These are special chemicals, colorings or tastes that counterfeiters could not easily copy.

VOA: special.2010.03.01

another thing that you'd find if you looked inside the axon terminals of any of these pre-synaptic membranes, you'd find lots of vesicles or some membrane bound compartments that contain special chemicals called neurotransmitters.

如果你仔细观察,突触前膜的轴突末梢内部,你会发现很多小泡,即膜包被的结构,包含有称为神经递质的特殊化合物

耶鲁公开课 - 生物医学工程探索课程节选

Investigators sometimes use chemicals and special lighting to uncover fingerprints that cannot be seen with the eye alone.

VOA: special.2010.05.05