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In the article, electrochromic WO3 films were obtained from 25, 100, and 200 mM peroxytungstic acid (PTA) solution. A chronoamperogram of the cathodic reduction of tungsten oxide (WO3) through the stages of formation of a precursor film adsorbed on the surface of the ITO electrode and its subsequent staged reduction to WO3 and side formation of soluble reaction products is presented. The material yield of the WO3 film on ITO glass was within 50%, which is due to the parallel occurrence of side processes associated with hydrogen evolution and the reduction of tungsten complexes that were in the precipitation solution (WO3 reduction scheme). In this case, it was taken into account that thin WO3 films were the final product. The features of the synthesis of peroxytungstic acid have been studied. It has been shown that the reaction of W dissolution in 37% H2O2 proceeds exothermically. In this case, the reaction temperature reached 96°C within a few seconds, and its decline varied exponentially with the formation of reaction products. The dependence of the limiting current on the square root is obtained. The presented graphic dependence is characterized by linearity, while the beginning of the straight line does not coincide with the origin. The process of intercalation-deintercalation of protons (H+) (cathode-anode branches of CV) was a consequence of structural and reversible changes as a result of H+ intercalation. WO3 films obtained by electrochemical (cathodic) deposition can be recommended as an electrode material for electrochromic devices (cathode) and as a material for electrochemical sensors. Another promising direction is the development of a wide band gap anode based on WO3 for photovoltaic devices, which are energy efficient hydrogen generation systems. [ABSTRACT FROM AUTHOR]

Abstract—The mechanism of the electrochemical formation of WO3 films on the surface of titanium, tin, and ITO electrodes is investigated under various regimes, including the deposition time τ = 2000–8000 s and the electrochemical potential of deposition on the cathode in the range from –0.4 to –1 V. A technique for the synthesis of peroxytungstic acid and a method of cathodic electrodeposition are presented. The studies carried out with tin and titanium extend the field of application of WO3 films to technologies of chemical current sources and fuel cells. [ABSTRACT FROM AUTHOR]

Numerous electrochemical and chemical methods are suitable for preparation of tungsten trioxide (WO3) films. Many of these methods, however, have not been carefully studied, so information on the specific features of the WO3 film deposition technology is lacking. This paper describes the preparation of WO3 films by cathodic electrodeposition from the synthesized solution of peroxotungstic acid (PTA) on the surface of thermally expanded graphite (TEG) and titanium electrodes designed as foils. A stepwise pattern of reduction of tungsten oxides from PTA was revealed. The suitability of the WO3 film electrode as a material for electrochemical power industry was experimentally demonstrated. Specifically, WO3/Ti was found to be applicable as a protective coating for hydrogen fuel cells, and WO3/TEG, as a cathode material for asymmetric supercapacitors. Based on the charge-discharge curves for the WO3/TEG electrode used as a cathode in the free volume of th KOH electrolyte, the specific capacitance of the supercapacitor was estimated at 630 F/g. Electrochemical analysis showed that that WO3 films deposited on the titanium surface afford enhancement of the hydrogen overpotential and protection against pitting corrosion during potentiostatic polarization tests at the cathode potential of a fuel cell. [ABSTRACT FROM AUTHOR]

Vitamin D affects calcium metabolism and prevents proliferation of colon cells in vitro. In human beings the main circulating form of vitamin D is 25-hydroxyvitamin D; to regulate calcium homoeostasis, this form must be converted to 1alpha, 25-dihydroxyvitamin D by 1alpha-hydroxylation in the kidney with 25-hydroxyvitamin D-1alpha-hydroxylase. Cultured transformed colon cancer cells can convert 25-hydroxyvitamin D(3) to 1alpha,25-dihydroxyvitamin D(3). We identified messenger RNA (mRNA) for 25-hydroxyvitamin D-1alpha-hydroxylase in normal colon tissue and in malignant and adjacent normal colon tissue. These findings support the notion that vitamin D might have a role in cell growth regulation and cancer protection, and might be the explanation for why the risk of dying from colorectal cancer is highest in areas with the least amount of sunlight. [ABSTRACT FROM AUTHOR]