Every day, plants, algae, and bacteria generate more energy than all the world's power plants, using sunlight to split water into hydrogen and oxygen and then storing the energy in sugar molecules. Artificial photosynthes­is--the process of using solar power to split water through the creation of chemical bonds, as plants do--holds promise as a clean, cheap source of hydrogen to power fuel cells. But to make the process practical, researchers must find catalysts to decrease the amount of energy needed.

Several drugs treat cardiovascular disease by lowering levels of the lipoprotein complex LDL, commonly called "bad cholesterol" because it deposits the cholesterol in blood-vessel walls. But no existing therapies can directly increase HDL, or "good cholesterol," which carries the sticky molecule through the bloodstream and to the liver for excretion.