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In the present work a new thermal conductivity model is developed for two-phase composite materials, which are consisted of a continuous matrix and dispersed 3D-particles separated from each other by the matrix as a function of grain size and volume ratio of the dispersed particles at different temperatures. The model is applied to reproduce experimental thermal conductivity values of cemented carbide systems WC-Co and WC-Ag. Good agreement was found between measured thermal conductivity data originating from both this work and recent literature and the calculated ones only using semi-empirical parameters for the interfacial thermal resistance (ITR) values at WC/Co, WC/Ag and WC/WC interfaces as a function of temperature. Additionally, the temperature and grain size dependence of the thermal conductivity for WC is established for the first time. The model works well for the case when the matrix (Ag) has a higher thermal conductivity compared to that of the WC particles and also for the case when the matrix (Co) has a lower thermal conductivity compared to that of the WC particles. The new model forms a physically sound basis for further development / materials design of cemented carbides and particle-reinforced composite materials.

Microplastics (MPs) are ubiquitous in the environment and are infiltrating the food chain, causing potential risks to living beings. However, current methods of MP removal from an aqueous environme...

Seed germination is the beginning of a new lifecycle, and involves many complex physiological and biochemical reactions including seed reserve mobilization in the endosperm and nutrient transport and reuse in the embryo. Although glutelin is a dominant storage protein in rice, its contribution to seed germination and its regulatory mechanisms are mostly unknown. Gibberellin (GA) and brassinosteroid (BR), two major growth-promoting phytohormones, also play positive roles in controlling seed germination. However, how GA and BR interact and coordinate seed germination and facilitate glutelin mobilization remains unclear. In the present study, biochemical and physiological analyses of seed germination indicated that both GA and BR promote seed germination and post-germination growth. Exogenous application of GA restored germination defects caused by BR deficiency or insensitivity. Proteomic and qRT-PCR results showed that the expression of several glutelin proteins and their encoding genes was induced by BR and GA in the embryo. Expression assays suggested that the increased accumulation of glutelin protein in the embryo was due to the accelerated degradation of glutelin by a cysteine proteinase (REP-1) in the endosperm. The breakdown of glutelin in the endosperm showed a strict positive correspondence with the length of the shoot. The GluA2 mutation led to reduced degradation rate of glutelin and defects in seed germination, and the promotion effect of GA on seed germination was weakened in the glua2 mutant. In vitro culture assay of rice embryos showed that glutelin mobilization functioned downstream of the GA and BR pathways to promote shoot elongation. These findings suggest a mechanism that mediates crosstalk between BR and GA in co-regulating rice seed germination and embryo growth.

The phase equilibria and thermodynamic properties of the U–Nb system were investigated through experiments and thermodynamic modeling. In the experiments, a series of samples with different content of Nb were prepared by arc melting. The Nb content covers the entire composition range of the U–Nb binary system. After solidification, the samples were annealed and then analyzed by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, differential scanning calorimeter and neutron diffraction. The equilibrium phases, including γ1 (U-rich bcc), αU, and γ2 (U-depleted bcc), were determined in detail from the experimental characterization. The occurrence of the invariant reaction γ1→ αU + γ2 was confirmed, and the reaction temperature and composition were accurately identified. Moreover, the experimental findings clarify the dispute between the Dwight and Terekhov theories regarding the phase region (i.e., whether the phase region is αU + γ1 or βU + γ2). Furthermore, the U–Nb phase diagram was reassessed by incorporating the present experimental data and previously published reliable experimental data from the literature. A set of self-consistent thermodynamic parameters were developed using CALPHAD (Calculation of phase diagrams), and the calculations reasonably agree with the experimental observations.

Soft object manipulation has recently gained popularity within the robotics community due to its potential applications in many economically important areas. Although great progress has been recently achieved in these types of tasks, most state-of-the-art methods are case-specific; They can only be used to perform a single deformation task (e.g. bending), as their shape representation algorithms typically rely on "hard-coded" features. In this paper, we present LaSeSOM, a new feedback latent representation framework for semantic soft object manipulation. Our new method introduces internal latent representation layers between low-level geometric feature extraction and high-level semantic shape analysis; This allows the identification of each compressed semantic function and the formation of a valid shape classifier from different feature extraction levels. The proposed latent framework makes soft object representation more generic (independent from the object's geometry and its mechanical properties) and scalable (it can work with 1D/2D/3D tasks). Its high-level semantic layer enables to perform (quasi) shape planning tasks with soft objects, a valuable and underexplored capability in many soft manipulation tasks. To validate this new methodology, we report a detailed experimental study with robotic manipulators., Comment: 12 pages, 14 figures, 2 tables

In this study, a new Fe-6Mn-4Al-0.4C high strength medium manganese hot rolled steel sheet was designed. The influence mechanism of the intercritical annealing (IA) temperature on microstructure evolution and mechanical properties of experimental steel were studied by SEM and XRD. The experimental steel was held for 30 minutes at 640°C, 680°C, 720°C, 760°C, 800°C, respectively. When the annealing temperature was 640°C, cementite particles precipitated between the austenite and ferrite phase boundary. As the annealing temperature increased, the cementite gradually dissolved and disappeared, the fraction of lamellar austenite increased significantly. When the annealing temperature is 800°C, the coarse equiaxed austenite and ferrite appeared. The yield strength (YS) decreased, the product of strength and elongation (PSE) and total elongation (TE) both increased first and then decreased, while the ultimate tensile strength (UTS) showed the opposite trend. The experimental steel exhibited excellent comprehensive mechanical properties after held at 760°C for 30 min. The UTS was 870 MPa, the YS was 703 MPa, and the TE was 77 %, the PSE was 67 GPa·%.

An efficient and modular strategy was used to obtain enaminones with a wide range of functional groups via a four-component sequential reaction. This reaction proceeded under mild conditions without a catalyst in one pot. Furthermore, the products could be transformed into thiadiazoles.

