Search Results (6,125)

Active screen plasma nitriding (ASPN) of additively manufactured nickel-based superalloys represents an understudied surface enhancement pathway. This study presents the first systematic investigation of ASPN applied to additively manufactured Inconel 939 (IN 939), evaluating four distinct post-processing routes combining heat treatment atmospheres (argon versus air cooling), vibratory finishing, and lapping under identical nitriding parameters (450 °C, 8 h, 25% N₂ + 75% H₂, 3 hPa). Contrasting nitriding behaviours emerged as a function of the post-processing route: the air-cooled thermal treatment (HT-air-vibr-lap) promotes formation of a thick Al/Cr-rich oxide layer (10–15 µm) that substantially inhibits nitrogen diffusion, resulting in thin and discontinuous nitrided layers. Conversely, the inert atmosphere route (HT-Ar-vibr-lap) circumvents oxide formation, enabling continuous S-phase (expanded austenite, γN) layer development of a 6.4 ± 0.3 µm thickness with exceptional surface hardness (~1200 HV, representing 3–4× enhancement relative to base material). X-ray diffraction confirmed S-phase formation with refined lattice parameter (3.609 Å) and secondary nitride phases (CrN-type and NbN/TaN-type precipitates). The post-processing sequence—particularly heat treatment atmosphere and mechanical finishing methodology—emerged as a critical controlling parameter for S-phase formation efficiency and mechanical properties of nitrided layers in additively manufactured nickel-based superalloys. This work addresses a knowledge gap distinct from the existing literature on conventional Inconel systems, establishing that controlled surface modification through post-processing can achieve the required properties. Full article

Using raw milk in cheesemaking poses several risks and often requires higher salt levels. Gel brine is a promising brining method to reduce salt and to prevent excessive softening, yet it was not employed to raw milk cheese before. In this study, the impact of ripening in gel brine—prepared by adding selected thickeners (gelatin and carrageenan) to a 12% salt brine—on the composition, proteolysis, texture, and microbiological properties of raw milk cheese was examined over 120 days. The aim was to assess the potential of gel brine to shorten the ripening time of raw milk cheese at a relatively low salt concentration while maintaining acceptable quality parameters. Response surface methodology was used to determine the optimum ripening time and thickener concentrations required to achieve target microbial counts, proteolysis, and moisture levels. The addition of stabilizers did not significantly influence the overall composition of the cheese, except for salt in dry matter. Stabilizers also limited the increase in trichloroacetic acid-soluble nitrogen (TCA-SN) during storage and led to a marked reduction in Escherichia coli counts. Texture profile analysis results were significantly affected (p < 0.05). The optimum conditions were estimated as 0.9% carrageenan, 0.8% gelatin, and 35 days of ripening. Full article

Spartina alterniflora, an invasive plant species in coastal regions of China, poses significant threats to local biodiversity and has become a pervasive weed in coastal wetlands and agricultural systems. With increasing nitrogen inputs in coastal areas, understanding the impact of nitrogen addition on plant–soil feedback dynamics in S. alterniflora is essential but remains poorly explored. This study aimed to investigate how nitrogen addition affects plant–soil feedback in S. alterniflora and its growth dynamics. We conducted a mesocosm experiment where nitrogen was added at different levels to assess its effects on the plant–soil feedback in S. alterniflora. The results showed that nitrogen addition significantly increased the aboveground biomass of S. alterniflora by approximately 38% to 88%, while decreasing its belowground biomass by about 22% to 41% Nitrogen addition weakened the negative plant–soil feedback, which typically limits the growth of S. alterniflora. This reduction in microbial resistance at higher nitrogen levels contributed to enhanced overall growth of the plant. These findings highlight the critical role of nitrogen inputs in facilitating the growth of invasive S. alterniflora and suggest that excessive nitrogen in coastal ecosystems could accelerate the spread of this invasive species. Future research should focus on exploring strategies to regulate nitrogen levels in coastal wetlands and agricultural systems to mitigate the ecological impact of invasive species. Full article

