Background Traffic particulate matter (PM) comprises a mixture of particles from fuel combustion and wear of road pavement, tires and brakes. In countries with low winter temperatures the relative contribution of mineral-rich PM from road... more
Background Traffic particulate matter (PM) comprises a mixture of particles from fuel combustion and wear of road pavement, tires and brakes. In countries with low winter temperatures the relative contribution of mineral-rich PM from road abrasion may be especially high due to use of studded tires during winter season. The aim of the present study was to sample and characterize size-fractioned PM from two road tunnels paved with different stone materials in the asphalt, and to compare the pro-inflammatory potential of these fractions in human bronchial epithelial cells (HBEC3-KT) in relation to physicochemical characteristics. Methods The road tunnel PM was collected with a vacuum pump and a high-volume cascade impactor sampler. PM was sampled during winter, both during humid and dry road surface conditions, and before and after cleaning the tunnels. Samples were analysed for hydrodynamic size distribution, content of elemental carbon (EC), organic carbon (OC) and endotoxin, and the...
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Exposure to diesel exhaust particles (DEPs) affects endothelial function and may contribute to the development of atherosclerosis and vasomotor dysfunction. As intracellular calcium concentration [Ca] is considered important in... more
Exposure to diesel exhaust particles (DEPs) affects endothelial function and may contribute to the development of atherosclerosis and vasomotor dysfunction. As intracellular calcium concentration [Ca] is considered important in myoendothelial signalling, we explored the effects of extractable organic matter from DEPs (DEP-EOM) on [Ca] and membrane microstructure in endothelial cells. DEP-EOM of increasing polarity was obtained by pressurized sequential extraction of DEPs with -hexane (-Hex-EOM), dichloromethane (DCM-EOM), methanol, and water. Chemical analysis revealed that the majority of organic matter was extracted by the -Hex- and DCM-EOM, with polycyclic aromatic hydrocarbons primarily occurring in -Hex-EOM. The concentration of calcium was measured in human microvascular endothelial cells (HMEC-1) using micro-spectrofluorometry. The lipophilic -Hex-EOM and DCM-EOM, but not the more polar methanol- and water-soluble extracts, induced rapid [Ca] increases in HMEC-1. -Hex-EOM tri...
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Exposure to traffic-derived particulate matter (PM), such as diesel exhaust particles (DEP), is a leading environmental cause of cardiovascular disease (CVD), and may contribute to endothelial dysfunction and development of... more
Exposure to traffic-derived particulate matter (PM), such as diesel exhaust particles (DEP), is a leading environmental cause of cardiovascular disease (CVD), and may contribute to endothelial dysfunction and development of atherosclerosis. It is still debated how DEP and other inhaled PM can contribute to CVD. However, organic chemicals (OC) adhered to the particle surface, are considered central to many of the biological effects. In the present study, we have explored the ability of OC from DEP to reach the endothelium and trigger pro-inflammatory reactions, a central step on the path to atherosclerosis. Exposure-relevant concentrations of DEP (0.12 μg/cm) applied on the epithelial side of an alveolar 3D tri-culture, rapidly induced pro-inflammatory and aryl hydrocarbon receptor (AhR)-regulated genes in the basolateral endothelial cells. These effects seem to be due to soluble lipophilic constituents rather than particle translocation. Extractable organic material of DEP (DEP-EOM)...
