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The basic wood density influences the carbon stock, playing a crucial role in climate-changing global mitigation through carbon sequestration. Understanding wood carbon release depends on the Nitrogen assessment and CN ratio. Therefore, our research aimed to: (i) Compare basic density, organic carbon, nitrogen, and C/N ratio among the Khaya grandifoliola, K. ivorensis, and K. senegalensis; (2) Analyze the gradient along positions and diameter of the commercial stem; (3) Recommend the most representative sampling position for each species based on the diameter. The experimental area is located in Southeastern Brazil. Twelve average-diameter trees per species were cut down, and wood disc samples were collected at 0, 25, 50, 75, and 100% commercial height. Our results show statistical differences in wood basic density among the species, and K. senegalensis has the highest basic density, 592 kg m3. There was no statistical difference in organic carbon between species and along the stem. Stem diameter instead of commercial height improved the variable studied, confirming the research hypothesis. Sampling at 17% of the commercial height, ranging to 18–22 cm stem diameters, is recommended for greater representativeness. [ABSTRACT FROM AUTHOR]

In northern hardwood forests, litter decomposition might be affected by nutrient availability, species composition, stand age, or access by decomposers. We investigated these factors at the Bartlett Experimental Forest in New Hampshire. Leaf litter of early and late successional species was collected from four stands that had full factorial nitrogen and phosphorus additions to the soil and were deployed in bags of two mesh sizes (63 µm and 2 mm) in two young and two mature stands. Litter bags were collected three times over the next 2 years, and mass loss was described as an exponential function of time represented by a thermal sum. Litter from young stands had higher initial N and P concentrations and decomposed more quickly than litter from mature stands (p = 0.005), regardless of where it was deployed. Litter decomposed more quickly in fine mesh bags that excluded mesofauna (p < 0.001), which might be explained by the greater rigidity of the large mesh material making poor contact with the soil. Neither nutrient addition (p = 0.94 for N, p = 0.26 for P) nor the age of the stand in which bags were deployed (p = 0.36) had a detectable effect on rates of litter decomposition. [ABSTRACT FROM AUTHOR]

Nitrogen and sulfur are essential macronutrients in plant growth and development, and their interaction profoundly influences gene expression, metabolic activities, and adaptability in plants, directly affecting plant growth and yield. Garlic (Allium sativum L.) is a crop of significant economic and medicinal value. However, despite the critical role of the nitrogen–sulfur interaction in garlic's adaptability, yield, and quality, the specific mechanisms underlying these effects remain unclear. In this study, transcriptomic and metabolomic analyses were employed to investigate the effects of combined sulfur and nitrogen application on garlic bulb tissues. The results show that the combined application of sulfur and nitrogen significantly increased the diameter and weight of garlic bulbs by 14.96% and 35.47%, respectively. The content of alliin increased by 28.48%, while the levels of abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), and gibberellin (GA) increased by 15.82%, 12.94%, 32.34%, and 48.13%, respectively. Additionally, the activities of alliinase, superoxide dismutase (SOD), and catalase (CAT) were enhanced by 7.93%, 4.48%, and 19.74%, respectively. Moreover, the application of sulfur and nitrogen significantly reduced the malondialdehyde (MDA) content and peroxidase (POD) activity in garlic bulbs by 29.66% and 9.42%, respectively, thereby improving garlic's adaptability and growth potential. Transcriptomic analysis revealed differentially expressed genes in several key pathways, including plant hormone signal transduction, RNA degradation, glutathione metabolism, amino acid biosynthesis, and glycerophospholipid metabolism. Metabolomic analysis identified 80 differentially abundant metabolites primarily consisting of amino acids, indole carboxylic acids, and fatty acids. The integrated transcriptomic and metabolomic analyses highlighted the pivotal roles of glutathione metabolism, glycerophospholipid metabolism, and amino acid biosynthesis pathways in the synergistic effects of sulfur and nitrogen. This study not only provides critical scientific evidence for understanding the mechanisms underlying the nitrogen–sulfur interaction's impact on the yield and quality of garlic but also offers a scientific basis for optimizing nutrient management strategies to enhance garlic yield and quality. [ABSTRACT FROM AUTHOR]

Groundwater pollution in intensive horticultural areas is becoming an increasingly important problem. Over-fertilization of these crops, combined with poor irrigation management, leads to groundwater contamination through leaching. Previous research on the effect of N on sweet peppers grown in greenhouses is abundant, but data on outdoor cultivation, especially considering variety and site influences, are lacking. Therefore, this study evaluates nitrogen (N) fertilization in open-field processing-pepper crop in Extremadura, Spain to mitigate this environmental impact. Field trials were conducted in 2020, 2021, and 2022 to determine the optimum N fertilizer rate for processing peppers, with the aim of reducing environmental impacts such as nitrate leaching while maintaining crop yields. The trial consisted of applying different N doses, 0, 60, 120, and 180 kg N/ha in 2020 and 2021 and 0, 100, and 300 kg N/ha in 2022. There were four replications of each treatment, arranged in randomized blocks. Measurements included crop yield, biomass, intercepted photosynthetically active radiation (PAR), and canopy cover. The study also developed a critical nitrogen curve (CNC) to determine the minimum N concentration required for optimal growth. The commercial yield results showed that there were no significant differences between the two treatments with higher N inputs in the three years; therefore, the application of more than 120 kg N/ha did not significantly increase yield. Nitrogen-free treatments resulted in earlier fruit maturity, concentrating the harvest and reducing waste. In addition, excessive N application led to environmental problems such as groundwater contamination due to nitrate leaching. The study concludes that outdoor pepper crops in this region can achieve optimal yields with lower N rates (around 120 kg N/ha) compared to current practices, taking into account that initial soil N values were higher than 100 kg N/ha, thereby reducing environmental risks and fertilizer costs. It also established relationships between biomass, canopy cover, and N uptake to improve fertilization strategies. These data support future crop modeling and sustainable fertilization practices. [ABSTRACT FROM AUTHOR]

In‐stream biogeochemical processing, typically associated with base flow conditions, has recently been assessed at higher discharges, aided by high frequency monitoring. However, the potential for nutrient and carbon processing is still largely unknown in streams impacted by agriculture, representing major pathways for eutrophication and diffuse pollution. In this study, we measured solute concentrations and gross primary productivity (GPP) and ecosystem respiration (ER) to infer nitrate (NO3−) and dissolved organic carbon (DOC) supply and demand across contrasting hydrological conditions. As expected, solute supply greatly surpassed in‐stream biological demand for both NO3− and DOC for intermediate to large discharges. However, during four consecutive weeks in summer, lowered NO3− supply and high metabolic activity led to a 60% and 31% reduction in stream NO3− and DOC export. We also compared metabolism‐discharge versus solute concentration‐discharge patterns during storm events to better understand biogeochemical responses to high flows. Metabolic rates showed a contrasting response to storm events: ER increased while GPP decreased following declines in NO3− concentrations. The positive correlation between GPP and NO3− concentrations suggests that GPP suppression can be partially attributed to decreased NO3− availability during storm events. This study supports the idea that agricultural streams have a limited capacity to biologically process DOC and NO3−. However, it also emphasizes that the balance between supply and demand can vary from severe saturation to limitation, depending on seasonal fluctuations in discharge and metabolic activity, highlighting the crucial role of mitigating pollution at its source during hydrologically active periods to improve water quality. Plain Language Summary: To understand the overall capacity for water‐living organisms to reduce downstream export of pollutants (i.e., nitrogen and carbon), it is necessary to measure biological uptake rates (demand) together with pollutant loads (supply) across seasons and varying stream flow. However, the role of biological nitrogen and carbon processing has been less explored in streams impacted by high nutrient inputs from agriculture, especially during higher flows. Based on 2‐year monitoring of an agricultural stream, we argue that biological demand plays only a minor and temporary role for reducing nitrogen and carbon exports in these systems, which occurred only during summer when stream flow decreased and biological activity peaked. Although storm events occurred in periods with overall low biological activity, stormflow peaks consistently increased productivity of in‐stream bacteria and invertebrates, but decreased productivity of plants and algae. This study supports the idea that biological organisms in agricultural streams have a limited capacity to reduce nitrogen and carbon exports. However, it also shows that biological nitrogen availability can vary from severe saturation to limitation, depending on seasonal differences in stream flow and biological activity. Key Points: Supply:demand ratios show that nitrate and dissolved organic carbon supply typically overwhelm biological demand in an agricultural streamEvidence for biological nitrate limitation occurred during summer low flow and metabolic peak, despite high nitrate loading on annual termStorm events consistently stimulated in‐stream ecosystem respiration but suppressed gross primary production [ABSTRACT FROM AUTHOR]

