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The pursuit of supercapacitors with simultaneous high power and energy densities has led to extensive research and successful outcomes through the integration of three‐dimensional (3D) electrodes, encompassing both 3D active materials and 3D porous current collectors. This mini review provides a summary of recent developments in supercapacitors featuring 3D structures. The incorporation of both 3D active materials and 3D current collectors proves effective in enhancing the mass loading of active materials without compromising their specific capacitance. The presence of pores in 3D porous current collectors contributes to additional double‐layer capacitance by offering a large surface area. Moreover, 3D porous transition metal current collectors can provide both double‐layer and faradic capacitances through the in‐situ surface oxidation mechanism. Beyond materials and geometries, this review also discusses synthesis strategies for electrodes, offering insights into the process‐structure‐property relationship crucial for supercapacitors. By combining 3D active materials with 3D current collectors, the energy density of supercapacitors could be substantially improved. [ABSTRACT FROM AUTHOR]

Piezoelectric 1-3 composite materials have become extensively utilized in diagnostic ultrasound transducers owing to their high electromechanical coupling coefficient, low acoustic impedance, and low dielectric loss. In this study, Sm-doped PMN-PT ceramic/epoxy 1-3 composite with a ceramic volume fraction of 60% is fabricated by the dice-and-fill method, resulting in a high piezoelectric constant (650 pC/N) and clamped dielectric constant (2350). Utilizing the exceptionally high clamped dielectric constant, a low-frequency (12.4 MHz) ultrasound transducer is developed with a miniature aperture size (0.84 mm × 0.84 mm), exhibiting a −6 dB bandwidth of 70% and an insertion loss of −20.5 dB. The imaging capability of the miniature composite transducer is validated through both phantom and ex vivo imaging. The satisfactory results indicate that Sm-doped ceramic/epoxy composites possess significant potential for miniature devices in biomedical imaging applications. [ABSTRACT FROM AUTHOR]

The fabrication method plays a key role in the performance of lead magnesium niobate–lead titanate-based ceramics. (1 − w)[Pb(Mg1/3Nb2/3)0.67Ti0.33O3]-w[Pb1−1.5xSmx(Mg1/3Nb2/3)yTi1−yO3] piezoelectric ceramics were prepared by sintering the mixture of two different crystalline phases in which two pre-sintered precursor powders were mixed and co-fired at designated ratios (w = 0.3, 0.4, 0.5, 0.6). The X-ray diffraction results show that all the ceramics presented a pure perovskite structure. The grains were closely packed and the average size was ~5.18 μm based on observations from scanning electron microscopy images, making the ceramics have a high density that is 97.8% of the theoretical one. The piezoelectric, dielectric, and ferroelectric properties of the ceramics were investigated systematically. It was found that the properties of the ceramics were significantly enhanced when compared to the ceramics fabricated using the conventional one-step approach. An outstanding piezoelectric coefficient d33 of 1103 pC/N and relative dielectric permittivity ε33/ε0 of 9154 was achieved for the ceramics with w = 0.5. [ABSTRACT FROM AUTHOR]

In this work, the Fe3O4-carbon black filler was obtained from an in-situ coprecipitation method followed by the modification of the heptadecafluorodecyltrimethoxysilane and the Fe3O4-carbon black/poly(vinylidene fluoride) (PVDF) composites with enhanced properties were prepared by a simple solution blending-water precipitating method. The Fe3O4-carbon black distributed well in the PVDF matrix, which was confirmed by the SEM. According to the results of FTIR and WAXD, a lot of useful polar crystalline phases of PVDF formed in the Fe3O4-carbon black/PVDF composites. The electrically conductive ability, the dielectric permittivity, the dielectric loss factor, and the magnetic saturation value of the Fe3O4-carbon black/PVDF composite increased with the increasing loading amount of Fe3O4-carbon black filler. Especially, when the Fe3O4-carbon black was 5 wt.%, the dielectric permittivity of Fe3O4-carbon black/PVDF composite reached as high as 23.5 at 1000 Hz with a relatively low dielectric loss factor value of 0.38 and a magnetic saturation value of 0.64 emu/g. [ABSTRACT FROM AUTHOR]

Aqueous flexible supercapacitors have promising potential in the application of wearable electronics but are limited by their low energy densities. Typically, thin nanostructured active materials are deposited on current collectors to achieve high specific capacitances based on active materials, yet the capacitance of total electrodes is sacrificed. The fabrication of 3D macroporous current collectors is a pioneering solution to retain the high specific capacitances of both active materials and electrodes, achieving supercapacitors with high energy density. In this work, through a 'nano-reinforced concrete' method, Fe3O4–GO–Ni with a 3D macroporous structure is synthesized on the surface of cotton threads. In the synthesis process, Ni, hollow Fe3O4 microspheres and graphene oxide (GO) function as the adhesive, fillers, and reinforced and structural materials, respectively. The resultant Fe3O4–GO–Ni@cotton exhibits ultrahigh specific capacitances of 4.71 and 1.85 F cm−2 as positive and negative electrodes, respectively. The electrodes with 3D macroporous structures have good compatibility with the volume change of active materials during the charge–discharge process, leading to excellent long-cycle performance up to 10 000 charge–discharge cycles. To demonstrate the potential of practical applications, a flexible symmetric supercapacitor is fabricated using Fe3O4–GO–Ni@cotton electrodes and shows an energy density of 19.64 mW h cm−3. [ABSTRACT FROM AUTHOR]

