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Rare-earth metal complexes have been used as catalysts for many types of reactions. However, the mechanism studies showed these various reactions basically proceeded with σ-bond metathesis of RE-E ...

Purpose The purpose of this paper is to propose a wheel/rail mixed lubrication model to study the water lubrication behavior of wheel/rail contact interface. Design/methodology/approach The numerical simulation method is applied in this paper. A deterministic mixed lubrication model considering surface roughness and transient state is established. The quasi-system numerical and finite difference method are used for numerical solution. The model is verified by comparing with the experimental data in the literature under the same conditions. Findings Under wet conditions, the change of train speed will change the lubrication state of the wheel/rail contact interface. With an increasing speed, the average film thickness and the film thickness ratio increase, while the adhesion coefficient, the contact load ratio and the contact area ratio decrease. When the creep ratio increases from 0% to 0.5%, the wheel/rail adhesion coefficient and subsurface stress increase sharply. With the increase of axle load, the average film thickness decreases and the adhesion coefficient increases. Practical implications This paper aims to improve the mixed lubrication theory by analyzing the characteristics of wheel/rail friction and lubrication, so as to provide some guidance and theory for train driving behavior. Originality/value Using the deterministic model, the lubrication state of the wheel/rail contact interface affected by various external factors and the adhesion behavior of wheel/rail progressive process from boundary lubrication to mixed lubrication are studied.

Exploring a rapid, reliable, and practical means to detect blockages and leakages in liquid pipelines and accurately locate their positions is of great importance in practical engineering applications. Here, we report a bubble motion-based triboelectric sensor (BM-TES) for detecting and locating the blockages and leaks inside a plastic tube. This simple-designed, environment-friendly, non-damaging sensor is composed of several ring-shaped Cu electrodes distributed on a polytetrafluoroethylene tube. The self-powered movement of the bubble under the action of buoyancy makes the inner wall of the tube change from the original solid-liquid phase to the gas-solid-liquid phase, which results in a short-term contact and separation between the liquid and the wall. Based on the fractional triboelectric effect of the liquid-solid contact, an obvious real-time stable voltage peak will be generated where the detection bubble passes. The obvious peaks of the open-circuit voltage with respect to time correspond with the electrode distribution. Then, the peaks can be utilized as a robust and sensitive indicator for detecting blockage and leakage, as the number of obvious peaks of the open-circuit voltage is directly related to the blockage and leakage location. The blockage and leakage in a fluid tube were successfully detected using the BM-TES with an accuracy of 10 cm. In addition, the BE-TES was able to detect the water flow velocity in the pipe. The experimental results showed that BM-TES can provide a new strategy and method for liquid tube monitoring and has great potential application value in related fields.

Background: Alzheimer’s disease (AD) has affected numerous elderly individuals worldwide. Panax notoginseng has been shown to ameliorate AD symptoms, and notoginsenoside R2 is a key saponin identified in this plant. Purpose: In the current study, we aimed to explore whether notoginsenoside R2 could improve the prognosis of AD. Methods: Herein, primary rat cortical neurons were isolated and they were treated with amyloid beta-peptide (A β) 25–35 oligomers. Cellular apoptosis was examined via flow cytometry and Western blotting. miR-27a and SOX8 mRNA expression levels were quantified by quantitative reverse transcription-polymerase chain reaction. Furthermore, the interaction between miR-27a and SOX8 was investigated by utilizing a dual-luciferase reporter assay. Finally, an AD mouse model was established to validate the in vitro findings. Results: Notoginsenoside R2 alleviated A β25-35-triggered neuronal apoptosis and inflammation. During this process, miR-27a expression was decreased by notoginsenoside R2, and miR-27a negatively modulated SOX8 expression. Furthermore, activation of SOX8 upregulated β-catenin expression, thus suppressing apoptosis and neuroinflammation. Conclusions: Our animal experiments revealed that notoginsenoside R2 enhanced the cognitive function of AD mice and inhibited neuronal apoptosis. Notoginsenoside R2 ameliorated AD symptoms by reducing neuronal apoptosis and inflammation, thus suggesting a novel direction for AD pharmacotherapy.

In this study, the wear failure behaviour of coated self-lubricating spherical plain bearings under different working conditions in the light-load and low-frequency range was studied using a swing wear life tester. The commercial GE17ES bearing was the main research object, and the wear state of the bearing was monitored in real time using torque and temperature rise signals. Furthermore, a scanning electron microscope and an energy dispersive X-ray spectroscope were adopted to analyse the wear failure mechanism of bearings. The results indicated that the friction torque and temperature rise signal changes were mainly divided into three stages, and the characteristics of similar changes could be maintained under different working conditions. Furthermore, at the end of the bearing life, the torque and temperature rise had abrupt changes almost at the same time, which indicated the occurrence of bearing failure. In general, the wear failure mechanisms of bearings included abrasive wear and adhesive wear. Moreover, fatigue wear and oxidation wear were under some conditions. The torque and temperature rise comprehensively reflected the service state of coated self-lubricating spherical plain bearings, which could be used as a physical criterion for determining bearing failure. These results had a strong prospect of engineering application, and were expected to provide a reference for determining the failure behaviour of multi-type coated self-lubricating spherical plain bearings in the future, and provided theoretical support for establishing relevant test standards.

