Academic literature on the topic 'Viral traffic'
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Journal articles on the topic "Viral traffic"
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Luethy, Lauren N., and Julie K. Pfeiffer. "Viral Infection Brings Mitochondrial Traffic to a Standstill." Cell Host & Microbe 11, no. 5 (May 2012): 420–21. http://dx.doi.org/10.1016/j.chom.2012.05.001.
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Enserink, M. "AVIAN INFLUENZA: Keeping Track of Viral Air Traffic." Science 310, no. 5747 (October 21, 2005): 428. http://dx.doi.org/10.1126/science.310.5747.428.
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Morse, Stephen S. "Emerging Viruses: Defining the Rules for Viral Traffic." Perspectives in Biology and Medicine 34, no. 3 (1991): 387–409. http://dx.doi.org/10.1353/pbm.1991.0038.
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Roman, Laura M., and Henrik Garoff. "Revelation through exploitation: the viral model for intracellular traffic." Trends in Biochemical Sciences 10, no. 11 (November 1985): 428–32. http://dx.doi.org/10.1016/0968-0004(85)90024-6.
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Lidsky, Peter V., Stanleyson Hato, Maryana V. Bardina, Alexei G. Aminev, Ann C. Palmenberg, Eugene V. Sheval, Vladimir Y. Polyakov, Frank J. M. van Kuppeveld, and Vadim I. Agol. "Nucleocytoplasmic Traffic Disorder Induced by Cardioviruses." Journal of Virology 80, no. 6 (March 15, 2006): 2705–17. http://dx.doi.org/10.1128/jvi.80.6.2705-2717.2006.
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ABSTRACT Some picornaviruses, for example, poliovirus, increase bidirectional permeability of the nuclear envelope and suppress active nucleocytoplasmic transport. These activities require the viral protease 2Apro. Here, we studied nucleocytoplasmic traffic in cells infected with encephalomyocarditis virus (EMCV; a cardiovirus), which lacks the poliovirus 2Apro-related protein. EMCV similarly enhanced bidirectional nucleocytoplasmic traffic. By using the fluorescent “Timer” protein, which contains a nuclear localization signal, we showed that the cytoplasmic accumulation of nuclear proteins in infected cells was largely due to the nuclear efflux of “old” proteins rather than impaired active nuclear import of newly synthesized molecules. The nuclear envelope of digitonin-treated EMCV-infected cells permitted rapid efflux of a nuclear marker protein. Inhibitors of poliovirus 2Apro did not prevent the EMCV-induced efflux. Extracts from EMCV-infected cells and products of in vitro translation of viral RNAs contained an activity increasing permeability of the nuclear envelope of uninfected cells. This activity depended on the expression of the viral leader protein. Mutations disrupting the zinc finger motif of this protein abolished its efflux-inducing ability. Inactivation of the L protein phosphorylation site (Thr47→Ala) resulted in a delayed efflux, while a phosphorylation-mimicking (Thr47→Asp) replacement did not significantly impair the efflux-inducing ability. Such activity of extracts from EMCV-infected cells was suppressed by the protein kinase inhibitor staurosporine. As evidenced by electron microscopy, cardiovirus infection resulted in alteration of the nuclear pores, but it did not trigger degradation of the nucleoporins known to be degraded in the poliovirus-infected cells. Thus, two groups of picornaviruses, enteroviruses and cardioviruses, similarly alter the nucleocytoplasmic traffic but achieve this by strikingly different mechanisms.
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Suikkanen, Sanna, Tuula Aaltonen, Marjukka Nevalainen, Outi Välilehto, Laura Lindholm, Matti Vuento, and Maija Vihinen-Ranta. "Exploitation of Microtubule Cytoskeleton and Dynein during Parvoviral Traffic toward the Nucleus." Journal of Virology 77, no. 19 (October 1, 2003): 10270–79. http://dx.doi.org/10.1128/jvi.77.19.10270-10279.2003.