With the rapid development of micro‐energy harvesting technology, noise has great potential as a new type of micro‐energy source by developing a high‐performance acoustic energy harvester (AEH). Nevertheless, the challenges of harvesting energy from noise are low acoustic energy density, multi‐frequency mixed sound, and unstable sound pressure. Piezoelectric‐based AEHs are proposed as a solution, but most reported devices need to work at a certain frequency and very high sound pressure, and exhibit the disadvantages of being bulky and heavy when using an extra sound‐pressure amplifier. Here, the eardrum and cochlea bioinspired polyvinylidene fluoride (PVDF) piezoelectric generator which is lightweight, compact, has a simple structure and is low‐cost, harvests multi‐frequency sound energy. Although using the commercial pure PVDF membrane, the prepared AEH still presents a high acoustoelectric conversion performance with an output power of 8.45 µW and an acoustic sensitivity of 1 V Pa−1 at 200 Hz and 100 dB without using any sound‐pressure amplifier through optimizing the structure–vibration–frequency relationship. More importantly, the bioinspired AEHs do not only exhibit the ability of acoustic energy harvesting function but also have the abilities of frequency recognition and acoustic sensing, which show great potential in the application of self‐powered acoustic sensors. [ABSTRACT FROM AUTHOR]

The effect of polydopamine (PDA) modification on aminated Fe3O4 nanoparticles (Fe3O4-NH2)/graphite oxide (GO)/β-cyclodextrin polymer cross-linked by citric acid (CDP-CA) composites were studied for the removal of a cationic dye (methylene blue, MB) and an anionic dye (Congo red, CR) from waters. The micro-structural and magnetic characterizations confirmed the successful preparation of Fe3O4-NH2/GO/CDP-CA and PDA/Fe3O4-NH2/GO/CDP-CA composites. The maximum MB and CR adsorption capacities of Fe3O4-NH2/GO/CDP-CA were 75 mg/g and 104 mg/g, respectively, while the corresponding amounts for PDA/Fe3O4-NH2/GO/CDP-CA composite were 195 mg/g and 64 mg/g, respectively. The dye sorption behaviors of these two composites were explained by their corresponding surface-charged properties according to the measured zeta potential results. Moreover, the high saturation magnetizations and the stable dye removal rate in the adsorption–desorption cycles indicated the good recyclability and reusability of the fabricated composites. [ABSTRACT FROM AUTHOR]

Photoacoustic technology is a promising tool to provide morphological and functional information in biomedical research. To enhance the imaging efficiency, the reported photoacoustic probes have been designed coaxially involving complicated optical/acoustic prisms to bypass the opaque piezoelectric layer of ultrasound transducers, but this has led to bulky probes and has hindered the applications in limited space. Though the emergence of transparent piezoelectric materials helps to save effort on the coaxial design, the reported transparent ultrasound transducers were still bulky. In this work, a miniature photoacoustic probe with an outer diameter of 4 mm was developed, in which an acoustic stack was made with a combination of transparent piezoelectric material and a gradient-index lens as a backing layer. The transparent ultrasound transducer exhibited a high center frequency of ~47 MHz and a −6 dB bandwidth of 29.4%, which could be easily assembled with a pigtailed ferrule of a single-mode fiber. The multi-functional capability of the probe was successfully validated through experiments of fluid flow sensing and photoacoustic imaging. [ABSTRACT FROM AUTHOR]

The fast capacity degradation of silicon‐based anodes significantly limits the application in lithium‐ion battery (LIB) industries. Recently, Si−CuO composites have been reported as promising anodes in terms of being cost‐effective and technically feasible, but improved cycle stability is still desired. This work introduces a proper amount of NiO into the Si−CuO composites via a facile high‐energy ball‐milling method. The study reveals that compared to the binary Si‐CuO composites, Si−CuO−NiO samples have less pronounced volume change during the cycles due to the formation of rich‐Si NiSi2. More specifically, Si87.5(CuO)3.4(NiO)9.1 shows the highest 100‐cycle capacity retention of ∼86.9 % at 0.2 C with an average coulombic efficiency of ∼99.4 %. Moreover, the thermal stability investigation demonstrates that the temperature of 600 °C is suitable to coat a carbon layer on Si87.5(CuO)3.4(NiO)9.1, where the microstructure and the uniform element distribution produced in the milling process as well as the suppression to the cr‐Li3.75Si formation can be maintained to the maximum extent, thus with further enhanced electrochemical performance. [ABSTRACT FROM AUTHOR]

Botulinum neurotoxin E (BoNT/E) is one of the major causes of human botulism and paradoxically also a promising therapeutic agent. Here we determined the co-crystal structures of the receptor-binding domain of BoNT/E (HCE) in complex with its neuronal receptor synaptic vesicle glycoprotein 2A (SV2A) and a nanobody that serves as a ganglioside surrogate. These structures reveal that the protein-protein interactions between HCE and SV2 provide the crucial location and specificity information for HCE to recognize SV2A and SV2B, but not the closely related SV2C. At the same time, HCE exploits a separated sialic acid-binding pocket to mediate recognition of an N-glycan of SV2. Structure-based mutagenesis and functional studies demonstrate that both the protein-protein and protein-glycan associations are essential for SV2A-mediated cell entry of BoNT/E and for its potent neurotoxicity. Our studies establish the structural basis to understand the receptor-specificity of BoNT/E and to engineer BoNT/E variants for new clinical applications. Botulinum neurotoxin E (BoNT/E) is a major cause of botulism and paradoxically also a drug in clinical trial. Here, the authors show that BoNT/E binding and uptake require glycosylation of its host receptor SV2 with high selectivity for SV2A and SV2B over SV2C. [ABSTRACT FROM AUTHOR]

Synthesis of three-dimensional (3D) porous current collectors is a pioneering strategy to improve the energy density and power density of wire-like supercapacitors. The strategy is further promoted in this work by synthesizing multi-scale 3D porous current collectors with secondary nanostructured metals on the surface. Through the proposed nano-'reinforced concrete' mechanism at the micron scale, Ni and graphene oxide (GO) are synergistically co-deposited on the surface of Ni wires, forming a macroporous skeleton with tunable thickness. Cu is further synthesized on the Ni-GO macroporous skeleton through a structure catalyzed electroless deposition. The resultant Cu@Ni-GO exhibits a 3D porous structure covered with secondary Cu nanosheets. Cu@Ni-GO and Ni-GO are used as current collectors for negative and positive electrodes, respectively, while active materials are in situ formed on each electrode through surface oxidation. The negative electrodes and positive electrodes exhibit excellent electrochemical performance with volumetric capacitances of 510.7 F cm−3 and 235.2 F cm−3, respectively. Asymmetric wire-like supercapacitors are also developed, showing a very high energy density of 30.2 mW h cm−3. The application potential of wire-like supercapacitors is demonstrated by powering a LED array and an electronic watch. [ABSTRACT FROM AUTHOR]