Purpose: Magnesium hydroxide nanoparticles (Mg(OH)2 NPs) have emerged as promising candidates for environmental remediation, owing to their effectiveness in addressing diverse pollutants within soil and water systems. In this study, the changes of sediment properties and the responses of indigenous bacteria to black-odorous sediment amended with Mg(OH)2 NPs were investigated. Methods: Mg(OH)2 NPs were used to amend the black-odorous contaminated sediment, and the physicochemical properties, sulfide and heavy metal contents, enzyme activities of the sediment, and indigenous bacterial community parameters were determined. Results: Mg(OH)2 NPs significantly altered the sediment physicochemical properties, enzymatic activities, and bacterial community composition of the sediment. The pH value and total phosphorus contents increased, whereas total nitrogen and total organic carbon content decreased. The sulfide content significantly decreased with injection treatment, surpassing the effect elicited by the mixed addition mode. Dehydrogenase activity was significantly enhanced, whereas urease and alkaline phosphatase activities were evidently inhibited. Bacterial 16S rRNA gene copy numbers in the surface-layer sediment treated with Mg(OH)2 NPs increased by 267.86% (mixed) and 338.45% (injection) after a 60-day incubation period. The abundances of the dominant phyla and genera identified in the sediment increased under Mg(OH)2 NP treatment, particularly those involved in sulfur and nitrogen metabolism. Conclusion: Mg(OH)2 nanoparticles directly or indirectly affect the indigenous bacterial community through changes in the sediment physicochemical properties, heavy metal contents, and enzyme activities. These findings contribute to the development of more targeted and effective methods for mitigating sediment pollution and restoring ecosystem health. [ABSTRACT FROM AUTHOR]

Strength weakening exists in high-strength steel welds. Most of the researches focus on the composition of welding wire to regulate the weld strength. This article aims to study the role of nitrogen in steel welding by changing the proportion of nitrogen in the protective gas. By adding oxygen, explore the effect of activated nitrogen arc on the weld microstructure and mechanical properties of high-strength steel. Pulsed melt inert-gas welding (PMIG) technology is used to weld high-strength steel, and explore the impact on mechanical properties under activated nitrogen arc conditions. The PMIG welding process is adopted on high-strength steel, and an activated nitrogen arc is formed by Ar + N + O. The results show that under the condition of low heat input, using ER307Mo welding wire, the microstructure of the weld zone is uniform, and the grain is small. With the increase in nitrogen ratio, the actual welding current value decreases, the actual voltage value increases, the nitrogen decomposition reduces the arc energy and the solid nitrogen content of the weld increases. When the nitrogen ratio reaches 30% (vol.%) and O2 is 2.5% (vol.%), the nitrogen content reaches the maximum value, which is 0.5% (wt.%). The tensile strength reaches 970 MPa. The use of activated nitrogen arc welding can effectively increase the nitrogen content of the weld, promote the solid solution of nitrogen elements, refine the grain, and effectively improve the mechanical properties of the weld of high-strength steel. [ABSTRACT FROM AUTHOR]

Membrane inlet mass spectrometry (MIMS) provides detailed measures of dissolved 28,29,30N2, O2, and argon (Ar) for estimating important gas fluxes and concentrations in aquatic ecosystems. Previous studies demonstrated a large O2 scavenging effect while using a MIMS, where varying concentrations of O2 can affect measured N2 : Ar because O2 interacts with N2 in the ion source to produce NO+ (m/z = 30), potentially decreasing the detected current for 28,29N2 and increasing the detected current for 30N2. A common solution is to use a muffle furnace heated to 600°C with a copper reduction column to reduce the concentration of O2 to minimal levels and accurately measure 28,29,30N2. However, this solution eliminates the detection of O2 in environmental samples, which is a major benefit of using a MIMS. We questioned whether the MIMS was sensitive enough to provide accurate O2 estimates when using the furnace and whether the O2 scavenging effect was real and consistent among MIMS. We conducted four separate experiments on three different MIMS to test the O2 scavenging effect and the potential detection of O2 when using a MIMS with furnace. The furnace removed ~ 99% of O2, and O2 scavenging had little to no detectable effect on N2 : Ar and an unclear effect on 29N2 : 28N2, but increased 30N2 : 28N2. In most cases, accurate O2 data could be retrieved despite using the furnace. The need for O2 reduction may be limited to measuring accurate 30N2 : 28N2 in isotope pairing studies, but without substantial loss of MIMS measurements used to describe O2 dynamics. [ABSTRACT FROM AUTHOR]

Introduction: On intensive grassland dairy farms in high rainfall areas with poorly drained soils, networks of open drainage channels linked to in-field drainage systems are needed to enable farm operations. Nitrogen and phosphorus point and diffuse sources may be connected to this open drainage channel network along surface and subsurface pathways, with negative impacts upon delivery to the downstream aquatic system. Methods: This study developed a semi-quantitative risk assessment model by: (1) selecting parameters (categorical or continuous) representing the nutrient transfer continuum and (2) scoring (relative magnitude and impact) the risk of nutrient source connectivity and delivery for every open drainage channel section across seven dairy farms. Results and Discussion: A Risk Index Classification System consisting of low, medium, high, or very high-risk class was developed, with high or above requiring a mitigation plan. Results showed that 23%, 68%, 9% and 0% of all open drainage channels on study farms were identified as low, moderate, high and very highrisk, respectively. A range from 2% to 25% per farm of the open drainage channels was classified as high-risk that potentially needed mitigation, although none was identified as very high-risk. Two-thirds of the high-risk open drainage channels were connected to the farmyards, with potential for high nutrient loss from point sources. A combined approach of source management and targeted breaking of the pathway (e.g., in-channel filters, water diversion bars) may help minimise nutrient losses from high risk open drainage channels on poorly draining soils. [ABSTRACT FROM AUTHOR]

The present study aimed to understand the effect of nitrogen on the carbide precipitation and its influence on pitting corrosion of shielded metal arc welded high nitrogen 316SS weld. Nitrogen addition to weld reduces Cr availability sites in ferrite and enhances Cr in nearby austenite. Although higher carbon and continuous ferrite with ferritic austenitic mode exist, the changes in the degree of sensitisation were avoided at all the stages, and marginal changes in pitting potential (Epit) at 898 K/100 h and 998 K/24 h were observed. Nitrogen addition to weld further reduced the number of stable pits in ferrite and austenite, and the protectiveness of passive film was affected by nitrogen in ferrite and austenite, which affected pit propagation. This results in stable pits in ferrite and austenite, which affects pit propagation during thermal ageing. [ABSTRACT FROM AUTHOR]

Tidal marshes provide numerous ecosystem services, but are threatened by recent increases in global sea level rise (SLR). Marsh restoration and creation are important strategies for mitigating marsh loss, restoring ecosystem services, increasing coastal community resilience, and providing much needed habitat for threatened species. Dredged material resulting from navigation channel maintenance can provide a substrate for these restoration projects. Few studies, however, have addressed the sustainability of these marshes. The Paul S. Sarbanes Ecosystem Restoration Project at Poplar Island, where fine-grained, nutrient-rich dredged material from upper Chesapeake Bay is being used to create > 302 ha of tidal marshes, provides a case study. The low supply of inorganic sediment is counteracted by abundant nutrients, stimulating high rates of organic matter production and elevation change. Using > 10 years of data from 39 surface elevation tables, we found that the mean low marsh rate of elevation change (7.7 ± 3.21 mm year−1) was double the mean high marsh rate (3.6 ± 0.47 mm year−1) and exceeded the natural reference marsh (3.0 ± 2.28 mm year−1) and relative SLR (5.7 mm year−1). By stimulating organic matter production, the high nutrient substrate appears to offset the low inorganic sediment inputs in mid-Chesapeake Bay. Spatial variability was correlated with initial elevation, but was also influenced by local factors that may affect sediment redistribution within the marshes. [ABSTRACT FROM AUTHOR]