To develop high-quality refractory metal targets, pure W and W/Re alloys (with Re contents of 1, 5 and 10 mass%) were fabricated via mechanical mixing, press forming and vacuum sintering. Properties such as relative density, grain size and orientation, and magnetron sputtering characteristics were investigated in the W/Re alloys. With increasing Re content, both the relative density and purity of the W-Re alloys increased, while the grain size decreased. The sizes of the grains in the W/10 mass% Re alloy target were mainly between 10 and 40 μm. The results of electron backscatter diffraction (EBSD) indicated that the grains in the W/Re alloys were randomly distributed and did not have a preferred orientation. The percentage of small-angle grain boundaries (

Ionic liquids (ILs) have shown excellent performance in the separation of binary azeotropes through extractive distillation [1]. But the role of the ionic liquid in azeotropic system is not well understood. In this paper, COSMO-RS model was applied to screen an appropriate IL to separate the binary azeotrope of ethyl acetate (EA) and ethanol and 1-octyl-3-methylimidazolium tetrafluoroborate ([OMIM][BF4]) was selected. The Quantum Mechanics (QM) calculations and molecular dynamics (MD) simulation are performed to study the interactions between the solvent molecules and [OMIM][BF4], in order to investigate the separation mechanism at the molecular level. The nature of the interactions is studied through the reduced density gradient (RDG) function and quantum theory of Atom in Molecule (QTAIM). Hydrogen bonds and van der Waals interactions are the key interactions in the complexes. The results of MD simulations indicate that the introduction of ILs has a prominent effect on the interaction between the solvent molecules, especially on reducing the number of hydrogen bonds among the solvent molecules. The radial distribution function (RDF) reveals that the interaction between the cation and solvent molecules will increase while the concentration of ILs increases. This paper provides important information for understanding the role of ILs in the separation of the azeotropic system, which is valuable to the development of new entrainers. National Key R&D Program of China (2018YFB0604900); National Natural Science Foundation of China (No. 21878219); Natural Sciences and Engineering Research Council (NSERC) of Canada (RGPIN-4903-2014); China Scholarship Council (No. 201500090106)

This paper reports a 3-dimentional (3D) pressure sensor based on surface acoustic wave (SAW) resonators. The SAW resonators were designed and fabricated on 128°Y-X LiNbO3 substrate using the MEMS technology. The pressure sensing structure was 3D-printed using polyactic acid plastic, and two SAW resonators were integrated in the 3D-printed chamber structure for both temperature and pressure sensing. The SAW-based gas pressure sensors demonstrate a sensitivity of 589 ppm/MPa at the pressure range of 100-600 kPa and temperature of 40 °C.

Helical supramolecular architectures play important structural and functional roles in biological systems. Although their occurrence is widely perceived to correlate to fundamental chiral units including l-amino acids and d-sugars, the detailed relationship between molecular and supramolecular handedness is still unclear. At the same time, although achiral units are practically always in close proximity to chiral ones by covalent linkage along a polymeric chain, their effect on supramolecular handedness has received relatively less attention. Here, we designed a set of short amphiphilic peptides, in which an achiral glycine residue was incorporated at the interface between the hydrophobic and hydrophilic segments. We observed that glycine incorporation caused dramatic variations in suprastructural handedness in self-assembled peptide nanofibrils, and the effect of the hydrophilic charged residue at the C-terminus on supramolecular handedness was demolished, leading to chiral truncation. Furthermore, molecular dynamics simulations and quantum chemistry calculations revealed that the unanticipated role of the glycine residue in regulating supramolecular handedness originated from its effect on the conformational preference of single β-strands. Importantly, reduced density gradient analyses on single β-strands indicated that, due to the lack of a side chain in glycine, intricate noncovalent interactions were produced among the neighboring amino acid side chains of the incorporated glycine and its local backbone, resulting in diverse β-strand conformations.

Many reagents as electron sacrificers have been recently investigated to induce decomposition of permanganate (KMnO4) to produce highly reactive intermediate Mn species toward oxidation of organic contaminants; however, this strategy meanwhile causes low KMnO4 utilization efficiency. This study surprisingly found that graphite can mediate direct electron transfer from organics (e.g., sulfamethoxazole (SMX)) to KMnO4, resulting in high KMnO4 utilization efficiency, rather than reductive sites of graphite-induced conversion of KMnO4 to highly reactive intermediate Mn species. The galvanic oxidation process (GOP) and comparative experiments of different organic contaminants prove that the KMnO4/graphite system mainly extracts electrons from organic contaminants via a one-electron pathway instead of a two-electron pathway. More importantly, the KMnO4/graphite system has superior reusability, graphite can keep a long-lasting reactivity, and the KMnO4 utilization efficiency elevates significantly after each cycle of graphite. The transformation of SMX in the KMnO4/graphite system mainly includes self-coupling, hydroxylation, oxidation, and hydrolytic reaction. The work will improve insights into the electron-transfer mechanism and unveil the advantages of efficient KMnO4 utilization in the KMnO4-based technologies in environmental remediation.

The anisotropic ceramic fiber skeleton and its aerogel composite materials have important applications in the fields of high temperature insulation and aerospace. However, the traditional ceramic fiber skeleton has been limited in its application due to the complexity of its preparation process. Here, referencing the traditional papermaking technology, a flexible and recoverable SiO2 fiber skeleton with anisotropic layered structure was prepared through papermaking process and low-temperature sintering (170 °C) technology. Complete heteromorphic skeleton could be prepared by this simple process. On this basis, we impregnated the fiber skeleton with silica aerogel to further improve the composite properties of the pure fiber block. Compared with SiO2 fiber skeleton, the SiO2 aerogel/fiber skeleton composite exhibited lower thermal conductivity (0.023 W/(m·k)), higher compressive strength (2.19 MPa) and excellent high temperature thermal insulation. The recoverable and excellent thermal insulation properties of anisotropic layered composite materials provide an effective way for the manufacture of low-cost aerogel composite materials. At the same time, it has potential application value in high-temperature thermal insulation materials.

