The Editor in Chief has retracted this article after an investigation by the publisher found evidence of attempts to subvert the peer review process. Manat Tlebayev agrees to this retraction. Marina Baizharikova, Gulmira Tlebayeva, Zhenish Beksultanov and Rysty Tazhiyeva have not responded to correspondence from the Editor about this retraction. The online version of this article contains the full text of the retracted article as Supplementary Information.