In this study, the changes in the DNA native conformation induced by pH changes in the alkaline and acidic regions were examined. It was shown by the methods of low gradient viscometry and flow birefringence that protonation and deprotonation of nitrogen bases inside the double helix cause a change in the persistent length of DNA. The pK values shift with the change in the ionic strength of the solution (NaCl concentration). The additional charges appearing on the DNA bases are not shielded by counterions from the solution. The increase and decrease in the volume of the DNA coil in solution resulting from protonation and deprotonation of base pairs, respectively, are mainly determined by changes in the persistent length of the macromolecule. The stability of the double-helical conformation of DNA ensures the steadiness of the equilibrium rigidity of this macromolecule. The emergence of charges on the bases, resulting from DNA protonation or deprotonation, weakens and even disrupts the hydrogen bonds between complementary bases. However, at the first stage, this occurs without altering the stacking interactions of base pairs, as reflected in the absorption spectra of DNA and in the stability of the DNA persistent length at different pH levels. Full article

There are large amounts of carbohydrates and proteins in rban perishable organic waste (UPOW), which can be converted to short chain fatty acids (SCFAs) through microbial methods. In this study, the mass balance and properties of organic slurry generated from UPOW pretreatment were investigated first. Then, the optimal conditions for SCFAs production from organic slurry of UPOW was studied. It was found that under the conditions of pH 8 ± 0.5 and reaction time of 3 d, the yield of SCFAs, mainly composed of acetic and propionic acids, in the full-scale reactor was 0.68 gCOD/gTCOD of organic slurry. Under the conditions of influent NH₄⁺-N, total nitrogen, soluble ortho-phosphorus, and soluble COD of 27–39, 33–45, 2–9, and 220–300 mg/L, respectively, the use of SCFAs-enriched fermentation liquid (100 mg COD/L) as the additional carbon source for full-scale biological municipal wastewater treatment showed a higher total nitrogen and phosphorus removal efficiency than that of sodium acetate (88.1 ± 5.2% against 81.4 ± 4.5% and 96.9 ± 3.1% versus 91.5 ± 2.8%) due to greater key enzyme activity and short-cut nitrification and denitrification capacity. Finally, based on the actual operation process, an economic benefit analysis on the production of SCFAs-enriched fermentation liquid from UPOW was conducted, and the issues that need to be addressed for the promotion and application of this technology were discussed. This study contributes to achieving sustainable synergistic treatment of organic waste and wastewater. Full article

Volvariella volvacea were grown on an abandoned cotton-based substrate, which was divided into two conditions: a group with added nutrients (N3P3) and a control group (CK). Using metagenomic sequencing technology, the study investigated the effect of nutrient addition during the growth process of V. volvacea on the microbial community and metabolic pathways of the substrate. The study found that the main bacteria in the N3P3 group were Proteus and Microsporidium, while in the CK group, Bacillus marinosus and Microsporidium globosa were more common. At all stages of V. volvacea growth, Proteobacteria and Firmicutes dominated. Metabolic function analysis showed that the N3P3 group significantly increased amino acid metabolism, nitrogen metabolism, genetic information processing, and cellular processes, while reducing the contents of pathogenic and saprophytic symbiotic fungi. Nitrogen metabolism, phosphorus metabolism, and carbon metabolism were closely related to the growth of V. volvacea, and nutrient addition significantly improved microbial community diversity and metabolic levels, which can be used as a substrate optimization formula. This is of great significance for the development of sustainable agriculture. Full article

Accurate crop yield estimation under differentiated management practices is a core requirement for the development of smart agriculture. However, current yield estimation models face two major challenges: limited adaptability to different management practices, thus exhibiting poor generalizability, and ineffective integration of multi-source remote sensing features, limiting further improvements in estimation accuracy. To address these issues, this study integrated UAV-based multispectral and thermal infrared remote sensing data to propose a yield estimation framework based on multi-source feature fusion. First, three machine learning algorithms—Partial Least Squares Regression (PLSR), Random Forest (RF), and Extreme Gradient Boosting (XGBoost)—were employed to retrieve key biochemical parameters of winter wheat. The RF model demonstrated superior performance, with retrieval accuracies for chlorophyll, nitrogen, and phosphorus contents of R² = 0.8347, 0.5914, and 0.9364 and RMSE = 0.2622, 0.4127, and 0.0236, respectively. Subsequently, yield estimation models were constructed by integrating the retrieved biochemical parameters with phenotypic traits such as plant height and biomass. The RF model again exhibited superior performance (R² = 0.66, RMSE = 867.28 kg/ha). SHapley Additive exPlanations (SHAP) analysis identified May chlorophyll content (Chl-5) and March chlorophyll content (Chl-3) as the most critical variables for yield prediction, with stable positive contributions to yield when their values exceeded 2.80 mg/g and 2.50 mg/g, respectively. The quantitative assessment of management practices revealed that the straw return + 50% inorganic fertilizer + 50% organic fertilizer (RIO50) treatment under the combined organic–inorganic fertilization regime achieved the highest measured grain yield (11,469 kg/ha). Consequently, this treatment can be regarded as an optimized practice for attaining high yield. This study confirms that focusing on chlorophyll dynamics during key physiological stages is an effective approach for enhancing yield estimation accuracy under varied management practices, providing a technical basis for precise field management. Full article

