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- 摘要：This paper first investigates the spectra of the product
- 摘要：The study was to investigate the aromatic derivatives and evaluate their antimicrobila activity from the endophytic fungus，Fusarium solani PGS19，isolated from the mangrove plant Bruguiera gymnorrhiza in the Nansha Wetland Nature Reserve. Firstly，the ethyl acetate extract of F. solani PGS19 was isolated and purified using various chromatographic techniques，including silica gel column chromatography，reversed-phase ODS medium-pressure preparation，semi-preparative high-performance liquid chromatography（HPLC），and thin-layer chromatography（TLC）. Then，the structures of the purified compounds were elucidated by modern spectroscopic methods. Finally，the antimicrobial activities of all isolated compounds were evaluated in vitro using broth microdilution method. Sixteen compounds were obtained from F. solani PGS19 and identified as 2-acetonyl-3-methyl-7-methoxynaphthazarin（1），3-methyletherfusarubin（2），solaniol（3），anhydrofusarubin（4），anhydrojavanicin（5），3-demethoxylfusarnaphthoquinone B（6），（2S，3S，4S）-8-dehydroxy-8-methoxyldihydronaphthalenone（7），dihydronaphthalenone（8），nepetoidin F（9），7-hydroxy-2，5-dimethyl-4H-1-benzopyran-4-one（10），methyl ferulate（11），p-hydroxyphenylacetic acid methylester（12），p-hydroxybenzaldehyde（13），4-hydroxyacetophenone（14），acetovanillone（15），and 3，4-dimethoxyacetophenone（16）. Among them，compound 9 was isolated from an endophytic fungus for the first time，expanding its biological source. Antibacterial activity assays indicated that compound 6 exhibited weak inhibitory effects against MRSA and Staphylococcus aureus，with MIC values of 100 µg/mL for both，while the remaining compounds showed no significant activity at the tested concentrations. This study further enriches the chemical diversity of secondary metabolites from mangrove endophytic F. solani.关键词：endophytic fungus;Fusarium solani;aromatic derivatives;antimicrobial activity48|26|0更新时间：2026-07-13
- 摘要：To solve the limitations of traditional adenosine content determination methods, such as complex sample preparation and time-consuming operations, in this study, Fourier transform infrared (FTIR) spectroscopy combined with chemometric methods was employed to establish a rapid detection model for adenosine content in Cordyceps sinensis. A rapid, efficient, and non-destructive quantitative method was proposed based on FTIR spectroscopy integrated with Simpson's integration rule. Spectral data were collected from 77 samples of C. sinensis. Through statistical analysis, 1 365 significant data points were screened from 1 868 original data points, determining five critical wavenumber regions (399.19-833.29, 1 033.36-1 380.46, 1 710.13-1 790.89, 1 870.56-3 020.78, and 3 980.46-3 999.71 cm-1). Four types of spectral characteristic variables—peak area (A), full width at half maximum (FWHM), area-to-height (H) ratio (A/H), and mean absorbance of the spectral band (MBA). A total of 62 samples (80%) were allocated as the training-validation set for 5-fold cross-validation to establish Multiple Linear Regression (MLR) and Partial Least Squares Regression (PLSR) models; the remaining 15 samples (20%) served as an independent test set for model generalization validation. FTIR characteristic analysis revealed that the principal absorption peaks of C. sinensis were located at 3 289.17 cm-1 (O—H stretching), 2 928.53 cm-1 (asymmetric C—H stretching), and 1 652.72 cm-1 (amide I band). Modeling results demonstrated that the A/H ratio feature exhibited optimal performance on the calibration set (MLR: R²=0.941±0.029), but suffered from severe overfitting (ΔR²=0.225); the PLSR-MBA combined model achieved the best cross-validation performance (R²=0.807±0.031, RMSE=0.189±0.005) with minimal overfitting (ΔR²=0.078). Independent test set validation further confirmed the superior predictive accuracy and robustness of the PLSR-MBA model (R²=0.886, RMSE=0.107), significantly outperforming the MLR-A/H model (R²=0.845, RMSE=0.169). The PLSR-MBA combined model achieves an optimal balance among fitting accuracy, generalization capability, and overfitting resistance, and is recommended as the preferred method for rapid quantitative analysis of adenosine content in C. sinensis. This study provides important theoretical basis and practical guidance for feature extraction and modeling strategy selection in spectral quantitative analysis of traditional Chinese medicines.关键词：chemometric methods;Cordyceps sinensis;adenosine;infrared spectroscopy;Simpson's rule;partial least squares regression;multiple linear regression37|29|0更新时间：2026-07-13
