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SSS 2011-10-07

时间:2011-11-01 07:53来源:互联网 提供网友:gmeng   字体: [ ]
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 PCR—the polymerase chain reaction—is a crucial tool. The DNA1 amplification2 technique is used in genome sequencing, forensics and the diagnosis3 of various diseases.

 
To give researchers more genetic4 material to work with, a PCR instrument repeatedly heats and cools an original biological sample. Which gives enzymes5 a chance to replicate6 the DNA millions of times so it can be more easily analyzed7.
 
Such sequence amplification would be a boon8 to diagnosis in a doctor's office—especially when an infectious disease is spreading rapidly. Unfortunately, genetic tests usually take a day or two to complete. But researchers at the Lawrence Livermore National Laboratory aimed to speed up the process.
 
First they created an extremely fast thermal9 cycle, in which a sample experiences 45 degrees Celsius10 temperature changes per second. Then they searched for DNA amplification enzymes that could operate at that thermal cycling speed. And they found two that worked without any tweaking. The technique accomplishes a billion-fold amplification in well under three minutes. The work is in the journal Analyst11
 
The system could make it possible to identify food contamination virtually instantly. Or an infection before you even finish coughing.
 
Thanks for the minute. For Scientific American's 60-Second Science, I'm Cynthia Graber.

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1 DNA 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句:
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
2 amplification pLvyI     
n.扩大,发挥
参考例句:
  • The voice of despair may be weak and need amplification.绝望的呼声可能很微弱,需要扩大。
  • Some of them require further amplification.其中有些内容需进一步详细阐明。
3 diagnosis GvPxC     
n.诊断,诊断结果,调查分析,判断
参考例句:
  • His symptoms gave no obvious pointer to a possible diagnosis.他的症状无法作出明确的诊断。
  • The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做一次彻底的调查分析。
4 genetic PgIxp     
adj.遗传的,遗传学的
参考例句:
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
5 enzymes 7881ad8ce9c83424f7874e70266ed2d8     
n. 酶,酵素
参考例句:
  • It was said that washing powders containing enzymes remove stains more efficiently. 据说加酶洗衣粉除污更有效。
  • Among the enzymes which are particularly effective are pepsin, papain. 在酶当中特别有效的是胃朊酶、木瓜酶。
6 replicate PVAxN     
v.折叠,复制,模写;n.同样的样品;adj.转折的
参考例句:
  • The DNA of chromatin must replicate before cell division.染色质DNA在细胞分裂之前必须复制。
  • It is also easy to replicate,as the next subsection explains.就像下一个小节详细说明的那样,它还可以被轻易的复制。
7 analyzed 483f1acae53789fbee273a644fdcda80     
v.分析( analyze的过去式和过去分词 );分解;解释;对…进行心理分析
参考例句:
  • The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
  • The young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程,因为对他来说,爱是个不可分析的迷。 来自《简明英汉词典》
8 boon CRVyF     
n.恩赐,恩物,恩惠
参考例句:
  • A car is a real boon when you live in the country.在郊外居住,有辆汽车确实极为方便。
  • These machines have proved a real boon to disabled people.事实证明这些机器让残疾人受益匪浅。
9 thermal 8Guyc     
adj.热的,由热造成的;保暖的
参考例句:
  • They will build another thermal power station.他们要另外建一座热能发电站。
  • Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。
10 Celsius AXRzl     
adj.摄氏温度计的,摄氏的
参考例句:
  • The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
  • The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。
11 analyst gw7zn     
n.分析家,化验员;心理分析学家
参考例句:
  • What can you contribute to the position of a market analyst?你有什么技能可有助于市场分析员的职务?
  • The analyst is required to interpolate values between standards.分析人员需要在这些标准中插入一些值。
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