Bản ghi email: Retraction notice to “Suppression of pro-inflammatory and proliferative pathways by diferuloylmethane (curcumin) and its analogues dibenzoylmethane, dibenzoylpropane, and dibenzylideneacetone: Role of Michael acceptors and Michael donors” [Biochem. Pharmacol. 82 (2011) 1901–1909]