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1.
Int Immunopharmacol ; 136: 112340, 2024 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-38820962

RESUMO

BACKGROUND: Adenosine deaminase acting on RNA 1 (ADAR1) is an RNA-editing enzyme that significantly impacts cancer progression and various biological processes. The expression of ADAR1 mRNA has been examined in multiple cancer types using The Cancer Genome Atlas (TCGA) dataset, revealing distinct patterns in kidney chromophobe (KICH), kidney renal clear cell carcinoma (KIRC), kidney renal papillary cell carcinoma (KIRP), and liver hepatocellular carcinoma (LIHC) compared to normal controls. However, the reasons for these differential expressions remain unclear. METHODS: In this study, we performed RT-PCR and western blotting (WB) to validate ADAR1 expression patterns in clinical tissue samples. Survival analysis and immune microenvironment analysis (including immune score and stromal score) were conducted using TCGA data to determine the specific cell types associated with ADAR1, as well as the key genes in those cell types. The relationship between ADAR1 and specific cell types' key genes was verified by immunohistochemistry (IHC), using clinical liver and kidney cancer samples. RESULTS: Our validation analysis revealed that ADAR1 expression was downregulated in KICH, KIRC, and KIRP, while upregulated in LIHC compared to normal tissues. Notably, a significant correlation was found between ADAR1 mRNA expression and patient prognosis, particularly in KIRC, KIRP, and LIHC. Interestingly, we observed a positive correlation between ADAR1 expression and stromal scores in KIRC, whereas a negative correlation was observed in LIHC. Cell type analysis highlighted distinct relationships between ADAR1 expression and the two stromal cell types, blood endothelial cells (BECs) and lymphatic endothelial cells (LECs), and further determined the signature gene claudin-5 (CLDN5), in KIRC and LIHC. Moreover, ADAR1 was inversely related with CLDN5 in KIRC (n = 26) and LIHC (n = 30) samples, verified via IHC. CONCLUSIONS: ADAR1 plays contrasting roles in LIHC and KIRC, associated with the enrichment of BECs and LECs within tumors. This study sheds light on the significant roles of stromal cells within the complex tumor microenvironment (TME) and provides new insights for future research in tumor immunotherapy and precision medicine.


Assuntos
Adenosina Desaminase , Carcinoma Hepatocelular , Carcinoma de Células Renais , Regulação Neoplásica da Expressão Gênica , Neoplasias Renais , Neoplasias Hepáticas , Proteínas de Ligação a RNA , Microambiente Tumoral , Adenosina Desaminase/genética , Adenosina Desaminase/metabolismo , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/metabolismo , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/mortalidade , Neoplasias Renais/genética , Neoplasias Renais/patologia , Neoplasias Renais/metabolismo , Neoplasias Renais/mortalidade , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/patologia , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Prognóstico , Feminino , Masculino , Biomarcadores Tumorais/metabolismo , Biomarcadores Tumorais/genética , Pessoa de Meia-Idade
2.
World J Hepatol ; 16(4): 537-549, 2024 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-38689749

RESUMO

The tumor microenvironment is a complex network of cells, extracellular matrix, and signaling molecules that plays a critical role in tumor progression and metastasis. Lymphatic and blood vessels are major routes for solid tumor metastasis and essential parts of tumor drainage conduits. However, recent studies have shown that lymphatic endothelial cells (LECs) and blood endothelial cells (BECs) also play multifaceted roles in the tumor microenvironment beyond their structural functions, particularly in hepatocellular carcinoma (HCC). This comprehensive review summarizes the diverse roles played by LECs and BECs in HCC, including their involvement in angiogenesis, immune modulation, lymphangiogenesis, and metastasis. By providing a detailed account of the complex interplay between LECs, BECs, and tumor cells, this review aims to shed light on future research directions regarding the immune regulatory function of LECs and potential therapeutic targets for HCC.

3.
Sci Data ; 11(1): 344, 2024 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-38582756

RESUMO

The research of plant seeds has always been a focus of agricultural and forestry research, and seed identification is an indispensable part of it. With the continuous application of artificial intelligence technology in the field of agriculture, seed identification through computer vision can effectively promote the development of agricultural and forestry wisdom. Data is the foundation of computer vision, but there is a lack of suitable datasets in the agricultural field. In this paper, a seed dataset named LZUPSD is established. A device based on mobile phones and macro lenses was established to acquire images. The dataset contains 4496 images of 88 different seeds. This dataset can not only be used as data for training deep learning models in the computer field, but also provide important data support for agricultural and forestry research. As an important resource in this field, this dataset plays a positive role in modernizing agriculture and forestry.


