The distributed network of receptors, neurons, and synapses in the somatosensory system efficiently processes complex tactile information. We used flexible organic electronics to mimic the functions ...of a sensory nerve. Our artificial afferent nerve collects pressure information (1 to 80 kilopascals) from clusters of pressure sensors, converts the pressure information into action potentials (0 to 100 hertz) by using ring oscillators, and integrates the action potentials from multiple ring oscillators with a synaptic transistor. Biomimetic hierarchical structures can detect movement of an object, combine simultaneous pressure inputs, and distinguish braille characters. Furthermore, we connected our artificial afferent nerve to motor nerves to construct a hybrid bioelectronic reflex arc to actuate muscles. Our system has potential applications in neurorobotics and neuroprosthetics.
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BFBNIB, NMLJ, NUK, ODKLJ, PNG, SAZU, UL, UM, UPUK
Laser‐induced graphene (LIG) is a newly emerging 3D porous material produced when irradiating a laser beam on certain carbon materials. LIG exhibits high porosity, excellent electrical conductivity, ...and good mechanical flexibility. Predesigned LIG patterns can be directly fabricated on diverse carbon materials with controllable microstructure, surface property, electrical conductivity, chemical composition, and heteroatom doping. This selective, low‐cost, chemical‐free, and maskless patterning technology minimizes the usage of raw materials, diminishes the environmental impact, and enables a wide range of applications ranging from academia to industry. In this review, the recent developments in 3D porous LIG are comprehensively summarized. The mechanism of LIG formation is first introduced with a focus on laser‐material interactions and material transformations during laser irradiation. The effects of laser types, fabrication parameters, and lasing environment on LIG structures and properties are thoroughly discussed. The potentials of LIG for advanced applications including biosensors, physical sensors, supercapacitors, batteries, triboelectric nanogenerators, and so on are also highlighted. Finally, current challenges and future prospects of LIG research are discussed.
Laser‐induced graphene (LIG) is an emerging porous material produced when irradiating a laser beam on certain carbon materials. This in‐depth review highlights the recent advances in LIG research, including the mechanism of LIG formation, typical lasers in LIG fabrication, effects of lasing parameters on LIG structures and properties, and applications of LIG in flexible electronics.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Fast, simple, cost‐efficient, eco‐friendly, and design‐flexible patterning of high‐quality graphene from abundant natural resources is of immense interest for the mass production of next‐generation ...graphene‐based green electronics. Most electronic components have been manufactured by repetitive photolithography processes involving a large number of masks, photoresists, and toxic etchants; resulting in slow, complex, expensive, less‐flexible, and often corrosive electronics manufacturing processes to date. Here, a one‐step formation and patterning of highly conductive graphene on natural woods and leaves by programmable irradiation of ultrafast high‐photon‐energy laser pulses in ambient air is presented. Direct photoconversion of woods and leaves into graphene is realized at a low temperature by intense ultrafast light pulses with controlled fluences. Green graphene electronic components of electrical interconnects, flexible temperature sensors, and energy‐storing pseudocapacitors are fabricated from woods and leaves. This direct graphene synthesis is a breakthrough toward biocompatible, biodegradable, and eco‐friendlily manufactured green electronics for the sustainable earth.
Ultrashort femtosecond laser pulses enable one‐step patterning of highly conductive graphene electronics on natural woods and leaves in ambient air. Arbitrary graphene patterns can be directly formed on thin, flexible, and heat‐sensitive dried leaves without any pre‐treatment by femtosecond laser pulses. This direct graphene synthesis could be a breakthrough toward biocompatible, biodegradable, and eco‐friendlily‐manufactured green electronics for a sustainable earth.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The development of green flexible micro‐supercapacitors (MSCs) is one of the biggest challenges in future wearable electronics. Flexible MSCs are mainly produced from non‐biodegradable synthetic ...polymers, resulting in massive electronic waste. Moreover, complex multi‐step fabrication increases their production cost. Here, the direct fabrication of highly conductive, intrinsically flexible, and green microelectrodes from naturally fallen leaves in ambient air using femtosecond laser pulses without any additional materials is reported. Hierarchically porous graphene is patterned on different types of leaves via a facile, mask‐less, scalable, and one‐step laser writing. Leaves consist of biominerals, which decompose into inorganic crystals that serve as nucleation sites for the growth of 3D mesoporous few‐layer graphene. The femtosecond laser‐induced graphene (FsLIG) microelectrodes formed on leaves have lower sheet resistance (23.3 Ω sq−1) than their synthetic polymer counterparts and exhibit an outstanding areal capacitance (34.68 mF cm−2 at 5 mV s−1) and capacitance retention (≈99% after 50 000 charge/discharge cycles). The FsLIG MSCs on a single leaf could easily power a light‐emitting diode or a table clock and could be applied in wearable electronics, smart houses, and Internet of Things.