- 摘要：Dysregulation of manganese ion （Mn2+） homeostasis is closely associated with various diseases. However， the existing detection methods rely on expensive instruments and involve cumbersome operations， making it difficult to meet the demands for rapid and convenient analysis. In this study， a highly sensitive and selective colorimetric biosensor was constructed based on the cascade signal amplification principle of Mn2+-specific DNAzyme （Mn5V） and G-quadruplex/hemin DNAzyme for the detection of Mn2+ in complex biological matrices. The sensor employs a "hairpin-locked" substrate probe design. In the presence of Mn2+， Mn5V is activated and specifically cleaves the substrate strand， releasing a DNA fragment that folds into a G-quadruplex structure. The G-quadruplex then binds with hemin to form a complex with peroxidase-like activity， which catalyzes the TMB-H2O2 colorimetric reaction， enabling visual signal output. Our results demonstrated that the sensor exhibits excellent analytical performance for Mn2+， showing a good linear relationship in the range of 7.0×10-8 to 1.0×10-5 mol/L with a detection limit as low as 1.69×10-9 mol/L. The sensor also showed strong anti-interference ability against common coexisting metal ions. When applied to spiked recovery experiments in MCF-7 and A549 cell lysates， the recovery rates ranged from 98.00% to 101.00% with relative standard deviations below 4.3%， verifying its accuracy and reliability in complex biological samples. The cascade signal amplification colorimetric sensor constructed in this study provides a novel and efficient analytical tool for environmental monitoring and mechanistic research on the diseases related with manganese metabolism disorders.关键词：Mn2+;Mn5V;DNAzyme;colorimetric assay35|24|0更新时间：2026-07-13
- 摘要：SrTiO₃/LaAlO₃/SrTiO₃ （substrate） sandwich heterostructures were grown on SrTiO₃ （001） substrates by pulsed laser deposition. Atomic-scale structural characterization reveals gradient La diffusion near the n-type interface （SrTiO₃ substrate/LaAlO₃）， accompanied by partial reduction of Ti⁴⁺ to Ti³⁺， yielding a carrier concentration of approximately 4.98×10¹³ cm⁻². Ferroelectric-like displacement polarization vector analysis demonstrates that both interfaces exhibit a tail-to-head configuration： The SrTiO₃ polarization points toward the interface， while the LaAlO₃ polarization points away from the interface， with the LaAlO₃ polarization intensity being significantly stronger than that of SrTiO₃. At the n-type interface， the net negative bound charge generated by the tail-to-head ferroelectric-like polarization partially counteracts the electron accumulation driven by the polar discontinuity， resulting in an experimental carrier concentration approximately one order of magnitude lower than the theoretical value predicted by the polar catastrophe model. At the p-type interface， the net negative bound charge arising from the LaAlO₃ ferroelectric-like polarization acts synergistically with the hole requirement of the p-type polar discontinuity to drive two-dimensional hole gas formation. This study reveals the modulation mechanism of ferroelectric-like displacement polarization distributions induced by lattice distortions within the film on the dual-interface conduction behavior.关键词：SrTiO₃/LaAlO₃/SrTiO₃ heterostructure;two-dimensional electron gas;two-dimensional hole gas;polar catastrophe;ferroelectric-like displacement polarization8|12|0更新时间：2026-07-13
- 摘要：A minimal sediment model with diffusion is proposed. Firstly， the existence of Turing-Hopf bifurcation for the model is investigated； Secondly， the normal form of model at the Turing-Hopf bifurcation point is derived； Finally， the dynamics of model are analyzed by means of numerical results. The research indicates that near the Turing-Hopf bifurcation point， the model exhibits rich spatiotemporal dynamics， including the spatially homogeneous periodic solutions， spatially inhomogeneous periodic solutions and spatially inhomogeneous steady-state solutions.关键词：minimal sediment model;Turing-Hopf bifurcation;normal form;spatiotemporal dynamics60|49|0更新时间：2026-07-13