In this paper, we mainly investigate the population dynamics of a general competitive parabolic system including both diffusion and advection. For such a class of systems, we provide an efficient way to determine the global dynamics by values of competition coefficients b and c. Precisely, a clear picture on the local dynamics of the two semi-trivial steady states is firstly given in terms of critical competition values by the monotonicity of the principal eigenvalue, and then a further determination on the global dynamics in different regions on the b-c plane is presented by establishing the uniqueness or non-existence of coexistence steady states. Our results extend largely those in a previous work [32] by removing two conditions (see ( A 1 ) and ( A 2 ) below).

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.

Developing high-efficiency, stable and non-precious electrocatalysts for oxygen reduction reaction (ORR) is highly important for energy conversion and storage. Single atom catalysts (SACs) show good potential in enhancing ORR, however, the specifical control over the coordination surroundings around single metal center to intrinsically modify the electron structure is still a great challenge. Herein, we demonstrate that a 3D hybrid MOF composed of cobalt doped ZIF-L and ZIF-8, featuring star morphology with six equal branches, can be used as an advanced precursor for making the Co SACs for greatly boosted ORR. The as-synthesized CoSA-N-C exhibits excellent ORR activity with E1/2 of 0.891 V in alkaline medium, outperforming the commercial Pt/C by 39 mV. Moreover, the E1/2 of CoSA-N-C (0.790 V) is merely 15 mV, less than that of Pt/C (0.805 V) in acid medium, which is among the best in the reported state-of-the-art SACs. DFT calculations demonstrate that the enhanced ORR performance is assigned to the formation of atomically isolated cobalt atom coordinated three N atoms and one C atom, which is easier to decrease the free energy of rate determining step and accelerate the ORR process than that of traditional cobalt atom coordinated four N atoms. In addition, a primary Zn-air battery with CoSA-N-C cathode reveals a maximum power density of 92.2 mW cm−2 at 120.0 mA cm−2, far higher than that of commercial catalysts (74.2 mW cm−2 at 110.0 mA cm−2).

In this study, activated biochar prepared using Taihu blue algae was adopted to facilitate cathodic hydrogenotrophic denitrification in bioelectrochemical system (BES). It was found that addition of algal biochar (ABC)-800N (treated with nitric acid) at biocathode reached the highest nitrate removal constant (21.79), while the control reached only 6.94. Besides, activity of nitrous oxide reductase attained 5.16 U/L for the control in day 7, while group ABC-800N reached 16.06 U/L by then. Importantly, chronoamperometry (CA) detect indicated an electron exchange capacity for group ABC-800N as 872.68 μmol e−/gBC, compared to 162.81 μmol e−/gBC for the control. Through chronocoulomb (CC), better charge/discharge stability can be concluded in BES reactor using ABC-800N. Therefore, activated biochar could be implemented to enhance denitrification process at biocathode in BES.

Summary Photocatalytic co-production of high value-added multicarbon compounds and hydrogen from renewable bioethanol is an environmental and long-term approach to industrial activities and remains a great challenge because of the difficulty in bioethanol dehydrogenation. Guided by first-principle simulation, we first synthesized a partially reduced Pd–P3 single atom (PdPSA) on CdS nanorods with an unoccupied hybrid state of Pd 4d and P 3p via both metal-support interaction effect and Pd–P coordination effect. This unique electronic structure of PdPSA is totally different from highly reduced S-coordinated Pd single atoms or nanoparticles and allows PdPSA-CdS to exhibit a visible-light photocatalytic activity of 35.1 mmol g−1 h−1 for the co-production of high-value-added 1,1-diethoxyethane and H2 with a selectivity of 100%. Mechanism studies revealed that the unoccupied hybrid states of Pd 4d and P 3p in PdPSA not only greatly promoted the dehydrogenation of ethanol but also promised PdPSA with a high H2-production activity.

A mild and environmentally friendly method to synthesize half-sandwich ruthenium complexes through the Wittig reaction between an aldehyde-tagged half-sandwich ruthenium complex and phosphorus ylide mechanochemically is reported herein. The mechanochemical synthesis of valuable half-sandwich ruthenium complexes resulted in a fast reaction, good yield with simple workup, and the avoidance of harsh reaction conditions and organic solvents. The synthesized half-sandwich ruthenium complexes exhibited high catalytic activity for transfer hydrogenation of ketones using 2-propanol as the hydrogen source and solvent. Density functional theory was carried out to propose a mechanism for the transfer hydrogenation process. The modeling suggests the importance of the labile p-cymene ligand in modulating the reactivity of the catalyst.

The Indus Fan derives sediment from the western Himalaya and Karakoram. Sediment from International Ocean Discovery Program drill sites in the eastern part of the fan coupled with data from an industrial well near the river mouth allow the weathering history of the region since ca. 16 Ma to be reconstructed. Clay minerals, bulk sediment geochemistry, and magnetic susceptibility were used to constrain degrees of chemical alteration. Diffuse reflectance spectroscopy was used to measure the abundance of moisture-sensitive minerals hematite and goethite. Indus Fan sediment is more weathered than Bengal Fan material, probably reflecting slow transport, despite the drier climate, which slows chemical weathering rates. Some chemical weathering proxies, such as K/Si or kaolinite/(illite + chlorite), show no temporal evolution, but illite crystallinity and the chemical index of alteration do have statistically measurable decreases over long time periods. Using these proxies, we suggest that sediment alteration was moderate and then increased from 13 to 11 Ma, remained high until 9 Ma, and then reduced from that time until 6 Ma in the context of reduced physical erosion during a time of increasing aridity as tracked by hematite/goethite values. The poorly defined reducing trend in weathering intensity is not clearly linked to global cooling and at least partly reflects regional climate change. Since 6 Ma, weathering has been weak but variable since a final reduction in alteration state after 3.5 Ma that correlates with the onset of Northern Hemispheric glaciation. Reduced or stable chemical weathering at a time of falling sedimentation rates is not consistent with models for Cenozoic global climate change that invoke greater Himalayan weathering fluxes drawing down atmospheric CO2 but are in accord with the idea of greater surface reactivity to weathering.