Background: Flavin cofactors, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), are indispensable for plant metabolism, supporting photosynthesis, photorespiration, mitochondrial electron transport, nitrogen assimilation, and cellular redox balance. Both cofactors derive from riboflavin (vitamin B₂), which plants synthesize de novo, unlike animals, which rely on dietary intake. While the riboflavin biosynthesis pathway has been biochemically well-characterized, its transcriptional regulation and cellular organization remain poorly understood. Methods: Here, using large-scale transcriptomic datasets as well as co-expression and cis-element analyses, we systematically investigated the expression dynamics of riboflavin metabolism genes in Arabidopsis thaliana. In addition, HPLC was employed to monitor flavin level fluctuations in plants under abiotic stresses. Results: Most genes displayed strong expression in photosynthetic and reproductive tissues, consistent with elevated metabolic demands for flavins in redox reactions and energy metabolism. Under osmotic stress, RIBA1, RIBA3, PYRD, PYRR, COS1/LS, and RS, genes encoding enzymes involved in the early and intermediate steps of riboflavin biosynthesis were transcriptionally downregulated. In contrast, RIBA2, FHY1/PYRP1 and FMN/FHY were upregulated, whereas FADS1 and NUDX23, genes encoding enzymes responsible for interconversion between FMN and FAD, were suppressed. Gene expression responses are consistent with the maintenance of flavin homeostasis, affecting flavin level changes under abiotic stress. Conclusions: This study establishes a comprehensive framework for the transcriptional regulation of flavin biosynthesis in plants. The findings reveal stress-responsive reprogramming of flavin metabolism and identify promising strategies for engineering crops for biofortification, metabolic efficiency, and stress resilience. Full article

Forest fine root litter enters agricultural soils in some cases and its decomposition would change the soil’s properties. However, how this process further influences the ammonia (NH₃) volatilization and nitrous oxide (N₂O) emission from agricultural soil receiving fertilizer nitrogen (N) is unknown. Here, we conducted a soil pot experiment to investigate the responses of the aforementioned gaseous N losses during wheat season to fine root litters derived from Populus deltoides (RP) and Metasequoia glyptostroboides (RM) incorporations. The results showed that two forest fine root litters reduced total NH₃ losses by 30.6−31.9% from 180 kg N ha⁻¹ applied to farmland soil, and this effect was attributed to decreased soil urease activity and ammonium-N during the basal N fertilization period. Whether receiving fertilizer N or not, N₂O emissions from farmland soil were significantly (p < 0.05) mitigated by 62.8–68.2% and 43.0−50.0% following the RP and RM incorporation, respectively. Lower N₂O emission was ascribed to increased soil pH but decreased soil nitrate-N and bulk density. In addition, less AOA and AOB amoA but more nosZ gene abundances explained the fine root litter-induced N₂O mitigation effect. Neither forest fine root litter exerted a negative effect on wheat grain yield and crop N use efficiency in N-added agriculture soil. In conclusion, forest fine root litter incorporation could help to mitigate gaseous N losses via NH₃ volatilization and N₂O emission from fertilizer-N-applied agricultural soils, and without crop production loss. Full article

