The detrimental effects rapid power fluctuation has on wireless narrowband communication channels has long been a concern of the mobile radio community as appropriate channel models seek to gauge link quality. Furthermore, advances in signal processing capabilities and the desire for spectrally efficient and low power radio systems have rekindled the interest for adaptive transmission schemes, hence some method of quickly probing the link quality and/or predicting channel conditions is required. Mathematical distributions for modeling the channel profile seek to estimate fading parameters from a finite number of discrete time samples of signal amplitude. While the statistical inference of such estimators has proven to be robust to rapidly shifting channel conditions, the benefits are quickly realized at the expense of processing complexity. Furthermore, computations of the best-known estimation techniques are often iterative, tedious, and complex. This thesis takes a renewed look at estimating fading parameters for the Nakagami-m, Rice-K, and Weibull distributions, specifically by showing that the need to solve transcendental equations in the estimators can be circumvented through use of polynomial approximation in the least-squared error sense or via asymptotic series expansion which often lead to closed-form and simplified expressions. These new estimators are compared to existing ones, the performances of which are comparable while preserving a lower computational complexity. In addition, the thesis also investigates the impact knowledge of the fading profile has on systems employing adaptive switching modulation schemes by characterizing performance in terms of average bit error rates (BER) and spectral efficiency. A channel undergoing Rice-$K$ fading on top of log-normal shadowing is simulated by correlating samples of received signal amplitude according to the user's doppler speed, carrier frequency, etc. The channel's throughput and BER performances are analyzed using the above estimation techniques and compared to non-estimation assumptions. Further discussion on narrowband fading parameter estimation and its applicability to wireless communication channels is provided. / Master of Science

Wireless technologies, such as satellite, cellular, and wireless internet are now commercially driven by ever more demanding consumers, who are ready for seamless integration of communication networks from the home to the car, and into the office. There is a growing need to quickly transmit information wirelessly and accurately. Engineers have already combine techniques such as orthogonal frequency division multiplexing (OFDM) suitable for high data rate transmission with forward error correction (FEC) methods over wireless channels. In this thesis, we enhance the system throughput of a working OFDM system by adding turbo coding and adaptive modulation (AD). Simulation is done over a time varying, frequency selective Rayleigh fading channel. The temporal variations in the simulated wireless channel are due to the presence of Doppler, a sign of relative motion between transmitter and receiver. The wideband system has 48 data sub-channels, each is individually modulated according to channel state information acquired during the previous burst. The end goal is to increase the system throughput while maintaining system performance under a bit error rate (BER) of 10-2. The results we obtained are preliminary. The lack of resources prevented us from producing detailed graphs of our findings. / Master of Science

Introduction Le cancer bronchique est un problème de santé publique en étant la première cause de décès par cancer dans le monde. Il reste de mauvais pronostic avec une résistance au Cisplatine qui est inéluctable dans l’histoire naturelle de la maladie. Nous nous sommes intéressés à l’association du CDDP aux inhibiteurs de la Poly(ADP-ribose) polymérase. Les inhibiteurs pharmacologiques de PARP sont source d’optimisme en oncologie clinique en monothérapie pour des tumeurs déficientes pour une voie de réparation de l’ADN et en association aux cytotoxiques classiques.Matériel et méthodes Nous avons généré 9 clones résistants au CDDP après culture de la lignée A549 dans des faibles doses de CDDP. Deux inhibiteurs pharmacologiques de PARP, CEP8983 (CEP) et PJ34 (PJ), ainsi que des siRNA spécifiques de PARP1 sont utilisés pour l’inhibition de PARP. L’apoptose est mesurée en cytométrie de flux par l’intermédiaire du potentiel membranaire de la mitochondrie DiOC6(3) et la perméabilisation de la membrane plasmique est évaluée par l’iodide de propidium. Le test de clonogénicité permet d’évaluer la capacité des cellules à échapper à la mort et à former une colonie. L’activité métabolique des cellules est mesurée par la mesure de clivage du sel de tetrazolium WST-1. L’immunofluorescence sur cellules fixées a permis d’étudier les dommages de l’ADN (γH2AX), la voie intrinsèque de l’apoptose (l’activation de la caspase 3 et la libération du cytochrome c) et la recombinaison homologue (BRCA1, RAD51). En Western Blot nous avons mesuré l’expression et l’activité de PARP (PAR) ainsi que l’expression d’acteurs de la réparation par excision de base (BER) (XRCC1 and polymérase β). Nous avons développé une méthode de détection de PAR en immunohistochimie sur des tissus inclus en paraffine. Résultats Nous