Aromatic Hydrocarbons Research Articles

Photoelectron spectroscopy of deprotonated benzonitrile.

The recent discovery of cyano-substituted aromatic and two-ring polycyclic aromatic hydrocarbon molecules in Taurus Molecular Cloud-1 has prompted questions on how the electronic structure and excited-state dynamics of these molecules are linked with their existence and abundance. Here, we report a photodetachment and frequency- and angle-resolved photoelectron spectroscopy study of jet-cooled para-deprotonated benzonitrile (p-[Bzn-H]-). The adiabatic detachment energy was determined as 1.70 ± 0.01eV, in good agreement with CCSD(T)/aug-cc-pVTZ calculations. The spectra across the first few electron-volts above threshold are dominated by prompt autodetachment processes associated with excitation of at least five short-lived (tens of femtoseconds) temporary anion shaped resonances since excitation cross sections are several orders of magnitude larger than direct photodetachment cross sections. The photoexcitation vibronic profile is dominated by a ≈640 cm-1 ring deformation mode. [Bzn-H]- lacks a valence-localized excited state situated below the detachment threshold and does not exhibit thermionic emission following excitation of the temporary anion resonances. Thus, [Bzn-H]- is unlikely to be stable in many interstellar environments.

Occurrence, characteristics, and risk assessment of microplastics and polycyclic aromatic hydrocarbons associated with microplastics in surface water and sediments of the Konya Closed Basin, Turkey

Occurrence, characteristics, and risk assessment of microplastics and polycyclic aromatic hydrocarbons associated with microplastics in surface water and sediments of the Konya Closed Basin, Turkey

Abstract C049: Aryl hydrocarbon receptor activity promotes cancer progression and drug resistance in castration-resistant prostate cancer cells

Abstract C049: Aryl hydrocarbon receptor activity promotes cancer progression and drug resistance in castration-resistant prostate cancer cells

The Galaxy Activity, Torus, and Outflow Survey (GATOS) V. Unveiling PAH survival and resilience in the circumnuclear regions of AGNs with JWST

This study analyses JWST MIRI/MRS observations of the infrared (IR) polycyclic aromatic hydrocarbon (PAH) bands in the nuclear (sim 0.4 at 11\,mu m; sim 75\,pc) and circumnuclear regions (inner sim kpc) of local active galactic nuclei (AGNs) from the Galactic Activity, Torus, and Outflow Survey (GATOS). We examine the PAH properties in the circumnuclear regions of AGNs and the projected direction of AGN-outflows and compare them to those in star-forming regions and the innermost regions of AGNs. This study employs 4.9-28.1\,mu m sub-arcsecond angular resolution data to investigate the properties of PAHs in three nearby sources L $ sim 30-40\,Mpc). Our findings are aligned with previous JWST studies, demonstrating that the central regions of AGNs display a larger fraction of neutral PAH molecules (i.e. elevated 11.3/6.2 and 11.3/7.7\,mu m PAH ratios) in comparison to star-forming galaxies. We find that AGNs might affect not only the PAH population in the innermost region, but also in the extended regions up to sim kpc scales. By comparing our observations to PAH diagnostic diagrams, we find that, in general, regions located in the projected direction of the AGN-outflow occupy similar positions on the PAH diagnostic diagrams as those of the innermost regions of AGNs. Star-forming regions that are not affected by the AGNs in these galaxies share the same part of the diagram as star-forming galaxies. We also examined the potential of the PAH-H$_2$ diagram to disentangle AGN-versus-star-forming activity. Our results suggest that in Seyfert-like AGNs, the illumination and feedback from the AGN might affect the PAH population at nuclear and kpc scales, particularly with respect to the ionisation state of the PAH grains. However, PAH molecular sizes are rather similar. The carriers of the ionised PAH bands (6.2 and 7.7\,mu m) are less resilient than those of neutral PAH bands (11.3\,mu m), which might be particularly important for strongly AGN-host coupled systems. Therefore, caution must be applied when using PAH bands as star-formation rate indicators in these systems even at kpc scales, with the effects of the AGN being more important for ionised ones.

