Aromatic Hydrocarbon Compounds Research Articles

Analysis of Polycyclic Aromatic Hydrocarbons Using Magnetic Three-Dimensional Graphene Solid-Phase Extraction Coupled with Gas Chromatography–Mass Spectrometry

In this study, a composite material consisting of three-dimensional graphene aerogel and iron oxide nanoparticles (3DG/Fe3O4) was created and utilized for the purpose of magnetic solid-phase extraction (MSPE) of thirteen polycyclic aromatic hydrocarbon (PAH) compounds via gas chromatography–mass spectrometry/selected ion monitoring (GC-MS/SIM) analysis. The synthesized adsorbent underwent a range of characterization techniques, including scanning electron microscopy, vibrating sample magnetometry, Raman spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller, Fourier transform-infrared spectroscopy, and Barrett–Joyner–Halenda techniques, to examine its properties and morphology. The synthesized adsorbent integrates the benefits of superior adsorption capacity from modified graphene oxide (GO) with the magnetic separability of magnetite microparticles, resulting in a high adsorption capacity with easy separation from sample solutions. The efficiency of the proposed method was optimized and modeled using a central composite design (CCD), which considered the primary factors influencing it. The optimal conditions were obtained as the adsorbent dosage of 10 mg, the extraction time of 4 min, and the salt concentration of 3% w/v. The limit of detection for the target PAHs was established to range from 0.016 to 0.2 ng mL−1 in optimal conditions, exhibiting a signal-to-noise ratio of 3. The linear dynamic range spanned from 5 to 100 ng mL−1, with determination coefficients (R2) ranging from 0.9913 to 0.9997. The intra- and inter-day precisions were calculated as relative standard deviations (RSDs) equal to 3.9% and 4.7%, respectively. The proposed method was successfully applied to the determination of PAHs in water samples (tap, river, and rainwater), and recoveries in the range of 71–110% (RSDs < 5.2%, n = 3) were obtained.

Association of urinary arsenic, polycyclic aromatic hydrocarbons, and metals with cancers among the female population in the US

Cancers that primarily affect women in the US include breast, uterine, and cervical cancers. There may be associations between these different types of cancer in women and environmental pollutant exposure. This study aimed to assess seven species of arsenic, six polycyclic aromatic hydrocarbon (PAH) compounds, and fourteen different metal concentrations in urine and their correlation with cancer among women. We conducted a cross-sectional analysis using 2011--2012 to 2015-2016 National Health and Nutrition Examination Survey data (n=4,956) and logistic regression modeling of the complex weighted survey design. Breast cancer was inversely correlated with arsenocholine (3rd quantile), monomethylarsonic acid (4th quantile), manganese (4th quantile), and antimony (3rd, 4th quantiles). Cervical cancer was inversely correlated with 3-hydroxyfluorene (3rd quantile), molybdenum (2nd, 4th quantiles), antimony (3rd quantile), tin (4th quantile), and thallium (4th quantile) exposure and positively associated with arsenic acid (3rd quantile), arsenobetaine (2nd, 4th quantiles). Uterine cancer was correlated with 1-hydroxynaphthalene (3rd, 4th quantiles), 2-hydroxynaphthalene (4th quantile), 1-hydroxyphenathrene (2nd, 4th quantiles), 1-hydroxypyrene (3rd quantile), cobalt (2nd, 3rd quantiles) and inversely with mercury (4th quantile). This study determined breast cancer and arsenic and some metal species exposure, indicating an inverse association. Arsenic acid and arsenobetaine exposure showed a positive correlation with cervical cancer. For uterine cancer, the correlations for the PAH compounds and cobalt showed a positive correlation, and the arsenic species and mercury were inversely associated. Further research is required to establish or refute the findings.

Microbial Consortium HJ-SH with Very High Degradation Efficiency of Phenanthrene.