We report results of studies of luminescence decay processes in excited states of nitrogen molecules and ions in gas mixtures with hydrocarbon molecules. Use is made of emission spectroscopy methods to perform measurements. Nitrogen molecules N2 and nitrogen molecular ions are excited to the C3Πu state and the state, respectively, by a repeated high-voltage nanosecond discharge in the gas mixture in question. As a result of processing the data obtained by varying the composition of the gas mixtures and their pressure (1–20 Torr), the quenching rate constants of the excited states of nitrogen N2(C3Πu) and in collisions with hydrocarbon molecules CH4, C2H6, and C3H8 are determined. For the first time, the values of the quenching rate constants are obtained for a mixture of nitrogen and propane, as well as for the 3 → 7 transition of the emission band system N2(C3Πu → B3Πg) of a nitrogen–methane mixture. [ABSTRACT FROM AUTHOR]

Marine biological nitrogen fixation (BNF) is crucial for introducing "new nitrogen" into the oceans. Over the past 30 years, numerous laboratory and on-board culture experiments have been conducted studying the effects of nutrients such as total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), and dissolved iron (DFe) on marine diazotrophs such as Braarudosphaera bigelowii (B. bigelowii), Trichodesmium, Crocosphaera and noncyanobacterial diazotrophs (NCDs). Most studies concluded that elevated dissolved inorganic nitrogen levels inhibit nitrogen fixation in Trichodesmium, promote its growth, and have minimal effect on B. bigelowii. The impact on NCDs is unclear. Moreover, elevated dissolved inorganic phosphorus (DIP) levels can promote individual growth, population growth, and nitrogen fixation in most diazotrophs in P-limited marine environments. Dissolved organic phosphorus is a potential phosphorous source for diazotrophs in low-DIP environments. Elevated DFe can promote population growth and nitrogen fixation in diazotrophs in Fe-limited marine environments. At present, most diazotrophs have yet to achieve pure culture. Moreover, the effect of nutrients on diazotrophs is mainly limited to the study of a single nutrient, which cannot accurately reflect the actual Marine environment where diazotrophs live. As a result, our understanding of the effect of nutrients on diazotrophs is still insufficient. Future research focusing on the issues above and the development of innovative technologies and methodologies to investigate the impact of marine BNF is highly recommended, which will allow for a more precise assessment of the impact of marine BNF on global primary productivity while providing a scientific foundation for rational evaluation of ocean CO2 uptake and emissions. [ABSTRACT FROM AUTHOR]

Grain filling is a critical process for improving crop production under adverse conditions caused by climate change. Here, using a quantitative method, we quantified post-anthesis source–sink relationships of a large dataset to assess the contribution of remobilized pre-anthesis assimilates to grain growth for both biomass and nitrogen. The dataset came from 13 years of semi-controlled field experimentation, in which six bread wheat genotypes were grown at plot scale under contrasting temperature, water, and nitrogen regimes. On average, grain biomass was ~10% higher than post-anthesis above-ground biomass accumulation across regimes and genotypes. Overall, the estimated relative contribution (%) of remobilized assimilates to grain biomass became increasingly significant with increasing stress intensity, ranging from virtually nil to 100%. This percentage was altered more by water and nitrogen regimes than by temperature, indicating the greater impact of water or nitrogen regimes relative to high temperatures under our experimental conditions. Relationships between grain nitrogen demand and post-anthesis nitrogen uptake were generally insensitive to environmental conditions, as there was always significant remobilization of nitrogen from vegetative organs, which helped to stabilize the amount of grain nitrogen. Moreover, variations in the relative contribution of remobilized assimilates with environmental variables were genotype dependent. Our analysis provides an overall picture of post-anthesis source–sink relationships and pre-anthesis assimilate contributions to grain filling across (non-)environmental factors, and highlights that designing wheat adaptation to climate change should account for complex multifactor interactions. [ABSTRACT FROM AUTHOR]

Metal single‐atoms implanted on nitrogen‐doped carbon matrices (M‐NxCs) can effectively adjust local surface electrons and polarization relaxation through coordination structures to significantly enhance the electromagnetic wave (EMW) absorption properties of the materials. However, the precise construction of the geometric and electronic structures of metal single atoms and the discovery of the structure‐absorption relationship at the atomic level confront a huge challenge. Herein, this work summarizes the latest progress in metal single‐atom engineering of EMW absorbing materials via a comprehensive analysis of M‐NxCs in terms of design principles, modulation strategies, and structure‐performance correlations. Subsequently, it highlights the recent progress of several typical M‐NxCs as the EMW absorbing materials, aiming to achieve a complete understanding of the physical effects and atomic‐level absorption mechanisms. Finally, current key challenge and future directions of M‐NxCs are presented by focusing on the electromagnetic functional materials. This work provides new insights for the development of atomically dispersed absorbing materials for efficient electromagnetic response functionalities. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the nitrogen fertilisation supply method on wheat silage fermentation parameters and nutritional value. Eighteen experimental plots were used in a randomised block design to assess the following treatments: (1) control (CON): crop without nitrogen fertilisation; (2) surface (SUR): 100 kg/ha N during the crop, applied in surface; (3) furrows (FUR): 100 kg/ha N during the crop, applied in furrows during the seeding. Whole plants were manually harvested at 5 cm height 83 days after the sowing. One experimental silo (PVC tubes) was produced for each agronomical plot and stored for 69 days. In general, N fertilisation did not affect silage pH and ammonia-N (NH3-N) content, but silos FUR had less NH3-N than those with SUR. Fertilisation increased the CP and DM content and reduced starch in the silage. FUR increased DM and reduced CP compared to SUR. Furthermore, N fertilisation increased non-protein nitrogen and decreased in vitro degradation of DM and OM. Fertilisation methods did not affect N fractions in silage or in vitro degradation. Therefore, N fertilisation, especially FUR, reduces NH3-N and CP and increases DM content of silage, but decreases in vitro DM and OM degradation. [ABSTRACT FROM AUTHOR]

Introduction: This study investigated the combined effects of molybdenum (Mo) and nitrogen (N) fertilization on N metabolism and amino acid content in the leaves of flue-cured tobacco (Nicotiana tabacum L.) during its mature stage through a pot experiment. Methods: Different application levels of Mo (0, 0.15, 0.30 mg/kg soil) and N (0.06, 0.24, 0.42 g/kg soil) were set to observe and analyze changes in leaf quality, N, and amino acid content in the tobacco plants. Results: The results revealed that the N fertilizer application level exhibited a primary effect on regulating the total nitrogen, nitrate nitrogen, soluble protein, and amino acid nitrogen concentrations within tobacco leaves, while the effectiveness of Mo fertilization was influenced by the level of N applied. Specifically, under the conditions of 0.24 g/kg soil N and 0.30 mg/kg soil Mo application, the N content, N accumulation, and dry matter mass of the tobacco plants increased significantly by 110%, 204%, and 48%, respectively. Concurrently, nitrate reductase activity increased by 107-fold, and the nitrate nitrogen content was relatively low, contributing to enhanced tobacco yield and safety. Moreover, this treatment led to a notable (170%) increase in free amino acid nitrogen content, with minimal impact on total amino acids and soluble proteins. Notably, it effectively increased the content of free amino acids beneficial to the sensory quality of tobacco (such as histidine, arginine, aspartic acid, isoleucine, and glutamic acid) without reducing the total amino acid content, while simultaneously reducing other amino acids that might affect quality. Therefore, the combined application of 0.30 mg/kg soil Mo and 0.24 g/kg soil N specifically optimized the amino acid composition in tobacco leaves, positively impacting overall quality and market competitiveness. Discussion: This study provides a theoretical basis for the rational application of Mo fertilizer in Mo-deficient areas to improve the yield and quality of fluecured tobacco. [ABSTRACT FROM AUTHOR]

Background: The purpose of the study was to measure the degree of conversion (DC) of direct-printed aligners (DPA) that were post-cured under ambient and nitrogen atmosphere at specific time intervals and investigate the kinetics of polymerization reaction of this material. Methods: A total of 48 aligners were produced in 4 printing series by a 3D printer with TC-85DAC resin (Graphy Inc). From each series of printing, 12 aligners were included. The aligners were divided into two groups according to their post-curing conditions. One group was post-cured under ambient air with the presence of oxygen and the other under a nitrogen atmosphere, both using the same UV post-curing unit recommended by the company. The aligners were post-cured at six different time intervals: 1, 2, 3, 5, 10, and 20 min. Each time interval included 8 aligners, with 2 aligners from each series. The DC of the cured aligners was measured by means of attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) through acquisition of the respective spectra for each UV-curing condition. Statistical analysis was performed to compare the results and differences within each atmosphere post-curing protocol, as well as between the different selected atmosphere conditions. Statistical significance level was set at p-value ≤ 0.05. Results: Pairwise analysis between post-curing protocols showed statistically significant differences only at the first minute of polymerization. Post-curing with nitrogen did not yield statistically significant results across different time intervals. Post-curing in ambient air showed some significant differences on the 1st and 2nd minute of the post-curing process. Conclusions: Almost complete double bond conversion was observed. Significant differences were observed only during the first minute of polymerization under the nitrogen atmosphere. [ABSTRACT FROM AUTHOR]

