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Design and development of iron porphyrin-based artificial enzymes system have been attracting a lot of attention. Herein, without any toxic reductant and harsh processing, we present a facile one-pot method to fabricate bifunctional catalytic nanocomposites consisting of graphene and hemin by using vitamin C as a mild reduction reagent. The presence of graphene helps the formation of a high degree of highly active and stable hemin on the graphene surface in a monomeric form through their π−π stacking interaction. As a result, such nanocomposites possess a superior adsorption capacity and intrinsic peroxidase-like catalytic activity. Moreover, by the combination of their dye adsorption ability, RGO-hemin nanocomposites can serve as a suitable candidate for efficient capture and removal of dyes via a synergistic effect. Our findings may pave the way to apply graphene-supported artificial enzymes in a variety of fields, such as environmental chemistry, bionics, medicine, and biotechnology

The rapid capacity loss caused by the shuttling effect of polysulfides is one of the great challenges of Li–S batteries. In this work, we adopted a simple solid-phase sintering method to synthesize titanium disulfide (TiS2) and further demonstrated it as a superior modifier of separators for Li–S batteries. Two commonly adopted modification processes of separators, including vacuum filtration (VF) and slurry casting (SC) have been used to prepare TiS2/Celgard separators. TiS2-VF/Celgard can better restrain the polysulfide shuttling effect compared with TiS2-SC/Celgard. A TiS2-VF/Celgard-based Li–S battery has a reversible capacity of 771.6 mA h g−1, with a capacity retention of 645.6 mA h g−1 after 500 cycles at 2.0 C, corresponding to a capacity fading rate of ∼0.033% per cycle. This study has shown the potential of TiS2 as a multifunctional modifier of separators for high performance and long cycle life Li–S batteries.

The recent developments in wearable electronics urgently call for high-performance multi-functional fabrics for sensing and power supply. In this study, a carbonized cellulose fabric decorated by reduced graphene oxide (CCF@RGO) is fabricated into a robust and wearable multifunctional device, which demonstrates superior performance in pressure sensing and energy harvesting. The intertwined warp and weft structured cotton textiles with different structures can be converted into conductive carbon fabric while retaining their original fabric structure and natural flexibility. It is proved that graphene oxide (GO) has a promotive effect on the thermal decomposition of the cellulose fibers. Due to the buckling structure on the plain weave fabric surface, the prepared CCF@RGO based pressure sensor shows high sensitivity in a wide range. Furthermore, this conductive fabric can also be used in a single-electrode triboelectric nanogenerator (TENG) for harvesting biomechanical energy. Thus, this multifunctional CCF@RGO has potential applications in the fields of wearable electronics, artificial intelligence devices, human–machine interaction, and so forth.

Although an accurate detection of trace oil leaks is of the utmost important for soil protection, the typically used techniques fail to provide rapid assessment of less than 20 parts per million (ppm) of oil in soil. Terahertz (THz) time-domain spectroscopy, an optical method with high sensitivity to polar organics, was used to characterize the content of crude oil in soils. A linear model was built between the concentration of crude oil and the THz attenuation coefficient, which predicted the limit of detection ranging from 4.11 to 16.2 ppm. Some organics, such as aromatic and aliphatic compounds, contribute to larger absorption in the THz range than minerals. Effective-medium theory was optimized to elucidate the crude oil content dependence of THz dielectric constants. Consequently, THz technology could be an effective method for detecting trace oil leakage in soil.

In this study, a 248 nm laser was used to analyze oil shale at different pyrolysis temperatures. An induced voltage was obtained when the ultraviolet laser irradiated the oil shale surface. The las...

In this work, regenerated silk fibroin (RSF) and silicon dioxide (SiO2) composite fiber was successfully extruded by wet spinning method. The effect of SiO2 addition on structure of the composite fiber at microscopic level is studied, which subsequently correlated to the mechanical performance. The best concentration ratio for composite fiber is identified by screening SiO2 concentration from 0.025 w/w% to 0.5 w/w%. The experimental results revealed that the SiO2 at a low concentration of 0.1 w/w% was well distributed. The breaking stress, breaking strain and Young’s modulus at 0.1 w/w% SiO2 addition of the RSF fibers increased considerably compared to the neat RSF fibers from 243±3 to 458±21 MPa, 51±4 % to 54±7 % and 6.34±0.55 to 11.69±1.12 GPa, respectively. To the best of our knowledge, this is the first report for RSF/SiO2 composite fiber. We believed the insight provided in this report which looks into the structural evolution should be beneficial to the future design and building of other advanced functional fibers.

