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With meteorologists concerned about a possible worldwide intensification of tornado activity, scientists in Germany are proposing a new approach to studying formation of twisters, which pack Earth’s most violent winds. It involves forming microtornadoes under millimeter-scale crystalline “igloos,” according to a report by Andrei P. Sommer scheduled for publication in the June 6 edition of ACS’ Crystal Growth & Design, a bi-monthly journal.
In the report, Sommer describes evaporating tiny drops of water laced with polystyrene nanospheres to form the transparent igloos. The drops consisted of 15-microliters of liquid — 15 millionths of a liter — and formed the translucent “igloos” after being deposited on a surface under an evaporation chamber. As the drops evaporated (taking 191 hours, a record for such experiments), Sommer observed patterns formed by swirling micro-vortexes that appeared similar to those formed by tornadoes under real-world conditions.
Because the conditions favoring the formation of the microtornadoes are identical to those forming real tornadoes, Sommer suggested that such igloos and microtornadoes could become an important new tool for meteorologists seeking to understand how certain atmospheric conditions spawn tornadoes. “By simultaneously wetting the roof of such an igloo, if necessary, and injecting minimal amounts of water containing nanospheres into it, it should be possible to mimic basic processes in tornadoes experimentally and to explore the impact of relevant boundary conditions including terrain conditions and cloud cover stability,” the report states.
Journal: Crystal Growth & Design
Journal Article: “Microtornadoes under a Nanocrystalline Igloo: Results Predicting a Worldwide Intensification of Tornadoes”
In an advance toward understanding the contradictory health effects of bioflavonoids, scientists in Tennessee are reporting that these natural components of fruits and vegetables poison a key human enzyme critical for the normal function of DNA. The research is scheduled for publication in the May 22 issue of ACS’ Biochemistry, a weekly journal.
Neil Osheroff and Omari J. Bandele point out that bioflavonoids are the most abundant natural source of antioxidants in the diet, and ordinarily are considered quite beneficial in protecting against heart disease, cancer, and other health problems. Despite the benefits, bioflavonoids also have toxic effects, with ingestion of high levels among pregnant women linked to rare forms of infant leukemia.
In their laboratory study, the researchers showed that bioflavonoids poison topoisomerase II in cultured human cells. This enzyme plays important roles in many critical DNA processes and removes knots and tangles from the genome. The enzyme acts by making a double-stranded cut in DNA, passing another segment of the double helix through the break, and reconnecting the broken strands. The study found that three major classes of bioflavonoids interfere with the enzyme in cells, leading to DNA damage with potential adverse health effects. The findings provide important new insights into how flavonoids act, the researchers say.
The grime that accumulates on windows, buildings, roads, and other surfaces in urban areas could be an important source of nitrogen oxide air pollutants, scientists in Canada conclude in a report scheduled for the June 15 issue of ACS’ Environmental Science & Technology, a semi-monthly journal. Nitrogen oxides, emitted in the burning of fossil fuels, combine with other air pollutants termed volatile organic compounds to form smog.
In the report, D. J. Donaldson and colleagues point out that air pollution researchers have been focusing on urban surface films, often termed “window grime,” as a potential contributor to air pollution. The films contain nitrogen compounds, which disappear at rates that can’t be explained by obvious losses due to rain washout. In addition, traditional models of urban air pollution suggest that there must be an important but unrecognized source for one nitrogen compound involved in smog formation.
Their study presents experimental evidence suggesting that windows and other surfaces in urban areas may be sites where “inactive” nitrogen oxides may be transformed into “active” forms and be released to the atmosphere. This transformation may occur in a process triggered by sunlight shining on film-covered surfaces, the report notes.
Scientists in Italy are reporting development and use on Renaissance masterpieces of a simple, less-expensive method for the world’s most delicate cleanups — on precious paintings and other works of art. The methods use oil-in-water nanocontainers to restore artwork dulled by centuries-old buildups of grime and damaged from floods and failed past attempts at preservation, according to a study scheduled for the May 22 issue of ACS’ Langmuir, a bi-weekly journal.
In the study, Piero Baglioni and colleagues describe tiny droplets of cleaning agents suspended in water to form microemulsions. These nanocontainers have several advantages over traditional methods, which may involve the use of pure organic solvents. The microemulsions have a milder cleaning action, for instance, less likely to damage fragile surfaces. In addition, they use up to 95 percent less organic solvent and have less of an environmental impact than traditional cleaning methods. “These innovative systems are very attractive for the low amount of organic solvent. . . and the very efficient and mild impact of the cleaning procedure on the fragile painted surfaces,” the report states.
Researchers report on successful use of the technology in actual restorations, including a Renaissance painting that had been degraded by application of a polyacrylate coating during a previous restoration attempt and removing tar-like deposits from a fresco in Florence that was damaged during the 1996 flooding of the Arno River.
Store shelves hold aisles of attractively packaged lipsticks, shampoos, toothpastes and other personal care products. But those attractively packaged products also contain their own internal microscopic packets of moisturizers, vitamins, anti-bacterial agents, and other active ingredients. Now these widely used products are getting a new generation of “smart” delivery systems — microencapsulation systems that more efficiently deposit precious payloads into the body, according to an article scheduled for the May 14 issue of Chemical & Engineering News (C&EN), ACS’s weekly newsmagazine.
In the article, C&EN senior editor Marc S. Reisch explains that these minute “envelopes” long have been used to protect active ingredients that might otherwise degrade before reaching their intended bodily destinations. “Lately, these envelopes have become part of elaborate new systems with street smarts,” Reisch writes. Although some deposit their contents when broken open with friction, others meter out increasingly expensive ingredients in response to changes in moisture, acidity, the presence of bacteria, or other triggers.
The article describes sweeping advances in encapsulation technology for personal care products, including encapsulation systems headed for the market in the months ahead. The systems represent significant improvements over those used in the past, and may open the door to the use of encapsulated ingredients in a wider range of products available at economical prices, Reisch adds.
The Philadelphia Section, American Chemical Society, and Ursinus College will host the 39th ACS Middle Atlantic Regional Meeting.
This pioneering conference on one of the hottest topics in chemistry will be held June 26-29, 2007 at the Capital Hilton hotel in Washington, DC.
The American Chemical Society — the world’s largest scientific society — is a nonprofit organization chartered by the U.S. Congress and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.