Assuntos
Inteligência Artificial , Sementes , Agricultura , Agricultura Florestal
4.
Materials (Basel) ; 17(8)2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38673231

RESUMO

The preparation of electrocatalysts with high performance for the ethanol oxidation reaction is vital for the large-scale commercialization of direct ethanol fuel cells. Here, we successfully synthesized a high-performance electrocatalyst of a AuPd alloy with a decreased alloying degree via pulsed laser irradiation in liquids. As indicated by the experimental results, the photochemical effect-induced surficial deposition of Pd atoms, combined with the photothermal effect-induced interdiffusion of Au and Pd atoms, resulted in the formation of AuPd alloys with a decreased alloying degree. Structural characterization reveals that L-AuPd exhibits a lower degree of alloying compared to C-AuPd prepared via the conventional co-reduction method. This distinct structure endows L-AuPd with outstanding catalytic activity and stability in EOR, achieving mass and specific activities as high as 16.01 A mgPd-1 and 20.69 mA cm-2, 9.1 and 5.2 times than that of the commercial Pd/C respectively. Furthermore, L-AuPd retains 90.1% of its initial mass activity after 300 cycles. This work offers guidance for laser-assisted fabrication of efficient Pd-based catalysts in EOR.

6.
Am J Transl Res ; 16(2): 387-399, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38463579

RESUMO

Non-alcoholic fatty liver disease (NAFLD) is a complex disease characterized by a massive accumulation of lipids in the liver, with a continuous progression of simple steatosis, non-alcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular carcinoma. Non-alcoholic fatty liver disease is associated with obesity, insulin resistance, and metabolic syndrome; it is a severe public health risk and is currently the most common liver disease of the world. In addition to the fatty infiltration of the liver in non-alcoholic fatty liver disease patients, the field of liver transplantation faces similar obstacles. NAFLD and NASH primarily involve lipotoxicity, inflammation, oxidative stress, and insulin resistance. However, the precise mechanisms and treatments remain unclear. Therapeutic approaches encompass exercise, weight control, as well as treatments targeting antioxidants and anti-inflammatory pathways. The role of animal models in research has become crucial as a key tool to explore the molecular mechanisms and potential treatments for non-alcoholic fatty liver disease and non-alcoholic steatohepatitis. Here, we summarized the current understanding of the pathogenesis of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis and discussed animal models commonly used in recent years.

8.
Genes (Basel) ; 14(10)2023 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-37895310

RESUMO

Chemokines and their receptors play an important role in immune monitoring and immune defense during tumor growth and metastasis. However, their prognostic roles in pan-cancer have not been elucidated. In this work, we screened all chemokine receptors in pan-cancer and discovered X-C Motif Chemokine Receptor 1 (XCR1) as a reliable immunological and prognostic biomarker in pan-cancer using bioinformation. The TCGA database served as the foundation for the primary research database analysis in this work. XCR1 was downregulated in tumors. Patients with reduced XCR1 showed worse prognoses and a concomitant decrease in immune cell infiltration (DCs and CD8+ T cells). According to a gene enrichment study, XCR1 enhanced immune system performance by promoting T-cell infiltration through the C-X-C Motif Chemokine Ligand 9 (CXCL9)- C-X-C Motif Chemokine Receptor 3 (CXCR3) axis. In addition, XCR1 is mainly expressed in infiltrated DCs and some malignant cells in tumor tissues. Our data revealed the important role of XCR1 in remodeling the tumor microenvironment and predicting the survival prognosis, which could also be used as a sensitive biomarker for tumor immunotherapy.