- 摘要：Melicope pteleifolia is a traditional medicinal herb in China and a vital raw material for renowned Chinese patent medicines such as Guangdong herbal tea and Sanjiu Weitai Granules. In the present study， M. pteleifolia seedlings were employed as experimental materials， and various types of microbial inoculants were foliar-sprayed to investigate the variations in seedling growth and development as well as rhizosphere soil microbial communities. The results demonstrated that microbial inoculant treatments significantly enhanced the plant height， the stem diameter， the seedling vigor index， and the number of leaf nodes of M. pteleifolia seedlings， among which the treatment with photosynthetic bacterial inoculant （T2） exhibited the most remarkable effect. Soil microbial analysis revealed that the application of compound EM inoculants （T1）， photosynthetic bacterial inoculant （T2）， or their combined application （T4） could all increase the number of soil operational taxonomic units （OTUs）， whereas other microbial inoculants resulted in a reduction in OTU abundance. It was observed that Proteobacteria was the dominant phylum in the rhizosphere soil of M. pteleifolia seedlings， and the application of all microbial inoculants elevated the relative abundance of Acidobacteriota in the rhizosphere soil. α diversity analysis indicated that the diversity of soil microbial communities was higher under T1， T2， and T4 treatments， and this diversity was positively correlated with seedling growth indices. In conclusion， T1， T2， and T4 can serve as suitable microbial fertilizer application schemes for M. pteleifolia at the seedling stage， among which Acidobacteriota and Bacteroidota may play pivotal roles in regulating rhizosphere microbial communities and improving soil fertility. This study provides a theoretical foundation for optimizing the cultivation techniques of M. pteleifolia.关键词：Melicope pteleifolia;microbial inoculants;rhizosphere microorganism;seedling stage26|33|0更新时间：2026-07-13
- 摘要：Let
- 摘要：A systematic investigation is conducted on the inverse problem of radiative coefficient reconstruction for a class of degenerate parabolic equations defined on semi-unbounded domains. The study begins by introducing an exact artificial boundary condition，which effectively reduces the original problem on the semi-unbounded region to an equivalent formulation on a bounded domain. Within the optimal control framework，the inverse problem is reformulated as a minimization problem. A priori estimates for the direct problem are derived，and the existence of a minimizer for the control functional is established，along with the necessary conditions satisfied by the extremum. The uniqueness and stability of the minimizer are demonstrated through an analysis based on these necessary conditions. Finally，based on the necessary optimality conditions，a gradient-based optimization algorithm was designed，and numerical examples were presented to demonstrate its effectiveness.关键词：Semi-unbounded degenerate parabolic equation;radiative coefficient inversion;artificial boundary;optimal control;well-posedness19|16|0更新时间：2026-07-13
- 摘要：The Zoige Basin， located on the northeastern Qinghai-Tibet Plateau， is a geomorphic unit highly sensitive to climate change. Widespread continuous aeolian deposits in this region provide valuable insights into regional surface processes and climate changes. This study investigated the loess-paleosol sequence at Kesheng Village （KSC） on the second terrace of the Yellow River in the Maqu Valley. Based on geochemical elemental analysis， micromorphological observation， and optically stimulated luminescence （OSL） dating， we reconstructed the chemical weathering history of the profile and revealed the phased climatic evolution since 13.2 ka. The results indicate that： 1） Stable aeolian dust accumulation commenced on the second terrace of the Yellow River at around 13.2 ka， forming a continuous and complete loess-paleosol sequence. From bottom to top， this sequence comprises loess L1（13.2~8.5 ka）， paleosol S0（8.5~3.0 ka）， loess L0（3.0~1.2 ka）， and modern soil MS （1.2 ka to present）. 2） The KSC profile is generally in the initial stage of chemical weathering （mean CIA=59.8）. Although the paleosol exhibits higher weathering intensity than the loess units， it remains within the initial weathering stage. The weathering intensity follows the order： paleosol S0 （mean CIA=62.3）
