Financial & competing interests disclosure
This research was supported by grants from the project of Harbin Medical University (Daqing, China) Youth Science Foundation (Seed Fund, DQ201203), the Heilongjiang Provincial Natural Science Foundation (Heilongjiang Province, China; D201031), Heilongjiang Provincial Health Beureau Foundation (2009–265 and 2011–236). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
No writing assistance was utilized in the production of this manuscript.