大学生英语竞赛A类阅读理解专项强化真题试卷15

Scientists have cured color blindness in monkeys using gene therapy. As well as allowing color-blind humans to tell red from green, the innovative technique could restore sight to the blind. [*] Sufferers of age-related macular degeneration—the most common cause of blindness in the elderly—are among the millions who could eventually benefit. Researcher Jay Neitz said: “ If we could find a way to do this with complete safety in human eyes, as we did with monkeys, there would be a lot of people who would want it. We hope the technology will be useful in correcting a lot of different vision disorders. Professor Neitz used gene therapy—injections of genes—to allow two male squirrel monkeys called Sam and Dalton to see in full color for the first time. Like some humans with red-green colour blindness, the monkeys lacked a pigment that the cones—the colour—detector cells at the back of the eye—need to see red and green. As a result, they saw both red and green as shades of grey. Other colours, such as orange, blue and brown appeared washed-out. [*] To correct their vision, the US scientists injected the monkey’s eyes with millions of copies of a gene needed to make the missing pigment, the journal Nature reports. Importantly, the monkeys were injected with a human gene, suggesting the same technique would work on people. Four months later, their vision suddenly improved. Professor Neitz, of the University of Washington in Seattle, said; “it was as if they woke up and saw these new colours. They unquestionably responded to colours that had been invisible to them. “A version of the colour blindness test that is used in schools around the world showed just how much their vision has improved. Dr Katherine Mancuso, the study’s lead author, said: “Their performance on red and green was similar, but not quite as good, us a female monkey who had normal colour vision since birth. The need to prove that adding genes to the body does not cause harmful side-effects means it will be some time before the method is routinely used to correct colour blindness in humans. Despite this, the researchers are optimistic and point out that gene therapy is already being tested on Britons and Americans with a rare, hereditary form of blindness called Leber’s congenital amaurosis. The technique could also be adapted to treat other conditions that involve problems with genes in the colour and detail-detecting cone cells at the back of the eye. These include age-related macular degeneration, in which the deterioration of central vision makes it increasingly difficult to carry out everyday tasks such as reading and driving. Blindness linked to diabetes might also be treated. Cathy Yelf, of the Macular Disease Society, said the research was “very interesting“ but cautioned; “A practical gene therapy for macular degeneration is still some way off.

Rifts were already opening up in the G20 as China hit out at Britain and the US for demanding that China boost its imports of foreign goods. A senior official from the People’s Republic said it was not appropriate in a “market economy“ for a minister to call for a foreign nation to buy more of its products. Speaking at a briefing to reporters, Yu Jianhua of the Ministry of Commerce also described his country as “the biggest victim of protectionism“ by other countries. “ China has all along been making tremendous efforts to maintain a basic balance between exports and imports,“ he said. His remarks, made ahead of yesterday’s summit meeting, underlined the yawning divisions that: remain between world leaders despite pledges of a “global compact“ in Pittsburgh. Western powers like the UK and the US want China to bolster its domestic demand and increase imports as part of a “rebalancing“ of the world economy. They warn American consumers can no longer remain the primary engines of global demand as they bolster savings and repay debts. Leaders have agreed to boost the status of the G20 and increase the International Monetary Fund representation of China, India and other developing countries as part of the shift to more sustainable patterns of global growth. However, achieving a consensus on a way forward will be extremely difficult—not least because global bodies will still have no ability to dictate economic policy to members. Chancellor Alistair Darling said yesterday; “This does not mean we are in a new world order where we have a G2Q that tells everyone what to do. It is up to each country to decide what is best for them. On financial reform, yesterday’ s G20 deal will see restrictions on bonus payments and requirements forcing banks to hold more capital. Watchdogs will be able to limit payouts to a maximum share of a bank’ s revenue if it is necessary to strengthen the firm’ s finances. This stops far short of what French president Nicolas Sarkozy and other European leaders were seeking—a set monetary limit. Speaking during Saturday’s meetings, Mr Brown, the British prime minister, said; “The whole world community across the board is united in wanting to bring in rules and standards which will stamp out the bad practices of the past.

