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By virtue of reversible energy dissipation and good ionic conductivity, metal ions have been extensively introduced to construct hydrogels. However, the traditional soaking method to prepare metal ions coordination hydrogels (MI‐HG) faces the challenge of diffusion and combination of metal ions, leading to weak mechanical properties. Inspired by the leather mineral tanning mechanism, a strategy that controls the accessibility of hydrogels by pickling and basifying processes thus significantly improving the strength and toughness of MI‐HG is proposed. To achieve this, polyvinyl alcohol/poly(acrylamide‐co‐acrylic acid) (PVA/PAM‐co‐PAA) hydrogels‐bearing ligands similar to those of leather collagen are fabricated. Zr4+, Cr3+, Al3+, and Fe3+ commonly used for mineral tanning are chosen as the metal source. The results demonstrate that the mechanical properties of the products (MI‐HGTanning) are significantly promoted, especially for Cr3+ and Zr4+. For example, the tensile strength of Zr‐HGTanning and toughness of Cr‐HGTanning reach 7.79 ± 0.41 Mpa and 28.01 ± 3.1 MJ m−3, approximately three and seven times that of their soaking samples. From macro to micro characterization and by theoretical simulation, the mineral tanning mechanism of metal ions first permeating and then effectively combining with carboxylates, thus improving the mechanical performance of MI‐HGTanning is deciphered, the products of which are promised applications in flexible force sensors. [ABSTRACT FROM AUTHOR]

We find very low frequency earthquakes (VLFEs) in Cascadia under northern Washington during 2011 episodic tremor and slip event. VLFEs are rich in low-frequency energy (20-50s) and depleted in higher frequencies (higher than 1Hz) compared to local earthquakes. Based on a grid search centroid moment tensor inversion, we find that VLFEs are located near the plate interface in the zone where tremor and slow slip are observed. In addition, they migrate along strike with tremor activity. Their moment tensor solutions show double-couple sources with shallow thrust mechanisms, consistent with shear slip at the plate interface. Their magnitude ranges between Mw 3.3 and 3.7. Seismic moment released by a single VLFE is comparable to the total cumulative moment released by tremor activity during an entire episodic tremor and slip event. The VLFEs contribute more seismic moment to this episodic tremor and slip event than cumulative tremor activity and indicate a higher seismic efficiency of slow earthquakes in Cascadia than previously thought. Spatiotemporal correlation of VLFE and tremor activity suggests that they are the results of the same physical processes governing slow earthquakes. Key Points Systematic search reveals very low frequency earthquakes (VLFEs) in Cascadia VLFEs are associated with tremor and migrate with it in space and time VLFEs cluster near the peak slip during episodic tremor and slip event

Inorganic biomaterials are used in various orthopedic and dental implants. Nevertheless, they cause clinical issues such as loosening of implants and patient morbidity. Therefore, inspired by mussel adhesive proteins, we aimed to design an adhesive and dimer-forming highly active bone morphogenetic protein-2 (BMP-2) using bioorthogonal chemistry, in which recombinant DNA technology was combined with enzymatic modifications, to achieve long-term osseointegration with titanium. The prepared BMP-2 exhibited substantially higher binding activity than wild-type BMP-2, while the adhered BMP-2 was more active than soluble BMP-2. Therefore, the adhesive BMP-2 was immobilized onto titanium wires and screws and implanted into rat bones, and long-term osteogenesis was evaluated. Adhesive BMP-2 promoted the mechanical binding of titanium to bones, enabling efficient bone regeneration and effective stabilization of implants. Thus, such adhesive biosignaling proteins can be used in regenerative medicine. [ABSTRACT FROM AUTHOR]

Advanced nucleic acid amplification techniques require separating test samples into numerous units (digitalization), which enables higher sensitivity and accuracy than traditional methods. Reagent partition tools are commercially available, but are usually complex and expensive, hindering mass adoption. Herein, the fabrication of a large‐scale micro‐through‐hole array on glass substrates for an advanced digital nucleic acid amplification technique (NAAT) is demonstrated. To meet the requirement of hole quantities (over tens of thousands) for valid nucleic acid statistics, ultrafast Bessel pulses with continuous translation of the glass substrate are applied. A single‐shot Bessel pulse can lead to a single hole, and 100 holes can be produced per second (scalable to thousands per second). Experiments using the fabricated chips show that the performance meets the NAAT requirements. This work provides a highly efficient and low‐cost scheme for reagent partitioning that promotes the wide accessibility of advanced digital NAATs as well as a variety of other applications. [ABSTRACT FROM AUTHOR]