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Perovskite type hydrides have emerged as a focal point in hydrogen storage applications as potential candidates in recent years. However, the currently synthesized perovskite hydrogen storage materials suffer from high hydrogen desorption temperatures and unstable reactions. To identify promising perovskite hydrogen storage materials, this study explores the hydrogen storage properties of XCrH 3 (X = Na, K) and KYH 3 (Y Mo, W) based on first-principles (FPs) calculations. The results indicate that NaCrH 3 and KCrH 3 exhibit half-metallic properties, while KMoH 3 and KWH 3 are metallic materials with high hydrogen storage safety. Mechanical property analysis reveals that NaCrH 3 exhibits the highest hardness, indicating better stability for hydrogen storage. Thermodynamic analysis shows that KCrH 3 has a lower hydrogen desorption temperature than the other three compounds, with NaCrH 3 having the second-lowest. The gravimetric hydrogen storage capacities of NaCrH 3 , KCrH 3 , KMoH 3 , and KWH 3 are 3.85 wt%, 3.21 wt%, 2.19 wt%, and 1.34 wt%, respectively. Overall, NaCrH 3 demonstrates superior gravimetric hydrogen storage capacity, stability, and safety, making it a promising candidate for new perovskite type hydrogen storage materials. • All four compounds are magnetic materials and stable. • NaCrH 3 exhibits the highest hardness with superior stability in hydrogen storage and release reactions. • NaCrH 3 has a higher gravimetric hydrogen storage capacity and a lower evolution temperature. • KWH 3 is a ductile material, and the other three are brittle materials. [ABSTRACT FROM AUTHOR]

MgB 2 has a wide range of applications as a crucial superconducting material in fields such as electronics and communications, but its weak mechanical properties limit its use in extreme environments such as high pressure. Therefore, this article explores the enhancement mechanism of the mechanical properties for MgB 2 by substituting Mg sites with Nb element based on first principles. After substitution, NbB 2 has better thermodynamic stability, and the introduction of Nb-d state enhances light absorption. In terms of mechanics, due to the higher electron accumulation density in the Nb–B bond and a shorter bond length (2.451 Å), the atomic interactions become tighter and stronger. As a result, both elastic constants and modulus are enhanced, exhibiting high stiffness, high compression resistance, etc. The spatial distribution of 3D elastic anisotropy is closer to a spherical shape and the universal anisotropy index (A U ) tends to approach 0, which indicates the mechanical properties in all directions are more consistent, making it easier to predict and control. Meanwhile, the elastic modulus rises smoothly with increasing hydrostatic pressure and is not affected by lattice compression at low hydrostatic pressure. The change rate of B–B bond length is 6.8 % at 100 GPa, which becomes the main reason for the enhancement of mechanical properties. The article provides a theoretical foundation for the preparation of superconductors with excellent mechanical properties under extreme conditions. [ABSTRACT FROM AUTHOR]

Root border cells (RBCs) and their mucilage are considered to play an important role in protecting root tip from aluminum (Al) toxicity, but their interactions with silicon (Si) under Al stress still remain unclear. Here, we investigated the effect of Si on the formation of RBCs under Al stress and the related detoxification mechanism in hydroponically grown rice (Oryza sativa L.). The results showed that Si could prevent the separation of RBCs from each other by increasing the degree of pectin methylesterification in root tip cell wall, thereby keeping more RBCs around the root tip. Also, Si maintained the viability of RBCs, increased the amount of mucilage, and reduced the content of total Al and free Al in root tips. Moreover, the RBCs accumulated more Al and Si simultaneously than root tip in the Al treatments with Si supply. Overall, these results indicated that Si reduced the toxicity of Al to RBCs through formation of Si–Al complex on the RBCs, thereby improving the viability of RBCs and promoting the secretion of mucilage. Concomitantly, Si, RBCs and their mucilage could form a protective sheath at the root tip, which prevented Al from diffusing into the root tip, thereby alleviating Al toxicity in rice root tips. [Display omitted] • Si kept more RBCs around the root tip under Al stress. • Si improved the viability of RBCs and promoted the production of mucilage. • The formation of Si–Al complex on the RBCs reduced the toxicity of Al to root tip. • A protective sheath formed by RBCs and mucilage prevented Al from entering root tip. [ABSTRACT FROM AUTHOR]

The layered structure of GeS exhibits commendable thermal stability and holds significant promise in the realms of optoelectronics and ion batteries. But its application is limited as dilute magnetic semiconductor. Therefore, this study delves into the impact of 3d transition metal (TM = V, Cr, and Mn) doping on the magnetic and optical characteristics of two-dimensional GeS monolayer through a first-principles calculation method grounded in density functional theory. The findings elucidate that all doping systems lead to a reduction in the band gap, with the V-doped system exhibiting the most significant diminishment. After doping process, magnetic coupling emerges between the electrons in the TM-3d state and those in the S-3p state, resulting in the manifestation of magnetic semiconductor characterized by magnetic moments of 3 μ B , 4 μ B , and 5 μ B , respectively. Comparative analysis with the pristine GeS monolayer, it reveals enhancements in optical absorptivity and refractive index within both the infrared and visible spectra of the doped systems. Notably, the V-doped system showcases superior optical properties due to its narrower band gap, facilitating more efficient electron transitions to the conduction band. Consequently, TM (TM = V, Cr, and Mn)-doped GeS monolayer hold promising potential in the realms of spintronics and optoelectronics. [ABSTRACT FROM AUTHOR]

Efficient photocatalytic water splitting is of holds paramount importance in addressing contemporary energy and environmental challenges. The emergence of symmetry-deficient Janus two-dimensional materials has opened new avenues for advancing the field of photocatalytic hydrogen production. Using first-principles calculations, we investigated a novel Janus Zn 2 XY (X = S, Se; Y Se, Te; X≠Y) monolayer. The results demonstrate exceptional structural stability and favorable characteristics for water splitting, including direct band gaps and optimal band edge alignment. Spatially separating band edge states and the intrinsic vertical electric field effectively suppress the recombination rate of photogenerated electron-hole pairs. Strain engineering enhances the monolayer's capacity for visible light absorption. Furthermore, All Janus monolayers exhibit an impressive electron mobility of 103 cm2/V/s, with Janus Zn 2 STe and Zn 2 SeTe monolayers reaching 16.28% and 16.34% Solar-to-hydrogen (STH) efficiencies, respectively. These findings showcase the superior performance of Janus Zn 2 XY in water splitting and guide future experimental endeavors. [Display omitted] • Janus Zn 2 XY (X = S, Se; Y Se, Te; X≠Y) shows promise for water splitting. • They exhibit suitable bandgaps and edge alignments for water splitting. • Exceptional stability and high electron mobility characterize these materials. • In-built electric fields effectively suppress electron-hole recombination. • Strain is an effective strategy to improve their light absorption. [ABSTRACT FROM AUTHOR]

A molecular dynamics simulation is performed to investigate the icosahedron in Mg 70 Zn 30 metallic glass during solidification at the cooling rate of 1 × 10 13  K/s. It is found that the 1551, 1541 and 1431 bond-types are closely related to 13-atom icosahedron-like clusters. Two kinds of clusters are very similar to full icosahedron in geometry. The three clusters can transform into each other by changing one bond between a pair of outer atoms. One distorted icosahedron act as the intermediate between the two others. This work provides an insight into the glass formation in alloy from the cluster-level structural viewpoint and will shed light on developing more metallic glasses. [ABSTRACT FROM AUTHOR]