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ABSTRACT Canine parvovirus (CPV), a model virus for the study of parvoviral entry, enters host cells by receptor-mediated endocytosis, escapes from endosomal vesicles to the cytosol, and then replicates in the nucleus. We examined the role of the microtubule (MT)-mediated cytoplasmic trafficking of viral particles toward the nucleus. Immunofluorescence and immunoelectron microscopy showed that capsids were transported through the cytoplasm into the nucleus after cytoplasmic microinjection but that in the presence of MT-depolymerizing agents, viral capsids were unable to reach the nucleus. The nuclear accumulation of capsids was also reduced by microinjection of an anti-dynein antibody. Moreover, electron microscopy and light microscopy experiments demonstrated that viral capsids associate with tubulin and dynein in vitro. Coprecipitation studies indicated that viral capsids interact with dynein. When the cytoplasmic transport process was studied in living cells by microinjecting fluorescently labeled capsids into the cytoplasm of cells containing fluorescent tubulin, capsids were found in close contact with MTs. These results suggest that intact MTs and the motor protein dynein are required for the cytoplasmic transport of CPV capsids and contribute to the accumulation of the capsid in the nucleus.
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Haupt, Sophie, Graham H. Cowan, Angelika Ziegler, Alison G. Roberts, Karl J. Oparka, and Lesley Torrance. "Two Plant–Viral Movement Proteins Traffic in the Endocytic Recycling Pathway." Plant Cell 17, no. 1 (December 17, 2004): 164–81. http://dx.doi.org/10.1105/tpc.104.027821.
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Shimizu, Kenta, Kumiko Yoshimatsu, Takaaki Koma, Shumpei P. Yasuda, and Jiro Arikawa. "Role of nucleocapsid protein of hantaviruses in intracellular traffic of viral glycoproteins." Virus Research 178, no. 2 (December 2013): 349–56. http://dx.doi.org/10.1016/j.virusres.2013.09.022.
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Ikonen, E., R. G. Parton, F. Lafont, and K. Simons. "Analysis of the role of p200-containing vesicles in post-Golgi traffic." Molecular Biology of the Cell 7, no. 6 (June 1996): 961–74. http://dx.doi.org/10.1091/mbc.7.6.961.
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p200 is a cytoplasmic protein that associates with vesicles budding from the trans-golgi network (TGN). The protein was identified by a monoclonal antibody AD7. We have used this antibody to analyze whether p200 functions in exocytic transport from the TGN to the apical or basolateral plasma membrane in Madin-Darby canine kidney cells. We found that transport of the viral marker proteins, influenza hemagglutinin (HA) to the apical surface or vesicular stomatitis virus glycoprotein (VSV G) to the basolateral surface in streptolysin O-permeabilized cells was not affected when p200 was depleted from both the membranes and the cytosol. When vesicles isolated from perforated cells were analyzed by equilibrium density gradient centrifugation, the p200 immunoreactive membranes did not comigrate with either the apical vesicle marker HA or the basolateral vesicle marker VSV G. Immunoelectron microscopy of perforated and double-labeled cells showed that the p200 positive vesicular profiles were not labeled by antibodies to HA or VSV G when the viral proteins were accumulated in the TGN. Furthermore, the p200-decorated vesicles were more electron dense than those labeled with the viral antibodies. Together, these results suggest that p200 does not function in the transport pathways that carry HA from the TGN to the apical surface or VSV G from the TGN to the basolateral surface.
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Jing, Peng, Farzin Haque, Dan Shu, Carlo Montemagno, and Peixuan Guo. "One-Way Traffic of a Viral Motor Channel for Double-Stranded DNA Translocation." Nano Letters 10, no. 9 (September 8, 2010): 3620–27. http://dx.doi.org/10.1021/nl101939e.
Full textDissertations / Theses on the topic "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 THTLV-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'infectionFoamy 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 viraleThe 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 SouzaTese (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 nucléoleThe 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 MTsThe 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.
Tesis
Books on the topic "Viral traffic"
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Castilla, Gustavo Ordoqui. Ley de tránsito y seguridad vial, 18,191. Montevideo, Uruguay: La Ley Uruguay, 2009.
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Spain. Tráfico, circulación y seguridad vial. Madrid: Ministerio del Interior, Dirección General de Tráfico, 1990.
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Isasi Ortiz de Barrón, Fernando, ed. Tráfico y seguridad vial. Cizur Menor (Navarra): Editorial Aranzadi, 2003.
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1960-, Linamen Karen Scalf, ed. Vital connections. Colorado Springs, CO]: LearningRx, 2012.
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Spain. Comisión Nacional de Seguridad de la Circulación Vial. Plan nacional de seguridad vial para el año 1991. Madrid: Dirección General de Tráfico, Ministerio del Interior, 1991.
