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LOS ANGELES, July 18 (Xinhua) -- At least 70 genetic mutations may be involved in the formation of colon cancer, far more than scientists previously thought, a new study suggests.The study by researchers at University of Texas (UT) Southwestern Medical Center contradicts previous thinking that only a few mutated genes may play a role in the development of colon cancer."The ways we've been treating patients up to now is to just go after one target when we should be going after three to four different pathways simultaneously," said Dr. Jerry W. Shay, vice chairman and professor of cell biology at UT Southwestern.The new study identified 65 candidate genes and at least five passenger genes whose mutations play significant roles in cancer development. Inactivating the function of any of these tumor- suppressing genes led to a key step in cancer development called anchorage-independent growth, meaning cells piled up on top of each other rather than aligning neatly.According to previous studies, there were 151 candidate genes and that mutations in just eight to 15 of them would lead to cancer. There were 700 other genes classified as passenger genes whose mutations were incidental to cancer growth.Current cancer treatments target just one or two known cancer- driver genes. While patients may get transient tumor burden reduction, almost universally tumor growth returns."Those numbers are dead wrong," Dr. Shay said, suggesting a new approach to colon cancer treatments targeting multiple genes and pathways simultaneously.The next step is further research to classify more accurately which genes drive cancer and which are merely passengers, the researchers said.Study findings were published in the July 2011 Cancer Research (Priority Reports).
LOS ANGELES, June 20 (Xinhua) -- NASA's Cassini spacecraft has successfully completed its second-closest encounter with Saturn's icy moon Helene, beaming down raw images of the small moon, the Jet Propulsion Laboratory (JPL) said on Monday.At closest approach on June 18 Cassini flew within 4,330 miles (6,968 kilometers) of Helene's surface, the second closest approach to Helene of the entire mission, said JPL in Pasadena, Los Angeles.This flyby will enable scientists to finish creating a global map of Helene, so they can better understand the history of impacts to the moon and gully-like features seen on previous flybys, according to JPL.Passing from Helene's night side to the moon's sunlit side, Cassini also captured images of the Saturn-facing side of the moon in sunlight, a region that was only illuminated by sunlight reflected off Saturn the last time Cassini closely encountered with the moon in March 2010.The closest Helene encounter of the mission took place on March 10, 2010, when Cassini flew within 1,131 miles (1,820 kilometers) of the moon.The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL, while the imaging team is based at the Space Science Institute in Boulder, Colorado.
WASHINGTON, Aug. 17 (Xinhua) -- Latest research shows that the Moon could be younger than previous estimates. The findings were published online Wednesday in the Nature journal.The prevailing theory of the Moon's origin is that it was created by a giant impact between a large planet-like object and the proto-Earth. The energy of this impact was sufficiently high that the Moon formed from melted material that was ejected into space. As the Moon cooled, this magma solidified into different mineral components. Analysis of lunar rock samples thought to have been derived from the original magma has given scientists a new estimate of the Moon's age.According to this theory for lunar formation, a rock type called ferroan anorthosite, or FAN, is the oldest of the Moon's crustal rocks, but scientists have had difficulty dating FAN samples. The research team used newly refined techniques to determine the age of a sample of FAN from the lunar rock that was brought back to Earth by the Apollo 16 mission in 1972.The team analyzed the isotopes of the elements lead and neodymium to place the FAN sample's age at 4.36 billion years. This figure is significantly younger than earlier estimates of the Moon's age that range as old as the age of the solar system at 4. 568 billion years. The new, younger age obtained for the oldest lunar crust is similar to ages obtained for the oldest terrestrial minerals -- zircons from western Australia -- suggesting that the oldest crusts on both Earth and Moon formed at approximately the same time, and that this time dates from shortly after the giant impact.This study is the first in which a single sample of FAN yielded consistent ages from multiple isotope dating techniques. This result strongly suggests that these ages pinpoint the time at which the sample crystallized."The extraordinarily young age of this lunar sample either means that the Moon solidified significantly later than previous estimates, or that we need to change our entire understanding of the Moon's geochemical history," Carnegie Institute of Science's geochemist and study author Richard Carlson said.
PARIS, Aug. 19 (Xinhua) -- Marine scientists and representatives from the private sector and military establishments would meet at UNESCO at the end of this month to measure noise's impact on marine life, the Paris-based UN scientific branch UNESCO said Friday.The main agenda of the meeting, which is due from Aug. 30 to Sep. 1, was to discuss the program of the International Quiet Ocean Experiment (IQOE)."This decade-long project aims to fill the considerable knowledge gaps in this area, so that management of ocean noise can be more informed and effective," UNESCO said in a statement.The Quiet Ocean Experiments was initiated against the background that human activities on the high seas have increased significantly in recent decades, and resulted in impact upon many marine species relying mainly on sound to communicate.However, some sounds are suspected to alter the behavior of marine animals. For example, several whale species have raised the volume of the squeaks, clicks and moans by which they communicate with each other.The experiment is organized by the Scientific Committee on Oceanic Research (SCOR) and the Partnership for Observation of the Global Oceans (POGO), of which UNESCO's Intergovernmental Oceanographic Commission (IOC) is a member.
WASHINGTON, Aug. 31 (Xinhua) -- Astronomers using NASA's Chandra X-ray Observatory discovered the first pair of supermassive black holes in a spiral galaxy similar to the Milky Way, NASA announced Wednesday.Approximately 160 million light years from Earth, the pair is the nearest known such phenomenon.The black holes are located near the center of the spiral galaxy NGC 3393. Separated by only 490 light years, the black holes are likely the remnant of a merger of two galaxies of unequal mass a billion or more years ago.Both of the supermassive black holes are heavily obscured by dust and gas, which makes them difficult to observe in optical light. Because X-rays are more energetic, they can penetrate this obscuring material. Chandra's X-ray spectra show clear signatures of a pair of supermassive black holes."If this galaxy weren't so close, we'd have no chance of separating the two black holes the way we have," said Pepi Fabbiano of the Harvard-Smithsonian Center for Astrophysics, who led the study that appeared Wednesday in on-line issue of the journal Nature. "Since this galaxy was right under our noses by cosmic standards, it makes us wonder how many of these black hole pairs we've been missing."Previous observations in X-rays and at other wavelengths indicated that a single supermassive black hole existed in the center of NGC 3393. However, a long look by Chandra allowed the researchers to detect and separate the dual black holes. Both black holes are actively growing and emitting X-rays as gas falls towards them and becomes hotter.When two equal-sized spiral galaxies merge, astronomers think it should result in the formation of a black hole pair and a galaxy with a disrupted appearance and intense star formation. A well-known example is the pair of supermassive black holes in NGC 6240, which is located about 330 million light years from Earth.However, NGC 3393 is a well-organized spiral galaxy, and its central bulge is dominated by old stars. These are unusual properties for a galaxy containing a pair of black holes.