Electrocatalytic organic compound oxidation reactions (OCORs) have been intensively studied for energy and environmentally benign applications. However, relatively little effort has been devoted to ...developing a fundamental understanding of OCORs, including the detailed competition with side reactions and activity limitations, thus inhibiting the rational design of high-performance electrocatalysts. Herein, by taking the NiWO
4
-catalysed urea oxidation reaction (UOR) in aqueous media as an example, the competition between the OCOR and the oxygen evolution reaction (OER) within a wide potential range is examined. It is shown that the root of the competition can be ascribed to insufficient surface concentration of dynamic Ni
3+
, an active site shared by both the UOR and OER. A similar phenomenon is observed in other OCOR electrocatalysts and systems. To address the issue, a "controllable reconstruction of pseudo-crystalline bimetal oxides" design strategy is proposed to maximise the dynamic Ni
3+
population and manipulate the competition between the UOR and the OER. The optimised electrocatalyst delivers best-in-class performance and an ∼10-fold increase in current density at 1.6 V
versus
the reversible hydrogen electrode for alkaline urea electrolysis compared to those of the pristine materials.
A detrimental competition between the urea oxidation reaction (UOR) and oxygen evolution reaction is identified. Strategies are proposed to alleviate such competition and boost the performance of the UOR and other organic compound oxidation reactions.
Digital coding metasurfaces use binary digital states to represent the amplitude or phase of reflected or transmitted waves, and digitally characterize the electromagnetic properties of metasurfaces. ...To simplify the structure of the digitally encoded metasurface unit, we design a 3-bit geometric phase-encoded unit structure using the geometric phase principle. Based on the loss characteristics of metal materials, which seriously affect the device efficiency, we propose to use all-dielectric materials to construct an encoding unit, and then realize a terahertz wave all-dielectric geometric phase encoding metasurface. The coding metasurface can effectively control the far-field scattering angle of the incident wave. By arranging the coding units on the front surface according to different digital sequences, digital coding metasurfaces with corresponding different functions can be realized. However, based on the generalized Snell's law, the regulation of the scattering angle is limited by the period of the encoded structure. To obtain the free control of the scattering angle, we use the Fourier convolution principle in digital signal processing to perform addition and subtraction operations on different coding sequences to obtain the free control of the deflection of the abnormally scattered beam. At the same time, we also design a new checkerboard encoding metasurface that mixes gradient encoding and checkerboard encoding, which can simultaneously control four beams of anomalous scattered light.
Two‐dimensional (2D) PtSe2 shows the most prominent layer‐dependent electrical properties among various 2D materials and high catalytic activity for hydrogen evolution reaction (HER), and therefore, ...it is an ideal material for exploring the structure–activity correlations in 2D systems. Here, starting with the synthesis of single‐crystalline 2D PtSe2 with a controlled number of layers and probing the HER catalytic activity of individual flakes in micro electrochemical cells, we investigated the layer‐dependent HER catalytic activity of 2D PtSe2 from both theoretical and experimental perspectives. We clearly demonstrated how the number of layers affects the number of active sites, the electronic structures, and electrical properties of 2D PtSe2 flakes and thus alters their catalytic performance for HER. Our results also highlight the importance of efficient electron transfer in achieving optimum activity for ultrathin electrocatalysts. Our studies greatly enrich our understanding of the structure–activity correlations for 2D catalysts and provide new insight for the design and synthesis of ultrathin catalysts with high activity.
Through thick and thin: Since the thickness of two‐dimensional (2D) PtSe2 flakes can be controlled by adjusting synthesis conditions, their layer‐dependent catalytic activity for the hydrogen evolution reaction could be investigated from both theoretical and experimental perspectives. Structure–activity correlations were drawn, providing new insights for the design and synthesis of ultrathin catalysts.
Organic polymers are becoming emerging thermoelectric materials. Tremendous progress has been achieved for p-type doping, but efficient n-type organic materials are still rare. By investigating ...potassium-doped n-type poly(nickel-ethylenetetrathiolate) using density functional theory coupled with Boltzmann transport equation, we find that (i) formation of the electron polaron band (EPB) split from the conduction band (CB) dominates electron transport; (ii) at low doping concentration, the upper CB gets involved in transport in addition to the EPB as the temperature rises, leading to a highly elevated Seebeck coefficient and power factor; and (iii) at even higher temperature, because the CB starts to dominate, the Seebeck coefficient levels off and then decreases with temperature. Such an “exotic” nonmonotonic temperature effect has been found in experiment but has never been explained. We find that such behavior is primarily due to a polaron effect. A doping-induced polaron band can be employed to boost the Seebeck coefficient, making the organic coordination polymer a peculiar n-type thermoelectric material.