The mechanism by which temperature sensitivity (TS) of soil N 2 O emissions is increased by agricultural management with application of nitrogen fertilizer (AMN) is unclear. We hypothesized that a higher TS of N 2 O emission induced by AMN is the result of the faster growth of specific microorganisms in response to faster nitrogen (N) mineralization at higher temperatures. To test this hypothesis, we used reciprocal transplants to separate the contributions of abiotic and microbial components to the TS of N 2 O emissions in an arable soil receiving organic and inorganic fertilizers and its neighboring natural grassland soil treated with two levels of N. N 2 O sources were separated with acetylene, and the abundances of N 2 O-producing microbes were assessed by quantifying the copy numbers of the associated functional genes. Compared with natural soil, only changes in abiotic properties increased the Q 10 (the factor by which the rate increases with a 10 °C rise in temperature) by 105.7%, while changes in both abiotic and the microbiome increased the Q 10 by 225.2%. Higher TS of N 2 O emission in the arable soil induced by a microbiome shift was associated with faster N mineralization, increased proportion of nitrification-N 2 O emission, and faster growth of ammonia-oxidizing bacteria at higher temperatures. Addition of ammonium nitrate further enhanced the TS of N 2 O emissions, the proportion of nitrification-N 2 O emission, and the increased extent of the growth of ammonia-oxidizing bacteria in the soil with AMN compared to the natural grassland soil. Substrate-driven growth of ammonia-oxidizing bacteria with higher substrate preference contributes significantly to the higher TS of N 2 O emission caused by AMN. [ABSTRACT FROM AUTHOR]

Silicon (Si), as a beneficial element for a number of crops, can significantly improve the growth and yield of crops partly through silicon-enhanced resistance to biotic and/or abiotic stress. However, the mechanisms of Si-improved growth and fruit quality of horticultural crops, in particular, remain poorly understood. In the present study, two-year field experiments were conducted aimed at testing the effects of different sources of silicate fertilizers applied on table grape yield, fruit quality and fruit commercial characteristics during storage period. For this, two table grape cultivars were tested with treatments including: (I) no silicate fertilizer (control), (II) steel slag fertilizer and (III) water-cooling slag fertilizer. The application rate of silicate fertilizer was 600 kg SiO 2 ha −1 . Fruit yield, cluster weight, berry weight, berry size ( i.e. length and width) were significantly increased by application of silicon fertilizers ( P < 0.05) in both cultivars. Table grape fruit yield was 13.5% higher in the treatment with either water-cooling slag fertilizer or steel-slag fertilizer than in the control across the two years tested. Silicon fertilization significantly improved fruit total soluble solids, the ratio of total soluble solids to titratable acidity (TSS/TA) and fruit firmness. Applying silicate fertilizer significantly extended the fruit shelf-life by decreasing fruit respiratory intensity, decay incidence and weight loss ( P < 0.05). Water-cooling slag fertilizer did not show a significant difference from steel slag fertilizer in grape yield and fruit quality. Our findings suggest that silicate fertilizer could prolong fruit shelf-life and increase the yield and quality of grape in a calcareous grey desert soil. [ABSTRACT FROM AUTHOR]

Nitrification inhibitors (NIs) have been used extensively to reduce nitrogen losses and increase crop nitrogen nutrition. However, information is still scant regarding the influence of NIs on nitrogen transformation, nitrous oxide (N2O) emission and nitrogen utilization in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. Therefore, a field trial was conducted to evaluate the effect of nitrapyrin (2-chloro-6-(trichloromethyl)-pyridine) on soil mineral nitrogen (N) transformation, N2O emission and nitrogen use efficiency (NUE) in a drip-fertigated cotton-growing calcareous field. Three treatments were established: control (no N fertilizer), urea (225 kg N ha-1) and urea+nitrapyrin (225 kg N ha-1+2.25 kg nitrapyrin ha-1). Compared with urea alone, urea plus nitrapyrin decreased the average N2O emission fluxes by 6.6–21.8% in June, July and August significantly in a drip-fertigation cycle. Urea application increased the seasonal cumulative N2O emission by 2.4 kg N ha-1 compared with control, and nitrapyrin addition significantly mitigated the seasonal N2O emission by 14.3% compared with urea only. During the main growing season, the average soil ammonium nitrogen (NH4+-N) concentration was 28.0% greater and soil nitrate nitrogen (NO3--N) concentration was 13.8% less in the urea+nitrapyrin treatment than in the urea treatment. Soil NO3--N and water-filled pore space (WFPS) were more closely correlated than soil NH4+-N with soil N2O fluxes under drip-fertigated condition (P<0.001). Compared with urea alone, urea plus nitrapyrin reduced the seasonal N2O emission factor (EF) by 32.4% while increasing nitrogen use efficiency by 10.7%. The results demonstrated that nitrapyrin addition significantly inhibited soil nitrification and maintained more NH4+-N in soil, mitigated N2O losses and improved nitrogen use efficiency in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. [ABSTRACT FROM AUTHOR]

Belowground biodiversity is essential for soil functioning, but the effect of belowground biodiversity loss on food safety is unknown. We investigated the loss of soil microbial diversity on insecticides accumulation in Brassica. We manipulated soil biodiversity using the dilution-to-extinction approach in a Brassica-soil-insecticide system, monitored microbial communities via high-throughput sequencing, and identified potential functional microbes. Compared with unsterilized soil, the richness of functional bacteria was reduced by 14.1%, 36.2%, 51.6% and 73.2%, respectively, in the corresponding sterilized soil inoculated with 1-, 10 −2 -, 10 −4 - and 10 −6 -fold diluted soil suspension. The acetamiprid and imidacloprid concentrations increased significantly in Brassica tissues grown in sterilized soil inoculated with 10 −6 -fold diluted suspension. A bacterial group predominated in functional microbes of soils inoculated with 1-, 10 −2 - or 10 −4 -fold diluted suspension, but the relative abundance declined in soil inoculated with a 10 −6 -fold diluted suspension. Our findings revealed that undesirable impacts by the loss of soil biodiversity at an intermediate level on the accumulation of soil contaminant in plants could be alleviated by microbial functional redundancy through disproportionally complementary growth of specific functional microbial taxa, but severe loss of soil biodiversity would threaten food safety. [ABSTRACT FROM AUTHOR]

Slag-based silicate fertilizer has been widely used to improve soil silicon- availability and crop productivity. A consecutive early rice-late rice rotation experiment was conducted to test the impacts of steel slag on soil pH, silicon availability, rice growth and metals-immobilization in paddy soil. Our results show that application of slag at a rate above higher or equal to 1 600 mg plant-available SiO2 per kg soil increased soil pH, dry weight of rice straw and grain, plant-available Si concentration and Si concentration in rice shoots compared with the control treatment. No significant accumulation of total cadmium (Cd) and lead (Pb) was noted in soil; rather, the exchangeable fraction of Cd significantly decreased. The cadmium concentrations in rice grains decreased significantly compared with the control treatment. In conclusion, application of steel slag reduced soil acidity, increased plant–availability of silicon, promoted rice growth and inhibited Cd transport to rice grain in the soil-plant system. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the impacts of organic-supplementation of a chemical fertilizer for improving soil biological activity, particularly towards disease suppression, in a drip-irrigated cotton system. Over a two-year field-based trial, our study characterized effects of partial substitution of chemical fertilizer with two types and amounts of organic components on the size, activity, carbon utilization potential, and culturable groups of pathogenic and antagonistic microbiota. The total microbial community size increased with application of chemical fertilizer ( P < 0.05), and more so when chemical fertilizer was supplemented with organic amendments ( P < 0.05). Alteration of microbial biomass carbon to nitrogen ratio, and the ratio of culturable bacteria and fungi, indicated that increases in the microbial community were underpinned by changes in bacteria. Enzymatic activity was greater in soils receiving fertilizer with organic supplement ( P < 0.05). Multivariate analysis indicated that there was no influence of fertilizer treatments on carbon utilization profiles (CUPs; P > 0.05), but a strong year-effect was evident ( P < 0.05). The population size of Verticillium dahliae and Fusarium oxysporum decreased with organic amendments ( P < 0.05), whilst antagonistic Trichoderma spp. and Bacillus spp. were inversely correlated to the pathogen populations. Overall, the results of this exploratory study support partial substitution of inorganic fertilizer with organic manure or bio-organic fertilizer to promote suppression of cotton root diseases. Associated benefits on soil biological quality will further increase the sustainability of this agroecosystem. [ABSTRACT FROM AUTHOR]