avons trouvé un effet synergique pour l’association du CDDP aux inhibiteurs de PARP in vitro. De façon inattendue nous avons observé que les clones résistants au CDDP développent une addiction à PARP et sont spécifiquement tués par l’inhibition de PARP contrairement à la lignée parentale. Ces clones exhibent une hyperexpression et une hyperactivité de PARP. La réponse aux inhibiteurs de PARP corrèle plus précisément avec l’activation plutôt qu’avec l’expression de PARP, pointant que PAR est un biomarqueur plus précis que PARP. Nous avons observé que l’hyperactivation de PARP accompagne une résistance induite au CDDP et prédispose à une sensibilité aux inhibiteurs de PARP dans d’autres lignées de cancer bronchique (H460 et H1650), de mésothéliome (P31), de cancer de l’ovaire (TOV112D) et de col (HeLa). Dans des expériences in vivo nous avons noté que dans les xénogreffes obtenues à partir de clones résistants au CDDP, l’expression de PAR est stablement retrouvée en immunohistochimie. Ces tumeurs répondaient à l’inhibition de PARP par le PJ en diminuant l’expression de PAR. Les clones résistants au CDDP sensibilisés aux I PARP ont une recombinaison homologue conservée, cependant ont un déficit dans les étapes terminales du BER.Conclusion Nous avons identifié un effet synergique pour l’association des inhibiteurs de PARP au CDDP de des lignées de cancer bronchique. Nous avons observé une dépendance à PARP dans des lignées de cancer bronchique résistantes au CDDP et déficientes pour l’élongation du BER. Nous postulant que PAR est un biomarqueur spécifique de la réponse aux inhibiteurs de PARP. / Introduction Driven by the facts that non small cell lung cancer (NSCLC) is the leading cause of cancer-related morbidity and mortality worldwide and that NSCLC patients often develop resistance against Cisplatin (CDDP)-based therapies, we addressed the question of the combination therapy of CDDP with poly(ADP-ribose) polymerases (PARP) inhibitors. Inhibitors of PARP have raised great expectations for the treatment of a variety of cancers, either as monotherapeutic agent against DNA repair-deficient tumours or combined to DNA-damaging compounds.Material and methods We generated nine CDDP-resistant clones by prolonged exposure to low dose CDDP of the A549 NSCLC parental cell line. Two distinct PARP inhibitors, CEP8983 (CEP) and PJ34 (PJ) as well as PARP1 knockdown with small interfering RNAs (siRNAs) were used for PARP inhibition. Apoptosis was measured by the simultaneous assessment for the loss of the mitochondrial transmembrane potential (m) and the breakdown of the plasma membrane using the m-sensitive fluorochrome DiOC6(3) and the vital dye propidium iodide, respectively. Moreover clonogenic survival was assessed. In vitro assessments of the enzymatic activity of cells were based on the reduction of the colorless tetrazolium salt. Immunofluorescence microscopy determinations were performed with antibodies specific for DNA damage (γH2AX), intrinsic apoptosis (cleaved Caspase-3 and cytochrome c), and homologous recombination (RAD51 and BRCA1). Immunoblotting was assed for PARP1 expression and activity (PAR) and base excision repair (BER) effectors (XRCC1 and polymerase β). We developed an immunohistochemical staining method that specifically detects PAR on paraffin-embedded cell pellets and tissue sections.Results We found that PARP inhibitors and PARP1 siRNAs synergized with CDDP in the killing of NSCLC cells in vitro. Unexpectedly, CDDP-resistant NSCLC cell clones developed addiction to PARP hyperactivation, thereby becoming susceptible to apoptosis induction by PARP inhibition. We showed that these cisplatin-resistant clones, exhibited high PARP protein levels and increased PARP activity, leading to an increased poly-ADP ribosylation of cellular proteins, as compared to their parental, cisplatin-sensitive counterparts. These cisplatin-resistant cells become susceptible to cell death as induced by PARP inhibition, correlating with the hyperactivity of PARP (elevated PAR levels) more accuratly than with the overexpression of PARP. Suggesting that PAR levels may constitute a more accurate biomarker than PARP to predict the sensitivity of cells to PARP inhibition. We expanded the observation that cisplatin resistance causes PARP upregulation and hyperactivation and subsequent sensitization to PARP inhibition to additional five human cancer cell lines including two NSCLC (H1650 and H460), one mesothelioma (P31), one ovarian (TOV112D) and one cervical cancer (HeLa) cell line. To get further insight into this issue, we generated in vivo experiments. Tumors derived from CDDP-resistant cells were characterized by elevated levels of PAR suggesting that PAR levels are preserved during tumor formation. Those PAR-overexpressing tumors responded to the administration of PJ in vivo with a consistent reduction in PAR immunoreactivity. CDDP resistant clones that are specifically killed by PARP inhibitors assessed efficient homologous recombination repair however deficient BER elongation.Conclusion We showed a beneficial effect for the association therapy of PARP inhibitors with CDDP in several NSCLC cell lines. We have identified an addiction to PARP in CDDP resistant cell lines with deficient BER elongation. We postulate that PAR is a specific predictive biomarker for the response to PARP inhibitors.

