33 research outputs found

    SÍNTESE E CARACTERIZAÇÃO DE NANOPARTÍCULAS DE CU-ZNO E SUA UTILIZAÇÃO NO REVESTIMENTO DE SUPERFÍCIES DE TITÂNIO POR DEPOSIÇÃO ELETROFORÉTICA.

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    Grande parte dos insucessos das cirurgias de transplante metálico ocorre devido à rejeição corporal à superfície do material empregado e às infecções pós-operatórias na região implantada. Dessa forma, prevenir o crescimento bacteriano sobre esses materiais e simultaneamente contribuir para a sua adaptação ao organismo são as principais metas de pesquisas recentes em nanomedicina. Como uma forma de alcançar esses objetivos, o revestimento de próteses metálicas com nanopartículas representa uma alternativa viável aos métodos tradicionais de tratamento, como por exemplo, o uso de antibióticos cuja eficácia decresce com o surgimento de cepas resistentes. Nesse trabalho, foi realizada a aplicação de nanopartículas de óxido de zinco dopado com cobre (Cu-ZnO) para o revestimento de superfícies de titânio metal comumente utilizado em implantes artificiais, a partir da técnica de deposição eletroforética. A escolha das nanopartículas de Cu-ZnO foi pautada em suas características antibacterianas, como demonstrado na literatura. Utilizando as técnicas de caracterização por microscopia (MEV e MET), espectroscopia (EDS) e difração de raios-X (DRX), pôde-se confirmar seu formato e os elementos presentes nas nanopartículas bem como o tamanho médio do cristalito (228,24 nm) e os parâmetros de rede. As nanopartículas foram suspensas e depositadas por eletroforese em placas de titânio por 1 minuto sob tensões entre 100 e 180 V a fim de se obter a melhor condição de deposição, sendo esta a de 160 V. O pH e a condutividade elétrica da suspensão também foram avaliados antes e após a EPD. Os resultados de EDS confirmaram a presença do nanomaterial no depósito e as imagens obtidas por MEV confirmaram o aumento da rugosidade superficial após a deposição eletroforética. Assim sendo, almejou-se nesse trabalho explorar o potencial de dessa técnica para o revestimento em implantes artificiais e, por conseguinte, contribuir para a pesquisa em nanotecnologia e suas aplicações em medicina

    Nematicidal activity of Paecilomyces marquandii proteases on infective larvae of Ancylostoma spp

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    ABSTRACT The present study aimed to evaluate the action of Paecilomyces marquandii proteases on Ancylostoma spp L3. White halos in the zymogram confirmed the proteolytic action. Difference (p <0.01) between the number of L3 in the differents groups was found, with 41.4% of reduction of Ancylostoma spp. L3 before 24 hours

    Scarabaeoidea (Insecta : Coleoptera) in the Brazilian Cerrado : current state of knowledge

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    Besouros pertencentes à superfamília Scarabaeoidea ocupam habitats variados, possuem hábitos alimentares diversifi cados, desempenham importante papel ecológico e diversas espécies apresentam importância agrícola. No entanto, estudos com esse grupo na região do Cerrado são escassos. Nesta revisão realizou-se um levantamento dos artigos publicados nos últimos 30 anos a respeito dos Scarabaeoidea no Cerrado. Foram recuperados 64 artigos, realizados em nove unidades da federação, que focavam quatro temas principais espécies praga, aspectos bioecológicos, biodiversidade e importância ecológica, e técnicas e metodologias de coleta de Scarabaeoidea. Os resultados desta revisão indicam que poucos estudos foram realizados com os Scarabaeoidea no Cerrado brasileiro nas últimas décadas frente à importância e diversidade desse grupo de insetos.Beetles belonging to the superfamily Scarabaeoidea occupy different habitats, present feeding habits diversifi ed, play an important ecological role and several species have agricultural importance. However, studies with this group in the Brazilian Cerrado are scarce. In this review we carried out a survey of scientifi c articles published in the past 30 years concerning Scarabaeoidea in the Cerrado. Were found 64 studies in nine Brazilian states. The studies focused on four main topics: pest species, bioecology, biodiversity and ecological importance, techniques and methodologies for collecting Scarabaeoidea. The results of this review indicate that few studies have been conducted with Scarabaeoidea in the Cerrado in recent decades compared to the importance and diversity of this group of insects

