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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Synergism between N-heterocyclic carbene and phosphorus-based ligands in ruthenium and palladium catalytic systems

Schmid, Thibault E. January 2012 (has links)
N-heterocyclic carbenes (NHCs) have become a very popular class of ligands, which has found uses in numerous catalytic applications. The use of such compounds in combination with phosphorus-based ligands within metal complexes has enabled the design of very active yet robust catalytic systems. The following chapters will describe the design of novel well-defined palladium- and ruthenium-based pre-catalysts featuring a NHC and a phosphorus-based ligand, referred at as mixed ligand systems. Such species were employed in catalysis where their properties appeared highly beneficial, uses at low catalysts loading and under harsh conditions were then envisioned. The preparation of a series of well-defined palladium mixed NHC/phosphine species is presented in chapter 2. Their catalytic activity in the aqueous Suzuki-Miyaura reaction of aryl chlorides and boronic acids, using low catalyst loadings, is described. The observation of catalytic activity of the latter systems in the hydration of nitriles prompted us to further investigate this reactivity. This reaction appeared to be operative in the absence of palladium species and could be performed under base-catalysed conditions, which was studied in detail and depicted in chapter 3. The combination of a NHC and a phosphite ligand in ruthenium olefin metathesis pre-catalysts has been underexplored. Preliminary results showed that such species could be readily prepared and presented an unusual geometry and a high catalytic activity. Variations in phosphite-containing ruthenium olefin metathesis pre-catalysts are presented. Chapter 4 describes the investigation of various Schrock carbene moieties in such architectures, as well as their implications in structure and catalysis. Chapter 5 depicts attempts to design olefin metathesis Z-selective pre-catalysts by inserting a chelating NHC moiety within phosphite-containing ruthenium species. This dissertation concludes on the potential of such mixed species in catalysis, and armed with the new knowledge provided by this work, proposes potential developments of such chemistry in the design of always more robust and active catalytic systems.
112

Interação trófica entre Podisus nigrispinus e Supputius cincticeps (Heteroptera: Pentatomidae) / Trophic interaction between Podisus nigrispinus and Supputius cincticeps (Heteroptera: Pentatomidae)

Jacques, Gabriel de Castro 29 July 2011 (has links)
Made available in DSpace on 2015-03-26T13:30:33Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1105883 bytes, checksum: a8693b1ab79fc07546f743be5cf8c49a (MD5) Previous issue date: 2011-07-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Prey may be more or less consumed by control biologic agents and presents three kinds of interspecific interactions, (1) synergism, increase of mortality of prey comparing to each natural enemy independently, when the foraging of one species facilitates the capture of pest by another natural enemies. (2) Total mortality of the pest to natural enemies equals to the sum of individual mortality by each natural enemy. This occurs on independent natural enemies, when they prey different phases of pest’s life or in different temporal moments. (3) The total mortality of the pest by predator is lower than the individual sum for each predator. The decrease of predation tax may occur by different mechanisms, including the intraguild predation and the interespecific competition. Podisus nigrispinus (Dallas) and Supputius cincticeps (Stål) (Heteroptera: Pentatomidae), generalists predators of Neotropical region of South America, consume and share high variety of prey, not being restricted to inferior trophic level, because many may prey each other, on intraguild predation and on cannibalism. The aim of this work was determinate if there is competition and intraguild predation between P. nigrispinus and S. cincticeps. Besides that, study the effect of these phenomena on biology of the natural enemies and contribute to the understanding of interaction between predators on biologic control. On chapter I, the experiment was realized with adult females of this bugs and pupae of Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae) during nine days, when we analyzed the effect of intra and interespecific interactions on alimentary consume and on predation tax and the occurrence on cannibalism and intraguild predation among adults. On chapter II, we used second instar nymphs of the predators and pupae of T. molitor ad libitum were given once each four days. When they reach adult stage, couple were formed and we kept same treatment. The survival, cycle of life (second instar until hatch of adults), weigh, sexual ratio, longevity and reproductive aspects of bugs adults and intraguild predation and cannibalism between its nymphs were evaluated. Nymphs and adults of P. nigrispinusand S. cincticeps presented intraguild predation and cannibalism, which favors the survival of some nymphs until localization of the prey. On adult phase, bidirectional intraguild predation and the cannibalism were more frequently to S. cincticeps and increased the longevity of this species. The interespecific competition did not affect the alimentary consume, the predation tax, the development nor the reproduction of P.nigrispinus. The development and reproduction of S. cincticeps were affected, with the nymphal development shorter, production of bigger females and less viability of eggs, showing that this species is less competitive than P. nigrispinus. On higher prey density, these predators presented synergism on predation tax, which is good when it comes to biologic control. It is better to use only P. nigrispinus on inundative and inoculative biologic control, since this species presents higher predation and reproduction taxes. Besides that, the use of this predator with S. cincticeps may be unfavorable, because this is an intraguild predator and may lower P. nigrispinus population on lower prey availability or causes its migration. The low egg viability of S. cincticeps, bred with P. nigrispinus, is an indicative that is better to invest financial resources on P. nigrispinus production. However, in conservative biologic control, the use of both species is interesting because they can coexist at the same environment. Besides that, the egg viability of S. cincticeps presents constant decrease with interspecific interaction with P. nigrispinus, which may lead to a decrease of intraguild predation by this predator. / Presas podem ser mais ou menos consumidas por agentes de controle biológico e predadores apresentam três tipos de interações interespecíficas, (1) sinergismo, aumento da mortalidade da presa em relação a cada inimigo natural de forma independente, quando o comportamento de forrageamento de uma espécie facilita a captura da praga por outros inimigos naturais, (2) mortalidade total da praga por inimigos naturais em conjunto equivale à soma da mortalidade individual por cada um, ocorrem para inimigos naturais independentes, quando predam fases distintas da vida da praga ou em diferentes momentos temporais e (3) mortalidade total da praga por predadores em conjunto é menor que a soma da individual por predador. A diminuição na taxa de predação pode ocorrer devido à predação intraguilda e a competição interespecífica. Podisus nigrispinus (Dallas) e Supputius cincticeps (Stål) (Heteroptera: Pentatomidae), predadores generalistas da região Neotropical da América do Sul, consomem e compartilham alta variedade de presas, não sendo restritos ao nível trófico inferior, pois muitos podem se alimentar uns dos outros, na “predação intraguilda” e no canibalismo. O objetivo deste trabalho foi determinar se existe competição e predação intraguilda entre P. nigrispinus e S. cincticeps. Além disso, estudar o efeito desses fenômenos na biologia desses inimigos naturais e contribuir para a compreensão de interações entre predadores no controle biológico. No capítulo I, fêmeas adultas desses percevejos e pupas de Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae) foram mantidas durante nove dias para a análise das interações intra e interespecíficas no consumo alimentar e na taxa de predação e a ocorrência de canibalismo e predação intraguilda entre adultos. No capítulo II, ninfas de segundo estádio desses predadores foram alimentadas com pupas de T. molitor ad libitum e a cada quatro dias. No estágio adulto, casais foram formados e mantidos nos mesmos tratamentos. A sobrevivência, o ciclo de vida (segundo estádio à emergência dos adultos), peso, razão sexual, longevidade e aspectos reprodutivos dos adultos e a predação intraguilda e canibalismo entre suas ninfas foram avaliados. Ninfas e adultos de P. nigrispinus e S. cincticeps apresentaram predação intraguilda e canibalismo, que favorece a sobrevivência de algumas ninfas, até a localização da presa. Na fase adulta, a predação intraguilda e o canibalismo foram mais frequentes para S. cincticeps e aumentaram a longevidade dessa espécie. A competição interespecífica não afetou o consumo alimentar, a taxa de predação, o desenvolvimento e a reprodução de P. nigrispinus. O desenvolvimento e a reprodução de S. cincticeps foram afetados, com desenvolvimento ninfal mais curto, produção de fêmeas maiores e menor viabilidade de ovos, mostrando ser essa espécie menos competitiva que P. nigrispinus. Em alta densidade de presa, esses predadores apresentaram sinergismo na taxa de predação, o que é benéfico ao controle biológico. É melhor utilizar, apenas, P. nigrispinus nos programas de controle biológico inundativo e inocultaivo, pois essa espécie possui maior taxa de predação e reprodução. Além disso, o uso desse predador, com S. cincticeps, pode ser desfavorável, pois este é o predador intraguilda e pode diminuir a população de P. nigrispinus em baixadisponibilidade de presas, ou causar sua migração. A menor viabilidade de ovos de S. cincticeps, criado com P. nigrispinus, indica ser melhor investir os recursos financeiros na produção de P. nigrispinus. Porém, em programas de controle biológico conservativo, o uso de ambas as espécies é interessante por poderem coexistir no mesmo ambiente. Além disso, a viabilidade dos ovos de S. cincticeps apresenta queda constante com interação interespecífica com P. nigrispinus, o que dimuiria a predação intraguilda por esse predador.
113