La performance de démodulation des signaux GNSS existants, GPS L1 C/A, L2C ou L5, est satisfaisante en environnements ouverts où le C/N0 disponible est assez élevé. Cependant, en milieu urbain, le niveau de C/N0 du signal reçu est souvent très bas et est affecté de variations rapides qui peuvent nuire la démodulation des messages GNSS. Donc, car les applications du marché de masse sont appelées à être déployées dans ces environnements, il est nécessaire d'étudier et de chercher des méthodes de démodulation/décodage qui améliorent la performance de démodulation des messages GNSS dans ces environnements. Il est aussi nécessaire de considérer les nouveaux signaux GPS L1C et GALILEO E1. Ces signaux doivent fournir un service de positionnement par satellite dans tout type d'environnement, et spécifiquement en milieu urbain. Ainsi, cette thèse analyse aussi les performances de démodulation des nouveaux signaux GNSS tels que définis dans les documents publics actuels. De plus, de nouvelles structures de message GALILEO E1 sont proposées et analysées afin d'optimiser la performance de démodulation ainsi que la quantité d'information diffusée. En conséquence, le but principal de cette thèse est d'analyser et améliorer la performance de démodulation des signaux GNSS ouverts au public, spécifiquement en milieu urbain, et de proposer de nouvelles structures de messages de navigation pour GALILEO E1. La structure détaillée des chapitres de cette thèse est donnée ci-après. En premier lieu, le sujet de cette thèse est introduit, ses contributions originales sont mises en avant, et le plan du rapport est présenté. Dans le 2ième chapitre, la thèse décrit la structure actuelle des signaux GNSS analysés, en se concentrant sur la structure du message de navigation, les codages canal implantés et leurs techniques de décodage. Dans le 3ième chapitre, deux types de modèles de canal de propagation sont présentés pour deux différents types de scénarios. D'un côté, un canal AWGN est choisi pour modéliser les environnements ouverts. De l'autre côté, le modèle mathématique de Perez-Fontan d'un canal mobile est choisi pour représenter les environnements urbains et indoor. Dans le 4ième chapitre, une tentative pour effectuer une prédiction binaire d'une partie du message de navigation GPS L1 C/A est présentée. La prédiction est essayée en utilisant les almanachs GPS L1 C/A, grâce à un programme de prédiction à long terme fourni par TAS-F, et des méthodes de traitement du signal: estimation spectrale, méthode de PRONY et réseau de neurones. Dans le 5ème chapitre, des améliorations à la performance de démodulation du message de GPS L2C et L5 sont apportées en utilisant leur codage canal de manière non traditionnelle. Deux méthodes sont analysées. La première méthode consiste à combiner les codages canal internes et externes du message afin de corriger davantage de mots reçus. La deuxième méthode consiste à utiliser les probabilités des données d'éphémérides afin d'améliorer le décodage traditionnel de Viterbi. Dans le 6ième chapitre, la performance de démodulation des messages de GPS L1C et du Open Service GALILEO E1 est analysée dans différents environnements. D'abord, une étude de la structure de ces deux signaux est présentée pour déterminer le C/N0 du signal utile reçu dans un canal AWGN. Puis, la performance de démodulation de ces signaux est analysée grâce à des simulations dans différents environnements, avec un récepteur se déplaçant à différentes vitesses et avec différentes techniques d'estimation de la phase porteuse du signal. / The demodulation performance achieved by any of the existing GPS signals, L1 C/A, L2C or L5, is satisfactory in open environments where the available C/N0 is quite high. However, in indoor/urban environments, the C/N0 level of the received signal is often very low and suffers fast variations which can further affect the GNSS messages demodulation. Therefore, since the mass-market applications being designed nowadays are aimed at these environments, it is necessary to study and to search alternative demodulation/decoding methods which improve the GNSS messages demodulation performance in these environments. Moreover, new GNSS signals recently developed, such as GPS L1C and GALILEO E1, must also be considered. These signals aim at providing satellite navigation positioning service in any kind of environment, giving special attention to indoor and urban environments. Therefore, the demodulation performances of the new GNSS signals as