Fiber-based structures are highly desirable for wearable electronics that are expected to be light-weight, long-lasting, flexible, and conformable. Many fibrous structures have been manufactured by well-established lost-effective textile processing technologies, normally at ambient conditions. The advancement of nanotechnology has made it feasible to build electronic devices directly on the surface or inside of single fibers, which have typical thickness of several to tens microns. However, imparting electronic functions to porous, highly deformable and three-dimensional fiber assemblies and maintaining them during wear represent great challenges from both views of fundamental understanding and practical implementation. This article attempts to critically review the current state-of-arts with respect to materials, fabrication techniques, and structural design of devices as well as applications of the fiber-based wearable electronic products. In addition, this review elaborates the performance requirements of the fiber-based wearable electronic products, especially regarding the correlation among materials, fiber/textile structures and electronic as well as mechanical functionalities of fiber-based electronic devices. Finally, discussions will be presented regarding to limitations of current materials, fabrication techniques, devices concerning manufacturability and performance as well as scientific understanding that must be improved prior to their wide adoption.

Wing polyphenism is an evolutionarily successful feature found in a wide range of insects. Long-winged morphs can fly, which allows them to escape adverse habitats and track changing resources, whereas short-winged morphs are flightless, but usually possess higher fecundity than the winged morphs. Studies on aphids, crickets and planthoppers have revealed that alternative wing morphs develop in response to various environmental cues, and that the response to these cues may be mediated by developmental hormones, although research in this area has yielded equivocal and conflicting results about exactly which hormones are involved. As it stands, the molecular mechanism underlying wing morph determination in insects has remained elusive. Here we show that two insulin receptors in the migratory brown planthopper Nilaparvata lugens, InR1 and InR2, have opposing roles in controlling long wing versus short wing development by regulating the activity of the forkhead transcription factor Foxo. InR1, acting via the phosphatidylinositol-3-OH kinase (PI(3)K)-protein kinase B (Akt) signalling cascade, leads to the long-winged morph if active and the short-winged morph if inactive. InR2, by contrast, functions as a negative regulator of the InR1-PI(3)K-Akt pathway: suppression of InR2 results in development of the long-winged morph. The brain-secreted ligand Ilp3 triggers development of long-winged morphs. Our findings provide the first evidence of a molecular basis for the regulation of wing polyphenism in insects, and they are also the first demonstration--to our knowledge--of binary control over alternative developmental outcomes, and thus deepen our understanding of the development and evolution of phenotypic plasticity.

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Interconnected porous MnO nanoflakes on nickel foam were prepared by a reduction of hydrothermal synthesized MnO 2 precursor in hydrogen. The architectures were applied to lithium ion batteries as electrodes. Compared with the as-synthesized MnO 2 anode, porous MnO nanoflakes showed superior cycling stability and rate performance. A high reversible capacity of 568.7 mA h g À1 was obtained at a current density of 246 mA g À1 for the second discharge. It retained a capacity of 708.4 mA h g À1 at the 200th charge-discharge cycle after cycling with various current densities up to 2460 mA g À1 and delivered a capacity of 376.4 mA h g À1 at a current density as high as 2460 mA g À1 , indicating that the architecture of the porous MnO nanoflakes grown on Ni foam is a promising electrode for lithium ion batteries.

Three-dimensional network structured a-Fe 2 O 3 was prepared by a facile chemical corrosion of a stainless steel plate followed by thermal oxidation. When the architecture was directly used as an electrode for lithium ion batteries (LIBs), a high reversible capacity of 858.2 mA h g À1 was obtained at a current density of 200 mA g À1 for the 2nd discharge. Especially, it retained a capacity of 1105.6 mA h g À1 at the 100th discharge-charge cycle. The mechanism behind the capacity increase with cycling has been investigated based on the capacity changes in different voltage regions. After cycling with various current densities, it can deliver a capacity of 520.0 mA h g À1 at a current density as high as 5000 mA g À1 , indicating that the electrode prepared by such a simple route can be a promising candidate for high-power LIBs.

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High-T c superconductors confined to two dimension exhibit novel physical phenomena, such as superconductor-insulator transition. In the Bi 2 Sr 2 CaCu 2 O 8 þ x (Bi2212) model system, despite extensive studies, the intrinsic superconducting properties at the thinness limit have been difficult to determine. Here, we report a method to fabricate high quality single-crystal Bi2212 films down to half-unit-cell thickness in the form of graphene/Bi2212 van der Waals heterostructure, in which sharp superconducting transitions are observed. The heterostructure also exhibits a nonlinear current-voltage characteristic due to the Dirac nature of the graphene band structure. More interestingly, although the critical temperature remains essentially the same with reduced thickness of Bi2212, the slope of the normal state T-linear resistivity varies by a factor of 4-5, and the sheet resistance increases by three orders of magnitude, indicating a surprising decoupling of the normal state resistance and superconductivity. The developed technique is versatile, applicable to investigate other two-dimensional (2D) superconducting materials.