东营大型工业吸尘器(滁州大功率工业吸尘器) (今日更新中)

WASHINGTON, July 20 (Xinhua) -- The loss of a protein that coats sperm may explain a significant proportion of infertility in men worldwide, according to a study by an international team of researchers led by University of California Davis.A paper describing the work was published Wednesday in the journal Science Translational Medicine. The research could open up new ways to screen and treat couples for infertility.The gene DEFB126 encodes a protein called Beta Defensin 126, which coats the surface of sperm and helps it penetrate cervical mucus in the female. A survey of samples from the U.S., Britain and China showed that as many as a quarter of men worldwide carry two copies of the defective gene.In the new study, researchers found that men with a muted DEFB126 lack Beta Defensin 126, making it much more difficult for sperm to swim through the mucus and eventually join with an egg.Examining 500 newly married Chinese couples, researchers found that the lack of Beta Defensin 126 in men with the DEFB126 mutation lowered fertility (even among men that did not display other deficiencies usually associated with infertility, like inadequate semen volume and low sperm motility). Wives of men with the Beta Defensin 126 variant were significantly less likely to become pregnant than were other couples, and 30 percent less likely to have a birth.This genetic variation in DEFB126 likely accounts for many unexplained cases of infertility, researchers say. They hope next to work with a major infertility program in the U.S. to further explore the role of the mutation.

LOS ANGELES, July 5 (Xinhua) -- NASA's Juno spacecraft is 30 days away before its first launch window opens, the Jet Propulsion Laboratory (JPL) announced on Tuesday."One month from today, our first launch window opens at 11:34 a. m. EDT (8:34 a.m. PDT) and lasts 69 minutes," said Jan Chodas, Juno project manager from NASA's JPL in Pasadena, Los Angeles."Our primary launch period is 22 days long, and so if weather or other issues come up on Aug. 5, we have 21 more days to get Juno flying. Once we get Juno into space, it's a five-year cruise to Jupiter.""The launch window is the length of time allotted every day for an attempt to launch the spacecraft," said Chodas. "The launch period is the period of time in days when everything is in the right place to get your mission off to the right start."For a mission like Juno, getting everything in the right place includes considering the size of the rocket and spacecraft, where our home planet -- and in particular Juno's launch pad -- is pointed at any moment, and its location in space relative to other celestial objects like Juno's final target, Jupiter.Juno is scheduled to launch aboard a United Launch Alliance Atlas V rocket from pad 41-C at the Cape Canaveral Air Force Station, Florida.The solar-powered spacecraft will orbit Jupiter's poles 33 times to find out more about the gas giant's origins, structure, atmosphere and magnetosphere and investigate the existence of a solid planetary core.JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio.The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Alaska. Lockheed Martin Space Systems, Denver, built the spacecraft.

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.

BEIJING, Aug. 12 (Xinhuanet) -- Engineers at the University of Illinois have unveiled novel, skin-mounted electronics whose circuitry bends, wrinkles, and even stretches with skin, according to media reports quoting the Science Friday.The device platform includes electronic components, medical diagnostics, communications, and human-machine interfacing on a patch so thin and durable that it can be mounted to skin much like a temporary tattoo, the jounral described.What's more, the engineers demonstrated the invention across a wider range of components, including LEDs, transistors, wireless antennas, sensors, and conductive coils and solar cells for power."We threw everything in our bag of tricks onto that platform, and then added a few other new ideas on top of those to show that we could make it work," said engineering professor John A. Rogers in a news release.

SAN FRANCISCO, June 9 (Xinhua) -- Hewlett-Packard Co. (HP) on Thursday announced that its tablet computer, HP TouchPad, will go on sale in the United States on July 1.Two versions of HP TouchPad, with the option of either 16 gigabytes or 32 gigabytes of internal storage, and both only with Wi-Fi connection, will be available in the United States for 499. 99 U.S. dollars and 599.99 dollars respectively, the company said in a statement.The product will hit stores in Britain, Ireland, France and Germany a few days later and in Canada in mid-July, with availability scheduled to follow later this year in Italy, Spain, Australia, China's Hong Kong, New Zealand and Singapore.Preorders in North America and Europe will begin on June 19, HP said.HP did not release the price details when it introduced TouchPad on Feb. 9. The black device, with a 9.7-inch touch screen, runs webOS operating system, a mobile platform developed by Palm, a smartphone maker acquired by HP last April for 1.8 billion dollars.

来源：资阳报