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To construct a structure with a structure-inducing function favors the personalized design and processing of the implant. Pulse lasers provide convenient conditions for the preparation of functional structures. The laser with a wavelength of 355 nm and pulse width of 50 ns was employed to prepare the structure with cauliflower-like (C_f), sputtered droplets (S_d), and lattice (L_t) characteristics. We analyzed the influence of laser process parameters on the formation of morphology, roughness, surface chemical composition (X-ray photoelectron spectroscopy, XPS), phase, and wettability of titanium alloys. We ascertained the proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs) on C_f, S_d, and L_t structures. The results showed that multiple depositions, aggregation, and oxidation of droplets with a thick oxide layer played an essential role in forming the C_f. With the reduction of scanning speed (v) and pitch (Dy), pollutants containing O-C=O were removed, and the chemical composition of the surface gradually transformed from Ti, Ti2O3, and TiO2 to complete TiO2. The rough C_f structure had super-hydrophilic and underwater oleophobic properties, and the near-surface was mostly rutile. Nevertheless, the high interfacial tension and fractal dimension inhibited cell adhesion and proliferation. Interestingly, the stem cells had outstanding osteogenic differentiation on the surface of the S_d structure with higher hardness (450 HV) and appropriate roughness (Sa=1 μm). The L_t had a gradient of roughness and hardness at low laser spot overlap. Stem cells adhered and migrated to the ablation ring under locally amplified traction, and there was excellent osteogenic differentiation through mechanotransduction.

Thermal barrier coatings (TBCs) are facing the challenge of chloride salt hot corrosion in the marine environment. In the manuscript, 7YSZ feather-like columnar structure coatings were prepared by plasma spray-physical vapor deposition (PS-PVD). The Al2O3-modification based on in-situ synthesis was used as the strategy to improve the hot corrosion resistance of the coating. Then, the coatings were subjected to test of 900 °C NaCl thermal exposure and combustion gas-salt spray ablation. The microstructure and phase evolution results of the coatings show that NaCl has a strong corrosive effect on the as-sprayed PS-PVD TBC and leading to catastrophic oxidation. In contrast to this, the Al2O3-modified coating shows good corrosion resistance. In the hot corrosion behavior of NaCl, the metal elements in the bond layer are rapidly oxidized and accumulated on the surface of TGO layer through the electrochemical corrosion mechanism, which makes the TGO thicken rapidly. After combustion gas-salt spray corrosion, the YSZ coatings sintered and the evolution of mechanical properties were analyzed. Compared with the initial sprayed state, the hardness of the as-sprayed coating and the Al2O3-modified coating increased by 13.04 GPa and 11.47 GPa, respectively. And the elastic modulus of as-sprayed coating and Al2O3-modified coating increased by 133.00 GPa and 129.60 GPa, respectively.

The electrocaloric effect (ECE) is a promising candidate to replace the vapor-compression cooling technology, which has reached its end of improving the energy utilization efficiency. In the present work, the Y-modified BaTiO3 ceramics with nominal compositions of Ba(Ti1-xYx)O3 (abbreviated as BT-100xY, where x = 0.0125, 0.025, 0.0375, 0.050 and 0.0625) have been prepared through the conventional solid-state reaction sintering method. The dielectric properties and electrocaloric effect of BT-100xY ceramics have been investigated in detail. The XRD patterns indicate that all the BT-100xY ceramics possess pure perovskite structure without secondary phases. The temperature dependence of dielectric permittivity reveals that the BT-1.25Y, 2.5Y, 3.75Y and 5.0Y are normal ferroelectrics, and the BT-6.25Y is a relaxor ferroelectric. The ECE is calculated through the indirect equation based on Maxwell relation. The BT-2.5Y exhibits the largest ΔT = 1.26 K and the largest ΔS = 1.68 J/kg · K among all the BT-100xY ceramics, and the BT-2.5Y also exhibits the largest ΔT/ΔE = 0.296 × 10−6 K · m/V and the largest ΔS/ΔE = 0.394 × 10−6 J · m/kg · K∙V. The ECE in our work is comparable with or even larger than that of BaTiO3-based ceramics previously reported, which indicates that the BT-100xY ceramics are promising ECE materials.

π-Stacked dendrimers consisting of cofacially aligned donors and acceptors are developed by introducing three dendritic teracridan donors with orthogonal configuration and three triazine acceptors in periphery of hexaphenylbenzene skeleton. The dendritic structure and orthogonal configuration of teracridan not only make their outer acridan segments approaching to acceptor in close distance, but also fix donor and acceptor in face-to-face alignment, leading to through-space charge transfer emission with thermally activated delayed fluorescence (TADF) effect. By regulating charge transfer strength via substituent effect of acceptor, emission color of the dendrimers can be tuned from blue to yellow/red region. Solution-processed two-color white organic light-emitting diodes (OLEDs) based on blue and yellow π-stacked donor-acceptor dendrimers exhibit the maximum external quantum efficiency of 20.6 % and maximum power efficiency of 58.9 lm W-1 , representing the state-of-the-art efficiency for all-TADF white OLEDs by solution process.

An integrated approach combining scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) is used to investigate the atomic structures and electronic properties of Cr-doped ZnO( ) surfaces. When deposited at 300 K, Cr at low surface coverage (l 0.1 ML) appeared either as isolated atoms on the surface terrace of ZnO( ) or substituting Zn atoms in the ZnO lattice. Their structural models could be identified from atomic-resolution STM images and their oxidation states were found as Cr3+ based on XPS measurements. Rectangular islands nucleated at step edges along the [0001] direction could also be observed during the initial growth of Cr at 300 K and were assigned as Cr islands. The density of Cr islands as well as their average size increased with the increasing of Cr surface loading. Thermal treatments at above 600 K could facilitate the decomposition of Cr islands and the re-dispersion of Cr atoms into the ZnO lattice, indicating a strong interaction between Cr and ZnO. The adsorption of CO at 78 K showed no preferential adsorption at Cr3+ sites embedded in the surface lattice of ZnO. However, the re-dispersion of Cr atoms into the ZnO bulk at above 600 K could induce a significant upward band bending, causing a negative shift of core level XPS peaks of Zn 2p and O 1s by ~0.5–0.7 eV. Our study has thus constructed a model catalyst for Cr-doped ZnO and provided atomic insight for understanding ZnO-based catalysts.

