Research on fault diagnosis of rolling bearing based on improved convolutional neural network with sparrow search algorithm.

Traditional approaches to the intelligent fault diagnosis of rolling bearings have predominantly relied on manual expertise for feature extraction, a practice that compromises robustness. In addition, the existing convolutional neural network (CNN) is characterized by an overabundance of parameters and a substantial requirement for training samples. To address these limitations, this study introduces a novel fault diagnosis algorithm for rolling bearings, integrating a one-dimensional convolutional neural network (1DCNN) with a support vector machine (SVM) to form an enhanced 1DCNN-SVM model. This model is further refined using the sparrow search algorithm (SSA) for the optimal adjustment of the parameters of 1DCNN-SVM. Specifically, by substituting the CNN's final softmax layer with an SVM, the model becomes better suited for processing limited data volumes. In addition, the incorporation of batch normalization and dropout layers within the CNN framework significantly augments its fault classification accuracy for rolling bearings, concurrently mitigating the risk of overfitting. The SSA is subsequently applied to refine three principal hyper-parameters: batch size, initial learning rate, and the L2 regularization coefficient, thereby overcoming the challenges associated with manually adjusting parameters, such as extended processing times and unpredictable outcomes. Empirical tests on Case Western Reserve University (CWRU) datasets revealed the model's superior performance, with the SSA-optimized 1DCNN-SVM showcasing diagnostic accuracies over 98%, marked improvements over conventional models, and a significant reduction in processing times. This method not only marks a significant advancement in intelligent fault diagnosis for rolling bearings but also demonstrates the potential of integrating machine learning for more precise and efficient diagnostics. The SSA-1DCNN-SVM model, optimized for accuracy and minimal data use, sets a new standard in fault diagnosis, relevant for machinery health monitoring and maintenance strategies across various industries.

Serum Folate and Vitamin B12 Modify the Associations of N6AMT1 Genetic Variants with Gestational Diabetes Mellitus: A Cross-Sectional Study in Chinese Pregnant Women.

Purpose: This study aimed to explore the association between N-6 adenine-specific DNA methyltransferase 1 (N6AMT1) single nucleotide polymorphisms (SNPs) and gestational diabetes mellitus (GDM) and the modification of the relationship by folate and vitamin B12. Methods: A cross-sectional study involving 1303 pregnant women (262 GDM and 1041 non-GDM) was performed in Tianjin, China. Nine SNPs in N6AMT1 were genotyped, and serum folate, vitamin B12, and homocysteine (Hcy) levels were measured. The logistic regression models determined the odds ratios (ORs) for SNPs in N6AMT1 and the gene-nutrition interactions on GDM. Results: N6AMT1 rs7282280, rs1048546, and rs1997605 were related to GDM under the dominant model after adjusting for multiple covariates. Individuals carrying the N6AMT1 rs7282280 TC/TT genotypes had a lower risk of developing GDM, regardless of serum folate and vitamin B12 levels. However, rs1048546 TG/GG genotypes were associated with lower GDM risk when serum folate ≥ 6.0 ng/mL. Pregnancies with the risk genotypes in N6AMT1 and higher serum folate or lower vitamin B12 are more prone to GDM. The study also showed a statistically significant additive interaction between N6AMT1 rs1997605 GG genotypes and lower vitamin B12 (RERI: 2.54; 95% CI: 0.17, 4.92). Conclusion: SNPs in N6AMT1 were found to be associated with GDM, and serum folate and vitamin B12 levels can modify their associations.

A Hydrogel Electrolyte with High Adaptability over a Wide Temperature Range and Mechanical Stress for Long-Life Flexible Zinc-Ion Batteries.

Flexible zinc-ion batteries have garnered significant attention in the realm of wearable technology. However, the instability of hydrogel electrolytes in a wide-temperature range and uncontrollable side reactions of the Zn electrode have become the main problems for practical applications. Herein, N,N-dimethylformamide (DMF) to design a binary solvent (H2 O-DMF) is introduced and combined it with polyacrylamide (PAM) and ZnSO4 to synthesize a hydrogel electrolyte (denoted as PZD). The synergistic effect of DMF and PAM not only guides Zn2+ deposition on Zn(002) crystal plane and isolates H2 O from the Zn anode, but also breaks the hydrogen bonding network between water to improve the wide-temperature range stability of hydrogel electrolytes. Consequently, the symmetric cell utilizing PZD can stably cycle over 5600 h at 0.5 mA cm- 2 @0.5 mAh cm-2 . Furthermore, the Zn//PZD//MnO2 full cell exhibits favorable wide-temperature range adaptability (for 16000 cycles at 3 A g-1 under 25 °C, 750 cycles with 98 mAh g-1 at 0.1 A g-1 under -20 °C) and outstanding mechanical properties (for lighting up the LEDs under conditions of pressure, bending, cutting, and puncture). This work proposes a useful modification for designing a high-performance hydrogel electrolyte, which provides a reference for investigating the practical flexible aqueous batteries.

