Search Results (48)

Soil organic carbon (SOC) is an important part of the global C pool and is sensitive to climate change. The SOC content and fractions of rice paddies along four elevations (250, 1150, 1600 and 1800 m) on the same slope in four seasons (spring, summer, autumn and winter) at Yuanyang Terrace in southwest China were investigated, and their relationship with environmental factors was analyzed. The contents of SOC, unprotected SOC (uPOM), physically protected SOC (pPOM) and biochemically protected SOC (bcPOM) in rice paddies at a low elevation (250 m), were significantly lower by 49–51% than those at relatively high elevations (1600 m and 1800 m). Among the SOC fractions, the highest proportion (33–50%) was uPOM, followed by pPOM and bcPOM (accounting for 17–40%), and the lowest proportion was chemically protected SOC (cPOM). In addition, there were interseasonal differences among the contents of SOC fractions, with a significantly higher content of SOC, uPOM and pPOM at an elevation of 1600 m in summer than in the other three seasons, whereas the cPOM content at an elevation of 250 m in spring was significantly higher than in the other three higher elevations. According to the redundancy analysis (RDA), total nitrogen was the key environmental factor, with an explanatory degree of 56% affecting the contents of SOC and its fractions. Thus, the SOC content increased with increasing elevation, and physical and biochemical protection were potential stabilization mechanisms responsible for their stability in the rice paddy of Yuanyang Terrace. These results provides empirical evidence for the elevational distribution patterns and seasonal dynamics of SOC fractions in rice paddies across Yuanyang Terrace. These findings highlight the importance of physical and biochemical protection mechanisms in stabilizing SOC in rice paddies, which could enhance long-term C sequestration and contribute to climate change mitigation in terraced agroecosystems. Full article

Since carbohydrate antigen 19-9 (CA 19-9) is a significant biomarker for the clinical diagnosis and treatment of pancreatic cancer, a sensitive sandwich-type immunosensor was proposed with an epoxy functionalized covalent organic framework (EP-COF_TTA-DHTA) as the antibody carrier and an electroactive COF_{TTA-2,6-NA(OH)2} as the signal amplification probe for the sensitive detection of CA 19-9. The flexible covalent linkage between the epoxy-functionalized EP-COF_TTA-DHTA and the antibodies was employed to improve the dynamics of the antigen–antibody interaction significantly. Meanwhile, AuNPs@COF_{TTA-2,6-NA(OH)2} with abundant electroactive sites enhanced the current response of the immunoreaction significantly. After optimizing the incubation time and concentration of the antibody, CA 19-9 was quantitatively detected by differential pulse voltammetry (DPV) based on the sensitive sandwich-type immunosensor with a low detection limit of 0.0003 U/mL and a wide linear range of 0.0009–100 U/mL. The electrochemical immunosensor exhibits high specificity, stability and repeatability, and it provides a feasible and efficient method for the pathologic analysis and treatment of tumor markers. Full article

Increased consumer awareness on food safety has spurred the development of detection techniques for pesticide residues. In this study, a rapid detection card on the basis of enzyme action was developed for the visual detection of pesticides, in which the thermally crosslinked and surface-decorated polyvinyl alcohol/citric acid nanofiber mat (PCNM) was employed as a novel immobilization matrix for acetylcholinesterase (AChE). The PCNM, crosslinked at 130 °C for 50 min, exhibited appropriate microstructure and water stability, making it suitable for AChE immobilization. The activation of carboxyl groups by surface decoration resulted in a 2.5-fold increase in enzyme loading capacity. Through parameter optimization, the detection limits for phoxim and methomyl were determined to be 0.007 mg/L and 0.10 mg/L, respectively. The detection card exhibited superior sensitivity and a reduced detection time (11 min) when compared to a commercially available pesticide detection card. Furthermore, the detection results of pesticide residues in fruit and vegetable samples confirmed its feasibility and superiority over commercial alternatives, suggesting its great potential for practical application in the on-site detection of pesticide residues. Full article