Aryl hydrocarbon receptor dynamics in esophageal squamous cell carcinoma: From immune modulation to therapeutic opportunities

Esophageal squamous cell carcinoma (ESCC) is a substantial global health burden. Immune escape mechanisms are important in ESCC progression, enabling cancer cells to escape the surveillance of the host immune system. One key player in this process is the Aryl Hydrocarbon Receptor (AhR), which influences multiple cellular processes, including proliferation, differentiation, metabolism, and immune regulation. Dysregulated AhR signaling participates in ESCC development by stimulating carcinogenesis, epithelial-mesenchymal transition, and immune escape. Targeting AhR signaling is a potential therapeutic approach for ESCC, with AhR ligands showing efficacy in preclinical studies. Additionally, modification of AhR ligands and combination therapies present new opportunities for therapeutic intervention. This review aims to address the knowledge gap related to the role of AhR signaling in ESCC pathogenesis and immune escape.

Ecological and Geochemical Assessment of the State of Soils in the City of Baikalsk According to the Content of Polycyclic Aromatic Hydrocarbons

The pollution of the topsoils of the city of Baikalsk (Irkutsk region) under the influence of industrial emissions and wastes of the Baikal Pulp and Paper Mill (BPPM) was studied. The content of 16 individual PAH structures in samples of urban and background soils taken during the soil geochemical survey in the summer of 2019 was analyzed. Relatively low levels of PAH content were found in the lignin sludge from the BPPM and СHP ash. The concentration of total PAHs in CHP ash reaches 46 mg/ kg with a predominance of low molecular weight compounds (the proportion of naphthalene and its homologues is 24% and 34% of the total PAHs, respectively), among high molecular weight PAHs, 5-nuclear benzo(b)fluoranthene dominates (16%). In lignin sludge, the amount of PAHs is 7.16 mg/kg with the predominance of benzo(b)fluoranthene (83%). In the soils of Baikalsk, the average total content of PAHs (38.4 mg/kg) is 5 times higher than the background content. In urban soils, 4–5-nuclear fluoranthene (61.1%) and benzo(b)fluoranthene (29.4%) prevail. This makes it possible to attribute soil pollution to the fluoranthene type. The soils of the motor transport (total PAH 105 mg/kg) and industrial (59.5 mg/ kg) zones are the most polluted, where the most contrasting PAH anomalies were formed. In descending order of the amount of PAHs, the land use zones of the city form a series: motor transport industrial residential one-storey railway transport residential multi-storey recreational zone. Several local anomalies in the amount of PAHs are distinguished, forming two large pollution halos in the western and eastern parts of the city. The leading factors in the accumulation of high molecular weight PAHs in soils are acid-alkaline conditions and soil organic matter, while the accumulation of low molecular weight polyarenes is mainly controlled by pH. The environmental hazard of pollution of Baikalsk soils with polyarenes is due to benzo(b)fluoranthene, its contribution is 83.5%.

Transcriptome responses to benzo[a]pyrene in liver slices of sub-arctic fish species

Due to the expanding oil-related activities, the arctic and sub-arctic marine environments are increasingly vulnerable to oil-related pollution such as accidental oil spills. These cold-water ecosystems harbor many fish species that are both ecologically and economically important such as the pelagic polar cod (Boreogadus saida), capelin (Mallotus villosus), and benthic long rough dab (Hippoglossoides platessoides). The latter two are much less studied and it is crucial to characterize their responses to oil-related contaminants and develop molecular biomarkers and genomic resources for future monitoring. In this study, liver slice preparation and culture methods were used to characterize the transcriptome responses (using RNA-seq) in capelin and long rough dab to exposures of the polycyclic aromatic hydrocarbon (PAH) compound benzo[a]pyrene (BaP). The liver slice culture and exposure experiments were performed onboard a research vessel in the Barents Sea. Strong up-regulation of genes involved in biotransformation, particularly the aryl hydrocarbon receptor signaling pathway was observed in both species. A comparison of the number of differentially expressed genes (DEGs) with previously published polar cod exposures indicates that the latter responded more strongly (higher number of genes), suggesting higher uptake and bioconcentration of BaP in the fatty liver tissue, although other factors such as differences in clearance rate could potentially affect the responses. This study provides new genomic resources and gene expression biomarkers in capelin and long rough dab, enhancing our understanding of their response mechanism to oil-related contaminants.

