22 research outputs found
Detection and enrichment characteristics analysis of common heavy metal content in different organs of Hunan lotus seed
Objective: The objective of this study is to investigate the heavy metal content in sediment and various organs of Hunan lotus seed in a planting area, as well as to explore the characteristics of heavy metal accumulation and transfer in Hunan lotus seed. Methods: A typical planting area in Hunan Province was selected for this research. The contents of Cd, Cr, Pb, Ni, Cu, Zn and Mn were measured using an inductively coupled plasma emission spectrometer. The bioconcentration factor (BCF) and transfer factor (TF) were used to evaluate the heavy metal accumulation and transfer ability of Hunan lotus seed. Results: The average content of Cd, Cr, Pb, Ni, Cu, Zn, and Mn in the sediment were 0.73, 176.28, 40.48, 27.61, 28.07, 95.57 and 311.68 mg/kg, respectively. Compared with the limit values of NY/T 391—2021, the exceeding rates of Cd, Cr, and Pb content are 100%, 75%, and 10%, respectively. The highest concentrations and contents of these 7 heavy metals were Cd, Cu and Zn in the lotus core, Cr and Pb in the root, Ni in the lotus-seed kernel and Mn in the leaves, with an average content of 0.20, 13.64, 78.58, 14.66, 2.23, 1.11 and 924.03 mg/kg, respectively. The BCFMn values for both stems and leaves exceeded 1. The TFCu values for all organs were greater than 1. Conclusion: This study reveals that there is serious pollution from Cd within the study area. The content of heavy metals in different organs of Hunan lotus seed is different. Lotus stems and leaves has strong enrichment of Mn, and Cu had strong transfer ability in Hunan lotus seed
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Effects of florfenicol exposure during early life on toxicity, gut microbiota, and fecal metabolome in SD rats
Florfenicol (FLO) is a third-generation veterinary antibiotic with a high residue detection rate in food, which cause the toxicity of FLO even at low doses, receiving notable attention. The impact of FLO exposure during early life on health and gut microbiota is still unclear. Here, the effects of FLO exposure on toxicity, gut microbiota, drug resistance genes, and the fecal metabolome during early life were investigated in suckling Sprague-Dawley (SD) rats. The results showed that FLO exposure during early life significantly increased the body weight, and WBC and LY levels in the blood, induced inflammation in the liver and intestines. FLO had a dose-dependent effect on the alpha and beta diversity of the gut microbiota, increasing the ratio of Firmicutes to Bacteroides and the abundance of some pathogenic bacteria, and changing the abundance of bacteria related to energy metabolism and inflammation, also promoted the enrichment of drug resistance genes. The fecal metabolome also demonstrated the effect of FLO exposure on metabolic pathways related to energy metabolism and inflammation. In conclusion, this research shows that FLO exposure during early life can lead to excessive weight gain, an inflammatory response, gut microbiota imbalance, the enrichment of drug resistance genes, and effects on related metabolic pathways
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
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A Social Network Analysis of Chinese Tourists’ Image of South Korea in Conflict
This study investigates how bilateral political tensions between China and South Korea influence the image of a destination country, South Korea, and desire of tourists to visit it. In the past decades, Chinese tourists held relatively positive images towards South Korea in aspects of Korean wave, safety, cleanliness, and friendly people, but the deployment of the Terminal High Altitude Area Defense system in South Korea greatly changed perceived images towards South Korea. Given the need to quantify qualitative data of destination image and identify hidden interrelationships of sparse destination images. This study investigates the diversity of image associations that Chinese tourists hold towards South Korea in the context of current conflict and utilizes network analysis to identify the core-periphery structures of the image. Further, the study explores the impact of the network clusters on Chinese tourists’ overall attitude toward South Korea and intention to visit South Korea
Application and Development Countermeasures of CCUS Technology in China’s Petroleum Industry
Greenhouse gas emissions cause many global problems. Under the strong promotion of the government’s two-carbon goals policy, China’s petroleum industry is actively carrying out the application of carbon capture, utilization, and storage (CCUS). The energy consumption and carbon emissions in China are reviewed, and the importance of the petroleum industry in the process of carbon emission reduction is clarified. The applications, advantages, and disadvantages of carbon capture, carbon utilization, and carbon sequestration technologies in China’s petroleum industry are summarized, respectively. The current challenges and risks faced by China’s petroleum industry in the operation of CCUS projects are analyzed, and corresponding suggestions are provided. This article aims to systematically provide references and help for the application of CCUS in China’s petroleum industry
Application and Development Countermeasures of CCUS Technology in China’s Petroleum Industry
Greenhouse gas emissions cause many global problems. Under the strong promotion of the government’s two-carbon goals policy, China’s petroleum industry is actively carrying out the application of carbon capture, utilization, and storage (CCUS). The energy consumption and carbon emissions in China are reviewed, and the importance of the petroleum industry in the process of carbon emission reduction is clarified. The applications, advantages, and disadvantages of carbon capture, carbon utilization, and carbon sequestration technologies in China’s petroleum industry are summarized, respectively. The current challenges and risks faced by China’s petroleum industry in the operation of CCUS projects are analyzed, and corresponding suggestions are provided. This article aims to systematically provide references and help for the application of CCUS in China’s petroleum industry
