Isotope abundance profiles of two representative donor star models after the quenching of helium burning in DD I systems. Abundances are given in units of M_{isotope,shell}/M_shell over the mass coordinate. Panel (A): model sequence 11050045, with an initial WD mass of M_WD,i = 1.10 M_⊙, an initial donor star mass of M_d,i = 0.50 M_⊙, and an initial orbital period of P_init = 0.045 d. Panel (B): model sequence 11050075, with an initial WD mass of M_WD,i = 1.10 M_⊙, an initial donor star mass of M_d,i = 0.50 M_⊙, and an initial orbital period of P_init = 0.075 d.