Dissertations / Theses: 'Viral traffic'

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Rizkallah, Gergès. "Le role de l'interaction des cellules dendritiques avec le virus HTLV-1 dans la dissémination virale : capture ou infection productive ?" Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1099/document.

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Le virus T lymphotrope humain de type 1 (HTLV-1) est l'agent étiologique de la leucémie à cellules T de l'adulte (ATL) et de la paraparésie spastique tropicale/myélopathie associée à HTLV-1 (HAM/TSP). Chez les patients chroniquement infectés, le provirus d'HTLV-1 est majoritairement retrouvé dans les lymphocytes T CD4+. Ex vivo, on peut aussi retrouver le provirus dans les lymphocytes T CD8+, les lymphocytes B, les monocytes, les cellules dendritiques (DCs) myéloïdes, les DCs plasmacytoϊdes (pDCs) et les macrophages. In vitro, HTLV-1 est capable d'infecter productivement les cellules lymphoïdes et les cellules dendritiques dérivées de monocytes humains (MDDCs). De par leur fonction et leur distribution dans l'organisme, les DCs pourraient être les premières cellules à interagir avec HTLV-1 au cours de la primo-infection. Elles seraient ensuite capables de transmettre HTLV-1 aux lymphocytes T CD4+. Cette hypothèse est soutenue par les travaux de notre équipe qui ont montré que les MDDCs sont plus susceptibles que des lymphocytes T autologues à l'infection par HTLV-1. Ainsi, les DCs constitueraient des relais importants pour l'établissement de l'infection chronique. Dans ce contexte, nous nous sommes demandés si toutes les populations de DCs étaient également susceptibles à l'infection par HTLV-1 et si elles transmettaient similairement HTLV-1 aux lymphocytes T. Pour cela, nous avons différencié trois sous types de MDDCs après l'exposition de monocytes humains à divers cocktails de cytokines : - les IL4-DCs (pour interleukine 4 - DCs) miment les DCs immatures myéloϊdes du sang, - les TGF-β DCs (pour tumor-growth factor β - DCs) miment les DCs mucosales à phénotype tolérogène, - les IFN-α DCs (pour interféron α DC) miment les DCs activées et inflammatoires recrutées au niveau des sites d'inflammation. Nous avons aussi traité au lipopolysaccharide (LPS) des IL-4 DCs afin de générer des DCs qui sur-expriment les marqueurs de maturation CD80 et CD86. Nos résultats montrent que les IFN-α DC et les IL-4 DCs traités au LPS ne supportent pas une infection productive au contraire des TGF-β DCs et des IL4-DCs qui sont productivement infectés par HTLV-1. La restriction virale des IFN-α DC et les IL-4 DCs traitées au LPS n'est pas due à leur production d'IFN. Nous avons montré que la susceptibilité des IL4-DCs à l'infection productive par HTLV-1 est liée à leur phénotype immature. De plus, nos résultats montrent qu'HTLV-1 est internalisé par macropinocytose dans les IL-4 DCs alors qu'il est internalisé par endocytose médiée par la clathrine dans les IFN-α DCs. Enfin, nous avons pu restaurer partiellement la susceptibilité à l'infection productive des IL-4 DCs traités au LPS et celle des IFN-α DCs et nous avons pu restreindre celle des IL-4 DCs immatures en modulant le pH de leurs endosomes. Ces résultats suggèrent que le virus utilise le trafic vésiculaire pour infecter les DCs et que le pH des vésicules conditionne, au moins partiellement, le devenir de l'infection productive. De plus, parmi les IL-4 DCs, les IL-4 DCs traités au LPS et les IFN α DCs, seules les IL-4 DCs qui sont productivement infectées peuvent transmettre HTLV-1 aux lymphocytes T. En conclusion, nos résultats suggèrent que c'est le sous type de DC que rencontre HTLV- 1 lors de la primo-infection ainsi que le trafic viral d'HTLV-1 dans la DC qui conditionnent ou pas l'établissement de l'infection productive de la DC ainsi que la transmission aux lymphocytes T
HTLV-1 (Human T cell leukemia/lymphoma virus type 1) is the etiological agent of Adult T cell Leukemia/Lymphoma (ATLL) and HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP). In chronically infected patients, the provirus is mainly detected in the CD4 T-cell population and, to a lesser extent in myeloid dendritic cells (DCs), plasmacytoid DCs (pDCs), macrophages and monocytes. Among the different DCs subsets found in vivo, myeloid DCs from the blood, tolerogenic or inflammatory DCs from mucosa may first encounter HTLV-1 during blood transmission, breast-feeding or sexual transmission, respectively. They would then be able to transmit HTLV-1 to CD4 + T cells. This hypothesis is supported by the recent work of our team that showed that monocyte derived dendritic cells (MDDCs) are more susceptible to HTLV-1 infection in comparison to autologous T cells. We therefore asked whether all these DCs subsets were equally susceptible to HTLV-1 and whether the nature of the DC subset would impact HTLV-1 spread to T-cells. Human monocytes obtained from healthy blood donors were differentiated into IL-4 DCs, TGF-ß DCs or IFN-a DCs. In vitro-derived immature IL-4 DCs, TGF-ß DCs and IFN-a DCs mimic myeloid, tolerogenic and inflammatory DCs, respectively. We also generated LPS-matured IL-4 DCs that exhibited a strong maturation profile with over-expression of maturation markers. We observed HTLV-1 protein expression and provirus accumulation in IL-4 DCs and TGF-ß DCs but not in IFN-a DCs and LPS-matured IL-4 DCs. Despite their increased ability to capture HTLV-1 virion compared to IL-4 DCs and TGF-ß DCs, IFN-a DCs and LPS-matured IL-4 DCs restricted HTLV-1 productive infection. This was not due to the antiviral activity of type–I interferon produced by IFN-a DC or LPS-matured IL-4 DCs. In contrast, we showed that these differences in susceptibility to HTLV-1 infection might be linked to the maturation phenotype of the DCs subsets and to a different trafficking of HTLV-1 in IL-4 DC vs. IFN-a DC. Finally, using IL-4DCs, LPS-matured IL-4 DCs and IFN-a DCs, we demonstrate that productive infection rather than trans-infection is required for HTLV-1 transmission from DCs to CD4 T-cells. Thus, our results demonstrate that the nature of the DCs encountered by HTLV-1 during primo-infection and the trafficking route of the virus through the vesicular pathway of these cells determine the efficiency of viral transmission to T-cells

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Renault, Noémie. "Trafic intracellulaire de la protéine Gag du virus Foamy." Paris 7, 2009. http://www.theses.fr/2009PA077154.

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Les virus foamy sont des rétrovirus complexes qui appartiennent à la famille des spumaviridae. Ces rétrovirus présentent de nombreuses particularités qui les différencient des orthorétrovirus comme l'existence d'ADN viral infectieux dans la particule virale ou celle d'un ARNm codant pour la polyprotéine Pol, ou encore l'absence d'un facteur de régulation post-transcriptionnelle de type Rev ou Rex. De la même manière, les protéines Gag ne présentent pas les caractéristiques fondamentales retrouvées chez les autres rétrovirus comme le clivage en matrice, capside et nucléocapside. Nous avons focalisé notre travail sur ces protéines structurales et sur leurs rôles tant lors des étapes précoces que tardives. Lors des étapes précoces, la polyprotéine Gag protège le génome viral et le guide sur le réseau microtubulaire jusqu'à la membrane nucléaire. Dans les cellules qui cyclent, les particules,virales enfantes du virus foamy sont retrouvées intactes au centrosome à partir de 4 h post-infection. La capside subit alors un désassemblage en partie dépendant de la protéase virale. A l'inverse, dans les cellules quiescentes, nous montrons que les capsides restent structurées autour centrosome. A la reprise du cycle cellulaire, le cycle réplicatif viral reprend avec le déshabillage de la capside et l'intégration du provirus. Les protéases cellulaires et virales, qui interviennent lors de la décapsidation, semblent ainsi inactives lorsque les cellules sont en phase GO. De manière non exclusive, les sites de clivage de ces protéases sur les protéines structurales du virus pourraient être inaccessibles dans ces conditions. Les protéines Gag jouent également un rôle clé lors des étapes tardives de l'infection, en étant responsables de l'assemblage des capsides qui a lieu dans le cytoplasme, autour du centrosome. De manière intéressante, avant l'assemblage, ces protéines transitent dans le noyau. Nous nous sommes intéressés à cette étape nucléaire et montrons que la protéine Gag est exportée du noyau grâce à un signal d'export nucléaire riche en leucine et sensible à la leptomycine B, présent dans la partie N-terminale de la protéine. Une protéine Gag mutée dans ce domaine est non seulement incapable de quitter le noyau mais interfère négativement avec la réplication d'un virus sauvage. Nous suggérons que les protéines Gag des virus foamy pourraient intervenir dans l’export nucléaire de l’ARN viral lors des étapes tardives de l'infection
Foamy viruses (FVs) are complex exogenous animal retroviruses that differ in many aspects of their life cycle from the orthoretroviruses such as human immunodefîciency virus (HIV). In particular, in FVvs, Gag and Pol proteins are expressed independently of one another, and both proteins undergo single clivage events. None of the conventional Gag landmarks of exogenous retroviruses, such as the major homology region or Cys-His motifs, are found in this protein. Instead, FV Gag harbors conserved C-terminal basic motifs, referred to as Gly-Arg (GR) boxes. Although the first GR (GRI) box binds viral nucleic acids and is required for viral genome packaging, the second (GRII) harbors a nuclear localization sequence (NLS) at its C-terminus, targeting Gag to the nucleus early after infection. GRII also contains a chromatin binding sequence (CBS) in its N-terminus, tethering the FV incoming pre-integration complex onto host chromosomes. The present work focuses on the structural Gag proteins, in early and late stages of infection. Troviral Gag proteins are involved in early stages of infection such as trafficking of incoming viruses nd nuclear import. FV Gag protein uses the microtubule network to reach the nucleus. In cycling cells,FV articles are structured at the centrosome 4 h post-infection. Then, the viral protease helps capsid for ncoating. In quiescent cells, we have shown that viral particles remain structured at the centrosome during everal weeks and that uncoating does not occur : this step is a limiting factor for infection although viral articles are still infectious. Upon cells reactivation, viral capsids undergo proteolysis and disassembly, llowing infection to proceed. During the late stages of infection, Gag undergoes transient nuclear trafficking after it synthesis, before returning back to the cytoplasm for capsid assembly and virus egress. The functional role of this nuclear stage, as well as the molecular mechanisms responsible for Gag nuclear export, are not understood. Here, we identify a leptomycin-sensitive nuclear export sequence (NES) within the N-terminus of the primate foamy virus Gag protein that is absolutely required for the completion of late stages of virus replication. Point mutation of conserved residues within this motif leads to nuclear retention of Gag and dramatically affects viral replication. Moreover, complementation experiments demonstrate that nuclear export-defective Gag mutants negatively interfere with virus release by sequestering wild-type Gag in the nucleus