Abstract Based on the energy flow theory of nonlinear dynamical system, the stabilities, bifurcations, possible periodical/chaotic motions of nonlinear water-lubricated bearing-shaft coupled systems are investigated in this paper. It is revealed that the energy flow characteristics around the equlibrium point of system behaving in the three types with different friction-paramters. (a) Energy flow matrix has two negative and one positive energy flow factors, constructing an attractive local zero-energy flow surface, in which free vibrations by initial disturbances show damped modulated oscillations with the system tending its equlibrium state, while forced vibrations by external forces show stable oscillations. (b) Energy flow matrix has one negative and two positive energy flow factors, spaning a divergence local zero-energy flow surface, so that the both free and forced vibrations are divergence oscillations with the system being unstable. (c) Energy flow matrix has a zero-energy flow factor and two opposite factors, which constructes a local zero-energy flow surface dividing the local phase space into stable, unstable and central subspace, and the simulation shows friction self-induced unstable vibrations for both free and forced cases. For a set of friction parameters, the system behaves a periodical oscillation, where the bearing motion tends zero and the shaft motion reaches a stable limit circle in phase space with the instant energy flow tending a constant and the time averaged one tending zero. Numerical simulations have not found any possible chaotic motions of the system. It is discovered that the damping matrices of cases (a), (b) and (c) respectively have positive, negative and zero diagonal elements, resulting in the different dynamic behavour of system, which gives a giderline to design the water-lubricated bearing unit with expected performance by adjusting the friction parameters for applications. Graphic Abstract

Fertilization can cause obvious shifts in nitrate-reducing community composition in agricultural ecosystems; however, little is known about the behaviors and functional characters of isolated nitrate reducers adapted to a specific environment. In this study, 849 nitrate-reducing bacteria were isolated from various fertilization treatments in a long-term paddy field experiment; the isolates were further characterized in functions with both culture-dependent and independent methodologies. The results showed that CK (no fertilizer) treatment had four genera with even relative abundance, whereas the other three treatments had their own predominant genera with Chromobacterium in nitrogen (N) fertilizer, Serratia in NPK (nitrogen, phosphorus, and potassium fertilizer) and Enterobacter in NPKC treatment (NPK plus rice straw). The isolates of Serratia and Enterobacter grew faster and produced significantly more nitrites than those of Chromobacterium and Burkholderia in the normal growth medium, suggesting that the dominant isolates from nutrient-rich environment, such as NPK and NPKC treatments, are better adapted to high nutritional conditions. On the contrary, the strains of Chromobacterium and Burkholderia possessed stronger nitrite production ability in comparison with the isolates of Serratia and Enterobacter in the diluted growth medium, indicating that the selected isolates from CK and N treatments have the capability to develop under nutrient-limiting conditions. Our results indicated that the behaviors and functions of nitrate reducers appears to be important in adapting to their dwelling habitats.

3D printing of hydrogels with high intrinsic mechanical performance has significant applications in many fields yet has been proven to be a fundamental challenge. Here, 3D printing of ultrahigh str...

Biological nitrogen (N2) fixation as a source of new N input into the soil by free-living diazotrophs is important for achieving sustainable rice agriculture. However, the dominant environmental drivers or factors influencing N2 fixation and the functional significance of the diazotroph community structure in paddy soil across a climatic gradient are not yet well understood. Thus, we characterized the diazotroph community and identified the ecological predictors of N2 fixation potential in four different climate zones (mid-temperate, warm-temperate, subtropical, and tropical paddy soils) in eastern China. Comprehensive nifH gene sequencing, functional activity detection, and correlation analysis with environmental factors were estimated. The potential nitrogenase activity (PNA) was highest in warm-temperate regions, where it was 6.2-, 2.9-, and 2.2-fold greater than in the tropical, subtropical, and mid-temperate regions, respectively; nifH gene abundance was significantly higher in warm-temperate and subtropical zones than in the tropical or mid-temperate zones. Diazotroph diversity was significantly higher in the tropical climate zone and significantly lower in the mid-temperate zone. Non-metric multidimensional scaling and canonical correlation analysis indicated that paddy soil diazotroph populations differed significantly among the four climate zones, mainly owing to differences in climate and soil pH. Structural equation models and automatic linear models revealed that climate and nutrients indirectly affected PNA by affecting soil pH and diazotroph community, respectively, while diazotroph community, C/P, and nifH gene abundance directly affected PNA. And C/P ratio, pH, and the diazotroph community structure were the main predictors of PNA in paddy soils. Collectively, the differences in diazotroph community structure have ecological significance, with important implications for the prediction of soil N2-fixing functions under climate change scenarios.