Phenanthrene (PHE) is one of the model compounds of polycyclic aromatic hydrocarbons (PAHs). In this study, a natural PHE-degrading microbial consortium, named HJ-SH, with very high degradation efficiency was isolated from soil exposed to long-term PHE contamination. The results of GC analysis showed that the consortium HJ-SH degraded 98% of 100 mg/L PHE in 3 days and 93% of 1000 mg/L PHE in 5 days, an efficiency higher than that of any other natural consortia, and even most of the engineered strains and consortia reported so far. Seven dominating strains were isolated from the microbial consortium HJ-SH, named SH-1 to SH-7, which were identified according to morphological observation and 16S rDNA sequencing as Pseudomonas sp., Stenotrophomonas sp., Delftia sp., Pseudomonas sp., Brevundimonas sp., Curtobacterium sp., and Microbacterium sp., respectively. Among all the seven single strains, SH-4 showed the strongest PHE degradation ability, and had the biggest degradation contribution. However, it is very interesting that the microbial consortium can hold its high degradation ability only with the co-existence of all these seven single strains. Moreover, HJ-SH exhibited a very high tolerance for PHE, up to 4.5 g/L, and it can degrade some other typical organic pollutants such as biphenyl, anthracene, and n-hexadecane with the degradation ratios of 93%, 92% and 70%, respectively, under 100 mg/L initial concentration in 5 days. Then, we constructed an artificial consortium HJ-7 consisting of the seven single strains, SH-1 to SH-7. After comparing the degradation ratios, cell growth, and relative degradation rates, it was concluded that the artificial consortium HJ-7 with easier reproducibility, better application stability, and larger room for modification can largely replace the natural consortium HJ-SH. In conclusion, this research provided novel tools and new insights for the bioremediation of PHE and other typical organic pollutants using microbial consortia.

Characterization, ratio analysis, and carcinogenic risk assessment of polycyclic aromatic hydrocarbon compounds bounded PM10 in a southwest of Iran

Background/objectivesA group of environmental carcinogens are polycyclic aromatic hydrocarbons (PAHs) that are formed during the incomplete combustion of organic materials. The aims of this study was evaluated the Characterization, ratio analysis, and carcinogenic risk assessment of polycyclic aromatic hydrocarbon compounds bounded PM10 in a southwest of Iran. MethodsIn this descriptive-cross-sectional study, was conducted in every 4 seasons. In each region, 20 air samples and a total of 40 samples were collected by the OMNI device in two regions. ResultsBased on result of this study in the cold season the average concentration total of PAHs was higher than in the hot season. Anthracene and fluorine with 4.70 and 4.25 ng/m3 in the cold season and naphthalene and anthracene with 4.07 and 3.48 ng/m3 in the warm season were the highest mean concentration among other organic compounds. The results of diagnostic ratios also showed that the main source PAHs of in the air of Shushtar city is fossil fuel and the use of gasoline cars. ConclusionAccording to the results the mean amount of PAHs in the cold season is higher than in the hot season, and the effects of temperature on it can aggravate these pollutants. Considering that PAHs are mainly produced as a result of the use of fossil fuels and transportation, it is necessary to pay more attention to these pollutants and control the sources of their emission. It is also necessary to create a culture in society in order to increase the use of public transportation.

Distinct laccase expression and activity profiles of Trametes versicolor facilitate degradation of benzo[a]pyrene.

A Trametes versicolor isolate from the Changbai Mountain showed promising activity in degrading benzo[a]pyrene (BaP), which is a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) compound. It was hypothesized that the T. versicolor isolate encode BaP-degrading enzymes, among which laccase is mostly sought after due to significant commercial potential. Genome of the T. versicolor isolate was sequenced and assembled, and seven laccase homologues were identified (TvLac1-7) as candidate genes potentially contributing to BaP degradation. In order to further identify the BaP responsive laccases, time-course transcriptomic and proteomic analyses were conducted in parallel on the T. versicolor isolate upon BaP treatment. Homologous laccases showed distinct expression patterns. Most strikingly, TvLac5 was rapidly induced in the secreted proteomes (secretomes), while TvLac2 was repressed. Recombinant laccase expression and biochemical characterization further showed corresponding enzymatic activity profiles, where TvLac5 was 21-fold more effective in BaP degradation compared to TvLac2. Moreover, TvLac5 also showed 3.6-fold higher BaP degrading activity compared to a commercial laccase product of T. versicolor origin. Therefore, TvLac5 was concluded to be a BaP-responsive enzyme from T. versicolor showing effective BaP degradation activity.