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El, Meshri Salah Edin. "Etude du trafic intracellulaire de la protéine Gag du VIH et rôle de son domaine NCp7." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAJ025/document.

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La polyprotéine de structure Gag du VIH-1 est responsable de l’assemblage des particules virales dans les cellules infectées. Au niveau moléculaire, cette protéine s’oligomérise en formant des complexes Gag-Gag autour de deux plates-formes moléculaires, d'une part l'ARN génomique via son domaine NCp7 (NucleoCapsid protein 7) et d'autre part, la membrane plasmique via son domaine MA (Matrice). De plus, lors du trafic de Gag dans la cellule, Gag détourne les protéines ESCRT comme TSG101 et ALIX de la machinerie cellulaire afin de bourgeonner et d’être libérées dans le milieu extracellulaire. Dans cette thèse, nous avons étudié le rôle du domaine NCp7 seul ou au sein de Gag (GagNC) dans les interactions Gag-Gag et Gag-TSG101 en utilisant des approches biochimiques et de la microscopie de fluorescence quantitative. Les résultats ont montré que l'absence du domaine NCp7 affecte l’oligomerisation de Gag qui s’accumule alors dans le cytoplasme sous forme d’agrégats de taille importante. Par ailleurs, le trafic intracellulaire de Gag est affecté par les mutations dans le domaine GagNC avec une augmentation importante de temps nécessaire à Gag pour arriver à la membrane plasmique. Enfin, nous avons montré que GagNC i) renforce l’interaction entre le domaine p6 de Gag et TSG101 et ii) par sa fonction dans le trafic de Gag, est responsable de la localisation de TSG101 à la PM. Sur la base de ces résultats, des études sont maintenant en cours pour développer des tests afin d’identifier des molécules possédant un potentiel anti virale
The Gag structural polyprotein of HIV-1 orchestrates viral particle assembly in producer cells, in a process that requires two platforms, the genomic RNA on the one hand and a membrane with a lipid bilayer, on the other. During its transportation from translating ribosomes to plasma membrane, Gag hijacks cellular proteins of the cytoskeleton and the ESCRT proteins like TSG101, Alix, etc., to egress viral particles. However, a number of questions remain to be answered before they are clearly apprehended. In this thesis, , we studied the role of the NC domain alone or as part of Gag (GagNC) in Gag-Gag and Gag-TSG101 interactions, which are essential for the assembly and budding of HIV-1 particles using quantitative fluorescent microscopy and biochemical approach. Results, showed that the absence of NC domain lead to (1) an accumulation of Gag as large aggregates that are dispersed in the cytoplasm, (2) a decrease of Gag-Gag condensation and (3) a delay for Gag-Gag complexes in reaching the PM, (4) improved interaction between Gag and TSG101, and (5) by its virtue in Gag trafficking docks TSG101 to the PM. This regulatory effect of NCp7 domain in either TSG101 or Gag or both protein- regulated pathways during virus budding can be exploited to develop inhibitors targeting HIV-1

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Toledo, Marcelo Augusto Szymanski de 1987. "Trafego intracelular de vetores não-virais = desenvolvimento de proteínas de fusão para transporte de DNA plasmidial através da interação com proteínas motoras = Intracelullar traffic of non-viral vectors: development of recombinant fusion proteins to mediate plasmidial DNA transport by interaction with motor proteins." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316418.

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Orientadores: Adriano Rodrigues Azzoni, Anete Pereira de Souza
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-24T06:15:51Z (GMT). No. of bitstreams: 1 Toledo_MarceloAugustoSzymanskide_D.pdf: 15660446 bytes, checksum: 8e64c5b4455cf458c2eb0d9b8e030e70 (MD5) Previous issue date: 2013
Resumo: Apesar de seguros e simples de produzir, o uso de vetores não virais como o DNA plasmidial (DNAp) em estudos de terapia gênica e vacinação por DNA tem sido limitado pela baixa eficiência quando comparados aos vetores virais. Essa limitação provém principalmente da reduzida capacidade de superar as barreiras físicas, enzimáticas e difusionais encontradas durante o tráfego intracelular para o interior do núcleo das células alvo. Dentro deste contexto, o presente trabalho demonstra a utilização de cadeias leves modificadas de Dineína (Lc8 e Rp3) como vetores não-virais de entrega gênica. A escolha de cadeias leves de Dineína justifica-se pela possibilidade de utilizar o transporte retrógrado celular mediado por complexos motores de Dineína para facilitar o tráfego de material genético exógeno através do citoplasma em direção à periferia nuclear. Através da adição de pequenos domínios peptídicos, ricos em aminoácidos polares positivos (arginina e lisina), ao N-terminal de cadeias leves de Dineína foi possível conferir a estas proteínas a habilidade de interagir com material genético condensando-o em partículas. Ensaios de transfecção demonstraram que tais partículas apresentam elevada eficiência de entrega do material genético exógeno ao núcleo de células HeLa, eficiência esta superior àquela apresentada pelo peptídeo protamina, amplamente estudado como vetor não-viral de entrega gênica. A formação de complexos ternários utilizando-se DNA plasmidial, cadeias leves de Dineína modificadas e lipídios catiônicos apresentou eficiência de entrega superior àquelas apresentadas na ausência do lipídio. Adicionalmente, complexos de entrega formados apenas com DNA plasmidial e cadeias leves de Dineína modificadas apresentaram baixo efeito citotóxico em células HeLa, característica esta de grande relevância uma vez que a toxicidade dos vetores de entrega gênica atua como importante fator limitante em sua aplicação clínica. O mecanismo envolvido no processo de entrega gênica mediado por cadeias leves de Dineína modificadas também foi estudado, podendo ser observado que (1) a entrada dos complexos de entrega na célula é altamente dependente do processo de endocitose, (2) a eficiência de entrega observada depende da rede de microtúbulos e (3) parte significativa dos complexos de entrega é degradada na via de endossoma/lisossomo celular. Os vetores não-virais de entrega gênica descritos no presente estudo associam elevada eficiência de transfecção, baixa toxicidade celular e relativo baixo custo de produção, uma vez que as cadeias leves de Dineína recombinantes são produzidas em sistema heterólogo utilizando-se Escherichia coli. Ressalta-se ainda a possibilidade de adição de novos domínios peptídicos às cadeias leves de Dineína modificadas, agregando novas funções/capacidades que poderiam resultar em maior eficiência de entrega gênica através da otimização dos processos de internalização celular ou escape endossomal. A abordagem de se utilizar a via de transporte retrógrado celular para o desenvolvimento de vetores não-virais para entrega gênica é pouco explorada pela comunidade científica e o presente estudo apresenta-se entre os poucos da área, esperando assim contribuir para o desenvolvimento de vetores não-virais mais eficientes e seguros
Abstract: The use of non viral vectors such as plasmidial DNA (pDNA) in gene therapy and DNA vaccination protocols has been limited due to its low transfection efficiency when compared to viral vectors. This limitation occurs mainly due to the physical, enzymatic and diffusion barriers faced during the transport of the genetic material to the nucleus of target eukaryotic cells. Regarding this subject, the present work demonstrates the feasibility of using modified Dynein light chains (Lc8 and Rp3) as non viral vectors for gene delivery. The use of Dynein light chains relies on the possibility to exploit the Dynein based cellular retrograde transport in order to improve the exogenous genetic material transport across the citosol towards the nuclear periphery. By adding small peptide domains, based in positively charged aminoacids (arginine and lysine) to the N-terminal of Dynein light chains, the resulting recombinant proteins were able to interact and condense genetic material into delivery particles. Transfection assays demonstrated that these particles are highly efficient to delivery plasmidial DNA to nucleus of HeLa cells when compared to the transfection efficiency presented by protamine, a well characterized non viral vector peptide. Ternary complexes formed by modified Dynein light chains, pDNA and a cationic lipid showed even higher transfection efficiency. Additionally, the light chain based non viral delivery vectors presented low citotoxic effect to HeLa cells, a valuable feature as toxicity is regarded as one of the main concerns on delivery vectors development. The mechanism by which the modified Dynein light chain based vectors mediates gene delivery was also investigated and we could observe that (1) the internalization process deeply relies on endocytosis, (2) it depends on the microtubule network and (3) a significant fraction of the delivery complexes are trapped and degraded in the endocytic pathway. The non viral vectors developed in the present study combine high transfection efficiency, low toxicity and relative low production cost, as all modified proteins were produced in Escherichia coli prokaryotic host. Its noteworthy that additional peptide domains can be further associated to the delivery vectors described providing it with new abilities such as higher internalization or endosomal escape capacity. The approach to use the cellular retrograde transport in order to develop non viral vectors is poorly exploited by the scientific community and the present study stands among few in the field hopefully contributing to the development of more efficient and safer non viral vectors for gene delivery
Doutorado
Genetica de Microorganismos
Doutor em Genetica e Biologia Molecular