Research Interests: Chemistry, Atherosclerosis, Cytokines, Inflammation, Air pollution, and 15 moreNanoparticles, Cell Biology, Cardiovascular disease, Medicine, Gene expression, Signal Transduction, Humans, Organic Compounds, Endothelial Cells, Vehicle Emissions, Aryl Hydrocarbon Receptor, Polycyclic Aromatic Hydrocarbons, Microvessels, Matrix Metalloproteinase, and Cyclooxygenase
Unlike previous lignin biodegradation studies, white rot fungi were used to produce functional biopolymers from Kraft lignin. Lignin-based polymers (hydrogel precursors) partially soluble in both aqueous and organic solvents were produced... more
Unlike previous lignin biodegradation studies, white rot fungi were used to produce functional biopolymers from Kraft lignin. Lignin-based polymers (hydrogel precursors) partially soluble in both aqueous and organic solvents were produced employing a relatively fast (6 days) enzymation of Kraft lignin with basidiomycetes, primarily Coriolus versicolor, pre-grown on kenaf/lignin agar followed by either vacuum evaporation or acid precipitation. After drying followed by a treatment with alkaline water, this intermediate polymer became a pH-sensitive anionic hydrogel insoluble in either aqueous or organic solvents. The yield of this polymer increased from 20 to 72 wt% with the addition of 2% dimethylsulfoxide to distilled water used as a medium. The mechanical stability and buffering capacity of this hydrogel can be adjusted by washing the intermediate polymer/hydrogel precursor prior to drying with solvents of different polarity (water, methanol or ethanol). Any of these polymers featu...
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Research Interests: Engineering, Pharmacology, Biochemistry, Genetics, Marine Biology, and 15 moreMicrobiology, Chemistry, Organic Chemistry, Biotechnology, Plant Biology, Ecology, Gas Chromatography, Lignin, CHEMICAL SCIENCES, Biotransformation, Termite Lignin Modification, DMSO, Industrial Chemistry/Chemical Engineering, Coriolus versicolor, and product analysis
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The efficiency and dynamics of simultaneous kenaf biomass decomposition by basidiomycetous fungi and actinobacteria were investigated. After 8weeks of incubation, up to 34wt.% of the kenaf biomass was degraded, with the combination of... more
The efficiency and dynamics of simultaneous kenaf biomass decomposition by basidiomycetous fungi and actinobacteria were investigated. After 8weeks of incubation, up to 34wt.% of the kenaf biomass was degraded, with the combination of fungi and bacteria being the most efficient. Lignin decomposition accounted for ∼20% of the observed biomass reduction, regardless of the culture used. The remaining 80% of biomass degradation was due to carbohydrate based polymers. Major monosaccharides were produced in tangible yields (26-38%) at different times. Glucose, fructose and xylose were then fully consumed by day 25 while some galactose persisted until day 45. Once monosaccharides were depleted, the production of laccase, manganese-dependent peroxidase and lignin peroxidase enzymes, essential for lignin decomposition, was induced. The products of lignin biodecomposition were shown to be water-soluble and characterized by thermal desorption-pyrolysis-gas chromatography.
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Research Interests: Environmental Engineering, Chemistry, Atmospheric Science, Chromatography, Mass Spectrometry, and 15 moreAtmospheric Aerosols, Ion Chromatography, Atmospheric sciences, Atmosphere, Aerosol, Gas Chromatography, Chemical Analysis, High Resolution, Amazon rainforest, Carbonaceous, Fatty Acid, Amazon basin, Organic Compound, Atmospheric Environment, and Capillary gas chromatography
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Research Interests: Engineering, Earth Sciences, Chemistry, Mass Spectrometry, Nuclear Magnetic Resonance, and 15 moreDISTRIBUTION, Models, Aerosol, Method, Aerosol Science and Technology, Gas Chromatography, Airborne Particulates, Differentiation, Efficiency, CHEMICAL SCIENCES, Fine Structure Constant, Fractionation, Distribution, Extraction Method, and Nuclear Magnetic Resonance Spectroscopy
Research Interests: Chemistry, Analytical Chemistry, Chromatography, Mass Spectrometry, Medicine, and 15 moreSample Preparation, Liquid Liquid Extraction, Data acquisition, Electron Transport, Anions, Liquid Chromatography / Electrospray Ionization Mass Spectrometry, Particulate Matter, Reproducibility of Results, Sensitivity and Specificity, Signal to Noise Ratio, Hydroxylamine, Confidence Interval, Aldehydes, electron capture, and limit of detection
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Levels of obesity in Middle Eastern countries are increasing. Phytochemicals have anti-obesogenic properties as evidenced by prevention of adipocyte differentiation and blocking triacylglyceride (TG) accumulation. In Yemen, Pulicaria... more
Levels of obesity in Middle Eastern countries are increasing. Phytochemicals have anti-obesogenic properties as evidenced by prevention of adipocyte differentiation and blocking triacylglyceride (TG) accumulation. In Yemen, Pulicaria jaubertii E. Gamal-Eldin (PJ) is a food additive and a traditional medicine. We tested the hypothesis that phytochemicals present in PJ inhibit adipocytic responses during differentiation of 3T3-L1 preadipocytes to adipocytes. Methanolic extracts of PJ did not block expression of fatty acid binding protein 4 (FABP4) a marker of differentiation but did inhibit TG accumulation. Treatment of 3T3-L1 preadipocytes increased NADPH:quinone oxidoreductase 1 (NQO1), a suppressor of TG accumulation. Further fractionation of the methanolic PJ extract with hexane and dichloromethane (DCM) demonstrated that bioactivity towards TG reduction and elevated expression of NQO1 and other antioxidant genes (glutamate cysteine ligase catalytic unit, glutathione disulfide red...
