This article's nearly a year old, and yet it contains a relatively recent piece of progress, which I've only just noticed: http://www.sciencedaily.com/releases/2007/04/070406140937.htm The excitation state of the metastable nuclear isomer of Thorium-229 relative to ground has been accurately measured. If further research can trigger its transition back to ground, then it's hoped that this could lead to the nuclear battery. I'm sure we all remember that controversial announcement some years ago, by some guy claiming to have induced gamma-ray emission from the metastable isomer Hafnium-178, using an old dental x-ray machine. One of the national labs (Livermore? Los Alamos?) investigated and debunked the claim as false. So that seemed to have totally put prospects of harnessing isomers out in the cold. But this recent announcement that I posted above seems to indicate that research is still ongoing. I'd like to then know where the state of nuclear isomer research is, and whether it's considered to still have any promising prospects. Is anybody continuing with any research to try and achieve induced gamma emission from any metastable isomer?