In this work, we demonstrate the principle of mesoscopic construction of silk fibroin (SF) hybrid materials, which endows the materials with new performance. In implementing this strategy, mediating molecules, wool keratin (WK) molecules, were adopted to in-line synthesize Au nanoparticles (WK@AuNPs), which further create the stable linkage of AuNPs with SF nanofibril networks via templated β-crystallization. Fourier transform infrared spectroscopy, X-ray diffraction, and atomic force microscopy demonstrate that the mesoscopic hybrid network structure of the hybrid materials is different from neat SF materials, which gives rise to various new performances, that is, long-stable fluorescence emission. As the fluorescence emission can be characteristically annealed by Cu ions, therefore be adopted as the highly selective ion probes. Moreover, as WK@AuNPs are homogeneously connected to SF nanofibril networks, the carbonization of the materials leads to secondary hybrid materials of carbon-Au, where nano-sized Au particles are well distributed in carbonized mesoscopic conductive carbon networks. Such hybrid materials of carbon-Au can be further fabricated into electrochemical (i.e., dopamine) sensors, which are demonstrated to have excellent sensing performance.

Intelligent textile that endow traditional fabric with functionalities have attracted increasing attention. In this research work, we fabricated a flexible and wearable pressure sensor with conductive nylon fabric as the electrodes and elastomer Ecoflex as the dielectric layer. The conductive nylon fabric in the twill structure, which showed a high conductivity of 0.268 Ω·cm (specific resistance), was prepared by magnetron sputtering with silver films. The flexible pressure sensor shows a high sensitivity of 0.035 kPa−1, a good linear response under pressure from 0 to 16 kPa, and a quick response time of 0.801 s. The fabricated pressure sensor was found to be highly reproducible and repeatable against repeated mechanical loads for 9500 times, with a small capacitance loss rate of 0.0534. The fabric-based flexible and wearable sensor with good properties can be incorporated into a fabric garment by the hot-pressing method without sacrificing comfort, which can then be used for human motion detecting or touch sensing. The smart glove with finger touch function was proved to be efficient in Morse code editing, which has potential for information transfer in the military field.

To report long-term safety and efficacy of combined percutaneous LAA and PFO/ASD closure.A retrospective study of 370 consecutive patients undergoing LAAC procedures using the Watchman (WM) device. Data were compared between 330 cases only with LAAC procedure (Group I) and 25/5 (PFO/ASD) cases with sequential procedures of LAAC and PFO/ASD closure (Group II).Compared to Group I, Group II had more males (86.7% vs. 65.8%, p0.05) and a higher rate of stroke (33.3% vs. 10.6%, p0.01), but there were no statistical differences in the remaining patient characteristics. During the follow-up period, there were no significant differences between the two groups in embolism events (6.1% vs. 0%, p = 0.39), device related thrombus (5.8% vs 3.3%, p = 1.0), major bleeding (9.4% vs. 6.7%, p = 1.0) and cardiac death (3.6% vs. 0%, p = 0.61). The observed rate of all thromboembolic events by Kaplan-Meier analysis was decreased by 39.9% and 100% and the observed annual rate of bleeding was reduced by 32.9% and 57.6% in Group I and Group II, respectively.LAAC combined with PFO/ASD closure might be an ideal choice to prevent stroke and other thrombotic complications in patients with both NVAF and PFO/ASD.

Li2Zn0.93Mo0.07Ti3O8@graphene conductive network is successfully synthesized via a simple solid-state reaction. The designed structure is highly advantageous to its electrochemical performance. After cycling for 600 cycles, 82.4% of the capacity for the 2nd cycle is kept at 1 A g−1. After 300 cycles, 210 and 179 mAh g−1 are obtained at 2 and 3 A g−1, respectively. Even at the high current densities of 4 and 5 A g−1, 164 and 153 mAh g−1 are still delivered at the 200th cycle, respectively. In addition, the Li2Zn0.93Mo0.07Ti3O8@graphene has good cyclic performance at the high temperature of 55 °C. The excellent cyclic performance and the large specific capacities at high rate are due to the good conductive network, stable structure, large pore volume, small particle size, and good kinetics behavior.

