Monday, September 28, 2009

PROMISING LINK BETWEEN WARMTH, BETTER MOODS PROBED BY CU-BOULDER SCIENTIST

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The University of Colorado at Boulder scientist who discovered that playing in the dirt might ease depression is probing the link between higher temperatures and elevated mood.

Christopher Lowry sees relationships between both lines of inquiry -- researching the link between the immune system and the neurotransmitter serotonin and probing the link between temperature and serotonin.

The upshot is potentially significant. Understanding these mechanisms might help scientists craft better treatments for depression and other mood disorders, he says.

Lowry, an assistant professor of integrative physiology, believes the area of research is promising. So does the National Science Foundation, which recently granted Lowry a $500,000 Faculty Early Career Development Award, a prestigious honor also called the CAREER Award, to continue his study of the role of temperature in mood.

"Whether lying on the beach in the midday sun on a Caribbean island, grabbing a few minutes in the sauna or spa after work or sitting in a hot bath or Jacuzzi in the evening, we often associate feeling warm with a sense of relaxation and well-being," Lowry writes in a recent edition of the Journal of Psychopharmacology.

"Intuitively, we all understand that temperature affects our mood," Lowry said. But a link has not been clearly defined. "So that's what we're going after."

Virtually all antidepressant drugs activate the serotonin system. Lowry's research group noted studies from the 1970s showing that warming a small piece of skin in rats caused increased activity in an area of the brain with serotonin-producing neurons. "So then we had a potential pathway," he said.

Lowry's lab has been a world leader in demonstrating that there are different subpopulations of serotonin-producing neurons, some associated with anxiety, others with panic, immune activation and antidepressant-like effects.

And while scientists know that serotonin is related to mood, appetite and aggression, they don't know exactly how the substance is involved. The same is true of antidepressants such as Prozac and other selective serotonin reuptake inhibitors.

"It's a complete black box how these drugs work, which I think many people might find surprising," Lowry says. "We think that if we understood what makes these serotonin neurons different from other neurons that we would then be in a position to develop rational new therapies for treatment of depression."

Several clues suggest a connection between temperature and mood, he says. People who are depressed often experience altered temperature cycles. Virtually all antidepressants can cause sweating, a thermoregulatory cooling mechanism typically triggered when a person gets warm.

This system may be activated by exercise. When you exercise, body temperatures rise, and you sweat. "That very likely involves some of the mechanisms that we're studying," Lowry says.

Several studies have shown that regular exercise has an antidepressant effect. "So they have studied exercise, but they haven't studied temperature change, which is a component of exercise."

Serotonin neurons can be activated by warm temperature externally, via the skin, and internally. The calming effect of body warmth seems to occur only up until the temperature becomes hazardous, around 104 degrees Fahrenheit. "So we think there's a link between the system that cools the body and a sense of relaxation."

University of Colorado at Boulder

ELECTRONIC NOSE SNIFFS OUT TOXINS

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Imagine a polka-dotted postage stamp-sized sensor that can sniff out some known poisonous gases and toxins and show the results simply by changing colors.

Support for the development and application of this electronic nose comes from the National Institute of Environmental Health Sciences, part of the National Institutes of Health. The new technology is discussed in this month's issue of Nature Chemistry and exemplifies the types of sensors that are being developed as part of the NIH Genes, Environment and Health Initiative (GEI) (http://www.gei.nih.gov/index.asp).

Once fully developed, the sensor could be useful in detecting high exposures to toxic industrial chemicals that pose serious health risks in the workplace or through accidental exposure. While physicists have radiation badges to protect them in the workplace, chemists and workers who handle chemicals do not have equivalent devices to monitor their exposure to potentially toxic chemicals. The investigators hope to be able to market the wearable sensor within a few years.

"The project fits into the overall goal of a component of the GEI Exposure Biology Program that the NIEHS has the lead on, which is to develop technologies to monitor and better understand how environmental exposures affect disease risk," said NIEHS Director Linda Birnbaum, Ph.D. "This paper brings us one step closer to having a small wearable sensor that can detect multiple airborne toxins."