Autoimmune hepatitis (AIH) is linked to an increased risk of hepatocellular carcinoma (HCC). However, the precise connection between the two remains unclear. GPR81, a G-protein-coupled receptor located on the membranes of various cell types, plays a role in numerous physiological processes. We established an AIH animal model and activated GPR81 using the agonist 3,5-dihydroxybenzoic acid (3,5-DHBA). Additionally, the effect of GPR81 inhibition on tumor and immune cell dynamics was examined using the HepG2, Hep3B, and Hepa1-6 cell lines with the antagonist 3-hydroxybutyric acid (3-OBA). Our results demonstrated that 3,5-DHBA treatment reduced T cell and pro-inflammatory cytokine secretion, while MDSC secretion increased, inhibiting Concanavalin A (Con A)-induced AIH. The inhibition of GPR81 by 3-OBA suppressed HCC cell proliferation and invasion, reduced tumor volume and weight, and downregulated PD-L1 expression. Furthermore, CTL and DC activity in the spleen and tumors increased, while MDSC activity decreased. This study confirms that GPR81 plays an important role in both inflammation and tumorigenesis, suggesting that GPR81 may serve as a bridge in the transformation of inflammation into cancer. Modulating GPR81 activity may provide a novel therapeutic strategy for hepatitis and cancer. Full article

Soil organic carbon (SOC) represents the most dynamic component of the soil carbon pool and is pivotal in the global carbon cycle. Global temperature rise and increasing drought severity are now indisputable realities, making soil organic carbon cycling under climate warming a critical research priority. This review elucidates the mechanism of the SOC response to temperature increase in terms of both extrinsic and intrinsic factors. The extrinsic factors are temperature elevation methods, rainfall, and land use. Different methods of temperature increase have their own unique advantages and disadvantages. Indoor warming methods exclude other factors, making temperature the only variable, but tend to ignore carbon inputs. In situ field warming and soil displacement methods help researchers explore the response of the complete ecosystem carbon cycle to temperature increase but cannot exclude the interference of factors such as rainfall. Elevated rainfall mitigates the adverse effects of elevated temperatures on organic carbon sequestration. In addition, the response of SOC to temperature elevations vary among different land use types. The temperature sensitivity of SOC is higher in peatland (high organic matter) alpine meadows (colder regions). The intrinsic factors that affect the response of SOC to elevated temperatures are SOC components, microorganisms, SOC temperature sensitivity, and SOC stability. The SOC decomposition rate is influenced by variations in the ratios of decomposable (easily oxidizable organic carbon (EOC), dissolved organic carbon (DOC), and microbial biomass carbon (MBC)) and stabilizing (inert organic carbon (IOC), alkyl carbon, and aromatic carbon) SOC to total organic carbon (TOC). Furthermore, temperature elevations also affect the soil microenvironment, resulting in microbial community reorganization such as changes in bacterial and fungal ratios and abundance. At the same time, soil aggregates, clay minerals, and iron and aluminum oxides protect the SOC, making it difficult to be utilized by microbial decomposition. The systematic clarification of the mechanism behind the SOC response to higher temperatures is crucial for accurately predicting and modeling global carbon cycles and effectively responding to the loss of SOC pools due to global temperature elevations. Full article

Fault location technology is crucial for enhancing the efficiency of fault maintenance and ensuring the safety of the power supply in small current grounding systems. To address the challenge that traditional single-end positioning methods experience when identifying the reflected wave head and that the adaptability of wave head calibration methods is typically limited, a single-end location method of modulus wave velocity differences based on marine predator algorithm optimized multivariate variational mode decomposition (MVMD) and morphological gradient is proposed. Firstly, the minimum comprehensive entropy kurtosis ratio is used as the fitness function, and the marine predator algorithm is used to realize the automatic optimization of the mode number and penalty factor of the multivariate variational mode decomposition. Therefore, with the goal of decomposing the traveling wave characteristic signals with the most significant traveling wave characteristic information and the lowest noise component, the line-mode traveling wave and the zero-mode traveling wave are accurately decomposed. Secondly, the intrinsic mode function component with the smallest entropy kurtosis ratio is selected as the line-mode traveling wave characteristic signal and the zero-mode traveling wave characteristic signal, respectively, and the arrival time of the wave head is accurately calibrated by combining the morphological gradient value. Finally, the fault distance is calculated by the modulus wave velocity difference location formula and compared with the variational mode decomposition-Teager energy operator (VMD-TEO) method and the empirical mode decomposition _first-order difference method. The results show that the proposed method has the highest accuracy of positioning results, and the algorithm time is significantly reduced compared with the VMD-TEO method, and it has strong adaptability to different line types of faults, different fault initial conditions, and noise interference. Full article

