Search Results (158)

Soil erosion, structural degradation, and inefficient nitrogen (N) use jointly constrain dryland agriculture on the Loess Plateau—a globally recognized ecologically fragile region. A common concern is that soil conservation practices may reduce short-term crop productivity. This study evaluated whether conservation tillage based on no-tillage and straw mulching, particularly when coupled with controlled-release N, could enhance soil aggregate stability, apparent nutrient availability, soybean productivity, and N-use efficiency. A two-year field experiment was conducted in 2022–2023 at the Shenmu Erosion and Environment Research Station, Shaanxi Province, China. Five treatments were compared: conventional tillage without N application (CTCK), conventional tillage with normal N application (CTU), conservation tillage without N application (SMCK), conservation tillage with normal N application (SMU), and conservation tillage with controlled-release N (SMS). SMS consistently increased the proportion of >0.25 mm water-stable macroaggregates, mean weight diameter, and geometric mean diameter. It also increased soil organic carbon and its particulate and mineral-associated fractions in the 0–30 cm profile, improved total N, mineral N, total P, and available P, and produced the highest soybean yield. Across two years, SMS yielded 1960.57 kg ha⁻¹, 162.26% higher than CTCK and 66.66% higher than CTU. The treatment also achieved the highest agronomic efficiency despite reduced N input. These findings indicate that integrating conservation tillage with controlled-release N can enhance soil structural stability, apparent nutrient availability, and soybean productivity. It confirms that soil conservation and high crop output are mutually reinforcing rather than conflicting. Given the ecological sensitivity of the Loess Plateau, this integrated strategy offers a promising pathway toward more resilient dryland farming systems. Full article

In silicone polymers, more than 90% of the main chain skeletons are linked by Si-O-Si bonds, with organic groups attached to the side chains and terminal groups. These polymers possess both organic and inorganic properties, exhibiting excellent resistance to high and low temperatures, good insulation, and weather resistance. They are widely used in aerospace, biomedical, electrical, transportation sectors and so on. Traditional methods for synthesizing silicones, such as carbon thermal reduction, have led to a sharp increase in global CO₂ emissions. Consequently, developing technologies for the efficient degradation and recycling of small siloxane molecules from waste silicone polymers has become a research hotspot in the silicone industry. This paper explores the technical selection and research progress of physical recycling methods such as mechanical grinding, ultrasonication, and irradiation, as well as chemical recycling methods including pyrolysis and acid–base catalysis, in the field of silicone recycling. This holds significant practical implications for achieving a closed-loop cycle for silicones and reducing carbon emissions in the industry. Full article

The Qinghai–Tibet Plateau, a globally significant ecological barrier and a core pastoral region, is persistently constrained by cold and arid climatic conditions, nutrient poor soils, and progressive grassland degradation. These challenges necessitate maintaining forage productivity while enhancing ecological stability. Medicago sativa L., valued for its high nutritional quality and capacity for biological nitrogen fixation, has been widely incorporated into regional grassland systems. Rhizobial inoculation, as an environmentally sustainable agronomic practice, is regarded as an effective approach to improving nutrient use efficiency and promoting ecological restoration; however, its underlying mechanisms in cold and arid environments remain insufficiently understood. This study established a field experiment in Delingha, Qaidam Basin, using the cultivar ‘Beilin 201’. Treatments included an uninoculated control (CK) and four rhizobial seed coating rates: E1 (0.75 g·m⁻²), E2 (1.50 g·m⁻²), E3 (2.24 g·m⁻²), and E4 (3.00 g·m⁻²). The effects on yield, rhizosphere soil physicochemical properties, bacterial community structure, and molecular ecological networks were systematically evaluated. The composite microbial inoculant maintained Medicago sativa L. yield, with only modest and non-significant increases in some treatments. In contrast, soil organic matter increased significantly with application rate (p < 0.001), suggesting a stronger short-term effect on soil properties than on yield. Although network vulnerability was lowest in E4, the differences among treatments were not statistically significant. Mixed effects modeling showed that soil factors (74.79%) and microbial factors (25.12%) jointly influenced yield variation. Structural equation modeling further revealed that microbial factors exerted a positive direct effect on yield (0.3), whereas soil factors exhibited a stronger direct effect (0.57), with inoculation rate primarily influencing yield indirectly through soil mediated pathways. This study elucidates the ecological functions and regulatory mechanisms of rhizobial formulations in high elevation dryland ecosystems and provides both theoretical support and practical guidance for the rational application of microbial fertilizers and the sustainable management of forage systems on the Qinghai–Tibet Plateau. Full article