Investigação da Atividade Antifúngica do Óleo Essencial de Eugenia caryophyllata Thunb. sobre cepas de Candida tropicalis / Investigation of Antifungal Activity of Essential oil Eugenia caryophyllata Thunb. on strains of Candida tropicalis.

Mendes, Juliana Moura 13 December 2011 (has links)
Made available in DSpace on 2015-05-14T12:59:30Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1755870 bytes, checksum: 96ad104e1f5d7b4eee083c5643e9708f (MD5) Previous issue date: 2011-12-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The candidiasis is a fungal opportunistic infections involving Candida. In Brazil, the specie C. tropicalis is the second most commonly isolated after C. albicans. The emergence of strains resistant to conventional antifungal agents has increased the search for new alternatives from natural products, especially essential oils. This study investigated the activity of essential oil (EO) Eugenia caryophyllata Thunb.(clove) on strains of C. tropicalis by Minimum Inhibitory Concentration (MIC), Minimum Fungicidal Concentration (MFC), Micromorphology, fungal viability (time-kill) and checkerboard. The CIM and CFM were respectively 512 and 1024 μg/mL for the essential oil and 2 μg/mL for amphotericin B. When we evaluated the action of OE and amphotericin B on the morphology of the clinical strain, we observed inhibition of the formation of hyphae and pseudohyphae, which are important virulence factors in the development of candidiasis. There was also the essential oil has a concentration-dependent antifungal activity and that the association of OE and amphotericin B demonstrated effect additive. Given this, it is concluded that the essential oil of E. caryophyllata showed a strong inhibitory activity against C.tropicalis and thus can be considered as a potential product with antifungal properties, especially for the treatment of candidiasis. / As candidíases são infecções fúngicas de caráter oportunista, envolvendo leveduras do gênero Candida. No Brasil, a espécie C. tropicalis é a segunda mais comumente isolada após C. albicans. O surgimento de cepas resistentes aos antifúngicos convencionais tem aumentado a busca por novas alternativas provenientes de produtos naturais, em especial os óleos essenciais. Este trabalho investigou a atividade do óleo essencial (OE) de Eugenia caryophyllata Thunb. (cravo-da-índia) sobre cepas de C. tropicalis, através da Determinação da Concentração Inibitória Mínima (CIM), da Concentração Fungicida Mínima (CFM), do efeito sobre micromorfologia, da viabilidade fúngica (time-kill) e ensaio de sinergismo (checkerboard). A CIM e CFM foram 512 e 1024 μg/mL, respectivamente, para o óleo essencial e 2 μg/mL para anfotericina B. Quando foi avaliada a ação do OE e da anfotericina B sobre a micromorfologia da cepa clínica, observou-se inibição da formação das hifas e pseudohifas, que são fatores de virulência importantes no desenvolvimento das candidíases. Observou-se também o óleo essencial tem atividade antifúngica dependente da concentração e do tempo, e que a associação do OE e anfotericina B demonstrou efeito aditivo.Dessa forma, pode-se concluir que o óleo essencial de E. caryophyllata apresenta forte atividade antifúngica, podendo ser objeto para estudos mais aprofundados acerca dessa atividade.
114

O sinergismo entre a gestão da saúde e segurança ocupacional e a gestão ambiental em empresas construtoras certificadas pelo PBQP-H na Paraíba

