题目:
下列哪种移植术后,受者对移植物不可避免地会发生强烈的排斥反应()
A.异种移植术
B.自体移植术
C.同种移植术
D.同质移植术
E.以上都不是
答案:
参考答案:A
下列哪种移植术后,受者对移植物不可避免地会发生强烈的排斥反应()
A.异种移植术
B.自体移植术
C.同种移植术
D.同质移植术
E.以上都不是
参考答案:A
医生为了反应病人体温变化情况,一般绘制______统计图.
下列属于影响社会和谐的问题有[ ]
①城乡、区域、经济社会发展很不平衡
②人口资源环境压力加大
③一些人诚信缺失、道德失范
④就业、社会保障、收入分配、教育、住房、安全生产、社会治安等方面关系群众切身利益的问题比较突出
A、①②
B、③④
C、①②④
D、①②③④
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.protected
B.formed
C.exposed
D.combined
“生长说”的代表人物是()
A.格罗斯
B.斯宾塞
C.阿普利登
D.皮亚杰
某村实行“村务公开制度”和建立“村务监督委员会”等做法促进了当地经济社会发展。
如果要将上述事实写成新闻报道,你认为最合适的标题是()。
A.扩大村民民主监督权利的主要途径
B.公民监督基层政府权力的有效形式
C.完善基层群众自治制度的积极探索
D.加强我国基层 * * 建设的深刻实践