Investigation of spatiotemporal distribution and formation mechanisms of ozone pollution in eastern Chinese cities applying convolutional neural network.

Severe ground-level ozone (O3) pollution over major Chinese cities has become one of the most challenging problems, which have deleterious effects on human health and the sustainability of society. This study explored the spatiotemporal distribution characteristics of ground-level O3 and its precursors based on conventional pollutant and meteorological monitoring data in Zhejiang Province from 2016 to 2021. Then, a high-performance convolutional neural network (CNN) model was established by expanding the moment and the concentration variations to general factors. Finally, the response mechanism of O3 to the variation with crucial influencing factors is explored by controlling variables and interpolating target variables. The results indicated that the annual average MDA8-90th concentrations in Zhejiang Province are higher in the northern and lower in the southern. When the wind direction (WD) ranges from east to southwest and the wind speed (WS) ranges between 2 and 3 m/sec, higher O3 concentration prone to occur. At different temperatures (T), the O3 concentration showed a trend of first increasing and subsequently decreasing with increasing NO2 concentration, peaks at the NO2 concentration around 0.02 mg/m3. The sensitivity of NO2 to O3 formation is not easily affected by temperature, barometric pressure and dew point temperature. Additionally, there is a minimum [Formula: see text] at each temperature when the NO2 concentration is 0.03 mg/m3, and this minimum [Formula: see text] decreases with increasing temperature. The study explores the response mechanism of O3 with the change of driving variables, which can provide a scientific foundation and methodological support for the targeted management of O3 pollution.

The prevalence of scoliosis among adolescents in China: a systematic review and meta-analysis.

BACKGROUND: To systematically evaluate the prevalence of scoliosis in adolescents aged 10-18 years in China, and to provide evidence-based evidence for the early identification, prevention, and management of scoliosis in adolescents. METHODS: We searched 7 databases of CNKI, Wanfang, VIP, PubMed, Web of Science, Embase, and Cochrane Library from January 2000 to June 2024, and included related studies on scoliosis among Chinese adolescents aged 10-18. The quality evaluation criteria of cross-sectional studies recommended by the Agency for Healthcare Research and Quality (AHRQ) were used for literature quality evaluation. Stata 18.0 software was used for statistical analysis. RESULTS: We finally included 42 studies, involving a total of 1,149,330 subjects from 30 regions. The results showed that the prevalence of scoliosis in Chinese adolescents aged 10-18 years was 1.2% [95%CI (1.1%, 1.4%)]. The results of the subgroup analyses are as follows: ① The prevalence of scoliosis in adolescent women (1.6%) was higher than that in men (1.0%). ② The prevalence of scoliosis in adolescents aged 16-18 (1.3%) was higher than that in adolescents aged 10-15 (1.1%). ③ By region, the prevalence of scoliosis was slightly higher in the North (1.3%) than that in the South (1.2%). ④ According to the time of publication, the prevalence of scoliosis in Chinese adolescents increased from 0.9% during 2000-2015 to 1.6% during 2016-2024. ⑤ According to the degree of the Cobb angle, the curve magnitude was mainly mild (Cobb angle: 10°-19°), and the prevalence rate was 0.7%; the second was moderate (Cobb angle: 20°-39°), with a prevalence of 0.2%. CONCLUSION: The prevalence of scoliosis in adolescents aged 10-18 years in China is 1.2%, suggesting that the prevalence may be gradually increasing in recent years. In addition, the degree of scoliosis is mainly mild, and timely intervention and prevention are necessary.

Temporopolar blurring signifies abnormalities of white matter in mesial temporal lobe epilepsy.