Potato (Solanum tuberosum) is one of the world’s most important food crops, with tuber sink strength and starch deposition determining yield, quality, and processing performance. While starch is the dominant carbohydrate reserve, its accumulation is tightly linked with protein metabolism. Patatin, the major soluble storage protein, constitutes up to 40% of total tuber protein. In addition to serving as a nitrogen and carbon reserve, patatin exhibits lipid acyl hydrolase (phospholipase A₂-like) activity, suggesting roles in membrane remodeling and stress signaling. This dual identity places patatin at the intersection of storage, metabolic regulation, and defense. A structured review of studies published between 1980 and 2025 was developed using PubMed, Web of Science, Frontiers, and MDPI databases. Prioritized research included molecular, physiological, and multi-omics analyses of patatin expression, regulation, and function under optimal and stress conditions. Evidence indicates that patatin contributes to carbon–nitrogen balance and sink strength by affecting sucrose import, vacuolar osmotic capacity, and starch biosynthesis. Under drought, salinity, and pathogen stress, patatin transcript levels, protein stability, and enzymatic activity shift, leading to reduced starch deposition, altered sugar accumulation, osmoprotection, and reallocation toward defense responses. Despite these insights, major knowledge gaps remain. These include isoform-specific roles, integration into sugar–hormone regulatory networks, and field-scale responses under fluctuating environments. Future progress will require integrated multi-omics, fluxomics, and proximity-labeling approaches, combined with CRISPR-based isoform editing and promoter engineering. Targeting patatin as both a biomarker and an engineering node offers opportunities to develop climate-ready potato cultivars with improved starch yield, tuber quality, and stress resilience. Full article

Intermetallic alloys based on A15-type compounds, including cubic Ti₃Sb, attract increasing interest due to their tunable electronic properties and potential for surface-related functional applications. Here, the interaction of nitrogen with Ti₃Sb is systematically investigated using spin-polarized density functional theory within the GGA-PBE approximation. Nitrogen adsorption was analyzed on the Ti₃Sb (111), (100), and (110) surfaces by considering top, bridge, and hollow sites at different surface coverages. Low nitrogen coverage was found to minimize lateral adsorbate interactions, allowing reliable evaluation of single-atom adsorption energies. Among the studied configurations, nitrogen adsorption at the hollow site of the Ti₃Sb (111) surface is energetically most favorable. In addition, partial substitution of Ti or Sb atoms by nitrogen in Ti₃Sb supercells was examined to assess its effect on bulk electronic properties. Nitrogen incorporation leads to pronounced modifications of the electronic band structure, density of states, and local magnetic moments, with a strong dependence on crystallographic direction. The calculated results reveal distinct electronic anisotropies originating from direction-dependent band dispersion and associated effective carrier masses. These findings clarify the role of nitrogen in tailoring both surface and bulk electronic characteristics of Ti₃Sb and provide a theoretical basis for the targeted design of A15-type intermetallic materials for sensing, catalytic, and energy-related applications. Full article

β-alanine has been shown to significantly improve nitrogen utilization efficiency in beef cattle, but its impact on growth performance remains unclear. This study involved 36 healthy 18-month-old Simmental crossbred bulls with similar weights (627 ± 41 kg). The cattle were divided into two groups, with each group comprising six replicates of three animals. While the control group received the basal diet, the treatment group was administered an additional 96 g/d/cattle rumen-protected β-alanine (RP-β-Ala). The study was conducted over a 35-day period, which included an initial 7 days for adaptation. At the end of the trial, body weight was recorded, and samples were collected. Results show that RP-β-Ala enhanced average daily gain (p = 0.065) and crude protein (CP) digestibility (p = 0.065) and reduced gain-to-feed ratio (p = 0.078). Analysis of rumen microbiota revealed that RP-β-Ala positively modulated the rumen microbiota by enriching beneficial genera such as Prevotella, Treponema, and Selenomonas. This enrichment increased volatile fatty acid production and nitrogen utilization efficiency, as evidenced by elevated ruminal ammonia-N and microbial CP levels, along with decreased serum urea nitrogen. Metabolomics identified key alterations in arachidonic acid metabolism, specifically the upregulation of metabolites 14,15-DiHETrE and prostaglandin D2, and enhanced antioxidative capability indicated by increased serum total antioxidant capacity (T-AOC). Concurrently, RP-β-Ala reduced serum TNF-α levels. This reduction was achieved by suppressing harmful bacteria like Thermoactinomyces and Saccharopolyspora, along with inhibiting their polyamine synthesis, specifically spermine and spermidine. Collectively, these effects alleviated oxidative stress and inflammation. These findings demonstrate that RP-β-Ala enhances beef cattle growth through improved energy supply and antioxidant capacity. Full article

