Methods for the preparation of N-arylated oxazolidinone compounds via a copper catalyzed cross coupling reaction are disclosed. For this, a variable capacitor circuit includes a plurality of variable capacitors being connected in parallel with each other and having different capacitances with respect to an input control voltage, wherein the sum of the variable capacitances of the plurality of variable capacitors at a same voltage level of the control voltage varied within the whole control voltage range has linearity. An end address is determined by applying a stored parameter, related to the parameter type, to a pre-recorded or transmitted algorithm. A set of scores is updated based on the presence of any of the features in the string while searching for the features. The hardware acceleration and resource sharing advantages provided by the FPGA can be utilized more often by the application. In some embodiments, the guide system includes a pair of rotatable support arms having first pivot ends and second ends and an expandable pipe guide connecting the second ends.