Novel strategy to produce polyaromatic compounds at low temperature for the production of secondary chars

The production of polyaromatic compounds during biomass thermochemical processing at temperatures over 700 °C from the secondary reactions pyrolysis vapors is a well study phenomena. These compounds are sometimes used to produce carbonaceous materials (such as carbon black, carbon nanotubes). In the case of gasification these polyaromatic compounds form tars and are a major source of problems for the operation of these reactors. In this paper we explore the use of acid impregnation, particularly using phosphoric acid, to reduce the temperature at which small polyaromatic rings are formed and released from the biomass. The acid treatment of biomass was found to increase the yield of biochar (from 17 wt% to 40 wt%) and to be an excellent source of polyaromatic compounds (close to 15 wt% on biomass dry basis). In this manuscript we explored the use of the small polyaromatic ring systems produced from the carbonization of acid-pretreated biomass as precursors for the synthesis of secondary carbons. A two-step pyrolysis process was conducted on acid-treated biomass, revealing that the volatiles produced in the first stage were primarily derived from the dehydration of anhydrosugars. In contrast, the volatiles produced in the second stage were found to be primarily composed of aromatic compounds similar to those produced in gasification processes, with low to no oxygen content. In this research, we have introduced an innovative strategy to maximize the benefits of acid-treated biomass pyrolysis by utilizing the low oxygen aromatic hydrocarbons compounds produced as a carbon source for the production of carbon nanostructures (CNS) on biochar-supported nickel catalysts. This methodology allows to produce polyaromatic compounds at very low temperature from lignocellulosic materials. This not only optimizes the utilization of biomass resources but also enhances the yield of high-value products and aligns with the principles of a circular economy.

Aromatic hydrocarbons rich bio-oil production from Miscanthus pyrolysis by coupling torrefaction and MoO3/ZSM-5 dual catalysis process

The valorization of Miscanthus pyrolysis by coupling torrefaction and MoO3/ZSM-5 dual catalysis process was studied to generate the aromatic hydrocarbons rich bio-oil, biochar, and combustible gas. With the optimal conditions of torrefied Miscanthus at 280 °C, MoO3/ZSM-5 catalysis process converted 24.17 % bio-oil, 30.27 % biochar, and 45.56 % gas. The coupled system accessed bio-oil phase deoxygenation by reducing the oxygen-containing compound content to 6.27 %. The aromatic yield reached 91.38 %, with an outstanding benzene, toluene and xylene (BTX) selectivity of 52.24 %. Isolating investigations revealed that torrefaction declined the oxygen content of Miscanthus to 5.24 %, increasing their calorific value and promoting subsequent catalytic pyrolysis through deoxygenation. When only using the ZSM-5 catalyst, the increase in torrefaction temperature enhanced aromatic hydrocarbon compounds conversion in the bio-oil, leading to a boost in their content from 55.01 % to 75.97 %. Correspondingly, MoO3 promoted deoxygenation, decreased the ketone content from 40.4 % to 21.92 %, and inhibited the generation of aldehydes. The combination of MoO3 and ZSM-5 with torrefaction delivered a superimposed effect on yielding aromatic hydrocarbons and BTX, which allowed a promising product upgrading method for obtaining high-quality bio-oil.

Spatial and Temporal variations of Organic Chemical compounds in Ambient Air from Ahmedabad City, Gujarat, India

Organic contaminants linked to atmospheric particulate matter have been a major source of worry across the world since the last decade. The ambient air samples were collected from three sites in Ahmedabad city for spatial and temporal variation using a High-Volume Air Sampler (HVAS) to examine the morphology and elemental composition of fine and ultrafine particles by using a Scanning electron microscope (SEM) and an energy dispersive X-ray system (EDAX) from PM2.5. The Si, C, O, Cl, Na, Al, K, Ca and Mg were found to be quite abundant in the EDAX spectra. Transition elements such as Ti, Zn, Cu, S and Fe were registered, indicating the influence of industry in liberating the abundance of fine and ultrafine particles. In addition, the organic chemical compounds were screened by using GC–MS. A total of 230 organic chemicals were detected, including 187 aliphatic and 43 aromatic chemical compounds at three different locations. Results show that aliphatic and aromatic hydrocarbon compounds were found maximum in the urban area followed by industrial and rural areas.