Purpose: Left atrial appendage closure (LAAC) may present an alternative to anticoagulation in patients with non-valvular atrial fibrillation (NVAF). However, evidence regarding benefit of LAAC in patients with prior major bleeding is limited. We evaluate whether a previous bleeding factor influences the safety and effectiveness of LAAC. Methods: A total of 377 consecutive patients scheduled for LAAC were categorized into a bleeding group (n=137) and non-bleeding group (n=240). The implantation success and prevalence of severe peri-procedural complications, and efficacy/ safety endpoints during follow-up were investigated. Results: The bleeding group had more patients ≥75 years old (P=0.044), higher CHA2DS2-VASc (P=0.029) and HAS-BLED scores (P=0.001) than the non-bleeding group. Implantation success and severe peri-procedural complications were similar. During an average 2 years’ follow-up, major bleeding events (P=0.917), all-cause death (P=0.313), co-primary efficacy events (P=0.063), and the cumulative survival ratio (P=0.828) were comparable. However, the incidence of thromboembolism was lower in the bleeding group (P=0.031). The observed thromboembolism rate was reduced by 86.1% (PConclusion: LAAC may provide a safe and effective alternative to long-term antithrombotic therapy in NVAF patients with or without prior bleeding. The efficacy of LAAC in reducing thromboembolism instead of major bleeding seems to be higher in patients with versus without prior bleeding.

The applications of enzymatic biosensors are largely limited by their relatively poor stability and short lifespan. Herein, a bio-active porous enzymatic nanofiber (PEN) membrane composed of silk fibroin nanofibrils (SFNFs) and enzymes is developed to effectively retain the enzymes in the 3D space. The 3D functional scaffolds formed by SFNFs can immobilize enzymes and provide a large surface area for molecular/ion diffusion and biochemical reactions. The PEN membrane is subsequently attached to an ultra-thin PtNPs/graphene (Pt-G) nanocomposite film to facilitate the electron transport between the enzymes and electrodes, permitting highly effective glucose and lactate sensing with long and stable performance. The as-assembled glucose and lactate sensors demonstrate high sensitivity, good cyclic reproducibility, and in particular long-term stability of up to 25 and 23.6 h, respectively. These glucose sensors have a working life that is ≈1.25-times longer than that of the best available sensors reported so far. Moreover, a wearable platform based on the sensors is developed for real-time analysis of sweat during outdoor exercising to transmit signals to a mobile handset. The high sensitivity, comfort and long-term stability of the device can benefit for long-term in-line surveillance of physiological conditions.

The rapid capacity loss caused by the shuttling effect of polysulfides is one of the great challenges of Li-S batteries. In this work, we adopted a simple solid-phase sintering method to synthesize titanium disulfide (TiS2) and further demonstrated it as a superior modifier of separators for Li-S batteries. Two commonly adopted modification processes of separators, including vacuum filtration (VF) and slurry casting (SC) have been used to prepare TiS2/Celgard separators. TiS2-VF/Celgard can better restrain the polysulfide shuttling effect compared with TiS2-SC/Celgard. A TiS2-VF/Celgard-based Li-S battery has a reversible capacity of 771.6 mA h g-1, with a capacity retention of 645.6 mA h g-1 after 500 cycles at 2.0 C, corresponding to a capacity fading rate of ∼0.033% per cycle. This study has shown the potential of TiS2 as a multifunctional modifier of separators for high performance and long cycle life Li-S batteries.

Recently, the research of aerial images, images and videos taken by UAV(unmanned aerial vehicles) have developed rapidly. People use these images to get useful information. For example, investigate the density of vehicles, analyze the development of urban suburbs. Symmetry as one of the important features of objects, has long been a research hot area in computer vision. Symmetry detection aims to extract symmetric information from given objects. Aerial images and unmanned images have their special view angle. The symmetrical characteristics of industrial design leads to the special nature of the image from the top view angle. It shows more symmetry of the object more. The objects always like airplanes, ships, automobiles or industrial products like oil drums and chimneys. An aerial object detection method based on improved YOLOv3 algorithm is proposed in this paper. First, a symmetry prior is introduced into the proposed network based on the properties of symmetry patterns. For new convolutional layer, symmetric constrains are added during the process of kernel weights update. The symmetric kernels help the proposed network to find the corresponding symmetry objects. In addition, this paper uses k-means to calculate the size of anchors in order to make the size more suitable for the size of the aerial image object. Compared with the original YOLOv3 algorithm, the improved YOLOv3 algorithm can effectively solve the missing detection of symmetry objects and improve the confidence of detection.

