  This paper provides a method to get a noetherian equicharacteristic local UFD
with an isolated singularity from a given noetherian complete
equicharacteristic local ring, preserving certain properties. This is applied
to invesitgate the (non)vanishing of Ext modules. It is proved that there exist
a Gorenstein local UFD $A$ having an isolated singularity such that
$\operatorname{Ext}_A^{\gg0}(M,N)=0$ does not imply
$\operatorname{Ext}_A^{\gg0}(N,M)=0$, a Gorenstein local UFD $B$ having an
isolated singularity such that $\operatorname{Tor}_{>0}^B(M,N)=0$ does not
imply $\operatorname{depth}(M\otimes_B N)=\operatorname{depth}
M+\operatorname{depth} N-\operatorname{depth} B$, and a Cohen-Macaulay local
UFD $C$ having an isolated singularity such that
$\operatorname{Ext}_C^{>0}(M,C)=0$ does not imply the total reflexivity of $M$.