The global arrangement of the degrees of freedom in a standard Argyris finite element method (FEM) enforces C 2 {C^{2}} at interior vertices, while solely global C 1 {C^{1}} continuity is required for the conformity in H 2 {H^{2}} . Since the Argyris finite element functions are not C 2 {C^{2}} at the midpoints of edges in general, the bisection of an edge for mesh-refinement leads to non-nestedness: the standard Argyris finite element space A ′ ⁢ ( 𝒯 ) {A^{\prime}(\mathcal{T})} associated to a triangulation 𝒯 {\mathcal{T}} with a refinement 𝒯 ^ {\widehat{\mathcal{T}}} is not a subspace of the standard Argyris finite element space A ′ ⁢ ( 𝒯 ^ ) {A^{\prime}(\widehat{\mathcal{T}})} associated to the refined triangulation 𝒯 ^ {\widehat{\mathcal{T}}} . This paper suggests an extension A ⁢ ( 𝒯 ) {A(\mathcal{T})} of A ′ ⁢ ( 𝒯 ) {A^{\prime}(\mathcal{T})} that allows for nestedness A ⁢ ( 𝒯 ) ⊂ A ⁢ ( 𝒯 ^ ) {A(\mathcal{T})\subset A(\widehat{\mathcal{T}})} under mesh-refinement. The extended Argyris finite element space A ⁢ ( 𝒯 ) {A(\mathcal{T})} is called hierarchical, but is still based on the concept of the Argyris finite element as a triple ( T , P 5 ⁢ ( T ) , ( Λ 1 , … , Λ 21 ) ) {(T,P_{5}(T),(\Lambda_{1},\dots,\Lambda_{21}))} in the sense of Ciarlet. The other main results of this paper are the optimal convergence rates of an adaptive mesh-refinement algorithm via the abstract framework of the axioms of adaptivity and uniform convergence of a local multigrid V-cycle algorithm for the effective solution of the discrete system.

Rhodomentosones A and B (1 and 2), two pairs of novel enantiomeric phloroglucinol trimers featuring a unique 6/5/5/6/5/5/6-fused ring system were isolated from Rhodomyrtus tomentosa. Their structures with absolute configurations were elucidated by NMR spectroscopy, X-ray crystallography, and ECD calculation. The bioinspired syntheses of 1 and 2 were achieved in six steps featuring an organocatalytic asymmetric dehydroxylation/Michael addition/Kornblum-DeLaMare rearrangement/ketalization cascade reaction. Compounds 1 and 2 exhibited promising antiviral activities against respiratory syncytial virus (RSV).

As a widely used orthopedic implant, titanium alloy will face the corrosion of body fluid in human body. In addition, the wear of implants and bones in human body will also reduce the service life of implants. To improve the wear resistance and corrosion resistance of biological titanium alloy, Ti6Al4V alloy was modified by plasma nitriding and plasma-enhanced chemical vapor deposition (PN + PECVD) composite process, and then samples were ablated by nanosecond laser to form a regular surface texture. The textured Ti6Al4V and PN + PECVD samples marked as Ti6Al4V-T and PN + PECVD-T samples. The microstructure and phase composition of the samples before and after modification were observed by scanning electron microscope (SEM), energy-dispersive spectrometer (EDS) and X-ray diffraction (XRD). It was found that after PN + PECVD process, a TiN film with a thickness of 2 μm was formed on the surface of Ti6Al4V. The surface texture of Ti6Al4V-T sample was regular, but the PN + PECVD-T sample texture was wide and shallow irregular after nanosecond laser ablation. The Ti–O and Ti–N–O non-stoichiometric compounds appeared on the samples after nanosecond laser ablation. Through the wear and electrochemical corrosion test in SBF, it was found that PN + PECVD sample had the best wear resistance and corrosion resistance. The wear resistance and corrosion resistance of Ti6Al4V-T and PN + PECVD-T samples were much better than that of Ti6Al4V substrate. The results show that, nitrogen oxides formed on the surface had higher microhardness and surface density, which was beneficial to improve the wear resistance and corrosion resistance of implants.

At present, optimization of mechanical properties in quenching and partitioning (Q&P) steels relies primarily on the tailoring of microstructural characteristics by manipulating the alloying elements and the Q&P process. However, adjusting the final microstructure by taking advantage of the inheritance effect derived from the initial microstructure has received less attention. Based on a typical Fe–C–Mn–Si system, the present investigation explores the effect of microstructural inheritance in an ultrahigh strength hot-rolled Q&P steel. The typical hot rolling process is followed by three cooling rates, including quenching, air cooling, and coil cooling, to obtain different initial microstructures of full martensite, bainite–austenite, and ferrite–pearlite, respectively. The same Q&P treatment is then performed to elucidate the inheritance mechanism, and the final Q&P products consist of different fractions of tempered martensite, retained austenite, bainite and fresh martensite. With decreasing cooling rates after hot rolling, the ultimate tensile strengths of the steels after the Q&P treatment are identical at ~ 1.5 GPa, while the total elongations increase gradually from 10.9, 12.7 to 14.5 pct. The highest elongation of the coil-cooled Q&P steel can be attributed to the effect of microstructural inheritance on the Q&P process and retained austenite, leading to larger austenite grain sizes and more equiaxed morphologies. The combination of austenite chemistry and morphology results in the optimal mechanical stability for retained austenite to provide continuous and durable strain hardening. Compared to cold-rolled products, hot-rolled Q&P steel is very attractive to the industry as it can potentially eliminate the cold rolling step and reduce the production cost. Utilizing the microstructural inheritance effect provides a simple and feasible route to control the microstructures and mechanical properties of ultrahigh strength hot-rolled Q&P steel.

Herein, we first design a fast low-pressure ultraviolet light irradiation strategy for easily regenerating the nearly equivalent surface vacancies. Taking the defective Bi2 O2 CO3 nanosheets as an example, nearly equal amount of oxygen vacancies can be regenerated under UV light irradiation. Synchrotron-radiation quasi in situ X-ray photoelectron spectra disclose the Bi sites in the O-defective Bi2 O2 CO3 nanosheets can act as the highly active sites, which not only help to activate CO2 molecules, but also contribute to stabilizing the rate-limiting COOH* intermediate. Also, in situ Fourier transform infrared spectroscopy and in situ mass spectrometry unravel the UV light irradiation contributes to accelerating CO desorption process. As a result, the O-defective Bi2 O2 CO3 nanosheets achieve a stability up to 2640 h over 110 cycling tests and a high evolution rate of 275 μmol g-1 h-1 for visible-light-driven CO2 reduction to CO.

