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Functional analysis of Arabidopsis chromatin modification and remodeling regulators (CHR5 and JMJ15) in gene expression / Caractérisation fonctionnelle de deux régulateurs de la chromatine, CHR5 et JMJ15, chez Arabidopsis thalianaShen, Yuan 28 May 2014 (has links)
Le remodelage de la chromatine et la modification des histones jouent des rôles très importants dans l’établissement et la reprogrammation de l’état de l’expression génique. Il reste largement inconnu concernant les mécanismes de la régulation de ces processus chromatiniens dans le contrôle de l’expression génique impliquée dans le développement de la plante et son adaptation à l’environnement. Mon sujet de thèse se focalise sur l’analyse fonctionnelle d’un facteur de remodelage de la chromatine de type Chromodomain/Hélicase/DNA-binding 1 (CHD1) d’Arabidopsis, appelé CHR5 et une histone démethylase qui est spécifiquement impliquée dans la démethylation de l’histone H3 lysine 4 (H3K4), appelée JMJ15. Dans la première partie de cette étude, nous avons montré que le gène CHR5 est activé au cours de l’embryogénèse et que son expression se maintient élevé dans les tissues/organes en développement. L’analyse de mutants révèle que la perte de fonction de ce gène fait réprimer l’expression de gènes régulateurs de la maturation de l’embryon tels que LEC1, ABI3 et FUS3 pendant le développement des graines, et fait baisser l’accumulation des protéines de réserve. L’analyse de double mutants a permis de démontrer une fonction antagoniste entre CHR5 et PKL, une protéine du groupe « CHD3 », dans l’activité du promoteur de gènes régulateurs du développement de l’embryon et l’accumulation de réserve de graine. Nous avons montré que la protéine CHR5 s’associe directement avec les promoteurs d’ABI3 et FUS3 et que la mutation du gène CHR5 conduit à l’augmentation de présence de nucléosome dans la région du départ de transcription. Ces résultats suggèrent que CHR5 est impliquée dans le positionnement de nucléosome pour stimuler l’expression de gènes de la maturation de l’embryon, ce qui est contrebalancé par l’action de PKL au cours du développement de l’embryon. La deuxième partie de cette étude a permis de montrer que l’expression du gène de l’histone démethylase JMJ15 manifeste une forte spécificité tissulaire. L’analyse de mutants du gène a permis de l’identification de 2 allèles de gain de fonction (avec surexpression du gène), et un allèle de perte de fonction. La surexpression du gène réduit la croissance d’hypocotyle et de tige de la plante avec accumulation de lignine dans la tige, mais le perte de fonction du gène ne produise pas de phénotype apparent. Par ailleurs, la surexpression du gène renforce la tolérance de la plante au stress salin, alors la perte de fonction du gène rend la plante plus sensible. L’analyse du transcriptome a révélé beaucoup plus de gènes réprimés qu’activés par la surexpression du gène JMJ15. Ces gènes réprimés sont préférentiellement marqué la H3K4me2 ou H3K4me3, parmi lesquels beaucoup codent de facteurs de transcription. Ces données suggèrent que l’induction de JMJ15 pourrait réguler le programme de l’expression génique qui coordonne la restriction de la croissance de la plante et la tolérance au stress. Ces travaux de thèse a permis ‘identifier quelques nouveaux éléments dans la compréhension de la fonction de régulateurs chromatiniens dans l’expression génique de la plante. / Chromatin remodeling and histone modification play important roles in the establishment and dynamic regulation of gene expression states. However, little is known regarding to the regulatory mechanism of chromatin modification and remodeling that control gene expression involved in plant development and responses to environmental cues. My thesis work concerns functional analysis of an Arabidopsis Chromodomain/Helicase/DNA-binding 1 (CHD1) type chromatin remodeling gene known as CHR5 and a histone demethylase gene that specifically removes methyl groups from methylated histone H3 lysine 4 (H3K4me), called JMJ15 in regulating chromatin structure or in resetting chromatin modifications that control the expression of plant developmental and stress responsive genes. In the first part of the study we found that CHR5 expression is activated during embryogenesis and remained to be expressed in developing organs/tissues. Analysis of mutants revealed that loss-of-function of the genes led to decreased expression of key embryo maturation genes LEC1, ABI3 and FUS3 in developing seeds and reduced seed storage protein accumulation. Analysis of double mutants revealed an antagonistic function between CHR5 and PKL, a CHD3 gene, in embryo gene promoter activity and seed storage protein accumulation. CHR5 was directly associated with the promoters of ABI3 and FUS3 and chr5 mutations led to increased nucleosome occupancy near the transcriptional start site. The results suggest that CHR5 is involved in nucleosome occupancy to regulate embryo identity genes expression, which is counterbalanced by PKL during embryo development. The second part of this study showed that expression of JMJ15 was restricted to a few tissues during vegetative growth. The jmj15 gain-of-function mutations reduced the length of seedling hypocotyls and inflorescence stems with higher accumulation of lignin in the stem, while the loss-of-function mutants did not show any visible phenotype. The gain-of-function mutants enhanced salt tolerance, whereas the loss-of-function mutants were more sensitive to salt. Transcriptomic analysis revealed a much higher number of genes down-regulated in JMJ15 over-expression plants, which are highly enriched for H3K4me3 and H3K4me2. Among the down-regulated genes, many encode transcription regulators of stress responsive genes. The data suggest that increased JMJ15 levels may regulate the gene expression program that may coordinate plant growth restrains and enhances stress tolerance. Taken together, my thesis work brought a few new elements to the current understanding of chromatin regulators function in plant gene expression.
