A method is described for separating, retrieving and concentrating platelets from whole blood relying on aggregation of the platelets followed by filtration. 01 to 2% by weight for preventing the formation of gas hydrates in aqueous phases which are in contact with a gaseous, liquid or solid organic phase. This presents a difficult situation for moving the stack onto a transport to a printer or other stations. The number of layers of the first periodic dielectric multilayer film is larger than that of the second periodic dielectric multilayer film. To overcome that, cascade transistor stages are used that have small increments in device sizes, preferably widths, between stages.