Here is the latest American Chemical Society (ACS) Office of Public Affairs Weekly PressPac with news from ACS’ 34 peer-reviewed journals and Chemical & Engineering News.
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Please cite the individual journal, or the American Chemical Society, as the source of this information.
“Green” roofs, those increasingly popular urban rooftops covered with plants, could help fight global warming, scientists in Michigan are reporting. The scientists found that replacing traditional roofing materials in an urban area the size of Detroit, with a population of about one-million, with green would be equivalent to eliminating a year’s worth of carbon dioxide emitted by 10,000 mid-sized SUVs and trucks. Their study, the first of its kind to examine the ability of green roofs to sequester carbon which may impact climate change, is scheduled for the Oct. 1 issue of ACS’ Environmental Science & Technology, a semi-monthly journal.
Kristin Getter and colleagues point out in the new study that green roofs are multi-functional. They reduce heating and air conditioning costs, for instance, and retain and detain stormwater. Researchers knew that green roofs also absorb carbon dioxide, a major greenhouse gas that contributes to global warming, but nobody had measured the impact until now.
The scientists measured carbon levels in plant and soil samples collected from 13 green roofs in Michigan and Maryland over a two-year period. They found that green roofing an urban area of about one million people would capture more than 55,000 tons of carbon, the scientists say. That’s an amount “similar to removing more than 10,000 mid-sized SUV or trucks off the road a year,” the article notes.
Journal: Molecular Pharmaceutics
Journal Article: “Ethanol-Drug Absorption Interaction: Potential for a Significant Effect on the Plasma Pharmacokinetics of Ethanol Vulnerable Formulations”
Controlled release pills and capsules that show a tendency in the standard laboratory test toward “dose dumping” — releasing their medicine in a faster and potentially unsafe manner in patients who have consumed alcohol — should be withheld from the market until proven safe with testing in people. That’s the conclusion of a review of existing studies in the September-October issue of ACS’ Molecular Pharmaceutics, a bi-monthly journal.
In the article, Hans Lennernäs analyzed the gastrointestinal factors that may contribute to dose dumping when a vulnerable formulation interacts with alcohol present in the stomach. However, these factors are highly variable and depend on individual drinking behavior, whether food is present in the stomach, and other circumstances. That makes it “almost impossible” to predict whether a patient will experience an overdose as a result of dose dumping.
Lennernäs thus concludes that when laboratory testing of a product indicates that the drug will be released more quickly than intended, the product also should be tested in humans, or it should be re-formulated. Indeed, Lennernäs believes that lab testing over a two hour period in a range of alcohol strengths is an “absolute minimum standard” in screening for dose dumping because products with a problem in the lab may also be dangerous to patients. Lennernäs cites as an example a formulation of the pain medication hydromorphone, which was removed from the U.S. market when testing revealed that alcohol intake caused the risk of overdose. He noted, however, that there is currently a generic oxycodone product on the market in the European Union which will “most likely” lead to dose dumping in patients.
Denver released the largest amount of greenhouse gases (GHG) and Barcelona the smallest amount in a new study documenting how differences in climate, population density and other factors affect GHG emissions in global cities. The study, which could identify ways in which cities can reduce GHG emissions, is scheduled for October 1 issue of ACS’ Environmental Science & Technology, a semi-monthly journal.
Christopher Kennedy and colleagues note in the new study that some cities are developing strategies to reduce releases of GHG, which include carbon dioxide, methane, and other gases that can contribute to global warming through the greenhouse effect. Not enough information was previously available on why emissions vary considerably among different cities. The authors asked, “How and why do emissions differ between cities?”
To help answer those questions, the scientists analyzed those variations and how climate, power generation, transportation, waste processing, and other factors contributed to the differences. Denver had the highest overall GHG emissions, with levels two to five times higher than other cities. Its high levels were due partly to its high use of electricity, heating and industrial fuels, and ground transportation, they note. Los Angeles was second on the list, followed by Toronto and Cape Town (tied for third), Bangkok, New York City, London, Prague, Geneva, and Barcelona.
Imagine a gift wrapped in paper you really do treasure and want to carefully fold and save. That’s because the wrapping paper lights up with words like “Happy Birthday” or “Happy Holidays,” thanks to a built in battery — an amazing battery made out of paper. That’s one potential application of a new battery made of cellulose, the stuff of paper, being described in the October 14 issue of ACS’ Nano Letters, a monthly journal.
Albert Mihranyan and colleagues note in the report that scientists are trying to develop light, ecofriendly, inexpensive batteries consisting entirely of nonmetal parts. The most promising materials include so-called conductive polymers or “plastic electronics.” One conductive polymer, polypyrrole (PPy), shows promise, but was often regarded as too inefficient for commercial batteries. The scientists realized, however, that by coating PPy on a large surface area substrate and carefully tailoring the thickness of the PPy coating, both the charging capacity and the charging (discharging) rates can be drastically improved. The secret behind the performance of this battery is the presence of the homogeneous, uninterrupted, nano-thin coating — about 1/50,000th the thickness of a human hair — of PPy on individual cellulose fibers which in turn can be molded into paper sheets of exceptionally high internal porosity. It was special cellulose, extracted from a certain species of green algae, with 100 times the surface area of cellulose found in paper. That surface area was key to allowing the new device to hold and discharge electricity very efficiently.
The innovative design of the battery cell was surprisingly simple yet very elegant since both of the electrodes consist of identical pieces of the composite paper separated by an ordinary filter paper soaked with sodium chloride serving as the electrolyte. The potential difference is solely due to differences between the oxidized and reduced forms of the functional PPy layer. The battery recharged faster than conventional rechargeable batteries and appears well-suited for applications involving flexible electronics, such as clothing and packaging, the scientists say. Alternatively, low-cost very large energy storage devices having electrodes of several square yards in size could potentially be made in the future.
The pavement material that cars drive on may wind up in their fuel tanks as scientists seek ways of transforming asphaltenes — the main component of asphalt — into an abundant new source of fuel, according to the cover story in the current issue of Chemical & Engineering News, ACS’ weekly newsmagazine.
C&EN senior editor Celia Henry Arnaud notes that rich supplies of asphaltene exist in Canada, Mexico, and Venezuela. But converting this heavy, sticky material into something other than “blacktop” remains a challenge. Sometimes derided as “the cholesterol of petroleum,” asphaltenes are difficult to extract from deposits and clog refinery pipes, the article notes.
Scientists, however, are using newly crafted analytical techniques to probe the molecular structure of asphaltenes in the quest for better ways of producing and refining asphaltene-rich fuel sources in the future.
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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.
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