Table of Content

25 October 2025, Volume 53 Issue 10

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Traffic Safety

Analysis of Freeway Accident Factors Integrating Short-Term Traffic Flow

WEN Huiying, HUANG Junda, HUANG Kunhuo, ZHAO Sheng, CHEN Zhe, HU Yuqing

2025, 53(10):  1-13.  doi:10.12141/j.issn.1000-565X.240535

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The severity of freeway traffic accidents is collectively influenced by multiple factors, among which short-term traffic flow characteristics immediately preceding the incident play a particularly critical role. To syste-matically analyze the impact of short-term traffic flow states on injury severity, this study constructed a random parameter logit model accounting for mean heterogeneity, utilizing historical traffic accident data, ETC gantry transaction records, and meteorological data from Guangdong Province’s South 2nd Ring Expressway, Jiguang Expressway, and Western Coastal Expressway (2021—2022). The model was developed to investigate heterogeneous characteristics of accident contributing factors. A total of 29 potential variables were identified across four domains: road cha-racteristics, environmental conditions, traffic flow features, and crash attributes. Three discrete model specifications were employed to model injury severity: a standard multinomial logit model, a random parameter logit model, and a random parameter logit model that accounts for mean heterogeneity. Comparative analysis of model goodness-of-fit using pseudo-R², akaike information criterion (AIC), and Bayesian information criterion (BIC) demonstrated that the random parameter logit model accounting for mean heterogeneity exhibits superior performance in goodness-of-fit. This specification more accurately captures the heterogeneous characteristics of accident contributing factors. Further analysis based on the average elasticity of variables reveals that, at the 99% confidence level, 22 parameters significantly affect injury severity. Specifically, features such as six-lane bidirectional roads and improved visibility significantly reduce injury severity, whereas longer road rescue handling time, higher average speed and proportion of large trucks, and greater speed differentials between large and small vehicles are associated with increased injury severity. The findings of this study offer valuable insights for improving freeway accident prevention and management strategies.

Identifying Key Causes of Accidents for Autonomous Vehicles Based on CTGAN

ZHANG Zhiqing, YU Xiaozheng, ZHU Leipeng, SUN Yufeng, LI Yixin

2025, 53(10):  14-28.  doi:10.12141/j.issn.1000-565X.240378

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Clarifying the mechanism of traffic accidents involving autonomous vehicles is an important prerequisite for effectively preventing and controlling safety risks. Analysis of accident causation in autonomous vehicles is typically modeled on few-shot and unbalanced data, resulting in low predictive accuracy for under-represented classes. An analytical framework based on data augmentation can improve the prediction accuracy of models for minority classes. The sample size was increased and the dataset was balanced using techniques such as conditional tabular generative adversarial network (CTGAN), Copula generative adversarial network (CopulaGAN), synthetic minority oversampling technique (SMOTE), and adaptive synthetic sampling (ADASYN), and the quality of synthetic data with different methods was compared. Based on the synthetic data, five classification algorithms-logistic regression (LR), decision tree (DT), random forest (RF), extreme gradient boosting (XGB), and support vector machine (SVM)-were evaluated. Metrics such as recall, specificity, weighted F1score, and area under the ROC curve (AUC) were used to determine the optimal combination. Finally, the Shapley additive explanations (SHAP) framework was used to quantify the importance of key contributing factors to accidents. The results show that the marginal distribution score (0.96) and correlation score (0.92) of data generated by CTGAN are the highest, with an average quality of 0.94 for the synthetic data, which is significantly better than other methods. When CTGAN is combined with the random forest algorithm, the model performs excellently in metrics such as recall (0.82), specificity (0.84), and AUC (0.86), and it remains robust in test sets containing 10% label noise (with recall increased to 0.88), further verifying its applicability in complex scenarios. The analysis of key contributing factors indicates that road surface conditions (wet conditions significantly increase the risk of injury), nighttime driving (low light causes reduced sensor performance), and intersection and roadway complexity levels (complex scenarios increase detection delays) are the core factors leading to accidents. This study provides a key basis for the construction of autonomous driving test scenarios and the renovation of road infrastructure.

