• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 122
  • 56
  • 27
  • 20
  • 16
  • 7
  • 7
  • 6
  • 5
  • 5
  • 4
  • 4
  • 2
  • 2
  • 2
  • Tagged with
  • 320
  • 86
  • 47
  • 44
  • 43
  • 38
  • 36
  • 31
  • 25
  • 22
  • 20
  • 20
  • 19
  • 19
  • 19
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

A study on service pricing and product differentiation in Hong Kong air cargo terminal service provision

Fong, Sui-man, Chapman. January 1994 (has links)
Thesis (M.A.)--University of Hong Kong, 1994. / Includes bibliographical references. Also available in print.
162

Steady state minimization of traveler cost for freeway corridor systems

January 1976 (has links)
by Michael B. McIllrath. / Bibliography: leaves 47-52. / Prepared under grant DOT/TSC 849. Originally presented as the author's thesis, (B.S.) in the M.I.T. Dept. of Electrical Engineering and Computer Science, 1976.
163

The genomic response to song and the representation of complex sounds in the auditory system of zebra finches / A resposta gen?mica ? can??o e a representa??o de sons complexos no sistema auditivo de tentilh?es zebra

Velho, Tarciso Andre Ferreira 06 1900 (has links)
Submitted by Helmut Patrocinio (hell.kenn@gmail.com) on 2017-11-19T18:33:02Z No. of bitstreams: 1 Tarcisio_Velho_TESE_2008.pdf: 3588366 bytes, checksum: 527ea32ab36807e796e40f24a77425a5 (MD5) / Approved for entry into archive by Ismael Pereira (ismael@neuro.ufrn.br) on 2017-11-22T12:06:30Z (GMT) No. of bitstreams: 1 Tarcisio_Velho_TESE_2008.pdf: 3588366 bytes, checksum: 527ea32ab36807e796e40f24a77425a5 (MD5) / Made available in DSpace on 2017-11-22T12:07:03Z (GMT). No. of bitstreams: 1 Tarcisio_Velho_TESE_2008.pdf: 3588366 bytes, checksum: 527ea32ab36807e796e40f24a77425a5 (MD5) Previous issue date: 2008-06 / The consolidation of long-lasting sensory memories requires the activation of gene expression programs. However, to fully understand the contribution of genomic events necessary for sensory learning, it is necessary to characterize the components involved in this response, their induction kinetics, and the possible functional interactions among individual components. Birdsong represents one of the best natural behaviors to study gene expression induced by auditory stimulation in awake, freely behaving animals. The present work addresses the properties and functional consequences of the genomic response to birdsong in zebra finches (Taeniopygia guttata), with a specific focus on the caudomedial nidopallium (NCM), a cortical-like auditory area involved in song auditory processing and memorization. We found that song induces a wellorchestrated cascade of gene expression that includes early and late genes. Early genes are co-expressed by NCM neurons and their induction is regulated by the mitogen-activated protein (MAP) kinase pathway. In addition, we also found that the induction of early genes is locally modulated by norepinephrine. We have also identified two late genes, syn2 and syn3, whose induction is repressed by early song-induced proteins genes in NCM. Functionally, we show that blockade of this response by ?-adrenergic antagonists disrupts the long-term maintenance of long-lasting neuronal changes triggered by song. Finally, we show that the pattern of early song-induce gene expression in NCM is stimulus dependent. These patterns also indicate the existence of functional subdomains of more or less selectivity towards conspecific songs. Overall, these results help us understand the functional significance of the genomic response to song and the functional organization of sound representation in a higher order auditory area of the songbird brain. / The consolidation of long-lasting sensory memories requires the activation of gene expression programs. However, to fully understand the contribution of genomic events necessary for sensory learning, it is necessary to characterize the components involved in this response, their induction kinetics, and the possible functional interactions among individual components. Birdsong represents one of the best natural behaviors to study gene expression induced by auditory stimulation in awake, freely behaving animals. The present work addresses the properties and functional consequences of the genomic response to birdsong in zebra finches (Taeniopygia guttata), with a specific focus on the caudomedial nidopallium (NCM), a cortical-like auditory area involved in song auditory processing and memorization. We found that song induces a wellorchestrated cascade of gene expression that includes early and late genes. Early genes are co-expressed by NCM neurons and their induction is regulated by the mitogen-activated protein (MAP) kinase pathway. In addition, we also found that the induction of early genes is locally modulated by norepinephrine. We have also identified two late genes, syn2 and syn3, whose induction is repressed by early song-induced proteins genes in NCM. Functionally, we show that blockade of this response by ?-adrenergic antagonists disrupts the long-term maintenance of long-lasting neuronal changes triggered by song. Finally, we show that the pattern of early song-induce gene expression in NCM is stimulus dependent. These patterns also indicate the existence of functional subdomains of more or less selectivity towards conspecific songs. Overall, these results help us understand the functional significance of the genomic response to song and the functional organization of sound representation in a higher order auditory area of the songbird brain.
164

