SSS 2011-11-04
时间：2019-01-08 作者：英语课 分类：Scientific American(十一)月
英语课
This is Scientific American's 60-Second Science. I'm Sophie Bushwick. Got a minute?
The early bird gets the worm—and may avoid skin cancer. Because a new mouse study suggests that, for humans, tanning in the mornings may be less likely to permanently 1 damage DNA 2 and cause skin cancer.
A mouse's levels of the DNA-repairing protein XPA are different from ours—they peak in the morning and bottom out in the evening. Researchers exposed mice to UV radiation when their XPA was at its minimum level, around 4 a.m., and others to the same rays around 4 p.m., when XPA levels peaked.
Mice who tanned while low on the repair protein developed skin cancer faster and five times more frequently than their evening-tanning counterparts. The study is in the Proceedings 3 of the National Academy of Sciences.
Unlike mice, humans are not nocturnal, so their XPA levels rise and fall at different times. In people, XPA is at prime DNA-repairing levels in the morning, which thus looks the safest time for UV exposure. So if you want to avoid skin cancer, probably go to the tanning salon 4 early—or better yet, don't go at all.
Thanks for the minute. For Scientific American's 60-Second Science, I'm Sophie Bushwick.
adv.永恒地，永久地，固定不变地
- The accident left him permanently scarred.那次事故给他留下了永久的伤疤。
- The ship is now permanently moored on the Thames in London.该船现在永久地停泊在伦敦泰晤士河边。
(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.进程，过程，议程；诉讼(程序)；公报
- He was released on bail pending committal proceedings. 他交保获释正在候审。
- to initiate legal proceedings against sb 对某人提起诉讼