Using a trial and error method to measure amorphous forming ability in the experiment is a complex and time-consuming process. Therefore, it is necessary to devise a method that can rapidly and accurately predict the amorphous forming ability. In this study, two models, artificial neural network and convolutional neural network, are proposed for the prediction of amorphous forming ability of various amorphous alloys. The prediction accuracy of the two models reached 0.77623 and 0.71693, respectively, both of which were more than 19% higher than the reported prediction accuracy of the 13 criteria. This result shows that artificial neural network and convolutional neural network models can accurately predict the amorphous forming ability of a variety of amorphous alloys and provide theoretical guidance for the development and preparation of amorphous alloys. [ABSTRACT FROM AUTHOR]

The foliar uptake and transport of formaldehyde into Bracket plants from air via leaves and roots to external water was investigated in an air–plant–water system. The results indicated that formaldehyde could be quickly taken up by plant tissues, and that formaldehyde accumulated in leaves could be released rapidly back into air when the formaldehyde level in air was diminished. This rapid reversible translocation of formaldehyde between plant leaves and air resulted in high formaldehyde concentrations in leaf dews, depending upon exposure levels of formaldehyde in air. Meanwhile, formaldehyde could be transported from air to plant rhizosphere solution through downward transport. The concentration of formaldehyde in rhizosphere solutions increased with exposure time and the formaldehyde level in air. The efficiency of the leaf extracts to break down formaldehyde increased, probably because of an increase in oxidative potential of the leaf extracts. Taken together, the main mechanism of formaldehyde loss in air can be attributed to the accumulation by (or breakdown in) plant tissues; the removal rate of formaldehyde from air reached 135 μg h −1 plant −1 in the experimental condition. [ABSTRACT FROM AUTHOR]

Due to the frequent occurrence of extreme weather and severe environmental pollution, food security and human survival are at risk. Silicon, a key element in plant nutrition and environmental remediation, has a variety of applications in combatting various forms of abiotic and biotic stress and fostering healthy plants and soils. To establish a silicon-based defense barrier for plants, we firstly summarized and grouped the mechanisms of silicon functioning in plants: 1) molecular regulation and overall strengthening, 2) physical barrier and apoplastic obstruction, and 3) energy conservation. Additionally, the types and applications of silicon-based materials as soil remediation materials and fertilizers were discussed. Then, the challenges to build up such a barrier were analyzed in terms of silicon absorption and transportation, deposition and aggregation, and perception and regulation. An "external + internal" strategy was proposed to accelerate the establishment of a silicon-based barrier to enhance plants' resistance to extreme weather and environmental pollution, including high temperatures, drought, ultraviolet radiation, salt, heavy metals, nutrient deficiencies, new pollutants, and biotic stress. Finally, this paper emphasized the contribution of silicon barrier to healthy Soil-Plant-Atmosphere system that eventually benefit human health. This paper highlights the current understanding and future perspectives of silicon-related research in Soil-Plant-Atmosphere system, providing a reference for the application of silicon-based materials in environmental and agricultural fields. [ABSTRACT FROM AUTHOR]

Recently, the newly synthesized septuple-atomic layer two-dimensional (2D) material MoSi2N4 (MSN) has attracted attention worldwide. Our work delves into the effect of vacancies and external electric fields on the electronic properties of the MSN/graphene (Gr) heterostructure using first-principles calculation. We find that four types of defective structures, N-in, N-out, Si and Mo vacancy defects of monolayer MSN and MSN/Gr heterostructure are stable in air. Moreover, vacancy defects can effectively modulate the charge transfer at the interface of the MSN/Gr heterostructure as well as the work function of the pristine monolayer MSN and MSN/Gr heterostructure. Finally, the application of an external electric field enables the dynamic switching between n-type and p-type Schottky contacts. Our work may offer the possibility of exceeding the capabilities of conventional Schottky diodes based on MSN/Gr heterostructures. [ABSTRACT FROM AUTHOR]

GaN is a promising third-generation semiconductor material for fabricating nanodevices with nanoscale dimensions. In particular, thick-film sensors fabricated with GaN nanoparticles (NPs) have good gas-sensing characteristics. This study used molecular dynamics simulation to investigate the effect of temperature and size on the structural morphology and surface recrystallization of GaN NPs during sintering. The diffusion behavior and changes in the structural morphology of atoms were analyzed based on the shrinkage ratio, mean square displacement, potential energy, and other methods. The results show that during sintering, the surface of two GaN NPs experienced recrystallization, which expanded with increasing temperature; however, the obvious sintering phenomenon occurred at 3000 K. Interestingly, the surface recrystallization of NPs exhibited a lamellar structure formed through a specific stacking method of the crystal structure. However, when the size of one of the two NPs was reduced, the small NP rapidly melted and was induced to crystallize into a complete NP (having the same crystal orientation as the large NP) by the large NP. Moreover, NPs underwent rigid-body rotation and relative rotation during sintering; however, plastic deformation and dislocations resulting from rotation were only found in the neck of NPs of the same size. The study results provide valuable insights at the atomic scale regarding the sintering of GaN NPs and a useful reference for preparing and processing nanodevices. [ABSTRACT FROM AUTHOR]

Salicylic acid (SA) is a phenolic phytohormone that plays a vital role in plant development and mediates plant responses to plenty of adversity including arsenic (As) stress. The effects of exogenous addition of SA on As tolerance and As accumulation were assessed in two cultivars of rice (Oryza sativa L.) Nipponbare and Zhongzao 39, hydroponically grown with Kimura B nutrient solution under arsenite [As (III)] and dimethylarsonic acid (DMA) exposure. In the second ex-periment, the influence of soaking seed with SA on As uptake and As damages was investigated in rice (cv. Nipponbare) exposed to As (III) and DMA. The results showed that exogenous addition of SA significantly decreased the concentrations of hydrogen peroxide (H2O2) and malondialdehyde (MDA) in both As (III)- and DMA-stressed rice, indicating that SA alleviates As-induced oxidative damages in rice. SA increased the activity of antioxidant enzymes and, moreover, increased the relative amount of glutathione (GSH) and ascorbate (ASA) by accelerating the GSH-ASA circle system. Exogenous addition of SA significantly decreased the As concentration in both roots and shoots of rice under As(III) stress by influencing the expression of genes encoding As transporters, viz. OsLsi1, OsLsi2. The addition of SA significantly decreased the As content in shoots under DMA stress, which may be related to the expression of OsPTR7 involved in shoot xylem unloading. This finding may foster a novel perspective for reducing As accumulation in rice grains. [ABSTRACT FROM AUTHOR]

The efficacy of nitrification inhibitors (NIs) dicyandiamide (DCD) and 3,4-dimethylpyrazole phosphate (DMPP) varies with soil types. Understanding the microbial mechanisms for this variation may lead to better modelling of NI efficacy and therefore on-farm adoption. This study addressed the response patterns of mineral nitrogen, nitrous oxide (N2O) emission, abundances of N-cycling functional guilds and soil microbiota characteristics, in relation to urea application with or without DCD or DMPP in two arable soils (an alkaline and an acid soil). The inhibition of nitrification rate and N2O emission by NI application occurred by suppressing ammonia-oxidizing bacteria (AOB) abundances and increasing the abundances of nosZI-N2O reducers; however, abundances of ammonia-oxidizing archaea (AOA) were also stimulated with NIs-added in these two arable soils. DMPP generally had stronger inhibition efficiency than DCD, and both NIs' addition decreased Nitrobacter, while increased Nitrospira abundance only in alkaline soil. N2O emissions were positively correlated with AOB and negatively correlated with nosZI in both soils and AOA only in acid soil. Moreover, N2O emissions were also positively correlated with nirK-type denitrifiers in alkaline soil, and clade A comammox in acid soil. Amendment with DCD or DMPP altered soil microbiota community structure, but had minor effect on community composition. These results highlight a crucial role of the niche differentiation among canonical ammonia oxidizers (AOA/AOB), Nitrobacter and Nitrospira, as well as nosZI- and nosZII-N2O reducers in determining the varying efficacies of DCD and DMPP in different arable soils. [ABSTRACT FROM AUTHOR]

