a b s t r a c tAn exact theory of interfacial debonding is developed for a layered composite system consisting of distinct linear elastic slabs separated by nonlinear, nonuniform decohesive interfaces. Loading of the top and bottom external surfaces is defined pointwise while loading of the side surfaces is prescribed in the form of resultants. The work is motivated by the desire to develop a general tool to analyze the detailed features of debonding along uniform and nonuniform straight interfaces in slab systems subject to general loading. The methodology allows for the investigation of both solitary defect as well as multiple defect interaction problems. Interfacial integral equations, governing the normal and tangential displacement jump components at an interface of a slab system are developed from the Fourier series solution for the single slab subject to arbitrary loading on its surfaces. Interfaces are characterized by distinct interface force-displacement jump relations with crack-like defects modeled by an interface strength which varies with interface coordinate. Infinitesimal strain equilibrium solutions, which account for rigid body translation and rotation, are sought by eigenfunction expansion of the solution of the governing interfacial integral equations. Applications of the theory to the bilayer problem with a solitary defect or a defect pair, in both peeling and mixed load configurations are presented.
Ostruthin, isolated from Paramignya trimera, was used as a scaffold to design its alkyl triphenylphosphonium derivatives. With the optimal reaction conditions in hand, five alkyl triphenylphosphonium ostruthin derivatives (1–5) were synthesized. Ostruthin and its derivatives were tested for cytotoxicity against human PANC‐1 pancreatic, Hela cervical, and HepG2 liver cancer cell lines. Ostruthin and its hexyl and heptyl triphenylphosphonium derivatives (4 and 5) showed strong preferential cytotoxicity against PANC‐1 cells with the PC50 values of 10.3 and 14.4 μM, respectively. In addition, compounds 4 and 5 also exhibited potent cytotoxicity towards HeLa cells with the IC50 values of 24.8 and 18.5 μM, respectively. The hexyl triphenylphosphonium group in 4 was found to slightly enhance cytotoxicity against HepG2 cells. Further, the morphological changes and the live‐cell imaging result suggested the anticancer potential against HeLa cells of the synthesized ostruthin derivative 5.
a b s t r a c tAn exact analysis of the mechanics of interface failure is presented for a trilayer composite system consisting of geometrically and materially distinct linear elastic layers separated by straight nonlinear, uniform and nonuniform decohesive interfaces. The technical significance of this system stems from its utility in representing two slabs joined together by a third adhesive layer whose thickness cannot be neglected. The formulation, based on exact infinitesimal strain elasticity solutions for rectangular domains, employs a methodology recently developed by the authors to investigate both solitary defect as well as multiple defect interaction problems in layered systems under arbitrary loading. Interfacial integral equations, governing the normal and tangential displacement jump components at the interfaces, are solved for the uniformly loaded trilayer system. Interfacial defects, taken in the form of interface perturbations and nonbonded portions of interface, are modeled by coordinate dependent interface strengths. They are examined in a variety of configurations chosen so as to shed light on the various interfacial failure mechanisms active in layered systems.
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