they are defined in the current public documents is also analysed. Moreover, new GALILEO E1 message structures are proposed and analysed in order to optimize the demodulation performance as well as the quantity of broadcasted information. Therefore, the main goal of this dissertation is to analyse and to improve the demodulation performance of the current open GNSS signals, specifically in indoor and urban environments, and to propose new navigation message structures for GALILEO E1. A detailed structure of this dissertation sections is given next. First, the subject of this thesis is introduced, original contributions are highlighted, and the outline of the report is presented. Second, this dissertation begins by a description of the current structure of the different analysed GNSS signals, paying special attention to the navigation message structure, implemented channel code and their decoding techniques. In the third section, two types of transmission channel models are presented for two different types of environments. On one hand, an AWGN channel is used to model the signal transmission in an open environments. On the other hand, the choice of a specific mobile channel, the Perez-Fontan channel model, is chosen to model the signal transmission in an urban environment. In the fourth section, a tentative to make a binary prediction of the broadcasted satellite ephemeris of the GPS L1 C/A navigation message is presented. The prediction is attempted using the GPS L1 C/A almanacs data, a long term orbital prediction program provided by TAS-F, and some signal processing methods: spectral estimation, the PRONY method, and a neural network. In the fifth section, improvements to the GPS L2C and GPS L5 navigation message demodulation performance are brought by using their channel codes in a non-traditional way. Two methods are inspected. The first method consists in sharing information between the message inner and outer channel codes in order to correct more received words. The second method consists in using the ephemeris data probabilities in order to improve the traditional Viterbi decoding. In the sixth section, the GPS L1C and GALILEO E1 Open Service demodulation performance is analysed in different environments. First, a brief study of the structure of both signals to determine the received C/N0 in an AWGN channel is presented. Second, their demodulation performance is analysed through simulations in different environments, with different receiver speeds and signal carrier phase estimation techniques.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / A célula epitelial é o primeiro contato entre os micro-organismos e o hospedeiro. Essa interação pode levar a produção de diversas citocinas, quimiocinas, moléculas inflamatórias e também estimular a geração de espécies reativas de oxigênio (ERO). Neste trabalho avaliamos se a interação com as células HEp-2 poderia ser genotóxica para os mutantes derivados de Escherichia coli K-12 deficientes em algumas enzimas que fazem parte do sistema de reparo por excisão de base (BER). Além disto, avaliamos a expressão do sistema SOS, que é induzido pela presença de danos no genoma bacteriano. Os resultados obtidos mostraram a presença de filamentos, na interação com células HEp-2, principalmente, no mutante xthA (BW9091) e no triplo mutante xthA nfo nth (BW535). Quando a interação foi quantificada na ausência da D-manose, observamos um aumento das bactérias aderidas. Além disto, a quantidade e o tamanho dos filamentos também aumentaram, mostrando que as adesinas manose-sensíveis estavam envolvidas na filamentação bacteriana. Para comprovar se o aumento da filamentação observada neste ensaio foram uma consequência da indução do sistema SOS, desencadeada pela interação com as células HEp-2, quantificamos a expressão do SOS, na presença e na ausência da D-manose. De fato, observamos que a indução do SOS na ausência da D-manose foi maior, quando comparada, com o ensaio realizado na presença de D-manose. Além disto, observamos que a ausência de xthA foi importante para o aumento da filamentação observada na ausência de D-manose. Diante destes resultados, verificamos se a resposta de filamentação ocorreria quando as bactérias interagiam com uma superfície abiótica como o vidro. Observamos também inúmeros filamentos nos mutantes BER, BW9091 e BW535, quando comparados a cepa selvagem AB1157. Essa filamentação foi associada à indução do SOS, em resposta a interação das bactérias com o vidro. Em parte a