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Fluorine doped tin oxide thin films were prepared from solutions with high fluorine contents using the spray pyrolysis technique; the resulting films were studied by electron and X-ray diffraction methods; the resonant nuclear reaction (RNR) method was used to determine the final concentration of fluorine atoms in our films for different doping levels. Also, electrical and optical properties of SnO2:F films were measured and correlated with deposition and structural parameters obtained from X-Ray diffraction and electron microscopy studies.

A method using ultra performance liquid chromatography coupled with tandem mass spectrometry was developed to measure cobalamins in naturally enriched raw milk and to evaluate their fate during thermal treatments and along the process of cheese making. After addition of methotrexate as internal standard, samples were submitted to heat treatment in the presence of cyanide, which converts all the less-stable cobalamins into cyanocobalamin; then, purification was performed by a solid-phase extraction step. Reverse-phase ultra performance liquid chromatography separation coupled with tandem mass spectrometry provided a fast and reliable determination. Mass spectrometric analysis was carried out in multiple reaction monitoring mode. The monitored transitions were m/z 678.36 → 147.10 and 678.36 → 359.30 for vitamin B 12 and m/z 455.22 → 175.13 and 455.22 → 308.22 for methotrexate (internal standard). The limit of quantification was 2ng/g. The method showed good linearity from 2 to 20ng/g (R 2 ≥0.98) and intra- and interday precisions were always less than 19%.

The pharmacological treatment of erectile dysfunction relies mostly on the use of sildenafil (Viagra®) and other sildenafil-type selective inhibitors of phosphodiesterase 5 (PDE5). Adverse effects and the cost of the therapy represent a stimulus to search for alternative drugs. With the aim of searching for alternative pharmacological treatments, several plant extracts traditionally used for impotence (Tribulus terrestris L., Ferula hermonis Boiss, Epimedium brevicornum Maxim, Turnera diffusa var. aphrodisiaca (G.H. Ward) Urban, Cinnamomum cassia L.) were screened against PDE5A1 activity. Human recombinant PDE5A1 was prepared by expression of the full-length cDNA into COS-7 cells [1], and the enzyme activity was determined by a radioassay [1]. Statistical analysis was performed using GraphPad Prism 4. Only E. brevicornum extract (80% inhibition at 50µg/ml) and its active principle icariin (IC50 5.9µM) were highly active. In order to improve the inhibitory activity, icariin was submitted to modifications directed to remove the glycosidic moieties, and to replace them with the hydroxyethyl side chain as simplification of the sugar residues, or to cyclize the prenyl group. Compound 3,7-bis (2-hydroxyethyl) icaritin (5), where both sugars were replaced with hydroxyethyl residues, potently inhibited PDE5A1 with an IC50 very close to sildenafil (IC50 75 nM vs. 74 nM). The potency of 5 was 80 fold higher than the lead compound. The improved pharmacodynamic profile, and no sign of cytotoxicity in human fibroblasts make this compound a promising candidate for further development.