Recent research pointed out that the degree of inflammation in the adventitia could correlate with the severity of atherosclerotic plaques. Intravascular photoacoustic endoscopy can provide the information of arterial morphology and plaque composition, and even detecting the inflammation. However, most reported work used a noncoaxial configuration for the photoacoustic catheter design, which formed a limited light‐sound overlap area for imaging so as to miss the adventitia information. Here we developed a novel 0.9 mm‐diameter intravascular photoacoustic catheter with coaxial excitation and detection to resolve the aforementioned issue. A miniature hollow ultrasound transducer with a 0.18 mm‐diameter orifice in the center was successfully fabricated. To show the significance and merits of our design, phantom and ex vivo imaging experiments were conducted on both coaxial and noncoaxial catheters for comparison. The results demonstrated that the coaxial catheter exhibited much better photoacoustic/ultrasound imaging performance from the intima to the adventitia. [ABSTRACT FROM AUTHOR]

Cu2SnS3 (CSS) has gained great attraction due to its constitutive earth-abundant elements and intrinsic low lattice thermal conductivity, κ l , potentially providing high quality factor, B, and high zT value. However, the lack of band convergence is the bottleneck to enhancing the thermoelectric performance of Cu2SnS3 when performing the band engineering. To study the doping effect on the band structure and the thermoelectric performance, the composite Cu2Sn0.7Co0.3S3-xCuCl (x = 0, 0.1, 0.2, 0.3) (CSCS-xCuCl) has been investigated for the first time. The samples showed excellent data repeatability at high temperatures of up to 700 K. It was found that CuCl could compensate the Cu loss, enhance the phonon scattering and minimize the adverse effect on the power factor, PF. The ultralow lattice thermal conductivity could reach 0.38 W m−1 K−1 for the nominal composition of CSCS-0.3CuCl at 700 K. A peak zT of 0.56 (evaluated with no cold finger effect) was realized at 700 K when x = 0.3, which is almost double the performance of pristine samples. [ABSTRACT FROM AUTHOR]

Botulinum neurotoxins (BoNTs) are among the most lethal toxins known to humans, comprising seven established serotypes termed BoNT/A–G encoded in two types of gene clusters (ha and orfX) in BoNT‐producing clostridia. The ha cluster encodes four non‐toxic neurotoxin‐associated proteins (NAPs) that assemble with BoNTs to protect and enhance their oral toxicity. However, the structure and function of the orfX‐type NAPs remain largely unknown. Here, we report the crystal structures for OrfX1, OrfX2, and an OrfX1–OrfX3 complex, which are encoded in the orfX cluster of a BoNT/E1‐producing Clostridium botulinum strain associated with human foodborne botulism. These structures lay the foundation for future studies on the potential roles of OrfX proteins in oral intoxication and pathogenesis of BoNTs. [ABSTRACT FROM AUTHOR]

With the popularization of humans working in tandem with robots and artificial intelligence (AI) by Industry 5.0, ultrasonic non-destructive testing (NDT)) technology has been increasingly used in quality inspections in the industry. As a crucial part of handling ultrasonic testing results–signal processing, the current approach focuses on professional training to perform signal discrimination but automatic and intelligent signal optimization and estimation lack systematic research. Though the automated and intelligent framework for ultrasonic echo signal processing has already exhibited essential research significance for diagnosing defect locations, the real-time applicability of the algorithm for the time-of-flight (ToF) estimation is rarely considered, which is a very important indicator for intelligent detection. This paper conducts a systematic comparison among different ToF algorithms for the first time and presents the auto-diagnosis of the ToF approach based on the Defect Peaks Tracking Model (DPTM). The proposed DPTM is used for ultrasonic echo signal processing and recognition for the first time. The DPTM using the Hilbert transform was verified to locate the defect with the size of 2–10 mm, in which the wavelet denoising method was adopted. With the designed mechanical fixture through 3D printing technology on the pipeline to inspect defects, the difficulty of collecting sufficient data could be conquered. The maximum auto-diagnosis error could be reduced to 0.25% and 1.25% for steel plate and pipeline under constant pressure, respectively, which were much smaller than those with the DPTM adopting the cross-correlation. The real-time auto-diagnosis identification feature of DPTM has the potential to be combined with AI in future work, such as machine learning and deep learning, to achieve more intelligent approaches for industrial health inspection. [ABSTRACT FROM AUTHOR]

Botulinum neurotoxins (BoNTs) are among the deadliest of bacterial toxins. BoNT serotype A and B in particular pose the most serious threat to humans because of their high potency and persistence. To date, there is no effective treatment for late post-exposure therapy of botulism patients. Here, we aim to develop single-domain variable heavy-chain (VHH) antibodies targeting the protease domains (also known as the light chain, LC) of BoNT/A and BoNT/B as antidotes for post-intoxication treatments. Using a combination of X-ray crystallography and biochemical assays, we investigated the structures and inhibition mechanisms of a dozen unique VHHs that recognize four and three non-overlapping epitopes on the LC of BoNT/A and BoNT/B, respectively. We show that the VHHs that inhibit the LC activity occupy the extended substrate-recognition exosites or the cleavage pocket of LC/A or LC/B and thus block substrate binding. Notably, we identified several VHHs that recognize highly conserved epitopes across BoNT/A or BoNT/B subtypes, suggesting that these VHHs exhibit broad subtype efficacy. Further, we identify two novel conformations of the full-length LC/A, that could aid future development of inhibitors against BoNT/A. Our studies lay the foundation for structure-based engineering of protein- or peptide-based BoNT inhibitors with enhanced potencies and cross-subtypes properties. Author summary: Botulinum neurotoxins (BoNTs) are extremely toxic to humans by causing flaccid paralysis of botulism. The catalytic light chain (LC) of BoNTs is the warhead of the toxin, which is mainly responsible for BoNT's neurotoxic effects. As an endopeptidase, LC is delivered by the toxin to inside neurons where it specifically cleaves neuronal SNARE proteins and causes muscle paralysis. While the currently available equine and human antitoxin sera can prevent further intoxication, they do not promote recovery from paralysis that has already occurred. We strike to develop single-domain variable heavy-chain (VHH) antibodies targeting the LC of BoNT/A (LC/A) and BoNT/B (LC/B) as antidotes to inhibit or eliminate the intraneuronal LC protease. Here, we report the identification and characterization of large panels of new and unique VHHs that bind to LC/A or LC/B. Using a combination of X-ray crystallography and biochemical assays, we reveal that VHHs exploit diverse mechanisms to interact with LC/A and LC/B and inhibit their protease activity, and such knowledge can be harnessed to predict their specificity towards different toxin subtypes within each serotypes. We anticipate that the new VHHs and their characterization reported here will contribute to the development of improved botulism therapeutics having high potencies and broad specificities. [ABSTRACT FROM AUTHOR]

