Photocatalytic antimicrobial activity of thin surface films of TiO(2), CuO and TiO (2)/CuO dual layers on Escherichia coli and bacteriophage T4.

TiO(2)-coated surfaces are increasingly studied for their ability to inactivate microorganisms. The activity of glass coated with thin films of TiO(2), CuO and hybrid CuO/TiO(2) prepared by atmospheric Chemical Vapour Deposition (Ap-CVD) and TiO(2) prepared by a sol-gel process was investigated using the inactivation of bacteriophage T4 as a model for inactivation of viruses. The chemical oxidising activity was also determined by measuring stearic acid oxidation. The results showed that the rate of inactivation of bacteriophage T4 increased with increasing chemical oxidising activity with the maximum rate obtained on highly active sol-gel preparations. However, these were delicate and easily damaged unlike the Ap-CVD coatings. Inactivation rates were highest on CuO and CuO/TiO(2) which had the lowest chemical oxidising activities. The inactivation of T4 was higher than that of Escherichia coli on low activity surfaces. The combination of photocatalysis and toxicity of copper acted synergistically to inactivate bacteriophage T4 and retained some self-cleaning activity. The presence of phosphate ions slowed inactivation but NaCl had no effect. The results show that TiO(2)/CuO coated surfaces are highly antiviral and may have applications in the food and healthcare industries.

Dietary restraint and heightened reactivity to food.

Previously, studies have explored the relationship between dietary behavior and salivary reactivity to food. Despite this, it remains unclear which behaviors are associated with enhanced reactivity. One problem is that measures of behavior have not been compared directly. In particular, it is unclear whether elevated reactivity is associated with measures of dietary restraint or with measures of failed dietary control and a tendency to overeat. To address this problem, we compared the association between salivary reactivity and scores on the subscales of the Three-Factor Eating Questionnaire (restraint, disinhibition, and hunger). Estimates of reactivity were derived from the difference between a baseline saliva measure and a similar measure taken in close proximity to hot pizza. Our second aim was to explore how salivary reactivity changes after a meal. Female participants (N=40) were tested before and after a lunch (cheese sandwiches). All tended to show reactivity to pizza before but not after lunch. No significant differences were associated with the disinhibition or hunger subscales. However, prelunch reactivity was significantly greater in those participants with high scores on the restraint scale. This does not appear to be related to reported levels of hunger before lunch. Rather, it may reveal an intrinsic difference between the reaction of restrained and unrestrained eaters to food.