Express?o do gene leptina, prote?mica e modelos para estima??o do CAR em animais da ra?a Nelore / Leptin gene expression, proteomics and models to estimate RFI in Nellore breed animals

Mota, L?cio Fl?vio Macedo 14 November 2014 (has links)
Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2016-01-12T17:40:07Z No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) lucio_flavio_macedo_mota.pdf: 1719975 bytes, checksum: 3893bff470fc397394ef7bd5048cfde3 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2016-01-12T17:40:32Z (GMT) No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) lucio_flavio_macedo_mota.pdf: 1719975 bytes, checksum: 3893bff470fc397394ef7bd5048cfde3 (MD5) / Made available in DSpace on 2016-01-12T17:40:32Z (GMT). No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) lucio_flavio_macedo_mota.pdf: 1719975 bytes, checksum: 3893bff470fc397394ef7bd5048cfde3 (MD5) Previous issue date: 2014 / Funda??o de Amparo ? Pesquisa do estado de S?o Paulo (FAPESP) / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Objetivou-se avaliar a influ?ncia da express?o da leptina e relacionar as concentra??es de leptina plasm?tica com as caracter?sticas de desenvolvimento corporal, mudan?as no proteoma do m?sculo Longissumus dorsi e o impacto o modelo na estima??o de equa??es de predi??o de consumo de alimentos em bovinos Nelore e no ranking de desempenho alimentar, utilizando diferentes modelos para a estimativa do consumo alimentar residual (CAR). Foi utilizado um total de 97 animais classificados para alto e baixo CAR, medidos para caracter?sticas de ingest?o, crescimento, efici?ncia alimentar, concentra??o plasm?tica de leptina e caracter?sticas de carca?a. Foram abatidos 20 animais classificados para alto e baixo CAR e coletadas amostras do m?sculo Longissimus dorsi, para an?lise da express?o do gene leptina e prote?mica. Os modelos utilizados para estima??o do CAR foram o modelo atualmente em uso e modelos que inclu?ram medidas de ultrassom de m?sculo e espessura de gordura. As amostras de prote?nas extra?das do m?sculo Longissimus dorsi foram separadas em duas etapas: a primeira etapa de separa??o das prote?nas foi realizada por migra??o eletrofor?tica em tira de IPG (Immobilized pH Gel) at? o ponto isoel?trico; a segunda, realizada pela migra??o eletrofor?tica das prote?nas focalizadas na tira de IPG (primeira dimens?o) e em seguida, em gel de acrilamida de acordo com o peso molecular (segunda dimens?o). Ap?s as an?lises dos g?is 2-D, os spots diferencialmente expressos nos grupos de CAR foram excisados para an?lise por dessor??o a laser, assistida por matriz MALDI TOF/TOF. As an?lises estat?sticas foram realizadas utilizando o procedimento MIXED do SAS, as estimativas de correla??o fenot?pica, utilizando o procedimento CORR e a compara??o dos valores de express?o entre as classes de CAR,utilizando o procedimentoCONTRAST do procedimento MIXED. Animais classificados para baixo CAR apresentaram maior express?o do gene leptina (2,80) e maior concentra??o plasm?tica (11,48) deste gene em bovinos Nelore. Os n?veis mais elevados de leptina podem estar envolvidos na redu??o da ingest?o de alimentos em animais classificados para baixo CAR, indicando ser um regulador na diferen?a de consumo de alimentos pelos animais. Embora os modelos de CAR tenham apresentado diferen?as na estima??o, as correla??es entre cada um dos modelos indicaram que estes n?o foram diferentes uns dos outros na classifica??o dos animais para efici?ncia alimentar. A maior express?o de fibras de contra??o lenta em bovinos mais eficientes ocorre devido a uma redu??o preferencial das fibras musculares de contra??o r?pida, como uma adapta??o para melhor lidar com a redu??o da exig?ncia nutricional, por apresentar diferen?as no perfil metab?lico da contra??o muscular. No entanto, a varia??o na efici?ncia do modelo que inclui os par?metros de composi??o corporal ? muito importante, sugerindo que a composi??o corporal pode ser fundamental para explicar a varia??o no consumo de alimentos e que ele precisa ser inclu?do no modelo de c?lculo do CAR. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2014. / ABSTRACT The objectives were to evaluate the effects of leptin expression and to correlate plasma leptin concentrations with corporal development traits, changes in proteomics of the Longissumus dorsi muscle, and the impact of the model approach in estimating predicting equations for feed intake in Nellore animals and in feed performance ranking using different models for the estimation of residual feed intake (RFI). A total of 97 animals, classified for high and low RFI, measured for intake, growth, feed efficiency, plasma leptin concentration, and carcass traits, was utilized. Twenty animals classified for high and low RFI were slaughtered, and Longissimus dorsi muscle was sampled to analyze leptin gene expression and proteomics. Models utilized for RFI estimation were the current model used, and models which included muscle ultrasound and fat thickness measurement. Protein samples of Longissimus dorsi muscle were separated into two stages: the first stage of proteins separation was performed by electrophoretic migration in IPG (Immobilized pH Gel) strip until the isoelectric point; the second, performed by electrophoretic migration of the proteins in the focused IPG strip (first dimension) and then, in acrylamide gel according to the molecular weight (second dimension). After analysis of 2-D gels, spots differentially expressed in RFI groups were excised for analysis by laser desorption assisted by MALDI TOF / TOF matrix. Statistical analyzes were achieved by using the MIXED procedure of SAS, estimation of phenotypic correlation, using the CORR procedure, and comparison of expression values ??among RFI classes, using the CONTRAST procedure of the MIXED procedure. Low RFI animals had greater expression of leptin gene (2.80) and greater plasma concentration (11.48) in Nellore animals. Greater levels of leptin can be involved in the reduction of feed intake in low RFI animals, indicating to be a regulator on feed intake. Although RFI models were different in estimating values, correlations among each model indicate that they were not different in classifying animals for feed efficiency. The greater expression of slow-twitch fibers in more efficient cattle is due to preferential reduction of the fast twitch muscle fibers, as an adaptation to better deal with reduced nutritional requirement because it shows differences in the metabolic profile of muscle contraction. Nonetheless, variation in efficiency of the model that includes body composition parameters is important, suggesting that body composition can be critical to explain variations in feed intake and it must be included in the RFI model.
165