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An N-type lead telluride (PbTe0.95) thermoelectric material prepared by a conventional sintering method (CSM) has been investigated for the first time. N-type nanosized lead sulfide (PbS) fabricated using the one-pot synthesis method was embedded in the PbTe0.95 matrix to enhance the thermoelectric efficiency, zT. It was successfully demonstrated that the CSM could be used to prepare the nanosized n-type PbTe composite with the zT value of ∼1 at 673 K. This value is comparable to the one synthesized using spark plasma sintering and hot press sintering methods. We attribute the enhanced zT to the strong phonon scattering induced by the nanosized PbS. Meanwhile, the nanosized PbS particles, acting as a sintering additive, enhanced the sintering behavior of as-prepared PbTe0.95 powder. It was found that the introduction of 3 wt% nanosized n-type PbS could reduce the lattice thermal conductivity of the pristine sample of PbTe0.95 from 0.914 W m−1 K−1 to 0.59 W m−1 K−1. Finally, a single parabolic band model (SPB) demonstrated that the 3 wt% was the optimized doping amount for the PbS-doped PbTe0.95 composites. [ABSTRACT FROM AUTHOR]

Supercapacitors are characterized by high power density, but a bottleneck exists regarding their limited energy density due to the conflict between achieving high mass loading and high specific capacitance with the current structural design. Although there have been concerted efforts to develop supercapacitors with high specific capacitance using nanostructured materials, the total mass loading of active materials is confined by their nano-scale thickness. Here we report an effective strategy to integrate active materials and current collectors through binding active materials and current collectors together in a 3D style. Contrary to the conventional configuration, hollow active materials were confined inside nano-scale current collectors in this work. The resulting nano-scale electrode materials could be compressed together in a scalable style to form nanoporous Fe3O4@Ni freestanding electrodes at the desired scale. Consequently, symmetric supercapacitors were fabricated by Fe3O4@Ni electrodes, and showed a capacitance of 11.2 F cm−2, corresponding to an energy density of 94.4 mW h cm−3. The supercapacitor also exhibited an excellent cyclic capability with a capacitance retention of 107% after 10 000 cycles. The scalability of the electrode materials could be further enhanced by the addition of multiwalled carbon nanotubes (MCNTs) during the synthesis process, and the resulting 0.665-thick Fe3O4-MCNTs@Ni electrode with an Fe3O4 content of 79.4 mg cm−2 exhibited a superhigh areal capacitance of 82.6 F cm−2 as well as a high volumetric capacitance of 1242 F cm−3. This work demonstrates that large mass loading, large specific capacitance, high energy density, and good cyclability of supercapacitors can be achieved simultaneously through the effective structural design of electrodes at the multi-scale. [ABSTRACT FROM AUTHOR]

The article titled "Development of Supercapacitors with 3D Porous Structures" in the journal ChemElectroChem discusses the use of 3D interconnected nanoporous electrodes with a nano-cage structure to improve the performance of supercapacitors. This unique electrode design enhances the contact between active materials, electrolytes, and current collectors, while also mitigating the negative effects of volume change in active materials and increasing the mass loading of nanostructured active materials. The authors, Ruitao Zhou and Kwok-Ho Lam, provide further details on this concept. [Extracted from the article]

Invited for this issue's Front Cover is the group from K. H. (Koko) Lam (The Hong Kong Polytechnic University, University of Glasgow). The front cover picture illustrates 3D interconnected nanoporous electrodes featuring a nano‐cage structure, wrapping active materials within. This distinctive electrode design enhances contact between active materials, electrolytes, and current collectors. It also alleviates the adverse effect of volume change in active materials and elevates the mass loading of nanostructured active materials within the electrodes. Consequently, this nanostructure significantly enhances the overall electrochemical properties of the electrodes. Read the full text of the Concept at 10.1002/celc.202300618. [ABSTRACT FROM AUTHOR]

Sodium super ionic conductor (NASICON) materials are considered as an attractive cathode in sodium-ion batteries. Although the three-electron reactions in Na3MnTi(PO4)3 have greatly enhanced the capacity of NASICON-structured materials, the low potential from Ti3+/4+ redox reaction and undesirable initial coulombic efficiency (ICE) have inhibited its practical application. Herein, NASICON structured Na3+2xMn1+xTi1−x(PO4)3 was designed and synthesized by the atomic-ratio-controlled method. Impressively, the increase in the Mn content not only significantly enhances the average voltage, but also increases the theoretical capacity with more than three-electron reactions. Na3+2xMn1+xTi1−x(PO4)3 can deliver an extra-high capacity of 181.4 mA h g−1 at 0.1C (1C = 150 mA h g−1), and 100.4 mA h g−1 at 10C during the rate tests. When x = 0.15 and 0.2, the energy density is up to 560.2 and 539.5 W h kg−1 at 0.1C, which is significantly higher than 442.4 W h kg−1 with x = 0, i.e. Na3MnTi(PO4)3. The capacity retention is 87.4% at 1C after 500 cycles and 83% at 5C after 1000 cycles, respectively. In addition, the ICE is as high as 89.2% after the introduction of more Na ions in the pristine structure. The structural evolution and electrochemical reaction mechanism were further confirmed by ex situ XRD, XPS and TEM. This work provides a new insight into controllable design of low cost, high capacity and energy density NASICON-structured materials for SIBs. [ABSTRACT FROM AUTHOR]