Source apportionment offers an efficient way to identify emission sources and the contributions to air pollution. It helps to deepen our understanding of the air pollution formation process and develop productive environmental policies. Accurate PM2.5 source apportionment is more essential for small-scale local air pollution control. An integrated source apportionment approach was built by combining chemical mass balance (CMB) model and the Community Multiscale Air Quality modelling system (CMAQ) model to complement individual model and apportion PM2.5 pollution into more elaborate emission sources categories. The CMAQ source apportionment results of corresponding PM2.5 precursors were applied to assign secondary components while that of PM2.5 were applied to assign non-local sources as the basic constrains. An island city with typical secondary components in PM2.5 pollution was chosen. The results showed the dominant source impacts of non-local sources ranged from 31.07% in summer to 49.60% in winter. Compared to individual model, the integrated source apportionment approach preserved the accuracy of CMB modelling for primary sources, simultaneously apportioned the secondary components to the primary sources and abstracted non-local sources from primary sources, which acquired more elaborate results. The results further helped develop more efficient air quality control policies.

In this article, a micro-heterogeneous material simulation model with carbon fiber and resin phase about laser ablation on carbon fiber reinforced plastic (CFRP) is established by Ansys. The ablation process of CFRP by nanosecond ultraviolet laser is simulated, and the mechanism of pulse energy and spot spacing on the heat-affected zone (HAZ) is studied, then the process parameters are optimized with the goal of HAZ size and processing efficiency, and finally the validity of the model is verified by experiments. It is found that the residual gradient and the width of the radial HAZ increase with the increase of the spot spacing, and the width of the axial HAZ decreases slightly with the increase of the spot spacing, which indicates the existence of the optimal spot spacing. Second, the ablation depth increases with the increase of the pulse energy, and the carbon fiber retains a relatively complete degree of exposure when the pulse energy is low, which has a certain guiding significance for the cleaning and bonding of CFRP.

In this study, 84 scenes Sentinel-1A satellite datasets from October 2016 to September 2019 were used to analyze surface deformation in East Dongting Lake, China, by employing the small baseline subset interferometric synthetic aperture radar (SBAS-InSAR) method. The data are divided into two seasons, i.e., the flood and dry seasons. It was suggested that the surface deformation is related to the distribution of the river network and water flow activities. During the dry season, the water flow is active along the internal river, scouring the surrounding soil. During the flood season, the water flow basically occurs around the external drainage network. By qualitatively comparing surface deformation and precipitation changes as well as changes in soil erosion, it is found that the deformation was highly related to soil erosion and seasonal precipitation. The precipitation in the flood period is heavy than that in the dry season. Therefore, the runoff with amount silt will scour the soil in the passing area, resulting obvious surface deformation. During the dry period, surface deformation is smaller due to the less precipitation.

Biological macromolecules always function through a collective behavior of the aggregated constituents, which usually are self-assembled together via noncovalent interactions. Likewise, artificial supramolecular assemblies, whose properties and functions are mainly derived from their primary and secondary structures, may also aggregate into high-order architectures with emergent functions not available on the individual components. Here we report the first example of an insulin-like hexamerization of lanthanide triple helicates toward a 4 nm diameter hexameric capsule via consecutive metal-directed and anion-directed assembly processes. Hierarchical chiral-sorting self-assembly endows hexamers with aggregation-induced stability and emission enhancement. Furthermore, emergent guest-encapsulation function and enantioselectivity toward terpene drugs have been realized in the late-formed central cavity of the hexamers. This study not only provides a feasible strategy for constructing sophisticated and multifunctional lanthanide-organic materials but also sheds some light on the self-assembly processes in nature.

Strong metal-support interactions (SMSI) is an important concept in heterogeneous catalysis. Herein, we demonstrate that the Au-TiO2 SMSI of Au/TiO2 catalysts sensitively depends on both Au nanoparticle (NP) sizes and TiO2 facets. Au NPs of ca. 5 nm are more facile undergo Au-TiO2 SMSI than those of ca. 2 nm, while TiO2 {001} and {100} facets are more facile than TiO2 {101} facets. The resulting capsulating TiO2-x overlayers on Au NPs exhibit an average oxidation state between +3 and +4 and a Au-to-TiO2-x charge transfer, which, combined with calculations, determines the Ti:O ratio as ca. 6:11. Both TiO2-x overlayers and TiO2-x -Au interface exhibit easier lattice oxygen activation and higher intrinsic activity in catalyzing low-temperature CO oxidation than the starting Au-TiO2 interface. These results advance fundamental understanding of SMSI and demonstrate engineering of metal NP size and oxide facet as an effective strategy to tune the SMSI for efficient catalysis.

Understanding the interactions between metallic lithium (Li) and the anchoring sites/groups is essential for the design of stable host materials and artificial interphases in lithium metal batteries (LMBs). Here, we investigate the interactions of lithium with the polar organic functional groups in copper(II) hexadecafluorophthalocyanine (F16CuPc) and copper(II) phthalocyanine (CuPc) through the combination of in-situ X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), synchrotron-based near-edge X-ray absorption fine structures (NEXAFS), and density functional theory (DFT) calculations. It is revealed that the highly polar C-F bonds can anchor the Li atom via ionic Li-F interaction around the outer aza bridge N atoms in F16CuPc, while Li tends to interact with the inner pyrrolic N atoms around the central Cu in CuPc. The central Cu(II) ions in both molecules are reduced to Cu(I) upon interaction with Li. Electrons are transferred from Li to the lowest unoccupied molecular orbitals (LUMO) of both F16CuPc and CuPc molecules, as revealed by the UPS and NEXAFS measurements. Our systematic study can shed light on the design of anode materials by adding polar functional groups for applications in lithium metal batteries (LMBs). Ministry of Education (MOE) The authors acknowledge the financial support from the Natural Science Foundation of China (U2032147), Singapore MOE Tier II grant R143-000-A29-112, and Academic Research Fund Tie I grant RG104/18.