Non-adiabatic conformation distortion charge transfer enables dual emission of thermally activated delayed fluorescence and room temperature phosphorescence.

In this work, we report for the first time that thiophenol-substituted naphthalimide can achieve thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) simultaneously through non-conjugated flexible connection. Herein, we explain that the enhancement of intersystem crossing (ISC) between the singlet excited state and triplet excited states in NISPh is mainly caused by the non-adiabatic conformation distortion charge transfer (CDCT) of the excited states. More precisely, CDCT results in the conformation matching and energy barrier decrease between the excited states. In addition, the electronic and vibration coupling is further enhanced in NISPh. Our work substantiates a rational design strategy for the development of simple purely organic materials to achieve dual emission of TADF and RTP.

Aqueous-phase dual-functional chiral perovskites for hydrogen sulfide (H2S) detection and antibacterial applications in Escherichia coli.

Perovskite nanocrystals (PNCs) have attracted extensive attention for their potential applications in biology. However, only a handful of PNCs have been scrutinized in the biological domain due to issues such as instability, poor dispersion, and size inhomogeneity in polar solvents. The development of dual-functional perovskite nanomaterials with hydrogen sulfide (H2S) sensing and antibacterial capabilities is particularly intriguing. In this study, we prepared chiral quasi-two-dimensional (quasi-2D) perovskite nanomaterials, Bio(S-PEA)2CsPb2Br7 and Bio(R-PEA)2CsPb2Br7, that were uniformly dispersed in aqueous media. The effective encapsulation of methoxypolyethylene glycol amine (mPEG-NH2) improved water stability and uniformity of particle size. Circular dichroism (CD) signals were created by the successful insertion of chiral cations. These perovskites as probes showed a rapid and sensitive fluorescence quenching response to H2S, and the effect of imaging detection was observed at the Escherichia coli (E. coli) level. As antibacterial agents, their pronounced positive charge properties facilitated membrane lysis and subsequent E. coli death, indicating a significant antibacterial effect. This work has preliminary explored the application of chiral perovskites in biology and provides insight into the development of bifunctional perovskite nanomaterials for biological applications.

Mechanism of SO2/H2O enhanced rare earth tailings catalysts in NH3-SCR at medium and high temperature.

Rare earth tailings (RET) NH3-SCR catalysts were prepared by mechanical and microwave activation of a large amount of rare earth tailings after beneficiation of Bayan Ebo rare earth ore. The effects of SO2/H2O on the denitrification performance of the RET catalysts were evaluated by conducting denitrification activity tests, SO2/H2O tolerance tests and in situ DRIFTs mechanistic analysis. The results showed that the denitrification activity was significantly increased in the presence of SO2/H2O. And in situ DRIFTs analysis showed that in the presence of SO2/H2O, SO2 could be adsorbed as SO32- groups by the hydroxyl groups on the catalyst surface and react with SO42- to form S2O72- species. And in the presence of NH3, S2O72- would decompose into unstable SO42- species and SO32- and continue to react cyclically to form S2O72- species, providing the RET catalyst provides more acid sites, facilitating the SCR reaction.

Sahara's surface transformation forced an abrupt hydroclimate decline and Neolithic culture transition in northern China.

