Cell to Cell Communication WHO International Programme on Chemical Safety The Seventeen Plane Groups van Oystaeyen The Seventeen Plane Groups The subject of Partial Differential Equations (PDEs) which first emerged in the 18th century holds an exciting and special position in the applications relating to the mathematical modelling of physical phenomena The present volume represents an effort to provide the reader with an actualized view of the mechanisms of cell communication and of the physiologi­ cal and pathological implications of junctional and nonjunctional communica­ tion Our knowledge of the physiological modulators of junctional permeability is still scanty