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The p-block elements are evaluated as axial ligands of single-atom Mo for highly efficient two-electron CO 2 reduction reaction. [Display omitted] • Single-atom Mo modified by 20 p-block elements as axial ligands was studied by first-principles calculation. • The axial ligand had a significant effect on adsorption strength of Mo atom for CO 2 RR intermediates. • Ge-MoN 4 exhibited the best performance in the two-electron CO 2 RR. • The CO 2 RR activity was related to the inherent properties of the axial ligands. Inspired by the structure of molybdenum-based metalloenzymes with high CO 2 conversion efficiency in nature, the catalytic performance of a series of modified MoN 4 for two-electron CO 2 reduction reaction (CO 2 RR) was systematically studied using first-principles calculations. The effect of 20 p-block elements as axial ligands on the structure of MoN 4 was evaluated. Benefiting from the significant effect of the axial ligands on the adsorption strength of Mo for intermediates, both activity and selectivity were improved, especially Ge-MoN 4 exhibited the best performance in the formic acid (HCOOH) pathway. The orbital hybridization between Mo and the intermediate was weakened to varying degrees by axial ligands. Furthermore, the activity of the catalysts was related to the properties of the axial ligands, especially the Mo-N bond length and the electronegativity difference between Mo and the axial ligands. This work provides a thorough understanding and guidance for modifying the coordination environment of single-atom catalysts for CO 2 RR. [ABSTRACT FROM AUTHOR]

• Visualized model tests are adopted to simulate the tunnel joint leakage with different water environments. • The damage evolutional process of sand erosion and erosion void are investigated in the model tests. • The theoretical model is proposed to predict the volumetric flow rate of the sand erosion and the volume of the erosion void. Sand erosion induced by shield-tunnel joint leakage is one of the most frequent catastrophes, causing ground collapses and tunnel failures. In this paper, a self-designed test device that considers differences in water head, burial depth and leaky joint characteristics was used to investigate sand erosion and void development. The experimental results show that the development of sand erosion has obvious temporal and spatial evolution characteristics. In the temporal dimension, sand erosion development can be divided into four stages: vertical erosion, cavity formation, coarse-particle skeleton distribution (CPSR) and steady seepage. In the spatial dimension, it can be divided into three regions: the stable zone, slip surface and eroded zone shape. It is found that the erosion zone can be described by a rotating ellipsoid and the scope of the erosion zone increases with increasing water head, whereas the influence of the burial depth is not significant. The influence of the invert leakage on the volume flow rate is also determined to be larger than that of the vault leakage and the volume flow rate rapidly increases when the size of the leaky joint exceeds the critical outlet size. Finally, a theoretical model based on the test results is proposed to predict the volumetric flow rate of sand erosion. [ABSTRACT FROM AUTHOR]

In 2018, a disease characterized by splenic hemorrhage and necrosis killed ducks in a duck farm in Guangxi province, China. A duck reovirus strain was isolated from the tissues of the dead ducks by inoculating duck embryos and BHK-21 cells. Electron microscopy of the cultured the isolate showed that the viral particles were nearly round in shape and approximately 70 nm in diameter, and they were designated DRV-GL18. Sequence analysis showed that the GL18 strain viral genome was 23,419 nt in length and had 10 dsRNA segments. Phylogenetic analysis of cDNA amplicons of segments encoding the protein σC which are outer capsid proteins showed that the isolate belongs to the branch of the epidemic strains of duck reovirus. The Recombination Detection Program (RDP) and SimPlot program analyses suggested potential genetic recombination events in the M2 segments. Pathogenicity experiments revealed that GL18 produced severe hemorrhaging in livers and necrosis in the spleen of infected SPF ducklings. A death rate of 50% in the experimental ducklings was calculated during the first 7 d, and the rest of the ducklings were observed to undergo spleen necrosis. These data suggested that GL18 is a duck reovirus isolate with severer pathogenicity, and it could be a candidate for development of vaccine. This is the first reported isolation of duck reovirus from mature ducks. [ABSTRACT FROM AUTHOR]

A simple solvothermal synthetic method was proposed for the fabrication of metal organic framework/grapheme oxide hybrid nanocomposite (UiO-67/GO), achieving dense and ordered UiO-67 on the surface of GO for the high-affinity capture of organophosphorus pesticides (OPPs). The composites were characterized by SEM, XRD, FTIR and TGA. The adsorption process and adsorption capacity of glyphosate was evaluated by kinetics and equilibrium adsorption isotherm study, respectively. The results indicate that the pseudo-second-order kinetic model and the Langmuir model correlated satisfactorily to the experimental data. The maximum adsorption capacity of glyphosate on UiO-67/GO is ∼2.855 mmol (482.69 mg) g −1 at pH 4, which catches up with and even surpasses that of most GO-based adsorbents. The excellent adsorption performances of UiO-67/GO toward OPPs are also presented in a wide range of pH 2–8. Moreover, the adsorption mechanism was further revealed using XPS and FTIR. Taking advantage of the abundant Zr OH groups on the surface of GO, as well as the large surface of available GO for enhancing the sequestration of target organophosphorus-pollutants, the as-prepared UiO-67/GO composites exhibit enhancement of adsorption capacity toward glyphosate. The experimental results suggest that the UiO-67/GO is a promising adsorbent for efficient removal of OPPs for the contaminated water purification. [ABSTRACT FROM AUTHOR]

