Point Amplification Research Articles

The conditions of maximum for the superposition field of wave source points system in the Fresnel pattern

The description of the superposition field generated by a system of wave source points with coherent emission is discussed in this paper. The conditions for the problem parameters are identified in a general form, which enable satisfactory description of wave field within the framework of Fresnel and Fraunhofer approximations, respectively. In the presented approach a number of known results of the wave theory are reproduced, which are used for directional amplification. These results are summarized for the Fresnel diffraction case. The possibility to obtain a superposition field with point amplification is considered.

Quantification of E. coli DNA on a Flow-through Chemiluminescence Microarray Readout System after PCR Amplification

We report on a hybridization assay using DNA microarrays for the quantification of amplification products of the uidA gene of E. coli. Using the stopped-PCR strategy, the amplified target DNA was strongly dependent on the applied gene copies. The quantification was carried out by a flow-through chemiluminescence microarray readout system. The DNA microarrays were based on a poly(ethylene glycol)-modified glass substrate. The probes on the surface were 18 or 25 nucleotides long and the quantified PCR product was 60 nucleotides. The amplification was stopped after 25 cycles; at this point amplification was in the middle of the logarithmical phase, and the spread between different DNA starting concentrations reached the maximum. A conjugate of streptavidin and horseradish peroxidase (HRP) bound to the biotinylated strands on the microarray surface and catalyzed the reaction of luminol and hydrogen peroxide. The generated light emission was recorded by a sensitive charge-coupled device (CCD) camera. The detection limit for the gene uidA (beta-galactosidase) of E. coli was 1.1 x 10(5) copies/mL. This system allowed for a sensitive detection and quantification of E. coli in a concentration range from 10(6) to 10(9) copies/mL.