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Cassini completes first Enceladus flyby

PASADENA, Calif., Aug. 12 (UPI) -- The U.S. space agency says its Cassini spacecraft is sending data to Earth following its 30-mile flyby of Saturn's moon Enceladus.

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Shorty after 9 p.m. Monday Cassini's signal was picked up by the National Aeronautics and Space Administration's Deep Space Network station in Canberra, Australia, and relayed to Cassini mission control at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

NASA scientists said the closest approach occurred at approximately 3:20 p.m., while Cassini was traveling at 40,000 miles per hour relative to Enceladus.

During the flyby, Cassini focused its cameras and other remote sensing instruments on Enceladus with an emphasis on the moon's south pole, where parallel fissures dubbed "tiger stripes" line the region. NASA said that area is of particular scientific interest because geysers of water-ice and vapor continuously jet from the fissures and supply material to Saturn's E-ring.

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Scientists hope to learn more about the fissures and whether liquid water is indeed the engine powering the geysers.

Two more Enceladus flybys are planned for October.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.


New chemo shows promise in lung cancer

OSAKA, Japan, Aug. 12 (UPI) -- A Japanese-led study suggests an experimental combination of chemotherapy agents might be a good alternative to standard lung cancer treatment.

In the phase II multicenter study of 56 patients with advanced small cell lung cancer, scientists said response rate, progression-free survival and overall survival from a combination of S-1 and irinotecan were similar to, or better than, those reported from standard treatment with platinum-based chemotherapy regimens.

"There continues to be reluctance on the part of both patients and treating physicians to accept the toxicity of platinum-based therapy, given the associated small gain in survival, so active therapies with improved toxicity profiles are clearly needed," said the study's lead investigator, Dr. Isamu Okamoto, an associate professor at Kinki University School of Medicine in Osaka, Japan.

Irinotecan, an intravenous drug used to treat colon cancer, was developed in Japan and approved for use in the United States in 1994.

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S-1 is approved for treating gastric cancer in Japan and Korea but is still in clinical trials in other areas, including the United States and Europe.

The study is reported in the Aug. 15 issue of the journal Clinical Cancer Research.


Old elephants may help young ones survive

NEW YORK, Aug. 12 (UPI) -- A U.S.-led study suggests memories of past droughts held by older female elephants might help herds survive modern climate change.

A recent study by the Wildlife Conservation Society and the Zoological Society of London provides evidence that experienced elephant matriarchs seem to give their family groups an edge in the struggle for survival during periods of famine and drought.

"Understanding how elephants and other animal populations react to droughts will be a central component of wildlife management and conservation," said Wildlife Conservation Society researcher Charles Foley, lead author of the study. "Our findings seem to support the hypothesis that older females with knowledge of distant resources become crucial to the survival of herds during periods of extreme climatic events."

The study's co-author, Nathalie Pettorelli of the ZSL, added: "Climate change is expected to lead to a higher occurrence of severe drought in Africa and our study suggests that such extreme climatic events may act as a selection force on animal populations. As animals battle to cope certain individuals, such as these grand dames of the elephant kingdom, might become increasingly important."

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The research is reported in a recent issue of the Royal Society's journal Biology Letters.


Dopamine pathways said to control conduct

EVANSTON, Ill., Aug. 12 (UPI) -- U.S. scientists say they've found some human behavior is controlled by balanced activation of two pathways in the brain using the neurotransmitter dopamine.

Professor James Surmeier and colleagues at Northwestern University say their discovery helps explain Parkinson's disease and drug addiction.

Dopamine "shapes the two main circuits of the brain that control how we choose to act …," said Surmeier, adding both circuits are in the brain's striatum, a region critical for translating thoughts into action. One circuit activates conduct while the other inhibits it.

In drug addiction, Surmeier explained that "dopamine released by drugs leads to abnormal strengthening of the cortical synapses driving the striatal 'go' circuits, while weakening synapses at opposing 'stop' circuits." The result is the compulsive conduct seen in addiction.

In a second experiment, the researchers created an animal model of Parkinson's disease by killing dopamine neurons. When the researchers simulated cortical commands to move, the inhibitory pathway was strengthened and the activation pathway was weakened.

"The study illuminates why Parkinson's patients have trouble performing everyday tasks like reaching across a table to pick up a glass of water when they are thirsty," Surmeier said.

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The research is reported in the journal Science.

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