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Science Advances Nov 2022Chronic exposure to airborne carbon black ultrafine (nCB) particles generated from incomplete combustion of organic matter drives IL-17A-dependent emphysema. However,...
Chronic exposure to airborne carbon black ultrafine (nCB) particles generated from incomplete combustion of organic matter drives IL-17A-dependent emphysema. However, whether and how they alter the immune responses to lung cancer remains unknown. Here, we show that exposure to nCB particles increased PD-L1 PD-L2 CD206 antigen-presenting cells (APCs), exhausted T cells, and T cells. Lung macrophages that harbored nCB particles showed selective mitochondrial structure damage and decreased oxidative respiration. Lung macrophages sustained the HIF1α axis that increased glycolysis and lactate production, culminating in an immunosuppressive microenvironment in multiple mouse models of non-small cell lung cancers. Adoptive transfer of lung APCs from nCB-exposed wild type to susceptible mice increased tumor incidence and caused early metastasis. Our findings show that nCB exposure metabolically rewires lung macrophages to promote immunosuppression and accelerates the development of lung cancer.
Topics: Mice; Animals; Soot; Particulate Matter; Lung Neoplasms; Macrophages; Lung; Carbon; Tumor Microenvironment
PubMed: 36383649
DOI: 10.1126/sciadv.abq0615 -
The European Respiratory Journal Jul 2023https://bit.ly/43d9A75
https://bit.ly/43d9A75
Topics: Humans; COVID-19; Soot; Air Pollution; SARS-CoV-2
PubMed: 37343979
DOI: 10.1183/13993003.00818-2023 -
Molecules (Basel, Switzerland) Sep 2023Soot formation is an inevitable consequence of the combustion of carbonaceous fuels in environments rich in reducing agents. Efficient management of pollution in various... (Review)
Review
Soot formation is an inevitable consequence of the combustion of carbonaceous fuels in environments rich in reducing agents. Efficient management of pollution in various contexts, such as industrial fires, vehicle engines, and similar applications, relies heavily on the subsequent oxidation of soot particles. Among the oxidizing agents employed for this purpose, oxygen, carbon dioxide, water vapor, and nitrogen dioxide have all demonstrated effectiveness. The scientific framework of this research can be elucidated through the following key aspects: (i) This review situates itself within the broader context of pollution management, emphasizing the importance of effective soot oxidation in reducing emissions and mitigating environmental impacts. (ii) The central research question of this study pertains to the identification and evaluation of catalysts for soot oxidation, with a specific emphasis on ceria-based catalysts. The formulation of this research question arises from the need to enhance our understanding of catalytic mechanisms and their application in environmental remediation. This question serves as the guiding principle that directs the research methodology. (iii) This review seeks to investigate the catalytic mechanisms involved in soot oxidation. (iv) This review highlights the efficacy of ceria-based catalysts as well as other types of catalysts in soot oxidation and elucidate the underlying mechanistic strategies. The significance of these findings is discussed in the context of pollution management and environmental sustainability. This study contributes to the advancement of knowledge in the field of catalysis and provides valuable insights for the development of effective strategies to combat air pollution, ultimately promoting a cleaner and healthier environment.
PubMed: 37836727
DOI: 10.3390/molecules28196884 -
International Journal of Molecular... Oct 2022RSV is one of the major infectious agents in paediatrics, and its relationship with air pollution is frequently observed. However, the molecular basis of this... (Review)
Review
RSV is one of the major infectious agents in paediatrics, and its relationship with air pollution is frequently observed. However, the molecular basis of this interaction is sparsely reported. We sought to systematically review the existing body of literature and identify the knowledge gaps to answer the question: which molecular mechanisms are implied in the air pollutants-RSV interaction? Online databases were searched for original studies published before August 2022 focusing on molecular mechanisms of the interaction. The studies were charted and a narrative synthesis was based upon three expected directions of influence: a facilitated viral entry, an altered viral replication, and an inappropriate host reaction. We identified 25 studies published between 1993 and 2020 (without a noticeable increase in the number of studies) that were performed in human (n = 12), animal (n = 10) or mixed (n = 3) models, and analysed mainly cigarette smoke (n = 11), particulate matter (n = 4), nanoparticles (n = 3), and carbon black (n = 2). The data on a damage to the epithelial barrier supports the hypothesis of facilitated viral entry; one study also reported accelerated viral entry upon an RSV conjugation to particulate matter. Air pollution may result in the predominance of necrosis over apoptosis, and, as an effect, an increased viral load was reported. Similarly, air pollution mitigates epithelium function with decreased IFN-γ and Clara cell secretory protein levels and decreased immune response. Immune response might also be diminished due to a decreased viral uptake by alveolar macrophages and a suppressed function of dendritic cells. On the other hand, an exuberant inflammatory response might be triggered by air pollution and provoke airway hyperresponsiveness (AHR), prolonged lung infiltration, and tissue remodeling, including a formation of emphysema. AHR is mediated mostly by increased IFN-γ and RANTES concentrations, while the risk of emphysema was related to the activation of the IL-17 → MCP-1 → MMP-9 → MMP-12 axis. There is a significant lack of evidence on the molecular basics of the RSV-air pollution interaction, which may present a serious problem with regards to future actions against air pollution effects. The major knowledge gaps concern air pollutants (mostly the influence of cigarette smoke was investigated), the mechanisms facilitating an acute infection or a worse disease course (since it might help plan short-term, especially non-pharmacological, interventions), and the mechanisms of an inadequate response to the infection (which may lead to a prolonged course of an acute infection and long-term sequelae). Thus far, the evidence is insufficient regarding the broadness and complexity of the interaction, and future studies should focus on common mechanisms stimulated by various air pollutants and a comparison of influence of the different contaminants at various concentrations.