The effects of consecutive application of chemical fertilizer with or without organic fertilizer on soil N 2 O emissions and denitrifying community structure in a drip-irrigated field were determined. The four fertilizer treatments were (i) unfertilized, (ii) chemical fertilizer, (iii) 60% chemical fertilizer plus cattle manure, and (iv) 60% chemical fertilizer plus biofertilizer. The treatments with organic amendments (i.e. cattle manure and biofertilizer) reduced cumulative N 2 O emissions by 4.9–9.9%, reduced the N 2 O emission factor by 1.3–42%, and increased denitrifying enzyme activities by 14.3–56.2%. The nirK gene copy numbers were greatest in soil which received only chemical fertilizer. In contrast, nirS - and nosZ -copy numbers were greatest in soil amended with chemical fertilizer plus biofertilizer. Chemical fertilizer application with or without organic fertilizer significantly changed the community structure of nirK -type denitrifiers relative to the unfertilized soil. In comparison, the nirS - and nosZ -type denitrifier genotypes varied in treatments receiving organic fertilizer but not chemical fertilizer alone. The changes in the denitrifier communities were closely associated with soil organic carbon (SOC), NO 3 − , NH 4 + , water holding capacity, and soil pH. Modeling indicated that N 2 O emissions in this soil were primarily associated with the abundance of nirS type denitrifying bacteria, SOC, and NO 3 − . Overall, our findings indicate that (i) the organic fertilizers increased denitrifying enzyme activity, increased denitrifying-bacteria gene copy numbers, but reduced N 2 O emissions, and (ii) nirS - and nosZ -type denitrifiers were more sensitive than nirK -type denitrifiers to the organic fertilizers. [ABSTRACT FROM AUTHOR]

Ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) co-exist in soils. However, little is known about the effects of fertilization on the AOA and AOB communities and their relative contribution to soil nitrification. The objective of this field study was to determine the effects of four years of mineral and organic fertilizer (i.e., either cattle manure or biofertilizer) application on AOB and AOA in calcareous soil. The combined application of mineral and organic fertilizer (especially cattle manure) significantly increased the species richness (Chao1 and Ace) and α- diversity (Shannon index) of AOB ( P < 0.05) but not AOA ( P = 0.102). The AOA/AOB ratios were 1.64 and 1.19 in the unfertilized and the mineral fertilizer treatments, respectively. In contrast, the AOA/AOB rations were <1.0 in treatments with both mineral and organic fertilizer. These findings indicated that organic fertilizer increased AOB comparatively to AOA. Fertilizer addition was associated with significant shifts in the community structure of AOB ( P < 0.01) but had little effect on AOA. Soil potential nitrification rate were greatly increased by the application of either mineral fertilizer or mineral plus organic fertilizer ( P < 0.05). Moreover, potential nitrification rate were positively correlated with AOB abundance ( P < 0.001) but not AOA abundance ( P = 0.223). Variations in AOB community structure were closely associated with fertilizer-induced changes in soil pH, NH 4 + and SOC, whereas AOA community structure was only significantly correlated with SOC ( P = 0.040). Our findings suggest (i) that AOB is more sensitive than AOA to different fertilization regimes and (ii) that AOB contribute more than AOA to nitrification in this fertilized calcareous field soil. [ABSTRACT FROM AUTHOR]

The Hall–Petch relationship and deformation process in Ti3Al nano-polycrystalline alloys are investigated using molecular dynamics simulations in this research. The impact of different grain sizes and temperatures on mechanical characteristics was considered. Different Hall–Petch relations were detected for samples with the grain sizes ranging from 2 to 20 nm, inverse Hall–Petch relations in big grain sizes ranges, and positive Hall–Petch relations in the medium grain size region, respectively. A transition zone formed at the interception of positive and inverse Hall–Petch relations, which will vanish as the temperature rises. The critical grain size of the positive Hall–Petch relation decreases as the temperature rises from 10 to 600 K. With the grain size increases in the smaller grain size range, the yield stress increases, which is made by the grain boundary motion and rotation. Besides, temperatures affect mechanical characteristics. The rising temperatures lead to the decreasing dislocation density and a high grain boundary fraction. [ABSTRACT FROM AUTHOR]

In the realm of semiconductor materials, the integration of graphene (Gr) and gallium nitride (GaN) has emerged as a promising avenue for enhancing device performance. In this study, a Gr/GaN layered nanocomposite was constructed using molecular dynamics simulation and the LAMMPS code. Diamond abrasive was pressed into the composite at a speed of 50 m/s at 300 K, followed by ultrasonic vibration-assisted polishing on the (0001) plane along the [ 0 1 ‾ 10 ] direction. By rigorously exploring various factors such as number of Gr layers, vibration amplitudes, vibration frequencies and grinding speeds, the study elucidates the intricate mechanisms governing material removal and subsurface damage. Key findings reveal optimal processing conditions, including three layers of Gr, an amplitude of 5 Å, a vibration frequency of 80 GHz and a grinding speed of 100 m/s, which result in enhanced material removal rates and improved surface quality. Additionally, the insertion of Gr layers within the GaN matrix demonstrates a remarkable reduction in friction and wear rates, highlighting the potential for enhancing device reliability and performance. This comprehensive investigation not only advances our understanding of ultrasonic vibration-assisted grinding processes but also underscores the transformative impact of Gr/GaN composites in semiconductor device fabrication. [Display omitted] • Graphene-containing composites exhibit enhanced wear resistance and reduced wear rate. • Temperature and friction variations in UVAP resemble sinusoidal patterns. • The graphene layer presence results in nearly uniform thickness of the subsurface damage layer. • Higher amplitudes result in increased material removal, albeit with higher severity of subsurface damage layers. • Elevated velocities raise regional temperature, affecting atom removal quantity and subsurface quality. [ABSTRACT FROM AUTHOR]

The discovery of comammox Nitrospira has altered our perception of the nitrogen biogeochemical cycle. However, their functional importance compared to canonical ammonia oxidisers (i.e., ammonia-oxidising bacteria (AOB) and archaea (AOA)) in agricultural soils remains elusive, especially in acidic soils. Here, we assessed the functional importance of these functional guilds in nitrification and nitrous oxide (N 2 O) emissions in three acidic agricultural soils by using a range of nitrification inhibitors (acetylene, 3,4-dimethylpyrazole phosphate (DMPP) and different concentrations of 1-octyne) and monitored their community assemblage and population dynamics. The sensitivity of comammox Nitrospira clade A to 1-octyne varied across soils, highlighting that the inappropriate use of 1-octyne can lead to misestimation of comammox activity. AOA were key NH 3 oxidisers in the three soils, while AOB also contributed significantly to nitrification in one soil. In contrast, comammox Nitrospira always played a minor role in ammonia oxidation and N 2 O emissions, likely due to their low abundances, restricted cellular kinetic properties and N 2 O production mechanisms. Together, this study demonstrates that comammox Nitrospira play a less important role in ammonia oxidation and N 2 O production in acidic agricultural soils than AOA and AOB, thereby providing important novel insights into the mitigation of nitrogen fertiliser loss and N 2 O emissions. • Comammox play a minor role in NH 3 oxidation and N 2 O emissions in acidic arable soils. • AOB are functionally active in acidic agricultural soils. • The sensitivity of comammox Nitrospira clade A to 1-octyne varies across soils. [ABSTRACT FROM AUTHOR]