filamentação e a indução do SOS observadas na interação ao vidro, foram associadas à produção de ERO. Quantificamos também o número de bactérias aderidas e observamos que as nossas cepas formavam biofilmes moderados. Contudo, a formação de biofilme dependia da capacidade da bactéria induzir o sistema SOS, tanto em aerobiose como em anaerobiose. A tensão do oxigênio foi importante para interação dos mutantes BER, uma vez que os mutantes BW9091 e BW535 apresentaram uma quantidade de bactérias aderidas menor em anaerobiose. Contudo, a diminuição observada não estava vinculada a morte dos mutantes BER. Também realizamos microscopia de varredura na cepa selvagem e nos mutantes, BW9091 e BW535 e confirmamos que as três cepas formavam biofilmes tanto em aerobiose como em anaerobiose. Observamos uma estrutura sugestiva de matriz extracelular envolvendo os biofilmes da cepa selvagem AB1157 e do mutante BW9091. No entanto, a formação desta estrutura por ambas as cepas dependia da tensão de oxigênio, pois nos biofilmes formados em anaerobiose essa estrutura estava ausente. Em conclusão, mostramos que na interação das bactérias com a superfície biótica e abiótica, ocorreu lesão no genoma, com indução do SOS e a resposta de filamentação associada. / The epithelial cell is the first contact between microorganisms and host. This interaction results in production of several cytokines, chemokines, and inflammatory molecules by epithelial cells and also stimulate the generation of reactive oxygen species (ROS). In the present study, we have evaluated whether the interaction to HEp-2 cells causes genotoxicity to mutants derived from Escherichia coli K-12 deficient in some enzymes that are part of the system of base excision repair (BER). Moreover, we measured the expression of SOS system, which is induced by the presence of damage to the bacterial genome. Our results showed mainly presence of filamentous bacterial growth in xthA mutant (BW9091) and triple xthA nfo nth mutant (BW535) when submitted to HEp-2 cells interaction assays. When experiments were performed in the absence of mannose, data showed enhanced interaction of viable bacteria to HEp-2 cells for all strains tested. Furthermore, the removal of D-mannose resulted in an increase in both number and size of bacterial filamentous forms, indicating the involvement of mannose-sensitive adhesins in the filamentation of these strains. In order to verify whether the increased filamentation growth in this assay was a consequence of SOS induction, triggered by interaction to HEp-2 cells, we measured expression of SOS in the presence and absence of D-mannose. Indeed, we observed higher expression of SOS response in the absence of mannose than in experiments performed in the presence of D-mannose. Moreover, we observed that the absence of xthA was important to filamentation increasing in absence of D-mannose. Based on these results, we verified if interaction to abiotic surfaces, like glass, could lead to filamentation of these strains. We also observed numerous filaments in BER mutants, BW9091 and BW535, when compared to wild-type strain AB1157. The filamentation observed was a consequence of SOS induction, triggered by attachment to the glass surface. In part, the filamentation and SOS induction observed in these experiments were related to ROS production. We also quantified interacted bacterial cells and it was observed moderated biofilm formation in all strains tested. However, biofilm formation depended on the ability of the bacteria to induce the SOS response, under both aerobic and anaerobic conditions. The oxygen tension was important factor for interaction of the BER mutants, since these mutants exhibited decreased quantitative adherence under anaerobic conditions. However, this decrease was not related to BER mutants death. Scanning electron microscopy was also performed in the wild-type strain and BER mutants (BW9091 e BW535) and biofilm formation was confirmed under both aerobic and anaerobic conditions. We observed a structure similar to a extracellular matrix which involved biofilms of wild type strain (AB1157) and xthA mutant (BW9091). However, the formation of this structure by both strains depended on the oxygen tension, since biofilm formation, under anaerobiosis condition, did not presented this structure. In conclusion, was provided that bacterial interaction to biotic and abiotic surfaces can lead to damage of bacterial genome, resulting in SOS induction and associated filamentation.

Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / A célula epitelial é o primeiro contato entre os micro-organismos e o hospedeiro. Essa interação pode levar a produção de diversas citocinas, quimiocinas, moléculas inflamatórias e também estimular a geração de espécies reativas de oxigênio (ERO). Neste trabalho avaliamos se a interação com as células HEp-2 poderia ser genotóxica para os mutantes derivados de Escherichia coli K-12 deficientes em algumas enzimas que fazem parte do sistema de reparo por excisão de base (BER). Além disto, avaliamos a expressão do sistema SOS, que é induzido pela presença de danos no genoma bacteriano. Os resultados obtidos mostraram a presença de filamentos, na interação com células HEp-2, principalmente, no mutante xthA (BW9091) e no triplo mutante xthA nfo nth (BW535). Quando a interação foi quantificada na ausência da D-manose, observamos um aumento das bactérias aderidas. Além disto, a quantidade e o tamanho dos filamentos também aumentaram, mostrando que as adesinas manose-sensíveis estavam envolvidas na filamentação bacteriana. Para comprovar se o aumento da filamentação observada neste ensaio foram uma consequência da indução do sistema SOS, desencadeada pela interação com as células HEp-2, quantificamos a expressão do SOS, na presença e na ausência da D-manose. De fato, observamos que a indução do SOS na ausência da D-manose foi maior, quando comparada, com o ensaio realizado na presença de D-manose. Além disto, observamos que a ausência de xthA foi importante para o aumento da filamentação observada na ausência de D-manose. Diante destes resultados, verificamos se a resposta de filamentação ocorreria quando as bactérias interagiam com uma superfície abiótica como o vidro. Observamos também inúmeros filamentos nos mutantes BER, BW9091 e BW535, quando comparados a cepa selvagem AB1157. Essa filamentação foi associada à indução do SOS, em resposta a interação das bactérias com o vidro. Em parte a filamentação e a indução do SOS observadas na interação ao vidro, foram associadas à produção de ERO. Quantificamos também o número de bactérias aderidas e observamos que as nossas cepas formavam biofilmes moderados. Contudo, a formação de biofilme dependia da capacidade da bactéria induzir o sistema SOS, tanto em aerobiose como em anaerobiose. A tensão do oxigênio foi importante para interação dos mutantes BER, uma vez que os mutantes BW9091 e BW535 apresentaram uma quantidade de bactérias aderidas menor em anaerobiose. Contudo, a diminuição observada não estava vinculada a morte dos mutantes BER. Também realizamos microscopia de varredura na cepa selvagem e nos mutantes, BW9091 e BW535 e confirmamos que as três cepas formavam biofilmes tanto em aerobiose como em anaerobiose. Observamos uma estrutura sugestiva de matriz extracelular envolvendo os biofilmes da cepa selvagem AB1157 e do mutante BW9091. No entanto, a formação desta estrutura por ambas as cepas dependia da tensão de oxigênio, pois nos biofilmes formados em anaerobiose essa estrutura estava ausente. Em conclusão, mostramos que na interação das bactérias com a superfície biótica e abiótica, ocorreu lesão no genoma, com indução do SOS e a resposta de filamentação associada. / The epithelial cell is the first contact between microorganisms and host. This interaction results in production of several cytokines, chemokines, and inflammatory molecules by epithelial cells and also stimulate the generation of reactive oxygen species (ROS). In the present study, we have evaluated whether the interaction to HEp-2 cells causes genotoxicity to mutants derived from Escherichia coli K-12 deficient in some enzymes that are part of the system of base excision repair (BER). Moreover, we measured the expression of SOS system, which is induced by the presence of damage to the bacterial genome. Our results showed mainly presence of filamentous bacterial growth in xthA mutant (BW9091) and triple xthA nfo nth mutant (BW535) when submitted to HEp-2 cells interaction assays. When experiments were performed in the absence of mannose, data showed enhanced interaction of viable bacteria to HEp-2 cells for all strains tested. Furthermore, the removal of D-mannose resulted in an increase in both number and size of bacterial filamentous forms, indicating the involvement of mannose-sensitive adhesins in the filamentation of these strains. In order to verify whether the increased filamentation growth in this assay was a consequence of SOS induction, triggered by interaction to HEp-2 cells, we measured expression of SOS in the presence and absence of D-mannose. Indeed, we observed higher expression of SOS response in the absence of mannose than in experiments performed in the presence of D-mannose. Moreover, we observed that the absence of xthA was important to filamentation increasing in absence of D-mannose. Based on these results, we verified if interaction to abiotic surfaces, like glass, could lead to filamentation of these strains. We also observed numerous filaments in BER mutants, BW9091 and BW535, when compared to wild-type strain AB1157. The filamentation observed was a consequence of SOS induction, triggered by attachment to the glass surface. In part, the filamentation and SOS induction observed in these experiments were related to ROS production. We also quantified interacted bacterial cells and it was observed moderated biofilm formation in all strains tested. However, biofilm formation depended on the ability of the bacteria to induce the SOS response, under both aerobic and anaerobic conditions. The oxygen tension was important factor for interaction of the BER mutants, since these mutants exhibited decreased quantitative adherence under anaerobic conditions. However, this decrease was not related to BER mutants death. Scanning electron microscopy was also performed in the wild-type strain and BER mutants (BW9091 e BW535) and biofilm formation was confirmed under both aerobic and anaerobic conditions. We observed a structure similar to a extracellular matrix which involved biofilms of wild type strain (AB1157) and xthA mutant (BW9091). However, the formation of this structure by both strains depended on the oxygen tension, since biofilm formation, under anaerobiosis condition, did not presented this structure. In conclusion, was provided that bacterial interaction to biotic and abiotic surfaces can lead to damage of bacterial genome, resulting in SOS induction and associated filamentation.