Vasconcelos, Diogo Sergio César de 27 May 2011 (has links)
Made available in DSpace on 2015-05-08T14:53:16Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1352142 bytes, checksum: f18d14df02233474b4911a2c8a3c02e6 (MD5) Previous issue date: 2011-05-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Although presenting different performances, Environmental Management and Health and Occupational Safety Management (HOSM) have common and interrelated elements that must be combined to improve the overall process effectiveness, allowing a decision make that preserves the environment, health and worker safety. The possibility of simultaneous association and coordinated action between these two management purposes is called synergism, whose ultimate goal is that the combined performance (each management purpose) is greater than both acting singly. This dissertation was carried out to analyze the synergism between the Health and Occupational Safety Management and Environmental Management in construction companies in João Pessoa/PB. For companies selection participating in this research were used as criteria the existence of certification by the PBQPH (Brazilian Program for Quality and Productivity in Habitat) and management policies addressing environmental issues and HOS in the text. Thus, the research began with the fifteen construction companies certified by the PBQP-H in Paraiba; however, after checking the existence of a management policy addressing the purposes of environmental management and HOS, only four companies remained able to participate in this study. Data collection techniques used included: interviews (with those responsible for management of HOS and Environment) and research in documents provided by companies. By analyzing the synergy between the Environmental Management and HOS management in selected companies, it was come to the conclusion that it is neutral type, ie, purposes of HOS and environment managements do not interact with each other, acting separately. Finally, managers of these companies still need to be aware of the synergy between HOS management and Environmental Management and benefits arising from management of these purposes simultaneously and coordinated. / A Gestão Ambiental e a Gestão de Saúde e Segurança Ocupacional (SSO), embora apresentem abordagens de atuação específicas, possuem elementos comuns e interrelacionados que devem ser combinados a fim de melhorar a efetividade do processo geral, permitindo uma tomada de decisão que preserve ao mesmo tempo o meio ambiente e a saúde e segurança do trabalhador. A possibilidade de associação simultânea e de ação coordenada entre estes dois propósitos de gestão recebe o nome de sinergismo, cujo objetivo final é que a soma das partes (cada propósito de gestão) seja maior que a atuação isolada de cada uma destas. Esta dissertação foi realizada com o objetivo de analisar o sinergismo entre a Gestão da Saúde e Segurança Ocupacional e a Gestão Ambiental em empresas construtoras de João Pessoa/PB. Para a seleção das empresas participantes desta investigação foram utilizados como critérios a existência da certificação pelo PBQP-H (Programa Brasileiro de Qualidade e Produtividade no Habitat) e de uma política de gestão que contemplasse em seu texto questões ambientais e de SSO. Dessa forma, a pesquisa se iniciou com as quinze empresas construtoras certificadas pelo PBQP-H na Paraíba, porém após a verificação da existência de uma política de gestão que contemplasse os propósitos de gestão ambiental e de SSO, apenas quatro empresas permaneceram aptas a participar deste estudo. As técnicas de coletas de dados utilizadas foram: entrevistas (com os responsáveis pela Gestão de SSO e de Meio Ambiente) e pesquisa em documentos fornecidos pelas empresas. Ao analisar o sinergismo entre a Gestão Ambiental e a Gestão de SSO nas empresas selecionadas, chegou-se a conclusão que o mesmo é do tipo neutro, ou seja, os propósitos de gestão de SSO e de meio ambiente não interagem entre si, atuando separadamente. Por fim, pode-se afirmar que os gestores dessas empresas ainda precisam ser conscientizados sobre a sinergia existente entre a Gestão de SSO e a Gestão Ambiental e sobre os benefícios decorrentes da gestão desses propósitos de forma simultânea e coordenada.
115

Extrato de Alecrim (Rosmarinus officinalis L.): Um antioxidante eficiente para uso no biodiesel

Medeiros, Maria Lins de 13 December 2013 (has links)
Made available in DSpace on 2015-05-14T13:21:34Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1973097 bytes, checksum: a4dc548adb2f0f84e7a824393ebfcb86 (MD5) Previous issue date: 2013-12-13 / Biodiesel is susceptible to oxidative processes due to several factors, including the presence of oxygen, heat, light, enzymes, trace of metals, among others. Oxidation stability is an important quality criterium for biodiesel. The literature reports surveys of natural and synthetic antioxidants added to biodiesels from various sources, in order to increase the oxidative stability and thus the lifetime thereof. Beyond this, it provides reducing emissions of toxic gases. In this study, rosemary extracts and synthetic antioxidants were used to retard the oxidation of methyl biodiesel cotton (BA). This biodiesel was additive and stored in carbon steel tanks. During storage, the better oxidative stability was observed, for the biodiesel with the addition of TBHQ and the addition of the mixture of rosemary extract and TBHQ. These antioxidant formulations protected the biodiesel for 90 days, while the ethanol extract of rosemary protected for 60 days and the synthetic antioxidant BHT has not fulfilled the parameters established by ANP. The ethanol extract of rosemary can be considered promising to maintain the quality of biodiesel. Furthermore, the thermal profile obtained by thermogravimetric analysis showed that the ethanolic extract of rosemary may be considered a heat stable since it shows a loss of mass, above 190 ° C. / Biodiesel é suscetível a processos oxidativos devido a vários fatores, incluindo a presença de oxigênio, calor, luz, enzimas, traços de metais, entre outros. A estabilidade à oxidação é um importante critério de qualidade para o biodiesel. A literatura reporta pesquisas feitas com antioxidantes sintéticos e naturais, adicionados à biodieseis de fontes variadas, objetivando aumentar a estabilidade oxidativa e, consequentemente, o tempo de vida útil do mesmo. Além, de proporcionar a redução de emissões de gases tóxicos. Neste estudo, foram utilizados extratos de alecrim e antioxidantes sintéticos para retardar a oxidação do biodiesel metílico do óleo de algodão. Este biodiesel foi aditivado e armazenado em depósitos de aço carbono. Durante o armazenamento, foi observada a melhor estabilidade oxidativa de biodiesel adicionado com TBHQ e com a mistura de extrato de alecrim com TBHQ. Estas formulações antioxidantes protegeram o biodiesel por 90 dias, enquanto que o extrato etanólico de alecrim protegeu por 60 dias e o antioxidante sintético BHT não cumpriu os parâmetros estabelecidos pela Agência Nacional do Petróleo,Gás Natural e Biocombustíveis. O extrato etanólico de alecrim pode ser considerado promissor para manter a qualidade do biodiesel. Além disso, o perfil térmico obtido por análise termogravimétrica mostrou que o extrato etanólico de alecrim pode ser considerado um termoestável, uma vez que mostrou uma perda de massa, provavelmente, acima de 190 °C.
116

