Volcanic activity broke the large island into pieces that came to the surface of the sea over time.

VOA: special.2009.12.16

In this case, a receptor tyrosine kinase is a receptor molecule that binds a ligand at its surface outside the cell and initiates this enzyme activity - this kinase activity - and causes phosphorylation of another molecule.

在这个例子中,酪氨酸激酶受体可以,在细胞表面区域与配体结合,从而激发出,激酶的活性,使其能够磷酸化另一类分子

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She found out about the volcanic activity that has shaped the surface of Mars.

VOA: special.2010.07.28

This will be useful because the location and activity of receptor proteins on surface membranes can be a matter of life and death for a cell or a virus.

ECONOMIST: Microscopy

The researchers specifically rejected any assumption that the 1995 increase of hurricane activity was related to any global surface temperature increases over the past century that might be ascribed to anthropogenic (man-made) greenhouse gases.

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Magnetic activity on the stellar surface could also be caused by accretion of material onto it.

MSN: Newborn star's 'heartbeat' seen by X-ray telescopes