Publications by authors named "Jianwei Peng"

8 Publications

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The effects of the depth of fertilization on losses of nitrogen and phosphorus and soil fertility in the red paddy soil of China.

PeerJ 2021 18;9:e11347. Epub 2021 May 18.

College of Resources and Environmental, Hunan Agricultural University, Changsha, China.

Nitrogen (N) and phosphorus (P) losses from agroecosystems are dominant nonpoint pollution. To minimize the losses of N and P, the optimal depth of fertilization was explored using a soil column study with the red paddy soil as the research objects. The losses of N and P were measured under five depths of fertilization (0, 5, 7.5, 10, and 12.5 cm) as well as no fertilization. The results showed that ammonia volatilization was significantly decreased with increasing fertilization depth within 010 cm, and there was no significant difference among the 10 cm, 12.5 cm, and no-fertilization treatments. Comparing with surface fertilization (0 cm), N and P losses by runoff could be reduced by 30.767.1% and 96.998.7% respectively by fertilization at 512.5 cm. In addition, deep fertilization (512.5 cm) did not increase N and P losses by leaching at the depth of 40 cm. Total N and P contents in the tillage layer of soil were increased by 5.1 to 22.8% and by 1.0 to 7.5%, respectively. Fertilization at 10cm depth has the potential to minimal environmental impact in the red paddy soil of south China, at this depth, NH volatilization was reduced by 95.1%, and N and P losses by runoff were reduced by 62.0% and 98.4%, respectively, compared with surface fertilization.
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http://dx.doi.org/10.7717/peerj.11347DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8139273PMC
May 2021

Nitrogen removal characteristics of a novel heterotrophic nitrification and aerobic denitrification bacteria, Alcaligenes faecalis strain WT14.

J Environ Manage 2021 Mar 16;282:111961. Epub 2021 Jan 16.

Key Laboratory of Agro-ecological Processes in Subtropical Regions, Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.

Alcaligenes faecalis strain WT14 is heterotrophic nitrification and aerobic denitrification bacterium, newly isolated from a constructed wetland, and its feasibility in nitrogen removal was investigated. The result showed sodium citrate was more readily utilized by WT14 as a carbon source. The response surface methodology model revealed the highest total nitrogen removal by WT14 occurred at 20.3 °C, 113.5 r·min, C/N 10.8, and pH 8.4. Under adapted environmental conditions, up to 55.9 mg·L·h of ammonium nitrogen (NH-N) was removed by WT14, and its NH-N tolerance ability reached 2000 mg·L. In addition to the reported high NH-resistance of Alcaligenes faecalis, WT14 multiplied fast and had strong nitrate or nitrite removal capacity when high strength nitrate or nitrite was provided as the single nitrogen source; which differed from other Alcaligenes faecalis species. These results show WT14 is a novel strain of Alcaligenes faecalis and its nitrogen removal pathway will be carried out in the further study.
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http://dx.doi.org/10.1016/j.jenvman.2021.111961DOI Listing
March 2021

High risk of colorectal polyps in men with non-alcoholic fatty liver disease: A systematic review and meta-analysis.

J Gastroenterol Hepatol 2020 Dec 7;35(12):2051-2065. Epub 2020 Jul 7.

Department of Gastroenterology, The First Affiliated Hospital of Shantou University Medical College, Shantou, China.

Background And Aim: This meta-analysis aims to explore the risk of colorectal polyps among non-alcoholic fatty liver disease (NAFLD) patients.

Methods: We searched PubMed, EMBASE, and Cochrane library databases using predefined search term to identify eligible studies (published up to 7 November 2019). Data from selected studies were extracted by using a standardized information collection form, and meta-analyses were performed using random-effects model. The statistical heterogeneity among studies (I ), subgroup analyses, meta-regression analyses, and the possibility of publication bias were assessed.

Results: Twenty observational (12 cross-sectional, two case-control, and six cohort) studies met the eligibility criteria, involving 142 387 asymptomatic adults. In cross-sectional/case-control studies, NAFLD was found to be associated with an increased risk of colorectal polyps (odds ratio [OR] = 1.34; 95% confidence interval [CI] = 1.23-1.47) (including unclassified colorectal polyps, hyperplastic polyps, adenomas, and cancers) with statistically significant heterogeneity (I  = 67.8%; P < 0.001). NAFLD was also associated with a higher risk of incident colorectal polyps (hazard ratio = 1.60; 95% CI = 1.36-1.87) with low heterogeneity (I  = 21.8%; P = 0.263) in longitudinal studies. The severity of NAFLD was associated with a higher risk of colorectal adenomas (OR = 1.57; 95% CI = 1.30-1.88), but not colorectal cancer (OR = 1.37; 95% CI = 0.92-2.03). The subgroup analysis according to gender showed that NAFLD was significantly associated with a higher risk of colorectal polyps in the male population without significant heterogeneity (OR = 1.47; 95% CI = 1.29-1.67, I  = 0%), but not in the female population (OR = 0.88; 95% CI = 0.60-1.29, I  = 34.2%).

