October 27, 2006, 9:26 PM CT

Vitamin C and Water Healthy for Plastics, Too

Two new laboratory breakthroughs are poised to dramatically improve how plastics are made by assembling molecular chains more quickly and with less waste. Using such environmentally friendly substances as vitamin C or pure water, the two approaches present attractive alternatives to the common plastic manufacturing technique called free radical polymerization (FRP).

"The methods both present novel and complementary ways to dramatically improve efficiency, product control, and cost for the polymer industry," said Andy Lovinger, the National Science Foundation program director who oversees funds for the two projects. "Each of these approaches could have a very significant impact on polymer manufacturing".

Plastics are polymers, long, potentially complex, molecule chains crafted from an array of smaller chemical units. Using FRP, chemical engineers can create the right plastic for a range of applications, such as a specific trim for a car door or soft foam for a pillow.

For some plastics, the building-block molecules do not easily link together. To surmount this problem, scientists from Carnegie Mellon University in Pittsburgh, Pa., devised a process called atom transfer radical polymerization (ATRP), which provides creative ways to coax the chemical subunits into chains. However, this method comes with certain costs, such as the need for a copper catalyst that can become unwanted waste.........

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October 27, 2006, 9:19 PM CT

How Oceans Emit Sulfur Into Atmosphere

Researchers have discovered a bacterial "switch gene" in two groups of microscopic plankton common in the oceans. The gene helps determine whether certain marine plankton convert a sulfur compound to one that rises into the atmosphere, where it can affect the earth's temperature, or remain in the sea, where it can be used as a nutrient.

"This new gene offers a powerful tool to study the question of how these plankton are involved with sulfur exchange between the ocean and atmosphere," said Mary Ann Moran, marine microbial ecologist at the University of Georgia. Moran and her colleagues published their findings in the Oct. 26, 2006, issue of the journal Science.

Much of the sulfur in the atmosphere comes from the surface of oceans, from a compound called dimethlysulfide, or DMS. Marine plankton control how much sulfur rises into the atmosphere by converting a compound called DMSP, or dimethylsulfoniopropionate, to DMS or to sulfur compounds that are not climatically active. Moran and her team discovered a gene that controls whether or not these sea drifters create DMS that rises into the air.

"Isolating and discovering a novel, keystone bacterium from the ocean first, and then sequencing its genome enabled this team to find the genes involved in the DMSP cycle," said Matthew Kane, program director in the National Science Foundation (NSF) Division of Molecular and Cellular Biosciences, which supported the research. "The research has revealed the previously hidden role that marine microbes play in the global sulfur cycle".........

Posted by: Sarah      Permalink         Source

October 27, 2006, 9:02 PM CT

Mate-attracting Chemicals in Silk worms

It's all about "the birds and the bees." And now, "the silkworm moths and the fruit flies".

A chemical ecologist and a genetics researcher at the University of California, Davis, have joined forces to trick fruit flies into thinking that silkworm moths are potential mates.

Groundbreaking research in the labs of chemical ecologist Walter Leal and genetics researcher Deborah Kimbrell shows that genetically engineered fruit flies responded to the silkworm moth scent of a female.

The practical implications of the findings could be widespread. Methods that can attract or repel insects have important applications for agricultural pests and medical entomology. The research could lead to designing better chemicals to attract insects and designing better chemicals to suppress insect communication. That is because insects communicate or smell through their antennae.

Many insect species, including silkworm moths, release sex pheromones or chemical signals to attract a mate. "Silkworm moths utilize smell more strongly than any other senses," said Leal, professor and chair of the Department of Entomology. "Moths keep on the trail of a scent until they find a female".

"We got a very clear response," he said. "Our electrophysiological recordings and direct stimulation testing showed that the transgenic fruit flies definitely responded to the moth pheromone".........

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October 27, 2006, 5:18 AM CT

What Killed Dinosaurs 65 Million Years Ago

Growing evidence shows that the dinosaurs and their contemporaries were not wiped out by the famed Chicxulub meteor impact alone, as per a paleontologist who says multiple meteor impacts, massive volcanism in India and climate changes culminated in the end of the Cretaceous Period.

