Hot water from cold. The dissociative recombination of water cluster ions.

Dissociative recombination of the Zundel cation D(5)O(2)(+) almost exclusively produces D + 2 D(2)O with a maximum kinetic energy release of 5.1 eV. An imaging technique is used to investigate the distribution of the available reaction energy among these products. Analysis shows that as much as 4 eV can be stored internally by the molecular fragments, with a preference for producing highly excited molecular fragments, and that the deuteron shows a nonrandom distribution of kinetic energies. A possible mechanism and the implications for these observations are addressed.

Heat stability of chaetoglobosins A and C.

Chaetomium globosum is commonly found in water-damaged buildings and produces the mycotoxins chaetoglobosin A and chaetoglobosin C (Ch-A and Ch-C, respectively). While attempting to purify Ch-A and Ch-C, we observed that these mycotoxins were broken down after heating. The objective of this study was to determine the temperature and the amount of time necessary to break down Ch-A and Ch-C. We demonstrated that the amounts of Ch-A were significantly reduced when exposed to 75 degrees C for 24 h and 100 degrees C for 90, 120, or 150 min. Under the same conditions, the levels of Ch-C were also lower (although not significantly). At 175 degrees C, no Ch-A was detected after 15 min and Ch-C was significantly reduced after 30 min. Our findings will aid other researchers who work with these mycotoxins in the future.

Three-body breakup in the dissociative recombination of the covalent triatomic molecular ion O3+.

We report the first observation of almost exclusive three-body breakup in the dissociative recombination of a covalent triatomic molecular ion O3+. The three-body channel, constituting about 94% of the total reactivity, has been investigated in detail. The atomic fragments are formed in only the first two electronic states, 3P and 1D, while formation in the 1S state has not been observed. The breakup predominantly proceeds through dissociative states with linear geometry.

An investigation into techniques for cleaning mold-contaminated home contents.

This study examined the efficacy of the following treatments to reduce selected fungal spore and mycotoxin levels on materials commonly found in home contents: (1) gamma irradiation at a 10-13 kiloGray exposure, (2) a detergent/bleach wash, and (3) a steam cleaning technique. A minimum of six replicates were performed per treatment. Paper, cloth, wood, and carpet were inoculated with either fungal spores (Stachybotrys chartarum, Aspergillus niger, Penicillium chrysogenum, or Chaetomium globosum) at 240,000 spores/2.54 cm2 of material or with the mycotoxins roridin A, T-2, and verrucarin A at 10 microg per 2.54 cm2 of material. Treatments were evaluated with an agar plating technique for fungal spores and a yeast toxicity culture assay for mycotoxins. Results showed that gamma irradiation inactivated fungal spores, but the treatment was not successful in inactivating mycotoxins. The washing technique completely inactivated or removed spores on all materials except for C. globosum, which was reduced on all items except paper (p < 0.05). Washing inactivated all mycotoxins on paper and cloth but not on carpet or untreated wood (p < 0.001). The steam cleaning treatment did not completely eliminate any fungal spores; however, it reduced P. chrysogenum numbers on all materials, C. globosum was reduced on wood and carpet, and S. chartarum was reduced on wood (p < 0.05). Steam cleaning was unsuccessful in inactivating any of the tested mycotoxins. These results show that the bleach/detergent washing technique was more effective overall in reducing spore and mycotoxin levels than gamma irradiation or steam cleaning. However, the other examined techniques were successful in varying degrees.