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Mesquita D.P.,IBB Institute for Biotechnology And Bioengineering | Dias O.,IBB Institute for Biotechnology And Bioengineering | Elias R.A.V.,Instituto Polytechnic Of Bragana | Amaral A.L.,IBB Institute for Biotechnology And Bioengineering | And 2 more authors.
Microscopy and Microanalysis | Year: 2010

The properties of activated sludge systems can be characterized using image analysis procedures. When these systems operate with high biomass content, accurate sludge characterization requires samples to be diluted. Selection of the best image acquisition magnification is directly related to the amount of biomass screened. The aim of the present study was to survey the effects of dilution and magnification on the assessment of aggregated and filamentous bacterial content and structure using image analysis procedures. Assessments of biomass content and structure were affected by dilutions. Therefore, the correct operating dilution requires careful consideration. Moreover, the acquisition methodology comprising a 100 × magnification allowed data on aggregated and filamentous biomass to be determined and smaller aggregates to be identified and characterized, without affecting the accuracy of lower magnifications regarding biomass representativeness. © Microscopy Society of America 2010. Source

Pereira O.R.,Polytechnic Institute of Coimbra | Silva A.M.S.,University of Aveiro | Domingues M.R.M.,University of Aveiro | Cardoso S.M.,Polytechnic Institute of Coimbra | Cardoso S.M.,Instituto Polytechnic Of Bragana
Food Chemistry | Year: 2012

The phenolic composition of the ethanolic extract obtained from the flowers of the medicinal plant Cytisus multiflorus has been elucidated by high performance liquid chromatography, electrospray mass spectrometry and nuclear magnetic resonance analysis. The extract was mainly composed of flavones, including the common chrysin, orientin, luteolin-5-O-glucoside, luteolin-7-O-glucoside, apigenin and apigenin-7-O-glucoside, which appeared as minor components. The major flavone in the extract was chrysin-7-O-β-d- glucopyranoside, and it also contained moderate amounts of a dihydroxyflavone isomer of chrysin, as well as of 2″-O-pentosyl-6-C-hexosyl-luteolin, 2″-O-pentosyl-8-C-hexosyl-luteolin and 6″-O-(3-hydroxy-3- methylglutaroyl)-2″-O-pentosyl-C-hexosyl-apigenin, which are not commonly found in the Fabaceae family. Other novel phenolic compounds found in the ethanolic extract of C. multiflorus comprised the flavones 2″-O-pentosyl- 6-C-hexosyl-apigenin, 2″-O-pentosyl-8-C-hexosyl-apigenin and 6″-O-(3-hydroxy-3-methylglutaroyl)-2″-O-pentosyl-C-hexosyl-luteolin. The assessment of the biological activities of the main compounds of this extract are now keen, in order to determine their relevance in the beneficial properties of the plant. © 2011 Elsevier Ltd. All rights reserved. Source

Dias L.G.,Instituto Polytechnic Of Bragana | Peres A.M.,Instituto Polytechnic Of Bragana | Peres A.M.,Polytechnic Institute of Coimbra | Barcelos T.P.,Instituto Polytechnic Of Bragana | And 2 more authors.
Sensors and Actuators, B: Chemical | Year: 2011

A potentiometric electronic tongue with 36 cross-sensibility lipo/polymeric membranes was built and applied for semi-quantitative and quantitative analysis of non-alcoholic beverages. A total of 16 commercial fruit juices (e.g., orange, pineapple, mango and peach) from five different brands were studied. In the semi-quantitative approach, the signal profiles recorded by the device were used together with a stepwise linear discriminant analysis to differentiate four beverage groups with different fruit juice contents: >30%, 14-30%, 6-10% and <4%. The model, with two discriminant functions based on the signals of only four polymeric membranes, explained 99% of the total variability of experimental data and was able to classify the studied samples into the correct group with an overall sensibility and specificity of 100% for the original data, and greater than 93% for the cross-validation procedure. The signals were also used to obtain MLR and PLS calibration models to estimate and predict the concentrations of fructose and glucose in the soft drinks. The linear models established were based on the signals recorded by 16 polymeric membranes and were able to estimate and predict satisfactorily (cross-validation) the concentrations of the two sugars (R2 greater than 0.96 and 0.84, respectively). © 2010 Elsevier B.V. All rights reserved. Source