Assuntos
Linfócitos T CD8-Positivos , Neoplasias , Humanos , Biomarcadores , Neoplasias/genética , Prognóstico , Receptores de Quimiocinas/genética , Microambiente Tumoral/genética
9.
Ecotoxicol Environ Saf ; 263: 115279, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37480692

RESUMO

The growing presence of yttrium (Y) in the environment raises concern regarding its safety and toxicity. However, limited toxicological data are available to determine cardiotoxicity of Y and its underlying mechanisms. In the present study, yttrium chloride (YCl3) intervention with different doses was performed in male Kunming mice for the toxicological evaluation of Y in the heart. After 28 days of intragastric administration, 500 mg/kg·bw YCl3 induces iron accumulation in cardiomyocytes, and triggers ferroptosis through the glutathione peroxidase 4 (GPX4)/glutathione (GSH)/system Xc- axis via the inhibition of Nrf2 signaling pathway. This process led to cardiac lipid peroxidation and inflammatory response. Further RNA sequencing transcriptome analysis found that many genes involved in ferroptosis and lipid metabolism-related pathways were enriched. The ferroptosis induced by YCl3 in cardiomyocytes ultimately caused cardiac injury and dysfunction in mice. Our findings assist in the elucidation of the potential subacute cardiotoxicity of Y3+ and its underlying mechanisms.


Assuntos
Ferroptose , Miócitos Cardíacos , Masculino , Camundongos , Animais , Peroxidação de Lipídeos , Cardiotoxicidade , Ítrio , Inflamação , Ferro
10.
J Nanobiotechnology ; 21(1): 182, 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37280622

RESUMO

Due to its complicated pathophysiology, propensity for metastasis, and poor prognosis, colon cancer is challenging to treat and must be managed with a combination of therapy. Using rolling circle transcription (RCT), this work created a nanosponge therapeutic medication system (AS1411@antimiR-21@Dox). Using the AS1411 aptamer, this approach accomplished targeted delivery to cancer cells. Furthermore, analysis of cell viability, cell apoptosis, cell cycle arrest, reactive oxygen species (ROS) content, and mitochondrial membrane potential (MMP) levels revealed that functional nucleic acid nanosponge drug (FND) can kill cancer cells. Moreover, transcriptomics uncovered a putative mechanism for the FND anti-tumor effect. These pathways, which included mitotic metaphase and anaphase as well as the SMAC-mediated dissociation of the IAP: caspase complexes, were principally linked to the cell cycle and cell death. In conclusion, by triggering cell cycle arrest and apoptosis, the nano-synergistic therapeutic system allowed for the intelligent and effective targeted administration of RNA and chemotherapeutic medicines for colon cancer treatment. The system allowed for payload efficiency while being customizable, targeted, reliable, stable, and affordable.


Assuntos
Aptâmeros de Nucleotídeos , Neoplasias do Colo , Nanopartículas , Ácidos Nucleicos , Humanos , Doxorrubicina/uso terapêutico , Sistemas de Liberação de Medicamentos , Ácidos Nucleicos/uso terapêutico , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/metabolismo , Portadores de Fármacos/uso terapêutico , Aptâmeros de Nucleotídeos/uso terapêutico , Oligodesoxirribonucleotídeos , Nanopartículas/uso terapêutico , Linhagem Celular Tumoral
11.
Small ; 19(25): e2207752, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36929582

RESUMO

Over the past decade, stem cell- and tumor-derived organoids are the most promising models in developmental biology and disease modeling, respectively. The matrix is one of three main elements in the construction of an organoid and the most important module of its extracellular microenvironment. However, the source of the currently available commercial matrix, Matrigel, limits the application of organoids in clinical medicine. It is worth investigating whether the original decellularized extracellular matrix (dECM) can be exploited as the matrix of organoids and improving organoid construction are very important. In this review, tissue decellularization protocols and the characteristics of decellularization methods, the mechanical support and biological cues of extraccellular matrix (ECM), methods for construction of multifunctional dECM and responsive dECM hydrogel, and the potential applications of functional dECM are summarized. In addition, some expectations are provided for dECM as the matrix of organoids in clinical applications.


Assuntos
Matriz Extracelular Descelularizada , Matriz Extracelular , Engenharia Tecidual/métodos , Organoides , Bioengenharia , Alicerces Teciduais
12.
Nutrients ; 15(6)2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36986171

