Spatio-temporal characterization of the underwater acoustic propagation : Group and phase velocities reconstruction

This study deals with the inverse problem in Ocean Acoustic Tomography by using the modal theory. We consider a range independent environment and a large vertical array receiver . We show in the case of the homogeneous medium First and in the general case then, that the beamforming patterns allow to reconstruct the link between the horizontal group velocities and the phase velocities of the propagated waves . Finally, we consider two applications : the direct sound speed reconstruction without a priori information and the depth estimation of transmitters or receivers.Cette étude traite du problème inverse en Tomographie Acoustique Océanique par la théorie des modes. Nous considérons des milieux de propagation invariants en distance. A partir des signaux reçus sur une antenne verticale, nous montrons d'abord dans le cas particulier du guide d'ondes homogène, puis dans le cas général, qu'un traitement classique par formation de voies permet de reconstituer le lien entre les vitesses de groupe horizontales et les vitesses de phase des ondes propagées dans le milieu. Nous terminons l'étude par deux applications : la reconstruction directe du profil de célérité sans information a priori et l'estimation de la profondeur relative des instruments

MicroRNA profiling of cisplatinresistant oral squamous cell carcinoma cell lines enriched withcancer-stem-cell-like and epithelial-mesenchymal transition-type features

Oral cancer is of major public health problem in India. Current investigation was aimed to identify the specific deregulated miRNAs which are responsible for development of resistance phenotype through regulating their resistance related target gene expression in oral squamous cell carcinoma (OSCC). Cisplatin-resistant OSCC cell lines were developed from their parental human OSCC cell lines and subsequently characterised. The resistant cells exhibited enhanced proliferative, clonogenic capacity with significant up-regulation of P-glycoprotein (ABCB1), c-Myc, survivin, β-catenin and a putative cancer-stem-like signature with increased expression of CD44, whereas the loss of E-cadherin signifies induced EMT phenotype. A comparative analysis of miRNA expression profiling in parental and cisplatin-resistant OSCC cell lines for a selected sets (deregulated miRNAs in head and neck cancer) revealed resistance specific signature. Moreover, we observed similar expression pattern for these resistance specific signature miRNAs in neoadjuvant chemotherapy treated and recurrent tumours compared to those with newly diagnosed primary tumours in patients with OSCC. All these results revealed that these miRNAs play an important role in the development of cisplatin-resistance mainly through modulating cancer stem-cell-like and EMT-type properties in OSCC