Atividade formicida de Aristolochia trilobata L. (Aristolochiaceae) sobre formigas cortadeiras / Ant activity of Aristolochia trilobata L. (Aristolochiaceae) on leaf-cutting ants

Oliveira, Bruna Maria Santos de 27 February 2015 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Leaf-cutting ants of Atta and Acromyrmex genus (Hymenoptera: Formicidae) are common insects in the Neotropics region and an important pests in agricultural environments. These organisms are often controlled using organosintetics insecticides, however, mostly products are inefficient. This problem has generated a growing demand for environmentally safe products to control these pests. Thus, in order to contribute with new methods of control, the aim of this work was to evaluate the ant activity of essential oil of A. trilobata and its major compounds on cutting ants Atta sexdens and Acromyrmex balzani. Initially, it was performed toxicity bioassays by two different routes of exposure - contact and fumigation. Once determined the exposure way with the best ant activity, this route was choosed to performe the next experiments, bioassay toxicity (lethal concentration and time), effects of binary mixtures (synergistic, additive and antagonistic) of major compounds, repellency and irritability. The essential oil of A. trilobata was obtained by hydrodistillation of the dried stem and the identification / quantification of compounds was performed by GC/MS/FID. Twenty Five compounds were identified in the essential oil of A. trilobata, that are mostly composed of monoterpenes. The major constituents were the monoterpenes: sulcatyl acetate (25.64%), limonene (24.80%), p-cymene (10.41%) and linalool (9.51%). The essential oil of A. trilobata and their major compounds were effective against workers of A. balzani and A. sexdens when the route of exposure was fumigation. These compounds have demonstrated efficient activity on ant species A. balzani and A. sexdens, with LCs50 ranging from 2.18 to 6.73 uL mL-1. The monoterpenes linalool and sulcatyl acetate when applied alone were 1.6 and 1.7 times more toxic than the essential oil against A. balzani. As for A. sexdens, p-cymene was 1.6 times more toxic than the essential oil of A. trilobata. Workers of A. sexdens were more tolerant to the essential oil, linalool and sulcatyl acetate. The essential oil of A. trilobata and its major compounds acted faster on A. sexdens compared to A. balzani. On average, these compounds took 29.3 and 11.3 hours to cause mortality in half population of A. balzani and A. sexdens, respectively. The major compounds of the essential oil of A. trilobata acted synergistically in toxicity of A. balzani. As for A. sexdens most combinations of the compounds exhibited an additive effect. The essential oil of A. trilobata and its major compounds were repellent and caused great irritability to workers of A. balzani and A. sexdens. Thus, our results show a great potential of the essential oil of A. trilobata and its major compounds for develop new insecticides. / As formigas cortadeiras dos gêneros Atta e Acromyrmex (Hymenoptera: Formicidae) são insetos comuns na região neotropical e importantes pragas em ambientes agrícolas. Estes organismos são frequentemente controlados com o uso de inseticidas organossintéticos, no entanto, este método de controle é muitas vezes ineficiente. Isso tem gerado uma demanda crescente na busca de alternativas de controle que sejam ambientalmente sustentáveis. Assim, com o intuito de contribuir no controle, objetivou-se com este trabalho avaliar a atividade formicida do óleo essencial de Aristolochia trilobata e de seus compostos majoritários sobre as formigas cortadeiras Atta sexdens e Acromyrmex balzani. Para isso, foram realizados inicialmente bioensaios de toxicidade por duas diferentes vias de exposição - contato e fumigação. Uma vez determinada a via de exposição com melhor atividade formicida foram realizados, por esta via de exposição, bioensaios de toxicidade (concentração e tempo letal), efeitos das misturas binárias (sinergismo, aditismo e antagonismo) dos compostos majoritários, repelência e irritabilidade. O óleo essencial de A. trilobata foi obtido por hidrodestilação do caule seco e a identificação/quantificação dos compostos foi realizada por CG/EM/DIC. Foram identificados 25 compostos no óleo essencial de A. trilobata, sendo a sua maioria formada por monoterpenos. Os constituintes em maiores proporções foram os monoterpenos: acetato de sulcatila (25,64%), limoneno (24,80%), p-cimeno (10,41%) e linalol (9,51%). O óleo essencial de A. trilobata e seus compostos majoritários isolados foram eficientes contra operárias de A. balzani e A. sexdens quando a via de exposição foi fumigação. Estes compostos demonstraram eficiente atividade formicida sobre as espécies, com CLs50 variando de 2,18 a 6,73 μL mL-1. Os monoterpenos linalol e acetato de sulcatila quando aplicados isoladamente foram 1,6 e 1,7 vezes mais tóxicos do que o óleo essencial de A. trilobata para A. balzani. Já para A. sexdens, o composto p-cimeno foi 1,6 vezes mais tóxico do que o óleo essencial. Operárias de A. sexdens foram mais tolerantes ao óleo essencial de A. trilobata e aos compostos linalol e acetato de sulcatila. O óleo essencial de A. trilobata e seus compostos majoritários atuaram de forma mais rápida sobre A. sexdens em comparação a A. balzani. Na média, estes compostos demoraram 29,3 e 11,3 horas para causar mortalidade na metade das populações de A. balzani e A. sexdens, respectivamente. Os compostos majoritários do óleo essencial de A. trilobata atuaram de forma sinérgica na toxicidade sobre A. balzani. Já para a espécie A. sexdens a maioria das combinações entre os compostos exibiu efeito aditivo. O óleo essencial de A. trilobata e seus compostos majoritários foram repelentes e causaram grande irritabilidade às operárias de A. balzani e A. sexdens. Assim, nossos resultados mostram o grande potencial do óleo essencial de A. trilobata e seus compostos majoritários para o desenvolvimento de novos formicidas.
117