    Structure and kinematics of the Siviez-Mischabel nappe in the Mattertal (western Alps of Switzerland) = Structure et cinématique de la nappe de Siviez-Mischabel le long de la vallée de Zermatt (Alpes de Suisse occidentale)

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    Résumé Cette étude porte sur le flanc inverse de la nappe de Siviez-Mischabel et sur les unités tectoniques sous jacentes (zone de Stalden supérieur et zone Houillère) dans la vallée menant à Zermatt. L'étude structurale du granite permien de Randa (orthogneiss oeillé) permet de mieux comprendre les effets de la déformation alpine sur les roches de socle. La cartographie détaillée de l'orthogneiss et de son encaissant, ainsi que l'étude lithostratigraphique des terrains sédimentaires associés permettent de proposer un schéma structural et cinématique du flanc inverse de la nappe de Siviez-Mischabel et de mieux comprendre ses relations avec les unités tectoniques sous-jacentes. L'analyse structurale de l'orthogneiss de Randa et de son encaissant révèle la superposition de plusieurs phases de déformation ductile. Cet orthogneiss formé sous des conditions métamorphiques du faciès schiste vert possède une forte schistosité alpine avec au moins deux linéations d'extension. La première, L1, orientée NW-SE est associée à la mise en place de la nappe. La seconde, L2, orientée SW-NE, se corrèle au cisaillement ductile du Simplon. La quantification de la déformation au moyen de la méthode de Fry sur les faciès porphyriques donne des ellipses à rapports axiaux compris entre 1.9 et 5.3, en accord avec les valeurs obtenues par d'autres marqueurs {tourmalines étirées, fibres). Les valeurs mesurées parallèlement à L1 ou L2 sont très semblables. La méthode de Fry a nécessité une étude théorique préalable afin de vérifier son applicabilité aux orthogneiss oeillés. La méthode requiert une distribution spatiale homogène et isotrope des marqueurs utilisés. Les tests statistiques effectués ont révélé que les phénocristaux de feldspath alcalin satisfont à cette condition et qu'ils peuvent être utilisés comme marqueur de la déformation au moyen de la méthode de Fry. Les valeurs obtenues révèlent l'importance du cisaillement ductile du Simplon sur la géométrie de la nappe dans la région d'étude. Le levé cartographique a permis d'améliorer la lithostratigraphie de la base de la nappe de Siviez-Mischabel. Trois formations en position renversée peuvent être observées sous les gneiss formant le coeur de la nappe. Ces trois formations forment le coeur du synclinal de St-Niklaus qui connecte la nappe de Siviez-Mischabel à la zone de Stalden supérieur. La datation par U-Pb de zircons détritiques et magmatiques par LA-ICP-MS permet de contraindre l'âge des formations observées (probablement Carbonifère à Trias précoce). Ces données ont des répercussions importantes sur la structure de la nappe dans la région, prouvant l'existence de plusieurs plis avec des séries normales et renversées bien préservées. La définition et la datation de ces formations, ainsi que leur identification dans la-Zone- Houillère avoisinante permettent de mieux comprendre la géométrie initiale et les relations tectoniques des nappes du Pennique moyen dans la vallée de Zermatt. Summary This study investigates the overturned limb of the Siviez-Mischabel nappe and underlying tectonic units (Upper Stalden zone and Houillère zone) in the Mattertal area. Detailed structural analysis in the Permian Randa granite (augen orthogneiss) allows a better understanding of the Alpine deformation effects on basement rocks. Detailed mapping of this orthogneiss and surrounding rocks, and the study of the lithostratigraphy in the related sedimentary horizons allow the proposition of a structural and kinematic model for the overturned limb of the Siviez-Mischabel and to better understand the relations with the underlying tectonic units. The structural analysis of the Randa orthogneiss and surrounding rocks revealed the superposition of several phases of ductile deformation. This orthogneiss formed under greenschist facies metamorphic conditions displays a strong Alpine foliation with at least two stretching lineations. The first lineation, L1, is oriented NW-SE and is related to the nappe emplacement northward. The second one, L2, is related to the Simplon ductile shear zone. Strain estimation using the Fry method has been performed on porphyritic facies of the Randa orthogneiss. The obtained ellipses have axial ratios varying between 1.9 and 5.3, in agreement with strain estimation obtained from other markers (stretched turmalines, fringes). The strain values are very similar if measured parallel to L1 or to L2. A theoretical approach was necessary to verify the relevant application of the Fry method to augen orthogneiss. This method requires that the distribution of the used markers has to be homogeneous and isotropic. Statistical tests have been done and revealed that K-feldspar phenocrysts satisfy these conditions and can be used as strain markers with the Fry method. The obtained strain measurements revealed the importance of the Simplon ductile shear zone on the geometry of the nappe in the studied area. Mapping has improved the lithostratigraphy at the base of the Siviez-Mischabel nappe. Three overturned formations can be observed below the gneisses forming the core of the nappe. These three formations form the St-Niklaus syncline, which connects the Siviez-Mischabel nappe to the underlying Upper Stalden zone. U-Pb dating of detrital and magmatic zircons by LA-ICPMS allowed the age of the observed formations to be constrained (presumably Carboniferous to Early Triassic). This data has critical implications for nappe structure in the region, composed of few recumbent folds with well preserved normal and overturned limbs. The definition and dating of these formations, as well as their identification in the adjacent "Houillère Zone" improve the understanding of the geometry and tectonic relations of the Middle Penninic nappes in the Mattertal