Intercropping is a prevalent soil management strategy within orchards, whereas it is unclear how inoculation with arbuscular mycorrhizal (AM) fungi and intercropping affect tree growth, soil properties, and rhizosphere metabolite profiles. This study investigated the effects of inoculation with Diversispora spurca and intercropping with hairy vetch (Vicia villosa) on biomass production, soil available nutrients, water-stable aggregate (WSA) distribution, phosphatase activity, and secondary metabolite profiles in walnuts (Juglans regia). The intercropping only elevated soil nitrate N levels and WSA distribution at the 0.5–2 mm size, and also triggered 2159 differential metabolites (1378 up-regulated and 781 down-regulated), with armillaramide as the most prominently up-regulated metabolite, followed by the substance diminished upon D. spurca inoculation. Conversely, D. spurca inoculation increased walnut biomass, WSA distribution across the 0.25 − 2 mm size, and acid and neutral phosphatase activities, as well as triggered 2489 differential metabolites (897 up-regulated and 1592 down-regulated), with pteroside D being highest up-regulated differential metabolite, allowing a competitive advantage to AM plants in combating soil pathogens. Despite significantly suppressing root AM fungal colonization and biomass production in AM walnuts, intercropping significantly increased soil ammonium and nitrate N levels in AM walnuts as well as WSAs at the 1–4 mm size, exhibiting a synergistic effect. Flavone and flavonol biosynthesis and pyruvate metabolism were simultaneously involved following AM inoculation or intercropping. Co-application of AM inoculation and intercropping triggered 1006 differential metabolites, with urocanic acid being the most up-regulated metabolite, although it decreased following AM inoculation, suggesting the involvement of mycorrhizal hyphae in soil histidine uptake. Under intercropping, AM inoculation elicited 418 differential metabolites, with the most up-regulated metabolite being implicated in flavonoid pathways. AM inoculation primarily triggered the biosynthesis of unsaturated fatty acids, regardless of intercropping or not, implying a potential increase in unsaturated fatty acid contents of walnut kernels. It concluded that AM inoculation and intercropping interactively affected walnut growth, soil attributes, and soil microenvironment. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) has received considerable attention as a major reduced nitrogen. However, accurate estimates of the deposition amount are difficult due to its complex behavior characterized by bidirectional exchange between the atmosphere and the surface. We observed the vertical profile of NH3 concentration in a deciduous forest in Japan for 1 year to further advance the studies on NH3 bidirectional exchange in Asia, especially focusing on the process near the forest floor. The observation period lasted from September 29, 2020, to September 28, 2021, including leafy and leafless periods. Using the denuder sampling technique, we measured NH3 concentration in the forest at three heights (above the forest canopy, 30 m, and near the forest floor, 2 m and 0.2 m). NH3 concentrations tended to be highest at the top of the canopy (30 m). Focusing on the concentration near the forest floor, the concentrations at 0.2 m were frequently higher than those at 2 m regardless of the leafy and leafless period, thus suggesting NH3 emissions from the forest floor. NH3 concentration near the forest floor showed strong positive correlations with air temperature during the leafy period. The NH3 emissions from the forest floor during the leafy period were possibly due to the decomposition of leaf litter with increased air temperature. The decrease in leaf area index might induced the increase in NH3 concentration and emission. NH3 emission during the leafless period was also possibly dependent on the state of the deposition surface, apart from air temperature, relative humidity, and leaf area index. [ABSTRACT FROM AUTHOR]

SUMMARY Plants depend heavily on soil nutrients for growth, development and defence. Nutrient availability is crucial not only for sustaining vital biochemical processes but also for mounting effective defences against a diverse array of pathogens. Macronutrients such as nitrogen, phosphorus and potassium significantly influence plant defence mechanisms by providing essential building blocks for the synthesis of defence compounds, immune signalling and physiological responses like stomatal regulation. Micronutrients like zinc, copper and iron are essential for balancing reactive oxygen species and other reactive compounds in plant immune responses. Although substantial circumstantial evidence links nutrient availability to plant defence, the molecular mechanisms underlying this process have only recently started to be understood. This review focuses on summarizing recent advances in understanding the molecular mechanisms by which nitrogen, phosphorus and iron interact with plant defence mechanisms and explores the potential for engineering nutritional immunity in crops to enhance their resilience against pathogens. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION Cereal–legume intercropping provides a solution for achieving global food security, but the mechanism of greenhouse gas emissions and net ecosystem economic benefits of maize–soybean relay intercropping are poorly understood. Hence, we conducted a two‐factor experiment to investigate the effects of cropping systems, containing maize–soybean relay intercropping (IMS), monoculture maize (M) and monoculture soybean (S), as well as three nitrogen levels at 0 (N0), 180 (N1), 240 (N2) kg N ha−1 on crop grain yield, greenhouse gas emissions, soil carbon stock and net ecosystem economic benefit (NEEB).The average grain yield of IMS (7.7 t ha−1) increased by 28.5% and 242.4% compared with M (6.0 t ha−1) and S (2.2 t ha−1). The land equivalent ratio (LER) of IMS was 2.0, which was mainly contributed by maize (partial LER: 1.2) rather than soybean (partial LER: 0.8). Although the total grain yield of IMS remarkably enhanced by 43.6% and 45.5% in N1 and N2 contrast in N0, the LER was 37.5% and 38.6% lower in N1 and N2 than in N0. The net global warming potential (GWP) of maize and soybean was 11.6% and 1.8% lower in IMS than in the corresponding monoculture, which resulted from a decline in GWP and enhanced soil organic carbon stock rate. Moreover, NEEB was 133.5% higher in IMS (14 032.0 Chinese yuan per year) than in M, mainly resulting from an increase in total economic gains and a decline in GWP cost. A more robust response in yield gain rather than total costs to N inputs of IMS led to 46.8% and 48.3% higher NEEB in N1 and N2 than in N0.Maize–soybean relay intercropping with 180 kg N ha−1 application can obtain yield advantages without raising environmental costs, which provides an approach to achieving sustainable agricultural production. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Due to the highly reductive capacity of nano zero-valent iron (nZVI) nanoparticles, the reduction of nitrate (NO3−-N) is prone to produce ammonia nitrogen (NH4+-N) as a by-product and has low selectivity for nitrogen gas (N2). Water and dissolved oxygen (DO) in the solution consume electrons from nZVI, decreasing the efficiency of NO3−-N reduction. In order to overcome the drawbacks of plain nZVI being used to remove NO3−-N pollution, nZVI-based multifunctional materials have been constructed to realize the selective conversion of NO3−-N to N2 as well as the efficient removal of NO3−-N. Therefore, advanced research on the reduction of NO3−-N by nZVI-based composites has been comprehensively reviewed. Strategies to improve NO3−-N reduction efficiency and N2 selectivity are proposed. Moreover, the shortcomings of iron-based nanomaterials in NO3−-N pollution control have been summarized, and some suggestions for future research directions provided. [ABSTRACT FROM AUTHOR]

First-principles simulations are conducted to explore the structural stability, electronic properties, and optical responses of pristine and boron- or nitrogen-doped monolayers graphene. The computed electronic density of states revealed that the substitutional doping of boron impurity atoms on monolayer graphene (MLG) shifts the Dirac point upward, although the substitution of nitrogen impurity atoms in graphene pushes the Dirac point downward the Fermi level. This could exhibit that upon the doping of MLG with boron or nitrogen, respectively, p-type or n-type semimetal is acquired. The overall optical spectral properties of the substituted graphene with boron or nitrogen atoms are simulated and compared with the optical spectra results of pure graphene. The optical features of pristine and doped MLG are determined by taking the interband and intra-band transitions into account ranging from the far-infrared to the ultraviolet regime of the electromagnetic radiation. A remarkable red shift in the optical spectra of the doped MLG towards the visible regime of radiation is established. An enhanced reflectivity illustrated that concentration-dependent optical properties of boron and nitrogen-doped MLG happen at lower electromagnetic radiation regimes. In addition, we explored the thermoelectric behaviors of the pristine/doped graphene monolayers with 4 × 4 supercells. We found a significant improvement in the electrical conductivity of graphene when doped with boron or nitrogen impurities. However, an increase in the electrical conductivity has textured a decrease in the Seebeck coefficients. Improvement in the electrical conductivity is attributed to an interesting effect on the graphene monolayers' power factor (PF). These findings indicate a positive impact of the dopants on the thermoelectric properties of graphene monolayers and reveal that they are potential materials for thermoelectric applications and nanodevices. [ABSTRACT FROM AUTHOR]

