerned with the development of a method for creating shapes and form in clothing with minimum exertion on the cloth, using simple construction techniques. It is an exploration of an approach to producing clothing in a less familiar manner to the usual way of working which involves, almost always, drafting or flat-pattern making. With the expression of the movement of the textile around the body as the main aim, the ‘push/pull’ principle is employed to direct its flow in both a symmetric and asymmetric fashion. It is a principle inspired by Madame Gres, the French designer of the 1930s to 1980s, famous for her neo-classic inspired gowns. The textile, usually a rectangle, is manipulated without cutting into it but by pushing and pulling first, through the upper limbs of the body, and then ‘worked’ around the rest of the body, using draping and pleating to create shapes which are spontaneous, elaborate and not pre-determined. Furthermore, the approach explores the aesthetic potential of draping and combining the Filter 80 PPI, an industrial textile used for filtering, with conventional clothing materials, linen and/or cotton in this case. The parallels and constasts of this mix are noted, together with the distinct expressions, which nonetheless both display a simple approach in construction, minimal manipulation of the textile, the use of the upper limbs as natural obstacles, and the ‘no-cut’ principle of the rectangular piece of cloth. With free form construction and reflection, one discovers expressions possible only through the use of an experimental approach in working. / Program: Master Programme in Fashion and Textile Design

The purpose of Understanding Why International Student Applicants Choose a Public Four-Year Institution was to apply a mixed-methods research approach to California State University, San Bernardino’s (CSUSB) international student population to better understand the factors associated with an international student’s decision-making processing to study abroad. Internationalization by institutions reflects the current two million international students studying around the world. In recent years internationalization has become more of an economic driving force, whereas in the past it was an opportunity for diversifying knowledge and research. Studies on push and pull factors reflect reasons why international students have decided to go abroad. Factors range from lack of access at home institutions for various programs to the desire to learn about Western culture. Seeing as the population of these studies is so diverse ethnically and culturally, it is important to be mindful of the various forms of capital students possess as an international student and the uniqueness this brings to each students experience. A questionnaire was utilized to gather quantitative data to provide descriptive statistics of the population, and interviews were conducted with participants to acquire the rich stories. The questionnaire submissions resulted in 52 returned surveys for a response rate of five percent. Six interviews were conducted, which provided a diverse group of international student representation for the analysis of the rich text allowing for a strong understanding of this specific case study. Based on the interviews conducted, responses reflected many of those that previous studies found. All but one interviewee mentioned the costs of attending as a deciding factor. Reputation of the institution and prestige of a US degree were also factors mentioned by the majority of participants. Both participants from African countries mentioned a lack of program availability as a reason to go abroad, while both Indian participants mentioned the desire to work after graduating for experience before returning home. Interestingly, most participants mentioned a connected family member to either the institution itself or the state of California as a reason for choosing CSUSB. The data that were collected for the purposes of this study did show some correlation to previous studies findings. The qualitative data proved useful in better understanding the needs of specific students, while also alluding to potential geographic considerations that need to be had when recruiting abroad and meeting the needs of international students around the world.