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WASHINGTON, Nov. 16 (Xinhua) -- Data from NASA's Galileo spacecraft have provided scientists evidence of what appears to be a body of liquid water, equal in volume to the North American Great Lakes, beneath the icy surface of Jupiter's moon, Europa, the U.S. space agency announced Wednesday.The data suggest there is significant exchange between Europa's icy shell and the ocean beneath. This information could bolster arguments that Europa's global subsurface ocean represents a potential habitat for life elsewhere in our solar system. The findings will be published Thursday in the scientific journal Nature.Europa, which is slightly smaller than Earth's moon, is believed to have a large ocean of salty water deep beneath its frozen crust. Galileo spacecraft, launched by the space shuttle Atlantis in 1989, studied Jupiter, which is the most massive planet in the solar system, and some of its many moons.Pictures of it sent back by Galileo point to a tortured surface of cracks and jumbled ice. Seeking to understand how such weird topography evolved in a place with such dim sunlight, scientists believe that the answer lies in similar processes on Earth.Their model suggests that Europa's ice shell is about 10 kilometers thick and within it are giant pockets of water, lying at depths as shallow as three kilometers. Warm water from these sub-surface lakes wells up in plumes, causing the ice to become brittle, crack and then collapse. The ice turnover would be a plus for the prospects for life, as it would transfer energy and nutrients between the sub-glacial lake and the surface."One opinion in the scientific community has been if the ice shell is thick, that's bad for biology. That might mean the surface isn't communicating with the underlying ocean," said Britney Schmidt, lead author of the paper and postdoctoral fellow at the Institute for Geophysics, University of Texas at Austin. " Now, we see evidence that it's a thick ice shell that can mix vigorously and new evidence for giant shallow lakes. That could make Europa and its ocean more habitable.""The data opens up some compelling possibilities," said Mary Voytek, director of NASA's Astrobiology Program. "However, scientists worldwide will want to take a close look at this analysis and review the data before we can fully appreciate the implication of these results."

BEIJING, Oct. 11 (Xinhuanet) -- Debates in the medical field developed on Monday as a U.S. government panel recommended that men of all ages should stop getting prostate cancer blood screenings.The United States Preventive Services examined all the evidence and found little if any reduction in deaths from routine P.S.A. screening and suggested that the test does more harm than good to healthy men.The P.S.A. test for prostate cancer, a blood test to screen for a protein that may indicate cancer, has become widely used because it can help detect tiny tumors at a very early sta ge, when they are theoretically most treatable.Unfortunately, according to the task force, the vast majority of the results are false-positives: the men don’t actually have cancer. And most of those found to have cancerous cells would not suffer ill effects because their cancer is so slow-growing that it would not cut short their lives. Those with faster-growing cancers may also not be helped if the cancer is extremely aggressive.After the recommendation came out last week, many prostate cancer specialists have been pushing back.Urologist Dr. Mark DeGuenther said this recommendation is more about saving money than saving lives. He said death rates from prostate cancer have dropped 40 percent since men began getting screened at age 40 and he says it will save taxpayers and patients more money in the long run to diagnose and treat cancers earlier rather than wait and have to provide expensive care for advanced stage cancers."We all agree that we've got to do a better job of figuring out who would benefit from P.S.A. screening," said Dr. Scott Eggener, a prostate cancer specialist at the University of Chicago. "But a blanket statement of just doing away with it altogether ... seems over-aggressive and irresponsible."Dr. Deepak Kapoor, chairman and chief executive of Integrated Medical Professionals, which includes the nation's largest urology practice, said "We will not allow patients to die, which is what will happen if this recommendation is accepted."That task force's recommendation isn't final - it's a draft open for public debate. And obviously the debate is already under way.

BEIJING, Oct. 12 (Xinhuanet) -- Study found that women who took multivitamins may actually be at risk, media reports on Wednsday.Women who took the dietary supplements vitamin B6, folic acid, magnesium, zinc, copper, iron and multivitamins had a higher risk of death than women who did not.The new study, published in the Archives of Internal Medicine, examined more than 38,000 women aged 55 and older who took part in the Iowa Women's Health Study, which started in the mid 1980s. Researchers found the vitamins did nothing to reduce the risk of death and that most supplements have no positive effect on women's health.The study did not distinguish if the women in the study took the vitamins to fight diseases or to maintain health.Vitamin experts say the best way to make sure you are getting all necessary vitamins is to eat a well-balanced diet. The vitamins people take do not  depend on personal preference.

BEIJING, Sept. 30 (Xinhuanet) -- Tobacco companies concealed the knowledge of radioactive substance in cigarettes from public for over four decades, a new study revealed.The revelation was made by a research team from the University of California, Los Angeles, published on Thursday in the online edition of the U.S. medical journal Nicotine and Tobacco Research.The researchers analyzed 27 timeworn documents and discovered that tobacco companies had knew the existence of polonium-210, a hazardous radioactive substance, in the tobacco since 1959.The companies studied polonium-210 throughout the 1960s, and concealed their findings about the carcinogenic potential of the radioactive substance.Hrayr Karagueuzian, the study's lead author, said the tobacco companies' deception surprised him.According to the revelation, the companies had knew the "cancerous growths" in the lungs of smokers, and even calculated how much radiation a regular smoker would inhale over 20 years.Karagueuzian and his team conducted again the study recorded in the tobacco documents and found that the radiation in cigarettes would cause up to 138 deaths for every 1,000 smokers over a period of 25 years.However, tobacco manufacturer denied that they had concealed the facts from the public.David Sutton, spokesman of Philip Morris, the largest U.S. tobacco company, said the polonium-210 was a "naturally occurring element in the air" and had been widely discussed by the public health community for years.

WASHINGTON, Oct. 13 (Xinhua) -- In a trial that included about 35,000 men, those who were randomized to receive daily supplementation with vitamin E had a significantly increased risk of prostate cancer, according to a study published this week in the Journal of the American Medical Association.The study followed more than 35,533 men 50 or older at 427 sites in the United States, Canada and Puerto Rico. The men were divided into four groups who took daily doses of 400 international units of Vitamin E and 200 micrograms of selenium; Vitamin E and a placebo that looked like selenium; selenium and a placebo that looked like Vitamin E; or two placebos. The recommended daily intake of Vitamin E is about 22.4 international units.The researchers from the Cleveland Clinic found that the rate of prostate cancer detection was greater in all treatment groups when compared with placebo but was statistically significant only in the vitamin E alone group -- a 17 percent increased rate of prostate cancer detection. The difference in rates of prostate cancer between vitamin E and placebo became apparent during the participants' third year in the trial. The elevated risk estimate for vitamin E was consistent across both low- and high-grade disease."The observed 17 percent increase in prostate cancer incidence demonstrates the potential for seemingly innocuous yet biologically active substances such as vitamins to cause harm. The lack of benefit from dietary supplementation with vitamin E or other agents with respect to preventing common health conditions and cancers or improving overall survival, and their potential harm, underscore the need for consumers to be skeptical of health claims for unregulated over-the-counter products in the absence of strong evidence of benefit demonstrated in clinical trials," the researchers said.

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