The bioavailable nitrogen fixed by diazotrophs is critical for sustaining productivity in the oligotrophic ocean. Despite this, understanding how diazotroph-derived nitrogen integrates into the nitrogen cycle within the euphotic zone remains unknown. Here, we investigated nitrogen fixation rates in the particulate and dissolved fractions within the euphotic zone of the North Pacific Subtropical Gyre. Our findings reveal the proportion of nitrogen fixation rates in the dissolved fraction increases with depth. Light manipulation experiments uncover that reduced light levels can stimulate the net release of diazotroph-derived nitrogen, aligning with our depth-related observations. Furthermore, we identify two distinct transfer pathways vertically associated with light-driven ecological niches. Specifically, the released diazotroph-derived nitrogen is transferred to non-diazotrophic plankton in the upper layers. Meanwhile, in the lower layers, it contributes to the nitrification process. Our results underscore the high bioavailability of diazotroph-derived nitrogen and its rapid integration into the nitrogen cycle through multiple pathways within the well-lit ocean. New study finds diazotroph-derived nitrogen is utilized by phytoplankton in upper euphotic zone, while below, it is used by nitrifiers. The newly identified pathways reveal the marine nitrogen cycle may be more interconnected than previously recognized. [ABSTRACT FROM AUTHOR]

The fabrication of solid solutions represents a compelling approach to modulating the physicochemical properties of materials. In this study, we achieved the successful synthesis of solid solutions comprising SrTiO3 and SrTaO2N (denoted as (SrTiO3)1‐x‐(SrTaO2N)x, 0≤x≤1) using the magnesium powder‐assisted nitridation method. The absorption edge of (SrTiO3)1‐x‐(SrTaO2N)x is tunable from 500 to 600 nm. The conduction band minimum (CBM) of (SrTiO3)1‐x‐(SrTaO2N)x comprises the Ti 3d orbitals and the Ta 5d orbitals, while the valence band maximum (VBM) consists of the O 2p and N 2p orbitals. The microstructure of the (SrTiO3)1‐x‐(SrTaO2N)x consists of small nanoparticles, exhibiting a larger specific surface area than the parent compounds of SrTiO3 and SrTaO2N. In the photocatalytic hydrogen evolution reaction (HER) with sacrificial reagents, the activity of solid solutions is notably superior to that of nitrogen‐doped SrTiO3 and SrTaO2N. This superiority is mainly attributed to its broad light absorption range and high charge separation efficiency, which indicates its potential as a promising photocatalytic material. Moreover, the magnesium powder‐assisted nitridation method exhibits obvious advantages for the synthesis of oxynitrides and bears instructional significance for the synthesis of other nitrogen‐containing compounds and even sulfur‐containing compounds. [ABSTRACT FROM AUTHOR]

Embracing CO2 mitigation strategies, such as state-of-the-art CO2 capture technologies, is essential for effectively reducing atmospheric carbon levels and advancing global efforts toward a more sustainable future. In this context, adsorption sequestering techniques utilising carbon materials have emerged as promising candidates for CO2 capture. These materials have been extensively researched with a range of tuning methods to optimise their physicochemical features. In this study, an alteration of the N-doped activated carbon was successfully performed, utilizing tea residue as the carbon precursor and ammonia as the nitrogen source, facilitated through an impregnation procedure. With the objective of discovering the effect of diverse activation parameters on prepared adsorbent physicochemical properties, several selections of activating agents (AA) were investigated: KOH, H3PO4, ZnCl2, and NaOH, together with broad thermal activation temperature from 873 to 1173 K. The best-performed adsorbents from the respective AC group were subjected to several characterisation analyses and found to the enhanced structural features, heteroatom doped-rich surface (i.e. N and O); together with AA-induced metal/mineral functionalization, the NaOH-used AC (NAC-N-1173) was the optimum-performed adsorbent with a promising 4.12 mmol/g CO2 uptake capacity, higher than other prepared adsorbent including N-doped tea residue-derived char and commercialized AC with 175 and 325% higher, respectively. [ABSTRACT FROM AUTHOR]

Single‐site molecular electrocatalysts, especially those that perform catalytic conversion of N2 to NH3 under mild conditions, are highly desirable to derive fundamental structure‐activity relations and as potential alternatives to the current energy‐consuming Haber‐Bosch ammonia production process. Combining theoretical calculations with experimental evidence, it has been shown that easily reducible cobalt porphyrins catalyze the six‐electron, six‐proton reduction of dinitrogen to NH3 at neutral pH and under ambient conditions. Two easily reducible N‐fused cobalt porphyrins – CoNHF and CoNHF(Br)2 – reveal NRR activity with Faradic efficiencies between 6–7.5 % with ammonia yield rates of 300–340 μmol g−1 h−1. Contrary to this, much harder‐to‐reduce N‐fused porphyrins – CoNHF(Ph)2 and CoNHF(PE)2 – reveal no NRR activity. The present study highlights the significance of tuning the redox and structural properties of single‐site NRR electrocatalysts for improved NRR activity under mild conditions. [ABSTRACT FROM AUTHOR]

The generalized k-connectivity of a graph G, denoted by κk(G), is the minimum number of internally edge disjoint S-trees for any S ⊆ V (G) with |S| = k. The generalized k-connectivity of a graph is a natural extension of the classical connectivity and can be served as an essential parameter for measuring reliability and fault tolerance of the network. Hierarchical interconnection networks (HIN’s) are very important in applications related to the modern interconnection networks since they posses many desirable properties. In this paper, we firstly introduce a family of regular networks HGn that can be obtained from Gn1 ∪ G n2 ∪⋯ ∪ G nt by adding a matching, where Gni and Gnj are vertex-disjoint subgraphs and each Gni is isomorphic to a given graph Gn (1 ≤ i < j ≤ t). Then we determine the generalized 3-connectivity of HGn. As applications of the main result, the generalized 3-connectivity of some HIN’s, such as the hierarchical star network HSn, the hierarchical cubic network HCNn and the hierarchical folded hypercube HFQn, can be determined immediately. [ABSTRACT FROM AUTHOR]

Silicon (Si) application may affect the plant response to nitrogen (N), possibly by changing the uptake, concentration, and partitioning of nutrients in plant tissues; however, this has not yet been proven in Arabica coffee plants. The effects of Si application methods [no Si, soil-applied soluble Si (168 mg Si L−1), and foliar-applied soluble Si (two application of 2 mg Si plant−1)] and N levels (0 and 80 mg N L−1) on biomass production and partitioning and uptake, partitioning, and stoichiometry of nutrients and Si in young Arabica coffee plants grown under greenhouse conditions were evaluated. Nitrogen fertilization increased the biomass production and uptake of all nutrients; however, reduced the concentrations of K, Ca, Mg, S, Mn, and Si in the leaves, Si in the stems, and K, Mg, and S in the roots of coffee plants as a dilution effect. In the presence of N, soil-applied Si increased the concentrations of Zn in the leaves and Ca and Si in the stems, the uptake of K, S, and Si, and the Si:N ratio. Foliar-applied Si increased the concentrations of N, P, K, and Zn in the leaves and Ca and Si in the stems, as well as the total uptake of K and Si and the Si:N ratio in coffee plants, being more evident in the N fertilization presence. This study unraveled that, especially when it was soil-applied, Si altered the nutrient uptake, allocation, and stoichiometric ratios with N, with a consequent increase in biomass production of young coffee plants fertilized with N. [ABSTRACT FROM AUTHOR]