Carga de trabalho e demandas produtivas no processo de encomenda expressa : um estudo de caso de uma empresa pública do setor de serviços

Ghisleni, Cristhian Luiz January 2012 (has links)
Em empresas responsáveis por serviços de encomenda expressa a concorrência é bastante acentuada. Neste caso, o planejamento e a adoção de estratégias eficazes de gerenciamento de recursos produtivos e humanos assume uma importância ainda maior. O objetivo geral deste trabalho foi o de estudar os problemas ergonômicos nas etapas e subetapas do processo produtivo em uma empresa pública de serviços de encomendas expressas e propor melhorias. Este documento contempla uma sequência de três artigos que abordam o tema produção e Ergonomia no processo produtivo de encomenda expressa. O primeiro artigo caracteriza a estrutura da empresa pública, objeto do estudo, e verifica como esta gerencia a Ergonomia. O referido artigo mostrou que algumas áreas, como a de encomendas expressas, carecem de estudos ergonômicos mais detalhados. Já o segundo artigo contextualiza o segmento de encomenda expressa brasileiro, as estratégias adotadas e as principais variáveis presentes na captação, tratamento e entrega. O estudo evidenciou que este mercado é muito acirrado com as empresas utilizando estratégias agressivas, como por exemplo, o atendimento 24 horas e a postagem de encomendas sem limite de peso para conquistar o cliente e que estas estratégias têm relação direta com o processo produtivo. No terceiro artigo, foi feito um comparativo entre as subetapas identificadas como gargalos produtivos do processo de encomenda expressa, incluindo a avaliação da carga de trabalho ou da penosidade em cada uma das subetapas gargalo. Isto permitiu estabelecer as prioridades das ações necessárias para a melhoria no contexto produtivo e ergonômico. / In companies responsible for express delivery, competition is highly pronounced. In this case, the planning and adoption of effective strategies for managing production and human resources take on even greater importance. The general goal of this work was to study ergonomic problems in the steps and substeps of the production process in a public express delivery company and to propose improvements. This paper looks at a set of three articles addressing the topic production and Ergonomics in the production process of express delivery. The first article describes the structure of the public company that is the object of study and verifies how it manages Ergonomics. The said article showed that some areas, such as express delivery, lack more detailed ergonomic studies. The second article puts the Brazilian sector of express delivery into context, the strategies adopted and the main variables present in the collection, treatment and delivery. The study indicated that this market is quite competitive, with companies using aggressive strategies, such as 24-hour service and shipping of parcels without weight limits, in order to win over customers. These strategies have straight relation with some aspects of production process. In the third article, a comparison was made between the substeps identified as production bottle necks in the express delivery process, including the evaluation of the workload or burden in each of the bottleneck substeps. This allowed for the establishment of priority actions needed to improve the productive and ergonomic setting.
166

