Protamine sulfate is a drug that reverses the anticoagulant effects of liver compounds such as heparin. Protamine is extracted from the sperm of salmon and other species of fish, and then made into a protamine sulfate injection which is a necessary d

发表于:2019-01-19 / 阅读(66) / 评论(0) 分类 世界各地新闻集锦

By counting back through these layers and measuring the amount of lead in each, he could work out global lead concentrations at any time for hundreds, or even thousands, of years. The notion became the foundation of ice core studies, on which much mo

发表于:2019-02-17 / 阅读(59) / 评论(0) 分类 万物简史

Lead is a neurotoxin. Get too much of it and you can irreparably damage the brain and central nervous system. Among the many symptoms associated with overexposure are blindness, insomnia, kidney failure, hearing loss, cancer, palsies, and convulsions

发表于:2019-02-17 / 阅读(53) / 评论(0) 分类 万物简史

If you were going to a restaurant and wanted a healthier option, 如果你去饭店,你想吃得健康一点, which would you choose, grilled or fried chicken? 你会选择哪种食品呢,烤鸡还是炸鸡? Now most people would answer grill

发表于:2019-02-21 / 阅读(68) / 评论(0) 分类 TED演讲教育篇

We keep pumping carbon dioxide into the atmosphere and the earth keeps warming. Climate scientists have predicted that the consequences of unchecked warming could result in everything from catastrophic flooding to larger and more deadly hurricanes. S

发表于:2019-02-23 / 阅读(50) / 评论(0) 分类 英语时差8,16

First off, I'll mention that at the bottom of the sea there exist veins of zinc, iron, silver, and gold whose mining would quite certainly be feasible. 首先,我对您说,海底有锌、铁、银、金等矿藏,开发并不是不可能的事。

发表于:2019-02-25 / 阅读(119) / 评论(0) 分类 《海底两万里》中英双语有声读物