With the development of high-temperature thermoelectric materials, especially the superionic copper selenide (Cu2−xSe), thermal stability and cycling thermoelectric performance have become a great concern recently. Here we demonstrate that the excellent repeatability of the thermal cycling data of a simple Cu–Se binary system can be obtained. The thermal stability was systematically studied via measuring the thermal-cycling thermoelectric performances of Cu1.97Se samples with different rates of Se evaporation by adopting a simple and controllable method, i.e., the conventional solid-state sintering method. The samples fabricated using the conventional sintering method exhibited an optimized figure of merit of 0.8 at 800 K with very good thermal repeatability and stability from 400 K to 800 K. The results indicated that the conventional sintering method can also be adopted to fabricate materials with satisfactory thermoelectric performance. It was found that the repeatability of thermal cycling data is directly related to the sintering temperature and indirectly associated with the evaporation of Se. The Cu1.97Se samples sintered at low temperatures experienced less evaporation of Se with good thermal repeatability, while they exhibited relatively low thermoelectric performance due to high carrier concentration. Although the samples sintered at high temperatures show a large variation in the thermal cycling performance, the repeatability could be improved by the further annealing process, which reveals that good thermal stability of thermoelectric materials can be obtained via post-treatment. [ABSTRACT FROM AUTHOR]

The presence of defects in thermoelectric materials plays a significant role in the modification their properties by influencing the behavior of electrons and phonons. Dopants with a unique f‐orbital can directly cause distortions in electronic density of states (eDOS) and phonon transport mechanism by intentionally inducing defects in their lattice. The theoretical and experimental outcomes of engineered vacancy defects are investigated by intentional doping of f‐block rare earth elements in β‐Zn4Sb3. Thermoelectric behavior breaks down the inverse relation and results in a parallel increase in Seebeck coefficient and electrical conductivity for β‐(Zn0.997Ce0.003)4Sb3 and β‐(Zn0.997Er0.003)4Sb3. This synergistic response triples the power factor of a thermoelectric β‐Zn4Sb3 system realized by the impurity induced resonant distortion in eDOS. From first principle GGA + U calculations, the above‐mentioned unconventional properties are attributed to the effect of doping induced vacancy formation and the formation of resonant impurity levels. Hence, it is postulated that defect engineering can be a broad strategy to improve the power factor of the system and can be extended to other thermoelectric materials. [ABSTRACT FROM AUTHOR]

Invasiveness research is an essential step in breast cancer metastasis. The application of high-frequency ultrasound microbeam stimulation (HFUMS) offers a manner of determining the invasion potential of human breast cancer cells by eliciting the elevation of transient cytoplasmic calcium ions (Ca2+). The fluorescent index (FI), which is a composite parameter reflecting calcium elevations elicited by HFUMS, was shown to be higher in invasive breast cancer cells (MDA-MB-231) compared to weakly invasive breast cancer cells (MCF-7) using the low-intensity 50-MHz HFUMS. This novel finding shows significant difference from the reported studies in which MCF-7 cells showed no response to HFUMS. In addition to the negligible response of normal human breast cells (MCF-10A), HFUMS shows the potential to be capable of differentiating the normal cells from the cancer cells. To understand the mechanism of HFUMS worked on mechanotransduction in cells, different channel blockers were used to investigate the roles of specific channels during HFUMS. It was found that GsMTx4 (30 μM), a selective blocker of mechanosensitive Piezo channels, reduces the FI values significantly in MDA-MB-231 cells, while SKF-96365 (40 μM), a general TRP channel blocker, cannot induce the significant inhibition of FI values. The results indicate that Piezo channels may play the main role in invasion and metastatic propagation of cells. [ABSTRACT FROM AUTHOR]

The electrochemical carbon dioxide (CO2) reduction (ECR) represents one of the most promising technologies for CO2 conversion into value-added feedstock from carbon monoxide (CO) to a variety of hydrocarbons. As the raw material for Fischer–Tropsch synthesis, CO is one of the most desirable ECR products and has recently received extensive research attention. Although noble metal materials, such as Au and Ag, show high selectivity towards conversion of CO2 to CO, their relative scarcity and high cost seriously limit their practical commercial application. Nanostructured carbon-based non-precious metal electrocatalysts (Nano-CNMs) are of tremendous interest in the field of ECR catalysis due to their tunable structures and electronic properties. Herein, we present an overview of recent progress in the application of Nano-CNMs, mainly including heteroatom-doped carbon, transition metal–heteroatom co-doped carbon, and carbon-based hybrid materials, with emphasis on electrocatalytic conversion of CO2 to CO. We particularly focus on discussing the structure/composition–performance relationships with regard to the electronic structure, surface properties, doping content, and associated electrocatalytic performance of various Nano-CNMs. We outline the future research directions in the development of high-selectivity ECR electrocatalysts for CO production and the stringent challenges in fundamental research and industrial application. [ABSTRACT FROM AUTHOR]

In this work, the development and performance evaluation of a high-frequency miniature ultrasonic transducer based on a Pb(Ni1/3Nb2/3)O3–Pb(Zr0.3Ti0.7)O3(PNN-PZT-based) ceramic for intravascular imaging application are reported. The fabricated PNN-PZT-based ceramic possesses ultrahigh relative clamped dielectric permittivity ($\varepsilon ^{\mathrm {S}}/\varepsilon _{0} = 3409$) and high electromechanical coupling capability ($k_{t}= 0.60$). A 42-MHz high-frequency side-looking ultrasonic transducer probe using the PNN-PZT-based ceramic with a miniature aperture of $0.33 ~\text{mm} \times0.33~\text{mm}$ was designed and fabricated, which exhibited a wide −6-dB bandwidth of 79% and an insertion loss of −19.6 dB. High spatial resolution, including the axial resolution of $36~\mu \text{m}$ and the lateral resolution of $141~\mu \text{m}$ , was determined by imaging a 13- $\mu \text{m}$ tungsten wire phantom. Ex vivo intravascular ultrasound (IVUS) imaging of a porcine coronary artery was performed to show the imaging capability of the miniature transducer. The results demonstrated the great potential of the PNN-PZT-based ceramic for high-resolution miniature transducers application. [ABSTRACT FROM AUTHOR]