• The topologically close–packed (TCP) atoms dominate in undercooled Zr liquid. • The TCP atoms are energetic and structural favourable and then stabilize super-cooled liquid. • Three stages between TCP and BCC competition process can be observed. • Crystallization cannot occur until the TCP atoms with T 5 > 1/3 drops in number and interconnect. The crystallization of undercooled liquid zirconium (Zr) during isothermal relaxation was investigated by molecular dynamics simulation. In particular, the dynamic competition mechanism between the topologically close–packed (TCP) and body–centered cubic (BCC) structures during crystallization was deeply studied using the atomic energy, the pair distribution function and the largest standard cluster analysis (LaSCA). The study found that TCP clusters, rather than icosahedral clusters, play an important role in hindering the crystallization of the undercooled liquid. The TCP clusters with T 5 = n 5 /(n 4 + n 5 + n 6) > 1/3 (where n 4 , n 5 and n 6 represent the number of common neighbor sub-cluster: 444, 555 and 666 respectively) stabilize the undercooled liquid and prevent crystallization; while the other TCPs exhibits an evolution trend similar to that of BCC-like clusters. Furthermore, three stages of the competition process between TCP and BCC structures can be observed, and crystallization does not happen until the number of major TCP clusters with T 5 > 1/3 decreases and the average degree of interconnection among them weakens. [ABSTRACT FROM AUTHOR]

• With a crystallization-like E-T curve Ni 50 Ag 50 amorphization includes a LLT and a LST. • The average cutoff distance exported by LaSCA is useful in identifying state transitions. • LLT can be identified by the evolution of SRO and MRO structures, where MRO shows the glass feature. • In LST, TCP-based MRO and TLRO structures grow rapidly. • TCP structures reflect the essential nature of amorphous systems more effectively than ICOs. A molecular dynamics simulation of rapid cooling at a cooling rate of 1011 K/s for Ni 50 Ag 50 alloys was conducted. The rapid cooling process was analyzed by using the system energy, the pair distribution function, and the largest standard cluster analysis. It is found that with a crystallization-like energy curve the solidification of Ni 50 Ag 50 alloy experiences a liquid-liquid and a liquid-solid transition (LLT and LST), finally result in an amorphous solid. In LLT stage the topologically close-packed (TCP) short-range order structures of both crystal (S666) and glass (S555) increase; whereas only glass medium-range order structures are formed. TCP-based long-range order (LRO) structures of glass do not increase until the beginning of the LST. Even in solid (T < T g) the LRO parameter based on ICO structures fluctuates violently, while that based on TCP structures is quite stable. Therefore, TCP not only is the basic structural characteristics of disordered system but also reasonably represents the metastability of metallic glasses. These findings not only clarify the importance of LLT for the glass forming ability of alloys, but also fully demonstrate the effectiveness and necessity of TCP structures for describing the structure of amorphous systems. [ABSTRACT FROM AUTHOR]

Two-phase Îł -TiAl/ α 2-Ti3Al lamellar intermetallics have attracted considerable attention because of their excellent strength and plasticity. However, the exact deformation mechanisms remain to be investigated. In this paper, a solidified lamellar Tiâ€"Al alloy with lamellar orientation at 0°, 17°, and 73° with respect to the loading direction was stretched by utilizing molecular dynamics (MD) simulations. The results show that the mechanical properties of the sample are considerably influenced by solidified defects and tensile directions. The structure deformation and fracture were primarily attributed to an intrinsic stacking fault (ISF) accompanied by the nucleated Shockley dislocation, and the adjacent extrinsic stacking fault (ESF) and ISF formed by solidification tend to form large HCP structures during the tensile process loading at 73°. Moreover, cleavage cracking easily occurs on the Îł / α 2 interface under tensile deformation. The fracture loading mechanism at 17° is grain boundary slide whereas, at 73° and 0°, the dislocation piles up to form a dislocation junction. [ABSTRACT FROM AUTHOR]

Silicon (Si) can alleviate aluminum (Al) toxicity in rice (Oryza sativa L.), but the mechanisms underlying this beneficial effect have not been elucidated, especially under long-term Al stress. Here, the effects of Al and Si on the suberization and development of rice roots were investigated. The results show that, as the Al exposure time increased, the roots accumulated more Al, and Al enhanced the deposition of suberin in roots, both of which ultimately inhibited root growth and nutrient absorption. However, Si restricted the apoplastic and symplastic pathways of Al in roots by inhibiting the uptake and transport of Al, thereby reducing the accumulation of Al in roots. Meanwhile, the Si-induced drop in Al concentration reduced the suberization of roots caused by Al through down-regulating the expression of genes related to suberin synthesis and then promoted the development of roots (such as longer and more adventitious roots and lateral roots). Moreover, Si also increased nutrient uptake by Al-stressed roots and thence promoted the growth of rice. Overall, these results indicate that Si reduced Al-induced suberization of roots by inhibiting the uptake and transport of Al in roots, thereby amending root growth and ultimately alleviating Al stress in rice. Our study further clarified the toxicity mechanism of Al in rice and the role of Si in reducing Al content and restoring root development under Al stress. [ABSTRACT FROM AUTHOR]

Soil contamination by heavy metals has become a serious threat to global food security. The application of silicon (Si)-based materials is a simple and economical method for producing safe crops in contaminated soil. However, the impact of silicon on the heavy-metal concentration in plant roots, which are the first line in the chain of heavy-metal entering plants and causing stress and the main site of heavy-metal deposition in plants, remains puzzling. We proposed a process-based model (adsorption-diffusion model) to explain the results of a collection of 28 experiments on alleviating toxic metal stress in plants by Si. Then we evaluated the applicability of the model in Si-mitigated trivalent chromium (Cr[III]) stress in rice, taking into account variations in experimental conditions such as Cr(III) concentration, stress duration, and Si concentration. It was found that the adsorption-diffusion model fitted the experimental data well (R2 > 0.9). We also verified the binding interaction between Si and Cr in the cell wall using SEM-EDS and XPS. In addition, we designed a simplified biomimetic device that simulated the Si in cell wall to analyze the dual-action switch of Si from increasing Cr(III) adsorption to blocking Cr(III) diffusion. We found that the adsorption of Cr(III) by Si decreased from 58% to 7% as the total amount of Cr(III) increased, and finally the diffusion blocking effect of Si dominated. This study deepens our understanding of the role of Si in mitigating toxic metal stress in plants and is instructive for the research and use of Si-based materials to improve food security. [Display omitted] • Si reduces toxic metal concentration in shoots but sometimes increases it in roots. • The adsorption-diffusion model was developed to explain the effect of Si in roots. • Si exhibited dual roles in roots by increasing adsorption and blocking diffusion. • The intensity and duration of stress and Si concentration affected Si's function. [ABSTRACT FROM AUTHOR]