This study investigated the effects of microenapsulated hydrolyzed tannins (MHTs) on the growth performance and meat quality of Zhongshan shelducks. A total of 288 healthy Zhongshan shelducks with an average initial weight of 1790.27 ± 0.14 kg were randomly divided into four groups through a 56 d experiment period and were fed a basal diet supplemented with 0 (CON), 400, 800, and 1600 mg/kg MHTs, respectively. Results showed that 400 and 800 mg/kg MHTs improved the final body weight, average daily gain, glutathione peroxidase activity, and total antioxidant capacity compared to CON (p ≤ 0.05). The diet supplemented with 400 mg/kg MHTs decreased shear force and 800 mg/kg MHTs increased the yield of pectoralis major muscle compared to CON (p ≤ 0.05). Dietary MHTs increased inosine monophosphate content and decreased percentage C14:0 content in meat; however, the b*45 min value, 48 h drip loss, and shear force were increased but the percentage intramuscular fat (IMF) content was decreased in pectoralis major muscle with the increase in MHTs (p ≤ 0.05). Compared to CON, 400 and 800 mg/kg MHTs increased the percentage content of IMF, C18:1n-9, C18:2n-6, monounsaturated fatty acids, polyunsaturated fatty acids, and unsaturated fatty acids in pectoralis major muscle (p ≤ 0.05). Furthermore, 400 and 800 mg/kg MHTs improved the lipid metabolism of IMF deposition, fatty acid uptake, and adipogenesis by activating the peroxisome proliferator-activated receptor gamma pathway to regulate fatty acid synthetase and lipoprotein lipase genes. In conclusion, diets supplemented with 400 and 800 mg/kg MHTs could improve growth, meat quality, antioxidant capacity, and lipid metabolism in Zhongshan shelducks. Full article

Aquilaria spp. are a highly valuable plant species found in the Chinese herbal medicine and agarwood fragrance supplement industries for fumigation, combustion and perfume. The phytochemical composition of agarwood oils (extracts) was derived from Aquilaria sinensis and its subspecies ‘Qi-Nan’ using supercritical CO₂ extraction technology. Gas chromatography connected with a mass spectrometry apparatus was employed for qualitative and quantitative analyses. Comparing the agarwood oils from six planting areas, 12 common components were obtained, among which sesquiterpenes and chromones had the highest relative content. Genetic and environmental factors had the greatest impact on the three chromones, especially on 2-phenyl-4H-chromen-4-one. According to the PCA and PLS-DA models, the ‘Qi-Nan’ was derived from a variety selected from the native A. sinensis, and the difference in the volatile components was able to indirectly prove that it was genetically heterogeneous with the native A. sinensis. Using the 73 components obtained from GC–MS analysis, the VIP values and S-plots were generated using the OPLS-DA model. Seven components with VIP values > 1.0 were selected from two groups of agarwood oils of the native A. sinensis and ‘Qi-Nan’ subspecies. In addition, by analyzing 12 common components, the differential components with VIP values > 1 were 2-phenyl-4H-chromen-4-one and 2-(4-methoxyphenethyl)-4H-chromen-4-one. Chromones were the main component of agarwood oils extracted by supercritical CO₂, and 2-phenyl-4H-chromen-4-one could be used as a volatile marker, especially in the ‘Qi-Nan’ subspecies, where this marker exhibited more prominent characteristics. Full article

Biodegradable polylactic acid (PLA) was used to fabricate nonwoven fabrics via the melt blowing process, followed by electrospinning to deposit a nanofiber membrane. This composite process yielded PLA melt-blown/electrospun composite materials with excellent filtration performance. The effects of the solution concentration and spinning duration on the composite structure and material performance were investigated. The optimal composite was produced using a 10 wt.% PLA spinning solution prepared with a solvent mixture of dichloromethane (DCM) and N, N-dimethylformamide (DMF) in a 75/25 weight ratio. The process parameters included a spinning duration of 5 h, 18 kV voltage, 1.5 mL/h flow rate, and 12 cm collection distance. The resulting composite achieved a filtration efficiency of 98.7%, a pressure drop of 142 Pa, an average pore size of 5 μm, and a contact angle of 138.7°. These results provided optimal process parameters for preparing PLA melt-blown/electrospun composite filtration materials. This study highlights the potential of hydrophobic PLA composites with high filtration efficiency and low air resistance as environmentally friendly alternatives to traditional non-degradable filtration materials. Full article