Long noncoding RNAs have been identified as important regulators of gene expression and animal development. The expression of natural antisense transcripts (NATs) transcribed in the opposite ...direction to protein-coding genes is usually positively correlated with the expression of homologous sense genes and is the key factor for expression. Here, we identified a conserved noncoding antisense transcript, CFL1-AS1, that plays an important role in muscle growth and development. CFL1-AS1 overexpression and knockout vectors were constructed and transfected into 293T and C2C12 cells. CFL1-AS1 positively regulated CFL1 gene expression, and the expression of CFL2 was also downregulated when CFL1-AS1 was knocked down. CFL1-AS1 promoted cell proliferation, inhibited apoptosis and participated in autophagy. This study expands the research on NATs in cattle and lays a foundation for the study of the biological function of bovine CFL1 and its natural antisense chain transcript CFL1-AS1 in bovine skeletal muscle development. The discovery of this NAT can provide a reference for subsequent genetic breeding and data on the characteristics and functional mechanisms of NATs.
Long non-coding RNAs (LncRNAs) are dysregulated in a variety of human diseases and are highly involved in the development and progression of tumors. Studies on lncRNAs associated with cow mastitis ...have been lagging behind compared to humans or model animals, therefore, the aim of this study was to explore the mechanism of LncRNAs (CMR) involved in autoprotection against S. aureus mastitis in Bovine Mammary Epithelial Cells (BMECs). First, qRT-PCR was used to examine the relative expression of CMR in a S. aureus mastitis model of BMECs. Then, cell proliferation and apoptosis were detected by EdU and apoptosis assay. Finally, the targeting relationship between miRNAs and mRNA/LncRNAs was determined by dual luciferase reporter gene, qRT-PCR and western blotting techniques. The results showed that CMR was upregulated in the S. aureus mastitis model of BMECs and promoted the expression of inflammatory factors, and SiRNA-mediated CMR inhibited the proliferation of mammary epithelial cells and induced apoptosis. Mechanistically, CMR acts as a competitive endogenous RNA (ceRNA) sponge miR-877, leading to upregulation of FOXM1, a target of miR-877. Importantly, either miR-877 overexpression or FOXM1 inhibition abrogated CMR knockdown-induced apoptosis promoting cell proliferation and reducing inflammatory factor expression levels. In summary, CMR is involved in the regulation of autoprotection against S. aureus mastitis through the miR-877/FOXM1 axis in BMECs and induces immune responses in mammary tissues and cells of dairy cows, providing an important reference for subsequent prevention and control of cow mastitis and the development of targeted drugs.
•LncRNA CMR is significantly up-regulated in S. aureus induced mastitis and can inhibit inflammation.•Knockdown CMR can up-regulate the expression of miR-877, inhibit the proliferation of bovine mammary epithelial cells and induce apoptosis.•miR-877/FOXM1 plays an important role in the development of cow mastitis.•CMR can regulate the expression of FOXM1 through sponge miR-877, and affect the expression of inflammatory factors as well as the proliferation and apoptosis of bovine mammary epithelial cells, promoting the recovery of damaged tissues after bacterial invasion.
Triangular decomposition with different properties has been used for various types of problem solving. In this paper, the concepts of pure chains and square-free pure triangular decomposition (SFPTD) ...of zero-dimensional polynomial systems are defined. Because of its good properties, SFPTD may be a key way to many problems related to zero-dimensional polynomial systems. Inspired by the work of Wang (2016) and of Dong and Mou (2019), the authors propose an algorithm for computing SFPTD based on Gröbner bases computation. The novelty of the algorithm is that the authors make use of saturated ideals and separant to ensure that the zero sets of any two pure chains are disjoint and every pure chain is square-free, respectively. On one hand, the authors prove the arithmetic complexity of the new algorithm can be single exponential in the square of the number of variables, which seems to be among the rare complexity analysis results for triangular-decomposition methods. On the other hand, the authors show experimentally that, on a large number of examples in the literature, the new algorithm is far more efficient than a popular triangular-decomposition method based on pseudodivision, and the methods based on SFPTD for real solution isolation and for computing radicals of zero-dimensional ideals are very efficient.
PDF
