Dans ce travail de thèse, nous avons étudié des effets d'optique non-linéaire d'ordre trois dans les cavités à cristaux photoniques en silicium. Le premier d'entre eux est un phénomène d'auto-oscillations à haute fréquence (GHz) dans ces cavités, qui a pour origine une modulation de la transmission de la cavité due à l'interaction entre la dispersion due aux porteurs libres et l’absorption à deux photons. Nous avons observé ces auto-oscillations, pour la première fois, dans les nanocavités à cristaux photoniques silicium avec une fréquence de l’ordre de 3 GHz et une grande pureté spectrale. Nous avons développé un modèle pour analyser les mécanismes qui régissent l'apparition de ces auto-oscillations, ainsi que les amplitudes des fréquences fondamentale et harmoniques de ces oscillations. Ce phénomène d'auto-oscillations permettrait de réaliser des sources micro-ondes en silicium très compactes. Le deuxième phénomène étudié est celui de la diffusion Raman, qui est le seul moyen d'obtenir des lasers entièrement en silicium démontré jusqu'à présent. Cette diffusion Raman a été mesurée tout d'abord dans des guides d'onde à cristaux photoniques étroits (W0.63) de longueur 100 microns, où nous avons pu obtenir un nombre de photons Stokes allant jusqu'à 9, montrant ainsi que la diffusion Raman stimulée prédominait dans ces guides d'onde, bien que nous n’ayons pas pu y obtenir un effet laser Raman franc. Nous avons ensuite mesuré la diffusion Raman dans des nanocavités doublement résonantes conçues spécifiquement à partir de ces guides d'ondes pour optimiser l'effet Raman, avec des facteurs de qualités allant jusqu'à 235000 pour la résonance Stokes. Bien que nous n'ayons pu mesurer que de la diffusion Raman spontanée dans ces cavités, avec un facteur de Purcell de 2.9, l'étude théorique que nous avons effectuée sur les lasers Raman, et qui s'accorde parfaitement avec les résultats expérimentaux, montre qu’il serait possible d'obtenir un laser Raman dans ces cavités avec un seuil en dessous du milliwatt à condition de diminuer ces pertes dues à l'absorption par porteurs libres. Ceci pourrait être accompli en diminuant le temps de vie des porteurs libres, par exemple en les retirant du silicium à l’aide d’une jonction MSM. / In this thesis, we studied third order nonlinear optical effects in photonic crystal cavities. The first of those effects is is the phenomenon of high frequency (GHz) self-pulsing in these cavities, which originates from a modulation of the transmission of the cavity due to the interaction between the free-carrier dispersion and the two-photon absorption. We have observed these self-induced oscillations for the first time in silicon photonic crystal nanocavities, with a frequency of about 3 GHz and a high spectral purity. We have developed a model to analyze the mechanisms that govern the onset of these oscillations, as well as the amplitudes of the fundamental and harmonic frequencies of these oscillations. This self-pulsing phenomenon would allow us to realize realize ultra-compact microwave sources made of silicon. The second phenomenon studied is that of Raman scattering, which is the only way to obtain lasers fully in silicon demonstrated so far. The Raman scattering was measured first in narrow photonic crystals waveguides (W0.63) of length 100 microns, where we could obtain a number of Stokes photons up to 9, showing that the stimulated Raman scattering predominated in these waveguides, although we have not been able to obtain a true Raman laser effect in them. We then measured the Raman scattering in doubly resonant nanocavities specifically designed from these waveguides to optimize the Raman effect, with quality factors up to 235000 for the Stokes resonance. Although we could only measure spontaneous Raman scattering in these cavities, with a Purcell factor of 2.9, the theoretical study that we conducted on the Raman lasers, which agrees perfectly with the experimental results, shows that it would be possible to obtain a Raman laser in these cavities with a threshold below the milliwatt, provided we reduce the losses due to the free-carrier absorption. This could be accomplished by decreasing the free-carrier lifetime, for example by removing the free carriers from the silicon using a MSM junction.