Covalent organic frameworks (COFs) have great application potentials in photocatalytic water treatment. By using p-phenylenediamine with different numbers and locations of heterocyclic nitrogen atoms as a precursor, five types of COFs with different nitrogen positions were synthesized. We found that Cr(VI) photoreduction,Escherichia coli inactivation, and paracetamol degradation by COFs were heterocyclic nitrogen location-dependent. Particularly, the photocatalytic performance for all three tested pollutants by five types of COFs followed the order of the best performance for COF-PDZ with two ortho position heterocyclic N atoms, medium for COF-PMD with two meta position heterocyclic N atoms, and COF-PZ with two para position heterocyclic N atoms, and COF-PD with a single heterocyclic N atom, the worst performance for COF-1 without a heterocyclic N atom. Compared to the other COFs, COF-PDZ contained improved quantum efficiency and thus enhanced generation of electrons. The lower energy barriers and larger energy gaps of COF-PDZ contributed to its improved quantum efficiencies. The stronger affinity to Cr(VI) with lower adsorption energy of COF-PDZ also contributed to its excellent Cr(VI) reduction performance. By transferring into a more stable keto form, COF-PDZ showed great stability through five regeneration and reuse cycles. Overall, this study provided an insight into the synthesis of high-performance structure-dependent COF-based photocatalysts.

The peptide quantitative structure-activity relationship (QSAR), also known as the quantitative sequence-activity model (QSAM), has attracted much attention in the bio- and chemoinformatics communities and is a well developed computational peptidology strategy to statistically correlate the sequence/structure and activity/property relationships of functional peptides. Amino acid descriptors (AADs) are one of the most widely used methods to characterize peptide structures by decomposing the peptide into its residue building blocks and sequentially parametrizing each building block with a vector of amino acid principal properties. Considering that various AADs have been proposed over the past decades and new AADs are still emerging today, we herein query the following: is it necessary to develop so many AADs and do we need to continuously develop more new AADs? In this study, we exhaustively collect 80 published AADs and comprehensively evaluate their modeling performance (including fitting ability, internal stability, and predictive power) on 8 QSAR-oriented peptide sample sets (QPSs) by employing 2 sophisticated machine learning methods (MLMs), totally building and systematically comparing 1280 (80 AADs × 8 QPSs × 2 MLMs) peptide QSAR models. The following is revealed: (i) None of the AADs can work best on all or most peptide sets; an AAD usually performs well for some peptides but badly for others. (ii) Modeling performance is primarily determined by the peptide samples and then the MLMs used, while AADs have only a moderate influence on the performance. (iii) There is no essential difference between the modeling performances of different AAD types (physiochemical, topological, 3D-structural, etc.). (iv) Two random descriptors, which are separately generated randomly in standard normal distribution N(0, 1) and uniform distribution U(-1, +1), do not perform significantly worse than these carefully developed AADs. (v) A secondary descriptor, which carries major information involved in the 80 (primary) AADs, does not perform significantly better than these AADs. Overall, we conclude that since there are various AADs available to date and they already cover numerous amino acid properties, further development of new AADs is not an essential choice to improve peptide QSAR modeling; the traditional AAD methodology is believed to have almost reached the theoretical limit nowadays. In addition, the AADs are more likely to be a vector symbol but not informative data; they are utilized to mark and distinguish the 20 amino acids but do not really bring much original property information to these amino acids.

Cracking and low thickness are major obstacles to the high corrosion performance of conversion coating on magnesium alloy. In this work, the ratio of total acidity to pH (TA/pH) was applied as an indicator, and new principles regarding the design of conversion bath were proposed. The treatment bath should be composed of species that can be categorized into two groups: the first group of species that react with Mg substrate to increase the local pH at the interface; the second group that precipitate and contributes to the growth of coating. The species belong to second group exists in a supersaturated state and its precipitation process is almost independent on the reactions of the species in first group. By this way, a thick and crack-free two-layered conversion coating is obtained. Moreover, the nature of the adjustment of TA/pH and the roles of the oxidizing agent and catalyst were discussed.

Drilling rigs for deep seabed shallow strata are commonly used to explore ocean cobalt-rich crust resources and other fields. This paper mainly presents the structure and mechanism of a mobile drilling rig for use in acquiring seafloor cores that are up to 1.5 m in length. The software Simcenter Amesim is used to establish the mobile drilling rig's hydraulic propulsion system model, which is the basis and a core part of the rig. Moreover, closed-loop and PID (proportion-integral-differential) control methods are separately used to control the hydraulic propulsion system for simulation analysis. Comparison of the simulation results shows that the PID control method is more convincing in verifying the design rationality of the hydraulic propulsion system. In the simulation of the PID-controlled hydraulic propulsion system, the co-simulation technology of Simcenter Amesim and MATLAB/Simulink not only establishes the hydraulic and control models but also determines the relevant simulation parameters, thereby helping improve system simulation efficiency. In its verification deployment in the South China Sea, the mobile drilling rig has been operated many times at different depths, and some cores have been successfully obtained. It was also used during the 55th Voyage of China Oceanic Scientific Expedition, which was supported by the China Ocean Mineral Resources R&D Association. Several sites were explored, and a large number of cobalt-rich crust cores were obtained. Theory and sea trials are explained to support further research on the survey of abyssal resources.