Mild Synthesis of Polychlorinated Arenes for Efficient Organic Light‐emitting Diodes with Dual Thermally Activated Delayed Fluorescence

AbstractPolychlorinated (hetero)arenes have shown great promise for organic optoelectronics applications. However, the harsh synthetic routes for polychlorinated compounds and the possible luminescence quenching from the compact intermolecular π–π stacking induced by chlorine atoms limit their investigations and applications in luminescent materials. Herein, two isomeric polychlorinated polycyclic aromatic hydrocarbon (PAH) compounds JY‐1‐Cl and JY‐2‐Cl consisting of rigidified aryl ketones and amine are designed and synthesized under mild conditions through nucleophilic chlorination intermediated by an electron donor‐acceptor complex. Among them, as a result of the strong π–π interactions induced by chlorine atoms, JY‐2‐Cl exhibits bright monomer and dimer emissions with dual thermally activated delayed fluorescence (TADF) characters. Notably, compared with the non‐chlorinated compounds, a high photoluminescence quantum yield is maintained after introducing multiple chlorine atoms into JY‐2‐Cl. The first dual‐TADF organic light‐emitting diodes are also successfully fabricated with maximum external quantum efficiency as high as 29.1 % by employing JY‐2‐Cl as emitter. This work presents a new paradigm and synthesis of polychlorinated amine‐carbonyl PAHs and demonstrates the great potential of the chlorinated materials for luminescent applications.

Mild Synthesis of Polychlorinated Arenes for Efficient Organic Light-emitting Diodes with Dual Thermally Activated Delayed Fluorescence.

Polychlorinated (hetero)arenes have shown great promise for organic optoelectronics applications. However, the harsh synthesis of polychlorinated compounds and the possible luminescence quenching from the compact intermolecular π-π stacking induced by chlorine atoms limit their investigations and applications in luminescent materials. Herein, two isomeric polychlorinated polycyclic aromatic hydrocarbon (PAH) compounds JY-1-Cl and JY-2-Cl consisting of rigidified aryl ketones and amine are designed and synthesized under mild conditions through nucleophilic chlorination intermediated by electron donor-acceptor complex. Among them, due to the strong π-π interactions induced by chlorine atoms, JY-2-Cl exhibits bright monomer and dimer emissions with dual thermally activated delayed fluorescence (TADF) characters. Notably, in compared with the non-chlorinated compounds, high photoluminescence quantum yield is well maintained after introducing multiple chlorine atoms in JY-2-Cl. Eventually, the first dual-TADF organic light-emitting diodes are also successfully fabricated with maximum external quantum efficiency as high as 29.1% employing JY-2-Cl as emitter. This work presents a new paradigm and synthesis of polychlorinated amine-carbonyl PAHs and demonstrates the great potential of the chlorinated materials for luminescent applications.

Chemical Pollutants (Aromatic Compounds and Heavy Metals) from Industrial Wastes which Impacted on Planted Vegetables