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Bouard, David. "La glycoprotéine d'enveloppe rétrovirale : trafic intracellulaire et recrutement lors de l'assemblage viral." Lyon, École normale supérieure (sciences), 2008. http://www.theses.fr/2008ENSL0471.

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Grigorov, Boyan. "Studying the traffic and assembly of HIV-1 Gag." Lyon, École normale supérieure (sciences), 2007. http://www.theses.fr/2007ENSL0398.

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Paris, Joris. "Trafic intranucléaire du rétrovirus Foamy." Paris 7, 2014. http://www.theses.fr/2014PA077053.

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La protéine Gag des rétrovirus exerce plusieurs fonctions au cours du cycle réplicatif, notamment en détournant de nombreuses machineries cellulaires. Dans le cas de PFV (Prototype Foamy Virus), la protéine Gag possède un NES (Nuclear Export Signal) permettant d'exporter son ARN génomique favorisant ainsi l'assemblage des capsides virales. Nous avons identifié une séquence de loCalisation nucléolaire (NoLS) dans la partie C-terminale de la protéine Gag. Ce NoLS est composé de 2 régions, riches en arginine et en glycine qui sont nécessaires et suffisantes pour le ciblage au nucléole. L'arginine R540 est méthylée par PRMT-1 régulant ainsi les fonctions NoLS vs CBS de la protéine Gag. Pour étudier, l'étape nucléolaire du virus PFV, nous avons utilisé différentes conditions permettant de ralentir le trafic intracellulaire (hypoxie et/ou traitement à la leptomycine B) et un système de piège permettant de retenir Gag au nucléole. Dans les 2 expériences, Gag a été détectée dans le nucléole. Nous avons aussi développé une approche basée sur l'utilisation d'un ribozyme nucléolaire qui est capable de cliver spécifiquement l'ARNg de PFV au nucléole
The structural Gag protein hijacks many cellular machineries to fulfill its distinct and fundamental roles in the replication of retroviruses. In the case of the prototype foamy virus (PFV), Gag contains a nuclear export signal (NES) which allows the gRNA-Gag complex to be exported to the cytoplasm prior to capsids assembly and virus egress. We identified a nucleolar localization sequence (NoLS) in the C-terminus of PFV Gag. This NoLS contains two regions, rich in arginine and glycine, which are necessary and sufficient for nucleolar targeting. The methylation of Arginine R540 by PRMT-1 regulates the functions NoLS vs CBS of Gag. To study the nucleolar step of PFV replication, we used different conditions that slow down intracellular trafficking (hypoxia and/or treatment with leptomycin B) and also a molecular trap system to retain Gag into the nucleolus. In both cases, Gag was detected in the nucleolus. We also developed an approach, based on a ribozyme fused to a snoRNA able to cleave specifically PFV gRNA in the nucleolus

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Charrat, Coralie. "Formulation de nanoparticules d’ADN fonctionnalisées par des peptides ligands des chaînes LC8 de la dynéine pour améliorer le trafic intracellulaire dans le transfert de gènes non viral." Thesis, Nice, 2016. http://www.theses.fr/2016NICE4017/document.

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L’objectif repose sur l’élaboration de vecteurs d’ADN fonctionnalisés par des séquences peptidiques, DLC8-AS, ciblant les chaînes légères LC8 de la dynéine cytoplasmique, pour obtenir un transport actif jusqu’au noyau le long des microtubules (MTs). Des travaux précédents, menés sur des fluosphères fonctionnalisées par des DLC8-AS, ont montré une efficacité remarquable à condition de travailler avec de hauts taux de ligands. De tels niveaux de ligands ne sont pas transposables à des nanoparticules (NPs) d’ADN car ils affectent grandement leur stabilité colloïdale. Pour compenser cela, nous avons développé dans cette thèse, des NPs d’ADN faiblement fonctionnalisées (2-10 mol %) portant des dimères de DLC8-AS afin de bénéficier d'un effet dimérique vis-à-vis de la dynéine qui augmente l'affinité. Parmi les systèmes testés, 2 ont montré un gain lié à l’effet dimérique des DLC8-AS. Le 1er est basé sur un amphiphile cationique dimérisable de la cystéine, utilisé avec son homologue pegylé portant un motif DLC8-AS, pour produire, via l’oligomérisation des thiols, une population monodisperse de petites NPs d’ADN décorées (~60 nm). Les expériences menées sur cellules HeLa ont montré que les NPs décorées par les dimères de DLC8-AS avaient des efficacités de transfection améliorées (~250 fois) grâce à un mécanisme dépendant du système dynéine/MTs. Dans l’autre système, la surface de polyplexes de PEI a été décorée avec des amphiphiles octaarginine mono- ou bis-DLC8-AS. De façon remarquable, l’efficacité de transfection des polyplexes portant les ligands dimériques a été améliorée d’un facteur 50 par rapport au JetPEI standard. Ici encore, le mécanisme dépend des MTs
The aim consists in engineering DNA carriers functionalized by peptide sequences, DLC8-AS, targeting the LC8 light chains of cytoplasmic dynein, to promote active transport towards the nucleus along the microtubules (MTs).Dépôt de thèseDonnées complémentairesPrevious works based on polystyrene fluospheres functionalized with DLC8-AS, showed a noteworthy transfection enhancement but as a cost of high levels of ligands. Such levels of functionalization are unsuitable for maintaining sufficient colloidal stability of DNA nanoparticles (NPs). In order to compensate for this, we developed in this thesis weakly functionalized DNA NPs (2-10 mol %) bearing dimers of DLC8-AS to benefit from a dimeric effect toward the dynein which increase the affinity. Among our designed systems, two revealed the benefit from taking advantage from the dimeric effect of DLC8-AS. The 1st one relies on a cationic and dimerizable cysteine based amphiphile, which was used with its dimerizable pegylated homologue containing DLC8-AS, to produce, through a thiol-disulfide oligomerisation process, a monodisperse population of small sized functionalized DNA NPs (~60 nm). Experiments carried out onto HeLa cells, showed that DNA NPs functionalized with DLC8-AS dimers exhibited enhanced transfection properties (~250 times) through a dynein/MTs dependant mechanism. The second consists in functionalizing the surface of PEI polyplexes with octaarginine amphiphiles carrying a mono- or bis-DLC8-AS. Remarkably, the transfection efficiency of polyplexes bearing the dimeric ligands was increased by a 50 times factor compared to the JetPEI golden standard. Here too, the mechanism strongly depends on MTs

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Vertiz, Zavaleta Julio Cesar, and Avalos Victor Eduardo Ramon. "Propuesta de mejora de niveles de servicio en la intersección vial entre la carretera Panamericana Sur km 37.5 y el puente Arica en la ciudad de Lima." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/648867.

