513 research outputs found

    Application of Ionic Liquids in the Microwave-Assisted Extraction of Pectin from Lemon Peels

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    Microwave-assisted extraction of pectin from lemon peels by using ionic liquid as alternative solvent was investigated. The extracted pectin was detected by Fourier transform infrared spectra. The extraction conditions were optimized through the different experiments in conjunction with the response surface methodology. A pectin yield of 24.68 % was obtained under the optimal parameters: the extraction temperature of 88°C, the extraction time of 9.6 min, and a liquid-solid ratio of 22.7 ml · g−1. The structure of the pretreated lemon peel samples and the samples after microwave-assisted extraction were characterized by a field emission scanning electron microscope

    Investigation of the shared biological mechanisms and common biomarker APTAF1 of sleep deprivation and mild cognitive impairment using integrated bioinformatics analysis

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    Introduction: The relationship between sleep loss and cognitive impairment has long been widely recognized, but there is still a lack of complete understanding of the underlying mechanisms and potential biomarkers. The purpose of this study is to further explore the shared biological mechanisms and common biomarkers between sleep loss and cognitive impairment.Methods: The mitochondria-related genes and gene expression data were downloaded from the MitoCarta3.0 and Gene Expression Omnibus (GEO) databases. We identified the differentially expressed mitochondrial-related genes by combing the differentially expressed genes (DEGs) in sleep deprivation (SD) and mild cognitive impairment (MCI) datasets with mitochondria-related gene lists. Shared DEGs were then further analyzed for enrichment analysis. Next, the common biomarker was identified using two machine learning techniques and further validated using two independent GEO datasets. Then GSEA and GSVA were conducted to analyze the functional categories and pathways enriched for the common biomarker. Finally, immune infiltration analysis was used to investigate the correlation of immune cell infiltration with the common biomarker in SD and MCI.Results: A total of 32 mitochondrial-related differentially expressed genes were identified in SD and MCI. GO analysis indicated that these genes were significantly enriched for mitochondrial transport, and KEGG analysis showed they were mainly involved in pathways of neurodegenerative diseases. In addition, ATPAF1, which was significantly down-regulated in both SD and MCI, was identified through machine learning algorithms as the common biomarker with favorable diagnostic performance. GSEA and GSVA revealed that ATPAF1 was mainly involved in metabolic pathways, such as oxidative phosphorylation, acetylcholine metabolic process, valine, leucine and isoleucine degradation. Immune infiltration analysis showed that the expression of ATPAF1 was correlated with changes in immune cells, especially those key immune cell types associated with SD and MCI.Discussion: This study firstly revealed that mitochondrial dysfunction may be the common pathogenesis of sleep loss and mild cognitive impairment and identified ATPAF1 as a possible biomarker and therapeutic target involved in SD and MCI

    Effect of Tremella fuciformis Polysaccharides on Fatigue Induced by Oxidative Damage in Exhaustive Exercise Mice

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    Objective: To investigate the effect of Tremella fuciformis polysaccharides (TFP) on oxidative damage induced by exhaustive exercise in mice and analyze its mechanism. Methods: L6 cells were treated with TFP for 48 hours, and the activity of L6 was detected by CCK-8 method. L6 cells were divided into three groups, including the control, H2O2, and H2O2+TFP groups, and incubated for 48 hours. LA levels were measured by a biochemical analyzer, and Nrf2, NQO1, and HO-1 protein levels were detected by Western blot assay. C57BL/6 mice were randomly divided into four groups (n=10 for each group), including model group and model+TFP group (50, 100, 200 mg/kg). The model+TFP groups were continuously gavaged with TFP, while the model group was gavaged with the same dose of distilled water once a day for two consecutive weeks. Exhaustive exercise was performed 30 minutes after the last administration, the duration of exhaustive swimming exercise was recorded, and enzyme-linked immunosorbent assay (ELISA) was used to detect liver glycogen (LG) and skeletal muscle glycogen (MG). ELISA was used to detect blood urea nitrogen (BUN), lactic acid (LA), ROS, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), TNF-α, IL-6 and NF-ÎșBp65 levels. Western blot assay was used to detect the levels of Nrf2, NQO1, and HO-1 proteins. Results: The LA levels of L6 cells in the H2O2 group were significantly (P<0.01) higher than those in the control group, while the protein levels of Nrf2, NQO1, and HO-1 were significantly (P<0.01) lower than those in the control group. TFP could significantly (P<0.01) reduce the LA levels in the culture medium and upregulate the expression of Nrf2, NQO1, HO-1 in L6 cells. TFP could significantly prolong exhaustive swimming time (P<0.01), reduce LA (P<0.01) and BUN (P<0.05, P<0.01) levels, increase liver and muscle glycogen levels (P<0.05, P<0.01), upregulate SOD (P<0.01) and GSH-Px (P<0.01), downregulate MDA (P<0.05, P<0.01) and ROS (P<0.01) levels, and reduce TNF-α (P<0.01), IL-6 (P<0.01) and NF-ÎșBp65 (P<0.01). Compared with the model group, TFP could significantly increase Nrf2 (P<0.05, P<0.01), HO-1 (P<0.05, P<0.01) and NQO-1 (P<0.05, P<0.01) protein expression levels. Conclusion: TFP improved oxidative damage caused by exhaustive swimming by inhibiting oxidative stress and inflammation, and its mechanism was related to regulating the Nrf2/HO-1 signaling pathway

    Local Residents’ Risk Perceptions in Response to Shale Gas Exploitation: Evidence from China