Conclusions: NAFLD was associated with an increased risk of colorectal polyps. There was a significant difference of the relationship between genders, which suggested more precise screening colonoscopy recommendation in NAFLD patients according to gender.
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http://dx.doi.org/10.1111/jgh.15158DOI Listing
December 2020

Metformin's Effects on Apoptosis of Esophageal Carcinoma Cells and Normal Esophageal Epithelial Cells: An In Vitro Comparative Study.

Biomed Res Int 2020 18;2020:1068671. Epub 2020 Mar 18.

Department of Gastroenterology, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, China.

The effect of metformin on human esophageal normal and carcinoma cells remains poorly understood. We aim to investigate the different antiproliferation effects and underlying distinct molecular mechanisms between these two types of cells. Human esophageal squamous cell carcinoma cell line, EC109, and normal esophageal epithelial cell line, HEEC, were used in the experiment. The cell survival rate was determined by cell counting kit-8 (CCK-8). Cell apoptosis was analyzed by flow cytometry. The mRNA and protein levels of signal transducer and activator of transcription 3 (Stat3) were detected by real-time quantitative PCR and western blot. Interleukin-6 (IL-6) was added to activate Stat3. The level of intracellular reactive oxygen species (ROS) was assessed by a DCFH-DA fluorescent probe. Metformin had more significant inhibitory effects on cell proliferation in EC109 cells than HEECs. Metformin induced apoptosis of EC109 cells in a dose-dependent manner instead of HEECs. The expression of Stat3 in both mRNA and protein levels was higher in EC109 cells than HEECs. Further study revealed that metformin may attenuate the phosphorylation of the Stat3 and the Bcl-2 expression, which was restored by IL-6 partly in EC109 cells but not HEECs. On the contrary, metformin increased the level of ROS in both the cell lines, but this intracellular ROS variation had no effect on apoptosis. Metformin has different functional roles on the apoptosis in esophageal carcinoma cells and normal esophageal cells. Therefore, the Stat3/Bcl-2 pathway-mediated apoptosis underlies the cell-type-specific drug sensitivity, suggesting metformin possesses a therapeutic activity and selectivity on esophageal cancer.
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http://dx.doi.org/10.1155/2020/1068671DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7104266PMC
January 2021

Stimulation of optimized influent C:N ratios on nitrogen removal in surface flow constructed wetlands: Performance and microbial mechanisms.

Sci Total Environ 2019 Dec 23;694:133575. Epub 2019 Jul 23.

Key Laboratory of Agro-ecological Processes in Subtropical Regions, Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan 410125, PR China.

Exploring optimal C:N ratio is necessary to ensure balanced microbial nitrification and denitrification in constructed wetlands (CWs), which has become an important management practice for more efficient nitrogen removal and sustainability of CWs. Surface flow constructed wetlands (SFCWs) vegetated with Myriophyllum aquaticum were designed to investigate the effects of five different influent C:N ratios (0:1, 2.5:1, 5:1, 10:1, and 15:1) on nitrogen removal performance and microbial communities over a 175-day experimental period. Compared to the influent C:N ratios of 0:1, higher NH-N, NO-N, and total nitrogen (TN) removal efficiencies and lower NO-N accumulation were observed at influent C:N ratios higher than 5:1. In addition, the highest TN removal efficiency (70.4%) and the lowest nitrous oxide emission flux (4.12 mg m d) were obtained at the influent C:N ratio of 5:1. High-throughput sequencing revealed that influent C:N ratios altered the distribution and composition of microbial communities in the sediment, which resulted in a dynamic interplay between N-transforming functional microbes and NH-N and NO-N removal. In particular, the dominant denitrifiers, including Desulfovibrio, Zoogloea, and Dechloromonas, were more abundant in the sediment with an influent C:N ratio of 5:1, which contributed to the high N removal rate. These findings may be used to screen for an optimum influent C:N ratio to maintain the sustainability of SFCWs with higher N removal efficiency.
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http://dx.doi.org/10.1016/j.scitotenv.2019.07.381DOI Listing
December 2019

Reduction in nitrogen fertilizer applications by the use of polymer-coated urea: effect on maize yields and environmental impacts of nitrogen losses.

J Sci Food Agric 2019 Mar 8;99(5):2259-2266. Epub 2019 Jan 8.

College of Resources and Environment, Hunan Agricultural University, Changsha, China.

Background: Urea is commonly over-applied as a nitrogen (N) fertilizer to crops in southern China and has a low utilization efficiency as a result of the high precipitation and high temperatures in this region. This has led to a need to optimize the management of N fertilizer use in maize crops on the subtropical hilly uplands of southern China.

