Browsing by Author "Pereira, J."
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- Localized density measurements on ASDEX using microwave reflectometryPublication . Manso, M.E.; Serra, F.; Silva, A.; Matias, José; Nunes, F.; Leitão, J.; Mata, J.; Varela, P.; Vergamota, S.; Neves, J.; Pereira, J.; Cupido, L.; Soldner, F.X.; Siller, G.Reflectometry is based on the propagation and reflection of probing waves in the inhomogeneous fusion plasma.
- Studies on sorption and regeneration of granulated cork for oil and grease removalPublication . Pereira, J.; Ferreira, Catarina Isabel de Almeida; Pintor, Ariana; Correia, P.; Silva, Susana; Vilar, Vítor J.P.; Botelho, Cidália; Martins, Ramiro; Órfão, J.; Boaventura, RuiThe aim of this work is to develop a method to recover sorbed oil and grease from granulated cork, in order to promote biomass regeneration. Experimental procedure involved biomass saturation with oil, followed by chemical regeneration. Oil removal by elution was tested using HNO3 and NaOH solutions, cationic and anionic surfactants and organic solvents, namely carbon tetrachloride and n-hexane. Chemical desorption efficiency using organic solvents achieved values of 90 ± 6 % and 72 ± 6 % for CCl4 and n-hexane, respectively. Although the use of organic solvents proved to be an efficient process, it involves high costs and a negative environmental impact. Physical regeneration could be an alternative to the use of solvents for oil removal from granulated cork.
- Study of the cell growth inhibitory effect of aqueous extracts from Tuberaria lignosa in human tumor cell linesPublication . Pereira, J.; Rodrigues, V.L.; Lima, M. João; Lima, Raquel T.; Ferreira, Isabel C.F.R.; Vasconcelos, M. HelenaTuberaria lignosa (Sweet) Samp. (“alcária”), a plant mostly found in Western regions of the Iberian Peninsula, has antioxidant properties due to its composition in ascorbic acid and phenolic compounds [1]. Given these antioxidant properties, together with the traditional use of the plant to treat several diseases, the aims of this work were to: i) investigate if aqueous extracts from this plant, obtained by infusion and decoction, were inhibitors of cell growth in three human tumor cell lines; ii) study the cellular mechanism of action of the most potent extract. A screening of tumor cell growth inhibitory potential was performed with the Sulforhodamine B (SRB) assay using three different human tumor cell lines: MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and HCT-15 (colorectal adenocarcinoma). Results showed that both aqueous extracts of T. lignosa decreased the growth of the cell lines tested and that the T. lignosa infusion extract was the most potent one, particularly in the NCI-H460 and HCT-15 cells. The T. lignosa infusion extract was further tested in the NCI-H460 cells. A determination of its effect on cell cycle profile was carried out, by analyzing cellular DNA content by flow cytometry following incubation with propidium iodide. Determination of cellular apoptosis was also performed, with the Annexin V-FICT and propidium iodide assay, and analyzed by flow cytometry. Preliminary results showed that the selected extract promoted a slight increase in the percentage of cells in the G1 phase of the cell cycle and induced cellular apoptosis. In conclusion, the T. lignosa extract decreased growth of the human tumor cell lines tested and the most potent effect was observed for the T. lignosa infusion extract. Future work will confirm if this effect is due mainly to induction of apoptosis.
- Treatment of wastewater containing mineral oil by sorption onto granulated corkPublication . Ferreira, Catarina Isabel de Almeida; Pereira, J.; Pintor, Ariana; Correia, P.; Silva, J.; Vilar, Vítor J.P.; Botelho, Cidália; Martins, Ramiro; Orfão, J.; Boaventura, RuiThe aim of this work is the development of a new method to remove oils from wastewaters, namely hydrocarbons. These contaminants, when present in high concentrations, are efficiently removed by physical and chemical processes, such as gravity separators, flocculation and flotation processes; however for low concentrations, these methods are not applicable [1]. Moreover, advanced separation processes such as membrane separation [2] and activated carbon adsorption [3] are expensive options for the treatment of oil-containing wastewaters. This new technique is based on oil and hydrocarbons’ sorption on cork granules.
- Utilização de resíduos ou subprodutos de cortiça para a eliminação de óleos e gorduras de águas.Publication . Vilar, Vítor J.P.; Ferreira, Catarina Isabel de Almeida; Pereira, J.; Pintor, Ariana; Botelho, Cidália; Martins, Ramiro; Órfão, J.; Boaventura, Rui; Correia, P.; Silva, S.Este trabalho pretende apresentar a cortiça como um material competitivo para a resolução de problemas ambientais, nomeadamente a eliminação de gorduras hidro-solúveis ou dispersas em águas. Os métodos convencionais de tratamento, que incluem processos físicos/químicos, são muito eficientes na remoção de óleos e gorduras em concentrações elevadas, mas são ineficazes quando estes poluentes estão presentes em baixas concentrações, sendo necessário utilizar tecnologias dispendiosas de separação por membranas ou adsorção em carvão ativado. Nesse sentido, pretende-se encontrar um material de cortiça adequado, tendo em conta uma ampla diversidade de fontes e granulometrias, para esta aplicação, com o intuito de obter um efluente final com a qualidade exigível para a reutilização da água, reduzindo os custos associados ao consumo de água e taxas de descarga do efluente no emissário ou no meio hídrico natural, sem falar do benefício ambiental decorrente da redução de consumo de água pelas indústrias que utilizem esta tecnologia.