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1.
Plant Dis ; 2024 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-38679599

RESUMO

Cardamine violifolia, also called Cardamine hupingshanensis, is an economically important medicinal plant renowned for accumulating selenium (Guo et al., 2022). Selenium is an essential trace element with anti-oxidant, anti-inflammatory, anti-cancer, and immune regulatory functions. In July 2023, an outbreak of powdery mildew was detected, infecting the leaves of numerous C. violifolia plants in Enshi (30°11'5.27''N; 109°48'48.45''E), Hubei Province, China. This disease caused severe damage to plant leaves and stems, starting as individual spots and merging into a large mold that covers the entire leaf. It affected nearly 25% all C. violifolia plants, resulting in significant yield loss, disruption of normal metabolism, and premature aging. The lower leaf blades and underside of the leaves were particularly vulnerable. The affected leaves were collected and subjected to morphological diagnostic analysis (Mori et al., 2000) (Fig. S1). The powdery mildew species aggressively spread throughout the leaves, pedicels, and pods, persisting until present and often covering the entire surface. The conidiophores were upright, cylindrical, composed of 3 to 4 cells, and measured 92.3 ± 12.9 × 9.2 ± 0.6 µm (n = 30). Conidial pedicels had 21.6 ± 3.4 µm (n = 50) long cylindrical podocytes. The monoconidia were columnar or barrel-columnar, 30.60-55.59 × 9.11-20.00 µm in size. Conidia lacked an obvious cellulose body. The bud tubes formed from the end of conidia, and papillary appressoria developed on the epiphytic mycelia. ITS region sequences were amplified using the specific powdery mildew universal primers ITS1 (5'-TCCGTAGGTGAACCTGCGG-3'), PM6 (5'-GYCRCYCTGTCGCGAG-3') for partial sequences of 18S and 28S ribosomal DNA genes (Takamatsu et al., 2001). The sequence was deposited in the GenBank under the accession number OR506156 and aligned with available sequences on NCBI, which were 99.2%(528/532) identical to the E. cruciferarum (MT309701, MF192845, and KY660929) sequences (Fig. S2). The ITS sequence from GenBank was used to conduct maximum likelihood phylogenetic analysis using MEGA 11.0. The analysis results showed both the strain and E. cruciferarum clustered on the same branch. To confirm Koch's postulates, pathogenicity testing was carried out using an illuminating incubator. Infected leaves were attached to healthy leaves of C. violifolia seedlings (n=8). All the plants were incubated under 25℃ and >80% relative humidity. After one month, all inoculated plants presented the same symptoms as those initially observed in the field. Morphological and molecular analysis confirmed the isolated fungi's identity as the same pathogen. Therefore, C. violifolia is a suitable host for E. cruciferarum in China. The growers must be informed of these findings to prevent serious economic losses caused by this pathogenic white powder and to prepare for proper management practices. To our knowledge, this is the first report of E. cruciferarum infecting C. violifolia in China.