The chemical pollutants (aromatic compounds and heavy metals) in the waters of the Tigris River were studied for the two sites of the Dora power station and the site of the vegetable oil plant during the summer season of 2021. The study included measuring some physical and chemical properties such as (acid function, temperature, turbidity, total dissolved salts, magnesium, calcium, chloride and potassium and sodium and determination of heavy metals such as (lead, cadmium) and the results were (0.06 ppm lead at the cycle electricity site, 0.04 ppm lead in the vegetable oil site), (0.1 ppm cadmium at the cycle electricity site, 0.1 ppm cadmium at the vegetable oil site), the aromatic compounds of the river water were estimated, and the heavy elements of soil and plants (lead, cadmium) were estimated. The results indicated that the water quality was low in salinity and low in soda, and the results of soil tests showed that the concentrations of lead and cadmium elements were (61.75 ppm lead at the Dora electricity site, 55.11 ppm for lead in the vegetable oil site), and it was (14.45 ppm cadmium at the Dora electricity site)., 13.75 ppm for cadmium in the vegetable oil site) and thus exceeded the permissible limits of the specifications of the World Health Organization (WHO, 2003). vegetable oils site, exceeding the permissible limits of the Food and Health Organization (2007, WHO/FAO) standard of mg kg-1 dry matter. The study showed the presence of some aromatic hydrocarbon compounds in the water of the Tigris River for the two study sites, through the technique of Coupled Gas Chromatography-Mass Spectrometry (GS-MS), and the results of the examination recorded the presence of different concentrations, where the concentration of naphthalene compound reached 35 ppm and benzo compound ( ghi) perylene concentration reached 70 ppm for water, which indicates the pollution of river water, which is deposited and remains at the bottom of the river by the effect of sewage, wastes of stations and oil installations, and waste of laboratories.

Biodegradation of Polycyclic Aromatic Hydrocarbon Compound by Bacterial Cultures

In the present study biodegradation of Polycyclic Aromatic Hydrocarbon (PAH) compound Naphthalene by four bacterial cultures Bacillus subtilis PD6, Bacillussp. PD9, Enterobactersp. PD11 and Bacillussp. PD14 has been targeted. Biodegradation of Naphthalene by these four selected bacterial cultures was analysed by HPLC (High Performance Liquid Chromatography) technique. HPLC analysis revealed biodegradation of naphthalene by all the four bacterial cultures within a span of six days. Highest biodegradation 78.1% has been shown by Bacillus subtilis PD6 while other bacterial cultures Bacillus sp. PD9 has shown 77.90%, Enterobacter sp. PD11 showed 74.4% and Bacillus sp. PD14 exhibited 73.5% biodegradation of naphthalene.

Biodegradation of Polycyclic Aromatic Hydrocarbon Compound by Bacterial Cultures

Biodegradation of Polycyclic Aromatic Hydrocarbon Compound by Bacterial Cultures

Thermal maturity of crude oils in the Baiyun sag, Pearl River Mouth basin, South China Sea: Insights from biomarkers，aromatic hydrocarbon and adamantane compounds

The Baiyun Sag in the Pearl River Mouth Basin is a hydrocarbon-rich depression in which oil and natural gas fields coexist. The complex characteristics of oil and condensate in the sag have been long-term issues, and one of the questions is the formation stage of black oil, volatile oil and gas condensate in the sag. In this study, to accurately estimate the thermal maturity of oil in the Baiyun Sag, maturity parameters derived from normal alkanes, terpanes, steranes and aromatic hydrocarbons were systematically investigated. In addition, adamantane parameters were used to verify both the oil and condensate maturity. The results show that the saturated hydrocarbon biomarker parameters are not suitable for providing a complete understanding of the oil maturity in the Baiyun Sag. A qualitative evaluation method for various maturity stages of oil was proposed based on the methylphenanthrene distribution fractions, phenyldibenzothiophene maturity parameters, and diamantane concentration. Subsequently, the maturity was quantitatively evaluated using empirical equations based on methyl diamantine. The equations were selected by comparing the calculated equivalent reflectance (Rc) with the qualitatively determined maturity stage of the crude oil. Finally, the calculated vitrinite reflectance values indicated an overestimation of the maturity of light oils and condensate oils, which were thought to be produced in the late oil window (Ro: 1.0%∼1.3%) to wet gas stage (Ro: >1.3%). The new results indicate that the black oils with Rc values ranging between 0.72% and 1.05% was generated during the peak oil window. The Rc values of gas condensates in the eastern and northeastern structural belts range from 1.20% to 1.24%, suggesting that they are products of the late oil window. The maturity levels of gas condensates in the Panyu Low Uplift are the highest (Rc: 1.14%–1.46%) in the sag. They were produced in the late oil to wet gas stages. The oil maturity characteristics confirm the oil exploration potentials of the eastern and northeastern structural belts of the Baiyun Sag.