Made available in DSpace on 2016-04-18T21:39:47Z (GMT). No. of bitstreams: 4 Erik Aceiro Antonio1.pdf: 1548083 bytes, checksum: 089690da04ba664ec23f802cb3975826 (MD5) Erik Aceiro Antonio2.pdf: 1618157 bytes, checksum: efefcd4d6d658d457615e8757d4175d8 (MD5) Erik Aceiro Antonio3.pdf: 2722615 bytes, checksum: a3f70f5fd3c8b07408a62f1d5a6cfbc2 (MD5) Erik Aceiro Antonio4.pdf: 1214557 bytes, checksum: 8bf6858d70baeb72941ce7c5cc104437 (MD5) Previous issue date: 2008-06-30 / The advent of the Internet and the development of Information and Communication Technologies (ICT s)generated new spaces for communication and collaboration between groups of people in geographically distinct regions. The association of Web technology with instrument automation and control by computer has made possible the development of the so called Remote Laboratories or WebLabs - distributed environments that allow to access and control experiments remotely through a network or the Internet in real time and with the sensation of presence. In this work, a WebLab was developed for the study and caracterization of a WDM (Wave Division Multiplexing) system, aiming to support and complement activities in faceto-face and distance courses on Optical Communications. Drivers and graphic user interfaces (GUI s) were developed with the software LabVIEW for control and data acquisition of instruments used in a remote experiment to measure the basic features of a WDM system. An application was also developed with the software VPI for the numerical simulation of Bit Error Rate (BER) measurements. This work is part of the activities related to the participation of the Mackenzie Photonics Laboratory in the KyaTera Project of FAPESP s TIDIA Program. / O advento da Internet e o desenvolvimento das Tecnologias da Informação e Comunicação (TIC s) geraram novos espaços para a comunicação e colaboração entre grupos de pessoas localizadas em regiões geograficamente distintas. A associação da tecnologiaWeb com a automação e controle de instrumentos por computador tornou possível o desenvolvimento dos chamados Laboratórios Remotos ou WebLabs - ambientes distribuídos que permitem o acesso e controle remoto de experimentos através de uma rede de comunicação ou da Internet em tempo real e com sensação de presença. Neste trabalho, foi desenvolvido um WebLab para estudo e caracterização de um sistema WDM (Wave Division Multiplexing), destinado a apoiar e complementar atividades em cursos de Comunicações Ópticas presenciais e a distância. Foram desenvolvidos drivers e interfaces gráficas de usuário (GUI s) com o software LabVIEW para o controle e aquisição de dados dos instrumentos utilizados em um experimento remoto de medida das características básicas de um sistema WDM. Também foi desenvolvido um aplicativo com o software VPI que permite simular a medida da Taxa de Erro de Bit (BER) do sistema. Este trabalho é parte das atividades relacionadas à participação do Laboratório de Fotônica Mackenzie no Projeto KyaTera do Programa TIDIA da FAPESP.

The diploma thesis Simulation of Multipath Propagation of Multistate Modulations is focused on the development of an appropriate algorithm in MATLAB environment, which is capable to simulate the impact of the multipath propagation on received signal (error rate) on the basis of given parameters of the transmission channels. Mechanisms and characteristics of the wave propagation in communication environment, types of digital modulations and their most important parameters are described in the first part of this thesis. The second part is focused on the simulation itself. Created GUI (Graphical User Interface) is able to display constellation diagrams of transmitted and received signals, as well as their bit error rate. It is also possible to compare these data with the data of signal, which is passed by a non-fading channel.