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Policy approaches to prevent chronic non-communicable diseases: The role of population-based dataNojilana, Beatrice January 2018 (has links)
Philosophiae Doctor - PhD / Background: Non-communicable diseases (NCDs) continue to rise in South Africa, accounting for 43% of total deaths in 2012. Smoking and a diet high in salt are among the major modifiable risk factors for NCDs that can be addressed through cost-effective policy interventions in the form of regulation or legislation and active multisectoral engagement. Population-based prevalence and mortality data are necessary for monitoring and evaluation such interventions. South Africa has developed a National Strategic Plan for NCDs but there is limited evaluation of NCD policies. Furthermore, there is a need to explore the availability of population-based data and the role that it can play to monitor interventions.
Aim: The overall aim of the thesis is to assess the implementation of policies for reducing risk factors for chronic NCDs in South Africa, and to explore the role of population-based data in supporting environmental and policy approaches to prevent NCDs. The thesis will also examine whether there are differences in urban and rural settings in the implementation of tobacco control and salt reduction regulation as well as the barriers to implement the National Strategic Plan for prevention of NCDs.
Methods: Multiple methods of data collection were used. A desk review of policies to address NCDs in South Africa was undertaken and semi-structured interviews with the NCD policymakers and managers in two provinces (the Eastern Cape and Western Cape) were undertaken, to explore challenges and successes of implementation of the NSP. The Cross-sectional baseline questionnaire and quantified food frequency data from the PURE study were used to determine the prevalence of smoking and the intakes of sodium and potassium in a selected urban and a rural community. Data collected using a validated community audit tool was used to assess the physical environment related to tobacco as well as questionnaire data from face-to-face interviews about perceptions about tobacco use in the urban and rural communities. Trends in mortality from tobacco related and high salt consumption related conditions together with prevalence data from national health surveys were reviewed to assess the health impact.
