成都怎么手术治疗血管畸形(成都治疗下肢静脉曲张价钱) (今日更新中)

WASHINGTON, Aug. 2 (Xinhua) -- The weakness of aging is associated with leaky calcium channels inside muscle cells and a drug already in Phase II clinical trials for the treatment of heart failure might plug those leaks, according to a report published Tuesday in the online edition of Cell Metabolism.Earlier studies by the research team led by Andrew Marks of Columbia University showed the same leaks underlie the weakness and fatigue that come with heart failure and Duchenne muscular dystrophy."It's interesting, normal people essentially acquire a form of muscular dystrophy with age," Marks said. "The basis for muscle weakness is the same." Extreme exercise like that done by marathon runners also springs the same sort of leaks, he added, but in that case damaged muscles return to normal after a few days of rest. A microscopic view shows smooth muscle cells derived from human embryonic stem cells showing the nuclei (blue) and proteins of the cytoskeleton (green) in this handout photo released to Reuters by the California Institute for Regenerative Medicine, March 9, 2009The leaks occur in a calcium release channel called ryanodine receptor 1 (RyR1) that is required for muscles to contract. Under conditions of stress, those channels are chemically modified and lose a stabilizing subunit known as calstabin1.Calcium inside of muscle cells is usually kept contained. When it is allowed to leak out into the cell that calcium itself is toxic, turning on an enzyme that chews up muscle cells. Once the leak starts, it's a vicious cycle. The calcium leak raises levels of damaging reactive oxygen species, which oxidize RyR1 and worsen the leak.The researchers made their discovery by studying the skeletal muscles of young and old mice. They also showed that 6-month-old mice carrying a mutation that made their RyR1 channels leaky showed the same muscular defects and weakness characteristic of older mice.When older mice were treated with a drug known as S107, the calcium leak in their muscles slowed and the animals voluntarily showed about a 50 percent increase in the amount of time spent wheel running. Now in clinical trials for patients with heart failure, the drug is known to work by restoring the connection between costabilin and RyR1.Despite considerable effort to understand and reverse age- related muscle wasting, there are no established treatments available. The new work suggests there may be hope in approaching the problem from a different angle."Most research has focused on making more muscle mass," Marks said. "What's different here is that we are focused not on muscle mass but on muscle function. More muscle doesn't help if it is not functional."

LOS ANGELES, July 18 (Xinhua) -- The spacecraft Dawn of the National Aeronautics and Space Administration (NASA) has returned the first close-up image of the giant asteroid Vesta after entering its orbit for the first time last week, the Jet Propulsion Laboratory (JPL) announced on Monday.The image taken for navigation purposes shows Vesta in greater detail than ever before, said JPL in Pasadena, California.On July 15, Dawn became the first probe to enter orbit around an object in the main asteroid belt between Mars and Jupiter.When Vesta captured Dawn into its orbit, there were approximately 9,900 miles (about 16,000 kilometers) between the spacecraft and the asteroid.Vesta is 330 miles (about 530 kilometers) in diameter and the second most massive object in the asteroid belt.NASA's Dawn spacecraft obtained this image with its framing camera on July 17, 2011. It was taken from a distance of about 9,500 miles (15,000 kilometers) away from the protoplanet Vesta. Each pixel in the image corresponds to roughly 0.88 miles (1.4 kilometers). Ground- and space-based telescopes have obtained images of Vesta for about two centuries, but they have not been able to see much detail on its surface."We are beginning the study of arguably the oldest extant primordial surface in the solar system," said Dawn principal investigator Christopher Russell from the University of California, Los Angeles, which is responsible for Dawn's mission science. " This region of space has been ignored for far too long. So far, the images received to date reveal a complex surface that seems to have preserved some of the earliest events in Vesta's history, as well as logging the onslaught that Vesta has suffered in the intervening eons."Vesta is thought to be the source of a large number of meteorites that fall to Earth. Vesta and its new NASA neighbor, Dawn, are currently approximately 117 million miles (about 188 million kilometers) away from Earth. The Dawn team will begin gathering science data in August.Observations will provide unprecedented data to help scientists understand the earliest chapter of the solar system and pave the way for future human space missions, according to JPL."Dawn slipped gently into orbit with the same grace it has displayed during its years of ion thrusting through interplanetary space," said Marc Rayman, Dawn chief engineer and mission manager at NASA's JPL. "It is fantastically exciting that we will begin providing humankind its first detailed views of one of the last unexplored worlds in the inner solar system."Although orbit capture is complete, the approach phase will continue for about three weeks. During approach, the Dawn team will continue a search for possible moons around the asteroid; obtain more images for navigation; observe Vesta's physical properties; and obtain calibration data.In addition, navigators will measure the strength of Vesta's gravitational tug on the spacecraft to compute the asteroid's mass with much greater accuracy than has been previously available, according to JPL.Dawn will spend one year orbiting Vesta, then travel to a second destination, the dwarf planet Ceres, arriving in February 2015. The mission to Vesta and Ceres is managed by JPL for the agency's Science Mission Directorate in Washington.Dawn is a project of the directorate's Discovery Program, which is managed by NASA's Marshall Space Flight Center in Huntsville, Alaska.

