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View from the Inside
Human Genome Sequencing
Magnetic Moment
Scintimammography
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This issue...
News in Brief
View from the Inside
Human Genome Sequencing
Magnetic Moment
Scintimammography
People
About
Subscribe Free
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News in Brief
Obesity Linked to Dopamine Levels
Scientists at the Department of Energy's Brookhaven National Laboratory found that dopamine, a brain chemical associated with addiction to cocaine, alcohol, and other drugs, may also play an important role in obesity. The findings were published in the February 3, 2001 issue of The Lancet.
Obese people may overeat compulsively in a bid to stimulate the "reward circuit" in the brain, for much the same reason that people take "feel good" drugs like cocaine. Dopamine, a neurotransmitter naturally produced in the brain, plays a key role in the function of the reward circuit and in modifying mental and physical activity.
 | PET scan comparison of obese to normal-weight subjects (click to see larger version). |
Drug addicts have fewer dopamine receptors than normal subjects, resulting in low dopamine activity. The drugs they use increase the level of dopamine activity in the brain, stimulating the reward circuit and leading to the drug "high." Scientists at Brookhaven found that obese subjects also had fewer dopamine receptors than normal-weight subjects. They also found an inverse relation between the number of dopamine receptors and the subjects' body mass indexthat is, the more obese the individual, the fewer dopamine receptors they had.
"The results from this study suggest that strategies aimed at improving dopamine function might be beneficial in the treatment of obese individuals," says physician Gene-Jack Wang, the lead scientist on the study. Although a variety of dopamine-enhancing drugs are available, many have undesirable side effects. As an alternative to drugs, the researchers point out a natural, safe, and inexpensive method of increasing dopamine levels in the brainexercise.
The Brookhaven study was supported by DOE's Office of Science, Division of Biological and Environmental Sciences.
Media contacts: Dennis Tartaglia, (212) 481-7000, dennist@mbooth.com
; Karen McNulty Walsh, (631) 344-8350, kmcnulty@bnl.gov.
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How Ritalin Works
New research on the drug Ritalin, reported in the January 15 issue of the Journal of Neuroscience, shows for the first time how the drug acts in the human brain and why it is so effective.
Ritalin, a drug prescribed to millions of American children with Attention Deficit Hyperactivity Disorder (ADHD) each year, is the subject of a new study at the Department of Energy's Brookhaven National Laboratory. The Brookhaven study, on humans, indicates that Ritalin, given at doses commonly used to treat children with ADHD, significantly increases levels of dopamine in the brain, thereby stimulating attention and motivational circuits that enhance one's ability to focus and complete tasks.
Earlier animal and limited human studies had indicated that Ritalin interferes with the recycling of dopamine within the brain by blocking dopamine transporters. However, since these earlier studies involved injection of much higher doses of Ritalin, it was unclear whether the drug would increase extracellular dopamine at doses used therapeutically for children.
 | These three sets of brain scans from a young adult given a placebo (top) and two different doses of methylphenidate, or Ritalin (bottom), show the ability of Ritalin to block the transporter "gates" by which the brain chemical dopamine returns to its home cell after sending a pleasure signal. Red indicates more dopamine transporters available; blue is least transporters available.
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"We now know that by increasing the levels of extracellular dopamine, you can activate these motivational circuits and make the tasks that children are performing seem much more exciting," said Volkow. "By raising that level of interest, you can significantly increase the ability of the child to focus on the task."
Volkow added that Ritalin also works to suppress "background" firing of neurons not associated with task performance, allowing the brain to transmit a clearer signal. "Random activation of other cells can distract you, and children with ADHD are easily distracted," she said. "Ritalin suppresses that background firing and accentuates the specific activation, basically increasing the signal-to-noise ratio and increasing a child's ability to focus."
Volkow is now planning a follow-up study of subjects suffering from ADHD. "We hypothesize that we will find that ADHD sufferers have decreased function of dopamine circuits and are therefore easily distracted," she said. "The effect of Ritalin should be to normalize these levels, allowing them to focus and pay attention."