The DNA methylation landscape in the lungs of argali hybrid sheep infected with Mycoplasma ovipneumoniae (Mo) remains poorly characterized. This study aimed to profile genome-wide DNA methylation using reduced representation bisulfite sequencing (RRBS) and to validate key genes using bisulfite sequencing PCR (BSP), methylation-specific PCR (MSP), and quantitative MSP (QMSP). The results revealed a significant increase in global mCG methylation in -infected lungs. RRBS identified 3691 differentially methylated regions (DMRs), 66.2% of which were hypermethylated. Methylation levels were highest in gene bodies/downstream regions and lowest in promoters/5′ untranslated regions. Differentially methylated genes (DMGs) were enriched in immune–inflammatory pathways (e.g., antigen presentation, B-cell receptor signaling, Th17 differentiation) and, to a lesser extent, neural signaling pathways. BSP confirmed the methylation status of hypermethylated (KHDC3L, GILT, OVAR-DRB1, SGK1, ADAM17) and hypomethylated (EFCAB11, AP1B1, TATDN1) DMGs. Independent validation by MSP and QMSP further supported the hypermethylation of SGK1 and GILT in both lung tissue and alveolar macrophages. Quantitative reverse-transcription PCR showed that promoter hypermethylation of KHDC3L, GILT, SGK1, and ADAM17 was associated with transcriptional downregulation, while hypomethylation of AP1B1 correlated with upregulation. In summary, Mo infection induces genome-wide hypermethylation reprogramming that dysregulates key immune-related genes, highlighting potential epigenetic mechanisms in the pathogenesis of mycoplasmal pneumonia. Full article

To address the high energy consumption and low efficiency in shredding film–stalk mixtures during the resource utilization of cotton-field residues in Xinjiang—issues arising from the large mechanical-property differences among the mixture components—a custom single-support shearing fixture was developed to investigate the effects of residual-film wrapping layers, blade rake angle, sliding-cutting angle, and shearing speed on the F_j^max. Based on a Box–Behnken response surface design combined with analysis of variance and microscopic observations of the shearing process, the results showed that all main-effect factors had extremely significant influences on the F_j^max (p < 0.0001). Their relative contributions followed the following order: number of film wrapping layers > blade rake angle > shearing speed > sliding-cutting angle. Residual-film wrapping markedly increased shear resistance; increasing the sliding-cutting angle effectively reduced the shearing force; and reducing the rake angle facilitated more energy-efficient shredding. Interaction analysis further revealed significant coupling between sliding-cutting angle and shearing speed, rake angle and sliding-cutting angle, and rake angle and shearing speed (p < 0.05). Comparative shearing tests indicated that pure cotton stalks exhibited continuous brittle fracture with relatively stable force–displacement profiles, whereas film–stalk composites showed a sequentially coupled failure mode characterized by “residual-film pre-shearing–primary stalk fracture–secondary film stretching,” leading to multi-peak fluctuations in the force–displacement curves. Based on response surface optimization and mechanistic analysis, a parameter combination of a 35° rake angle, a 4–8° sliding-cutting angle, and medium-to-low shearing speed is recommended for shredding operations. This study elucidates the shearing and fragmentation mechanisms of film–stalk mixtures, provides theoretical guidance for optimizing key structural and operational parameters of post-recovery equipment, and offers important engineering value for promoting farmland residual-film pollution control and agricultural waste resource utilization. Full article

Monitoring the freshness of Salmo salar within cold chain logistics is paramount for ensuring food safety. However, conventional physicochemical and microbiological assays are impeded by inherent limitations, including destructiveness and significant time latency, rendering them inadequate for the real-time, non-invasive inspection demands of modern industry. Here, we present a novel detection framework synergizing hyperspectral imaging (400–1000 nm) with the Transformer deep learning architecture. Through a rigorous comparative analysis of twelve preprocessing protocols and four feature wavelength selection algorithms (Lasso, Genetic Algorithm, Successive Projections Algorithm, and Random Frog), prediction models for Total Volatile Basic Nitrogen (TVB-N) and Total Viable Count (TVC) were established. Furthermore, the capacity of the Transformer to capture long-range spectral dependencies was systematically investigated. Experimental results demonstrate that the model integrating Savitzky-Golay (SG) smoothing with the Transformer yielded optimal performance across the full spectrum, achieving determination coefficients (R²) of 0.9716 and 0.9721 for the Prediction Sets of TVB-N and TVC, respectively. Following the extraction of 30 characteristic wavelengths via the Successive Projections Algorithm (SPA), the streamlined model retained exceptional predictive precision (R² ≥ 0.95) while enhancing computational efficiency by a factor of approximately six. This study validates the superiority of attention-mechanism-based deep learning algorithms in hyperspectral data analysis. These findings provide a theoretical foundation and technical underpinning for the development of cost-effective, high-efficiency portable multispectral sensors, thereby facilitating the intelligent transformation of the aquatic product supply chain. Full article

