Development and validation of a risk model for noninvasive detection of cancer in oral potentially malignant disorders using DNA image cytometry

Objective:To elucidate whether DNA aneuploidy was an independent discriminator for carcinoma within oral potentially malignant disorders(OPMDs),and further establish and validate a risk model based on DNA aneuploidy for the detection of oral cancer.Methods:A total of 810 consecutive patients with OPMD were prospectively enrolled from March 2013 to December 2018,and divided into a training set(n=608)and a test set(n=202).Brushing and biopsy samples from each patient were processed by DNADNA image cytometry and histopathological examination,respectively.Results:DNA aneuploidy of an outside DNA index≥3.5 in OPMD was an independent marker strongly associated with malignant risk[adjusted odds ratio:13.04;95%confidence interval(CI):5.46-31.14].In the training and test sets,the area under the curve(AUC)was 0.87(95%CI:0.82-0.91)and 0.77(95%CI:0.57-0.97),respectively,for detecting carcinoma in OPMD patients.The independent risk factors of lateral/ventral tongue and non-homogenous type combined with a risk model built with a multivariate logistic regression revealed a more favorable diagnostic efficacy associated with the training set(AUC:0.93;95%CI:0.91-0.96)and test set(AUC:0.94;95%CI:0.90-0.98).The sensitivity and specificity of carcinoma detection within OPMD was improved to 100%and 88.1%,respectively.Conclusions:This large-scale diagnostic study established a risk model based on DNA aneuploidy that consisted of a noninvasive strategy with lateral/ventral tongue and non-homogenous features.The results showed favorable diagnostic efficacy for detecting carcinoma within OPMD,irrespective of the clinical and pathological diagnoses of OPMD.Multicenter validation and longitudinal studies are warranted to evaluate community practices and clinical applications.

Effect of corrosive media on galvanic corrosion of complicated tri-metallic couples of 2024 Al alloy/Q235 mild steel/304 stainless steel

Galvanic corrosion of tri-metallic couples is more complicated than that of bi-metallic couples. In this study, the effect of the pH of corrosive media on the galvanic corrosion of 2024 A1 alloy/Q235 mild steel/304 stainless steel tri-metallic couples was investigated using potentiodynamic polarization, scanning electron microscopy, scanning vibrating electrode technique and a multi-channel galvanic corrosion meter. The results show that 2024 always acts as the only anode in 3.5 wt% NaCl at pH 5.56,9.72 and 12.0, while both Q235 and 2024 act as anodes at pH 2.39 in the initial stage and then the role of Q235 changes at longer coupling time, which can be attributed to the effect of pH on the surface film of 2024. It is also found that the galvanic current density of a tri-metallic couple is the superposition of two bi-metallic couples when cathodic reactions are controlled by the diffusion of oxygen, otherwise it is smaller than that of the sum of two bi-metallic couples. The localized corrosion instead of uniform corrosion of anodic metal is accelerated by galvanic corrosion.