Getting a cold or catching the flu is a common complaint for people every year. In fact, people usually catch between two and five colds a year. No one enjoys the accompanying symptoms : the sore throat, runny nose, constant sneezing and headaches. Not surprisingly, cold medications have become a big business. People spend billions of dollars to combat this recurring problem. We see the number and variety of over-the-counter medicines each lime we enter a pharmacy. People estimate that, if you combine consume,“ purchases and drains on health care systems, at least 40 billion dollars are spent each year in the US alone. Is a cure for the common cold possible? The answer seems to be both yes and no. [*] First of all, the “common“ cold itself is not a single disease. Any of two hundred different viruses could be responsible for the symptoms of a cold. Developing a vaccine for the common cold would literally mean having to develop hundreds of vaccines. Additionally, some cold viruses have the ability to change their molecular composition. Thus, even though our bodies may become immune to a certain cold virus this winter, by next winter our antibodies will probably not recognize it. However, one family of viruses, the rhinoviruses, seems to account for almost 40% of all colds. Therefore, scientists have been focusing their research on this family of viruses in the hopes that, treatments targeting rhinoviruses will result in a drastic decrease in the number of colds people get. In the late 1990s searchers experienced some initial success. Biologists developed a treatment, an anti-viral molecule called BIRR4, which prevented the binding of the virus to cells in the nose. This binding is an essential first step in stopping a viral infection and, was it preventable, many infections would be by-passed. For the next few years, the pharmaceutical giant Boehringer tried to make this treatment commercially viable. Unfortunately, they found to their dismay that this treatment only worked just prior to getting a cold or in the first stages of infection, when most people do not yet realize any thing is wrong. As a possible treatment for a cold, it was severely limited and so in 2000. Boehringer dropped the BIRR4 project. Another difficulty in finding a cure for the common cold is that the cold virus does not actually cause our cold symptoms. Indeed, by the time we start to show cold symptoms, the viral infection is almost over. Most infections result in no symptoms at all. The symptoms that we get from a cold are, in reality, produced by our body’ s immune response, not by the virus itself. One way the body fights infection is with an anti-inflammatory response. Part of this response is to dilate blood vessels in the affected area and to make the affected cells release fluid to the surrounding area. In cold, this results in the swelling of the nose and throat, as well as sneezing and a runny nose. This also very similar to how the body reacts when we have allergies. Thus, some scientists are now suggesting targeting the body’s immune responses rather than the virus itself, as we do when we treat allergies. One medical researcher suggests that in order to find a cure for colds we must weaken our immune system’s response. Through a cocktail of certain drugs—interferon, ibuprofen and chlorpheniramine—cold sufferers would be able to decrease the anti-inflammatory part of the immune response and get rid of their symptoms, while still allowing their bodies to fight off the remaining viral infection. Ibuprofen and chlorpheniramine are both inexpensive and available over the counter. Unfortunately, however, a single dose of interferon is about $200 and is as yet unavailable in large over-the-counter quantities. Though at times it has seemed that a cure was tantalizingly close, this process of infection and our bodies’ response to it is clearly more complicated than previously guessed. Undoubtedly, the search tor a cure for the common cold will continue. What form this eventual cure will take though, is anyone’ s guess.

A common complaint for people each year is catching a cold. Many uncomfortable symptoms accompany a cold. Each year, cold sufferers spend millions to【71】______this recurring problem. Any of two hundred different【72】______could cause a cold. Even though our bodies may become【73】______to a certain cold virus this winter, by next winter our antibodies will probably not recognize it. However, rhinoviruses account for 40% of the colds we catch. Treating that family of viruses would drastically decrease the number of colds we catch each year. Some scientists are now suggesting【74】______the body’s immune responses rather than the virus itself. One researcher suggests that to find a cure for colds we must weaken our immune system’s【75】______.

Space enthusiasts hoping to become China s next astronauts must pass “super human “ health checks. . . and that means no bad breath. [*] New “taikonauts“ must also have brushed their teeth thoroughly over the years as anyone with dental cavities is disqualified. And even if an individual is fighting fit, he won’ t be selected if there has been any serious illness in the last three generations of his family. These are amongst the 100 health requirements for would-be astronauts vying to he part of China ’ s next space team, according to the Yangtse Evening Paper. [*] The selection process, which the paper said is for the second batch of Chinese astronauts, will disqualify those who have scars, runny noses, ringworm, drag allergies or bad breath. ’“The bad smell would affect their fellow colleagues in the confined space,“ said Shi Bingbing, an official at one of the six astronaut health screening hospitals in Nanjing. Aside from the physical requirements of the job, the candidate must also possess a pleasant and adaptable disposition, the paper said. “These astronauts could be regarded as super human beings,“ Shi said. China became the third country with a successful manned space programme after they sent an astronaut into space aboard Shenzhou 5 on October 15, 2003, for more than 21 hours. China’ s first manned space-walk occurred in Septeinher last year. Zhai Zhigang, the son of a snack-seller, unveiled a small Chinese flag in space, helped by his colleague Liu Boming, who also briefly popped his head out of the capsule. The space walk was a step towards China ’ s longer-term goal of assembling a space lab and then a larger space station.

ST. LOUIS—It’s no secret that raising children’ can be expensive, but how about a quarter of a million dollars expensive? [*] A government report released Tuesday said a middle-income family with a child born last year will spend about $ 221 ,000 raising that child until the age of 17. The report by the US Department of Agriculture’ s Center for Nutrition Policy and Promotion identified housing as the largest single expense, followed by food and child care/education costs. The $ 221 ,000 in expenses rises to about $292,000 when adjusted for inflation. USDA economist Mark Lino, who co-authored the report with Andrea Carlson, often hears people say children cost a lot when the annual findings are issued. “I tell them children also have many benefits, so you have to keep that in mind,“ he said. Families with more income spend more on child-related costs, the report said. A family that earns Jess than $57,000 annually will spend about $ 160,000 on a child from birth until the end of high school. Those with an income between $57,000 and $99,000 spend about $221 ,000, and those with higher incomes spend roughly $ 367 ,000. Costs of raising a child are highest in the urban Northeast and lowest in the urban South and rural areas. The USDA report helps courts and states determine child-support guidelines and foster-care payments. It does not address costs specifically related to childbearing and paying for college. One of the largest changes over time has been the increase in costs related to care for young children. The report first was issued in 1960, when such costs were largely negligible, but with more working families turning to outside help with child care, it has grown to be a significant expense for many families. The report does not give total costs related to early child care. Raben Andrews, a mother of three in St Louis, said the government figures sounded right to her. “Well, that’ s not half of it,“ the 42-year-old schoolteacher joked. “I still have to put the little devils through college.