中山痔疮症状是什么(中山市混合痔) (今日更新中)

WASHINGTON, Nov. 10 (Xinhua) -- Using its near-infrared vision to peer nine billion years back in time, NASA's Hubble Space Telescope has uncovered an extraordinary population of young dwarf galaxies brimming with star formation, the U.S. space agency announced on Thursday.While dwarf galaxies represent the most common type of galaxy in the universe, the rapid star-birth observed in these newly- found examples may force astronomers to reassess their understanding of the ways in which galaxies form.The galaxies are a hundred times less massive, on average, than the Milky Way, yet they churn out stars at such a furious pace that their stellar content would double in just 10 million years. By comparison, the Milky Way would take a thousand times longer to double its star population.The universe is estimated to be 13.7 billion years old, and these newly-discovered galaxies are extreme even for the young universe -- when most galaxies were forming stars at higher rates than they are today. Astronomers using Hubble's instruments could spot the galaxies because the radiation from young, hot stars has caused the oxygen in the gas surrounding them to light up like a bright neon sign."The galaxies have been there all along, but up until recently astronomers have been able only to survey tiny patches of sky at the sensitivities necessary to detect them," said Arjen van der Wel of the Max Planck Institute for Astronomy in Germany, lead author of a paper on the results to be published online on Nov. 14 in The Astrophysical Journal. "We weren't looking specifically for these galaxies, but they stood out because of their unusual colors. "The observations were part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), an ambitious three- year study to analyze the most distant galaxies in the universe. CANDELS is the first census of dwarf galaxies at such an early epoch."In addition to the images, Hubble has captured spectra that show us the oxygen in a handful of galaxies and confirmed their extreme star-forming nature," said co-author Amber Straughn at NASA's Goddard Space Flight Center. "Spectra are like fingerprints. They tell us the galaxies' chemical composition."The CANDELS team uncovered the 69 young dwarf galaxies in near- infrared images taken with Hubble's Wide Field Camera 3 and Advanced Camera for Surveys.The observations suggest that the newly-discovered galaxies were very common nine billion years ago. However, it is a mystery why the newly-found dwarf galaxies were making batches of stars at such a high rate.

BEIJING, Jan. 17 (Xinhuanet) -- India has reported the first case of "totally drug-resistant tuberculosis," a long-feared and virtually untreatable form of the killer lung disease.Similar highly resistant cases have been noted before. In 2003, two Italian women died and there were 15 cases reported from Iran in 2009. That same year, The Associated Press reported on a case of a Peruvian teenager who was infected at home but diagnosed while visiting Florida.Such kind of TB has mostly been limited to impoverished areas, and has not spread widely. But experts believe there could be many undocumented cases.No one expects the Indian TB strains to rapidly spread elsewhere.The airborne disease is mainly transmitted through close personal contact and isn't nearly as contagious as the flu. Indeed, most of the cases of this kind of TB were not from person-to-person infection but were mutations that occurred in poorly treated patients.The Indian hospital that saw the initial cases tested a dozen medicines and none of them worked. A TB expert at the U.S. Centers for Disease Control and Prevention said they do appear to be totally resistant to available drugs."It is concerning," said Dr. Kenneth Castro, director of the CDC's Division of Tuberculosis Elimination. "Anytime we see something like this, we better get on top of it before it becomes a more widespread problem."Ordinary TB is easily cured by taking antibiotics for six to nine months. However, if that treatment is interrupted or the dose is cut down, the stubborn bacteria battle back and mutate into a tougher strain that can no longer be killed by standard drugs. The disease becomes harder and more expensive to treat.Tuberculosis is an age-old scourge that lies dormant in an estimated one in three people. About 10 percent of those people eventually develop active TB, which kills roughly 2 million a year, according to WHO. Each victim infects an average of 10 to 15 others every year, typically through sneezing or coughing.If a TB case is found to be resistant to the two most powerful anti-TB drugs, the patient is classified as having multi-drug-resistant TB (MDR). An even worse classification of TB — one the WHO accepts — is extensively drug-resistant TB (XDR), a form of the disease that was first reported in 2006 and is virtually resistant to all drugs.About 20 percent of the world's multi-drug-resistant cases were found in India, which is home to a quarter of all types of tuberculosis cases worldwide.

