Efficiency of replication

When a TaqMan assay is validated (the efficiency of replication is close to 1), the relative quantity of the target gene can be calculated using a ACt method using the relationship fold of induction=2 < " > = "" " >. 

The solvent used was 5 %v/v ethyl acetate in n-hexane at a flow rate of 0.5 ml/min. Each solute was dissolved in the mobile phase at a concentration appropriate to its extinction coefficient. Each determination was carried out in triplicate and, if any individual measurement differed by more than 3% from either or both replicates, then further replicate samples were injected. All peaks were symmetrical (i.e., the asymmetry ratio was less than 1.1). The efficiency of each solute peak was taken as four times the square of the ratio of the retention time in seconds to the peak width in seconds measured at 0.6065 of the peak height. The diffusivities obtained for 69 different solutes are included with other physical and chromatographic properties in table 1. The diffusivity values are included here as they can be useful in many theoretical studies and there is a dearth of such data available in the literature (particularly for the type of solutes and solvents commonly used in LC separations). 

The version 2.0 assay uses a different set of probes designed to hybridize to genotypes 1 to 6 with equal efficacy (Fig. 4). The new probe set not only enhanced the efficiency of binding to genotypic variants but also lowered the LOQ from 3.5 X 105 to 2 X 105 HCV RNA equivalents/ml (Detmer et al., 1996). The version 2.0 assay displayed almost a 600-fold dynamic range up to 1.2 X 108 RNA equivalents/ml. The LOQ was set at 2 X 105 to ensure a specificity of 95%. The assay was reproducible, with a mean CV of 14% for replicates of low-, middle-, and high-titer sera. Serial dilutions of quality level 1 RNA transcripts (Collins et al,... 

The precision of the method was tested by carrying out replicate analyses (10) on 150 ml aliquots of two seawater samples from the Irish Sea. Mean ( sd) arsenic concentrations of 2.63 0.05 and 2.49 0.05 pg/1 amounts of were found. The recovery of arsenic was checked by analysing 150 ml aliquots of arsenic-free seawater which had been spiked with known amounts of arsenic (V). The results of these experiments shows that there is a linear relationship between absorbance and arsenic concentration and that arsenic could be recovered from seawater with an average efficiency of 98.0% at levels of 1.3-6.6 pg/1. Analagous experiments in which arsenic (III) was used gave similar recoveries. 

The three sets of replicate results below were accumulated for the analysis of the same sample. Pool these data to obtain the most efficient estimate of the mean analyte content and the standard deviation. 

Tests were carried out to compare the efficiency of extraction results obtained using a manual weighing and sample preparation method, and the reagent adder and sample preparation unit. Extracts of four replicates of ten soils were prepared by each method and analysed for nitrate- plus nitrite-nitrogen by a diazotisation and coupling reaction with sulphanilic acid and N-(l-naphthyl)ethylenediamine and ammonium-nitrogen by an indophenol method. These methods are described fully by Greaves et al. [48]. 

Recovery measurements are one of the most difficult aspects in organic analysis. These measurements are often completed, with the minimum number of replicate determinations over a limited concentration range, to justify optimistically the use of a method. Experiments designed to obtain the efficiency of the analytical method often implicitly assume that this also includes the efficiency of extraction from the matrix [366]. 

Efficiency of full second-order polynomial models fit to data from central composite designs without replication. 

Designing an array is not a trivial task. In addition to the probes of interest, an array should include appropriate numbers of positive and negative control elements, such as housekeeping genes and controls that can be used to monitor the efficiency of important steps within the process. For example, you may wish to spike in internal standards that track recovery or labeling efficiency among different samples. It is also important to consider how you will print. How many replicates do you want Should these replicates be... 

Lead was extracted from nine replicates of NIST standard reference material 2709 (a contaminated soil) using various methods. The efficiencies of the various extraction methods were compared. 

The p53 protein is essential for the induction of apoptosis as a response to chromosomal damage (e.g., y-irradiation). It acts by blocking DNA replication of damaged cells. Cells deficient in p53 replicate in spite of the DNA damage to accumulate further mutations, thereby producing effects similar to overexpression of Bcl-2 to favor the accumulation of further mutations and reduce the efficiency of drugs for chemotherapy (E2). 

---