In order to obtain high-quality microbial samples from the hadal zone, which has a depth of over 6,000 m, a full-ocean-depth sampler with the function of in-situ filtration and preservation was developed. A flow pump and several membrane filters were used for in-situ filtration under the sea. With a multistage filtering structure, the microbes can be initially screened according to their sizes. To avoid the degradation of microbial ribonucleic acid (RNA), a special structure was designed to inject the RNAlater solution into the samples immediately after the filtration. The sampler was tested in our laboratory and deployed during Mariana TS-15 in 2019. It was installed on a hadal lander of Shanghai Ocean University and deployed at MBR02 (11.371°N, 142.587°E, 10,931 m) in the Mariana Trench. A total of 20 L of in-situ seawater was filtered, and membranes with pore sizes of 3 and 0.2 μm were preserved. The study is expected to provide important support for the establishment of a hadal microbial gene pool.

The development of efficient and stable electrode materials is a cutting-edge method to improve electrocatalytic activity. The way of combination biomass-derived porous carbon and metal oxides is considered to be an effective strategy to improve the redox reaction. In this study, we selected tea as a biomass carbon source and synthesized 3D structure of tea porous carbon (TPC) using a template-free method. TiO2/TPC composite material was successfully prepared through one-step simple hydrothermal reaction without destroying the pore structure. The degradation effect of phenol and the yield of ·OH were used as the evaluation criteria for the electrocatalytic performance of composites. The results show that TiO2/TPC-1:2 (20) has an excellent phenol degradation effect (97.54%). The good degradation effect is based on the reasonable design of the structure of composite materials. This effective preparation strategy of composite maximizes the advantages of the pore structure of the material itself and creates a large number of good channels for electron transport. At the same time, the load of metal oxide can effectively promote more catalytic active sites, which has a certain significance for the preparation of porous carbon or porous carbon matrix composite materials.

Furfural is regarded as one of the most promising bio-based feedstocks in the bio-refinery industry. Selective hydrogenation of the carbonyl bond in furfural plays a vital role in its conversion to downstream products. Electrochemical hydrogenation (ECH) method provides a green and sustainable way for this reaction. Yet, it still suffers from harsh pH conditions and low selectivity for highly reduced products, such as 2-methylfuran. In this study, high faradaic efficiencies of over 90% for furfuryl alcohol and 60% for 2-methylfuran were obtained in a near-neutral environment (pH = 5) at −0.75 V and −0.90 V vs. the reversible hydrogen electrode, respectively. The key to this success is the integration of single atom copper active sites and the oxophilic phosphorus dopants in a single catalyst. Single atom Cu sites are found to be the active centers for this reaction and decreasing the size of Cu sites to a single atom enhances the efficiencies of the ECH reactions by suppressing the competing hydrogen evolution reaction. Phosphorus doping facilitates furfural hydrogenation to 2-methylfuran via a sequential two-step reduction process. This study opens up possibilities for the selective electrochemical hydrogenation of furfural to 2-methylfuran under mild conditions.

Ni/TiO2 as a classic system has been widely studied in the traditional catalysis field including the water-gas shift reaction and selective oxidation/hydrogenation. However, in terms of the electrocatalytic hydrogen evolution reaction (HER), there is still a lack of systematic research on the actual synergistic promotion effect on the performance, and the influence of the host material on the electronic interaction between Ni and TiO2 is still unclear. Herein, we synthesized a series of Ni/TiO2 composites with different forms and tested the relevant HER performance. The results show that Ni/TiO2 exhibits much better HER performance than pure Ni and there is one type of electronic interaction between Ni and TiO2 in the composite with different forms, that is, electrons transfer from Ni to TiO2. However, the interaction strength is host dependent, and the composite with Ni as the host displays the strongest interaction, and therefore the best HER performance (46 mV at 10 mA cm−2).

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an etiological agent of the current rapidly growing outbreak of coronavirus disease (COVID-19), which is straining health systems around the world. Disrupting the intermolecular association of SARS-CoV-2 spike glycoprotein (S protein) with its cell surface receptor human angiotensin-converting enzyme 2 (hACE2) has been recognized as a promising therapeutic strategy against COVID-19. The association is a typical peptide-mediated interaction, where the hACE adopts an α1-helix, which can form a two-helix bundle with the α2-helix, to pack against a flat pocket on the S protein surface. Here, we demonstrate that the protein context of full-length hACE plays an essential role in supporting the hACE2 α1-helix recognition by viral S protein. Energetic analysis reveals that the α1-helical peptide (αHP) and also the two-helix bundle peptide (tBP) cannot bind effectively to S protein when they are split from the hACE protein. The context contributes moderately and considerably to the direct readout (DR) and indirect readout (IR) of peptide recognition, respectively. Dynamics simulation suggests that the two free peptides exhibit a large intrinsic disorder without the support of protein context, which would incur a considerable entropy penalty upon binding to S protein. To restore the IR effect lost by splitting peptides from hACE, we herein propose employing hydrocarbon stapling and cyclization strategies to constrain the free αHP and tBP peptides into their native ordered conformations, respectively. The stapling and cyclization are carefully designed in order to avoid influencing the peptide DR effect, which has been demonstrated to improve the peptide binding affinity (but not specificity) to S protein. The stapling/cyclization-imposed conformational constraint can effectively minimize the unfavorable IR effect (i) by reducing the peptide flexibility and entropy cost upon their binding to S protein, and (ii) by helping peptide pre-folding into their native state to facilitate the conformational selection by S protein.