OBJECTIVE: The single-center retrospective cohort study investigated underlying pathogenic mechanisms and clinical significance of patients with temporal lobe epilepsy and hippocampal sclerosis (TLE-HS), in the presence/absence of gray-white matter abnormalities (usually called "blurring"; GMB) in ipsilateral temporopolar region (TPR) on MRI. METHODS: The study involved 105 patients with unilateral TLE-HS (60 GMB+ and 45 GMB-) who underwent standard anterior temporal lobectomy, along with 61 healthy controls. Resected specimens were examined under light microscope. With combined T1-weighted and DTI data, we quantitatively compared large-scale morphometric features and exacted diffusion parameters of ipsilateral TPR-related superficial and deep white matter (WM) by atlas-based segmentation. Along-tract analysis was added to detect heterogeneous microstructural alterations at various points along deep WM tracts, which were categorized into inferior longitudinal fasciculus (ILF), uncinate fasciculus (UF), and temporal cingulum. RESULTS: Comparable seizure semiology and postoperative seizure outcome were found, while the GMB+ group had significantly higher rate of HS Type 1 and history of febrile seizures, contrasting with significantly lower proportion of interictal contralateral epileptiform discharges, HS Type 2, and increased wasteosomes in hippocampal specimens. Similar morphometric features but greater WM atrophy with more diffusion abnormalities of superficial WM was observed adjacent to ipsilateral TPR in the GMB+ group. Moreover, microstructural alterations resulting from temporopolar GMB were more localized in temporal cingulum while evenly and widely distributed along ILF and UF. INTERPRETATION: Temporopolar GMB could signify more severe and widespread microstructural damage of white matter rather than a focal cortical lesion in TLE-HS, affecting selection of surgical procedures.

Supervised, semisupervised, and unsupervised learning of the Domany-Kinzel model.

The Domany-Kinzel (DK) model encompasses several types of nonequilibrium phase transitions, depending on the selected parameters. We apply supervised, semisupervised, and unsupervised learning methods to studying the phase transitions and critical behaviors of the (1+1)-dimensional DK model. The supervised and the semisupervised learning methods permit the estimations of the critical points, the spatial and temporal correlation exponents, concerning labeled and unlabeled DK configurations, respectively. Furthermore, we also predict the critical points by employing principal component analysis and autoencoder. The PCA and autoencoder can produce results in good agreement with simulated stationary particle number density.

Identification of transcription factors associated with leaf senescence in tobacco.

Leaf senescence represents the final stage of leaf development, involving transcription factors (TFs)-mediated genetic reprogramming events. The timing of crop leaf senescence has a major influence on the yield and quality of crop in agricultural production. As important regulator of plant growth, the significance of TFs in the regulation of leaf senescence have been highlighted in various plant species by recent advances in genetics. However, studies on underlying molecular mechanisms are still not adequately explained. In this study, for analyzing the regulation of TFs on senescence of tobacco leaves, we combined gene differential expression analysis with weighted gene co-expression network analysis (WGCNA) to analyze the time-series gene expression profiles in senescing tobacco leaf. Among 3517 TF genes expressed in tobacco leaves, we identified 21, 35, and 183 TFs that were associated with early, middle, and late stages of tobacco leaf senescence, respectively. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation results reveal that these senescence response TFs are correlated with several biological pathways such as plant hormone signal transduction, ubiquitin mediated proteolysis and MAPK signaling pathway, indicating the roles of TFs in regulating leaf senescence. Our results provide implications for future studies of the potential regulatory mechanisms of TFs involved in senescence of tobacco leaves.

Integrated analysis of N6-methyladenosine- and 5-methylcytosine-related long non-coding RNAs for predicting prognosis in cervical cancer.