Recently, acoustic levitation for non-contact micro-particle manipulation has been attracting great interest in physical, biological, and medical applications. Among the state-of-the-art manipulation technologies, single beam acoustic tweezing exhibits advantages of providing stronger trapping force and deeper penetration depth in tissues, inducing less tissue damage, and a simple configuration involving only one device. However, particle trapping by the single beam acoustic tweezer could only be operated on a smooth two-dimensional substrate, which limits the potential for real applications. Here, we report an initial attempt to acoustically levitate an individual micro-particle stably in water and manipulate the levitated micro-particle arbitrarily two-dimensionally by simply employing a 60-MHz focused ring ultrasonic transducer. The proposed working mechanism agrees well with the phenomenon. This approach could not only acoustically levitate and manipulate a micro-particle on a culture dish and on a mylar film, but could also work properly in levitating and manipulating a micro-particle placed inside the polyimide tube. This simple and low-cost approach is extremely useful for effective non-contact micro-particle manipulation without having critical concerns on the substrate properties. [ABSTRACT FROM AUTHOR]

In this work, the crystal structure, thermal conductivity, as well as dielectric and electrical properties of poly(vinylidene fluoride-co-chlorotrifluoroethylene) [P(VDF-CTFE)] filled with two different carbon nanofillers including exfoliated graphite nanoplates (xGNPs) and multi-walled carbon nanotubes (MWCNTs) have been compared. The xGNPs and the MWCNTs were well dispersed in the P(VDF-CTFE) matrix using a simple solution-blending process. The xGNPs have the ability to induce the large amount of useful polar β and γ crystal phases for P(VDF-CTFE) via the relatively strong interfacial interaction between their functional groups and the dipoles of P(VDF-CTFE), while the MWCNTs only produce the relatively low amount of β crystal phases for P(VDF-CTFE) due to their weak π-dipole interactions with P(VDF-CTFE). It was found that both the electrical conductivity and dielectric properties of xGNPs/P(VDF-CTFE) composite were better than those of MWCNTs/P(VDF-CTFE) composite. The thermal conductivities of xGNPs/P(VDF-CTFE) composites were much higher when compared with those of MWCNTs/P(VDF-CTFE) composites at the same filler content, which is probably owing to the better compatibility between xGNPs and P(VDF-CTFE). For example, the thermal conductivities of xGNPs (5 wt%)/P(VDF-CTFE) composite and MWCNTs (5 wt%)/P(VDF-CTFE) composite were 0.83 W/mK and 0.43 W/mK, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Polystyrene‐block‐polybutadiene‐block‐polystyrene triblock copolymer (SBS) has the potential to be used as a dielectric elastomer for actuator, sensor, energy harvesting, and so on, but its low dielectric constant and thermal conductivity seriously limit this application. In this study, novel exfoliated graphite nanoplates (xGNPs)/SBS composites were prepared by a solution‐blending method using N,N‐dimethylformamide and tetrahydrofuran as co‐solvents. Wide‐angle X‐ray diffraction measurement confirms that xGNPs have been incorporated into SBS. Furthermore, the result of scanning electron microscopy shows that xGNPs disperse well in the SBS matrix. The effects of xGNPs on the dielectric constant and thermal conductivity of the resultant xGNPs/SBS composites were investigated. The dielectric constant at 1,000 Hz significantly increased from 2.72 for pure SBS to 15.96 and 40.94 for xGNPs/SBS composite containing 1.19 and 1.27 vol.% of xGNPs, respectively. Moreover, the thermal conductivity of the xGNPs/SBS composite containing 1.27 vol.% of xGNPs has been improved from 0.18 to 0.41 W/m·K in comparison with that of pure SBS. [ABSTRACT FROM AUTHOR]

Abstract: Electrochemical capacitors (ECs) with high‐power capabilities and stable cycling can effectively improve the state of the art in power delivery and energy storage. In this study, we investigate reactively sputtered titanium nitride (TiN) electrodes on three‐dimensional (3D) substrates with various electrolytes and high‐rate cycling conditions. The electrode exhibits cycling stability with negligible capacitance fading after 5 000 cycles and a great rate capability, allowing the (dis)charge rate to extend from 0.1 to 10 V s−1 and retaining nearly 50 % of the capacitance in a three‐electrode system. A symmetric device made with such electrodes is capable of working at a scan rate up to 100 V s−1, yielding a remarkable power density of 4.81×105 W kg−1 at 1.60 Wh kg−1. The energy density can be pushed to 168.03 Wh kg−1 at 4.03×104 W kg−1 by replacing the aqueous electrolyte with an organic one, and this can likely be further increased by electrolyte optimization. The material synthesis and device processing suggest that 3D TiN structures can enable a new class of high‐power ECs with enhanced stability compared to their carbon‐ and pseudo‐ counterparts. [ABSTRACT FROM AUTHOR]

Abstract: Ferroelectric phase coexistence was constructed in (1−x)BaTiO3‐xCaSnO3 lead‐free ceramics, and its relationship with the piezoelectricity of the materials was investigated to ascertain potential factors for strong piezoelectric response. It is found that the addition of CaSnO3 caused a series of phase transitions in the (1−x)BaTiO3‐xCaSnO3 ceramics, and a ferroelectric coexistence of rhombohedral, orthorhombic, and tetragonal phases is formed at x = 0.08, where the ceramics exhibit the lowest energy barrier and consequently facilitate the polarization rotation and extension, resulting in the optimal piezoelectricity of d33 and kp values of 550 pC/N and 0.60, respectively. Our study provides an intuitive insight to understand the origin of high piezoelectricity in the ceramics with the coexistence of multiferroelectric phases. [ABSTRACT FROM AUTHOR]

