A system and method for removing nitrogen and producing a high pressure methane product stream from natural gas feed streams is disclosed. Using the same light source to illuminate both the display board and the buttons eliminates the need for separate button lighting, simplifying the assembly and reducing the assembly’s operating temperature. The protection circuit has a detector for detecting the voltage across the resistor and an evaluation circuit which is designed in such a manner that it evaluates an output signal from the detector after the first switch has been switched on and provides a fault signal at an output when the voltage across the resistor is greater than the threshold voltage. When a movable plug is used, the plug is movable between a closed position separating rocket chamber into subchambers isolating the propellant grains from each other and an open position allowing the flow of combustion gas between the two subchambers to achieve additional axial thrust. Isoflavones display many useful biochemical effects. One or more gullets extend radially inward from the perimeter of the core.