Determination of Senegenin and Tenuifolin in Mouse Blood by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry and Their Pharmacokinetics
An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of senegenin and tenuifolin in mouse blood was developed. The pharmacokinetics of senegenin and tenuifolin in mice after intravenous (5 mg/kg) and oral (60 mg/kg) administration were studied, and the absolute bioavailability was calculated. A CORTECS T3 column was used, with a column temperature set at 40°C. The mobile phase was acetonitrile and 0.1% formic acid. Gradient elution was adopted, using a flow rate of 0.4 mL/min and an elution time of 4 min. Quantitative analysis was performed using electrospray ionization (ESI) with multiple reaction monitoring (MRM) in negative ion mode. Institute of Cancer Research (ICR) mice were bled from the tail vein after intravenous or oral administration of senegenin and tenuifolin. A UPLC-MS/MS method was established to determine the blood concentrations of each drug in mice, and the noncompartmental model was used to fit the pharmacokinetic parameters. Senegenin and tenuifolin showed a good linear relationship (r > 0.995) within a concentration range of 5–400 ng/mL in mouse blood. The intraday precision was 88%, and the matrix effect was 87–94%. The oral bioavailability of senegenin and tenuifolin in mice was 8.7% and 4.0%, respectively. The established UPLC-MS/MS method is suitable for pharmacokinetic studies of senegenin and tenuifolin in mice
The accuracy of intraocular lens power calculation formulas based on artificial intelligence in highly myopic eyes: a systematic review and network meta-analysis
ObjectiveTo systematically compare and rank the accuracy of AI-based intraocular lens (IOL) power calculation formulas and traditional IOL formulas in highly myopic eyes.MethodsWe screened PubMed, Web of Science, Embase, and Cochrane Library databases for studies published from inception to April 2023. The following outcome data were collected: mean absolute error (MAE), percentage of eyes with a refractive prediction error (PE) within ±0.25, ±0.50, and ±1.00 diopters (D), and median absolute error (MedAE). The network meta-analysis was conducted by R 4.3.0 and STATA 17.0.ResultsTwelve studies involving 2,430 adult myopic eyes (with axial lengths >26.0 mm) that underwent uncomplicated cataract surgery with mono-focal IOL implantation were included. The network meta-analysis of 21 formulas showed that the top three AI-based formulas, as per the surface under the cumulative ranking curve (SUCRA) values, were XGBoost, Hill-RBF, and Kane. The three formulas had the lowest MedAE and were more accurate than traditional vergence formulas, such as SRK/T, Holladay 1, Holladay 2, Haigis, and Hoffer Q regarding MAE, percentage of eyes with PE within ±0.25, ±0.50, and ±1.00 D.ConclusionsThe top AI-based formulas for calculating IOL power in highly myopic eyes were XGBoost, Hill-RBF, and Kane. They were significantly more accurate than traditional vergence formulas and ranked better than formulas with Wang–Koch AL modifications or newer generations of formulas such as Barrett and Olsen.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022335969
Novel Ternary Heterogeneous Reduction Graphene Oxide (RGO)/BiOCl/TiO2 Nanocomposites for Enhanced Adsorption and Visible-Light Induced Photocatalytic Activity toward Organic Contaminants
Herein, we describe a simple and cost-effective design for the fabrication of a novel ternary RGO/BiOCl/TiO2 nanocomposites through a simple hydrothermal process. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (UV–vis DRS) and N2 adsorption–desorption analysis. Organic contaminants—such as methylene blue (MB), methyl orange (MO), rhodamine B (RhB) and amido black-10B (AB-10B)—were employed as the target pollutants to evaluate the adsorption capacity and photocatalytic activity of RGO/BiOCl/TiO2 nanocomposites. From experimental data, it was also found that the amount of TiO2 impressed the photocatalytic performance, and the nanocomposites with 10% of TiO2 showed the best photocatalytic activity. The improved photocatalytic performance may be mainly due to the narrow band gap, and the charge separation and migration of RGO. Moreover, good recyclability was obtained from RGO/BiOCl/TiO2 nanocomposites, and scavenger tests indicated that photogenerated holes were the main active species in the reaction system. Therefore, the prepared RGO/BiOCl/TiO2 nanocomposites have broad applications foreground in pollutants purification
Temporal and Spatial Evolution of Carbon Emissions and Their Influencing Factors for Tourist Attractions at Heritage Tourist Destinations
Carbon emissions play an important role in sustainable tourism development at heritage sites. The study takes the Wulingyuan Scenic and Historic Interest Area (WSHIA) as an example, and primary and secondary data sources are used to measure and estimate the carbon emissions of tourist attractions from 1979 to 2014. The temporal and spatial evolution of carbon emissions and their influencing factors for tourist attractions at heritage tourist destinations are analyzed. The results show that there are great differences in carbon emissions per visitor across the different types of tourism attractions at the heritage tourist destination, and there are significant monthly and interannual differences in the carbon emissions of the tourism attractions in the WSHIA. The main influencing factors include tourism seasonality, the rapid growth of China’s tourism market, and the rising popularity of heritage tourism. The spatial evolution of carbon emissions of the tourist attractions can be divided into three stages, and its main influencing factors include functional zoning and environmental regulation at the heritage sites and diversified evolution of the heritage tourist attractions. The findings of this study could enrich theories of low-carbon tourism and provide the low-carbon development measures of sustainable tourism in heritage tourist destinations for policymakers