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La Carretera Panamericana Sur km. 37.5 y el Puente Arica, es una intersección vial tipo Diamante Convencional partido sin semáforos, ubicado en el distrito de Lurín y provincia de Lima. Esta intersección presenta congestionamiento vehicular ocasionando pérdida de horas hombre. Debido a esto, se determinó los niveles de servicio actuales, a través del software Synchro 8.0, mediante aforos vehiculares tomados en campo. Los niveles de servicio obtenidos fueron muy bajos y demoras elevadas. Como consecuencia se plantearon y modelaron con el software Synchro 8.0 diferentes propuestas para solucionar la congestión vehicular, tales como; Implementación de cruceros semafóricos con diferentes diseños, implementación de mini óvalos dentro de la intersección y en los extremos de la intersección, y un intercambio vial de tipo Diamante Divergente. La propuesta de solución se inicia con la comparación de resultados obtenidos de las alternativas para el escenario actual y proyectado a 5 y 10 años. En consecuencia, se obtuvieron dos propuestas que solucionan la congestión vehicular actual y proyectada a 5 años. La primera es la implementación de cruceros semafórico con un carril exclusivo para el giro libre a la derecha y la segunda es la implementación de un novedoso intercambio vial de tipo Diamante Divergente, mientras que las demás propuestas no son sostenibles en la proyección del tránsito futuro. Por otro lado, si bien es cierto que ambas propuestas mejoran y dan solución al problema planteado la segunda presenta mejores niveles de servicio y menores demoras en la proyección a 10 años.
The South Pan American Highway km. 37.5 and the Arica Bridge, is a Conventional Diamond-type road intersection without traffic lights, located in the district of Lurín and province of Lima. This intersection presents vehicular congestion causing loss of man-hours. Due to this, the current service levels were determined, through Synchro 8.0 software, through vehicle capacities taken in the field. The service levels obtained were very low and delays were high. As a consequence, different proposals were proposed and modeled with Synchro 8.0 software to solve vehicular congestion, such as; Implementation of traffic lights with different designs, implementation of mini ovals within the intersection and at the ends of the intersection, and a Divergent Diamond road interchange. The solution proposal begins with the comparison of results obtained from the alternatives for the current scenario and projected at 5 and 10 years. Consequently, two proposals were obtained that solve the current and projected vehicular congestion at 5 years. The first is the implementation of traffic light cruises with an exclusive lane for the free right turn and the second is the implementation of a new Divergent Diamond interchange, while the other proposals are not sustainable in the projection of future traffic. On the other hand, although it is true that both proposals improve and solve the problem posed, the second presents better levels of service and less delays in the 10-year projection.
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Huanca, Tarazona Samuel David, and Quispe Angel Abel Rojas. "Propuesta de mejora del diseño vial del óvalo La Curva de Chorrillos validado con el software Vissim 9.0." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2019. http://hdl.handle.net/10757/626486.

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La presente tesis se basa en el análisis del flujo vehicular, presente en el óvalo La Curva, ubicada en el distrito de Chorrillos, Departamento de Lima-Perú. El proyecto evalúa las condiciones de servicio, diseño del óvalo y el tráfico vehicular. Esta evaluación es realizada mediante un modelo microscópico que es simulado en el software Vissim 9.0. La construcción del modelo consiste en 4 fases. La primera, trata del análisis previo, que abarca desde la recolección de datos hasta el procesamiento en gabinete. Por un lado, la toma de medidas geométricas se realizó en un día de menor volumen vehicular. Por otro lado, el aforo vehicular y peatonal se realizó en un día típico. La segunda fase consiste en el modelamiento inicial, que busca trasladar el diseño geométrico actual al Vissim para proceder con la microsimulación. Asimismo, se realizaron múltiples corridas hasta lograr la optimización del modelo, previo precalentamiento y calibración del mismo. La tercera fase analiza el diseño propuesto en base a los parámetros de eficiencia vehicular, como son el tiempo de viaje (demoras), la longitud de cola y el nivel de servicio. La propuesta busca optimizar el sistema de semaforización, actualmente existente e inoperativa, y un cambio de nivel en una de las avenidas que concurre mayor cantidad flujo vehicular. En la última fase se busca evaluar y comparar los resultados, tanto de la situación actual como de la alternativa propuesta. Finalmente, los parámetros que presenten mejoras en su servicio serán determinantes para reducir el problema de congestión vehicular.
This thesis is based on the analysis of vehicle flow, present in the La Curva oval, located in the district of Chorrillos, Department of Lima-Peru. The project evaluates service conditions, oval design and vehicular traffic. This evaluation is done through a microscopic model that is simulated in Vissim 9.0 software. The construction of the model consists of 4 phases. The first one deals with the previous analysis, which ranges from data collection to cabinet processing. On the one hand, the geometric measurements were taken on a day with less vehicular volume. On the other hand, vehicular and pedestrian traffic was performed on a typical day. The second phase consists of the initial modeling, which seeks to transfer the current geometric design to the Vissim to proceed with the microsimulation. Likewise, multiple runs were performed until the model was optimized, after preheating and calibrating it. The third phase analyzes the proposed design based on vehicle efficiency parameters, such as travel time (delays), tail length and service level. The proposal seeks to optimize the traffic signaling system, currently existing and inoperative, and a change of level in one of the avenues that has the greatest amount of traffic flow. In the last phase, the aim is to evaluate and compare the results, both of the current situation and of the proposed alternative. Finally, the parameters that present improvements in their service will be decisive to reduce the problem of vehicular congestion.
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Guevara, Delgado Percy Jose Manuel, and Ita Jherson Daniel Norabuena. "Análisis y propuesta de mejora de la seguridad vial en la carretera Panamericana Norte, tramo variante de Pasamayo del km 55 al km 70 aplicando la metodología del manual de seguridad vial." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2019. http://hdl.handle.net/10757/626485.

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Entre los años 2015 y 2017 se aprecia el incremento de accidentes de tránsito en la red vial no urbana (carreteras), debido probablemente debido al aumento del flujo vehicular, el deficiente diseño geométrico, el deterioro y falta de mantenimiento de la vía. El tramo Variante de Pasamayo de la carretera PE-1N correspondiente a la Red Vial N° 5, no está excluida de este cambio, observándose como los accidentes de tránsito se han incrementado en esta vía. Debido a esta problemática es necesario determinar que herramientas de seguridad vial son necesarias implementar en la carretera Variante de Pasamayo para reducir la frecuencia de accidentes de tránsito. Esta investigación está enfocada en el análisis y propuestas de mejora de la Seguridad Vial en la Variante de Pasamayo aplicando la metodología de Inspección de Seguridad Vial (ISV) y el Método Predictivo del Highway Safety Manual (HSM) de acuerdo al nuevo Manual de Seguridad Vial (2017). La aplicación de la metodología de la Inspección de Seguridad Vial dio como resultado la identificación de tramos de concentración de accidentes los cuales son: Tramo I (Km 67+500 al Km 68+500) y el Tramo II (Km 68+500 al Km 69+500). Una vez identificados los tramos de concentración de accidentes, se procedió a utilizar el método predictivo del HSM para predecir la frecuencia de accidentes primero en las condiciones reales y luego analizando el tramo con las mejoras planteadas. Las propuestas de mejora para el Tramo I analizado son la ampliación de la berma a 3 metros, la implementación de bandas sonoras transversales y la implementación de barreras de contención. Mediante el análisis de efectividad de las mejoras de seguridad vial propuestas con el método predictivo del HSM se obtuvo una reducción del 56% de la frecuencia de accidentes. Se recomienda para futuras investigaciones que la información estadística de los accidentes registrados por la Policía Nacional sea más específica y detallada para poder utilizar correctamente el método predictivo del HSM.
This research is focused on the analysis and improvement proposals in the Pasamayo Variant (Lima), applying the Road Safety Inspection (ISV) methodology and the Highway Safety Manual (HSM) Predictive Method according to the new Safety Manual Road (2017). Where the application of road safety inspection includes the identification of the various areas where road safety is potentially poor due to various conditions and characteristics, according to a format that the manual itself, we provide and then statistical processes to determine the precise stretches of accident. Also the Manual of safety of the predictive method of the road (HSM), which involves the collection and processing of accidents originated and subscribed in the studied section in a period of approximately three years, the content, classification of vehicular traffic is also analyzed ( IMDA) and the lifting of geometric characteristics; with the objective of finding, in the first place: The prediction of the average frequency of expected accidents (Nesperado) with the current conditions of the site; Finally, the HSM is used to carry out a second prediction in which the road conditions have been changed with improvement proposals with the aim of reducing the percentage of expected accidents. The Road Safety Inspection Application and the Road Safety Manual, as it is called the identification of those areas where road safety has deficiencies and intervention is necessary in order to preserve the safety status of people. Finally, it should be mentioned that this research is a methodology that is not known in Peru, which should be implemented before, during and after the process of construction of a road in order to reduce the victims of traffic accidents.
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Pires, Ricardo. "Etudes structurales et fonctionnelles de la protéine ALIX." Phd thesis, Université Joseph Fourier (Grenoble), 2008. http://tel.archives-ouvertes.fr/tel-00332814.

