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| Registros recuperados: 35 | |
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| Rodrigues, M.A.; Lopes, João; Pavão, Francisco; Cabanas, J.E.; Arrobas, Margarida; Abreu, Rui M.V.; Correia, Carlos; Moutinho-Pereira, José. |
| Currently, in NE Portugal, we are advising farmers to adopt ground-cover systems in olive orchards instead of tillage. Most of soils are on steep slopes and have very low organic matter content (Arrobas and Rodrigues, 2002). This consequently creates huge problems for soil conservation. However, we need strong arguments to convince the farmers. Tillage in a very old and ingrained practice; it is easy, pleasant and in some ways it works. Alternative management systems, such as the use of herbicides or cover crops, need a high degree of technical expertise. Ground-cover systems affect crop growth and yields by influencing weed competition, water use efficiency, nutrient uptake, soil fertility and soil conservation. In order to evaluate the multiple aspects... |
| Tipo: Article |
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| Ano: 2006 |
URL: http://hdl.handle.net/10198/3135 |
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| Ferreira, Isabel C.F.R.; Abreu, Rui M.V.. |
| A manutenção do equilíbrio entre a produção de radicais livres e as defesas antioxidantes (enzimas e moléculas não enzimáticas) é uma condição essencial para o funcionamento normal do organismo. Quando este equilíbrio tende para a produção de radicais livres dizemos que o organismo está em stress oxidativo, e nestas situações os radicais livres em excesso podem oxidar e danificar lípidos celulares, proteínas e DNA, inibindo a sua função normal e conduzindo a várias doenças. Em organismos aeróbios, os radicais livres são constantemente produzidos durante o funcionamento normal da célula, na maior parte sob a forma de espécies reactivas de oxigénio (ROS) e de nitrogénio (RNS). A exposição dos organismos a radicais livres, conduziu ao desenvolvimento de... |
| Tipo: Article |
Palavras-chave: Stress oxidativo; Antioxidantes; Fitoquímicos; Oxidative stress; Antioxidants; Phytochemicals. |
| Ano: 2007 |
URL: http://hdl.handle.net/10198/2711 |
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| Abreu, Rui M.V.; Falcão, Soraia; Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.; Vilas-Boas, Miguel. |
| Cyclic voltammetry was used to evaluate the antioxidant activity of 7-aryl or 7-heteroarylamino-2,3-dimethylbenzo[b]thiophenes previously synthesized by some of us, comparing their oxidation potentials with those of the well-known synthetic standards (BHA, BHT). Compounds with electron-donating groups on the arylamine moiety have lower Ep/2 than compounds with electron-withdrawing groups or electron-deficient rings (pyridines). The position of the methoxy group on the arylamine moiety also changes the oxidation potential: lower Ep/2 for the diarylamines with methoxy groups in the para position. Comparing the first peak potential with the ones of BHA and BHT, the diarylamine compounds show lower oxidation potential, and therefore higher reducing power. A... |
| Tipo: Article |
Palavras-chave: Benzo[b]thiophene; Diarylamines; Antioxidant properties; Electrochemical assays. |
| Ano: 2009 |
URL: http://hdl.handle.net/10198/2717 |
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| Ferreira, Isabel C.F.R.; Barros, Lillian; Abreu, Rui M.V.. |
| Maintenance of equilibrium between free radical production and antioxidant defences (enzymatic and non enzymatic) is an essential condition for normal organism functioning. When this equilibrium has a tendency for the production of free radicals we say that the organism is in oxidative stress. In this situation, excess free radicals may damage cellular lipids, proteins and DNA, affecting normal function and leading to various diseases. In aerobic organisms, the free radicals are constantly produced during the normal cellular metabolism, mainly in the form of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS). Exposition of the organism to free radicals has led to the development of endogenous defence mechanisms to eliminate them. These... |
| Tipo: Article |
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| Ano: 2009 |
URL: http://hdl.handle.net/10198/2855 |
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| Froufe, Hugo J.C.; Abreu, Rui M.V.; Ferreira, Isabel C.F.R.. |
| Wild mushrooms have been described as sources of natural antioxidants, particularly phenolic compounds. However, many other compounds present in wild mushrooms can also act as antioxidants (reducers), so whole extracts from a wide range of species need to be examined. To gain further knowledge in this area, the relationship between the antioxidant potential (scavenging effect and reducing power) and chemical composition of twenty three samples from seventeen Portuguese wild mushroom species was investigated. A wide range of analytical parameters reported by our research group (including ash, carbohydrates, proteins, fat, monounsaturated fatty acids, polyunsaturated fatty acids, saturated fatty acids, phenolics, flavonoids, ascorbic acid and -carotene)... |
| Tipo: Article |
Palavras-chave: Wild mushrooms; Chemical composition; Antioxidant activity; QCAR; PLS. |
| Ano: 2009 |
URL: http://hdl.handle.net/10198/2615 |
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| Abreu, Rui M.V.; Ferreira, Isabel C.F.R.; Queiroz, Maria João R.P.. |
| A QSAR study was developed in order to model the antioxidant activity, specifically the radical scavenger activity (RSA), of 26 di(hetero)arylamines’ derivatives of benzo[b]thiophenes. The QSAR model was constructed, using the partial least squares projection of latent structures (PLS) method, and its robustness and predictability were verified by internal and external cross-validation methods. A total of 4 molecular descriptors, belonging to RDF (Radial Distribution Function) descriptors (RDF020e and RDF045e) and 2D-autocorrelation descriptors (GATS8p and MATS5e) were selected to build the QSAR model. RDF descriptors seem to relate the presence of electronegative atoms at the inner atmosphere of the compounds to increase RSA. 2D-Autocorrelation... |
| Tipo: Article |
Palavras-chave: Benzo[b]thiophenes; Di(hetero)arylamines; Antioxidants; QSAR; PLS. |
| Ano: 2009 |
URL: http://hdl.handle.net/10198/2649 |
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| Abreu, Rui M.V.; Froufe, Hugo J.C.; Queiroz, Maria João R.P.; Ferreira, Isabel C.F.R.. |
| Background: Virtual screening of small molecules using molecular docking has become an important tool in drug discovery. However, large scale virtual screening is time demanding and usually requires dedicated computer clusters. There are a number of software tools that perform virtual screening using AutoDock4 but they require access to dedicated Linux computer clusters. Also no software is available for performing virtual screening with Vina using computer clusters. In this paper we present MOLA, an easy-to-use graphical user interface tool that automates parallel virtual screening using AutoDock4 and/or Vina in bootable non-dedicated computer clusters. Implementation: MOLA automates several tasks including: ligand preparation, parallel AutoDock4/Vina... |
| Tipo: Article |
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| Ano: 2010 |
URL: http://hdl.handle.net/10198/3040 |
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| Registros recuperados: 35 | |
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