1000 resultados para Via esteroidogênica


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O herbicida Atrazina (ATR) é um agrotóxico utilizado há cerca de 50 anos, responsável pelo controle seletivo de plantas daninhas em cultivo de arroz, milho e cana-de-açúcar, principalmente. Estudos recentes apontam diversos efeitos desse herbicida em invertebrados e vertebrados, através da contaminação do solo, bem como da lixiviação para os ecossistemas aquáticos. Foi demonstrado que a ATR é um desregulador endócrino, além de causar efeitos como estresse oxidativo, imunotoxicidade e distúrbios no metabolismo energético. No presente estudo, a espécie nativa Poecilia vivipara foi utilizada como modelo experimental para identificar e analisar a expressão de genes atuantes na via esteroidogênica (StAR e Cyp19a1) e genes atuantes no sistema de defesa antioxidante enzimático (SOD-1 e CAT), frente a exposição à diferentes concentrações de ATR. Sequências parciais dos genes-alvo foram obtidas e comparadas com sequências disponíveis de espécies próximas. Foram analisadas a expressão órgãoespecífica para cada um dos genes isolados, bem como a expressão dos genes frente à exposição ao herbicida atrazina. Os animais foram expostos a ATR em concentrações de 2, 10 e 100 µg/L e a expressão dos genes em gônadas e fígado desses animais foram analisadas em 24 e 96 horas de exposição. As sequências obtidas dos genes StAR, Cyp19a1, SOD-1 e CAT apresentaram 821, 80, 954, 350 pares de bases respectivamente, com identidades que variam de 86 a 100% com espécies filogeneticamente próximas a P. vivipara. Os animais apresentaram uma maior expressão dos genes StAR e Cyp19a1 nas gônadas e no fígado, enquanto a menor expressão se mostrou em órgãos como intestino e baço. Já os genes SOD e CAT apresentaram uma maior expressão no fígado, e menor expressão no intestino. Em relação à expressão gênica frente à exposição à ATR, os resultados apontaram para uma indução dos genes StAR, SOD e CAT em 24 horas, nas gônadas e no fígado, enquanto 8 que a expressão do gene Cyp19a1 foi aumentada apenas após 96 horas de exposição. Foi demonstrado que o herbicida ATR, mesmo em baixas concentrações, é capaz de desregular a expressão de genes que codificam tanto para proteínas componentes da via de síntese de hormônios esteróides, quanto para enzimas atuantes na resposta antioxidante celular de P. vivipara. 

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The synthesis of a new structural class of isoindoline nitroxides (aminoxyls), accessible via the palladium-catalysed Heck reaction, is presented. Reaction of the aryl bromoamine, 5-bromo-1,1,3,3-tetramethylisoindoline (4) or dibromoamine, 5,6-dibromo-1,1,3,3-tetramethylisoindoline (5) or the analogous bromonitroxides 6 and 7 with methyl acrylate gives the acrylate substituted tetramethylisoindoline amines 8 and 10 and nitroxides 12 and 14. Similarly, the reaction of the aryl bromides and dibromides 4–7 with methyl 4-vinylbenzoate gives the carboxystyryl substituted tetramethylisoindoline amines 9 and 11 and the analogous nitroxides 13 and 15. The carboxystyryl tetramethylisoindoline nitroxides demonstrate strongly suppressed fluorescence, which is revealed upon removal of the free radical by reduction or radical coupling.

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Among the many promises of the digital revolution is its potential to strengthen social equality and make governments more responsive to the needs of their citizens. E-government is the use of information and communications technologies (ICTs) to transform governments by making them more accessible, effective, accountable, and making the most of the new technologies to deliver better quality and more accessible public services. This paper provides an overview of recent literature addressing e-government issues, and includes a discussion of its implications at the municipal level. It also covers Australian experiences in establishing and managing e-government services.

