Rocky S Tuan1, Timothy O'Brien2. 1. Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, 15219, PA, USA. rst13@pitt.edu. 2. REMEDI, CURAM, National University of Ireland Galway, Galway, Ireland. timothy.obrien@nuigalway.ie.
After publication of this article [1] it was brought to the Editors’ attention that it was previously published by the OMICS Journal of Stem Cell Research & Therapy. The authors report that they requested retraction before submission to Stem Cell Research & Therapy but did not receive a response. The OMICS Journal of Stem Cell Research & Therapy has now removed the article from its website without a formal retraction notice. Given that this article is no longer a duplicate publication, we have decided not to retract this version. We are issuing this Expression of Concern to alert readers should they find versions of the OMICS Journal of Stem Cell Research & Therapy article before it was removed from that journal’s website. We apologize to all affected parties.