Before revision:  equation* G(  ) = a\mu_e V(\Omega_\bX)+ ad_w\mu_eA(M_\bX) + \sum_{i=1^H\nu_i \mu_i A(M_{\bX_i}), } a , \nu_i > 0, equation* where V(\Omega_\bX) is the volume of the domain \Omega_\bX enclosed by M_\bX, d_w is the diameter of a water molecule, and A(M_\bX) and A(M_{\bX_i) are the areas of M_\bX and M_{\bX_i}} \nablaxi  .
After revision:  equation* G( ) = a\mu_e V(\Omega_\bX)+ ad_w\mu_eA(M_\bX) + \sum_{i=1^H\nu_i \mu_i A(M_{\bX_i}), } a , \nu_i > 0, equation* where V(\Omega_\bX) is the volume of the domain \Omega_\bX enclosed by M_\bX, d_w is the diameter of a water molecule, and A(M_\bX) and A(M_{\bX_i) are the areas of M_\bX and M_{\bX_i}} -\nablaxi .