Research Interests: Biochemistry, Chemistry, Medicine, Antioxidants, Mice, and 15 moreAnimals, Antioxidant, Glutathione, Leptin, Glutathione Peroxidase, Arabic Medicine, Chemico-biological Interactions, Triglycerides, Plant extracts, Adipocytes, Gas Chromatography/mass Spectrometry, Biochemistry and cell biology, Down-Regulation, Immunoblotting, and Pulicaria
About 100 individual organic compounds were determined in urban aerosols collected at Gent, Belgium. The compounds were identified by gas chromatography–mass spectrometry, and quantitative data were obtained by gas chromatography–flame... more
About 100 individual organic compounds were determined in urban aerosols collected at Gent, Belgium. The compounds were identified by gas chromatography–mass spectrometry, and quantitative data were obtained by gas chromatography–flame ionization detection. Measurements of the particulate mass and of organic and elemental carbon mass were also made. Aerosol samples from a winter and a summer campaign were analyzed in order to examine seasonal differences. The major part of the extractable and elutable organic carbon in both winter and summer aerosols was found to correspond to an unresolved complex mixture that is typical for car exhaust. The prevailing resolved organic compounds in both seasons were n‐alkanes and fatty acids, but the distribution patterns of individual components within each class showed seasonal differences. The n‐alkane pattern for summer aerosols was clearly affected by emissions from the vegetation, while that of fatty acids revealed a lower relative abundance ...
Research Interests: Environmental Science, Geology, Chemistry, Mass Spectrometry, Multidisciplinary, and 15 moreConcentration, Atmospheric sciences, Gas Chromatography, Ozone, Geophysical, Fatty Acid, Oxidation, Organic carbon, Relative Abundance, Organic Compound, Fossil Fuel, Elemental Carbon, Organic aerosol, Polyaromatic hydrocarbons, and Distribution Pattern
Research Interests: Chemistry, Analytical Chemistry, Chromatography, Mass Spectrometry, Medicine, and 15 moreGas Chromatography, High Performance Liquid Chromatography, GAS LIQUID CHROMATOGRAPHY, High Resolution, Derivatization, Formic Acid, Liquid Chromatography, Chemical Engineering Science, Acetic Acid, LC MS, Biochemistry and cell biology, BSTFA, Dicarboxylic Acids, HPLC Chromatography, and limit of detection
Research Interests: Engineering, Chemistry, Technology, Chromatography, Medicine, and 11 moreSolid Phase Microextraction, CHEMICAL SCIENCES, Derivatization, Trace analysis, Particulate Matter, Gas Chromatography/mass Spectrometry, Reproducibility of Results, Aqueous Solution, Environmental Protection Agency, Aldehydes, and limit of detection
Research Interests: Engineering, Chemistry, Chromatography, Mass Spectrometry, Medicine, and 15 moreSample Preparation, Antioxidants, Lignans, Solid Phase Microextraction, Tandem Mass Spectrometry, High Performance Liquid Chromatography, CHEMICAL SCIENCES, High Resolution, Liquid Chromatography, Reproducibility of Results, Sensitivity and Specificity, Flax, Embryos, Lignan, and limit of detection
A stepwise analytical protocol is presented for recognition of uncharacterized organic chemical entities comprising carbonaceous air particulate matter (PM). In this method, thermal treatment of PM samples starts with thermal extraction... more
