Study on the photochemical preparation of nickel gallium oxide spinel doped with Eu(III) ions from carboxylate and beta-diketonate complexes and the evaluation of its optical properties

In this work, Ni(II) carboxylate and Ga(III) beta-diketonate complexes, were studied as precursors for the photochemical deposition of ternary metal oxide thin films with different levels of Eu(III) doping. Diluted solutions of these complexes were mixed, spin-coated on silicon(100) and irradiated at room temperature with a 254 nm UV light. Subsequently, the photodeposited films were annealed at 350, 650 and 950 degrees C. The photochemistry and annealing of these films was monitored by Fourier transform infrared spectroscopy. The obtained samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and UV-vis spectroscopy. The results showed the formation of spinel-type structures (NiGa2O4). The prepared phosphors under UV irradiation revealed red luminescence, which was attributed to transitions from the D-5(0) excited state to the 7Fj ground states of the Eu3+ ions. The intensity of the photoluminescence decreases upon Eu doping, and the performance of these emissions depends strongly on the surface structure and morphology of the photodeposited films.FONDECYT (National Fund for Scientific and Technological Development), Chile 1130114 CONICYT-FONDEQUIP Program EQM-14008

Preliminary evaluation of the up-conversion emission of Y2O3:Er-Yb thin films prepared by a solid state photochemical deposition method

Y2O3 thin films doped with different concentrations of erbium ions and co-doped with 10 mol% of ytterbium were synthesized by a solid state photochemical deposition method followed by a subsequent calcination process. The photo-reactivity of the thin films was monitored by Fourier transform infrared (FT-IR) spectroscopy. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), UV–vis spectroscopy and photo-luminescence (PL) were employed to characterize the samples. The results reveal that Y2O3:Er films under 980 nm irradiation exhibit characteristic up-conversion emissions that are focused in the green region of the spectrum; these emissions are assigned to the (2H11/2, 4S3/2)→4I15/2 transitions of the Er3+ ions. These emissions greatly increase in intensity with the addition of Yb3+ ions in the preparation of the co-doped films. This phenomenon is explained based on the efficient Yb3+ → Er3+ energy transfer processes

Nutrigenomics as strategy for neuronal health

Nutrigenomics through gene expression and epigenetic remodeling can program adult health. Diet during pregnancy and lactation (the first 1000 days of life) can modulate offspring’s epigenome leading to tissue specific variations during cell differentiation processes, and may define epigenetic marks associated with longterm effects on offspring neuronal health. Being epigenetics reversible, a healthy diet represents a fundamental opportunity, even after the first 1000 days of life, for maintaining cellular homeostasis. The positive impact of food (i.e. maternal milk, oily fish, fruit and vegetables, curcumin, tea) with its dietary flavonoids (i.e. sulforaphane, quercetin, lutein, resveratrol, carotenoids) and other bioactive compounds (i.e. docosahexanoic acid, melatonin etc.), will be reflected on chromatin structure modulation and DNA methylation which are associated with switching on/off of genes. An anti-inflammatory diet during early-life and across the whole life may represent a key strategy for influencing brain plasticity and for building an “epigenetic memory” useful in developing neuronal resilience against early-life stressors and to prevent age-related neurodegeneration