Analysis of Highway Driving Fatigue Patterns in Heavy Truck Drivers

LI Chen, CHEN Feng, DING Wenlong, PAN Xiaodong

2025, 53(10):  29-39.  doi:10.12141/j.issn.1000-565X.240411

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Long-distance heavy truck drivers are prone to fatigue when driving on highways, threatening road safety. To systematically investigate the fatigue characteristics and their progression of heavy truck drivers during prolonged highway driving, an on-road driving experiment was conducted for truck drivers operating continuously on highways. Cameras were mounted to continuously monitor the driver’s seat, with driving behaviors correlated to fatigue levels-such as the frequencies of rearview mirror-checking and non-driving-related movements-quantified through video analysis. An eye tracking device was utilized to acquire and process ocular metrics-including blink duration and pupil diameter-during driving sessions. Subsequent analysis employed function fitting, driving behavior characterization, and multilayer perceptron (MLP) modeling to examine the progression patterns of fatigue characteristics during prolonged highway driving, the correlation between fatigue manifestations and driving behaviors, and safety-critical time thresholds for continuous driving duration of truck drivers. The results indicate that the safe threshold for continuous driving time for truck drivers is between 3.6 and 3.7 hours. Regarding passive fatigue generated during driving tasks, detection of fatigue onset via mean blink duration occurred 5~15 minutes prior to drivers’ active fatigue countermeasures in 48.69% of observed instances. A notable reduction in passive fatigue frequency was observed during the 1.5~2.0 h interval of continuous driving. Statistical analysis revealed significant correlations between both rearview mirror-checking frequency and non-driving-related movements (NDRMs) with mean blink duration. An MLP model constructed using the frequencies of rearview mirror-checking, NDRM occurrences, and communication behaviors as predictors without ocular metrics achieved an 80.2% detection rate for passive fatigue during driving. These research outcomes provide theoretical foundations and practical references for developing video-based fatigue monitoring systems, implementing fatigue alerts, and enhancing driving safety for heavy trucks.

Numerical Simulation of Wind Field at Bridge-Tunnel Connection Section in Complex Mountainous Areas

HE Yongming, ZHANG Longlong, SUI Shengchun, WAN Yiming

2025, 53(10):  40-51.  doi:10.12141/j.issn.1000-565X.250075

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The complex and variable mountainous area causes the wind field to exhibit unsteady and non-stationary characteristics, posing significant challenges to traffic safety at bridge-tunnel connection sections. To study the variation law of the spatial characteristics of the wind field at the bridge-tunnel connection sections in complex mountainous area, this paper takes the mountainous terrain within an 8 km diameter range at the junction of G318 and S217 as the research background. It acquires the digital elevation model (DEM) of the study area’s terrain, and utilizes a reverse fitting method to construct mountain mass models for bridge-tunnel connection sections of five varying lengths. With reference to the standard 16-point wind rose diagram, inflow conditions were configured. The spatial distribution characteristics of wind fields at bridge-tunnel connection sections under various inflow conditions were obtained through numerical simulation. The results show that the error between the numerical simulation results and the on-site measured data is generally within 20%, indicating that the numerical simulation method has high accuracy. Under the condition that the slope of the mountain remains approximately unchanged, affected by the actual complex terrain, cross-bridge wind speeds, vertical wind profiles, and wind attack angles exhibit distinct characteristics at bridge-tunnel connection sections of varying lengths, though they demonstrate similar overall patterns. When the incoming flow is perpendicular to the bridge-tunnel connection section, the wind speed reaches the maximum at the mid-span due to the canyon acceleration effect. This acceleration effect increases as the length of the bridge-tunnel connection section decreases. Under other cases, due to the reduction effect of the high and steep mountains on both sides, the incoming flow decreases and the wind speed is the minimum along the bridge-tunnel connection section. The steep mountainous terrain and river bends significantly influence the vertical cross-bridge wind speed distribution. Within lower-elevation canyons, shorter bridge-tunnel connection sections experience more pronounced effects. Wind attack angles also exhibit substantial terrain-induced variations, predominantly manifesting as negative attack angles overall. The variation laws obtained from the numerical simulation study of the wind field in the bridge-tunnel connection section of complex mountainous areas can provide certain guidance and reference for the study of driving safety at bridge-tunnel connection sections.

