Дисертації з теми "Ppev"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Ppev.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "Ppev".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Gouin, Carla. "Tropisme cellulaire initial du SARS-CoV-2 dans le poumon humain : du poumon entier aux sous-populations de macrophages." Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASL147.
Анотація:
Les mécanismes pathogéniques impliqués dans les phases initiales de l'infection par le SARS-CoV-2 restent mal compris au niveau pulmonaire, en dépit d'une abondante activité de recherche depuis l'émergence de la pandémie COVID-19. Des travaux conduits sur des modèles de culture de cellules humaines isolées, d'explants, d'organoïdes ou de lung-on-a-chip ont donné des résultats discordants quant aux cibles initiales pulmonaires principales du virus et à la réponse innée induite. Dans ce travail de thèse, j'ai évalué un modèle original d'étude des premières étapes de l'infection virale qui consiste à infecter un poumon humain entier maintenu vivant ex vivo selon une technique utilisée couramment en transplantation pulmonaire, permettant ainsi d'étudier l'infection dans des conditions respectant les interactions spatiales. Cette technique (perfusion pulmonaire ex vivo, PPEV) consiste à ventiler et perfuser des poumons pendant quelques heures et conduit à évaluer et réhabiliter des poumons dits marginaux. Par la technique de RNA-seq sur cellule unique, nous avons découvert que le poumon entier maintenu sous PPEV sans virus présente un programme d'activation génique particulier que nous avons exploré dans un premier volet de la thèse. Ainsi nous avons mis en évidence, que la PPEV en elle-même induit une réponse inflammatoire qui varie en fonction du temps et des types cellulaires. Cette réponse s'accompagne d'une signature génique indiquant une réduction de la signalisation du cytosquelette dans les cellules épithéliales alvéolaires de type 2 et les cellules endothéliales, ainsi qu'une réduction de la migration et de l'activation des lymphocytes et cellules dendritiques. Ce travail révèle pour la première fois la réponse biologique à la PPEV en fonction des types cellulaires, potentiellement associée à des effets sur les suites cliniques. Dans un second temps, nous avons infecté sous PPEV des poumons avec différents isolats viraux et réalisé des analyses de RNA-seq sur cellule unique qui ont révélé que les macrophages alvéolaires (AMs) et ceux dérivés des monocytes (MoMacs) sont les cibles principales du virus. Par contre, les cellules épithéliales et les sous-populations de monocytes pulmonaires ne sont pas significativement associées au virus. Nous avons étudié la réponse de différents types de monocytes/macrophages in vitro après dissociation de tissus pulmonaire humain, tri en cytométrie puis culture avec le virus. Nous avons révélé des réponses spécifiques inflammatoires en fonction des populations cellulaires, des souches virales et des doses, les cellules MoMacs étant les plus inflammatoires en réponse au virus. Ces résultats originaux mettent en évidence le rôle des macrophages à l'étape initiale de l'infection et suggèrent que leur réponse pourrait conditionner l'apparition des lésions ultérieures associées à la gravité en fonction de la composition initiale alvéolaire en sous populations de monocytes/macrophages, de la souche virale et de la dose. Dans un projet parallèle, j'ai étudié une méthode visant à réduire cette inflammation, sur poumon de porc, en procédant à une dialyse du perfusat pour éliminer les déchets métaboliques accumulés. Nous avons montré que la dialyse ne réduit pas l'inflammation, mais l'augmente plutôt, après 6 ou 12 heures.Au total, ce projet de thèse a montré les atouts et les limites d'un modèle d'infection virale de poumon entier maintenu ex vivo. Il a mis en lumière l'implication des sous-populations de monocytes/macrophages dans les premières étapes de l'infection par le SARS-CoV-2. Il a également conduit à mieux comprendre les mécanismes cellulaires et moléculaires impliqués dans la technique de maintien ex vivo du poumon, ce qui sera utile pour améliorer la conduite de la transplantationThe pathogenic mechanisms of the initial phase of the SARS-CoV-2 infection remain poorly understood at the pulmonary level, despite strong research efforts since the emergence of the COVID-19 pandemics. Studies conducted with various models, including isolated human cell cultures, explants, organoids or lung-on-a-chip systems have generated conflicting results concerning the primary pulmonary targets of the virus and the induced innate immune responses.In my thesis, I evaluated an original model for studying the early stages of viral infection. This model involves the infection of a whole lung that is maintained ex vivo with a technique used in lung transplantation, allowing the study of infection under conditions that preserve spatial interactions. This technique (ex-vivo lung perfusion, EVLP) involves ventilating and perfusing lungs for several hours and has the potential to evaluate and rehabilitate marginal lungs. We conducted single-cell RNA-seq analyses and we discovered that the whole lung maintained under EVLP without the virus displayed a specific gene activation program, which we analyzed in the first part of my thesis. We found that EVLP in itself induced an inflammatory response that varied over time and across cell types. This response was accompanied by gene signatures indicating reduced signaling of cytoskeleton in alveolar type 2 epithelial cells and endothelial cells, as well as reduced cell migration and activation of lymphocytes and dendritic cells. This work reveals, for the first time, the biological responses to EVLP based on cell types that may be related to the clinical outcomes. In the second part of my thesis, we infected lungs under EVLP with different viral isolates and conducted single-cell RNA-seq analyses. These analyses revealed that alveolar macrophages (AMs) and monocyte-derived macrophages (MoMacs) are the primary targets of the virus. Epithelial cells and pulmonary monocyte subpopulations were not significantly associated with the virus. We studied the response of the monocyte/macrophage populations in vitro after dissociation of human lung tissue, flow cytometry sorting and culture with the virus. We observed specific inflammatory responses depending on cell subsets, viral strain and doses, with MoMacs being the most inflammatory. Our original work reveals the role of monocyte/macrophage subsets in the initial phases of the SARS-CoV-2 infection and suggests that the initial response of alveolar monocyte/macrophages will drive the subsequent development of lung injuries, depending on the composition in AMs and MoMacs, the viral strain and doses. In a parallel project, we investigated the effects of a method aimed at reducing the inflammation during EVLP, on porcine lung, by performing a dialysis of the perfusate to remove accumulated metabolic wastes. However, our findings showed that dialysis did not reduce inflammation; rather, it increased inflammation after 6 or 12 hours.Overall, this thesis project has demonstrated the strengths and limitations of a whole lung viral infection model maintained ex-vivo. It has highlighted the involvement of monocyte/macrophage subpopulations in the initial step of SARS-CoV-2 infection and has also contributed to a better understanding of the cellular and molecular mechanisms involved in the ex vivo lung maintenance technique, which will be useful for improving lung transplantation procedures
2
Jonasson, Simon. "Phoenix. : PPE wildfire respirator." Thesis, Umeå universitet, Designhögskolan vid Umeå universitet, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-162081.
Анотація:
Forest fires has become an increasing threat all over the world. Pollution and rising greenhouse gases has led to an ever increase in global temperatures. Sweden has previously been spared from larger fires, but in the past few year it has been been made clear that these climate changes will affect the number and intensity of forest fires. In this project I have investigated how forest fires work and how the process of extinguishing them looks today. With a focus on the personal equipment I have looked into how to improve the working environment and the safety for fire-fighters. Using the design process this problem is tackled from a holistic point of view, looking at both the users and context. The solutions presented in this project is a professional safety product called “Phoenix. PPe Wildfire respirator”. A lightweight portable oxygen harness with an attached emergency mask.
3
Souza, Solange Maria Batista de. "Contribuições à implementação do PPEC: superando dualidades." Universidade Federal de Juiz de Fora, 2015. https://repositorio.ufjf.br/jspui/handle/ufjf/1375.
Анотація:
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-03T19:51:31Z
No. of bitstreams: 1
solangemariabatistadesouza.pdf: 3126349 bytes, checksum: 525938cce27840ef652c0c257a0bc89a (MD5)Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-06-07T15:20:13Z (GMT) No. of bitstreams: 1 solangemariabatistadesouza.pdf: 3126349 bytes, checksum: 525938cce27840ef652c0c257a0bc89a (MD5)
Made available in DSpace on 2016-06-07T15:20:13Z (GMT). No. of bitstreams: 1 solangemariabatistadesouza.pdf: 3126349 bytes, checksum: 525938cce27840ef652c0c257a0bc89a (MD5) Previous issue date: 2015-07-16
O presente trabalho, intitulado “Contribuições à implementação do PPEC: superando dualidades”, foi desenvolvido no Mestrado Profissional em Gestão e Avaliação da Educação Pública da Universidade Federal de Juiz de Fora, com o objetivo de apresentar propostas para o aprimoramento da implementação do PPEC (Projeto de Pesquisa de Enriquecimento Curricular), em uma Escola Técnica Estadual no Estado do Espírito Santo, tendo em vista a importância e a necessidade de avaliação dessa política pública, contribuindo para o seu aprimoramento. Os sujeitos envolvidos foram os professores e alunos do CEET Vasco Coutinho, que participaram desta pesquisa por meio de entrevista semiestruturada para os professores e questionários para os alunos. A realização deste estudo foi estruturada em duas categorias centrais: trabalho como princípio educativo, fundamentado nos autores, Gaudêncio Frigotto, Maria Ciavatta, Marise Ramos, Acácia Kuenzer, Ramon Oliveira, Dermeval Saviani e Ronaldo Araújo e a pesquisa como princípio educativo, baseada nas concepções de Marise Ramos, Pedro Demo, nas Diretrizes Curriculares de EPT e nas Leis Federais e Estaduais. Ao final, foi apresentado um Plano de Ação Educacional, a partir dos resultados obtidos na pesquisa, no que se refere às fragilidades e aos pontos positivos. Esse plano foi organizado com base em três categorias centrais: Interdisciplinaridade, Sustentabilidade e Inovação, tendo como foco a revitalização do currículo de EPT e o aprimoramento e monitoramento dessa política pública.
This work, entitled "Contributions to the Implementation of the PPEC: Overcoming Dualities", was developed in the Professional Masters in Management and Public Education Evaluation of the Federal University of Juiz de Fora, in order to submit proposals for improving the implementation of the PPEC ( Research Project Enrichment Curriculum) in a public technical school in Espírito Santo state, in view of the importance and the need for evaluation of this public policy in order to contribute to its improvement. The subjects involved were teachers and students of CEET Vasco Coutinho, who took part in this research through semi-structured interviews for teachers and questionnaires for students. This research was structured into two main categories: work as an educational principle based on the authors, Gaudêncio Frigotto, Maria Ciavatta, Marise Ramos, Acacia Kuenzer, Ramon Oliveira, Dermeval Saviani and Ronaldo Araújo and research as an educational principle, based on the concepts of Marise Ramos, Pedro Demo, the Curriculum Guidelines of EFA and the Federal and State Laws. At the end, it was presented an Educational Action Plan from the results obtained in the research regarding to the weaknesses and the strengths of the project. The plan was organized from three main categories: Interdisciplinary, Sustainability and Innovation, focusing on the revitalization of the EPT (Professional and Technical Education) curriculum and the improvement as well as the monitoring of this public policy.