The research was funded by DOE's Office of Energy Research and by the National Institute on Drug Abuse, part of the National Institutes of Health.
Media contacts: Peter Genzer, Brookhaven National Laboratory, 631 344-3174, genzer@bnl.gov
; Mona S. Rowe, Brookhaven National Laboratory, 631 344-5056, mrowe@bnl.gov
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Fusion in a Pop Can
Researchers at the Department of Energy's Los Alamos National Laboratory and the U.S. Air Force Research Laboratory in Albuquerque, New Mexico, are investigating a way to create fusion energy in a cylinder roughly the size of a soda can.
Magnetized Target Fusion (MTF) research shows the potential for producing smaller fusion energy sources at a cost that is far less than current approaches.
"The primary benefit of MTF is that it requires simpler, smaller and considerably less expensive experimental systems than either magnetic or inertial fusion," said Glen Wurden, a Los Alamos scientist who leads one of the MTF teams.
"It is a qualitatively different approach to fusion with the potential for truly low-cost development. This means that fusion experiments and testing facilities might conceivable be built that cost in the tens of million dollar range, rather than in the billion dollar range."
In a process roughly analogous to that of a diesel engine, which compresses fuel to a state where it burns more readily, MTF uses a magnetized fusion fuel in the form of an electrically neutral, high-temperature ionized gasa plasmathat is pre-heated before being injected into a soda-can-sized aluminum cylinder.
The cylinder and its contents are then quickly compressed by driving a powerful electrical current through the wall of the cylinder. As the fast-moving solid metal wall compresses the fuel, it burns in a few millionths of a second at pressures that are millions of times greater than that of the Earth's atmosphere.
Within this mass of super-compressed, high-density plasma, scientists hope to produce tiny amounts of fusion energythe same kind of energy that fuels the sun.
MTF is a collaboration between Los Alamos, the U.S. Air Force Research Laboratory and other laboratories with funding provided by the Department of Energy's Office of Fusion Energy Sciences.Todd Hanson
Media Contact: Todd A. Hanson, LANL, (505) 665-2085, tahanson@lanl.gov
Research Contacts: Glen Wurden, LANL, Plasma Physics, wurden@lanl.gov
; Richard E. Siemon, LANL, rsiemon@lanl.gov
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Knowledge is Power...and Power Keeps the Lights On!
Earlier this year, the new Bush Administration extended the Clinton Administration orders requiring out-of-state power producers to sell surplus electricity to California. That order kept power flowing into California from the Pacific Northwest.
Power is not the only thing the Pacific Northwest is sharing with California. In the age of electricity deregulation, information has become equivalent to power. Providers who know of potential outage conditions often can take action to ensure "the lights stay on" if they have the right information.
A system developed by the Department of Energy's Pacific Northwest National Laboratory and the Bonneville Power Administration will soon provide this key information to California power providers that are challenged by increased loads and decreased supply.
The system, called WAMS for Wide Area Measurement System, continuously monitors grid performance across the Western power system. It provides operators with high-quality data and analysis tools to detect impending grid emergencies or to mitigate grid outages.
WAMS data access and toolsets are being provided to California's Independent System Operator, which manages wholesale power delivery in that state. Funding is being provided by the California Energy Commission and DOE through the Consortium for Electric Reliability
Technologies. The Pacific Northwest National Laboratory is a consortium member. WAMS' initial development was supported by DOE and the Electric Power Research Institute.
DOE recently named WAMS one of its top 100 energy innovations. More information is available on DOE's Energy 100 website.
Contact: Greg Koller, PNNL, (509) 375-3776, greg.koller@pnl.gov
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Radiation Resistant "Superbug"
Deinococcus radiodurans has been called "Superbug," "the world's toughest microbe," and "Conan the Bacterium" because it is the most radiation resistant microorganism yet reported. This unique attribute may someday make it the microbe of choice for remediating highly radioactive waste.
Scientists at the Department of Energy's Pacific Northwest National Laboratory (PNNL) reported the first evidence that Deinococcus radiodurans can naturally reduce radioactive and metal contaminants such as uranium, technetium, and chromium.
