Just a quick one here — been pointed to the existence of a “self-sterilizing” keyboard (e.g., Brier Dudleys Blog | FDA OKs Vioguards germ-killing keyboard | Seattle Times Newspaper.) from a company called Vioguard. Clearly keyboards could be a “breeding” ground for nasty microbes so cleaning keyboards, especially those used in hospitals, seems like a good idea. This keyboard works by retracting into a drawer and then exposing the keyboard to UV irradiation. UV is a good way to kill microbes (and other organisms) so this is not a totally crazy idea. One major issue I have with this is that I see nothing in their literature or anywhere about the possibility of selecting for UV resistant organisms, which is known to occur when organisms are exposed to cycles of UV irradiation. So while this keyboard may work well when you first set it up, it may become less efficient over time. Not saying it is a good or a bad idea per se – but any time one exposes microbes to a stress (e.g., antibiotics) you have to worry about resistance emerging …
I would think the other major issue would be the shadow effect. There must be crevices on the keyboard that are sheltered from the light. Not only could this provide a place for microbes to hide, but it means there would also be a gradient of UV light between full UV (kills microbes) and no UV (they hide out). Along that gradient there will be places where the mutation rate caused by the UV will be just optimal for accelerating evolution.