Estudo do efeito do fator estimulador de colônia de granulócitos associado a metilprednisolona na lesão medular aguda experimental em ratos / Study of the effect of granulocyte colony-stimulating factor associated with methylprednisolone in experimental acute spinal cord injury in rats

William Gemio Jacobsen Teixeira 29 August 2017 (has links)
Introdução: Várias são as propostas descritas para tratar farmacologicamente a lesão traumática da medula espinal. A metilprednisolona já foi padronizada para uso clínico. O fator estimulador de colônia de granulócitos (G-CSF) tem sido promissor em estudos experimentais e clínicos. Não há pesquisas quanto ao efeito da associação dos dois fármacos. Objetivo: Avaliar o efeito do tratamento com o fator estimulador de colônia de granulócitos associado a metilprednisolona na lesão medular aguda experimental em ratos. Material e métodos: Foram avaliados 40 ratos Wistar submetidos a lesão medular moderada com o NYU-Impactor. Os animais foram divididos em quatro grupos de 10 ratos. O Grupo Controle não recebeu tratamento; o Grupo G-CSF, foi tratado com G-CSF no momento da lesão e diariamente ao longo dos cinco dias subsequentes; o Grupo Metilprednisolona, com metilprednisolona durante 24 horas; e o Grupo G-CSF/Metilprednisolona, com metilprednisolona durante 24 horas e G-CSF no momento da lesão e ao longo de cinco dias. Os animais foram mantidos vivos durante 42 dias; a avaliação funcional foi realizada com a aplicação da escala funcional de Basso, Beattie e Bresnahan (BBB) nos dias 2, 7, 14, 21, 28, 35 e 42 subsequentes à lesão. A avaliação dos potenciais evocados motores foi realizada no dia 42 e a avaliação histológica da lesão da região da medula espinal lesada, realizada logo após a eutanásia ocorrida no dia 42. Resultados e conclusões: A associação de metilprednisolona e G-CSF no tratamento do traumatismo medular contuso experimental em ratos promoveu melhora neurológica avaliada pela escala BBB superior à melhora promovida pela metilprednisolona e G-CSF quando utilizadas isoladamente. A associação teve também efeito sinérgico que resultou em melhora nos parâmetros histológicos no local da lesão. Não houve diferença entre os grupos quanto à avaliação neurofisiológica / Introduction: There are several proposals to pharmacologically treat traumatic spinal cord injury. Methylprednisolone has already been standardized for clinical use. Granulocyte colony stimulating factor (G-CSF) has been promising in experimental and clinical studies. There is no research on the effect of the association of the two drugs. Objective: to evaluate the effect of combined treatment of the granulocyte colony-stimulating factor (G-CSF) associated with methylprednisolone in experimental acute spinal cord injury in rats. Material and methods: Forty male Wistar rats were submitted to a moderate spinal cord injury with the NYU-Impactor. The animals were divided into four groups of ten rats each. The Control Group was not treated; the G-CSF Group was treated with G-CSF at the time of injury and daily over the next five days; the Methylprednisolone Group was treated with methylprednisolone for 24 hours; the G-CSF/methylprednisolone Group, was treated with methylprednisolone for 24 hours and G-CSF at the time of injury and daily over the next five days. The animals were kept alive for 42 days; Functional evaluation was performed using the Basso, Beattie and Bresnahan (BBB) score on days 2, 7, 14, 21, 28, 35 and 42 following the spinal cord injury. Evaluation of motor evoked potentials was held and histological examination of the lesion of the spinal cord was done immediately after euthanasia on day 42. Results and conclusions: The combination of methylprednisolone and G-CSF in the treatment of experimental spinal cord injury in rats promoted neurological improvement as assessed by BBB scale with greater improvement than with methylprednisolone or G-CSF when used alone. The combination of treatment had also a synergistic effect resulting in improvement in histological parameters at the injury site. There was no difference between groups regarding neurophysiological evaluation
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Versatile silicone rubber samplers for trace organic analysis in a chromatography-mass spectrometry laboratory

Naude, Yvette 05 April 2013 (has links)
Extraction is required to separate and concentrate trace level analytes from the sample matrix prior to gas chromatography (GC). Classical extraction procedures utilise large amounts of hazardous solvents, generate waste, and sensitivity limitations are associated with the injection of microlitre amounts of the final solvent extract. In response to real world challenges, and to overcome the problems associated with solvent extraction, novel silicone rubber (polydimethylsiloxane (PDMS)) samplers were developed for solvent free enrichment of trace level analytes from indoor air, contaminated soil, desert soil, ultra high temperature (UHT) milk and Pinotage wine. Versatile PDMS samplers as a loop, a multichannel trap, or a denuder for trace environmental forensics, geochemical and aroma investigations are presented. A unique off-line multidimensional GC approach involving heart-cut gas chromatographic fraction collection is described, as is off-line olfactory assessment of recombined heart-cuts for synergistic odour effects. PDMS loop samplers were used for the extraction of DDT (1,1,1- trichloro-2,2-bis(p-chlorophenyl)ethane) and its associated environmental pollutants from soil samples. Miniature denuder samplers accomplished separate concentration of vapour phase and of particulate phase fractions of DDT and its associated environmental pollutants from indoor air, in a single step. Ratios of airborne p,p’-DDD/p,p’-DDT and of o,p’-DDT/p,p’-DDT are unusual and do not match the ideal certified ingredient composition required of commercial DDT. Results suggest that commercial DDT used for indoor residual spraying may have been compromised with regards to insecticidal efficacy, demonstrating the power of this new environmental forensics tool. Multichannel PDMS trap samplers were used in a unique heart-cut multidimensional GC approach for off-line enantiomeric separation of o,p’-DDT and o,p’-DDD in air and soil. This alternative multidimensional method is compared to the complementary technique of comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GCxGC-TOFMS). PDMS loop samplers were also employed for the solvent free extraction of hydrocarbons from desert soil to investigate, for the first time, a possible geochemical origin of the enigmatic fairy circles of Namibia. It is proposed that microseepages of natural gas and low volatility hydrocarbons are expressed at the surface as a geobotanical anomaly of barren circles and circles of altered vegetation. Multichannel PDMS trap samplers were utilised for sampling of the headspace of UHT milk and of Pinotage wine, and to study off-line, using a portable olfactometer, synergistic effects between recombined heart-cut aroma compounds. Olfactory results show that a synergistic combination of 2- heptanone and 2-nonanone was responsible for a pungent cheese-like odour in UHT milk, while a synergistic combination of furfural and 2-furanmethanol was responsible for a roast coffee bean-like odour in coffee style Pinotage wine. The small, low cost samplers are quick and easy to assemble and they fit commercial thermal desorber systems. The PDMS samplers are reusable. Solvent extraction of the sampling materials, extract clean-up and pre-concentration are not required. Thus, potential loss of analyte, introduction of contaminants and waste disposal are minimised. Solvent free thermal desorption permits transfer of the entire sample mass to the cooled injection system (CIS) inlet of a GC resulting in greater sensitivity when compared to injection of microlitre amounts of a solvent extract. This allowed for sampling of smaller sized soil samples, shorter air sampling times and lower air sampling flow rates when compared to solvent based methods. / Thesis (PhD)--University of Pretoria, 2013. / Chemistry / unrestricted
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Prediction of antibiotic mass flows in urban catchments and their environmental prioritization