Background Plaque rupture (PR) and plaque erosion (PE) are the two major pathological phenotypes in acute coronary syndrome. Since microRNAs have been found to be involved in the mechanisms of PR and PE, we investigated the diagnostic utility of microRNAs in differentiating between patients with PR and patients with PE. Methods MicroRNA sequencing was performed on plasma from 21 patients with PR, 20 patients with PE and 17 healthy control subjects (HCs). 24 miRNAs were selected for validation in 20 PR patients and 20 PE patients and 8 miRNAs were further validated in an independent replication cohort (82 patients with PR, 84 patients with PE and 59 HCs) by applying quantitative real-time polymerase chain reaction. Then we analyzed pathways associated with significant miRNAs in PR. Results MiR-744-3p, miR-324-3p and miR-330-3p were significantly upregulated in the PR group compared with the PE group (Log10miR-744-3p: 0.26[‐−0.28—1.57] versus −0.41[−0.83—-0.03], padj Conclusion A set of circulating microRNAs (miR-744-3p, miR-330-3p, and miR-324-3p) is associated with PR and has clinical utility as a diagnostic marker for distinguishing the plaque phenotype in STEMI patients.

Atomically thin two-dimensional (2D) van der Waals materials have exhibited many exotic layer-dependent physical properties including electronic structure, magnetic order, etc. Here, we report a striking even–odd layer dependent oscillation in the ferroelectric polarization of 2H-stacked few-layer α-In2Se3 nanoflakes. As characterized by piezoresponse force microscopy (PFM), when the in-plane (IP) electric polarization of 2H-stacked α-In2Se3 films is electrically aligned, the out-of-plane (OOP) polarization of the odd-layer (OL) samples is obviously larger than that of the even-layer (EL) ones. Similarly, samples with electrically aligned OOP polarization also show even–odd layer dependent IP polarization. Such an even–odd oscillation, as confirmed by the density functional theory calculations, can be attributed to the strong intercorrelation of the IP and OOP electric polarization of the α-In2Se3 monolayers and the special 2H-stacking structure of a 180 degree IP rotation with respect to the adjacent layers. Moreover, a negative differential resistance, interestingly, is induced by the polarization flip with a small coercive field of ∼1.625 kV cm−1, and its peak-to-valley ratio can be tuned up to ∼7 by the gate. This work demonstrates that the delicate stacking geometry of multilayer α-In2Se3 can bring an interesting even–odd ferroelectric effect, enriching the layer-dependent physical properties of the 2D materials family.

Multimode microwave remote sensors are a new type of radar system that operates in SAR (synthetic aperture radar), scatterometer, altimeter, and spectrometer modes in a time-sharing manner according to the current task scheduled on small satellites. High flexibility through mode switching is the outstanding advantage of this new microwave remote sensor. Two or more small satellites operating in different operation modes can be networked to perform observations synchronously to provide excellent remote sensing performance. This paper focuses on a method to determine the radar parameters of the scatterometer mode since the frequency band and the platform height of this new of kind sensor are determined according to the requirement of the SAR mode, and their values are evidently different from the values of current scatterometers in orbit. The proposed method systematically presents the complete steps and related formulae of the radar parameter design of scatterometers and determines the signal bandwidth by optimization. A system simulation method of the scatterometer mode is further studied to determine the wind field inversion error and thus evaluate the rationality of the parameter design results. In contrast to the existing methods, which directly add noise to the backscatter coefficients, our method simulates the noisy echo of the scatterometer and then retrieves the wind field by estimated backscatter coefficients from the noisy echo. The performed simulation shows that, by using the designed system parameters, the multimode microwave remote sensor obtains wind field inversion accuracy, resolution and swath width comparable to those of the HY-2 satellite and the QuikSCAT satellite.

Single-parent expression (SPE) is defined as gene expression in only one of the two parents. SPE can arise from differential expression between parental alleles, termed non-presence/absence (non-PAV) SPE, or from the physical absence of a gene in one parent, termed PAV SPE. We used transcriptome data of diverse Zea mays (maize) inbreds and hybrids, including 401 samples from five different tissues, to test for differences between these types of SPE genes. Although commonly observed, SPE is highly genotype and tissue specific. A positive correlation was observed between the genetic distance of the two inbred parents and the number of SPE genes identified. Regulatory analysis showed that PAV SPE and non-PAV SPE genes are mainly regulated by cis effects, with a small fraction under trans regulation. Polymorphic transposable element insertions in promoter sequences contributed to the high level of cis regulation for PAV SPE and non-PAV SPE genes. PAV SPE genes were more frequently expressed in hybrids than non-PAV SPE genes. The expression of parentally silent alleles in hybrids of non-PAV SPE genes was relatively rare but occurred in most hybrids. Non-PAV SPE genes with expression of the silent allele in hybrids are more likely to exhibit above high parent expression level than hybrids that do not express the silent allele, leading to non-additive expression. This study provides a comprehensive understanding of the nature of non-PAV SPE and PAV SPE genes and their roles in gene expression complementation in maize hybrids.

A grand challenge of biological chemical production is the competition between synthetic circuits and host genes for limited cellular resources. Quorum sensing (QS)-based dynamic pathway regulations provide a pathway-independent way to rebalance metabolic flux over the course of the fermentation. Most cases, however, these pathway-independent strategies only have capacity for a single QS circuit functional in one cell. Furthermore, current dynamic regulations mainly provide localized control of metabolic flux. Here, with the aid of engineering synthetic orthogonal quorum-related circuits and global mRNA decay, we report a pathway-independent dynamic resource allocation strategy, which allows us to independently controlling two different phenotypic states to globally redistribute cellular resources toward synthetic circuits. The strategy which could pathway-independently and globally self-regulate two desired cell phenotypes including growth and production phenotypes could totally eliminate the need for human supervision of the entire fermentation., A challenge for biological chemical production is the completion between synthetic circuits and host resources. Here the authors the authors use quorum sensing circuits and global mRNA decay to independently control two phenotypic states.

