[Traceability Analysis and Environmental Quality Assessment of Soil Heavy Metal Pollution in West Hunan Province].

In order to explore the status of soil heavy metal pollution and environmental quality in west Hunan, relevant areas of Phoenix County were selected as the study area. Using data from 440 soil samples collected in the study area from June to August 2022, the pH value of the soil and contents of eight heavy metal elements, namely, As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, were analyzed. The PMF model was used for traceability analysis and geochemical evaluation of soil environmental quality. The results showed that the average values of soil heavy metals ω(Zn), ω(Cr), ω(Pb), ω(Ni), ω(Cu), ω(As), ω(Cd), and ω(Hg) were 81.02, 64.67, 31.63, 29.27, 25.52, 9.93, 0.28, and 0.13 mg·kg-1, respectively. The soil in the study area was mainly weakly acidic, and the contents of the Cd and Hg elements were relatively high compared to the national soil background values and were highly variable. The contents of the Hg and Cd elements in forest land were higher than that in other land uses. The PMF model results showed that the contribution rates of heavy metal pollution sources in the study area were mining sources (37.4%), atmospheric sedimentation sources (7.7%), natural sources (41.1%), and agricultural activity sources (13.8%) and provided suggestions on pollution control measures according to the spatial distribution of the four types of pollution sources. Through the comprehensive assessment of soil environmental geochemistry, the study area was divided into three types of plots, namely, non-risk areas (94.27 km2), accounting for 76.38%; risk-controllable areas (27.45 km2), accounting for 22.24%; and high-risk areas (1.7 km2), accounting for 1.38%. This study provided data support for the prevention and control measures of land pollution in the research area, as well as the delineation of the prevention and control scope.

The effects of photoperiod and temperature-related factors on maize leaf number and leaf positional distribution in the field.

Quantifying the effects of various environmental conditions on maize leaf number is essential to understanding the environmental adaptations and population structure of maize plants and for enhancing maize productivity. In this study, seeds of three temperate-adapted maize cultivars, each belonging to different maturity classes, were sown on eight different dates. Sowing dates ranged from the middle of April to early July, which allowed us to cover a wide range of environmental conditions. Random forest regression and multiple regression models with variance partitioning analyses were used to assess the effects of environmental factors on the number of leaves and their distributions on maize primary stems. We demonstrated that the total leaf number (TLN) increased in the three cultivars in the following order: FK139 < JNK728 < ZD958, and variations in TLN for each cultivar were 1.5, 1.76, and 2.75 leaves, respectively. The variation in TLN was ascribed to changes in LB (leaf number below the primary ear), which were higher than variations in LA (leaf number above the primary ear). Variations in TLN and LB were mainly affected by the photoperiod during growth stages V7 to V11, and differences in TLN and LB in response to different photoperiods ranged from 1.34 to 2.95 leaves h-l. Variations in LA was mainly affected by temperature-related factors. Therefore, the results of this study enhanced our current understanding of key environmental conditions that affect maize leaf numbers, and provides scientific support for the benefits of adjusting sowing dates and selecting suitable cultivars to mitigate the effects of climate change on maize production.

Quantitative analysis of maize leaf collar appearance rates.

Phyllochron, the reciprocal of the leaf appearance rate, is a critical genetic parameter in crop models for predicting growth characteristics and yield. Previous studies have shown that existing observations and predictive algorithms do not adequately represent a broad range of cultivars and environments. Here, we conducted a series of experiments in the field to quantify and disentangle the effects of sowing date and cultivar on maize leaf collar appearance (LCA). A bilinear model was found to accurately fit maize LCA (R2adj > 0.99); this model revealed a slower rate of LCA for the first leaves compared to the last leaves. Turning points in the model occurred between the 9.2th and the 13.1th leaf, nearly always below the ear leaf and around a leaf age index (LAI) of 60.0%. The phyllochron before the turning point (PHYLL Ⅰ) was significantly higher than the phyllochron after the turning point (PHYLL Ⅱ) for all three maize cultivars, and PHYLL Ⅰ was approximately two times higher than PHYLL Ⅱ on average. Both PHYLL Ⅰ and PHYLL Ⅱ were significantly affected by sowing date and cultivar. Variations in PHYLL Ⅰ and PHYLL Ⅱ indicated strong plasticity in maize phyllochron at different leaf ranks. The results of this study are critical for improvement of maize management practices and extend the applicability of phyllochron-collar measurements in crop models.

[Geochemical Characteristics of Cd in Different Parent Soils in Karst Area and Prediction of Cd Content in Maize].