This study expands research on Cinchona calisaya, which has traditionally focused on alkaloids, to address the insufficient comprehensive utilization of its resources. It is the first to explore the feasibility of extracting phenolic compounds from Cinchona calisaya using subcritical water extraction (SCWE) technology. Combining single-factor experiments with Box–Behnken design-response surface methodology (BBD-RSM), the study optimized three key process parameters, namely extraction temperature, extraction time, and liquid-to-solid ratio, with total phenolic content (TPC) as the response variable. Optimal extraction conditions were 165 °C, 20 min, and a liquid-to-solid ratio of 70:1 mL/g. Under these conditions, the TPC values were 98.41 ± 1.06 mg/g for bark and 37.96 ± 1.18 mg/g for heartwood, significantly higher than those obtained by traditional hot water extraction (THWE). Ultra-high performance liquid chromatography-Q-orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) identified 1198 and 1156 metabolites in the bark and heartwood, respectively, with a higher content of phenolic compounds in the heartwood. The extracts showed strong inhibitory activity against Staphylococcus aureus, weak inhibitory activity against Escherichia coli at high concentrations, and no inhibitory effect on Candida albicans. This study provides a theoretical basis and technical support for the comprehensive utilization of Cinchona calisaya resources and the green development of natural antioxidants and antimicrobial agents. Full article

To enable mains-free wireless access in confined environments such as tunnels and mines, this paper proposes and experimentally demonstrates a converged power-over-fiber (PoF) and analog radio-over-fiber (A-RoF) system over a single standard single-mode fiber (SMF). Using wavelength-division multiplexing (WDM), the system employs 1310 nm/1330 nm channels for bidirectional RF transmission and a 1550 nm channel for optical power delivery, respectively, while an ultra-simplified remote unit (RU) with a steady-state power consumption of 0.37 W is designed to match the PoF power-delivery capability. Experimental results show that for back-to-back, 1 km and 2 km links, the A-RoF performance remains essentially unaffected, with error vector magnitude (EVM) remaining stable, as the delivered PoF optical power varies from 0 to 3 W. For the 2 km transmission case, an incident PoF optical power of 2 W at the photovoltaic power converter (PPC) is sufficient to sustain stable system operation for over 10 hours. Under these conditions, using an IEEE 802.11ax MCS-7 (64QAM ) waveform, the optimum operating point yields an EVM of approximately 0.7%, satisfying the MCS-7 modulation-quality requirement. Full article

Sloping cropland on the Loess Plateau faces severe challenges from soil organic carbon (SOC) depletion and structural instability due to erosion and intensive tillage. Although mulching can enhance SOC sequestration, its long-term effects on the spatial distribution of SOC and aggregates across slopes remain unclear. A 15-year field experiment evaluated five practices—conventional tillage (T), no tillage (NT), straw mulching (SM), plastic film mulching (PM), and ridge–furrow plastic film mulching (RPM)—on SOC storage, aggregate stability, and their variation with different slope positions. Compared to T, all mulching treatments significantly increased SOC concentration by 4.19% to 83.48% in the 0–30 cm layer. SM and RPM notably increased macro-aggregates (>2 mm) and their associated SOC (24.04–56.49% higher than T) by adding organic matter and optimizing micro-topography. Different slope positions strongly influenced SOC redistribution: lower slopes accumulated more SOC than upper slopes due to erosion–deposition processes. Mulching reduced SOC spatial variability and minimized differences between slope positions. Although mulching increased cumulative SOC mineralization compared to T, the long-term net SOC gain was positive, driven by improved aggregate protection and reduced erosion. SM and RPM are recommended for sustainable slope farmland management due to their dual benefits in enhancing carbon sinks and soil stability. This study offers practical strategies for improving soil health and SOC sequestration in vulnerable sloping landscapes. Full article

