Transformation of pancreatic nonfunctioning neuroendocrine tumor into metastatic insulinoma: A rare case report

Key Clinical Message Pancreatic neuroendocrine tumors can be classified as functional or nonfunctional based on hormone secretion. Management of each entity is different, with nonfunctional tumors being treated with traditional chemotherapy while functional tumors respond well to antihormonal therapy and immunologic agents. The conversion of one nonfunctional tumor into a functional tumor is an exceedingly rare event that complicates the overall management of these patients. In this report, we present the case of a 73‐year‐old woman who developed the conversion from a nonfunctional into a functional tumor and discuss the management options considered

Individual Role of the Physicochemical Characteristics of Nanopatterns on Tribological Surfaces

Nanoscale patterns have dimensions that are comparable to the length scales affected by intermolecular and surface forces. In this study, we systematically investigated the individual roles of curvature, surface energy, lateral stiffness, material, and pattern density in the adhesion and friction of nanopatterns. We fabricated cylindrical and mushroom-shaped polymer pattern geometries containing flat- and round-topped morphologies using capillary force lithography and nanodrawing techniques. We showed that the curvature, surface energy, and density of the patterns predominantly influenced the adhesive interactions, whereas lateral stiffness dominated friction by controlling the geometrical interaction between the indenter and pillar during sliding. Interestingly, in contrast to previous studies, cylindrical and mushroom-shaped pillars showed similar adhesion characteristics but very different frictional properties. Using fracture mechanics analysis, we showed that this phenomenon is due to a larger ratio of the mushroom flange thickness (<i>t</i>) to the radius of the pillar stem (ρ), and we proposed a design criterion for mushroom patterns to exhibit a geckolike effect. The most important result of our work is the discovery of a linear master curve in the graph of adhesion versus friction for pillars with similar lateral stiffness values that is independent of curvature, material, surface energy, and pattern density. These results will aid in the identification of simple pattern parameters that can be scaled to tune adhesion and friction and will help broaden the understanding of nanoscale topographical interactions