- 摘要：In 2023， Tainan experienced a severe dengue fever epidemic， the spread of which was influenced by complex environmental factors. This study analyzes the spatiotemporal patterns of dengue fever transmission in Tainan and identifies the key meteorological drivers， aiming to provide a scientific basis for local surveillance and evidence-based prevention. Monthly dengue case data and meteorological records for Tainan from January to December 2023 were analyzed using a standard deviational ellipse analysis， Moran’s I， correlation analysis， multicollinearity diagnostics， and a Bayesian spatiotemporal model. The findings reveal a clear temporal pattern of “increase-peak-decline” in case numbers for the full year of 2023. Spatially， the epidemic evolved through four stages：sporadic occurrence， random distribution， clustering， and eventual dissipation. The relative risks of meteorological factors followed the order： number of rainy days
- 摘要：An aerial image detection algorithm named MA-YOLOv11 is proposed based on YOLOv11. First，the SE-C3k2 module is designed to preserv the features of small branches while achieving lightweight. Second，the multi-scale shared convolution module replaces the SPPF module. Then，a novel HMA-Net network structure is constructed by incorporating the MAFPN architecture，adding a small target detection head P2，and reducing redundant paths. This enhances the interaction between shallow detail information and high-level semantic information，thereby improving the detection accuracy for small targets. Finally，a multi-scale attention detection head is employed to effectively handle scenes with leaf occlusion. Experimental results show that compared to the baseline model，the improved MA-YOLOv11 model increases of 4.2% in precision，4.1% in recall，and 5.2% in the mAP50 metric，validating the effectiveness of this method for treeencroachment detection.关键词：tree invasion;YOLOv11;spatial channel reconstruction convolution27|45|0更新时间：2026-06-26
- 摘要：Existing studies mostly focus on sensing external environments and targets by drones， with limited attention to onboard perception of active external detection. To solve this problem， this paper proposes a photosensitive sensing anti-detection flight method for drone swarms. First， we develop a compact photosensitive sensor unit that measures ambient directional illumination at each point in space around the drone. Based on the above， we devise an anti-detection evasion strategy by combining online observation and history weighting， and couple it with a risk propagation anti-detection model to enable local evasion knowledge sharing and coordination within the swarm. In addition， an onboard photosensitive experimental platform is constructed for local directional light-intensity observation. Experimental results show that， in the single-drone scenario， compared with no avoidance strategy， the proposed approach reduces the mean exposure time inside the threat area by 27.90%， with a maximum heading change of 46.80° during avoidance. For the swarm-cooperative case， our approach can reduce the average swarm exposure time by 26.62% compared with the strategy without anti-detection， and by 9.39% compared with the traditional velocity averaging strategy. The results provide a useful reference platform， experimental data， and theoretical support for coordinated anti-detection flight in drone swarms.关键词：drone swarms;anti-detection;photosensitive sensing;swarm traversal;detection area22|46|0更新时间：2026-06-26
- 摘要：A top-down approach for measuring vehicle carbon emissions and allocating them to the road network was proposed. Utilizing the statistical energy consumption data of vehicles from public transit enterprises and carbon emission factors， calculation methods for Battery Electric Vehicles （BEVs）， Plug-in Hybrid Electric Vehicles（PHEVs）， and traditional fuel vehicles were studied. Relying on the longitude， latitude， and vehicle speed parameters from high-frequency GPS data，
