郑州郑大一附院做近视眼手术费用(郑州微创近视矫正手术) (今日更新中)

WASHINGTON, May 11 (Xinhua) -- Johns Hopkins University researchers have demonstrated that human liver cells derived from adult cells coaxed into an embryonic state can engraft and begin regenerating liver tissue in mice with chronic liver damage.The work, published Wednesday in the journal Science Translational Medicine, suggests that liver cells derived from so- called "induced-pluripotent stem cells (iPSCs)" could one day be used as an alternative to liver transplant in patients with serious liver diseases, bypassing long waiting lists for organs and concerns about immune system rejection of donated tissue."Our findings provide a foundation for producing functional liver cells for patients who suffer liver diseases and are in need of transplantation," says Yoon-Young Jang, assistant professor of oncology at the Johns Hopkins Kimmel Cancer Center. "iPSC-derived liver cells not only can be generated in large amounts, but also can be tailored to each patient, preventing immune-rejection problems associated with liver transplants from unmatched donors or embryonic stem cells." A microsopic view shows human embryonic stem cells in various stages of differentiation into liver cells in this photo taken at Stanford University and released by the California Institute for Regenerative Medicine, March 9, 2009iPSCs are made from adult cells that have been genetically reprogrammed to revert to an embryonic stem cell-like state, with the ability to transform into different cell types. Human iPSCs can be generated from various tissues, including skin, blood and liver cells.Although the liver can regenerate in the body, end-stage liver failure caused by diseases like cirrhosis and cancers eventually destroy the liver's regenerative ability, Jang says. Currently, the only option for those patients is to receive a liver organ or liver cell transplant, a supply problem given the severe shortage of donor liver tissue for transplantation. In addition, mature liver cells and adult liver stem cells are difficult to isolate or grow in the laboratory, she says. By contrast, iPSCs can be made from a tiny amount of many kinds of tissue; and the embryonic stem- like iPSCs can grow in laboratory cultures indefinitely.For the study, Jang and colleagues generated human iPSCs from a variety of adult human cells, including liver cells, fibroblasts ( connective tissue cells), bone marrow stem cells and skin cells. They found that though the iPSCs overall were molecularly similar to each other and to embryonic stem cells, they retained a distinct molecular "signature" inherited from the cell of origin.

BAIKONUR, Kazakhstan, April 5 (Xinhua) -- Russia launched a spacecraft with three astronauts on board from the Kazakh Baikonur space center early on Tuesday, Xinhua correspondents reported from the site.The Soyuz TMA-21 spacecraft atop a Soyuz-FG carrier rocket blasted off at 02:18 a.m. Moscow time (2218 GMT April 4), sending to the International Space Station (ISS) Russian cosmonauts Alexander Samokutyaev and Andrei Borisenko and U.S. astronaut Ronald Garn.The Russian Soyuz TMA-21 spacecraft, named after the first cosmonaut Yuri Gagarin, carrying the International Space Station (ISS) crew of U.S. astronaut Ronald Garan, Russian cosmonauts Alexandr Samokutyaev and Andrey Borisenko, blasts off at the Baikonur cosmodrome, April 5, 2011.The Soyuz TMA-21, named after the first cosmonaut Yuri Gagarin, was scheduled to dock with the ISS at 03:18 a.m. Moscow time (2318 GMT April 6) on Thursday.According to the Russian Federal Space Agency (Roscosmos), the three new crew members are expected to spend 170 days in the ISS. During the period, they will receive two U.S. space shuttles and three Russian Progress cargo ships, conduct a spacewalk and carry out over 40 experiments.The launch is dedicated to the 50th anniversary of the first flight into space in 1961 carried out by Gagarin.

UNITED NATIONS, April 7 (Xinhua) -- To celebrate the 50th anniversary of the first human space flight, accomplished on April 12, 1961 by Soviet cosmonaut Yuri Gagarin, the Russian Permanent Mission to the United Nations, the Russian Federal Space Agency and the ITAR-TASS information agency organized an exhibition which was opened here on Thursday."The first human space flight is not one of the most significant events of the past century, but of human history in general," Vitaly Churkin, the Russian permanent representative to the UN, said at the opening ceremony."It's a symbol of courage, thirst for knowledge, and progress," Churkin said.The exhibition contained archival photos telling the story of the first human space flight and of those who made it possible, and historic pictures of Gagarin.As part of the celebration of human space flight's 50th anniversary the UN Postal Administration designed postal stamps which will be issued on April 12, to tell the story of progress that humankind has made beyond earth's boundaries, as Kiyo Akasaka, Under-Secretary-General for Communications and Public Information put it."Fifty years have passed since that amazing voyage, but the legend of Gagarin's courage and journey to the 'final frontier' continues to be a source of inspiration for space exploration for peoples and nations around the world," Akasaka said at the opening of the exhibition.According to Akasaka, the exhibition "sparks people's imagination about what is possible through the peaceful use and exploration of outer space."Other attendees included Russian cosmonaut Oleg Kotov.Gagarin, also known as the Columbus of the Cosmos, traveled into outer space on the height of the Cold War when the Berlin Wall was built, at a moment when it was hardly impossible to imagine that more than 15 nations would work together in humanity' s permanent space outpost -- the International Space Station.The Russian icon of space spoke the historic words "the earth is blue, how wonderful. It is amazing."On Thursday the UN General Assembly adopted a resolution declaring April 12 as the International Day of Human Space Flight.

BEIJING, Jan. 26 (Xinhua) -- A senior Chinese official has called on the country's judicial officers and other law enforcers to maintain social justice and harmony by defusing and solving social contradictions.Zhou Yongkang, a member of the Standing Committee of the Political Bureau of the Communist Party of China (CPC) Central Committee, made the remark at a meeting to call on law enforcement officials to learn from Liu Yumei, who had served in grassroots judicial work for more than 20 years.During her service in a local community in southwest Chongqing Municipality, Liu Yumei had successfully reconciled more than 1,500 civil disputes and defused more than 10 possibly violent events. Liu died of illness from overwork in Jan. 2010 at only 46 years old.Zhou said law enforcement organs should regard preventing and reducing social disputes as an important job, and judicial officers should help people with their problems during their law-enforcement practices.

BEIJING, Feb. 8 (Xinhua) -- China's aviation authorities announced on Tuesday that more passengers traveled by air during the Spring Festival holidays, with Chinese airlines handling some 5.07 million passengers during the period.The number of passengers on flights during the Chinese Lunar New Year holidays, which ended Tuesday, was up 6 percent from the same period last year, according to the Civil Aviation Administration of China (CAAC).On average, 72 percent of the seats on flights across the country were loaded during the holiday travel season, up 2 percentage points from the same period last year, according to the CAAC.To prepare for the holiday travel surge, the CAAC arranged 38,992 flights during the holidays, including eight chartered flights to Egypt to fly home 1,796 Chinese travelers stranded amid massive protests in the African country.

来源：资阳报