So your family of four has been using a mobile sanitation toilet  for a week, and now you've got 35 liters of human waste that you desperately need to sterilize. Thanks to a new invention, all you need is some sunshine, a little water, and a dash of gold nanoparticles. These tiny metallic shells absorb so much energy from sunlight that they can transform water into steam at temperatures well below the liquid's usual boiling point of 100°C. In a new study, engineers show that they can use gold nanoparticles to build solar-powered sterilization systems  that never need to be plugged into an electrical grid. These autoclaves' efficiency and energy independence make them perfect for sterilizing everything from medical instruments in field hospitals to human waste in nonflushable toilets like the one pictured above, the researchers report online today in the Proceedings of the National Academy of Sciences. They hope that the invention will soon be used to prevent infections in the developing world and other places where high-tech sterilization systems can be hard to come by.
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