The naturally high background value region of Cd derived from the weathering of carbonate has received wide attention. Due to the significant difference in soil physicochemical properties, soil Cd content, and bioavailability of different parent materials in the karst area, there are certain limitations in using the total soil Cd content to classify the environmental quality of cultivated land. In this study, surface soil and maize samples of eluvium and alluvial parent material in typical karst areas were collected systematically; the contents of maize Cd, soil Cd, pH, and oxides were analyzed, the Cd geochemical characteristics of different parent soils and the influencing factors of their bioavailability were revealed, and scientific and effective arable land use zoning suggestions based on the prediction model were suggested. The results showed that the physicochemical properties of different parent material soils in the karst area were obviously different. The alluvial parent material soil had low Cd content but high bioavailability, and the maize Cd exceeding rate was high. The maize Cd bioaccumulation factor was significantly negatively correlated with soil CaO, pH, Mn, and TC, and the correlation coefficients were -0.385, -0.620, -0.484, and -0.384, respectively. Compared with the multiple linear regression prediction model, using the random forest model to predict the maize Cd enrichment coefficient had higher accuracy and precision. Furthermore, a new scheme for the safe utilization of cultivated land at the plot scale based on soil Cd and predicted crop Cd content was proposed in this study, making full use of arable land resources to ensure crop safety.

Evaluating how lodging affects maize yield estimation based on UAV observations.

Timely and accurate pre-harvest estimates of maize yield are vital for agricultural management. Although many remote sensing approaches have been developed to estimate maize yields, few have been tested under lodging conditions. Thus, the feasibility of existing approaches under lodging conditions and the influence of lodging on maize yield estimates both remain unclear. To address this situation, this study develops a lodging index to quantify the degree of lodging. The index is based on RGB and multispectral images obtained from a low-altitude unmanned aerial vehicle and proves to be an important predictor variable in a random forest regression (RFR) model for accurately estimating maize yield after lodging. The results show that (1) the lodging index accurately describes the degree of lodging of each maize plot, (2) the yield-estimation model that incorporates the lodging index provides slightly more accurate yield estimates than without the lodging index at three important growth stages of maize (tasseling, milking, denting), and (3) the RFR model with lodging index applied at the denting (R5) stage yields the best performance of the three growth stages, with R2 = 0.859, a root mean square error (RMSE) of 1086.412 kg/ha, and a relative RMSE of 13.1%. This study thus provides valuable insight into the precise estimation of crop yield and demonstra\tes that incorporating a lodging stress-related variable into the model leads to accurate and robust estimates of crop grain yield.

Improvement in the condition of patients with primary liver cancer with transcatheter arterial chemoembolization before and after microwave ablation interventional therapy.

BACKGROUND: We compared the clinical efficacy and safety of transcatheter arterial chemoembolization (TACE) combined with microwave ablation (MWA) and TACE alone for the treatment of patients with primary liver cancer (PLC). MATERIALS AND METHODS: A total of 160 patients with PLC were enrolled and randomized into a study group (n=80) and a control group (n=80). Patients in the study group were treated with TACE combined with MWA, whereas those in the control group were treated with TACE alone. Treatment efficacy, changes in hepatic function indices after the treatment, incidence of adverse reactions, quality of life after treatment, and 3-year survival rates of the two groups were compared. Cox proportional hazards model was used for analyzing the patients' prognostic factors. RESULTS: The total effective rate in the study group was higher than that in the control group (P<0.05). Patients in the study group had lower alanine aminotransferase and total bilirubin levels (P<0.05) and higher albumin levels (P<0.05) than those in the control group. The 1-, 2-, and 3-year overall survival rates in the study group were higher than those in the control group (P<0.05). Cox proportional hazards model showed that tumor size, extrahepatic metastasis, portal vein tumor thrombosis, severity of liver cirrhosis, and therapeutic methods were independent risk factors for patients with PLC. CONCLUSIONS: TACE combined with MWA is more effective than TACE alone in treating PLC, reducing the damage to the patients' cardiac function and prolonging survival.

Laparoscopic spleen retains the body and tail of the pancreas resection.

Pancreatic serous cystic neoplasm (SCN) is a benign tumor of the pancreas, about two-thirds situated in the tail of the pancreas. The small sized ones usually require only routine follow-ups, and is advised for surgical treatment when clinical symptoms, and mass growth are occurring rapidly, and the traditional treatment is splenectomy. Here, we have finished a laparoscopy resection of the spleen-preserving pancreatic body. A 46-year-old female presents for a follow-up after a physical examination found a tumor mass in the body and tail of the pancreas two years ago. After the tumor had become fast-growing and appeared to have other clinical symptoms, a final laparoscopy surgery was performed to retain the spleen of the pancreas. After the treatment, and a smooth recovery, the patient had been discharged. Spleen preserving laparoscopy, with distal pancreatectomy, in the treatment of benign tumors of the pancreatic body and tail, not only can reflect a minimally invasive treatment of postoperative pain, it provides a light and quick recovery advantage. The preservation of the spleen to avoid the long-term anticoagulation treatment, and the technology being relatively easily available, did not significantly increase the incidence of postoperative complications. It is worth using the clinic.