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[en] CONSTITUTIVE MODELING AND PROBABILISTIC ANALYSIS APPLIED TO WELLS IN SALT ZONES / [pt] MODELAGEM CONSTITUTIVA E ANÁLISE PROBABILÍSTICA APLICADAS A POÇOS EM ZONAS DE SALPEDRO ALCIDES LOBO PENNA FIRME 22 January 2015 (has links)
[pt] A perfuração de camadas espessas de sal para exploração do pré-sal brasileiro desafia a geomecânica no aprimoramento da modelagem computacional dessas rochas. Previsões acuradas podem evitar problemas operacionais na perfuração, desde a necessidade excessiva de repasses até a prisão da coluna de perfuração, ou mesmo a perda do poço. O comportamento mecânico das rochas salinas é diferente daquele geralmente descrito pela mecânica das rochas tradicional. A compreensão do fenômeno da fluência constitui um embasamento conceitual indispensável para simulações numéricas nessas rochas. Foram apresentadas metodologias para simulação do comportamento à fluência de rochas salinas adotando o programa comercial de elementos finitos ABAQUS. Três modelos constitutivos para fluência baseados em leis de potência foram testados em simulações de ensaios triaxiais de fluência, galeria de mineração e poços revestidos e não revestidos. Destaca-se o primeiro esforço no intuito de calibrar e validar o Modelo de Multi Mecanismo de Deformação para aplicação em halita brasileira. Além disso, é apresentada uma metodologia para análises probabilísticas de fechamento de poço e de plastificação de revestimento. O programa NESSUS foi adotado e métodos de confiabilidade de Valor Médio foram empregados. Um modelo transversal de poço revestido típico do cenário do pré-sal brasileiro é considerado. Para ambos os eventos e modelos constitutivos, resultados determinísticos estão associados à probabilidade de falha de 40 por cento. As variáveis de maior importância nas análises de fluência em rochas salinas são aquelas relacionadas ao estado de tensão, temperatura e a fluência secundária. Por fim, ressalta-se o excelente desempenho do Modelo de Multi Mecanismo de Deformação nas simulações numéricas realizadas nesta pesquisa. / [en] Drilling thick salt rock layers for Brazilian pre-salt exploitation challenges geomechanics in improving computational modeling of those rocks. Accurate predictions can avoid operational complications in the drilling job, ranging from the excessive necessity of new drillings to a stuck pipe or even the loss of the wellbore. Salt rock shows unique properties. The mechanical behavior of salt rock is different from that usually described in traditional rock mechanics. The understanding of the creep phenomenon constitutes an indispensable conceptual background for numerical simulation of salt rocks. Some methodologies are presented for the simulation of salt rock creep behavior using the commercial finite element code ABAQUS. Three power-law-based constitutive models for creep are tested on simulations of triaxial creep tests, a mining gallery and both cased and uncased wellbores. A first effort to calibrate and validate the Multi-mechanism Deformation Creep Model for application in the Brazilian halite should be highlighted. Moreover, a methodology for probabilistic analyses of wellbore closure and casing yielding is presented. The software NESSUS is adopted and the Mean Value reliability methods are employed. A transversal model of cased wellbore typical for a Brazilian pre-salt scenario is considered. For both events and constitutive models, deterministic results are associated to a probability of failure of 40 per cent. Variables with the highest importance in salt rock creep analyses are related to the stress state, temperature and steady-state creep. Finally, the excellent performance of the Multi-mechanism Deformation Creep Model in the numerical simulations carried out in this research is noteworthy.
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An Investigation of Bent-Beam Stress-Corrosion Test for Titanium AlloysLeón Zapata, Daniel January 2019 (has links)
Titanium alloys are highly resistant to all types of corrosion due to their excellent ability to form an oxide film on the surface. However, under certain circumstances, these alloys may experience an environmental degradation which could potentially, under the application of mechanical stress, lead to a complete failure of the material. One of these cracking processes is stress-corrosion cracking (SCC). SCC has an embrittling effect on otherwise ductile materials under tensile stress. Since titanium alloys are frequently used in the aerospace industry and it is therefore of interest to test these alloys in different environment in order to prevent any future accidents. SCC testing is frequently tested at GKN Aerospace and a new testing method is of interest. The main objective with this work was to gain knowledge of the testing method. Bent-beam testing method has been used to investigate stress-corrosion cracking (SCC) of titanium alloys in a laboratory based experiment. The bent-beam testing method was of type 2-point bent beam test, where a saline solution was applied at the apex of the specimen. The specimens were loaded to a range of stresses from 40%, to 95% of the materials yield strength and the salt concentration in the saline solution was 1wt% and 3wt%. By doing so, a relative susceptibility of the different alloys could be established. Three different titanium alloys were tested: Ti-6Al-4V, Ti-8Al-1Mo-1V, and Ti-6Al-2Sn-4Zr-2Mo. The testing method was able to cause cracking on all titanium alloys, where Ti-6Al-4V was found to be the least susceptible to SCC. Ti-8Al-1Mo-1V, and Ti-6Al-2Sn-4Zr-2Mo showed an overall high susceptibility to SCC as cracking occurred in all testing configurations. Cracking was observed on both the surface of the specimen as well as in the cross sections, where the cracks grew perpendicular to the surface. SEM was also used to evaluate the crack propagation in Ti-8Al-1Mo-1V, and Ti-6Al-2Sn-4Zr-2Mo, and it was found that the cracks grew mostly along the grain boundaries.