A stepwise analytical protocol is presented for recognition of uncharacterized organic chemical entities comprising carbonaceous air particulate matter (PM). In this method, thermal treatment of PM samples starts with thermal extraction (TE) using temperatures below 300 °C to evolve volatile low molecular weight (LMW) chemicals followed by pyrolysis (Py) of non-volatile high molecular weight (HMW) compounds to yield signature patterns of their decomposition products. Both volatile species and pyrolyzed products are characterized using gas chromatography (GC) with a mass spectrometric (MS) detection. The efficacy of sequential TE (at 200 and 300 °C) and Py (at 400, 500, 600, 700, 800, 900 and 1000 °C) was demonstrated on a defined mixture of LMW species and non-volatile polystyrene, a model HMW compound. When a solid matrix, in a form of silica or graphite particles, was introduced to this system, we determined that a solvent extraction (SE) applied prior to a sequential TE/Py-GC/MS sample analysis was an essential step to eliminate the analyte-matrix interactions, which hindered the vaporization of LMW compounds from a solid matrix resulting in a poor TE/Py separation. This SE/TE/Py-GC/MS method was then successfully applied to PM samples representing real-world PM matrices to discover several novel features of PM composition. HMW species were observed in both water-soluble (extracts) and unextractable (solid residues after an exhaustive solvent extraction) fractions of wood smoke and urban PM. The species evolving upon pyrolysis were associated with the corresponding precursor polymers, such as oxidized fragments of lignin, polysaccharides and lipids, in wood smoke PM and non-volatile anthropogenic hydrocarbons in urban PM. The proposed sequential SE/TE/Py-GC/MS protocol is capable of revealing otherwise unobserved chemical components while providing useful information on their interactions within a complex and poorly characterized PM matrix. Signature SE/TE/Py profiles, i.e., PM "fingerprints," provided by our approach may prove useful in source apportionment studies.
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Biodegradation of polychlorinated biphenyls (PCBs) in soil is considered to be very complex due to various physico-chemical factors involved. Isotope labelling technique is the best to trace fate of the xenobiotic in the environment. In... more
Biodegradation of polychlorinated biphenyls (PCBs) in soil is considered to be very complex due to various physico-chemical factors involved. Isotope labelling technique is the best to trace fate of the xenobiotic in the environment. In this work, the uniformly 14C-labelled PCB congener 11 (3,3'-chlorobiphenyl) was chosen as a low chlorinated coplanar biphenyl which was assumed to be readily degraded by microorganisms. Pleurotus ostreatus and two Pseudomonas species, representing white rot fungi and soil bacteria were used separately or in a consortium. The amount of liberated 14CO2 and radio-HPLC, HPLC, GC-MS, and radio-TLC analyses of extracts at the end of a two-month experiment showed that the mineralization of PCB 11 was < 0.4%, volatilization < 3.1%, and 30% of radioactivity was irreversibly bound to the soil matrix. The respective contents of all intermediate metabolites were 4.7 to 10.5 and 2.5 to 2.7% where Pseudomonas alcaligenes alone or in combination with P. putida was applied. 3-Chlorobenzoic acid was the major biodegradation product.
