A speaker cone is provided that contains a base portion, and the base portion has a front end and a rear end. The non-excitatory electric field affects the activity of the smooth muscle in a manner that controls a level of a chemical in the blood stream. If the sensing zone of the Mach Zehnder interferometer is disturbed, modified counter-propagating signals are produced, and the time difference between receipt of those signals is used to determine the location of the event. The new closed, modular and scalable cell-culturing chamber can be thus perfused and used to culture cells with high levels of cell function in organ assist systems, for production of cells, for production of cell-derived products, such as proteins or viruses, or for systems to treat biological liquids to remove toxins, such as ammonia, add cell-synthesized products, or both. The warning lights are connected to at least one controller that provides various patterns of warning lights involving at least one color. An LED or an LED array of a base color with a beam path oriented in the direction of the display unit is arranged on the optical axis of the illumination module.