Researchers around the globe have developed polymers (聚合物) and other materials that begin to break down when they absorb either ultraviolet (UV, 紫外线) or visible light. But tissues also readily absorb UV and visible light, which means the drug release can be triggered only near the skin, where the light can reach the capsule. NIR light largely passes through tissues, so researchers have tried to use it as a trigger. But few compounds (化合物) absorb NIR well and go through chemical changes.
That changed last year when Adah Almutairi, a chemist at the University of
California, San Diego, reported that she and her colleagues had designed a polymer that breaks down when it absorbs NIR light. Their polymer used a commercially available NIR-absorbing group called o-nitrobenzyl (ONB). When they catch the light, ONB groups fall off the polymer, leading to its breakdown. But ONB is only a so-so NIR absorber, and it could be poisonous to cells when it separates from the polymer.
So Almutairi and her colleagues reported creating a new material for capsules
that's even better. This one consists of a long chain of compounds called cresol groups linked in a polymer. Cresol contains reactive (易反应的) components that make it highly unstable in its polymeric form, a feature Almutairi and her colleagues use to their advantage. After polymerizing the cresols, they cap each reactive component with a light-absorbing compound called Bhc. When the Bhcs absorb NIR light, the reactive groups are exposed and break the long polymer into two short chains. Shining additional light continues this breakdown, potentially releasing any drugs in the capsule. What's more, Almutairi says, Bhc is 10 times better at absorbing NIR than is ONB and is not poisonous to cells.
1. According to the passage, which of the following could be the best trigger? A. Temperature change. B. NIR light. C. Acidity change. D. UV light. 2. Why is ONB unsatisfactory?
A. It breaks down when it absorbs NIR light.
B. It falls off the polymer and triggers drug release. C. It has not come onto the market up till now. D. It is not effective enough and could be poisonous.
3. Which word can be used to complete the following process of changes? Bhcs absorb NIR.?Part of the cresol is .?Polymer breaks down.?Drug is released.
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A. protected B. formed C. exposed D. combined
【要点综述】这是一篇科技文。怎样使用胶囊？如何让吃药更加安全、疗效更好？文章对此做了介绍。
1. B 信息理解题。根据第一段最后一句“Now, researchers in California have designed what could be a harmless trigger to date: shining near-infrared light (NIR，近红外线) on the drug in the capsule.”可知答案。
2. D 推理判断题。根据第三段最后两句“?ONB groups fall off the polymer,
leading to its breakdown.”和“?and it could be poisonous to cells?”可知答案。
3. C 信息理解题。根据最后一段第五句“When the Bhcs absorb NIR light, the
reactive groups are exposed and break the long polymer into two short chains.”可知此处用exposed，即C项正确。
阅读下列四篇短文，从每小题后所给的A,B,C或D四个选项中，选出最佳选项。
Do you know how it is when you see someone yawn and you start yawning too? Or how hard it is to be among people laughing and not laugh yourself? Well, apparently it’s because we have mirror neurons (神经元) in our brains.
Put simply, the existence of mirror neurons suggests that every time we see someone else do something, our brains imitate (模仿) it, whether or not we actually perform the same action. This explains a great deal about how we learn to smile, talk, walk, dance or play sports. But the idea goes further: mirror neurons not only appear to explain physical actions, they also tell us that there is a biological basis for the way we understand other people.
Mirror neurons can undoubtedly be found all over our brains, but especially in the areas which relate to our ability to use languages, and to understand how other people feel. Researchers have found that mirror neurons relate strongly to language. A group of researchers discovered that if they gave people sentences to listen to (for example: “The hand took hold of the ball”) , the same mirror neurons weretriggered as when the action was actually performed (in this example, actually taking hold of a ball) .
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Any problems with mirror neurons may well result in problems with behavior. Much research suggests that people with social and behavioral problems have mirror neurons which are not fully functioning. However, it is not yet known exactly how these discoveries might help find treatments for social disorders.
Research into mirror neurons seems to provide us with ever more information concerning how humans behave and interact (互动) . Indeed, it may turn out to be the equivalent (相等物) for neuroscience of what Einstein’s theory of relativity was for physics. And the next time you feel the urge to cough in the cinema when someone else does—well, perhaps you’ll understand why. 1. Mirror neurons can explain . A. why we cry when we are hurt
B. why we cough when we suffer from a cold C. why we smile when we see someone else smile D. why we yawn when we see someone else stay up late
2. The underlined word“triggered”in the third paragraph probably means“ ”. A. set off B. cut off C. built up D. broken up 3. We can learn from the passage that mirror neurons . A. relate to human behavior and interaction B. control human physical actions and feelings C. result in bad behavior and social disorders D. determine our knowledge and language abilities 4. What is the passage mainly about?
A. Ways to find mirror neurons. B. Problems of mirror neurons. C. Existence of mirror neurons. D. Functions of mirror neurons. 【参考答案】1—4、CAAD
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