Research Interests: Chemistry, Chromatography, Kinetics, Environmental Chemistry, Biodegradation, and 12 moreWhite Rot Fungi, Pseudomonas, Polychlorinated Biphenyls, Pseudomonas putida, Soil Bacteria, Polychlorinated Biphenyl, Pleurotus, Biotransformation, Gas Chromatography/mass Spectrometry, Alcaligenes, Soil Pollutants, and Biphenyl
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Triacyl glycerides (TGs) are naturally occurring oils produced by a significant variety of crops, microorganisms (bacteria and algae), and animals (certain fats). The diversity and prevalence of the sources of these compounds suggest that... more
Triacyl glycerides (TGs) are naturally occurring oils produced by a significant variety of crops, microorganisms (bacteria and algae), and animals (certain fats). The diversity and prevalence of the sources of these compounds suggest that they may serve as an attractive alternative to crude oil as the feedstock for the production of transportation fuels and certain industrial chemicals — organic compounds
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Epidemiological and toxicological studies correlate the adverse health effects of particulate matter (PM) with the available information regarding their chemical characterization, which has focused on nonpolar organics (e.g., polycyclic... more
Epidemiological and toxicological studies correlate the adverse health effects of particulate matter (PM) with the available information regarding their chemical characterization, which has focused on nonpolar organics (e.g., polycyclic aromatic hydrocarbons [PAHs]), which are limited to 15 to 50% of total organic carbon. To study both polar and nonpolar species, we have employed hot pressurized (liquid) water for the fractionation of diesel exhaust and wood smoke PM. In agreement with the results of previous studies, nonpolar fractions from both PM samples showed strong cytotoxicity (cell viability decreased to 50–60%) corresponding to the presence of PAHs. Surprisingly, similar decreases in cell viability were also found in polar fractions (50°C) from both diesel exhaust and wood smoke PM. The midpolarity fractions (100−150°C) from wood smoke PM also displayed high cytotoxicity corresponding to methoxyphenols and oxy‐PAHs. Although the midpolarity fractions from diesel exhaust PM ...
Research Interests: Chemistry, Environmental Chemistry, Cytotoxicity, Medicine, Biological Sciences, and 15 moreCercopithecus aethiops, Environmental Sciences, Toxicity, Escherichia coli, Vehicle Emissions, Animals, Smoke, CHEMICAL SCIENCES, Pressure, Diesel Fuel, Fractionation, Environmental, Cell Survival, Air Pollutants, and Mutagenicity tests
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Research Interests: Environmental Science, Chemistry, Biomass, Modeling, Combustion, and 15 moreEnvironmental Monitoring, Environmental Chemistry, Medicine, Multidisciplinary, Environmental science and technology, Dep, Diesel engine, Diesel Fuel, Biomass burning, Functional Group, Organic Matter, Environmental, Air Pollutants, Elemental Carbon, and Diesel particulate filter
Elevated levels of trans-4-hydroxy-2-nonenal (HNE) are observed in brain tissues in patients with neurodegenerative diseases. Although astrocytes are known to play a crucial role in regulating and supporting neuronal processes, their... more
Elevated levels of trans-4-hydroxy-2-nonenal (HNE) are observed in brain tissues in patients with neurodegenerative diseases. Although astrocytes are known to play a crucial role in regulating and supporting neuronal processes, their capacity to detoxify HNE is unknown. In this work, we examined the extent to which HNE undergoes phase I and phase II metabolism in astrocytes. Murine astrocytes were exposed to three different concentrations of HNE. The loss of HNE was approximately 90%, 80%, and 70% for 1, 5, and 15 microM HNE, respectively, following a 10 min incubation. The expected metabolites trans-4-hydroxy-2-nonenoic acid (HNEAcid), (4-hydroxynonanal-3-yl)glutathione (GSHNE), and (1,4-dihydroxynonane-3-yl)glutathione (GSDHN) accounted for 90% of HNE lost at 1 microM HNE. However, when astrocytes were exposed to 5 and 15 microM HNE, those metabolites accounted only for 50% and 17%, respectively. Binding to macromolecules accounted for only 5-10% of HNE loss. Furthermore, depletion of GSH content had only a small effect on HNE metabolism without elevating HNE oxidation and suggests that other unidentified metabolic pathways are functioning. We identified two novel metabolites of HNE, gamma-nonalactone and the potent pyrrole forming compound, 4-oxo-nonanal (ONA). Occurrence of 1,4-dihydroxynonene was observed as well. These data suggest that the biotransformation of HNE yields products with differing or enhanced toxicity, as well as nontoxic products.