Realization of the Kagome antiferromagnetic (KAF) lattice is of high interest because the geometric frustration in the Kagome lattice is expected to give rise to highly degenerated ground states that may host exotic phases such as quantum spin liquid. Here we demonstrate the design and synthesis of a single-layer two-dimensional metal-organic framework (2D-MOF) containing a Kagome lattice of Fe(II) ions assembled on a Au(111) surface. First-principles calculations reveal that the Fe(II) ions are at a high spin state of S = 2 and are coupled antiferromagnetically with nearest-neighboring exchange J1 = 5.8 meV. The ground state comprises various degenerated spin configurations including the well-known q = 0 and q = √3 × √3 phases. Remarkably, we observe a spin excitation at 6 meV using tunneling spectroscopy. This work points out a feasible route toward realizing spin 1/2 KAF, a candidate quantum spin liquid system, by replacing Fe(II) by Cu(II) in the same structure.

Interest in layered perovskite quantum wells is motivated by their potential for use in optoelectronic devices. In these systems, the smallest and largest quantum wells are most concentrated near o...

Variant selection during the martensitic transformation in steels may play an important role in determining the transformation kinetics and the resulting mechanical properties. In this study, the variant selection and crystallographic features of deformation-induced martensite were investigated by quasi in situ electron backscatter diffraction (EBSD) in grade SUS321 during tensile deformation. Significant differences in variant selection between austenite (γ)→hcp-martensite (e)→bcc-martensite (α’) and γ→α’ transformation routes were observed and reported in detail, which demonstrated that e-martensite plays an important role in the variant selection of α’. Variant selection at different deformation stages was also analysed and revealed that α’ variants with the highest priority and variant pairs were preferred at the initial and last deformation stages in the γ→e→α’ sequence, respectively. Meanwhile, the single α’ variant nucleated at the thin slip band keeps its crystallography feature upon further deformation in the γ→α’ sequence. In addition, the strain work of the martensitic transformation for applied loads was quantitatively estimated to explain the variant selection and associated mechanism. When these calculations are compared to the experimental results it is found that they are not able to predict which α’ variant is forming preferentially during either during the γ→α’ or the e→α’ sequences, while only accurate predictions are obtained for the γ→e transformation which indicates that the γ→α’ variant selection is more complex.

In this paper, the first family of conforming discrete three dimensional Gradgrad-complexes consisting of finite element spaces is constructed. These discrete complexes are exact in the sense that the range of each discrete map is the kernel space of the succeeding one. These spaces can be used in the mixed form of the linearized Einstein-Bianchi system.

Crown ethers are a class of macrocyclic molecules with unique flexible structures but they are rarely integrated in covalent organic frameworks (COFs). To date, employing flexible organic units such as crown ethers to construct COFs with high crystallinity and surface area are still a challenge. In this work, two new COFs with different flexible crown ethers as backbone rather than side chains are synthesized and further employed for alkali metal ions separation. Both of COFs possess high surface areas, good crystallinity, and excellent chemical stability. Interestingly, these two new COFs with 18-crown-6 or 24-crown-8 units showed remarkable binding ability of K+ or Cs+ owing to the size-fit effect. This work demonstrated that the unique structural features of crown ethers will lead to increase interest in fabricating COFs with crown ethers.

A flow erosion model of water inrush was developed that couples the Darcy, Forchheimer, and Navier–Stokes fields under the theory of continuum mechanics. Water flow and fluidized particles were regarded as single-phase mixed fluids based on the fundamentals of flow transition (aquifer laminar flow to turbulent flow) being the main cause of mine water inrush; the effects of rock disintegration and the coupled effects of flow and erosion were incorporated. The water source of the aquifer, water-inrush channel of the fracture network, and flow path of the slope roadway export were organically connected in a unified flow field. The weak integral forms of the Darcy, Forchheimer, and Navier–Stokes equations were constructed according to the principle of virtual displacement. The convective terms were discretized by the finite volume method and the other terms were discretized by the finite element method; the calculation source program was developed based on the finite element language and its compiler (FELAC). The source program system was used to numerically simulate water inrush in a fractured zone in the Jiangjiawan Mine. It reproduced the entire dynamic process of a water inrush and revealed the distribution and variation characteristics of the pressure field, velocity field, porosity, and concentration, as well as the mechanisms underlying the sudden change in water flow.

The late Mesozoic tectonic domain of Southeast China transitioned from compression to extension because of the Paleo-Pacific plate rollback. However, the precise timing of the initiation of extensi...

Although Botrytis fragariae was only recently identified as a new Botrytis species that causes strawberry gray mold, its prevalence extends to many states of the eastern United States. Compared with B. cinerea, which is known to be the causal agent of gray mold on many crop plants including strawberry, B. fragariae appears to have specifically adapted to strawberry and exhibits distinct fungicide sensitivity. This is the first presentation of a high-quality genome assembly of B. fragariae with gene annotation based on sequence homology and deep transcriptome data. The genome sequence information from B. fragariae is expected to help reveal genomic features underlying its host specialization and evolution of distinct fungicide resistance and other novel pathogenicity mechanisms.

The TanDEM-X DEM is a valuable data source for estimating glacier mass balance. However, the accuracy of TanDEM-X elevation over glaciers can be affected by microwave penetration and phase decorrelation. To investigate the bias of TanDEM-X DEMs of glaciers on the Tibetan Plateau, these DEMs were subtracted from SPOT-6 DEMs obtained around the same time at two study sites. The average bias over the studied glacier areas in West Kunlun (175.0 km2) was 2.106 ± 0.012 m in April 2014, and it was 1.523 ± 0.011 m in Geladandong (228.8 km2) in October 2013. By combining backscatter coefficients and interferometric coherence maps, we found surface decorrelation and baseline decorrelation can cause obvious bias in addition to microwave penetration. If the optical/laser data and winter TanDEM-X data were used as new and historic elevation sources for mass-balance measurements over an arbitrary observation period of 10 years, the glacier mass loss rates in West Kunlun and Geladandong would be potentially underestimated by 0.218 ± 0.016 and 0.158 ± 0.011 m w.e. a−1, respectively. The impact is therefore significant, and users should carefully treat the bias of TanDEM-X DEMs when retrieving a geodetic glacier mass balance.