Background/Objectives: Coleus aromaticus (Lamiaceae), also known as Cuban oregano or Indian borage, is a semi-succulent perennial species widely used in traditional medicine for its therapeutic and nutritional properties. While its essential oils and aromatic fraction have been extensively investigated, the characterization of its non-volatile metabolites remains limited. The aim of this study was to explore the chemical composition of fresh leaves with a focus on the non-volatile fraction. Methods: Fresh leaves of C. aromaticus were cryogenically treated with liquid nitrogen, ground, and subjected to three different extraction procedures: hydroalcoholic maceration, ethyl acetate maceration, and liquid–liquid partitioning to obtain a dichloromethane organic phase and a hydroalcoholic phase. Extracts and fractions were analyzed by HPTLC and HPLC for metabolic profiling. In addition, the Bligh–Dyer method was applied to separate polar and non-polar metabolites, which were subsequently characterized using NMR spectroscopy. Results: Chromatographic analyses highlighted the occurrence and distribution of organic acids, polyphenols (notably flavonoids), and proteinogenic amino acids. Spectroscopic data confirmed the presence of diverse polar and non-polar metabolites, providing a more detailed chemical fingerprint of C. aromaticus. This integrated approach broadened the phytochemical profile of the species beyond the well-documented essential oils. Conclusions: The results contribute to a better understanding of the non-volatile metabolites of C. aromaticus, offering novel insights into its chemical diversity. These findings highlight the potential of this plant as a valuable source of bioactive compounds, supporting its future application in nutraceutical and pharmaceutical research. Full article

Urbanization, expanding tourism, and infrastructure development are altering water quality in the Yucatán Peninsula (YP). This study evaluated temporal variations in water quality and trophic status using the Water Quality Index (WQI) and Trophic State Index (TSI) across ten inland water systems (IWS) monitored from 2012 to 2024. Spatial patterns from an additional 29 IWS sampled in 2024 were also analyzed. The Mann–Kendall test and Theil–Sen estimator revealed a significant decline in water quality (Z = −9.07, β = −2.62) and a sustained increase in eutrophication (Z = 4.00, β = 1.15). The NMDS separated two lake groups: one with high nutrients and total coliforms, and another with elevated TDS and conductivity. The PCA identified turbidity, nitrogen, chlorophyll-a, and total coliforms as variables exerting the strongest influence on water variability. The WQI indicated generally poor conditions except in Bacalar Centro and Xul-Ha, which showed fair quality. The highest TSI values occurred in inland systems, except for La Sabana, which exhibited hypereutrophic conditions linked to wastewater inputs. NT–PT ratio indicated nitrogen limitation in most lakes, likely driven by groundwater recharge and low surface runoff. Overall, results demonstrate a progressive decline in water quality and widespread eutrophication across the YP. Full article

The rapid urban expansion in the past few decades has resulted in a deficit of urban green space, and green roofs have become an effective way to expand urban green spaces. High nitrogen (N) deposition induced by urban development has threatened the health and sustainability of plants. The aim of this study was to evaluate the responses of plant growth performance and aesthetic value to N deposition in green roofs. Eleven species from four plant functional groups were grown under control, low N addition, and high N addition conditions to assess the effects of N addition on their growth performance, aesthetic value, soil properties, and plant functional traits. Different plant functional groups exhibited distinct traits, and their response to N addition was different. Under high N addition, the growth performance of sod-forming graminoids and tall forbs decreased by 47.0% and 23.7%, and their aesthetic value decreased by 24.4% and 16.2%, respectively. Growth performance of plant functional groups was mainly determined by plant functional traits rather than soil properties. The poor growth performance and aesthetic value of sod-forming graminoids and tall forbs challenged their widespread use under high N addition. This study highlighted the importance of selecting environmentally adaptive species from the perspective of plant functional groups, especially in the context of future high N deposition. Full article