JanetB:  Jing Li, a scientist at NASA Ames, has been working for years on what will be the greatest phone accessory of all time. It's a small chip (about the size of a postage stamp) that houses 32 nanosensor bars. Each bar is composed of a different nano-structure material. Because each sensor bar is unique it can respond to different chemicals in different ways, enabling it to not only differentiate between them, but also to monitor their relative levels, in real time. 4 months ago