4
Kub, Christopher. "Hyperbranched conjugated polymers: an investigation into the synthesis, properties and postfunctionalization of hyperbranched poly(phenylene vinylene-phenylene ethynylene)s." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34838.
Анотація:
There are two general ways to introduce functionalities into a polymeric structure: functionalization of the monomeric units before polymerization and postfunctionalization of the preformed polymer. Building libraries of polymers with different functionalities can be completed with significantly less effort by the second method, as each postfunctionalization of a single batch of polymeric backbone can involve as little as one synthetic step.
One method of building a polymeric backbone for postfunctionalization involves the synthesis of hyperbranched conjugated polymers (HCPs) from AB2 monomeric units. A polymer formed from n AB2 monomeric units should contain n reactive B groups, which act as sites of functionalization. Utilizing this principle, two different hyperbranched poly(phenylene vinylene-phenylene ethynylene) scaffolds were synthesized and studied in both their inherent properties and functionalization.
The first HCP synthesized was compared against a monomeric cruciform model and a linear polymer with a similar structure. The hyperbranched polymer has red-shifted absorption and emission in comparison to the cruciform model and linear polymer. The HCP quenches paraquat more efficiently than the linear polymer by a factor of about two, suggesting a greater rate of energy transfer.
The functionalization of HCPs was studied; iodine groups decorating the HCPs were replaced with terminal alkynes by Pd-catalyzed coupling, providing a library of 24 differently functionalized HCPs. Elemental analyses of the postfunctionalized polymers show nearly complete substitution of the iodine groups. The postfunctionalized polymers show increased fluorescence compared to the original iodine decorated polymers, due to the loss of the heavy atom effect inducing iodine groups. The emissions of the postfunctionalized polymers in solution show a strong dependence on the groups attached to the conjugated structures, with emission maxima ranging from 505 nm to 602 nm; quantum yields range from 0.7% to 25%. Solid-state emission studies show stronger and more red-shifted spectra compared to emissions observed in solution.
5
Fischer, Timo. "Parapockenvirus (PPV) als neuartige Vektorvakzine Entwicklung Pseudorabiesvirus-(PRV)-spezifischer PPV-Rekombinanten und Untersuchung deren Immunogenität im Mausmodell /." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965634124.
6
Gamael, Amin. "Ergebnisse nach kombinierter Operation PPV und Linsenchirurgie /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972337334.
7
Silva, Ricardo Manuel Pinho. "Células solares orgânicas baseadas em MEH-PPV." Master's thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/2626.
Анотація:
Mestrado em Engenharia FísicaNo presente trabalho procedeu-se ao estudo e fabrico de células solares orgânicas do tipo bulk heterojunction, baseadas no polímero poly(2-methoxy-5- (2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) dopada com a nanoestrutura [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) em filmes finos . A caracterização opto-electrónica revelou uma forte absorção na zona espectral azul-verde, confirmando a aplicabilidade destes materiais para este tipo de dispositivos. Foram obtidos valores relevantes em parâmetros como factor de forma e eficiência. É apresentada uma tentativa de explicação dos resultados com base nas propriedades micro-eléctricas e morfológicas. Produziram-se, de igual forma, células flexíveis baseadas na mesma estrutura, tendo em vista a sua aplicabilidade em larga escala. ABSTRACT: In this work some thin film bulk-heterojunction organic solar cells based on polymer poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEHPPV) doped with nanostructures [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was made and studied. The opto-electrical characterization showed a strong absorption in the blue-green spectrum region, confirming the applicability of these materials for this kind of devices. Relevant data was obtained for fill-factors and efficiency. An attempt to explain the macroscopic behavior based on micro-electrical and morphological properties was done. Flexible devices based on same structure were also made in order to test the possible application in large scale.
8
Greenham, Neil Clement. "Electroluminescence in conjugated polymers." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296643.
9
Bailey, Dalan. "Development of reverse genetics for peste des petets ruminants virus (PPRV)." Thesis, University of Reading, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494788.
Анотація:
Peste des petits ruminants virus (PPRV), a member of the Morbillivims genus in the family Paramyxoviridae, is the cause of a serious and emerging plague of small ruminants, mostly affecting sheep and goats. It is endemic in many developing countries in Africa and southern Asia and is highly contagious, with the mortality rate approaching 90% in some outbreaks. Development of reverse genetics systems for other morbilliviruses such as rinderpest and measles has allowed more focused research into replication, pathogenicity and marker vaccines.
10
Cossiello, Rafael Di Falco 1980. "Fotofisica de polimeros emissores de luz : MEH-PPV." [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249455.
Анотація:
Orientador: Teresa Dib Zambon AtvarsDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
Made available in DSpace on 2018-08-03T21:54:50Z (GMT). No. of bitstreams: 1 Cossiello_RafaelDiFalco_M.pdf: 1572837 bytes, checksum: 19e63ede7b38e238cbb9b8b3d9a68b93 (MD5) Previous issue date: 2003
Mestrado
11
Wallaart, Johannes Christiaan Safety Science Faculty of Science UNSW. "Identification, elimination and reduction of barriers to the effective use of respiratory personal protective equipment." Publisher:University of New South Wales. Safety Science, 2008. http://handle.unsw.edu.au/1959.4/43293.
Анотація:
This thesis is concerned with the identification, elimination and reduction of barriers to the use of personal respiratory protective equipment (RPE) in the workplace to reduce and prevent occupational inhalation disease. Respiratory Protective Equipment (RPE) is widely used in industry, health, emergency response, military settings and many other applications and are in daily use by thousands of people in Australasia. The equipment is generally used to filter or ab/adsorb the contaminants from the air prior to delivery to the wearer by filtering or ad/absorbing contaminants from the air prior to being breathed. There is increasing concerns being expressed worldwide as well as in Australia and New Zealand about the apparent increase in diagnosed occupational diseases and the use of RPE is an essential preventative measure able to be adopted by workplaces. The use of this type of equipment is the option after the preferred options of elimination and isolation of the individual from the contaminant in the atmosphere. In spite of this, many different types of RPE are routinely in use. There are, however, enormous practical, physiological and psychological difficulties in the wearing of RPE. Concerns have been expressed in the literature as well as in practical situations that many different types of RPE was unable to meet the needs of workers, particularly as related to airflows and that current standards did not reflect the real-life workplace demands. This work set out to determine an improved methodology for users to determine the total inward leakage (TIL), the different types and quantities of airflows, particularly Peak Inspiratory Air Flows (PIAF). When communicating (an essential aspect in the workplace for safety reasons), PIAFs rise dramatically. This work showed that PIAF were very high, particularly when communicating, and is likely to exceed the ability of many commercial types of commercially available respiratory equipment as well being in excess of the certification requirements of standard bodies. In addition, Minute Volumes (MV) in a typical Australian workforce were shown to be very variable between individuals and current certification requirement of airflows do not appear to reflect practical use. The thesis further investigated using a questionnaire survey, the knowledge and current intervention measures adopted by farmers in different sections of agriculture, particularly dairy farming. Agriculture in New Zealand is a critical economic activity, employing 10% of the total workforce. This work showed that in spite of many different types of intervention activity spread over many years by Government agencies and private organisations to date, limited awareness exists of inhalation diseases and appropriate types of RPE in different applications (for example, confined space applications). The research would suggest that a different and more intensive approach is needed by Government agencies to address the problem in this workplace community if workplace inhalation diseases are to be reduced in the future.
12
Lear, Jeremy M. "The Synthesis of Benzyloxy Substituted DP-PPV and Examination of the Horner-Wadsworth-Emmons Reaction in the Synthesis of DP-PPV." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401459783.
13
Janakiraman, Umamaheswari. "Analysis of electrogenerated chemiluminescence of PPV type conducting polymers." Doctoral thesis, [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968755305.
14
Weir, Bruce Alexander. "Structure and morphology of PPV-derived polymers and oligomers." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621077.
15
Grimes, Amy Frances. "Toward optimization of photomodulation of azobenzene-modified PPV derivatives." College Park, Md. : University of Maryland, 2007. http://hdl.handle.net/1903/7607.
Анотація:
Thesis (Ph. D.)--University of Maryland, College Park, 2007.Thesis research directed by: Dept. of Chemistry and Biochemistry. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
16
Saar, Brooklynd Dawn. "Fluorescence Quenching of PPV-SO and Bodipy-Naphthalene Systems." W&M ScholarWorks, 2012. https://scholarworks.wm.edu/etd/1539626932.
17
Masuda, Koji. "Design and Fabrication of Nanostructures by Layer-by-Layer Assembly for Organic Photovoltaic Devices." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/123342.
18
Thamyongkit, Patchanita. "Synthesis and characterization of pyrazine and phthalocyaninatonickel(II) substituted PPV analogous oligomers Synthese und Charakterisierung von Pyrazin- und Phthalocyaninatonickel(II)-substituierten PPV-anologen Oligomeren /." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963899929.
19
Wetzel, Thierry. "Obtention d'outils moléculaires pour la détection et la différenciation du virus de la sharka (PPV) : clonage de l'ARN génomique d'une nouvelle souche de PPV." Bordeaux 2, 1991. http://www.theses.fr/1991BOR22016.
Анотація:
Le plum pox potyvirus (ppv) est l'agent responsable de la sharka, la maladie virale actuellement la plus grave pour les arbres fruitiers a noyau. A cause de la faible concentration et de la repartition irreguliere du virus dans les arbres infectes, des techniques de detection du virus extremement sensibles sont necessaires. Un test de detection du ppv par hybridation moleculaire utilisant des sondes arnc marquees au #3#2p correspondant a des genes codant pour des proteines virales non structurales de ppv-d ont permis une augmentation de la polyvalence du test par rapport a une sonde correspondant au gene de la proteine de capside. Ces sondes ont detecte avec une sensibilite maximale un grand nombre d'isolats de ppv a l'exception d'un isolat egyptien: ppv-e1 amar. L'arn genomique de ppv-e1 amar a ete clone et sa moitie 3 a ete sequencee. Des niveaux de divergence de 20% ont ete observes au niveau des acides nucleiques, 10% au niveau des acides amines, par rapport aux sequences correpondantes de 3 autres souches de ppv, homologues a 98% entre elles. Ppv-e1 amar se presente donc comme une souche atypique de ppv. Un protocole de detection du ppv par pcr, dans un seul tube s'est avere polyvalent et a demontre une plus grande sensibilite par rapport a l'hybridation moleculaire utilisant des sondes arnc radiomarquees. Un protocole modifie de pcr par l'introduction d'une etape prealable d'immunocapture du virus (ic/pcr), a permis d'augmenter la sensibilite de 100 fois, 250 fois et 2000 fois par rapport a la pcr, l'hybridation moleculaire et le test elisa respectivement
20
Timpanaro, Salvatore. "Conductive properties and morphology of conjugated molecular materials studied by local probe techniques." Phd thesis, [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974115991.
21
Mahasha, Phetole Walter. "The trafficking of the Mycobacterium tuberculosis PE and PPE proteins." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/1862.