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Statistical Assessment of Hydrochemical Characteristics of Streams and Rivers in Eastern New EnglandXian, Qing January 2009 (has links)
Thesis advisor: Rudolph Hon / This study characterizes the current state of water quality of surface streams and rivers in the eastern New England region. A set of water quality data for nine rivers, part of the USGS National Water-Quality Assessment (NAWQA) Program was statistically evaluated to identify natural and anthropogenic persistent influential factors on water quality in surface waters. Binary analysis and multivariate analysis, mainly Principal Component Analysis (PCA) and Factor Analysis (FA) were applied to determine the least number of independent relationships among multiple chemical components in the data set. Statistical results show that in eight of the nine rivers included in this study, four principal components can explain about 80% of the total variance of the original data. The most significant contributing factors can be identified with: (1) chemical weathering; (2) road salt applications; (3) nutrient cycling; and (4) agricultural/waste water. / Thesis (MS) — Boston College, 2009. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Geology and Geophysics.
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Norepinephrine-evoked renal regulation of sodium homeostasis in salt-sensitive hypertensionWalsh, Kathryn 15 June 2016 (has links)
Hypertension affects 1 in 3 adults and is the single greatest risk factor for premature death. Salt-sensitive hypertension occurs in approximately 50% of hypertensive patients and results in a 3-fold increase in the risk of adverse cardiovascular events. However, the pathophysiology of salt-sensitive hypertension remains to be fully elucidated. There has been increased interest in the interaction between the sympathetic nervous system and the kidney and how that interaction mediates sodium excretion to drive the development of salt-sensitivity. Previous studies show that sympathetic over-activity increases expression of the sodium chloride cotransporter (NCC) resulting in increased NCC-mediated sodium reabsorption, and the development of salt-sensitive hypertension. In this thesis, I show the effect of increased norepinephrine (NE) and high salt intake in salt-resistant vs. salt-sensitive rat phenotypes on blood pressure regulation, NCC activity, and the adrenoreceptor-mediated regulatory kinase network signal transduction pathway. A high salt diet 1) exacerbates NE-induced hypertension in salt-resistant Sprague-Dawley (SD) rats and 2) results in hypertension in Dahl salt-sensitive (DSS) rats. In contrast to salt-resistant phenotypes (SD & Dahl salt-resistant), dietary sodium-evoked suppression of NCC expression and activity is prevented in salt-sensitive rats (SD-NE infusion & DSS) - I show that this occurs through a failure of a high salt intake to suppress renal OxSR1, SPAK, and WNK1 (NCC regulatory proteins). I demonstrate that α1-adrenoreceptors are responsible for mediating the salt-sensitive component of hypertension and restore dietary sodium-evoked suppression of the NCC via a predominant OxSR1 pathway. Chronic β-adrenoreceptor antagonism significantly reduces blood pressure in NE-mediated hypertension. How the body senses salt remains unknown, but my data show that selective removal of the afferent renal nerves prevents dietary sodium-evoked suppression of NCC expression and activity resulting in salt-sensitive hypertension, suggesting that the afferent renal nerves play an important role as a sodium-sensing mechanism. Overall, these data demonstrate that attenuated afferent renal nerve feedback drives renal efferent nerve release of NE to prevent the downregulation of the NCC via an α1-adrenergic receptor-gated WNK1-OxSR1 signal transduction pathway to evoke the development of salt-sensitive hypertension.
