喀什为什么我的月经量很少(喀什治性功能障碍专科医院) (今日更新中)

BEIJING, Aug. 3 (Xinhuanet) -- The first man in Britain who received a complete plastic heart is allowed to leave hospital and live a relatively normal life at home.Matthew Green, 40, who was dying from arrhythmogenic right ventricular cardiomyopathy, was awaiting a transplant when his condition became so bad that the doctors at Papworth Hospital, the world renowned heart center near Cambridge, decided to give him Britain’s first ever full artificial heart.During a six-hour operation on June 9, 2011, surgeons replaced Mr Green's damaged heart with the device which will serve the role of muscles and ventricles.Unlike previous artificial hearts, they have usually only replaced parts of the organ, the new one is powered by a pump which sits outside the body and can be held in a backpack or shoulder bag.All Mr Green has to do is replace the batteries in the pump every few hours and the heart should last up to three years.Transplant milestones1964 US National Institutes of Health starts artificial heart programme.1966 First transplant of partial mechanical heart, to assist pumping of ventricle.1969 Texas man receives first total artificial heart transplant. After 64 hours on the mechanical device received a donor organ, but died within two days.1982 Artificial heart designed by Utah University doctor Robert Jarvik implanted into man who survived for 112 days.2001 First surgical implant of internally powered artificial heart, which was charged via transduction through skin.

WASHINGTON, June 6 (Xinhua) -- Women who have higher levels of the appetite-controlling hormone leptin have fewer symptoms of depression, and this apparent inverse relationship is not related to body mass index (BMI), a new study finds. The results were presented Monday at The Endocrine Society's 93rd Annual Meeting in Boston, the United States."Animal data suggest that leptin may reduce anxiety and improve depression. Our study in women suggests that leptin may indeed have antidepressant qualities," said the study's lead author, Elizabeth Lawson, of Massachusetts General Hospital and Harvard Medical School in Boston.Leptin, the product of fat cells, signals satiety, or fullness. It is low in thin women and high in obese women, according to Lawson. She also said there is an increased prevalence of anxiety and depression in certain conditions in which leptin levels are typically low. These include the eating disorder anorexia nervosa, in which there is abnormally low weight and body fat, and functional hypothalamic amenorrhea, in which women have stopped menstruating despite having normal weight."It is unknown whether low leptin levels contribute to the development of mood disorders in these women," Lawson said.She and her co-workers studied the relationship between leptin levels and symptoms of anxiety and depression in 64 women. Fifteen of the women had anorexia nervosa, 12 were normal weight with hypothalamic amenorrhea, 20 were normal weight and in good health, and 17 were overweight or obese but still healthy.All subjects were asked questions to assess symptoms of depression and anxiety, with high scores indicating more symptoms. Besides measuring leptin levels in the blood, the researchers assessed the women's BMI, a measure of weight for height.The relationship between leptin and depression symptoms was independent of BMI. This finding indicates that leptin may mediate symptoms of depression and that this effect is not a function of low weight, Lawson said."Further research administering leptin to humans will be important in understanding whether this hormone has a potential role in the treatment of depression," she said.

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.

WASHINGTON, May 30 (Xinhua) -- After nearly 12 days together in orbit, U.S. space shuttle Endeavour undocked from the International Space Station on Sunday night, NASA announced on Monday.According to NASA, the undocking took place at 11:55 p.m. EDT ( 0355 GMT Monday) as the spacecraft sailed 215 miles (346 km) above Bolivia.Pilot Greg Johnson, at the aft flight deck controls, flew Endeavour in a circle around the station at distances of about 450 to 650 feet. Crew members took still and video images of the station.The Space Shuttle Endeavour is seen as it departs the International Space Station after undocking in this image from NASA TV May 29, 2011.As Johnson was about to begin the flyaround, Commander Mark Kelly radioed mission control that he could see the two-billion-U. S.-dollar Alpha Magnetic Spectrometer (AMS) particle physics detector Endeavour had brought to orbit. "It's a new day for science on the space station," he said to mission control.The AMS will be left at the space station to scour the universe for clues about dark matter and antimatter. Endeavour is scheduled to land at the Kennedy Space Center at 2:35 a.m. (0635 GMT) on Wednesday.During their stay at the space station, the Endeavour crew conducted four spacewalks to complete construction of the U.S. side of the 100-billion-dollar outpost, a project of 16 nations that has been being assembled in orbit since 1998.They also brought up a logistics carrier with spare parts and performed some maintenance and installation work during the four spacewalks, the last to be carried out by an American shuttle crew.NASA plans to decommission Endeavour, its youngest shuttle with 25 voyages, and send it to a museum in Los Angeles for display.NASA's 30-year-old shuttle program is ending due to high operating costs. The Obama administration wants to spur private companies to get into the space taxi business, freeing NASA to focus on deep space exploration and new technology development.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 space station.

BEIJING, July 26 (Xinhuanet) -- Hong Kong scientists announced that they had determined the idea of time travel is impossible by proving nothing can travel faster than the speed of light.The finding is contained in a study done by a research team from Hong Kong University of Science and Technology. The study was published Monday in a scientific journal "Physical Review Letters" in the United States."The study, which showed that single photons also obey the speed limit c, confirms Einstein's causality, that is, an effect cannot occur before its cause," the university said on its website."By showing that single photons cannot travel faster than the speed of light, our results bring a closure to the debate on the true speed of information carried by a single photon." said Professor Du Shengwang, who led the study.The possibility of time travel was raised 10 years ago when scientists discovered the optical pulses in some specific medium might propagate information in a faster-than-light speed."Our findings will also likely have potential applications by giving scientists a better picture on the transmission of quantum information." Du said.

来源：资阳报