Here is the latest American Chemical Society (ACS) Weekly PressPac from the Office of Public Affairs. It has news from ACS’ 34 peer-reviewed journals and Chemical & Engineering News.
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Scientists in Italy are reporting development and successful use of a fast new method to identify food additives that act as so-called “xenoestrogens” — substances with estrogen-like effects that are stirring international health concerns. They used the method in a large-scale screening of additives that discovered two additives with previously unrecognized xenoestrogen effects. Their report appears in the current edition of ACS’ Chemical Research in Toxicology, a monthly journal.
In the study, Pietro Cozzini and colleagues cite increasing concern about identifying these substances and about the possible health effects. Synthetic chemicals that mimic natural estrogens (called “xenoestrogens,” literally, “foreign estrogens”) have been linked to a range of human health effects. They range from reduced sperm counts in men to an increased risk of breast cancer in women.
The scientists used the new method to search a food additive database of 1,500 substances, and verified that the method could identify xenoestrogens. In the course of that work, they identified two previous unrecognized xenoestrogens. One was propyl gallate, a preservative used to prevent fats and oils from spoiling. The other was 4-hexylresorcinol, used to prevent discoloration in shrimp and other shellfish. “Some caution should be issued for the use of propyl gallate and 4-hexylresocrinol as food additives,” they recommend in the study. -MB
Journal: Chemical Research in Toxicology
Journal Article: “Identification of Xenoestrogens in Food Additives by an Integrated in Silico and In Vivo Approach”
Scientists in Germany are reporting development of a new, more effective method to determine whether milk marketed as “organic” is genuine or just ordinary milk mislabeled to hoodwink consumers. Their report appears in the current edition of ACS’ Journal of Agricultural and Food Chemistry, a bi-weekly publication.
In the study, Joachim Molkentin and colleagues point out that organic milk has soared in popularity in many countries. Sales in Germany, for instance, rose by almost one-third between 2006 and 2007. Consequently, crooks may take advantage of the situation by marketing increasing quantities of fake organic milk. That situation created a need for better tests to detect the fraud.
To address the issue, the scientists developed a test based on an analysis of milk fat for the ratio of stable isotopes of carbon. They used it to identify milk samples from cows raised on feed containing a higher ration of maize. Such a feeding regimen is typical of conventional milk production. Organically raised cows are fed less maize but more pasture feed. In addition, the team identified a significant difference in the alpha-linolenic acid content of milk fat between organic and conventional milk samples. Organic milk typically has a higher alpha-linolenic acid content than conventional milk. -MB
Scientists in Washington state are reporting the surprise discovery of the oldest known sample of reactor-produced bomb-grade plutonium, a historic relic from the infancy of America’s nuclear weapons program. Their research, which also represents the first demonstration of how radioactive sodium can be used as a tool in nuclear forensics, appears in the current issue of ACS’ Analytical Chemistry, a semi-monthly journal.
In the new study, Jon Schwantes and colleagues note increased concern about the possibility of terrorists smuggling radioactive materials to make illegal nuclear weapons. As a result, scientists are stepping up efforts to identify and track the source of these radioactive materials using the advanced tools and techniques of a new field called “nuclear archaeology.”
The scientists describe efforts to determine the origin of an unknown sample of plutonium (Pu) found in 2004 in a bottle at a waste burial trench at the Hanford nuclear site in Washington. Hanford is the earliest location for U.S. plutonium production for nuclear weapons and now the focus of a massive environmental cleanup effort due to high levels of radioactive waste that remain at the site.
Using multiple pairs of “parent” Pu and “daughter” uranium (U) isotopes, the researchers were able to correct for chemical fractionation that occurred as a result of repackaging in 2004 and determine the age of the sample. Using this technique, they estimated that the Pu in the sample had been separated from U and fission products in 1944, making it the oldest known sample of bomb-grade plutonium produced in a reactor. The only older known samples of Pu-239 were produced by the late Glenn Seaborg and his associates in the beginning of the 1940's when the existence of the element was first confirmed and characterized.
