316 research outputs found

    Impact of HBeAg on the maturation and function of dendritic cells

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    AbstractObjectivesHBV infection typically leads to chronic hepatitis in newborns and some adults with weakened immune systems. The mechanisms by which virus escapes immunity remain undefined. Regulatory dendritic cells (DCregs) contributing to immune escape have been described. We wondered whether or not HBeAg as an immunomodulatory protein could induce DCreg which might subsequently result into HBV persistence.MethodsThe immunophenotyping, T-cell activation and cytokine production were analyzed in HBeAg-treated DCs from normal or cyclophosphamide (Cy)-induced immunocompromised mice.ResultsHBeAg tended to promote bone marrow derived DCs (BMDCs) from Cy-treated mice into CD11bhighPIR-B+ regulatory DCs exhibiting the lowest T-cell stimulatory capacity and interleukin (IL)-12p70 production compared with controls. Neutralization of IL-10 significantly inhibited the regulatory effect of these DCs on T-cell stimulation of mature DCs. After lipopolysaccharides (LPS) stimulation, marked phosphorylation of Akt was detected in HBeAg treated DCs from immunocompromised mice. Blocking the PI3K-Akt pathway by LY294002 led to an enhancement of IL-12 production. PI3K signalling pathway appears to be involved in the decreased IL-12 secretion by HBeAg treated DCs.ConclusionsThese findings suggest that HBeAg may program the generation of a new DC subset with regulatory capacity under the condition of immunosuppression, which may presumably contribute to the persistent HBV infection

    Research of the Impact of Heterogeneous Environmental Regulation on the Performance of China’s Manufacturing Enterprises

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    Promoting high-quality economic development with high-level ecological protection is one of the most important tasks in China’s new stage of development. The improvement of enterprise performance is the micro-foundation of high-quality economic development, while environmental regulations aim to reduce the negative effect of economic development on the environment. Consequently, the microeconomic effects of environmental regulation have received widespread attention in academia. Previous studies have emphasized the effect of environmental regulations on firm performance but have not reached a consensus and lack of insight on the combined effects of different types of environmental regulation. This study aims to fill this gap by considering the heterogeneity of environmental regulations and the effect of the interaction between heterogeneous environmental regulations on enterprise performance. To reveal the relationship between the different types of environmental regulations and the performance of manufacturing enterprises, and the possible impact mechanism, this study uses the fixed effect model to test the impact of different environmental regulations on the performance of manufacturing enterprises, the mediation effect model is used to check whether or not an environmental regulation affects the performance of manufacturing enterprises by improving the level of technological innovation of enterprises, and the moderating effect model is used to examine the impact of the interaction between different environmental regulations on the performance of manufacturing enterprises. The results show that command-and-control environmental regulation inhibits the performance improvement of manufacturing enterprises, while a market-based environmental regulation enhances performance by improving the technological innovation level of enterprises. Market-based environmental regulation will alleviate the disincentive effect of command-control environmental regulation on the performance of manufacturing enterprise

    Haze and inbound tourism: Empirical evidence from China

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    The impact of climate change on tourism has always been an important topic for research in the field of international tourism, and haze has been widely recognized as the primary negative factor affecting the development of inbound tourism in China. In this study, we first conduct a theoretical analysis of the mechanism through which haze influences the tourism industry, and then we empirically analyze the impact on China’s inbound tourism using surface particulate matter (PM2.5) concentrations as a proxy for haze, based on provincial panel data from 1998 to 2016. The empirical results show that haze not only has an inhibitory effect on inbound tourism, but also significantly reduces the average length of stay of international tourists. In addition, while there are significant regional differences in the crowding-out effect of haze pollution on inbound tourism, the effect varies depending on the origin of inbound tourists, exhibiting the greatest negative impact on inbound tourism from Taiwan and the smallest from foreign countries. Our research highlights that haze pollution can led to the change of human tourism behavior which enrich the literature on tourism and haze

    Engineering Properties of Sweet Potato Starch for Industrial Applications by Biotechnological Techniques Including Genome Editing

