  We have measured the half-life of the electron-capture (ec) decay of 97Ru in
a metallic environment, both at low temperature (19K), and also at room
temperature. We find the half-lives at both temperatures to be the same within
0.1%. This demonstrates that a recent claim that the ec decay half-life for 7Be
changes by $0.9% +/- 0.2% under similar circumstances certainly cannot be
generalized to other ec decays. Our results for the half-life of 97Ru,
2.8370(14)d at room temperature and 2.8382(14)d at 19K, are consistent with,
but much more precise than, previous room-temperature measurements. In
addition, we have also measured the half-lives of the beta-emitters 103Ru and
105Rh at both temperatures, and found them also to be unchanged.
