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WASHINGTON, Aug. 4 (Xinhua) -- Researchers have found a way to turn mouse embryonic stem cells into sperm and this finding opens up new avenues for infertility research and treatment, according to a study published Thursday in the online edition of journal Cell,A Kyoto University team coaxed mouse embryonic stem cells into sperm precursors, called primordial germ cells (PGCs), and shown that these cells can give rise to healthy sperm. The researchers say that such in vitro reconstitution of germ cell development represents one of the most fundamental challenges in biology.When transplanted into mice that were unable to produce sperm normally, the stem cell derived PGCs produced normal-looking sperm, which were then used to successfully fertilize eggs. These fertilized eggs, when transplanted into a recipient mother, produced healthy offspring that grew into fertile male and female adult mice. The same procedure could produce fertile offspring from induced pluripotent stem cells that are often derived from adult skin cells."Continued investigations aimed at in vitro reconstitution of germ cell development, including the induction of female primordial germ cell-like cells and their descendants, will be crucial for a more comprehensive understanding of germ cell biology in general, as well as for the advancement of reproductive technology and medicine," the researchers wrote.

BEIJING, Sept. 1 (Xinhua) -- Chinese scientists have decided to reschedule the launch of the Tiangong-1, an unmanned space module, due to the failed launch of an experimental orbiter, a spokesperson with the project said Thursday.The decision to delay the launch was based on the consideration that the carrier rocket Long-March II-F, which would be used for the upcoming launch, belongs to the same series as the malfunctioning one that led to the experimental orbiter SJ-11-04 failing to enter Earth's orbit in August."As the investigation into the malfunction of the rocket Long-March II-C remains underway, it is not clear yet whether the malfunction is linked with the Long-March II-F," the unnamed spokesperson said.Previously, the Long-March II-F was expected to send the 8.5-metric ton Tiangong-1, or "Heavenly Palace 1," into space in the second half of this year to perform the nation's first space-docking procedure.The Tiangong-1 will dock with the unmanned Shenzhou-8 spacecraft, which will be sent into space after the Tiangong-1's launch."The specific launch date for the Tiangong-1 will be set based on the results of the investigation into the malfunctioning rocket," the spokesperson said, adding that the project's teams are currently double-checking every product that will be involved in the space-docking.The Shenzhou-8 spacecraft, the Long March II-F carrier rocket, and the Tiangong-1 have all been transferred to the Jiuquan Satellite Launch Center in northwest China's Gansu Province, the spokesperson said.

