Deepika Kurup, a 14-year-old high school student from Nashua, New Hampshire won a $25,000 prise from the 3M Young Scientist Challenge for her solar powered water purification system based on TiO2, ZnO nanoparticles, 3M Glass bubbles, and cement. The TiO₂ and ZnO nanoparticles act as a photocatalyst to produce hydroxyl radicals that kills bacteria and the bubbles are used to reduce the weight of the purifier. Cement is a common local material in developing countries.