Aerobic biodegradation of phenanthrene by a newly isolated Klebsiella sp. DS-1 from wastewater

Representative polycyclic aromatic hydrocarbons (PAHs) compounds such as phenanthrene (PHE) derived from multiple anthropogenic activities are contributing to a growing number of concerns about its threats to the global water environment and human health. Microbial degradation is considered to be an increasingly promising approach for PHE removal, while effective PHE biodegraders from in situ environments are yet to be identified and their underlying degradation mechanisms still remain to be understood. Herein, a Klebsiella sp. strain DS-1 was isolated from petrochemical wastewater using PHE as the sole carbon source. The degradation efficiency of PHE was up to 88.4 % at 30 °C and pH 7 within a maximum of 9 days. DS-1 grew actively in wide ranges of environmental factors, such as pH values (5–9), temperature (20 °C–37 °C), and initial concentrations of PHE (20–200 mg/L), with the maintenance of PHE degradability. Genome analysis revealed 14 genes that were involved in PHE biodegradation by DS-1. Detection of metabolic intermediates revealed that strain DS-1 degraded PHE via the phthalic acid pathway. These findings have expanded the knowledge of Klebsiella sp. as an active PHE degrader in wastewater and indicate its potential in the bioremediation of PHE-contaminated aquatic environments.

Additive-Assisted Perylene Polymorphism Controlled via Secondary Bonding Interactions

The influence of molecular additives or impurities on crystal growth, morphology, and polymorphism has broad importance in various fields of material science and pharmaceutical engineering. There are numerous examples demonstrating the effect of impurities on the crystallization of pharmaceutical substances; however, systematic studies on the additives’ effect on crystallization and properties of organic semiconductors have not yet been reported. Here, we studied additive-assisted crystallization of a model aromatic hydrocarbon compound–perylene–to elaborate the crystal engineering tool for organic optoelectronics and to reveal the underlying mechanism. Anthracene, tetracene, 9,10-diphenylanthracene, and rubrene were used as representative additives. We found the optimal additive and conditions for perylene crystallization allowing us to control its polymorphic outcome. The addition of 9,10-diphenylanthracene was demonstrated to lead to a preferable crystallization of metastable β-form of perylene, whereas in the neat conditions, α-form was typically obtained as a stable one. The crystallization of perylene with 9,10-diphenylanthracene in high concentrations resulted in their stoichiometric co-crystallization. The perylene:9,10-diphenylanthracene co-crystal structure and optoelectronic properties were evaluated. The co-crystal demonstrated a photoluminescence quantum yield of 45% and hole mobility of 0.025 cm2/V s. The co-crystal structure analysis pointed on the stabilization of herringbone packing of perylene by interlayer C–H···π interactions, allowing the 9,10-diphenylanthracene layers to serve as the template for perylene β-polymorph nucleation. The results obtained could serve as the basis for crystallization control and engineering of high-performance materials in organic optoelectronics.

Biomarkers of Tobacco Carcinogenesis in Diverse Populations: Challenges and Opportunities

Biomarkers can provide distinct information about cancer risk factors in populations from diverse ancestries and with different exposure patterns by measuring the internal dose of carcinogens. While similar environmental exposures can lead to different cancer risks across racial or ethnic groups, seemingly different exposures can cause the same cancers because they produce the same biomarkers in the body. Smoke-related biomarkers are among the most commonly studied biomarkers in relation to cancer, and they include tobacco-specific biomarkers (nicotine metabolites and tobacco-specific nitrosamines) and biomarkers which can result from exposure to tobacco and non-tobacco pollutants (polycyclic aromatic hydrocarbon and volatile organic compounds). Biomonitoring is superior to self-reported exposure assessment because it is less prone to information and recall biases. However, biomarkers generally reflect recent exposure determined by their metabolism and half-life and how they are stored in and excreted from the body. Many biomarkers are correlated because the sources of exposure usually contain several carcinogens at the same time, making it difficult to identify specific chemicals which lead to cancer. Despite these challenges, biomarkers will continue to be essential to cancer research. Prospective studies, with detailed exposure assessment and large sample sizes from diverse backgrounds, along with studies designed to enrich the methodology of biomarker research are the necessary steps in that direction. See related article by Cigan et al., p. 306.