BACKGROUND: N6-methyladenosine (m6A) and 5-methylcytosine (m5C) play a role in modifying long non-coding RNAs (lncRNAs) implicated in tumorigenesis and progression. This study was performed to evaluate prognostic value of m6A- and m5C-related lncRNAs and develop an efficient model for prognosis prediction in cervical cancer (CC). METHODS: Using gene expression data of TCGA set, we identified m6A- and m5C-related lncRNAs. Consensus Clustering Analysis was performed for samples subtyping based on survival-related lncRNAs, followed by analyzing tumor infiltrating immune cells (TIICs). Optimal signature lncRNAs were obtained using lasso Cox regression analysis for constructing a prognostic model and a nomogram to predict prognosis. RESULTS: We built a co-expression network of 23 m6A-related genes, 15 m5C-related genes, and 62 lncRNAs. Based on 9 m6A- and m5C-related lncRNAs significantly associated with overall survival (OS) time, two molecular subtypes were obtained, which had significantly different OS time and fractions of TIICs. A prognostic model based on six m6A- and m5C-related signature lncRNAs was constructed, which could dichotomize patients into two risk subgroups with significantly different OS time. Prognostic power of the model was successfully validated in an independent dataset. We subsequently constructed a nomogram which could accurately predict survival probabilities. Drug sensitivity analysis found preferred chemotherapeutic agents for high and low-risk patients, respectively. CONCLUSION: Our study reveals that m6A- and m5C-related lncRNAs are associated with prognosis and immune microenvironment of CC. The m6A- and m5C-related six-lncRNA signature may be a useful tool for survival stratification in CC and open new avenues for individualized therapies.

AI-based IsAb2.0 for antibody design.

Therapeutic antibody design has garnered widespread attention, highlighting its interdisciplinary importance. Advancements in technology emphasize the critical role of designing nanobodies and humanized antibodies in antibody engineering. However, current experimental methods are costly and time-consuming. Computational approaches, while progressing, faced limitations due to insufficient structural data and the absence of a standardized protocol. To tackle these challenges, our lab previously developed IsAb1.0, an in silico antibody design protocol. Yet, IsAb1.0 lacked accuracy, had a complex procedure, and required extensive antibody bioinformation. Moreover, it overlooked nanobody and humanized antibody design, hindering therapeutic antibody development. Building upon IsAb1.0, we enhanced our design protocol with artificial intelligence methods to create IsAb2.0. IsAb2.0 utilized AlphaFold-Multimer (2.3/3.0) for accurate modeling and complex construction without templates and employed the precise FlexddG method for in silico antibody optimization. Validated through optimization of a humanized nanobody J3 (HuJ3) targeting HIV-1 gp120, IsAb2.0 predicted five mutations that can improve HuJ3-gp120 binding affinity. These predictions were confirmed by commercial software and validated through binding and neutralization assays. IsAb2.0 streamlined antibody design, offering insights into future techniques to accelerate immunotherapy development.

Reversible cold-induced lens opacity in a hibernator reveals a molecular target for treating cataracts.

Maintaining protein homeostasis (proteostasis) requires precise control of protein folding and degradation. Failure to properly respond to stresses disrupts proteostasis, which is a hallmark of many diseases, including cataracts. Hibernators are natural cold-stress adaptors; however, little is known about how they keep a balanced proteome under conditions of drastic temperature shift. Intriguingly, we identified a reversible lens opacity phenotype in ground squirrels (GSs) associated with their hibernation-rewarming process. To understand this "cataract-reversing" phenomenon, we first established induced lens epithelial cells differentiated from GS-derived induced pluripotent stem cells, which helped us explore the molecular mechanism preventing the accumulation of protein aggregates in GS lenses. We discovered that the ubiquitin-proteasome system (UPS) played a vital role in minimizing the aggregation of the lens protein αA-crystallin (CRYAA) during rewarming. Such function was, for the first time to our knowledge, associated with an E3 ubiquitin ligase, RNF114, which appears to be one of the key mechanisms mediating the turnover and homeostasis of lens proteins. Leveraging this knowledge gained from hibernators, we engineered a deliverable RNF114 complex and successfully reduced lens opacity in rats with cold-induced cataracts and zebrafish with oxidative stress-related cataracts. These data provide new insights into the critical role of the UPS in maintaining proteostasis in cold and possibly other forms of stresses. The newly identified E3 ubiquitin ligase RNF114, related to CRYAA, offers a promising avenue for treating cataracts with protein aggregates.

Perioperative outcomes of robot-assisted versus laparoscopic distal gastrectomy for gastric cancer: a systematic review and meta-analysis of propensity score matching studies.

