The absence of DNA in RNA samples was systematically checked by running a control PCR reaction made in absence of reverse transcription.
The accuracy and reliability of the devised method was systematically checked by using a large amount of data taken from the literature and generated by testing steel welded details both under uniaxial and multiaxial nominal loading.
The quality of extracted DNA and the lack of PCR inhibitors were systematically checked by targeting a housekeeping gene, human β-actin (14 ).
DNA and RNA concentration and quality were systematically checked by UV absorption at 260 and 280 nm using a NanoDrop ND1000 spectrophotometer (Nanodrop technologies, Wilmington, DE, USA).
The integrity of RNA was systematically checked by use of the lab-on-chip technology in an Agilent Bioanalyzer 2100 with the RNA6000 Nano Assay (Agilent Technologies, Palo Alto, CA).
Finally, the accuracy and reliability of the devised method was systematically checked by means of several experimental results taken from the literature and generated by testing a variety of welded geometries subjected to uniaxial as well as to multiaxial fatigue loading.
The accuracy and reliability of our fatigue life estimation technique was systematically checked by reanalysing approximately 500 experimental results taken from the literature and generated by testing welded samples having not only different geometries but also different absolute dimensions.
The accuracy of the proposed approach was systematically checked by means of several experimental data taken from the literature and generated by testing different metallic materials under both in-phase and out-of-phase biaxial fatigue loading.
The specificity of the hybridization signal was systematically checked by hybridizing sense probes on parallel sections and anti-sense probes on uninfected genital tissues.
The specificity of the amplification was systematically checked by melting curve analysis at the end of each run of real time RT-PCR.