Skid Resistance of Cement Concrete Grooved Pavements Based on a Longitudinal Friction Testing Model

ZHANG Dawei, YE Juntao, XIE Zhiyu

2025, 53(10):  52-59.  doi:10.12141/j.issn.1000-565X.250014

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Elucidating the interrelationship between pavement and tire factors and skid resistance is of significant importance for reducing traffic accident rates caused by insufficient pavement skid resistance. Through standardized field tests, three-dimensional point cloud data and corresponding friction coefficients were obtained from 100 measured points on real grooved cement concrete pavements. After horizontal calibration and noise reduction processing, reverse modeling was performed to establish pavement models that preserve pavement texture characteristics. Then, according to specifications, the geometric structure of a smooth tire for longitudinal friction testing was established, and a material model was built based on manufacturer-provided data, and a tire-pavement model was assembled and established in abaqus, and the validity of the tire model was verified by comparison with static pressure experiment data. Finally, the validity of the model was verified by comparing the finite element back-analysis values with the experimental measurement values, and the impacts of pavement texture, tire pressure, and speed on pavement skid resistance were analyzed. The results show that the tire model established in this study can reflect real working conditions, and the established tire-pavement model can accurately estimate the adhesion coefficient of the pavement, with an absolute error below 0.05; as the density of pavement surface peak points (S_pd) increases, the adhesion coefficient shows an upward trend at both high and low speeds, with a more significant influence at low speeds; with the rise of tire pressure, the adhesion coefficient at each test point exhibits a relatively consistent downward trend, with no significant difference in the magnitude of the decrease. Compared to speed, the impact of tire pressure on the adhesion coefficient is less significant. Compared to vehicle speed, tire inflation pressure demonstrates a less pronounced effect on friction coefficient. The friction coefficient asymptotically approaches a stable value with increasing speed, where this equilibrium is predominantly governed by the pavement’s macrotexture characteristics, while the direct influence of speed itself remains relatively limited.

Architecture & Civil Engineering

Analysis on Dynamic Performance of New-to-Old Concrete Interface in Prefabricated Members

CHEN Qingjun, ZHANG Yuqi, LEI Jun, WANG Yingtao, YAO Miaojin, LI Jiancong

2025, 53(10):  60-73.  doi:10.12141/j.issn.1000-565X.250045

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For prefabricated members, the reliable bonding of new-to-old concrete interface is the key to the formation of an integrated load-bearing system. Currently, both domestical and international scholars have conducted a series of studies on the static performance of the interface. However, the structures are often subjected to dynamic impact loads such as vehicle and ship collisions, heavy object impacts, and natural disasters during their service. Therefore, this paper studied the dynamic mechanical performance of the interface between new and old concrete in prefabricated structures. 210 prefabricated concrete components were investigated based on the split Hopkinson pressure bar test method. The research factors of this experiment include key parameters such as the average groove depth, the number of grooves, the interface inclination angle, and the combination of strength grades of new and old concrete, as well as the interface treatment methods (bonded rebar or not). The results indicate that factors such as the impact air pressure and the inclination angle of the specimen interface have a significant influence on the failure modes of the specimens, which can be classified into five categories based on the degree of damage and crack development characteristics. As the impact air pressure increases, the strain rate of specimens with different interface inclination angles gradually increases, with the 20° inclination angle specimens showing the most significant increase, while the 40° and 60° inclination angle specimens exhibit similar increases. With the increase in strain rate, the peak stress of all specimens shows an increasing trend. Under the same impact air pressure, specimens with a 40° interface inclination angle achieve relatively larger peak stress when the groove depth is greater, the number of grooves is higher, and the strength grade of the new concrete is increased. Bonded rebar can improve the peak stress of specimens under certain conditions. As the strain rate increases, the interface shear stress of all specimens also increases accordingly. Under the same concrete strength grade combinations, the shear stress of specimens with C1/C3 and C2/C3 is similar, both being greater than that of C1/C2. In particular, specimens with a 40°interface inclination angle exhibit higher shear stress at the interface. For specimens without bonded rebar, interface bearing capacity formulas were derived for three types: static-loaded without grooves, static-loaded with grooves, and impact-loaded with grooves. These formulas show good agreement with experimental results.