Soil total carbon (TC) and total nitrogen (TN) are key indicators of soil fertility and ecosystem stability, particularly in dryland agroecosystems. However, how rotational tillage combined with straw return affects aggregate formation and aggregate-associated TC and TN stabilization remains insufficiently understood. In this study, we aimed to clarify how rotational tillage affects aggregate structure, stability, and the spatial distribution of TC and TN, thereby revealing internal processes driving nutrient stabilization in dryland farming systems. A long-term field experiment was conducted at the Shenfeng site of Shanxi Agricultural University, China, including three rotational tillage systems with straw return: T1 (two years of no tillage (NT) + one year of deep tillage (DT)), T2 (two years of conventional tillage (CT) + one year of DT), and T3 (two years of DT + one year of CT). Soil aggregates were separated into total mechanical aggregate (TMA), 0.25–2 mm MA, and 2–10 mm MA, and they were further fractionated into water-stable aggregates (WM, Wm, and Wf) for TC and TN analysis. The results showed that aggregate stability, TC, and TN were positively correlated and decreased with soil depth, indicating strong surface enrichment. TC was mainly enriched in 0.25–2 mm MA, whereas TN was concentrated in 2–10 mm MA, and water-stable macroaggregates (WM) acted as the dominant reservoirs for R_C and R_N. Relative to the 2016 baseline (CK), TC in 2022 tended to be higher under rotational tillage with straw return, while NT-containing systems better maintained TN across the 0–60 cm profile. Among the treatments, T1 provided the most balanced performance, with a higher MWD and GMD, lower D, and improved aggregate-associated TC and TN retention. These findings suggest that rotational tillage with straw return, particularly the NT–NT–DT sequence, can support aggregate stability and is associated with improved aggregate-mediated TC and TN retention in the Loess Plateau dryland winter wheat system. Full article

The rising price of sika deer meat is increasing the risk of economic adulteration, highlighting the need for rapid and reliable authentication methods to protect both market integrity and consumers. This work presents a novel countermeasure: a polymerase chain reaction (PCR)-based nucleic acid test strip designed for the specific and visual identification of sika deer meat. Our approach commenced with the design of specific primers targeting the cytochrome C oxidase subunit I (COI) gene. To guarantee the reliability of the assay, a DNA standard plasmid was constructed to serve as an unambiguous positive control for the PCR. Under optimized conditions, results showed that authentic sika deer meat generated both test and control lines on the strip, while adulterated and negative samples produced only the control line. The assay demonstrated flawless specificity and a detection sensitivity of 1.0 ng·μL⁻¹ for target DNA, representing a tenfold enhancement over gel electrophoresis. Furthermore, the method demonstrated a detection limit of 1% for sika deer meat in admixed samples, with a faint but visible signal observed down to 0.1% under optimized conditions. In conclusion, the developed test strip method is not only specific and sensitive but also user-friendly, positioning it as a practical and powerful tool for rapid, on-site meat authentication. Full article

The Songhua River Basin (SRB) in Northeast China is a high-latitude basin experiencing significant snow cover changes under global warming. This study quantified spatiotemporal changes in snowmelt in the SRB (1961–2020). A specific focus was placed on the changes at event scale, including frequency, magnitude and duration, that have been underexplored in previous work. Correlations between snowmelt and key driving factors were assessed to identify the dominant controls governing the melt process. A significant elevation-dependent decreasing trend in annual snowmelt was found over the decades, with the decrease most pronounced at lower elevations. Relative to the baseline period (1961–1990), the snowmelt dates during 1991–2020 advanced, with the 25%, 50%, and 75% cumulative levels occurring 9, 6, and 2 days earlier, respectively. Seasonally, snowmelt increased significantly in early spring (February to March) but decreased notably in late spring (April to May). Snowmelt events exhibited reduced frequency, total volume, peak value, and mean rate, along with fewer extreme events. The strongest correlation across snowmelt event types was found with mean snow depth for complete depletion and with accumulated sunshine duration for incomplete depletion, while Rain-on-Snow Melt events were most closely associated with sunshine and temperature. This study can provide a crucial reference for sustainable water management and spring agricultural irrigation in the SRB. Full article

