Ancient dental plaque shows milk was Bronze Age beverage
An international team of anthrobiologists has discovered the earliest evidence of milk consumption in the ancient dental calculus – a mineralized dental plaque – of humans in Europe and western Asia. The team found direct evidence of milk consumption preserved in human dental plaque from the Bronze Age to the present day.
Understanding how, where and when humans consumed milk products is a necessary link between human consumption and their livestock. The new research provides direct protein evidence that the milk of all three major dairy livestock – cattle, sheep and goats – has been consumed by human populations for at least 5,000 years. The findings were published in Nature’s Scientific Reports.
Team leader Christina Warinner of the University of Oklahoma said, “Dairy products are a very recent, post-Neolithic dietary innovation, and most of the world’s population is unable to digest lactose, often developing the symptoms of lactose intolerance.” ou.edu
New tool to detoxify drinking water: ash from cigarette butts
Arsenic can be removed from drinking water through sophisticated treatment methods. Now scientists have found a low-cost, simple, one-step method to remove the poison in areas where technology lags: cigarette ashes.
Researchers led by Jun Yang of China’s Beihang University prepared cigarette ash with a coating of aluminum oxide.
When they tested the material with contaminated ground water, they found the ash removed more than 96 percent of arsenic, reducing its levels to below the standard set by the World Health Organization. Because cigarette ashes are discarded in countries around the world, they can be easily collected in places where public smoking is allowed.
The researchers reported their method in the American Chemical Society journal Industrial & Engineering Chemistry Research. acs.org
Take note: Rewritable paper is under development
Chemists at the University of California at Riverside have fabricated rewritable paper: It is essentially film – glass or plastic – to which letters and patterns can be repeatedly printed, retained for days and then erased by heating.
The technology is based on the color-switching property of commercial chemicals called redox dyes.
The dye forms the imaging layer of the paper. Printing is achieved by using ultraviolet light to photo-bleach the dye, except the portions that constitute the text on the paper.
The new rewritable paper can be erased and written on more than 20 times with no significant loss in contrast or resolution.
It comes in three primary colors: blue, red and green. The combination of the dye, catalysts and thickening agent lends high reversibility and repeatability to the film.
“The printed letters remain legible with high resolution at ambient conditions for more than three days – long enough for practical applications such as reading newspapers,” the team’s leader, chemist Yadong Yin, said.
The study results are published online in Nature Communications. His lab is currently working on a paper version of the rewritable paper. ucr.edu