This report is on studies directed at the nature of magneto-electric (ME) coupling by ferromagnetic resonance (FMR) under an electric field in a coaxial nanofiber of nickel ferrite (NFO) and lead zirconate titanate (PZT). Fibers with ferrite cores and PZT shells were prepared by electrospinning. The core–shell structure of annealed fibers was confirmed by electron- and scanning probe microscopy. For studies on converse ME effects, i.e., the magnetic response of the fibers to an applied electric field, FMR measurements were done on a single fiber with a near-field scanning microwave microscope (NSMM) at 5–10 GHz by obtaining profiles of both amplitude and phase of the complex scattering parameter S11 as a function of bias magnetic field. The strength of the voltage-ME coupling Av was determined from the shift in the resonance field Hr for bias voltage of V = 0–7 V applied to the fiber. The coefficient Av for the NFO core/PZT shell structure was estimated to be − 1.92 kA/Vm (− 24 Oe/V). A model was developed for the converse ME effects in the fibers and the theoretical estimates are in good agreement with the data.

We report here a guest-reaction-induced mitosis-like host transformation from a known Pd4 L2 cage 1 to a conjoined Pd6 L3 twin-cage 2 featuring two separate cavities. The encapsulation of 1-hydroxymethyl-2-naphthol (G1), a known ortho-quinone methide (o-QMs) precursor, within the hydrophobic cavity of cage 1 is found crucial to realize the cage to twin-cage conversion. Confined G1 molecules within the nanocavity undergo self-coupling dimerization reaction to form 2,2'-dihydroxy-1,1'-dinaphthylmethane (G2) which then triggers the cage to twin-cage mitosis. The same conversion also proceeds, in a much faster rate, via the direct templation of G2, confirming the induced-fit transformation mechanism. The structure of the (G2)2 ⊂2 host-guest complex has been established by X-ray crystallographic study, where cis- to trans- conformational switch on one bridging ligand is revealed.

Tannin-immobilized cellulose was prepared by the phenolic reaction of the phenol ring of tannin with the aldehyde group of aldocellulose, where aldocellulose was prepared by the oxidization of cell...

The sluggish kinetics of Fe(Ⅱ) recovery in Fenton/Fenton-like reactions significantly limits the oxidation efficiency. In this study, we for the first time use boron carbide (BC) as a green and stable promotor to enhance the reaction of Fe(Ⅲ)/H2O2 for degradation of diverse organic pollutants. Electron paramagnetic resonance analysis and chemical quenching/capturing experiments demonstrate that hydroxyl radicals (•OH) are the primary reactive species in the BC/Fe(Ⅲ)/H2O2 system. In situ electrochemical analysis indicates that BC remarkably boosts the Fe(Ⅲ)/Fe(Ⅱ) redox cycles, where the adsorbed Fe(Ⅲ) cations were transformed to more active Fe(Ⅲ) species with a higher oxidative potential to react with H2O2 to produce Fe(Ⅱ). Thus, the recovery of Fe(Ⅱ) from Fe(Ⅲ) is facilitated over BC surface, which enhances •OH generation via Fenton reactions. Moreover, BC exhibits outstanding reusability and stability in successive cycles and avoids the secondary pollution caused by conventional organic and metalliferous promotors. Therefore, metal-free BC boosting Fe(Ⅲ)/H2O2 oxidation of organics provides a green and advanced strategy for water decontamination.

Although the factors affecting rural-to-urban migration have been discussed and analyzed in detail, few studies have examined the spatiotemporal dynamic characteristics of rural migrants’ employment and working-cities in the post-immigrate era, which is essential for the citizenization and social integration of new-type urbanization in China. This study uses survey data from rural migration laborers across the eastern, central, and western China to construct a comprehensive labor migration stability index, and compares the determinants of the migration stability of rural labor among cities and industries using Geodetector. The results are as follows: 1) Compared with the midwestern cities, eastern cities have attracted younger and more skilled rural labor, and industries with higher technical content have higher migration stability among rural laborers. 2) Rural laborers more often adapt to changes by changing employment instead of changing working-cities. 3) The individual experiences of rural laborers and urban characteristics have significant impacts on the stability of migration, and family and societal guanxi (Chinese interpersonal relationships) enhance migration stability. 4) A unified labor market and convenient transportation have somewhat slowed industrial transfers and labor backflow. This study enhances our understanding of the roles of industrial transfer and new-type urbanization in shaping the labor geography landscape and provides policy implications for the promotion of people-oriented urbanization.

The potential advantages of using 2D graphene oxide (GO)-based composites stimulating cellular differentiation as well as improve the compressive strength of the scaffolds. The present study investigated the biphasic calcium phosphate (BCp)/polyvinylpyrrolidone (PVp)/Graphene oxide (GO) composite with different GO (w/w) content of 1 wt%, 3 wt%, and 5 wt%. When increasing GO content, the compressive strength of scaffolds increased by 366 ± 37, 387 ± 28, and 558 ± 14 for 1 wt%, 3 wt%, and 5 wt% respectively.The TEM images showed the presence of a homogeneous distribution of BCp nanoparticles onto the graphene oxide surface; also Raman and XRD results confirm the formation of composite scaffolds. Furthermore, in vitro cytocompatibility of the BCp-PVp/GO 5 wt% composites were evaluated by cell adhesion and live/dead analysis using MG-63 cells. The obtained results showed that no adverse effect was witnessed, which evidences the superior bio compatibility nature of the composite scaffold. These results suggested that the BCp-PVp/GO composites could be a promising material for tissue engineering application.

A series of multinuclear lanthanide-covalent organic polyhedra (LnCOPs), including pillar-typed triangular prisms 1-Ln3 and tetrahedra 2-Ln4 (Ln = LaIII, SmIII, EuIII), have been constructed for th...

An environmentally sustainable strategy for the chemoselective heterocyclization of bromoenynes through a transition-metal-free sulfuration/cyclization process is reported. Using inexpensive and sa...

