Temporal reflection and refraction in the presence of a zero-nonlinearity wavelength.

We put forth a theoretical model allowing for the analysis of short-pulse interactions at time boundaries in waveguides with arbitrary frequency-dependent nonlinear profiles, in particular those exhibiting a zero-nonlinearity wavelength. Moreover, this is performed within a photon-conserving framework, thus circumventing use of the nonlinear Schrödinger equation in such scenarios, as it may lead to unphysical outcomes. Results indicate that the waveguide zero-nonlinearity wavelength has a great influence on said interactions, specifically by defining spectral bands where either signal total reflection or signal transmission can occur. We believe these findings to be of relevance in the area of all-optical switching schemes based on the interaction of short pulses in nonlinear media.

Immunoexpression of Heat Shock Protein 70, Glypican 3, Glutamine Synthetase, and Beta-Catenin in Hepatocellular Carcinoma After Liver Transplantation: Association Between Positive Glypican 3 and Beta-Catenin With the Presence of Larger Nodules.

BACKGROUND: Hepatocellular carcinoma (HCC) is the 6th leading cause of cancer worldwide. Its recurrence ranges from 6% to 26%. In the literature, many factors are associated with higher risk of recurrence, without a clear definition of the best method that could predict this highly lethal event. OBJECTIVE: The aim of this study was to evaluate the immunoexpression of immunohistochemical markers: HSP70, glypican 3, glutamine synthetase, and beta-catenin, as well as studying their association with tumor characteristics and prognosis of patients undergoing liver transplantation for HCC. METHODS: We studied 90 patients who underwent liver transplantation from 1998 to 2012. Afterwards we evaluated factors related to survival, tumor recurrence, and the correlation of expression of the immunohistochemical markers. RESULTS: Immunohistochemical marker glutamine synthetase showed a positive trend toward better survival. HSP70-positive patients had a higher prevalence of histologic grade III. Patients with positive glypican 3 showed larger lesions and a higher number with AFP >200 ng/mL. Patients with positive beta-catenin showed larger nodules and more with histologic grade III. The association between beta-catenin and glypican 3 showed positive association with larger nodules. CONCLUSIONS: Most of the markers studied had a correlation with at least one of the variables studied, confirming our hypothesis that these markers can indeed assist in assessing the prognosis of patients undergoing liver transplantation for HCC.