Results: We investigated the effects of applying different amounts of N in the form of polymer-coated urea (PCU) on the yield of maize and gaseous losses of N from soils in the form of NH and N O. The field plots used in this trial had zero-added N (0 kg N ha ), the addition of urea (240 kg N ha ) and four levels of fertilization with PCU (1 PCU, 0.9 PCU, 0.8 PCU and 0.7 PCU), which represented a 0%, 10%, 20% and 30% reduction, respectively, in the application of PCU-N relative to the urea plot. Compared to the urea plot, there was little variation in the yield of maize for all the PCU-N treatments, with a significant improvement in the utilization efficiency of N (up to 46.0-51.2%) with a 0-30% reduction in the application of PCU-N. Significant effects in the mitigation of the N O emission flux and the accumulation of N O-N were observed in the 0.8 PCU and 0.7 PCU plots. The application of PCU-N significantly reduced the flux and total amount of NH -N lost to the environment: as the application rate for N decreased by 0-30%, the NH loss was significantly reduced by 12.7-36.1%.

Conclusion: The findings of the present study suggest that the use of PCU could allow a reduction in the application of N of 20-30% compared to traditional agricultural practices in this area with the same yield of maize, although with significantly decreased NH and N O losses and the increased utilization of N. © 2018 Society of Chemical Industry.
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http://dx.doi.org/10.1002/jsfa.9421DOI Listing
March 2019

Trend-Residual Dual Modeling for Detection of Outliers in Low-Cost GPS Trajectories.

Sensors (Basel) 2016 Dec 1;16(12). Epub 2016 Dec 1.

Collaborative Innovation Center of Geospatial Technology, Wuhan University, Wuhan 430079, China.

Low-cost GPS (receiver) has become a ubiquitous and integral part of our daily life. Despite noticeable advantages such as being cheap, small, light, and easy to use, its limited positioning accuracy devalues and hampers its wide applications for reliable mapping and analysis. Two conventional techniques to remove outliers in a GPS trajectory are thresholding and Kalman-based methods, which are difficult in selecting appropriate thresholds and modeling the trajectories. Moreover, they are insensitive to medium and small outliers, especially for low-sample-rate trajectories. This paper proposes a model-based GPS trajectory cleaner. Rather than examining speed and acceleration or assuming a pre-determined trajectory model, we first use cubic smooth spline to adaptively model the trend of the trajectory. The residuals, i.e., the differences between the trend and GPS measurements, are then further modeled by time series method. Outliers are detected by scoring the residuals at every GPS trajectory point. Comparing to the conventional procedures, the trend-residual dual modeling approach has the following features: (a) it is able to model trajectories and detect outliers adaptively; (b) only one critical value for outlier scores needs to be set; (c) it is able to robustly detect unapparent outliers; and (d) it is effective in cleaning outliers for GPS trajectories with low sample rates. Tests are carried out on three real-world GPS trajectories datasets. The evaluation demonstrates an average of 9.27 times better performance in outlier detection for GPS trajectories than thresholding and Kalman-based techniques.
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http://dx.doi.org/10.3390/s16122036DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5191017PMC
December 2016

Exploiting Co-Benefits of Increased Rice Production and Reduced Greenhouse Gas Emission through Optimized Crop and Soil Management.

PLoS One 2015 9;10(10):e0140023. Epub 2015 Oct 9.

Rothamsted Research, Harpenden, Herts, United Kingdom.

Meeting the future food security challenge without further sacrificing environmental integrity requires transformative changes in managing the key biophysical determinants of increasing agronomic productivity and reducing the environmental footprint. Here, we focus on Chinese rice production and quantitatively address this concern by conducting 403 on-farm trials across diverse rice farming systems. Inherent soil productivity, management practices and rice farming type resulted in confounded and interactive effects on yield, yield gaps and greenhouse gas (GHG) emissions (N2O, CH4 and CO2-equivalent) with both trade-offs and compensating effects. Advances in nitrogen, water and crop management (Best Management Practices-BMPs) helped closing existing yield gaps and resulted in a substantial reduction in CO2-equivalent emission of rice farming despite a tradeoff of increase N2O emission. However, inherent soil properties limited rice yields to a larger extent than previously known. Cultivating inherently better soil also led to lower GHG intensity (GHG emissions per unit yield). Neither adopting BMPs only nor improving soils with low or moderate productivity alone can adequately address the challenge of substantially increasing rice production while reducing the environmental footprint. A combination of both represents the most efficient strategy to harness the combined-benefits of enhanced production and mitigating climate change. Extrapolating from our farm data, this strategy could increase rice production in China by 18%, which would meet the demand for direct human consumption of rice by 2030. It would also reduce fertilizer nitrogen consumption by 22% and decrease CO2-equivalent emissions during the rice growing period by 7% compared with current farming practice continues. Benefits vary by rice-based cropping systems. Single rice systems have the largest food provision benefits due to its wider yield gap and total cultivated area, whereas double-rice system (especially late rice) contributes primarily to reducing GHG emissions. The study therefore provides farm-based evidence for feasible, practical approaches towards achieving realistic food security and environmental quality targets at a national scale.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0140023PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4599856PMC
July 2016
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