Background Aflatoxins are one of the maximal menaces to food safety and public health and can contaminate food during the entire process from field to table, which can then be digested by the consumer, causing irreversible negative impacts such as immunotoxic, carcinogenic, and mutagenic effects. Therefore, development of novel technology to decontaminate aflatoxins is obviously important for the food industry. Cold plasma (CP) is an emerging novel nonthermal technology with eco-friendliness, high-efficiency and low cost, which has recently been widely studied for inactivating microorganisms and mycotoxins. Scope and approach This review presents a brief overview of aflatoxins and cold plasma treatment (CPT) and provides detailed information on the blocking and degradation of aflatoxins by CPT and its potential mechanisms. Furthermore, the superiority of CPT in purifying aflatoxins is highlighted by comparison with conventional methods including physical, chemical and biological treatments. Finally, the limitations and challenges of CPT are also discussed. Key findings and conclusions Recent studies show that CPT is an alternative technique to conventional methods for aflatoxins decontamination. However, the effective components and exact sites where CPT works are not completely clear, and the types of food researched are also few. Further researches should focus on breaking through these bottlenecks and provide a theoretical basis for the promotion of CPT applications.

It has been of interest in seeking electrocatalysts that could exercise equally high-efficient and durable hydrogen evolution upon nonselective electrolytes in both acidic and alkaline environments. Herein, we report a facile strategy to fabricate cobalt tungsten phosphides (CoxW2−xP2/C) hollow polyhedrons with tunable composition based on metal-organic frameworks (MOFs) template method. By the deliberate control of W doping, the synthesized catalyst with the composition of Co0.9W1.1P2/C is found to be able to achieve a current density of 10 mA·cm−2 at overpotentials of 35 and 54 mV in acidic and alkaline media, respectively. This combined electrochemical property stands atop the state-of-the-art electrocatalyst counterparts. To unveil the peculiar behavior of the structure, density functional theory (DFT) calculation was implemented and reveals that the surface W-doping facilitates the optimization of hydrogen absorption free energy (ΔGH*) as well as the thermodynamic and kinetics barriers for water dissociation, which is coupled with the hollow structure of Co-W phosphides, leading to the prominent HER catalytic performance. Ministry of Education (MOE) This work was supported by the National Science Foundation for Young Scientists of China (No. 51901018), China Postdoctoral Science Foundation (No. 2019M660456), the National Natural Science Foundation of China (Nos. 51771027 and 21676216), Young Elite Scientists Sponsorship Program by China Association for Science and Technology (YESS, 2019QNRC001), the Fundamental Research Funds for the Central Universities (No. FRF-MP-19-001), National Key Research and Development Program of China (No. 2017YFB0702100) and Singapore MOE AcRF Tier 1 grant M4011528.

Electric-field (EF) microsensors with high resolution are crucial for the realization of real-time dynamic status monitoring of Ubiquitous Power Internet of Things (UPIoT), which is of great significance for the safe operation of power system and early-stage diagnostics of power equipment. Distortion-free and high-resolution measurement of electric fields is also important in applications such as meteorological monitoring and aerospace launch. Existing electric-field measurement methods are always costly, bulky, and low in resolution. We presented a capacitive EF sensor with small size and high resolution. The presented sensor is based on piezoelectric effect, and a micro cantilever structure is realized using microfabrication. Simulation and experimental results indicate that the presented sensor has a resolution of about 45 V/m and a measurable magnitude of over 1.5 MV/m. Owing to the characteristics of small size, low cost and low power consumption, the EF sensor is suitable for applications of large-scale sensing arrays.

China and the United States are the world’s top two greenhouse gas emitters. However, little is known as to the amount of attention the media in both countries have paid to the issue of climate change, and the ways in which their media framed the issue. To address both queries, this study analyzed the climate change coverage ( N = 9,001) of the Chinese and US media, using a computational approach. Results revealed overall increases of attention to climate change in both countries’ media from 2016 through 2019, whereas the Chinese witnessed a more evident increase after 2018. Moreover, the media in both countries tended to foster a sense of responsibilities rather than confining the issue to an episodic level. Furthermore, the US media highlighted political conflict and the catastrophic consequences of climate change, whereas the Chinese media highlighted public accountability and governance, as well as economic development and competitiveness.

A bacterium was newly isolated from cow dung, and identified as Enterococcus faecium YA002 by 16S rRNA gene sequence analyzing. It showed high H2 production performance in dark fermentation with xylose as substrate, the fermentative conditions including xylose concentration, ratio of nitrogen source to carbon source in mass (N/C ratio), temperature, and initial pH were optimized by response surface methodology (RSM) with a Box-Behnken design (BBD). After regression analyzing, it could be found that H2 production was well fitted by a quadratic polynomial equation, and significantly affected by the four studied factors. The optimal conditions were xylose concentration of 22.69 g/L, N/C ratio of 0.127, temperature of 37.2 °C, and initial pH of 8.0, and the experimental H2 production under the conditions was 2918.91 ± 125.49 mL/L, which was 97.91% of the predicted H2 production. The results indicated that Enterococcus faecium YA002 was an ideal inoculum for dark fermentative H2 production from xylose, and the conditions for the H2 production were successfully optimized by response surface methodology.

Check-dams are the most important measure to control the soil and water loss in highly erodible catchments on the Chinese Loess Plateau. Based on the data of check-dams from 1950 to 2014, our study roundly analyzed the regional distribution, function and the problems of check-dams on the Loess Plateau. A total of 17,094 check-dams with a storage capacity of over 100,000 m3 and an average density of 0.027 counts km−2 were installed on the Loess Plateau. Check-dams’ densities varied greatly in the Qinghai Province, Gansu Province, Ningxia Hui Autonomous Region, Inner Mongolia Autonomous Region, Shaanxi Province, Shanxi Province and Henan Province. The highest density of check-dams reached 0.088 counts km−2 in Shaanxi Province, whereas the lowest density of check-dams was only 0.005 counts km−2 in Qinghai Province. However, after decades of operation, 3025 large check-dams and 2257 medium check dams are dangerous and have security risks, which are seriously threatening downstream safety. The dangerous rate of check-dams is high. Specifically, the check-dams in Shanxi and Qinghai Province have the highest dangerous rates, with both exceeding 53%. Therefore, there is an urgent need for carrying out reinforcement of the dangerous check-dams. The results are helpful to policymakers to extend and develop check-dams.