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Alix est une protéine adaptatrice impliquée dans plusieurs processus intracellulaires, dont l'apoptose, l'endocytose et le trafic membranaire, le bourgeonnement de certains rétrovirus (ex. HIV-1, EIAV) à travers la membrane plasmique ou encore la cytokinèse. Alix est constituée de trois domaines majeurs: un domaine BRO N-terminal, un domaine spécifique « en V » central (Alix-V) et un domaine C-terminal riche en prolines (PRD). Nous avons montré que la forme tronquée en C-terminal au niveau du domaine PRD (Alix-∃PRD) formait des monomères et des dimères en solution, et que le domaine Alix-V était suffisant pour permettre cette dimérisation. La diffraction de rayons X aux petits angles (SAXS) a montré que Alix-∃PRD se structurait en une forme incurvée et allongée qui rappelle les domaines BAR impliqués dans les phénomènes d'incurvation de membrane. Bien que l'interaction d'Alix avec la membrane ait été mise en évidence in vitro, sa capacité à déformer la membrane doit encore être confirmée. En outre, nous avons déterminé lors d'expériences de microcalorimétrie que les formes monomériques et dimériques de Alix-V interagissent avec un peptide dérivé de la protéine p9 EIAV Gag avec une affinité de l'ordre du micromolaire. Des cristaux de la forme dimérique de Alix-V ont été obtenus. Ces cristaux présentaient un faible pouvoir de diffraction (10Å). En revanche, des cristaux diffractant à 3Å ont été obtenus à partir d'une forme mutante de Alix-V (Mut1) incapable de dimériser et qui se structure en une forme monomérique ouverte et allongée ; la résolution de cette structure est en cours. De plus, nous avons montré que l'absence de relarguage des particules virales (VLP) après surexpression de la forme humaine de Alix-∃Bro (résidus 358-868) pouvait être rétablie à partir de la version Mut1 de cette forme, ce qui suggère donc un rôle de cette dimérisation dans le relarguage des VLP. La protéine Alix-V dimérique a également été utilisée pour produire un antisérum Alix, qui a montré que la protéine endogène Alix pouvait être co-localiser avec les endosomes de recyclage. Enfin, nous avons montré que CHMP4B formant des structures polymériques en anneaux, pouvait interagir avec Alix. L'ensemble de ces résultats donne de nouvelles informations sur la flexibilité conformationnelle d'Alix et, associée avec CHMP4, sur son implication dans les processus de bourgeonnement membranaire. Ce travail définit également le cadre des futures analyses fonctionnelles visant à définir le rôle de la protéine dimérique Alix dans les cellules infectées par le virus HIV-1.

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Lambelé, Marie. "Etude du trafic intracellulaire des glycoprotéines d'enveloppe d'isolats primaires du virus de l'immunodéficience humaine de type 1 et de son impact sur l'assemblage viral." Tours, 2007. http://www.theses.fr/2007TOUR3801.

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Les glycoprotéines d'enveloppe (Env) de VIH-1 se caractérisent par une variabilité génétique qui peut toucher les motifs impliqués dans la régulation de leur trafic intracellulaire. Nous avons ainsi mis en évidence, pour certaines Env d'isolats primaires, un polymorphisme dans ces motifs. Nous avons pu montrer que ce polymorphisme naturel affectait la distribution intracellulaire des Env. Cette modification du trafic intracellulaire perturbe l'assemblage viral en diminuant l'incorporation des Env à la surface des virions, et de ce fait les capacités réplicatives des virus produits. Cependant, il semble que, dans les Env. De VIH-1 primaires, des déterminants additionnels, puissent modifier le trafic intracellulaire de ces protéines. Cette modification de trafic pourrait, par ailleurs, contribuer à l'échappement du virus au système immunitaire. Ces travaux amènent de nouveaux éléments sur la compréhension des moyens adoptés in vivo par le VIH-1 pour s'assurer d'une propagation optimale
The envelope glycoprotein (Env. ) of HIV-1 is characterized by an important polymorphism that can affect motifs involved in the regulation of the intracellular trafficking. Her, we investigated four envelope genes with natural polymorphism within these motifs. We showed that this polymorphism might influence the intracellular distribution of Env. This modification affects viral assembly by diminution of Env incorporation into virions and, thus, viral replication capacity. Furthermore, it seems that additional determinants regulate intacellular trafficking of primary Env. This traffic's modification could in part contribute to viral evade from immune system. These work bring new insight in the understanding of viral life and its capacity to insure optimal propagation in vivo

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Hållström, Mattias. "EDL(s) Electronic Driving License(s) : To increase traffic safety and improve other functions vital to society by implementing and deploying an electronic driving license (EDL) framework." Thesis, Umeå universitet, Institutionen för datavetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-102495.

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Researcher Fred Goldberg closed a report by expressing, "It is now up to the politicians to create a safer traffic environment by utilizing new technology for the benefit of society" (Goldberg, 1995). And as he stated prior to that quote, a technique is available to prevent unlawful driving, to effectively reduce drunken driving and, among other things, to reduce theft of cars. This report presents the available technology and design that make it possible to incorporate an electronic driving license (EDL) framework into everyday life. This report will focus on how such technology could be used to prevent drivers from driving without valid driving licenses and to improve traffic safety in numerous other ways. The report presents the existing laws and regulations that govern the area of usage and describes how such legal aspects affect the design and deployment of an EDL framework. The presented legislation is extracted primarily from the European Union in general, and as a national example, Swedish legislation is often used. Moreover, the report will present technology that could be used to implement an EDL framework using examples of implementations and design, including license verification and an EDL. The implementation and deployment of an EDL framework could result in privacy concerns, and such aspects are discussed in a chapter where it is stated that security and privacy issues must be considered, as the potential for misuse is great. The level of privacy must be analysed in relation to the lifesaving potential of such a framework.

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Alvarado, Azurin Vanessa Alexandra, and Azalde Edson Ivan Valle. "Propuesta de gestión del tránsito para la reducción del congestionamiento en la Av. Alfredo Benavides entre los tramos Ovalo Higuereta y Av. Velasco Astete en el Distrito de Santiago de Surco utilizando el programa de simulación Synchro 8.0." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2019. http://hdl.handle.net/10757/628231.

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El congestionamiento vehicular se ha convertido en un problema abrumador para los habitantes de la ciudad de Lima. Frente a este problema, existen alternativas de mejoras en el tránsito vehicular que permiten minimizar el tiempo perdido. Este problema se evidencia en muchas avenidas y calles de esta ciudad; sobre todo en horas pico. En ese sentido, la presente tesis, aporta una solución para ser aplicada en la avenida Alfredo Benavides entre los tramos del óvalo Higuereta y avenida Velasco Astete. Así mismo, la finalidad es aplicar la gestión de la oferta enmarcados a la optimización y coordinación de fases semafóricas y a la mejora de indicadores de tráfico, como son: los grados de saturación, niveles de servicio, demoras por espera y ciclos semafóricos en las intersecciones. Para este propósito, se utiliza el software para la simulación del tránsito a nivel mesoscópico Synchro 8, el cual permite modelar la situación actual para el análisis de la problemática y posterior propuesta de solución. En consecuencia, esta tesis evaluará el comportamiento vehicular de la red estudiada mediante la metodología HCM en donde no considera ciclistas y peatones. Finalmente, la propuesta de solución indica que si es posible optimizar y disminuir el congestionamiento vehicular del tramo en estudio. Esto sin alterar, de sobre manera, la infraestructura o generar mayores costos de implementación a la vía.
Traffic congestion has become an overwhelming problem for the population of the city of Lima. Faced with this problem, there are alternatives for improvements in vehicular traffic that minimize the time lost. This problem is evident in many avenues and streets of this city; Especially during rush hour traffic. To that extent, the purpose of this thesis provides a solution to be applied in Alfredo Benavides Avenue between sections of the Higuereta oval and Velasco Astete avenue. As well, the purpose is to apply the offer management of the demand framed in the optimization and coordination of traffic light phases and to the improvement of traffic indicators, such as: the saturation degrees, the service levels, waiting delays and traffic light cycles at intersections. For this purpose, we use the software for traffic simulation, the Synchro 8 at mesoscopic level, which allows modeling the existing situation for the analysis of the current problem and subsequent solution proposal. Consequently, this thesis will evaluate the vehicular behavior of the network studied, through the HCM methodology where it does not consider cyclists and pedestrians. Finally, the proposed solution indicates that if it is possible to optimize and improve vehicular congestion of the section under study. This without altering, exceedingly, the infrastructure or generating higher costs of implementation on the road.
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Perez, Vargas Daniela Michelle, and Baltazar Jorge Enrique Yauyo. "Replanteo físico y operacional de la rotonda monitor ubicada en el distrito de Santiago de Surco para mejorar su eficiencia y seguridad vial." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/653423.

