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SSS 2011-11-03

时间:2011-12-02 05:48来源:互联网 提供网友:gmeng   字体: [ ]
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    (单词翻译:双击或拖选)

 This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute.

 
They say what doesn't kill you makes you stronger. But sometimes what makes you stronger can kill you, at least when it comes to blood clotting2. Because the stickiness that allows platelets to heal your wounds also raises your risk of heart attack. 
 
All mammals use platelets to help prevent blood loss after traumatic injury. But birds don't have 'em, nor do reptiles3 or fish. Instead, these critters have blood cells called thrombocytes, which are about twice the size of platelets. But is bigger necessarily better when it comes to clotting? Scientists took thrombocytes from parakeets and put them to the test. The work appears in the journal Blood.
 
They focused their attention on birds because our feathered friends have a cardiovascular system much like our own, in that blood exerts pressure on the blood vessel4 walls. 
 
The results: parakeet thrombocytes don't stick together like platelets do. They also don't block blood flow in the birds' arteries5 the same way that platelets do when they form clots6 in mice. 
 
Which means that mice may be more likely to survive a bloodletting-pecking. But birds are far less likely to suffer from the clot1 forming economy class syndrome—despite being frequent fliers.
 
Thanks for the minute. For Scientific American's 60-Second Science, I'm Karen Hopkin.

点击收听单词发音收听单词发音  

1 clot nWEyr     
n.凝块;v.使凝成块
参考例句:
  • Platelets are one of the components required to make blood clot.血小板是血液凝固的必须成分之一。
  • The patient's blood refused to clot.病人的血液无法凝结。
2 clotting 9eca3747f25ae6f0d50d00d5b71d5d7d     
v.凝固( clot的现在分词 );烧结
参考例句:
  • The study was also based only on the one anti-clotting drug. 所用抗血栓药物也仅限于一种。 来自互联网
  • A plasma protein that is converted into thrombin during blood clotting. 凝血原酶一种血浆蛋白质,在血液凝聚时转化成凝血''。'酵'。''''。'素'。''。 来自互联网
3 reptiles 45053265723f59bd84cf4af2b15def8e     
n.爬行动物,爬虫( reptile的名词复数 )
参考例句:
  • Snakes and crocodiles are both reptiles. 蛇和鳄鱼都是爬行动物。 来自《简明英汉词典》
  • Birds, reptiles and insects come from eggs. 鸟类、爬虫及昆虫是卵生的。 来自《现代汉英综合大词典》
4 vessel 4L1zi     
n.船舶;容器,器皿;管,导管,血管
参考例句:
  • The vessel is fully loaded with cargo for Shanghai.这艘船满载货物驶往上海。
  • You should put the water into a vessel.你应该把水装入容器中。
5 arteries 821b60db0d5e4edc87fdf5fc263ba3f5     
n.动脉( artery的名词复数 );干线,要道
参考例句:
  • Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
  • This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》
6 clots fc228b79d0fbd8618ecc4cda442af0dd     
n.凝块( clot的名词复数 );血块;蠢人;傻瓜v.凝固( clot的第三人称单数 )
参考例句:
  • When you cut yourself, blood clots and forms a scab. 你割破了,血会凝固、结痂。 来自《简明英汉词典》
  • Milk clots when it turns sour. 奶变酸就凝块。 来自《现代英汉综合大词典》
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