阅读试题

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.

阅读试题

63. 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.

64. 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.

65. Which word can be used to complete the following process of changes?

A. protected

B. formed

C. exposed

D. combined

参考译文

有时医疗药物造成的伤害比他们的治疗效果更大。对于这个问题，一个解决方案是将药物置于胶囊内，让药品远离身体，也让身体远离药品，直到它们被释放在合适的地方。有很多方法来引发释放，包括改变温度、酸度等等。但是触发器会造成风险，例如烧伤。现在，加州的研究人员在设计一种迄今为止尚未出现的无害的触发器，那就是在药物胶囊上分布着闪亮的近红外线。

利用光线释放胶囊的药物并不新鲜。世界各地的研究人员已经开发出聚合物和其他材料，当它们吸收紫外线或可见光时，它们就开始分解。但组织也容易吸收紫外线和可见光，这就意味着药物的释放只能被光线可以到达的胶囊附近的皮肤所引发。近红外光谱光主要通过组织传播，所以研究人员一直试图用它来作为触发器。但很少有化合物能够吸收近红外线光谱，以及经历化学变化。

但是，去年那种情况有所改变改变，当加州大学圣地亚哥分校的化学家 Adah Almutairi报道说，她和她的同事们设计了一种吸收近红外线光谱光而分解的聚合物。因为他们的聚合物充分利用近红外线光谱吸收群，所以商用名为邻硝基苄基。当他们捕捉光线，邻硝基苄基组就脱离聚合物，并导致其崩溃。但邻硝基苄基只是一个平常的近红外光谱吸收器，当它有从聚合物中分离出来时，它可能对细胞有害。

所以Almutairi和她的同事们报道称发明了一种比胶囊更好的新材料。这一与长链聚合物相关的化合物称为甲酚团体。甲酚包含活性组件，使其在聚合物形态下极其不稳定，Almutairi和她的同事们把这一特点作为他们的优势。聚合甲酚后，他们限制每个带有吸光化合物的活性组件，并称其为六氯苯。六氯苯并吸收近红外光谱光时，活性组暴露并由长长的聚合物分解成两个短链。在这个断链上继续增加光线，可能释放胶囊里的任何药物。并且，Almutairi说，在吸收近红外光谱上，六氯苯是邻硝基苄基的10倍，并且它对细胞无害。

答案解析

63. B 考查细节理解。根据第一段最后一句”Now, researchers in Califomia 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.”再结合全文内容可知答案选B。

64. D 考查细节理解。根据第三段最后一句”But ONB is only a so-so NIR absorber, and it could be poisonous to cells when it separates from the polymer.”可知答案选D。

65. C 考查细节理解。根据最后一段中的”When the Bhcs absorb NIR light, the reactive groups are exposed...”可知C项正确。