RESUMO

Gestational diabetes mellitus (GDM) is a common disease of pregnancy, but with very limited knowledge of its impact on human milk oligosaccharides (HMOs) in breast milk. This study aimed to explore the lactational changes in the concentration of HMOs in exclusively breastfeeding GDM mothers and the differences between GDM and healthy mothers. A total of 22 mothers (11 GDM mothers vs. 11 healthy mothers) and their offspring were enrolled in the study and the levels of 14 HMOs were measured in colostrum, transitional milk, and mature milk. Most of the HMOs showed a significant temporal trend with decreasing levels over lactation; however, there were some exceptions for 2'-Fucosyllactose (2'-FL), 3-Fucosyllactose (3-FL), Lacto-N-fucopentaose II (LNFP-II), and Lacto-N-fucopentaose III (LNFP-III). Lacto-N-neotetraose (LNnT) was significantly higher in GDM mothers in all time points and its concentrations in colostrum and transitional milk were correlated positively with the infant's weight-for-age Z-score at six months postnatal in the GDM group. Significant group differences were also found in LNFP-II, 3'-Sialyllactose (3'-SL), and Disialyllacto-N-tetraose (DSLNT) but not in all lactational periods. The role of differently expressed HMOs in GDM needs to be further explored by follow-up studies.


Assuntos
Diabetes Gestacional , Leite Humano , Lactente , Feminino , Gravidez , Humanos , Lactação , Aleitamento Materno , Mães , Oligossacarídeos
13.
Nanoscale ; 15(4): 1554-1560, 2023 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-36519784

RESUMO

Improving the activity and stability of electrocatalysts for the hydrogen evolution reaction (HER) plays an essential role in the practical application of electrochemical water splitting under alkaline conditions. Here, trace Pd-doped Ru nanoparticles have been achieved using the pulsed laser ablation in liquid technology, which exhibit efficient HER catalytic performance. It is evidenced that the Pd doping amount is maintained at a trace level and increases nonlinearly with the concentration of the Pd precursor. Molecular dynamics simulations demonstrate that the trace doping of Pd is due to the slow thermal decomposition rate of the Pd precursor. This work improves the mechanistic explanation of the metal doping induced by liquid-phase laser ablation, which may promote the fabrication and application of advanced laser-based nanostructures.

14.
Small ; 19(4): e2205587, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36437112

RESUMO

Strain engineering of electrocatalysts provides an effective strategy to improve the intrinsic catalytic activity. Here, the defect-rich crystalline/amorphous Pd nanosheet aerogel with hybrid microstrain and lattice strain is synthesized by combining laser irradiation and phosphorus doping methods. The surface strain exhibited by the microstrain and lattice strain shifts the d-band center of the electrocatalyst, enhancing the adsorption of intermediates in the ethanol oxidation reaction and thus improving the catalytic performances. The measured mass activity, specific activity and C1-path selectivity of the Pd nanosheet aerogel are 4.48, 3.06, and 5.06 times higher than those of commercial Pd/C, respectively. These findings afford a new strategy for the preparation of highl activity and C1 pathway selective catalysts and provide insight into the catalytic mechanism of strain-rich heterojunction materials based on tunable surface strain values.

15.
Sci Total Environ ; 857(Pt 3): 159673, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36288751

RESUMO

The data incompleteness of aerosol optical depth (AOD) products and their lack of availability in highly urbanized areas limit their great potential of application in air quality research. In this study, we developed an ensemble machine-learning approach that integrated random forest-based Space Interpolation Model (SIM) and deep neural network-based Time Interpolation Model (TIM) to achieve high spatiotemporal resolution dataset of AOD. The spatial interpolation model first filled the spatial gaps in the Level-2 Himawari-8 hourly AOD product in 0.05° (∼5 km) spatial resolution, while the time interpolation model further improved the temporal resolution to 10 min on its basis. A full-coverage AOD dataset of Beijing-Tianjin-Hebei (BTH), Yangtze River Delta (YRD) and Pearl River Delta (PRD) in 2020 was obtained as a practical implementation. The validation against in-situ AOD observations from AERONET and SONET indicated that this new dataset was satisfactory (R = 0.80), and especially in spring and summer. Overall, our ensemble machine-learning model provided an effective scheme for reconstruction of AOD with high spatiotemporal resolution of 0.05° and 10 min, which may further advance the near-real-time monitoring of air-quality in urban areas.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Material Particulado/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Aerossóis/análise , Poluição do Ar/análise , Aprendizado de Máquina
16.
JPEN J Parenter Enteral Nutr ; 47(1): 151-158, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-35975334