Utveckling av en modern webbapplikation : En beskrivning av utvecklingsprocessen av en portfolioapplikation för omslags- och serietecknaren Anders Ferm

Wargentin, Anya January 2018 (has links)
Rapporten beskriver planering samt konstruktion av en ”modern webbapplikation” för serie- och omslagstecknaren Anders Ferm. Arbetet utfördes i syfte att erbjuda Anders en lättanvänd plattform för sin konst, där han själv kan publicera samt hantera media och information utan kunskap inom webbutveckling. Rapporten syftar till att ge inblick i hur några av de mer nya och populära webbutvecklingsramverken på marknaden kan arbetas med, samt besvara frågan om mindre traditionella ramverk och databaser faktiskt kan utföra de inom webben vanligaste typen av uppgifter och, om så är fallet, de faktiskt erbjuder fördelar över sina föregångare.
167

A Study of Franchising Models in Express Delivery Services in China

January 2018 (has links)
abstract: With regard to business modules in Chinese delivery services companies, there has long been a heated debate on whether franchising or direct management is the better module for Chinese market. But most prior discussion was lightweight, unconvincing and without any theoretical framework. This research examines three major management problems in Chinese delivery services: 1. The reason for choosing franchising module, 2. The relationship between franchising module and implementation of the product, 3. The functions of IT in delivery services. By reviewing theories on enterprise boundary and summarizing the six features of franchising contracts in Chinese delivery business as well as the five properties of delivery products, two contract models are finally set up with five beneficial conclusions which are proved by a very solid empirical data analysis. The purpose of this research is to either support or weaken the current theories on enterprise boundary as well as to offer meaningful inspirations for the management of express delivery companies in China. / Dissertation/Thesis / Doctoral Dissertation Business Administration 2018
168

Retrofit energ?tico em edif?cios de interesse hist?rico estudos de casos - edif?cios modernistas em Natal