Influence of Particle Size on the Creep Behavior of Granular Materials Under Different Deviatoric Stress

LI Tao, SHU Jiajun, LI Yue, WAN Limin, WU Bingni, DENG Zhengding, HUANG Jingzhu, RUBEN Galindo

2025, 53(10):  74-85.  doi:10.12141/j.issn.1000-565X.240473

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As a typical discontinuous medium, discrete granular materials’ creep behavior plays a crucial role in the formation and evolution of geological disasters such as landslides and debris flows. However, systematic research on the interaction mechanism between particle size and deviatoric stress and its impact on creep behavior remains insufficient. To reveal the coupled effects of particle size and deviatoric stress on creep behavior, this study conducted indoor creep tests on silica spherical particles under multiple conditions and systematically analyzed the influence patterns of different particle sizes and deviatoric stresses on the creep characteristics of granular materials. Based on the Derec creep model and experimental results, this study constructed a quantitative computational model of the creep state of granular materials and clarified the regulatory mechanism of particle size on the creep parameters of the system. The results indicate that the creep behavior of granular systems essentially reflects the dynamic balance between internal deformation and resistance to deformation within the particles. Creep parameters significantly influence system creep characteristics by regulating particle slip and creep behavior. Specifically, as particle size increases, the creep value of the system increases markedly, making it more prone to entering a liquid-like flow state. Concurrently, the system’s resistance to deformation declines while exhibiting heightened sensiti-vity to deviatoric stress. Furthermore, an increase in particle size not only significantly enhances the fluidity of the particle system but also amplifies its sensitivity to changes in deviatoric stress. Particles with larger diameters show a more pronounced response under high deviatoric stress conditions, and the flow characteristics of granular mate-rials are more susceptible to particle size variations. This influence manifests as a positive correlation between particle size and both the system's initial state parameters and characteristic strain, while exhibiting negative correlations with viscosity coefficient, critical creep velocity, and critical creep stress.

Strength-Deformation Behavior and Engineering Applications of Residual Soil Under Drying-Wetting Cycles and Construction Vibration

CHEN Dongxia, TANG Jiarun, WANG Dongdong, CHEN Bo, ZHANG Jingyi

2025, 53(10):  86-96.  doi:10.12141/j.issn.1000-565X.240593

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Under the coupled effects of drying-wetting cycles and construction vibration, both strength and deformation parameters of residual soil undergo significant degradation, thereby compromising the safety of excavation support systems. Through direct shear tests and consolidation tests, this study characterizes the strength-deformation behavior of residual soil under drying-wetting cycles and construction vibration, develops predictive models for deteriorated parameters, and implements them in high-fidelity numerical simulations of a metro excavation project. The experimental results indicate that: cohesion c undergoes nonlinear decay with increasing drying-wetting cycles n and vibration duration t; internal friction angle φ exhibits oscillatory increase with n, while vibration effects on φ diminish progressively at higher n; without vibration, compression coefficient a_v1-2 increases linearly with n, whereas reference tangent modulus E_{\mathrm{o}\mathrm{e}\mathrm{d}}^{\mathrm{r}\mathrm{e}\mathrm{f}} decreases gradually; under vibration, a_v1-2 shows triphasic evolution: rapid initial decrease slow secondary decrease eventual increase. By considering the effects of drying-wetting cycle and construction vibration, the excavation is divided into 6 impact zones: fully drying-wetting-affected, over drying-wetting-affected, strongly coupled drying-wetting and vibration, weakly coupled drying-wetting-affected, vibration-only, and unaffected. Degraded soil parameters corresponding to each impact zone were implemented in high-fidelity numerical simulations of the excavation sequence. Results reveal that surface settlement first decreases then increases with horizontal distance from the excavation edge. As the excavation depth increases, diaphragm wall horizontal displacement exhibits a “small-large-small” profile along the wall height. Both ground settlement and wall horizontal displacement are consistently smaller on the side adjacent to an existing building than on the unobstructed side. Incorporating the coupled effects of drying and wetting cycling and construction vibration, the simulated surface settlements and wall horizontal displacements match the field measurements more closely, thus providing a practical guidance for the design and construction of the residual soil excavations.

