Analytical Modeling of Wave Absorption Performance in Gradient Graphene/Polymer Nanocomposites.

Due to the low impedance matching caused by the high dielectric permittivity of graphene, the strong absorption of electromagnetic waves by graphene/polymer nanocomposites is challenging. In this paper, an analytical model for microwave absorption based on Maxwell's equation and the effective medium theory, considering the interface effect, was constructed to explore the effect of the gradient distribution of graphene in the polymer matrix on its microwave absorption performance. The outcome indicated that the impedance of the composites matched well with the air, and its attenuation ability for electromagnetic waves was obviously improved as the graphene concentration was distributed in a gradient form. For instance, when the thickness of the material is 10 mm, based on the optimal concentration of the homogeneous composites being 0.7 wt%, the graphene concentration range of the gradient composites is set to 0.7-0.9 wt% and distributed in three gradient forms of linear, parabolic, and 0.5 power. The results show that the microwave absorption performance is significantly improved compared with the homogeneous composites. Among them, the effective bandwidth on the 0.5 power distribution is 5.2 GHz, 0.5 GHz higher than that of the homogeneous composites. The minimum reflection loss (RL) is as low as -54.7 dB, which is 26.26 dB lower than that of the homogeneous composites. This paper contributes to the design and application of gradient absorbing structures.

Effects of the coexistence of antibiotics and heavy metals on the fate of antibiotic resistance genes in chicken manure and surrounding soils.

Both heavy metals and antibiotics exert selection pressure on bacterial resistance, and as they are commonly co-contaminated in the environment, they may play a larger role in bacterial resistance. This study examined how breeding cycles affect antibiotic resistance genes (ARGs) in chicken manure and the surrounding topsoils at 20, 50, 100, 200, and 300 m from twelve typical laying hen farms in the Ningxia Hui Autonomous Region of northwest China. Six antibiotics, seven heavy metals, ten mobile genetic elements (MGEs), and microbial community affected the ARGs profile in chicken dung and soil samples. Tetracycline antibiotic residues were prevalent in chicken manure, as were relatively high content of aureomycin during each culture period. Zinc (Zn) content was highest among the seven heavy metals in chicken feces. Chicken dung also enriched aminoglycosides, MLSB, and tetracycline ARGs, notably during brooding and high production. The farm had a minimal influence on antibiotics in the surrounding soil, but its effect on ARGs and MGEs closer to the farm (50 m) was stronger, and several ARGs and MGEs increased with distance. Manure microbial composition differed dramatically throughout breeding cycles and sampling distances. ARGs were more strongly related with antibiotics and heavy metals in manure than soil, whereas MGEs were the reverse. Antibiotics, heavy metals, MGEs, and bacteria in manure accounted 12.28%, 22.25%, 0.74%, and 0.19% of ARGs composition variance, respectively, according to RDA and VPA. Bacteria (2.89%) and MGEs (2.82%) only affected soil ARGs composition. These findings showed that heavy metals and antibiotics are the main factors affecting faecal ARGs and bacteria and MGEs soil ARGs. This paper includes antibiotic resistance data for large-scale laying hen husbandry in northwest China and a theoretical framework for decreasing antibiotic resistance.

[Distribution Characteristics of Antibiotics and Antibiotic Resistance Genes in Manure and Surrounding Soil of Poultry Farm in Ningxia].