Inspired by the gas-trapped mechanism underwater of Argyroneta aquatica, we prepared a superhydrophobic yarn with a fiber network structure via a facile and environmentally friendly method. Attributed to the low surface energy, the superhydrophobic fiber network structure on the yarn is able to trap and transport bubbles directionally underwater. The functional yarn has good superhydrophobic and superaerophilic properties underwater to realize the directional transport of bubbles underwater without being pumped. We designed demonstration experiments on the antibuoyancy directional bubble transportation, which indicated the feasibility in the applications of gas-related fields. Significantly, on further testing, where the superhydrophobic yarn is put into a U-shaped pipe, we obtain a gas-siphon underwater with a high flux. The superhydrophobic fiber structure yarn can trap the gas underwater to enable the self-starting behavior while no manual intervention is used. The gas-siphon can convey gas over the edge of a vessel and deliver it at a higher level without energy input, which is driven by the differential pressure. The relationship between the differential pressure and the volume flux of transport bubbles is investigated. The experimental results show that the prepared superhydrophobic yarn has the advantages of good stability, easy preparation, and low cost in bubble continuous transportation underwater, which provides a novel strategy for the development and application of new technologies such as directional transportation, separation, exhaustion, and collection of gases in water.

Objective: To explore the clinical efficacy of Zhuang Medicine Lotus Acupuncture Cupping Stasis Therapy on patients with postherpetic neuralgia (PHN) and its action mechanism. Methods: 36 patients are randomly divided into Lotus Acupuncture Cupping Stasis Therapy group, pure cupping group and gabapentin group, with a total of five observation points for the first, fifth, tenth, fifteenth, and twentieth sessions of therapy (one session every three days). At each observation point, the venous blood of the patients is taken, and the contents of and changes in WNT3a, Frizzled8, β-catenin, IL-18, TNF-α, NR2B, NK-1 and SP are tested by ELISA, RT-PCR and WesternBlot, respectively. The VAS scores and safety of the patients in the three groups are compared. Results: With increased time spent in therapy, the VAS scores of patients in each group decreased gradually and there was a significant reduction in pain in patients in the Lotus Acupuncture Cupping Stasis Therapy group compared to the gabapentin and pure cupping groups (P Conclusions: Zhuang Medicine Lotus Acupuncture Cupping Stasis Therapy can significantly reduce the pain of PHN patients, with a good therapeutic effect, and it is worthy of clinical use.

Bioceramic scaffolds for repairing mandibular bone defects have considerable effects, whereas pore architecture in porous scaffolds on osteogenesis in specific structures is still controversial. Herein 6 mol% magnesium-substituted calcium silicate scaffolds were fabricated with similar porosity (∼58%) but different cylindrical pore dimensions (Ø 480, 600, and 720 μm) via digital light processing-based three-dimensional (3D) printing technique. The mechanical properties, bioactive ion release, and bio-dissolution of the bioceramic scaffolds were evaluated in vitro, and the facilitation of scaffolds on bone formation was investigated after implanting in vivo. The results showed that as the pore dimension increased, the scaffolds indicated similar surface microstructures, but their compressive strength was enhanced gradually. There was no significant difference in vitro bio-dissolution between the 480 and 600 μm groups, whereas the 720 μm group showed a much slower dissolution and ion release. Interestingly, the two-dimensional/three-dimensional (2D/3D) micro-CT reconstruction analysis of rabbits' mandibular bone defects model showed that the 600 μm group exhibited evidently higher ratio of the newly formed bone volume to total volume (BV/TV) and trabecular number (Tb. N) values and lower ratio of the scaffolds residual volume to total volume (RV/TV) compare to the other two sizes. Furthermore, the histological analysis also revealed a considerably higher new bone ingrowth rate in the 600 μm group than the other two groups at 4-12 weeks post-implantation. Totally, it is proved from these experimental studies that the DLP-based accurately fabricated calcium (Ca) silicate bioceramic scaffolds with appropriate pore dimensions (i.e., 600 μm in pore size) are promising to guide new bone ingrowth and thus accelerate the regeneration and repair of cranial maxillofacial or periodontal bone defects.