Анотація:
Thesis (MScMed (Biomedical Sciences. Molecular Biology and Human Genetics))--University of Stellenbosch, 2007.The expansion of the Mycobacterium tuberculosis PE and PPE gene families seems to be linked to that of the immunologically-important ESAT-6 (esx) gene clusters secretion system, as the ancestral members of these families are found only within the ESAT-6 gene cluster regions. These ancestral members are also the only copies in the earlier mycobacteria like M. smegmatis. The later duplications of the PE and PPE families belonging to the PGRS and MPTR subgroups, have been implicated in virulence and are only found within the genomes of the pathogenic mycobacteria closely related to the M. tuberculosis complex. The aim of this study was to compare the subcellular localization of the later duplications of the PE and PPE gene families belonging to the PGRS and MPTR subgroups with that of the ancestral PE and PPE proteins found in M. smegmatis and to investigate whether the ESX secretion apparatus is involved in the trafficking of these proteins. The PE (Rv3872) and PPE (Rv3873) genes from M. smegmatis were PCR amplified with a C-terminal HA tag using M. smegmatis genomic DNA as template. Two PPE-MPTR genes, Rv0442c and Rv0878c, and one PE_PGRS gene, Rv2615c, were also PCR amplified with a C-terminal HA tag using M. tuberculosis genomic DNA as template. All genes were cloned into the mycobacterial expression vector p19Kpro. Expression and localization was investigated using SDS-PAGE and Western blotting. The PE and PPE genes expressed in M. smegmatis were found to be present within the cell wall, membrane, and cytosol fractions, but not in the culture filtrate, indicating no secretion. The PPE-MPTR and PE_PGRS genes expressed in M. smegmatis, were also found to be present within the cell wall, membrane and cytosol fractions, but not in the culture filtrate, indicating that they are also not secreted. We hypothesize that their secretion is dependent on ESAT-6 gene cluster region 5, which is absent from the genome of M. smegmatis. Ancestral PE and PPE proteins are secreted efficiently in M. tuberculosis. The ESAT-6 gene cluster Region 3 and Region 4 of M. smegmatis were knocked out, and these knockout mutants could be used in future studies to investigate if the ESAT-6 gene cluster region 1 is involved in the secretion of the ancestral and recent PE and PPE proteins.
22
Fogle, Jeffrey D. "Synthesis of Fluorinated Indenofluorenediones and Bis(2-fluorophenyl) Substituted PPV." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1309441933.
23
Costa, Rui Jorge Gonçalves. "Interpretação no turismo: o caso do Portugal dos Pequenitos (PPE)." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/9338.
Анотація:
Mestrado em Gestão e Planeamento em TurismoAtualmente, o Turismo tem-se afirmado como uma das principais atividades económicas a nível mundial. Em Portugal, o Turismo representa cerca de 10% do PIB nacional, sendo vital para o desenvolvimento e crescimento de toda a economia nacional. Com o aparecimento de novas necessidades dos turistas, a interpretação assume-se como uma das principais ferramentas do Turismo, dando resposta às diferentes exigências e motivações dos turistas e tem promovido a identidade cultural das atrações turísticas e uma maior satisfação dos turistas. Assim, pretendeu-se com este projeto: (i) Compreender o que é a interpretação no Turismo; (ii) Analisar o potencial impacte da interpretação para os turistas e para os destinos; (iii) Compreender todo o planeamento de um processo de interpretação, incluindo o processo de avaliação da interpretação; (iv) Avaliar a interpretação no “Portugal dos Pequenitos (PPE)”. No sentido de cumprir os objetivos propostos foi realizada uma entrevista dirigida aos visitantes do PPE, tendo-se obtido vinte entrevistas, divididas por quatro grupos diferentes de visitantes. Feita a análise dos dados recolhidos e entre várias conclusões encontradas, a mais importante que se pode retirar da investigação empírica é que, de facto, um plano de interpretação eficiente pode potenciar a competitividade e o valor cultural/histórico das atrações turísticas.
Nowadays, tourism is one of the main economic activities worldwide. In Portugal, tourism it represents about 10% of national GDP, being vital for the development and growth of the entire national economy. With the emergence of new needs of tourists, the interpretation became one of the main tools of tourism, giving answer to the various requirements and motivations of tourists and has promoted the cultural identity of tourism attractions and a greater satisfaction of tourists. Thus, with this project it was aimed to: (i) Understand what the interpretation in tourism is; (ii) Analyze the potential impact of interpretation for tourists and destinations; (iii) Understand the planning of an interpretation process, including the assessment of interpretation; (iv) Evaluate the interpretation in the "Portugal dos Pequenitos (PPE)." In order to achieve the proposed objectives was held an interview aimed at visitors of PPE was held and twenty interviews were obtained, divided by four different groups of visitors. After doing the analysis of the data collected, among several conclusions found, the more important that can be withdraw from the empirical research is, indeed, that a powerful interpretation plan can boost competitiveness and cultural/historical value of tourist attractions.
24
Majeed, Awais. "A process performance evaluation framework (PPEF) for partner selection during virtual organisation creation phase." Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504699.
Анотація:
A Virtual Organisation (Va) is a form of collaborative network that is formed when multiple independent enterprises join together to share theirs skills, costs, resources and knowledge, in order to respond to a new business opportunity. Normally,' such enterprises use information and communication technologies (lCT) for collaboration and cooperation. Selection of partner enterprises to form the va is the most important activity in the creation phase of the VO life cycle. Various approaches to solving the problem of partner selection have been proposed in the literature. The problem has been studied from various dimensions including multi-attribute decision making (MADM), project management, agent-based systems and mathematical programming. Most of the work has its roots in manufacturing industry. The majority of the existing work only explores the partner selection at an individual level, i.e. selecting a suitable partner from a group of potential partners to perform a particular task or role. However, the impact of a potential partner on the overall va or network has not been' considered as an important dimension to the problem, and the impact of characteristics or attributes of a potential partner on the process in which it is involved has not been analysed in detail. To overcome this problem, a Process Performance Evaluation Framework (PPEF) has been proposed. It consists of two parts: a performance model and a performance evaluation methodology. The performance model defines various dimensions and performance indicators that can be used to evaluate the process performance at individual process level as well as overall va level. The performance evaluation methodology is based on system dynamics modelling to model and predict the performance of a particular set of business processes, business rules, participating partners and resources, collectively called the Process Configuration. Each different process configuration presents an alternative set of partners that may become part of a future va. The proposed system dynamics approach for modelling the business processes helps in the evaluation of alternative process configurations by predicting the impact of each partner's contribution on the overall process. The system dynamics model of the future va, which represents the key business processes and their relationships, also provides a feedback structure of various variables that affect the performance of the VO as a whole. Therefore, by simulating the dynamic model of the VO, the performance of each of the alternative process configurations can be evaluated from a holistic point of view. The process configuration predicted to achieve the highest level of performance can be selected as the most suitable VO configuration. Partners in the selected process configuration are thus the most suitable group of partners to form the virtual organisation.
25
Buczkowski, Hubert. "Development of marker vaccines for rinderpest (RPV) and peste des petits ruminants (PPRV) viruses." Thesis, Royal Veterinary College (University of London), 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558958.
26
Sanz, Bernardo Beatriz. "Control of host innate immune (interferon) responses by peste des petits ruminants virus (PPRV)." Thesis, St George's, University of London, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.703281.
Анотація:
Peste des petits ruminants virus (PPRV) produces clinical disease in goats and sheep. PPRV is a morbillivirus, others of which are known to affect the activation of the innate immune response by the actions of their accessory proteins (V&C). A crucial part of normal activation is the induction of interferon β (IFNβ) after pathogen recognition by pattern recognition receptors (PRRs). The presence of viral RNA can be sensed by the cytosolic proteins MDA-5 and RIG-I, starting a signalling cascade that leads to the activation of the IFNβ promoter and the synthesis of IFNβ. The production of IFNβ is a defence mechanism to control the spread of infection to neighbouring cells. Many viruses have evolved to antagonize this cell response. In this thesis I present a study of the induction of IFNβ following PPRV infection in both goat and primate cells, and the effects of infection with PPRV on the induction of IFNβ following MDA-5 and RIG-I mediated activation. Using both reporter assays and direct measurement of IFNβ mRNA, I found that PPRV infection does not induce IFNβ and can block the activation of expression of IFNβ. A study of the interaction of the PPRV accessory proteins with MDA-5 and RIG-I was carried out, including the cloning of goat RIG-I and LGP2. I also generated mutant viruses that lack expression of either accessory protein to characterize the role of these proteins in IFNβ induction during virus infection. Overexpression of V blocks MDA-5 mediated induction of IFNβ, but PPRV lacking V can still block MDA-5 mediated activation of IFNβ. PPRV C bound to neither MDA-5 nor RIG-I, but PPRV lacking C lost the ability to block MDA-5 and RIG-I mediated activation of IFNβ. These results shed new light on the inhibition of the induction of IFNβ by PPRV.
27
Olivati, Clarissa de Almeida. "Estudo das propriedades elétricas e ópticas de dispositivos eletroluminescentes poliméricos." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-08122010-094137/.
Анотація:
Dispositivos eletroluminescentes poliméricos apresentam alto potencial tecnológico, principalmente devido ao fato de ser possível a obtenção de dispositivos flexíveis e de grande área. Apesar disto, ainda existem alguns fatores que limitam a sua aplicação tecnológica, como por exemplo o tempo de vida e a eficiência na emissão dos dispositivos. Alguns métodos têm sido propostos para o aumento destes fatores, entre os quais estão a inserção de camadas transportadoras de elétrons e buracos. Esta tese teve como objetivo principal a busca por métodos que possibilitassem a melhora das propriedades elétricas e/ou ópticas dos dispositivos eletroluminescentes poliméricos (PLEDs). Neste contexto, filmes Langmuir-Blodgett (LB) da camada emissiva e da camada transportadora de elétrons foram aplicados nos PLEDs, devido a reprodutibilidade e ao grau de organização destes filmes, o que possibilita uma emissão polarizada. Além disso, observou-se aumento na injeção eletrônica nos dispositivos com o uso de ionômeros como camada transportadora de elétrons. Por outro lado, a combinação da POMA e ITO como eletrodo transparente no dispositivo com PPV+DBS como camada ativa (ITO/POMA/PPV+DBS/Al) mostrou a diminuição da tensão de operação quando comparado a um dispositivo convencional (lTO/PPV/Al). Os dispositivos foram caracterizados através de medidas elétricas e opto-elétricas.Polymer electroluminescent devices are promising for a number of applications, in particular due to the possibility of obtaining large area, flexible displays. There are, however, major stumbling blocks associated with the short lifetimes and limited efficiency and brightness of light-emitting diodes (LEDs) fabricated with organic molecules in comparison with the inorganic ones. Severa1 methods have been proposed to increase brightness and eficiency, which include the use of electron and/or hole transporting layers adjacent to the electrodes. ln this thesis, we report the study of severa1 methods to improve the efficiency of the polymer light emitting diodes (PLEDs). In this context, Langmuir-Blodgett (LB) films were used in PLEDs, as emitting and electron transport layer, due to the high degree of thickness control, low number of defects, and some degree of organization at the molecular scale. Besides, improvements in electron injection into the emissive layer using ionic polymers (ionomers) as electron-transporting layers were observed. Othenvise, the combination of POMA and ITO as transparent electrode and PPV+DBS as active layer (ITO/POMA/PPV+DBS/A1) leads to a decrease in the operating voltage compared with the conventional PLED, ITO/PPV/Al. The devices were characterized by electrical and opto-electrical measurements.
