There are multiple errors throughout the Funding section. The complete Funding section should read: "This work was supported by National Natural Science Foundation of China (30972239 and 31130054, http://www.nsfc.gov.cn/Portal0/default152.htm), National Basic Research Program of China (973 Program, 2010CB126406, http://www.most.gov.cn/), National High-Tech R&D Program (863 Program, 2012AA10A402, 2012AA092204, 2012AA10A401 and 2012AA10A405, http://www.most.gov.cn/), Program for New Century Excellent Talents in University (NCET-10-0716, http://www.moe.edu.cn/), and Natural Science Foundation of Shandong Province (ZR2009DM019, http://www.sdnsf.gov.cn/portal/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."
Footnotes
Competing Interests: No competing interests declared.