Browsing by Author "Ferraz, Maria Pia"
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- A cyclam salt as an antifungal agent: Interference with Candida spp. and Cryptococcus neoformans mechanisms of virulencePublication . Cerqueira, Fátima; Medeiros, Rui; Lopes, Inês; Campos, Carla; Ferraz, Maria Pia; Silva, Fernando; Alves, Luís G.; Pinto, EugéniaThe importance of fungal infections, particularly those caused by yeasts, is increasing among the medical community. Candida albicans and Cryptococcus neoformans are amongst the high-priority fungal species identified by the World Health Organization (WHO) and are considered in the critical group, while Candida krusei is included in the medium-priority group. The cyclam salt H4[H2(4-CF3PhCH2)2Cyclam]Cl4 proved to be active against the growth of these three yeasts, and the aim of this work was to verify its interference with their virulence mechanisms, whether shared or unique. H4[H2(4-CF3PhCH2)2Cyclam]Cl4 significantly inhibited biofilm production and catalase activity, being able to interfere with C. albicans dimorphic transition and C. neoformans melanin production. At the minimal inhibitory concentration (MIC) values, H4[H2(4-CF3PhCH2)2Cyclam]Cl4 had no antioxidant effect, as determined by the DPPH method. When using the RAW264.7 macrophage cell line, H4[H2(4-CF3PhCH2)2Cyclam]Cl4 reduced nitric oxide (NO) detection (the Griess reaction), but this effect was associated with a significant toxic effect on the cells.
- Graphene nanoparticles on refractive index of cancerous breast tissues: spectral approachPublication . Martins, Inês; Ferraz, Maria Pia; Ramos, C.A.; Vilão, G.This work presents a study on the influence of graphene nanoparticles on the refractive index (RI) for application in breast tissues as an aid in the diagnosis of cancerous cells, using a spectral approach to evaluate the behaviour of glycerine and water-based nanofluids in various proportions. Glycerine-water solutions with different volumetric fractions of graphene were prepared, and the RI was measured using an Abbe refractometer. UV-Vis absorption spectra were analysed, indicating that higher volumetric fractions of graphene significantly affect light absorption and scattering patterns. This preliminary study identifies the optimal graphene volumetric fractions for future analyses of light-tissue interaction, aiming to improve diagnostic methods and characterisation of cancerous tissues through light scattering.