Publications by authors named "Xuguo Zhang"

Crop production is a large source of atmospheric ammonia (NH), which poses risks to air quality, human health and ecosystems. However, estimating global NH emissions from croplands is subject to uncertainties because of data limitations, thereby limiting the accurate identification of mitigation options and efficacy. Here we develop a machine learning model for generating crop-specific and spatially explicit NH emission factors globally (5-arcmin resolution) based on a compiled dataset of field observations.

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Due to the non-linearity in ozone (O) formation, reducing the emission of nitrogen oxides (NO) may increase O concentration. Given the counteractive O response to NO reduction, overall impact of air pollution controls can be ambiguous when the assessments focus on the changes in pollutant concentrations. In this study, a risk-based method was used to gauge the net effect of air pollution controls on mortality risk in the Beijing-Tianjin-Hebei (BTH) region during the 2022 Winter Olympics and Paralympics (WOP).

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Ultrahigh-resolution air quality models that resolve sharp gradients of pollutant concentrations benefit the assessment of human health impacts. Mitigating fine particulate matter (PM) concentrations over the past decade has triggered ozone (O) deterioration in China. Effective control of both pollutants remains poorly understood from an ultrahigh-resolution perspective.

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O pollution had been worsening in mainland China in the past decade, posing significant human health challenges. The NO control would trigger increasing O concentrations in response to a series of released China emission reduction policies. This study used sensitivity analysis methodology to explore the effectiveness of integrated sectoral emission control policies that have been expanded throughout China.

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Problems with PM pollution in the Pearl River Delta (PRD) have been significantly reduced since the Chinese government released a series of emission control policies including the strengthened controls in the 13 Five-Year Plan. This study assessed the efficacy of emission control measures using the Community Multiscale Air Quality (CMAQ) model to provide data-driven support to government decision making, which is becoming increasingly important. This study aimed to quantitatively evaluate the integrated results of proposed policies for controlling PM concentrations.

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A technique to determine the aerosol extinction-to-backscatter ratio (lidar ratio) as well as extinction and backscatter coefficients from simultaneous ground-based and space-borne lidar measurements is proposed. This technique can be applied in presence of more than one aerosol layer. To test the reliability of this technique, a numerical simulation has been performed.

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Pancreatic stellate cells (PSCs) produce the stromal reaction in pancreatic cancer (PC), and their interaction with cancer cells facilitates cancer progression. This study investigated the role of human PSCs (hPSCs) in the metastatic process and tumor angiogenesis using both in vivo (orthotopic model) and in vitro (cultured PSC and PC cells) approaches. A sex mismatch study (injection of male hPSCs plus female PC cells into the pancreas of female mice) was conducted to determine whether hPSCs accompany cancer cells to metastatic sites.

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Background And Aims: Administration of repeated lipopolysaccharide (LPS) injections in alcohol-fed rats leads to significant pancreatic injury including fibrosis. However, it remains unknown whether alcoholic (chronic) pancreatitis has the potential to regress when alcohol is withdrawn. The aims of the study were (1) to compare the effect of alcohol withdrawal/continuation on pancreatic acute injury and fibrosis; and (2) to assess the effects of alcohol ± LPS on pancreatic stellate cell (PSC) apoptosis in vivo and in vitro.

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Background: Pancreatic stellate cells (PSCs) play a critical role in pancreatic fibrosis. To date, human PSC biology has been studied using cancer- or inflammation-associated (pre-activated) PSCs, but an in vitro model of quiescent normal human PSCs (NhPSCs) has been lacking.

Aims: To (i) isolate and characterize quiescent NhPSCs, and (ii) evaluate the response of culture-activated NhPSCs to cytokines and LPS.

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A new method is proposed to analyze the effects of multiple scattering on simultaneously detected lidar returns for ground-based and space-borne lidars, and it is applied to a Monte Carlo-based simulation to test the feasibility of the new method. The experimental evidence of multiple scattering influences on both ground-based and space-borne lidar returns is presented. Monte Carlo-based evaluations of the multiple scattering parameters for the counter-looking lidar returns are separately obtained in order to correct the effective values of backscattering and extinction coefficients.

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