2.
Heliyon ; 10(4): e25884, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38390149

RESUMO

Background: Human health is seriously threatened by particulate matter (PM) pollution, which is a major environmental problem. A better indicator of biological responses to PM exposure than its mass alone is the PM "oxidative potential (OP)," or ability to oxidize target molecules. When reactive oxygen species (ROS) are generated in the OP in excess of the antioxidant capacity of body due to PM components such metals and organic species, it causes inflammation, deoxyribonucleic acid (DNA), proteins, and lipids damage. Method: The samples of fine particulate matter (PM2.5) are collected from the brick kiln site and the roadside in Lahore, Pakistan. The organic carbon (OC) and elemental carbon (EC) were estimated by carbon analyzer (DRI 2001A) using the thermal/optical transmittance (TOT) protocol. The water-soluble organic carbon (WSOC) concentration was determined using a total organic carbon analyzer (Shimadzu TOC-L CPN). Ion chromatography (Dionex ICS-900) with a conductivity detector was used to analyze the water-soluble anions (Cl-, NO3-, and SO42-) and cations (NH4+, Na+, K+, Mg2+, and Ca2+). Inductively coupled plasma-mass spectrometry (iCAP TQ ICP-MS, Thermo Scientific) was used to determine the concentrations of metals in the solution. The dithiothreitol (DTT) consumption rate was calculated using a spectrophotometer at a wavelength of 412 nm. Results: The mean concentrations of PM2.5 at the brick kiln site and roadside reported are 509.3 ± 32.3 µg/m3 and 467.5 ± 24.9 µg/m3, and the average OC/EC ratio is 1.9 ± 0.4 and 2.1 ± 0.1. primary organic carbon (POC) contributed more to OC than secondary organic carbon (SOC), which indicated the dominance of primary combustion sources. The anion equivalent (AE) to cation equivalent (CE) ratio indicated that PM2.5 is acidic at both sites due to the dominance of NO3- and SO42-. The DTT consumption rate normalized by PM2.5 mass (DTTm) and DTT consumption rate normalized by air volume (DTTv) of PM2.5 at the roadside samples are higher than at the brick kiln site due to the higher contribution of ionic species to the mass of PM2.5. Carbonaceous species of PM2.5 at both sampling sites are significantly correlated with DTTv of PM2.5, while metallic species behaved differently. The incremental lifetime cancer risk (ILCR) values (lung cancer) of As and Cr at both sampling sites, while the ILCR value of Cd at the roadside samples is exceeding the permissible limits for adults and children. The lifetime average daily dose (LADD) value for adults is higher than that for children, indicating that children are less vulnerable to metals. Conclusion: The concentration of PM2.5 at both sampling sites were exceeding the permissible limits of Pakistan' National Environmental Quality Standard (NEQS) and posing risk to the health of the local population. The POC and SOC contribution to OC at the brick kiln site and roadside in Lahore were 84.6%, 15.4% and 84.4%, 15.6%. POC at both sampling sites were the dominant carbon species indicating the dominance of primary combustion sources. The residence of Lahore poses the lung cancer risk due to Cr, As, and Cd at both sampling sites. The results of this study provide important data and evidence for further evaluation of the potential health risks of PM2.5 from brick kiln site and road side in Pakistan and formulation of efficient air-pollution control measures.

4.
BMC Endocr Disord ; 22(1): 252, 2022 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-36266640

RESUMO

OBJECTIVE: The incidence of papillary thyroid cancer (PTC) concomitant with Hashimoto's thyroiditis (HT) is gradually increasing over the past decades. This study aims to identify differentially expressed lncRNAs between tumor tissues of PTC with or without HT and further to confer a better understanding of lncRNA-based competing endogenous RNA (ceRNA) network in PTC with HT. METHODS: GSE138198 containing tissue mRNA data and GSE192560 containing lncRNA data were utilized to perform differentially expression analysis. The ceRNA network was constructed based on miRNA-mRNA interactions merging with lncRNA-microRNA interactions. Functional enrichment analysis and protein-protein interaction (PPI) analysis were performed. The mRNA levels of core genes in the PPI analysis in tumor tissues collected from 112 PTC patients including 35 cases coexistent with HT were determined by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: A total of 57 genes and 40 lncRNAs, with value of |log2 fold change (FC)|≥ 1 and the adjusted P-value < 0.05, were deemed as differentially expressed genes and lncRNAs between PTC with and without HT. The pathways most significantly enriched by differentially expressed genes between PTC with and without HT were viral protein interaction with cytokine and cytokine receptor and cytokine-cytokine receptor interaction. CXCL10, CXCL9, CCL5, FCGR3A, and CCR2 owned degree values not less than 10 were deemed as core genes differentially expressed between PTC with and without HT. A total of 76 pairs of lncRNA-miRNA-mRNA ceRNA were obtained. Results of qRT-PCR partially demonstrated the bioinformatics results that the mRNA levels of CXCL10, CXCL9, CCL5, and CCR2 were remarkably elevated in tumor tissues collected from PTC patients coexistent with HT than those without HT (P < 0.001). CONCLUSION: Our study offers a better understanding of the lncRNA-related ceRNA network involved in PTC with HT, providing novel key genes associated with PTC coexistent with HT.


