In-medium nucleon-nucleon elastic cross-sections determined from the nucleon induced reaction cross-section data *Supported by Natural Science Foundation of Guangxi Province (2016GXNSFFA380001, 2017GXNSFGA198001), Foundation of Guangxi Innovative Team and Distinguished Scholar in Institutions of Higher Education, and National Natural Science Foundation of China (11365004, U1867212). (April 2019)