Tooth Flank Optimization Design of Hypoid Gear with Low Installation Error Sensitivity

JI Shuting, ZHAI Zixuan, ZHANG Yueming, YUAN Erhao, BIAN Xinyi, ZHANG Qing

2025, 53(10):  97-108.  doi:10.12141/j.issn.1000-565X.250079

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Regarding problems such as the contact characteristics being extremely sensitive to installation error and generating vibration and noise caused by improper parameters design of hypoid gears, this paper proposed an optimized design method for gear aimed at reducing sensitivity to installation error. Firstly, it proposed a tooth flank contact characteristics evaluation model considering the installation error, including the variation of contact area, the offset of contact trace center value, and the variation of the conversion point amplitude of the transmission error curve. Then, it proposed a NURBS surface fitting method with reduced parameters and carried out tooth flank contact analysis. The mapping relationships among the installation error, the preset control parameters of tooth flank, the machining parameters of tooth flank and the contact characteristic parameters were established. Continuing, this study elucidated the influence patterns of installation error on tooth flank contact characteristics. It established a comprehensive sensitivity model for individual contact characteristic parameter relative to installation error. Finally, with the lowest sensitivity as the optimization goal, the genetic algorithm was used to optimize the design of the preset parameters of the tooth flank. Taking two typical operation condition as an example, through the comparative analysis of the meshing characteristics before and after optimization, it is found that the sensitivity of the optimized tooth flank contact area, the center point coordinates of the contact trace and the variation of the transmission error to the installation error are reduced. The tooth flank optimization design method proposed in this paper can effectively solve the problem that the tooth flank contact characteristics are extremely sensitive to the installation error, and reduce the vibration and noise in the transmission.

Nonlinear Dynamic Analysis of Ravigneaux Planetary Gear Transmission System

MO Shuai, HUANG Taojiang, HU Yongjun, CHEN Sujiao, SHI Wenai, ZHANG Wei

2025, 53(10):  109-117.  doi:10.12141/j.issn.1000-565X.250046

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To enhance the transmission stability during vehicle gearbox operation, this paper analyzed the nonlinear vibration characteristics of the Ravigneaux planetary gear transmission system in the transmission, and established a dynamic model of the Ravigneaux planetary gear transmission system including a variety of nonlinear factors. The model comprehensively considers nonlinear factors such as time-varying meshing stiffness, time-varying meshing damping, comprehensive transmission error, dynamic meshing force and time-varying friction force. Based on Newton’s second law, the nonlinear dynamic differential equations of the system were derived, and the Runge-Kutta numerical integration method was used to iteratively solve the differential equations of the system to obtain the dynamic response characteristics of the system under different external excitation frequencies. To investigate the impact of different excitation frequencies on the vibration displacement of the front and rear sun gear pairs, this study constructed time history diagrams, frequency spectra, phase portraits, and Poincare maps. The analysis shows that the vibration displacement evolution law of the two gear pairs is consistent. In order to further reveal the evolution law of the nonlinear response of the system, the bifurcation diagram and the spatial waterfall diagram were used to analyze the influence of the external excitation frequency on the nonlinear behavior of the system and reveal its evolution process. The results show that vibration displacement of the dual gear pairs undergoes a nonlinear evolution path along with variations in external excitation frequency: transitioning from chaotic motion through period-doubling bifurcation, and ultimately converging to periodic motion. By reasonably adjusting the external excitation frequency, unsteady vibrations can be effectively suppressed throughout the system, transient impact loads reduced, thereby enhancing operational stability and extending gear transmission service life. This research provides both theoretical foundations and engineering references for designing and optimizing high-performance, highly-reliable transmissions for new energy vehicles.

