Synthetic platelets(血小板)injected into a trauma victim at the time of injury can hasten clotting and help stem(流れを止める)internal bleeding. Researchers have developed a synthetic blood-clotting agent made from polymers that bind to the body's activated platelets, reducing bleeding. In rat studies, the synthetic platelets cut bleeding time in half. Blood loss is a major cause of death following traumatic injury incidents, so stopping bleeding quickly is vital to saving lives. If approved for use in humans, the treatment could be particularly useful on the battlefield, where soldiers often suffer traumatic injuries.