Gene transfer techniques such as retroviral transduction have many applications such as cell marking, cell reprogramming, and therapeutics. Transgene expression, however, is often variable and maintaining long-term expression is problematic in progenitor cell types. To better control transgene expression, research has focused on the optimized use of cis-regulatory elements, such as promoters, enhancers and insulators. In addition to controlling gene expression, these regulatory elements modulate the nuclear organization of the transgene. The integration site also exerts significant effects on steady state and temporal transgene expression via the neighbouring chromatin environment. The first part of this thesis describes the co-operation of modified β-globin intronic elements in providing high-level expression and favorable nuclear localization. I demonstrate that these elements are compatible with efficient lentivirus transduction for globin gene therapy purposes. In the second chapter, I examine high-expressing EGFP retroviral transgenes and show that such steady state expression may exhibit rapid transcriptional fluctuations, which is modulated by different transcriptional dynamics at different integration sites. Finally, in the last chapter, I evaluate the use of a 3’D4Z4 insulator element in maintaining long-term EGFP transgene expression in ES cells, and discover integration-site specific temporal dynamics in retroviral vector expression. Overall, my results demonstrate that using multiple regulatory elements and insulating these elements from different types of genomic loci optimize transgene expression and dynamics in progenitor cells.

Gene transfer techniques such as retroviral transduction have many applications such as cell marking, cell reprogramming, and therapeutics. Transgene expression, however, is often variable and maintaining long-term expression is problematic in progenitor cell types. To better control transgene expression, research has focused on the optimized use of cis-regulatory elements, such as promoters, enhancers and insulators. In addition to controlling gene expression, these regulatory elements modulate the nuclear organization of the transgene. The integration site also exerts significant effects on steady state and temporal transgene expression via the neighbouring chromatin environment. The first part of this thesis describes the co-operation of modified β-globin intronic elements in providing high-level expression and favorable nuclear localization. I demonstrate that these elements are compatible with efficient lentivirus transduction for globin gene therapy purposes. In the second chapter, I examine high-expressing EGFP retroviral transgenes and show that such steady state expression may exhibit rapid transcriptional fluctuations, which is modulated by different transcriptional dynamics at different integration sites. Finally, in the last chapter, I evaluate the use of a 3’D4Z4 insulator element in maintaining long-term EGFP transgene expression in ES cells, and discover integration-site specific temporal dynamics in retroviral vector expression. Overall, my results demonstrate that using multiple regulatory elements and insulating these elements from different types of genomic loci optimize transgene expression and dynamics in progenitor cells.

Resumo: Gerbera jamesonii Bolus é uma espécie da família Compositae. O capítulo, com diâmetro de 8 - 14 cm, possui flores liguladas de cores vivas organizadas ao redor do centro, que contém os botões florais. Esta inflorescência é sustentada por uma haste longa e sem folhas. Atualmente é uma das dez flores mais comercializadas no Brasil e está entre as três principais flores de corte. A utilização de soluções conservantes, tratamentos de "pulsing", ou fortalecimento, e baixas temperaturas de armazenamento visa prolongar a vida e manter por mais tempo a qualidade das flores cortadas. Neste contexto, este trabalho teve por objetivos avaliar o efeito de diferentes práticas de manejo na pós-colheita sobre a fisiologia e conservação de inflorescências de gérberas. Para os quatro primeiro experimentos foi utilizada a gérbera cv. Suzanne, de coloração laranja. Os experimentos foram conduzidos em delineamento inteiramente casualizado, em esquema fatorial. No primeiro experimento, as inflorescências permaneceram nas seguintes soluções de manutenção: 1) Água destilada; 2) Cloro a 100 mg.L-1; 3) 8-hidroxiquinolina (8-HQC) a 100 mg.L-1; 4) 8-HQC a 200 mg.L-1; e 5) 8- HQC a 400 mg.L-1, cujas hastes foram mantidas em condição controlada de laboratório (20°C; 70% UR). Este experimento possibilitou observar danos nas bases das hastes, causados pelos tratamentos com cloro a 100 mg.L-1 e com as doses mais elevadas de 8-HQC. A manutenção da boa qualidade foi observada no tratamento com 8-HQC a 200 mg.L-1. A longevidade média foi de 12 dias em vaso. No segundo experimento foram utilizadas, durante o armazenamento a 20°C e 70% UR, as soluções: 1) Água destilada; 2) Ácido cítrico a 64 g.L-1; 3) Cloro a 25 mg.L-1 4) Cloro a 50 mg.L-1 5) 8-HQC a 25 mg.L- 1 e 6) 8-HQC a 50 mg.L-1. Com os resultados verificou-se a baixa eficiência do... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Gerbera jamesonii belongs to the Compositae family. The inflorescence, with diameter of 8 - 14 cm, is a capitulum with ligules with vivid color organized around de center, that contain flower buds, which can be in a variety of colors. This colorful flower is supported by a long stem, without leaves. Nowadays it is one of the ten most commercialized flowers in Brazil and is one of the three main cut flowers. The use of keeping-quality solutions, pulsing treatments and low temperature during the vase life seeks to prolong vase life and to maintain the quality of cut flowers. In this context, this research was conducted, at FCAV-UNESP, Jaboticabal, SP, Brazil, to evaluate the effects of several handling techniques on postharvest physiology gerbera cut flowers. The experiments followed complete randomized design, in factorial arrangement. On the first one, the inflorescences remained in the following solutions: 1) Distilled water; 2) Chlorine at 100 mg.L-1; 3) 8-hydroxyquinolin (8-HQC) at 100 mg.L-1; 4) 8-HQC at 200 mg.L-1; and 5) 8-HQC at 400 mg.L-1, which the stems remained in environmental conditions (20°C; 70% RH). On this experiment, it was possible to observe the damage caused by the treatments using chlorine at 100 mg.L-1 and high dosage of 8-HQC. The good quality where kept by using 8-HQC at 200 mg.L-1 and the average longevity of the experiment was 12 days. On the second experiment, the gerberas remained, during storage, in the following solutions: 1) Distilled water; 2) Citric acid at 64 g.L-1; 3) Chlorine at 25 mg.L-14) Chlorine at 50 mg.L-1; 5) 8-HQC at 25 mg.L-1 ; and 6) 8-HQC at 50 mg.L-1. With the results it was possible to verify the low efficiency of the citric acid at the used concentration and the lower damage by lower concentrations of chlorine and 8-HQC than the usually recommended, which kept the good quality of the flowers for... (Complete abstract, click electronic access below) / Orientador: Ben-Hur Mattiuz / Coorientadora: Teresinha de Jesus Deléo Rodrigues / Banca: Regina Maria Monteiro de Castilho / Banca: Carlos Eduardo Ferreira de Castro / Banca: Káthia Fernandes Lopes Pivetta / Banca: Pedro Luís da Costa Aguiar Alves / Doutor

