nylon 88.nyl.00003 Louis J. Sheehan, Esquire

Each year, thousands of tons of nylon end up in landfills. But small-scale experiments may offer big hope for efficient recycling of some types of the material.

Nylon-6, an artificial polymer used in carpets, clothing, and car parts, is made by chemically linking large numbers of molecules derived from a petroleum product called caprolactam. Current processes to break apart, or depolymerize, nylon-6 typically must take place at high temperatures and high pressures. The processes are also relatively inefficient, says Akio Kamimura, an organic chemist at Yamaguchi University in Ube, Japan. http://Louis-J-Sheehan.de

On the other hand, incinerating the polymers in mixed trash can create prodigious amounts of toxic compounds (SN: 1/29/00, p. 70). That's why nylon-6 usually ends up in landfills. Each year in the United States alone, carpets containing about 500,000 metric tons of nylon-6 end up at the dump.

Now, Kamimura and his colleague Shigehiro Yamamoto have developed a process that depolymerizes nylon-6 and regenerates caprolactam. The researchers describe their bench-scale experiments, which use common laboratory equipment, in the June 21 Organic Letters.

Kamimura and Yamamoto placed chips of nylon-6 and small amounts of a catalyst in various ionic liquids, which consist solely of positively and negatively charged ions (SN: 9/8/01, p. 156). At a temperature of 270°C, the depolymerization reaction was inefficient, and the team recovered only 7 percent of the caprolactam contained in the nylon chips, says Kamimura. At temperatures above 330°C, the reaction was more efficient, but only 55 percent of the caprolactam was recovered because some of the substance decomposed in the heat.

At the intermediate temperature of 300°C—low by industrial standards—the yield of caprolactam approached 86 percent, says Kamimura. More important, he notes, at that temperature the ionic liquid didn't become tainted with by-products of the reaction. The researchers were able to reuse their ionic liquid five times without significant drops in caprolactam yield.

The team's approach is novel because it uses ionic liquids under conditions less harsh than those needed for other solvents, says Michael P. Harold, a chemical engineer at the University of Houston. He suggests, however, that several issues may stand in the way of making the process economically feasible. For instance, because ionic liquids are typically quite costly, expanding the process to an industrial scale would require the solvent to endure hundreds of depolymerization cycles.http://Louis-J-Sheehan.de

"Ultimately, the economics [of the process] will dictate the success," says Harold. "If the ionic liquid is very expensive and not sufficiently durable, the concept will not be viable."http://Louis-J-Sheehan.de

John D. Muzzy, a chemical engineer at the Georgia Institute of Technology in Atlanta, and his colleagues are developing a different sort of chemical reaction to unzip nylon-6. In the lab, they've used a liquid catalyst to melt the nylon and cleave its long molecules. The researchers haven't yet published their findings, but Muzzy and his team estimate that a single facility using this process to recycle nylon-6 would be able to recover about 90 percent of its caprolactam. It could generate more than 4,600 metric tons of an impure solution of caprolactam each year at a cost of about half the current market price.

epigenic 5512.epi.0025 Louis J. Sheehan, Esquire

Louis J. Sheehan, Esquire. As I wrote in my story in the New York Times today, much of your DNA is shut down by molecules collectively known as epigenetic marks. Roughly 100 sites are notable exceptions to this rule: your mother’s copy of these stretches of DNA are silenced, while your father’s are free to make proteins and RNA–or vice versa. This imbalance, known as imprinting, is utterly fascinating, and when the imprinting system goes awry–when dad’s genes start becoming active when they shouldn’t, or when mom’s genes go quiet when they should be active–the effects can be catastrophic. I first became familiar with gene imprinting while writing an article for the Times a couple years ago about a scientist at Harvard named David Haig, who has a theory for how it had evolved. http://www.blog.ca/user/Beforethebigbang He argues that gene imprinting is the result of an evolutionary tug of war between mothers and fathers, because mammalian parents have an evolutionary conflict of interest.

