Systems and methods are disclosed for detecting an interruption of connection between a blood treatment apparatus and a patient blood circulation. The barrier may be formed from a polymer material that is sealed to define an interior void. A feature is that a gate electrode is formed of conductive films of plural layers, and by using the selection ratio of those at the time of etching, the concentration of an impurity region formed in an active layer is adjusted. A method of using only two sensors to control the state of an object in graphic arts programs. The pigment particles generated, according to the present invention, are stable in solvent under an electric field and can improve the performance of an electrophoretic display.