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