Silicon (Si) has been well-known to enhance plant resistance to heavy-metal stress. However, the mechanisms by which silicon mitigates heavy-metal stress in plants are not clear. In particular, information regarding the role of Si in mediating resistance to heavy-metal stress at a single cell level is still lacking. Here, we developed a hierarchical system comprising the plant, protoplast, and suspension cell subsystems to investigate the mechanisms by which silicon helps to alleviate the toxic effects of trivalent chromium [Cr(III)] in rice. Our results showed that in whole-plant subsystem silicon reduced shoot Cr(III) concentration, effectively alleviating Cr(III) stress in seedlings and causing changes in antioxidant enzyme activities similar to those observed at lower Cr(III) concentrations without silicon added. However, in protoplast subsystem lacking the cell wall, no silicon deposition occurred, leading to insignificant changes in cell survival or antioxidation processes under Cr(III) stress. Conversely, in suspension cell subsystem, silicon supplementation substantially improved cell survival and changes in antioxidant enzyme activities under Cr(III) stress. This is due to the fact that >95% of silicon was on the cell wall, reducing Cr(III) concentration in cells by 7.7%–10.4%. Collectively, the results suggested that the silicon deposited on the cell wall hindered Cr(III) bio-uptake, which consequently delayed Cr(III)-induced changes in antioxidant enzyme activities. This research emphasizes the significance of cell walls in Si-alleviated heavy-metal stress and deepens our understanding of silicon functioning in plants. Furthermore, the hierarchical system has great potential for application in studying the functioning of other elements in plant cell walls. [Display omitted] • A hierarchical system was developed to explore the Si functioning mechanism. • The system includes three subsystems: plant, protoplast, and suspended cell. • Si affects rice seedlings' antioxidant enzyme activity by reducing Cr(III) uptake. • Silicon presents different roles on protoplasts and suspension cells. • 95% of Si is on cell walls of suspension cells and acts as a defense barrier. [ABSTRACT FROM AUTHOR]

Phosphorus (P) accumulation in croplands resulting from ever-increasing input of P fertilizer strongly influences soil microbial growth and activities, which is expected to alter the soil priming effect (PE) induced by plant residue. However, the effect of P availability on the magnitude and direction of PE remains largely unexplored and the underlying microbial mechanisms are still unclear. Therefore, a 40-day incubation experiment was established by adding C4-maize straw to C3-soils with or without long-term P fertilizer inputs to investigate PE and accompanied dynamics of microbiota. The results revealed that in both soils, straw application caused positive real PEs via a "microbial co-metabolism" mechanism, accompanied by a microbial succession from the dominance of r- and K-strategists to K-strategists (mainly fungi). In addition, long-term amendment with P increased PE by 83.2% compared with no P fertilization control, which was mainly mediated by K-strategists, especially the fungal families Chaetomiaceae and Myrmecridiaceae. The increased PE was accompanied by enhanced microbial biomass carbon, extracellular enzyme activities, and bacterial gene abundance, confirming the "stoichiometric decomposition" theory. Meanwhile, deviating from the conventional paradigm, higher phosphatase activity and lower enzymatic stoichiometry of carbon (C)-to-P ratios in high-P soil compared with that in low-P soil suggested stronger "P mining" with high-P availability. [ABSTRACT FROM AUTHOR]

High‐quality TiAl alloy is used to fabricate aerospace equipment with excellent mechanical properties because of its interesting properties, including low density, high specific yield strength, and better corrosion resistance. However, the fabrication of high‐quality TiAl alloy is challenging because the connection mechanism between different types of clusters in TiAl alloy during the rapid cooling process is not clear. This study uses molecular dynamics (MD) simulation methods to study the connection models of icosahedral (ICO) structures and other defective ICO structures at different cooling rates. The ICO structures represent the short‐range ordered structure in the system. Moreover, the complex connections between the ICO and its defective structures constitute the basic structural features of TiAl metallic glass. The results show that the connections between ICO and its defective structures differ significantly with the cooling rate. It is easier to form a more complex nanostructure connected by the ICO structures with higher proportion of Al central atoms at the lower cooling rate. As the temperature drops at the same rate, the number of Al central atoms with smaller atomic radius in the icosahedrons increases gradually, giving them an absolute advantage. [ABSTRACT FROM AUTHOR]

Research on the structural properties of silicon crystal nucleation during solidification has been the subject of numerous classic studies in condensed matter physics and material science. The approach to structural properties of Si crystal nucleation adopted for this paper is based on molecular dynamics simulation at the cooling rate of 1010 K/s. Using the entropy of largest standard cluster and the pair distribution function, it is able to obtain microstructural evolution characteristics. The pleomorphism properties and distribution of Si crystal nucleation was presented by the visualization method. The systematic evolution diagram illustrates the competitive growth between cubic diamond and hexagonal diamond structures which shows that the crystal nucleus easily forms and then grow during a short period of time at the initial crystallization stage. The orientation characteristics after crystal nucleation in space are systematically analyzed and it is found that the nucleation and orientation of crystals are weakly dependent, that is, the orientations of crystals are homogeneous and random. In addition, the visualization results show that various twins exist in the system, including coherent twins, rotating twins and some torsional twins, which improve the structural stability to a certain degree. This study further explores crystal nucleation on the atomic scale and it is hoped that this research will contribute to expanding the understanding of the orientation distribution and crystallization behavior of amorphous silicon during the growth process. [ABSTRACT FROM AUTHOR]

A 28-day microcosm experiment was conducted using three paddy soils (an alluvial paddy soil, a loess-formed paddy soil, and a yellow clayey paddy soil) to investigate the impact of procyanidin on N2O emissions and associated microbial mechanisms. The efficacy of procyanidin on N2O emissions varied among the paddy soils tested, with an average inhibition rate ranging from 2.7% in the alluvial paddy soil to 57.1% in the loess-formed paddy soil. Furthermore, suppression of N2O emissions by procyanidin occurred alongside fluctuations in nitrate reductase activity and nirS- and nirK-type denitrifiers abundance. The correlation analysis indicates that nitrate reductase, clade I nirS-denitrifiers, clade I or II, and clade III nirK-denitrifiers were closely linked to N2O emissions. These findings provide evidence that procyanidin is capable of limiting N2O emissions in paddy soils by inhibiting nitrate reductase and different clades of nirS-/nirK-denitrifiers. [ABSTRACT FROM AUTHOR]

A microcosm study was established using three arable soils differing in both physicochemical properties and AOB or AOA dominance of ammonia oxidization. Nitrification and N2O emissions were quantified under 10 Pa C2H2, 1-octyne, or 3,4-dimethylpyrazole phosphate (DMPP), and the community composition and abundance of AOA and AOB were assessed. Amendment of soil with DMPP had a comparable effect to 1-octyne on AOB activities, composition, and N2O emissions across soils. By blocking AOB activity, both DMPP and 1-octyne supported higher rates of AOA growth in both the acid and alkaline soils. Approximately, 50% of ammonia-oxidizing activity in the acid soil was attributed to AOB activity by phylotypes affiliated with Nitrosomonas communis. When AOB were blocked by DMPP or 1-octyne across all soils, recovery of AOA communities was associated with the increased abundance of Nitrososphaera viennesis. [ABSTRACT FROM AUTHOR]

Background and aims: Silicon (Si) is known to alleviate aluminum (Al) toxicity in a number of plant species; however, the mechanisms of Si-triggered Al detoxification have not been elucidated, especially in rice (Oryza sativa). We investigated the interactions between Si and Al in root and the role of cell wall polysaccharides in rice resistance to Al. Methods: Rice seedlings were grown in 0.5 mM CaCl2 solution with or without 50 µM Al and 1.0 mM H4SiO4 for 24 h. The cell expansion and oxidative injury of root were measured by histochemical analyses; Al accumulation and distribution in root apices were determined by inductively coupled plasma mass spectrometry (ICP-MS); the degree of pectin methylesterification was analyzed by immunofluorescence, and the expression of genes (e.g. OsPME) related to Al resistance was measured by quantitative real-time PCR. Results: Si relieved the inhibition of cell elongation and oxidative injury caused by Al and significantly reduced Al content (by about 41 %) in cell wall (CW). Meanwhile, Si inhibited pectin methylesterase (PME) activity and its gene expression, thereby increasing the degree of pectin methylesterification, and reduced the content of hemicellulose, which was the main binding site for Al in CW, under Al stress. Furthermore, Si decreased the non-exchangeable Al fraction of CW in root, but did not change the cation exchange capacity of CW. Conclusions: Si reduces the deposition of Al in the cell wall of rice root apex by decreasing both the degree of pectin demethylesterification and the content of hemicellulose, thereby alleviating Al stress. [ABSTRACT FROM AUTHOR]

