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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]

A preponderance of carcinogenesis studies in rodents and epidemiologic studies in humans suggests a potential role of dietary fiber in the prevention of colorectal cancer. Recently, wheat bran fiber used as a dietary supplement has been shown to decrease the growth of rectal adenomatous polyps in patients with familial polyposis; however, few studies of high-risk human populations have been attempted to determine the effects of dietary fiber supplementation on markers of carcinogenesis in the colon or rectum. We have designed a one-arm study to evaluate the effects of dietary supplementation with wheat bran fiber [i.e., 13.5 g/day for 8 wk; after 1 mo, 2 g/day (compliance evaluation period)] on [3H]thymidine rectal mucosa cell labeling (i.e., percent of epithelial cells incorporating [3H]thymidine into DNA in intact rectal crypt cells over a 90-min exposure as well as in minced rectal biopsy tissue over a 24-hr exposure) in rectal biopsy specimens. The biopsy specimens were obtained at sigmoidoscopy in 17 compliant patients with a history of resected colon or rectal cancer. We categorized patients as having initially low or initially high [3H]thymidine-labeling indices (i.e., percent of mucosa cells that incorporate [3H]thymidine into DNA during 1.5- or 24-hour in vitro incubations) by using the median baseline labeling index as a cutoff between high and low values. On the basis of a chi-square test used to identify patients with a statistically significant (P less than .001) change, six of the eight patients who initially had high 24-hour outgrowth labeling indices showed a significant decrease in the rectal mucosa biopsy specimens obtained after treatment. An overall 22% decrease was observed in rectal mucosa cell biopsy specimens obtained at study termination (P less than .001). Of the eight patients with initially high total [3H]thymidine-labeling indices in crypt organ culture, four had a significant (P less than .001) decrease from baseline values, one had a significant increase, and three showed no change following the fiber intervention. The wheat bran fiber dietary supplement of 13.5 g/day was well tolerated by this group of older (54-70 yr) patients. Although the [3H]-thymidine labeling index data suggest that the wheat bran fiber supplement can inhibit DNA synthesis and rectal mucosa cell proliferation in high-risk patients, the results of this small pilot study should not be overinterpreted vis à vis the potential role of wheat bran fiber as a chemopreventive agent for colorectal cancer.(ABSTRACT TRUNCATED AT 400 WORDS)

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]

We derive the phase diagram of a recently proposed model of microemulsions. The model is equivalent to an Ising model with nearest-neighbor interaction parameter J, diagonal-neighbor interaction parameter 2M, and further-neighbor interaction parameter M. We find the regions of stability of the various phases in the j(=J/kT), m(=M/kT) plane, both by solution of the mean-field equations at finite j and m and by an exact analysis at T=0(m→-∞, j→±∞). The disordered (paramagnetic) region is bounded by an ellipse and two of its tangents. We concentrate our attention on the phases of periodic structure near the paramagnetic boundary, on the low-temperature phases, and on the connections between them. [ABSTRACT FROM AUTHOR]