Rhinovirus stimulation of interleukin-6 in vivo and in vitro

A grinding mill system including a grinding mill, a motor driven feeder for supplying material to the feed end of the mill, a classifier, means for carrying mill production in a gaseous stream, such as air to the inlet of the classifier for the separation of oversize material, a duct for returning oversize material to the feed inlet of the mill and means associated with the duct, including a rotary position transmitter responsive to variation in the rate of flow of oversize or reject material through said duct and means for controlling the feeder motor in response to actuation of the rotary position transmitter and variations in the rate of flow of reject material from the classifier to the feed inlet of the mill. The control system may include means such as a microphone responsive to variations in the sound of the mill.