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    In 2014, China became the world’s third country to accomplish shale gas commercial development, following the United States and Canada. China still however lacks a comprehensive analysis of its public’s concerns about potential environmental risks of shale gas exploration, particularly those of local residents near extraction sites. This paper specifically aims to explore risks perceived as associated with shale gas development in the Changning-Weiyuan area of Sichuan Basin, by conducting a face-to-face household survey with 730 participants interviewed. Some 86% of respondents reported their belief that shale gas exploitation causes more than three types of negative impacts, the most commonly perceived being noise, underground water contamination and geological disruption. Associated variables that were statistically significant predictors of risk perception include demographic characteristics (age, gender, education), environmental awareness level, landslide experience, awareness of past shale gas accidents, information sources, general knowledge about shale gas, and perspectives on whether negative impacts can be observed and controlled, along with trust in the central government and the petroleum company. Our findings implications are discussed, with the goal of informing both central and local authorities’ policy development in protecting local residents from risks of shale gas exploitation and better communicating risks to residents

    Pathways of change : shifting connectivities in the world city network, 2000-08

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    This is an empirical paper that measures and interprets changes in intercity relations at the global scale in the period 2000-08. It draws on the network model devised by the Globalization and World Cities (GaWC) research group to measure global connectivities for 132 cities across the world in 2000 and 2008. The measurements for both years are adjusted so that a coherent set of services/cities is used. A range of statistical techniques is used to explore these changes at the city level and the regional scale. The most notable changes are: the general rise of connectivity in the world city network; the loss of global connectivity of US and sub-Saharan African cities (Los Angeles, San Francisco and Miami in particular); and, the gain in global connectivity of south Asian, Chinese and eastern European cities (Shanghai, Beijing and Moscow in particular)

    The changing geography of globalized service provision, 2000-2008

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    This empirical paper maps changes in the global geography of advanced producer service provision across major cities in the 2000-2008 period. The analyses are based on a systematic assessment of geographical shifts in the office networks of leading firms in finance, management consultancy, accountancy, advertising and law, using measures of inter-city connectivity. It has been previously shown that there has been a general shift of these services from 'West to East'. In this paper, variations in the degree and pattern of this global shift among the different sectors are described and interpreted. The results point to an inherent complexity in economic globalization that is sometimes overlooked in general descriptions of the meta-process

    Molecular and morphological evidence for the identity of two nominal species of Astegopteryx (Hemiptera, Aphididae, Hormaphidinae)

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    The morphology of many insect species is usually influenced by environmental factors and therefore high phenotypic variation exists even within a species. This causes difficulty and uncertainty in species taxonomy, which can be remedied by using molecular data and integrative taxonomy. Astegopteryx bambusae and A. bambucifoliae are currently regarded as two closely related aphid species with similar bamboo hosts and overlapping distributions in the oriental region. However, in practice it is hard to distinguish between them. By incorporating molecular data from four mitochondrial and nuclear genes as well as morphological information from an extensive collection of live specimens, the present study indicates that A. bambucifoliae is a junior synonym of A. bambusae. The data also indicate that large-scale geographic patterns of population differentiation may exist within this species

    A new simplified and robust Surface Reflectance Estimation Method (SREM) for use over diverse land surfaces using multi-sensor data

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    Surface reflectance (SR) estimation is the most critical pre-processing step for deriving geophysical parameters in multi-sensor remote sensing. Most state-of-the-art SR estimation methods, such as the vector version of the Second Simulation of the Satellite Signal in the Solar Spectrum (6SV) Radiative Transfer (RT) model, depend on accurate information on aerosol and atmospheric gases. In this study, a Simplified and Robust Surface Reflectance Estimation Method (SREM) based on the equations from 6SV RT model, without integrating information of aerosol particles and atmospheric gasses, is proposed and tested using Landsat 5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper plus (ETM+), and Landsat 8 Operational Land Imager (OLI) data from 2000 to 2018. For evaluation purposes, (i) the SREM SR retrievals are validated against in-situ SR measurements collected by Analytical Spectral Devices (ASD) for the South Dakota State University (SDSU) site, USA (ii) cross-comparison between the SREM and Landsat spectral SR products, i.e., Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) and Landsat 8 Surface Reflectance Code (LaSRC), are conducted over 11 urban (2013-2018), 13 vegetated (2013-2018), and 11 desert/arid (2000 to 2018) sites located over different climatic zones at global scale, (iii) the performance of the SREM spectral SR retrievals for low to high aerosol loadings is evaluated, (iv) spatio-temporal cross-comparison is conducted for six Landsat paths/rows located in Asia, Africa, Europe, and the USA from 2013 to 2018 to consider a large variety of land surfaces and atmospheric conditions, (v) cross-comparison is also performed for the Normalized Difference Vegetation Index (NDVI), the Enhanced Vegetation Index (EVI), and the Soil Adjusted Vegetation Index (SAVI) calculated from both the SREM and Landsat SR data, (vi) the SREM is also applied to the Sentinel-2A and Moderate Resolution Imaging Spectrometer (MODIS) data to explore its applicability, and (vii) errors in the SR retrievals are reported using the Mean Bias Error (MBE), Root Mean Squared Deviation (RMSD) and Mean Systematic Error (MSE). Results depict significant and strong positive Pearson’s correlation (r), small MBE, RMSD, and MSE for each spectral band against in-situ ASD data and Landsat (LEDAPS and LaSRC) SR products. Consistency in SREM performance against Sentinel-2A (r = 0.994, MBE = - 0.009, and RMSD = 0.014) and MODIS (r = 0.925, MBE = 0.007, and RMSD = 0.014) data suggests that SREM can be applied to other multispectral satellites data. Overall, the findings demonstrate the potential and promise of SREM for use over diverse surfaces and under varying atmospheric conditions using multi-sensor data on a global scale
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