Browsing by Author "Castro, M."
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- Biodegradation of acrylic-based reline resin monomers-effect of salivary esterasePublication . Neves, C.; Almeida, M.; Vilhena, C.; Lopes, L. P.; Castro, M.; Bettencourt, A.
- Contaminant metals in black scabbard fish (Aphanopus carbo) caught off Madeira and the AzoresPublication . Afonso, C.; Lourenco, H. M.; Dias, Abreu; Nunes, M. L.; Castro, M.Total mercury, cadmium and lead concentrations were measured in black scabbard fish (Aphanopus carbo), caught off Madeira and the Azores archipelagos (Portugal). The metal contents were expressed in mg kg(-1) wet weight. The mean mercury levels in liver were 4.50 and 2.37 whereas, in skin, such values were 0.59 and 0.36 (Madeira and Azores, respectively). Onaverage, the muscle content was around 0.9 in fish from both areas. Cadmium maximum levels in muscle and skin were found in Azores samples (0.09 and 0.11, respectively). Mean lead contents in all samples were always below than 0.10. In general, the results obtained did not allow the establishment of any relationship between metal accumulation and fish weight or length. According to the permissible WHO and FAO levels, these results, suggest that this species does not represent a risk for human consumption if the liver is excluded and the edible part consumed with moderation. (c) 2006 Elsevier Ltd. All rights reserved.
- Incorporation of tocopherol acetate-containing particles in acrylic bone cementPublication . Bettencourt, A.; Florindo, H. F.; Ferreira, I. F. S.; Matos, A.; Monteiro, J.; Neves, C.; Lopes, P.; Castro, M.; Almeida, A. J.Acrylic bone cement (BC) is used in orthopaedic surgery to anchor cemented prostheses to bone. Association of antioxidant molecules to BC may suppress reactive species injury which contributes to implant failure. Tocopherol acetate (ATA)-loaded polymethylmethacrylate (PMMA) particles (ATA(PMMA)) were prepared by single emulsion solvent evaporation technique and were incorporated into BC. An encapsulation efficiency of 84% (w/w) was obtained and drug release studies showed distinct ATA release profiles and mechanisms before and after particle incorporation into BC. Experimental data, analysed using first-order, Higuchi and Korsmeyer-Peppas models revealed that ATA was released from particles by a Fickian diffusion mechanism while a non-Fickian transport was observed upon particle incorporation in BC. There were no changes in the mechanical properties of BC specimens containing ATA(PMMA) particles, in contrast to what was observed when ATA was loaded directly into BC. Overall, ATA(PMMA) particles are potential carriers for the incorporation of an antioxidant drug into BC.
- Small ruminants as a fire management tool in a Mediterranean mountain regionPublication . Castro, M.; Fernandez-Nunez, E.Small ruminants as a fire management tool in a Mediterranean mountain region Castro M. and Fernández-Núñez E. Forests represent a key-resource for the Mediterranean region and have supplied wood and non-wood products for centuries. Socioeconomic transformations of last decades in rural areas convert these areas into bombs-clock able of blowing up every summer. Actually, Southern Europe has in last years experienced dramatic changes in the fire regime because of changes in land use. Further alterations toward more severe fire events are expected with the prospect of a warmer and drier future. Portugal has adopted some policy regulations to protect the forest, including national strategy for forests, national defense plan against forest fires. Despite improvements fire’s statistics, Portugal failed to achieve the goals it had set itself. Political options privilege fire suppression, even though land and forest management issues are at the core of the wildfire problem. Agroforestry systems can be used as a forest fire prevention technique, since they implement a fuel management network at different scales of landscape. Particularly, silvopastoral systems (SSP) are especially interesting as a fuel management tool and reducing fire risk. The objectives of this study were to compare the diet of goats and sheep in a SSP namely mosaic of different land uses within one management unit. Grazing itineraries were recorded by means of a GPS. Goats´ diet had a significantly higher content of shrubs and trees species than of sheep. Sheep showed a higher content of herbaceous species in their diets and a higher preference for stubble. Erica sp. and Rubus sp. in goats were the shrubs with the highest preference index. Both animals avoided Cytisus multiflorum in winter and spring, and Cistus ladanifer in summer.
- The impact of supercritical fluids processing on minocycline antibacterial activityPublication . Pinheiro, L.; Bettencourt, A.; Duarte, Aida; Bettencourt, K.; Almeida, António José; Castro, M.; Padrela, L.; Rodrigues, M. A.; Matos, H. A.