The remote forcing from land surface changes in the Sahara is hypothesized to play a pivotal role in modulating the intensity of the East Asian summer monsoon (EASM) through ocean-atmospheric teleconnections. This modulation has far-reaching consequences, particularly in facilitating societal shifts documented in northern China. Here, we present a well-dated lake-level record from the Daihai Lake Basin in northern China, providing quantitative assessments of Holocene monsoonal precipitation and the consequent migrations of the northern boundary of the EASM. Our reconstruction, informed by a water-and-energy balance model, indicates that annual precipitation reached ∼700 mm during 8-5 ka, followed by a rapid decline to ∼550 mm between 5 and 4 ka. This shift coherently aligns with a significant ∼300 km northwestward movement of the EASM northern boundary during the Middle Holocene (MH), in contrast to its current position. Our findings underscore that these changes cannot be entirely attributed to orbital forcing, as corroborated by simulation tests. Climate model simulations deployed in our study suggest that the presence of the Green Sahara during the MH significantly strengthened the EASM and led to a northward shift of the monsoon rainfall belt. Conversely, the Sahara's reversion to a desert landscape in the late Holocene was accompanied by a corresponding southward retraction of monsoon influence. These dramatic hydroclimate changes during ∼5-4 ka likely triggered or at least contributed to a shift in Neolithic cultures and societal transformation in northern China. With decreasing agricultural productivity, communities transitioned from millet farming to a mixed rainfed agriculture and animal husbandry system. Thus, our findings elucidate not only the variability of the EASM but also the profound implications of a remote forcing, such as surface transformations of the Sahara, on climatic changes and cultural evolution in northern China.

Transcriptomic analysis identifies diagnostic genes in polycystic ovary syndrome and periodontitis.

PURPOSE: To investigate underlying co-mechanisms of PCOS and periodontitis through transcriptomic approach. METHODS: PCOS and periodontitis gene expression data were downloaded from the GEO database to identify differentially expressed genes. GO and KEGG pathway enrichment analysis and random forest algorithm were used to screen hub genes. GSEA analyzed the functions of hub genes. Correlations between hub genes and immune infiltration in two diseases were examined, constructing a TF-ceRNA regulatory network. Clinical samples were gathered from PCOS and periodontitis patients and RT-qPCR was performed to verify the connection. RESULTS: There were 1661 DEGs in PCOS and 701 DEGs in periodontitis. 66 intersected genes were involved and were enriched in immune and inflammation-related biological pathways. 40 common genes were selected from the PPI network. RF algorithm demonstrated that ACSL5, NLRP12, CCRL2, and CEACAM3 were hub genes, and GSEA results revealed their close relationship with antigen processing and presentation, and chemokine signaling pathway. RT-qPCR results confirmed the upregulated gene expression in both PCOS and periodontitis. CONCLUSION: The 4 hub genes ACSL5, NLRP12, CCRL2, and CEACAM3 may be diagnostic genes for PCOS and periodontitis. The created ceRNA network could provide a molecular basis for future studies on the association between PCOS and periodontitis.

The determination of underivatized chlormequat, fosetyl-aluminium and phosphonic acid residues in maize and soybean by LC-MS/MS.

In this study, a simple, rapid and sensitive method was developed for the simultaneous determination of chlormequat, fosetyl-aluminium and phosphonic acid residues in maize and soybean using liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). Analytes were extracted with acetic acid solution, purified on an HLB column, and then filtered through a 0.2 µm hydrophilic microporous filter membrane. They were then separated on an IC column using a separation phase consisting of polyvinyl alcohol particles with quaternary ammonium groups. The mobile phase optimised with water was denoted as mobile phase A and that optimised with 200 mmol L-1 ammonium bicarbonate solution containing 0.05% ammonium hydroxide was denoted as mobile phase B. The residues were detected by tandem mass spectrometry with negative electrospray ionization in a multi-reaction monitoring mode. The correlation coefficient (R ≥ 0.997) showed good linear regressions for all analytes in water as well as in maize and soybean matrices with a wide dynamic range of 0.001 to 0.5 mg L-1 for calibration. The mean recoveries (RSDs) of the analytes were in the range 85.0-106.4% (5.5-14.9%), 81.7-109.5% (2.7-11.0%) and 74.7-104.4% (2.9-6.1%) at three concentration levels (0.05, 0.1 and 1 mg kg-1) for the interday test (n = 15). The limit of quantification (LOQ) and detection (LOD) of the method for different matrices were 0.01 and 0.003 mg kg-1, respectively. In conclusion, the established analytical approach has high sensitivity and good accuracy and precision and is suitable for monitoring chlormequat, fosetyl-aluminium and phosphonic acid residues in maize and soybean.

Increased Impact of Aviation on Air Quality and Human Health in China.