Antibiotics and antibiotic resistance genes (ARGs) in livestock and poultry manure pose potential ecological risks. In order to understand the distribution characteristic of antibiotics and ARGs in manure and surrounding soils of poultry farms in Ningxia, the poultry manure and relative soil samples were collected from 12 layers of different poultry breeding farms. The compositions of antibiotics and ARGs in the samples were analyzed using UPLC-MS/MS and HT-qPCR. The results showed that:① tetracycline, aminoglycoside, and sulfonamide were the dominant antibiotics in poultry manure. The types and contents of antibiotics in poultry manure were different in different breeding periods. There were more types of antibiotics in the brooding period, the average content was high, and the initial stage showed the opposite trend. ② A small amount of antibiotics was detected in the surrounding soil only 20 m away from the poultry farm, and the poultry farm had little effect on the distribution of antibiotics in the surrounding soil. The content of quinolone in the soils with poultry manure application was significantly higher than that in the control and surrounding soil. ③ We detected 132-168 ARGs in poultry manure, and the number of aminoglycosides and tetracycline was higher. The relative abundance of ARGs in the rearing period was highest, and the initial stage showed the opposite trend. The total relative abundance of ARGs in the brooding period was highest, but the terminal period showed the opposite. There were 110 ARGs in poultry manure during all breeding periods. ④ There were 23-105 ARGs in the soils, and the number of aminoglycoside was highest, followed by multidrug ARGs. The poultry farm had a great effect on the number and relative abundance of ARGs in the surrounding soil. For example, the number and relative abundance of ARGs in the surrounding soil of poultry farms gradually decreased with the increase in the distance from the poultry farms. The number and relative abundance of ARGs in the soil with applied poultry manure were significantly increased; however, these values were lower than those in the soil 20 m away from the poultry farm. ⑤ ß-lactamases, aminoglycosides, and macrolide lincosamide-streptogramin B (MLSB) ARGs were all at risk of horizontal movement in manure, and chloramphenicol ARGs were at risk of horizontal movement in soil. Correlation analysis showed that the relative abundance of aminoglycoside, tetracycline, sulfonamide, ß-lactamase, and MLSB were not significantly correlated with their contents. ⑥ Different types of ARGs had related co-occurrence phenomena, such as the positive correlation between the relative abundance of ARGs in poultry manure, and aminoglycoside and ß-lactamases, MGEs, multidrugs and vancomycins. The relative abundances of ARGs in soil, aminoglycoside and tetracyclines, vancomycins, sulfonamides, and MLSBs; tetracyclines and MLSBs; etc., all showed a significant positive correlation. In short, the co-occurrence among the relative abundance of ARGs in soil was significantly stronger than that in poultry manure. These results could provide the theoretical basis for the site selection of poultry farms, the selection of antibiotic types and dosages for large-scale breeding of laying hens, and the application of poultry manure.

Environmental performance and international trade in China: The role of renewable energy and eco-innovation.

Renewable energy and green innovation can enhance environmental performance by encouraging international trade, as anticipated by the current theoretical framework. This study investigates how renewable energy and eco-innovation affect international trade and environmental performance using quarterly data series from 1981 to 2018 for China. The study applies a quantile-based autoregressive distributed lag model. The results indicate that environmental innovation and renewable energy are consistent with environmental quality, while trade openness and urbanization contribute to environmental degradation by stimulating CO2 emissions. In addition, the quantile causality test showed a bidirectional causality between renewable energy and CO2 emissions, trade openness and CO2 emissions, and urbanization and CO2 emissions. Additionally, the findings lend theoretical support for the formulation of environmentally protective policies to better understand the role of renewable energy in stimulating international trade, which eventually enhances environmental performance. Integr Environ Assess Manag 2022;18:813-823. © 2021 SETAC.

Effects of microplastics on humification and fungal community during cow manure composting.

The effect of microplastics (MPs) on the biological treatment of organic waste has been extensively studied, but little is known about the influence of different MPs on composting humification and the fungal community. In this study, PE, PVC, and PHA MPs were individually mixed with cow dung and sawdust and then composted. The results showed that different MPs had various influences on humification, and the humic acid to fulvic acid ratio of all MP-added treatments (0.44-0.83) was lower than that of the control (0.91). During the composting process, Ascomycota (26.32-89.14%) and Basidiomycota (0.47-4.78%) are the dominant phyla in all treatments and all microplastics decreased the diversity and richness of the fungal community at the thermophilic stage of composting. Exposure to MPs had an obvious effect on the fungal community at the genus level, and the addition of PHA and PE MPs increased the relative abundance of phytopathogenic fungi. LEfSe and network analysis indicated that MPs reduced the number of biomarkers and led to a simpler and more unstable fungal community structure compared to the control. This study has important implications for assessing microplastic pollution and organic waste disposal.

The Chinese automobile industry's research and development capability and innovative performance.