The paper's senior author is Kenneth S. Suslick, Ph.D., the M.T. Schmidt Professor of Chemistry at the University of Illinois at Urbana-Champaign. Suslick and his colleagues have created what they refer to as an optoelectronic nose, an artificial nose for the detection of toxic industrial chemicals (TICs) that is simple, fast, inexpensive, and works by visualizing colors.

"We have a disposable 36-dye sensor array that changes colors when exposed to different chemicals. The pattern of the color change is a unique molecular fingerprint for any toxic gas and also tells us its concentration," said Suslick. "By comparing that pattern to a library of color fingerprints, we can identify and quantify the TICs in a matter of seconds."

The researchers say older methods relied on sensors whose response originates from weak and highly non-specific chemical interactions, whereas this new technology is more responsive to a diverse set of chemicals. The power of this sensor to identify so many volatile toxins stems from the increased range of interactions that are used to discriminate the response of the array.

To test the application of their color sensor array, the researchers chose 19 representative examples of toxic industrial chemicals. Chemicals such as ammonia, chlorine, nitric acid and sulfur dioxide at concentrations known to be immediately dangerous to life or health were included. The arrays were exposed to the chemicals for two minutes. Most of the chemicals were identified from the array color change in a number of seconds and almost 90 percent of them were detected within two minutes.

The laboratory studies used inexpensive flatbed scanners for imaging. The researchers have developed a fully functional prototype handheld device that uses inexpensive white LED illumination and an ordinary camera, which will make the whole process of scanning more sensitive, smaller, faster, and even less expensive. It will be similar to a card scanning device.

"One of the nice things about this technology is that it uses components that are readily available and relatively inexpensive," said David Balshaw, Ph.D., a program administrator at the NIEHS. "Given the broad range of chemicals that can be detected and the high sensitivity of the array to those compounds, it appears that this device will be particularly useful in occupational settings."

(Photo: NIH)

The National Institutes of Health

SPACE-RELATED RADIATION RESEARCH COULD HELP REDUCE FRACTURES IN CANCER SURVIVORS

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A research project looking for ways to reduce bone loss in astronauts may yield methods of improving the bone health of cancer patients undergoing radiation treatment.

It is well documented that living in the microgravity environment of space causes bone loss in astronauts, but until recently, little was known about the effects of space radiation on bones. Dr. Ted Bateman leads a project funded by the National Space Biomedical Research Institute (NSBRI) to understand radiation-induced bone loss and to determine which treatments can be used to reduce that loss and lower the risk of fractures.

“Our studies indicate significant bone loss at the radiation levels astronauts will experience during long missions to the moon or Mars,” said Bateman, a member of NSBRI’s Musculoskeletal Alterations Team.

Bateman, an associate professor of bioengineering at Clemson University, and colleagues at Clemson and Loma Linda University have discovered in experiments with mice that bone loss begins within days of radiation exposure through activation of bone-reducing cells called osteoclasts. Under normal conditions, these cells work with bone-building cells, called osteoblasts, to maintain bone health.

“Our research challenges some conventional thought by saying radiation turns on the bone-eating osteoclasts,” Bateman said. “If that is indeed the case, existing treatments, such as bisphosphonates, may be able to prevent this early loss of bone.”

Bisphosphonates are used to prevent loss of bone mass in patients who have osteoporosis or other bone disorders.

Even though the research is being performed to protect the health of NASA astronauts, cancer patients, especially those who receive radiation therapy in the pelvic region, could benefit from the research.

“We know that older women receiving radiotherapy to treat pelvic tumors are particularly vulnerable to fracture, with hip fracture rates increasing 65 percent to 200 percent in these cancer patients,” said Bateman. “Hip fractures are very serious; nearly one in four patients who fracture a hip will not survive a year. A large number of surviving patients will require long-term care. More than 80 percent of the patients will not be able to walk unaided or will not be back to pre-fracture activity levels after a year.”

