Friday, November 5, 2010

SMALL PARTICLES SHOW BIG PROMISE IN BEATING UNPLEASANT ODORS

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Scientists are reporting development of a new approach for dealing with offensive household and other odors — one that doesn't simply mask odors like today's room fresheners, but eliminates them at the source. Their research found that a deodorant made from nanoparticles — hundreds of times smaller than peach fuzz — eliminates odors up to twice as effectively as today's gold standard. A report on these next-generation odor-fighters appears in ACS' Langmuir, a bi-weekly journal.

Brij Moudgil and colleagues note that consumers use a wide range of materials to battle undesirable odors in clothing, on pets, in rooms, and elsewhere. Most common household air fresheners, for instance, mask odors with pleasing fragrances but do not eliminate the odors from the environment. People also apply deodorizing substances that absorb smells. These materials include activated carbon and baking soda. However, these substances tend to have only a weak ability to absorb the chemicals responsible for the odor.

The scientists describe development of a new material consisting of nanoparticles of silica (the main ingredient in beach sand) — each 1/50,000th the width of a human hair — coated with copper. That metal has well-established antibacterial and anti-odor properties, and the nanoparticles gave copper a greater surface area to exert its effects. Tests of the particles against ethyl mercaptan, the stuff that gives natural gas its unpleasant odor, showed that nanoparticles were up to twice as effective as the gold standard — activated carbon — at removing the material's foul-smelling odor. In addition to fighting odors, the particles also show promise for removing sulfur contaminants found in crude oil and for fighting harmful bacteria, they add.

American Chemical Society

RESEARCH REJECTS GREEN TEA FOR BREAST CANCER PREVENTION

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Green tea does not protect against breast cancer. A study of data from approximately 54,000 women, published in BioMed Central's open access journal Breast Cancer Research, found no association between drinking green tea and breast cancer risk.

Motoki Iwasaki, from the National Cancer Center, Tokyo, worked with a team of researchers to carry out the study. He said, "Although in vitro and animal-based studies have suggested that green tea may have beneficial protective effects against breast cancer, results from human studies have been inconclusive. Our large-scale, population-based prospective cohort study is one of the first to include a wide range of tea intakes; women who drank green tea less than 1 cup per week to those who drank 10 or more cups per day. It found no overall association between green tea intake and the risk of breast cancer".

Tea intake was assessed by questionnaire, once at the beginning of the study and then again five years later. Cancer incidence was assessed by notification from major local hospitals in the study area and data linkage with population-based cancer registries. Approximately 12% of women drank green tea less than 1 cup per week while 27% drank 5 or more cups per day. Speaking about the survey, Iwasaki said, "The other major strength of the present study was its prospective design, in which information was collected before the subsequent diagnosis of breast cancer, thereby avoiding the exposure recall bias inherent to case-control studies. Drinking green tea as a beverage is unlikely to reduce the risk of breast cancer regardless of green tea type and number of cups".

BioMed Central

INTO AFRICA? FOSSILS SUGGEST EARLIEST ANTHROPOIDS COLONIZED AFRICA

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A new discovery described by a team of international scientists, including Carnegie Museum of Natural History paleontologist Christopher Beard, suggests that anthropoids—the primate group that includes humans, apes, and monkeys—"colonized" Africa, rather than originally evolving in Africa as has been widely accepted. According to this paper, what is exceptional about these new fossils—discovered at the Dur At-Talah escarpment in central Libya—is the diversity of species present: the site includes three distinct families of anthropoid primates that lived in North Africa at approximately the same time.

This suggests that anthropoids underwent diversification, through evolution, previous to the time of these newly discovered fossils, which date to 39 million years ago. The sudden appearance in the African fossil record of diverse anthropoid families can be answered in one of two ways, the paper's authors say. It could be the result of a striking gap in the African fossil record prior to this period. This is unlikely to be the case as Northern Africa's Eocene sites have been well sampled over the past century, and no diversity of anthropoid fossils has yet been discovered that predates the new Libyan specimens. Therefore, the paleontologists suggest, it is more likely that several anthropoid species "colonized" Africa from another continent 39 million years ago—the middle of the Eocene epoch. Since diversification would have occurred over extreme lengths of time, and likely leave fossil evidence, the new fossils combined with previous sampling in North Africa leads the paper's authors to surmise an Asian origin for anthropoids, as proposed by Beard and his colleagues in earlier work, rather than a gap in the fossil record.

"If our ideas are correct, this early colonization of Africa by anthropoids was a truly pivotal event—one of the key points in our evolutionary history," says Christopher Beard, Curator of Vertebrate Paleontology at Carnegie Museum of Natural History and an author on the paper. "At the time, Africa was an island continent; when these anthropoids appeared, there was nothing on that island that could compete with them. It led to a period of flourishing evolutionary divergence amongst anthropoids, and one of those lineages resulted in humans. If our early anthropoid ancestors had not succeeded in migrating from Asia to Africa, we simply wouldn't exist."

Beard has done extensive research on anthropoid origins, including his work on the primate Eosimias. His popular book, The Hunt for the Dawn Monkey, has been critical in positing Asia, not Africa, as the place of origin for anthropoids. The search for information regarding the origins of man's earliest anthropoid ancestors remains one of the most hotly pursued subjects in paleontology.

"This extraordinary new fossil site in Libya shows us that in the middle Eocene, 39 million years ago, there was a surprising diversity of anthropoids living in Africa, whereas few if any anthropoids are known from Africa before this time," says Beard. "This sudden appearance of such diversity suggests that these anthropoids probably colonized Africa from somewhere else. Without earlier fossil evidence in Africa, we're currently looking to Asia as the place where these animals first evolved."

(Photo: Mark A. Klingler/Carnegie Museum of Natural History, Pittsburgh, Pa)

Carnegie Museum of Natural History

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