CHICAGO, Aug. 25 (Xinhua) -- Gold futures on the COMEX Division of the New York Mercantile Exchange on Thursday bounced off the biggest drop since March 2008, as the weakness in stock market enhanced appeal of gold as a safe-have investment.The most active gold contract for Dec. delivery gained 5.9 U.S. dollars, or 0.3 percent, to 1,763.2 dollars per ounce. The metal suffered on Wednesday the biggest one-day drop since March 19, 2008.Market analysts said that gold extended losses in earlier trading, hit by a margin-requirement increase, but the drop in global stock market gave a push to the metal. Both Dow Jones industrial average and S&P 500 declined on Thursday after a 3-day rise as a government report showed U.S. jobless claims rose last week.Besides, market hearsay went that Germany might be next to get a sovereign-debt downgrade, adding to the positive tone on gold market. German equity market also suffered sharp drop in the day.Many market watchers remained long-term bullish attitude toward gold although they said the precious metal could correct further in the short term. A trader noted that the fundamental factors driving uncertainty and fears are all still there.Expectations are growing that the Federal Reserve Chairman Ben Bernanke would not provide any form of stimulus in a speech scheduled for Friday at a yearly gathering of central bankers in Jackson Hole.Silver for Sept. delivery also rose 1.583 dollars, or four percent, to 40.745 dollars per ounce. Platinum for Oct. delivery lost 3.9 dollars, or 0.2 percent, to 1822.4 dollars per ounce.

SAN FRANCISCO, June 8 (Xinhua) -- Facebook Inc. will be probed by European Union (EU) regulators over its latest facial recognition feature rolling out worldwide, U.S. media reported on Wednesday.The feature, called Tag Suggestions, uses face recognition software to match users' new photos to other photos they are tagged in. It groups similar photos together and suggests the name of the friend in the photos.Facebook rolled out the feature in the United States late last year, where users can opt out of the feature by going to their private settings. But Facebook switched it on by default without telling users first when it became available on Tuesday in countries outside of the United States.A group of privacy watchdogs from 27 EU nations will study the measure for possible rule violations, a Luxembourg official of Article 29 Data Protection Working Party told Bloomberg. The Working Party, an independent EU advisory body on data protection and privacy, comprises the data protection regulators of all the 27 EU member states."Tags of people on pictures should only happen based on people' s prior consent and it can't be activated by default," said the Luxembourg official, Gerald Lommel. He noted that such automatic features "can bear a lot of risks for users" and the European data- protection regulators will "clarify to Facebook that this can't happen like this."Authorities in Britain and Ireland said they are also looking into the new function on Facebook. The British Information Commissioner's Office told Bloomberg that "the privacy issues that this new software might raise are obvious," saying it is "speaking to Facebook" about the issue.Facebook has been under scrutiny by EU regulators for several privacy concerns, such as users' default settings and how the company uses the information collected from its social network website.

BEIJING, Aug. 24 (Xinhuanet) -- Facebook said it is overhauling its privacy settings to give members easier, more precise control over who sees posts, photos and other content over the vast social network.Starting Thursday, Facebook is rolling out new privacy tools that are placed with each piece of content, replacing options that are now buried in overall account settings.Privacy has been a consistently sticky problem for the Palo Alto firm, which has felt the heat from privacy advocates and government regulators. And recently, Facebook faced stiffer competition from Google's new Google+ social network, which was hailed for including a "circles" feature with easy-to-use privacy settings.Instead of vague labels such as "everyone," which have been mistaken for a Facebook member's social network instead of anyone on the Internet, the new system will include more precise words such as "public.""You have told us that 'who can see this?' could be clearer across Facebook, so we have made changes to make this more visual and straightforward," Chris Cox, Facebook's vice president of product, said in blog post."The main change is moving most of your controls from a settings page to being inline, right next to the posts, photos and tags they affect. Plus there are several other updates here that will make it easier to understand who can see your stuff (or your friends') in any context," Cox said.While privacy advocates reserved judgment until the new settings are actually released, they were optimistic the changes will benefit consumers."These changes do make me feel very confident in the direction that Facebook is going and the way they are thinking about privacy," said Erica Newland, policy analyst for the Center for Democracy & Technology in Washington, D.C.

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