Cards that previously required you to take damage to keep them in play (Such as Ra Solar Flare or Tachyon Pushing the Limits) are now clarified to be destroyed if this damage is not taken. Cards officially reprinted are:
The text of these all these cards now reads "If [He/She/They] take no damage this way, destroy this card"
This Ruling is not limited to these cards, simply these were the ones that were reprinted. Any other card that requires its user to take damage to keep it in play is affected as well
(Known as Rule 15 because it was the 15'th point on a list of rules questions posted on the forums that were posed to Christopher during KantCon)