Oxidative derivatives of polycyclic aromatic hydrocarbons in urine of smokers during transition to e-cigarettes

Oxidative derivatives of polycyclic aromatic hydrocarbons in urine of smokers during transition to e-cigarettes

Chronic and Periodic Effects of Smoke from Crop Residue Combustion on Soil Enzymatic Activity

Wildfires lead to the emission of large volumes of toxic smoke, which is transported hundreds of kilometres away from the fires and can have a negative impact on soil, biota and humans. A series of modelling experiments on pyrogenic fumigation of soil were carried out to assess the effects of gaseous products from wildfires on soil biochemical parameters. The effects of chronic exposure to gaseous substances and periodic, repetitive effects of smoke exposure on soil were determined. The results were compared with a single intensive smoke exposure. It was found that pyrogenic impact significantly affected the change of enzymatic activity of ordinary chernozem. The degree of influence depended on the duration and periodicity of smoke exposure. In all experiments enzymes of oxidoreductase class (catalase, peroxidase, polyphenol oxidase) were more sensitive to fumigation than invertase from hydrolase class. The reason of suppression of enzymatic activity of soils is high concentrations of toxic gases. The following concentrations exceeded the maximum permissible concentrations for atmospheric air: CO 714 times, phenol (hydroxybenzene) 441 times, acetaldehyde 24100 times, formaldehyde 190 times. Accumulation of polycyclic aromatic hydrocarbons (PAHs) in soil after fumigation was revealed, the total content of PAHs was 377 ng/g. The highest values were recorded for naphthalene, where the concentration was 4.4 times higher than the maximum permissible and phenanthrene 2.8 times higher than the maximum permissible. It was found that 60-minute intensive smoke affects the soil to a lesser extent than chronic and periodic. Indicators of enzymatic activity of chernozem after such fumigation decreased by 15-33% depending on the enzyme, in chronic and periodic by 41-84 and 31-78%, respectively. The obtained data indicate a significant effect of smoke on enzymatic activity of soils under chronic and periodic exposure to gaseous products of combustion.

Enhanced Removal of Refractory Organic Compounds from Coking Wastewater Using Polyaluminum Chloride with Coagulant Aids

This study explores the enhanced removal of refractory organic compounds from coking wastewater using polyaluminum chloride (PACl) with two different basicity levels (0.5 and 2.5), in combination with coagulant aids such as cationic polyacrylamide (CPAM) and iron ions. The results demonstrated that both PACl formulations significantly outperformed commercial PACl in terms of COD and color removal, with PACl at the basicity of 2.5 achieving slightly higher efficiency than PACl at the basicity of 0.5. The improved performance was attributed to the higher content of polymeric aluminum species, enhancing charge neutralization and bridging adsorption. The addition of coagulant aids further improved the performance, with PACl at the basicity of 2.5 combined with iron ions achieving the highest COD (48.41%) and color removal (80.77%), due to sweep coagulation and complexation. Organic composition analysis using gas chromatography–mass spectrometry (GC-MS), three-dimensional excitation–emission matrix (3D-EEM) fluorescence spectroscopy, and ultraviolet (UV) spectroscopy indicated that PACl combined with iron ions was the most effective in removing polycyclic aromatic hydrocarbons (PAHs) and nitrogen-, oxygen-, and sulfur-containing heterocyclic compounds. Additionally, a floc analysis showed that the flocs formed with iron ions were more compact and had better settleability compared to those formed with CPAM, further contributing to the improved coagulation efficiency. These results highlight the importance of optimizing the PACl basicity and coagulant aid selection for the enhanced removal of refractory organic compounds from coking wastewater, offering a promising strategy for advanced wastewater treatment.

Effect and interaction of PINK1 genetic polymorphisms and environmental factors on blood pressure in COEs-exposed workers

ABSTRACT Coke oven emissions (COEs) contain a variety of polycyclic aromatic hydrocarbons (PAHs), which can cause damage to the human cardiovascular system. In addition, myocardial mitochondria are susceptible to damage in hypertensive patients. However, it is not clear whether genetic variation, in single nucleotide polymorphisms (SNPs) in PINK1 affects COEs exposure-induced abnormal blood pressure. We surveyed and tested 518 workers exposed to COEs and statistically analyzed them with SPSS 21.0 software. SBP was greater in the high-exposure group than in the low-exposure group. Generalized linear model analysis showed that the interaction of PINK1 rs3738136 (GA+AA) and COEs had an effect on SBP [β(95%CI) = -6.537(−12.072, −1.002), p = 0.021] and DBP [β(95%CI) = -4.811(−8.567, −1.056), p = 0.012]. This study is the first to identify the role of PINK1 rs3738136 in COE- induced abnormal blood pressure, and to prove that the abnormal blood pressure of workers is the result of environmental and genetic factors.

