On the Witt vectors of perfect rings in positive characteristic

The purpose of this article is to prove some results on the Witt vectors of perfect ${\mathbf{F}}_p$-algebras. Let $A$ be a perfect ${\mathbf{F}}_p$-algebra for a prime integer $p$ and assume that $A$ has the property $\mathbf{P}$. Then does the ring of Witt vectors of $A$ also have $\mathbf{P}$? A main theorem gives an affirmative answer for $\mathbf{P}=\mathrm{"}integrallyclosed\mathrm{"}$ under a very mild condition.