Acoustic tomography methods belong to the class of nondestructive inspection techniques and are used in engineering applications. One of the main issues for these methods is the direct arrival, which can be noisy or can be affected by scattering or other propagation effects. In this paper, we present the mathematical deduction and analysis of the so-called robust mean traveltime curves—the median, p-percentiles, inter-quartile range and minimum absolute deviation—for homogeneous isotropic or elliptical anisotropic media. Robust mean traveltime curves are a simple model used to describe the variation of the traveltime statistical descriptors for the different gathering subsets as a function of a gather index, and generalize the mean traveltime curves introduced in the past to the case of robust statistics. These curves admit analytical expression for zonal isotropic and elliptical anisotropic media explored via rectangular or irregular acquisition geometries, and thus, apply to 2D acoustic transmission tomography experiments conducted in relatively homogeneous blocks. The robust mean traveltime curves are more resistant to the presence of outliers, and thus they are preferred to infer background velocity models which can be taken into account in the resolution of the tomographic inverse problem. The property of robust descriptors to find blocky solutions in presence of velocity heterogeneities is also illustrated. Finally, we show the application of this methodology to a granitic medium (Febex Project, Nagra, Switzerland).

We have characterized a novel 21 amino acid-peptide derived from Antrum Mucosal Protein (AMP)-18 that mediates growth promotion of cultured normal epithelial cells and mitigates radiation-induced oral mucositis in animal models, while suppressing in vitro function of cancer cells. The objective of this study was to evaluate these dual potential therapeutic effects of AMP peptide in a clinically relevant animal model of head and neck cancer (HNC) by simultaneously assessing its effect on tumor growth and radiation-induced oral mucositis in an orthotopic model of HNC. Bioluminescent SCC-25 HNC cells were injected into the anterior tongue and tumors that formed were then subjected to focal radiation treatment. Tumor size was assessed using an in vivo imaging system, and the extent of oral mucositis was compared between animals treated with AMP peptide or vehicle (controls). Synergism between AMP peptide and radiation therapy was suggested by the finding that tumors in the AMP peptide/radiation therapy cohort demonstrated inhibited growth vs. radiation therapy-only treated tumors, while AMP peptide-treatment delayed the onset and reduced the severity of radiation therapy-induced oral mucositis. A differential effect on apoptosis appears to be one mechanism by which AMP-18 can stimulate growth and repair of injured mucosal epithelial cells while inhibiting proliferation of HNC cells. RNA microarray analysis identified pathways that are differentially targeted by AMP-18 in HNC vs. nontransformed cells. These observations confirm the notion that normal cells and tumor cells may respond differently to common biological stimuli, and that leveraging this finding in the case of AMP-18 may provide a clinically relevant opportunity.