Wear Model of RV Reducer Based on Mixed Lubrication Analysis

NI Wencheng, LI Linling, ZHAO Zhijun, WU Qiong, LI Junyang, CHENG Gong

2025, 53(10):  118-130.  doi:10.12141/j.issn.1000-565X.240505

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Compared with traditional planetary gear reducers and harmonic drive reducers, the rotary vector (RV) reducer features higher power density and is widely used in fields such as aerospace and aviation special equipment, industrial robots, high-end CNC machine tools, etc. However, in special and extreme environments, particularly under severe operating conditions involving high/low temperatures, heavy loads, and high speeds, the components within RV reducers demand exceptionally high machining precision. Micron-level errors can cause multi-tooth meshing under load to evolve into multi-tooth interference. This compromises lubrication between components, ultimately leading to wear-induced failure. However, current research on the wear behavior of RV reducers under special extreme working conditions remains inadequate, and no effective wear prediction model has been established. Based on tribology theory and gear meshing principles, this study first conducted kinematic and force analyses of key components to determine the contact geometry, velocities, and loads of tribo-pairs. Subsequently, macroscopic contact geometry, microscopic surface topography, velocities, and loads were incorporated into the Reynolds equation and film thickness equation to establish a mixed lubrication analysis model for RV reducer components. Based on this, it solved the hybrid lubrication model for different components to obtain the interfacial film thickness of parts, thereby determining that the cycloidal-pin wheel and needle bearing exhibit the poorest lubrication state among RV reducer components and represent the most vulnerable weak links prone to wear failure. Using wear failure of these vulnerable components as the reducer’s wear failure criterion, an RV reducer wear model based on the hybrid lubrication model was established. Finally, equivalent friction-wear experiments were conducted to calibrate the wear model using experimental data. The ultimately established wear model enables prediction of RV reducer wear under special extreme working conditions, providing theoretical support for enhancing its service performance.

History, Present Situation and Prospect of Research on Leg Configuration of Humanoid Robot

DING Hongyu, SHI Zhaoyao, ZHANG Pan, FU Chunjiang

2025, 53(10):  131-144.  doi:10.12141/j.issn.1000-565X.240228

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The motion performance of humanoid robots has not yet fully reached the level of human beings, which is one of the factors hindering their large-scale industrial application. This limitation stems not only from constraints in control algorithms but also from mechanical structure design, particularly the leg configuration, which largely determines a robot’s dynamic balance, load capacity, and energy efficiency. The study examined the origins and evolution of leg configurations in humanoid robots, both domestically and internationally. Currently, the leg configurations of humanoid robots are primarily categorized into three types: serial, parallel, and hybrid serial-parallel. Their structural characteristics directly influence locomotion performance. The study compared the serial, the parallel and the series-parallel configurations and their performance characteristics. The serial configuration offers a large workspace and high flexibility, but its relatively lower stiffness—due to the extended joint transmission chain—compromises its load capacity. The parallel configuration provides high rigidity and fast dynamic response, yet its range of motion is limited. The hybrid serial-parallel design combines the strengths of both, achieving ba-lanced stiffness and flexibility, which has increasingly made it a key research focus in recent years. Finally, this paper also discussed technical difficulties and hot spots in the study of leg configuration and pointed out the development trend: the leg configuration is developing from single series configuration to parallel and series-parallel configuration, from rigid actuator to elastic actuator and quasi direct drive actuator, from torque control to hybrid force-position control.

