喀什精子质量检查费用多少(喀什怎样治疗三度宫颈糜烂) (今日更新中)

WASHINGTON, June 16 (Xinhua) -- Cells in the human body are constantly being exposed to stress from environmental chemicals or errors in routine cellular processes. While stress can cause damage, it can also provide the stimulus for undoing the damage. New research by a team of scientists at the University of Rochester has unveiled an important new mechanism that allows cells to recognize when they are under stress and prime the DNA repair machinery to respond to the threat of damage.Their findings will be published Friday in journal Science. Cells in the human body are constantly being exposed to stress from environmental chemicals or errors in routine cellular processes. While stress can cause damage, it can also provide the stimulus for undoing the damage.The scientists, led by biologists Vera Gorbunova and Andrei Seluanov, focused on the most dangerous type of DNA damage -- double strand breaks. Unrepaired, this type of damage can lead to premature aging and cancer. They studied how oxidative stress affects efficiency of DNA repair. Oxidative stress occurs when the body is unable to neutralize the highly-reactive molecules, which are typically produced during routine cellular activities.The research team found that human cells undergoing oxidative stress synthesized more of a protein called SIRT6. By increasing SIRT6 levels, cells were able to stimulate their ability to repair double strand breaks. When the cells were treated with a drug that inactivated SIRT6, DNA repair came to a halt, thus confirming the role of SIRT6 in DNA repair. Gorbunova notes that the SIRT6 protein is structurally related to another protein, SIR2, which has been shown to extend lifespan in multiple model organisms."SIRT6 also affects DNA repair when there is no oxidative stress," explains Gorbunova. "It's just that the effect is magnified when the cells are challenged with even small amounts of oxidative stress."SIRT6 allows the cells to be economical with their resources, priming the repair enzymes only when there is damage that needs to be repaired. Thus SIRT6 may be a master regulator that coordinates stress and DNA repair activities, according to Gorbunova.

BEIJING, Aug. 10 (Xinhuanet) -- A new technology can tell pregnant women whether they're having a boy or girl as early as seven weeks into a pregnancy -- months earlier than usual, according to media reports Wednesday.The technology works by detecting "cell-free fetal DNA," or DNA from the fetus, which floats freely in a pregnant woman's blood, said author Diana Bianchi of the Tufts University School of Medicine in Boston. Her analysis of 57 studies from peer-reviewed medical journals showed that these blood tests, common in Europe but not in the U.S. can reveal a fetus' sex only a week or two after a pregnant woman misses her period. Women usually learn the fetus' sex through an ultrasound at 18 to 20 weeks.The technology will help families worried by having a child with rare genetic disorders that typically affect only boys, such as hemophilia or a type of muscular dystrophy, said Joseph Biggio, director of the Trimester Genetics Screening Clinic at the University of Alabama-Birmingham.If they're having a girl, however, they can stop worrying, he added, and avoid further invasive tests, which can provide a definitive answer about genetic disorders, but also increase the risk of miscarriage. Women who learn they're carrying boys would still need a definitive test, such as an amniocentesis, to find out if their fetus is affected.

SINGAPORE, July 6 (Xinhua) -- A team of researchers in Singapore has designed a tube with special robotic hands that allows doctors to perform surgery on a patient's inner organs without resulting in scars, local media reported on Wednesday.The special "robotic hands" were fixed to the tube to access a patient's stomach. Compared with traditional methods which use only one robotic hand, the new device known as master and slave transluminal endoscopic robot, or MASTER, is more nimble, thereby allowing complex operations, the Lianhe Zaobao reported.Louis Phee, an associate professor at the Nanyang Technological University who led the team of researchers, had spent six years to develop the gadget, which cut an eight-hour procedure to just 17 minutes, said doctors at India's Asian Institute of Gastroenterology.The gadget, still in the trial stage, has been tested earlier this month on three patients at the Indian hospital. It is also expected to be tried out in Germany and China's Hong Kong later. The patients can leave the hospital much sooner than they would have using traditional gadgets.Phee said he expected the gadget to be available on the market as early as three years from now, after going through clinical trials and getting the approval from authorities.He also saw a potential for the gadget to be used on other organs by cutting a small spit on stomach that allows the gadget to go through to access the site.

WASHINGTON, June 23 (Xinhua) -- NASA's next Mars rover has completed the journey from its California birthplace to Florida in preparation for launch this fall, the U.S. space agency said Thursday in a statement.The Mars Science Laboratory (MSL) rover, also known as Curiosity, arrived Wednesday at NASA's Kennedy Space Center aboard an Air Force C-17 transport plane. It was accompanied by the rocket-powered descent stage that will fly the rover during the final moments before landing on Mars.The rover's aeroshell -- the protective covering for the trip to the Red Planet -- and the cruise stage, which will guide it to Mars, arrived at Kennedy last month. The mission is targeted to launch from Cape Canaveral Air Force Station between Nov. 25 and Dec. 18. The car-size rover will land on Mars in August 2012.The rover and other spacecraft components will undergo more testing before mission staff stack them and fuel the onboard propulsion systems. Curiosity should be enclosed in its aeroshell for the final time in September and delivered to Kennedy's Launch Complex 41 in early November for integration with a United Launch Alliance Atlas V rocket.Curiosity is about twice as long and more than five times as heavy as any previous Mars rover. Its 10 science instruments include two for ingesting and analyzing samples of powdered rock delivered by the rover's robotic arm. During a prime mission lasting one Martian year -- nearly two Earth years -- researchers will use the rover's tools to study whether the landing region has had environmental conditions favorable for supporting microbial life and favorable for preserving clues about whether life existed.

SAN FRANCISCO, July 7 (Xinhua) -- Apple announced Thursday that over 15 billion applications have been downloaded from its App Store by more than 200 million Apple mobile devices users worldwide."Thank you to all of our amazing developers who have filled it with over 425,000 of the coolest apps and to our over 200 million iOS users for surpassing 15 billion downloads," said Phillip Schiller, Apple's senior vice president of worldwide product marketing, in a statement.Launched on July 10, 2008, Apple's digital application distribution platform has been growing at a fast speed. It took nine months to hit one billion downloads and five billion in June 2010. In January, Apple gave a 10,000-U.S. dollar App Store gift card to a user who downloaded the 10 billionth application.In Thursday's statement, the Cupertino, California-based company said it had paid developers 2.5 billion dollars to date.Apple's mobile market place is far ahead of Google's Android Market. At its annual I/O conference in May, Google said there had been 4.5 billion app installs so far. But Google said the growth of its mobile operating system and applications is accelerating with its store hitting another billion downloads every 60 days.Currently, Apple is in a legal battle against Amazon over the use of "Appstore," which the online retailer launched in March to sell mobile applications to Google's Android platform users.On Wednesday, a federal judge denied Apple's request to immediately stop Amazon from using the term "Appstore."Meanwhile, Amazon, Microsoft, HTC, Nokia and Sony Ericsson have filed complaints against Apple in Europe, seeking to get Apple's trademarks for "App Store" and "Appstore" invalidated.

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