Despite many years of research, the current-carrying friction interface still strongly depends on the lubricating film between the friction pairs, because this film can reduce the probability of arc occurrence. However, this film has poor conductivity, cannot self-heal, and is prone to be greasy, which reduces the efficiency of current conduction, which seriously affects the contact status. In order to solve this problem, graphite materials with excellent lubricating properties and electrical conductivity are used to make current-carrying friction materials. Graphite and graphite-based composite materials are the most widely used current-carrying friction materials in various industries. Graphite has excellent lubricity, conductivity, and high temperature resistance to steel and many other metal materials. However, with the passage of time, due to the continuous deterioration of the application conditions and the environment, such as arc under high current density, spark phenomenon, severe mechanical wear under high load, etc., the lubricating film is destroyed, which greatly weakened the performance of protecting friction pairs. Therefore, improving the working stability of the current-carrying friction pair is the key to ensuring that the contact pair does not spark. In this review, we mainly discuss how to improve the stability of the current-carrying friction system, reduce the wear of the current-carrying friction system, and thereby extend the service life of the current-carrying friction material. At first, we discussed the latest research progress of current-carrying friction from the electrical properties, contact resistance, thermal effect, and arc of current-carrying friction materials to tribological characteristics. Secondly, the influence of contact resistance parameters and structural function parameters on the wear life of current-carrying friction pairs is discussed. The current research status of current-carrying performance and tribological performance of current-carrying friction pairs under the coupled effects of temperature field and current field is discussed. It is necessary to combine experiment, theory, and simulation to study the temperature field of the current-carrying friction pair, especially the influence of complicated conditions such as oil and dust on the friction performance of the current-carrying. Thirdly, the influence of arcing, sparking, and dynamic characteristics on the friction performance of the current-carrying friction system is reviewed. At the same time, the prediction model of current-carrying friction and wear should be studied systematically to detect current-carrying friction and wear online. Finally, it introduces in detail that new current-carrying friction materials are developing in the direction of tissue functionalization and structural composite.

Hypothesis Hydrogels are widely used in the field of water lubrication and friction, such as artificial cartilage, because of their good wettability and flexibility. Moreover, compared with single network hydrogel, Triple-network (TN) hydrogel has higher fracture stress. Therefore, the research and preparation of a TN hydrogel with good mechanical properties and friction properties will be of great help to the improvement and application of hydrogel properties. Experiments A chemical-physical crosslinked triple-network (TN) hydrogel was prepared using PVA, PVP and AA as raw materials. By controlling the content of Zn2+ in TN hydrogel, conducting tension-compression test and friction test, we studied the effect of Zn2+ on the mechanical properties and friction properties of hydrogel. Findings The results showed that TN hydrogel had the best mechanical properties when the content of Zn2+ was 0.4 g. The fracture stress was 1.87 MPa, the strain rate was 175%, and the compressive stress was 3.5 MPa under 80% compressive deformation. At room temperature, TN hydrogel had good self-healing property and could maintain a high mechanical recovery rate, with a maximum recovery rate of 87%. The friction test results manifested that the hydrogel had a low friction coefficient, and the minimum friction coefficient was 0.15. The PVA/PVP/PAA-TN hydrogel prepared by this method has widened the application scope of hydrogel, making it more applicable in the field of high friction coefficient and mechanical properties.

Nitrous oxide reduction is a pivotal process of nitrogen transformation regarding to global warming and ozone depletion, but little is known about the ecological distribution of nitrous oxide reducing communities and their determining factors. In total, 131 agricultural upland soil samples, including quaternary red clay soil (QRC), tertiary red stone soil (TRS), alluvial soil (AS) and black soil (BS) were collected in this study. Typical nitrous oxide reducers (nosZI) were sequenced on an Illumina Miseq platform. The results showed that although different types of soils displayed distinctive soil properties, 515 out of 994 OTUs were common species shared by all the four soil types, moreover, these common OTUs took 96–99% of the relative abundance of the total nosZI-containing population in different soil types. In contrast, unique nosZI-containing species which appeared in one specific type of soil were minimal. Furthermore, copiotrophic taxa including Bradyrhizobiaceae, Rhodospirillaceae and Phyllobacteriaceae were the dominant common nosZI-containing communities. These results indicated that nosZI-containing denitrifiers were homogenously distributed among different agricultural soils, which may be closely related to the intensive agricultural practices under long-term crop cultivation. Even though, the relative abundance of most of the common OTUs, especially the high abundant ones, showed significant variations among the soil types. Collectively, our results suggested that the nosZI-containing soil microorganisms could be homogenized and enriched in agricultural soils with the agricultural practices acting as major potential drivers, whereas soil distinctive properties resulted in significant shifts in the relative abundance of common nosZI-containing denitrifying species and the presence of a small number of unique communities with low abundance.

