The controlled actuation of gallium liquid‐metal (LM) alloys has presented new and exciting opportunities for constructing mobile robots with structural flexibility. However, the locomotion of ...current LM‐based actuators often relies on inducing a gradient of interfacial tension on the LM surface within electrolytes, which limits their application outside a liquid environment. In this work, a wheeled robot using a LM droplet as the core of the driving system is developed that enables it to move outside liquid environment. The LM droplet inside the robot is actuated using a voltage to alter the robot's center of gravity, which in turn generates a rolling torque and induces continuous locomotion at a steady speed. A series of experiments is carried out to examine the robot's performance and then to develop a dynamic model using the Lagrange method to understand the locomotion. An untethered and self‐powered wheeled robot that utilizes mini‐lithium‐batteries is also demonstrated. This study is envisaged to have the potential to expand current research on LM‐based actuators to realize future complex robotic systems.
A novel wheeled robot using a liquid metal (LM) as the core of the driving module is developed. The LM droplet within the robot is actuated using a voltage to alter the robot's center of gravity for generating a rolling torque; this induces continuous locomotion of the robot at a steady speed outside the liquid environment in both self‐driven and untethered manners.
•As of 3 March 2020, COVID-19 has spread rapidly in 46 countries, causing >90 000 confirmed cases and >2946 deaths.•Detection methods for SARS-CoV-2 include RT-qPCR and SHERLOCK technique.•Four ...structural proteins are essential for SARS-CoV-2 assembly and infection, comprising the S, M, E and N proteins.•Pangolin may be a potential intermediate host for SARS-CoV-2.•Antiviral therapy, cellular therapy, immunotherapy and Chinese medicine may be promising therapeutic strategies.
Coronavirus disease 2019 (COVID-19) originated in the city of Wuhan, Hubei Province, Central China, and has spread quickly to 72 countries to date. COVID-19 is caused by a novel coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) previously provisionally known as 2019 novel coronavirus (2019-nCoV). At present, the newly identified SARS-CoV-2 has caused a large number of deaths with tens of thousands of confirmed cases worldwide, posing a serious threat to public health. However, there are no clinically approved vaccines or specific therapeutic drugs available for COVID-19. Intensive research on the newly emerged SARS-CoV-2 is urgently needed to elucidate the pathogenic mechanisms and epidemiological characteristics and to identify potential drug targets, which will contribute to the development of effective prevention and treatment strategies. Hence, this review will focus on recent progress regarding the structure of SARS-CoV-2 and the characteristics of COVID-19, such as the aetiology, pathogenesis and epidemiological characteristics.
Conductive elastic composites have been used widely in soft electronics and soft robotics. These composites are typically a mixture of conductive fillers within elastomeric substrates. They can sense ...strain via changes in resistance resulting from separation of the fillers during elongation. Thus, most elastic composites exhibit a negative piezoconductive effect, i.e. the conductivity decreases under tensile strain. This property is undesirable for stretchable conductors since such composites may become less conductive during deformation. Here, we report a liquid metal-filled magnetorheological elastomer comprising a hybrid of fillers of liquid metal microdroplets and metallic magnetic microparticles. The composite's resistivity reaches a maximum value in the relaxed state and drops drastically under any deformation, indicating that the composite exhibits an unconventional positive piezoconductive effect. We further investigate the magnetic field-responsive thermal properties of the composite and demonstrate several proof-of-concept applications. This composite has prospective applications in sensors, stretchable conductors, and responsive thermal interfaces.
Functional nanoparticles comprised of liquid metals, such as eutectic gallium indium (EGaIn) and Galinstan, present exciting opportunities in the fields of flexible electronics, sensors, catalysts, ...and drug delivery systems. Methods used currently for producing liquid metal nanoparticles have significant disadvantages as they rely on both bulky and expensive high‐power sonication probe systems, and also generally require the use of small molecules bearing thiol groups to stabilize the nanoparticles. Herein, an innovative microfluidics‐enabled platform is described as an inexpensive, easily accessible method for the on‐chip mass production of EGaIn nanoparticles with tunable size distributions in an aqueous medium. A novel nanoparticle‐stabilization approach is reported using brushed polyethylene glycol chains with trithiocarbonate end‐groups negating the requirements for thiol additives while imparting a “stealth” surface layer. Furthermore, a surface modification of the nanoparticles is demonstrated using galvanic replacement and conjugation with antibodies. It is envisioned that the demonstrated microfluidic technique can be used as an economic and versatile platform for the rapid production of liquid metal‐based nanoparticles for a range of biomedical applications.
An innovative microfluidics‐enabled platform as an inexpensive, easily accessible method for the on‐chip mass production of eutectic gallium indium nanoparticles with tunable size distributions is developed. A novel nanoparticle stabilization approach in an aqueous medium using brushed polyethylene glycol chains with trithiocarbonate end‐groups is also investigated. Furthermore, a surface modification of the nanoparticles is demonstrated using galvanic replacement and conjugation with antibodies.