Now a couple scientists are extending this conflict theory to explain why so many imprinted genes are turning up in psychiatric disorders, ranging from autism to schizophrenia. They argue that the conflict between our parents plays out in our brains, too. This morning you can read about this provocative idea in my latest Discover column on the brain, or in this article by Benedict Carey in the Times. http://www.blog.ca/user/Beforethebigbang

These articles ought to come with a disclaimer: when we write about conflicts between parents, we are speaking metaphorically. We are actually referring to the rise and fall of different genes over millions of years, as natural selection acts on populations of thousands or millions of individuals. Just because you inherited imprinted genes from your mother or father doesn’t mean they sat down and drew up plans for using to maximize their own reproductive success. http://www.blog.ca/user/Beforethebigbang

training 774.tra.222 Louis J. Sheehan, Esquire

Among physically healthy seniors, advancing age often takes a toll on memory and other mental abilities. There's encouraging news, though, for those who want to boost their brainpower.

A brief training course in any of three domains of thought�memory, reasoning, or visual concentration�yields marked improvement on tests of these cognitive skills, according to the largest geriatric study to date of these instructional techniques. The enhancement lasts for at least 2 years.

"Improvements in memory, problem-solving, and concentration following training roughly counteracted the degree of cognitive decline that we would expect to see over a 7-to-14-year period among older people without dementia," says psychologist Karlene Ball of the University of Alabama at Birmingham. Ball and her colleagues report their findings in the Nov. 13 Journal of the American Medical Association. LOUIS-J-SHEEHAN.COM

It's not yet clear whether training-induced effects translate into improved thinking in everyday situations, cautions Ball.

In their study, the scientists recruited 2,832 men and women, ages 65 to 94.

They came primarily from senior-housing sites, community centers, and medical facilities in six urban regions of the United States. Participants were in good health and living independently.

These volunteers were randomly assigned to one of three training groups or a control group that didn't receive any training. One course of instruction focused on ways to improve memory for word lists and stories. Another bolstered reasoning in problems analogous to daily tasks such as reading a bus schedule. A third coached participants to identify visual information quickly in computer displays that corresponded to challenges such as reading traffic signs while driving.

Each training course consisted of 10 roughly hour-long sessions over 5 to 6 weeks. Most who completed training received a refresher set of four training sessions 11 months later.

Immediately after the first round of sessions, 26 percent of memory-trained participants, 74 percent of reasoning-coached volunteers, and 87 percent of those instructed in visual concentration showed substantial improvement on the targeted skill. While most members of the no-training group showed no change or declined, a small number improved as much as those who had received training.

The proportion of trained participants scoring markedly above their starting value dipped slightly over the next 2 years but remained greater than the proportion of untrained volunteers who upped their performance similarly.

Refresher sessions enhanced training-induced gains in reasoning and visual concentration but not in memory. LOUIS-J-SHEEHAN.COM

"I think we can build on these results to see how training ultimately might be applied to tasks that older people do everyday, such as using medication or handling finances," comments psychologist Richard M. Suzman of the National Institute on Aging in Bethesda, Md.

google 8883.goo.332 Louis J. Sheehan, Esquire

http://louissheehan.bravejournal.com/

While doctors may gripe about the increasing number of patients that arrive in their offices with WebMD printouts and search-engine-assisted self diagnoses, Google sees it as opportunity. Today, Google.org (the philanthropic arm of the Google monster) unveiled Google Flu Trends, a web tool that will track flu outbreaks based on user-generated search terms. http://louissheehan.bravejournal.com/

Flu Trends works because the Google search box is so often the first place people turn at the first sign of a sniffle. The company says Flu Trends could alert users to flu activity in their area up to two weeks ahead of traditional systems like emergency room reports.

The New York Times reports:

To develop the service, Google’s engineers devised a basket of keywords and phrases related to the flu, including thermometer, flu symptoms, muscle aches, chest congestion and many others. Google then dug into its database, extracted five years of data on those queries and mapped the data onto the C.D.C.’s reports of “influenza-like illness,” which the agency compiles based on data from labs, health care providers, death certificates and other sources. http://louissheehan.bravejournal.com/ Google found an almost perfect correlation between its data and the C.D.C. reports.