WASHINGTON, Nov. 10 (Xinhua) -- The U.S. Food and Drug Administration (FDA) has sent warning letters to more than 1,200 retailers, the majority of which respond to violations relating to selling tobacco to minors, as part of its ongoing effort to reduce tobacco use among children, the agency announced Thursday in a statement.The FDA said that while most retail establishments have been found to be in compliance with the law, some retailers are still selling cigarettes and smokeless tobacco to minors. Warning letters may be followed by civil money penalties if retailers continue to violate the law."It should worry every parent that 20 percent of U.S. high school students smoke cigarettes," said FDA Commissioner Margaret Hamburg in a statement. "President Obama and the FDA are committed to preventing children from smoking. For many young people, that first cigarette or use of smokeless tobacco will lead to a lifetime of addiction, and for many, serious disease. More than 80 percent of adult smokers begin smoking before 18 years of age. Retailers are vital partners in the FDA's efforts to prevent tobacco use among kids."Obama signed the Family Smoking Prevention and Tobacco Control Act that gives the FDA authority to regulate tobacco products to prevent use by minors and reduce the impact on public health. One of the law's provisions permits the FDA to contract with states and territories to conduct compliance check inspections of tobacco retailers. In 2011, the FDA awarded compliance contracts totaling more than 24 million U.S. dollars to 38 states.The FDA also began inspecting U.S. tobacco product manufacturers in October 2011. This is the first time tobacco product manufacturing facilities have ever been inspected by a federal public health agency.

WASHINGTON, Oct. 9 (Xinhua) -- U.S. researchers have found a way to block, in an animal model, the damaging inflammation that contributes to many disease conditions. In their report receiving early online publication Sunday in Nature Biotechnology, researchers describe using small interfering RNA technology to silence the biochemical signals that attract a particular group of inflammatory cells to areas of tissue damage."The white blood cells known as monocytes play a critical role in the early stages of the immune response," says Matthias Nahrendorf, of the Massachusetts General Hospital (MGH) Center for Systems Biology, the paper's senior author. "We now know there are two subsets of monocytes -- an inflammatory subset that defends against pathogens and a reparative subset that supports healing. But if the inflammatory response is excessive, it can block the healing process and exacerbate conditions such as heart disease and cancer."Cells damaged by injury or disease release a cocktail of chemicals called cytokines that attract immune cells to the site of the damage. Inflammatory monocytes are guided to sites of tissue injury by a receptor protein called CCR2, and the MGH-led team devised a strategy targeting that molecule to block the inflammatory process but not the action of the reparative monocytes.Small interfering RNA (siRNA) technology prevents production of specific proteins by binding to associated messenger RNA molecules and preventing their translation. However, the technique requires extreme precision in developing the right siRNA molecule and delivering it to the correct cellular location.To make sure that their siRNA preparation targeted the right monocytes, researchers first confirmed that its use reduced levels of CCR2 in monocytes and increased levels of the fragments produced when siRNA binds to its target. They then showed that monocytes from mice treated with the siRNA preparation were unable to migrate towards CCR2's usual molecular target. Experiments in animal models of several important diseases showed that the siRNA preparation reduced the amount of cardiac muscle damaged by a heart attack, reduced the size and the number of inflammatory cells in atherosclerotic plaques and in lymphomas, and improved the survival of transplanted pancreatic islets."These inflammatory monocytes are involved in almost every major disease," Nahrendorf explains. "Anti-inflammatory drugs currently on the market hit every inflammatory cell in the body, which can produce unwanted side effects. This new siRNA treatment doesn't affect inflammatory cells that don't rely on the CCR2 receptor. That makes a big difference."

SAN FRANCISCO, Nov. 3 (Xinhua) -- Hewlett-Packard Co. (HP) on Thursday introduced its Slate 2 Tablet PC, a business-targeted tablet computer running Windows operating system.Looking like the previous version, Slate 2, featuring an 8.9- inch screen, is upgraded with Intel Atom Z670 processor to deliver faster boot times and improved battery life up to six hours, said HP.It also has a Bluetooth keyboard dock and Swype keyboard which allows users to enter words by sliding a finger or stylus from letter to letter, lifting only between words.The device will be available to customers worldwide for 699 U.S. dollars later this month, according to HP.Slate 500, Slate 2's previous generation running Windows, was introduced last October and sold exclusively to businesses for 800 dollars upon launch.HP said in a statement that the Slate 2 tablet provides instant deployment for business and vertical markets such as education, healthcare, government and retail, where jobs frequently take users away from a traditional desk.The company on Thursday also announced HP 3115m, a new notebook PC targeting business, education and government customers. The notebook will be available in the Americas only next Friday with prices staring at 429 dollars.HP's consumer-oriented tablet TouchPad was killed off in August before former chief executive officer Leo Apotheker resigned. A dropped price from 499 to 99.99 dollars has made the unpopular device sold out in stores across the U.S. and Canada in days.Last Thursday, HP announced it will keep its PC business, saying it will build tablets running Microsoft's upcoming Windows 8 system in 2012.

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