Abundance profiles for two of our SERIES II models with 2.1 M_⊙, Z = 0.02; f_OV = 0.0; η = 1.6 (top panel) and 2.4 M_⊙, Z = 0.02; f_OV = 0.0; η = 1.6 (bottom panel). On the left, the plots refer to chemical composition when log(ρ_c/g cm⁻³)≃9.0 (shortly before the Urca cooling phase). On the right, the plots refer to the final chemical composition of our models. In the case of the 2.4 M_⊙ model, off-center ignition of oxygen leads to the formation of a silicon core with amounts of residual oxygen distributed within the core.