They move from regions of high concentration to regions of low concentration by this natural flow down a concentration gradient.

从高浓度区域,向低浓度区域流动,顺浓度梯度流动

耶鲁公开课 - 生物医学工程探索课程节选

Movement down a concentration gradient occurs fairly rapidly over short distances like a micron or so, like the size of a bacterium.

顺浓度梯度扩散在一微米左右的短距离内,相当迅速,一微米相当于一个细菌的大小

耶鲁公开课 - 生物医学工程探索课程节选

Because we have, as you've hopefully realized, made a concerted effort over the past several years to really reach out to students on this campus who might not otherwise have considered this as a field of exploration, just a one semester course, or even ultimately a concentration or minor.

你们也认识到了，因为我们，在过去几年中作出了共同的努力,来影响这个校园的学生们,但是某些学生可能认为这并不是一个探索性的领域,而只是学期中的一个课程而已，或者只是一门主修或选修课程。

哈佛公开课 - 计算机科学课程节选

We can never just have it there before us or, as I say, if we can--if we can--it's a very, very difficult act of concentration.

我们永远不能只面对着它，或者，要我来说，如果我们可以的话，那将需要高度集中注意力，这是很难的。

耶鲁公开课 - 文学理论导论课程节选

And that was when I switched my concentration from computer science to philosophy and psychology with a single question: ? how can I become happier?

于是我将研究方向,从计算机科学转向了哲学及心理系,目标只有一个：,如何变得更快乐？

哈佛公开课 - 幸福课课程节选

In the case of a ligand-receptor, a chemical signal in the form of a concentration of ligand gets converted into a biochemical signal.

在配体-受体系统中,配体浓度这种化学信号,转化为生化信号

耶鲁公开课 - 生物医学工程探索课程节选

Now, we're not thinking about total antibody concentration because you already have a lot of antibodies circulating within your blood and in your fluids.

现在,我们先不考虑抗体总浓度,因为你的体内已存在许多抗体,在血液以及体液中循环

耶鲁公开课 - 生物医学工程探索课程节选