    Lectotype Designation And Redescription Of Aleochara verberans

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    Volume: 97Start Page: 115End Page: 11

    The Fry method applied to an augen orthogneiss: Problems and results

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    The application of the Fry method to measure strain in deformed porphyritic granites is discussed. This method requires that the distribution of markers has to satisfy at least two conditions. It has to be homogeneous and isotropic. Statistics on point distribution with the help of a Morishita diagram can easily test homogeneity. Isotropy can be checked with a cumulative histogram of angles between points. Application of these tests to undeformed (Mte Capanne granite, Elba) and to deformed (Randa orthogneiss, Alps of Switzerland) porphyritic granite reveals that their K-feldspars phenocrysts both satisfy these conditions and can be used as strain markers with the Fry method. Other problems are also examined. One is the possible distribution of deformation on discrete shear-bands. Providing several tests are met, we conclude that the Fry method can be used to estimate strain in deformed porphyritic granites. (c) 2006 Elsevier Ltd. All rights reserved

    Water-assisted migmatization of metagraywackes in a Variscan shear-zone, Aiguilles-Rouges massif, western Alps

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    Migmatitic rocks developed in metagraywackes during the Variscan orogeny in the Aiguilles-RougesMassif (westernAlps). Partial melting took place 320 Ma ago in a 500 m-wide vertical shearzone. Three leucosome types have been recognised on the basis of size and morphology: (1) large leucosomes &gt; 2 cm wide and &gt; 40 cm long lacking mafic selvage, but containing cm-scale mafic enclaves; (2) same as 1 but with thick mafic selvage (melanosome); (3) small leucosomes &lt; 2 cm and &lt; 40 cm) with thin dark selvages (stromatic migmatites). Types 1 + 2 have mineralogical and chemical compositions in keeping with partial melting experiments. But Type 3 leucosomes have identical plagioclase composition (An19-28) to neighbouring mesosome, both in terms of major- and trace-elements. Moreover, whole-rock REE concentrations in Type 3 leucosomes are only slightly lower than those in the mesosomes, unlike predicted by partial melting experiments. The main chemical differences between all leucosome types can be related to the coupled effect of melt segregation and late chemical reequilibration. Mineral assemblages and thermodynamic modelling on bulk-rock composition restrict partial melting to ∼ 650 °C at 400 MPa. The large volume of leucosome (20 vol.%) thus generated requires addition of 1 wt.% external water. Restriction of extensive migmatization to the shearzone, without melting of neighbouring metapelites, also points to external fluid circulation within the shearzone as the cause of melting

    Production of Olefins and Higher Hydrocarbons by Thermal Coupling of Methane

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    Thermal coupling of methane or methane pyrolysis, which is a possible way for the direct chemical conversion of natural gas, can be used to produce ethylene, acetylene and benzene. But the high stability of methane requires a very high pyrolysis temperature (1200°C). To perform this reaction, IFP decided to build and elecric pilot furnace with an overall capacity of 10 m3/h. The design of this furnace is based on shell-and-tube heat exchanger technology with the use of new materials such as ceramics. This furnace has now been operating for more than one year without any noteworthy incident. First we will describe the technological and parametric study that has now been completed. In conclusion, we will make a short economic assessment of the production of ethylene and acetylene in France
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