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Juan Manuel Herrero de Egaña Espinosa de los Monteros. Ley de seguridad vial: Infracciones y sanciones : procedimiento sancionador. Pamplona: Aranzadi Editorial, 1992.
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León, Luis Carlos Rodríguez. Seguridad vial: Crónica de una reforma penal. Sevilla: Instituto Andaluz de Administración Pública, 2008.
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León, Luis Carlos Rodríguez. Seguridad vial: Crónica de una reforma penal. Sevilla: Instituto Andaluz de Administración Pública, 2008.
Find full textBook chapters on the topic "Viral traffic"
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Arias, C. F., D. Silva-Ayala, P. Isa, M. A. Díaz-Salinas, and S. López. "Rotavirus Attachment, Internalization, and Vesicular Traffic." In Viral Gastroenteritis, 103–19. Elsevier, 2016. http://dx.doi.org/10.1016/b978-0-12-802241-2.00006-7.
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"AIDS and Beyond: Defining the Rules for Viral Traffic." In AIDS, 23–48. University of California Press, 1992. http://dx.doi.org/10.1525/9780520912441-002.
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Roldan, Malu. "The Evolution of Web Marketing Practice." In Internet Marketing Research, 31–46. IGI Global, 2001. http://dx.doi.org/10.4018/978-1-878289-97-1.ch002.
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This chapter reviews the current state of Web marketing practice and presents a framework on the relationships among Web technology capabilities, marketing approach and customer orientation. We present a discussion of how Web technology capabilities — such as data, network reach, traceable traffic, portability, interactivity, and high-bandwidth transmission — enable different marketing approaches – specifically, matching, branding, customer experience, and viral marketing. The viability of these approaches is determined by how well they match the orientations of target customers – be it recreational, experiential, convenience, or economic. Propositions regarding the interaction between current practices and shopper orientations are presented as a basis for determining effective Web marketing practices.
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Armstrong, John. "The Role of Coastal Shipping in UK Transport: An Estimate of Comparative Traffic Movements in 1910." In The Vital Spark, 243–60. Liverpool University Press, 2009. http://dx.doi.org/10.5949/liverpool/9780986497308.003.0013.
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This chapter aims to estimate the amount of work performed by the coastal shipping industry in 1910 in relation to the rail and canal transport counterparts. It examines the services offered by the coastal industry in this period that the railway could not provide - such as ferrying to remote regions such as the Isle of Man, Isle of Wight, and Scottish islands. It compares and contrasts rail, canal, and coastal services by examining freight traffic; coal shipping; bills of entry; the Royal Commission on Canals; steamship company records; and Parliamentary papers to paint an accurate picture of the British transport industry in the pre-war period. It concludes that the shipping distribution in 1910 was fifty-nine percent coastal; thirty-nine percent rail, and two percent canal - and insists that coastal and canal shipping should not be paired together when discussing the rise of the railway as they were fundamentally distinct.
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Akhter, Shamim, Rahatur Rahman, and Ashfaqul Islam. "Neural Network (NN) Based Route Weight Computation for Bi-Directional Traffic Management System." In Deep Learning and Neural Networks, 750–65. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-0414-7.ch042.
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Low-cost, flexible, easily maintainable and secure traffic management support systems are in demand. Internet-based real time bi-directional communication provides significant benefits to monitor road traffic conditions. Dynamic route computation is a vital requirement to make the traffic management system more realistic and reliable. Therefore, an integrated approach with multiple data feeds and Backpropagation (BP) Neural Network (NN) with Levenberg-Marquardt (LM) optimization is applied to predict the road weights. The results indicate that the proposed traffic system/tool with NN based dynamic weights computation is much more effective to find the optimal routes. The BP NN with LM optimization achieves 96.67% accuracy.
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Jamal, Arshad, Hassan M. Al-Ahmadi, Farhan Muhammad Butt, Mudassir Iqbal, Meshal Almoshaogeh, and Sajid Ali. "Metaheuristics for Traffic Control and Optimization: Current Challenges and Prospects." In Search Algorithm - Essence of Optimization [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99395.
