975 resultados para METAL-COMPLEXES


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A highly Al-resistant dissimilatory sulphatereducing bacteria community was isolated from sludge of the wetland of Urgeiriça mine (community W). This community showed excellent sulphate removal at the presence of Al3+. After 27 days of incubation, 73,86 and 81% of sulphate was removed in the presence of 0.48, 0.90 and 1.30 mM of Al3+, respectively. Moreover,Al3+ was simultaneously removed: 55,85 and 78% of metal was removed in the presence of 0.48, 0.90 and 1.30 mM of Al3+, respectively. The dissociation of aluminiumlactate soluble complexes due to lactate consumption by dissimilatory sulphate-reducing bacteria can be responsible for aluminum removal, which probably precipitates as insoluble aluminium hydroxide. Phylogenetic analysis of 16S rRNA gene showed that this community was mainly composed by bacteria closely related to Desulfovibrio desulfuricans. However, bacteria affiliated to Proteus and Ralstonia were also present in the community.

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Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica

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Inorganic Chemistry 50(21):10600-7

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J Biol Inorg Chem (2011) 16:1255–1268 DOI 10.1007/s00775-011-0813-8

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J Biol Inorg Chem (2008) 13:1185–1195 DOI 10.1007/s00775-008-0414-3

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Dissertation presented to Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa for obtaining the master degree in Membrane Engineering

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Dissertação para obtenção do Grau de Doutor em Engenharia Química

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This paper reports an unusual pattern of serological HBV markers and the presence of HBsAg/anti-HBs immune complexes in serum samples from two patients with fulminant hepatitis from the Brazilian Western Amazon Basin. The diagnosis was made by both serologic tests and demonstration of antigen/antibody complexes by transmission electron microscopy. Concurrent Delta virus superinfection is also discussed.

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Dissertação para obtenção do Grau de Doutor em Química Sustentável

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Ce texte essaie d’interpréter les relations qui s’établissent entre les processus de construction/négociation des identités culturelles et les processus de touristification de l’espace des villes. Les dynamiques culturelles associées au tourisme intègrent des représentations dont la forme convoque, très souvent, les concepts d’authenticité et d’hyperréalité. L’espace des villes devenues des pôles touristiques est lui aussi souvent marqué par ces deux formes culturelles. C’est, comme ce texte essaie de le montrer, le cas de Macao : le Centre Historique (« Patrimoine Mondial »), un réseau de musées (une vingtaine) et un réseau de casinos (une trentaine) constituent les éléments soumis à cette logique de production de l’espace urbain. Les formes culturelles en question – formulées, dans la théorie, comme deux formes indépendantes (et même incompatibles) – coexistent ici dans une réalité culturelle et urbaine complexe et très instable. Son interprétation exige des formes d’abordages nouvelles qui convoquent – en même temps - plusieurs échelles spatiales.

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Dissertação para obtenção do Grau de Mestre em Tecnologia e Segurança Alimentar

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The growing demand for materials and devices with new functionalities led to the increased inter-est in the field of nanomaterials and nanotechnologies. Nanoparticles, not only present a reduced size as well as high reactivity, which allows the development of electronic and electrochemical devices with exclusive properties, when compared with thin films. This dissertation aims to explore the development of several nanostructured metal oxides by sol-vothermal synthesis and its application in different electrochemical devices. Within this broad theme, this study has a specific number of objectives: a) research of the influence of the synthesis parameters to the structure and morphology of the nanoparticles; b) improvement of the perfor-mance of the electrochromic devices with the application of the nanoparticles as electrode; c) application of the nanoparticles as probes to sensing devices; and d) production of solution-pro-cessed transistors with a nanostructured metal oxide semiconductor. Regarding the results, several conclusions can be exposed. Solvothermal synthesis shows to be a very versatile method to control the growth and morphology of the nanoparticles. The electrochromic device performance is influenced by the different structures and morphologies of WO3 nanoparticles, mainly due to the surface area and conductivity of the materials. The dep-osition of the electrochromic layer by inkjet printing allows the patterning of the electrodes without wasting material and without any additional steps. Nanostructured WO3 probes were produced by electrodeposition and drop casting and applied as pH sensor and biosensor, respectively. The good performance and sensitivity of the devices is explained by the high number of electrochemical reactions occurring at the surface of the na-noparticles. GIZO nanoparticles were deposited by spin coating and used in electrolyte-gated transistors, which promotes a good interface between the semiconductor and the dielectric. The produced transistors work at low potential and with improved ON-OFF current ratio, up to 6 orders of mag-nitude. To summarize, the low temperatures used in the production of the devices are compatible with flexible substrates and additionally, the low cost of the techniques involved can be adapted for disposable devices.

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The quasi two-dimensional electron gas (q2DEG) hosted in the interface of an epitaxially grown lanthanum aluminate (LaAlO3) thin film with a TiO2-termi-nated strontium titanate (SrTiO3) substrate (001) has been massively studied in the last few years. The confinement of mobile electrons to within a few nanome-ters from the interface, superconductive behavior at low temperatures and elec-tron mobility exceeding 1000 cm2/(V.s) make this system an interesting candi-date to explore the physics of spin injection and transport. However, due to the critical thickness for conduction of 4 unit cells (uc) of LaAlO3, a high tunneling resistance hampers electrical access to the q2DEG, preventing proper injection of spin polarized current. Recently, our group found that depositing a thin overlayer of Co on LaAlO3 reduces the critical thickness, enabling conduction with only 1 uc of LaAlO3. Two scenarios arise to explain this phenomenon: a pinning of the Fermi level in the metal, inducing charge transfer in the SrTiO3; the creation of oxygen vacancies at the interface between LaAlO3 and the metal, leading to an n-type doping of the SrTiO3. In this dissertation, we will report on magnetotransport of metal/LaAlO3/SrTiO3 (metal: Ti, Ta, Co, Py, Au, Pt, Pd) heterostructures with 2 uc of LaAlO3 studied at low temperatures (2 K) and high magnetic fields (9 T). We have analyzed the transport properties of the gas, namely, the carrier concen-tration, mobility and magnetotransport regime and we will discuss the results in the light of the two scenarios mentioned above.