Specificity sensitivity and reproducibility

The RCA-based diagnostics exhibit an exceptional specificity for particular DNA/RNA sequences, as well as for marker molecules other than DNA/RNA, allowing the multiplex genotyping/detection of single-base mutations and specific antigens. Besides, RCA is an ultrasensitive method of detection: a variety of RCA formats permit essentially single-molecule counting of the DNA, RNA, or protein targets and some other analytes. Furthermore, RCA-based diagnostics are characterized by good repro-ducibility, with amplification errors being at a lower level compared to PCR. Consequently, such an exquisite sensitivity makes it possible to accurately and reliably quantify the gene copy number as well as to detect single-copy genes, discrete antigen-antibody complexes, and mRNA expression levels in individual cells.

Advantages and Limitations

RCA has several substantial advantages over other amplification techniques, which could be called ''the power of simplicity.''[17] Most importantly, RCA is an isothermal procedure and, therefore, has no need of special instrumentation to cycle the temperature, which is required with the widely used PCR-based diagnostics. This RCA feature significantly simplifies the automation and miniaturization of RCA-based diagnostics. In addition, RCA can be performed by a larger variety of DNA polymerases compared to PCR, which relies on only thermostable enzymes. Besides, RCA represents an inexpensive, more error-proof, and more sensitive (compared to PCR) analytical technology with a very wide dynamic range and higher multi-plexity to serve as a potent alternative to the thermocycling diagnostic methods.

In comparison with other isothermal methods of signal, probe, or target amplification, such as transcription-based amplification, strand-displacement amplification, use of branched (or dendrimeric) probes, invasive signal amplification, or loop-mediated amplification, the RCA-based assays are less complicated and in many cases do not require any substantial preoptimization of an experimental protocol, thus being readily used by a beginner. RCA is the most flexible and adaptable amplification methodology featuring merely few drawbacks. The shortcoming of supersensitive RCA assays is that they require certain caution to avoid possible contamination/false positives. In some cases, release of probes from the hybridized targets and removal of the nontargeted DNA strands by additional treatment with endo- and exonucleases are also necessary to reach the requisite sensitivity of detection.[10,19]

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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