In materials science, there is an intrinsic conflict between high strength and high toughness, which can be resolved for different materials only through the use of innovative design principles. Advanced materials must be highly resistant to both deformation and fracture. We overcome this conflict in man-made polymer fibers and show multifibrillar polyacrylonitrile yarn with a toughness of 137 ± 21 joules per gram in combination with a tensile strength of 1236 ± 40 megapascals. The nearly perfect uniaxial orientation of the fibrils, annealing under tension in the presence of linking molecules, is essential for the yarn’s notable mechanical properties. This underlying principle can be used to create similar strong and tough fibers from other commodity polymers in the future and can be used in a variety of applications in areas such as biomedicine, satellite technology, textiles, aircrafts, and automobiles.

Though beam-based lattices have dominated mechanical metamaterials for the past two decades, low structural efficiency limits their performance to fractions of the Hashin-Shtrikman and Suquet upper bounds, i.e. the theoretical stiffness and strength limits of any isotropic cellular topology, respectively. While plate-based designs are predicted to reach the upper bounds, experimental verification has remained elusive due to significant manufacturing challenges. Here, we present a new class of nanolattices, constructed from closedcell plate-architectures. Carbon plate-nanolattices are fabricated via two-photon lithography and pyrolysis and shown to reach the Hashin-Shtrikman and Suquet upper bounds, via in situ mechanical compression, nano-computed tomography and micro-Raman spectroscopy. Demonstrating specific strengths surpassing those of bulk diamond and average performance improvements up to 639% over the best beam-nanolattices, this study provides detailed experimental evidence of plate architectures as a superior mechanical metamaterial topology.

Vaccines and therapies are not available for several diseases caused by viruses, thus viral infections result in morbidity and mortality of millions of people every year. Nanoparticles are considered to be potentially effective in inhibiting viral infections. However, critical issues related to their use include their toxicity and their mechanisms of antiviral action, which are not yet completely elucidated. To tackle these problems, we synthesized silica nanoparticles with distinct surface properties and evaluated their biocompatibility and antiviral efficacy. We show that nanoparticles exhibited no significant toxicity to mammalian cells, while declines up to 50% in the viral transduction ability of two distinct recombinant viruses were observed. We designed experiments to address the mechanism of antiviral action of our nanoparticles and found that their hydrophobic/hydrophilic characters play a crucial role. Our results reveal that the use of functionalized silica particles is a promising approach for controlling viral infection and offer promising strategies for viral control.

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Frozen transient imbibition states in arrays of straight cylindrical pores 400 nm in diameter were imaged by phase-contrast X-ray computed tomography with single-pore resolution. A semiautomatic algorithm yielding brightness profiles along all pores identified within the probed sample volume is described. Imbibition front positions are determined by descriptive statistics. A first approach involves the evaluation of frequency densities of single-pore imbibition lengths, and a second one involves the evaluation of the statistical brightness dispersion within the probed volume as a function of the distance from the pore mouths. We plotted average imbibition front positions against systematically varied powers of the imbibition time and determined the optimal exponent of the imbibition time by considering the correlation coefficients of the corresponding linear fits. Thus, slight deviations from the proportionality of the average imbibition front position to the square root of the imbibition time predicted by the Lucas–Washburn theory were found. A meaningful pre-exponential factor in the power law relating imbibition front position and imbibition time may only be determined after ambiguities regarding the exponent of the imbibition time are resolved. The dispersion of peaks representing the imbibition front in frequency densities of single-pore imbibition lengths and in brightness dispersion profiles plotted against the pore depth is suggested as measure of the imbibition front width. Phase-contrast X-ray computed tomography allows the evaluation of a large number of infiltrated submicron pores taking advantage of phase-contrast imaging; artifacts related to sample damage by tomography requiring physical ablation of sample material are avoided.

Nanometric ceria-decorated SBA-15 was prepared using a route involving the impregnation of SBA-15 pores by a solution of cerium(III) 2-ethylhexanoate, followed by its thermal decomposition. According to XRF analysis, the number of successive impregnation-decomposition cycles (IDC) allows control of the CeO 2 /SiO 2 ratio in the final material, and also the tailoring of the nanoparticle size of the fluorite CeO 2 nanoparticles supported in the SBA-15, as confirmed by XRD, Raman and UV-Vis spectroscopies. The mean pore size of the SBA-15 decreases with successive IDC, as observed by N 2 adsorption-desorption, suggesting that CeO 2 nanoparticles are located inside the SBA-15 mesopores, as confirmed by TEM and HRTEM analyses. The degree of oxygen storage capacity (OSC) was measured by the number of hydrogen uptake from the temperature programmed reduction (H 2 -TPR). It was found that the value of hydrogen uptake of SBA-15 submitted to one IDC corresponds to 3344 mmol of O 2 per gram of CeO 2 , whereas those of SBA-15 submitted to five and ten IDC were 1324 and 2769 mmol of O 2 per gram of CeO 2 , respectively.

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Bioactive glasses have been explored and used as implants and bone grafts for more than 40 years, in the form of granules, porous scaffolds, powders, and coatings. 1-3 These materials are capable to form an integrated bond with bone tissue through degradation and biomineralization at their surface, resulting in the formation of an apatite surface layer similar to that found in the bone mineral phase. 4 Bioactive glasses have been used in clinical applications since 1984, 5 but limited data are available about their chemomechanical (alterations in the mechanical properties due to reactions with a biological environment) and mechanochemical response (effect of mechanical strain on the dissolution rate of materials), which prevent the use of these materials to their full