Machado, Jos? J?lio Melo 09 June 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-12-15T18:42:26Z No. of bitstreams: 1 JoseJulioMeloMachado_DISSERT.pdf: 11499800 bytes, checksum: a947fe232a057bcab5e4e699591603a2 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2015-12-30T19:17:27Z (GMT) No. of bitstreams: 1 JoseJulioMeloMachado_DISSERT.pdf: 11499800 bytes, checksum: a947fe232a057bcab5e4e699591603a2 (MD5) / Made available in DSpace on 2015-12-30T19:17:27Z (GMT). No. of bitstreams: 1 JoseJulioMeloMachado_DISSERT.pdf: 11499800 bytes, checksum: a947fe232a057bcab5e4e699591603a2 (MD5) Previous issue date: 2014-06-09 / Este trabalho aborda a tem?tica do retrotif aplicado em edifica??es pertencentes ao quadro da produ??o arquitet?nica modernista com interesse hist?rico localizadas na ?rea urbana da cidade de Natal. O Objetivo geral ? identificar e compatibilizar procedimentos de retrofit e de preserva??o de patrim?nio arquitet?nico utilizando elementos de analise da express?o construtiva e par?metros da Rela??o Custo Beneficio (RCB), estabelecidas pela Ag?ncia Nacional de Energia El?trica - ANEEL. A hip?tese defendida ? a de que atrav?s do estimulo ao exerc?cio projetual de analise, em interven??es de retrofit, ? poss?vel se obter projetos com melhores resultados de RCB que contemplem os aspectos de preserva??o de patrim?nio arquitet?nico. Para tanto foram desenvolvidos fluxos de analise do processo e propostas solu??es de interven??o de elementos e sistemas que procuram melhorar o desempenho energ?tico da edifica??o, recuperando ou preservando os elementos arquitet?nicos. As propostas de interven??es passam por simula??es computacionais de desempenho atrav?s de sistemas como o DesignBuilder e Sun Tool. Os resultados energ?ticos foram convertidos no par?metro de analise do RCB e comparados com as express?o construtivas do projeto nas fases pr? e pois interven??o. A partir dos resultados, foi montado um gr?fico que tem como resultado um comparativo entre o RCB e a express?o construtiva das interven??es simuladas. / This paper addresses the theme of retrotif applied to buildings that belong to the modernist architectural production of historical interest located in the urban area of Natal . The overall objective is to identify and harmonize procedures for retrofit and architectural heritage preservation using elements of constructive analysis of expression and Benefit Cost Ratio ( BCR ) parameters established by the National Electric Energy Agency - ANEEL . The hypothesis put forward is that by stimulating the projetual year analysis , retrofit interventions , it is possible to obtain better results with projects RCB addressing the issues of preservation of architectural heritage . For both flow analysis of process solutions and proposals for action of elements and systems that seek to improve the energy performance of the building , restoring or preserving the architectural elements were developed . The proposed interventions undergo performance through computer simulations of systems such as DesignBuilder, Solar and Sun Tool. The energy results were converted to the analysis of RCB parameter and compared to the constructive expression of the project because the prenatal and intervention. From the results , a plot was constructed which results in a comparison between the RCB and the constructive expression of the simulated interventions
169

Estudo da influ?ncia dos genes LRP5, TGFB1, IGF1 e IGF1R no metabolismo ?sseo de pacientes com diabetes mellitus tipo 1

