生物燃料的提取来源非常多，但提取自餐厨垃圾的生物燃料被公认为最环保的几种之一。

Biofuels come from many sources and those derived from waste products are considered to be some of the most sustainable.

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Before that, diabetics had been treated with insulin that came from a different source, usually from pigs, so by harvesting and purifying insulin from pig pancreas.

在此之前 糖尿病患者,所用的胰岛素来自于不同的来源,通常是从猪身上提取的,是从猪的胰腺中提取并纯化而成的

耶鲁公开课 - 生物医学工程探索课程节选

That's a lot of the literature of stem cells that you'll read about, taking a particular source of stem cell and nurturing it in such a way that it gains potentials that it didn't have necessarily when it was in the body, or exploiting those potentials that it wouldn't necessarily express.

现在你可以找到很多,有关干细胞的文献中讲到,提取一种特定来源的干细胞,通过特定的培养方法之后,它们会获得在体内不能获得的潜能,或者开拓一些在体内不能得到表达的潜能

耶鲁公开课 - 生物医学工程探索课程节选