The aim of this meta-analysis was to compare the efficacy of robot distal gastrectomy (RDG) versus laparoscopic distal gastrectomy (LDG) for gastric cancer. Studies included only those that utilized propensity score matching (PSM). A systematic literature search was conducted in several major global databases, including PubMed, Embase, and Google Scholar, up to June 2024. Articles were screened based on predefined inclusion and exclusion criteria. Baseline data and primary and secondary outcome measures (e.g., operative time, estimated blood loss, lymph-node yield dissection, length of hospital stay, and time to first flatus) were extracted. The quality of PSM studies was assessed using the ROBINS-I, and data were analyzed using Review Manager 5.4.1 software. A total of 12 propensity score-matched studies involving 3688 patients were included in this meta-analysis. Robot-assisted surgery resulted in a longer operative time (WMD 30.64 min, 95% CI 15.63 - 45.66; p < 0.0001), less estimated blood loss (WMD 29.54 mL, 95% CI - 47.14 - 11.94; p = 0.001), more lymph-node yield (WMD 5.14, 95% CI 2.39 - 7.88; p = 0.0002), and a shorter hospital stay (WMD - 0.36, 95% CI - 0.60 - 0.12; p = 0.004) compared with laparoscopic surgery. There were no significant differences between the two surgical methods in terms of time to first flatus, overall complications, and major complications. Robot distal gastrectomy for gastric cancer reduces intraoperative blood loss, increases lymph-node yield, and shortens hospital stay compared with laparoscopic surgery, despite a longer operative time. There are no significant differences in time to first flatus and complication rates between the two groups.

Preparation and characterization of kelp polysaccharide and its research on anti-influenza a virus activity.

The beneficial effects of kelp polysaccharide (KPS) have recently attracted attention. In this study, KPS was extracted from kelp using the enzyme hydrolysis combined with freeze-drying, namely, KPS-EF. The structural characterization showed that KPS-EF was a highly sulfated macromolecule with the Mw of 764.2 kDa and the sulfate content of 23.49 %. The antiviral activity of KPS-EF in vitro was verified, and the IC50 value of KPS against the PR8 virus was 0.58 mg/mL. Intranasal administration of KPS-EF significantly inhibited death and weight loss in IAV-infected mice and alleviated virus-induced pneumonia symptoms, meanwhile, KPS-EF (10 mg/kg/day) significantly decreased the production levels of chemokines (CXCL1, RANTES) and inflammatory cytokines (IL-6, TNF-α) in lungs (p < 0.05). KPS-EF could downregulate the activity of viral neuraminidase (NA) primarily in the late stage of viral adsorption with an IC50 value of 0.29 mg/mL. This study provides a theoretical basis for the using KPS as a supplement to NA inhibitors or anti-influenza drugs.

Preparation of sulfated arabinogalactan-loaded hydrogel for wound healing in mouse burn model.

Sulfation of polysaccharides can affect their biological activity by introducing sulfate groups. Skin burns occur regularly and have a great impact on normal survival. In this study, sulfated arabinogalactan (SAG) was prepared by sulfation, and polyvinyl alcohol (PVA) was used to prepare hydrogels for the treatment of scalded skin in mouse. The results show that the main chain of SAG consists of →3-ß-D-Galactose (Gal)-(1, →3, 6)-ß-D-Gal-(1 and →4)-ß-d-Glucose (Glc)-(1. The chain is a neutral polysaccharide composed of T-ß-L-Arabinose (Araf)-(1→, with a molecular weight of 17.9 kDa. At the same time, PVA + SAG hydrogel can promote the scald repair of mouse skin by promoting collagen deposition and angiogenesis, and regulating the TLR4/MyD88/NF-κB signaling pathway. Interestingly, the effect of SAG on promoting the repair of scald wounds is enhanced after AG is derivatized by sulfation. Therefore, the preparation of SAG by sulfation can promote scald repair, and has great application potential in the field of food and medicine.

Huperzine A targets Apolipoprotein E: A potential therapeutic drug for diabetic nephropathy based on omics analysis.

