Coimbra, Portugal
Coimbra, Portugal
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Serra A.T.,New University of Lisbon | Seabra I.J.,CIEPQPF | Seabra I.J.,Polytechnic Institute of Coimbra | Braga M.E.M.,CIEPQPF | And 6 more authors.
Journal of Supercritical Fluids | Year: 2010

In the recent years many studies on cherries revealed that they are rich sources of bioactive compounds with beneficial biological activity. In this work, fractioned high pressure extractions were performed on a traditional sweet cherry variety from Portugal ("Saco") in order to recover natural ingredients with bioactivity. The methodology employed comprised a first step with supercritical CO2 followed by a second step where different mixtures of CO2 and ethanol (10-100%, v/v) were tested. All extractions were performed at 50 °C and 25 MPa during 1 plus 1.5 h and the resulting extracts were then characterized in terms of global yield, phenolic content, antioxidant activity and screened for the presence of perillyl alcohol, a powerful anticancer compound. Moreover, cell-based assays were also performed as preliminary evaluation of potential antiproliferative activity of the cherry extracts. In the first step, lower yields were obtained and the extracts presented lower phenolic and antioxidant activity than those recovered in the second step. The extract obtained with CO2:EtOH (90:10, v/v) exhibited the highest antioxidant activity (181.4 ± 23.7 μmol TEAC/g) and was the most effective in inhibiting the growth of human colon cancer cells (ED5096h = 0.20 ± 0.02 mg/mL). Perillyl alcohol was pointed to be one of the major responsible for antiproliferative properties of cherry extracts as it was detected in the most promising products, and polyphenols, in particular sakuranetin and sakuranin, seemed to be the major contributors of the antioxidant capacity. © 2010 Elsevier B.V. All rights reserved.

Ferreira L.,ICIST | Barata I.,CIEPQPF | Costa H.,Polytechnic Institute of Coimbra | Julio E.,University of Lisbon | And 2 more authors.
fib Symposium 2012: Concrete Structures for Sustainable Community - Proceedings | Year: 2012

Alkali-activated (AA) binders can be an interesting alternative to Ordinary Portland Cement (OPC) in the scope of sustainable construction. The study herein described aimed to develop AA mortars using fly ash. First, the composition of the adopted fly ash was determined. Then different types and dosages of alkali activators, mixture proportions and curing conditions were studied. Finally both consistency and compressive strength were characterized. Results show that the AA binders, fly ash based, perform better considering an OPC addition.

Costa V.P.,CIEPQPF | Braga M.E.M.,CIEPQPF | Duarte C.M.M.,Nutraceuticals and Delivery Laboratory | Alvarez-Lorenzo C.,University of Santiago de Compostela | And 3 more authors.
Journal of Supercritical Fluids | Year: 2010

Post-processing drug impregnation of commercially available polymer-based devices is a recent and attractive approach for the development of multifunctional biomedical devices and implants, drug release systems and tissue scaffolds. Therapeutic ophthalmic articles, such as drug-loaded contact lenses, are already known to improve ocular bioavailability in the treatment of several eye diseases, namely glaucoma, as well as to minimize undesired systemic side-effects. In this work, commercial silicone-based hydrogel contact lenses (Balafilcon A) were impregnated with two anti-glaucoma drugs (acetazolamide and timolol maleate) using a discontinuous supercritical solvent impregnation (SSI) methodology. Pressure and temperature, as well as impregnation time and depressurization rate, were kept constant (17 MPa, 40 °C, 90 min, 0.06 MPa/min, respectively) in order to evaluate the effects of nature and concentration of cosolvents (ethanol and water at 5, 10 and 15% molar) on the impregnation efficiencies and the properties of the contact lenses. Glass-transition temperature (DSC), oxygen permeability, contact angle, apparent morphological changes (SEM) and in vitro drug release kinetics were studied in detail. Results demonstrated the feasibility of preparing acetazolamide and timolol maleate impregnated therapeutic Balafilcon A contact lenses using CO2 + EtOH and CO2 + H2O solvent mixtures. Valuable information about how the nature and the composition of the employed solvent mixtures influence drug loading, drug release profiles and contact lenses physical and thermomechanical properties was obtained. © 2010 Elsevier B.V. All rights reserved.

Martins R.C.,CIEPQPF | Silva A.M.T.,Centro Empresarial e Tecnologico | Castro-Silva S.,Centro Empresarial e Tecnologico | Garcao-Nunes P.,Centro Empresarial e Tecnologico | Quinta-Ferreira R.M.,CIEPQPF
Environmental Technology | Year: 2011

Ozonation, catalytic ozonation, Fenton's and heterogeneous Fenton-like processes were investigated as possible pretreatments of a low biodegradable and highly toxic wastewater produced by a detergent industry. The presence of a Mn-Ce-O catalyst in ozonation enhances the biodegradability and improves the degradation at low pH values. However, a high content of carbonyl compounds adsorbed on the recovered solid indicates some limitations for real-scale application. A commercial Fe2O3-MnOx catalyst shows higher activity as well as higher stability concerning carbon adsorption, but the leaching of metals is larger than for Mn-Ce-O. Regarding the heterogeneous Fenton-like route with an Fe-Ce-O catalyst, even though a high activity and stability are attained, the intermediates are less biodegradable than the original compounds, indicating that the resulting effluent cannot be conducted to an activated sludge post-treatment. The highest enhancement of effluent biodegradability is obtained with the classic homogeneous Fenton's process, with the BOD5/COD ratio increasing from 0.32 to 0.80. This process was scaled up and the treated effluent is now safely directed to a municipal wastewater treatment plant. © 2011 Taylor & Francis.

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