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La investigación presenta un nuevo diseño de rotondas llamado turbo rotondas, estos tipos de rotondas se adoptan, debido a que las glorietas convencionales multicarril se encuentran relacionadas con problemas como lo son el comportamiento de los conductores en la entrada, carril circulatorio y zonas de salida de la rotonda; donde se observa el cambio e invasión de los carriles sin respetar las marcas divisorias de carril lo que genera mayor velocidad. Las turbo rotondas a comparación de las rotondas convencionales, poseen beneficios operativos y de seguridad, gracias a que tienen separadores de carril cuya principal función es de restringir los cambios de carril o malas maniobras de los conductores, reducir la velocidad y los puntos de conflictos. Para el caso de estudio se eligió a la rotonda Monitor por la congestión vehicular que presenta, la mala operación de la rotonda y la alta tasa de accidentes de tránsito, por lo que se plantea un rediseño físico y operacional mediante una turbo rotonda, donde se evaluará los niveles de servicio, las demoras y el nivel de seguridad a través de una microsimulación mediante el software Vissim 9 entre la rotonda actual y la propuesta. Finalmente, después de realizar varias corridas al programa se llega a la conclusión de que el replanteo físico y operacional de la rotonda Monitor Huáscar, a través de la Turbo Rotonda tipo rotor beneficia a los usuarios mejorando el nivel de servicio de F a C. Esto quiere decir, que las demoras y los tiempos de viaje se reducen significativamente. Además, de mejorar la seguridad vial reduciendo el número de puntos de conflicto.
The research presents a new roundabout design called turbo roundabouts, these types of roundabouts are adopted, due to specific multi-lane roundabouts are related to problems such as the behavior of drivers at the entrance, circulatory lane and exit areas of the roundabout where the change and invasion of the lanes is observed without respect the lane divisions marks which generates greater speed. The turbo roundabouts to the comparison of compact roundabouts, the features operational and safety benefits, thanks to the fact that they have rail separators whose main function is restricted lane changes or bad driver jaws, reduce speed and conflict points . In the case of the study, the roundabout Monitor was chosen because of the traffic congestion that shows inefficiency in the operation of the roundabout and high traffic accident rate, so a physical and operational redesign is proposed through a turbo roundabout, where it is evaluated service levels, delays and security level through microsimulation using Vissim 9 software between the current roundabout and the proposed one. Finally, after making several runs to the program, it is concluded that the physical and operational replacement of the Huáscar Monitor roundabout, through the Rotor-type Turbo Roundabout, benefits users by improving the service level from F to C. This wants That is, delays and travel times are significantly reduced. In addition, improve road safety by reducing the number of conflict points.
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Moreano, Quiroz Percy Josue, and Santos Juneor Varoni Trejo. "Propuesta de mejora vial, de la intersección Av. alameda sur con av. Alameda San Marcos en el distrito de Chorrillos, para reducir la congestión vehicular." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/653503.

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La investigación comprende el análisis de las condiciones del tráfico actual y futuro en la intersección Av. Alameda Sur con Av. Alameda San Marcos del distrito de Chorrillos. El análisis se enfoca en la geometría, señalización y semaforización de la intersección con el objetivo de plantear una propuesta de mejora vial para mitigar el congestionamiento vehicular, alcanzando como resultado la mejora del nivel del servicio. La investigación inicia con la descripción de la problemática existente. En base a ello se formula una hipótesis y se determina como objetivo plantear una propuesta de mejora del diseño geométrico, señalización y semaforización que mitigue el congestionamiento vehicular. Con el propósito de realizar la evaluación, se utilizó el programa Vissim 9, comparable con la metodología Highway Capacity Manual (HCM 2010), a fin de modelar la intersección. Luego, se calibró y validó el modelo por medio de las longitudes de cola obtenidas en campo con la finalidad que el modelo se asemeje lo más cercano posible a la realidad. A fin de reducir la congestión, se propusieron mejoras en la geometría, señalización y, por medio del programa Synchro 10, una optimización del ciclo semafórico. Seguidamente, se realizaron dos simulaciones de la intersección proyectada a 10 años con el propósito de definir los niveles de servicio: la primera manteniendo condiciones actuales y la segunda incluyendo la propuesta de mejora. En la etapa de análisis, los resultados demostraron que la propuesta mejoró el nivel de servicio de “F” a “D”, y redujo en 61.5% la longitud de cola promedio en la intersección.
The research includes the analysis of current and future traffic conditions at the intersection of Av. Alameda Sur with Av. Alameda San Marcos in the Chorrillos district. The analysis focuses on the geometry, signaling and signaling of the intersection with the objective of proposing a proposal for road improvement to mitigate vehicular congestion, achieving as a result the improvement of the service level. The research begins with the description of the existing problem. Based on this, a hypothesis is formulated, and the objective is to present a proposal to improve the geometric design, signaling and traffic lights to mitigate vehicular congestion. To carry out the evaluation, the Vissim 9 program, comparable to the Highway Capacity Manual methodology (HCM 2010), was used to model the intersection. Then, the model was calibrated and validated by means of the queue lengths recorded in the field so that the model resembles as closely as possible to reality. To reduce congestion, improvements in geometry, signaling and, through the Synchro 10 program, an optimization of the signal cycle were proposed. Subsequently, two microsimulations of the intersection projected to 10 years were carried out to define the service levels: the first one maintaining current conditions and the second one including the improvement proposal. In the analysis stage, the results showed that the proposal improved the service level from “F” to “D” and reduced the average queue length at the intersection by 61.5%.
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Jornet, Gibert Montsant. "Conducció sota els efectes de l’alcohol: el paper de la personalitat i la Teoria de la Conducta Planificada = Driving under the influence of alcohol: the role of personality and the Theory of Planned Behaviour." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/666371.

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La conducció sota els efectes de l’alcohol és un dels principals factors de risc de la sinistralitat viària. Malgrat els esforços de governs i institucions per reduir les xifres de sinistralitat, el nombre d’accidents de trànsit relacionats amb el consum d’alcohol s’ha mantingut estable en els darrers anys. La reforma del Codi Penal en matèria de trànsit del 2007 ha suposat un increment dels penats per conducció temerària. La conducció sota la influència de begudes alcohòliques representa aproximadament el 50% de les condemnes per delictes contra la seguretat del trànsit. Conèixer quines són les característiques psicològiques més rellevants relacionades amb aquest delicte suposaria un pas endavant en la prevenció i la intervenció en seguretat viària, i facilitaria el disseny d’estratègies enfocades a prevenir aquesta conducta i la reincidència delictiva. Aquesta tesi s’estructura en dos grans objectius, que es desenvolupen en els estudis 1 i 2. L’estudi 1 pretén identificar els factors de risc de la conducció sota els efectes de l’alcohol, i conèixer quines són les característiques psicològiques dels penats per aquest delicte. En aquest estudi comparem les característiques de personalitat i actitudinals d’un grup de penats per conducció sota els efectes de l’alcohol i un grup de conductors control. Una anàlisi descriptiva dels resultats no revela diferències significatives entre els dos grups en cap de les dimensions de personalitat avaluades, mentre que el grup de penats mostra més actituds antisocials. Malgrat això, els resultats de l’anàlisi de regressió indiquen que la conducció sota els efectes de l’alcohol es relaciona amb un alt neuroticisme, baixes puntuacions en responsabilitat i fortes actituds antisocials. Els resultats d’aquest estudi mostren una alta coincidència entre el perfil psicològic de la conducció sota els efectes de l’alcohol, la conducta antisocial general, i l’abús d’alcohol. Aquests resultats s’haurien de tenir en compte en el desenvolupament de programes de prevenció, identificant aquells conductors amb un major risc de conduir sota els efectes de l’alcohol, així com aquells perfils amb una major resistència al canvi. D’altra banda, les actituds antisocials són un bon target a tenir en compte en els programes d’intervenció en conductors penats per conducció sota els efectes de l’alcohol. L’estudi 2 té com a objectiu avaluar la utilitat de la Teoria de la Conducta Planificada (TPB) per a predir intenció de conduir sota els efectes de l’alcohol. La TPB és un model àmpliament utilitzat en la recerca de la conducció de risc. En aquest estudi ens proposem posar a prova la TPB per a predir intenció de conduir havent begut en un grup de penats per conducció sota els efectes de l’alcohol complint una pena de presó, un grup de penats per conducció sota els efectes de l’alcohol complint una pena substitutiva a la presó, i un grup de conductors control. D’altra banda, ens proposem millorar aquest model incloent aquelles variables de personalitat i actitudinals que s’han relacionat amb la conducta antisocial i la conducció de risc. Els resultats d’aquest estudi mostren que els components de la TPB són capaços d’explicar entre un 20% i un 57% de la variància en intenció de conduir sota els efectes de l’alcohol, en línia amb els resultats d’altres estudis amb característiques similars. El component amb una major influència en la intenció és el control conductual percebut. La personalitat no representa una aportació rellevant en el model. Aquests resultats posen de manifest la necessitat d’incloure el control percebut dels conductors en les intervencions centrades en evitar la conducció sota els efectes de l’alcohol. També, suggereixen que la intenció de conduir sota els efectes de l’alcohol no està influïda directament per característiques de personalitat concretes, i obren noves línies de recerca centrades en explorar els mecanismes pels quals la personalitat influeix en la conducció sota els efectes de l’alcohol.
Driving under the influence of alcohol is one of the main risks of road accidents. Knowing which are the most relevant psychological characteristics related to this crime would be a step forward in the prevention and intervention in traffic safety, and would help in the design of strategies aiming to prevent this behaviour and the recidivism. This thesis is structured in two main objectives, which are developed in studies 1 and 2. Study 1 aims to identify the risk factors for driving under the influence of alcohol, and to determine the psychological characteristics of those who have been convicted for this crime. In this study we compare personality and attitudes of a group of DUI (driving under the influence of alcohol) offenders and a group of control drivers. A descriptive analysis does not show significant differences between the two groups in any of the personality dimensions, while offenders show more antisocial attitudes. However, results of the regression analysis indicate that driving under the influence of alcohol is related to a high neuroticism, low scores in conscientiousness and strong antisocial attitudes. Study 2 aims to evaluate the usefulness of the Theory of Planned Behaviour (TPB) to predict the intention to drive under the influence of alcohol. Our aim is to test the TPB to predict drunk driving intention in a group of DUI offenders serving a prison sentence, a group of drivers following a diversion programme as an alternative sanction for a DUI offense, and a group of control drivers. On the other hand, we aimed to improve the TPB model, including those personality and attitudinal variables that have been linked to antisocial behaviour and risky driving. Results of this study show that the TPB components are capable of explaining between 20% and 57% of the variance in intention to drive under the influence of alcohol, in line with the results of other studies with similar characteristics. The component with a greater influence on intention is perceived behavioural control. Personality does not represent a significant contribution to the models. The final part discusses the implications of these findings in the design and improvement of targeted programmes focused on preventing drunk driving and intervention programmes for DUI offenders.