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Intelligent traffic control at signalized intersections in urban areas is vital for mitigating congestion and ensuring sustainable traffic operations. Poor traffic management at road intersections may lead to numerous issues such as increased fuel consumption, high emissions, low travel speeds, excessive delays, and vehicular stops. The methods employed for traffic signal control play a crucial role in evaluating the quality of traffic operations. Existing literature is abundant, with studies focusing on applying regression and probability-based methods for traffic light control. However, these methods have several shortcomings and can not be relied on for heterogeneous traffic conditions in complex urban networks. With rapid advances in communication and information technologies in recent years, various metaheuristics-based techniques have emerged on the horizon of signal control optimization for real-time intelligent traffic management. This study critically reviews the latest advancements in swarm intelligence and evolutionary techniques applied to traffic control and optimization in urban networks. The surveyed literature is classified according to the nature of the metaheuristic used, considered optimization objectives, and signal control parameters. The pros and cons of each method are also highlighted. The study provides current challenges, prospects, and outlook for future research based on gaps identified through a comprehensive literature review.
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Narayan, Valliammal, and Shanmugapriya D. "Big Data Analytics With Machine Learning and Deep Learning Methods for Detection of Anomalies in Network Traffic." In Handbook of Research on Machine and Deep Learning Applications for Cyber Security, 317–46. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-5225-9611-0.ch015.
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Information is vital for any organization to communicate through any network. The growth of internet utilization and the web users increased the cyber threats. Cyber-attacks in the network change the traffic flow of each system. Anomaly detection techniques have been developed for different types of cyber-attack or anomaly strategies. Conventional ADS protect information transferred through the network or cyber attackers. The stable prevention of anomalies by machine and deep-learning algorithms are applied for cyber-security. Big data solutions handle voluminous data in a short span of time. Big data management is the organization and manipulation of huge volumes of structured data, semi-structured data and unstructured data, but it does not handle a data imbalance problem during the training process. Big data-based machine and deep-learning algorithms for anomaly detection involve the classification of decision boundary between normal traffic flow and anomaly traffic flow. The performance of anomaly detection is efficiently increased by different algorithms.
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Alejos, Ana Vazquez, Paula Gómez Pérez, Manuel Garcia Sanchez, and Muhammad Dawood. "SimuMANET." In Technological Advancements and Applications in Mobile Ad-Hoc Networks, 408–43. IGI Global, 2012. http://dx.doi.org/10.4018/978-1-4666-0321-9.ch022.
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Simulation software in MANET research is vital. Such a tool provides a versatile mechanism to understand all the involved aspects of these particular systems, from the radio interface to the last communication layer. In this chapter, the authors present the SimuMANET project, a tool for both simulation and field tests purpose. It allows the deployment of wireless reconfigurable ad-hoc networks and MANETs, assisted by a real-time graphical user interface (GUI) for network traffic monitoring and management of radio electric features of the links established between the active network nodes. Due to a set of functionalities, such as GUI, network topology visualization, traffic and motion pattern configuration, and real-time network status analysis, the simulator introduced here becomes a valid tool for both research and education targets. Two scenarios with different types of motion and traffic are simulated using the SimuMANET tool, and the results are shown and commented to illustrate some capabilities of this software.
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Singh, Surabhi. "Student's Perception Towards Digital Learning for Skill Enhancement Programs." In Driving Traffic and Customer Activity Through Affiliate Marketing, 129–40. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-2656-8.ch009.
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Integrating digital activities into the broader strategy can be challenging for institutions providing online education they don't have yet strong digital capabilities. Indian educational institutes and universities lack in digital strategy skills to conceive a comprehensive plan for responding quickly to customer queries. Digital activities are an increasingly important part of any marketing and sales strategy. The ability to harness the power of digital platforms in delivery of educational courses cannot be denied. The organization should no longer be only concerned with simple act of providing digital course, but also with the innovative strategies through which they interact with students and create learning environment that is innovative, active, and challenging. Digital learning plays a vital role in the skills landscape.
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Rakhee and M. B. Srinivas. "A Soft Computing Approach for Data Routing in Hospital Area Networks (HAN)." In Hospital Management and Emergency Medicine, 71–83. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2451-0.ch004.
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This paper proposes an alternative model to deliver vital signs of patients in a hospital indoor environment where a large number of patients exist and the traffic generated rapidly changes over time using Body Area Network (BAN). The methodology for finding an optimal path includes a meta-heuristic that combines ANT Colony Optimization (ACO). The authors propose an ACO based framework for monitoring data originating from a BAN to improve network life, energy and load balancing of the overall network. Since the traffic generated by BANs on the network changes with time, finding a shortest path is important for Hospital Area Network. In this paper, the authors implemented an ACO based method and have carried out simulations using OMNeT++ to prove that the proposed method can find a better solution than conventional methods.
