Apparatus, methods system and devices for using alternated duty cycle control to achieve soft-switching for at least one switch of the two half-bridge switches. 2 to 1% sulphur, 1 to 25% of a reinforcing filler, 1 to 10% of emulsifiers, 2 to 8% of a resin which cross-links by reaction with polyisocyanates, and 0. Further the invention describes a drying cabinet for the drying of the damp material is treated in a treatment chamber of a drying cabinet in mechanically immobile condition which shows flaps to be switched between the circulation in the closed circulation and a treatment in the open circulation which make possible an introduction and exhausting from external air. In particular, the method provides specific biochemical factors to supplement cell culture medium during the redifferentiation process with the goal of regenerating tissue equivalents that resemble natural tissues both structurally and functionally.