Key legal question
Whether the appeal against the incidental order appointing the expert is admissible before the Federal Supreme Court.
Extracted holding
The appeal is inadmissible because only material or structural objections to the expert were raised, not formal grounds of recusal.
Extracted reasoning
Immediate federal review is available only when formal recusal grounds are decided. Objections attacking the usefulness, scope, or professional competence of the expert are materially directed and cannot be raised in this procedural avenue.