Response to comment by Cuk et al
  In a recent study of the optical conductivity of the Bi-2212 high temperature superconductor, Hwang, et al. have confirmed the mass-renormalization changes observed in ARPES but find that such changes are no longer observed in the highly overdoped regime. In a comment on this study, Cuk, et al. challenge this conclusion and present ARPES evidence for a kink in the superconducting state in the highly overdoped regime. We show, however that two doping dependent properties in the data of Cuk et al., the frequencies of the superconducting gap and the Van Hove singularity, suggest a Tc that is higher than the 58 K quoted, and that their sample is not as highly overdoped as claimed. As a result, these data can not refute the claim of Hwang et al. that the kink is absent in the highly overdoped region. 
T. Valla, P.D. Johnson, Genda Gu, J. Hwang, and T. Timusk