Transcription has turned out to be a discontinuous process when imaged at a single cell level. This observation is referred to as transcriptional bursting or pulsing and has been detected in a variety of organisms ranging from bacteria to mammalian cells. The dynamics of transcriptional pulsing are influenced by the properties intrinsic to the transcriptional process, as well as by upstream factors: chromatin environment, signalling molecules, cell cycle stage etc. In the first part of this thesis, we focused on the regulation of transcriptional pulsing in the nucleolus. Using imaging of living cells, we detected pulsatile transcription of a transgene with nucleolar localization whose expression was mediated by RNA polymerase II. In the second part of the thesis, we investigated the relationship between chromatin decondensation and transcriptional dynamics. We used hyperosmotic medium to induce global condensation of chromatin and revealed that upon chromatin decondensation, a transient spike in transcriptional intensity occurs in induvial living cells. Next, we analysed expression of TFRC and POLR2A genes in several cell cycle stages using single molecule RNA FISH. We detected increase in both frequency and size of transcriptional pulses during a limited time window which coincided with chromatin...

This is a project-based thesis focusing on the investigation of topics related to human newborns and the factors found in their surrounding environment that need to be assessed so as to provide them with a feeling comfort. The objective is to boost their emotional development by the means of light in a close relation to sound so as to provide them with a type of intelligence allowing them to normally interact within a society during their adult life, reassuring social equality and eliminating potential social exclusion due to unexpected behaviours. After researching topics to have a better understanding of the newborn baby and its enclosing environment, a luminaire design solution -functioning with a reactive scheme performed with integrated sound sensors- provided further results to the main topic investigation. The conceptual scheme for the product development was inspired by the connection between the newborn and their life-giver, closely linked to the cross-modality of sensory development before and after birth. Additional results were obtained with light measurement assessments and a parent survey targeting both the intended light quality subjective evaluations and the marketing strength of the designed product. This survey was used -along with other means- as a design evaluation tool at the final stage of the design process. Potential further improvements as well as considerations for a distinct spatial application are discussed in the final part of the thesis. The sustainability aspect covered within this degree project is closely linked to good physical and mental health aspects, clean energy use and efficiency achieved by the integration of input sound sensors and controls, and conscious production and consumption by the proposal of low global footprint materials for the luminaire design. In the conclusions, an overall summary of the thesis outcomes is presented and further research is proposed regarding both the main topic investigation as well as a greater user category that can be related to the light metric assessments that were carried out for this research.