The genomic sequences of crops continue to be produced at a frenetic pace. However, it remains challenging to develop complete annotations of functional genes and regulatory elements in these genomes. Here, we explore the potential to use DNA methylation profiles to develop more complete annotations. Using leaf tissue in maize, we define ∼100,000 unmethylated regions (UMRs) that account for 5.8% of the genome; 33,375 UMRs are found greater than 2 kilobase pairs from genes. UMRs are highly stable in multiple vegetative tissues and they capture the vast majority of accessible chromatin regions from leaf tissue. However, many UMRs are not accessible in leaf (leaf-iUMRs) and these represent a set of genomic regions with potential to become accessible in specific cell types or developmental stages. Leaf-iUMRs often occur near genes that are expressed in other tissues and are enriched for transcription factor (TF) binding sites of TFs that are also not expressed in leaf tissue. The leaf-iUMRs exhibit unique chromatin modification patterns and are enriched for chromatin interactions with nearby genes. The total UMRs space in four additional monocots ranges from 80-120 megabases, which is remarkably similar considering the range in genome size of 271 megabases to 4.8 gigabases. In summary, based on the profile from a single tissue, DNA methylation signatures pinpoint both accessible regions and regions poised to become accessible or expressed in other tissues. UMRs provide powerful filters to distill large genomes down to the small fraction of putative functional genes and regulatory elements.Significance StatementCrop genomes can be very large with many repetitive elements and pseudogenes. Distilling a genome down to the relatively small fraction of regions that are functionally valuable for trait variation can be like looking for needles in a haystack. The unmethylated regions in a genome are highly stable during vegetative development and can reveal the locations of potentially expressed genes or cis-regulatory elements. This approach provides a framework towards complete annotation of genes and discovery of cis-regulatory elements using methylation profiles from only a single tissue.

The development of efficient electrode materials is essential to promote the performance of energy storage equipment. Nowadays, metal organic frameworks (MOFs) have been widely regarded as active materials for supercapacitors mainly thanks to their adjustable structure and outstanding porosity. Here, highly optimized Nickel and Cobalt MOF-derived N-doped porous carbon (Ni/Co-MOF-NPC) are considered the best choice for electrode materials due to their unique structural properties and excellent electrochemical performance. Pure cobalt oxide rarely reaches a specific capacitance of 104.3 F g-1 when the current density is 1 A g-1, but the optimized Ni/Co-MOF-NPC-2:1 offers an ultra-high specific capacitance of 1214 F g-1, which is much higher than that of pure cobalt oxide in a three-electrode test system. When the current density is 10 A g-1, after 6000 cycles, the capacitance can still maintain 98.8% of the initial capacitance. Asymmetric supercapacitors were assembled using the prepared Ni/Co-MOF-NPC-2:1 as the positive electrode material, corrugated paper activated carbon (CPAC) as the negative electrode material, the prepared Ni/Co-MOF-NPC-2:1//CPAC exhibits an outstanding energy density of 55.4 Wh kg-1 at 758.5 W kg-1, and has a significant cycle stability of 75.2% retention after 20,000 cycles. This excellent MOF synthesis strategy reduced the gap between the experimental synthesis and practical application of MOF in fast energy storage.

Green and sustainable electrochemical conversion and storage devices possess the nature to repress a negative effect on sustainability during energy conversion and storage. However, the sustainabil...

Photocatalytic reforming of renewable and low-cost biomass is an alternative approach to synthesize high-value-added multicarbon compounds and hydrogen. However, the difficulty in activating the me...

Since Moore’s law in the traditional semiconductor industry is facing shocks, More Moore and More than Moore are proposed as two paths to maintain the development of the semiconductor industry by adopting new architectures or new materials, in which the former is committed to the continued scaling of transistors for performance enhancement, and the latter pursues the realization of functional diversification of electronic systems. Two-dimensional (2D) materials are supposed to play an important role in these two paths. In More Moore, the ultimate thin thickness and the dangling-bond-free surface of 2D channels offer excellent gate electrostatics while avoiding the degradation of carrier mobility at the same time, so that the transistors can be further scaled down for higher performance. In More than Moore, devices based on 2D materials can well meet the requirements of electronic systems for functional diversity, like that they can operate at high frequency, exhibit excellent sensitivity to the changes in the surroundings at room temperature, have good mechanical flexibility, and so on. In this review, we present the application of 2D materials in More Moore and More than Moore domains of electronics, outlining their potential as a technological option for logic electronics, memory electronics, radio-frequency electronics, sensing electronics, and flexible electronics.

In this work, the ternary diffusion behavior in fcc Ni-Fe-V system has been investigated by means of solid-state diffusion couple technique at 1000, 1100 and 1200 °C. The composition-dependent ternary interdiffusion coefficients were determined via Whittle-Green method, in which the uncertainties were calculated by error propagation and the reliability was validated via thermodynamic constraints. The ternary main interdiffusion coefficients of $$\tilde{D}_{\text{FeFe}}^{\text{Ni}}$$ and $$\tilde{D}_{\text{VV}}^{\text{Ni}}$$ were compared with the ones in binary Fe-Ni and Ni-V systems in the literature, respectively. The obtained interdiffusion coefficients combined with the thermodynamic description were employed to evaluate the atomic mobilities in fcc Ni-Fe-V system through the DICTRA (DIffusion-Controlled TRAnsformations) software package. A comprehensive comparison between the model-predicted diffusion behaviors and the experimental ones, including concentration/interdiffusion-flux distribution and diffusion path, confirms the reliability of the present atomic mobility. Besides, based on the presently obtained atomic mobilities, three-dimensional surfaces for the diagonal interdiffusivity at 1000, 1100 and 1200 °C were plotted. Furthermore, three-dimensional planes of the activation energy and frequency-factor of main interdiffusivities were evaluated using the Arrhenius equation. This work is part of our work to build a general kinetic database for soft magnetic alloys and cemented carbides.

This article first presents the characteristics of the iron and steel industry of China during 2018. Then the production, raw material and operation indexes of the large blast furnaces of China in ...