Assessment of the In Vitro Phosphatidylinositol Glycan Class A (PIG-A) Gene Mutation Assay Using Human TK6 and Mouse Hepa1c1c7 Cell Lines

Gene mutations linked to diseases like cancer may be caused by exposure to environmental chemicals. The X-linked phosphatidylinositol glycan class A (PIG-A) gene, required for glycosylphosphatidylinositol (GPI) anchor biosynthesis, is a key target locus for in vitro genetic toxicity assays. Various organisms and cell lines may respond differently to genotoxic agents. Here, we compared the mutagenic potential of directly genotoxic ethyl methane sulfonate (EMS) to metabolically activated pro-mutagenic polycyclic aromatic hydrocarbons (PAHs). The two classes of mutagens were compared in an in vitro PIG-A gene mutation test using the metabolically active murine hepatoma Hepa1c1c7 cell line and the human TK6 cell line, which has limited metabolic capability. Determination of cell viability is required for quantifying mutagenicity. Two common cell viability tests, the MTT assay and propidium iodide (PI) staining measured by flow cytometry, were evaluated. The MTT assay overestimated cell viability in adherent cells at high benzo[a]pyrene (B[a]P) exposure concentrations, so PI-based cytotoxicity was used in calculations. The spontaneous mutation rates for TK6 and Hepa1c1c7 cells were 1.87 and 1.57 per million cells per cell cycle, respectively. TK6 cells exposed to 600 µM and 800 µM EMS showed significantly higher mutation frequencies (36 and 47 per million cells per cell cycle, respectively). Exposure to the pro-mutagen benzo[a]pyrene (B[a]P, 10 µM) did not increase mutation frequency in TK6 cells. In Hepa1c1c7 cells, mutation frequencies varied across exposure groups (50, 50, 29, and 81 per million cells per cell cycle when exposed to 10 µM B[a]P, 5-methylcholanthrene (5-MC), chrysene, or 16,000 µM EMS, respectively). We demonstrate that the choice of cytotoxicity assay and cell line can determine the outcome of the Pig-A mutagenesis assay when assessing a specific mutagen.

The aryl hydrocarbon receptor in environmentally induced cervical cancer: A Narrative review

The aryl hydrocarbon receptor (AhR) plays a crucial role in cellular responses to various environmental pollutants, including several known carcinogens. As a ligand-activated transcription factor, AhR activation modulates the expression of genes involved in critical cellular processes, including detoxification pathways, cell proliferation and differentiation, and immune system regulation. The AhR exhibits pleiotropic effects under normal physiological conditions, contributing to the development and function of various organ systems. AhR activity is important in angiogenesis, cardiomyocyte differentiation, oocyte maturation, oculomotor nerve formation, and hematopoietic stem cell maintenance. Additionally, AhR plays a role in regulating immune cell differentiation and function, maintaining the integrity of the intestinal epithelium and its associated immune system, and mediating UVB-induced DNA damage repair responses in the skin. It acts as a critical environmental sensor, mediating cellular responses to various exogenous ligands. Importantly, activation or inhibition of AhR affects distinct signaling pathways depending on the specific ligand and cellular context. Ligands for the AhR are divided into exogenous or endogenous and have agonistic or antagonistic activity. Recently, the AhR role was determined in cancer development. It can exert both tumor-promoting and tumor-suppressive effects depending on factors such as the specific ligand, cell type, and tissue microenvironment. Emerging evidence suggests that AhR may represent a promising target for immunotherapy and serve as a potential biomarker for cervical cancer. AhR interacts with apoptotic pathway, immune checkpoint system, steroid hormones, and immune cell regulation process in cervical cancer. Despite its potential significance, the precise role of AhR in cervical cancer development and progression is still unknown. In this review, we describe significant roles of AhR in gynecological cancers; e.g., in cervical cancer.