LOS ANGELES, June 23 (Xinhua) -- The sun and its inner planets may have formed differently than previously thought, NASA's Jet Propulsion Laboratory (JPL) said on Thursday.Data revealed differences between the sun and planets in oxygen and nitrogen, which are two of the most abundant elements in our solar system, said JPL in Pasadena, Los Angeles.Although the difference is slight, the implications could help determine how our solar system evolved, JPL said.NASA researchers drew the conclusion after analyzing samples returned by NASA's 2004 Genesis mission, according to JPL.The air on Earth contains three different kinds of oxygen atoms which are differentiated by the number of neutrons they contain. Nearly 100 percent of oxygen atoms in the solar system are composed of O-16, but there are also tiny amounts of more exotic oxygen isotopes called O-17 and O-18. Researchers studying the oxygen of Genesis samples found that the percentage of O-16 in the sun is slightly higher than on Earth or on other terrestrial planets. The other isotopes' percentages were slightly lower."We found that Earth, the moon, as well as Martian and other meteorites which are samples of asteroids, have a lower concentration of the O-16 than does the sun," said Kevin McKeegan, a Genesis co-investigator from University of California, Los Angeles (UCLA) and the lead author of one of two papers published this week in Science journal. "The implication is that we did not form out of the same solar nebula materials that created the sun -- just how and why remains to be discovered." Another paper detailed differences between the sun and planets in the element nitrogen. Like oxygen, nitrogen has one isotope, N- 14, that makes up nearly 100 percent of the atoms in the solar system, but there is also a tiny amount of N-15. Researchers studying the same samples saw that when compared to Earth's atmosphere, nitrogen in the sun and Jupiter has slightly more N-14, but 40 percent less N-15. Both the sun and Jupiter appear to have the same nitrogen composition. As is the case for oxygen, Earth and the rest of the inner solar system are very different in nitrogen."These findings show that all solar system objects including the terrestrial planets, meteorites and comets are anomalous compared to the initial composition of the nebula from which the solar system formed," said Bernard Marty, a Genesis co- investigator from Petrographic and Geochemical Research Center in Fracne and the lead author of the other new Science paper. " Understanding the cause of such a heterogeneity will impact our view on the formation of the solar system."Data were obtained from analysis of samples Genesis collected from the solar wind, or material ejected from the outer portion of the sun. This material can be thought of as a fossil of our nebula because the preponderance of scientific evidence suggests that the outer layer of our sun has not changed measurably for billions of years."The sun houses more than 99 percent of the material currently in our solar system, so it's a good idea to get to know it better, " said Genesis Principal Investigator Don Burnett of the California Institute of Technology, Pasadena, California. "While it was more challenging than expected, we have answered some important questions, and like all successful missions, generated plenty more."Genesis was launched in August 2000. The spacecraft traveled to Earth's L1 Lagrange Point about one million miles from Earth, where it remained for 886 days between 2001 and 2004, passively collecting solar-wind samples.JPL managed the Genesis mission for NASA's Science Mission Directorate, Washington. The Genesis mission was part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Alasca.

WELLINGTON, May 31 (Xinhua) -- New Zealand agricultural produce regulators cleared an Auckland-based firm that exported infant formula to China of food safety concerns, just hours after confirming they had launched an investigation.The clarification came the same day Kiaora New Zealand International, marketers of Heitiki infant formula, apologized for using a Maori name and icon on its product packaging.The Ministry of Agriculture and Forestry (MAF) issued a statement Tuesday to say Kiaora New Zealand had been cleared of food safety and export regulations concerns, but an investigation into the labeling and marketing of Heitiki would continue.The MAF issued a statement earlier Tuesday confirming reports it was investigating the product's safety, but MAF compliance and enforcement director Geoff Allen said in a later statement the investigation had been underway for about 10 days."The investigation was triggered by our internal surveillance. The investigation was primarily on whether there was a food safety issue, and I'm pleased to report that no food safety issues were identified," said Allen.Nothing "untoward" was identified in the origin and export destination of Heitiki-branded products, which were manufactured in New Zealand according to legal requirements, said Allen."The investigation has now turned to the labeling and marketing of the product. This aspect is ongoing, and seeks to identify anything in the labeling or marketing that is inaccurate or misleading.

BEIJING, Sept. 6 (Xinhuanet) -- NASA will launch on Thursday twin lunar orbiters built to map the gravity of Earth's moon in unprecedented detail, media reported Tuesday.The twin lunar probes, Graili-A and Graili-B, will blast off from Florida's Cape Canaveral Air Force Station at 8:37 a.m. EDT and at 9:16 a.m. EDT respectively Thursday, according to NASA.The Grail twins will travel three to four months to get to the moon under a slower but more economical plan.Artist concept of GRAIL mission. Grail will fly twin spacecraft in tandem orbits around the moon for several months to measure its gravity field in unprecedented detail.The two spacecrafts will reach the moon around New Year's Day when they will begin to probe the moon's composition from the crust to the core, according to NASA.The data collected by the probes will be used to better understand the moon's evolution and formation, NASA scientists said.Researchers will also use the twin probes to pinpoint the best landing sites for future explorations.The mission, from start to finish, costs 496 million U.S. dollars. The two Grail probes will crash into the moon after its mission.