Souza, Karla Simone Costa de 31 July 2013 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-22T22:31:06Z No. of bitstreams: 1 KarlaSimoneCostaDeSouza_DISSERT.pdf: 1692324 bytes, checksum: 32db20c2cd32ce7a1804cd2222c5fe93 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-02-25T21:59:07Z (GMT) No. of bitstreams: 1 KarlaSimoneCostaDeSouza_DISSERT.pdf: 1692324 bytes, checksum: 32db20c2cd32ce7a1804cd2222c5fe93 (MD5) / Made available in DSpace on 2016-02-25T21:59:07Z (GMT). No. of bitstreams: 1 KarlaSimoneCostaDeSouza_DISSERT.pdf: 1692324 bytes, checksum: 32db20c2cd32ce7a1804cd2222c5fe93 (MD5) Previous issue date: 2013-07-31 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / A osteopatia ? uma complica??o cr?nica do diabetes tipo 1 (DM1). Alguns mecanismosv?m sendo propostos como principais fatores que desencadeiam altera??es no tecido ?sseo, dentreeles: a idade ao diagn?stico, tempo de doen?a, a presen?a de nefropatia e o controle glic?micoinsatisfat?rio. Neste sentido, o objetivo do presente estudo foi avaliar a express?o de RNAm dosgenes TGFB1, IGF1 e IGF1R e polimorfismos nos genes LRP5, TGFB1 e IGF1 de pacientes comDM1, e associ?-los com a presen?a de altera??es no metabolismo ?sseo. Foram estudados 100indiv?duos normoglic?micos (NG) e 101 pacientes com DM1, entre 6 e 20 anos. Os pacientesdiab?ticos foram analisados em sua totalidade (grupo DM1), e subdivididos em dois grupos, deacordo com o controle glic?mico: diab?ticos compensados (grupo DM1C) e diab?ticos n?ocompensados (grupo DM1NC). Avaliou-se o controle glic?mico (glicemia de jejum ehemoglobina glicada); a fun??o renal (ureia e creatinina s?ricas, e rela??o albumina/creatinina -RAC urin?ria); e o metabolismo ?sseo (c?lcio total e ionizado, f?sforo, atividade da fosfatasealcalina total - FAL e densidade mineral ?ssea - DMO) dos indiv?duos estudados. Tamb?m foideterminada a express?o do RNAm dos genes TGFB1, IGF1 e IGF1R e polimorfismos nos genesLRP5, TGFB1 e IGF1. A maioria dos indiv?duos com DM1 (65,3%) apresentou controleglic?mico insatisfat?rio (hemoglobina glicada >8%). Em rela??o ? fun??o renal, observou-se umaumento significativo nas concentra??es de ureia s?rica nos grupos DM1, DM1C e DM1NC e umaumento da RAC no grupo DM1NC em rela??o ao NG. No tocante aos marcadores bioqu?micosdo metabolismo ?sseo houve uma diminui??o das concentra??es s?ricas de c?lcio total nos gruposDM1, DM1C e DM1NC, e das concentra??es de c?lcio ionizado no grupo DM1 quandocomparados ao grupo NG. Tamb?m, houve um aumento significativo da atividade da FAL nogrupo DM1 em rela??o ao NG. A DMO estava significativamente diminu?da no grupo DM1quando comparado ao NG, sendo observada uma preval?ncia de 16,7% de indiv?duos diab?ticostipo 1 com baixa DMO. Na an?lise molecular, foram observadas diminui??es significativas naexpress?o dos genes TGFB1 e IGF1, e aumento significativo da express?o do gene IGF1R para ogrupo DM1 quando comparados ao NG. As frequ?ncias genot?picas e al?licas dos polimorfismosestudados foram significativas apenas para o polimorfismo do gene LRP5, demonstrando umaassocia??o deste polimorfismo com a susceptibilidade ao DM1. Por?m, n?o foram observadasassocia??es entre os polimorfismos e a osteopatia diab?tica. Estes resultados sugerem que ocontrole glic?mico insatisfat?rio, em conjunto com a presen?a de fatores de risco e altera??es emgenes envolvidos intimamente no metabolismo ?sseo, interfere na forma??o deste tecido,contribuindo para uma redu??o da DMO.
170