Peres A.M.,Polytechnic Institute of Coimbra | Peres A.M.,Instituto Polytechnic Of Bragana | Dias L.G.,Instituto Polytechnic Of Bragana | Veloso A.C.A.,IBB Institute for Biotechnology And Bioengineering | And 4 more authors.
Talanta | Year: 2011

An all-solid-state potentiometric electronic tongue with 36 polymeric membranes has been used for the first time to detect gliadins, which are primarily responsible for gluten intolerance in people suffering from celiac disease. A linear discriminant model, based on the signals of 11 polymeric membranes, selected from the 36 above using a stepwise procedure, was used to semi-quantitatively classify samples of a "Gluten-free" foodstuff (baby milked flour), previously contaminated with known amounts of gliadins (<10, 20-50 or >50 mg/kg), as "Gluten-free", "Low-Gluten content" or "Gluten-containing". For this food matrix, the device had sensitivity towards gliadins of 1-2 mg/kg and overall sensitivity and specificity of 77% and 78%, respectively. Moreover, the device never identified an ethanolic extract containing gliadins as "Gluten-free". Finally, the system also allowed distinguishing "Gluten-free" and "Gluten-containing" foodstuffs (15 foods, including breads, flours, baby milked flours, cookies and breakfast cereals) with an overall sensitivity and specificity greater than 83%, using the signals of only 4 selected polymeric membranes (selected using a stepwise procedure). Since only one "Gluten-containing" foodstuff was misclassified as "Gluten-free", the device could be used as a preliminary tool for quality control of foods for celiac patients. © 2010 Elsevier B.V. All rights reserved. Source

Abreu R.M.V.,Instituto Polytechnic Of Bragana | Abreu R.M.V.,University of Tras os Montes e Alto Douro | Ferreira I.C.F.R.,Instituto Polytechnic Of Bragana | Calhelha R.C.,Instituto Polytechnic Of Bragana | And 6 more authors.
European Journal of Medicinal Chemistry | Year: 2011

Hepatocellular carcinoma (HCC) is a highly complex cancer, resistant to commonly used treatments and new therapeutic agents are urgently needed. A total of thirty-two thieno[3,2-b]pyridine derivatives of two series: methyl 3-amino-6-(hetero)arylthieno[3,2-b]pyridine-2-carboxylates (1a-1t) and methyl 3-amino-6-[(hetero)arylethynyl]thieno[3,2-b]pyridine-2-carboxylates (2a-2n), previously prepared by some of us, were evaluated as new potential anti-HCC agents by studying their in vitro cell growth inhibition on human HepG2 cells and hepatotoxicity using a porcine liver primary cell culture (PLP1). The presence of amino groups linked to a benzene moiety emerges as the key element for the anti-HCC activity. The methyl 3-amino-6-[(3-aminophenyl)ethynyl] thieno[3,2-b]pyridine-2-carboxylate (2f) is the most potent compound presenting GI50 values on HepG2 cells of 1.2 μM compared to 2.9 μM of the positive control ellipticine, with no observed hepatotoxicity (PLP1 GI 50 > 125 μM against 3.3 μM of ellipticine). Moreover this compound changes the cell cycle profile of the HepG2 cells, causing a decrease in the % of cells in the S phase and a cell cycle arrest in the G2/M phase. QSAR studies were also performed and the correlations obtained using molecular and 1D descriptors revealed the importance of the presence of amino groups and hydrogen bond donors for anti-HCC activity, and hydrogen bond acceptors for hepatotoxicity. The best correlations were obtained with 3D descriptors belonging to different subcategories for anti-HCC activity and hepatotoxicity, respectively. These results point to different molecular mechanisms of action of the compounds in anti-HCC activity and hepatotoxicity. This work presents some promising thieno[3,2-b]pyridine derivatives for potential use in the therapy of HCC. These compounds can also be used as scaffolds for further synthesis of more potent analogs. © 2011 Elsevier Masson SAS. All rights reserved. Source

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