Assuntos
Doença de Hashimoto , MicroRNAs , RNA Longo não Codificante , Neoplasias da Glândula Tireoide , Humanos , Câncer Papilífero da Tireoide/complicações , Câncer Papilífero da Tireoide/genética , Câncer Papilífero da Tireoide/metabolismo , RNA Longo não Codificante/genética , Doença de Hashimoto/complicações , Doença de Hashimoto/genética , Doença de Hashimoto/metabolismo , MicroRNAs/genética , RNA Mensageiro/genética , Neoplasias da Glândula Tireoide/complicações , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/patologia , Citocinas , Receptores de Citocinas , Proteínas Virais
5.
Colloids Surf B Biointerfaces ; 217: 112655, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35785715

RESUMO

Treatment of late-stage lung cancer has witnessed limited advances. In contrast to the tremendous efforts toward improving adaptive immunity, approaches to modulating innate immunity are relatively immature. As important innate immune cells, tumor-associated macrophages (TAMs) account for a substantial fraction of tumor-infiltrating lymphocytes, which not only reverses the immune-suppressive tumor microenvironment but also facilitates an adaptive immune response. In this study, we developed a tumor-specific MMP-2-responsive CD47 blockage (TMCB) strategy to enable effective cancer immunotherapy. Briefly, the matrix metalloproteinase-2 (MMP-2)-responsive self-assembly peptide specifically recognizes CD47, which is highly expressed in lung tumor cells. Second, the MMP-2-responsive self-assembly peptide is efficiently cleaved by MMP-2, which is overexpressed in the tumor microenvironment. Finally, the generated residual peptide naturally self-assembles into peptide-based nanofibers. The in situ constructed nanofibers inhibit the canonical CD47 "Do not eat me" signal expressed on tumor cells to promote phagocytosis of tumor cells by macrophages, which further induces effective antigen presentation and initiates T cell-mediated adaptive immune responses to inhibit tumor growth. Thus, we described a peptide-based TMCB strategy that induces both innate and adaptive immune systems to inhibit tumor growth.


Assuntos
Antígeno CD47 , Neoplasias , Humanos , Imunoterapia , Metaloproteinase 2 da Matriz , Neoplasias/patologia , Neoplasias/terapia , Peptídeos , Fagocitose , Microambiente Tumoral
6.
Int J Chron Obstruct Pulmon Dis ; 17: 1537-1552, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35811742

RESUMO

Purpose: Pulmonary surfactant proteins A (SP-A) and D (SP-D) are lectins, involved in host defense and regulation of pulmonary inflammatory response. However, studies on the assessment of COPD progress are limited. Patients and Methods: Pulmonary surfactant proteins were obtained from the COPD mouse model induced by cigarette and lipopolysaccharide, and the specimens of peripheral blood and bronchoalveolar lavage (BALF) in COPD populations. H&E staining and RT-PCR were performed to demonstrate the successfully established of the mouse model. The expression of SP-A and SP-D in mice was detected by Western Blot and immunohistochemistry, while the proteins in human samples were measured by ELISA. Pulmonary function test, inflammatory factors (CRP, WBC, NLR, PCT, EOS, PLT), dyspnea index score (mMRC and CAT), length of hospital stay, incidence of complications and ventilator use were collected to assess airway remodeling and progression of COPD. Results: COPD model mice with emphysema and airway wall thickening were more prone to have decreased SP-A, SP-D and increased TNF-α, TGF-ß, and NF-kb in lung tissue. In humans, SP-A and SP-D decreased in BALF, but increased in serum. The serum SP-A and SP-D were negatively correlated with FVC, FEV1, FEV1/FVC, and positively correlated with CRP, WBC, NLR, mMRC and CAT scores (P < 0.05, respectively). The lower the SP-A and SP-D in BALF, the worse the lung function and the increased probability of complications and ventilator use. Moreover, the same trend emerged in COPD patients grouped according to GOLD severity grade (Gold 1-2 group vs Gold 3-4 group). The worse the patient's condition, the more pronounced the change. Conclusion: This study suggests that SP-A and SP-D may be related to the progression and prognostic evaluation of COPD in terms of airway remodeling, inflammatory response and clinical symptoms, and emphasizes the necessity of future studies of surfactant protein markers in COPD.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Surfactantes Pulmonares , Remodelação das Vias Aéreas , Animais , Biomarcadores , Camundongos , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Proteína A Associada a Surfactante Pulmonar/uso terapêutico , Proteína D Associada a Surfactante Pulmonar/análise , Proteína D Associada a Surfactante Pulmonar/uso terapêutico , Surfactantes Pulmonares/uso terapêutico
7.
Front Immunol ; 13: 740513, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35350787