NiCoAl layered double hydroxide nanosheets (NiCoAl-LDHNs) were prepared by a one-step solvothermal method. The shape and size of the obtained nanosheets are optimized by adjusting the solvothermal time and the molar concentration ratio of Ni2+/Co2+ to obtain the electrode material with the best performance. When the solvothermal time is 9 h and the molar concentration ratio of Ni2+/Co2+ is 1:1, NiCoAl-LDHNs has the best morphology and electrochemical performance. When assembled into a supercapacitor, NiCoAl-LDHN-9 has a high specific capacitance of 1228.5 F g−1 at 1 A g−1. As the current density is increased to 20 A g−1, the specific capacitance is 1001.8 F g−1, which still has a high capacitance retention of 81.6%. When NiCoAl-LDHN-9 was assembled into an asymmetric supercapacitor, NiCoAl-LDHN-9//AC has a specific capacitance of 102.1 F g−1 at 0.5 A g−1. The asymmetric supercapacitor devices also show excellent electrochemical performance in terms of energy density (35.9 Wh kg−1 at 225.8 W kg−1), power density (4.8 kW kg−1 at 22.2 Wh kg−1) and cycle life (capacitance retention rate after 10,000 cycles is 87.1%). Those results indicate that NiCoAl-LDHN have the potential to be promising electrode materials for high performance supercapacitors.

Taking advantage of feature maps channels is one of the key challenges in object detection. In this study, we propose an optimization solution to further utilize the inter-channel relationship of feature maps. According to the exploration experiments, we have proposed a new Feature Maps Channel Augmentation module (FMCA) that can be inserted into mainstream structures to better establish the strong and weak dependency relationship between channels. We used comparison and ablation experiments and found that the FMCA module achieved a certain improvement under the circumstances that the detection speed was less affected. On the COCO dataset, our FMCA with ResNet-50 backbone has achieved relatively better results.

In this work, laser-induced voltage (LIV) was used to assess three various crude oils using a 248 nm ultraviolet laser. Under the same bias voltage, the peak of LIV (Vp) increased with the increase...

3D Li2ZnTi3O8 conductive network co-modified with graphene nanosheets and carbon nanotubes is successfully synthesized by a two-step reaction. The conductive structure is largely advantageous to its electrochemical performance for Li2ZnTi3O8. When cycled for 550 cycles, 81.3% and 84.2% of the capacities for the 2nd cycle is kept at 1 and 2 A g−1, respectively. After 300 cycles, 175.5, 153.3 and 144.9 mAh g−1 are obtained at 3, 4 and 5 A g−1, respectively. The excellent cyclic performance and the large specific capacities at high rate are due to the good conductive network of the Li2ZnTi3O8 active particles, large pore volume, small particle size, and good kinetics behavior.

Highlights Materials with contradictory performance were prepared using wool keratin (WK).WK used for in situ preparation of AuNPs and N-doped carbon precursor as well.Two- and three-electrode flexible strip sensors designed for pH and UA detection. Electronic supplementary material The online version of this article (10.1007/s40820-020-00459-5) contains supplementary material, which is available to authorized users., Flexible biosensors with high accuracy and reliable operation in detecting pH and uric acid levels in body fluids are fabricated using well-engineered metal-doped porous carbon as electrode material. The gold nanoparticles@N-doped carbon in situ are prepared using wool keratin as both a novel carbon precursor and a stabilizer. The conducting electrode material is fabricated at 500 °C under customized parameters, which mimics A–B type (two different repeating units) polymeric material and displays excellent deprotonation performance (pH sensitivity). The obtained pH sensor exhibits high pH sensitivity of 57 mV/pH unit and insignificant relative standard deviation of 0.088%. Conversely, the composite carbon material with sp2 structure prepared at 700 °C is doped with nitrogen and gold nanoparticles, which exhibits good conductivity and electrocatalytic activity for uric acid oxidation. The uric acid sensor has linear response over a range of 1–150 µM and a limit of detection 0.1 µM. These results will provide new avenues where biological material will be the best start, which can be useful to target contradictory applications through molecular engineering at mesoscale. Electronic supplementary material The online version of this article (10.1007/s40820-020-00459-5) contains supplementary material, which is available to authorized users.