28
Alves, Marcelo Caetano Oliveira. "Estudo de soluções de MEH-PPV em dosimetria de radiação gama." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-03092008-091923/.
Анотація:
O presente trabalho teve por objetivo o estudo da viabilidade de utilização de soluções de poli[2-metóxi,5-(2-etil-hexiloxi)-p-fenileno vinileno] (MEH-PPV), em diversos solventes tais como CHCl3 (Clorofórmio), diclorometano (CH2Cl2), bromofórmio (CHBr3), dibromometano (CH2Br2), uma mistura de diclorometano (CH2Cl2) e diiodometano (CH2I2) e tolueno (C6H5CH3), como dosímetros de radiações ionizantes. A novidade está no fato de que estes dosímetros têm como principal característica a variação da cor, proporcionando uma medida visual e direta da radiação recebida. Além disso, a sensibilidade dos dosímetros pode ser ajustada por meio da variação da concentração das soluções do polímero. Neste trabalho, foi utilizada a radiação gama, 60Co, para os estudos de viabilidade deste dosímetro. Quando submetidos a certas doses de radiação gama, o polímero estudado sofre alterações em suas propriedades óticas e em sua estrutura molecular. Para avaliar as alterações óticas, foram utilizadas medidas de espectroscopia de absorção UV-Visível (UV-Vis) e fotoluminescência. Também foram avaliadas as alterações na estrutura molecular, como conseqüência da exposição à radiação gama por meio de técnicas como ressonância magnética nuclear (RMN) e cromatrografia de permeação de gel (GPC). Os Resultados obtidos mostraram que a radiação gama, 60Co, promove, de forma indireta, a diminuição do comprimento efetivo da conjugação do polímero, mais provavelmente em decorrência da quebra da cadeia principal do polímero devido às reações com as espécies reativas, possivelmente nos grupamento vinil. Estas quebras resultam em um deslocamento dos picos máximos dos espectros de absorção para regiões de maior energia (blueshift). Estes deslocamentos dependem não somente da dose de irradiação, mas também do solvente utilizado em da concentração da solução.The present work aims the study of the viability of using solutions of poly[2-methoxy-5-(2\'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV), in several solvents such as chloroform (CHCl3), dichloromethane (CH2Cl2), bromoform (CHBr3), dibromomethane (CH2Br2), a mix of dichloromethane (CH2Cl2) and diiodomethane (CH2I2), and toluene (C6H5CH3) as ionizing radiation dosimeters, gamma, in this case. The novelty is in the fact of the dosimeter main characteristic is color change, allowing a visual and direct received radiation measurement. Besides, the sensibility of the dosimeter can be adjusted by the polymer solution concentration variation. In this work, it was used the gamma radiation, 60Co, for the dosimeter viability studies. When exposed to certain doses of this kind of radiation, the studied polymer suffers changes in its optic properties and in its molecular structure. In order to evaluate the optical changes, UV-VIS absorption and photoluminescence spectroscopy measures were performed. Besides, the molecular structure changes, as a consequence of the exposure to gamma radiation, were evaluated by nuclear magnetic resonance (NMR) and Gel Permeation Chromatography (GPC). The results show that the gamma radiation, 60Co, promotes, indirectly, the decrease of the polymer conjugation length probably due the backbone scission caused by reactions with reactive species, probably in the vinyl side groups. These scissions resulted in a blueshift of the absorption spectra maximum peaks. Theses blueshifts depend on the irradiation dose, the used solvent and the solution concentration.
29
Ferreira, Ana Guida Coutinho. "Promoção da eficiência no consumo de energia eléctrica: o caso do plano de promoção da eficiência no consumo." Master's thesis, Instituto Superior de Economia e Gestão, 2010. http://hdl.handle.net/10400.5/2239.
Анотація:
Mestrado em Economia e Políticas PúblicasCom o desenvolvimento económico a estimular a procura de energia, e a existência de barreiras e falhas de mercado que dificultam a eficiência energética, é fundamental a implementação de programas de promoção da eficiência energética e de gestão da procura. Em Portugal, o Plano de Promoção da Eficiência no Consumo de energia eléctrica, que teve a sua primeira edição em 2007, visa promover medidas no âmbito da eficiência energética, mediante um concurso aberto a vários agentes. Este relatório descreve o processo de avaliação das quatro medidas do segmento residencial de 2007, quer a nível ex-ante (aquando da seriação das mesmas para financiamento), quer a nível ex-post (após a implementação). As medidas avaliadas apresentam rácios benefício-custo positivos, demonstrando toda a sua valia económica e social. A grandeza dos números conseguidos reforça assim a ideia de que a promoção da eficiência energética, do lado da procura, se apresenta como uma solução viável na mitigação da dependência dos combustíveis fósseis e do nível de emissões de CO2.
Energy efficiency and demand side management programs are key to cope with increasing energy demand associated with economic growth and with existing barriers to energy efficiency and related market failures. In Portugal, the Plan to Promote the Efficient Consumption of electrical energy, which first took place in 2007, aims to promote energy efficiency measures through a competitive mechanism open to various stakeholders. This report describes the evaluation process for the residential segment used in 2007 both at an ex-ante level (when evaluating financing measures) as well as an ex-post level (following implementation). The measures evaluated show positive cost-benefit ratios, demonstrating their full economic and social value. The size of the figures achieve thus reinforce the idea that promoting energy efficiency, from a demand point of view, is presented as a viable solution in mitigating dependence on fossil fuels and reducing CO2 emissions.
30
Lenihan, Catherine. "Functional characterisation of VAV-interacting Krüppel-like factor (VIK) in breast cancer." Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/24559.
Анотація:
Background. VAV interacting Krüppel-like factor (VIK) is a novel transcription factor. Previously our lab reported a series of breast cancer tumour samples where VIK methylation was associated with an increased risk of recurrence in tamoxifen-treated patients, indicating a role for VIK in ER positive breast cancer and endocrine resistance. Additionally VIK has been shown to be involved in cell cycle regulation, interacting with CDK4 and VAV1. The cyclin D-CDK4/6-Rb pathway is frequently dysregulated in ER positive breast cancer. Combined treatment of palbociclib, a highly selective CDK4/6 inhibitor, with endocrine therapy substantially improved outcome of patients with ER positive metastatic breast cancer. Increasing clinical use means acquired resistance to palbociclib is emerging as a major clinical challenge. Results. VIK was confirmed to be subject to regulation by DNA methylation in breast cancer. VIK methylation correlated to transcriptional silencing of mRNA in both cancer cell lines and primary tumours. To determine the functional significance of loss of VIK expression, VIK was knocked down in unmethylated breast cancer cell lines and a normal breast epithelial cell line. Knockdown resulted in cell death via induction of apoptosis. VIK knockdown altered cell cycle progression from G1 to S phase. Expression of multiple regulatory cell cycle proteins was altered, differentially in normal and tumour cells. Treatment with the CDK4/6 inhibitor, palbociclib, in cells with reduced VIK expression resulted in decreased sensitivity to the drug, inducing a shift in IC50 value towards resistance. In a model of acquired resistance, T47D cells were cultured long-term with palbociclib generating resistant clones. VIK was significantly downregulated in all resistant clones to barely detectable mRNA levels, suggesting a role for VIK in resistance to CDK4/6 inhibition. Conclusion. This PhD has confirmed VIK is a novel epigenetically regulated gene in breast cancer. VIK expression is essential to both normal and tumour breast cell survival and is involved in the regulation of the G1/S phase transition in the cell cycle. Loss of VIK expression potentially contributes to the development of acquired resistance to CDK4/6 inhibitors.
31
Postacchini, Bruna Bueno. "Fotofísica em heteroestruturas contendo o polímero emissor PPV e espécies supressoras." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-30012009-114630/.
Анотація:
A compreensão dos caminhos de desativação não radiativa em polímeros conjugados é fundamental para o uso desses materiais em dispositivos luminescentes, células fotovoltaicas e sensores. Nesta tese, os processos não radiativos em filmes automontados de polímero luminescente foram investigados via análise da supressão de intensidade de fotoluminescência, utilizando a técnica de fluorescência estacionária, e através da medida do tempo de vida do estado excitado com fluorescência resolvida no tempo em arranjo de contagem de fótons. A camada emissiva constituída por poli(p-fenileno vinileno) (PPV) obtido da conversão térmica do precursor poli(cloreto de xilideno tetraidrotiofeno) (PTHT) apresentou tempos de vida entre 150 e 250 ps, e fraca dependência com o comprimento de onda de detecção da emissão. Na presença de uma monocamada contendo azocorante Vermelho do Congo (CR) ou ftalocianina tetrassulfonada de níquel (NiTsPc) atuando como receptor de energia foi observada supressão da fluorescência e encurtamento do tempo de vida (50-100ps). À medida que se aumenta a distância entre as camadas de doador e receptor via interposição de bicamadas de espaçador, a dinâmica do sistema tende à dinâmica de decaimento do estado excitado do PPV na ausência de receptor. A dependência da eficiência com a distância 1/r2 ou 1/r3 apontam para transferência de energia ressonante (RET) típica da interação plano-plano ou plano-camada. Os processos não radiativos foram também estudados em função da diluição de segmentos PPV dispersos em matriz de polieletrólito poli(cloreto de dodecildimetilamônio) PDAC. A diluição dos segmentos conjugados aumenta a eficiência quântica de emissão, torna o mecanismo de desativação mais lento (500 ps) e diminui a dependência do tempo de vida com o comprimento de onda de detecção, devido à menor eficiência dos mecanismos de desativação não radiativa. Na presença de uma camada receptora, a eficiência de transferência de energia é maior para amostras com segmentos mais diluídos indicando que esse mecanismo compete com os processos internos à própria camada emissiva. O tempo de vida aumenta em filmes com mais baixo grau de conjugação e a dependência com o comprimento de onda de emissão é mais forte. Em resumo, a técnica de automontagem se mostrou adequada para obter filmes com propriedades fotofísicas controláveis no nível molecular, que puderam ser estudadas com espectroscopias de fluorescência.Understanding the pathway of excitation in conjugated polymers is important for using these materials as active layer in devices, photovoltaic cells and sensors. In this thesis, non-radiative processes in layer-by-layer (LbL) films were investigated with measurements of fluorescence quenching in steady-state fluorescence spectroscopy and of the singlet excited state lifetime using time-resolved fluorescence spectroscopy in a single photon counting (SPC) apparatus. The emissive layer of poly(p-phenylene vinylene) (PPV) obtained via thermal conversion of the soluble precursor poly(xylylidene tetrahydrothiophenium) chloride (PTHT) showed lifetime 150-250 ps and weak dependence on the emission wavelength. In the presence of an acceptor layer of either Congo Red (CR) or nickel tetrasulfonated phthalocyanine (NiTsPc) the PL intensity was quenched and the lifetime was shorter (50 -100 ps). Upon increasing the distance between the energy donor (PPV) and acceptor layers by interposing bilayers of inert polyelectrolytes the dynamics tended to the PPV dynamics. The distance-dependence of the energy transfer efficiency (1/r2 or 1/r3) points to a resonant process (RET) with a plane-to-plane or plane-to-slab interaction. The non-radiative processes were also studied for varying dilutions of the PPV segments in a matrix of the polyelectrolyte poly(dodecyl methylamonium chloride) (PDAC). This dilution increased the quantum efficiency and led to longer lifetimes (500 ps) owing to a less effective non-radiative energy transfer. When an energy acceptor layer is present, energy transfer is more efficient for the most diluted systems, indicating that such transfer competes with internal processes in the emissive layer. The lifetime increased in films with low degree of conjugation, for which there was a stronger dependence on the emission wavelength. It is concluded that the LbL methodology was suitable to obtain photophysical film properties that could be controlled at the molecular level, and investigated with varied fluorescence spectroscopies.