[Display omitted] • Graphene enables copper nanodroplets to form hexagonal close-packed layers. • The TCP atoms in copper nanodroplets hinders the formation of crystal atoms. • Graphene improves the temperature and life-time of the liquid–solid transition. • Graphene affects the nucleation work and crystallization pathway of nanodroplets. • Wettability can tune the temperature and lifetime of solid–liquid coexistence. The microstructure determines the macro properties, so the chemical and physical properties of nanoparticles can be tuned by changing their structures. A molecular dynamics simulation for the rapid solidification of Cu nanodroplets on the graphene sheet is conducted to investigate the effect of substrate on nanoparticles. The phase transition, structure evolution, and crystallinity are quantified by the potential energy, the largest standard cluster analysis, and Bond-orientation order parameters. It is found that the solidification is inhomogeneous and stepwise crystallization. Interestingly, originating from the graphene wettability, different solid–liquid coexistence states are obtained that may have the potential to modify the chemical and physical reactions on nanoparticles. The temperature of this solid–liquid coexistence state depends strongly on the structural evolution of crystallization and thus can be regulated by the wetting properties of the graphene substrate. These results significantly extend the fundamental understanding of heterogeneous nucleation in nanodroplets, providing important insights for designing and fabricating composite materials with multifunctional properties. [ABSTRACT FROM AUTHOR]

Silicon (Si) can alleviate salt stress by decreasing Na+ bypass flow in rice (Oryza sativa L.), however, the mechanisms underpinning remain veiled. In this study, we investigated the roles of OsLsi1 and OsLsi2 in Si-induced reduction of bypass flow and its resultant alleviation of salt stress by using lsi1 and lsi2 mutants (defective in OsLsi1 and OsLsi2, respectively) and their wild types (WTs). Under salt stress, Si promoted plant growth and decreased root-to-shoot Na+ translocation in WTs, but not in mutants. Simultaneously, quantitative estimation and fluorescent visualization of trisodium-8-hydroxy-1,3,6-pyrenetrisulphonic (PTS, an apoplastic tracer) showed Si reduced bypass flow in WTs, but not in mutants. Energy-dispersive X-ray microanalysis (EDX) showed Si was deposited at root endodermis in WTs, but not in mutants. Moreover, results obtained from root split experiment using lsi1 WT showed down-regulated expression of Si transport genes (OsLsi1 and OsLsi2) in root accelerated Si deposition at root endodermis. In summary, our results reveal that Si deposition at root endodermis and its resultant reduction of Na+ bypass flow is modulated by OsLsi1 and OsLsi2 and regulated by the expression of OsLsi1 and OsLsi2 , implying that root Si deposition could be an active and physiologically-regulated process in rice. • Si deposition at root endodermis reduces Na+ bypass flow and alleviates salt stress. • Root Si deposition is modulated by OsLsi1 and OsLsi2. • Down-regulated OsLsi1 and OsLsi2 accelerated endodermis Si deposition. • Si deposition in root could be an active and physiologically-regulated process. [ABSTRACT FROM AUTHOR]

Aims: As a vital polysaccharide related to mechanisms of plant resistance to trace metal in the root cell wall, the role of hemicellulose in cadmium (Cd) accumulation in hyperaccumulators is still unknown. We investigated hemicellulose modification in response to Cd in two populations of Sedum alfredii. Methods: Nonhyperaccumulating population (NHP) and hyperaccumulating population (HP) of S. alfredii were grown in nutrient solutions with or without 25 μM Cd for 15 d. Monosaccharide composition of root cell wall hemicellulose and its remolding mechanisms (e.g. enzyme activity and gene expression) were analyzed by using gas chromatography-mass spectrometer (GC-MS), fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance (NMR) and quantitative real-time PCR techniques. Results: In 25 μM Cd treatment, root cell wall hemicellulose in the NHP significantly (P < 0.05) increased and its hemicellulose-bound Cd was nearly 2.5-fold higher than that of HP. In the presence of Cd, xylose and glucose, proved to be the main component of hemicellulose, were higher in the NHP than in the HP owing to the up-regulation of XET/XEH and encoding gene (XTH 31). 113Cd-NMR and FTIR results indicated that hemicellulose with hydroxyl and carboxyl groups of HP retained less Cd than that of NHP. Conclusion: Hemicellulose modification decreased the Cd-binding capacity of the root cell wall and increased the entry of Cd in the shoot of HP S. alfredii. [ABSTRACT FROM AUTHOR]

The use of high-energy ions or clusters to bombard graphene is emerging as a new method for the theoretical study of graphene properties. In this study, using molecular dynamics simulations and empirical potentials, the behaviors of graphene after bombardment by C60 under different initial velocities from 13.7 to 15.7 km/s were investigated. The simulations showed four types of defects: Stone–Wales defects, single vacancy defects, multiple vacancy defects, and out-of-plane carbon adatoms. The self-healing phenomenon of defective graphene was observed. In the low-speed region (< 14.5 km/s), the self-healing ability of graphene is enhanced at higher temperature. However, the effect of temperature is not obvious in the high-speed region, where velocity dominates. To repair vacancy defects in graphene, a physical method was proposed. The initial positions of lost atoms were traced, and then, the atoms were slowly dropped into the vacancy defects to effect repair. The simulations provide a fundamental understanding of bombardment between graphene and C60 and propose a new method for repairing vacancy defects in graphene. [ABSTRACT FROM AUTHOR]

The study of two-dimensional flexible materials in mechanic and optics has gained significant attention. By applying strain to modify the internal structure of materials, researchers can investigate the resulting mechanical and optical changes, offering exciting opportunities for further exploration in this field. The electronic structure, mechanical properties, and optical properties of the two-dimensional trigonal system Bi 2 Te 2 Se under biaxial strain regulation were investigated by using the first-principles plane pseudopotential plane wave method based on density generalized function theory. The analysis reveals that the energy bandwidth of Bi 2 Te 2 Se decreases with increasing strain until the band gap reaches 0 at 9% strain, causing the system to shift from a semiconductor to a conductor. The electronic density of states is primarily determined by the 6 p orbitals of Bi and 5 p orbitals of Te. With regards to its mechanical properties, Bi 2 Te 2 Se satisfies the mechanical stability criterion under different strains. As the strain increases from 0% to 6%, the material becomes increasingly brittle, with its interior transitioning from metallic to covalent bonds. However, the material toughness begins to improve from 6% to 9%, with the interior transitioning from covalent to metallic bonding. The performance improvement of Bi 2 Te 2 Se varies depending on the two electric field polarization vectors along [1 0 0] and [0 0 1] directions under strain. The material shows distinct application prospects in terms of absorption coefficient, reflectivity, refractive index, and lossiness under two directions. This paper provides a theoretical reference for the future mechanical and optical applications of Bi 2 Te 2 Se. [ABSTRACT FROM AUTHOR]

