New technique finds Jupiter-like exoplanet
PASADENA, Calif., May 28 (UPI) -- The U.S. space agency says a new planet-hunting technique has recorded its first discovery -- a Jupiter-like planet orbiting one of the smallest stars known.
The National Aeronautics and Space Administration said the technique, called astrometry, involves measuring the motions of a star as an unseen planet tugs the star back and forth. However, the method had failed to identify any exoplanets.
But now two astronomers from NASA's Jet Propulsion Laboratory using the technique have identified a new exoplanet around one of 30 stars they studied. It's the first exoplanet to be discovered using astrometry.
"We found a Jupiter-like planet at around the same relative place as our Jupiter, only around a much smaller star," NASA astronomer Steven Pravdo, lead author of the study, said. "It's possible this star also has inner rocky planets. And since more than seven out of 10 stars are small like this one, this could mean planets are more common than we thought."
The newly found exoplanet is about 20 light-years from Earth in the constellation Aquila.
"This is an exciting discovery because it shows that planets can be found around extremely light-weight stars," Wesley Traub, chief scientist for NASA's Exoplanet Exploration Program, said. "This is a hint that nature likes to form planets, even around stars very different from the sun."
The research is to appear in the Astrophysical Journal.
New cellular target for HIV drugs proposed
GAINESVILLE, Fla., May 28 (UPI) -- U.S. scientists say human immunodeficiency virus drug developers should focus on immune cells called macrophages instead of traditionally targeted T cells.
In the largest study of its kind, researchers from the University of Florida and five other institutions said they discovered that in diseased cells, such as cancer cells, that are also infected with HIV, nearly all the virus was packed into macrophages, whose job is to "eat" invading disease agents. The researchers said they also found that up to half of the macrophages were hybrids, formed when pieces of genetic material from several parent HIV viruses combined to form new strains.
Such "recombination," they said, is responsible for formation of mutants that easily elude immune system surveillance and escape from anti-HIV drugs.
"Macrophages are these little factories producing new hybrid particles of the virus, making the virus probably even more aggressive over time," Assistant Professor and study co-author Marco Salemi said. "If we want to eradicate HIV we need to find a way to actually target the virus specifically infecting the macrophages."
The findings were reported in a recent issue of the online journal PLoS One.
Agricultural fires impact arctic ice melt
DURHAM, N.H., May 28 (UPI) -- Researchers from the United States and around the world have determined springtime agricultural fires have a significant impact on the melting of arctic ice.
The scientists are to meet at the University of New Hampshire next week to discuss findings from the most ambitious effort ever undertaken to measure "short-lived" airborne pollutants in the Arctic Circle.
The two-year international project known as Polarcat focused on the transport of pollutants into the arctic from lower latitudes.
Among other findings, the researchers learned large-scale agricultural burning to remove crop residues or clear brush for grazing in Russia, Kazakhstan, China, the United States, Canada and Ukraine is having a much greater impact than previously thought because of the black carbon or soot the fires produce.
The scientists said soot, produced through incomplete combustion of biomass and fossil fuels, may account for 30 percent of arctic warming since soot warms the surrounding air and, when deposited on ice and snow, absorbs solar energy and adds to the melting process.
"Targeting such emissions offers a supplemental and parallel strategy to carbon dioxide reductions, with the advantage of a much faster temperature response, and the benefit of health risk reductions," researcher Ellen Baum said.
More information about Polarcat is available at www.polarcat.no.
Cancer cells need healthy genes to survive
BOSTON, May 28 (UPI) -- U.S. scientists say they've discovered cancer cells rely on normal, healthy genes as much as they rely on mutated genes to maintain their abnormal state.
Researchers at the Harvard Medical School and Brigham and Women's Hospital said they reduced the production of thousands of normal proteins to determine which were required for cancer cells to survive. They found cancer cells growing in a dish rely heavily on many normal proteins and when some of those protein levels drop, cancer cells die.
The researchers said their study also revealed some limitations of the Cancer Genome Atlas, a federally funded effort to sequence cancer genomes. If scientists focus exclusively on DNA sequences, they'll miss key aspects of cancer cell biology, including the reliance on normal proteins, the researchers said.
Professor Stephen Elledge said the findings might lead to a drug cocktail approach in treating tumors.
"We might be able to tinker with the levels of these proteins and cripple cancer cells without hurting normal cells in the body, though this needs to be tested in tumor models," he said.
The study that included researchers Ji Luo, Michael Emanuele, Danan Li, Chad Creighton, Michael Schlabach, Thomas Westbrook and Kwok-Kin Wong appears in the journal Cell.