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    Sweet potato (Ipomoea batatas) is one of the largest food crops in the world. Due to its abundance of starch, sweet potato is a valuable ingredient in food derivatives, dietary supplements, and industrial raw materials. In addition, due to its ability to adapt to a wide range of harsh climate and soil conditions, sweet potato is a crop that copes well with the environmental stresses caused by climate change. However, due to the complexity of the sweet potato genome and the long breeding cycle, our ability to modify sweet potato starch is limited. In this review, we cover the recent development in sweet potato breeding, understanding of starch properties, and the progress in sweet potato genomics. We describe the applicational values of sweet potato starch in food, industrial products, and biofuel, in addition to the effects of starch properties in different industrial applications. We also explore the possibility of manipulating starch properties through biotechnological means, such as the CRISPR/Cas-based genome editing. The ability to target the genome with precision provides new opportunities for reducing breeding time, increasing yield, and optimizing the starch properties of sweet potatoes

    Tree ring δ18O reveals no long-term change of atmospheric water demand since 1800 in the northern Great Hinggan Mountains, China

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    Global warming will significantly increase transpirational water demand, which could dramatically affect plant physiology and carbon and water budgets. Tree ring δ18O is a potential index of the leaf-to-air vapor-pressure deficit (VPD) and therefore has great potential for long-term climatic reconstruction. Here we developed δ18O chronologies of two dominant native trees, Dahurian larch (Larix gmelinii Rupr.) and Mongolian pine (Pinus sylvestris var. mongolica), from a permafrost region in the Great Hinggan Mountains of northeastern China. We found that the July–August VPD and relative humidity were the dominant factors that controlled tree ring δ18O in the study region, indicating strong regulation of stomatal conductance. Based on the larch and pine tree ring δ18O chronologies, we developed a reliable summer (July–August) VPD reconstruction since 1800. Warming growing season temperatures increase transpiration and enrich cellulose 18O, but precipitation seemed to be the most important influence on VPD changes in this cold region. Periods with stronger transpirational demand occurred around the 1850s, from 1914 to 1925, and from 2005 to 2010. However, we found no overall long-term increasing or decreasing trends for VPD since 1800, suggesting that despite the increasing temperatures and thawing permafrost throughout the region, forest transpirational demand has not increased significantly during the past two centuries. Under current climatic conditions, VPD did not limit growth of larch and pine, even during extremely drought years. Our findings will support more realistic evaluations and reliable predictions of the potential influences of ongoing climatic change on carbon and water cycles and on forest dynamics in permafrost regions

    Effects of Nanoparticle Size and Radiation Energy on Copper-Cysteamine Nanoparticles for X-ray Induced Photodynamic Therapy

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    The Copper-cysteamine (Cu-Cy) nanoparticle is a novel sensitizer with a potential to increase the effectiveness of radiation therapy for cancer treatment. In this work, the effect of nanoparticle size and the energy of X-rays on the effectiveness of radiation therapy are investigated. The effect of the particle size on their performance is very complicated. The nanoparticles with an average size of 300 nm have the most intense photoluminescence, the nanoparticles with the average size of 100 nm have the most reactive oxygen species production upon X-ray irradiation, while the nanoparticles with the average size of 40 nm have the best outcome in the tumor suppression in mice upon X-ray irradiation. For energy, 90 kVp radiation resulted in smaller tumor sizes than 250 kVp or 350 kVp radiation energies. Overall, knowledge of the effect of nanoparticle size and radiation energy on radiation therapy outcomes could be useful for future applications of Cu-Cy nanoparticles

    Asymmetric response of soil methane uptake rate to land degradation and restoration: Data synthesis

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    Land degradation and restoration profoundly affect soil CH(4)uptake capacity in terrestrial ecosystems. However, a comprehensive assessment of the response of soil CH(4)uptake to land degradation and restoration at global scale is not available. Here, we present a global meta-analysis with a database of 228 observations from 83 studies to investigate the effects of land degradation and restoration on the capacity of soil CH(4)uptake. We found that land degradation significantly decreased the capacity of soil CH(4)uptake, except the conversion of pasture to cropland where the soil CH(4)uptake rate showed no response. In contrast, all types of land restoration significantly increased the capacity of soil CH(4)uptake. Interestingly, the response of soil CH(4)uptake rate to land degradation and restoration was asymmetric: the increased soil CH(4)uptake rate in response to the land restoration was smaller compared to the decrease in CH(4)uptake rate induced by the land degradation. The effect of land degradation on soil CH(4)uptake rate was not dependent on the time since land use change, but the CH(4)sink strength increased with the time since land restoration. The response of soil CH(4)uptake rate to both land degradation and restoration was predominantly regulated by changes in the soil water-filled pore space, soil bulk density, and pH, whereas alterations in the substrate quantity and quality had negligible effect. Additionally, the effects of land degradation and restoration on soil CH(4)uptake were strongly related to the mean annual precipitation and soil texture. Overall, our results provide novel insights for understanding of how land degradation and restoration can affect the CH(4)sink strength of upland soils, and more importantly, our findings are beneficial to take measures to enhance the potential of soil CH(4)uptake in response to global land use change

