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Browsing by Author "Barrocas Dias, Cristina"

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  • Magnetite nanoparticles functionalized with propolis against methicillin resistant strains of Staphylococcus aureus
    Publication . EL-GEUNDOUZ, Soukaina; Lyoussi, Badiaa; Lourenço, João P.; Rosa Da Costa, Ana; Miguel, Maria; Barrocas Dias, Cristina; Manhita, Ana; Jordao, Luisa; Nogueira, Isabel; Faleiro, Maria Leonor
    Magnetite nanoparticles (MNPs) have been evaluated for inhibiting microbial growth and biofilm formation. In this study the effect of the nanocomposite Moroccan propolis extract / MNPs acting against methicillin resistant strains of Staphylococcus aureus (MRSA) was evaluated. Chemical composition of propolis was established by pyrolysis coupled to gas chromatography and mass spectrometry method (pyrolysis GC/MS). MNPs were obtained through the co-precipitation method. The fabricated nanostructure was characterized by X-ray Diffraction (DRX), Transmission Electron Microscopy (TEM), and Fourier Transform-Infrared Spectroscopy (FTIR). TEM of MNPs provided a particle average size of 15 nm, FTIR spectral analysis enabled a fast way of identification of MNPs, attesting the occurrence of the different combinations. The use of MNPs loaded with propolis and the antibiotic chloramphenicol at Minimum Inhibitory Concentration (MIC) value inhibited the bacterial growth of MSSA (methicillin susceptible strain of S. aureus) and MRSA strains. After the treatment with MNPs-OA-P-CLo nanocomposite (MNPs with oleic acid, propolis and chloramphenicol), the disruption of the bacterial cell was observed by TEM. The combination of propolis and chloramphenicol in free form at MIC value largely impaired both MSSA and MRSA strains as, after 2 h of treatment, no viable cells of MRSA 2 and MRSA 16 were recovered. Hence, the results elucidated a new antibacterial nanocomposite synthesis, for possible applications as prospective nanoantibacterial agents or drug carriers.
    2019Journal article Restricted access Show more
  • The “Ferradeira” individual burial of Herdade do Álamo (Beja): facets of social change in the late 3rd millennium BC in South Portugal
    Publication . Valera, António Carlos; do Pereiro, Tiago; Nogueira, Sofia; Evangelista, Lucy; Maurer, Anne-France; Barrocas Dias, Cristina; Ribeiro, Sara; Bottaini, Carlo
    The individual burial of the Herdade do Alamo, located in Beja municipality, South Portugal, is presented along with its bioanthropological study, radiocarbon dating and isotopic approaches on diet and mobility. The results show a male, with a terrestrial diet and youth mobility, dating from the last quarter of the 3rd millennium BC. The archaeometallurgical study of the metal votive assemblage (one tongue dagger and three Palmela points) indicates a copper metallurgy with high values of Arsenic (As), typical of this period of transition. The burial is contextualized in a process of individuation of the funerary practices and in the "Ferradeira Horizon", considered as a facet of the diversified funerary practices and of the complex social changes of the late 3rd millennium BC in the South of Portugal.
    2022Journal article Open access Show more