In recent years, high spatial resolution remote sensing technology has made significant progress. High-resolution remote sensing satellites provide great convenience for high-quality image acquisition. In order to adapt to changes in the appearance of the target, mainstream tracking algorithms often use pattern recognition methods to build a target appearance model with learning capabilities, and use the image frames acquired during the tracking process to update the appearance model. This paper mainly studies the object-oriented remote sensing image information extraction method based on multi-classifier combination and deep learning algorithm. In this paper, we use the splitting mechanism of the tree structure to retain the appearance model with diversity, and through the integrated learning integration strategy, the target position is collaboratively predicted. Through the comparative analysis on the OTB and VOT platforms, the algorithm works well when the requirements of the tracking standards are low (the accuracy threshold is greater than 20 pixels and the success threshold is less than 0.4 pixels). The experimental results in this paper show that compared with other advanced classification methods, the proposed method shows better generalization performance in accuracy, recall, f-measure, g-mean and AUC.

A flower-like nanostructured MnO2 with near-infrared (NIR) light-triggered high photothermal conversion capability of 30% and reactive oxygen species (ROS) generation ability was successfully developed. Different from the reported MnO2 nanomaterials those were used in the nanomedicine field for only relieving tumor hypoxia and/or imaging, the flower-like MnO2 inherently acts as a competent agent for simultaneously enhanced photothermal and photodynamic therapy. A flower-like nanostructured MnO2 with near-infrared (NIR) light triggered high photothermal conversion capability of 30% and reactive oxygen species (ROS) generation ability was successfully developed.

Carbon fiber reinforced epoxy is the most commonly used carbon fiber composite, and it has superior performance. However, the growing demand for carbon fiber reinforced epoxy results in the huge consumption of petroleum products and intractable disposal problems, which have a heavy burden on the environment and affect the sustainable development of humans. To address this dilemma, in this work, recyclable carbon fiber composites were prepared using full biobased dynamic crosslinked matrices from natural camphoric acid (CPA) and epoxidized soybean oil (ESO) without additional chemical modification. As the dynamic CPA/ESO networks could be topologically rearranged via transesterification reactions (TERs), the composite laminates possessed usable performance at room temperature, and could be easily reprocessed, self-adhered, and repaired at elevated temperatures. In addition, the carbon fibers could be fully recycled via degrading the composites using ethylene glycol, where the recycled fibers maintained nearly 100% of the mechanical properties possessed by virgin samples. This work prepared recyclable carbon fiber composites using full biobased epoxy matrices for the first time, which offered a green and convenient strategy for designing recyclable eco-materials.

Nano-resolution synchrotron X-ray spectro-tomography has been demonstrated as a powerful tool for probing the three-dimensional (3D) structural and chemical heterogeneity of a sample. By reconstructing a number of tomographic data sets recorded at different X-ray energy levels, the energy-dependent intensity variation in every given voxel fingerprints the corresponding local chemistry. The resolution and accuracy of this method, however, could be jeopardized by non-ideal experimental conditions, e.g. instability in the hardware system and/or in the sample itself. Herein is presented one such case, in which unanticipated sample deformation severely degrades the data quality. To address this issue, an automatic 3D image registration method is implemented to evaluate and correct this effect. The method allows the redox heterogeneity in partially delithiated Li x Ta0.3Mn0.4O2 battery cathode particles to be revealed with significantly improved fidelity.

Epoxy vitrimers based on transesterification reactions (TERs) are a type of recyclable thermosets which have been developed sucessfully in recent years. However, the good thermal performance and the fast network rearrangements are somehow contradictory and difficult to achieve simultaneously in TER-based epoxy vitrimers. This contradiction has been resolved in this work by use of a green and simple, yet effective strategy, where natural glycyrrhizic acid (GL) with sebacic acid (SA) were used as curing agents to prepare epoxy vitrimers based on TERs with different monomer compositions (V1 to V5). Thanks to the unique structure of GL, the glass transition temperatures (Tg) of the vitrimers rose from 31 to 89 °C, and their stress relaxation time shortened from 390 to 130 s at 180 °C with the increase of GL content. In particular, the vitrimer V4 exhibited good thermal stability (a decomposition temperature Td5 of 263 °C), fast stress relaxation (a relaxation time of 130 s at 180 °C), low malleability temperature (a Tmall of 116 °C) and usable Tg (61 °C). Moreover, this vitrimer could be welded, reprocessed, repaired, recycled and chemically degraded at a relatively mild temperature (130 °C). This work provides a green strategy for vitrimer design, which might benefit the preparation of recyclable thermosets with a highly comprehensive performance in the future.

Inorganic nanomaterials (NMs) have shown potential application in tumor-targeting theranostics, owing to their unique physicochemical properties. Some living cells in nature can absorb surrounding ions in the environment and then convert them into nanomaterials after a series of intracellular/extracellular biochemical reactions. Inspired by that, a variety of living cells have been used as biofactories to produce metallic/metallic alloy NMs, metalloid NMs, oxide NMs and chalcogenide NMs, which are usually automatically capped with biomolecules originating from the living cells, benefitting their tumor-targeting applications. In this review, we summarize the biosynthesis of inorganic nanomaterials in different types of living cells including bacteria, fungi, plant cells and animal cells, accompanied by their application in tumor-targeting theranostics. The mechanisms involving inorganic-ion bioreduction and detoxification as well as biomineralization are emphasized. Based on the mechanisms, we describe the size and morphology control of the products via the modulation of precursor ion concentration, pH, temperature, and incubation time, as well as cell metabolism by a genetic engineering strategy. The strengths and weaknesses of these biosynthetic processes are compared in terms of the controllability, scalability and cooperativity during applications. Future research in this area will add to the diversity of available inorganic nanomaterials as well as their quality and biosafety.

