螺杆泵虽然具有干吸能力,但是必须防止干转,以免擦伤工作表面。
Scientists are using a new stem cell technique allowing them to turn skin from patients into small pieces of brain.科学家使用一种新的干细胞技术,使他们可以将病人的皮肤转变为小块的大脑。
They are a special risk with stem cells precisely because such cells can turn into any other sort.对干细胞来说他们是一种特殊的风险,因为这种细胞能分化成任何其他种类。