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Heat generated by viscous energy dissipation and friction during high‐frequency fatigue testing can reduce the fatigue life of short fiber‐reinforced plastics. Herein, we proposed new method of determining an appropriate testing frequency, taking into consideration the temperature increase in SFRPs during fatigue testing. An experimental procedure was developed to obtain viscoelastic and thermal parameters in a theoretical model using dynamic mechanical analyses and fatigue tests with an infrared camera. Then, according to the stress levels under tension in fatigue tests, a critical frequency was calculated to allow a temperature increase within 10°C. Finally, experimental fatigue tests at low stress levels and high frequencies were performed, demonstrating the applicability of the current method to design fatigue tests that take into account stress levels at a given frequency and a limited temperature rise. [ABSTRACT FROM AUTHOR]

Design of materials with remote switchability of the movement of decorated nanostructures presenting cell‐adhesive Arg‐Gly‐Asp ligand can decipher dynamic cell‐material interactions in decorated ligand nanostructures. In this study, the decoration of ligand‐bearing gold nanoparticles (ligand‐AuNPs) on the magnetic nanoparticle (MNP) with varying ligand‐AuNP densities is demonstrated, which are flexibly coupled to substrate in various MNP densities to maintain constant macroscopic ligand density. Magnetic switching of upward ("Upper Mag") or downward ("Lower Mag") movement of varying ligand‐AuNPs is shown via stretching and compression of the elastic linker, respectively. High ligand‐AuNP densities promote macrophage adhesion‐regulated M2 polarization that inhibits M1 polarization. Remote switching of downward movement ("Lower Mag") of ligand‐AuNPs facilitates macrophage adhesion‐regulated M2 polarization, which is conversely suppressed by their upward movement ("Upper Mag"), both in vitro and in vivo. These findings are consistent with human primary macrophages. These results provide fundamental understanding into designing materials with decorated nanostructures in both high ligand‐AuNP density and downward movement of the ligand‐AuNPs toward the substrate to stimulate adhesion‐regulated M2 polarization of macrophages while suppressing pro‐inflammatory M1 polarization, thereby facilitating tissue‐healing responses. [ABSTRACT FROM AUTHOR]

Macrophage Polarization: Remote Switching of Elastic Movement of Decorated Ligand Nanostructures Controls the Adhesion-Regulated Polarization of Host Macrophages (Adv. Funct. Keywords: elastic ligand movement; macrophage adhesion; macrophage polarization; magnetic switching; nanoparticle decoration EN elastic ligand movement macrophage adhesion macrophage polarization magnetic switching nanoparticle decoration 1 1 1 05/26/21 20210521 NES 210521 In article number 2008698, Young Keun Kim, Heemin Kang, and co-workers report magnetic switching of the movement of decorated ligand-presenting nanostructures that regulates the adhesion-mediated polarization of macrophages in vivo. Elastic ligand movement, macrophage adhesion, macrophage polarization, magnetic switching, nanoparticle decoration. [Extracted from the article]