The IEEE 802.11a protocol is part of the IEEE 802 protocols for implementing WLAN Wi- Fi computer communications in various frequencies. These protocols find applications worldwide, covering a wide range of devices like mobile phones, computers, laptops, household appliances, etc. Since wireless communication is being used, data that is transmitted is susceptible to noise. As a means to recover from noise, the data transmitted is encoded using convolutional encoding and correspondingly decoded on the receiver side. The decoder used is the Viterbi decoder, in the PHY layer of the protocol. This thesis investigates soft-decision Viterbi decoder implementations that meet the requirements of the IEEE 802.11a protocol. It aims to implement a rate-flexible design as a coarse grain re-configurable architecture using the SiLago framework. SiLago is a modular approach towards ASIC design. Components are designed as hardened blocks, which means they are synthesised and pre-verified. Each block is also abuttable like LEGO blocks, which allows users to connect compatible blocks and make designs specific to their requirements, while getting performance similar to that of traditional ASICs. This approach significantly reduces the design costs, as verification is a one-time task. The thesis discusses the strongly connected trellis Viterbi decoding algorithm and proposes a design for a soft decision Viterbi decoder. The proposed design meets the throughput requirements of the communication protocol and it can be reconfigured to work for 45 different code rates, with programmable soft decision width and parallelism. The algorithm used is compared against MATLAB for its BER performance. Results from RTL simulations, advantages and disadvantages of the proposed design are discussed. Recommendations for future improvements are also made. / IEEE 802.11a-protokollet är en del av IEEE 802-protokollen för att implementera WLAN Wi-Fi-datorkommunikation i olika frekvenser. Dessa protokoll används i applikationer över hela världen som täcker ett brett spektrum av produkter som mobiltelefoner, datorer, bärbara datorer, hushållsapparater etc. Eftersom trådlös kommunikation används är data som överförs känslig för brus. Som ett medel för att återhämta sig från brus kodas överförd data med hjälp av faltningskodning och avkodas på motsvarande sätt på mottagarsidan. Den avkodare som används är Viterbi-avkodaren, i PHY-skiktet i protokollet. Denna avhandling undersöker mjuka beslut Viterbi avkodarimplementeringar som uppfyller kraven i IEEE 802.11a protokollet. Det syftar till att implementera en hastighetsflexibel design som en grovkornig konfigurerbar arkitektur som använder SiLago ramverket. SiLago är ett modulärt synsätt på ASIC design. Komponenterna är utformade som härda block, vilket innebär att de är syntetiserade och förverifierade. Varje block kan också kopplas ihop, som LEGO block, vilket gör det möjligt för användare att ansluta kompatibla block och göra designer som är specifika för deras krav, samtidigt som de får prestanda som liknar traditionella ASICs. Detta tillvägagångssätt minskar designkostnaderna avsevärt, eftersom verifiering är en engångsuppgift. Avhandlingen diskuterar den starkt kopplade trellis Viterbi-avkodningsalgoritmen och föreslår en design för en mjuk Viterbi-avkodare. Den föreslagna designen uppfyller kommunikationsprotokollets genomströmningskrav och den kan konfigureras om för att fungera för 45 olika kodhastigheter, med programmerbar mjuk beslutsbredd och parallellitet. Algoritmen som används jämförs mot MATLAB för dess BER-prestanda. Resultat från RTL-simuleringar, fördelar och nackdelar med den föreslagna designen diskuteras. Rekommendationer för framtida förbättringar görs också.

International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / An implementation of a Pseudo Error Detection (PSED) system is presented and its performance in conjunction with smart antenna and smart diversity systems tested and evaluated. Non redundancy, instant response and relative simplicity make the Pseudo Error Detectors excellent real time error monitoring systems in smart antenna and smart diversity systems. Because of the Non-redundant Error Detection mechanism in Pseudo Error Detectors, we can monitor the error quality without any coding or overhead. The output of the pseudo error detector in AWGN, selective fading Doppler shift and other interference environments is directly correlated to the BER and BLER. This direct correlation makes it a great tool for online error monitoring of a system and can have numerous applications In a PSED the Eye diagram from the demodulator is sampled once per symbol. By monitoring and comparison of the eye at sampled intervals at different thresholds, we would know if an error has occurred. By integrating this result over a period of time we can get the averaged error level. The results provided in this paper were obtained and verified by both MatLab simulations using dynamic simulation techniques and hardware measurements over dynamic channels.