Food Science & Technology

Synergistic Effect and Mechanism of Phloretin and Lauraldehyde on the Killing of Alicyclobacillus acidoterrestris Spores

XIAO Xinglong, ZHANG Ziqiang, CHEN Juntai, XIE Jialin, CAO Yifang

2025, 53(10):  145-154.  doi:10.12141/j.issn.1000-565X.240526

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To address the challenge of Alicyclobacillus acidoterrestris spore contamination of fruit juice, this study aimed to screen and evaluate the bactericidal effect of a synergistic combination of plant-derived actives and their mechanism of action. The study determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of plant-derived active compounds. By calculating the fractional inhibitory concentration index (FICI), a synergistic combination against Alicyclobacillus acidoterrestris spores was identified: phloretin (Ph) and lauric aldehyde (La). The results show that the MIC of phloretin is 0.1 mg/mL, and MBC is more than 6.4 mg/mL; the MIC of lauraldehyde is 0.4 mg/mL, and MBC is more than 6.4 mg/mL; the FICI of the combined effect of the two substances is 0.5. The 8PL (2 MIC_Ph + 2 MICLa) synergistic combination shows the best spore-killing effect in the synergistic combinations, and in the culture medium, the number of spores decreases by 10^6.1 CFU/mL after 2 days of treatment in the 8PL synergistic combination; inoculating 10⁴ CFU/mL of Alicyclobacillus acidoterrestris spores in apple juice, the 8PL synergistic combination treatment can reduce the spores to 0 after 1 day and maintain the effect for at least 14 days. For apple juice samples with an inoculation amount of 10⁶ CFU/mL, the 8PL synergistic combination treatment requires more than 3 days to reduce spores to 0 CFU/mL, but after 14 days, 10^2.2 CFU/mL spores are detected again. As the concentration of synergistic combination increases, the spore absorbance significantly decreases and the fluorescence spectrum increases. By scanning electron microscopy, irregular wrinkles on the surface of the spores disappear, and the surface gradually becomes smooth with an increase in the degree of depression and fragmentation. Transmission electron microscopy (TEM) observations revealed spore membrane disruption, accompanied by progressively increasing leakage of nucleic acids and proteins. The above results indicate that the synergistic combination will cause certain damage to structures such as spore membranes. In addition, the release of pyridine dicarboxylic acid (DPA) also significantly increases, greatly reducing the stress resistance of spores. In summary, the synergistic combination of phloretin and lauraldehyde has a good killing effect on Alicyclobacillus acidoterrestris spores, and it is an effective strategy for fruit juice antibacterial and preservative properties.