The Report of China's Automobile Industry Development 2016 points out that China's automobile industry faces increasingly fierce competition from global peers, and domestic automobile manufacturers shall continuously improve independent innovation and industry innovative performance. Automobile manufacturers' participation in distributed innovation and their research & development (R&D) capability play a key role in the growth of innovative performances of China's automobile industry. With development of China's automobile industry as the background, this study presents a theoretical framework of correlation of distributed innovation embedment, R&D capability and innovative performances of China's automobile industry from the microscopic perspective of single industry. Several hypotheses were proposed and then verified by empirical method. Specifically, 117 effective questionnaires were collected through non-probability sampling and analyzed quantitatively, followed by hypothesis test. The results clarify the working principles of the three dimensions of distributed innovation embedment influencing innovative performances of China's automobile industry and improvement of R&D capability of enterprises by distributed innovation. This study provides references to improvements of innovative performances of China's automobile industry.

Adipocyte factor CTRP6 inhibits homocysteine-induced proliferation, migration, and dedifferentiation of vascular smooth muscle cells through PPARγ/NLRP3.

NLRP3 and PPARγ play important roles in the development of atherosclerosis (AS). Studies have shown that PPARγ regulates the expression of NLRP3 in vascular diseases. In addition, the adipocyte factor CTRP6 can improve the activation of PPARγ in vascular diseases. However, the regulatory relationship between CTRP6, PPARγ, and NLRP3 in AS and its underlying mechanism have not been reported. Since proliferation, migration, and dedifferentiation of vascular smooth muscle cells (VSMCs) are key events in AS, in this study, we induced proliferation, migration, and dedifferentiation of VSCMs through homocysteine (HCY) to detect the specific effects of CTRP6, PPARγ, and NLRP3. Subsequently, CTRP6 was overexpressed and the PPARγ inhibitor GW9662 and agonist rosiglitazone were administered to HCY-induced VSCMs to investigate the mechanisms. The results show that the expression of CTRP6 decreased in HCY-induced VSMCs. In addition, CTRP6 overexpression inhibited the proliferation and migration of HCY-induced VSMCs, as well as cell cycle acceleration and dedifferentiation. Overexpression of CTRP6 increased HCY-induced PPARγ expression and inhibited NLRP3 expression. The addition of GW9662 and rosiglitazone further demonstrated that overexpression of CTRP6 inhibited HCY-induced VSMC proliferation, migration, and dedifferentiation through PPARγ/NLRP3 signaling. In conclusion, CTRP6 inhibited HCY-induced proliferation, migration, and dedifferentiation of VSMCs through PPARγ/NLRP3.

[Distribution Characteristics of Antibiotics and Antibiotic Resistance Genes in Manure and Surrounding Soil of Cattle Farms in Ningxia].

Livestock breeding intensively uses veterinary antibiotics in concentrated feeding operations to improve growth and control disease. Consequently, livestock and poultry manure is an important repository of antibiotics and antibiotic resistance genes (ARGs). To understanding the distribution of antibiotics and ARGs in manure and surrounding soils of cattle farms in Ningxia, cattle manure from five breeding periods (lactation, calving, growing, pre-fattening, and post-fattening periods) and comparative soil samples were collected from the largest beef-breeding area in Ningxia. The compositions of ARGs in the samples were analyzed by UPLC-MS/MS and HT-qPCR. The results showed that:① Tetracycline, quinolone, and sulfonamide were the dominant antibiotics in cattle manure. The content of antibiotics in the manure varied greatly between different breeding periods. High amounts of antibiotics were detected during the pre-fattening and lactation periods, and the lowest amounts were detected during the calving period. ② Quinolone and tetracycline were the dominant antibiotics in the soils, and the detection rate and content of quinolone were highest. The cattle farms did not affect the distribution of antibiotics in the surrounding soils. The content of quinolone and tetracycline in the soils with cattle manure application were significantly higher than control and surrounding soils. ③ We detected 79-142 ARGs in cattle manure, with aminoglycosides the most common form. The number and relative abundance of ARGs were highest during the growing period and lowest during the calving period. The dominant ARGs were tetQ, ermF, and tetO-01 across all the breeding periods. ④ There were 35-79 ARGs in the tested soils, and multidrug and aminoglycoside ARGs were dominant. The cattle farms did not affect the number and relative abundance of ARGs in the surrounding soils; however, manure application significantly affected the number and relative abundance of ARGs. ⑤ Sulfonamide and chloramphenicol ARGs are at risk of mobilization and horizontal transport. A correlation analysis showed that the relative abundances of aminoglycoside and tetracycline in cattle manure were significantly positively correlated with their contents. ⑥ Aminoglycoside, sulfonamide, chloramphenicol, and mobile genetic elements (MGEs) in manure were significantly or extremely significantly positively correlated with aminoglycosides and sulfonamides in the soils, whereas macrolides were negatively correlated with vancomycin. These results provide baseline data to inform controls on the variety and dosages of feed and veterinary drugs in cattle farms and the application of organic fertilizers in agriculture.