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O caminhar nas paisagens de sal /Oliveira, Sérgio Augusto de. January 2019 (has links)
Orientador: José Paiani Spaniol / Resumo: Esta pesquisa apresenta um estudo empírico sobre a presença do sal na constituição de paisagens que exibem tal matéria como um dos elementos de sua formação. As Paisagens de Sal escolhidas nesta pesquisa foram as salinas de Araruama, no Rio de Janeiro, Brasil; o Deserto de Atacama, no Chile; e o Salar de Uyuni, na Bolívia. Através de residências artísticas realizadas nestes locais, se pretende o registro de imagens e vídeos, coleta de objetos e entrevistas que revelem as características visuais, históricas e culturais que o sal impõe a estas paisagens, bem como as especificidades cromáticas, materiais e naturais exibidas em cada uma das localidades. Como resultado das reflexões e da experiência vivenciada nas residências, também se pretende a produção de ações artísticas nas Paisagens de Sal, derivadas dos dados e impressões colhidos durante a pesquisa. / Abstract: This research aims to present a study on the presence of salt in the constitution of landscapes that exhibit such matter as a landscape forming element. The Salt Landscapes chosen in this research were the Araruama salt salines, in Rio de Janeiro, Brazil; the Atacama Desert in Chile; and the Salar de Uyuni, in Bolivia. Through artistic residences in these places, the aim was to collect images, photographs, videos, interviews that reveal the visual, historical and cultural characteristics that the salt imposes on the landscapes, as well as the specific conditions in each one of the localities. Artistic actions are also foreseen in the Salt Landscapes as a result and reflection of the data collected in the research. / Doutor
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Fosfito de potássio no controle de doenças pós-colheita em bagas de uva ´Itália´ e possíveis mecanismos de ação à Rhizopus stolonifer / Potassium phosphite on postharvest disease control in ´Itália´ grape berries and possible mode of action to Rhizopus stoloniferRoma, Rafaela Carolina Constantino 10 March 2014 (has links)
A ocorrência de doenças em uvas de mesa gera perdas desde o cultivo até a comercialização, o que afeta diretamente o potencial de exportação do Brasil. A prevenção na realização de injúrias nos frutos é essencial para garantir a eficácia dos tratamentos aplicados tanto em pré- quanto em pós-colheita. Visando o emprego de produtos alternativos que auxiliem no manejo sustentável da cultura, o fosfito de potássio encontra-se como ferramenta útil. O efeito do fosfito no controle de doenças causadas por oomicetos já foi relatado, porém, como este ingrediente ativo atua sobre microrganismos do reino Fungi ainda é desconhecido. Neste contexto, este trabalho teve como objetivo avaliar o fosfito de potássio no controle das doenças podridão mole, mofo cinzento e podridão da uva madura, causadas por Rhizopus stolonifer, Botrytis cinerea e Colletotrichum gloeosporioides, respectivamente, em bagas de uva ´Itália´ e seus efeitos na qualidade físico-química dos frutos. Também objetivou-se estudar os mecanismos de ação envolvidos na inibição do desenvolvimento do micélio de R. stolonifer na presença do produto e na indução de respostas de defesa em bagas de uva. Foram realizados ensaios in vitro para avaliação do efeito do fosfito sobre o crescimento micelial, esporulação e germinação dos esporos para R. stolonifer, B. cinerea e C. gloeosporioides. Experimentos utilizando-se de bagas foram conduzidos, visando avaliar o efeito no uso do fosfito como fungicida produtor ou curativo para os três patógenos. Cachos foram utilizados para se determinar os efeitos da aspersão do fosfito sobre a qualidade físico-química dos frutos. Para avaliação dos mecanismos de ação do fosfito sobre o micélio de R. stolonifer, foram determinados os efeitos sobre a permeabilidade da membrana plasmática, a síntese de parede celular e a síntese de proteínas. A atividade de guaiacol peroxidase e de compostos fenólicos totais foi determinada em bagas de uva tratadas ou não com fosfito. Houve inibição do crescimento micelial, da esporulação e da germinação dos esporos dos patógenos desenvolvidos em diferentes concentrações de fosfito de potássio. O tratamento protetor e curativo das bagas evidenciou reduções significativas na área abaixo da curva de progresso das doenças estudadas. Não houve efeito do produto sobre a qualidade físico-química dos cachos de uva. Quanto aos mecanismos de ação, foram observados efeitos do fosfito sobre a permeabilidade de membrana, devido à elevada perda de eletrólitos do micélio. O fosfito proporcionou elevação na síntese de proteínas totais no micélio do patógeno e redução na atividade de ?