Conference papers on the topic "Viral traffic"
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Willis, P. J. "Emerging (IP) network traffic measurements and QoS implications." In IEE Seminar Telecommunications Quality of Service (QoS): Vital Ingredient for Success. IEE, 2003. http://dx.doi.org/10.1049/ic:20030200.
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Erdmann, Jakob, Robert Oertel, and Peter Wagner. "VITAL: A Simulation-Based Assessment of New Traffic Light Controls." In 2015 IEEE 18th International Conference on Intelligent Transportation Systems - (ITSC 2015). IEEE, 2015. http://dx.doi.org/10.1109/itsc.2015.12.
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Salaani, M. Kamel, Gary J. Heydinger, Paul A. Grygier, and W. Riley Garrott. "Transport Delay Compensation for the Image Generator Used in the National Advanced Driving Simulator." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42975.
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Despite the advances in computer graphics speed and quality, Image Generator (IG) delys are unavoidable due to the demanding details and complex scenarios run at the National Advanced Driving Simulator (NADS), in particular for urban traffic scenes. This paper introduces a new dynamic compensation algorithm for automotive driving simulator visual displays. The compensation method is based on an original approach used by NASA Ames Research Center for flight simulator applications. The compensator designed has nearly zero phase with well-maintained magnitued within the bandwidth. The algorithm has magnitude attenuation outside the bandwidth without altering the desired frequency response of the compensator. This paper discusses the compensation method, and presents results from the NADS showing drivers’ ability to steer the vehicle through corners without excessive overshoot resulting from human reactions to visual delays. The results demonstrate that compensating for visual delays for high-end driving simulators is vital for real-time fidelity.
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Bień, J., and M. Salamak. "Management of Bridge Structures – Challenges and Possibilities." In IABSE Symposium, Wroclaw 2020: Synergy of Culture and Civil Engineering – History and Challenges. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2020. http://dx.doi.org/10.2749/wroclaw.2020.0002.
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<p>Bridges are particularly vulnerable elements of transport infrastructures. In many cases, bridge structures may be subject to higher volumes of traffic and higher loads as well as more severe environmental conditions than it was designed. Sound procedures to ensure monitoring, quality control, and preventive maintenance systems are therefore vital. The paper presents main challenges and arriving possibilities in management of bridge structures, including: relationships between environment and bridge infrastructure, improvement of diagnostic technologies, advanced modelling of bridges in computer-based management systems, development of knowledge-based expert systems with application of artificial intelligence, applications of technology of Bridge Information Modelling (BrIM) with augmented and virtual reality techniques. Presented activities are focused on monitoring the safety of bridges for lowering the risk of an unexpected collapse significantly as well as on efficient maintenance of bridges as components of transport infrastructure − by means of integrated management systems.</p>
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Petelin, Stojan, Marko Perkovic, Peter Vidmar, and Katja Petelin. "Ship’s Engine Room Fire Modelling." In International Joint Power Generation Conference collocated with TurboExpo 2003. ASMEDC, 2003. http://dx.doi.org/10.1115/ijpgc2003-40176.
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When traffic accidents occur, transport systems can result in irreparable negative impacts on people as well as the environment. In maritime transport unexpected fire in the ship’s engine room represents a grave risk. Because such accidents are very often difficult to prevent, modelling of fire propagation bears a vital significance for setting up preventive measures and safety systems, whose task is the suppression of fire danger. The paper describes the CFAST computer model (Building and Fire Research Laboratory - National Institute of Standards and Technology), whose purpose is to solve the problem of fire propagation in a complex multi-compartment environment. In our example it was used in a concrete ship’s engine room, with a fire starting in the ship’s main propulsion engine. The application includes all elements that can be damaged in case of fire at different ventilation conditions of the ship’s engine room. By means of simulation, the analysis and presentation of physical parameters working upon exposed engine components was made.
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Makhoul, Nisrine. "Performance-based assessment of Nahr Al-Fidar bridge." In IABSE Symposium, Guimarães 2019: Towards a Resilient Built Environment Risk and Asset Management. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/guimaraes.2019.1237.
