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Emerging power batteries with both high volumetric energy density and fast charge/discharge kinetics are required for electric vehicles. The rapid ion/electron transport of mesostructured electrodes enables a high electrochemical activity in secondary batteries. However, the typical low fraction of active materials leads to a low volumetric energy density. Herein, we report a novel biomimetic “bee pupa infilled honeycomb”-structured 3D mesoporous cathode. We found previously the maximum active material filing fraction of an opal template before pinch-off was about 25%, whereas it could be increased to ∼90% with the bee pupa-infilled honeycomb-like architecture. Importantly, even with a high infilling fraction, fast Li+/e− transport kinetics and robust mechanical property were achievable. As the demonstration, a bee pupa infilled honeycomb-shaped Li2MnSiO4/C cathode was constructed, which delivered a high volumetric energy density of 2443 W h L−1. The presented biomimetic bee pupa infilled honeycomb configuration is applicable for a broad set of both cathodes and anodes in high energy density batteries. [ABSTRACT FROM AUTHOR]

Impulsive noise interference can seriously affect the performance of underwater acoustic communication systems. An impulsive noise suppression method based on regularized threshold iteration was presented. Firstly, the null subcarrier matrix was used to separate impulsive noise from Gaussian white noise and useful signals. Then, based on the theory of compressed sensing, the impulsive noise estimation problem was transformed into a regularization problem by introducing a threshold iteration, and the impulsive noise was estimated by using a threshold function to obtain the estimated value of the impulsive noise. Finally, the estimated impulsive noise was subtracted from the received signal. The simulation results show that the proposed method can effectively reduce the bit error rate (BER) and mean square error (MSE), and improve the reliability of signal transmission in underwater acoustic communication environment. [ABSTRACT FROM AUTHOR]

Aflatoxin B1 (AFB1) is the most toxic mycotoxin of the aflatoxins (AFs) and shows carcinogenic, teratogenic and mutagenic effects in humans and animals. AFB1 is widely seen in cereal products such as rice and wheat. This research proposed a low-cost, high-sensitivity fluorescence polarization (FP) assay for detection of AFB1 using aptamer biosensors based on graphene oxide (GO). The aptamers labelled with fluorescein amidite (FAM) were adsorbed on the surface of GO through π-π stacking and electrostatic interaction, thus forming aptamer/GO macromolecular complexes. Under these conditions, the local rotation of fluorophores was limited and the system had a high FP value. When there was AFB1 in the system, aptamers were dissociated from the GO surface and combined with AFB1 owing to their specificity to form aptamer/AFB1 complexes. As a result, large changes were observed in the molecular weights of aptamers before, and after, the combination, therefore leading to the apparent changes in FP value. The results showed that when only 10 nM of aptamer was used, the changes in FP and the AFB1 concentration had a favourable linear relationship within 0.05 to 5 nM of AFB1, and the lowest detection limit (LOD) was 0.05 nM. In addition, the recoveries of rice sample extract ranged from 89.2% to 112%. The method is simple, highly sensitive, cost-efficient and shows potential application prospects. [ABSTRACT FROM AUTHOR]

In this paper, the decomposition of Rhodamine B (RhB) by hydrodynamic cavitation (HC), acoustic cavitation (AC) and the combination of these individual methods (HAC) have been investigated. The degradation of 20 L RhB aqueous solution was carried out in a self-designed HAC reactor, where hydrodynamic cavitation and acoustic cavitation could take place in the same space simultaneously. The effects of initial concentration, inlet pressure, solution temperature and ultrasonic power were studied and discussed. Obvious synergies were found in the HAC process. The combined method achieved the best conversion, and the synergistic effect in HAC was even up to 119% with the ultrasonic power of 220 W in a treatment time of 30 min. The time-independent synergistic factor based on rate constant was introduced and the maximum value reached 40% in the HAC system. Besides, the hybrid HAC method showed great superiority in energy efficiency at lower ultrasonic power (88–176 W). Therefore, HAC technology can be visualized as a promising method for wastewater treatment with good scale-up possibilities. [ABSTRACT FROM AUTHOR]

In this work, we describe a palladium-catalyzed intermolecular O acylation of α-diazoesters with ortho-bromobenzaldehydes. The C(sp2)−H bond activation of the aldehyde is enabled by migratory insertion of a palladium carbene intermediate. The diazoesters act as modular three-atom units to build up key seven-membered palladacycles, which are transformed into a variety of isocoumarin derivatives upon reductive elimination. Mechanistic experiments and DFT calculations provide insight into the reaction pathway. [ABSTRACT FROM AUTHOR]