Until recently, D. radiodurans was believed to have a strictly aerobic metabolism (needing oxygen) and would be unable to reduce metals, which requires a process with strictly anaerobic conditions (absence of oxygen). As part of DOE's Natural and Accelerated Bioremediation Research (NABIR) program, Jim Fredrickson and colleagues at PNNL and the Uniformed Services University of the Health Sciences in Bethesda, Maryland, discovered that this microbe can enzymatically reduce radionuclides and metal contaminants in the absence of air. When provided a simple carbon and energy source, such as lactate, D. radiodurans produced relatively insoluble and immobile forms of the contaminants.
DOE faces challenging cleanup problems at more than 18 facilities across the U.S. resulting from the production of weapons-grade nuclear materials between 1945 and 1986. Among the most common inorganic contaminants at these sites are the elements uranium, plutonium, technetium, and chromium. All of these are less mobile when reduced by microorganisms. However, some contaminated sediments and soils at DOE sites, particularly beneath leaking waste storage tanks, can have radiation levels that exceed those tolerated by most microorganisms. D. radiodurans can withstand radiation levels up to 1.5-million rads500 rads is lethal to humans. It might be the only known microorganism that can survive such conditions and may someday be used to remediate highly radioactive waste.
Microbes of the deinococci family appear to be widely distributed in soils and have been routinely isolated from organically rich as well as dry, nutrient-poor environments. Therefore, it is possible that deinococci capable of reducing metal and radionuclides may be native to some contaminated environments. To begin the useful process of reducing radioactive metals, D. radiodurans requires the presence of humic acids, which can be added if none occur naturally at a site.
Additional research is required to better understand the ecology of the deinococci and the potential for naturally occurring strains to reduce metals. These studies were supported by DOE's Office of Biological and Environmental Research, Life Sciences Division, and the Natural and Accelerated Bioremediation Research (NABIR) program.James R. Weber
Research contacts: Jim Frederickson, PNNL, (509) 376-7063, jim.frederickson@pnl.gov
Richard Smith, PNNL, (509) 376-0723, dick.smith@pnl.gov
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First Results Published from B-Factory
The recently completed B-factory at the Stanford Linear Accelerator Center (SLAC), a major addition to the Nation's high energy physics capability, has published some very interesting first results.
The BaBar detector collaboration, which uses the asymmetric colliding beams from PEP-II, has released the most precise results to date on the behavior of short-lived subatomic particles called B mesons. The BaBar detector measures subtle differences between the decays of B mesons and those of their antimatter counterparts, or anti-B mesons, with a primary goal of explaining why our universe contains more matter than antimatter. The collaboration's results are about twice as accurate as previously published values, and this new information is expected to provide important clues toward this goal.
The BaBar detector was designed and built by a team of 550 physicists from nine countries, and these tantalizing results are the culmination of more than a decade of effort. The precision of the BaBar result was made possible by the excellent performance of the B-factory's PEP-II collider. The collider, built in collaboration with the Department of Energy's Lawrence Berkeley and Lawrence Livermore National Laboratories, is the machine that collides the beams of electrons and positrons that are studied by the BaBar detector.
Contact: Michael Riordan, SLAC, (650) 926-3990, michael@slac.stanford.edu
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DOE Human Subjects Research Database on the World Wide Web
The FY 2000 update of the DOE Human Subjects Research Database (HSRD) is now on the World Wide Web (http://www.eml.doe.gov/hsrd/). HSRD is a comprehensive database containing information on all research projects that involve human subjects and that were either funded by DOE, conducted at DOE facilities, or performed by DOE personnel during FY 2000. The FY 2000 database profiles 300 research projects at 44 research facilities and includes a variety of activities ranging from actual experimentation using human volunteers to gathering information using simple questionnaires or existing information such as medical records. The Environmental Measurements Laboratory (EML) maintains the database for the Office of Biological and Environmental Research within the Office of Science.
Contact: Susan Rose, Office of Science, (301) 903-4731, Susan.L.Rose@science.doe.gov
; Richard Larsen, Environmental Measurements Laboratory, (212) 620-3524, larsenr@eml.doe.gov
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