Flow cytometers must be calibrated prior to fluorescence intensity measurements because of inherent instrument variability. To correct for this variability, a standard particle (fixed chicken red blood cells, or CRBCs) must be analyzed on the instrument prior to each experiment and photomultiplier tube (PMT) voltages adjusted accordingly to place the CRBC fluorescence emission peaks into predetermined target channels. - [Read Calibration of Becton Dickinson Flow Cytometers for Relative Fluorescence Intensity Measurements]
Protocol for pulsed-field gel electrophoresis via contour-clamped homogeneous electric field gels. In CHEF gels, the electric field is generated from multiple electrodes, arranged in a square of hexagonal contour around the horizontal gel and clamped to predetermined potentials. Using a combination of low field strengths, low concentrations of aragose, long switching intervals, and extended periods of electrophoresis, DNAs up to 5000 kb can be resolved. - [Read Pulsed-field Gel Electrophoresis via Contour-clamped Homogeneous Electric Field Gels Protocol]