The integration of carbon capture and CO2 utilization could be a promising solution to the crisis of global warming. By integrating calcium-looping (CaL) and the reverse-water-gas-shift (RWGS) reaction, a high-temperature CO2 capture and in situ conversion technology is successfully realized in one fixed-bed column at the same operating temperature of 650 °C. Inspired by the heterojunction photocatalytic mechanism, the heterojunction-redox catalysis strategy is proposed for the first time by doping the bimetallic Fe3+/Fe2+ and Co3+/Co2+ redox couples into a hierarchical porous CaO/MgO composite. The presence of different valence states of doped Fe and Co oxides not only provides extra oxygen vacancies to facilitate CO2 adsorption, and hence adsorption enhanced conversion (AEC), but also significantly lowers the electric potential difference of Fe3+/Fe2+ through the newly formed Fermi level in Fe5Co5Mg10CaO, which makes electron spillover easier to improve the catalytic activity in the RWGS reaction for CO2 conversion. More importantly, with the high-temperature refractory MgO and the highly disperse Fe and Co oxides in Fe5Co5Mg10CaO, the problem of CaO sintering is successfully solved. An excellent and stable high-temperature CO2 capture capacity of 9.0–9.2 mmol g−1, an in situ CO2 conversion effeciency near 90% and a CO selectivity close to 100% are achieved in the integrated CaL/RWGS process. In addition, experimental and simulation scale-up studies further demonstrate its pratical scalability. Economic evaluation reveals that the integrated CaL/RWGS technology is much more cost-effective than the individual CaL and RWGS processes. Therefore, the heterojunction-redox strategy provides a unique way to design bifunctional adsorbent/catalyst materials. The integrated CaL/RWGS process could be a promising technology for CO2 capture and utilization.

Aqueous full K-ion batteries (AFKIBs) featuring high safety, low cost, and environmental friendliness represent the future of advanced energy storage technologies. However, current AFKIB systems are still in need of suitable electrolytes and electrode materials, not to mention durability. Here, we report a “rocking-chair” type aqueous full K-ion system with KTi2(PO4)3/C crystalline nanoparticles as the anode material with near zero-strain, iron hexacyanoferrate as the cathode, and 21 m KCF3SO3 as a water-in-salt electrolyte. Benefitting from the fast reaction kinetics and high structural stability of KTi2(PO4)3/C, the full battery achieves a high capacity retention of 96.7% over 30 000 cycles, excellent rate performance with full charge and discharge in 1 minute, and a high energy density of 47.3 W h kg−1. Demonstration of the performance of this AFKIB system expands the avenues of exploration for large-scale energy storage.

Persistent scatterer (PS) interferometry (PSI) has the ability to achieve submeter-scale digital elevation model and millimeter-scale deformation. However, it is difficult to maintain good performance under long baseline and large phase gradient. In this article, we develop a network optimized ridge estimator for two-tier network PSI. Such a method can increase parameter estimation robustness and spatial continuity in single-prime mode and urban build environments. First, we construct an optimized first-tier network by outlier detection and subsets network construction. On this basis, we utilize the ridge estimator as a substitute for the weighted least squares (WLS) estimator to improve the estimation accuracy in network adjustment. In the second-tier network, we detect the remaining PSs by constructing local star networks, thus increasing the density of the measurements in the first-tier network. The effectiveness of the proposed method is demonstrated by using the 2016–2018 TerraSAR-X dataset acquired in Shenzhen Metropolis, China. In addition, the stress deformation of two typical buildings, i.e., Shenzhen CITIC Building and Shenzhen Convention and Exhibition Center, are monitored and analyzed.

Some recent studies have shown that the surface and interface play an important role in the assembly and aggregation of amyloid proteins. However, it is unclear how the gas-liquid interface affects the protein assembly at the nanometer scale although the presence of gas-liquid interfaces is very common in in vitro experiments. Nanobubbles have a large specific surface area, which provides a stage for interactions with various proteins and peptides on the nanometer scale. In this work, nanobubbles produced in solution were employed for studying the effects of the gas-liquid interface on the assembly of glucagon proteins. Atomic force microscopy (AFM) studies showed that nanobubble-treated glucagon solution formed fibrils with an apparent height of 4.02 ± 0.71 nm, in contrast to the fibrils formed with a height of 2.14 ± 0.53 nm in the control. Transmission electron microscopy (TEM) results also showed that nanobubbles promoted the assembly of glucagon to form more fibrils. Thioflavin T (ThT) fluorescence and Fourier transform infrared (FTIR) analyses indicated that the nanobubbles induced the change of the glucagon conformation to a β-sheet structure. A mechanism that explains how nanobubbles affect the assembly of glucagon amyloid fibrils was proposed based on the above-mentioned experimental results. Given the fact that there are a considerable amount of nanobubbles existing in protein solutions, our results indicate that nanobubbles should be considered for fully understanding the protein aggregation events in vitro.

Developing high-performance electrocatalysts for urea oxidation reaction (UOR) can not only solve the problem of environmental pollution, but also solve the problem of the energy crisis by producing hydrogen for electrodes. The preparation of porous three-dimensional nanostructures as efficient electrocatalysts has become important work. Here, we developed a novel three-dimensional (3D) nanostructure of NiFe(OH)X nanoparticles/nickel foam with a high active area by a simple electroplating method and a subsequent treatment with ferric ion solution. This structure shows much greater UOR activity than the control sample (Ni/Ni foam) with the potential of 1.395 V (vs. RHE) (with an overpotential of 1.025 V) for driving the current density of 100 mA cm−2 in 1.0 M KOH electrolyte with 0.33 M urea. This work not only provides rapid and large-scale preparation of a three-dimensional nanostructure, but also gives a new way to design and obtain high-performance electrocatalysts.

Mechanically robust polymers are broadly applied engineering materials, in which internal, hidden defects resulting from mechanical, electrical and thermal fatigues are one of the major factors threatening their long-term stability. Self-healing of these defects requires the ability of spontaneous crack closure without manually holding the broken parts together, which is not accessible in mechanically robust polymers with previous approaches. Here, we report a self-healing polymer that can be reversibly switched between the glassy state and the high-elastic state, as enabled by the coexistence of reversible and permanent crosslinking sites in the synthesized dynamic crosslinker. This design allows for complete repair of internal defects for multiple times while maintaining the dimensional stability of mechanically robust polymers during the healing process. In addition, this self-healing material is readily prepared by curing the commercially available epoxy monomer with the synthesized dynamic crosslinker, which endows this approach with great potential for industrial applications.