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<p>Nahr Al-Fidar Bridge is in Fidar village, which is located near Byblos City, Lebanon. The bridge reconstruction was carried out swiftly during 2006-2007, due to its importance as a vital commercial artery. Indeed, no traffic disruption is allowed on the bridge, since it leads to great economic losses. At the time being, even though the bridge has only accomplished about 10 years of its service life, it is being overloaded.</p><p>The paper aims to assess the performance of Nahr Al-Fidar bridge. To that purpose, first, the case bridge is introduced, and a visual inspection took place to identify current the state of the bridge. Second, the performance indicators are evaluated for this bridge, by means of the visual assessment, and the key performance indicators are assessed. The aim is to check if the bridge meets the pre-specified performance goals. Finally, a quality control plan is implemented for Nahr Al-Fidar bridge.</p>
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Collyer, Robert, Hasan Ahmed, Raj Navalurkar, and Dawn Harrison. "Urban Infrastructure: Design and Preservation - Brooklyn Bridge Rehabilitation Program." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.2753.
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<p>The Brooklyn Bridge is a National Historic Landmark and a New York City Landmark that has been in use for over 137 years. This is one of the most pictured bridge structures in the world, while being used as a critical and vital part of the infrastructure carrying over 105,000 vehicles per day. This paper addresses the engineering challenges/solutions related to the most current rehabilitation work being performed.</p><p>Contract 6 (2009 to 2017) represents a $650 million investment into the bridge to maintain it in a State of Good Repair. Work included deck replacement using accelerated bridge construction techniques and complete painting and steel repairs of the main span. A high-level traffic study and traffic simulations were developed to evaluate differing closure scenarios and their impacts on user costs and the traveling public.</p><p>Contract 6A (2017 to 2019) represents a $25 million investment in maintaining the historic and aesthetic integrity of the Brooklyn Bridge structures. Approximately, 30,000 SF of granite stone cladding will be replaced under this contract.</p><p>Contract 7 represents a $300 million investment that will address the rehabilitation of the historic arches on both sides of the main span and strengthening of the Towers. Construction is expected to begin in 2019.</p><p>Contract 8 represents a $250 million investment. It is in the planning phase and will address a new promenade enhancement (widening) over the Brooklyn Bridge.</p><p>This paper discusses how these engineering challenges were faced and resolved.</p>
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Pouryousef, Hamed, Paulo Teixeira, and Joseph Sussman. "Track Maintenance Scheduling and Its Interactions With Operations: Dedicated and Mixed High-Speed Rail (HSR) Scenarios." In 2010 Joint Rail Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/jrc2010-36125.
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HSRs are a complex system not only in terms of technical specifications, but also with respect to operations and maintenance over the track structure. Also, track structure is basically considered as the most important and costly railway asset. Its maintenance is vital to assure safety and operating practices are also of great importance to assure that a good level of service is provided. Considering track maintenance considerations over a new HSR line, one important and critical feature is the operational regime and the question of whether the line will be operated as mixed (passenger and freight) or dedicated only to passenger traffic. This can influence the maintenance patterns: preventive maintenance planning, maintenances scheduling and assignment issues. This will be different for the dedicated and mixed HSR traffic scenarios. In this research, the main approach is focused on the interactions between track maintenance planning and operational concerns and influences in these two scenarios. With this aim and within the current paper, a model of the preventive maintenance scheduling problem (PMSP) has been selected initially from Budai (2006) and then an upgraded revision of this model (Multi-segment assignment and scheduling of preventive maintenance problem) is introduced. Furthermore, the upgraded model of PMSP has been run over a given HSR line (Tehran-Qom HSR corridor in Iran) based on the comparison between the two scenarios of dedicated HSR and upgraded mixed HSR patterns. The main requirements, similarities and differences between these two scenarios are analyzed based on preventive maintenance scheduling and assignment requisites and interactions over the operating restrictions and considerations such as track possession patterns for maintenance activities. We conclude that decision making between these two scenarios through PMSP modeling are quite complicated and depends on the technical and operational specifications of the given HSR corridor, although some general comments on tradeoffs are possible.
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Wang, Zezhou, Xiang Liu, Yongxin Wang, Chaitanya Yavvari, Matthew Jablonski, Duminda Wijesekera, Brian Sykes, and Keith Holt. "Cyber Security Analysis for Advanced Train Control System (ATCS) in CTC Systems: Concepts and Methods." In 2019 Joint Rail Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/jrc2019-1236.
