中山肛内出血(中山内痔在线咨询) (今日更新中)

CANBERRA, Sept. 7 (Xinhua) -- A team of Australian and U.S. scientists on Wednesday said they discovered a genetic defect, which can lead to Leigh syndrome, a rare disorder which affects the central nervous syndrome.The scientists tested more than 1000 genes by encoding proteins active in two individuals who suffer from the illness. They used a new technique known as next-generation DNA sequencing to examine the genes.The gene they discovered encodes an enzyme which is found in the mitochondria which are subsets of cells. Without this enzyme the mitochondria do not translate proteins efficiently, and this then causes Leigh syndrome.According to David Thorburn, from the Murdoch Children's Research Institute in Melbourne, the discovery shows the enormous potential of the new technology."These findings demonstrate the ability of sequencing technologies to improve diagnosis," Professor Thorburn said in a statement released on Wednesday."Although it isn't clear in the case of Leigh syndrome whether the precise molecular diagnosis will necessarily lead to therapies, the current findings represent a meaningful service."He added that diagnosis of the disease along with its specific genetic cause can also be informative about the risk a couple has of having another affected child. The diagnostic information can help in decisions about whether and how to pursue alternative means of having children, for instance through the use of donor sperm or eggs.The research team consisted of scientists from Australia's Murdoch Institute as well as the Broad Institute in the U.S.In Leigh syndrome, infants are born apparently healthy only to develop movement and breathing disorders that worsen over time, often leading to death by the age of three. The problem is that the mitochondria responsible for powering their cells cannot keep up with the demand for energy in their developing brains.

SAN FRANCISCO, July 15 (Xinhua) -- U.S. microblogging platform Twitter on Friday marked its fifth anniversary since public debut."Twitter, then called Twttr, opened to the public five years ago today," the company said in a Tweet, a short message within 140 characters users are allowed to communicate on the website."Twttr is a new mobile service that helps groups of friends bounce random thoughts around with SMS," co-founder Biz Stone described the service in a blog post on July 13, 2006, two days before its public debut."There were 224 Tweets sent on July 15, 2006. Today, users send that many Tweets in less than a tenth of a second," said the San Francisco-based company.Twitter said more than 600,000 new users signed up on Thursday while it took it more than 16 months to reach the first 600,000 Twitter accounts.The tipping point for the service's popularity was the 2007 South by Southwest festival, a set of film, interactive and music festivals and conferences that take place every March in Austin, Texas. During the event, the Tweets sent per day grew from 20,000 to 60,000.With an estimated user base of 200 million worldwide, some 200 million Tweets are generated and 1.6 billion search queries are handled every day, the company said.According to research firm EMarketer, advertising sales on Twitter is expected to reach 150 million U.S. dollars this year. SharesPost, a secondary market for privately held companies, has assessed Twitter's current worth at 6.8 billion dollars.

BEIJING, Aug. 1 (Xinhua) -- The provinces of Guizhou and Hunan reported their lowest levels of precipitation since 1951 in July, the China Meteorological Administration (CMA) said on Monday.Precipitation levels across the country saw a decrease of 8.7 percent from the average level of 115.9 mm in July, the lowest levels seen in 11 years, said Chen Zhenlin, an expert with the CMA.The average temperature recorded across the country in July was 22.1 degrees Celsius, up 0.7 degrees Celsius from the average level.

GUANGZHOU, Aug. 2 (Xinhua) -- China conducted a scientific survey of the southwest basin of the South China Sea around the end of July, the China Geological Survey (CGS) said on Tuesday.The expedition acquired a "high-quality integrative geographic profile" of the basin's 1,000-km-long survey line, which stretches from the region's Xisha Islands to the Nansha Islands, according to a press release from the CGS.The expedition allows scientists to study the evolution of tectonic activity in the South China Sea and predict disasters such as earthquakes and tsunamis, the CGS said.The survey is also of significance for countries around the South China Sea, as they will be able to use the data to enhance their ability to prevent and reduce the effects of disasters, it said.The survey lasted from June 13 to July 31 and was carried out by the Chinese research vessel Tanbao in collaboration with a French research unit. Recent typhoons prevented the researchers from surveying part of the region, therefore some data is yet to be supplied later, the CGS said.

来源：资阳报