The necessity of augmentation for oil shale explorations has led to increasing theoretical and technical requirements regarding online and direct detection of the organic content in shale. In this study, an ultraviolet laser with a wavelength of 248 nm is employed to analyze the oil shales with different oil yields and from different oil fields. Experimental results found that the laser-induced voltage (LIV) was monotonically related to the organic contents in the shale. Also, the LIV peaks linearly increased with an increase in the laser intensity and oil yield. Organics, like kerogen, and inorganic minerals reflected different energy bands. The higher the oil yield of the shale, the more the carriers were excited by the laser, indicating a stronger built-in electric potential. The microscopic structures, minerals, and kerogen were determined using a scanning electron microscope, X-ray diffraction, and Raman spectroscopy. The results showed that LIV can directly detect the organic content of oil shale fo...

Li2ZnTi3O8C@La2O3 (LZTO@C@La2O3) coated with composite protective layers is successfully fabricated via a facile solid-state route. The co-coating strategy greatly improves the electrochemical performance of LZTO. 89.8%, 77.2% and 76.7% of the discharge specific capacities for the 2nd cycle can be retained at the 200th cycle at 1, 2 and 3 A g−1, respectively. At 4 and 5 A g−1, 174.3 and 166.1 are still retained for the 100th cycle, respectively. Even at a high temperature of 55 °C, LZTO@C@La2O3 still has good cycling performance. The excellent electrochemical performance is due to the stable surface structure between LZTO and the electrolyte, a good conductive network, small particle size, and large specific surface area as well as pore volume.

Electrochromic devices (ECDs) have attracted considerable attention due to their high coloration efficiency and low power consumption. However, the development of flexible ECDs is still at a rudimentary stage due to the poor chemical stability of flexible electrodes, which prevents the fabrication of widely used WO3 electrochromic (EC) materials via traditional techniques. Herein, uniform and lamellar porous WO3 films were successfully prepared on a flexible Ag nanofiber (Ag NF) network film via a pulsed electrochemical deposition method. The sandwich structure with configuration WO3/Ag NFs/WO3 (W/Ag NFs/W) could not only protect the Ag networks from oxidation and corrosion in the oxidizing electrolyte, but also promote the electrodeposition of WO3 films in the gaps among the Ag networks. The obtained porous WO3 film is beneficial for electrolyte infiltration and alleviates mechanical stress. An 89.7% optical modulation with excellent cycling stability was achieved when the hybrid electrode was utilized as the EC film. Moreover, we demonstrated the practical suitability of our hybrid films in all-solid-state ECDs by fabricating EC sunglasses and a smart window.

Li2ZnTi3O8 (LZTO) co-doped with Mg2+–W6+ (LM6ZTW3O) has been successfully prepared by a facile one-step solid-state route. A co-doping strategy improves ionic conductivity, reduces transfer resistance, internal resistance and polarization, stabilizes the structure of LZTO and enables the LM6ZTW3O electrode to have a good electrical contact. The co-doped LZTO exhibits excellent electrochemical performance at room, high and low temperatures. At 1 A g−1, 94.7% of the capacity for the 2nd cycle is kept at room temperature after 400 cycles. At 2 A g−1, there is no capacity decay at the 300th cycle at room temperature. Even at 3 A g−1, 177.9 mA h g−1 is kept at the 120th cycle. At 55 °C, 88.3% of the capacity for the 2nd cycle is obtained at 1 A g−1. At 0 °C, 192.9 mA h g−1 is still obtained at 0.6 A g−1 for the 60th cycle, and there is no capacity decay for 200 and 300 cycles at 0.2 and 0.5 A g−1, respectively.

A novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) was identified from respiratory illness patients in Wuhan, Hubei Province, China, which has recently emerged as a serious threat to the world public health. Hower, no approved drugs have been found to effectively inhibit the virus. Since it has been reported that the HIV-1 protease inhibitors can be used as anti-SARS drugs by tegarting SARS-CoV 3CLpro, we choose six approved anti-HIV-1 drugs to investigate their binding interactions between 3CLpro, and to evaluate their potential to become clinical drugs for the new coronavirus pneumonia (COVID19) caused by SARS-CoV-2 infection. The molecular docking results indicate that, the 3CLpro of SARS-CoV-2 has a higher binding affinity for all the studied inhibitors than its SARS homologue. Two docking complexes (indinavir and darunavir) with high docking scores were futher subjected to MM-PBSA binding free energy calculations to detail the molecular interactions between these two proteinase inhibitors and the 3CLpro. Our results show that darunavir has the best binding affinity with SARS-CoV-2 and SARS-CoV 3CLpro among all inhibitors, indicating it has the potential to become an anti-COVID-19 clinical drug. The likely reason behind the increased binding affinity of HIV-1 protease inhibitors toward SARS-CoV2 3CLpro than that of SARS-CoV were investigated by MD simulations. Our study provides insight into the possible role of structural flexibility during interactions between 3CLpro and inhibitors, and sheds light on the structure-based design of anti-COVID-19 drugs targeting the SARS-CoV-2 3CLpro.

The unique properties of thin-layer transition metal dichalcogenides (TMDs) materials have been extensively investigated for both fundamental studies and practical applications in recent years. To ...

We present a strong Raman enhancement substrate through one-step thermal treatment of bulk MoS2. The substrate provides very efficient hot spots by using the rhodamine 6G (R6G) molecule as a probe. Raman and photoluminescence spectra of modified MoS2 reveal the detailed mechanism for enhancing Raman signal of R6G. It is found that both the substrate roughness and the slight chemical bond broken on the surface are the main driven forces to induce the surface enhanced Raman scattering (SERS) effects. The minimum detectable concentration of R6G on the most optimized thermally treated MoS2 can be as low as 10–8 M. This synthetic approach is facile, sensitive, and reliable, which shows great potential to be an excellent SERS substrate for biological and chemical detection.

Purification, crystallization and X-ray crystallographic analysis were employed to determine the catalytic mechanism of Est8, a GDSL-motif esterase from Bacillus sp. K91., The esterase Est8 from the thermophilic bacterium Bacillus sp. K91 belongs to the GDSL family and is active on a variety of acetylated compounds, including 7-aminocephalosporanic acid. In contrast to other esterases of the GDSL family, the catalytic residues Asp182 and His185 were more pivotal for the catalytic activity of Est8 than the Ser11 residue. To better understand the biochemical and enzymatic properties of Est8, recombinant Est8 protein was purified and crystallized. Crystals of Est8 were obtained by the hanging-drop vapour-diffusion method using 2.0 M ammonium sulfate, 5%(v/v) 2-propanol as the crystallization solution. X-ray diffraction data were collected to a resolution of 2.30 Å with an R merge of 16.4% from a crystal belonging to space group P41212 or P43212, with unit-cell parameters a = b = 68.50, c = 79.57 Å.

An Li2ZnTi3O8/graphene (LZTO/G) anode is successfully synthesized by a two-step reaction. The results show that LZTO particles can be well dispersed into the graphene conductive network. The conductive structure greatly improves the electrochemical performance of LZTO/G. When cycled for 400 cycles, 76.4% of the capacity for the 2nd cycle is maintained at 1 A g−1. Also, 174.8 and 156.5 mA h g−1 are still delivered at the 100th cycle for 5 and 6 A g−1, respectively. The excellent cyclic performance and the large specific capacities at high current densities are due to the good conductive network of the LZTO active particles, large pore volume, small particle size, low charge-transfer resistance and high lithium diffusion coefficient.

N-Doped carbon coated Li2ZnTi3O8 (LZTO@C–N) anodes have been successfully synthesized via a simple NTA-assisted solid-state method using NTA as C and N sources, as well as a chelating agent. It is shown that the N element can be doped into carbon. The N-doped carbon greatly benefits the electrochemical performance of LZTO@C–N. The initial capacities of 276.5, 271.3 and 231.9 mA h g−1 are delivered at 2, 3 and 5 A g−1, respectively, for LZTO@C–N-2 with a carbon content of 4.89%. 186.0, 177.3 and 159.7 mA h g−1 are still maintained at the 100th cycle, respectively. The good electrochemical performance of the LZTO@C–N-2 electrode at high current densities is due to its proper specific surface area and particle size, low charge-transfer resistance, and high lithium diffusion coefficient.