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19

Aroni, Yallercco Tony, and Cisneros Marco Daniel Mantarí. "Evaluación e implementación de estrategias para reducir el riesgo de atropellamientos en la intersección semaforizada de las Avenidas José Matías Manzanilla y J.J. Elías, de la ciudad de Ica, Perú." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2021. http://hdl.handle.net/10757/655740.

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La siguiente Tesis de investigación propone implementar medidas de acoplamiento de la infraestructura sobre el diseño actual de la geometría vial en la intersección de la Av. José Matías Manzanilla con Av. J.J. Elías de la ciudad de Ica; con la finalidad de mejorar el desempeño de la seguridad vial urbana de peatones y usuarios vulnerables. Las propuestas de dichas mejoras, están basadas en las recomendaciones de la Federal Highway Administration – FHWA de los Estados Unidos, para la implementación de elementos de seguridad vial en intersecciones con semáforo. Para conocer el nivel de riesgo a la seguridad vial en el área de estudio, se determinaron la hora de máxima demanda para los peatones que transitan por estas avenidas, mediante recolección de datos volumétricos del flujo de tráfico multimodal. Además, se incorporaron al análisis, la información de la geometría de la intersección y las características actuales de los dispositivos de control semafórico y de señalización horizontal y vertical. Con el apoyo en la información recopilada, se implementaron la evaluación del desempeño de la situación actual de la seguridad vial con el programa de acceso libre VIDA-IRAP. Los resultados obtenidos indicaron serios cuestionamientos a la seguridad vial de los usuarios vulnerables, que serían superados con la implementación de las estrategias recomendadas en el presente trabajo. Asimismo, las recomendaciones propuestas en los puntos 4.2.5. y 4.2.6. del Capítulo 4 respectivamente, desarrollan un listado de verificación del alojamiento de peatones en las intersecciones con semáforo que puedan ser recogidas en una actualización de Manual de Seguridad Vial (MTC, MSV; 2017); así como, una serie de técnicas y procedimientos de levantamiento de información y clasificación de datos de los sitios en estudio, para aplicar modificaciones operacionales de semaforización, que favorezcan a la seguridad peatonal y que puedan ser recogidas en una actualización de Manual de Dispositivos de Control del Tránsito Automotor para Calles y Carreteras (MTC; MDCTACC, 2016).
The following research proposes to implement measures of coupling of the infrastructure on the current design of the road geometry at the intersection of Av. José Matías Manzanilla with Av. J.J. Elías in Ica city; in order to improve the performance of urban road safety for pedestrians and vulnerable users. The proposals for these improvements are based on the recommendations of the Federal Highway Administration - FHWA of the United States, for the implementation of road safety elements in signalized intersections. In order to know the level of risk to road safety in the study area, the rush hour demand was determined for pedestrians passing through these avenues, by collecting volumetric data on the multimodal traffic flow. In addition, the information on the geometry of the intersection and the current characteristics of signal control devices and horizontal and vertical signaling were incorporated into the analysis. With the support of the information collected, the performance evaluation of the current situation of road safety was implemented with the free access program VIDA-IRAP. The results obtained indicated serious questions to the road safety of vulnerable users, which would be overcome with the implementation of the strategies recommended in this work. Likewise, the recommendations proposed in points 4.2.5. and 4.2.6. of Chapter 4 respectively, develop a checklist of pedestrian accommodation at signalized intersections, that can be included in an update of the Road Safety Manual (MTC, MSV; 2017); as well as a series of techniques and procedures for collecting information and classifying data from the sites under study, to apply operational modifications signal timing, which favor pedestrian safety and which can be included in an update of the Control Devices Manual of Automotive Traffic for Streets and Highways (MTC; MDCTACC, 2016).
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20

Bel-Piñana, Paula. "Public-Private Partnerships in Roads: Economic and Policy Analyses." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/663251.

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In recent decades, public-private partnerships has converted in an alternative way of providing transport infrastructures that has been traditional delivered by public sector. Between 1990 and 2017, governments all over the world have awarded more than 1600 PPPs transport infrastructure. However, there are some aspects that affect public-private partnerships that has not been analyzed and which could facilitate the study of their economic impact. This Thesis analyses public-private partnerships in road infrastructures. The context for the analysis is Spain, both because of its pioneering nature in the extension of such public-private partnerships and because of the undisputed weight of the road infrastructure industry in the international context. The thesis is structured in five chapters. The first chapter is the introduction and examines the role of PPPs in road infrastructures and the road PPPs in Spain’s toll motorways. The second chapter is divided into two sections. The first part of the chapter analyze whether the allocation of risks that has been carried out in Spain and other countries complies with the predictions of contract theory. To this end, the framework of institutional and economic relations between the state and private concessionaires is reviewed in detail. The purpose of this case analysis is to identify the main limitations of these models and to delineate those aspects that have a significant influence on the incentives of the different parties, the efficiency of the contract, the financial evolution of the concession and its impact on public finances, taxpayers and users. Additionally, good regulatory practices are suggested in the concession business, which make it possible to take advantage of the benefits that private participation in road infrastructure projects can bring. The second part of the chapter examines whether the financial downturn experienced by most concessions awarded at the beginning of the new millennium can be attributed to Spain’s particular model of risk sharing and guarantees. This analysis intends to shed light on the debate on possible solutions to the crisis in the sector. Chapter third quantify and evaluate the social and distributive impact of one of the last political renegotiations, which took place in 1997 between the state and the concessionary in Spain. Specifically, the case of the renegotiation of the concession contracts for the AP-7 motorway in its sections between Tarragona-Valencia and Valencia-Alicante is illustrated. In order to carry out this study, the change in well- being resulting from the renegotiations has been calculated. This approximation allows us to compare the real status quo situation with renegotiation, with the alternative that would have been not to renegotiate and delimit the monetary impact of such renegotiations for each of the agents involved and for the added social well- being. The fourth chapter analyses whether the type of management on high-capacity roads has any impact on road safety. We use the Spanish case as an analysis model. Spain’s mixed composition of high-capacity roads is an excellent opportunity to empirically test whether private road management through PPP contracts offers better quality than traditional provision. To this end, we apply different econometric techniques based on tallying data on a data panel for the period 2008-2012. Lastly, chapter five extracts the most important conclusions from the previous chapters and provide some public policy recommendations based on them.

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Dubé, Mathieu. "Étude du mécanisme d’augmentation de la relâche virale par la protéine Vpu du VIH-1." Thèse, 2011. http://hdl.handle.net/1866/5503.

