  We present data analyses of the thermal conductivity and specific heat of
electron-doped Pr1.85Ce0.15CuO4-y. The zero-field thermal conductivity and
specific heat of this optimally electrondoped system can be only explained by a
nodeless gap symmetry. The magnetic-field dependence of the electronic specific
heat in the vortex state is in quantitative agreement with an s-wave theory.
Our quantitative data analyses provide bulk evidence for a nodeless gap
symmetry in optimally electron-doped cuprates.
