Biodegradable prostheses; surgical grafts and implants (made from artificial materials); biodegradable surgical grafts and implants (made from artificial materials); surgical grafts and implants (made from artificial materials) which are porous; surgical grafts and implants (made from artificial materials) in the form of foam, sheet or mesh; surgical mesh; surgical foams; surgical slings; surgical grafts and implants for use in the repair and treatment of hernia; hernia mesh; biodegradable porous devices for hernia repair and treatment; devices for use in hernioplasty; surgical grafts and implants for use in soft tissue reinforcement and augmentation; artificial skin; artificial skin for surgical purposes; artificial skin replacing membranes