Prote?mica de Chromobacterium violaceum submetida ? microgravidade simulada

Santos, Jonathas Diego Lima 15 December 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-03-21T11:48:14Z No. of bitstreams: 1 JonathasDiegoLimaSantos_TESE.pdf: 8935214 bytes, checksum: 86433d89608ea11b99ac2a3911f14149 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-03-23T11:23:51Z (GMT) No. of bitstreams: 1 JonathasDiegoLimaSantos_TESE.pdf: 8935214 bytes, checksum: 86433d89608ea11b99ac2a3911f14149 (MD5) / Made available in DSpace on 2018-03-23T11:23:51Z (GMT). No. of bitstreams: 1 JonathasDiegoLimaSantos_TESE.pdf: 8935214 bytes, checksum: 86433d89608ea11b99ac2a3911f14149 (MD5) Previous issue date: 2017-12-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Chromobcterium violaceum (C. violaceum) ? uma bact?ria Gram-negativa, encontrada em regi?es tropicais e subtropicais, considerada organismo modelo de vida livre. Alguns estudos prote?micos realizados com esta bact?ria demonstraram sua capacidade de adapta??o a desafios ambientais, como alta concentra??o de ferro e exposi??o ao estresse oxidativo. No entanto, nenhum estudo foi feito com esta esp?cie submetida ? microgravidade simulada (MGS), ou seja, em condi??es em que a gravidade ? artificialmente reduzida para menos de 1xg. Estudos MGS podem ser importantes para entender as modula??es em n?vel molecular sofridas pelos organismos vivos. Portanto, o objetivo deste estudo foi caracterizar a resposta de C. violaceum, como organismo modelo de vida livre, cultivado em MGS, usando t?cnicas de prote?mica para entender como a bact?ria responde a esse estresse. A MGS foi conseguida por meio da rota??o do vessel ao redor do eixo horizontal perpendicular ao vetor gravitacional nos sistemas de cultura de c?lulas rotativas - Rotating Cell Culture Systems ? (RCCS4). MGS foi conduzido a uma velocidade de 40 rpm por um per?odo de 12 horas para obter a curva de crescimento a cada 2 horas. Prote?nas totais foram extra?das de amostras de cultura de c?lulas bacteriana coletada ?s 5 e 12 horas, correspondendo as fases exponenciais inicial (MG5) e tardia (MG12), respectivamente, tendo a curva de crescimento como refer?ncia. Ap?s a tripsiniza??o, as amostras foram analisadas em espectr?metro de massas Q-TOF. Como resultado um total de 212 prote?nas durante ?s 5h de crescimento e 192 ?s 12h foram detectadas, das quais 144 delas foram comuns em ambos os per?odos. No proteoma de C. violaceum obitido em 5h de crescimento 195 prote?nas foram identificadas em gravidade normal (GN5) e 155 prote?nas foram identificadas em MG5, sendo 18 upreguladas, 19 downreguladas e 17 expressas somente na condi??o de MG5. No proteoma obtido em 12h de crescimento, 165 prote?nas foram identificadas em gravidade normal (GN12) e 173 em MG12, das quais, 17 foram upreguladas, 22 downreguladas e 28 expressas somente na condi??o de MG12 Al?m disso, foi poss?vel identificar 25 prote?nas com fun??o desconhecida em MG5 e MG12. Utilizando ferramentas computacionais foi poss?vel construir redes de intera??es prote?na-prote?na (PPI) e as sub-redes contendo grupo de prote?nas com fun??es correlacionadas, analisar vias metab?licas, processos biol?gicos, contexto gen?mico e busca por dom?nios conservados e sequ?ncias hom?logas de prote?nas com fun??o desconhecida. Como resultado, identificamos sub-redes relacionadas com a bioss?ntese de prote?nas, regula??o da transcri??o e tradu??o, resposta ao estresse e metabolismo energ?tico, conclu?mos que as respostas celulares associadas ? express?o diferencial induzida pela MGS levaram ? diminui??o do crescimento de C. violaceum, acompanhado pela regula??o negativa de prote?nas relacionadas com processos transcricionais, traducionais e libera??o de energia por vias aer?bicas e pela regula??o positiva de prote?nas envolvidas no estresse oxidativo, na via anaer?bica e na sobreviv?ncia celular. / Chromobcterium violaceum (C.violaceum) is a Gram-negative bacteria, which has been found at tropical and subtropical regions, considered a free living model organism. Some proteomic studies performed with this bacterium have demonstrated its ability to adapt to environmental challenges such as high iron concentration and oxidative stress exposure. However, no study was made with this specie submitted to simulated microgravity (SMG), that is, under conditions in which the gravity is artificially reduced to less than 1xg. MGS studies may be important in understanding the molecular-level modulations undergone by living organisms. Therefore, the aim of this study was to characterize the response of C. violaceum, as free-living model organism, cultured at MGS, using proteomics techniques in order to understand how this bacterium response to this stress. The SMG was achieved by rotating the vessel around the horizontal axis perpendicular to the gravitational vector in Rotating Cell Culture Systems (RCCS4). SMG was conducted at a speed of 40 rpm for a period of 12 hours to obtain the growth curve every 2 hours. Total protein extraction was made in two times: 5 and 12 hours, corresponding to early (MG5) and late (MG12) exponential phase, respectively, taking the growth curve as a reference. After trypsinization, samples were analyzed with Q-TOF mass spectrometer. As a result a total of 212 proteins during 5h of growth and 192 at 12h were detected, of which 144 of them were common in both periods. We detected 155 proteins during MG5, from which 18 proteins were upregulated, 19 down-regulated and 17 proteins were exclusive when compared to GN5. In the proteome obtained in 12h of growth, 165 proteins were identified in normal gravity (GN12) and 173 in MG12, of which, 17 were upregulated, 22 were downregulated and 28 expressed only in MG12 condition. In addition, it was possible to identify 25 proteins with unknown function in MG5 and MG12. Using computational tools it was possible to construct networks of protein-protein interactions (PPI) and sub-networks containing group of proteins with correlated functions, to analyze metabolic pathways, biological processes, genomic context and search for conserved domains and homologous sequences of proteins with unknown function . As a result, we identified sub-networks related to protein biosynthesis, transcription regulation and translation, stress response and energetic metabolism, we conclude that the cellular responses associated with differential expression induced by MGS led to a decrease in the growth of C. violaceum, accompanied by the negative regulation of proteins related to transcriptional, translational and energy release by aerobic pathways and by the positive regulation of proteins involved in oxidative stress, anaerobic pathway and cell survival.

Page generated in 0.0276 seconds