Lead: 'Researchers must address the lack of knowledge about risks posed by nanotechnology in the health sector to provide appropriate input to policymakers, cautions a leading expert of the European Commission.' The article continues, 'More risk assessment studies are needed to understand what exactly defines toxicity due to nanoparticles, and what kind of regulations the sector needs, said Hermann Stamm, head of nanotechnology and molecular imaging at the Institute for Health and Consumer Protection in the European Commission's Joint Research Council.' T. V. Padma, SciDev.Net, 22 July 2008.