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Medical drugs sometimes cause more damage than they cure. One solution to this p

Medical drugs sometimes cause more damage than they cure. One solution to this p

题文


Medical drugs sometimes cause more damage than they cure. One solution to this problem is to put the drugs inside a capsule, protecting them from the body—and the body from them—until they can be released at just the right spot. There are lots of ways to trigger (引发) this release, including changing temperature, acidity, and so on. But triggers can come with their own risks—burns, for example. 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.
The idea of using light to liberate the drug in the capsule isn’t new. 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.
小题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.小题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.小题3:Which word can be used to complete the following process of changes?A.protectedB.formedC.exposedD.combined 题型:未知难度:其他题型

答案


小题1:B
小题2:D
小题3:C

解析

这一篇科普文章,讲的是“怎样使用胶囊,让吃药更加安全、疗效好”。
小题1:细节推理题。根据首段最后两句“But triggers can come with their own risks-…”“Now, …a harmless trigger…near-infrared light (NIR, 近红外线)”可知答案是B。
小题2:细节理解题。根据第三段尾句“But ONB is only a so-so NIR absorber, and it could be poisonous to cells when it separates from the polymer.”
小题3:细节归纳题。根据尾段关键词、句:“a long chain of compounds called cresol groups”“Cresol contains reactive(易反应的) components that…”“When…, the reactive groups are exposed and break…”“…continues this breakdown”可知答案是C。

考点

据考高分专家说,试题“Medical drugs someti.....”主要考查你对 [健康环保类阅读 ]考点的理解。

健康环保类阅读

健康环保累阅读概念:

健康环保类文章常是介绍科学知识、生活常识和环境保护方面的短文。体裁有记叙文、 说明文、议论文和各种应用文。

健康环保类文章阅读技巧:

   健康环保类文章常是介绍科学知识、生活常识和环境保护方面的短文。阅读此类短文要以现象或事物为中心进行思考,理解现象产生的原因、条件和客观规律等。同时要抓住事物的特征、用途和相互关系等。科普环保类文章一般为说明文,从结构上看大致可分为三个部分:
   第一部分一般是文章的首段,主要用来提出文章的主题,即文章想要阐述、说明的主要内容;
   第二部分是文章的主体,可由若干个段落组成,对文章的主题进行展开说明;
   第三部分是结尾段,对文章的主题进行归纳总结。这类文章多用一般现在时,而且一般多使用客观性词语表述。有时为了强调客观性,也常使用被动语态。
   从近几年的考试题来看,科普环保类的文章越来越与人们的实际生活相接近。由于此类文章缺乏故事情节,很多同学对此类文章感到费解。但一般的科普类文章都是就事论事,需要逻辑推理和想象的时候较少,因此此类阅读题也没有同学们想象中的那么难,只要多加训练,就能较好地答题。
【阅读策略】
1、概要(Summarizing):
  阅完材料后,将所阅材料浓缩,摘要,做出所阅材料的书面或口头梗概。
2、组织(Organization):
  阅读后根据阅读内容,识别观点、人物、事件之间的关系以及文章的结构关系。如:时间关系、比较或对比关系、相关关系及因果关系等。

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