[Characteristics of heavy metals and bacterial community in manure and surrounding soil of cattle farm in Xiji, Ningxia, China]. / å®å¤è¥¿å‰åŽ¿å »ç‰›åœºç²ªæ±¡å’Œå‘¨è¾¹åœŸå£¤é‡é‡‘å±žåŠç»†èŒç¾¤è½ç‰¹å¾.

To understand the contamination status of heavy metals and bacterial community in the manure and surrounding soils of cattle farm in Ningxia, we collected cattle manure at different breeding periods (lactation, calf, growing, pre-fattening and post-fattening periods) and soil samples from the largest beef breeding area in the region by different distances, with the waste land far away as control. We measured heavy metal contents and the composition and diversity of bacterial community in manure and soil samples. The results showed that: 1) The contents of Cu, Zn, Cd, Pb and Hg in cattle manure were 33.8%-95.8% lower than the national average, while As content was 94.7% higher than the national average. During the breeding periods, the change tendencies of seven kinds of heavy metals in cattle manure were different. The contents of Cu, Cd, Hg and Cr of cattle manure in the pre-fattening period were the highest across all periods. The comprehensive pollution index of heavy metals in pre-fattening and post-fattening periods of cattle manure was highest in all periods. 2) The contents of Cu and Zn in the soils with cattle manure application were higher than control, and the content of Zn were significantly higher than surrounding soil samples. All single and comprehensive soil pollution indices of soil were safe. 3) During the breeding periods, Sequence, OTU and Chao1 index of cattle manure had no specific change. Sequence, OTU and Chao1 of soil with cattle manure application were higher than the soil around the farm. 4) The types of dominant phylum were less in the manure. The relative abundance of Firmicutes was the highest, followed by Bacteroidetes and Proteobacteria. The relative abundance of Firmicutes in the growing period was significantly lower than other breeding periods, and that of other phylum had little variation among periods. The cattle farm did not affect bacterial community in the surrounding soil. The cattle manure application didn't change the relative abundance of bacteria at the phyla level. The abundance of Gp, Gemmatimona, Lysobacte, Subdivision3_genera_incertae_sedis were significantly higher than control and surrounding soil. 5) Organic matter, pH, EC, total nitrogen, total potas-sium, Cd and As significantly affected bacterial diversity and component abundance in cattle manure. Soil pH, total phosphorus and Hg significantly influenced soil bacterial diversity and component abundance. On the whole, the effects of physicochemical properties in cattle manure and soil on bacterial community were more significant than heavy metals. Our results could provide scientific basis for selecting the variety and dosage of feed and veterinary drugs in local cattle farms, as well as the rational application of organic fertilizers.

Consideration of Thermo-Vacuum Stability of a MEMS Gyroscope for Space Applications.

Thermo-vacuum stability of the aerospace gyroscopes is one of the crucial issues in the harsh and remote environment of space. This paper reports a bias drift compensation algorithm for the MEMS (microelectromechanical systems) gyroscope with atmosphere package. This approach takes advantage of linear frequency-temperature dependence and linear amplitude-pressure dependence for self-compensation of the gyroscope bias drifts in real-time. The dependences were analyzed and evaluated by subjecting the gyroscope to a thermo-vacuum condition. The real-time self-compensation yielded a total bias error of 0.01°/s over a temperature range of 7-45 °C. A MEMS rate sensor was flown in space and the on-orbit data also verify the effectiveness of the approach.

