SSS 2011-10-07
时间：2019-01-08 作者：英语课 分类：Scientific American(十)月
英语课
PCR—the polymerase chain reaction—is a crucial tool. The DNA 1 amplification 2 technique is used in genome sequencing, forensics and the diagnosis 3 of various diseases.
To give researchers more genetic 4 material to work with, a PCR instrument repeatedly heats and cools an original biological sample. Which gives enzymes 5 a chance to replicate 6 the DNA millions of times so it can be more easily analyzed 7.
Such sequence amplification would be a boon 8 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 thermal 9 cycle, in which a sample experiences 45 degrees Celsius 10 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 Analyst 11.
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.
(缩)deoxyribonucleic acid 脱氧核糖核酸
- 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。
n.扩大，发挥
- 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。
n.诊断，诊断结果，调查分析，判断
- 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。
adj.遗传的，遗传学的
- 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。
n. 酶，酵素
- 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。
v.折叠，复制，模写；n.同样的样品；adj.转折的
- 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。
v.分析( analyze的过去式和过去分词 )；分解；解释；对…进行心理分析
- 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》
n.恩赐，恩物，恩惠
- 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。
adj.热的，由热造成的；保暖的
- 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。
adj.摄氏温度计的，摄氏的
- 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。