China's civil aviation market has rapidly expanded, becoming the world's second-largest. However, the air quality and health impacts caused by its aircraft emissions have been inadequately assessed. Here, we leverage an updated emission inventory of air pollutants with improved temporal and spatial resolution based on hundreds of thousands of flight trajectories and simulate aviation-attributable contributions to ground-level air pollution in China. We find that in 2017, the annual-average aviation-attributed PM2.5 and O3 concentrations were 0.4-1.5 and 10.6-14.5 µg·m-3, respectively, suggesting that aviation emissions have become an increasingly important source of ambient air pollution. The contributions attributable to high-altitude emissions (climb/cruise/descent) were comparable to those at low altitudes (landing and takeoff). Aviation-attributed ambient PM2.5 and O3 exposures are estimated to have caused about 67,000 deaths in China in 2017, with populous coastal regions in Eastern China suffering the most due to the dense aviation activity. We recommend that industrial and policy stakeholders expedite an agenda of regulating air pollutants harmonized with decarbonization efforts for a more sustainable aviation future.

Amino acid 17 in QRDR of Gyrase A plays a key role in fluoroquinolones susceptibility in mycobacteria.

IMPORTANCE: Fluoroquinolones (FQs) play a key role in the treatment regimens against tuberculosis and non-tuberculous mycobacterial infections. However, there are significant differences in the sensitivities of different mycobacteria to FQs. In this study, we proved that this is associated with the polymorphism at amino acid 17 of quinolone resistance-determining region of Gyrase A by gene editing. This is the first study using CRISPR-associated recombination for gene editing in Mycobacterium abscessus to underscore the contribution of the amino acid substitutions in GyrA to FQ susceptibilities in mycobacteria.

A sandwiched ventricular explant assay to model mouse coronary angiogenesis ex vivo.

Developing an ex vivo system that mimics in vivo developmental coronary angiogenesis provides an improved understanding of its underlying molecular and cellular mechanisms. Here, we present a sandwiched embryonic ventricular explant assay to model mouse coronary angiogenesis ex vivo. We describe steps for breeding mice, labeling endocardial cells, isolating murine hearts, dissecting left ventricles, and making sandwiched explants in Matrigel. We then detail procedures for modeling coronary angiogenesis and taking images. For complete details on the use and execution of this protocol, please refer to Lu et al. (2023)1.

Efficacy of concentrated growth factor (CGF) in the surgical treatment of oral diseases: a systematic review and meta-analysis.

BACKGROUND: Concentrated growth factor (CGF), a new autologous platelet concentrate, has been widely investigated to the adjunctive treatment of oral diseases. This study aims to evaluate the efficacy of CGF in the surgical treatment of oral diseases. METHODS: MEDLINE, Web of Science, Scopus, Cochrane, and EMBASE databases were searched up to July 2023. Only randomized clinical trials were included. The methodologic quality was evaluated by the Cochrane Risk of Bias Tool. RevMan 5.4 software was used for data analysis. RESULTS: In the treatment of periodontal intrabony defects, bone graft combined with CGF was significantly superior to bone graft (P < 0.01), with mean intrabony defect depth reduction of 1.41 mm and mean clinical attachment level gain of 0.55 mm. In the regenerative surgery of furcation defects, the effect of CGF group was significantly better than control group (P < 0.0001), with mean probing depth reduction of 0.99 mm, vertical bone gain of 0.25 mm, and horizontal bone gain of 0.34 mm. CGF combined with coronally advanced flap (CAF) was more effective than CAF alone (mean keratinized tissue width increase of 0.41 mm, mean gingival thickness increase of 0.26 mm, P < 0.00001), but less effective than connective tissue graft (CTG) combined with CAF (mean root coverage difference of -15.1%, mean gingival thickness difference of -0.5 mm, P < 0.0001). In the alveolar ridge preservation, additional use of CGF reduced horizontal bone resorption by 1.41 mm and buccal vertical bone resorption by 1.01 mm compared to control group (P < 0.0001). The VAS score of CGF group was significantly lower than that of the control group at the 1st and 7th day after oral surgery (P < 0.0001). CONCLUSIONS: CGF can exert a positive adjunctive effect for the regenerative surgery of periodontal intrabony defects, furcation defects, and alveolar ridge preservation procedure. CGF combined with CAF has a better therapeutic effect on gingival recession compared to CAF alone, although it is not as effective as CTG combined with CAF. CGF could promote postoperative healing and pain relief in oral surgery within a week. There is currently not enough evidence to support the clinical benefits of CGF in other oral surgeries.

Fe2O3 micron particles are critical for electron transfer and the distribution of electrochemically active bacteria in soil MFCs.

