http://airlinepilotchatter.blogspot.com/2013/03/what-is-that-thing-on-md80-nose-wheel.html
Debris deflector including for in case of a blown tyre, these contraption first came into being in a belly air intake fighters, adapted for the civilian, i really wonder if it was there in the Concorde that crashed on take off
(http://1.bp.blogspot.com/-UoZZ1TXY44s/UKdB1Vc1kAI/AAAAAAAAfQQ/zxZ_fpraC3k/s1600/Flanker15.jpg)