AIMS: Diabetic nephropathy (DN) is a major complication of diabetes mellitus (DM) without curative interventions currently. Huperzine A (Hup A), a natural alkaloid, has demonstrated significant hypoglycemic and anti-inflammatory effects. We aim to investigate the protective effects of Hup A on DN and explore the underlying mechanisms METHODS: We applied STZ induced diabetic rats as DN model and leveraged combination analysis of the transcriptome, metabolome, microbiome, and network pharmacology (NP). The total effect of Hup A on DN was detected (i.e. urine protein, renal tissue structure) and the differential genes were further verified at the level of diabetic patients, db/db mice and cells. Clinical data and small interfering RNA (siRNA)-Apoe were adopted. RESULTS: Hup A alleviated kidney injury in DN rats. Transcriptomics data and Western blot indicated that the improvement in DN was primarily associated with Apoe and Apoc2. Additionally, metabolomics data demonstrated that DN-induced lipid metabolism disruption was regulated by Hup A, potentially involving sphingosine. Hup A also enriched microbial diversity and ameliorated DN-induced microbiota imbalance. Spearman's correlation analysis demonstrated significant associations among the transcriptome, metabolome, and microbiome. Apoe level was positively correlated with clinical biomarkers in DN patients. Si-Apoe also played protective role in podocytes. NP analysis also suggested that Hup A may treat DN by modulating lipid metabolism, microbial homeostasis, and apoptosis, further validating our findings. CONCLUSIONS: Collectively, we provide the first evidence of the therapeutic effect of Hup A on DN, indicating that Hup A is a potential drug for the prevention and treatment of DN.

Altered functional connectivity of resting-state networks and the correlation with clinical characteristics in intermittent exotropia adult patients: a resting-state magnetic resonance imaging study.

BACKGROUND: The pathogenesis of intermittent exotropia (IXT) remains unclear. The study aims to investigate alterations of resting-state networks (RSNs) in IXT adult patients using resting-state functional magnetic resonance imaging (rs-fMRI) data to explore the potential neural mechanisms. METHODS: Twenty-six IXT adult patients and 22 age-, sex-, handedness-, and education-matched healthy controls (HCs) underwent fMRI scanning and ophthalmological examinations. Brain areas with significant functional connectivity (FC) differences between the IXT and HC groups were selected as regions of interest (ROI) and mean z-scores were calculated to control for individual differences. RESULTS: Compared with HCs, IXT patients exhibited altered FC in various brain regions within RSNs involved in binocular fusion, stereopsis, ocular movement, emotional processes and social cognition, including the default mode network (DMN), the dorsal attention network (DAN), the visual network (VN), the sensorimotor network (SMN), the executive control network (ECN), the frontoparietal network (FPN) and the auditory network (AN). The degree of exodeviation was positively correlated with FC value of left middle occipital gyrus (MOG) within the VN. Correspondingly, we found a negative correlation between the degree of exodeviation and the FC value of left angular gyrus (AG) within FPN (P < 0.05). The FNC analysis between different RSNs also provides evidence on visual-motor cortical plasticity. CONCLUSIONS: IXT patients showed widespread changes of brain activity within RSNs related to binocular fusion, stereopsis, oculomotor control, emotional processes, and social cognition. These findings extend our current understanding of the neuropathological mechanisms of IXT. TRIAL REGISTRATION: Beginning date of the trial: 2021-09-01. Date of registration:2021-07-18. Trial registration number: ChiCTR 2,100,048,852. Trial registration site: http://www.chictr.org.cn/index.aspx .

Achievement of recommended targets for cardiovascular disease prevention in adults with diabetes in 38 low- and middle-income countries.