- 摘要：In practical intelligent transportation systems，failures of IoT may lead to data interruption， underscoring the importance of trajectory data generation algorithms. Existing trajectory generation methods can be categorized into two types， both of which exhibit limitations. Physics-based algorithms are unable to adapt to dynamically changing traffic scenarios， whereas data-driven methods tend to overlook interactions among vehicles. To address complex scenarios such as intersections， this paper proposes a trajectory generation method based on a conditional diffusion model. The proposed method introduces a motif matrix to quantify the influence of surrounding vehicles on the target vehicle，and employs a graph attention mechanism to accurately identify key neighboring vehicle information， and the conditional information is incorporated into the reverse denoising process of the diffusion model to generate vehicle trajectories. Experiments conducted on the Nuscenes dataset and a self-collected trajectory dataset demonstrate that the proposed method outperforms existing mainstream models across multiple accuracy evaluation metrics and is more consistent with kinematic principles.关键词：intelligent transportation;vehicle trajectory generation;conditional diffusion model14|21|0更新时间：2026-06-25
- 摘要：Camellia granthamiana is a plant species endemic to China with a small population， and is listed as a key protected species in Guangdong Province. Studies on its community structure are of great significance for its conservation and management. In this research， plot surveys were conducted in five C. granthamiana communities distributed in Guangdong Province， and the survival status of the species was analyzed from three dimensions： Community structure， species diversity， and phylogenetic structure. The results showed that： （1） Among the five communities， the age structure of C. granthamiana populations was of the growing type. In Baixi of Zijin County （BX-1， BX-2） and Heishiding （HSD-1）， C. granthamiana was the dominant species in the lower and middle layers of the arbor layer， with sound population regeneration； whereas in the community of Mount Qiniangshan in Shenzhen （QNS-1， QNS-2）， the species had a very small population size and existed mainly as an associated species. （2） QNS-1 had the highest species richness and evenness， with the most stable community structure； by contrast， BX-1 had a high dominance of C. granthamiana but a relatively low species evenness. （3） The deep-level phylogenetic structure of QNS-1 and QNS-2 tended to be clustered， indicating that habitat filtering played a leading role in community assembly. On the other hand， the deep-level phylogenetic structure of BX-1， BX-2 and HSD-1 showed a divergent pattern， suggesting that competitive exclusion was the dominant process in community assembly. For the shallow-level phylogenetic structure， the plots QNS-2， BX-1 and BX-2 exhibited a clustered distribution， which reflected the filtering effect of environmental conditions on the composition of closely related species in the community； while the plots QNS-1 and HSD-1 showed a divergent pattern， indicating that competitive exclusion mainly acted among closely related species. （4） The plot QNS-1 is located in the transition zone between the southern subtropical and northern tropical zones， which had the highest phylogenetic diversity， and the most complex species composition. This study reveals that the endangered status of C. granthamiana is the combined result of its narrow geographic distribution， fragile population regeneration ability， human interference and environmental screening. In summary， this study systematically clarifies the structure and construction mechanisms of the natural communities of C. granthamiana based on the data of community ecology and phylogenetics， providing a theoretical basis for the implementation of in-situ conservation and population restoration.关键词：Camellia granthamiana;community structure;species diversity;phylogenetic diversity44|73|0更新时间：2026-05-25
- 摘要：Polycyclic aromatic hydrocarbons （PAHs） are a class of persistent organic pollutants widely distributed in the air， water and soil. They are teratogenic， carcinogenic and mutagenic， posing a serious threat to the safety of aquatic ecosystems. As primary producers in aquatic ecosystems， algal photosynthetic systems are sensitive targets of PAHs toxicity， but the mechanisms of PAHs-induced damage and transcriptional regulation on algal photosynthetic systems remain unclear. In this study， the model freshwater green alga Raphidocelis subcapitata was used as the research object， combining chlorophyll fluorescence imaging technology and transcriptomic analysis to explore the effects of PAHs on the algal photosynthetic system and its regulatory mechanism. The results showed that the inhibitory effect of benzo［a］pyrene on the maximum photochemical efficiency of R. subcapitata was generally weaker than that of phenanthrene （PHE） and pyrene （PYR）. The