Topics: Animals; Humans; Child; Interleukin-17; Matrix Metalloproteinase 9; Matrix Metalloproteinase 12; Soot; Uteroglobin; Air Pollution; Air Pollutants; Particulate Matter; Pulmonary Emphysema; Emphysema; Respiratory Syncytial Virus Infections
PubMed: 36293561
DOI: 10.3390/ijms232012704 -
ACS Omega Apr 2022Aircraft soot has a significant effect on the air quality and human health. The aim of this study is to investigate the evolution of soot morphology in free jet laminar...
Aircraft soot has a significant effect on the air quality and human health. The aim of this study is to investigate the evolution of soot morphology in free jet laminar diffusion flames between Chinese traditional aviation kerosene RP-3 and algae-based aviation biofuels. The differences in height, profile, and structural properties of soot between the RP-3 flame and biofuel flame are determined. A laboratory-made probe sampling method was applied for soot sample collection. Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and elemental analyzers were used to analyze the collected soot particles. The average particle size of soot increases first and then decreases in both flames, and the size of biofuel primary particles is smaller than that of jet fuel RP-3 particles along the same flame height. At the flame tip, the primary particle sizes of RP-3 soot and biofuel soot are 22.7 and 15.6 mm, respectively. In comparison with the RP-3 soot, the nanostructure of biofuel soot particles along the same flame height exhibits a shorter fringe lattice, a larger fringe tortuosity, and a larger interlayer spacing, which indicate a higher degree of oxidation reactivity. Meanwhile, RP-3 soot particles have a lower H/C atom ratio and have greater intensity in X-ray diffraction, which indicates a more orderly and compact lattice structure. This study provides some references in studying the algae-based biofuel with regard to soot formation.
PubMed: 35449979
DOI: 10.1021/acsomega.1c05125 -
Journal of Microscopy Oct 2022A pre-trained convolution neural network based on residual error functions (ResNet) was applied to the classification of soot and non-soot carbon nanoparticles in TEM...
A pre-trained convolution neural network based on residual error functions (ResNet) was applied to the classification of soot and non-soot carbon nanoparticles in TEM images. Two depths of ResNet, one 18 layers deep and the other 50 layers deep, were trained using training-validation sets of increasing size (containing 100, 400 and 1400 images) and were assessed using an independent test set of 200 images. Network training was optimised in terms of mini-batch size, learning rate and training length. In all tests, ResNet18 and ResNet50 had statistically similar performances, though ResNet18 required only 25-35% of the training time of ResNet50. Training using the 100-, 400- and 1400-image training-validation sets led to classification accuracies of 84%, 88% and 95%, respectively. ResNet18 and ResNet50 were also compared for their ability to categorise soot and non-soot nanoparticles via a fivefold cross-validation experiment using the entire set of 800 images of soot and 800 images of non-soot. Cross-validation was repeated 3 times with different training durations. For all cross-validation experiments, classification accuracy exceeded 91%, with no statistical differences between any of the network trainings. The most efficient network was ResNet18 trained for 5 epochs, which reached 91.2% classification after only 84 s of training on 1600 images. Use of ResNet for classification of 1000 images, the amount suggested for reliable characterisation of soot sample, requires <4 s, compared with >30 min for a skilled operator classifying images manually. Use of convolution neural networks for classification of soot and non-soot nanoparticles in TEM images is highly promising, particularly when manually classified data sets have already been established.
