sent a mail to elsevier to get more information about this - Pierre
As Alf Eaton has pointed out if the challenge platform is MarkLogic (XML database used by lots of publishers, implied by Elsevier owning a licence and mentioning XQuery) using the NLM DTD your apps / ideas could be used by other scientific publishers too. Arguably in that case you'd deserve more than $2500 though. ;) - Euan