32
Marconi, Flávia Maria. "Síntese e caracterização de polímeros com propriedades eletroluminescentes." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-14112014-102419/.
Анотація:
Durante este trabalho foram sintetizados e caracterizados três derivados dialcoxilados do poli(p-fenileno-vinileno) que diferem entre si pelo tamanho de uma das cadeias laterais: o poli(2-metoxi-5-hexiloxi-p-fenileno-vinileno), MH-PPV, o poli(2-metoxi-5-dodecoxi-p-fenileno-vinileno), MD-PPV e o poli(2-metoxi-5-hexadecoxi- p-fenileno-vinileno), MHd-PPV. Esses polímeros apresentam propriedades eletroluminescentes e podem ser utilizados em dispositivos emissores de luz. A síntese consiste de três etapas: síntese do éter aromático; bisclorometilação do éter aromático, gerando o monômero; e polimerização. A maior diferença no processo de síntese foi observada na obtenção do monômero, sendo necessário um maior excesso de reagente e maiores tempos de reação para a obtenção do monômero do MD-PPV e do MHd-PPV do que para o MH-PPV. Todos os produtos foram caracterizados principalmente por espectroscopia na região do infravermelho, FTIR, e por Ressonância Magnética Nuclear de próton e carbono 13. A estrutura química dos polímeros foi confirmada por FTIR e as massas moleculares foram determinadas por Cromatografia de Exclusão por Tamanho, revelando uma alta polidispersividade e valores de massa molecular ponderal média (Mw) da ordem de 105. A análise térmica revelou valores de temperatura de transição vítrea, Tg e amolecimento, Ts, acima de 100oC, e ainda temperaturas de decomposição acima de 400oC para os três polímeros. O MHd-PPV, apresentou, além da Tg, uma transição em tomo de 50oC que pode estar relacionada à fusão das cadeias laterais. Filmes dos três polímeros preparados a partir de diferentes solventes apresentaram diferentes morfologias, observadas por Microscopia de Força Atômica, posições de máxima absorção (500-520 nm) e emissão (585-600 nrn) com pequenas variações e processos de fotodegradação com diferentes características, em função do solvente utilizado. Assim, as diferentes cadeias laterais apresentaram efeitos principalmente sobre características como temperatura de transição vítrea e morfologia dos filmes poliméricos, e, em consequência desta última, sobre o formato dos espectros de emissão e sobre o processo de degradaçãoIn this work, three dialkoxy derivatives of poly(p-phenylenevinylene),which differs from each other by the size of the side chain, were synthesized and characterized: the poly(2-methoxy-5-hexyloxy-p-phenylenevinylene), MH-PPV, the poly(2-methoxy-5-dodecoxy-p-phenylene-vinylene), MD-PPV and the poly(2-methoxy- 5-hexadecoxi-p-phenylene-vinyleno), MHd-PPV. These polymers have electroluminescent properties and can be used in light emitting devices. The synthesis consists in three steps: synthesis of aromatic ether, bischloromethylation of the ether yielding the monomer, and polymerization. The major difference regarding the synthesis processes lies on the monomer synthesis. A larger excess of reagents and longer reaction times were necessary to obtain the MD-PPV and MHd-PPV than that used to obtain the MH-PPV. All the products of the two first steps were characterized mainly by FTIR and NMR (proton and carbon 13). The chemical structures of the polymers were confirmed by FTIR and the molar masses determined by characterized by Size Exclusion Chromatography, revealing a high polydispersity and values of mean mass molecular weight (Mw) around 105. The thermal analysis presented values of glass transition temperatures, Tg, and softening, Ts, above 100 oC, and decomposition temperatures above 400oC for the three polymers. The MHd-PPV, presented, besides the Tg, a transition in 50oC, which may be related to the melting of the side chain. Films of the three polymers prepared from different solvents presented different morphologies, as observed by Atomic Force Microsocopy, slightly different absorptions (500-520 nm) and emission (585-600 nm) maxima and different photo-degradation processes depending on the solvent used to prepare the films. Therefore, the different size of the side chain presented effects mainly on characteristics as thermal transitions and film morphologies, and, in consequence of the late, on the shape of the emission and on the degradation properties
33
Todescato, Francesco. "Functional dielectric/semiconductor and metal/semiconductor interfaces in organic field-effect transistors." Doctoral thesis, Università degli studi di Padova, 2007. http://hdl.handle.net/11577/3425125.
Анотація:
The work presented in this thesis focuses on the investigation of two interfaces which play a crucial role in the physics of organic electronic devices: the dielectric/organic semiconductor and the organic semiconductor/metal ones.
Regarding the dielectric/OS interface, we have deeply investigated the relationship between the SiO2 cleaning protocol or treatment and the electrical response of OFETs based on two PPV semiconducting polymers (MEH-PPV and OC1C10-PPV) and on a quarterthiopene derivative small molecule (DHCO-4T).
Regarding the OS/metal interface, we investigated the electrical performances of PPV and DHCO-4T based OFETs with different metal contacts.
34
Cera, Alexandre Manuel Gomes. "Certificados brancos para o caso português : análise económica e contributos para a sua aplicação e implementação." Master's thesis, FEUC, 2012. http://hdl.handle.net/10316/20102.
Анотація:
Dissertação de mestrado em Gestão, apresentada à Faculdade de Economia da Universidade de Coimbra, sob a orientação de Patrícia Pereira da Silva e Nivalde José de Castro.Dadas as preocupações ambientais e energéticas e os objetivos europeus estabelecidos para 2020, entre os quais o aumento em 20% da eficiência energética (EE), os decisores públicos procuram novos instrumentos que permitam alterar e/ou otimizar os padrões de consumo de energia do lado da procura. Um instrumento de política energética e de EE que tem ganho atenção dos decisores públicos são os Certificados Brancos (CBs). Um esquema de CBs, sendo um instrumento baseado no mercado, está alinhado com a desregulação do lado da oferta nos mercados energéticos como permite minimizar distorções de mercado e refletir com maior precisão as preferências dos consumidores. O objetivo último da presente dissertação é estabelecer uma proposta conceptual da configuração de um esquema de CBs transacionáveis a implementar em Portugal. Neste sentido, procede-se a um estudo com base numa carteira de cinco critérios pré-selecionados, acerca da viabilidade económica dos CBs; da experiência em esquemas de CBs transacionáveis europeus, cuja análise descritiva foi complementada com um estudo comparativo dos esquemas em questão nos países selecionados (e.g. Itália, França, Grã-Bretanha); da incidência energética de um esquema de CBs em Portugal; da integração de um esquema de CBs na política energética nacional e europeia, abarcando a questão da liberalização dos mercados de eletricidade e gás natural; e, por fim, do enquadramento de um esquema de CBs com a experiência portuguesa em EE, nomeadamente com o Plano Nacional de Ação para a Eficiência Energética (PNAEE) e o Programa de Promoção da Eficiência no Consumo de Energia Elétrica (PPEC), incluindo a atuação das entidades que os coordenam. Para além de ser um instrumento custo-eficaz, um esquema de CBs transacionáveis, tem a característica exclusiva, sob determinadas condições, de simultaneamente incentivar melhorias de EE, e reduzir o rebound effect e o efeito de free rider. Esta conclusão, no conhecimento dos autores, é única na literatura da área. Com base nas elações que se teceram, apoiadas na abordagem metodológica adotada, sugeriram-se alguns aspetos que se tomaram como mais relevantes na persecução do objetivo estabelecido (e.g. natureza e objetivo de poupanças energéticas; elegibilidade). Crê-se que um esquema de CBs transacionáveis acrescentará valor ao portefólio de instrumentos de política energética portuguesa.
Given the environmental and energy concerns, and the European targets set for 2020, including the 20% increase in energy efficiency (EE), policy makers are seeking new tools to change and/or optimize current patterns of demand side energy consumption. An energy policy and EE instrument which has gained the attention of policy makers is White Certificates (WCs). A scheme of WCs, being a market-based mechanism, is aligned with deregulation of the supply side of the energy market, and allows to minimise distortions in the market and to more accurately reflect consumer preferences. The ultimate objective of this dissertation is to establish a conceptual proposal of the design of a tradable WCs scheme to implement in Portugal. In this sense, we proceed with a study based on a portfolio of five pre-selected criteria, about the economic viability of WCs; the experience of European tradable WCs schemes, whose descriptive analysis was complemented with a comparative study of the schemes in selected countries (e.g. Italy, France, Great Britain); the energetic scope of a WCs scheme in Portugal; the integration of a WCs scheme in national and European energy policies, covering the issue of electricity and natural gas markets liberalization; and finally, the frame of a WCs scheme with the Portuguese experience in EE, in particular the National Action Plan for Energy Efficiency (PNAEE) and the Program for Promoting Efficiency in Electricity Consumption (PPEC), including its’ coordinator entities performance. Besides being a cost-effective instrument, a tradable WCs scheme has the exclusive feature, under certain conditions, of simultaneously stimulating improvements in EE while reduces the rebound and free rider effects. This conclusion, in the authors' knowledge, is unique in the literature. Based on our elations, supported by the adopted methodological approach, we suggest some aspects that have been taken as more relevant in pursuing our objective (e.g. energy savings nature and target; eligibility). We believe that a tradable WCs scheme will add value to the Portuguese energy policy instruments portfolio.
35
Pu, Zhengxiang. "A Dynamic Model of the Human/Cooling System/Clothing/Environment System." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2077.
