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2607 2621 199 37-40 ; S ; [EN] This paper introduces a recovery-type error estimator yielding upper bounds of the error in energy norm for linear elastic fracture mechanics problems solved using the extended finite element method (XFEM) The paper can be considered as an extension and enhancement of a previous work in which the upper bounds of the error were developed in a FEM framework The upper bound property requires the recovered solution to be equilibrated and continuous The proposed technique consists of using a recovery technique, especially adapted to the XFEM framework that yields equilibrium at a local level (patch by patch) Then a postprocess based on the partition of unity concept is used to obtain continuity The result is a very accurate but only nearly-statically admissible recovered stress field, with small equilibrium defaults introduced by the postprocess Sharp upper bounds are obtained using a new methodology accounting for the equilibrium defaults, as demonstrated by the numerical tests This work has been carried out within the framework of the research projects DPI2007-66773-C02-01, DPI2007-66995-C03-02 and DPI2007-62395 of the Ministerio de Educacion y Ciencia (Spain). The financial support of the Generalitat Valenciana and the Universidad Politecnica de Valencia is also acknowledged. Ródenas, J.; Gonzalez-Estrada, O.; Díez, P.; Fuenmayor Fernández, F. (2010). Accurate recovery-based error upper bounds for the extended finite element framework. Computer Methods in Applied Mechanics and Engineering. 199(37-40):2607-2621. https://doi.org/10.1016/j.cma.2010.04.010

[EN] 'Communication' between abiotic nanoscale chemical systems is an almost-unexplored field with enormous potential. Here we show the design and preparation of a chemical communication system based on enzyme-powered Janus nanoparticles, which mimics an interactive model of communication. Cargo delivery from one nanoparticle is governed by the biunivocal communication with another nanoparticle, which involves two enzymatic processes and the interchange of chemical messengers. The conceptual idea of establishing communication between nanodevices opens the opportunity to develop complex nanoscale systems capable of sharing information and cooperating. ; A. L.-L. is grateful to 'La Caixa' Banking Foundation for his PhD fellowship. We wish to thank the Spanish Government (MINECO Projects MAT2015-64139-C4-1, CTQ2014-58989-P and CTQ2015-71936-REDT and AGL2015-70235-C2-2-R) and the Generalitat Valenciana (Project PROMETEOII/2014/047) for support. The Comunidad de Madrid (S2013/MIT-3029, Programme NANOAVANSENS) is also gratefully acknowledged. ; Llopis-Lorente, A.; Díez, P.; Sánchez, A.; Marcos Martínez, MD.; Sancenón Galarza, F.; Martínez-Ruiz, P.; Villalonga, R. (2017). Interactive models of communication at the nanoscale using nanoparticles that talk to one another. Nature Communications. 8:1-7. https://doi.org/10.1038/ncomms15511 ; S ; 1 ; 7 ; 8 ; Tseng, R., Huang, J., Ouyang, J., Kaner, R. & Yang, Y. Polyaniline nanofiber/gold nanoparticle nonvolatile memory. Nano Lett. 5, 1077–1080 (2005). ; Liu, R. & Sen, A. Autonomous nanomotor based on copper-platinum segmented nanobattery. J. Am. Chem. Soc. 133, 20064–20067 (2011). ; Valov, I. et al. Nanobatteries in redox-based resistive switches require extension of memristor theory. Nat. Commun. 4, 1771 (2013). ; Tarn, D. et al. Mesoporous silica nanoparticle nanocarriers: biofunctionality and biocompatibility. Acc. Chem. Res. 46, 792–801 (2013). ; Kline, T. & Paxton, W. Catalytic nanomotors: remote-controlled autonomous movement of striped metallic nanorods. ...