Abstract: A snoring sound detection apparatus includes one or plural microphones that receive sounds produced by a subject, and a controller including circuitry which converts the sounds produced by the subject to received signals, converts the received signals to sound intensity signals, measures the periodicity of sound intensity signal using one or plural sound intensity signals, evaluates the validity of the periodicity of sound intensity signal in terms of respiratory rate, and detects snoring sound using the sound intensity and the validity of the periodicity of sound intensity signal in terms of respiratory rate.

Abstract: A styrene derivative carrying N-acethylchito-oligosaccharide chains, a polystyrene derivative carrying N-acetylchito-oligosaccharide chains on the side chains as well as a method for preparing these compounds are herein disclosed. The method for preparing the styrene derivative comprises reacting N-acetylchito-oligosaccharide lactone with vinylbenzylamine or a derivative thereof while the method for preparing the polystyrene derivative comprises polymerizing the styrene derivative. These derivatives can be employed as biomedical materials, in particular as materials for cell culture.