-1,3- glucanase e quitinase, que são enzimas relacionadas à síntese de parede. A atividade de guaiacol peroxidase e a concentração de compostos fenólicos totais não aumentou com a aplicação do fosfito nas bagas. Desta forma, pode-se concluir que o fosfito de potássio controlou a podridão mole, o mofo cinzento e a podridão da uva madura e não teve efeito sobre a qualidade físico-química dos frutos. Ainda, o fosfito atuou sobre a permeabilidade de membrana, síntese de proteínas e de parede celular do micélio de R. stolonifer e não proporcionou indução da atividade de guaiacol peroxidase e compostos fenólicos totais em bagas de uva. / The occurrence of table grape diseases causes losses from the field to the commercialization, which affects the Brazil potential to export. The prevention of injuries in fruits is essential to ensure the pre- and postharvest treatment efficiency. In order to use alternative products to support the crop sustainable management, phosphite may be a useful tool. The phosphite effect on control of diseases caused by oomycetes has been reported, however, how the active ingredient acts on microorganisms from the Fungi kingdom is unknown. Thus, the objective was to evaluate potassium phosphite on the control of soft rot, grey mold and ripe rot, caused by Rhizopus stolonifer, Botrytis cinerea e Colletotrichum gloeosporioides, respectively, in ´Itália´ grape berries and its effect on physico-chemical properties of the fruits. Moreover, the objective was to study the mode of action involved on the inhibition of R. stolonifer grown in the presence of phosphite and on the induction of defense responses in grape berries. In vitro assays were carried out to evaluate the effect of phosphite on mycelial growth, sporulation and spore germination in R. stolonifer, B. cinerea e C. gloeosporioides. Single berries were used in order to evaluate the effect of phosphite as a protective or curative fungicide against the three pathogens. Grape clusters were used to determine the effects of phosphite spraying on physico-chemical properties. To evaluate the mode of action of phosphite on R. stolonifer mycelium the plasma membrane permeability, the protein synthesis and the cell wall synthesis were monitored. The guaiacol peroxidase activity and phenolic compound concentration were evaluated in grape berries treated or not with phosphite. There were inhibition on mycelial growth, sporulation and spore germination on the three pathogens in different potassium phosphite concentrations. The protective and curative treatment in grape berries showed significant reductions on the area under disease progress curve of the studied diseases. There was no effect on physico-chemical properties of the grapes. Regarding the mode of action, the phosphite affected membrane permeability what was seen as high electrolyte leakage from the mycelium. Phosphite caused high protein synthesis in the mycelium and reduction on ?-1,3-glucanase and chitinase activities, which are enzymes related to cell wall synthesis. The guaiacol peroxidase activity and phenolic compound concentration did not increase due the phosphite application. Thus, it may be concluded that potassium phosphite controlled soft rot, grey mold and ripe rot in grape berries and did not affect the physico-chemical properties of the fruits. Besides that, phosphite still acted on membrane permeability, protein synthesis and cell wall synthesis on the R. stolonifer mycelium and did not changes in guaiacol peroxidase activity and phenolic compound concentration in the grape berries.
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Qualidade do bacalhau salgado seco comercializado em temperatura ambiente e refrigerado / Quality of dried salt cod commercialized at ambient temperature and refrigeratedBaltazar, Camila 06 July 2012 (has links)
O comércio varejista brasileiro expõe o bacalhau salgado seco inteiro ou porcionado sem refrigeração. Esta condição, tradicionalmente aceita pelos consumidores, contraria as especificações do fabricante de manter o produto sob refrigeração, o que frequentemente gera conflitos entre as autoridades sanitárias e o comércio. Perante este fato, o presente estudo avaliou parâmetros microbiológicos e físico-químicos de 56 amostras de bacalhau obtidas no município de São Paulo, armazenadas sob refrigeração (0 a 5ºC) e em temperatura ambiente (20ºC a 25ºC), nos tempos zero, sete e 14 dias de armazenamento. As amostras foram agrupadas em 4 categorias: A-amostras refrigeradas não manipuladas e B, C e D manipuladas, respectivamente, com zero, 7 e 14 dias de armazenamento em temperatura ambiente. A temperatura ambiente variou de 20,5 a 23,5ºC e a umidade relativa do ar de 52,5 a 67%. Pesquisaram-se: Staphylococcus coagulase positiva, Clostridium sulfito redutores, coliformes totais e termotolerantes, Salmonella spp, bolores, leveduras e bactérias halofílicas. As análises físico-químicas realizadas foram: umidade, pH, atividade de água (Aa) e resíduo mineral fixo. Não houve diferenças nos resultados obtidos entre as 4 categorias e estes apresentaram-se dentro dos limites estabelecidos pela legislação brasileira. Com relação às análises físico-químicas também não houve diferença estatística entre as 4 categorias. Os valores médios obtidos, por categoria, foram: A: 54,9% de umidade; Aa=0,748; pH=6.0; B: 54,0% de umidade; Aa=0,749; pH=6.0; C: 49,1% de umidade; Aa=0,749; pH=6.0 e para a categoria D: 50,7% de umidade; Aa=0,748; pH=6.0 e 21,6% de resíduo mineral fixo. Todos os valores de