High-voltage LiNi0.5Mn1.5O4 is a promising cathode candidate for lithium-ion batteries (LIBs) due to its considerable energy density and power density, but the material generally undergoes serious capacity fading caused by side reactions between the active material and organic electrolyte. In this work, Li+-conductive Li2SnO3 was coated on the surface of LiNi0.5Mn1.5O4 to protect the cathode against the attack of HF, mitigate the dissolution of Mn ions during cycling and improve the Li+ diffusion coefficient of the materials. Remarkable improvement in cycling stability and rate performance has been achieved in Li2SnO3-coated LiNi0.5Mn1.5O4. The 1.0 wt% Li2SnO3-coated LiNi0.5Mn1.5O4 cathode exhibits excellent cycling stability with a capacity retention of 88.2% after 150 cycles at 0.1 C and rate capability at high discharge rates of 5 C and 10 C, presenting discharge capacities of 119.5 and 112.2 mAh g−1, respectively. In particular, a significant improvement in cycling stability at 55 °C is obtained after the coating of 1.0 wt% Li2SnO3, giving a capacity retention of 86.8% after 150 cycles at 1 C and 55 °C. The present study provides a significant insight into the effective protection of Li-conductive coating materials for a high-voltage LiNi0.5Mn1.5O4 cathode material. [ABSTRACT FROM AUTHOR]

GRAPH Corrigendum: Synthesis, Electrochemistry, and Thermal Stability of High-Energy Ball-Milled Silicon-based Alloy Anodes in Lithium-Ion Batteries. [Extracted from the article]

The flagellar motor is an important virulence factor in infection by many bacterial pathogens. Motor function can be modulated by chemotactic proteins and recently appreciated proteins that are not part of the flagellar or chemotaxis systems. How these latter proteins affect flagellar activity is not fully understood. Here, we identified spermidine synthase SpeE as an interacting partner of switch protein FliM in Helicobacter pylori using pull-down assay and mass spectrometry. To understand how SpeE contributes to flagellar motility, a speE-null mutant was generated and its motility behavior was evaluated. We found that deletion of SpeE did not affect flagellar formation, but induced clockwise rotation bias. We further determined the crystal structure of the FliM-SpeE complex at 2.7 Å resolution. SpeE dimer binds to FliM with micromolar binding affinity, and their interaction is mediated through the β1' and β2' region of FliM middle domain. The FliM-SpeE binding interface partially overlaps with the FliM surface that interacts with FliG and is essential for proper flagellar rotational switching. By a combination of protein sequence conservation analysis and pull-down assays using FliM and SpeE orthologues in E. coli, our data suggest that FliM-SpeE association is unique to Helicobacter species. [ABSTRACT FROM AUTHOR]

A fairly simple and environmentally friendly hydrothermal method is reported to synthesize anode materials composed of NiFe2O4 (NFO) and ultrathin flake graphite (UFG), which are denoted as NFO/UFG composites. Several experiments were then carried out in order to determine the most beneficial proportion of UFG in the composite. Finally, it was found that the NFO/UFG-2 composite exhibits the most beneficial morphological structure which is characterized as three-dimensional floral NFO microspheres assembled by many porous nanosheets anchored on the pedestal of UFG (as determined from SEM and TEM measurements). In addition, the NFO/UFG-2 composite also demonstrates the best electrochemical performances. It shows a stable long-term cycling performance with a high initial Coulombic efficiency of 83.4 % and even obtains a high specific capacity of 963.4 mAh g−1 after 300 cycles at a current density of 200 mA g−1 and remarkable reversibility not only at low current densities but also at high current densities. Satisfyingly, the good synergy between porous NFO and UFG significantly enhances the electronic conductivity and relieves the huge bulk expansion of traditional transition metal oxide. This unique electrode material is demonstrated to be a promising candidate for the new-generation lithium ion batteries. [ABSTRACT FROM AUTHOR]

Fundamental insights into the function of the neural circuits often follows from the advances in methodologies and tools for neuroscience. Electrode- and optical- based stimulation methods have been used widely for neuro-modulation with high resolution. However, they are suffering from inherent invasive surgical procedure. Ultrasound has been proved as a promising technology for neuro-stimulation in a non-invasive manner. However, no portable ultrasound system has been developed particularly for neuro-stimulation. The utilities used currently are assembled by traditional functional generator, power amplifier, and general transducer, therefore, resulting in lack of flexibility. This paper presents a portable system to achieve ultrasonic neuro-stimulation to satisfy various studies. The system incorporated a high voltage waveform generator and a matching circuit that were optimized for neuro-stimulation. A new switching mode power amplifier was designed and fabricated. The noise generated by the power amplifier was reduced (about 30 dB), and the size and weight were smaller in contrast with commercial equipment. In addition, a miniaturized ultrasound transducer was fabricated using Pb(Mg1/3Nb2/3)O3-PbTiO3(PMN-PT) 1–3 composite single crystal for the improved ultrasonic performance. The spatial peak temporal average pressure was higher than 250 kPa in the range of 0.5–5 MHz. In vitro and in vivo studies were conducted to show the performance of the system. [ABSTRACT FROM PUBLISHER]

ABSTRACT This paper reports the fabrication, characterization, and microparticle manipulation capability of an adjustable multi-scale single beam acoustic tweezers (SBAT) that is capable of flexibly changing the size of 'tweezers' like ordinary metal tweezers with a single-element ultrahigh frequency (UHF) ultrasonic transducer. The measured resonant frequency of the developed transducer at 526 MHz is the highest frequency of piezoelectric single crystal based ultrasonic transducers ever reported. This focused UHF ultrasonic transducer exhibits a wide bandwidth (95.5% at −10 dB) due to high attenuation of high-frequency ultrasound wave, which allows the SBAT effectively excite with a wide range of excitation frequency from 150 to 400 MHz by using the 'piezoelectric actuator' model. Through controlling the excitation frequency, the wavelength of ultrasound emitted from the SBAT can be changed to selectively manipulate a single microparticle of different sizes (3-100 μm) by using only one transducer. This concept of flexibly changing 'tweezers' size is firstly introduced into the study of SBAT. At the same time, it was found that this incident ultrasound wavelength play an important role in lateral trapping and manipulation for microparticle of different sizes. Biotechnol. Bioeng. 2017;114: 2637-2647. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