The Chicxulub impact may have been the lesser and earlier of a series of meteor impacts and volcanic eruptions that pounded life on Earth for more than 500,000 years, say Princeton University paleontologist Gerta Keller and her collaborators Thierry Adatte from the University of Neuchatel, Switzerland, and Zsolt Berner and Doris Stueben from Karlsruhe University in Gera number of.

A final, much larger and still unidentified impact 65.5 million years ago appears to have been the last straw, said Keller, exterminating two-thirds of all species in one of the largest mass extinction events in the history of life. It's that impact - not Chicxulub - that left the famous extraterrestrial iridium layer found in rocks worldwide that marks the impact that finally ended the Age of Reptiles, Keller believes.

"The Chicxulub impact alone could not have caused the mass extinction," said Keller, "because this impact predates the mass extinction".

Keller is scheduled to present that evidence at the annual meeting of the Geological Society of America (GSA) in Philadelphia, on Tuesday, October 24, 2006.........

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October 27, 2006, 5:12 AM CT

Women With Mental Disorders And Mammograms

Women with mental disorders are less likely to have screening mammograms than women without mental illness, although.

the nature of the mental illness does play a role, according to a large study published by Indiana University School of Medicine and Richard Roudebush VA Health Services Center for Excellence researchers in the recent issue of Journal of General Internal Medicine. Prior to this study, little was known about whether the type or severity of mental illness influences receipt of preventive services such as mammograms.

"Although women with mental disorders are less likely to receive mammography than women who do not have mental disorders, we found that both the type and severity of mental illness does influence the receipt of mammograms. Women with psychotic disorders such as schizophrenia are significantly less likely to receive mammograms than women in the general population. However, women with mild depression do not differ markedly. But, as depression severity increases, so does the likelihood that women will not receive needed screening," said senior author Caroline Carney Doebbeling, M.D., M.Sc., associate professor of psychiatry and medicine at the I.U. School of Medicine. She is also a Regenstrief Institute, Inc. research scientist and director of the IU.........

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October 27, 2006, 4:44 AM CT

Gene Target Against Crohn's Disease And Ulcerative Colitis

The discovery by a six-member Inflammatory Bowel Disease (IBD) Genetics Consortium of a genetic risk factor for IBD has been reported in Science Express, the online publication of the journal Science. As per one of the Canadian principal investigators, director of the Laboratory in Genetics and Genomic Medicine of Inflammation at the Montreal Heart Institute, Dr. John D. Rioux, "This discovery may lead to a paradigm shift in our thinking from 'genetics of diseases to genetics of health', especially as concerns Crohn's Disease and Ulcerative Colitis." This discovery was, in part, due to the contributions of the gastroenterologists of the Quebec IBD Genetics Consortium led by Dr. Rioux and Dr. Alain Bitton of the McGill University Health Centre.

Inflammatory bowel disease, or IBD, describes two similar yet distinct conditions called Crohn's disease and ulcerative colitis. These diseases affect the digestive system and cause the intestinal tissue to become inflamed, form sores and bleed easily. Symptoms include abdominal pain, cramping, fatigue and diarrhea.

Crohn's disease may affect the gastrointestinal tract, from the mouth to the anus, and while Crohn's disease can not be cured by drugs or surgery, either may relieve symptoms.

In Canada, an estimated 170,000 Canadian men and women suffer from IBD, most frequently between the ages of 15-25, or 45-55. It is especially difficult for children and young adults since it often affects a person's self-concept. IBD is found throughout the world. However, it appears to be most common in North America and northern Europe; Canada having one of the highest incidence rates of IBD in the world. (1) In the U.S., more than 1 million Americans have Crohn's or colitis.........

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October 27, 2006, 4:33 AM CT

Cracking The Stellar Evolution

Using 3D models run on some of the fastest computers in the world, Laboratory physicists have created a mathematical code that cracks a mystery surrounding stellar evolution.

For years, physicists have theorized that low-mass stars (about one to two times the size of our sun) produce great amounts of helium 3 (³He). When they exhaust the hydrogen in their cores to become red giants, most of their makeup is ejected, substantially enriching the universe in this light isotope of helium.

This enrichment conflicts with the Big Bang predictions. Scientists theorized that stars destroy this ³He by assuming that nearly all stars were rapidly rotating, but even this failed to bring the evolution results into agreement with the Big Bang.

