We investigated the significance of PI3K/AKT/mTOR pathway and its interactions with MAPK, JAK/STAT and Notch pathways in meningioma progression. Paraffin-embedded tissue from 108 meningioma patients was analysed for the presence of mutations in PIK3CA and AKT1. These were correlated with the expression status of components of the PI3K/AKT/mTOR pathway, including p85α and p110γ subunits of PI3K, phosphorylated (p)-AKT, p-mTOR, p-p70S6K and p-4E-BP1, as well as of p-ERK1/2, p-STAT3 and Notch-1, clinicopathological data and patient survival. A mutation in PIK3CA or AKT1 was found in around 9 % of the cases. Higher grade meningiomas displayed higher nuclear expression of p-p70S6K; higher nuclear and cytoplasmic expression of p-4E-BP1 and of Notch-1; lower cytoplasmic expression of p85αPI3K, p-p70S6K and p-ERK1/2; and lower PTEN Histo-scores (H-scores). PTEN H-score was inversely correlated with recurrence probability. In univariate survival analysis, nuclear expression of p-4E-BP1 and absence of p-ERK1/2 expression portended adverse prognosis, whereas in multivariate survival analysis, p-ERK1/2 expression emerged as an independent favourable prognostic factor. Treatment of the human meningioma cell line HBL-52 with the PI3K inhibitor LY294002 resulted in reduction of p-AKT, p-p70S6K and p-ERK1/2 protein levels. The complex interactions established between components of the PI3K/AKT/mTOR pathway, or with components of the MAPK, JAK/STAT and Notch-1 pathways, appear to be essential for facilitating and fuelling meningioma progression.

Ternary nanocomposite systems of PVDF/Fe3O4/CNT and PVDF/Fe3O4/GN, prepared with twin screw compounding method, exhibit enhanced microwave absorption properties.

Natural rubber (NR) nanocomposites have been prepared with hydroxylated barium titanate filler (BaTiO3-OH), employing emulsion polymerization followed by vulcanization process. The addition of barium titanate, a compound with high dielectric permittivity, was envisaged to increase the insulating properties of NR films, thereby reducing the electrical stress and the possibility of undesired arcing on their surfaces. The content of perovskite particles greatly affected both, the mechanical and the electrical properties, of the vulcanized films. It was observed that the optimum functionalized nanoparticle concentration is around 0.25-0.50 phr, range in which the elongation of break was maintained between 874-935 % and the tensile strength was between 4.40-4.80 MPa; whereas the dielectric permittivity (ε') is slightly lower than the pristine NR or the NR compounded with high content of BaTiO3 nanoparticles. The dielectric study revealed the presence of two dielectric relaxation modes: (i) glass to rubber transition (α-relaxation) and (ii) interfacial polarization (IP), known as Maxwell−Wagner−Sillars (MWS) polarization. The comparison between small concentrations of non-functionalized and functionalized BaTiO3 inside NR polymeric films lead to the conclusion that the dielectric breakdown strength is high for non-functionalized fillers, supposedly due to less IP polarization phenomena.

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High volume fraction carbon nanotube (CNT) composites (7.5–16% vol.) were fabricated by the impregnation of CNT buckypapers into epoxy resin. To enhance the interfacial reaction with the epoxy resin, the CNTs were modified by two different treatments, namely, an epoxidation treatment and a chemical oxidation. The chemical treatment was found to result in CNT length severance and to affect the porosity of the buckypapers, having an important impact on the physico-mechanical properties of the nanocomposites. Overall, the mechanical, electrical, and thermal properties of the impregnated buckypapers were found to be superior of the neat epoxy resin, offering an attractive combination of mechanical, electrical, and thermal properties for multifunctional composites.