A novel and sensitive electrochemical sensor based on nanoporous gold for determination of As(III).

Three-dimensional porous gold nanoparticles (NPG) were synthesized in situ on indium-doped tin oxide (ITO) substrates by a green and convenient one-step electrodeposition method to achieve super-sensitive As(III) detection. The introduction of NPG method not only greatly improves the electron transfer capacity and surface area of sensor interface but provides more active sites for As(III) enrichment, thus boosting sensitivity and selectivity. The sensor was characterized by scanning electron microscopy, energy dispersion spectroscopy, differential pulse anode stripping voltammetry (DPASV), and electrochemical impedance to evaluate its morphology, composition, and electrochemical performance. The wall thickness of NPG was customized by optimizing the concentration of electroplating solution, dissolved electrolyte, deposition potential, and reaction time. Under optimal conditions, the electrochemical sensor showed a wide linear range from 0.1 to 50 µg/L As(III), with a detection limit (LOD) of 0.054 µg/L (S/N = 3). The LOD is far below 10 µg/L, the recommended maximum value by the world health organization for drinking water. Stability, reproducibility, and repeatability of NGP/ITO were determined to be 2.77%, 4.9%, and 4.1%, respectively. Additionally, the constructed sensor has been successfully applied to determine As(III) in three actual samples, and the results are in good agreement with that of hydride generation atomic fluorescence spectrometry (AFS). Graphical abstract.

Effect of Gradient Heat Treatment on Microstructure and Properties of Cu-Al-Mn Shape Memory Alloy.

The columnar-grained Cu-Al-Mn shape memory alloys (SMAs), which have good shape memory properties and are prepared by a unidirectional solidification technique, were subjected to a gradient heat treatment under temperatures ranging from 100 to 450 °C. After this treatment, the microstructure, hardness, transformation temperature and shape memory properties of these samples could exhibit gradient changing trends, all of which were investigated by optical microscope, scanning electron microscopy (SEM), a Vickers microhardness tester, and a compression machine. The microstructure observation result shows that the acicular bainite-precipitated phase produces from scratch and then grows continuously with the increasing of the heat treatment temperature, finally presenting a graded distribution from one end section to another of the sample. The hardness tests give the samples results also increasing with temperature. Specifically, the change relationship between hardness and the treatment temperature mathematically satisfies dynamic function. In addition, it can be concluded from mechanical tests the compressive elastic-superelastic strain and strength of the samples show gradient variation features. Overall, our experimental investigation indicates that a gradient heat treatment is an effective way to conduct microstructure control or design for the Cu-Al-Mn SMAs, and their graded properties are mainly caused by the different fractions of the bainite phase producing in different local areas after the gradient heat treatment.

Precipitation is the main factor affecting the variation of foliar nitrogen isotope composition in two leguminous shrub species of northwestern China.

An increase in foliar nitrogen isotope composition (δ15N) with decreasing precipitation has been shown to occur widely in non-N2-fixing plant species. However, similar patterns have not been identified in N2-fixing species. Here, we tested the relationships of foliar δ15N with local environmental factors and leaf properties in two leguminous shrub species (Caragana korshinskii and Caragana liouana) sampled from 30 populations. Results indicated that the mean annual precipitation (MAP) primarily accounted for the variation of foliar δ15N in the two species. Further analysis revealed strong negative correlations between foliar δ15N and MAP within and across species. These results suggest that the foliar δ15N of leguminous shrub species also shift along precipitation gradients, which augments our understanding of the relationships between foliar δ15N and climatic factors.

Phosphorus addition changes belowground biomass and C:N:P stoichiometry of two desert steppe plants under simulated N deposition.