electron transport rate of algae in the PHE and PYR treatment groups decreased to 43% and 49% of the control group， respectively， while PAHs exposure had little effect on the non-photochemical quenching coefficient of algae. The expression of five key genes in the algal photosynthetic system （cabII-1， LHCA4， LHCA5， PsbP and PsAN） was time-dependent， showing a significant upward trend on days 3 to 5 of exposure and decreasing on day 7. With the extension of exposure time， the transcriptional regulation mechanism of the algal photosynthetic system gradually became imbalanced， eventually leading to continuous damage to photosynthetic function. This study clarified the damage mechanism and transcriptional regulation characteristics of PAHs on the algal photosynthetic system at the physiological and molecular levels， providing a theoretical reference for the ecotoxicological study of PAHs and the assessment of aquatic ecological risks.关键词：polycyclic aromatic hydrocarbons;Raphidocelis subcapitata;transcriptomics;photosynthesis43|57|0更新时间：2026-05-25
- 摘要：As a significant pathogen of marine fish， Vibrio harveyi has caused huge economic losses of marine economic fish farming industry in China. In this study， we investigated the changes of intestinal microbial community structure and immune responses in Epinephelus coioides during V. harveyi infection. Results showed that V. harveyi infection altered the intestinal microbial community structure： the relative abundance of Proteobacteria decreased from 79.06% to 56.22%， while Firmicutes increased from 5.46% to 12.90%， Bacteroidetes changed from 2.78% to 9.80% and Actinobacteria changed from 1.97% to 2.47%， indicating that the emergence or increased relative abundance of potential pathogens such as Pseudoalteromonas， and decreased proportions of beneficial bacteria such as Psychrobacter. Meanwhile， differentially expressed genes enriched in GO terms and metabolic pathways related to immunity and antioxidant defense， including lysozyme activity， peptidoglycan muralytic activity， oxidoreductase activity and glutathione metabolism. These findings reveal that pathogenic bacteria can directly influence the structure of intestinal microbial community structure， as well as the extent of changes in host immune organs and key immune genes. Therefore， it is important to protect the intestinal health of farmed fish for disease prevention.关键词：Vibrio harveyi;Epinephelus coioides;gut microbiome;differentially expressed genes45|75|0更新时间：2026-05-25
- 摘要：Twenty-five hybrids as andrographolide（AG） molecular structural form similaritity analogues AG-Sn（n=1-25） were designed and synthesized，where the flexible trans-decahydronaphthalene with exocyclic double bond moiety of AG was replaced by rigid naphthalene ring，and α，β-unsaturated-γ-butyrolactone was replaced by flexible linear α，β-unsaturated amide. The total yield of these 11-step reactions was 29%-35%. All hybrids are reported here for the first time. The experimental results revealed that the α，β-unsaturated amide scaffold significantly influences the anticancer activity of these hybrids. Just the same as AG，hybrids with rigidity，high steric hindrance，and high-tension substituents on the nitrogen atom of amide bond including AG-S2，AG-S4，AG-S5，AG-S6，AG-S7，and AG-S16 were demonstrated with good antitumor activity against rat glioma cells（C6），human liver cancer cells（HepG-2），human colon adenocarcinoma cells（Caco2），human malignant melanoma cells（A-375），and human breast cancer cells（MDA-MB-231），exhibiting broad-spectrum anticancer activity. Among them，compound AG-S2 exhibits the most prominent anticancer activity against C6，with an IC50 value of（0.9±0.2） μmol/L，which is 10-fold more active than that of AG. All these six compounds were indicated with higher inhibitory activity on HepG-2 cells than that of AG. The structure-activity relationship（SAR） study reveals that hybrids with α，β-unsaturated amide bonds with double substitutions on nitrogen atom generally exhibit better anticancer activity. All the above results indicate that molecular structural form similarity is an effective way to search for new drug candidates.关键词：molecular structural form similarity;andrographolide;antitumor;drug design;drug synthesis49|42|0更新时间：2026-05-25
- 摘要：The existence of solutions for a class of superlinear second-order discrete Neumann boundary value problems of the form
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