Arbitrary graphene microelectrodes are directly patterned on fallen leaves in ambient air by ultraviolet ultrafast laser. The graphene microelectrodes on leaves exhibit superior electrical conductivity compared with their synthetic polymer counterparts. Due to unique hierarchical porous structures, flexible graphene micro‐supercapacitors on leaves show excellent performance that can be utilized for green wearable electronics.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
An electronic (e‐) skin is expected to experience significant wear and tear over time. Therefore, self‐healing stretchable materials that are simultaneously soft and with high fracture energy, that ...is high tolerance of damage or small cracks without propagating, are essential requirements for the realization of robust e‐skin. However, previously reported elastomers and especially self‐healing polymers are mostly viscoelastic and lack high mechanical toughness. Here, a new class of polymeric material crosslinked through rationally designed multistrength hydrogen bonding interactions is reported. The resultant supramolecular network in polymer film realizes exceptional mechanical properties such as notch‐insensitive high stretchability (1200%), high toughness of 12 000 J m−2, and autonomous self‐healing even in artificial sweat. The tough self‐healing materials enable the wafer‐scale fabrication of robust and stretchable self‐healing e‐skin devices, which will provide new directions for future soft robotics and skin prosthetics.
An extremely tough and water‐insensitive self‐healing elastomer crosslinked through multistrength hydrogen bonding interactions is described. The resultant crosslinking network in polymer film realizes exceptional mechanical properties such as notch‐insensitive high stretchability (1200%), a high toughness of 12 000 J m−2, and autonomous self‐healing even in artificial sweat. The tough self‐healing materials enable the wafer‐scale fabrication of robust and stretchable self‐healing e‐skin devices.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The large size concrete structures are continuously placed with time delay due to practical reasons. The bond strength between old concrete and new concrete is related with a performance of concrete ...structures. In order to investigate bond strength of slant shear specimens, the specimens (100 × 100 × 300 mm) were fabricated and tested. Two fractions of setting retarder (0% and 1%), surface roughness (none, brushed, and chipping), and curing hours (8, 16, 24, and 72 hours) were considered as variables. Failure modes, compressive strength, and displacement were measured to evaluate the bond strength of specimens. As a result, chipping treatment, which is commonly applied to increase the bond strength between old and new concrete, did not show significant increase of bond strength. The addition of retarder shows that the increased bond strength compared with the chipping treatment. The addition of the retarder in concrete shows sufficient bond strength after the previous placing of 16 hours. Furthermore, the retarder-added specimens with additional brushing treatment of concrete surfaces showed increase of bond strength more than the specimens without brushing. From the test results, it is confirmed that the addition of the retarder can be a new method to increase the bond strength of the concrete surface in continuous placement of concrete.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Global demand for energy conversion and storage technologies such as fuel cells, water electrolyzers, batteries, and supercapacitors is increasing, yet their commercial and environmental viability ...are critically dependent on the performance of their electrode materials and catalysts, which are the indispensable components that drive these systems. Among various materials, layered double hydroxides (LDHs) are considered promising candidates for catalysts and electrodes for electrochemical energy conversion and storage systems. Their diverse range of chemical properties make them highly versatile platforms for developing hybrid nanostructures, including flexible two-dimensional LDH nanostructures with various di-/tri-valent metals. Hybrid LDHs also exhibit unique structural attributes, including 3D hierarchical porous features and heterointerfaces, as well as optimized electrical conductivity and stability, which are crucial to achieving highly efficient multifunctional nanomaterials for electrochemical energy device applications. This review presents recent developments in the design, synthetic routes, structural/chemical modification strategies, and applications of hybrid LDHs as multifunctional nanomaterials for overall water splitting and electrochemical supercapacitors. Recent advances in modification strategies are critically assessed to determine their effect on the physicochemical properties of hybrid LDHs. The hybrid nanostructures' alteration of energy barriers in the electrocatalytic reactions is also discussed. Finally, this review concludes with future outlooks for hybrid LDH nanostructures.