No abstract provided. / Thesis / Master of Engineering (MEngr) / Scope and contents: This thesis describes the behaviour of iron ore-water suspensions under turbulent flow conditions. This work is divided into two parts. Part I deals with the regimes of transport under steady state flow conditions in circular and horizontal ducts. The heterogeneous flow regime is extensively analyzed; a sequential discrimination of models with an oriented design of experiments have permitted the determination of the best model to correlate hydraulic gradients for these suspensions. A critical discussion on the limit deposit conditions is also included. Part II describes the behaviour of clear water under oscillatory flow conditions. The study demonstrates that the quasi-steady state hypothesis, i.e., fully developed flow assumption, applied to pulsatile turbulent flow under the conditions studied. Observations on the behaviour of iron ore-water suspensions under pulsatile flow are also included. The experiments were carried out using a new air-pulsing technique.

No description available.

Made available in DSpace on 2014-06-11T19:33:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-29Bitstream added on 2014-06-13T20:25:30Z : No. of bitstreams: 1 durigan_mfb_dr_jabo.pdf: 3249388 bytes, checksum: 9f67b354f51854cbee43a06c30c8f27a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Gerbera jamesonii Bolus é uma espécie da família Compositae. O capítulo, com diâmetro de 8 – 14 cm, possui flores liguladas de cores vivas organizadas ao redor do centro, que contém os botões florais. Esta inflorescência é sustentada por uma haste longa e sem folhas. Atualmente é uma das dez flores mais comercializadas no Brasil e está entre as três principais flores de corte. A utilização de soluções conservantes, tratamentos de “pulsing”, ou fortalecimento, e baixas temperaturas de armazenamento visa prolongar a vida e manter por mais tempo a qualidade das flores cortadas. Neste contexto, este trabalho teve por objetivos avaliar o efeito de diferentes práticas de manejo na pós-colheita sobre a fisiologia e conservação de inflorescências de gérberas. Para os quatro primeiro experimentos foi utilizada a gérbera cv. Suzanne, de coloração laranja. Os experimentos foram conduzidos em delineamento inteiramente casualizado, em esquema fatorial. No primeiro experimento, as inflorescências permaneceram nas seguintes soluções de manutenção: 1) Água destilada; 2) Cloro a 100 mg.L-1; 3) 8-hidroxiquinolina (8-HQC) a 100 mg.L-1; 4) 8-HQC a 200 mg.L-1; e 5) 8- HQC a 400 mg.L-1, cujas hastes foram mantidas em condição controlada de laboratório (20°C; 70% UR). Este experimento possibilitou observar danos nas bases das hastes, causados pelos tratamentos com cloro a 100 mg.L-1 e com as doses mais elevadas de 8-HQC. A manutenção da boa qualidade foi observada no tratamento com 8-HQC a 200 mg.L-1. A longevidade média foi de 12 dias em vaso. No segundo experimento foram utilizadas, durante o armazenamento a 20°C e 70% UR, as soluções: 1) Água destilada; 2) Ácido cítrico a 64 g.L-1; 3) Cloro a 25 mg.L-1 4) Cloro a 50 mg.L-1 5) 8-HQC a 25 mg.L- 1 e 6) 8-HQC a 50 mg.L-1. Com os resultados verificou-se a baixa eficiência do... / Gerbera jamesonii belongs to the Compositae family. The inflorescence, with diameter of 8 – 14 cm, is a capitulum with ligules with vivid color organized around de center, that contain flower buds, which can be in a variety of colors. This colorful flower is supported by a long stem, without leaves. Nowadays it is one of the ten most commercialized flowers in Brazil and is one of the three main cut flowers. The use of keeping-quality solutions, pulsing treatments and low temperature during the vase life seeks to prolong vase life and to maintain the quality of cut flowers. In this context, this research was conducted, at FCAV-UNESP, Jaboticabal, SP, Brazil, to evaluate the effects of several handling techniques on postharvest physiology gerbera cut flowers. The experiments followed complete randomized design, in factorial arrangement. On the first one, the inflorescences remained in the following solutions: 1) Distilled water; 2) Chlorine at 100 mg.L-1; 3) 8-hydroxyquinolin (8-HQC) at 100 mg.L-1; 4) 8-HQC at 200 mg.L-1; and 5) 8-HQC at 400 mg.L-1, which the stems remained in environmental conditions (20°C; 70% RH). On this experiment, it was possible to observe the damage caused by the treatments using chlorine at 100 mg.L-1 and high dosage of 8-HQC. The good quality where kept by using 8-HQC at 200 mg.L-1 and the average longevity of the experiment was 12 days. On the second experiment, the gerberas remained, during storage, in the following solutions: 1) Distilled water; 2) Citric acid at 64 g.L-1; 3) Chlorine at 25 mg.L-14) Chlorine at 50 mg.L-1; 5) 8-HQC at 25 mg.L-1 ; and 6) 8-HQC at 50 mg.L-1. With the results it was possible to verify the low efficiency of the citric acid at the used concentration and the lower damage by lower concentrations of chlorine and 8-HQC than the usually recommended, which kept the good quality of the flowers for... (Complete abstract, click electronic access below)

