Oil shale gas has served as a substitute for natural gas, but, producing oil shale gas as a natural-gas substitute remained economically infeasible.
Thus, when autologous grafts are not available, biological substitutes remain the best options.
Key challenges associated with the outcomes of vascular grafting (for example, to fully vascularize engineered tissues and promptly regenerate blood vessel substitutes) remain unsolved.
A multicentric randomized, 3-year prospective study was conducted to determine for how long Biodentine, a new biocompatible dentine substitute, can remain as a posterior restoration.
Small caliber vessels substitutes still remain an unmet clinical need; few autologous substitutes are available, while synthetic grafts show insufficient patency in the long term.
As for the rest of us, there is no substitute for remaining alert, because whether the target is a plane, train or hotel lobby, we need to watch out for one another.
Attempts to substitute the remaining alkyl group at elevated temperatures have been shown to be possible, however, the end product is a zinc cluster.
The south coast club have broken their transfer record to sign Guido Carrillo from Monaco for £19.2m – the striker made his debut as a late substitute – and they remain hopeful of signing the Spartak Moscow forward Quincy Promes before the window closes.
Gilberto subsequently commented that while he was not happy being a substitute, he would remain professional and fight for his place at the club.
Sunderland's supporters, at odds with Poyet following the midweek home defeat by QPR, were to their immense credit, at one with their manager in regards to Bradford's display, applauding their former players Stead and Billy Knott when they were substituted, then remaining to acknowledge the efforts of the rest after the final whistle.
