Optical and electrochemical properties of CeO2 and CeO2---TiO2 coatings

Thin solid films of CeO₂ and mixed CeO₂---TiO₂ were prepared by the sol-gel route via the dip-coating technique. Particulate sols of ceria were made from inorganic ((NH₄)₂Ce(NO₃)₆) precursor which were used for preparation of CeO₂ thin solid films while CeO₂---TiO₂ coatings have been made by using mixed organic-inorganic (Ti(OiPr)₄ and CeCl₃·7H₂O) precursors. The solar transmission values (T_s) of both coatings are in the range 0.6–0.8 and depend on coating thickness. Cyclic voltammetric (CV) measurements show that the CeO₂/LiOH system exhibits higher overall electrochemical reversibility when compared to the CeO₂---TiO₂/LiOH system. The CeO₂/LiOH system is also less sensitive with regard to the coating thickness. Coulometric measurements show that CeO₂ exhibits a larger storage capability which was determined as a function of the coating thickness. “In situ” UV-VIS spectroelectrochemical measurements which have been performed on CeO₂ and CeO₂---TiO₂ coatings revealed that both types of samples exhibit electrochromic effect in the spectral range 500 < λ < 330 nm but remain unchanged in the visible spectral range.     

Alkaline phosphatase activity in cultured skin fibroblasts from fibrodysplasia ossificans progressiva

Alkaline phosphatase activity in four strains of cultured skin fibroblasts obtained from a patient with fibrodysplasia ossificans progressiva was at the low normal range. The enzyme activity in normal fibroblasts significantly increased at late confluency. It appears that the high levels of alkaline phosphatase activity reported in biopsies of lesions are not genetically determined but are secondary events of local tissue reaction.     

Optical characterization method for black pigments applied to solar-selective absorbing paints

We propose a novel, to our knowledge, method for characterizing the optical properties of pigment particles or powders. Measurements of the diffuse and the total transmittance as well as the diffuse and the total reflectance are used to obtain effective scattering and absorption coefficients per unit length for the particles that are dispersed in a continuous matrix. For dilute dispersions in the single-scattering regime scattering and absorption cross sections of the particles were obtained. The method was applied to two pigments, namely, FeMnCuO(x) and black carbon. The data were obtained by use of pellets consisting of low concentrations of FeMnCuO(x) or black-carbon pigments dispersed in a KBr matrix. The pigment volume concentrations used to evaluate the scattering and the absorption coefficients ranged from 0.053% to 0.530% for FeMnCuO(x) and 0.076% to 0.310% for the black carbon. These ranges were found to exhibit the linear dependence of the coefficients as a function of volume fraction, as given by single-scattering theory.