RESUMO

BACKGROUND: The prevalence of malnutrition is unknown in patients with Hirschsprung disease. Undernutrition is associated with poor clinical outcomes. This study aims to describe the nutrition status among patients with Hirschsprung disease at admission. METHODS: We retrospectively used data from children with Hirschsprung disease admitted to three pediatric surgery centers in China from January 2016 to December 2020. The weight-for-age z scores (WAZ), height-for-age z scores (HAZ), and body mass index-for-age z scores (BAZ) were calculated as the reference for nutrition risk according to the World Health Organization child growth standards. The nutrition status of enrolled children was described and nutrition risk in each clinical characteristic was compared. The association between nutrition status and clinical outcomes was analyzed using univariate and multivariate logistic regression. RESULTS: A total of 624 patients were included in this study. The mean WAZ, HAZ, and BAZ of all patients was -0.64 ± 1.40, -0.45 ± 1.78, and -0.43 ± 1.50, respectively. Moderate to severe overall undernutrition was 16.3% (102/624). We found that WAZ and BAZ were significantly reduced with the length of aganglionic segments (P = 0.001). Children who had a definitive surgery at 3 years of age or older had significantly lower HAZ (P = 0.001). A multivariate regression model assessing postoperative Hirschsprung-associated enterocolitis showed that the WAZ was one of the independent risk factors (P = 0.001). CONCLUSION: Undernutrition is prevalent among children with Hirschsprung disease. Nutrition assessment to identify individuals at risk of undernutrition for further intervention is necessary.


Assuntos
Doença de Hirschsprung , Desnutrição , Humanos , Criança , Lactente , Estudos Transversais , Doença de Hirschsprung/complicações , Doença de Hirschsprung/cirurgia , Estudos Retrospectivos , Desnutrição/diagnóstico , Desnutrição/epidemiologia , Desnutrição/etiologia , Estado Nutricional
17.
J Infect Dev Ctries ; 16(8): 1302-1307, 2022 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-36099373

RESUMO

INTRODUCTION: Recurrent spontaneous abortion (RSA) is an important reproductive health issue with a serious adverse effect on patients and their families worldwide. The present study evaluated the association between mycoplasma infections and RSA in pregnant patients. METHODOLOGY: This case-control study included 107 patients with RSA (study group) and 89 normal pregnant women who had planned abortions (control group) between March 2019 and February 2021. Cervical swabs were assessed for the presence of Mycoplasma hominis and Ureaplasma urealyticum by Microtiter Plate Hybridization assay. RESULTS: A total of 52 (48.6%) patients from the study group and 13 (14.6%) patients from control group were positive for mycoplasmas. The presence of M. hominis (29.9% vs. 9%; p = 0.024), U. urealyticum (18.7% vs. 5.6%; p = 0.015) and the co-infection of M. hominis/U. urealyticum (14% vs. 1%; p = 0.032) were significantly higher in the study group. Multivariate analysis revealed that pelvic pain (Odds Ratio [OR] = 3.42; 95% CI = 0.40-3.65; p = 0.015), dysuria (OR = 4.12; 95% CI = 1.59-8.23; p = 0.021), and urinary tract infection (OR = 3.97; 95% CI = 1.52-4.17; p = 0.032) were independent predictors of RSA. CONCLUSIONS: The high prevalence of M. hominis/U. urealyticum in this study reveals a significant association with RSA. Pelvic pain and Mycoplasma infections are independent predictors of RSA.


Assuntos
Aborto Espontâneo , Infecções por Mycoplasma , Infecções por Ureaplasma , Aborto Espontâneo/epidemiologia , Estudos de Casos e Controles , Feminino , Humanos , Infecções por Mycoplasma/complicações , Infecções por Mycoplasma/epidemiologia , Dor Pélvica/complicações , Gravidez , Infecções por Ureaplasma/complicações , Infecções por Ureaplasma/epidemiologia
18.
Arab J Gastroenterol ; 23(3): 206-209, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35918288