Pig slurry can be used as an alternative source for nutrients, particularly nitrogen (N), for plants. However, after applying the pig slurry to the soil, gaseous loss of N this nutrient may occur, mainly in the form of ammonia. Hence this study aimed to evaluate the loss of N by volatilization after the application of pig slurry with an acidified pH. Ammonia volatilization was evaluated using pig slurry, with its pH modified to 5.0 using four acids (sulfuric acid, citric acid, ascorbic acid, and acetic acid). Additionally, pig slurry with natural pH and a control were also used. The work was conducted in a greenhouse, and collectors were used to capture the volatilized ammonia in a static free semi-open chamber. The application of pig slurry with natural pH (7.19) resulted in 61% loss of ammonia, whereas acidification with ascorbic acid (pH 5.0) caused a loss of only 26%. The application of pig slurry with pH above 7.0 caused N loss, indicating that using acids to maintain a pH of 5.0–6.0 could be an alternative to reduce N loss by ammonia volatilization. [ABSTRACT FROM AUTHOR]

Developing high-efficiency non-noble metal catalysts for the oxygen reduction reaction (ORR) is paramount for sustainable energy conversion. In this study, we proposed a Cu, Fe co-doped zeolite imidazole framework (ZIF)-derived nitrogen-doped carbon nanotubes catalyst (Cu–Fe@CNTs/NC) obtained by hydrothermal method and pyrolysis. The electrochemical results showed that Cu–Fe@CNTs/NC exhibited favorable oxygen reduction performance and good stability under alkaline electrolyte. The incorporation of Cu and Fe bimetallic dopants promoted the carbon nanotubes growth on ZIF nanosheets, and the collaborative action of Cu and Fe enhanced its ORR catalytic activity. These findings provide an innovative way to prepare high active non-platinum ORR catalysts. In this study, a simple strategy was employed to modulate Fe loaded on ZIF nanosheets by Cu plates during hydrothermal process. The Cu–Fe@CNTs/NC catalysts obtained by pyrolysis of Cu, Fe co-doped on ZIF-derived nitrogen-doped carbon substrates exhibited excellent catalytic activity and stability. The half-wave potential of the ORR test was 0.87 V (vs. REH). Meanwhile, the Zn-air battery based on Cu–Fe@CNTs/NC catalyst as the cathode exhibited a power density of 167 mW cm−2 and a charge/discharge cycle stability that remained stable over 1000 cycles. The Cu flakes modulate the valence state of Fe during the hydrothermal process, and the displaced Cu atoms enter the ZIF lattice, which promotes the growth of nanotubes during the pyrolysis process, while the metal-N sites formed by the combination of Cu, Fe and nitrogen provide more reactive sites for ORR. [Display omitted] • Cu–Fe@CNTs/NC was prepared by simple hydrothermal method and pyrolysis. • Cu–Fe@CNTs/NC exhibited the excellent electrocatalytic activies (E 1/2 = 0.87 V vs. RHE) and stabilities for ORR. • Znic-air battery exhibit long cycle life and higher power density (167 mW cm−2) than commercial Pt/C. [ABSTRACT FROM AUTHOR]

Nitrogen-containing compounds such as imides and amides have been reported as efficient materials that promote ammonia decomposition over nonnoble metal catalysts. However, these compounds decompose in an air atmosphere and become inactive, which leads to difficulty in handling. Here, we focused on perovskite oxynitrides as air-stable and efficient supports for ammonia decomposition catalysts. Ni-loaded oxynitrides exhibited 2.5–18 times greater catalytic activity than did the corresponding oxide-supported Ni catalysts, even without noticeable differences in the Ni particle size and surface area of the supports. The catalytic performance of the Ni-loaded oxynitrides is well correlated with the nitrogen desorption temperature during N2 temperature-programmed desorption, which suggests that the lattice nitrogen in the oxynitride support rather than the Ni surface is the active site for ammonia decomposition. Furthermore, NH3 temperature-programmed surface reactions and density functional theory (DFT) calculations revealed that NH3 molecules are preferentially adsorbed on the nitrogen vacancy sites on the support surface rather than on the Ni surface. Thus, the ammonia decomposition reaction is facilitated by a vacancy-mediated reaction mechanism. Oxynitride-supported Ni catalysts exhibit much higher activity than oxide-supported Ni catalysts for ammonia decomposition reaction. Ammonia is activated at nitrogen vacancy sites on the surface of oxynitride in close vicinity to the supported Ni nanoparticles rather than on the Ni surface, and therefore the catalytic performance is dominated by ease of nitrogen vacancy formation on the catalyst surface. [ABSTRACT FROM AUTHOR]

Oxy-steam combustion is a new oxy-fuel combustion technology. This paper focuses on the NO emission characteristics during the combustion of SF (Shen Fu) coal in O2/N2 and O2/H2O mixtures. Experiments were performed in a drop-tube furnace. Combustion tests were carried out in O2/N2 and O2/H2O atmospheres for various O2 concentrations (21%, 30%, 40%, and 60%) at different temperatures (1173 K, 1273 K, and 1373 K). In addition, combustion experiments at different excess oxygen ratios (λ) were conducted in O2/N2 and O2/H2O atmospheres. The influences of the atmosphere, oxygen concentration, temperature, and excess oxygen ratio on NO emissions were analyzed. The results show that the NO concentrations of SF coal combustion in the 21% O2/79% H2O atmosphere were much lower than those in the 21% O2/79% N2 atmosphere at the three temperatures considered. This was because a large amount of NO was decomposed during the SF coal combustion in the O2/H2O atmospheres. The reasons for the decomposition of NO include the selective non-catalytic reaction (SNCR) mechanism and char's important role as a catalyst for the destruction of NO, either directly or by reacting with CO or H2. In oxy-steam combustion, the NO concentrations significantly increased with the increase in the oxygen concentration from 21 vol.% to 60 vol.% and the temperature from 1173 K to 1373 K. The excess oxygen ratio (λ) slightly impacted the NO emissions in the O2/H2O atmosphere. [ABSTRACT FROM AUTHOR]

Laminated (NbTaMoW)Nx films were prepared via co-sputtering. The sputtering variables were a substrate holder rotation speed of 2 and 10 rpm and a nitrogen flow ratio (fN2 = N2/(Ar + N2)) of 0.1, 0.2, and 0.4. The (NbTaMoW)Nx films fabricated at 30 rpm displayed columnar structures. The phase structures of the laminated (NbTaMoW)Nx films varied from multiple body-centered cubic phases to a nanocrystalline and a face-centered cubic phase as the fN2 increased from 0.1 to 0.2 and 0.4. The mechanical and tribological properties of the laminated (NbTaMoW)Nx films were evaluated. The laminated (NbTaMoW)Nx films deposited at an fN2 of 0.4 had hardnesses of 25.2 and 26.1 GPa when prepared at 2 and 10 rpm, respectively, lower than the value of 29.9 GPa for the columnar (NbTaMoW)Nx film prepared at an fN2 of 0.4 and 30 rpm. In contrast, the wear resistances of the laminated (NbTaMoW)Nx films were superior to those of the columnar (NbTaMoW)Nx films. [ABSTRACT FROM AUTHOR]

Employing drones and hyperspectral imagers for large-scale, precise evaluation of nitrogen (N) concentration in Carya cathayensis Sarg canopies is crucial for accurately managing nitrogen fertilization in C. cathayensis Sarg cultivation. This study gathered five sets of hyperspectral imagery data from C. cathayensis Sarg plantations across four distinct locations with varying environmental stresses using drones. The research assessed the canopy nitrogen concentration of C. cathayensis Sarg trees both during singular growth periods and throughout their entire growth cycles. The objective was to explore the influence of band combinations and spectral index formula configurations on the predictive capability of the hyperspectral indices (HIs) for canopy N concentration (CNC), optimize the performance between HIs and machine learning approaches, and validate the efficacy of optimized HI algorithms. The findings revealed the following: (i) Optimized HIs demonstrated optimal predictive performance during both singular growth periods and the full growth cycles of C. cathayensis Sarg. The most effective HI model for singular growth periods was the optimized–modified–normalized difference vegetation index (opt-mNDVI), achieving an adjusted coefficient of determination (R2) of 0.96 and a root mean square error (RMSE) of 0.71. For the entire growth cycle, the HI model, also opt-mNDVI, attained an R2 of 0.75 and an RMSE of 2.11; (ii) optimized band combinations substantially enhanced HIs' predictive performance by 16% to 71%, while the choice between three-band and two-band combinations influenced the predictive capacity of optimized HIs by 4% to 46%. Hence, utilizing optimized HIs combined with Unmanned Aerial Vehicle (UAV) hyperspectral imaging to evaluate nitrogen concentration in C. cathayensis Sarg trees under complex field conditions offers significant practical value. [ABSTRACT FROM AUTHOR]