The gas‐phase clusters reaction permits addressing fundamental aspects of the challenges related to C−H activation. The size effect plays a key role in the activation processes as it may ...substantially affect both the reactivity and selectivity. In this paper, we reviewed the size effect related to the hydrocarbon oxidation by early transition metal oxides and main group metal oxides, methane activation mediated by late transition metals. Based on mass‐spectrometry experiments in conjunction with quantum chemical calculations, mechanistic discussions were reviewed to present how and why the size greatly regulates the reactivity and product distribution.
The size effect of the catalyst center plays an essential role in tuning the reactivity and selectivity during gas‐phase C−H activation. In this Concept, the authors review the size effects related to early‐transition‐metal‐oxide‐ and main‐group‐metal‐oxide‐mediated hydrogen atom ion and late‐transition‐metal‐mediated dehydrogenation reactions, focusing on the mechanistic origins of such effects based on structural and orbital analysis.
Artificial muscles possess a vast potential in accelerating the development of robotics, exoskeletons, and prosthetics. Although a variety of emerging actuator technologies are reported, they suffer ...from several issues, such as high driving voltages, large hysteresis, and water intolerance. Here, a liquid metal artificial muscle (LMAM) is demonstrated, based on the electrochemically tunable interfacial tension of liquid metal to mimic the contraction and extension of muscles. The LMAM can work in different solutions with a wide range of pH (0–14), generating actuation strains of up to 87% at a maximum extension speed of 15 mm s−1. More importantly, the LMAM only needs a very low driving voltage of 0.5 V. The actuating components of the LMAM are completely built from liquids, which avoids mechanical fatigue and provides actuator linkages without mechanical constraints to movement. The LMAM is used for developing several proof‐of‐concept applications, including controlled displays, cargo deliveries, and reconfigurable optical reflectors. The simplicity, versatility, and efficiency of the LMAM are further demonstrated by using it to actuate the caudal fin of an untethered bionic robotic fish. The presented LMAM has the potential to extend the performance space of soft actuators for applications from engineering fields to biomedical applications.
A liquid metal artificial muscle (LMAM) based on the electrochemically tunable interfacial tension of EGaIn liquid metal is demonstrated to mimic the contraction and extension of muscles. The actuating components of the LMAM are completely built from liquids, which avoids mechanical fatigue and provides actuator linkages without mechanical constraints to movement. Various proof‐of‐concept applications are demonstrated using the LMAM.
The light-emitting electrochemical cell (LEC) is an area-emitting device, which features a complex turn-on process that ends with the formation of a p-n junction doping structure within the active ...material. This in-situ doping transformation is attractive in that it promises to pave the way for an unprecedented low-cost fabrication of thin and light-weight devices that present efficient light emission at low applied voltage. In this review, we present recent insights regarding the operational mechanism, breakthroughs in the development of scalable and adaptable solution-based methods for cost-efficient fabrication, and successful efforts toward the realization of LEC devices with improved efficiency and stability.
Gallium is a metal that literally melts in your hand. It has low toxicity, near-zero vapor pressure, and a viscosity similar to water. Despite possessing a surface tension larger than any other ...liquid (near room temperature), gallium can form nonspherical shapes due to the thin, solid native oxide skin that forms rapidly in oxygen. These properties enable new ways to pattern metals (e.g., injection and printing) to create stretchable and soft devices with an unmatched combination of mechanical and electrical properties. The oxide skin can be transferred to other substrates and manipulated electrochemically to lower the interfacial tension to near zero. The reactivity of gallium can drive a wide range of reactions. The liquid state of gallium makes it easy to break into particles for making colloids and soft composites that have unusual properties due to the deformable nature of the filler. This review summarizes the truly unique and exciting properties of gallium liquid metals.
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•Sonication-induced changes of albumins from Moringa oleifera seed (MOWP) was explored.•Changes in the secondary and tertiary structure of MOWP was observable.•The MOWP was aggregated ...but not significantly degraded by ultrasound.•Ultrasonic treatment could effectively improve the thermal stability of MOWP.•Solubility, foaming and emulsifying properties of MOWP were improvement by sonication.
Effect of ultrasonic power on the structure and functional properties of water-soluble protein extracted from defatted Moringa oleifera seed were explored. The results showed that ultrasonic treatment could reduce β-sheet and β-turn content of water-soluble protein from Moringa oleifera seed (MOWP) and increase the content of random coil and α-helix. Changes in intrinsic fluorescence spectra, surface hydrophobicity (H0) and thermal behaviors indicated that ultrasonic had significant effect on the tertiary structure of MOWP. The results of SEM and SDS-PAGE showed that the MOWP was aggregated but not significantly degraded by ultrasound. The solubility, foaming properties and emulsifying properties of MOWP increased firstly and then decreased with the increase of ultrasonic power. Ultrasonic treatment altered the functional properties of MOWP, which might be attributed to the exposure of hydrophilic group and the change of and secondary and tertiary structure.
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