C

　　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 near­infrared 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 NIR­absorbing group called

【五年高考（2011-2015）英语试题分项精解：专题23 阅读理解之科普知识类（原卷版）】相关文章：

★ 重庆市2014高考英语阅读理解一轮（精品）训练题（1）附答案

★ 【三维设计】2017届高考英语（江苏专用）二轮复习阅读理解解题技法示范课件：3

★ 贵州省贵阳市2014高考英语（新人教版）一轮阅读训练（24）附答案

★ 2017届高考英语二轮复习大题冲关秘籍完形填空之夹叙夹议文：名校模拟（含解析）

★ 2017届高考英语二轮复习大题冲关秘籍语法填空：命题分析（含解析）

★ 2017届高考英语二轮复习课时训练：12（含解析）

★ 2017年高考英语二轮复习精品资料：专题16 书面表达（教学案）（教师版）

★ 2017届高考英语二轮复习课时训练：11（含解析）

★ 湖南省长沙县实验中学2016届高三英语二轮复习书面表达复习重点话题指导专题21 语言学习话题指导（学生版）

★ 2016年高考【英语】学科试题评析（四川卷）