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coastline in the U.S. State of California sampled by the state water board harbored fish with mercury in such high concentrations that they shouldn't be eaten by young women and children, a newly released survey has found.Fourteen percent of locations had similarly elevated levels of PCBs, according to the survey published by The Los Angeles Times on Sunday.The most elevated concentrations of mercury and PCBs were found in San Francisco Bay and San Diego Bay, said the survey funded by the state water board.The findings, part of a two-year inquiry that is the largest statewide survey of contaminants in sport fish along the California coast, examined more than 2,000 fish from three dozen species gathered in 2009 from waters near Los Angeles, San Francisco and San Diego, the paper said.The survey highlights the health problem of lingering mercury, a poisonous metal that is found in fish globally, and of PCBs, toxic chemicals the United States banned in the 1970s, the report said.Both substances continue to pose a risk to people who eat fish caught along the California coast because they can lead to nervous system damage and developmental problems in children and can cause cancer, liver damage and reproductive harm, the report quoted researchers as saying."Unfortunately, we're not seeing many areas that are totally clean," said Jay Davis, a senior scientist for the San Francisco Estuary Institute and lead author of the study. But a catalog of where and in what fish the substances abound should help anglers make better choices, Davis said. "With good information, people can reduce their exposure significantly."Sharks had some of the highest levels of mercury because of their unusual tendency to accumulate contaminants in their flesh, while chub mackerel had the lowest levels of contamination, according to the survey.The survey results were used in part to help craft new fish consumption guidelines issued earlier this week for anglers in San Francisco Bay, the first update there by state health officials in 17 years. The advisory identifies shiner perch and other surf perches as unsafe to eat in any quantity and warns young women and children not to eat white sturgeon, striped bass and sharks caught in the bay, The Times said.The buildup of metals and other chemicals in fish is such a problem along the Southern California coast that health officials two years ago expanded the number of fish species on the "do not eat" list from one to five because of high levels of PCBs, mercury and the banned pesticide DDT, the report noted.

BEIJING, Aug. 22 (Xinhuanet) -- Researchers have discovered how a human egg captures an incoming sperm for fertilization, paving the way to help couples suffering from infertility, according to media reports on Monday.An international team of researchers found that a sugar chain known as the sialyl-lewis-x sequence (SLeX) makes the outer coat of the egg “sticky,” which has proven to be helpful in binding the egg and the sperm.As a result, this observation has filled in a huge gap in the understanding of fertility and provides hope for ultimately helping couples who currently cannot conceive.Scientists and doctors know that a sperm identifies an egg when proteins on the head of the sperm match and bind to a series of specific sugars in the egg’s outer coating. With a successful match of proteins, the outside surfaces of the sperm and egg then bind together before merging, which is then followed by delivery of sperm’s DNA into egg.To identify this molecules, the researchers used ultra-sensitive mass-spectrometric imaging technology to observe and identify which molecules are most likely to be key in the binding process.They experimented with a range of synthesised sugars in the laboratory and found that it is SLeX that specifically binds sperm to an egg.According to the World Health Organisation, infertility affects about 15 percent of reproductive-aged couples around the world and almost one in every seven couples in Britain has problems conceiving a child for various reasons.

LOS ANGELES, June 23 (Xinhua) -- The sun and its inner planets may have formed differently than previously thought, NASA's Jet Propulsion Laboratory (JPL) said on Thursday.Data revealed differences between the sun and planets in oxygen and nitrogen, which are two of the most abundant elements in our solar system, said JPL in Pasadena, Los Angeles.Although the difference is slight, the implications could help determine how our solar system evolved, JPL said.NASA researchers drew the conclusion after analyzing samples returned by NASA's 2004 Genesis mission, according to JPL.The air on Earth contains three different kinds of oxygen atoms which are differentiated by the number of neutrons they contain. Nearly 100 percent of oxygen atoms in the solar system are composed of O-16, but there are also tiny amounts of more exotic oxygen isotopes called O-17 and O-18. Researchers studying the oxygen of Genesis samples found that the percentage of O-16 in the sun is slightly higher than on Earth or on other terrestrial planets. The other isotopes' percentages were slightly lower."We found that Earth, the moon, as well as Martian and other meteorites which are samples of asteroids, have a lower concentration of the O-16 than does the sun," said Kevin McKeegan, a Genesis co-investigator from University of California, Los Angeles (UCLA) and the lead author of one of two papers published this week in Science journal. "The implication is that we did not form out of the same solar nebula materials that created the sun -- just how and why remains to be discovered." Another paper detailed differences between the sun and planets in the element nitrogen. Like oxygen, nitrogen has one isotope, N- 14, that makes up nearly 100 percent of the atoms in the solar system, but there is also a tiny amount of N-15. Researchers studying the same samples saw that when compared to Earth's atmosphere, nitrogen in the sun and Jupiter has slightly more N-14, but 40 percent less N-15. Both the sun and Jupiter appear to have the same nitrogen composition. As is the case for oxygen, Earth and the rest of the inner solar system are very different in nitrogen."These findings show that all solar system objects including the terrestrial planets, meteorites and comets are anomalous compared to the initial composition of the nebula from which the solar system formed," said Bernard Marty, a Genesis co- investigator from Petrographic and Geochemical Research Center in Fracne and the lead author of the other new Science paper. " Understanding the cause of such a heterogeneity will impact our view on the formation of the solar system."Data were obtained from analysis of samples Genesis collected from the solar wind, or material ejected from the outer portion of the sun. This material can be thought of as a fossil of our nebula because the preponderance of scientific evidence suggests that the outer layer of our sun has not changed measurably for billions of years."The sun houses more than 99 percent of the material currently in our solar system, so it's a good idea to get to know it better, " said Genesis Principal Investigator Don Burnett of the California Institute of Technology, Pasadena, California. "While it was more challenging than expected, we have answered some important questions, and like all successful missions, generated plenty more."Genesis was launched in August 2000. The spacecraft traveled to Earth's L1 Lagrange Point about one million miles from Earth, where it remained for 886 days between 2001 and 2004, passively collecting solar-wind samples.JPL managed the Genesis mission for NASA's Science Mission Directorate, Washington. The Genesis mission was part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Alasca.