The study identified the Clinton reactor in Oak Ridge, Tenn., as reactor of origin for this material, by comparing reactor burnup modeling results with measurements of minor Pu isotopes. These results were also supported by a series of historical documents tracking the material's movement from Oak Ridge and the processing at Hanford. “Aside from the historical significance of this find, this work provides the public a rare glimpse at a real-world example of the science behind and power of modern-day nuclear forensics,” the scientists note. -MTS
Journal: Analytical Chemistry
Journal Article: “Proteomic and Behavioral Analysis of Response to Isoliquiritigenin in Brains of Acute Cocaine Treated Rats”
In a finding that could help speed the understanding of diseases ranging from cancer to osteoporosis, researchers in Utah are reporting development of a new microscope technique that uses “silver nanoparticle” mirrors to reveal hidden details inside bones, cancer cells, and other biological structures. The method also can help identify structural damage in a wide variety of materials, including carbon-fiber plastics used in airplanes, the researchers say. Their study is scheduled for the March issue of ACS’ Nano Letters, a monthly journal.
In the new study, John Lupton and colleagues point out that one of the most powerful, widely used tools for imaging hidden biological structures is fluorescence microscopy, which requires the specimen to be treated with fluorescent dyes or stains. But the dyes used to visualize the structures can kill living cells, limiting the effectiveness of the technique, the researchers note.
The scientists improved on this technique by using an infrared laser to excite clusters of silver nanoparticles, each about 1/5000th the width of a human hair, placed below the material being studied. The particles focus intense beams of light up through the sample to reveal information about the composition and structure of the substance examined, the scientists say. In laboratory studies, they used the new technique to view the iridescent green scales of the so-called “photonic beetle,” whose scales may provide clues to designing new, more powerful solar cells and computer chips, the scientists say. - MTS
Super-thin films of carbon with exotic properties, now taking the scientific world by storm, may soon mean a new era of brighter, faster, and smaller computers, smart phones, and other consumer electronics. Brighter digital displays that flex like a sheet of paper. Faster computer chips. Smaller computers. That’s the word from an article scheduled for the March 2 issue of Chemical & Engineering News, ACS’ weekly newsmagazine.
In the magazine’s cover story, C&EN Senior Editor Mitch Jacoby notes that these so-called graphene sheets — 50,000 times thinner than the width a single human hair — were first isolated by researchers just a few years ago. The nano-size sheets perform better than life-size carbon, with higher strength and the ability to conduct electricity faster. These properties make them attractive for developing new and improved electronic devices, the article notes.
Scientists in academia and industry have stepped up their efforts to improve the performance and manufacture of graphene sheets. At least one company plans to produce the sheets on an industrial scale in ton quantities. Scientists had predicted the existence of these unusual carbon sheets just a few years ago but had not produced actual thin-films until recently. “Graphene is one of the hottest topics in materials science these days,” says one authority in the C&EN article.
It's never too late to explore a treasure trove of news sources, background material and story ideas available from the ACS' latest National Meeting, which was held in Philadelphia from August 17-21, 2008. Reporters can view press releases, search an archive with abstracts of more than 9,000 scientific presentations and hundreds of non-technical summaries of those presentations, and access other resources at: www.eurekalert.org/acsmeet.php.
The ACS Office of Public Affairs also offers recorded video versions of its national meeting "chat room" briefings and accompanying chat transcripts by going to http://www.ustream.tv/channel/acslive. To use this site, you must first register with Ustream.tv by going to http://ustream.tv/sign-up-step-1. It's free and only takes a minute or two to sign up. To view the archived chat room sessions, proceed by clicking the "Login" button at the top right of the Ustream window and then selecting "Past Clips." Please note that Ustream requires the latest version of Adobe Flash, which can be downloaded without charge at http://www.adobe.com/products/flashplayer.
CAS - Science Connections is a series of articles that showcases the value of CAS databases in light of important general-interest science and technology news. Ranging in topics from fruit flies to Nobel Prize winners, the CAS - Science Connections series points to the CAS databases for a more complete understanding of the latest news.
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PressPac information is intended for your personal use in news gathering and reporting and should not be distributed to others. Anyone using advance PressPac information for stocks or securities dealing may be guilty of insider trading under the federal Securities Exchange Act of 1934.
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.
Journal: Chemical & Engineering News
Journal Article: “Graphene: carbon thin as can be”
This story will be available on March 2.