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Les différentes protéines accessoires du VIH-1, l’agent étiologique du SIDA, optimisent la réplication et la propagation du virus in vivo. Parmi ces dernières figure Vpu, l’antagoniste du facteur de restriction nommé Tetherin qui prévient la relâche des particules virales à partir de la surface de cellules infectées. En diminuant son expression de surface, Vpu prévient l’incorporation de ce facteur de restriction dans la particule virale en formation et conséquemment, empêche la formation d’une ancre protéique reliant le virus mature à la membrane plasmique de la cellule infectée. La mécanistique sous-jacente n’était cependant pas connue. Cette présente thèse relate nos travaux exécutés afin d’élucider la dynamique des mécanismes cellulaires responsables de cet antagonisme. Une approche de mutagénèse dirigée a d’abord permis d’identifier deux régions contenant des déterminants de la localisation de Vpu dans le réseau trans-Golgi (RTG), puis de démontrer la relation existante entre cette distribution et l’augmentation de la relâche des particules virales. Des expériences subséquentes de marquage métabolique suivi d’une chasse exécutées dans des systèmes cellulaires où Tetherin est exprimée de façon endogène ont suggéré le caractère dispensable de l’induction par Vpu de la dégradation du facteur de restriction lors de son antagonisme. En revanche, une approche de réexpression de Tetherin conduite en cytométrie en flux, confirmée en microscopie confocale, a mis en évidence une séquestration de Tetherin dans le RTG en présence de Vpu, phénomène qui s’est avéré nécessiter l’interaction entre les deux protéines. L’usage d’un système d’expression de Vpu inductible conjugué à des techniques de cytométrie en flux nous a permis d’apprécier l’effet majeur de Vpu sur la Tetherin néo-synthétisée et plus mineur sur la Tetherin de surface. En présence de Vpu, la séquestration intracellulaire de la Tetherin néo-synthétisée et la légère accélération de l’internalisation naturelle de celle en surface se sont avérées suffisantes à la réduction de son expression globale à la membrane plasmique et ce, à temps pour l’initiation du processus de relâche virale. À la lumière de nos résultats, nous proposons un modèle où la séquestration de la Tetherin néo-synthétisée dans le RTG préviendrait le réapprovisionnement de Tetherin en surface qui, combinée avec l’internalisation naturelle de Tetherin à partir de la membrane plasmique, imposerait l’établissement d’un nouvel équilibre de Tetherin incompatible avec une restriction de la relâche des particules virales. Cette thèse nous a donc permis d’identifier un processus par lequel Vpu augmente la sécrétion de virus matures et établit une base mécanistique nécessaire à la compréhension de la contribution de Vpu à la propagation et à la pathogénèse du virus, ce qui pourrait mener à l’élaboration d’une stratégie visant à contrer l’effet de cette protéine virale.
All accessory proteins of HIV-1, the ethiologic agent of AIDS, are thought to optimize viral replication and propagation in vivo. Among them, Vpu antagonizes Tetherin, a cellular factor that inhibits viral particle release. Downregulation of cell-surface Tetherin by Vpu is believed to prevent incorporation of this restriction factor into nascent viral particles, which would impede the formation of a Tetherin-derived protein anchor that bridges the virus to the plasma membrane of the infected cell. This thesis presents our studies on cellular mechanisms governing Tetherin antagonism by Vpu. A directed mutagenesis approach first identified two regions encompassing determinants of the localization of Vpu in the trans-Golgi network, and it correlated this intracellular distribution with enhanced release viral particle. Pulse-chase experiments in cellular systems wherein Tetherin was endogenously expressed showed that Vpu-induced Tetherin degradation is dispensable for restriction. In contrast, both a flow cytometry-based Tetherin re-expression assay and confocal microscopy analyses demonstrated that Vpu-mediated sequestration of Tetherin in the trans-Golgi network, a phenomenon that appeared to be triggered by the transmembrane association of the two proteins, was necessary for release inhibition. Vpu inducible expression in flow cytometry-based experiments provided evidence for an optimal antagonism of Tetherin at 6h after Vpu expression, following the interruption of Tetherin re-supply and a to the modest acceleration of the natural clearance of surface-localized Tetherin. Our work supports a model in which Tetherin sequestration in the trans-Golgi network prevents its re-supply, which, combined with its clearance from the surface, imposes a new equilibrium at the plasma membrane that is incompatible with the restriction of viral particle release. Overall, this thesis sheds light on the processes by which Vpu enhances the secretion of mature viruses and it establishes a mechanistic basis that could serve as starting point for the development of strategies aimed at interfering with Tetherin functions.

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Lierkamp, Darren University of Ballarat. "A New ramp metering control algorithm for optimizing freeway travel times." 2006. http://archimedes.ballarat.edu.au:8080/vital/access/HandleResolver/1959.17/12726.

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"In many cities around the world traffic congestion has been increasing faster than can be dealt with by new road construction. To resolve this problem traffic management devices and technology such as ramp meters are increasingly being utilized."--leaf 1.
Masters of Information Technology

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Lierkamp, Darren. "A New ramp metering control algorithm for optimizing freeway travel times." 2006. http://archimedes.ballarat.edu.au:8080/vital/access/HandleResolver/1959.17/14605.

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"In many cities around the world traffic congestion has been increasing faster than can be dealt with by new road construction. To resolve this problem traffic management devices and technology such as ramp meters are increasingly being utilized."--leaf 1.
Masters of Information Technology

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Teh, Anselm. "Providing quality of service for realtime traffic in heterogeneous wireless infrastructure networks." 2009. http://arrow.unisa.edu.au/vital/access/manager/Repository/unisa:41467.

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In recent years, there has been a rapid growth in deployment and usage of realtime network applications, such as Voice-over-IP, video calls/video conferencing, live network seminars, and networked gaming. The continued increase in the popularity of realtime applications requires a more intense focus on the provision of strict guarantees for Quality of Service (QoS) parameters such as delay, jitter and packet loss in access networks. At the same time, wireless networking technologies have become increasingly popular with a wide array of devices such as laptop computers, Personal Digital Assistants (PDAs), and cellular phones being sold with built-in WiFi and WiMAX interfaces. For realtime applications to be popular over wireless networks, simple, robust and effective QoS mechanisms suited for a variety of heterogeneous wireless networks must be devised. Implementing the same QoS mechanisms across multiple neighbouring networks aids seamless handover by ensuring that a flow will be treated in the same way, both before and after handover. To provide guaranteed QoS, an access network should limit load using an admission control algorithm. In this research, we propose a method to provide effective admission control for variable bit rate realtime flows, based on the Central Limit Theorem. Our objective is to estimate the percentage of packets that will be delayed beyond a predefined delay threshold, based on the mean and variance of all the flows in the system. Any flow that will increase the percentage of delayed packets beyond an acceptable threshold can then be rejected. Using simulations we have shown that the proposed method provides a very effective control of the total system load, guaranteeing the QoS for a set of accepted flows with negligible reductions in the system throughput. To ensure that flow data is transmitted according to the QoS requirements of a flow, a scheduling algorithm must handle data intelligently. We propose methods to allow more efficient scheduling by utilising existing Medium Access Control mechanisms to exchange flow information. We also propose a method to determine the delay-dependent "value" of a packet based on the QoS requirements of the flow. Using this value in scheduling is shown to increase the number of packets sent before a predetermined deadline. We propose a measure of fairness in scheduling that is calculated according to how well each flow's QoS requirements are met. We then introduce a novel scheduling paradigm, Delay Loss Controlled-Earliest Deadline First (DLC-EDF), which is shown to provide better QoS for all flows compared to other scheduling mechanisms studied. We then study the performance of our admission control and scheduling methods working together, and propose a feedback mechanism that allows the admission control threshold to be tuned to maximise the efficient usage of available bandwidth in the network, while ensuring that the QoS requirements of all realtime flows are met. We also examine heterogeneous/vertical handover, providing an overview of the technologies supporting seamless handover. The issues studied in this area include a method of using the Signal to Noise Ratio to trigger handover in heterogeneous networks and QoS Mapping between heterogeneous networks. Our proposed method of QoS mapping establishes the minimum set of QoS parameters applicable to individual flows, and then maps these parameters into system parameter formats for both 802.11e and 802.16e networks.

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Wei, Tzu-Shun, and 魏子順. "Virtual Path Assignment and Virual Connecting Routing in ATM Networks with Multiple Traffic Classes." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/28388699034939567499.

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碩士
國立台灣工業技術學院
電子工程技術研究所
85
AbstractThe use of ATM network could transfer multiple class of traffic. This advantage is the main reason why it's so welcome. How to manage it efficiently and allocate capable bandwidth to VP to help out finding the best VC route so that it's feature could fit in different application would be the direct challenge the one who manage and ATM network have to face.In this thesis the main point we want to investigate is when transfer traffics of different QoS in ATM network in order to minimize the total call blocking rate subject to call set-up time constrains what process should we take in determine virtual path assignment and virtual connection routing. In addition, when transfer traffics of different QoS in ATM network there are many methods to manage VP. Here we choose two different one (1) separate traffic management method and (2) joint traffic management method. We will transfer the problems of the management of VP assignment and VC routing to mathematics models of nonlinear combinatorial optimization problems. The basic approach to the algorithm development is Lagrangean Relaxation. According to proposed algorithm that result in some actual networks test, using joint traffic management's method total call blocking rate would be more efficient than separate traffic management method.

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Orthwein, Alexandre. "Analyse du trafic et de la distribution intracellulaire de la protéine Gag du VIH-1 dans les cellules HEK 293T : importance de l'efficacité de la relâche virale." Thèse, 2007. http://hdl.handle.net/1866/15171.

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Dissertations / Theses on the topic 'Viral traffic'

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