Analogous peaks were evident in the simplex reactions, allowing for a peak-to-STR correlation (Figure 2).
When compared to the two simplex reactions, the duplex format did not shift Ct values and did in particular not compromise the sensitivity of the two assays.
In the presence of other bacteria (e.g. saprophytes), however, the limits may sometimes decrease tenfold compared to simplex reactions (Smid et al., 1995).
However, when 10 copies of DNA was used as template for the T304-40 test (18 out of 20 reactions were positive in the quadruplex PCR assay while all 20 simplex PCR reactions were positive. Differences were also observed in amplifications using five copies (5 μl templates) of DNA as template.
Additionally, simplex TnT reactions were performed for four of the individuals to confirm the results of the multiplex amplification.
All loci were amplified in an outer 10-plex PCR followed by an inner 10-plex PCR for genotyping with PrASE and also 10 inner simplex PCR reactions for genotyping with Pyrosequencing.
A simpler version involves just one projection step and stabilizes the reaction simplex.
If there are negative components, the nearest vector in the reaction simplex is found by solving a quadratic optimization problem; this vector is shown to better approximate the true solution.
On the other hand, the method uses the insight that tangent bifurcation points are precisely the loci where the equilibrium manifold and the reaction simplex become tangent.
The corresponding equilibrium curves for a given set of parameters are depicted in Figure 3 where it can be observed how the equilibrium manifold is tangent to the direction of the reaction simplex in two different points of the state space.