• The landscape pattern of farming-land has impacts on soil- and vegetation- indicators of wetland. • The degradation of remnant wetland (IDRW) can be modeled by soil- and vegetation- indicators. • The landscape pattern of surrounding cultivated-land can present IDRW by simulation. Human activities, especially cultivated-land reclamation, substantially influence landscape patterns. This phenomenon leads to a sharp decrease in wetland areas and wetland function degradation. To understand the impact of changing landscape patterns of the cultivated land on remnant wetland degradation and to formulate highly targeted control measures, considering a farmland-wetland mosaic landscape in the Sanjiang Plain as an example, this study explored the response of soil- and vegetation-related indicators of remnant wetlands under the influence of changing cultivated land patterns. Correlations between cultivated land patterns and soil- and vegetation-indicators in different buffer zones of remnant wetland sample points were discussed. On the basis of modeling an index of the integrated degradation degree of remnant wetlands (IDRWs) using soil- and vegetation-indicators, the correlation between cultivated land patterns and IDRW was analysed. The results showed that: 1) five soil-related indexes of remnant wetlands were lower than those of natural wetlands, and nine vegetation-related indexes of remnant wetlands were higher than those of natural wetlands; 2) the variation in soil- and vegetarian-related indexes caused by changing cultivated land patterns in a certain range of remnant wetlands was significant (P < 0.05) and these indexes could potentially be used as variables to model IDRW; and 3) the aggregation degree of wetland patches was the main landscape index for IDRW simulation (from 1995 to 2015, the proportion of serious degradation of the Sanjiang Plain wetland first decreased in 2010 and then increased, and that of slight degradation first increased in 2010 and then decreased, indicating that wetland protection and restoration plans have shown progress after 2010). Our study discussed the impacts of cultivated land patterns on remnant wetland degradation and developed a simulation method of degraded remnant wetlands to provide a reference for the wetland protection, restoration, degradation monitoring, and reclamation planning for the cultivated lands in the future. [ABSTRACT FROM AUTHOR]

Duck adenoviruses (DAdVs) include serotype 1 (DAdV-1) in the genus Atadenovirus and serotypes 2-4 (DAdV-2, 3, and 4) in the genus Aviadenovirus. DAdV-3 was initially isolated from Chinese Muscovy ducks in 2014, whereby the infected ducks exhibited yellowing and hemorrhaging in the liver, along with slight pericardial effusion, swelling, and hemorrhaging in the kidneys. In recent years, duck adenovirus infections have appeared in Muscovy duck farms in Fujian, Zhejiang, Anhui, Guangdong, and other places in China. They have an incidence rate of 40 to 55% and a mortality rate of 35 to 43%, resulting in great losses to the duck breeding industry. In this study, 7 DAdV-3 strains, designated as TZ193, FJPT20161124, GX20170519, FJZZ, GDMM, AHAQ, and GDHS were isolated from Muscovy ducks in different provinces of China during 2016–2019, and their complete genomics were sequenced. Their genomes all exhibited significant deletions in ORF67 , which also had G to A transitions at the 41st and 977th nt positions, resulting in a stop codon. The pathogenicity of TZ193, a novel isolate of DAdV-3, was investigated in Muscovy ducks. TZ193 caused characteristic lesions of swelling as well as hemorrhagic liver and kidney in the infected ducklings. Moreover, the mortality rate of TZ193 in 5-day-old domestic ducks was 100%. Our data provide concrete evidence for the identification of the DAdV-3 novel variant mutant in China, which effects increased mortality in ducks. This highlights the necessity for monitoring the specific molecular epidemiology of novel DAdV-3 mutants and the development of new vaccines in the future. [ABSTRACT FROM AUTHOR]

Aimed at solving food poisoning and food-borne diseases caused by drug-resistant pathogens bacteria, the optimum utilization of abundant, green, and sustainable sunlight through photocatalytic technology is definitely an appealing task. Herein, a new series of AgI@MnO 2 X:1 (X = 5, 10, 15) heterostructure photocatalysts were synthesized by in-situ growth of AgI nanoparticles on the surface of MnO 2 microspheres using the deposition method. Compared with MnO 2 or AgI alone, the AgI@MnO 2 heterostructure system exhibited enhanced photocatalytic performance due to the improved rapid separation efficiency of photogenerated electron-hole pairs. Moreover, AgI@MnO 2 10:1 had higher photocurrent density and more ROS production, indicating the accelerated charge transfer and increased photocatalytic efficiency. Based on this, the photocatalytic mechanism was proposed. The antibacterial experiment verified the excellent broad-spectrum bactericidal performance of AgI@MnO 2 10:1 against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), which was because AgI@MnO 2 10:1 with high catalytic activity under visible light would generate more ROS by consuming glutathione (GSH) to improve antibacterial efficiency. This study provides new insight into the development of superior general photocatalyst for environmental disinfection, healing wounds from bacterial infections, and other fields that quickly kill bacteria. • AgI@MnO 2 has higher use efficiency of visible light than AgI and MnO 2. • AgI@MnO 2 has higher separation efficiency of photo-induced electron-hole pairs. • The mechanism for the enhanced photocatalytic activity of AgI@MnO 2 is revealed. • AgI@MnO 2 has a superior photocatalytic activity for the sterilization of E. coli and S. aureus. [ABSTRACT FROM AUTHOR]