To improve cotton yield in salinized arid fields, excess salt is removed and phosphorus content is increased. Adjusting phosphate fertilizer timing with water and fertilizer reduces phosphorus binding with calcium ions. Salt removal precedes phosphate application, enhancing soil phosphorus availability and promoting better growth. However, the optimal time for delaying phosphate fertilizer drip irrigation remains unclear. Therefore, this study evaluated the total salt, soil available phosphorus, and cotton yield under the condition of delayed phosphate fertilizer application. We conducted a field experiment using a completely randomized design to adjust the timing of phosphatic fertilizer application and apply the same amount of pure phosphorus. Specifically, “t” was defined as the total duration of one irrigation cycle, and the starting points for phosphorus application were as follows: T1, 1 h; T2, 1 h + 1/3 t h; T3, 1 h + 2/3 t h; CK, 1/3 t h. These values represent the duration of salt leaching through irrigation in each treatment. Phosphate fertilizer was applied to the soil after salt washing was complete. The results revealed that the T2 treatment exhibited the highest SPAD value (64.53), which was 11.46% and 15.48% higher than that of the T1 and T3 treatments. The 0–20 and 20–40 cm soil layers under the T2 treatment had the highest pH values of 9.12 and 9.37, representing increases of 1.93%, 1.21%, 4.50%, and 1.38% compared with T1 and T3 treatments, respectively (p < 0.05). At the bud stage, the Olsen-P in the T2 treatment was 82.86% and 26.53% higher than that in the T1 and T3 treatments, respectively (p < 0.05). The T2 treatment achieved the highest yield of 6492.09 kg/hm², which was 31.47%, 31.53%, and 2.77% higher than that of T1, T3, and CK. Overall, the T2 treatment increased cotton yield and reduced the adsorption of calcium ions to available phosphorus in salinized soil. This study provides an effective technical approach for the sustainable development of salinized cotton fields in Xinjiang. Full article

The failure state of the natural gas pipelines in underground space may cause explosions, and an explosion flow field is affected by the structure of the venting duct. Based on FLACS software v9.0, the influence of the explosion vent and venting duct on temperature and pressure fields is studied. The results show that when the area of the explosion vent increases from 0 to 100 cm², the peak overpressure decreases by half, and the overpressure drops to zero within 0.3 s. For different L-type venting ducts, when the structural coefficient is less than 5, the peak overpressures and pressure variations are similar. When the structural coefficient is equal to 5, the peak overpressure significantly decreases, and the time to reach the peak value is extended by 50%. From the perspective of achieving a safe and efficient venting effect, the optimal structural coefficient is 5 for the L-type venting duct. Full article

Benzene, toluene, and xylene (BTX) co-exist in human environments, yet their individual and combined effects on genetic damage at low exposure levels are not fully understood. Additionally, single nucleotide polymorphisms in microRNAs (mirSNPs) might be involved in cancer etiology by affecting the related early health damage. To investigate the influence of BTX exposure, mirSNPs, and their interactions on genetic damage, we conducted a cross-sectional study in 1083 Chinese petrochemical workers, quantifying the BTX cumulative exposure levels and multiple genetic damage biomarkers. Additionally, we genotyped multiple common mirSNPs. Benzene and a BTX mixture were positive associated with the olive tail moment (OTM) and tail DNA% (p < 0.05). Higher levels of toluene and xylene enhanced the association of benzene with genetic damage levels. Genotypes and/or mutant allele counts of miR-4482-related rs11191980, miR-4433-related rs136547, miR-27a-related rs2594716, miR-3130-related rs725980, and miR-3928-related rs878718 might significantly influence genetic damage levels. Stronger effect estimates of benzene/BTX exposure were found in carriers of miR-196a-2-related rs11614913 heterozygotes and of wild homozygotes of miR-1269b-related rs12451747, miR-612-related rs12803915, and miR-4804-related rs266437. Our findings provide further support of the involvement of BTX co-exposure, mirSNPs, and their gene–environment interactions in determining the severity of DNA strand break in a complex manner. Full article