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Energy efficient lubricants are becoming increasingly popular. This is due to a global increase in environmental awareness combined with the potential of reducing operating costs. A new test method of evaluating the energy efficiency of gear oils has been described in this report. The method involves measuring the power required by an FZG test rig to run while using a particular test lubricant. For each oil that was being evaluated, the rig was run for 10 minutes at a load stage of 10. Six extreme pressure (EP) industrial gear oils of mineral base were tested. The difference in power requirements between the best and the worst performing oils was 2.77 and 3.24 kW, respectively. This equates to a 14.6% reduction in power, a significant amount if considered in relation to a high powered industrial machine. The oils of superior performance were noticed to run at reduced temperatures. They were also more expensive than the other products of lesser performance.

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Efforts to improve mathematics and science content knowledge have in many institutions required redefining teacher education through new teaching and learning. See, for example, Peard & Pumadevi (2007) for an account of one such attempt involving the development of a Foundations Unit, Scientific and Quantitative Literacy. This unit is core for all first year pre-service primary teacher education students at Queensland University of Technology (QUT) and two Education Institutes in Malaysia, Institute Perguruan Raja Melewar (IPRM), and Institute Perguruan Teknik (IPT) Kuala Lumpur. Since then, QUT has modified the unit to adopt a thematic approach to the same content. An aim of the unit rewrite was the development of a positive attitude and disposition to the teaching and learning of mathematics and science, with a curiosity and willingness to speculate about and explore the world. Numeracy was specifically identified within the mathematics encountered and appropriately embedded in the science learning area. The importance of the ability to engage in communication of and about mathematics and science was considered crucial to the development of pre-service primary teachers. Cognisance was given to the appropriate selection and use of technology to enhance learning - digital technologies were embedded in the teaching, learning and assessment of the unit to avoid being considered as an optional extra. This was achieved around the theme of “the sustainable school”. This „sustainability‟ theme was selected due to its prominence in Australia‟s futures-oriented National Curriculum which will be implemented in 2011. This paper outlines the approach taken to the implementation of the unit and discusses early indicators of its effectiveness.

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Efforts to improve mathematics and science content knowledge have in many institutions required redefining teacher education through new teaching and learning. See, for example, Peard & Pumadevi (2007) for an account of one such attempt involving the development of a Foundations Unit, Scientific and Quantitative Literacy. This unit is core for all first year pre-service primary teacher education students at Queensland University of Technology (QUT) and two Education Institutes in Malaysia, Institute Perguruan Raja Melewar (IPRM), and Institute Perguruan Teknik (IPT) Kuala Lumpur. Since then, QUT has modified the unit to adopt a thematic approach to the same content. An aim of the unit rewrite was the development of a positive attitude and disposition to the teaching and learning of mathematics and science, with a curiosity and willingness to speculate about and explore the world. Numeracy was specifically identified within the mathematics encountered and appropriately embedded in the science learning area. The importance of the ability to engage in communication of and about mathematics and science was considered crucial to the development of pre-service primary teachers. Cognisance was given to the appropriate selection and use of technology to enhance learning - digital technologies were embedded in the teaching, learning and assessment of the unit to avoid being considered as an optional extra. This was achieved around the theme of “the sustainable school”. This ‘sustainability’ theme was selected due to its prominence in Australia’s futures-oriented National Curriculum which will be implemented in 2011. This paper outlines the approach taken to the implementation of the unit and discusses early indicators of its effectiveness.

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This research applies an archaeological lens to an inner-city master planned development in order to investigate the tension between the design of space and the use of space. The chosen case study for this thesis is Kelvin Grove Urban Village (KGUV), located in inner city Brisbane, Australia. The site of this urban village has strong links to the past. KGUV draws on both the history of the place in particular along with more general mythologies of village life in its design and subsequent marketing approaches. The design and marketing approach depends upon notions of an imagined past where life in a place shaped like a traditional village was better and more socially sustainable than modern urban spaces. The appropriation of this urban village concept has been criticised as a shallow marketing ploy. The translation and applicability of the urban village model across time and space is therefore contentious. KGUV was considered both in terms of its design and marketing and in terms of a reading of the actual use of this master planned place. Central to this analysis is the figure of the boundary and related themes of social heterogeneity, inclusion and exclusion. The refraction of history in the site is also an important theme. An interpretive archaeological approach was used overall as a novel method to derive this analysis.