Li metal anode holds the key for further high-energy-density batteries. Inhibition of Li dendrites and superior electrochemical performance are critical for its practical application. Herein, a low-cost Si membrane with dual effects on 3D Ti mesh (STM) is designed through magnetron sputtering. The in situ formed Li-Si alloy layer presents highly lithiophilic and ion conductive, endowing lower nucleation barrier and homogeneous Li-ion flux, while the high electron conductive of 3D host with capacious voids immensely facilitates kinetics and relieves volume expansion. Consequently, a smooth Li layer looked like a “quilt” is uniformly formed instead of generating fair share of 1D Li whiskers. The constructed Li ‖ STM@Li symmetric cell keeps operating for 800 h at 2 mA cm−2 and 2 mAh cm−2 with a low overpotential of 25 mV. Even under carbonate-based electrolyte, the full cells using Li1.2Ni0.13Co0.13Mn0.54O2 (LNCM) as cathode can deliver a high initial capacity (245 mAh g−1) and capacity retention (81.2%) after 100 cycles at 1 C.

Turning insulating silk fibroin materials into conductive ones turns out to be the essential step toward achieving active silk flexible electronics. This work aims to acquire electrically conductive biocompatible fibers of regenerated Bombyx mori silk fibroin (SF) materials based on carbon nanotubes (CNTs) templated nucleation reconstruction of silk fibroin networks. The electronical conductivity of the reconstructed mesoscopic functional fibers can be tuned by the density of the incorporated CNTs. It follows that the hybrid fibers experience an abrupt increase in conductivity when exceeding the percolation threshold of CNTs >35 wt%, which leads to the highest conductivity of 638.9 S m-1 among organic-carbon-based hybrid fibers, and 8 times higher than the best available materials of the similar types. In addition, the silk-CNT mesoscopic hybrid materials achieve some new functionalities, i.e., humidity-responsive conductivity, which is attributed to the coupling of the humidity inducing cyclic contraction of SFs and the conductivity of CNTs. The silk-CNT materials, as a type of biocompatible electronic functional fibrous material for pressure and electric response humidity sensing, are further fabricated into a smart facial mask to implement respiration condition monitoring for remote diagnosis and medication.

Wool keratin (WK) consists of a large number of α-helices, which are just like many molecular-scale springs. Herein, the construction of 3D WK molecular spring networks are reported by cross-linking individual WK molecules via a Michael addition reaction. The as-prepared springs display a superior recovery capability with unusual nonlinear elasticity, very low dissipative energy, and turntable elastic constant achieved by adjusting the chemical crosslinking density of WK networks. Owing to these unique characteristics, the 3D WK networks based flexible strain sensors reveal a high sensitivity, broad sensing ranges, and extremely long and stable performance. While normal highly sensible strain sensors, obtained by highly sophisticated surface or bulk patterning, often exhibit a relatively narrow range of measurements and limited life cycles. Such the WK mediated sensing materials have widespread applications in wearable electronics, such as detection and tracking of different human motions, and even discern voice during speaking.

Li

N-doped carbon coated on a Li2ZnTi3O8 (LZTO@C–N) anode has been successfully synthesized via a simple surfactant-assisted solid-state method using Tween 80 as surfactant, gelatin as nitrogen source, gelatin and Tween 80 as composite carbon source, and ammonium oxalate as pore-foaming agent. It is shown that nano-sized LZTO particles (∼30 nm) are coated with a carbon layer. The N-doped carbon greatly benefits the electrochemical performance of LZTO@C–N. The largest capacities of 205.4, 193.1, 174.8 and 164.9 mA h g−1 are delivered at 2, 3, 5 and 6 A g−1, respectively. 193.2, 183.2, 159.6 and 139.9 mA h g−1 are still kept at the 100th cycle, respectively. The good electrochemical performance of the LZTO@C–N electrode at high current densities is due to its large specific surface area and pore size, small particle size, low charge-transfer resistance, high Li+ diffusion coefficient and the existence of N-doped carbon.