Although cumulative N2O emissions are greater in the winter fallow season than in the rice-growing period, the mechanisms by which the emissions affect fallow paddy fields remain unclear. We aimed to identify N2O flux characteristics and illustrate how key nirS-, nirK- and nosZ-containing denitrifiers affect N2O emission levels in acidic fallow paddy soil. Five water-filled pore space (WFPS) levels were set at 25%, 50%, 75%, 100% and 125%, respectively. During the 48-h-long, high-flux incubation period, the N2O flux was the highest in soil samples with 75% WFPS, followed by those with 100% WFPS. The size of nirS-containing denitrifier community was more sensitive to the shifts in soil moisture and showed a stronger correlation with N2O flux than that of nirK-containing denitrifiers, whereas higher N2O concentrations induced an increase in the levels of nosZ-containing bacteria. After incubation for 48 h, nirK- and nosZ-denitrifying bacterial composition varied remarkably under 50%, 75%, and 100% WFPS treatments. However, the composition of nirS-containing denitrifying bacterial community gradually varied with an increase in soil moisture from 25% to 100% WFPS. Certain dominant OTUs of nirK- nirS- and nosZ-containing denitrifiers were highly abundant, especially under treatments of 50%, 75% and 100% WFPS, which were closely associated with the N2O flux. Thus, nirK, nirS and nosZ-containing denitrifiers respond to soil moisture differently, and enriched species might mainly be involved in controlling N2O flux in fallow paddy soils via denitrification, while the abundance of nirS-containing denitrifiers might affect N2O emission levels more significantly than that of nirK-containing denitrifiers.

Biochar amendment can reduce CH4 emissions from paddy soils. However, little is known about how the soil microbial communities associated with paddy soil CH4 emissions respond to biochar aging after biochar amendment. In this study, we examined the effects of biochar on CH4 emissions, soil properties, and abundance/community composition of methanogens and methanotrophs in a double rice cropping system from 2012 to 2016. Straw-derived biochar was applied once in 2012 at 24 and 48 t ha−1. Biochar application decreased the annual CH4 emissions by 20–51%. Biochar increased the abundances of both methanogens and methanotrophs, with a larger increase of methanotrophs than methanogens in the first year, mainly caused by the increases in soil dissolved organic carbon, NH4+-N, and porosity. Biochar suppressed the abundance of methanogens and had little effect on the methanotrophs in the following three years, probably due to the increased soil porosity. Eventually, the ratios of abundance of methanogens to methanotrophs decreased by 11–31% in each of the four years and were positively correlated to CH4 emissions. Biochar addition increased the relative abundances of Methanocella and Methanospirillum and reduced those of Methanoregula and Methanosaeta for methanogens, while it increased the proportion of the basophilic methanotrophs Methylomicrobium and decreased that of Methylocaldum in the growing season 2014. Our results demonstrate that biochar aging greatly alters the responses of abundances and community compositions of soil methanogens and methanotrophs to biochar addition. The reduction of CH4 emissions owing to biochar in the long run was probably mainly due to the lesser suppression of abundance and activity of methanotrophs compared with methanogens.

The treatment of neural deficiency after cerebral infarction is challenging, with limited therapeutic options. The transplantation of mesenchymal stem cells (MSCs) to the ischemic penumbra is a potential therapeutic approach. In the present study, a cerebral infarction model was generated by performing middle cerebral artery occlusion (MCAO) in SD rats. The expression of CXCR4 increased, and the number of MSCs migrating to the peri-infarct area was higher in rats transplanted with preconditioned MSCs than in rats transplanted with untreated MSCs. The rate of apoptosis, as evaluated by TUNEL staining and immunoblotting assays, was reduced in rats receiving preconditioned MSCs. A significant amelioration of neural regeneration and improved neurological function were observed in rats injected with preconditioned MSCs compared with those injected with untreated MSCs. However, the application of an siRNA targeting CXCL12 significantly inhibited the protective role of preconditioned MSCs against apoptosis and promoted the migration of MSCs to the ischemic area, leading to impaired neuronal regeneration and limited recovery of neuronal function. Hypoxic preconditioning of MSCs prior to transplantation suppressed apoptosis and increased their migration abilities, leading to the promotion of neuronal regeneration and improvement in neural function after transplantation. This preconditioning strategy may be considered as a potential approach for the modification of MSCs prior to cell transplantation therapy in patients with cerebral infarction. SIGNIFICANCE OF THE STUDY: We found that hypoxic preconditioning of MSCs improved their ability to promote neuronal regeneration and the recovery of neuronal function. Moreover, we showed that CXCR4 inhibited apoptosis, improved cell homing, and promoted neuronal differentiation, without influencing angiogenesis. Our study provides a relatively safe preconditioning method for potential use for cell transplantation therapy in ischemic cerebral infarction. The results presented here will facilitate the development of novel strategies and techniques to improve the tolerance and migration ability of transplanted cells for the treatment of cerebral infarction sequelae.