Fe2O3 plays a complex role in soil electron transfer. A microbial fuel cell (MFC) was constructed to drive the directional transfer of electrons in soil, and the results revealed that Fe2O3 acts first as a capacitor, intercepting and reserving the electrons produced by electrochemically active bacteria (EAB) in the soil, which leads to a decrease in hexachlorobenzene (HCB) removal efficiency with increasing proportions of Fe2O3 dosing (R2 = 0.85). The Fe2O3 then exerted its semiconductor properties in synergy with dissolved Fe2+ as an electron mediator to promote the flow of electrons in the soil. Power generation by the MFC was significantly and positively correlated with the concentration of dissolved Fe2+ (r = 0.51) and the Fe2O3 dosing proportion (r = 0.97). The higher HCB removal efficiency, spatial distribution of intercepted electrons, and abundance of electron transfer metabolic pathways confirmed that Fe2O3 promoted electron-flow fluxes in soil. Additionally, Geobacter sp., (direct electron transfer) and Pseudomonas sp., (indirect electron transfer) were the dominant electrochemically active bacteria in the anode and soil of MFC, respectively. In this study, both dissolved (Fe2+) and solid state (Fe2O3) electron mediators functioned as electron transporters in soil, we propose an internal "electron internet" of soil consisting of points and lines.

Soil physiochemical properties and bacterial community changes under long-term polycyclic aromatic hydrocarbon stress insitu steel plant soils.

In situ soils were collected at two depths in Jinan and Hangzhou steel plants, which both have a long history of operation and polycyclic aromatic hydrocarbons (PAHs) contamination. The richness of 16 S rRNA gene and bacterial community of the soil were determined by real-time PCR and high-throughput sequencing. Soil physicochemical properties, PAHs contamination characteristics, and their interrelationships were also analyzed. In general, the PAHs contamination decreased with increasing soil depths. The physicochemical properties and PAH concentration of soil had synergistic impacts on the composition of the bacterial community. The long-term higher PAHs stress in Hangzhou contaminated soil (982 mg kg-1) increased the bacterial abundance and diversity, while that of Jinan contaminated soil (63 mg kg-1) decreased bacterial abundance and diversity. The pH value, sand content of the soil were positively correlated (P < 0.05) with the bacterial diversity including Simpson, Shannon, Observed_species and Chao1 indexes., and the other soil properties exhibited negative correlations with different strengths. The abundances of Curvibacter, Pseudomonas, Thiobacillus, Lysobacter, and Limnobacter were positively correlated with the PAHs concentration (P < 0.01). Additionally, the network structure of the PAHs-contaminated soils was more complex compared to that of uncontaminated soils, with stronger linkages and correlations between the different bacteria. These findings provide a theoretical basis for microbial remediation of PAHs-polluted soil.

Formation of Size-Controllable Tetragonal Nanoprisms by Crystallization-Directed Ionic Self-Assembly of Anionic Porphyrin and PEO-Containing Triblock Cationic Copolymer.

The creation of anisotropic nanostructures with precise size control is desirable for new properties and functions, but it is challenging for ionic self-assembly (ISA) because of the non-directional electrostatic interactions. Herein, the formation of size-controllable tetragonal nanoprisms is reported via crystallization-directed ionic self-assembly (CDISA) through evaporating a micellar solution on solid substrates. First, ISA is designed with a crystalline polyethylene oxide (PEO) containing cationic polymer poly(2-(2-guanidinoethoxy)ethyl methacrylate)-b-poly(ethyleneoxide)-b-poly(2-(2-guanidinoethoxy)-ethylmethacrylate) (PGn -PEO230 -PGn ) and an anionic 5,10,15,20-Tetrakis(4-sulfonatophenyl) porphyrin (TPPS) to form micelles in aqueous solution. The PG segments binds excessive TPPS with amplenet chargeto form hydrophilic corona, while the PEO segments are unprecedentedly dehydrated and tightly packed into cores. Upon naturally drying the micellar solution on a silicon wafer, PEO crystallizationdirects the micelles to aggregate into square nanoplates, which are further connected to nanoprisms. Length and width of the nanoprisms can be facilely tuned by varying the initial concentration. In this hierarchical process, the aqueous self-assembly is prerequisite and the water evaporation rate is crucial for the formation of nanostructures, which provides multiple factors for morphology regulating. Such precise size-control strategy is highly expected to provide a new vision for the design of advanced materials with size controllable anisotropic nanostructures.

Crotonylation of GAPDH regulates human embryonic stem cell endodermal lineage differentiation and metabolic switch.