RESUMO

Objective: This study aims to identify clinically relevant diagnostic biomarkers in chronic obstructive pulmonary disease (COPD) while exploring how immune cell infiltration contributes towards COPD pathogenesis. Methods: The GEO database provided two human COPD gene expression datasets (GSE38974 and GSE76925; n=134) along with the relevant controls (n=49) for differentially expressed gene (DEG) analyses. Candidate biomarkers were identified using the support vector machine recursive feature elimination (SVM-RFE) analysis and the LASSO regression model. The discriminatory ability was determined using the area under the receiver operating characteristic curve (AUC) values. These candidate biomarkers were characterized in the GSE106986 dataset (14 COPD patients and 5 controls) in terms of their respective diagnostic values and expression levels. The CIBERSORT program was used to estimate patterns of tissue infiltration of 22 types of immune cells. Furthermore, the in vivo and in vitro model of COPD was established using cigarette smoke extract (CSE) to validated the bioinformatics results. Results: 80 genes were identified via DEG analysis that were primarily involved in cellular amino acid and metabolic processes, regulation of telomerase activity and phagocytosis, antigen processing and MHC class I-mediated peptide antigen presentation, and other biological processes. LASSO and SVM-RFE were used to further characterize the candidate diagnostic markers for COPD, SLC27A3, and STAU1. SLC27A3 and STAU1 were found to be diagnostic markers of COPD in the metadata cohort (AUC=0.734, AUC=0.745). Their relevance in COPD were validated in the GSE106986 dataset (AUC=0.900 AUC=0.971). Subsequent analysis of immune cell infiltration discovered an association between SLC27A3 and STAU1 with resting NK cells, plasma cells, eosinophils, activated mast cells, memory B cells, CD8+, CD4+, and helper follicular T-cells. The expressions of SLC27A3 and STAU1 were upregulated in COPD models both in vivo and in vitro. Immune infiltration activation was observed in COPD models, accompanied by the enhanced expression of SLC27A3 and STAU1. Whereas, the knockdown of SLC27A3 or STAU1 attenuated the effect of CSE on BEAS-2B cells. Conclusion: STUA1 and SLC27A3 are valuable diagnostic biomarkers of COPD. COPD pathogenesis is heavily influenced by patterns of immune cell infiltration. This study provides a molecular biology insight into COPD occurrence and in exploring new therapeutic means useful in COPD.


Assuntos
Genes MHC Classe I , Doença Pulmonar Obstrutiva Crônica , Algoritmos , Biomarcadores , Proteínas do Citoesqueleto/genética , Humanos , Aprendizado de Máquina , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Doença Pulmonar Obstrutiva Crônica/genética , Proteínas de Ligação a RNA/genética
8.
Radiol Case Rep ; 16(11): 3389-3391, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34504631

RESUMO

Sparganosis is a rare disease caused by the infestation of the plerocercoid tapeworm larva of the genus Spirometra. Human sparganosis is most commonly encountered in subcutaneous fat areas of the abdomen, limbs, and genitourinary tract. Breast sparganosis occur very rarely, accounting for less than 2% of total human sparganosis cases. Because of the disease's rarity, clinical suspicion is essential to reach the diagnosis of breast sparganosis. We present a case of mammary sparganosis in a 58 year-old woman on the ultrasonographic findings. The patient had a painless breast lump with a history of drinking impure water. On ultrasonography (US), we noted four masses, the largest lesion was suspected as sparganosis, and others tended to be benign lesions. The patient was treated following excisions by a US guided Vacuum-assisted breast biopsy system (VABB). The final diagnosis of all lesions was sparganosis.

