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Candida albicans is the most common fungal pathogen in humans, and recently some studies have reported the antifungal activity of silver nanoparticles (AgNPs) against some Candida species. However, ultrastructural analyses on the interaction of AgNPs with these microorganisms have not been reported. In this work we evaluated the effect of AgNPs on C. albicans, and the minimum inhibitory concentration (MIC) was found to have a fungicidal effect. The IC50 was also determined, and the use of AgNPs with fluconazole (FLC), a fungistatic drug, reduced cell proliferation. In order to understand how AgNPs interact with living cells, the ultrastructural distribution of AgNPs in this fungus was determined. Transmission electron microscopy (TEM) analysis revealed a high accumulation of AgNPs outside the cells but also smaller nanoparticles (NPs) localized throughout the cytoplasm. Energy dispersive spectroscopy (EDS) analysis confirmed the presence of intracellular silver. From our results it is assumed that AgNPs used in this study do not penetrate the cell, but instead release silver ions that infiltrate into the cell leading to the formation of NPs through reduction by organic compounds present in the cell wall and cytoplasm.

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Au has been loaded (1% wt.) on different commercial oxide supports (CuO, La 2 O 3 , Y 2 O 3 , NiO) by three different methods: double impregnation (DIM), liquid-phase reductive deposition (LPRD), and ultrasonication (US). Samples were characterised by N 2 adsorption at -196 °C , high-resolution transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray spectrometry, high-angle annular dark-field imaging (Z-contrast), X-ray diffraction, and temperature programmed reduction. CO oxidation was used as a test reaction to compare the catalytic activities. The best results were obtained with Au loaded by DIM on the NiO support, with an activity of 7.2 × 10 -4 mol CO· g Au -1 · s -1 at room temperature. This is most likely related to the Au nanoparticle size being the smallest in this catalyst (average 4.8 nm), since it is well known that gold particle size determines the catalytic activity. Other samples, having larger Au particle sizes (in the 2-12 nm range, with average sizes ranging from 4.8 to 6.8 nm), showed lower activities. Nevertheless, all samples prepared by DIM had activities (from 1.1 × 10 -4 to 7.2 × 10 -4 mol CO· g Au -1 · s -1 , at room temperature) above those reported in the literature for gold on similar oxide supports. Therefore, this method gives better results than the most usual methods of deposition-precipitation or co-precipitation.

Carbides / High pressures and temperatures / Synchrotron radiation / Analytical electron microscopy / Density functional theory (DFT) / X-ray diffraction / Powder diffraction structure analysis Abstract. A combined X-ray diffraction, EELS and DFT study of the reaction of rhenium with carbon at high-(P, T ) conditions up to P max ¼ 67 GPa and T max ¼ 3800 K is presented. A hexagonal rhenium carbide, ReC x , was identified as the stable phase at high-(P, T ) conditions. A composition of ReC 0:5 is proposed. No evidence for a cubic ReC polymorph with rocksalt structure, as suggested in the literature, or for any other phase was found at the P-T conditions explored. A preliminary P-T rhenium-carbon phase diagram has been derived and properties such as bulk moduli and elastic stiffness coefficients were obtained.

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