Now, by modeling a red giant with a fully 3D hydrodynamic code, LLNL researchers identified the mechanism of how and where low-mass stars destroy the ³He that they produce during evolution.

They found that ³He burning in a region just outside of the helium core, previously thought to be stable, creates conditions that drive this newly discovered mixing mechanism.

Bubbles of material, slightly enriched in hydrogen and substantially depleted in ³He, float to the surface of the star and are replaced by ³He-rich material for additional burning. In this way the stars destroy their excess ³He, without assuming any additional conditions (like rapid rotation).........

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October 26, 2006, 5:17 AM CT

Moderate Drinking May Boost Memory

In the long run, a drink or two a day may be good for the brain.

Researchers found that moderate amounts of alcohol - amounts equivalent to a couple of drinks a day for a human - improved the memories of laboratory rats.

Such a finding may have implications for serious neurodegenerative diseases like Alzheimer's, said Matthew During, the study's senior author and a professor of molecular virology, immunology and cancer genetics at Ohio State University.

"There is some evidence suggesting that mild to moderate alcohol consumption can protect against diseases like Alzheimer's in humans," said During. "But it's not apparent how this happens".

He and his colleague, Margaret Kalev-Zylinska, a postdoctoral researcher at the University of Auckland, in New Zealand, uncovered a neuronal mechanism that may help explain the link between alcohol and improved memory.

"We saw a noticeable change on the surface of certain neurons in rats that were given alcohol," During said. "This change may have something to do with the positive effects of alcohol on memory".

The researchers presented their findings at the annual Society for Neuroscience conference in Atlanta.

During and Kalev-Zylinska designed a special liquid diet for the rats. One formulation included a low dose of alcohol, comparable to two or three drinks a day for a human, while the other diet included a much higher dose of alcohol, comparable to six or seven drinks a day for a human. A third group of rats was given a liquid diet without alcohol. All animals were given their respective diets daily for about four weeks.........

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October 26, 2006, 5:11 AM CT

Linking Emotions And Memories

Having a child with bottled up emotions isn't a good thing. Psychologists from Case Western Reserve University have found that the range of emotions that children use in play can be used as an indicator of how emotionally charged their memories will be.

Emotions--whether positive or negative--in play offer important information to people working with children about how able they will be at expressing the emotional side of their memories. Accessing emotional memories is important for adjusting to traumas experienced.

Many children are unable to start talking about their emotions or memories with someone new, but watching children play can help child therapists and others working with children gauge how open children might be to talking about the emotions associated with past memories, according to Sandra Russ, Case professor of psychology. She has been studying the emotional side of play and how play benefits children for more than 20 years.

Russ, with Ethan D. Schafer, discusses this discovery in the Creativity Research Journal article, "Affect in Fantasy Play, Emotion in Memories, and Divergent Thinking." In the past, this link between emotions in play therapy and emotions in memories was observed but had not been formally studied in children.........

Posted by: Sean      Permalink         Source

October 26, 2006, 5:00 AM CT

HIV-positive individuals with inadequate care

In a first-of-its-kind study, UCLA researchers have shown that segments of the HIV-infected population who have little to no consistent outpatient medical care -- and yet are most in need of such services -- are overwhelmingly minorities, the poor and substance abusers.

Previous studies had shown minorities, the poor and substance users who were receiving routine medical care for the HIV infection, and whose data could therefore be easily captured in healthcare studies, were likelier to be medically underserved and to die more quickly. But Dr. William Cunningham, and the study's lead author, said UCLA researchers tracked HIV-infected people who were not receiving regular care -- and thus more difficult to find. Often this segment showed up in the medical system in emergency situations.

"As we expected, they are much less likely to get routine outpatient care but more likely to get acute care, when they are at their sickest," said Cunningham, who is professor of medicine in the Division of General Internal Medicine and Health Services Research at the David Geffen School of Medicine at UCLA. "This is just the group that needs to get grassroots outreach service".

For this study, would be published in the recent issue of the journal Medical Care, the researchers compared socio-demographic, clinical and health care utilization characteristics of HIV-infected adults from two samples: 1,286 people from the 2001-02 Targeted HIV Outreach and Intervention Initiative (Outreach) and 2,267 who were interviewed in 1998 for the HIV Costs and Services Utilization Study (HCSUS).........

Posted by: Sean      Permalink         Source