Full textAbstract:
Advanced Train Control System (ATCS) is a proprietary network protocol that expands the functionality and efficiency of Centralized Traffic Control (CTC) systems, by using radio communications (radio code line) for message delivery. However, end-to-end cyber security issues were not considered during initial design of ATCS in the 1980s. Meanwhile, the landscape of cyber-physical threats and vulnerabilities has changed dramatically over the last three decades. Even though cutting-edge systems like Positive Train Control (PTC) have adopted security properties such as integrity check and encryption methods, major railroads in North America still deploy legacy ATCS standards to maintain their individual CTC system. This paper first illustrated the background and general specifications of ATCS applications in North American railroads. The research team has noticed that few studies have systematically analyzed this topic since the emergence of ATCS, though its applications are still prevailing in the industry. Divided by both vital and non-vital operational scenarios, this paper presented case studies for ATCS-related vulnerabilities. We used a sender-receiver sequencing-based analysis and proposed a consequence-based simulation model to identify and further evaluate the cyber and physical risks under potential cyber-attacks. For the identified risk, the paper evaluated the likelihood based on the practical operational sequences, and recommended potential countermeasures for the industry to improve the security over the specific case. The research concluded that the fail-safe design in the ATCS systems would prevent the exploiting known security vulnerabilities which could result in unsafe train movements. However, the service disruptions under certain speculated attacks need further evaluation. At the end of this paper, we discussed our ongoing work for disruption evaluation in the wake of successful cyber attacks.
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Treacy, Mark, Danilo Della Ca', and Niculin Meng. "Recent advancements in the monitoring of bridges using “smart” components." In IABSE Congress, New York, New York 2019: The Evolving Metropolis. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/newyork.2019.0811.
Full textAbstract:
<p>Making the transition to ultra-long bridge design life requires a paradigm shift in the way bridge maintenance is considered. In order to achieve a very long service life, the maintenance program must be carefully planned and strictly executed throughout the structure’s life. A bridge’s bearings and expansion joints experience the full effects of traffic and the environment throughout that service life, and can act as ideal “smart” components</p><p>– incorporating integrated sensors in order to continuously monitor the components’ own performance, and the structure’s overall performance, over time. Installation and testing of such sensors in factory conditions allows very high quality control, which cannot easily be matched on site. So-called “wear elements”, such as the sliding surface materials in bearings and expansion joints, will need to be replaced a number of times during a long service life, even when using the highest-quality materials available. Recognizing this fact, and incorporating monitoring systems that can track the deterioration of such elements and provide advance warnings for the owner, can result in efficient life-cycle planning of bridge maintenance, vital for major transport infrastructure. Recent developments and added value of such “smart” technologies are discussed.</p>
Reports on the topic "Viral traffic"
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Chiavassa, Nathalie, and Raphael Dewez. Technical Note on Road Safety in Haiti. Inter-American Development Bank, January 2021. http://dx.doi.org/10.18235/0003250.
Full textAbstract:
The IDB has been a predominant partner supporting Haiti development efforts for many years. Nowadays, the IDB is the main source of investment for the country. Considering the vital weight of road transport sector in the socio-economy of the country, the IDB has concentrated a large part of investment efforts in rehabilitating and improving national road infrastructures. In the same time, a rapid increase of motorization and relatively higher speeds have contributed to increasing the number of traffic fatalities and injuries. In 2017, road injuries were the fifth cause of mortality in Haiti. The Road Safety situation of the country is preoccupying with many Vulnerable Road Users involved, in particular pedestrians and motorcyclists. The country is facing multi-sector challenges to address this Road Safety situation. Despite recent efforts, high political will has not been continuous in promoting a multi-sector coordination and the success of technical efforts remained mitigated over the last years. Road user awareness is still weak in the country. Risk factors include dangerous driving, bad safety conditions of vehicles, together with limited law enforcement and poor maintenance of safety devices on the roads. In this context, the Road Safety situation of the country may be getting worse in the coming years if no action is taken. However, the new Decade provides with a unique opportunity to achieve Sustainable Development Goals (SDGs) including significant progress in reducing the burden of traffic crashes. The IDB has already initiated vital investments in modernizing crash data collection, promoting institutional dialogue and supporting capacity building in the area of Road Safety. Future actions to address Road Safety challenges in Haiti in the framework of the five UN five pillars would require a range of investments in the area of political commitment, institutional coordination and technical efforts. A change of political paradigm from making roads for travelling faster to making roads safer for all users is highly needed at national level. This technical note on Road Safety in Haiti present the current situation of the country and provides with recommendations for future actions on Road Safety.