The transducer consists on a semiconductor device based on two stacked-i-n  heterostructures, that were designed to detect the emissions of the fluorescence resonance energy transfer between fluorophores in the cyan (470 nm) and yellow (588 nm) range of the spectrum. This research represents a preliminary study on the use of such wavelength sensitive devices as photodetectors for this kind of application. The device was characterized through optoelectronic measurements concerning spectral response measurements under different electrical and optical biasing conditions. To simulate the FRET pairs a chromatic time dependent combination of cyan and yellow wavelengths was applied to the device. The generated photocurrent was measured under reverse and forward bias to readout the output photocurrent signal. Different wavelength biasing light was also superimposed. Results show that under reverse bias the photocurrent signal presents four separate levels each one assigned to the different wavelength combinations of the FRET pairs. If a blue background is superimposed the yellow channel is enhanced and the cyan suppressed while under red irradiation the opposite behavior occurs. So under suitable biasing light the transducer is able to detect separately the cyan and yellow fluorescence pairs. An electrical model, supported by a numerical simulation supports the transduction mechanism of the device.

The transducer consists on a semiconductor device based on two stacked-i-n  heterostructures, that were designed to detect the emissions of the fluorescence resonance energy transfer between fluorophores in the cyan (470 nm) and yellow (588 nm) range of the spectrum. This research represents a preliminary study on the use of such wavelength sensitive devices as photodetectors for this kind of application. The device was characterized through optoelectronic measurements concerning spectral response measurements under different electrical and optical biasing conditions. To simulate the FRET pairs a chromatic time dependent combination of cyan and yellow wavelengths was applied to the device. The generated photocurrent was measured under reverse and forward bias to readout the output photocurrent signal. Different wavelength biasing light was also superimposed. Results show that under reverse bias the photocurrent signal presents four separate levels each one assigned to the different wavelength combinations of the FRET pairs. If a blue background is superimposed the yellow channel is enhanced and the cyan suppressed while under red irradiation the opposite behavior occurs. So under suitable biasing light the transducer is able to detect separately the cyan and yellow fluorescence pairs. An electrical model, supported by a numerical simulation supports the transduction mechanism of the device.

Abstract Extracellular- (E-PPS) and intracellular-protein– polysaccharides (I-PPS) complexes were produced by Trametes versicolor in submerged cultures with different carbon sources. The highest extracellular-(EPS) and intracellular- polysaccharide (IPS) concentration in the complexes was obtained with tomato pomace culture. DPPH radical scavenging for E-PPS and I-PPS produced by liter of culture was equivallent to 2.115 ± 0.227 and 1.374 ± 0.364 g of ascorbic acid, respectively. These complexes showed a protector effect in the oxidation of erythrocyte membranes and had ability to inhibit the hemolysis and methemoglobin synthesis in stressed erythrocytes. These results suggest that extracellular- and intracellular- polysaccharides produced are important bioactive compounds with medicinal potential.

Abstract: Several species of mushrooms, as Pleurotus ostreatus, have been valued as edible and medicinal resources. These mushrooms may be an important source of polysaccharides with medicinal properties as antioxidant, antitumoral, antimicrobial and immunological properties. The aim of this work was to produce and to evaluate the biological properties of protein-bound polysaccharide complexes, extra intracellular (E-PPS and I-PPS), extracted from P. ostreatus cultures, using agricultural sunflower wastes as carbon source. Three main compounds in the E-PPS and four main compounds in the I-PPS were identified by SEC-UV-RI-HPLC. These complexes of P. ostreatus present no toxicity in Artemia salina cultures, after 24 h of incubation. Antioxidant properties of the complexes were evaluated by radical scavenging activity using DPPH method and lipid peroxidation inhibition capacity, determined by erythrocytes hemolysis. Additionally, E-PPS and I-PPS extracts revealed capacity to mimetize superoxide dismutase and catalase enzymatic activities. The hepatoprotector effect of E-PPS extracts in Wistar rats was evaluated by AST, ALT, ALP and γ-GT activities, showing capacity to reduce the liver damage induced by ethanol-administration. This hepatoprotective effect is equivalent to that observed by silymarin, a standard drug. Our results suggests that the extracts of E-PPS and I-PPS produced by P. ostreatus cultures, using agricultural sunflower wastes as main carbon source, can be used as an important source of bioactive compounds with potential medicinal value.

As propriedades medicinais de vários cogumelos são amplamente conhecidas, no entanto, apenas nas últimas décadas, foi possível isolar e caracterizar alguns metabolitos biologicamente activos. Os efeitos terapêuticos de alguns fungos, tais como o Trametes versicolor, são maioritariamente atribuídos ao seu conteúdo em polissacáridos. O objectivo deste trabalho é estudar as propriedades hepatoprotectoras dos complexos proteína-polissacárido, produzidos por culturas líquidas de Trametes versicolor, utilizando ratos com intoxicação aguda pelo etanol, e comparar com uma droga padrão (silimarina).

Trametes versicolor é um fungo utilizado como fonte alimentar e com propriedades medicinais conhecidas [1,2]. Em trabalhos anteriores avaliámos a produtividade de complexos proteína-polissacárido intra e extracelular (IPS e EPS) em culturas de T. versicolor utilizando várias fontes de carbono. Concluímos ser esta produção máxima no 14º dia de cultura e ser o repiso de tomate a fonte de carbono mais eficaz na quantidade de produtos, EPS e IPS, obtidos. Neste trabalho estudámos a actividade biológica dos complexos EPS e IPS depois de verificarmos não apresentarem toxicidade em culturas de Artemia salina. Investigámos a actividade antioxidante pelos métodos do DPPH, -caroteno, hemólise dos eritrócitos e formação de metahemoglobina. Estudámos também as actividades superóxido dismutase (SOD) e catalase destes complexos. Os resultados obtidos sugerem que estes extractos possuem propriedades antioxidantes, pelo que poderão ser uma importante fonte de compostos bioactivos com potencial valor medicinal. Posteriormente, procedemos à extracção e purificação dos complexos por UV/RI-HPLC utilizando uma coluna de exclusão molecular, sendo possível isolar 4 compostos nos extractos de EPS (1KDa<MM <17 KDa) e 3 compostos nos extractos IPS (1KDa<MM <100 KDa). Dado o interesse destes produtos continuamos os estudos da sua bioactividade.

The easel paintings emerged in the middle ages and since then have been one of the most important art expressions. These paintings are complex systems, with a chemical compositions that change with time, depending on several factors such as the technique followed by the artist; the interaction between pigments and binders; and finally the conservation practices. However the degradation of the original materials, co-presence of different proteins, environmental contamination and precedent addition of restoring materials make this a particularly difficult task to be accomplished. The aim of this work is the characterisation and purification of four animal glues (rabbit, rabbit fur, sheepskin and fish) that are commonly used as binders in easel paintings. In order to complement the glues characterisation were used spectroscopy techniques like FTIR-ATR and µ-Raman; chromatographic techniques namely ion exchange chromatography (IEC) and size exclusion chromatography (SEC); and native PAGE. To determine the organic content, the glues were analysed in terms of proteins, polysaccharides and lipid content.