Marx, Conrad 09 December 2015 (has links)
Urban emissions of antibiotics into the environment have the potential to adversely affect terrestrial and aquatic organisms. Developed standardized test methods allow the quantification of the resulting ecotoxicological risk, which strongly relies on a comprehensive situation analysis by predicting or measuring a representative antibiotic concentration of interest. Predicting the input loads of antibiotics to wastewater treatment plants using secondary input data (e.g. prescriptions) is a reasonable method if no analytical data is available. The absence of such data poses the question of an aquired reasonable sample quantity to capture local seasonal differences in prescriptions as well as flow conditions within the catchment area. Both, the theoretical and measurement based determination of environmental concentrations have been scarcely verified in practice. Hence, high resolution prescription data in combination with an extensive monitoring campaign at the wastewater treatment plant Dresden-Kaditz (WWTP) were used as a basis to evaluate the reliability of predicting and measuring urban antibiotic emissions. As expected, the recovery of antibiotic input loads strongly varies among substances. The group of macrolides as well as sulfamethoxazole and trimethoprim were almost fully recovered whereas nearly all substances of the beta-lactam family exhibit high elimination rates during the wastewater transport in the sewer system. Yet other antibiotics (e.g. fluoroquinolones) show distinct fluctuations through the year, which was not obvious from relatively constant prescriptions. The latter substances are an example that available data are not per se sufficient to predict the actual release into the environment which, in certain cases, emphasizes the necessity of adequate measuring campaings. The extensive data pool of this study was hence used to calculate the necessary number of samples to determine a representative annual mean load to the WWTP. Based on the applied approach, a minimum number of 20 to 40 samples per year is proposed to reasonably estimate a representative annual input load of antibiotics and other micropollutants. Regarding the WWTP, the mass flow analysis revealed that macrolides, clindamycin/ clindamycin-sulfoxide and trimethoprim were mainly released with the effluent, while penicillins, cephalosporins as well as sulfamethoxazole were partly degraded in the studied WWTP. Levofloxacin and ciprofloxacin are the only antibiotics under investigation with a significant mass fraction bound to primary, excess and digested sludge. In this context, the sludge concentrations are considered to be highly inconsistent which leads to questionable results. It remains unclear whether the inconsistencies are due to insufficiencies in sampling and/or analytical determination or if the fluctuations can be considered reasonable for digesters. Subsequently, verified antibiotic loads were evaluated regarding their ecotoxicological effects in the aquatic environment. Two approaches were applied (1) to address the ecological impact on individual trophic levels algae, daphnia and fish, and (2) to assess the possible synergistic potential of antibiotic combinations. Ciprofloxacin, levofloxacin and the group of cephalosporins showed to significantly affect the aquatic environment. They either have the highest impact on (one of) the lowest trophic level(s) or disproportionately increase the ecotoxicological risk due to their synergistic characteristics. In this regard, the deficiencies regarding the input prediction of these antibiotics is of particular concern. The underestimation of such critical mass flow conditions weakens the approach of assessing environmental risks on the basis of secondary data like prescriptions. Hence, efforts must be made to further develop the projection model by improving the quality of secondary data, identifying additional emitters and understanding possible retention and degradation dynamics of antibiotics within the sewer system.:Abstract 2 Danksagung 1 Table of Contents 1 Chapter 1 – Introduction 1 Scope 1 Goals and structure 3 Approach and Methods 5 Chapter 2 – Representative input load of antibiotics to WWTPs: Predictive accuracy and determination of a required sampling quantity 11 Introduction 14 Materials and Methods 16 Results and discussion 24 Conclusion 38 References 39 Chapter 3 – Mass flow of antibiotics in a wastewater treatment plant focusing on removal variations due to operational parameters 41 Introduction 45 Materials and Methods 47 Results and discussion 52 Conclusions 65 References 66 Chapter 4 – Species-related risk assessment of antibiotics using the probability distribution of long-term toxicity data as weighting function – a case study 71 Introduction 74 Materials and Methods 75 Results and discussion 86 Conclusions and summary 93 References 95 Chapter 5 – Environmental risk assessment of antibiotics including synergistic and antagonistic combination effects 99 Materials and Methods 104 Results 113 Discussion 120 Conclusions and summary . 125 References 126 Chapter 6 – Results and conclusions 129 Individual results 131 Aggregation of results 133 Final conclusions 134 References 139 Annex 1 – Supplementary material Chapter 2 141 Annex 2 – Supplementary material Chapter 3 147 Annex 3 – Supplementary material Chapter 4 159 Annex 4 – Supplementary material Chapter 5 177 / In der Humanmedizin eingesetzte Antibiotika werden im menschlichen Körper nicht vollständig metabolisiert und gelangen über die Ausscheidungen in das kommunale Abwasser. In der Kläranlage erfolgt nur eine unvollständige Elimination dieser Stoffe, so dass der Kläranlagenablauf einen Hot Spot für Antibiotikaemissionen in die Umwelt darstellt. Das induzierte ökotoxikologische Risiko kann anhand standardisierter Testverfahren und allgemein anerkannter Bewertungsansätze für Einzelsubstanzen abgeschätzt werden. Erfolgt jedoch die Betrachtung von Antibiotikagemischen, wie es für den gereinigten Ablauf einer Kläranlage sinnvoll ist, sind aufgrund zumeist unspezifischer Wirkmechanismen und dem Mangel an repräsentativen Daten eine Reihe von Vereinfachungen und Annahmen zu treffen. Es besteht in der Folge die Gefahr einer Unterschätzung des durch Substanzgemische hervorgerufenen ökotoxikologischen Risikos. Eine vielversprechende Möglichkeit den Entscheidungsprozess über mögliche Vermeidungs- und Eliminationsmaßnahmen zu unterstützen besteht in der Priorisierung von Antibiotika entsprechend ihres Effektpotentials. Hierbei sind Substanzen zu identifizieren, die den größten Einfluss auf die Nahrungskette im Gewässer bzw. das höchste (negative) Synergiepotential mit anderen Substanzen aufweisen. Die Verringerung dieser Substanzen führt zu einer hohen ökologischen Effektivität und Effizienz der eingesetzten Mittel. Wie im Fall des klassischen Bewertungsansatzes, ist auch für den Priorisierungsansatz eine umfängliche und zuverlässige Situationsanalyse die Grundvoraussetzung für verwertbare Ergebnisse. Die Situationsanalyse beruht auf der analytischen Bestimmung bzw. der Abschätzung von emittierten Antibiotikafrachten zur Berechnung von repräsentativen Umweltkonzentrationen. Analytisch ermittelte Umweltkonzentrationen vieler Antibiotika weisen aufgrund saisonaler Verschreibungsmuster eine hohe zeitliche und räumliche Variabilität auf. Die für eine adäquate Erfassung der Situation notwendigen Messkampagnen sind kostenintensiv, wobei die tatsächlich notwendige Häufigkeit der Probenahme von zumeist nicht hinreichend bekannten substanzspezifischen Informationen, wie der chemischen Stabilität im Rohabwasser und der saisonal beeinflussten Applikation, abhängt. Alternativ können Antibiotikaeinträge in die Kanalisation anhand von Verschreibungsdaten abgeschätzt und