Bacteroides uniformis degrades β-glucan to promote Lactobacillus johnsonii improving indole-3-lactic acid levels in alleviating colitis

BackgroundIntake of dietary fiber is associated with a reduced risk of inflammatory bowel disease. β-Glucan (BG), a bioactive dietary fiber, has potential health-promoting effects on intestinal functions; however, the underlying mechanism remains unclear. Here, we explore the role of BG in ameliorating colitis by modulating key bacteria and metabolites, confirmed by multiple validation experiments and loss-of-function studies, and reveal a novel bacterial cross-feeding interaction.ResultsBG intervention ameliorates colitis and reverses Lactobacillus reduction in colitic mice, and Lactobacillus abundance was significantly negatively correlated with the severity of colitis. It was confirmed by further studies that Lactobacillus johnsonii was the most significantly enriched Lactobacillus spp. Multi-omics analysis revealed that L. johnsonii produced abundant indole-3-lactic acid (ILA) leading to the activation of aryl hydrocarbon receptor (AhR) responsible for the mitigation of colitis. Interestingly, L. johnsonii cannot utilize BG but requires a cross-feeding with Bacteroides uniformis, which degrades BG and produces nicotinamide (NAM) to promote the growth of L. johnsonii. A proof-of-concept study confirmed that BG increases L. johnsonii and B. uniformis abundance and ILA levels in healthy individuals.ConclusionsThese findings demonstrate the mechanism by which BG ameliorates colitis via L. johnsonii–ILA–AhR axis and reveal the important cross-feeding interaction between L. johnsonii and B. uniformis.BsYQ6kaZHXkFsG8eqgZ27EVideo Graphical

Metagenomic survey reveals hydrocarbon biodegradation potential of Canadian high Arctic beaches

BackgroundDecreasing sea ice coverage across the Arctic Ocean due to climate change is expected to increase shipping activity through previously inaccessible shipping routes, including the Northwest Passage (NWP). Changing weather conditions typically encountered in the Arctic will still pose a risk for ships which could lead to an accident and the uncontrolled release of hydrocarbons onto NWP shorelines. We performed a metagenomic survey to characterize the microbial communities of various NWP shorelines and to determine whether there is a metabolic potential for hydrocarbon degradation in these microbiomes.ResultsWe observed taxonomic and functional gene evidence supporting the potential of NWP beach microbes to degrade various types of hydrocarbons. The metagenomic and metagenome-assembled genome (MAG) taxonomy showed that known hydrocarbon-degrading taxa are present in these beaches. Additionally, we detected the presence of biomarker genes of aerobic and anaerobic degradation pathways of alkane and aromatic hydrocarbons along with complete degradation pathways for aerobic alkane degradation. Alkane degradation genes were present in all samples and were also more abundant (33.8 ± 34.5 hits per million genes, HPM) than their aromatic hydrocarbon counterparts (11.7 ± 12.3 HPM). Due to the ubiquity of MAGs from the genus Rhodococcus (23.8% of the MAGs), we compared our MAGs with Rhodococcus genomes from NWP isolates obtained using hydrocarbons as the carbon source to corroborate our results and to develop a pangenome of Arctic Rhodococcus. Our analysis revealed that the biodegradation of alkanes is part of the core pangenome of this genus. We also detected nitrogen and sulfur pathways as additional energy sources and electron donors as well as carbon pathways providing alternative carbon sources. These pathways occur in the absence of hydrocarbons allowing microbes to survive in these nutrient-poor beaches.ConclusionsOur metagenomic analyses detected the genetic potential for hydrocarbon biodegradation in these NWP shoreline microbiomes. Alkane metabolism was the most prevalent type of hydrocarbon degradation observed in these tidal beach ecosystems. Our results indicate that bioremediation could be used as a cleanup strategy, but the addition of adequate amounts of N and P fertilizers, should be considered to help bacteria overcome the oligotrophic nature of NWP shorelines.

Mechanism of coal pitch pre-hydrogenation catalyzed by metal-free catalytic system and preparation of mesophase pitch