Once a person loses bone, their long-term fracture risk depends on their ability to recover lost bone mass. For older cancer patients, early introduction of bisphosphonates and other forms of treatment could help greatly since the process of regaining bone mass can be more difficult due to lower activity levels.

Clemson’s Dr. Jeff Willey is a collaborator with Bateman and the lead investigator of an NSBRI-funded project looking at the cellular mechanisms involved in radiation-induced bone loss. He said the bone loss in the spaceflight-related experiments has occurred quickly and cell physiology has changed.

“If we expose mice to a relatively low dose of radiation, the cells that break down bone are turned on several days after exposure,” he said. “After radiation exposure, osteoclasts appear to have a different shape. They get flatter, and there are certainly more of them.”

The mice used in the research have received the amount of radiation exposure that is expected to occur during a lengthy mission to the moon or Mars. The amount is much less than what cancer patients receive during treatment. For example, patients receiving radiation treatment in the pelvic region can receive doses up to 80 gray over a six- to eight-week period, with the hip receiving up to 25 gray. Astronauts are likely to receive about 0.5 to 1 gray during a long-duration lunar or martian mission.

Astronauts are at risk of radiation exposure from two sources. The first is proton radiation from the sun. The second, and less understood type, is galactic cosmic radiation from sources outside the galaxy. Galactic cosmic rays and protons would be the source of radiation damage for astronauts during a mission to Mars.

Marcelo Vazquez, NSBRI’s senior scientist for space radiation research, said Bateman’s project and other NSBRI radiation projects will influence spacecraft design and mission planning. “The research will help to define the radiation risks for astronauts during long-term missions,” Vazquez said. “This will lead to strategies for shielding and medical countermeasures to protect against exposure.”

Bateman’s NSBRI work is leading to other studies. “We have been able to initiate a couple of clinical trials with cancer patients to determine if what we are seeing in mice corresponds with bone loss in humans. Preliminary results in these trials show rapid declines in bone mass and strength,” Bateman said.

(Photo: Patrick Wright/Clemson University)

National Space Biomedical Research Institute

NEW NASA TEMPERATURE MAPS PROVIDE 'WHOLE NEW WAY OF SEEING THE MOON'

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NASA's Lunar Reconnaissance Orbiter (LRO), an unmanned mission to comprehensively map the entire moon, has returned its first data. One of the seven instruments aboard, the Diviner Lunar Radiometer Experiment, is making the first global survey of the temperature of the lunar surface while the spacecraft orbits some 31 miles above the moon.

Diviner has obtained enough data already to characterize many aspects of the moon's current thermal environment. The instrument has revealed richly detailed thermal behavior, throughout both the north and south polar regions, that extends to the limit of Diviner's spatial resolution of just a few hundred yards.

"Most notable are the measurements of extremely cold temperatures within the permanently shadowed regions of large polar impact craters in the south polar region," said David Paige, Diviner's principal investigator and a UCLA professor of planetary science. "Diviner has recorded minimum daytime brightness temperatures in portions of these craters of less than -397 degrees Fahrenheit. These super-cold brightness temperatures are, to our knowledge, among the lowest that have been measured anywhere in the solar system, including the surface of Pluto."

"After decades of speculation, Diviner has given us the first confirmation that these strange, permanently dark and extremely cold places actually exist on our moon," said science team member Ashwin Vasavada of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Their presence greatly increases the likelihood that water or other compounds are frozen there. Diviner has lived up to its name."

These observations, made during Diviner's "commissioning phase," provide a snapshot in time of current polar temperatures that will evolve with the lunar seasons.

"It is safe to conclude that the temperatures in these super-cold regions are definitely low enough to cold-trap water ice, as well as other more volatile compounds, for extended periods," Paige said. "The existence of such cold traps has been predicted theoretically for almost 50 years. Diviner is now providing detailed information regarding their spatial distribution and temperatures."