Guar is a typical legume cash crop native to India. Guar beans are ever-rising in the market share at present. Among them, the guar gum of its seed endosperm has been mainly used in the oil exploration industry. Water-based fracturing fluid can be formulated to increase the permeability of oil-bearing strata during oil production. In addition, guar gum is also widely used in paper making, textiles, food, spices, drugs, as well as mining and metallurgical industries. The nutrient-rich green seeds of guar beans are edible for food vegetables, due to a large amount of protein and a small amount of fat. The plant can be used as fodder and green manure. However, the low supply of guar gum on the market cannot fully meet the broad market space. Only a small number of planting areas of guar beans are suitable for the cultivation of guar beans in the food industry. Among them, Xinjiang located in the northwestern inland arid zone is very similar to the unique geographic conditions for the production and cultivation of guar beans. The temperature and heat conditions are suitable for the origin of guar, rich in the light and heat resources under the soil and water environment, with the high temperature difference between day and night, due to the scarce rainfall and high evaporation. But the relatively small region of guar bean planting still remains so far. Therefore a broad prospect can be expected to optimize the water and nitrogen management for the high crop yield and efficient use of water and nitrogen. This study aims to explore the water and nitrogen mode suitable for drip irrigation of guar beans under film in the Xinjiang area of China. Four irrigation levels were set: W1:1170 m³/hm², W2:1 530 m³/hm², W3:1 890 m³/hm², W4: 2 250 m³/hm²; Two levels of nitrogen application were: N1:30 kg/hm², N2:50 kg/hm². A systematic investigation was made to clarify the effects of water and nitrogen interaction on the growth index, yield, water, and nitrogen use efficiency, as well as the quality of guar bean during drip irrigation under film. The results showed that the coupling effect of water and nitrogen shared a significant effect on the yield, irrigation water use efficiency, and partial factor productivity of nitrogen fertilizer (W3>W4>W2>W1). There was an increase in the plant height, stem diameter, dry matter accumulation, yield, water use efficiency, galactomannan, soluble sugar, and polysaccharide content of Guar bean under the N2 level, compared with the N1 level. Only the partial productivity of nitrogen fertilizer decreased slightly. Principal component and membership function analysis showed that the optimal treatment was achieved in the irrigation amount of 1 890 m³/hm² and the nitrogen application rate of 50 kg/hm²(W3N2). The finding can also provide a theoretical basis to promote the yield, water, and nitrogen use efficiency of Guar bean under mulched drip irrigation. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) have profound effects on plant growth and nitrogen (N) and phosphorus (P) nutrition. However, a comprehensive evaluation of how plant N and P respond to AMF inoculation is still unavailable. Here, we complied data from 187 original researches and carried out a meta-analysis to assess the effects of AMF inoculation on plant growth and N and P nutrition. We observe overall positive effects of AMF inoculation on plant performance. The mean increases of plant biomass, N concentration, P concentration, N and P uptake of whole plant are 47%, 16%, 27%, 67%, and 105%, respectively. AMF inoculation induces more increases in plant concentrations and storage of P than N. Plant responses to AMF inoculation are substantially higher with single AMF species than with mixed AMF species, in laboratory experiments than in field experiments, and in legumes than in non-legumes. The response ratios of plant N and P nutrition are positively correlated with AMF colonization rate, N addition, P addition, and water condition, while unvaried with experiment duration. The biggest and smallest effect sizes of AMF inoculation on plant performance are observed in the application of nitrate and ammonium, respectively. Accordingly, this meta-analysis study clearly suggests that AMF inoculation improves both plant N and P nutrients and systematically clarifies the variation patterns in AMF effects with various biotic and abiotic factors. These findings highlight the important role of AMF inoculation in enhancing plant N and P resource acquisitions and provide useful references for evaluating the AMF functions under the future global changes. [ABSTRACT FROM AUTHOR]

Introduction of non‐hexagons and/or heteroatoms allows for finely tuning the physicochemical properties of nanographenes. Heteroatoms doping have dominated the modulation of nanographenes with tunable band gap, rich electrochemical activities and so on. The pair of non‐hexagons, for instance, pentagon‐heptagon pairs, have furnished nanographenes with aromatic and/or antiaromatic characteristics, open‐shell properties and so on. In order to meet the growing demand for versatile nanographenes in materials science, research on novel nanographenes with heteroatom doped non‐hexagonal pairs has been aroused in recent years. In this review, we focus on nanographenes with nitrogen‐doped non‐hexagonal paris including the synthesis, structure analysis, photophysical properties, and potential applications in organic devices. [ABSTRACT FROM AUTHOR]

Fe has been doped into many systems to adsorb and activate nitrogen, and low-valence Fe was proposed to surpass the high-valence Fe in serving as an active site for the nitrogen reduction reaction. However, it is still unclear which properties and how the properties are affected by the charge on Fe. In order to unravel the mechanism and further provide support for experimental modifications, we obtain Fe with different charges on a base of Fe/g-C3N4, and found that the charge is not only determined by the surrounding atoms. With the aid of first-principles calculations, Fe with a low valence state is determined to be advantageous in increasing N2 adsorption stability, reducing the onset potential of the NRR and suppressing the competitive HER, which absorbs N2 in an end-on configuration and reduces it easily through distal mechanisms. Notably, it is not Fe, but FeN2 composed of Fe and two close N, which acts as a conduit to transfer electrons from the substrate to the intermediate product NxHy. In addition, the charge on FeN2 is a better descriptor than that on Fe to explain the interaction between Fe and N2 on it. Therefore, increasing the charge on Fe and FeN2 is a promising method to enhance nitrogen fixation activity. [ABSTRACT FROM AUTHOR]

The B, N co-doped carbon matrix loaded with ultra-small Ru nanoparticles (Ru/BNC) is an excellent bifunctional catalyst capable of efficiently catalyzing ammonia borane hydrolysis and alkaline water electrolysis for hydrogen evolution. [Display omitted] Developing a straightforward and general strategy to regulate the surface microenvironment of a carbon matrix enriched with N/B motifs for efficient atomic utilization and electronic state of metal sites in bifunctional hydrogen production via ammonia-borane hydrolysis (ABH) and water electrolysis is a persistent challenge. Herein, we present a simple, green, and universal approach to fabricate B/N co-doped porous carbons using ammonia-borane (AB) as a triple functional agent, eliminating the need for hazardous and explosive functional agents and complicated procedures. The pyrolysis of AB induces the regulation of the surface microenvironment of the carbon matrix, leading to the formation of abundant surface functional groups, defects, and pore structures. This regulation enhances the efficiency of atom utilization and the electronic state of the active component, resulting in improved bifunctional hydrogen evolution. Among the catalysts, B/N co-doped vulcan carbon (Ru/BNC) with 2.1 wt% Ru loading demonstrates the highest performance in catalytic hydrogen production from ABH, achieving an ultrahigh turnover frequency of 1854 min−1 (depending on the dispersion of Ru). Furthermore, this catalyst shows remarkable electrochemical activity for hydrogen evolution in alkaline water electrolysis with a low overpotential of 31 mV at 10 mA cm−2. The present study provides a simple, green, and universal method to regulate the surface microenvironment of various carbons with B/N modulators, thereby adjusting the atomic utilization and electronic state of active metals for enhanced bifunctional hydrogen evolution. [ABSTRACT FROM AUTHOR]

The structure and properties of polycrystalline chemical vapor deposition (CVD) diamond coatings grown by microwave plasma CVD in H2–CH4 mixtures can be effectively controlled by nitrogen admixture in the process gas. Here, a comparative study of adding nitrogen from different precursors, N2 and ammonia NH3, in concentrations up to 0.4%vol on grain size, texture, surface roughness, and sp2/sp3 ratio of the produced films on Si substrates is performed. A transition from microcrystalline to smooth nanocrystalline diamond structure is found to occur at a certain concentration of the precursor, for NH3 this threshold concentration being much lower, 0.02–0.1%, than for N2. The higher activity of ammonia is associated with easier formation of cyano radicals in the plasma as detected with optical emission spectroscopy, in accord with the lower bond‐dissociation energy for NH3 compared to N2. On the contrary, a smaller addition (0.004%) of either N2 or NH3 promotes almost doubling of the growth rate, while preserving the microcrystalline structure of the film. The results establish ammonia as a convenient alternative precursor to commonly used N2 added in the plasma for the diamond film structure modifications. [ABSTRACT FROM AUTHOR]