In arid areas, water shortage has become a major bottleneck limiting the sustainable development of agriculture, necessitating improved water use efficiency and the full development of innovative water-saving irrigation management technologies to improve quality. In the present study, tomato (Solanum lycopersicum cv. Micro Tom) fruits were used as materials, and different irrigation frequencies were set during the fruit expansion stage. The normal treatment (CK) was irrigated every three days, while the water deficit treatments were irrigated at varying frequencies: once every 4 days (T1), 5 days (T2), 6 days (T3), 7 days (T4), and 8 days (T5). These corresponded to 80%, 70%, 60%, 50%, and 40% of the maximum field moisture capacity (FMC), respectively, with CK maintaining full irrigation at 90% of the maximum FMC. The water deficit treatment T3, with less stress damage to plants and the most significant effect on fruit quality improvement, was selected based on plant growth indices, photosynthetic characteristics, chlorophyll fluorescence parameters, and fruit quality indices, and its effects on carotenoids, glycolic acid fractions, and volatile compounds during tomato fruit ripening were further investigated. The outcome indicated that moderate water deficit significantly increased the carotenoid components of the tomato fruits, and their lycopene, lutein, α-carotene, and β-carotene contents increased by 11.85%, 12.28%, 20.87%, and 63.89%, respectively, compared with the control fruits at the ripening stage. The contents of glucose and fructose increased with the development and ripening of the tomato fruits, and reached their maximum at the ripening stage. Compared to the control treatment, the moderate water deficit treatment significantly increased the glucose and fructose levels during ripening by 86.70% and 19.83%, respectively. Compared to the control conditions, water deficit conditions reduced the sucrose content in the tomato fruits by 27.14%, 18.03%, and 18.42% at the mature green, turning, and ripening stages, respectively. The moderate water deficit treatment significantly increased the contents of tartaric acid, malic acid, shikimic acid, alpha ketoglutaric acid, succinic acid, and ascorbic acid, and decreased the contents of oxalic acid and citric acid compared to the control. The contents of total soluble sugar and total organic acid and the sugar–acid ratio were significantly increased by 48.69%, 3.71%, and 43.09%, respectively, compared with the control at the ripening stage. The moderate water deficit treatment increased the fruit response values to each sensor of the electronic nose, especially W5S, which was increased by 28.40% compared to the control at the ripening stage. In conclusion, during the ripening process of tomato fruit, its nutritional quality and flavor quality contents can be significantly improved under moderate (MD) deficit irrigation treatment. The results of this experiment can lay the foundation for the research on the mechanism of water deficit aiming to promote the quality of tomato fruit, and, at the same time, provide a theoretical basis and reference for tomato water conservation and high-quality cultivation. Full article

Hulless barley is a cold-resistant crop widely planted in the northwest plateau of China. It is also the main food crop in this region. Phosphorus (P), as one of the important essential nutrient elements, regulates plant growth and defense. This study aimed to analyze the development and related molecular mechanisms of hulless barley under P deficiency and explore the regulatory genes so as to provide a basis for subsequent molecular breeding research. Transcriptome analysis was performed on the root and leaf samples of hulless barley cultured with different concentrations of KH₂PO₄ (1 mM and 10 μM) Hoagland solution. A total of 46,439 genes were finally obtained by the combined analysis of leaf and root samples. Among them, 325 and 453 genes had more than twofold differences in expression. These differentially expressed genes (DEGs) mainly participated in the abiotic stress biosynthetic process through Gene Ontology prediction. Moreover, the Kyoto Encyclopedia of Genes and Genomes showed that DEGs were mainly involved in photosynthesis, plant hormone signal transduction, glycolysis, phenylpropanoid biosynthesis, and synthesis of metabolites. These pathways also appeared in other abiotic stresses. Plants initiated multiple hormone synergistic regulatory mechanisms to maintain growth under P-deficient conditions. Transcription factors (TFs) also proved these predictions. The enrichment of ARR-B TFs, which positively regulated the phosphorelay-mediated cytokinin signal transduction, and some other TFs (AP2, GRAS, and ARF) was related to plant hormone regulation. Some DEGs showed different values in their FPKM (fragment per kilobase of transcript per million mapped reads), but the expression trends of genes responding to stress and phosphorylation remained highly consistent. Therefore, in the case of P deficiency, the first response of plants was the expression of stress-related genes. The effects of this stress on plant metabolites need to be further studied to improve the relevant regulatory mechanisms so as to further understand the importance of P in the development and stress resistance of hulless barley. Full article

In hyperspectral image (HSI) classification, convolutional neural networks (CNNs) and transformer architectures have each contributed to considerable advancements. CNNs possess potent local feature representation skills, whereas transformers excel in learning global features, offering a complementary strength. Nevertheless, both architectures are limited by static receptive fields, which hinder their accuracy in delineating subtle boundary discrepancies. To mitigate the identified limitations, we introduce a novel dual-branch adaptive convolutional transformer (DBACT) network architecture featuring an adaptive multi-head self-attention mechanism. The architecture begins with a triadic parallel stem structure for shallow feature extraction and reduction of the spectral dimension. A global branch with adaptive receptive fields performs high-level global feature extraction. Simultaneously, a local branch with a cross-attention module provides detailed local insights, enriching the global perspective. This methodical integration synergizes the advantages of both branches, capturing representative spatial-spectral features from HSI. Comprehensive evaluation across three benchmark datasets reveals that the DBACT model exhibits superior classification performance compared to leading-edge models. Full article