Retraction of: Promoting the Recovery of Injured Liver with Poly (3-Hydroxybutyrate-Co-3-Hydroxyvalerate-Co-3-Hydroxyhexanoate) Scaffolds Loaded with Umbilical Cord-Derived Mesenchymal Stem Cells by Li P, Zhang J, Liu J, Ma H, Liu J, Lie P, Wang Y, Liu G, Zeng H, Li Z, and Wei X. Tissue Eng. 2015;21(3-4):603–615. DOI: 10.1089/ten.tea.2013.0331