Wastewater treatment plant (WWTP) effluent is discharged into rivers as supplemental water, which may result in ecological risk. This study compares the element composition and microbial community of WWTP effluent and natural surface water (NSW) and reveals the potential ecological risk of WWTP effluent discharge. Twenty recently upgraded WWTPs and three relatively large reservoirs in Zhengzhou city, China, were selected. The contents of N, P, S, K, Ca, Mg, B, Si, Na, Fe, Mn, Co, Ni and Sn were significantly higher in WWTP effluent than in NSW, while those of Mo, V, Pb and Cd were significantly lower. There was no significant difference between WWTP effluent and NSW in terms of the element imbalance index (IMI) (representing the extent of imbalance of element proportions) relative to the class IV surface water quality standard (the control standard for most Chinese rivers). The macronutrient IMI relative to the Hoagland formula was significantly lower in WWTP effluent than in NSW, and WWTP effluent discharge could significantly lower this index in NSW; this may be an important cause of primary productivity explosion. The microbial diversity was significantly higher in WWTP effluent than in NSW. The predicted relative abundances of mobile genetic elements and oxidative-stress-tolerant phenotypes were significantly higher in WWTP effluent than in NSW, whereas the abundance of gram-negative phenotypes was significantly lower, and that of potential pathogenic phenotypes was slightly lower. The effluent from upgraded WWTPs exhibited a low risk of pathogen diffusion but a high risk of antibiotic resistance gene diffusion. The element composition and microbial community should be considered when evaluating the ecological risk of WWTP effluent discharge. [Display omitted] • WWTP effluent discharge can alleviate the macronutrient imbalance in the receiving water. • Alleviation of elemental imbalance can lead to problems related to eutrophication. • Upgraded WWTP effluent discharge has a low risk of pathogen diffusion. • Upgraded WWTP effluent discharge has a high risk of antibiotic resistance gene diffusion. [ABSTRACT FROM AUTHOR]

Chlorella is a dominant species during harmful algal blooms (HABs) worldwide, which bring about great environmental problems and are also a serious threat to drinking water safety. Application of bacterial algicides is a promising way to control HABs. However, the identified bacterial algicides against Chlorella and the understanding of their effects on algal metabolism are very limited. Here, we isolated a novel bacterium Microbacterium paraoxydans strain M1 that has significant algicidal activities against Chlorella vulgaris (algicidal rate 64.38 %, at 120 h). Atrazine-desethyl (AD) was then identified from strain M1 as an effective bacterial algicide, with inhibition or algae-lysing concentration values (EC 50) of 1.64 μg/mL and 1.38 μg/mL, at 72 h and 120 h, respectively. LAD (2 μg/mL AD) or HAD (20 μg/mL AD) causes morphology alteration and ultrastructure damage, chlorophyll a reduction, gene expression regulation (for example, psbA , 0.05 fold at 24 h, 2.97 fold at 72 h, and 0.23 fold of the control in HAD), oxidative stress, lipid oxidation (MDA, 2.09 and 3.08 fold of the control in LAD and HAD, respectively, at 120 h) and DNA damage (average percentage of tail DNA 6.23 % at 120 h in HAD, slight damage: 5∼20 %) in the algal cells. The impacts of AD on algal metabolites and metabolic pathways, as well as the algal response to the adverse effects were investigated. The results revealed that amino acids, amines, glycosides and urea decreased significantly compared to the control after 24 h exposure to AD (p < 0.05). The main up-regulated metabolic pathways implied metabonomic resistance and defense against osmotic pressure, oxidative stress, photosynthesis inhibition or partial cellular structure damage, such as phenylalanine metabolism, arginine biosynthesis. The down-regulated glycine, serine and threonine metabolism is a major lead in the algicidal mechanism according to the value of pathway impact. The down-regulated glycine, and serine are responsible for the downregulation of glyoxylate and dicarboxylate metabolism, aminoacyl-tRNA biosynthesis, glutathione metabolism, and sulfur metabolism, which strengthen the algae-lysing effect. It is the first time to highlight the pivotal role of glycine, serine and threonine metabolism in algicidal activities, which provided a new perspective for understanding the mechanism of bacterial algicides exerting on algal cells at the metabolic level. [Display omitted] • M. paraoxydans strain M1 shows algicidal activities against Chlorella vulgaris. • Atrazine-desethyl (AD) was identified as the effective algicidal substance. • AD cause photosynthesis inhibition, oxidative stress, lipid oxidation, DNA damage. • AD induces metabonomic resistance in Chlorella vulgaris. • Algicidal activities of AD down-regulate glycine, serine and threonine metabolism. [ABSTRACT FROM AUTHOR]