Trivalent chromium [Cr(III)] is a threat to the environment and crop production. Silicon (Si) has been shown to be effective in mitigating Cr(III) toxicity in rice. However, the mechanisms by which Si reduces Cr(III) uptake in rice are unclear. Herein, we hypothesized that the ability of Si to obstruct Cr(III) diffusion via apoplastic bypass is related to silicic acid polymerization, which may be affected by Cr(III) in rice roots. To test this hypothesis, we employed hydroponics experiments on rice (Oryza sativa L.) and utilized apoplastic bypass tracer techniques, as well as model simulations, to investigate 1) the effect of Si on Cr(III) toxicity and its obstruction capacity via apoplastic bypass, 2) the effect of Cr(III) on silicic acid polymerization, and 3) the relationship between the degree of silicic acid polymerization and its Cr(III) obstruction capacity. We found that Si reversed the damage caused by Cr(III) stress in rice. Si exerted an obstruction effect in the apoplast, significantly decreasing the share of Cr(III) uptake via the apoplastic bypass from 18% to 11%. Moreover, Cr(III) reduced silica particles' radii and increased Si concentration in roots. Modeling revealed that a 5-fold reduction in their radii decreased the diffusion of Cr(III) in apoplast by approximately 17%. We revealed that Cr(III) promoted silicic acid polymerization, resulting in the formation of a higher number of Si particles with a smaller radius in roots, which in turn increased the ability of Si to obstruct Cr(III) diffusion. This negative feedback regulatory mechanism is novel and crucially important for maintaining homeostasis in rice, unveiling the unique role of Si under Cr(III) ion stress and providing a theoretical basis for promoting the use of Si fertilizer in the field. [Display omitted] • Si in rice mitigates Cr(III) stress by obstructing Cr(III) uptake via apoplastic bypass. • Cr(III) reduces Si particle radius and increases root Si concentration. • A great number of smaller Si particles can improve their obstructing effect. • Si in rice alleviates Cr(III) stress via a negative feedback regulatory mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • A data-driven machine learning approach is proposed for predicting metallic glass forming ability. • A three-step feature selection method was devised to effectively filter out the best feature set. • Oversampling and non-linear transformation techniques are used to improve the imbalance distribution of the data set. • A design solution for enhanced metallic glass forming ability is proposed based on the SHAP method. Scientists have extensively studied metallic glasses (MGs) for their excellent properties and potential applications. However, the limited glass forming ability (GFA) of MGs poses a significant challenge in engineering fabrication, severely limiting their scope of application. Herein, we collected data from 167 peer-reviewed research articles and 2 commonly used datasets and constructed a comprehensive dataset containing 2085 data points. We employed gradient boosting algorithmic models, such as XGBoost, LGBoost, and AdaBoost, for selecting the best feature set and constructing the most effective model from among 118 feature parameters through techniques such as three-step feature selection method, ten-fold cross-validation, and grid search. As the uneven distribution of the original dataset significantly impacts the model's performance, we implemented five nonlinear transformation techniques and three oversampling techniques to improve the model. The results indicated that the nonlinear and oversampling techniques improved the model's performance by improving the distribution balance. Finally, we interpreted the constructed models through Shapley additive explanation, providing relevant rules concerning GFA. The techniques employed and the rules presented herein contribute to the statistical understanding of GFA and may facilitate the discovery of novel MGs. [ABSTRACT FROM AUTHOR]

Salicylic acid (SA), as an enigmatic signalling molecule in plants, has been intensively studied to elucidate its role in defence against biotic and abiotic stresses. This review focuses on recent research on the role of the SA signalling pathway in regulating cadmium (Cd) tolerance in plants under various SA exposure methods, including pre-soaking, hydroponic exposure, and spraying. Pretreatment with appropriate levels of SA showed a mitigating effect on Cd damage, whereas an excessive dose of exogenous SA aggravated the toxic effects of Cd. SA signalling mechanisms are mainly associated with modification of reactive oxygen species (ROS) levels in plant tissues. Then, ROS, as second messengers, regulate a series of physiological and genetic adaptive responses, including remodelling cell wall construction, balancing the uptake of Cd and other ions, refining the antioxidant defence system, and regulating photosynthesis, glutathione synthesis and senescence. These findings together elucidate the expanding role of SA in phytotoxicology. [ABSTRACT FROM AUTHOR]

Anammox are unusual members of the microbial community contributing to N losses via anaerobic ammonium oxidation. Anammox use nitrite as a substrate and produce hydrazine as an intermediate product. Up to date, the effects of dissolved oxygen and moisture dynamics on anammox potential and microbial community in agricultural soils were poorly understood. In this study, we investigated the interaction of dissolved oxygen and moisture contents as factors affecting the soil anammox process. The experiment had four fertilization treatments i.e. Control (CK), Chemical fertilizer (CF), Pig composted manure plus chemical fertilizer (PMCF), and Straw returned to soil plus chemical fertilizer (SRCF) with different water contents, 70%-FC, Alternate wetting and drying (AWD), Flooding I (D.O 5.8 mg L−1), and Flooding II (D.O 2.6 mg L−1). 15N-isotopic tracer technique was used to evaluate the anammox and denitrification rates. The results showed that the anammox rate ranged from the lowest 0.56 nmol N 2 ·g−1·h−1 in CF (with 70% FC water) to the highest rate of 1.47 nmol N 2 ·g−1·h−1 in SRCF (with flooding II). In water treatments, the average lowest and highest anammox rates were in the 70% FC (0.61 nmol N 2 ·g−1·h−1) and Flooding II (1.14 nmol N 2 ·g−1·h−1), respectively. Moreover, under soil treatments, the minimum average anammox rate was found in the PMCF (0.76 nmol N 2 ·g−1·h−1) and maximum in the SRCF (1.01 nmol N 2 ·g−1·h−1). Interestingly, anammox genes copy numbers were highest in alternate wetting and drying conditions under all fertilizer treatments rather than in continuous flooding. The phylogenetic analysis showed that Ca. Brocadia was dominating while some of Ca. Jettenia was also present. In conclusion, alternate wetting and drying could increase the number of anammox bacteria and microbial diversity. Unlabelled Image • Alternate wetting and drying (AWD) can enhance Anammox rate and microbial diversity. • Consistently higher dissolved oxygen can inhibit the Anammox process/activity. • Long-term application of pig manure can decrease the Anammox activity. • Anammox activity has a positive relationship with hydrazine gene abundance. [ABSTRACT FROM AUTHOR]

Abstract Phytoextraction is an attractive strategy for remediation of soils contaminated by heavy metal (HM), yet the effects of this practice on biochemical processes involved in soil nutrient cycling remain unknown. Here we investigated the impact of successive phytoextraction with a Cd/Zn co-hyperaccumulator Sedum alfredii (Crassulaceae) on potential nitrification rates (PNRs), abundance and composition of nitrifying communities and functional genes associated with nitrification using archaeal and bacterial 16S rRNA gene profiling and quantitative real-time PCR. The PNRs in rhizosphere were significantly (P < 0.05) lower than in the unplanted soils, and decreased markedly with planting time. The decrease of PNR was more paralleled by changes in numbers of copy and transcript of archaeal amoA gene than the bacterial counterpart. Phylogenetic analysis revealed that phytoextraction induced shifts in community structure of soil group 1.1b lineage-dominated ammonia-oxidizing archaea (AOA), Nitrosospira cluster 3-like ammonia-oxidizing bacteria (AOB) and Nitrospira -like nitrite-oxidizing bacteria (NOB). A strong positive correlation was observed between amoA gene transcript numbers and PNRs, whereas root exudates showed negative effect on PNR. This effect was further corroborated by incubation test with the concentrated root exudates of S. alfredii. Partial least squares path model demonstrated that PNR was predominantly controlled by number of AOA amoA gene transcripts which were strongly influenced by root exudation and HM level in soil. Our result reveals that successive phytoextraction of agricultural soil contaminated by HMs using S. alfredii could inhibit ammonia oxidation and thereby reduce nitrogen loss. Graphical abstract Unlabelled Image Highlights • Successive phytoextraction by S. alfredii significantly reduced the PNR in rhizosphere. • Successive phytoextraction decreased the abundance and activity of archaeal amoA gene. • Successive planting with S. alfredii obviously altered the structure of nitrifying community. • Root exudates of S. alfredii inhibited ammonia oxidation by decreasing ammonia-oxidizing microbe activity. [ABSTRACT FROM AUTHOR]