9.
Front Oncol ; 11: 705869, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34277450

RESUMO

BACKGROUND: A detailed means of prognostic stratification in patients with non-small cell lung cancer (NSCLC) is urgently needed to support individualized treatment plans. Recently, microRNAs (miRNAs) have been used as biomarkers due to their previously reported prognostic roles in cancer. This study aimed to construct an immune-related miRNA signature that effectively predicts NSCLC patient prognosis. METHODS: The miRNAs and mRNA expression and mutation data of NSCLC was obtained from The Cancer Genome Atlas (TCGA). Immune-associated miRNAs were identified using immune scores calculated by the ESTIMATE algorithm. LASSO-penalized multivariate survival models were using for development of a tumor immune-related miRNA signature (TIM-Sig), which was evaluated in several public cohorts from the Gene Expression Omnibus (GEO) and the CellMiner database. The miRTarBase was used for constructing the miRNA-target interactions. RESULTS: The TIM-Sig, including 10 immune-related miRNAs, was constructed and successfully predicted overall survival (OS) in the validation cohorts. TIM-Sig score negatively correlated with CD8+ T cell infiltration, IFN-γ expression, CYT activity, and tumor mutation burden. The correlation between TIM-Sig score and genomic mutation and cancer chemotherapeutics was also evaluated. A miRNA-target network of 10 miRNAs in TIM-Sig was constructed. Further analysis revealed that these target genes showed prognostic value in both lung squamous cell carcinoma and adenocarcinoma. CONCLUSIONS: We concluded that the immune-related miRNAs demonstrated a potential value in clinical prognosis.

10.
J Environ Sci (China) ; 102: 148-158, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33637240

RESUMO

The chemical characteristics, oxidative potential, and sources of PM2.5 were analyzed at the urban sites of Lahore and Peshawar, Pakistan in February 2019. Carbonaceous species, water soluble ions, and metal elements were measured to investigate the chemical composition and sources of PM2.5. The dithiothreitol (DTT) consumption rate was measured to evaluate the oxidative potential of PM2.5. Both cities showed a high exposure risk of PM2.5 regarding its oxidative potential (DTTv). Carbonaceous and some of the elemental species of PM2.5 correlated well with DTTv in both Lahore and Peshawar. Besides, the DTTv of PM2.5 in Lahore showed significant positive correlation with most of the measured water soluble ions, however, ions were DTT-inactive in Peshawar. Due to the higher proportions of carbonaceous species and metal elements, Peshawar showed higher mass-normalized DTT activity of PM2.5 compared to Lahore although the average PM2.5 concentration in Peshawar was lower. The high concentrations of toxic metals also posed serious non-carcinogenic and carcinogenic risks to the residents of both cities. Principle component analysis coupled with multiple linear regression was applied to investigate different source contributions to PM2.5 and its oxidative potential. Mixed sources of traffic and road dust resuspension and coal combustion, direct vehicle emission, and biomass burning and formation of secondary aerosol were identified as the major sources of PM2.5 in both cities. The findings of this study provide important data for evaluation of the potential health risks of PM2.5 and for formulation of efficient control strategies in major cities of Pakistan.


Assuntos
Poluentes Atmosféricos , Material Particulado , Poluentes Atmosféricos/análise , Cidades , Monitoramento Ambiental , Estresse Oxidativo , Paquistão , Material Particulado/análise , Estações do Ano , Emissões de Veículos/análise
12.
J Cell Mol Med ; 24(24): 14608-14618, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33184998

RESUMO

Growing evidence has highlighted the immune response as an important feature of carcinogenesis and therapeutic efficacy in non-small cell lung cancer (NSCLC). This study focused on the characterization of immune infiltration profiling in patients with NSCLC and its correlation with survival outcome. All TCGA samples were divided into three heterogeneous clusters based on immune cell profiles: cluster 1 ('low infiltration' cluster), cluster 2 ('heterogeneous infiltration' cluster) and cluster 3 ('high infiltration' cluster). The immune cells were responsible for a significantly favourable prognosis for the 'high infiltration' community. Cluster 1 had the lowest cytotoxic activity, tumour-infiltrating lymphocytes and interferon-gamma (IFN-γ), as well as immune checkpoint molecules expressions. In addition, MHC-I and immune co-stimulator were also found to have lower cluster 1 expressions, indicating a possible immune escape mechanism. A total of 43 differentially expressed genes (DEGs) that overlapped among the groups were determined based on three clusters. Finally, based on a univariate Cox regression model, prognostic immune-related genes were identified and combined to construct a risk score model able to predict overall survival (OS) rates in the validation datasets.