Le système antireflet (SAR) est d‟une grande importance pour les cellules photovoltaïques (PV), surtout pour celles de deuxième génération à base de couches minces. Au cours de ce travail de thèse, nous avons cherché à réaliser un SAR à la fois efficace et répondant aux critères de l‟industrie PV en termes de coût de production et de facilité de mise en oeuvre. Pour cela, nous avons particulièrement étudié le dépôt d‟oxynitrures de silicium (SiOxNy), comme élément de base de ces dispositifs. Les films sont élaborés par pulvérisation cathodique réactive radiofréquence à effet magnétron. Notre volonté a été d‟étudier à la fois le procédé de dépôt, les matériaux obtenus ainsi que la formation de dispositifs fonctionnels. Nous avons tout d‟abord présenté les deux voies d‟élaboration des couches minces de SiOxNy: par procédé conventionnel (PC) où les gaz réactifs ne sont pas pulsés, puis par le procédé de gaz réactif pulsé (PGRP). Nous avons aussi croisé une étude expérimentale par Spectroscopie d‟Emission Optique (SEO) et une modélisation du procédé afin de mieux appréhender les interactions des gaz réactifs avec la cible et leur effet sur le procédé. En parallèle, des dépôts ont été réalisés afin de vérifier la capacité de chacune des deux techniques à déposer des SiOxNy avec une gamme variable de compositions. Nous avons ensuite étudié l‟effet des paramètres de pulse de la méthode PGRP à la fois sur la structure, mais aussi sur les propriétés optiques et électriques des couches minces de SiOxNy. Nous avons cherché ici à valider le lien entre structure et indices de réfraction pour ces films. Enfin, pour réaliser un dispositif AR fonctionnel, des systèmes AR ont été tout d‟abord simulés avec un programme de calcul électromagnétique et optimisés grâce à un algorithme génétique. Les systèmes optimisés ont été ensuite déposés et caractérisés. Une réflectivité moyenne (entre 400 et 900 nm) inférieure à 5 % a ainsi été obtenue. / Antireflective systems (ARS) are of great importance for photovoltaic (PV) cells, especially those of second generation based on thin layers. In this work, we have been looking for achieving an ARS not only efficient but also meeting the criteria of the PV industry in terms of production cost and ease of implementation. For this, we particularly studied the deposition of silicon oxynitrides (SiOxNy), as the base materials of these devices. Films were deposited by cathodic reactive radiofrequency sputtering with a magnetron effect. We desired to study not only the deposition process, the obtained materials but also the realization of functional devices. We firstly presented two routes of SiOxNy thin films deposition: by the Conventional Process (CP) where the reactive gases are not pulsed, and by the Reactive Gas Pulsing Process (RGPP). We also combined an experimental study by Optical Emission Spectroscopy (SEO) and process modeling to better understand the reactive gases interactions with the target and their effect on the process. Simultaneously, films depositions were realized to check the potential of each technique to obtain a wide range of silicon oxinitrides composition.Then, we studied the effect of pulse parameters with the RGPP on the structure and also on the optical and electrical properties of SiOxNy thin films. We aimed here to confirm the link between structure and refractive indices for these films. Finally, to achieve a functional AR device, AR systems were firstly simulated with an electromagnetic calculation program and optimized using a genetic algorithm. The optimized systems were then deposited and characterized. An average reflectivity (between 400 and 900 nm) less than 5% was thus reached.