Topics: Carbon; Nanoparticles; Neural Networks, Computer; Soot
PubMed: 36065981
DOI: 10.1111/jmi.13140 -
Frontiers in Public Health 2022Various synthetic powders with primary particle sizes at the nanoscale and a high commercial impact have been studied using Wistar rats. The test materials were metal... (Review)
Review
Various synthetic powders with primary particle sizes at the nanoscale and a high commercial impact have been studied using Wistar rats. The test materials were metal oxides, i.e., TiO, ZnO and amorphous silica, and carbon black (technical soot). Dosing schemes were in the regular ranges typically used in subacute rat studies to simulate occupational exposure scenarios (mg range). Nanoscaled particle agglomerates have the potential to disintegrate and translocate as individual nanoparticles to remote locations following deposition in the lungs. The toxicokinetic fate of metal oxides post-inhalation in lungs/organs was investigated (i) by chemical analysis of the retained particulate/dissolved matter and (ii) by visualization of particles in various remote organs using transmission electron microscopy (TEM). The three titanium dioxides (NM-103, NM-104, NM-105; JRC coding) showed a very slow dissolution in lung fluids. In contrast, the coated ZnO (NM-111) dissolved quickly and was eliminated from the body within approximately 1 day. The precipitated amorphous silica (NM-200) showed a partial dissolution. Chemical analysis in lungs (particulate and soluble TiO) and in remote organs (liver and brain) showed a small solubility effect under physiological conditions. The translocation to remote organs was negligible. This confirms that for poorly soluble TiO particles there was no considerable translocation to the liver and brain. The chemical analysis of zinc demonstrated a very rapid dissolution of ZnO particles after deposition in the lungs. Statistically significant increases in Zn levels in the lungs were detectable only on day 1 post-exposure (NM-111). Overall, no relevant amounts of increased NM-111 in the ionic or particulate matter were detected in any body compartment. Amorphous silica (NM-200) particles were found in the cytoplasm of intraalveolar macrophages in the lung and the cytoplasm of macrophages in the lung associated lymph node. Interestingly, these particles were found in a few animals of all treatment groups (1, 2.5, and 5 mg/m NM-200) even after 91 days post-exposure. In all other organs of the NM-200 treated animals such as the nasal epithelium, trachea, larynx, liver, spleen, kidney, and mesenteric lymph node no particles were found at any time point investigated. Carbon black was tagged internally ("intrinsically") with a γ tracer (beryllium; half-time: 53.3 days). Due to limited amounts, the test item (0.3 mg per rat lung) was intratracheally instilled into the lungs. This dose avoided a particle overload effect, meaning that the toxicokinetic fate of carbon black could be followed under the approximated physiological conditions of lung clearance. Analysis of the γ labeled carbon black confirmed conclusively that there was no evidence for the translocation of carbon black beyond the lung into the blood or other body compartments. Very small amounts were only detected in lung-associated lymph nodes (LALN). On day 20 post-treatment, upon necropsy, both carbon black samples were practically exclusively found in lungs (75.1% and 91.0%, respectively) and in very small amounts in the lung-associated lymph nodes (LALN), i.e., ~0.5%. In the other organs/tissues, the test item was not significantly detectable. Separation of leukocytes and cell-free supernatant of a bronchoalveolar lavagate by centrifugation revealed that carbon black was completely located in the cell sediment, indicating total engulfment by alveolar macrophages. In conclusion, in occupational settings the nanomaterials titanium dioxide, zinc oxide, amorphous silica, and carbon black acted as microscaled agglomerates, not as individual nanoparticles. They displayed no potential to translocate beyond the lung into the blood compartment. Besides lungs, very small particulate amounts were detected only in LALN. This finding is consistent with the behavior of microscaled poorly soluble particles. Overall, there was no evidence of translocation of the nanomaterials following pulmonary exposures.
Topics: Animals; Lung; Nanoparticles; Occupational Exposure; Oxides; Particulate Matter; Rats; Rats, Wistar; Silicon Dioxide; Soot; Toxicokinetics; Zinc Oxide
PubMed: 35801236
DOI: 10.3389/fpubh.2022.909247 -
Scientific Reports Feb 2024Biomass combustion provides energy needs for millions of people worldwide. However, soot accumulation on the combustors' walls significantly reduces heat transfer...
