The Karolinska Institutet, the signed authors, and the editors retract the article cited above. An investigation performed by the Swedish Research Council has concluded that the results as published cannot be considered reliable.

The following authors agreed to the retraction: Elzafir Elsheikh, Mehmet Uzunel, and Grzegorz Nowak.

The following authors did not agree to the retraction: Zhong He, Jan Holgersson, and Suchitra Sumitran-Holgersson.

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