Effects of Bupropion Hydrochloride on Resistome of Gut Microbiota in SD Rats

YAN He, CHEN Chunxia, LIU Zongbao, LI Jialin, ZHAN Shimin

2025, 53(10):  155-173.  doi:10.12141/j.issn.1000-565X.240258

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To investigate the impact of the antidepressant bupropion hydrochloride on the gut microbiome resistome, this study employed Sprague-Dawley (SD) rats as model organisms. Using both 16S rRNA amplicon sequencing and metagenomic sequencing approaches, it systematically analyzed the drug’s effects on microbial communities and their resistome profiles in both fecal and cecal contents. Furthermore, it conducted comprehensive correlation analyses to elucidate potential relationships between these alterations. The results show that prevalent types of ARGs in the feces and cecum samples include bacitracin, tetracycline, vancomycin, and macrolides-lincomycin-streptogramin (MLS). Compared to the control group (HC), the bupropion hydrochloride gavage intervention group (Bup-PO) shows increased total abundance of bacterial antibiotic resistance genes (ARGs) in both fecal and cecal content samples, with statistically significant differences observed only in fecal samples. In terms of ARG types, the Bup-PO group demonstrates significantly increased relative abundance of six antibiotic resistance gene classes in fecal samples compared to the HC group, including: aminoglycoside resistance genes, bacitracin resistance genes, mupirocin resistance genes, rifamycin resistance genes, tetracycline resistance genes, Vancomycin resistance genes. Notably, the treatment group also shows an expansion in the diversity of vancomycin resistance gene variants. In cecum samples, the Bup-PO group significantly increases the relative abundance of 3 resistance gene types, tetracycline, daunorubicin, and fosfomycin. On ARG subtypes, in fecal samples, compared to the HC group, the Bup-PO group significantly increases the relative abundance of vancomycin (vanAG, vanRI, vanSA, vanSI), tetracycline (tetM, tetO, tet32), bacitracin (bceA, bcrA) and rifampicin (rpoB) resistance genes. In cecum samples, the effect of gavage bupropion on ARGs differs from that in fecal samples, with gavage intervention of bupropion causing fluctuations in the relative abundance of the MLS class of resistance genes, decreasing the abundance of lmrB but increasing the abundance of macB. Concurrently, bupropion hydrochloride intervention via oral gavage significantly increased the relative abundance of tetracycline (tetW) and daunorubicin (drrA) resistance genes. The above results suggest that bupropion intervention has the risk of increasing antibiotic resistance in rat’s gut microbiota. UCG-005 and norank__f__norank__o_Clostridia_UCG-014 are the major bacterial genera of the rat intestinal flora, and correlation analyses suggest that UCG-005 may be a potential host for tetracycline, rifampicin, mupirocin, and bacitracin, vancomycin resistance genes, while norank_f__norank__o_Clostridia_UCG-014 may be a potential bacterial host for daunorubicin resistance genes, and their increase after bupropion intervention may be responsible for the increased abundance of these six types of resistance genes.

Purification of Total Flavonoids from Gnaphalium affine and Analysis on Its Antioxidant Stress Activity

ZHENG Bisheng, XU Yanting, XU Qiuxiong, FAN Xinlühui

2025, 53(10):  174-182.  doi:10.12141/j.issn.1000-565X.250082

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Gnaphalium affine is rich in flavonoids with diverse biological activities, but research on its protective effects against cellular oxidative damage remains limited. To further explore its utilization value, this study aimed to optimize the purification process of total flavonoids from Gnaphalium affine, investigate its chemical composition, and deeply explore its protective mechanism against oxidative stress damage. In this study, Gnaphalium affine was used as the raw material. After deep eutectic solvent heating extraction, the optimal macroporous adsorption resin was screened and the purification process was determined. LC-MS/MS was employed for qualitative and quantitative analysis of the purified total flavonoids to clarify their chemical composition. An oxidative stress model induced by H₂O₂ in HepG2 cells was used to investigate the protective effects of the purified Gnaphalium affine total flavonoids against cellular oxidative damage. The results show that, through screening, D101 is the most suitable resin for purifying Gnaphalium affine flavonoids, with 60% ethanol solution as the desorption solvent. Dynamic adsorption-desorption experiments determined the optimal sample loading volume and eluent volume to be 124 mL and 200 mL, respectively. Eleven flavonoid compounds were isolated and identified from the total flavonoids of Gnaphalium affine, primarily including luteolin, hyperin, quercetin, apigenin, and scutellarin, etc. Among these, hyperoside is the most abundant, with a content of (391.91 ± 40.69) μg/g. Purified total flavonoids from Gnaphalium affine can significantly increase cell viability after H₂O₂-induced oxidative damage, effectively scavenge excess reactive oxygen species (ROS), and reduce lactate dehydrogenase (LDH) release from damaged cells. Concurrently, they enhanced the activities of superoxide dismutase (SOD) and catalase (CAT), as well as glutathione (GSH) levels. Real-time quantitative polymerase chain reaction (qPCR) results indicate that Gnaphalium affine total flavonoids can mitigate oxidative stress by regulating the Keap1/Nrf2 signaling pathway. These findings demonstrate that Gnaphalium affine total flavonoids possess strong antioxidant activity, providing a reference for the development of related products.