Composite insulators with superhydrophobic coatings can ensure the safe operation of railways, electricity and telecommunication systems. A robust Mg(OH)2/epoxy resin superhydrophobic coating for composite insulators is reported. The coating is fabricated by a simple method, and the water contact angle reaches its maximum value of 155° at the stearic acid loading of 0.285 g. The superhydrophobic property is controlled by different amounts of stearic acid, which influence the surface roughness of the coating. Additionally, the coating shows mechanical stability, chemical durability and a self-cleaning property, allowing it to be stored in water for more than 20 days. In consideration of the above-mentioned advantages, these characteristics make the composite insulators with this coating a better value than the commercial composite insulators, which is of great benefit to global electricity issues.

In order to reduce the possibility of cotton fabrics causing fire and improve the waterproofness of the fabric, a superhydrophobic flame retardant (SFR) coating was fabricated on cotton fabric using a simple two-step process. Firstly, the fabric was pretreated with diammonium phosphate solution, and then H-ZrO2 (ZrO2 which is modified by hexadecyltrimethoxysilane) was adhered to the surface of the fabric using polydimethylsiloxane. The morphology, chemical composition and element distribution of the coating were detected and characterized using SEM, ATR-FTIR, XPS and EDS. In addition, the flame-retardant properties of the coated fabric samples were tested using thermal stability and vertical burning tests. Superhydrophobic fabric was tested and evaluated by subjecting the coated fabric to abrasion, washing, acid–base soaking and ultraviolet irradiation tests, and the contact angles of the sample before and after the test were investigated. The results showed that the coated fabric has a strong hydrophobic ability. When the H-ZrO2 content in the solution is 0.8 g, the coated fabric has a maximum contact angle of 154°. Moreover, the coating has good wear resistance, acid and alkali resistance and UV resistance. Importantly, the modified fabric shows excellent flame-retardant performance.

Warming strongly stimulates soil nitrous oxide (N2O) emission, contributing to the global warming trend. Submerged paddy soils exhibit huge N2O emission potential; however, the N2O emission pathway and underlying mechanisms for warming are not clearly understood. We conducted an incubation experiment using 15N to investigate the dynamics of N2O emission at controlled temperatures (5, 15, 25, and 35°C) in 125% water-filled pore space. The community structures of nitrifiers and denitrifiers were determined via high-throughput sequencing of functional genes. Our results showed that elevated temperature sharply enhanced soil N2O emission from submerged paddy soil. Denitrification was the main contributor, accounting for more than 90% of total N2O emission at all treatment temperatures. N2O flux was coordinatively regulated by nirK-, nirS-, and nosZ-containing denitrifiers but not ammonia-oxidizing archaea or ammonia-oxidizing bacteria. The nirS-containing denitrifiers were more sensitive to temperature shifts, especially at a lower temperature range (5 to 25°C), and showed a stronger correlation with N2O flux than that of nirK-containing denitrifiers. In contrast, nosZ-containing denitrifiers exhibited substantial variation at higher temperatures (15 to 35°C), thereby playing an important role in N2O consumption. Certain taxa of nirS- and nosZ-containing denitrifiers regulated N2O flux, including nirS-containing denitrifiers affiliated with Rhodanobacter and Cupriavidus as well as nosZ-containing denitrifiers affiliated with Azoarcus and Azospirillum. Together, these findings suggest that elevated temperature can significantly increase N2O emission from denitrification in submerged paddy soils by shifting the overall community structures and enriching some indigenous taxa of nirS- and nosZ-containing denitrifiers. IMPORTANCE The interdependence between global warming and greenhouse gas N2O has always been the hot spot. However, information on factors contributing to N2O and temperature-dependent community structure changes is scarce. This study demonstrated high-temperature-induced N2O emission from submerged paddy soils, mainly via stimulating denitrification. Further, we speculate that key functional denitrifiers drive N2O emission. This study showed that denitrifiers were more sensitive to temperature rise than nitrifiers, and the temperature sensitivity differed among denitrifier communities. N2O-consuming denitrifiers (nosZ-containing denitrifiers) were more sensitive at a higher temperature range than N2O-producing denitrifiers (nirS-containing denitrifiers). This study's findings help predict N2O fluxes under different degrees of warming and develop strategies to mitigate N2O emissions from paddy fields based on microbial community regulation.

For liquid–porous material interactions (LPMI), three variational principles are developed in Biot's theory of porous materials in association with Darcy's Law. First one takes solid acceleration, and fluid velocity, acceleration, pressure with time derivative as five variables, while second and third, respectively, have three and two variables when Darcy's Law used as variational constraint reducing variables. These principles provide a means to derive approximate solutions and finite-element (FE) models for LPMI. Each LPMI element includes fluid and solid together with it being no longer necessary to distinguish fluid domain from solid. Examples illustrate applications to establish FE model for numerical solutions of LPMI. Solution of a one-dimensional problem reveals that LPMI behaves a coupled-frequency separation measured by a defined-coupling factor. Dynamic response explores coupled-dynamic absorber mechanism in LPMI system, from which it is found that the external force at fluid does not contribute to fluid response but fully absorbed by solid local resonance if the force frequency equals the solid natural frequency; while in the reverse case when the force frequency equals the fluid one, the force at solid does not produce the solid response but fully absorbed by fluid local resonance. New findings with defined LPMI coupling factor provide guidelines for designing LPMI system with expected dynamic behaviour meeting engineering requirements.

