In a tire 1, a central land portion row 20C and intermediate land portion rows 20M are formed by center-side main grooves 10C. The catalytically active unit of the present invention is particularly useful for removing noxiant, odorant and poisonous entities of any kind, in particular from air andor gas streams, and for protecting against chemical poisonous entities, in particular warfare agents, for example in NBC protective materials. Each fluid circuit includes a variable orifice which allows selection between a firm rebound with a soft compression, a soft rebound with a soft compression, and a soft rebound with a firm compression. The morphology and thickness of the calcium phosphate film can be controlled by the duration of the spark and the distance between the affected surface and the counterelectrode utilized.