Coal pitch (CP) molecules have high aromaticity, planarity and condensation degree, usually requiring hydrogenation to prepare high-quality mesophase pitch (MP). However, current hydrogenation methods often face challenges such as harsh conditions, residual ash or insufficient hydrogenation. Here, with 5 wt% tetrahydronaphthalene (THN) as the hydrogen donor, hydrogenated CP (HCP) with low ash content and high H/C was prepared at low temperature and pressure via a metal-free catalytic system with boron trifluoride ether (BF3·Et2O) as catalyst and p-toluenesulfonic acid (TsOH) as co-catalyst and 5 wt%. Subsequently, MP was prepared from the HCP, and the mechanisms of catalytic hydrogenation and the formation of mesophase macromolecules were elucidated. The characterization results indicated that CP achieved optimal hydrogenation when the molar ratio of BF3 to TsOH was 1:1. The HCP obtained under this condition can further prepare a wide-area streamlined MP. During the hydrogenation process, TsOH provided proton hydrogen to BF3, forming a complex acid that facilitated carbocation reactions between THN and CP molecules, thereby enhancing hydrogenation efficiency. However, when the molar amount of TsOH exceeded that of BF3, it would catalyze the polymerization of HCP molecules to a certain extent, reducing the hydrogenation effect. Meanwhile, it could introduce more sulfonic acid groups into the molecular structure, causing cross-linking of polycyclic aromatic hydrocarbons and excessive system viscosity during the preparation of the MP, resulting in a mosaic optical texture. This work is of significant importance for promoting the efficient hydrogenation of CP and the preparation of high-quality MP.

Novel, active, and uncultured hydrocarbon-degrading microbes in the ocean.

Given the vast quantity of oil and gas input to the marine environment annually, hydrocarbon degradation by marine microorganisms is an essential ecosystem service. Linkages between taxonomy and hydrocarbon degradation capabilities are largely based on cultivation studies, leaving a knowledge gap regarding the intrinsic ability of uncultured marine microbes to degrade hydrocarbons. To address this knowledge gap, metagenomic sequence data from the Deepwater Horizon (DWH) oil spill deep-sea plume was assembled to which metagenomic and metatranscriptomic reads were mapped. Assembly and binning produced new DWH metagenome-assembled genomes that were evaluated along with their close relatives, all of which are from the marine environment (38 total). These analyses revealed globally distributed hydrocarbon-degrading microbes with clade-specific substrate degradation potentials that have not been reported previously. For example, methane oxidation capabilities were identified in all Cycloclasticus. Furthermore, all Bermanella encoded and expressed genes for non-gaseous n-alkane degradation; however, DWH Bermanella encoded alkane hydroxylase, not alkane 1-monooxygenase. All but one previously unrecognized DWH plume member in the SAR324 and UBA11654 have the capacity for aromatic hydrocarbon degradation. In contrast, Colwellia were diverse in the hydrocarbon substrates they could degrade. All clades encoded nutrient acquisition strategies and response to cold temperatures, while sensory and acquisition capabilities were clade specific. These novel insights regarding hydrocarbon degradation by uncultured planktonic microbes provides missing data, allowing for better prediction of the fate of oil and gas when hydrocarbons are input to the ocean, leading to a greater understanding of the ecological consequences to the marine environment.IMPORTANCEMicrobial degradation of hydrocarbons is a critically important process promoting ecosystem health, yet much of what is known about this process is based on physiological experiments with a few hydrocarbon substrates and cultured microbes. Thus, the ability to degrade the diversity of hydrocarbons that comprise oil and gas by microbes in the environment, particularly in the ocean, is not well characterized. Therefore, this study aimed to utilize non-cultivation-based 'omics data to explore novel genomes of uncultured marine microbes involved in degradation of oil and gas. Analyses of newly assembled metagenomic data and previously existing genomes from other marine data sets, with metagenomic and metatranscriptomic read recruitment, revealed globally distributed hydrocarbon-degrading marine microbes with clade-specific substrate degradation potentials that have not been previously reported. This new understanding of oil and gas degradation by uncultured marine microbes suggested that the global ocean harbors a diversity of hydrocarbon-degrading bacteria, which can act as primary agents regulating ecosystem health.

Stepwise One-Shot Borylation Reactions for Intersecting DABNA Substructures Exhibiting Bright Yellow‒Green Electroluminescence with EQE Beyond 40% and Mild Roll-Off.