Анотація:
The human body compensates well for moderate climatic heat stress, but artificial environments often block or overwhelm physiological defense mechanism. Personal protective equipment (PPE) is one of sources of heat stress. It protects individual from chemical, physical, or biological hazards, but the high thermal insulation and low vapor permeability of PPE may also lead to substantial heat stress. Personal cooling is widely used to alleviate heat stress, especially for those situations where ambient environmental cooling is not economically viable or feasible. It is important to predict the physiological responses of a person wearing PPE with personal cooling to make sure that the individual is free of heat stress, as well as any additional discomfort that may occur. Air temperature, radiant temperature, humidity and air movement are the four basic environmental parameters that affect human response to thermal environments. Combined with the personal parameters of metabolic heat generated by human activity and clothing worn by a person, they provide the six fundamental factors which define human thermal environments. If personal cooling system is available, the fluid flow speed, cooling tube distribution density and fluid inlet temperature have significant effects on the human thermal comfort. It is impractical to evaluate the problem experimentally due to too many factors involved. A thermal model was developed to improve human body thermal comfort prediction. The system researched includes human body, personal cooling system, clothing and environment. An existing model of thermoregulation is taken as a starting point. Changes and additions are made to provide better prediction. Personal cooling model was developed and it includes liquid cooling model, air cooling model and ice cooling model. Thermal resistance networks for the cooling system are built up; additionally a combined model of heat and mass transfer from cooling garment through clothing to environment is developed and incorporated into the personal cooling model and thermoregulatory model. The control volume method is employed to carry out the numerical calculation. An example simulation is presented for extra-vehicular activities on Mars. The simulation results agree well with available experimental data, though a small discrepancy between simulation results and experimental data is observed during the beginning of the cooling process. Compared with a water cooling lumped model, the thermal model provides a much better prediction. For water cooling, parametric study shows that the cooling water inlet temperature and liner thermal resistance have great effects on the maximum exposure time; PPE resistance and cooling water flow rate do not have much impact on the maximum exposure time. For air cooling, cooling air flow rate, inlet temperature, relative humidity and liner resistance have great effects on the maximum exposure time.Ph.D.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Mechanical Engineering
36
Cossiello, Rafael Di Falco 1980. "Eletroluminescencia e morfologia de blendas polimericas : copolimeros ionicos de SAA e blendas com MEH-PPV." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249467.
Анотація:
Orientador: Teresa Dib Zambon AtvarsTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
Made available in DSpace on 2018-08-10T13:29:22Z (GMT). No. of bitstreams: 1 Cossiello_RafaelDiFalco_D.pdf: 19466365 bytes, checksum: 4613f44ad7300b66e793fa6de43b2c82 (MD5) Previous issue date: 2007
Resumo: O copolímero SAA (poli(estireno-co-ácido acrílico-co-1-metacrilato de pirenilmetila)) foi sintetizado por via radicalar em agua e caracterizado por analises termicas (DSC, TGA), espectroscopicas (NMR C e H, UV-VIS, FTIR, fluorescência estacionária e resolvida no tempo) e elétricas (eletroluminescência). As blendas com poli[2-metóxi-5-(2¿-etilóxi)-p-fenilenovinileno] MEH-PPV foram estudadas desde 0,01; 0,05; 0,10; 0,50; 1,0; 10,0; 25; 50; 75 e 90 (% em massa) de MEH-PPV em SAA para ánalise da evolucao da morfologia por microscopia óptica, de fluorescência e eletrônica de varredura em espessuras de 70 mm (fratura criogênica) e 70 nm (espessura do dispositivo). Em baixas concentracões os domínios de MEH-PPV se apresentam em forma de núcleos dispersos e empacotados e conforme se aumenta a concentracao de MEH-PPV, observa-se que há a coalescência destes núcleos até a formação de uma fase interconectada de uma rede tridimensional. As medidas de difração à altos angulos mostram que há uma preferência de orientação do MEH-PPV ao longo do substrato e nao influencia a isotropia do SAA devido a baixa miscibilidade entre estes polímeros. As unidades de 1-pirenil metila foram utilizadas para avaliar a polaridade do microambiente e o mecanismo de transferencia de energia entre o doador (SAA) e o receptor (MEH-PPV). A dependência do tempo de fluorescência das unidades 1-pirenilmetila com a concentracao do MEH-PPV fornece subsídios para concluir que ocorre interpenetração de cadeias e, portanto uma baixíssima solubilidade entre os dois polímeros. O melhor desempenho de eletroluminescência foi do dispositivo preparado a partir da mistura 50:50 de MEH-PPV:SAA, cuja corrente elétrica foi aumentada em 2,5 vezes e a luminância em 4 vezes se comparado com o dispositivo de MEH-PPV puro. A morfologia de fase interconectada se mostrou importante para um melhor processo de transporte de cargas. O copolímero de SAA permitiu uma melhor injeção de cargas devido aos grupos carboxila presentes das unidades de ácido acrílico
Abstract: The copolymer SAA poly(styrene-co- acrylic acid -co-1-pyrenylmethyl methacrylate) was synthesized by radical emulsion in water and characterized by thermal analyses (DSC, TGA), spectroscopic (NMR 13C and 1:00, UV-VIS, FTIR, stationary and time-resolved fluorescence) and electric (electroluminescence). The blends with poly[2-methoxy-5(2'ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) were studied from 0. 01; 0. 05; 0.10; 0.50; 1.0; 10.0; 25; 50; 75 and 90 (% in mass) of MEH-PPV in SAA to analyze the morphology evolution by optical, epifluorescence and electronic microscopy. The films were prepared in two thicknesses: one around 70 mm to be analyzed by cryogenic fractures and 70 nm, to be comparable with the device thickness. In low concentrations the domains of MEH-PPV appears dispersed nuclei and accrete when the concentration of MEH-PPV is increased forming an interconnected phase. The diffraction measures (WAXD) show a preference orientation of MEH-PPV along the substrate plane and it do not influences the SAA due the low miscibility between each other. The increase of the MEH-PPV concentration showed a redshift on electroluminescence spectrum due the inner filter and auto-absorption and re-emission effects. The units of 1-pyrenylmethyl were used to evaluate the polarity of the microenvironment and the mechanism of energy transfer of among the donor (SAA) and the acceptor (MEH-PPV). The timedependence of fluorescence with the increase of MEH-PPV concentration show that occurs an chain interpenetration following the fluorescence non-radiative energy transfer model. The best electroluminescent device was prepared using the mixture 50:50 of MEH-PPV:SAA. The interconnected phases are important for a better process of charge transport. The copolymer SAA allowed for a dilution effect avoiding the aggregation process and facilitating the charge injection processes. This technology of polymeric blends gave good results the increase of the luminance intensity and reduction of the voltage operation
Doutorado
Físico-Química
Doutor em Ciências
37
Sarnecki, Greg. "Studies in soluble conjugated polymers." Thesis, University of Cambridge, 1994. https://www.repository.cam.ac.uk/handle/1810/272769.
38
Halliday, David Alan. "The synthesis and characterisation of poly(p-phenylenevinylene)s." Thesis, University of Cambridge, 1992. https://www.repository.cam.ac.uk/handle/1810/272381.
39
Sorce, Steven R. "The military housing problem Public Private Venture (PPV) and complete privatization alternatives /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA379322.
Анотація:
Thesis (M.S. in Management) Naval Postgraduate School, June 2000.Thesis advisor(s): Simon, Cary A.; . Eaton, Donald R. "June 2000." Includes bibliographical references (p. 73-74). Also available in print.
40
Kuch, Serena [Verfasser], Matthias [Akademischer Betreuer] Rehahn, and Stefan [Akademischer Betreuer] Immel. "Neue PPV-Derivate auf ungewöhnlichen Wegen / Serena Kuch ; Matthias Rehahn, Stefan Immel." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2019. http://d-nb.info/1176702017/34.
41
Faleiros, Marcelo Meira. "Espectroscopia ultrarrápida do polímero semicondutor luminescente MEH-PPV com excitação no ultravioleta." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-06122012-084909/.
Анотація:
A indústria optoeletrônica passa por um período de transformação em que os materiais inorgânicos estão sendo substituídos pelos orgânicos, oligômeros e polímeros, na fabricação de alguns tipos de dispositivos. No entanto, fatores como baixa eficiência e tempo de vida impedem que os aparelhos com base nos polímeros entrem definitivamente no mercado. Para resolver estas questões, é necessário um conhecimento profundo da estrutura eletrônica desses materiais. Apesar do avanço científico, ainda existem pontos a esclarecer. Por exemplo, não existe um consenso sobre a natureza das excitações óticas primárias e dos processos não radiativos nos polímeros conjugados, principalmente com excitação no ultravioleta. Tais processos limitam a eficiência e podem influenciar nos processos fotoquímicos, determinando o tempo de vida de um dispositivo. Esses fenômenos ocorrem em alguns picossegundos e, portanto, a espectroscopia ultrarrápida é a técnica mais adequada para o seu estudo. Neste trabalho, foi implementado o aparato para espectroscopia de bombeio e prova em filmes finos de polímeros conjugados, no qual podem ser usados dois métodos de aquisição de dados, sensível à fase e pulso-a-pulso. O primeiro é o método padrão citado na literatura, no qual o feixe de excitação é modulado por um chopper e os sinais são medidos por amplificadores lock-in. No segundo, o condicionamento de sinais é feito por circuitos amplificadores e o processamento dos sinais é feito pulso-a-pulso. É um método que a princípio fornece melhor estatística, pois as flutuações do laser são normalizadas pulso-a-pulso, e não na média. Além disso, apresenta menor custo e torna o experimento de bombeio e prova mais simples, pois os únicos procedimentos críticos passam a ser a sobreposição dos feixes na amostra e a determinação do atraso zero entre bombeio e prova. Foi projetado e construído o circuito eletrônico de condicionamento de sinais e o software de aquisição foi desenvolvido em linguagem LabVIEW. Entretanto, o método pulso-a-pulso forneceu uma sensibilidade inadequada para o estudo de filmes poliméricos, (ΔT⁄T ~ 0,7%, limitada pelo ruído elétrico na amplificação dos pulsos detectados), em contraste com ΔT/T ~ 0,1% que foi alcançada pelo método sensível à fase. Desta maneira, foi usado o último método para o estudo da evolução do espectro e da dinâmica de emissão estimulada de um filme de MEH-PPV, com excitação no visível e no ultravioleta, permitindo o estudo da dinâmica de relaxação dos estados de mais alta energia. Os resultados no visível são compatíveis com os da literatura, o que demonstra a confiabilidade do aparato quanto à sensibilidade e resolução temporal e espectral. Os resultados com excitação no UV indicam que a transferência de energia de bandas mais energéticas para a banda π - π∗ (conversão interna) ocorre em aproximadamente 300 fs, confirmando as suposições da literatura quanto à relaxação energética ultrarrápida (regra de Kasha), além de sugerir a existência de bandas ainda mais energéticas do que as já conhecidas. Pretende-se futuramente determinar a eficiência de tal transferência energética, pois ela pode ser um fator limitante na eficiência de fotoluminescência em polímeros conjugados com excitação no ultravioleta.The optoelectronics industry is currently undergoing a transition period in which inorganic materials are being replaced by organic materials, oligomers and polymers, in the fabrication of some types of devices. However, factors such as low efficiency and low lifetime prevent polymer based devices on entering the market definitely. The solution of these issues requires a thorough knowledge of the electronic structure of these materials, but despite of scientific advances, there are still points to be clarified. For example, there is no consensus on the nature of the primary optical excitations and non-radiative processes in conjugated polymers, specially with ultraviolet excitation. Such processes limit the efficiency and can influence the photochemical processes, determining the device lifetime. These phenomena occur on a femtosecond timescale and therefore, ultrafast spectroscopy is the most appropriate technique for their study. In this work, we implemented the apparatus for pump-probe ultrafast spectroscopy on thin films of conjugated polymers, which can be used with two methods of data acquisition, phase-sensitive and shot-by-shot. The first is the standard method reported in the literature in which the excitation beam is modulated by a chopper and the signals measured by lock-in amplifiers. In the second, the detector signal conditioning is done by conventional amplifier circuits, followed shot-to-shot signal processing. This method provides the best statistics, in principle, because the laser fluctuations are normalized for each pulse, instead of using the average. In addition, the apparatus has a lower cost and the experiment is simpler, having as critical procedures the alignment of the beams on the sample and the determination of zero delay, with all other procedures done via software. The electronic circuitry for signal conditioning was designed and built and data acquisition software that enables measurements with both methods was developed in the LabVIEW programming language. However, the shot-by-shot method provided an inadequate sensitivity for the study of polymeric films (ΔT⁄T ~0.7%, limited by electronic noise in the amplification of detector signals), compared with ΔT⁄T ~ 0.1%, which was achieved by the phase sensitive method, and was the goal at the beginning of the project. Thus, the latter method was used to study the evolution of the spectrum and dynamics of stimulated emission of a film of MEH-PPV, with excitation in the visible and UV, allowing the study of the dynamics of higher lying electronic states. The results in the visible are consistent with those reported in the literature, which demonstrates the performance of the apparatus with respect to sensitivity and time/spectral resolution. The results with UV excitation indicate that the energy transfer among the more energetic bands to the π - π* band (internal conversion) occurs in about 300 fs, confirming the assumptions of the literature on the ultrafast energy relaxation processes (Kashas rule), besides suggesting the existence of even more energetic bands than those currently known. As future work, we plan to measure the efficiency of this energy transfer process, since it may be the limiting step in determining the overall photoluminescence efficiency of conjugated polymers with ultraviolet excitation.