De novo protein design holds promise for creating small stable proteins with shapes customized to bind therapeutic targets. We describe a massively parallel approach for designing, manufacturing and screening mini-protein binders, integrating large-scale computational design, oligonucleotide synthesis, yeast display screening and next-generation sequencing. We designed and tested 22,660 mini-proteins of 37-43 residues that target influenza haemagglutinin and botulinum neurotoxin B, along with 6,286 control sequences to probe contributions to folding and binding, and identified 2,618 high-affinity binders. Comparison of the binding and non-binding design sets, which are two orders of magnitude larger than any previously investigated, enabled the evaluation and improvement of the computational model. Biophysical characterization of a subset of the binder designs showed that they are extremely stable and, unlike antibodies, do not lose activity after exposure to high temperatures. The designs elicit little or no immune response and provide potent prophylactic and therapeutic protection against influenza, even after extensive repeated dosing. [ABSTRACT FROM AUTHOR]

Hierarchical CoMnO microspheres assembled by nanoparticles have been successfully synthesized by a facile hydrothermal method and a subsequent annealing treatment. XRD detection indicate the crystal structure. SEM and TEM results reveal the 3-dimensional porous and micro-/nanostructural microsphere assembled by nanoparticles with a size of 20-100 nm. The CoMnO electrode show initial specific discharge capacity of approximately 1546 mAh/g at the current rates 100 mA/g with a coulombic efficiency of 66.7% and remarkable specific capacities (1029-485 mAh/g) at various current rates (100-2800 mA/g). [ABSTRACT FROM AUTHOR]

High-voltage and high-performance Ni-doped LiMn2O4-basedcomposite cathodes have been obtained from the nominal formula of Li2Mn1- xNi xSiO4, synthesized by using a citric acid-assisted sol-gel method. The spinel Li(Mn,Ni)2O4 and layered Li2SiO3 coexist in the composites with x=0 and 0.05, whereas the materials with x=0.15 and 0.25 consist of Li(Mn,Ni)2O4, Li2SiO3 and layered LiNiO2; at x≥ 0.35, the impurity phases of NiO and Ni6MnO8 are detected. A significant improvement in discharge capacity and rate performance of the materials has been caused by the simultaneous existence of LiNiO2 and Li2SiO3. The composite with x=0.25 givesa very high initial discharge capacity of 168 mAh g−1 in the potential range of 3-5 V and exhibits an excellent rate performance. Our study shows that the composites consisting of Li(Mn, Ni)2O4, Li2SiO3, and LiNiO2may be promising candidates for high-voltage and high-performance lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Botulinum neurotoxins (BoNTs), which have been exploited as cosmetics and muscle-disorder treatment medicines for decades, are well known for their extreme neurotoxicity to humans. They pose a potential bioterrorism threat because they cause botulism, a flaccid muscular paralysis-associated disease that requires immediate antitoxin treatment and intensive care over a long period of time. In addition to the existing seven established BoNT serotypes (BoNT/A-G), a new mosaic toxin type termed BoNT/HA (aka type FA or H) was reported recently. Sequence analyses indicate that the receptor-binding domain (HC) of BoNT/HA is ~84% identical to that of BoNT/A1. However, BoNT/HA responds differently to some potent BoNT/A-neutralizing antibodies (e.g., CR2) that target the HC. Therefore, it raises a serious concern as to whether BoNT/HA poses a new threat to our biosecurity. In this study, we report the first high-resolution crystal structure of BoNT/HA-HC at 1.8 Å. Sequence and structure analyses reveal that BoNT/HA and BoNT/A1 are different regarding their binding to cell-surface receptors including both polysialoganglioside (PSG) and synaptic vesicle glycoprotein 2 (SV2). Furthermore, the new structure also provides explanations for the ~540-fold decreased affinity of antibody CR2 towards BoNT/HA compared to BoNT/A1. Taken together, these new findings advance our understanding of the structure and function of this newly identified toxin at the molecular level, and pave the way for the future development of more effective countermeasures. [ABSTRACT FROM AUTHOR]

Novel P(VDF-TrFE)/organosilicate composite membrane was fabricated by electrospinning. The electrospun composite membrane containing as little as 2 wt% of organosilicate demonstrated significant improvements in strength, modulus, and toughness by about 103%, 45%, and 97%, respectively, when compared with those of electrospun pure P(VDF-TrFE) membrane, while maintaining high porosity and good breathability and piezoelectricity. We believe that such an organosilicate-reinforced durable, porous, and piezoelectric P(VDF-TrFE) membrane has huge advantages in various applications such as flexible sensors, wearable electronics, filter membrane, tissue engineering, battery separator, and polymer electrolyte. [ABSTRACT FROM AUTHOR]

Porous ZnFeO nanorods have been successfully prepared by a simple spray-drying process followed by sintering. The structure and morphology of the samples were characterized by X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. The porous structured ZnFeO materials are successfully used as potential anode material for lithium-ion batteries. Electrochemical results show that the anodes exhibit good cycling performance and rate capability. The anode exhibits initial discharge capacity of approximately 1459 mAh g with an initial coulombic efficiency of 77.8% at a constant density of 100 mA g. The discharge capacity of the ZnFeO retained 1458 mA h g after 120 cycles at the current rate of 100 mA g and 456 mA h g could be obtained at the current density of 5000 mA g after 200 cycles. The discharge capacities can still be as high as 778 mAh g at a high rate of 3000 mA g. Such remarkable electrochemical properties could be ascribed to the unique porous morphology with large surface area and porosity that were beneficial to facilitate the diffusion of Li ions and electrolyte into the electrodes, meanwhile prevent volume expansion/contraction during lithiation/dislithiation processes. [ABSTRACT FROM AUTHOR]