Boron/nitrogen (B/N)-doped polycyclic aromatic hydrocarbons (PAHs) with the multiple resonance (MR) effect are promising for organic light-emitting diodes (OLEDs) because of their narrowband emission and thermally activated delayed fluorescence (TADF) characteristics. Nevertheless, exploring the variety of such emitters is challenging because of the tricky and limited synthetic protocols. Herein, we designed a novel B/N-doped PAH, L-DABNA-1, whose backbone (L-DABNA) could not be achieved via conventional routes (e.g., one-pot borylation or one-shot borylation). We successfully synthesized it through stepwise one-shot borylations with precisely introducing decorations. The unique MR backbone with intersecting DABNA substructures sharing an aniline group, avoiding any para-N-π-B motif, allows L-DABNA-1 to maintain narrowband TADF emission while significantly redshifting to the yellow-green region with a reverse intersystem crossing rate (kRISC) of 1.28 × 105 s-1. An L-DABNA-1-based OLED device achieved a maximum external quantum efficiency (EQE) of over 40% and maintained a high EQE of 36.3% at 1000 cd m-2, with a current efficiency reaching ~170 cd A-1. This work not only demonstrated the great potential of stepwise borylations in synthesizing B/N-doped PAH backbones, expanding their chemical space, but also provided a promising pathway for exploring MR-TADF emitters at longer wavelengths.

SOURCE APPORTIONMENT OF ATMOSPHERIC AND SEDIMENTARY PAHS FROM KOLKATA, INDIA USING COMPOUND-CLASS-SPECIFIC RADIOCARBON ANALYSIS (CCSRA)

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are major air pollutants that are ubiquitously produced by the combustion of organic materials, and it is extremely important to identify their pollution sources. In this study, molecular fingerprinting and compound class-specific radiocarbon dating (CCSRA) were performed on PAHs from canal sediments and air samples collected in Kolkata, India’s third largest city (population approximately 16 million), where PAHs pollution has been a serious problem. Average PAH (Σ12-parent PAHs) concentrations in air samples were 65.1 ng m–3 in summer and 70.9 ng m–3 in winter and in canal sediments were 32.7 µg g–1, which are classified as “very high-level” pollution. Molecular fingerprinting using methyl-PAH/PAH (MPAHs/PAHs) ratios and isomer pair ratios with molecular weights of 178, 202, 228, and 276 suggested that wood and coal combustion were the dominant sources of PAHs in the sediment, and that atmospheric PAHs were influenced by oil combustion in addition to them. The fraction of contemporary carbon (ƒC) of sedimentary PAHs (0.056–0.100), together with the extremely low MPAHs/PAHs ratio results, lead to the conclusion that the major source of the high concentration of PAHs in the canals is from coal combustion. On the other hand, the ƒC of atmospheric PAHs (0.272–0.369) was close to the share of biomass fuels in India’s domestic fuel consumption in 2011 (about 35%). Furthermore, the observed ƒC-discrepancy between atmospheric and sedimentary PAHs in the same urban environment was interpreted to give an insight into the loading pathway of PAHs to canal sediments in Kolkata.

Experimental study on emissions and particulate characteristics of diesel engine fueled with plastic waste oil, acetone-butanol-ethanol and diesel blends

Plastic waste poses a significant environmental challenge due to its non-biodegradable nature and accumulation in landfills. Converting plastic waste into usable fuel could offer a promising solution for mitigating these issues while addressing the emission-related challenges of diesel engines. This study investigates the impact of plastic waste oil (WPO) obtained through pretreatment and catalytic pyrolysis, blended with acetone-butanol-ethanol (ABE) and diesel fuel, on diesel engine. The aim was to evaluate how these blends affect gaseous emissions, organic compounds, and particle-bound carbon, focusing on their potential to reduce harmful pollutants compared to pure diesel fuel. The results indicated that the ABE5W15D blend significantly reduced smoke and CO emissions by 35.7 % and 17.43 %, respectively, with a slight decrease in HC emissions. However, the ABE20W blend showed elevated NOx levels due to higher ignition delay and increased cylinder pressure. Compared to pure diesel (D100), ABE10W10D and ABE5W15D blends reduced total polycyclic aromatic hydrocarbons (PAHs) emissions by 26.8 % and 37.4 %, respectively. Naphthalene was the dominant PAH, remarkably increasing with W20D use, while longer-chain alkanes associated with lubricant oil had higher W20D emissions. The ABE5W15D blend notably reduced organic carbon (OC) emissions by approximately 38.26 % compared to D100. ABE20D exhibited lower elemental carbon (EC) emissions than D100, although it had higher EC than OC. The W20D blend resulted in larger particle diameters, whereas ABE10W10D showed lower particle counts in the 7–15 nm range. In conclusion, blending plastic waste oil with ABE and diesel fuel can effectively mitigate certain pollutants, depending on the blend composition.