A visitor walks past a battlefield first-aid vehicle at the BioEco 2011 exhibition held in north China's Tianjin, June 26, 2011. The 4th International Conference for Bioeconomy (BioEco 2011), China's top bioeconomy forum, opened in Tianjin at the Meijiang Conference and Exhibition Center on Sunday. 222 Chinese and foreign companies have participated in the 3-day conference, showcasing over 1,000 biotechnological and biomedical products. [Xinhua/Wang Qingyan]