IntroductionWe aimed to determine the effects of Zhuyu Annao (ZYAN) prescription on hippocampal neuronal apoptosis and cognitive disorder (CD) in ischemic brain injury (IBI).Material and methodsThe improved Rice-Vannucci method was used to prepare a rat model of IBI. Rats in the ZYAN prescription group were intragastrically administered 12.50 g/kg of ZYAN prescription 4 h after modeling; rats in the mock surgical group (MSG) and model group (MG) were administered an intraperitoneal injection of the same volume of normal saline twice daily.ResultsCompared with MG, the area of cerebral infarction, pathological changes, neuron apoptosis index, and neurodeficit score were significantly reduced in the ZYAN prescription group (P < 0.05). Morris water maze test showed that in the ZYAN prescription group, incubation period was significantly shortened and the number of platform crossings was significantly increased (P < 0.05). Furthermore, the rats in the ZYAN prescription group showed significantly reduced protein and mRNA expressions of cleaved caspase-3, Bax, p-53, and p38 mitogen-activated protein kinase (MAPK) in the hippocampus, whereas the protein and mRNA expressions of Bcl-2 were significantly increased (P < 0.05).ConclusionsZYAN prescription reduced the area of cerebral infarction, attenuated neuronal apoptosis, and alleviated CD in the rats with IBI. The beneficial effect of ZYAN prescription in IBI may be mediated via the inhibition of the p38 MAPK signaling pathway and caspase-3 cascade reaction.

A superamphiphobic coating is usually prepared via a reduction reaction and then deposited onto the surface of the substrate. This technology is difficult to control and achieve high bond strength, which easily leads to powder shedding. To overcome this issue, electroplating technology is usually preferred for preparing adhesion coatings. However, the coating prepared using this method is usually suitable only for hard steel substrates, and not for soft substrates such as carbon brushes. Herein, we demonstrate an air spray technology for preparing anti-greasy and conductive superamphiphobic graphite-1H,1H,2H,2H-perfluorooctyltrichlorosilane–SiO2 (GPS) coatings suitable for both soft substrates (carbon brushes) and hard substrates (collector rings). The sheet resistance of the coating with 10% graphite content is 4.8 × 10−3 Ω □−1 for a 10 μm thin coating, corresponding to a resistivity of 4.8 μΩ cm. More importantly, the prepared coating has excellent liquid repellency, such as water, rapeseed oil and n-hexane. In addition, the coating has excellent anti-greasy and mechanical properties, which provide a brand-new solution for the greasy pollution in the engineering field. These advantages will enhance the application of superamphiphobic GPS coating in the fields of hydropower, wind power and transportation, and so on.

High yields and environment-related issues because of over-fertilization in rice (Oryza sativa L.) production is a major concern in China. Partial replacement of mineral fertilizer (MF) with organic matter is considered a win–win approach for resource-saving and environmentally friendly rice production. Here, we examined the effects of reduced MF and in situ crop residue on the rice yield and soil fertility in the long term. A 27-year field experiment (a randomized block design with three replicates) in subtropical China was conducted to test the feasibility of the substitution in a double rice paddy ecosystem. The treatments were CT (no fertilizer application considered as control), NPK (mineral fertilizer N, P, and K), and RFC (reduced MF and in situ crop residue to supplement the reduced NPK dose). The crop residue included half of the rice straw and green manure contents, which were retained in situ in the RFC treatment. The RFC maintained the same rice yield and soil fertility levels as NPK. In general, soil organic carbon (SOC) and total nitrogen (TN) content in RFC increased by 10.3% –20.8%, and 7.5% –28.0%, respectively, than that in NPK from the 5th to the 25th years. There was no significant difference in the content and net accumulation of SOC, TN, and TP and soil available nutrients between the RFC and NPK treatments after 25 years. The average annual yields were 9690 and 9872 kg ha−1 for the NPK and RFC treatments, respectively. There was no difference in the yield of the first, second, and annual rice crops between RFC and NPK in most years (six of the fifty-four seasons showed a significant difference). RFC increased the partial factor productivity (PFP), agronomic efficiency (AE) of MF, and yield stability (CV) (p