Diviner's thermal observations represent one component of the LRO's strategy for determining the nature and distribution of cold-trapped water ice in the lunar polar regions. Future comparisons between Diviner data, physical models and other polar data sets may provide important scientific conclusions regarding the nature and history of the moon's polar cold traps and any cold-trapped volatile materials they contain, Paige said.

The moon's surface temperatures are among the most extreme of any planetary body in the solar system. Noontime surface temperatures near the lunar equator are hotter than boiling water, while nighttime surface temperatures on the moon are almost as cold as liquid oxygen. It has been estimated that near the lunar poles, in areas that never receive direct sunlight, temperatures can dip to within a few tens of degrees of absolute zero.

Data accumulated by Diviner during August and the first half of September indicate that equatorial and mid-latitude daytime temperatures are 224 degrees Fahrenheit, and then decrease sharply poleward of 70 degrees north latitude. Equatorial and mid-latitude nighttime temperatures are -298 degrees Fahrenheit, and then decrease poleward of 80 degrees north latitude. At low and mid-latitudes, there are isolated warmer regions with nighttime temperatures of -208 degrees Fahrenheit.

"These correspond to the locations of larger, fresh impact craters that have excavated rocky material that remains significantly warmer than the surrounding lunar soil throughout the long lunar night," Paige said.

The thermal behavior at high latitudes contrasts sharply with that of the equatorial and mid-latitudes. Close to the poles, both daytime and nighttime temperatures are strongly influenced by local topography, and the thermal outlines of many partially illuminated impact craters are apparent.

"Getting a look at the first global thermal maps of the lunar surface is a whole new way of seeing the moon," Paige said.

NASA's LRO launched June 18. Diviner has been mapping the moon continuously during the LRO commissioning phase. Since the instrument was first activated on July 5, it has acquired more than 8 billion calibrated radiometric measurements and has mapped almost 50 percent of the surface area of the moon.

"The performance of the instrument has been excellent, and closely matches our predictions," said instrument engineer Marc Foote of JPL.

"We have already accumulated an enormous amount of high-quality data," Paige said.

There are large gaps between Diviner's individual ground tracks at the equator, but in the polar regions, the ground tracks overlap to create continuous high-resolution maps. During the commissioning phase, the plane of the LRO orbit moved from 5:40 to 1:10 a.m. and p.m., on the night side and day side, respectively. It will take about six months for LRO’s orbit to sample the full range of lunar local times.

In addition to mapping the moon, Diviner executed a series of specialized calibration sequences during the commissioning phase. These included scans of the "limb," or visible edge of the moon to better define the instruments' fields of view and an infrared panorama of a portion of the LRO spacecraft, as well as infrared scans of the Earth from lunar orbit, which are presently being analyzed.

"Diviner has been put through her paces and has executed our commands brilliantly," said JPL scientist and lead observational sequence designer Benjamin Greenhagen. "Diviner's operations have run very smoothly."

During the course of LRO's mapping mission, Diviner will map the entire surface of the moon at high resolution to create the first global picture of the current thermal state of the moon and its daily and seasonal variability.

The moon's extreme temperature environment is of interest to future human and robotic explorers, especially if they plan to visit the moon for extended periods. Detailed thermal maps of the moon can also yield information regarding the locations of rocky areas that may be hazardous to landing vehicles and details for mapping compositional variations in lunar rocks and soils. In the moon's polar regions, temperature maps also point to the locations of cold traps where water ice and other volatile materials may have accumulated. Mapping the locations of these lunar cold traps and searching for the presence of frozen water are among the main goals of the LRO mission.

Diviner is operated by the California Institute of Technology Jet Propulsion Laboratory (JPL), which designed and built the instrument.

