Abstract: An instrument is provided that can monitor nucleic acid sequence amplifications reactions, for example, PCR amplification of DNA and DNA fragments. The instrument includes a multi-notch filter disposed along one or both of an excitation beam path and an emission beam path. Methods are also provided for monitoring nucleic acid sequence amplifications using an instrument that includes a multi-notch filter disposed along a beam path.

Abstract: A method and apparatus for estimating drug effectiveness from a drug diffusion sample are provided. The drug diffusion sample includes a plate having a medium containing a test organism and a plurality of antibiotic disks positioned on the plate in a medium. An inhibition zone surrounds each of the antibiotic disks after a prescribed incubation period. The drug diffusion sample is illuminated, and an image of the drug diffusion sample is acquired with a video camera. The image is analyzed by determining the locations of the antibiotic disks, determining the average brightness and the brightness variance of the image in a region surrounding each of the antibiotic disks, and estimating the radius of the inhibition zone surrounding each of the antibiotic disks from the average brightness and the brightness variance. The radius of the inhibition zone is indicative of drug effectiveness.