SYDNEY, Aug. 2 (Xinhua) -- Australia's general practitioners ( GPs) will not back the idea of routine prostate cancer tests for men as young as 40 despite growing calls for regular screening, the nation's largest professional general practice organization said on Tuesday.Spokesman for the Royal Australian College of General Practitioners (RACGP), Professor Chris Del Mar said there was not enough solid evidence to suggest major benefits from routine screening and that current tests were unable to detect "nasty" and potentially deadly forms of prostate cancer from ones that will not cause any harm."The problem is you end up treating lots of people who don't need to be treated," Del Mar said, adding that treatment could leave men impotent and with incontinence problems."You will treat 20 times as many people than would have ever been bothered by it. We don't yet know that treating prostate cancer is better than not treating it. We are not sure it does any good and could be doing more harm," he said.On the other hand, Australia's urologists and pathologists both want men aged 40 and over who are worried about developing the disease to be offered tests.The Royal College of Pathologists (RCPA) on Tuesday released an official recommendation on routine screening for men aged 40 and over if they were concerned about prostate cancer.The pathologists argue that blood tests for prostate cancer in men under 50 can predict their future risk of developing the disease by measuring their prostate specific antigen levels (PSA).They say that men with high PSA levels for their age should be tested annually, while those PSA levels are below the average could be tested less frequently.Their call for more routine testing contrasts with recommendations for GPs, whose `Red Book' medical guide does not support regular screening.Instead, it suggests GPs should inform men aged 50-70 of the risks and benefits of screening and only test if the patient requests one.RACGP spokesman Del Mar, who co-wrote the RACGP's recommendations, said while the Red Book was being revised "we are not going to liberalize it".Prostate cancer is one of the most common forms of cancer in Australia.About 20,000 cases of prostate cancer are diagnosed each year, with 3,300 men dying.Given the debate around prostate cancer tests, the Royal College of Pathologists wants to work with GPs, urologists and other medical organizations to develop a consensus on how and when to test for the disease, in a similar way to how experts approach breast cancer."It would be a good outcome for prostate cancer if we worked towards developing more of an umbrella document which reflected consensus among different stakeholder organizations. ," RCPA President Paul McKenzie said.

WASHINGTON, July 8 (Xinhua) -- U.S. President Barack Obama on Friday hailed space shuttle Atlantis' final flight in NASA's shuttle program, saying Americans across the country watched with pride as America reached for the heavens once more.Obama expressed his "sincere gratitude" to Atlantis astronauts and space workers because they "helped our country lead the space age.""Today's launch may mark the final flight of the space shuttle, " Obama said in a statement. "But it propels us into the next era of our never-ending adventure to push the very frontiers of exploration and discovery in space."Friday's flight is the 33rd voyage for Atlantis. Its return to the earth later this month will mark the end of the 30-year shuttle program."What a truly awesome day today," said NASA Associate Administrator for Space Operations Bill Gerstenmaier at the STS- 135 postlaunch news conference. "What you saw is the finest launch team and shuttle preparation teams in the world.""It truly was an awesome, spectacular launch," added Kennedy Space Center Director Bob Cabana, who looked ahead to plans for future development beyond the shuttle program as space station operations continue.Atlantis will be the last shuttle to be retired. Discovery was first in March, followed by Endeavour at the beginning of June. Each shuttle will head to a museum.When the U.S. space shuttle program officially ends later this year, the Russian space program's Soyuz capsule will be the only method for transporting astronauts to and from the station.