mit Hilfe von Stoffflussanalysen (SFA) zur ökotoxikologischen Bewertung herangezogen werden. Eine vom Umfang befriedigende, direkte Gegenüberstellung von prognostizierten und analytisch ermittelten Frachten ist bisher jedoch nicht erfolgt, so dass die Verifizierung dieses Ansatzes noch aussteht. Für den Fall einer bestehenden Verschreibungspflicht für Antibiotika besitzen Verschreibungsdaten eine vergleichsweise hohe zeitliche und räumliche Informationsgüte. In Verbindung mit einer an diese Datenqualität angepassten Messkampagne, ergibt sich die Möglichkeit einer detaillierten SFA mit substanzspezifischer Bewertung der Eignung des Prognoseansatzes. Die am Beispiel der Stadt Dresden durchgeführte Bewertung des Prognoseansatzes fußt auf einer 15-monatigen Messkampagne und den für das Einzugsgebiet der Zentralkläranlage Dresden-Kaditz verfügbaren Verschreibungsdaten der AOK PLUS. Erwartungsgemäß ergibt der Abgleich von erwarteten und analytisch ermittelten Frachten eine starke Variation der für den Zulauf der Kläranlage ermittelten Wiederfindungsdaten verschiedener Substanzen. Die analytisch ermittelten Frachten von Sulfamethoxazol, Trimethoprim sowie der Gruppe der Makrolid-Antibiotika entsprechen nahezu den prognostizierten Mengen. Die Beta-Laktam-Antibiotika unterliegen bereits während des Abwassertransports einer umfänglichen, zumeist biologisch bedingten, Elimination, was zu hohen Unterbefunden im Zulauf der Kläranlage führt. Andere Substanzen hingegen (z.B. Fluorchinolone) weisen messtechnisch eine signifikante Jahresdynamik auf, die aufgrund der weitgehend konstanten Verschreibung in dieser Ausprägung nicht zu erwarten ist. Die Auswertung zuletzt genannter Substanzen zeigt deutlich, dass die Nutzung von Verschreibungsdaten nicht per se ausreicht, um die Emission von Antibiotika (und anderer Pharmazeutika) sowie die sich daraus ergebenden Umweltkonzentrationen mit ausreichender Sicherheit prognostizieren zu können. Für eine nachgelagerte ökotoxikologische Bewertung ist in diesen Fällen die Durchführung von Messungen unumgänglich. Zur effizienten Planung derartiger Kampagnen wurde der umfassende Datenpool dieser Studie hinsichtlich der erforderlichen Probenanzahl zur Bestimmung einer repräsentativen mittleren Jahresfracht ausgewertet. Es ergibt sich ein Minimum von 20 bis 40 homogen über das Jahr verteilten Proben, um die jährlich in die Kläranlage eingetragene Fracht an Antibiotika bzw. anderer Mikroschadstoffe mit ausreichender Sicherheit abschätzen zu können. Im Rahmen der SFA in der Kläranlage Dresden-Kaditz wird deutlich, dass Makrolide, Clindamycin und dessen Humanmetabolit Clindamycin-Sulfoxid sowie Trimethoprim in der nahezu keiner Elimination unterliegen, wohingegen Penizilline, Cefalosporine und auch Sulfamethoxazol teilweise bis vollständig abgebaut werden. Mit Levofloxacin und Ciprofloxacin handelt es sich um die einzigen untersuchten Antibiotika, welche zu einem signifikanten Massenanteil an Primär-, Überschuss- und Faulschlamm gebunden vorgefunden werden. Aufgrund der hohen Relevanz dieses Eliminationspfades für die zuvor genannten Antibiotika bedarf die Beobachtung von z. T. widersprüchlichen Schwankungen einer kritischen Betrachtung der Ergebnisse. Es ist nicht abschließend geklärt, ob die beobachteten Fluktuationen auf eine unzureichende Qualität der Probenahme und/oder der Analytik zurückzuführen sind oder sich die Schwankungen in einem für Faulbehälter tolerierbaren Bereich befinden. Im Anschluss an die verifizierten Antibiotikaemissionen erfolgte die Priorisierung der betrachteten Antibiotika nach ihrem ökotoxikologischen Effektpotential. Zum einen wurde der ökologische Einfluss auf verschiedene, die Nahrungskette bildende trophische Ebenen (Alge, Daphnie, Fisch) untersucht. In Anlehnung an die humanmedizinische Kombinationstherapie erfolgte im zweiten Ansatz die Beurteilung der Antibiotika hinsichtlich ihres möglichen Potentials zur Verstärkung von negativen Effekten durch das gleichzeitige Auftreten mit anderen Substanzen. Für Ciprofloxacin, Levofloxacin und die Gruppen der Makrolide und Cefalosporine konnten signifikante Beeinträchtigungen der aquatischen Umwelt nachgewiesen werden. Diese Stoffe und Stoffgruppen führten im Rahmen der untersuchten Substanzen entweder zur höchsten Schadwirkung gegenüber der niedrigsten trophischen Ebene oder besitzen das höchste Synergiepotential in Kombination mit anderen Substanzen. Die Auswertung der SFA bestätigt die grundsätzliche Eignung der Verschreibungsdaten sowie des entwickelten Prognosemodells zur Vorhersage von Antibiotikaemissionen im urbanen Raum. Die Stoffflussanalyse stellt somit ein strategisches, im Vergleich zur Messung kostengünstiges Instrument zur Identifikation von Hot Spots der Antibiotikaemission dar und erleichtert die Entscheidungsfindung für monetär aufwendige Reduktionsmaßnahmen am Ort der Entstehung oder in der Kläranlage (z.B. 4. Reinigungsstufe). Die Vorgehensweise zur Priorisierung von Substanzen hinsichtlich ihres ökotoxikologischen Effektpotentials eignet sich sehr gut, Antibiotika mit dem höchsten Schadpotential zu identifizieren. Die Verschneidung der Kenntnis dieser Substanzen mit den Ergebnissen der SFA macht deutlich, dass mit Ausnahme der Makrolide, alle ökotoxikologisch priorisierten Antibiotika eine mangelhafte Prognosefähigkeit aufweisen. Die unvollständige Abbildung kritischer Stoffströme, wie z.B. Frachtspitzen, führt insbesondere im Fall der ökotoxikologisch priorisierten Substanzen zu einer Minderung der Aussagekraft des auf Verschreibungsdaten beruhenden Prognoseansatzes. An diesem Punkt ist in zukünftigen Betrachtungen anzusetzen, um die Qualität von Verschreibungsdaten zu verbessern, potentiell nicht erfasste Emittenten in die Betrachtungen einzubeziehen, sowie die Dynamik der Rückhalte- und Eliminationsprozesse in der Kanalisation adäquat beschreiben zu können. Die ergänzende Betrachtung weiterer Anlagentechnologien (z.B. Festbettreaktoren) kann zur Bestätigung der am Beispiel der Kläranlage Dresden-Kaditz gewonnenen Ergebnisse beitragen bzw. Unterschiede bei der Elimination von Antibiotika das Potential, die Problematik der Antibiotika und anderer Mikroschadstoffe bereits während der Planung von Abwasseranlagen berücksichtigen zu können.:Abstract 2 Danksagung 1 Table of Contents 1 Chapter 1 – Introduction 1 Scope 1 Goals and structure 3 Approach and Methods 5 Chapter 2 – Representative input load of antibiotics to WWTPs: Predictive accuracy and determination of a required sampling quantity 11 Introduction 14 Materials and Methods 16 Results and discussion 24 Conclusion 38 References 39 Chapter 3 – Mass flow of antibiotics in a wastewater treatment plant focusing on removal variations due to operational parameters 41 Introduction 45 Materials and Methods 47 Results and discussion 52 Conclusions 65 References 66 Chapter 4 – Species-related risk assessment of antibiotics using the probability distribution of long-term toxicity data as weighting function – a case study 71 Introduction 74 Materials and Methods 75 Results and discussion 86 Conclusions and summary 93 References 95 Chapter 5 – Environmental risk assessment of antibiotics including synergistic and antagonistic combination effects 99 Materials and Methods 104 Results 113 Discussion 120 Conclusions and summary . 125 References 126 Chapter 6 – Results and conclusions 129 Individual results 131 Aggregation of results 133 Final conclusions 134 References 139 Annex 1 – Supplementary material Chapter 2 141 Annex 2 – Supplementary material Chapter 3 147 Annex 3 – Supplementary material Chapter 4 159 Annex 4 – Supplementary material Chapter 5 177
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The Interplay of Familial Depression Liability and Adverse Events in Predicting the First Onset of Depression During a 10-Year Follow-up