Biomass combustion provides energy needs for millions of people worldwide. However, soot accumulation on the combustors' walls significantly reduces heat transfer efficiency. Herein, we demonstrate how microtextured surfaces minimize soot accumulation by enhancing soot oxidation. We investigate soot layers from the combustion of paraffin wax as a model for wood-based soot, and find that randomly microtextured glass obtained by sandblasting shows a 71% reduction in the time taken to oxidize 90% of surface soot coverage when compared to smooth glass at 530 °C. We also study grooved microtextures fabricated via laser ablation and find that grooves with widths between 15 and 50 µm enhance soot oxidation, while the expedited advantage is lost when the groove width is 85 µm. X-ray photoelectron spectroscopy validates the superior extent of soot removal on microtextures down to a sub-nanometer length-scale. The high density of sharp features such as peaks and edges on microtextures, and the conformality of the soot layer to the microtextures contribute to increased soot oxidation. We also demonstrate enhanced soot oxidation on microtextured stainless steel, the principal material of construction in biomass combustors. Microtextured surfaces that facilitate soot oxidation upon contact could significantly improve performance and longevity in various combustion applications.
PubMed: 38378782
DOI: 10.1038/s41598-024-54320-5 -
Frontiers in Immunology 2017The environmental soot and carbon blacks (CBs) cause many diseases in humans, but their underlying mechanisms of toxicity are still poorly understood. Both are formed... (Review)
Review
The environmental soot and carbon blacks (CBs) cause many diseases in humans, but their underlying mechanisms of toxicity are still poorly understood. Both are formed after the incomplete combustion of hydrocarbons but differ in their constituents and percent carbon contents. For the first time, "Sir Percival Pott" described soot as a carcinogen, which was subsequently confirmed by many others. The existing data suggest three main types of diseases due to soot and CB exposures: cancer, respiratory diseases, and cardiovascular dysfunctions. Experimental models revealed the involvement of oxidative stress, DNA methylation, formation of DNA adducts, and Aryl hydrocarbon receptor activation as the key mechanisms of soot- and CB-induced cancers. Metals including Si, Fe, Mn, Ti, and Co in soot also contribute in the reactive oxygen species (ROS)-mediated DNA damage. Mechanistically, ROS-induced DNA damage is further enhanced by eosinophils and neutrophils halide (Cl and Br) dependent DNA adducts formation. The activation of pulmonary dendritic cells, T helper type 2 cells, and mast cells is crucial mediators in the pathology of soot- or CB-induced respiratory disease. Polyunsaturated fatty acids (PUFAs) were also found to modulate T cells functions in respiratory diseases. Particularly, telomerase reverse transcriptase was found to play the critical role in soot- and CB-induced cardiovascular dysfunctions. In this review, we propose integrated mechanisms of soot- and CB-induced toxicity emphasizing the role of inflammatory mediators and oxidative stress. We also suggest use of antioxidants and PUFAs as protective strategies against soot- and CB-induced disorders.
PubMed: 28713383
DOI: 10.3389/fimmu.2017.00763 -
ACS Omega Dec 2020The bright spot phenomenon during the gas explosion was because of the soot particles of high heat radiation characteristics generated during the explosion process. The...
The bright spot phenomenon during the gas explosion was because of the soot particles of high heat radiation characteristics generated during the explosion process. The formation mechanism of soot and precursor polycyclic aromatic hydrocarbons (PAHs) of the methane explosion was numerically simulated using CHEMKIN-PRO. The methane explosion soot of the CH-air premixed gas explosion experiments with volume concentrations of 8% was collected, and the pore size distribution and surface structure of the soot were analyzed by low-pressure nitrogen gas adsorption (LP-NGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that C2 and C3 play an important role in the formation of PAHs in the early stage of the explosion reaction. The LP-NGA isotherms demonstrate that the pore type of the soot particles is mostly wedge-shaped, which was verified with SEM observations. The SEM analysis showed that the methane explosion soot is composed of a large number of spherical soot aggregates with diameters between 4 and 50 μm and the pores at the particle surface are well developed, some of the particles exhibit a melt sintering feature. Soot aggregates collide with each other with a chain-branched structure, and the diameters of the majority of the particles are of 100 nm according to TEM images. In addition, graphite-like lattice stripes can be clearly seen inside the particles when magnified to 8 nm. This work will provide the basis for further analysis of soot formation in the gas explosion process.
PubMed: 33344824
DOI: 10.1021/acsomega.0c04234