still susceptible to fatigue fracture during multiple-cycle mechanical loads, exhibiting fatigue threshold (i.e., the minimal fracture energy required for crack propagation under cyclic loads) below 100 J m −2 . [5][6][7] Therefore, the long-term reliability has substantially hampered the in practical utility of hydrogels and hydrogel-based devices, and remains a key challenge in these fields.On the contrary, biological tissues, such as skeletal muscles, tendon and cartilage, are well known for not only their superior strength, modulus, toughness, but also long-term robustness. [8][9][10] For example, skeletal muscles can sustain a high stress (i.e., 1 MPa) over millions cycles per year without fracture, exhibiting fatigue thresholds (i.e., the minimal fracture energy required for crack propagation under cyclic loads) over 1000 J m −2 , despite their high water content (≈80%). [8,11] Such unrivalled fatigue-resistance originates from their hierarchically-arranged collagen fibrillar micro/nanostructures. [10] Despite bioinspired construction of structural materials has been promising for the design of fatigue-resistant hydrogels, [12][13][14][15][16][17] how to produce hydrogel materials with unprecedented fatigue-resistance in a universal and viable manner still remains an open issue. More recently, fatigue-resistant hydrogels have been fabricated by engineering the crystalline domains, [12][13][14] fibril structures, [15,16] or mesoscale phase separation. [17] Ice-templated freeze-casting strategy has been utilized as a powerful technology to impart Nature builds biological materials from limited ingredients, however, with unparalleled mechanical performances compared to artificial materials, by harnessing inherent structures across multi-length-scales. In contrast, synthetic material design overwhelmingly focuses on developing new compounds, and fails to reproduce the mechanical properties of natural counterparts, such as fatigue resistance. Here, a simple yet general strategy to engineer conventional hydrogels with a more than 100-fold increase in fatigue thresholds is reported. This strategy is proven to be universally applicable to various species of hydrogel materials, including polysaccharides (i.e., alginate, cellulose), proteins (i.e., gelatin), synthetic polymers (i.e., poly(vinyl alcohol)s), as well as corresponding polymer composites. These fatigueresistant hydrogels exhibit a record-high fatigue threshold over most synthetic soft materials, making them low-cost, high-performance, and durable alternatives to soft materials used in those circumstances including robotics, artificial muscles, etc.

The rational construction of efficient bifunctional oxygen electrocatalysts is of immense significance yet challenging for rechargeable metal-air batteries. Herein, this work reports a metal-organic framework derived 2D nitrogendoped carbon nanotubes/graphene hybrid as the efficient bifunctional oxygen electrocatalyst for rechargeable zinc-air batteries. The as-obtained hybrid exhibits excellent catalytic activity and durability for the oxygen electrochemical reactions due to the synergistic effect by the hierarchical structure and heteroatom doping. The assembled rechargeable zinc-air battery achieves a high power density of 253 mW cm −2 and specific capacity of 801 mAh g Zn −1 with excellent cycle stability of over 3000 h at 5 mA cm −2 .Moreover, the flexible solid-state rechargeable zinc-air batteries assembled by this hybrid oxygen electrocatalyst exhibits a high discharge power density of 223 mW cm −2 , which can power 45 light-emitting diodes and charge a cellphone. This work provides valuable insights in designing efficient bifunctional oxygen electrocatalysts for long-life metal-air batteries and related energy conversion technologies.

Transmissible gastroenteritis virus (TGEV) has been reported to induce apoptosis in swine testis (ST) cells. However, the mechanisms underlying TGEV-induced apoptosis are still unclear. In this study we observed that TGEV infection induced apoptosis in porcine kidney (PK-15) cells in a time- and dose-dependent manner. TGEV infection up-regulated FasL, activated FasL-mediated apoptotic pathway, leading to activation of caspase-8 and cleavage of Bid. In addition, TGEV infection down-regulated Bcl-2, up-regulated Bax expression, promoted translocation of Bax to mitochondria, activated mitochondria-mediated apoptotic pathway, which in turn caused the release of cytochrome c and the activation of caspase-9. Both extrinsic and intrinsic pathways activated downstream effector caspase-3, followed by the cleavage of PARP, resulting in cell apoptosis. Moreover, TGEV infection did not induce significant DNA fragmentation in ammonium chloride (NH(4)Cl) pretreated PK-15 cells or cells infected with UV-inactivated TGEV. In turn, block of caspases activation also did not affect TGEV replication. Taken together, this study demonstrates that TGEV-induced apoptosis is dependent on viral replication in PK-15 cells and occurs through activation of FasL- and mitochondria-mediated apoptotic pathways.

The formation of CdS nanotetrahedrons, pencil-shaped nanorods, tetrapods, prickly spheres, and high aspect-ratio hexagonal nanoprisms has been, respectively, achieved by adjusting the ratio of two solvents ethylenediamine and ethylene glycol under the solvothermal condition. None of the surfactants or other templates was needed in the process. The reaction time and temperature can be used as the additional means to control the size and morphology. By closely inspecting the growing process of the tetrapod structure and the crystallographic analysis of the products, we proposed that the lattice space match and the location match of ions at the interface of the zinc blende core and the wurtzite arms are two important structural factors to guide this furcate growth. Also, the anisotropic adsorption ability of ethylenediamine at the different surfaces of wurtzite CdS crystals results in the 1D growth of the arms. The possible growing mechanisms of CdS with other shapes were also discussed.

Recent electronics technology development has provided unprecedented opportunities for enabling implantable bioelectronics for long-term disease monitoring and treatment. Current electronics-tissue interfaces are characterized by weak physical interactions, suffering from potential interfacial failure or dislocation during long-term application. On the other hand, some new technologies can be used to achieve robust electronics-tissue interfaces; however, such technologies are limited by potential risks and the discomfort associated with postdetachment of the bioelectronics. Here, a hydrogel-based electronicstissue interface based on the exploitation of dynamic interactions (such as boronate-diol complexation) that features an interfacial toughness over 400 J m −2 is presented. Moreover, these hydrogel adhesion layers are also triggerdetachable by dissociating the dynamic complexes (i.e., addition of glucose). These hydrogel-based bioelectronic interfaces enable the in vivo recording of physiological signals (i.e., electromyograph, blood pressure, or pulse rates). Upon mild triggering, these bioelectronics can be easily detached without causing any damage, trauma, or discomfort to the skin, tissues, and organs. This kind of trigger-detachable hydrogel adhesives offer general applicability in bioelectronic interfaces, exhibiting promising utility in monitoring, modulating, and treating diseases where temporary monitoring of physiologic signals, interfacial robustness, and postremoval of bioelectronics are required.