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.
X inactivation is a process by which one of the copies of the X chromosome present in the female mammals is inactivated. Explanation: The inactivated X chromosome condenses into a compact structure called as the he Barr body. Unlike the gene poor Y chromosome , the X chromosome contains over 1000 genes, that are essential for proper development and cell viability. Females carry two copies of X chromosomes , resulting in a double dose of X linked genes.