42
Thamyongkit, Patchanita. "Synthesis and Characterization of Pyrazine and Phthalocyaninatonickel (II) Substituted PPV Analogous Oligomers." [S.l. : s.n.], 2002. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9909232.
43
Martschick, Anja [Verfasser]. "Pathogenese und Prävention der Anthrazyklin-induzierten PPE : eine prospektive Studie / Anja Martschick." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2010. http://d-nb.info/1024502171/34.
44
Campos, Patrícia Bueno de. "Síntese e caracterização de derivados do poli(fenileno-vinileno) com diferentes massas molares." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-14112014-095557/.
Анотація:
Os polímeros com propriedades luminescentes, e mais especificamente, os eletroluminescentes, tem atraído muita atenção devido a sua possível aplicação em dispositivos ópticos e eletrônicos do tipo LEDs (light-emitting diodes). Grande parte das pesquisas realizadas no campo da eletroluminescência se baseia em estudos sobre poli (arilenos-vinilenos), como o poli-(p-fenileno vinileno), PPV, e seus derivados. No processo de polimerização de tais polímeros, a influência de algumas variáveis são importantes em suas propriedades finais. Este trabalho descreve a exploração da influência de diversas variáveis no processo de polimerização do derivado do PPV, o poli-(2-metoxi-5-hexiloxi-p-fenileno-vinileno) MH-PPV. Além disso, com o intuito de verificar a influência da presença de aditivos na massa molar dos polímeros foram realizadas polimerizações utilizando-se os aditivos 4-metoxifenol, cloreto de tercbutila e cloreto de benzila durante o processo de polimerização. Também foram realizados estudos sobre o modo de adição e temperatura de polimerização utilizando o aditivo cloreto de benziIa. Todos os produtos foram caracterizados por HPSEC (Cromatografia de Exclusão por Tamanho) para determinação das massas molares dos polímeros. Observou-se que a temperatura e a velocidade de adição da base no meio reacional são variáveis que influenciam significativamente no processo de polimerização e, conseqüentemente, na distribuição na massa molar dos polímeros. Foi constatado que o uso de aditivos no processo de polimerização previne a formação de géis; fornece polímeros com baixa massa molar, aumentando a solubilidade dos polímeros em solventes orgânicos como clorofórmio e THF. A análise térmica dos polímeros revelou que além da Tg em tomo de 160oC, todos os polímeros apresentaram uma transição em tomo de 75oC. Os espectros de absorção e emissão não foram afetados de forma significativa dentro dos valores de massas molares médias obtidas. Foi possível também obter uma relação entre os valores de massa molar obtidos por HPSEC e valores de viscosidade relativa, que pode ser utilizada para estimar valores de Mw através de medidas de tempo de escoamentoElectroluminescent polymers have been widely investigated due to its potential applications in optoelectronic devices such as polymer light-emitting diodes (PLEDs). Most of the polymers suitable for application in PLEDs are related to the poly(arylenes-vinylene) polymers, including the poly(p-phenylene-vinylene) (PPV) and its derivatives, which are of special interest. Such materials can exhibit significant differences on their final properties upon changes on specific synthesis parameters. In this work it is described the influence of three different additives, viz. 4-methoxyphenol, terc-butyl chloride and benzyl chloride, on the polymerization process of the derivative poly(2-methoxy-5-hexyloxy-p-phenylenevinylene) MHPPV. Size Exclusion Chromatography analyses revealed that the type and rate of incorporation of the additives to the polymerization reaction largely affects the molecular weight of the polymers. In addition, it was observed that the use of additives leads to the synthesis of low molecular weight polymers, increasing their solubilities in common organic solvents, eg. chloroform and tetrahydrofuran. The glass transition temperature (Tg) of the polymers was determined by differential scanning calorimetry (DSC) to be ca. 160oC. Interestingly, all the polymers presented an additional transition point at ca. 75oC. Neither the electronic absorption nor the emission spectra were affected by the differences on the molecular weight of the polymers. Finally, it was possible to establish correlations between the molecular weight analyses (from HPSEC) and viscosity experiments, which can be useful for Mw determination
45
Mantip, Samuel Elias Lashat. "Molecular characterisation of peste des petits ruminants viruses in sheep and goats from Nigeria." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/40708.
Анотація:
Peste des petits ruminants virus (PPRV) belongs to the family Paramyxoviridae and genus
morbillivirus. It is a highly contagious, fatal and economically important viral disease of small
ruminants that is still endemic and militate against the production of sheep and goats in
Nigeria. It is a notifiable disease according to the World Organization for Animal Health
(Office International des Epizooties). In this study, a molecular analysis of PPRV from sheep
and goats from recent outbreaks across the different regions of Nigeria was carried out. The
aim was to describe the viral strains and the movement of the virus within the country
compared to other endemic areas of the world. This was carried out through tissue and
swab samples collected from sheep and goats in various agro-ecological zones of
Nigeria.The evolution and relationship of earlier PPRV strains/isolates and those circulating
and causing recent outbreaks was determined by sequencing of the nucleoprotein (N)-gene.
Twenty tissue and swab samples from apparently healthy and sick sheep and goats were
collected randomly from each of three states of each of the six agro-ecological zones visited.
A total of 360 samples were collected. A total of 35 samples of 360 (9.7 %) tested positive by
RT-PCR, of which 25 were from oculo-nasal swabs and 10 were from tissue samples (Table
4.2). Phylogenetic analysis was carried out using the N-gene sequences of the PPRV amplicons.
Alignment of the sequences and related sequences from GenBank and neighbor-joining
phylogenetic analysis using PAUP identified four different lineages, i.e. lineages I, II, III and
IV. Interestingly, the Nigerian strains described in this study grouped in two separate major
lineages i.e. lineages II and IV. Strains from Sokoto, Oyo, Plateau and Ondo states grouped
according to the historical distribution of PPRV together with the Nigerian 75/1 strain of
lineage II, while other strains from Sokoto, Oyo, Plateau, Akwa-Ibom, Adamawa, Kaduna,
Lagos, Bauchi, Niger and Kano states grouped together with the East-African and Asian
strains of lineage IV. This finding suggests that both lineages II and IV strains of PPRVs are circulating presently in Nigeria, contrary to an earlier publication which indicated that only
strains of lineage II were circulating in the country (Shamaki, 2002).Dissertation (MSc)--University of Pretoria, 2013.
gm2014
Veterinary Tropical Diseases
unrestricted
46
Faceto, Angelo Danilo. "Simulação dos processos de migração e relexação energética em sistemas orgânicos pi-conjugados emissores de luz." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-06092007-104908/.
Анотація:
Neste trabalho, o método de Monte Carlo é utilizado para simular o processo de difusão espectral da excitação em um sistema polimérico emissor de luz. A metodologia utilizada incorpora a relaxação energética intramolecular, a migração de energia incoerente entre segmentos conjugados e o processo final que pode ser radiativo (luminescência) ou não-radiativo através de centros supressores da excitação (armadilhas ou defeitos). O principal objetivo é comparar os resultados da simulação e de experimentos envolvendo medidas de absorção, de excitação óptica e de luminescência realizadas no IFSC ao longo dos últimos anos ou provenientes da literatura especializada. Além disso, a simulação pretende elucidar a natureza dos processos fotofísicos em semicondutores orgânicos e testar a validade de teorias analíticas existentes, o que é essencial para a aplicação dessa classe de materiais como dispositivos no futuro. Especial atenção é dada na análise do comportamento temporal da luminescência em sistemas em que o acoplamento dipolar na transferência de energia é realizado entre uma matriz de segmentos conjugados e moléculas aceitadoras (impurezas ou defeitos) distribuídas aleatoriamente. A comparação dos resultados da simulação com os resultados experimentais permitiu comprovar a validade do modelo, do programa utilizado e entender melhor características de parâmetros não conhecidos em polímeros conjugados, como a distribuição energética dos estados eletrônicos e a distribuição de centros supressores de luminescência. Foi possível reproduzir com sucesso os espectros de luminescência, de absorção e de excitação seletiva observados experimentalmente em polímeros conjugados descritos na literatura. Além disso, a simulação permitiu explicar resultados relacionados à diminuição da eficiência da luminescência, ao alargamento e ao deslocamento para o azul das linhas espectrais de emissão de polímero conjugado com o aumento da densidade. Foram obtidas as curvas características de eficiência quântica com a variação da energia de excitação e as características não exponenciais das curvas de intensidade de emissão no tempo. Por fim, foi possível estudar os processos fotofísicos envolvidos em heteroestruturas orgânicas com controle a nível molecular das propriedades de emissão a partir dos processos de transferência de energia tipo Förster (dipolo-dipolo) entre polímeros emissores e azocromóforos. As mudanças dos processos fotofísicos do polímero luminescente se fazem pelo controle posicional/orientacional entre camadas doadoras compostas por moléculas do polímero emissor e camadas receptoras à base de azocorante (receptor).In the present work, the Monte Carlo method is employed to simulate the excitation spectral diffusion process in light emitting polymeric systems. The methodology employed a competition among the internal intra-molecular vibrational relaxation, the inter-molecular incoherent energy transference via Förster mechanism and the final process that may be a radiative emission or a non radiative relaxation through a suppression center. This work main objective is to compare the simulation results with the experiments of absorption, optic excitement and luminescence carried on the IFSC throughout the last years or proceeding from specialized literature. Moreover, the simulation intends to elucidate the nature of the photophysical processes in organic semiconductors and to test the validity of existing theories, what it is essential for the application of this branch of materials as devices in the future. Special attention is given in the analysis of the behavior of the time-resolved luminescence in systems where the energy transfer is carried through a matrix of conjugated segments distributed randomly and acceptor molecules (impurities or defects) coupled by dipole interaction. The comparison of the simulation results with the experimental ones allowed to prove the validity of the model, the used program and to better understand characteristic of parameters for conjugated polymers which are still studied. Different the energy distributions of electronic states, molecular position and orientation are used in order to simulate molecular configurations obtained by different sample preparation methodologies and luminescence suppressor centers. With the simulation, it was possible to reproduce with success the experimental spectra of luminescence, absorption and selective excitation measurements in polymers conjugated described in literature. Besides, the simulation allowed to explain resulted related to the decrease of luminescence efficiency with the increase of the energy of the excitation light, as well as the blue shift and broadening of the spectral lines of conjugated polymer emission with the increase of the density. The characteristic curves of quantum efficiency with the variation of the excitation energy and the not exponential characteristics of the time solved emission intensity curves have been reproduced. Finally, it was possible to study the photophysical processes present in organic heterostructures having molecular level control of the properties of emission via changing the Förster type energy transfer processes between emitting polymers and an azodye. The control photophysical process of the luminescent polymer was accomplished by changing both the orientation and position of the azomolecule in an acceptor layer relative the emitting polymer.