umidade encontrados estavam acima do padrão (45%); os valores de pH obtidos estavam de acordo com o padrão (6 a 7) e os valores de resíduo mineral fixo contemplaram a legislação vigente (mín. 10%). Com relação à Aa, os valores sugerem que esta é uma importante barreira para o desenvolvimento microbiano e, embora não haja padrão para este parâmetro, julga-se necessário determinar um valor referência como limite máximo. Conclui-se que, nas condições do presente estudo, o comércio do bacalhau salgado seco mantido sob refrigeração ou em temperatura ambiente por 14 dias oferece as mesmas condições de segurança sanitária para o consumidor. / The Brazilian retail exposes the dried salt cod, whole or portioned without refrigeration. This condition is traditionally accepted by consumers, contrary to the manufacturer specifications to keep the product refrigerated, which often create conflicts between health authorities and traders. Given this fact, this study evaluated microbiological parameters and physico-chemical properties of 56 samples of cod collected in São Paulo, stored refrigerated (0-5 ° C) and ambient temperature (20 ° C to 25 ° C), for zero, seven and 14 storage days. The samples were grouped into four categories: A-refrigerated samples unmanipulated and B, C and D manipulated, respectively, zero, 7 and 14 days of storage at ambient temperature. The temperature ranged from 20.5 to 23.5 ° C and relative humidity from 52.5 to 67%. The following investigations were conducted: coagulase positive Staphylococcus, Clostridium sulfite reducer, total and fecal coliforms, Salmonella spp, molds, yeasts and bacteria halophilic. The following physic chemical analyzes were carried out: moisture, pH, water activity (Aw) and ash. The results presented no differences between the four categories and respected the limits established by Brazilian legislation. With respect to physical and chemical analyzes, they also showed no statistical differences among the four categories. The average results for each category were: A: 54.9% moisture, Aa = 0.748, pH = 6.0, B: 54.0% moisture, Aa = 0.749, pH = 6.0, C: 49.1% moisture, Aa = 0.749, pH = 6.0 and for D: 50.7% moisture, Aa = 0.748, pH = 6.0 and 21.6% of ash. All results had higher humidity values compared to the standard threshold (45%), pH results were obtained in accordance with the pattern limits (6-7) and the ash results contemplated the legislation limit (min. 10%). With respect to Aa, the figures suggest that this is an important barrier to microbial growth and, although there is no standard limits for this parameter, it is necessary to determine a reference threshold for this parameter. We conclude that, under the conditions of the present study, the trade of dried salt cod kept refrigerated or at ambient temperature for 14 days offer the same health and safety conditions for the consumer.
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Avaliação microestrutural e mecânica da Incoloy® 945 após tratamentos térmicos / Microstructural and mechanical evaluation of Incoloy® 945 after heats treatmentMartins, Igor Colado Porto 18 September 2015 (has links)
Superligas de níquel são materiais mundialmente empregados nas áreas de petróleo e gás natural, aeroespacial e nuclear. A Incoloy® 945 uma liga desenvolvida em meados dos anos 2000, para ser uma liga hibrida entre a Inconel® 718 e Incoloy® 925, concebendo uma liga com propriedades mecânicas e anticorrosivas capaz de suportar as mais adversas operações de serviço. Neste trabalho foram determinadas algumas características mecânicas do material, após laminação a frio, seguindo duas diferentes rotas de tratamento térmico. Foram realizados testes de dureza Vickers e tração, onde mostrou que a rota experimental criada no IPEN (por intermédio da análise por calorimetria exploratória diferencial), tem a mesma resistência mecânica do que a rota comercialmente usada, contudo possui uma maior ductilidade. O material demonstra uma excepcional união resistência mecânica e ductilidade, podendo ser empregada no uso de tubulações e válvulas de alta complexidade de manufatura, para a exploração das camadas do pré-sal. / Nickel super alloy materials are used worldwide in the areas of oil and gas, aerospace and nuclear. The Incoloy® 945 an alloy developed in the mid-2000s, to be a hybrid alloy between the Inconel® 718 and Incoloy® 925 by designing an alloy with mechanical and anti-corrosion properties able to withstand the most adverse service operations. In this work we were determined some mechanical characteristics of the material after cold rolling, following two different routes of heat treatment. Hardness Vickers tests and traction test were conducted, which showed that the experimental route created at IPEN (through analysis by differential scanning calorimetry), has the same mechanical strength than the route used commercially, it nevertheless has a higher ductility. The material shows an exceptional union strength and ductility and can be used in the use of pipes and high complexity manufacturing valves for the operation of the pre-salt layers.
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