Assuntos
Biomarcadores Tumorais , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Microambiente Tumoral , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Biologia Computacional/métodos , Bases de Dados Genéticas , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/mortalidade , Fenótipo , Prognóstico , Reprodutibilidade dos Testes , Transcriptoma , Microambiente Tumoral/genética , Microambiente Tumoral/imunologia
13.
J Biol Chem ; 295(13): 4252-4264, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-32075911

RESUMO

SAM and HD domain-containing protein 1 (SAMHD1) is a host factor that restricts reverse transcription of lentiviruses such as HIV in myeloid cells and resting T cells through its dNTP triphosphohydrolase (dNTPase) activity. Lentiviruses counteract this restriction by expressing the accessory protein Vpx or Vpr, which targets SAMHD1 for proteasomal degradation. SAMHD1 is conserved among mammals, and the feline and bovine SAMHD1 proteins (fSAM and bSAM) restrict lentiviruses by reducing cellular dNTP concentrations. However, the functional regions of fSAM and bSAM that are required for their biological functions are not well-characterized. Here, to establish alternative models to investigate SAMHD1 in vivo, we studied the restriction profile of fSAM and bSAM against different primate lentiviruses. We found that both fSAM and bSAM strongly restrict primate lentiviruses and that Vpx induces the proteasomal degradation of both fSAM and bSAM. Further investigation identified one and five amino acid sites in the C-terminal domain (CTD) of fSAM and bSAM, respectively, that are required for Vpx-mediated degradation. We also found that the CTD of bSAM is directly involved in mediating bSAM's antiviral activity by regulating dNTPase activity, whereas the CTD of fSAM is not. Our results suggest that the CTDs of fSAM and bSAM have important roles in their antiviral functions. These findings advance our understanding of the mechanism of fSAM- and bSAM-mediated viral restriction and might inform strategies for improving HIV animal models.


Assuntos
HIV/genética , Lentivirus/genética , Transcrição Reversa/genética , Proteína 1 com Domínio SAM e Domínio HD/genética , Animais , Gatos , Bovinos , Células HEK293 , HIV/patogenicidade , Interações Hospedeiro-Patógeno/genética , Humanos , Lentivirus/patogenicidade , Células Mieloides/virologia , Domínios Proteicos/genética , Proteína 1 com Domínio SAM e Domínio HD/química , Linfócitos T/virologia , Replicação Viral/genética
14.
Environ Pollut ; 245: 853-863, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30502714

RESUMO

Based on the ground-measurements and MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications, Version 2) reanalysis data, the temporal-spatial variation of black carbon (BC) in Beijing and the affecting factors were investigated. According to the ground-measured BC concentration in November months of 2014, 2015 and 2016, the before-heating period in November 2014 showed the lowest BC concentration as a result of the efficient emission controls for the Asia-Pacific Economic Cooperation (APEC) meeting. Except for November 2014, the BC mass concentration during the heating periods was notably lower than the before-heating periods in November 2015 and 2016. Wind speed and relative humidity appeared to be two important meteorological parameters affecting BC pollution. The MERRA-2 BC concentration was validated through comparison with the continuous ground BC measurements in 2015 and 2016, affirming its reliability in demonstrating the large scale and long term variations of the ground BC concentration. The MERRA-2 BC spatial distribution, the potential source regions determined by concentration weighted trajectory (CWT) analysis, and the regional emission inventories were combined to reveal the potential source regions and source types of BC in Beijing. Transportation emission in Beijing and residential emissions in the neighboring regions such as Hebei appeared to be important sources of BC in Beijing. According to the historical trends of MERRA-2 BC concentration and typical fossil fuel consumption (1980-2017), local coal and coke are no longer the major factor affecting the BC concentration, instead, liquid fuels such as gasoline, kerosene, and diesel may highly contribute to the BC pollution in Beijing in recent years. Regional transport of BC may have also contributed to the loading of BC in Beijing. Open biomass burning may be a non-negligible factor for the short-term variation of BC in the atmosphere.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Fuligem/análise , Poluição do Ar/estatística & dados numéricos , Ásia , Atmosfera/análise , Pequim , Biomassa , Carbono/análise , China , Carvão Mineral/análise , Combustíveis Fósseis/análise , Reprodutibilidade dos Testes , Estudos Retrospectivos , Fuligem/química , Vento
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