Background: Implementation of guideline recommendations for cardiovascular disease (CVD) prevention in people with diabetes in low- and middle-income countries (LMICs) is unclear. We assessed the achievement of CVD prevention targets among patients with diabetes in LMICs. Methods: We pooled nationally representative cross-sectional surveys from 38 LMICs. We evaluated three targets according to the World Health Organization's (WHO) recommendations: treatment (glucose-lowering drugs, statins, antihypertensive drugs, and aspirin); metabolism (blood glucose, body mass index, blood pressure, and cholesterol); and lifestyle (non-smoking, non-drinking, physical activity, and diet). We used multivariable Poisson regression models to assess sociodemographic factors influencing adherence to guideline recommendations. Results: The study included 110 083 participants, of whom 6789 (6.0%) had self-reported diabetes. The prevalence of achieving the treatment, metabolic and lifestyle targets for all components were 9.9%, 8.1%, and 7.2%, respectively. The components with the lowest prevalence of the three targets were 11.1% for statin use, 27.3% for body mass index control, and 19.5% for sufficient consumption of fruit and vegetables, respectively. Upper-middle-income countries were better at achieving the treatment, non-drinking, and dietary targets than lower-middle-income countries. Women, middle-aged and older patients, and highly educated patients had a lower prevalence of metabolic adherence. Conclusions: In LMICs, the prevalence of patients with diabetes meeting WHO-recommended treatment, metabolic and lifestyle targets for CVD prevention was low. Our findings highlighted the need to strengthen the prevention of CVD in patients with diabetes in LMICs.

Investigating the influence of varied ratios of red and far-red light on lettuce (Lactuca sativa): effects on growth, photosynthetic characteristics and chlorophyll fluorescence.

Far red photon flux accelerates photosynthetic electron transfer rates through photosynthetic pigments, influencing various biological processes. In this study, we investigated the impact of differing red and far-red light ratios on plant growth using LED lamps with different wavelengths and Ca1.8Mg1.2Al2Ge3O12:0.03Cr3+ phosphor materials. The control group (CK) consisted of a plant growth special lamp with 450 nm blue light + 650 nm red light. Four treatments were established: F1 (650 nm red light), F2 (CK + 730 nm far-red light in a 3:2 ratio), F3 (650 nm red light + 730 nm far-red light in a 3:2 ratio), and F4 (CK + phosphor-converted far-red LED in a 3:2 ratio). The study assessed changes in red and far-red light ratios and their impact on the growth morphology, photosynthetic characteristics, fluorescence characteristics, stomatal status, and nutritional quality of cream lettuce. The results revealed that the F3 light treatment exhibited superior growth characteristics and quality compared to the CK treatment. Notably, leaf area, aboveground fresh weight, vitamin C content, and total soluble sugar significantly increased. Additionally, the addition of far-red light resulted in an increase in stomatal density and size, and the F3 treatments were accompanied by increases in net photosynthetic rate (Pn), transpiration rate (Tr), intercellular CO2 concentration (Ci), and stomatal conductance (Gs). The results demonstrated that the F3 treatment, with its optimal red-to-far-red light ratio, promoted plant growth and photosynthetic characteristics. This indicates its suitability for supplementing artificial light sources in plant factories and greenhouses.

[Spatiotemporal Variation Characteristics of Ozone and Identification of Key Influencing Factors Based on Random Forest Model： A Case Study of Chuzhou City].

The cause of ozone pollution is a complex scientific problem. Studying the spatiotemporal variation characteristics of O3 at different time scales and analyzing the key influencing factors of O3 concentration is of great significance for the precise formulation of urban air pollution control measures and the improvement of urban air quality. Based on the analysis of the spatiotemporal variation characteristics of O3 concentration in Chuzhou City, we studied the 12 ozone-influencing factors of meteorology and pollutants at multiple time scales using Spearman correlation analysis and a random forest model. The results showed that： ① The O3 pollution level of Chuzhou City showed an aggravating trend, and the O3 concentration distribution showed a spatial pattern of "high in the southeast and low in the northwest." ② From February to May, SO2 concentration had a strong impact on the increase in O3 concentration. From June to September, PM2.5 and PM10 were significantly positively correlated with ozone and had a greater impact. ③ Relative humidity, temperature, and wind speed had a significant impact on O3, whereas barometric pressure and hourly rainfall had a weak impact. ④ The O3 pollution mechanism in Chuzhou City changed from "pollutant-controlled" to "meteorology-controlled." ⑤ Among meteorological and pollutant factors, the three influencing factors that had the greatest influence on O3 concentration were temperature, wind speed, and relative humidity, with PM10 concentration, PM2.5 concentration, and SO2 concentration also contributing. All of the above six influencing factors had a significant nonlinear relationship with the O3 concentration.