47
Favarim, Higor Rogerio. "Estudo dos processos fotofísicos em heteroestruturas orgânicas que utilizam chaveamento de luz por fotoalinhamento molecular." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-13092007-171145/.
Анотація:
O presente trabalho tem o objetivo de estudar os processos fotofísicos em filmes automontados de poli( -fenileno vinileno), ou PPV, sintetizados e processados no Grupo de Polímeros Prof. Bernhard Gross (GPBG) do IFSC, através dos processos de transferência de energia para o azocromóforo BY ou dentro da própria cadeia do PPV, através de um gradiente energético. O trabalho está focado no entendimento dos canais de relaxação energéticos, durante a difusão espectral, onde atuam o decaimento, radiativo e não radiativo. Pelo uso de uma engenharia molecular específica, propiciada pelo método de automontagem, heteroestruturas foram fabricadas para o estudo da transferência de energia (TEE) para azocromóforos, separados por uma camada separadora inerte. A novidade está no fato de podermos selecionar os estados do BY através da mudança do pH da solução, durante o processo de fabricação dos filmes. Com este sistema foi possível comprovar que os estados intermediários, durante a difusão espectral, desempenham um importante papel para a TEE, podendo transferir a excitação molecular para camadas adjacentes em heteroestruturas orgânicas. Este resultado, juntamente com a nova metodologia adotada para a conversão do PTHT em PPV, a adoção do íon de cadeia longa dodecilbenzenosulfônico (DBS), foi suficiente para desenvolvermos novas estruturas de TEE, possibilitando a modulação energética dos estados HOMO e LUMO dos polímeros conjugados. Este resultado comprova a TEE nos estágios iniciais da difusão espectral concomitantemente direcionar a excitação energética para regiões específicas das heteroestruturas, implicando em uma nova metodologia para o aumento da eficiência em dispositivos orgânicos luminescentes.The subject of this work is the study of the photophysics process in poly (p-phenylene vinylene) self-assembled films (PPV), with were synthesized and processed at the Grupo de Polímeros Prof. Bernhard Gross (GPBG) of the IF8C, by the energy transfer process (TEE) for, the azochromophore Brilliant Yellow (BY) or inside the PPV polymeric chain by an energetic gradient. We are interesting in the energetic relaxation pathway meaning, during the spectral diffusion, were the decay acts, radioactive and non-radioactive. By using a specific molecular engineering, propitiated by the self¬assembly method, heterostructures were done to study the energy transfer (TEE) to azochromophores, separated by an inert spacer. The novelty is on the ability of sort the BY states by changes on the pH solution, during the film fabrication process. With such system, we could prove that intermediary states, during spectral diffusion, played an important role for the TEE, and should been transfer to adjacent blocks. This result, with the new methodology adopted for the PTHT to PPV conversion, a long chain ion dodecylbenzenesulfonate (DBS), was enough to develop new structures for the TEE, build by a HOMO and LUMO energetic gradient states in conjugated polymers. These results verify the TEE in the initiate states of the spectral diffusion concomitance with the TEE for a specific film\'s region, implicating in a new methodology for an efficiency increase in organic luminescent devices.
48
Fernandes, Mauro Roberto. "\"Síntese e caracterização espectroscópica de materiais orgânicos para eletrônica molecular\"." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-13042007-171301/.
Анотація:
Este trabalho foi dividido em duas partes, sendo que na primeira (PARTE A) estão apresentadas as sínteses dos polímeros PPV, Cl-PPV, Br-PPV e dos co-polímeros (Cl-PPV)m / (PPV)n e (Br-PPV)m / (PPV)n nas seguintes relações m:n de 30:70; 50:50 e 70:30. Estes polímeros foram caracterizados por espectroscopia de infravermelho, UV-Visível e emissão de fluorescência. As modificações causadas nos polímeros, devido a dopagem com vapor de iodo e solução de cloreto férrico 0,12M em nitrometano também foram estudadas por estas mesmas técnicas. O acompanhamento da dopagem do PPV com vapor de iodo permitiu fazer a atribuição das bandas polarônicas e bipolarônicas por espectroscopia óptica. Também foram feitas medidas de voltametria cíclica que permitiram avaliar parâmetros eletrônicos importantes destes polímeros, tais como a Afinidade Eletrônica (HOMO), Potencial de Ionização (LUMO) e o GAP que é a diferença entre esses dois níveis de energia. Os co-polímeros apresentaram valores de energia do GAP menores que o PPV e níveis de energia de HOMO e de LUMO que podem ser apropriados para a utilização destes materiais em dispositivos eletroluminescentes (LED). Na PARTE B está apresentada a síntese de um composto inédito o 4- (2-fenoxi-p-xileno)-N-metil-1,8-naftalimida aqui chamado de NPOX. A caracterização do NPOX foi feita por espectroscopia de ressonância magnética v nuclear de próton (RMN 1H), espectrometria de massas (CG/MS), UV-Vis e Emissão de Fluorescência. O NPOX é solúvel em clorofórmio, que quando evaporado promove a formação de um filme transparente. Este filme tem emissão de fluorescência em 456 nm sendo excitado em 363 nm O filme também apresentou um comportamento semelhante a dos diodos demonstrado pela medida elétrica de corrente versus potencial (curva I x V). Estas propriedades abrem a possibilidade da utilização do NPOX como camada ativa, com emissão no azul, em OLED (Dispositivos Eletroluminescentes Orgânicos).This work was separated in two parts, in the first, called PART A, the synthesis of the polymers PPV, Cl-PPV, Br-PPV and of the co-polymers (Cl-PPV)m / (PPV)n and (Br-PPV)m / (PPV)n in the following relationships m:n of 30:70; 50:50 and 70:30 are presented. These polymers were characterized by infrared spectroscopy, UVvisible and fluorescence emission. The modifications caused in the polymers due to the doping with iodine vapor and 0,12M ferric chloride in nitrometano solution were studied also by these same techniques. The doping of PPV with iodine vapor have been monitored by optical spectroscopy allowing us to do the attribution of the polaronic and bipolaronic bands. Measurements of cyclic voltametry revealed important electric properties of these polymers, such as the Electronic Affinity (HOMO), Ionization Potential (LUMO) and \" GAP \" that is the difference between those two energy levels. The co-polymers presented smaller values of GAP than PPV and HOMO and of LUMO energy levels that can be appropriate to the use these materials in Light-Emitting Devices (LED). In PARTE B, the synthesis of an unpublished compound is presented, the 4-(2-fenoxi-p-xileno)-N-methyl-1,8-naftalimida, here called as NPOX. The characterization of NPOX was made by of nuclear magnetic resonance of proton vii spectroscopy (1H NMR), Gas Cromatography/ Mass Spectrometry (GC/MS), UVVisible and Fluorescence Emission spectroscopy. NPOX is soluble in chloroform that when evaporated it promotes in a transparent film formation. This film has fluorescence emission in 456 nm when excited in 363 nm. The film also showed a similar behavior as diodes that was demonstrated by the electric measurement of current versus potential (I x V curve). These properties open the possibility of the use of NPOX as activate layer, with emission in the blue region, in OLED (Organic Light- Emitting Devices).
49
Chen, Chiung-Yun, and 陳瓊筠. "Dilute Solutions Properties of MEH-PPV/THF and MEH-PPV/Toluene." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/97196687059510559788.
Анотація:
碩士元智大學
化學工程與材料科學學系
94
We investigated the molecular conformation of poly[1-methoxy-4- (2’-ethyl- hexyloxy)-2,5-phenylene vinylene] (MEH-PPV) in tetrahydrofuran (THF) and toluene solutions using dynamic light scattering (DLS) and static light scattering (SLS). Moreover the solutions were freeze dried and the molecular conformations of MEH-PPV were observed by Transmission Electron Microscopy (TEM). From the results of light scattering, the second virial coefficient (A2) in THF is slightly negative and in toluene is positive. It revealed that toluene is a better solvent for MEH-PPV than THF. The radius of gyration (Rg) and the weight average molecular weight (Mw) is larger in THF than in toluene, indicating the molecules aggregate in THF.
50
Qi, Dong Feng. "Photoluminescence from MEH-PPV and DP-PPV in bulk and encapsulated in porous alumina." Thesis, 2001. http://hdl.handle.net/2429/11797.
Анотація:
Two PPV derivatives, MEH-PPV and DP-PPV, are encapsulated in the nanopores of
anodized alumina with different pore sizes (50/200 nm) and depth (10/60 urn). Time-integrated
and time resolved optical emission properties of these structures have been studied and
compared with those of thin films of the polymers. Significant blue shifts of the PL spectra
(0.034 eV-0.183 eV) are found in the porous materials as compared to the bulk. The relative
intensity of the one-phonon assisted transition increases in comparison with the intensity of the
no-phonon transition in the nanostructured samples.
The time constants of the optical emission from the bulk MEH-PPV film are very
similar in their energy dependence to results obtained previously on bulk PPV films when
considered with respect to the excess energy above the peak of the emission spectrum. The
decay times are, however, two to three times shorter in the parent. The energy dependence of
the time constants measured in DP-PPV films and DP-PPV encapsulated in nanopores (pore
diameter 200 nm, pore depth 60 um) are also very similar to each other, and to the results
obtained on the MEH-PPV. These results suggest that the intrachain diffusion of electron-hole
excitations in all of these polymers, either in bulk or encapsulated form, is very similar.