Stem cells from pig fat helped grow bone grafts in a special chamber, shown here.
Sarindr Bhumiratana/Columbia Engineering
GUT REACTION Research on rats and mice suggests that gut bacteria start the cycle of obesity. The bacteria make a molecule called acetate that sends signals through the vagus nerve to stimulate hunger and fat storage.
Women exercise for fun and compete in sports, but when it comes to exercise science, men seem to matter most.