Changes with Age. In most cases, a person's normal respiratory rate will change with age; younger adults, children, and babies will typically have faster respiratory rates, because as people age, their breathing usually slows down.
Modic changes are pathological changes in the bones of the spine, the vertebrae. These changes are situated in both the body of the vertebrae and in the end plate of the neighboring disc.
Modafinil is a 1:1 racemic compound, whose enantiomers have different pharmacokinetics (e.g., the half-life of R-modafinil is approximately three times that of S-modafinil in adult humans). The enantiomers do not interconvert.