MRI of a knee. MRIs employ powerful magnets which produce a strong magnetic field that forces protons in the body to align with that field. When a radiofrequency current is then pulsed through the patient, the protons are stimulated, and spin out of equilibrium, straining against the pull of the magnetic field.
Noun. 1. aestivation - (zoology) cessation or slowing of activity during the summer; especially slowing of metabolism in some animals during a hot or dry period. estivation. zoological science, zoology-the branch of biology that studies animals.
GCIDE (0.00 / 0 votes) Rate this definition: deactivate (v. t.). To make inactive; to render ineffective; as, to deactivate a bomb; to deactivate a machine; to deactivate the alarm. The deactivation of a machine or device is usually a reversible process; switching off an electrical device may be referred to as deactivation. To render an enzyme or catalyst ineffective is more commonly referred to as to inactivate. deactivate (v. t.). To disband (a military unit, or other group); to discontinue (a group activity); as, to deactivate the regiment; to deactivate the investigation.