Characterization of Polycyclic Aromatic Hydrocarbons (PAHs) associated with fine aerosols in ambient atmosphere of high-altitude urban environment in Sikkim Himalaya

Polycyclic Aromatic Hydrocarbons (PAHs) compounds are ubiquitous in ambient air due to their persistence, carcinogenicity, and mutagenicity. Gangtok being one of the cleanest cities in India located in Eastern Himalayan region, witnesses high developmental activities with enhanced urbanization affecting the ambient air quality. The present study aims to measure PM2.5 and PAHs in the ambient atmosphere of the Sikkim Himalaya to understand the influence of natural and anthropogenic activities on aerosol loading and their chemical characteristics. The PM2.5 samples were collected and analysed for the duration from Jan 2020 to Feb 2021.The seasonal mean concentrations of PM2.5 and PAHs were observed to be high during autumn and low during summer season. Overall, the annual mean concentration of PM2.5 was found higher than the prescribed limit of World Health Organization and National Ambient Air Quality Standards. The concentration of the 16 individual PAHs were found to be highest during autumn season (55.26 ± 37.15 ng/m3). Among the different PAHs, the annual mean concentration of fluorene (3.29 ± 4.07 ng/m3) and naphthalene (1.15 ± 3.76 ng/m3) were found to be the highest and lowest, respectively. The Molecular Diagnostic Ratio (MDR) test reveals higher contribution from heavy traffic activities throughout the winter and autumn seasons. The other possible sources identified over the region are fossil fuel combustion, and biomass burning. The multivariate statistical analysis (Multifactor Principal Component Analysis) also indicates a strong association between PM2.5 /PAHs and meteorological variables across the region in different seasons. The precipitation and wind pattern during the study period suggests that major contribution of the PM2.5 and PAHs were from local sources, with minimal contribution from long-range transport. The findings are important for comprehending the trends of PAH accumulation over a high-altitude urban area, and for developing sustainable air quality control methods in the Himalayan region.

Bidirectional Regulation of NAD(P)H Quinone Dehydrogenase 1 Expression in Mouse Hepatic Stellate Cells- Acute versus Long-Term Ethanol Exposure

Conclusions: Our findings suggest that ethanol upregulates NQO1 expression by activating the AhR-Nrf2 pathway. Long-term ethanol exposure sustains low level of AhR protein and diminishes the inducibility of its target genes Nrf2 and NQO1 by BaP. These findings will contribute to understanding the synergistic toxicity of ethanol and polycyclic aromatic hydrocarbon compounds, such as BaP.

Recent allopolyploidy alters Spartina microRNA expression in response to xenobiotic-induced stress.

Environmental contamination by xenobiotics represents a major threat for natural ecosystems and public health. In response, xenobiotic detoxification is a fundamental trait of organisms for developmental plasticity and stress tolerance, but the underlying molecular mechanisms remain poorly understood in plants. To decipher this process, we explored the consequences of allopolyploidy on xenobiotic tolerance in the genus Spartina Schreb. Specifically, we focused on microRNAs (miRNAs) owing to their central function in the regulation of gene expression patterns, including responses to stress. Small RNA-Seq was conducted on the parents S. alterniflora and S. maritima, their F1 hybrid S. x townsendii and the allopolyploid S. anglica under phenanthrene-induced stress (phe), a model Polycyclic Aromatic Hydrocarbon (PAH) compound. Differentially expressed miRNAs in response to phe were specifically identified within species. In complement, the respective impacts of hybridization and genome doubling were detected, through changes in miRNA expression patterns between S. x townsendii, S. anglica and the parents. The results support the impact of allopolyploidy in miRNA-guided regulation of plant response to phe. In total, we identified 17 phe-responsive miRNAs in Spartina among up-regulated MIR156 and down-regulated MIR159. We also describe novel phe-responsive miRNAs as putative Spartina-specific gene expression regulators in response to stress. Functional validation using Arabidopsis (L.) Heynh. T-DNA lines inserted in homologous MIR genes was performed, and the divergence of phe-responsive miRNA regulatory networks between Arabidopsis and Spartina was discussed.