This review critically assessed the progress of hybrid LDHs nanostructure as competent multifunctional nanomaterials for energy conversion and storage systems.
Human voice recognition systems (VRSs) are a prerequisite for voice-controlled human-machine interfaces (HMIs). In order to avoid interference from unexpected background noises, skin-attachable VRSs ...are proposed to directly detect physiological mechanoacoustic signals based on the vibrations of vocal cords. However, the sensitivity and response time of existing VRSs are bottlenecks for efficient HMIs. In addition, water-based contaminants in our daily lives, such as skin moisture and raindrops, normally result in performance degradation or even functional failure of VRSs. Herein, we present a skin-attachable self-cleaning ultrasensitive and ultrafast acoustic sensor based on a reduced graphene oxide/polydimethylsiloxane composite film with bioinspired microcracks and hierarchical surface textures. Benefitting from the synergetic effect of the spider-slit-organ-like multiscale jagged microcracks and the lotus-leaf-like hierarchical structures, our superhydrophobic VRS exhibits an ultrahigh sensitivity (gauge factor, GF = 8699), an ultralow detection limit (ε = 0.000 064%), an ultrafast response/recovery behavior, an excellent device durability (>10 000 cycles), and reliable detection of acoustic vibrations over the audible frequency range (20–20 000 Hz) with high signal-to-noise ratios. These superb performances endow our skin-attachable VRS with anti-interference perception of human voices with high precision even in noisy environments, which will expedite the voice-controlled HMIs.
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IJS, KILJ, NUK, PNG, UL, UM
Osteoporosis is characterized by a reduction of the bone mineral density (BMD) and microarchitectural deterioration of the bone, which lead to bone fragility and susceptibility to fracture. ...Astaxanthin (AST) has a variety of biological activities, such as a protective effect against asthma or neuroinflammation, antioxidant effect, and decrease of the osteoclast number in the right mandibles in the periodontitis model. Although treatment with AST is known to have an effect on inflammation, no studies on the effect of AST exposure on bone loss have been performed. Thus, in the present study, we examined the antiosteoporotic effect of AST on bone mass in ovariectomized (OVX) mice and its possible mechanism of action. The administration of AST (5, 10 mg/kg) for 6 weeks suppressed the enhancement of serum calcium, inorganic phosphorus, alkaline phosphatase, total cholesterol, and tartrate-resistant acid phosphatase (TRAP) activity. The bone mineral density (BMD) and bone microarchitecture of the trabecular bone in the tibia and femur were recovered by AST exposure. Moreover, in the in vitro experiment, we demonstrated that AST inhibits osteoclast formation through the expression of the nuclear factor of activated T cells (NFAT) c1, dendritic cell-specific transmembrane protein (DC-STAMP), TRAP, and cathepsin K without any cytotoxic effects on bone marrow-derived macrophages (BMMs). Therefore, we suggest that AST may have therapeutic potential for the treatment of postmenopausal osteoporosis.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Interferon regulatory factor (IRF)-3 is known to have a critical role in viral and bacterial innate immune responses by regulating the production of type I interferon (IFN). Thymoquinone (TQ) is a ...compound derived from black cumin (
L.) and is known to regulate immune responses by affecting transcription factors associated with inflammation, including nuclear factor-κB (NF-κB) and activator protein-1 (AP-1). However, the role of TQ in the IRF-3 signaling pathway has not been elucidated. In this study, we explored the molecular mechanism of TQ-dependent regulation of enzymes in IRF-3 signaling pathways using the lipopolysaccharide (LPS)-stimulated murine macrophage-like RAW264.7 cell line. TQ decreased mRNA expression of the interferon genes
and
in these cells. This inhibition was due to its suppression of the transcriptional activation of IRF-3, as shown by inhibition of IRF-3 PRD (III-I) luciferase activity as well as the phosphorylation pattern of IRF-3 in the immunoblotting experiment. Moreover, TQ targeted the autophosphorylation of TANK-binding kinase 1 (TBK1), an upstream key enzyme responsible for IRF-3 activation. Taken together, these findings suggest that TQ can downregulate IRF-3 activation via inhibition of TBK1, which would subsequently decrease the production of type I IFN. TQ also regulated IRF-3, one of the inflammatory transcription factors, providing a novel insight into its anti-inflammatory activities.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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