They use their incredible sense of smell like a prehistoric homing device.

它们利用异常出色的嗅觉就像是史前追踪装置。

But one dinosaur in particular uses these scent marks as a homing device.

不过有一种恐龙却把这种味道当做定位装置。

They initially circulate in the recipient's peripheral bloodstream, but molecules on the stem cells, called chemokines, act as homing devices and quickly traffic them back to the marrow.

这些细胞先在受者的外周血液中循环，不过干细胞上被称为 “趋化因子” 的分子起到归巢作用，引导这些干细胞快速迁移回骨髓中。