Carbon-coated Li2ZnTi3O8 (Li2ZnTi3O8@C) anode materials have been firstly synthesized via an EDTA-assisted solid-state route using EDTA as the carbon source and chelating agent. The effects of sintering time on the structures and physicochemical properties of the Li2ZnTi3O8@C anodes are also systematically studied. The results show that the Li2ZnTi3O8 particles are nano-sized and coated with carbon layer. The conductive carbon greatly improves the electrochemical performance of Li2ZnTi3O8@C. Li2ZnTi3O8@C-700-3 with the sintering time of 3 h delivers large specific capacities and presents good cyclic performance at high current densities. The largest capacities of 171.1 and 154.1 mAh g−1 are obtained at 4 and 5 A g−1, respectively. At the 100th cycle, 143.3 and 133.2 mAh g−1 are still kept for the sample at 4 and 5 A g−1, respectively. The good electrochemical performance of Li2ZnTi3O8@C-700-3 originates from the large pore size, proper specific surface area and particle size, and low charge-transfer resistance.

Lithium zinc titanate (Li2ZnTi3O8) anode materials have been successfully synthesized using rutile-TiO2 with different particle sizes as titanium sources via a molten-salt method. Various physical and electrochemical methods are applied to characterize the effects of TiO2 particle sizes on the structures and physicochemical properties of the Li2ZnTi3O8 materials. When the particle size of TiO2 is too small (10 nm), it is difficult to homogeneously mix TiO2 with the other raw materials. Thus, the final product Li2ZnTi3O8 has poor crystallinity, large particle size, small specific surface area, pore volume and average pore diameter, which are disadvantageous to its electrochemical performance. Using TiO2 with the proper particle size of 100 nm as the titanium source, the Li2ZnTi3O8 (R-100-LZTO) with excellent electrochemical performance can be obtained. At 1 A g−1, 175.8 and 163.6 mA h g−1 are delivered at the 1st and the 200th cycles, respectively. The largest capacities of 163, 133.3 and 122.5 mA h g−1 are delivered at 2.5, 5 and 6 A g−1, respectively. The good high-rate performance of the R-100-LZTO originates from the good crystallinity, small particle size, large specific surface area and average pore diameter, low charge-transfer resistance and high Li+ diffusion coefficient.

Wool and silk fiber are the most extensive resources of protein fibers and have been used in the textile field for many years. The extracted biocompatible proteins are more and more widely used in flexible devices, sensors, tissue engineering, etc. Here, a fully biomaterial based flexible humidity sensor has been successfully fabricated for the first time. Interdigital electrodes of humidity sensor are printed on a transparent sensor substrate made of silk protein by inkjet printing. The humidity sensitive material is gold nanoparticles hosted nitrogen doped carbon (AuNPs@NC), which is fabricated by in situ dispersion of gold nanoparticles in a wool keratin assisted porous carbon precursor. The best treatment condition of the sensitive materials is obtained by comparing the sensitivity of humidity response. Moreover, the as-prepared biocompatible flexible sensor was successfully used to detect human respiration.

Detection-based methods typically detect and locate each person on a crowd image by using a designed pedestrian target detector and obtain counting results by accumulating each detected person. However, these methods require a large amount of computational resources and are often limited by human occlusion and complex background in real scenes, resulting in inaccurate detection. Based on the characteristics of computer depth learning and population density distribution map, a more optimized pedestrian detection approach is proposed.

Catalytic and electrocatalytic applications of supported metal nanoparticles are hindered due to an aggregation of metal nanoparticles and catalytic leaching under harsh operations. Hence, stable and leaching free catalysts with high surface area are extremely desirable but also challenging. Here we report a gold nanoparticles-hosted mesoporous nitrogen doped carbon matrix, which is prepared using bovine serum albumin (BSA) through calcination. BSA plays three roles in this process as a reducing agent, capping agent and carbon precursor, hence the protocol exhibits economic and sustainable. Gold nanoparticles at N-doped BSA carbon (AuNPs@NBSAC)-modified three-electrode strip-based flexible sensor system has been developed, which displayed effective, sensitive and selective for simultaneous detection of uric acid (UA) and dopamine (DA). The AuNPs@NBSAC-modified sensor showed an excellent response toward DA with a linear response throughout the concentration range from 1 to 50 μM and a detection limit of 0.05 μM. It also exhibited an excellent response toward UA, with a wide detection range from 5 to 200 μM as well as a detection limit of 0.1 μM. The findings suggest that the AuNPs@NBSAC nanohybrid reveals promising applications and can be considered as potential electrode materials for development of electrochemical biosensors.