Cerebral ischemia is the most common cause of hippocampal neuronal death and the most prevalent cause of stroke with high mortality rate. Ferroptosis has been suggested to affect the role of hippocampal neurons. This study explores the influence of lentivirus infection-induced ferritin overexpression in hippocampal neuronal injury and death through simulations in August Copenhagen Irish rat models. Twenty-four-hour cerebral ischemia-reperfusion injury was induced in the rats after 90-min middle cerebral artery occlusion (MCAO). Ferritin overexpression was induced through lentivirus infection. The Morris Water Maze (MWM) test and tau hyperphosphorylation test were performed on hippocampal neurons to establish a MCAO model. The effect of ferritin overexpression on hippocampal neuronal death was evaluated using hematoxylin-eosin staining and annexin V/propidium iodide flow cytometry. The MWM test revealed that MCAO modeling decreased the cognitive and locomotor capacity of the rats, whereas ferritin overexpression partially reversed the effect of MCAO. In addition, the hyperphosphorylation of tau caused by MCAO was reduced by ferritin. Pathogenic changes, impaired viability, increased apoptosis, and elevated caspase-9 cleavage in hippocampal neurons were clearly recovered by ferritin. Moreover, robust reactive oxygen species production and glutathione consumption, which was induced by MCAO modeling, were ameliorated by ferritin. Furthermore, two key modulators of ferroptosis, p53 and SLC7A11, were demonstrated to be upregulated by MCAO modeling and downregulated by ferritin. Ferritin reduction is essential for cerebral ischemia-induced hippocampal neuronal ferroptosis mediated via p53 and SLC7A11.

Alzheimer's disease (AD), the most prevalent representation of dementia, is a neurodegenerative disease resulting from the degenerative disturbance of the central nervous system. Previous studies have indicated that miR-107 is reduced in the brain neocortex of patients with AD; however, its underlying mechanism is not clear. Therefore, the objective of this study was to explore the question of whether miR-107 participates in AD development. The study confirmed that the miR-107 expression levels were dramatically decreased in patients with AD and in beta-amyloid (Aβ) (Aβ)-treated SH-SY5Y cells compared with control groups. Upregulation of miR-107 reversed the inhibitory role of Aβ on cell proliferation and viability. In addition, miR-107 upregulation also ameliorated the Aβ-induced inflammation and apoptosis of SH-SY5Y cells. Furthermore, using bioinformatic prediction, dual-luciferase reporter assay (DLRA), quantitative polymerase chain reaction (qPCR), and Western blot (WB), miR-107 was confirmed to reduce the expression level of FGF7, and it subsequently deactivated the FGFR2/PI3K/Akt pathway. Moreover, FGF7 overexpression counteracted the role of miR-107 in the viability, proliferation, inflammation, and apoptosis of Aβ-induced SH-SY5Y cells.

Tree species and seasonal change influence N2O flux and microbial communities, but the mechanisms are unclear. We studied N2O flux in soils planted with slash pine and oil-seed camellia trees. We sampled on typical days of the four seasons. We tested whether N-cycling communities respond more to tree species or seasonal change. We assessed how tree species affect N2O flux. We used qPCR and RFLP to determine abundance and community composition of amoA-containing bacteria (AOB) and archaea (AOA), and denitrifiers that contain the narG, nirK, nirS, and nosZ genes. N2O flux rate and soil characteristics varied significantly between forest soils and sampling seasons. Abundance of all detected genes, but not of the nirS gene, was significantly affected by tree species. Differences in gene abundance between days in different seasons were found only for narG, nirK, and nosZ. Functional microbial community composition in the soil varied between the tree species for most of the genes studied, but varied, not significantly, slightly among sampling days. Differences in the abundance and community composition of nitrifiers and denitrifiers between tree species depended on soil concentration of NH4+, NO3−, and dissolved organic carbon (DOC). N2O flux rate was affected by community composition, but not abundance of nitrifiers and denitrifiers. Temperature, NO3−, and DOC concentrations significantly affected N2O flux. Tree species influenced N2O flux more than seasonal change, by altering community composition and environmental factors rather than nitrifier/denitrifier abundance.

Composite insulators with a superhydrophobic coating can tremendously improve the reliability and stability of transmission line systems and railway systems; thus, they play a crucial role in global electricity issues and power systems. However, the majority of superhydrophobic coatings for composite insulators suffer from weaknesses, such as poor mechanical stability and complicated and toxic preparation processes. To improve these defects, a multifunctional, micro-nanoscale SiO2/epoxy resin superhydrophobic coating for composite insulators was created. The coating maintained excellent superhydrophobicity through a bending experiment, a twisting test, a knife-scratch, a durability test, a pH test and UV light treatment. Moreover, it also performed well in the areas of anti-icing, high thermal stability (300 °C), self-cleaning and antifouling. In view of abovementioned advantages, composite insulators with the proposed superhydrophobic coating show great potential for the national economy and power industry.