BACKGROUND: Post-translational modifications of proteins are crucial to the regulation of their activity and function. As a newly discovered acylation modification, crotonylation of non-histone proteins remains largely unexplored, particularly in human embryonic stem cells (hESCs). METHODS: We investigated the role of crotonylation in hESC differentiation by introduce crotonate into the culture medium of GFP tagged LTR7 primed H9 cell and extended pluripotent stem cell lines. RNA-seq assay was used to determine the hESC transcriptional features. Through morphological changes, qPCR of pluripotent and germ layer-specific gene markers and flow cytometry analysis, we determined that the induced crotonylation resulted in hESC differentiating into the endodermal lineage. We performed targeted metabolomic analysis and seahorse metabolic measurement to investigate the metabolism features after crotonate induction. Then high-resolution tandem mass spectrometry (LC-MS/MS) revealed the target proteins in hESCs. In addition, the role of crotonylated glycolytic enzymes (GAPDH and ENOA) was evaluated by in vitro crotonylation and enzymatic activity assays. Finally, we used knocked-down hESCs by shRNA, wild GAPDH and GAPDH mutants to explore potential role of GAPDH crotonylation in regulating human embryonic stem cell differentiation and metabolic switch. RESULT: We found that induced crotonylation in hESCs resulted in hESCs of different pluripotency states differentiating into the endodermal lineage. Increased protein crotonylation in hESCs was accompanied by transcriptomic shifts and decreased glycolysis. Large-scale crotonylation profiling of non-histone proteins revealed that metabolic enzymes were major targets of inducible crotonylation in hESCs. We further discovered GAPDH as a key glycolytic enzyme regulated by crotonylation during endodermal differentiation from hESCs. CONCLUSIONS: Crotonylation of GAPDH decreased its enzymatic activity thereby leading to reduced glycolysis during endodermal differentiation from hESCs.

Performance and mechanism of microbial fuel cell coupled with anaerobic membrane bioreactor system for fouling control.

To remove membrane fouling, a bio-electrochemical system that can generate a micro-electric field and micro-current was constructed. After 11 days of operation, the trans-membrane pressure difference of membrane modules in the open- and closed-circuit groups increased by 35.8 kPa and 6.2 kPa, respectively. The concentrations of total polysaccharide and protein in the open-circuit group were 1.8 and 1.1 times higher than those in the closed-circuit group, respectively. In addition, X-ray photoelectron spectroscopy and thermogravimetric analysis showed that inorganic crystals such as calcium carbonate were present on the membrane surface, and the concentration of calcium ion in the control group was 14.7 times that of the experimental group. High-throughput sequencing demonstrated that the enrichment of some electroactive bacteria and other microorganisms has a positive effect on the control of membrane fouling. Therefore, this system can effectively alleviate membrane fouling of a bioreactor, by targeting the membrane foulants.

Stimulation of atrazine degradation by activated carbon and cathodic effect in soil microbial fuel cell.

Soil microbial fuel cells (MFCs) have been increasingly studied in recent years and have attracted significant attention as an environmentally sustainable bioelectrochemical technology. However, the poor conductivity of the soil matrix and the neglect of the cathodic function have limited its application. In this study, quartz sand and activated carbon were subjected to investigation on their influence on atrazine degradation. Atrazine was introduced in different layers (cathode, upper layer) to explore the cathodic effect on atrazine removal. The results revealed that activated carbon could reduce the internal resistance (693 Ω) and generate the highest power density (25.51 mW/m2) of the soil MFCs, and thus increase the removal efficiency (97.92%) of atrazine. The dynamic degradation profiles of atrazine were different for different adding layers. The cathode electrode acted as an electron donor could increase the distance of the effective influence of the soil MFCs' cathode from the middle to the cathode layer. The cathode (region) and the region close to the cathode could degrade atrazine with the atrazine removal efficiencies ranging from 60.67% to 92.79%, and the degradation ability of the cathode was stronger than that of other layers. The degradation effect followed the order: cathode > upper > lower > middle). Geobacter, Desulfobulbus, and Desulfuromonas belonging to the δ-Proteobacteria class were identified as the dominant electroactive microorganisms in the anode layer, while their relative abundances are quite low in the upper and cathode layers. Pseudomonas is an atrazine-degrading bacterium, but its relative abundance was only 0.13-0.51%. Thus, bioelectrochemistry rather than microbial degradation was the primary driving force.