Chen ZS， Tong XM， Liu B， Cai DZ.
关键词骨髓基质细胞。

Dick often catches a few Zs on his way to work on the train.
迪克经常在坐火车上班的途中打个盹儿。

It could be argued that Edison was the first person to turn off the lights for the sole purpose of catching some midday Zs.
可以说爱迪生是第一位关灯来获得一些午间睡眠的人。