Clinical, Histological and Prognosis Correlations in Diagnosis and Treatment of Gastric Cancer.

Purpose The study authors have proposed to highlight the main epidemiologic and prognostic aspects of digestive malignancies in the Dolj county population, justifying the need for permanent and detailed estimate of this phenomenon. Methods The authors of the study have proposed to outline a descriptive epidemiological panel, characteristic for the population groups at risk of developing gastric cancers and establishing clinical factors (tumor location, disease stage, type of surgery) and histological factors (histopathological type, degree of tumor differentiation) with prognostic significance having as landmark, survival rate at 5 years or disease-free survival of 5 years. Results The study was conducted on a sample of 458 patients with gastric tumors endoscopically detected, histologically confirmed and treated between 2000-2010. The epidemiological study allowed us to outline the descriptive epidemiological panel characteristic for the group of patients at risk of developing gastric cancer. Analysis of correlation between clinical parameters and histopathological parameters reached statistical threshold in multivariate statistical analysis of the localization of tumor, disease stage and histological type (p <0.0001) and the degree of differentiation of gastric carcinomas (p <0.005). Multivariate statistical analysis has detected statistically significant differences in terms of survival rate at 5 years (p> 0.001) and free interval of disease at 5 years (p> 0.001), depending on the location of the tumor, correlated with other clinical factors (disease stage, type of surgery) and histological factors (histopathological type, tumor differentiation grade), which allowed us to outline clinical, histological and prognostic groups. Conclusions Defining the clinical, histological and prognostic groups, allows an accurate assessment of patient prognosis from the time of randomization and initiation of treatment, type of surgery in advanced loco-regional, reconverted to operability, after neoadjuvant polychemotherapy being dictated by the location of the tumor (1/3 superior vs. 1 / 3 medium vs. 1/3 lower stomach).

On the generation of nonlinear travelling waves in confined geometries using electric fields.

We investigate electrostatically induced interfacial instabilities and subsequent generation of nonlinear coherent structures in immiscible, viscous, dielectric multi-layer stratified flows confined in small-scale channels. Vertical electric fields are imposed across the channel to produce interfacial instabilities that would normally be absent in such flows. In situations when the imposed vertical fields are constant, interfacial instabilities emerge due to the presence of electrostatic forces, and we follow the nonlinear dynamics via direct numerical simulations. We also propose and illustrate a novel pumping mechanism in microfluidic devices that does not use moving parts. This is achieved by first inducing interfacial instabilities using constant background electric fields to obtain fully nonlinear deformations. The second step involves the manipulation of the imposed voltage on the lower electrode (channel wall) to produce a spatio-temporally varying voltage there, in the form of a travelling wave with pre-determined properties. Such travelling wave dielectrophoresis methods are shown to generate intricate fluid-surface-structure interactions that can be of practical value since they produce net mass flux along the channel and thus are candidates for microfluidic pumps without moving parts. We show via extensive direct numerical simulations that this pumping phenomenon is a result of an externally induced nonlinear travelling wave that forms at the fluid-fluid interface and study the characteristics of the generated velocity field inside the channel.