Browsing by Issue Date, starting with "1999-09"
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- Transport properties in microcrystalline silicon solar cells under AM1.5 illumination analysed by two-dimensional numerical simulationPublication . Fantoni, Alessandro; Vieira, Manuela; Martins, RodrigoMicrocrystalline silicon is a two-phase material. Its composition can be interpreted as a series of grains of crystalline silicon imbedded in an amorphous silicon tissue, with a high concentration of dangling bonds in the transition regions. In this paper, results for the transport properties of a mu c-Si:H p-i-n junction obtained by means of two-dimensional numerical simulation are reported. The role played by the boundary regions between the crystalline grains and the amorphous matrix is taken into account and these regions are treated similar to a heterojunction interface. The device is analysed under AM1.5 illumination and the paper outlines the influence of the local electric field at the grain boundary transition regions on the internal electric configuration of the device and on the transport mechanism within the mu c-Si:H intrinsic layer.
- Structure of Tetrahymena CCTθ gene and its expression under colchicine treatmentPublication . Domingues, Célia; Soares, Helena; Rodrigues-Pousada, Claudina; Cyrne, LuisaWe report here the cloning and the characterization of the Tetrahymena pyriformis chaperonin-containing-TCP1 theta gene (TpCCTθ), an orthologue of the mouse chaperonin gene CCTθ. TpCCTθ gene is interrupted by eight introns, ranging in size between 91 and 419 nucleotides, and encodes a protein consisting of 540 amino acid residues (59.1 kDa), with a putative pI of 5.73. The amino acid sequence of TpCCTθ reveals 39.4–46.0% identity with the sequences of Candida albicans and mouse CCTθ subunits and 28.0–32.6% identity with the other TpCCT subunits known so far. We have studied the expression of this gene in exponentially growing Tetrahymena cells and in cells treated with colchicine for different times. The steady-state levels of CCTθ mRNA rapidly decrease in the first 30 min of colchicine treatment. Interestingly, treatment for subsequent 60 min gives expression levels higher than those found in exponentially growing cells.
- O caso do projecto de eliminação de resíduos industriais pelo sector cimenteiro: relatório de episódios de conflito ambiental: relatório finalPublication . Subtil, Filipa Mónica de Brito Gonçalves; Ferreira, José GomesNo âmbito da investigação dos Episódios de Conflito Ambiental a presente equipa tem, ao longo dos últimos meses, centrado a sua atenção no conflito ambiental provocado pela mudança de estratégia, por parte do XIII governo Constitucional presidido pelo Eng. António Guterres, na gestão dos resíduos industriais perigosos. Na orientação do governo houve uma intenção deliberada de realizar um conjunto de medidas de carácter curativo para fazer face ao grave problema do passivo ambiental e dos riscos possíveis para a saúde pública provocados pelo despejo anárquico de resíduos, aspecto que tem caracterizado a paisagem industrial do nosso país nas últimas décadas. Na mesma óptica, não foram apresentadas medidas de carácter preventivo, de modo a evitar que a situação de degradação ambiental acabe por ter de ser equacionada mais tarde.