Global Navigation Satellite System (GNSS)/Inertial Navigation System (INS) integrated navigation is one of the key methods for achieving precise positioning in complex urban environments. However, in some scenarios such as urban canyons, overpasses, and foliage occlusion, GNSS signals are frequently attenuated or interrupted, leading to degraded positioning accuracy when relying solely on INSs. To address this limitation, this study developed an improved GNSS/INS-integrated navigation algorithm based on a hybrid framework that combines a Robust Adaptive Kalman Filter (RAKF) with a Radial Basis Function (RBF) neural network. The RAKF allows a multi-criterion optimization strategy to be created to adaptively adjust the measurement noise covariance matrix according to GNSS data quality indicators such as PDOP, the number of satellites, and signal quality factors. This enhances the filter’s robustness and outlier detection capability under degraded GNSS conditions. Meanwhile, the RBF network is trained to predict pseudo-position increments, which substitute missing GNSS measurements during signal outages to maintain continuous navigation. Real-world vehicular experiments were conducted to evaluate the proposed RBF-aided RAKF (RBF-RAKF) against three other methods: the Extended Kalman Filter (EKF), standard RAKF, and RBF-aided Kalman Filter (RBF-KF). The experimental results demonstrate that during GNSS outages the proposed method achieved root mean square (RMS) positioning errors of 0.94, 1.02, and 0.21 m in the north, east, and down directions, respectively, representing improvements of over 90% compared with conventional filters. Moreover, the algorithm maintained meter-level horizontal accuracy and sub-meter vertical precision under severe GNSS signal degradation. These results confirm that the proposed RBF-RAKF algorithm provides stable and high-precision navigation performance in challenging urban environments. Full article

The separation of walnut kernels from shells is a crucial step in walnut processing. Pneumatic sorting is the mainstream method. However, due to the overlapping suspension speeds of half-shells and eighth-shells, complete separation was not achieved. This paper proposes using a toothed vibrating screen to separate the two. Using EDEM to simulate and analyze the motion forms, collision processes, and stress conditions of walnut shells and kernels on the vibrating screen, the effectiveness of this method was demonstrated, and the mechanisms of shell–kernel retention and loss during the separation process were revealed. Results indicate that 1/8 kernels, being smaller, easily fall into tooth grooves and move upward step by step under the excitation force during reciprocating vibration. The 1/2 shells, being larger, are difficult to fall into the teeth grooves, and their smooth surfaces cause them to slide easily, moving downward continuously under the action of reciprocating vibration and gravity. Using the cleaning rate and loss rate as evaluation indicators, it was found that as the inclination angle of the vibrating screen increased step by step, the cleaning rate consistently increased monotonously. The loss rate initially rose slowly, then surged sharply after reaching 22°, at which point the loss rate was at its lowest, around 10%, and the cleaning rate was at its maximum, at 95%. The shortest retention time of walnut shells on the screen is 2.85 s, and the longest is 10.6 s, with the number of collisions being 458 and 2619, respectively; the collisions between the shells and the kernels account for 51.8%. The failure to thoroughly separate is due to the shell and kernel entangling within the separation area, making it impossible to segregate them. They enter the opposite region, collide, and cause loss and retention phenomena. Full article

Keratin is a fibrous structural protein found in various natural materials such as hair, feathers, and nails. Its high stability and cross-linked structure make it resistant to degradation by common proteases, leading to the accumulation of keratinous waste in various industries. In this study, we developed and validated an effective bioinformatics-driven strategy for mining novel keratinase genes from the Esmatlas (ESM Metagenomic Atlas) macrogenomic database. Two candidate genes, ker820 and ker907, were identified through sequence alignment, structural modeling, and phylogenetic analysis, and were subsequently heterologously expressed in Escherichia coli Rosetta (DE3) with the assistance of a solubility-enhancing chaperone system. Both enzymes belong to the Peptidase S8 family. Enzymatic characterization revealed that GST-tagged ker820 and ker907 exhibited strong keratinolytic activity, with optimal conditions at pH 9.0 and temperatures of 60 °C and 50 °C, respectively. Both enzymes showed significant degradation of feather and cat-hair keratin. Kinetic analysis showed favorable catalytic parameters, including $K_m$ values of 9.81 mg/mL (ker820) and 5.25 mg/mL (ker907), and $V_{max}$ values of 120.99 U/mg (ker820) and 89.52 U/mg (ker907). Stability tests indicated that GST-ker820 retained 70% activity at 60 °C for 120 min, while both enzymes remained stable at 4 °C for up to 10 days. These results demonstrate the high catalytic capacity, thermal stability, and substrate specificity of the enzymes, supporting their classification as active keratinases. This study introduces a promising strategy for efficiently discovering novel functional enzymes using an integrated computational and experimental approach. Beyond keratinases, this methodology could be extended to screen for enzymes with potential applications in environmental remediation. Full article