Flu Trends gives you a day-to-day report on flu activity across the country, so you’ll know to stay in bed if your state turns red (level: intense)—in which case, Google will still be there for you, letting you stargaze and navel-gaze from the comfort of your own home. It won’t make you chicken soup…yet. Louis J. Sheehan, Esquire

dongtan 773.34 Louis J. Sheehan, Esquire

We’ve heard for years how our current way of life is unsustainable and that it shouldn’t be used as a model for developing nations. Well, it appears that China accepts that premise and is prepared to chart its own course – at least for a share of its newly urbanizing masses.

Leaders of the world’s largest population are currently planning the creation of at least 10 eco-cities – large communities where green living will not only be preached but practiced. If any of these cities accomplishes even a fraction of what’s on the drawing board, they will be years ahead of anything in the United States or elsewhere in the West.http://louis9j9sheehan.blog.com

Indeed, America’s urban planners may one day be studying at sustainability institutes, like the one to be created in Dongtan, China. At least that’s the lesson Peter Head offered an audience at New York University, Friday night.

Head directs a London-based sustainable-building unit for Arup. This consulting company designs and engineers construction projects around the world. A little less than three years ago, the Shanghai Industrial Investment Corp. commissioned Arup to “plan the world’s first sustainable city”. Those are Arup’s words, not mine. But that his eco-city description looks pretty apt, at least on paper, based on Head’s presentations about Dongtan, last week (at events associated with the World Science Festival).

To be sited on the eastern edge of an island associated with Shanghai, Dongtan is supposed to be ready for occupancy within the next two years. Only about four meters above sea level, Dongtan will be surrounded on three sides by water and border prized wetlands.

Plans for the new community – initially with a population of 80,000, but eventually with one perhaps six times that size – call for the sole use of zero-emissions vehicles, which means ones that are all-electric or run on hydrogen-powered fuel cells. Wastes throughout the community will be recycled. Electricity will be powered “entirely from renewables,” Head said –everything from solar energy to the burning of rice husks or trash. Carbon-dioxide emissions from burning will be captured and used to help fuel the growth of food crops. Waste heat from the power plants will be piped throughout the community to warm homes or other facilities. Rainwater and sewage will be captured, cleaned, and re-used.

Foods will be grown close to the town. Everyone’s home or business is supposed to be accessible from public transportation (buses, streetcars, or water taxis) that is no more than a 7-minute walk away. Healthcare centers, cultural venues, leisure parks and greenways are being planned to pepper the community so that people don’t have to leave the island for fun, education, doctors, or employment.

In 1900, Head says, there were eight hectares of land for every person on the planet. Today the patch of land that supports each of us has shrunk by 75 percent, partly owing to pollution and partly due to population growth. Clearly, the fossil-fuel-based lifestyle that characterized the past century can’t be relied upon much longer, he argues.

Apparently, it’s a point that not lost upon Chinese-development officials either. Which is why they’re sinking big bucks into foreign consultants and engineers to help them create a new paradigm for urbanization, Head says. Big Red’s eco-cities will become test beds for new technologies, new systems for delivering goods and services, and catalyzing social change.

Head says Chinese officials believe they can design new urban centers that will take their citizens straight “from the agricultural to the ecological age.”

We’ll see. It’s a bold experiment. There are bound to be big hiccups along the way as good ideas and inflation swell budgets and tax the patience of designers. We’ll also see how comfortable people are becoming guinea pigs for a whole new era of social engineering.

Don’t get me wrong, I think the idea of these eco-cities is long overdue. I might even volunteer to live in one if it were cloned on American soil and Science News would allow me to telecommute. But in China? I don’t know.

Pollution wafts a long way and even if the new eco-cities are clean, their neighbors’ emissions could keep the regional air chokingly dirty for years to come. Moreover, Dongtan is basically out in the sea – courting a drowning if sea levels rise (I didn’t see dike development as a key feature in Dongtan’s landscape).

