SUMMARYThe paper addresses some fundamental aspects about the use of standard constitutive equations to model strong discontinuities (cracks, shear bands, slip lines, etc.) in solid mechanics analyzes. The strong discontinuity analysis is introduced as a basic tool to derive a general framework, in which different families of constitutive equations can be considered, that allows to extract some outstanding aspects of the intended analysis. In particular, a link between continuum and discrete approaches to the strain localization phenomena is obtained. Applications to standard continuum damage and elastoplastic constitutive equations are presented. Relevant aspects to be considered in the numerical simulation of the problem (tackled in Part 2 of the work) are also presented.
Purpose: Tumor somatic mutation analysis is part of the standard management of metastatic lung cancer. However, physicians often have to deal with small biopsies and consequently with challenging mutation testing. Circulating free DNA (cfDNA) is a promising tool for accessing the tumor genome as a liquid biopsy. Here, we evaluated next-generation sequencing (NGS) on cfDNA samples obtained from a consecutive series of patients for the screening of a range of clinically relevant mutations.Experimental Design: A total of 107 plasma samples were collected from the BioCAST/IFCT-1002 lung cancer study (never-smokers cohort). Matched tumor DNA (tDNA) was obtained for 68 cases. Multiplex PCR-based assays were designed to target specific coding regions in EGFR, KRAS, BRAF, ERBB2, and PI3KCA genes, and amplicon sequencing was performed at deep coverage on the cfDNA/tDNA pairs using the NGS IonTorrent Personal Genome Machine Platform.Results: CfDNA concentration in plasma was significantly associated with both stage and number of metastatic sites. In tDNA, 50 mutations (36 EGFR, 5 ERBB2, 4 KRAS, 3 BRAF, and 2 PIK3CA) were identified, of which 26 were detected in cfDNA. Sensitivity of the test was 58% (95% confidence interval, 43%-71%) and the estimated specificity was 87% (62%-96%).Conclusion: These data demonstrate the feasibility and potential utility of mutation screening in cfDNA using IonTorrent NGS for the detection of a range of tumor biomarkers in patients with metastatic lung cancer. Clin Cancer Res; 20(17); 4613-24. Ó2014 AACR.
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