Not translatable strings

When I translated this module to Swedish there where two strings that couldn't be translated.
The strings are in conditional_fields.module on row 1167 and 1170. I tried to play around with it, but I were not able to make it translatable.

function theme_conditional_fields_manage_marker($controlling = NULL, $controlled = NULL) {
  $output = '';
  if ($controlling) {
    $output .= t('<div class="description">Controlled by <em>@controlling</em></div>', array('@controlling' => $controlling));
  }
  if ($controlled) {
    $output .= t('<div class="description">Controlling <em>@controlled</em></div>', array('@controlled' => $controlled));
  }
  return $output;
}