ES - Resumos em livros de actas
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- Alterações na actividade enzimática (GST e CAT) e histopatologia em Danio rerio após exposição a diferentes concentrações de nanodiamantePublication . Diniz, M. S.; Laugros, Hellene; Peres, Isabel; Castro, Luísa; Mendonça, E.; Picado, Ana
- Cork boiling wastewater anaerobic digestion process leads to biogas and valuable enzymes productionPublication . Gil, Luís; La Cara, F.; Marques, Isabel PaulaCork is the outer bark of the cork-tree (Quercus suber L.) and it is a very important industrial sector in western Mediterranean region, being Portugal the world-leading producer and exporter (1). The anaerobic digestion has never been applied to the treatment and valorization of the industrial cork effluents (cork boiling wastewater, CBW). The goal of the present work is evaluate the role of this biological process in providing valuable biomolecules, i.e. enzymes, during the conversion of CBW. Anaerobic experiments were conducted under mesophilic conditions of temperature and the obtained results suggest that CBW is an interesting substrate to be treated and valorised through the anaerobic digestion. Besides the energy recovery through biogas production by anaerobic digestion of CBW, the increase in the reactor effluent of valuable biomolecules is an aspect of great industrial interest. The identification and characterization of such products of high added value creates a supplementary prospect of effluent valorisation, contributing to the cork sector profits. During the CBW anaerobic digestion process several important alterations on the enzymatic capacity of the digested flow were observed. For instance, the laccase activity contained in the CBW was implemented by anaerobiosis and the xilanase was formed during the process. Laccases exhibit low substrate specificity and can be used in different industrial sectors (i.e. paper manufacturing, wine stabilization and wastewater treatment) (2). Xylanases are enzymes involved in the hydrolyse carbohydrates and are used in the pulp, paper and food industries (3). The production of enzymes with commercial interest offers an additional opportunity for the biotechnological valorisation of the CBW, contributing to make the process more interesting and cheaper.
- Charge transport and recombination of dye sensitized 1D nanostructured-TiO2 films prepared by reactive sputteringPublication . Sequeira, S.; Lobato, K.; Torres, Erica; Brites, Maria João; Barreiros, M. Alexandra; Mascarenhas, JoãoDye sensitized solar cells (DSCs) are governed by light absorption, charge injection, electron transport and recombination and electrolyte diffusion. One way to improve the efficiency of these devices is by the design of highly ordered nanostructured semiconductor materials.The advantages can be two-fold: Firstly charge transport within the metal-oxide can be enhanced and hence thicker films can be employed and secondly, the complete permeation with a solid-state hole-transport medium of the sensitized metal-oxide can be facilitated. Nanostructured materials should promote vectorial electron diffusion and have as few recombination sights as possible so as to further enhance electron lifetimes and electron collection efficiencies. These materials should also have a high surface area so as to allow for efficient dye-loading and hence light absorption. Highly ordered TiO2 nanostructured films were prepared by reactive sputtering and their charge transport characteristics evaluated in DSCs. These were compared to DSCs employing mesoporous TiO2 films prepared by doctor blade technique using commercial paste. Charge transport characteristics were evaluated by impedance spectroscopy (IS), incident photon to current conversion efficiencies (IPCE) and current-voltage (iV) curves under simulated AM1.5G irradiation. Film morphology and structural properties were evaluated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively.
- Synthesis, optical and electrochemical properties of perylenes dyes for solar cells applicationsPublication . Torres, Erica; Sequeira, S.; Berberan-Santos, Mário N.; Brites, Maria JoãoPerylene monoimides or monoanhydrides are being intensively investigated as sensitizers in DSSCs. Keeping only one acceptor group, i.e. imide or anhydride, and introducing a donor group in the 9-position (such as diarylamine) proved to be important in order to obtain a favorable orbital partitioning strength and dipole moment of perylene compounds for DSSCs [1]. One way to control optical and electrochemical properties of perylenes dyes is achieved by functionalizing periand bay positions of perylene core with different substituents. In a simplified view, the peri groups coarsely tune the spectroscopic and electrochemical properties whereas the bay functional groups provide an additional fine tuning [2,3]. Here we report the design and synthesis of new perylene dyes (Figure 1) comprising: (1) a 4-alkoxyphenylamino moiety in the 9-position as a strong donating group, (2) a cyanoacrylic acid as electron acceptor and anchoring group and (3) a triple bond as short and rigid linker between perylene core and the acceptor group [4]. The photophysical properties (i.e. absorption and emission spectra, absorption extinction coefficients, fluorescence quantum yields and lifetime measurements) and electrochemical properties of the new perylene dyes were investigated and all results will be presented and discussed.
- Low-temperature nitriding of VA-group metal powders (V,Nb,Ta) in flowing NH3 gas under heating with concentrated solar beam at PSAPublication . Fernandes, Jorge Cruz; Oliveira, Fernando Almeida Costa; Rosa, Luís Guerra; Rodríguez, José; Cañadas, Inmaculada; Magalhães, Teresa; Shohoji, NobumitsuOver the last two decades, we have been using concentrated solar beam as the reaction heat source for synthesizing carbides and nitrides of d-group transition elements in view of usage of ecological renewable energy source in place of conventional heat sources using electricity or gas. In recent works [1,2] nitriding of VIa-group metals (Cr, Mo, W) and Fe in stream of NH3 gas with suppressed extent of dissociation (uncracked NH3) was attempted under heating with concentrated solar beam. It was demonstrated that mono-nitride -MoN of Mo and sub-nitride -Fe2N of Fe that are known to be impossible to synthesize in N2 gas environment even at elevated pressure p(N2) were successfully synthesized by the reactions of these metals in stream of NH3 gas under heating with concentrated solar beam up to 800ºC. In the present work, nitriding of Va-group metals (V, Nb and Ta) was attempted in stream of NH3 gas under irradiation of concentrated solar beam. By up to 90 min heating in uncracked NH3 under concentrated solar beam up to 800ºC, reaction products were identified by X-ray diffraction (XRD) analysis to be consisted of mono-nitride MN co-existent with sub-nitride M2N.
- Cork-derived ceria ecoceramics for solar fuel production via thermochemical redox process using concentrated solar energyPublication . Novais, Rui M.; Oliveira, Fernando Almeida Costa; Barreiros, M. Alexandra; Abanades, Stéphane; Caetano, Ana P. F.; Pullar, Robert C.