Many studies have reported that increasing atmospheric nitrogen (N) deposition broadens N:phosphorus (P) in both soils and plant leaves and potentially intensifies P limitation for plants. However, few studies have tested whether P addition alleviates N-induced P limitation for plant belowground growth. It is also less known how changed N:P in soils and leaves affect plant belowground stoichiometry, which is significant for maintaining key belowground ecological processes. We conducted a multi-level N:P supply experiment (varied P levels combined with constant N amount) for Glycyrrhiza uralensis (a N fixing species) and Pennisetum centrasiaticum (a grass) from a desert steppe in Northwest China during 2011-2013. Results showed that increasing P addition increased the belowground biomass and P concentrations of both species, resulting in the decreases in belowground carbon (C):P and N:P. These results indicate that P inputs alleviated N-induced P limitation and hence stimulated belowground growth. Belowground C:N:P stoichiometry of both species, especially P. centrasiaticum, tightly linked to soil and green leaf C:N:P stoichiometry. Thus, the decoupling of C:N:P ratios in both soils and leaves under a changing climate could directly alter plant belowground stoichiometry, which will in turn have important feedbacks to primary productivity and C sequestration.

PTEN promotes apoptosis of H2O2­injured rat nasal epithelial cells through PI3K/Akt and other pathways.

Chronic rhinosinusitis (CRS) is a form of chronic inflammation of the nasal cavity and paranasal sinus with multi­causal pathogenesis, including oxidative stress. Several lines of evidence have demonstrated that the phosphatase and tensin homolog gene (PTEN) can inhibit the activation of phosphoinositide 3­kinase (PI3K) to affect phosphorylation of Akt. Importantly, the PI3K/PTEN/Akt signaling pathway is associated with various types of tumors, chronic inflammatory diseases, and autoimmune disease through its regulation of cell growth, apoptosis, proliferation, and metabolism. This in vitro study aimed to investigate the role of PTEN and the relationship between PTEN and the PI3K/Akt pathway in nasal epithelial cells under oxidative stress. H2O2 treatment was applied to induce a cell injury model of oxidative stress in rat nasal epithelial cells. Cells were divided into control, H2O2, H2O2+PTEN, and H2O2+siPTEN groups. Cell viability was measured using the CCK­8 assay, and reactive oxygen species (ROS) levels and apoptosis rates were analyzed by flow cytometry (FCM). Oxidative parameters, including ROS, catalase (CAT), and malondialdehyde (MDA), were tested by enzyme­linked immunosorbent assay (ELISA). The expression of apoptosis­related genes and PI3K/Akt pathway was assayed by quantitative PCR (qPCR) and western blot. In H2O2­injured cells, oxidative stress, due to increased ROS levels and apoptosis rates, was induced, and PTEN aggravated the injury. The levels of both p­Akt and PTEN in H2O2­injured cells were positively correlated and higher than in control cells. Unknown regulatory protein(s) may exist in the PI3K/PTEN/Akt pathway or the PTEN and PI3K/Akt pathways may be two independent signaling pathways that have cross interactions.

[Hydrolysis and mechanism of wastewater contained protein using immobilized protein enzyme].

Protein-enzyme was immobilized on big-hole resin, activated charcoal and silica particles by a absorption method. This study focuses on effect of enzyme immobilization, thermal stability and hydrolysis efficiency of wastewater. The result of batch test show that the ratio of immobilized enzyme on activated charcoal, big-hole resin and silica particles was 61.95%, 37.85% and 20.31% respectively. The highest of thermal ability of activated charcoal, big-hole resin and silica particles was 18.68 mg/min, 21.48 mg/min and 3.6 mg/min respectively at pH 5.5. The total amino-acids of big-hole resin and activated charcoal immobilized enzyme after hydrolysis was respectively increased to 21.26 times and 14.6 times. The kind of amino-acid was increased from 14 to 16 kinds. The continuous-flow test result indicate that concentration of substrate in influent had significant effect on the hydrolysis rate of immobilized enzyme reactor. The reactor was able to gain hydrolysis rate of 80% for protein and 36.1% (VFA/COD%) for organic materials in the wastewater with a moderate concentration of protein (500 mg/L). The ethanol and acetic of volatile hydrolysis-mixture composition were 50.3% and 33.3% respectively.