International audience; Water-soluble thermoresponsive polymers present either upper critical solution temperature (UCST) or lower critical solution temperature (LCST) depending on the location of their miscibility range with water at high temperatures or at low temperatures. Compared with LCST polymers, the water-soluble UCST polymers are still less explored until now. In this work three copolymers of P(AAm-co-GAA) were synthesized by copolymerizing two acrylamide monomers, acrylamide (AAm) and acrylamide functionalized with natural glycyrrhetinic acid (GAA), using reversible addition-fragmentation chain transfer (RAFT) polymerization. These copolymers exhibited the typical UCST thermoresponsive behavior, and their phase transition temperatures could be easily tuned to around 37 C for potential biological applications. Moreover, the UCST of P(AAm-co-GAA) can be adjusted not only by the content of glycyrrhetinic acid (GA) and polymer concentrations, but also by the host-guest interactions between GA and cyclodextrins (β-and g-CD). The suitable value of UCST and the biocompatible nature of GA and CDs may endow these copolymers with practical applications in biomedical chemistry

International audience; Polydiacetylenes (PDA) can undergo a blue-to-red color transition in response to external stimuli because of the extensive delocalized p-electron networks and intrinsic conformational restrictions, which make PDA particularly attractive building blocks for stimuli-responsive materials. In this work, a blue chiral C4-MOP/PDA gel was fabricated successfully by UV irradiating a white supramolecular gel that was assembled from a triterpenoid-derived gelator (C4-MOP) and a diacetylene monomer (PCDA). This photopolymerization was completed within 5 min with the generation of the new negative Cotton effect at 657 nm in the visible blue light region, which strongly revealed the transmission, amplification and visualization of molecular chirality during this gelation and the photopolymerization process. Notably, the nanotubular microstructures of the white gel C4-MOP/PCDA that curled from twisted ribbons barely changed after polymerization into C4-MOP/PDA. In addition, because C4-MOP/PDA contained an alternating ene-acetylene conjugated structure, it exhibited multiple color transitions to external stimuli including temperature, organic solvent, and mechanical force. This work provides chiral polydiacetylene assemblies by using natural triterpenoid gelators, and may open new developments in the design of smart responsive chiral PDA materials.

In order to reduce the immunoreactivity of sarcoplasmic calcium-binding protein (SCP), site-directed mutations were used to replace key amino acids in the conformational epitopes and calcium-binding sites. The mutant SCPs (mSCPs) were expressed in Escherichia coli, and their immunoreactivities were analyzed using iELISA and basophil activation assays. Furthermore, the structural changes of mSCPs were determined from the circular dichroism spectra. The iELISA results showed that mSCPs could effectively inhibit the binding of wild-type SCP (wtSCP) to sensitive serum, with inhibition rates that reached 90%. Moreover, mSCPs could downregulate the expression levels of CD63 and CD203c on the basophil surface. Compared with wtSCP, the peak values were significantly changed, and the calcium binding ability was impaired, which explained the decline in immunoreactivities of the mSCPs. All of the data confirmed that this approach was effective in reducing the immunoreactivity of SCP and could be applied to other shellfish allergens.

In this article, we have developed a new sequential sampling scheme, called the double-sequential sampling scheme, in which sampling is proceeded k-at-a-time ( k ≥ 2 ) part of way, and then one-at-...

Lateral flow immunoassay (LFIA), as a prominent point-of-care (POC) test platform, has been extensively adopted for rapid, on-site, and facile diagnosis of pathogen infections and disease biomarkers. Exploring novel structured optical labels of LFIA with amplified signal and complementary detection modes favors the sensitive and flexible POC diagnosis. Here, bimodal labels with both colorimetric and fluorescent readout were fabricated via a layered sequential assembly strategy based on affinity templates and hydrophobic metal-containing nanounits. High-quality colorimetric and fluorescent nanoparticles were densely incorporated into the colloidal supports and confined in separated regions, without interfering with each other. The hierarchical integration of gold nanoparticles and quantum dots with high loading density and good optical preservation realized dual readout and amplified signals from the assemblies of individual single nanoparticles. The "all-in-one" optical labels allowed both colorimetric and fluorescent detection of cystatin C (Cys C) after surface conjugation with antibodies. The LFIA strips revealed noninterfering dual signals for both visual inspection and quantitative detection of Cys C via the naked eye and portable devices, respectively. The limits of detection by colorimetric and fluorescent modes were 0.61 and 0.24 ng mL-1, respectively. The novel LFIA platform demonstrated sensitive, specific, and reproducible POC testing of biomarkers with flexible detection modes and was reliable for clinical diagnosis.

The flow in a multistage axial compressor is highly unsteady, three-dimensional and turbulent. The interaction between compressor blade rows results in rotor/stator wake unsteadiness, which is not typically considered in the computational fluid dynamics (CFD) models. To gain depth and insight into the inner flow mechanism in multistage compressors, specifically the wake variability driven by the rotor/stator and stator/stator interactions, a compound total-pressure pneumatic probe with both high and low response-frequency were designed and manufactured. Unsteady rotor and stator wake measurements between blade rows for the third stage were carried out with this probe installing on a 3-DOF displacement mechanism, to deepen the knowledge of unsteady interactions in the embedded stages of a four-stage low-speed axial compressor. By performing frequency spectrum analysis and ensemble-average methods, higher spectral magnitude of the blade passing frequency (fBPF) and higher root mean square values of total pressure (PtRMS) at both sides of the stator wake region caused by the shedding of upstream boundary layer are revealed. In addition, the high-order harmonics are strengthened by the stator/stator interactions, especially near the blade tip. The individual contributions of rotor geometry variations/interactions of the upstream rotor wakes and the effects of downstream stator potential modulation to the wake variations can be understood.

Cyclodextrin (CD)-based polyrotaxanes (PRs) and polypseudorotaxanes (PPRs) have attracted considerable attention due to their unique topological structures and functions. However, limited by the simple chemical structures and the single functionalization of guest polymer units like poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG), to date the construction of CD-based PRs and PPRs with precisely controllable supramacromolecular structures is fairly rare. In this work, two kinds of molecular necklace-like PPRs with CD-triterpenoid pairs were prepared via the size-dictated construction, where the threaded guest polymer was a natural product-tailored polyurethane (PU-PEG-GA) with the alternating structure of triterpenoid and PEG segments via a simple step-growth polymerization. Taking advantage of the differentiation in host-guest interactions between β/γ-CD and triterpenoid pairs, β-CD simultaneously located on both PEG segments and triterpenoid units in PU-PEG-GA, while γ-CD selectively recognized triterpenoid units. Consequently, the assembly morphology of PU-PEG-GA was adjusted hierarchically from micelles to worms and vesicles upon addition of β-CD, whereas they gradually collapsed to disappear in the presence of γ-CD. Our biocompatible PPRs with precisely controllable supramacromolecular structures may lead to the exploration on understanding and simulating macromolecular recognition using natural products.