Research indicates that, owing to the enhanced grain-filling rate of tetraploid rice, its yield has notably improved compared to previous levels. Studies conducted on diploid rice have revealed that optimal planting density and fertilization rates play crucial roles in regulating rice yield. In this study, we investigated the effects of different nitrogen application and planting density treatments on the growth, development, yield, and nitrogen utilization in tetraploid (represented by T7, an indica–japonica conventional allotetraploid rice) and diploid rice (Fengliangyou-4, represented by FLY4, a two-line super hybrid rice used as a reference variety for the approval of super rice with a good grain yield performance). The results indicated that the highest grain-filling rate of T7 could reach 77.8% under field experimental conditions due to advancements in tetraploid rice breeding. This is a significant improvement compared with the rate seen in previous research. Under the same conditions, T7 exhibited a significantly lower grain yield than FLY4, which could be attributed to its lower grain-filling rate, spikelets per panicle, panicle number m−2, and harvest index score. Nitrogen application and planting density displayed little effect on the grain yield of both genotypes. A higher planting density significantly enhanced the leaf area index and biomass accumulation, but decreased the harvest index score. Compared with T7, FLY4 exhibited a significantly higher nitrogen use efficiency (NUEg), which was mainly due to the higher nitrogen content in the straw. Increasing nitrogen application significantly decreased NUEg due to its minimal effect on grain yield combined with its significant enhancement of nitrogen uptake. Our results suggest that the yield and grain-filling rate of T7 have been improved compared with those of previously tested polyploid rice, but are still lower than those of FLY4, and the yield of tetraploid rice can be further improved by enhancing the grain-filling rate, panicle number m−2, and spikelets per panicle via genotype improvement. [ABSTRACT FROM AUTHOR]

To study the characteristics and sources of nitrogen in the Baiyangdian Lake, this research conducted water quality monitoring during three hydrological periods (normal period, flood period, and dry period), and 165 pieces of routine water quality monitoring data were collected from the three national control sections for Baiyangdian Lake and its inflow rivers. By integrating water chemical analysis with multivariate statistical techniques, the study comprehensively investigated the spatiotemporal variation patterns of nitrogen in Baiyangdian Lake and identified the sources of nitrogen pollution. The results showed that the concentration of total nitrogen (TN) was highest during the dry period, reaching an average of 0.924 mg/L, and 31.3% of the sites exceeded the national Grade III surface water quality standard, reflecting a potential risk of nitrogen pollution. Based on the ion ratio method and principal component analysis (PCA), the main sources of nitrogen pollution in Baiyangdian Lake were identified as manure and domestic sewage, with agricultural fertilizers also having a certain impact on water nitrogen pollution. In addition, the study also compared the nitrogen concentration in Baiyangdian Lake with several important lakes in China. The results showed that the concentrations of TN and ammonium nitrogen (NH4+-N) in Baiyangdian Lake are lower than those in lakes in areas with similar human activity intensity, indicating that the water quality of Baiyangdian is relatively good. This study can provide a scientific basis for water quality management and pollution prevention for Baiyangdian Lake. [ABSTRACT FROM AUTHOR]

The productivity and quality of tomato crops are influenced by nutrient management and soil moisture levels. A study was conducted in Melkassa to find the best nitrogen fertilizer rate and soil moisture level for tomato crops. The experiment employed a split-plot design and was replicated three times. The combined impact of soil moisture and nitrogen levels greatly affects the height, branch count, fruit size, fruit length, marketable yield of tomatoes, tomato fruit quality, nitrogen use efficiency and water use efficiency (p <.05). The optimal combination of 75% ETc and 230 kg/ha resulted in the tallest tomato plant height and the highest branch number. The highest diameter and length of tomato fruits were obtained when 75% ETc and 184 kg/ha were combined. The highest marketable tomato yields were achieved by the interaction of 75% ETc and 184 kg/ha N. Applying 50% ETc with 184 and 138 kg/ha resulted in higher WUE. Interaction of 92 kg/h and soil moisture at all levels results in the maximum AUE. The maximum PFP obtained from 138 and 184 kg/ha with no significant difference. Excessive nitrogen rates (>184 kg/ha) did not increase tomato yield and WUE except for plant height and branch number. In general, the application of 75% ETc and 138 to 184 kg/ha of nitrogen is optimal for tomato production considering the measured parameter to improve water use efficiency and nutrient management in arid and semi-arid environment. The results gave valuable information and direction for the use of organic nitrogen and water in tomato production. [ABSTRACT FROM AUTHOR]

While state‐of‐the‐art organic photovoltaics (OPVs) have been achieved by halogen modification strategies for active layer materials, the stability of these OPVs can be compromised by the presence of halogen ions at the interface and within the photoactive layer. Herein, halogen‐free photoactive layer‐based OPV cells are fabricated and systematically studied to understand and explore the working principle and potential of this class of OPV devices. For the first time, a champion efficiency of 13.12% is achieved for the inverted device (ITO/AZO/AL/MoO3/Ag) based on the nonhalogenated photoactive layer PBDB‐T:BTP‐M. Superior metal electrode stability is confirmed for the unencapsulated PBDB‐T:BTP‐M devices aged at 85 °C in the air atmosphere compared to the halogenated PM6:Y6 devices. Specifically, better thermal stability is verified for the nonhalogenated device without 1‐chloronaphthalene (1‐CN) additive compared to the device with 1‐CN additive, with 89% of the initial efficiency retained after being aged for 900 h at 85 °C in the N2 atmosphere. These results evidence the halogen/halide impacts on device stability and demonstrate the potential for nonhalogenated OPVs to achieve efficient and stable performance, benefiting the development and practical application of this technology. [ABSTRACT FROM AUTHOR]

Nitrogen is critical for rice yield and quality, but its overuse can be detrimental to efficiency and the environment. To identify changes in the quality of rice in response to the reduced application of nitrogen fertilizer, we carried out a comprehensive metabolomics study of SuiJing 18 using volatile metabolomics methods. Our results showed that SuiJing 18 had a total of 358 volatile metabolites, mainly lipids (16.25%), terpenoids (15.41%), heterocyclic compounds (15.13%), and hydrocarbons (13.45%). SuiJing 18 underwent significant changes in response to the reduced application of nitrogen fertilizer. Key sweet volatile compounds such as 4-methyl-benzeneacetaldehyde, hexyl acetate, and 2-methylnaphthalene were present at significantly higher levels when nitrogen fertilizer was applied at a rate of 68 kg of pure nitrogen per hectare, and their flavor characteristics also differed significantly from the compounds resulting from the other two treatments. Focusing on 16 differential volatile metabolites, we further investigated their effects on flavor and quality, thus laying the foundation for a greater understanding of the biomarkers associated with changes in rice quality. This study contributes to a better understanding of the mechanisms underlying changes in rice quality after reduced nitrogen fertilizer application. [ABSTRACT FROM AUTHOR]

Lakeshore buffer zones serve as transitional areas between terrestrial and aquatic ecosystems, playing a crucial role in intercepting non-point source pollutants, purifying river and lake water, and maintaining ecological system dynamics. This study focuses on the vegetation of the lakeshore buffer zone in Songhua Lake, the largest artificial lake in Northeast China. The nitrogen (N) and phosphorus (P) pollutant contents and accumulation characteristics of herbaceous plants were investigated and analyzed in different regions and with different species. The study results indicate that there were no significant differences in N and P content, N: P ratio, and average accumulation among vegetation in the near-water, middle, and far lakeshores of the buffer area. The herbaceous plants with the highest N and P content and N: P ratios were Artemisia sieversiana, Sium suave, and Artemisia sieversiana, respectively. Purus frumentum planted in the middle lakeshore accumulated the highest amounts of N and P, reaching 87.97 g plant−1 and 3.86 g plant−1, respectively. The aboveground parts of plants showed significantly higher accumulation of N and P compared to the underground parts. The average enrichment coefficient for aboveground parts and underground parts for N were 4.83 and 4.35, respectively, all exceeding 1. However, their capability to enrich P was relatively weak, with only the aboveground parts of F − 3 showing some enrichment ability. Among herbaceous plants, Artemisia sieversiana and Sium suave exhibited the strongest capability for transporting N and P from underground to aboveground. Overall, harvesting aboveground biomass for the ecological removal of N and P in the study area appears feasible. Biomass is a critical factor influencing the nutrient interception capacity of vegetation, with Purus frumentum identified as an optimal restoration plant for sustainable management practices, and Artemisia sieversiana and Sium suave have the potential for rapid remediation. [ABSTRACT FROM AUTHOR]