We undertook a novel batch production approach for the synthesis of CeO nanopowders doped with rare earth elements. Solid solution nanopowders of CeLaO ( x = 0.15) were successfully synthesized in a large-scale and low-cost production by hydrolyzing and oxidizing Ce-La-C alloys at room temperature and subsequent calcining of their powders at different temperatures (873-1073 K) for 1 h. The Ce-La-C alloys were prepared in a vacuum induction melting furnace. The final products were characterized by x-ray diffraction, transmission electron microscopy, Brunner-Emmet-Teller (BET) surface area analyzer, and Raman spectroscopy. The calculated lattice parameters of the cubic fluorite-type phase of CeO tended to increase when La was incorporated into CeO. The F band shift and the absence of a peak corresponding to LaO in the Raman spectra consistently confirmed the incorporation of the La ion into CeO, and the formation of CeLaO solid solutions as manifested by increased oxygen vacancy defects. High-quality CeLaO nanopowders of ~10-15 nm diameter with a high BET surface area of ~77 m g were obtained. The average crystallite size of CeLaO was found to be smaller than that of CeO for the same calcination temperature of 1073 K, demonstrating that the introduction of La into CeO can stabilize the host lattice and refine the grain size at high temperatures. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study of the nonlinear characteristics of an axially moving string. An experimental system with a simple configuration, which is similar to a practical application, was built. Two laser sensors were used to monitor the vertical and horizontal vibrations of the moving string under different conditions. Using the Hilbert-Huang transform method, the detailed results of a typical measured data series, which include intrinsic mode decomposition, Hilbert spectrum and marginal spectrum, are introduced. For comparison, marginal spectra for almost all test cases are also given. Based on the results, several observed nonlinear phenomena, which include whirling motion, resonances, quasiperiodical and a beating motion, torus doublings and one chaotic motion, are presented. The quantitative nonlinear vibrating details and the observed rich behaviors help explain the great complexity of a single moving string. [ABSTRACT FROM AUTHOR]

Aggregates are secondary particles formed through the combination of mineral particles glued by organic and inorganic substances. Soil compaction caused by mechanical tillage practices mainly affects its structure and function by the dispersing, braking, re-proportioning, re-arranging and re-combining aggregates. Although mechanical compaction was reported to reduce the proportion of soil water stable aggregate with size smaller than 0.25 mm, how further impact of mechanical compaction on composition and stability of soil micro-aggregate is still unknown. Comparing to the study of soil macro-aggregates, research on soil micro-aggregates can contribute to a better understanding of disperse strength and structural performance of primary aggregates under particular conditions. Based on the cropland soil in the typical black soil region of Northeast China, the influence of mechanical compaction on soil micro-aggregate composition and stability was studied by measuring and analyzing the soil micro-aggregate distribution, mean weight soil specific area (MWSSA), fractal dimension (D) and dispersion coefficient at different soil depths (0-20 cm, > 20-40 cm, and >40-80 cm). The results showed that mechanical compaction mainly reduced the proportion of macro-aggregate (≥0.25 mm) and increased the proportion of small-sized (<0.002 mm) micro-aggregate in the 0-20 cm soil depth. The MWSSA, D value and dispersion coefficient were significantly higher than control condition (P<0.05) when the number of mechanical compaction passes increased 12 times, indicating that repeated compaction could cause a significant reduction on soil micro-aggregate stability. In the soil depth > 20-40 cm, mechanical compaction primarily affected the proportion of micro-aggregates with diameter of 0.05-0.25 mm and <0.002 mm. The MWSSA, and D value of soil micro-aggregates decreased significantly (P<0.05) when the mechanical compaction treatment was only 3 passes but the proportion of each size aggregate distributed uniformly. However, these measurements increased significantly when the compaction passes increased to 12 times (P<0.05), which also indicated that repeated compaction caused a significant reduction on soil micro-aggregate stability. The only difference was that a few times of compaction (3 passes) could promote the reunion of the small-sized micro-aggregates and extenuate the destruction of relative bigger sized micro-aggregates. Within the >40-80 cm soil layer, the proportion of middle-class micro-aggregates (> 0.05-0.25 mm and > 0.02-0.05 mm) reduced, but macro-aggregate (≥0.25 mm) and smaller sized micro-aggregate (<0.002 mm) increased, which resulted in a non -uniformed distribution pattern of different sized micro-aggregates. Soil MWSSA, D value and dispersion coefficient increased gradually with increasing the passes of traffic, indicating even few passes of compaction could significantly reduce the stability of the soil micro-aggregates, and the mechanical compaction had a significant cumulative effect on deeper soil layer (>40-80 cm). This result confirmed the former research conducted in this area with the same traffic machine. The proportion of <0.002 mm micro-aggregate (clay content) had a highly significant correlation with the other micro-aggregates characteristic indices (P<0.05), which suggested to be an effective parameter to reflect soil micro-aggregates dispersion, reunion and stability. In summary, mechanical tillage compaction tended to increase the smaller sized micro-aggregate composition and reduce its stability, especially for the deeper soil (>40-80 cm). The findings showed that cumulative compaction effects on subsurface area and deeper soil layer can not be neglected, and may serve as theoretical basis for scientifically evaluating soil compaction and quality evolution in typical black soil region. [ABSTRACT FROM AUTHOR]