    Factors affecting the production of sugarcane yield and sucrose accumulation: suggested potential biological solutions

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    Environmental stresses are the main constraints on agricultural productivity and food security worldwide. This issue is worsened by abrupt and severe changes in global climate. The formation of sugarcane yield and the accumulation of sucrose are significantly influenced by biotic and abiotic stresses. Understanding the biochemical, physiological, and environmental phenomena associated with these stresses is essential to increase crop production. This review explores the effect of environmental factors on sucrose content and sugarcane yield and highlights the negative effects of insufficient water supply, temperature fluctuations, insect pests, and diseases. This article also explains the mechanism of reactive oxygen species (ROS), the role of different metabolites under environmental stresses, and highlights the function of environmental stress-related resistance genes in sugarcane. This review further discusses sugarcane crop improvement approaches, with a focus on endophytic mechanism and consortium endophyte application in sugarcane plants. Endophytes are vital in plant defense; they produce bioactive molecules that act as biocontrol agents to enhance plant immune systems and modify environmental responses through interaction with plants. This review provides an overview of internal mechanisms to enhance sugarcane plant growth and environmental resistance and offers new ideas for improving sugarcane plant fitness and crop productivity

    Prognostic values of ALDOB expression and 18F-FDG PET/CT in hepatocellular carcinoma

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    PurposeThe glycolytic enzyme fructose 1,6-bisphosphate aldolase B (ALDOB) is aberrantly expressed and impacts the prognosis in hepatocellular carcinoma (HCC). Hepatic ALDOB loss leads to paradoxical upregulation of glucose metabolism, favoring hepatocellular carcinogenesis. Nevertheless, the relationship between ALDOB expression and 18F-fluorodeoxyglucose (18F-FDG) uptake, and their effects on HCC prognosis remain unclear. We evaluated whether ALDOB expression is associated with 18F-FDG uptake and their impacts on HCC prognosis prediction.MethodsChanges in ALDOB expression levels and the prognostic values in HCC were analyzed using data from The Cancer Genome Atlas (TCGA) database. Ultimately, 34 patients with HCC who underwent 18F-FDG positron emission tomography/computed tomography (PET/CT) preoperatively were enrolled in this retrospective study. ALDOB expression was determined using immunohistochemistry (IHC) staining, and the maximum standardized uptake value (SUVmax) of HCC was calculated from the 18F-FDG PET/CT scans. The relationship between ALDOB expression and SUVmax was examined, and their impacts on overall survival were evaluated using Cox proportional hazards models and Kaplan–Meier survival analysis. ALDOB overexpression in HUH7 and 7721 cells was used to analyze its role in tumor metabolism.ResultsAccording to TCGA database, the ALDOB mRNA level was downregulated in HCC compared to normal tissue, and significantly shortened overall survival in HCC patients. ALDOB protein expression was similarly decreased in IHC findings in HCC than that in adjacent normal tissues (P<0.05) and was significantly associated with tumor size (P<0.001), high tumor-node-metastasis stage (P=0.022), and elevated SUVmax (P=0.009). ALDOB expression in HCC was inversely correlated with SUVmax (r=-0.454; P=0.012), and the optimal SUVmax cutoff value for predicting its expression was 4.15. Prognostically, low ALDOB expression or SUVmax ≥3.9 indicated shorter overall survival time in HCC. Moreover, COX regression analysis suggested high SUVmax as an independent prognostic risk factor for HCC (P=0.036). HCC patients with negative ALDOB expression and positive SUVmax (≥3.9) were correlated with worse prognosis. ALDOB overexpression in HCC cells significantly decreases 18F-FDG uptake and lactate production.ConclusionSUVmax in HCC patients is inversely correlated with ALDOB expression, and 18F-FDG PET/CT may be useful for ALDOB status prediction. The combined use of ALDOB expression and 18F-FDG PET/CT data can provide additional information on disease prognosis in HCC patients
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