Zimmermann, Petra, Brückl, Tanja, Lieb, Roselind, Nocon, Agnes, Ising, Marcus, Beesdo, Katja, Wittchen, Hans-Ulrich January 2008 (has links)
Background: The aim of the present article is to explore interaction and correlation effects between familial depression liability and selected adverse (separation and traumatic) events in predicting the first onset of a major depressive episode (MDE) in a 10-year prospective longitudinal community survey. Methods: Analyses are based on 1982 subjects (14 to 24 years at baseline) without baseline MDE who participated during the whole study period and for whom diagnostic information about psychopathology in both parents was available. The offspring’s familial depression liability was determined by aggregating information on parental depressive symptoms obtained from family history data and direct interviews with parents. Data were assessed with the Munich-Composite International Diagnostic Interview according to its DSM-IV algorithms. Results: Adverse events predicted a substantially increased incidence of MDE among respondents with familial liability but not in those without familial liability. There was a significant interaction between familial liability and traumatic events with the strongest effect for the number of severe traumatic events (risk difference = 11.3%; 95% confidence interval = 3.55–19.15). Associations with familial liability were most pronounced for separation events. Conclusions: Adverse events are particularly pathogenic in individuals with familial liability. The involvement of interactions and correlations between familial liability and adversity might depend on type, severity, and number of events. Both processes are suggested to be concomitant rather than exclusive.

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