[Pollution Evaluation and Risk Control Suggestion of Heavy Metals in Soil-crop System in Different Soil Parent Material Areas of Guangxi].

To study the heavy metal pollution and influencing factors of soils and crops in different parent material areas and provide the basis for the classification and control of cultivated land, a total of 1 326 soil surface samples and 46 crop seed-root soil samples were collected from Xingye County in the southeast of Guangxi. The enrichment characteristics of heavy metals in the soil-crop system of four soil-forming parent materials were compared and analyzed, and the influencing factors of Cd absorption by rice were studied. The comprehensive quality impact index method was used to evaluate the soil and crops in the study area, and the safe use of cultivated land was proposed according to the evaluation results. The results showed that in the four soil-forming parent material areas, only the carbonate rock parent material area showed obvious enrichment of heavy metals in the soil, especially Cd. According to the "National Food Safety Standard for the Limit of Pollutants in Food" （GB 2762-2022）, the excess rate of heavy metal Cd in rice seeds was 35.7%, and the other heavy metal rates were not exceeded. The bioconcentration coefficient of heavy metal Cd in rice from different parent material areas was as follows： quaternary sediment area > carbonate parent material area > clastic parent material area > granite parent material area. The enrichment of Cd in rice was affected by soil pH and CaO. When the soil pH value was in the range of 5.5-6.5, the Cd content and exceeding rate of rice seed increased significantly. The evaluation results of soil-crop heavy metal pollution showed that the overall heavy metal risk in the study area was high, and the proportions of clean, mild, light, moderate, and heavy pollution were 23.91%, 10.87%, 17.39%, 17.39%, and 30.43%, respectively. Combined with the distribution of the comprehensive quality influence index and the pollution characteristics of different parent materials, the classification and control suggestions were put forward, which provided ideas for the safe utilization of polluted cultivated land.

[Pollution Characteristics and Source Apportionment of Heavy Metals in Topsoil of Counties Along the Shandong Section of the Yellow River].

The 25 counties along the Shandong section of the Yellow River are the core areas for promoting the ecological protection and high-quality development of the Yellow River in Shandong Province. Moreover, it is of great significance to study the current situation, sources, and potential risks of heavy metal pollution in the topsoil in this region. In this study, 103 soil samples were collected from the 25 counties along the Shandong section of the Yellow River, and the contents of eight heavy metals （As, Cu, Pb, Cr, Zn, Ni, Cd, and Hg） were determined. The pollution characteristics of heavy metals were analyzed and evaluated using the geological accumulation index and potential ecological risk index. Correlation analysis and the positive matrix factorization （PMF） model were used to analyze the sources of heavy metals. The results showed that the average contents of Cu and Cr were lower than that of the background values of soils, whereas the average contents of As, Pb, Zn, Ni, Cd, and Hg were 1.16, 1.42, 1.05, 1.14, 2.29, and 1.85 times higher than that of the background values, respectively, and the average contents of all eight elements were lower than the screening value of soil pollution risk in agricultural land. In terms of different heavy metal variations, the coefficient of variation （CV） of Cu and Cd was higher than 0.500, indicating high variations, whereas As, Pb, Cr, Zn, Ni, and Hg showed moderate variation. Cd and Hg were slightly polluted, whereas the other six elements were not polluted. Cd and Hg had a moderate potential ecological risk level, whereas the other six elements were at a low level. Correlation analysis and PMF model showed that the sources of heavy metals in the study area were influenced by four factors, i.e., agricultural activities, natural sources, industrial emissions, and atmospheric dust from coal combustion and vehicle exhaust emissions, and the relative contribution rates were 32.4%, 34.9%, 16.5%, and 16.2%, respectively.