Authors’ contributions
Ai Gao and Shasha Guan designed and performed the study, analyzed the data and wrote the manuscript. Yinjuan Sun, Lingling Wang and Guo Li helped with recording patient diaries. Fanlu Meng, Xia Liu and Liyan Gu assisted with data interpretation and manuscript preparation. Linlin Zhang and Diansheng Zhong conceived the study, designed the experiments, interpreted the results, wrote the paper and oversaw the research project. All authors reviewed the manuscript.