Diviner determines the temperature of the moon by measuring the intensity of infrared radiation emitted by the lunar surface. The hotter the surface, the greater the intensity of emitted infrared radiation. Diviner measures infrared radiation in seven infrared channels that cover an enormous wavelength range, from 7.6 to 400 microns. Diviner is the first instrument designed to measure the full range of lunar surface temperatures, from the hottest to the coldest. Diviner also includes two solar channels (channels 1 and 2) that measure the intensity of reflected solar radiation.

(Photo: NASA/GSFC/UCLA)

UCLA

ARCTIC SEA ICE REACHES MINIMUM EXTENT FOR 2009, THIRD LOWEST EVER RECORDED

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The Arctic sea ice cover appears to have reached its minimum extent for the year, the third-lowest recorded since satellites began measuring sea ice extent in 1979, according to the University of Colorado at Boulder's National Snow and Ice Data Center.

While this year's September minimum extent was greater than each of the past two record-setting and near-record-setting low years, it is still significantly below the long-term average and well outside the range of natural climate variability, said NSIDC Research Scientist Walt Meier. Most scientists believe the shrinking Arctic sea ice is tied to warming temperatures caused by an increase in human-produced greenhouse gases being pumped into Earth's atmosphere.

Atmospheric circulation patterns helped the Arctic sea ice spread out in August to prevent another record-setting minimum, said Meier. But most of the 2009 September Arctic sea ice is thin first- or second-year ice, rather than thicker, multi-year ice that used to dominate the region, said Meier.

The minimum 2009 sea-ice extent is still about 620,000 square miles below the average minimum extent measured between 1979 and 2000 -- an area nearly equal to the size of Alaska, said Meier. "We are still seeing a downward trend that appears to be heading toward ice-free Arctic summers," Meier said.

CU-Boulder's NSIDC will provide more detailed information in early October with a full analysis of the 2009 Arctic ice conditions, including aspects of the melt season and conditions heading into the winter ice-growth season. The report will include graphics comparing 2009 to the long-term Arctic sea-ice record.

University of Colorado

IMPACT OF RENEWABLE ENERGY ON OUR OCEANS MUST BE INVESTIGATED

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Scientists from the Universities of Exeter and Plymouth are calling for urgent research to understand the impact of renewable energy developments on marine life. The study, now published in the Journal of Applied Ecology, highlights potential environmental benefits and threats resulting from marine renewable energy, such as off-shore wind farms and wave and tidal energy conversion devices.

The research highlights the capacity for marine renewable energy devices to boost local biodiversity and benefit the wider marine environment. Man-made structures on the sea bed attract many marine organisms and sometimes become 'artificial reefs', for example, supporting a wide variety of fish. The study also points out that such devices could have negative environmental impacts, resulting from habitat loss, collision risks, noise and electromagnetic fields.

The study highlights the gaps in our understanding of the effects of marine renewable energy devices on the health of our oceans. The team calls for more research to improve our understanding of these threats and opportunities. The researchers also stress the importance of considering the impact on marine life when selecting locations for the installation of marine energy devices.

Corresponding author Dr Brendan Godley of the University of Exeter said: "Marine renewable energy is hugely exciting and it is vital that we explore the potential for it to provide a clean and sustainable energy source. However, to date research into the impact of marine renewable energy on sea life has been very limited. . Our study highlights the urgent need for more research into the impacts of marine renewable energy on marine life. This will involve biologists, engineers and policy-makers working together to ensure we really understand the risks and opportunities for marine life."

Professor Martin Attrill, Director of the University of Plymouth Marine Institute said: "Our paper highlights the need to take a fresh look at the effect marine renewable energy generation has on the environment if we are to deliver a higher proportion of energy from renewable sources and start to combat climate change. We need to have the industry working directly with conservation bodies to plan the next phase of development. We suggest further research could demonstrate the potential of security zones around, for example, wave farms to act as Marine Protected Areas. Therefore, if all stakeholders can work together in a coordinated way we can possibly address two key issues - combating climate change and creating a network of MPAs. We need the research on environmental impact to help move the whole field forward."

(Photo: Dr Matthew Witt, University of Exeter)

Universities of Exeter

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