RESUMO

BACKGROUND AND STUDY AIMS: The ability to predict severe acute pancreatitis (SAP) at an early stage is crucial for reducing the associated complications and mortality. In this study, we compared the ratio of red cell distribution width to albumin (RDW-to-ALB) using predictive scoring systems, such as the Ranson score, BISAP, and MCTSI, to develop a simple and accurate method of predicting SAP. PATIENTS AND METHODS: We included 212 patients with mild acute pancreatitis (MAP) and 89 with SAP between January 2013 and December 2018. The differences in the general characteristics and biochemical analysis as well as the various predictive scores were compared between the two groups. We evaluated the sensitivity and specificity between the RDW-to-ALB ratio, RDW, ALB, and multiple predictive scores in patients with early acute pancreatitis (AP) by using the receiver operating characteristic (ROC) curve. RESULTS: The RDW-to-ALB ratio (%) of patients with SAP was higher than that of patients with MAP (0.43 ± 0.08 vs. 0.32 ± 0.04, p < 0.001). Patients with SAP had higher Ranson, BISAP, and MCTSI scores than those with MAP. The ROC curve revealed that, when the RDW-to-ALB ratio (%) was >0.36, the sensitivity and specificity of the predicted SAP were 80.0% and 80.7%, respectively. Further statistical analysis found that the RDW-to-ALB ratio and Ranson, BISAP, and MCTSI scores were consistent in predicting SAP effectiveness (P > 0.05). CONCLUSIONS: The RDW-to-ALB ratio has a promising predictive power for SAP, and its effectiveness is comparable with those of Ranson, BISAP, and MCTSI scores.


Assuntos
Pancreatite , Doença Aguda , Índices de Eritrócitos , Humanos , Pancreatite/diagnóstico , Valor Preditivo dos Testes , Prognóstico , Curva ROC , Estudos Retrospectivos , Albumina Sérica , Índice de Gravidade de Doença
19.
Materials (Basel) ; 15(13)2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35806759

RESUMO

Reducing the loose-layer-to-dense-layer ratio in PEO coatings on aluminum and its alloys is the key to improving their corrosion resistance and expanding their applications in the aerospace industry and other fields. In this paper, we describe the discharge evolution during the PEO process in exhaustive detail and report the appearance of a novel "chain-like" discharge for the first time. We investigated the microstructure and composition of PEO coatings using a scanning electron microscope (SEM) equipped with an energy-dispersive spectrometer (EDS) and an X-ray diffractometer (XRD). The results reflected that the coating composition changed from amorphous Al2O3 to crystalline γ-Al2O3 and α-Al2O3 phases with the evolution of the plasma spark discharge state. We evaluated the electrochemical behavior of the coatings using a potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. Under "chain-like" discharge, the icorr of the coating on Al was 8.564 × 10-9 A∙cm-2, which was five orders of magnitude lower than that of the sample without the PEO coating. Moreover, we evaluated the adhesion strength of the coatings at different stages using a pull-off test. The adhesion strength of the PEO coatings at stage V reached 70 MPa. Furthermore, the high content of α-Al2O3 increased the hardness of the coating to 2000 HV. Therefore, the "chain-like" discharge promoted the formation of a single dense layer with 2.8% porosity and that demonstrated excellent properties. We also propose a mechanism to explain the influence of the plasma spark discharge state on the microstructure and composition of the PEO coatings.

20.
J Geophys Res Atmos ; 127(9): e2021JD035687, 2022 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-35865809

RESUMO

We conduct the first 4D-Var inversion of NH3 accounting for NH3 bi-directional flux, using CrIS satellite NH3 observations over Europe in 2016. We find posterior NH3 emissions peak more in springtime than prior emissions at continental to national scales, and annually they are generally smaller than the prior emissions over central Europe, but larger over most of the rest of Europe. Annual posterior anthropogenic NH3 emissions for 25 European Union members (EU25) are 25% higher than the prior emissions and very close (<2% difference) to other inventories. Our posterior annual anthropogenic emissions for EU25, the UK, the Netherlands, and Switzerland are generally 10%-20% smaller than when treating NH3 fluxes as uni-directional emissions, while the monthly regional difference can be up to 34% (Switzerland in July). Compared to monthly mean in-situ observations, our posterior NH3 emissions from both schemes generally improve the magnitude and seasonality of simulated surface NH3 and bulk NH x wet deposition throughout most of Europe, whereas evaluation against hourly measurements at a background site shows the bi-directional scheme better captures observed diurnal variability of surface NH3. This contrast highlights the need for accurately simulating diurnal variability of NH3 in assimilation of sun-synchronous observations and also the potential value of future geostationary satellite observations. Overall, our top-down ammonia emissions can help to examine the effectiveness of air pollution control policies to facilitate future air pollution management, as well as helping us understand the uncertainty in top-down NH3 emissions estimates associated with treatment of NH3 surface exchange.

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