But I commend China for even getting its feet wet in this arena. And the idea that there will be integrated sustainability institutes to evaluate what’s going right – or wrong – and how things could be improved: That’s just inspired. http://louis9j9sheehan.blog.com

We don’t have long to wait to see if this concept blossoms or fizzles. Shanghai hosts the world’s fair – or Expo – in 2010 and Dongtan is supposed to showcase green development features for Asia and elsewhere.Louis J. Sheehan, Esquire

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When Comet 8P/Tuttle passed close to Earth early this year, astronomers took its portrait with the Arecibo radio telescope in Puerto Rico. To their surprise, the radar images have revealed that the comet consists of two chunks that appear to be held together by a narrow neck of material.

The portrait suggests that the body is the first known example of a comet that is a contact binary. Researchers aren’t sure how the structure formed.

John Harmon of Arecibo Observatory reported the findings on October 11 in Ithaca, N.Y., at the annual meeting of the American Astronomical Society’s Division for Planetary Sciences.

Collisions that might form a binary are much more common among the rocky bodies in the asteroid belt than in the much more remote and sparsely populated regions of the solar system where comets originate.

“To make a [comet] contact binary implies a formation mechanism that we don’t understand, but we’re guessing would be different than that in the asteroid belt,” says study collaborator Mike Nolan of Arecibo.

It’s possible, he says, that 8P/Tuttle broke into pieces sometime in the past when it neared the sun — the comet make its closest approach every 13.5 years — and its surface warmed.

Such fragmenting is well known among comets, but in this case some of the pieces, which travel on similar but not identical orbits, would have had to reassemble. “Our understanding of how you make comets must now include the possibility of making an object” like 8P/Tuttle, says Nolan.

Observations using the Hubble Space Telescope and the Spitzer Space Telescope show that one the comet’s chunks is 5.6 kilometers in diameter and the other is 2.4 kilometers in diameter, Philippe Lamy and Olivier Groussin of the Astrophysics Laboratory in Marseilles, France, reported.

hybrid 883300.33e Louis J. Sheehan, Esquire

Louis J. Sheehan, Esquire. A gene of mixed evolutionary pedigree may have transformed mammalian reproduction, leading to the evolution of apes and humans.

Analyses of genetic data from a variety of mammals show that this gene, called Tre2, occurs only in apes and people, say graduate student Charles A. Paulding and geneticist Daniel A. Haber, both of Massachusetts General Hospital Cancer Center in Charlestown, and anthropologist Maryellen Ruvolo of Harvard University. http://louis_j_sheehan.today.com

Although other investigators first identified Tre2 about 10 years ago, the gene's evolutionary origins were unknown. Tre2 represents a hybrid, or so-called chimeric version, of two genes that fused together, Paulding and his coworkers assert in an upcoming Proceedings of the National Academy of Sciences. The DNA sequence of roughly half of Tre2 closely corresponds to an evolutionarily ancient gene still possessed by many species of mammals, the scientists hold. The rest of Tre2's sequence matches a more recently evolved gene found only in monkeys, apes, and people.

Fusion of the two genes must have occurred after the arrival of a common ancestor of apes and humans, between 21 million and 33 million years ago, the scientists theorize.

Although Tre2's two precursor genes both translate into proteins that act on many tissues, Tre2's corresponding protein affects only the testes, Paulding's group finds. If further research implicates Tre2 in sperm function, it will support the possibility that the gene's emergence created reproductive barriers between ancient creatures that did and didn't have it.

In other words, Tre2 may have influenced the evolution of species ancestral to modern apes and humans. http://louis_j_sheehan.today.com

"Tre2 by itself isn't a magic bullet that explains the evolution of ape and human ancestors," says Ruvolo. "This is the beginning of a new line of research into many chimeric genes that characterize different primate species."

Chimeric genes apparently form as part of a DNA-reshuffling process. Many genes contain two or more segments that produce specific proteins.

For instance, unlike its genetic precursors, part of Tre2 codes for a protein that influences cell proliferation, even in animals that don't possess Tre2.

"Many genes have hybrid histories," comments geneticist Pascal Gagneux of the University of California, San Diego. "This interesting new finding is the beginning of an avalanche of information from different laboratories searching for genes specific to humans and apes." When the complete sequence of the chimp genome becomes available later this year, scientists will be able to expand their hunt for hybrid genes, Ruvolo adds.