scholarly journals Model Combustion-Generated Particulate Matter Containing Persistent Free Radicals Redox Cycle to Produce Reactive Oxygen Species

2013 ◽  
Vol 26 (12) ◽  
pp. 1862-1871 ◽  
Author(s):  
Matthew A. Kelley ◽  
Valeria Y. Hebert ◽  
Taylor M. Thibeaux ◽  
Mackenzie A. Orchard ◽  
Farhana Hasan ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Particulate Matter ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Redox Cycle

scholarly journals Quantification of environmentally persistent free radicals and reactive oxygen species in atmospheric aerosol particles

2016 ◽  
Author(s):  
Andrea M. Arangio ◽  
Haijie Tong ◽  
Joanna Socorro ◽  
Ulrich Pöschl ◽  
Manabu Shiraiwa
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Particulate Matter ◽  
Aerosol Particles ◽  
Reactive Oxygen ◽  
Organic Radicals ◽  
Epr Spectra ◽  
Coarse Particles ◽  
Oxygen Species ◽  
Organic Hydroperoxides

Abstract. Fine particulate matter plays a central role in adverse health effects of air pollution. Inhalation and deposition of aerosol particles in the respiratory tract can lead to the release of reactive oxygen species (ROS), which may cause oxidative stress. In this study, we have detected and quantified a wide range of particle-associated radicals using electron paramagnetic resonance (EPR) spectroscopy. Ambient particle samples were collected using a cascade impactor at a semi-urban site in central Europe, Mainz, Germany in May–June 2015. Concentrations of environmentally persistent free radicals (EPFR), most likely semiquinone radicals, were found to be in the range of (1–7) × 1011 spins µg−1 for particles in the accumulation mode, whereas coarse particles with a diameter larger than 1 µm did not contain substantial amounts of EPFR. Using a spin trapping technique followed by deconvolution of EPR spectra, we have also characterized and quantified ROS including OH, superoxide (O2−) and carbon- and oxygen-centred organic radicals, which were released upon extraction of the particle samples in water. Total ROS amounts of (0.1–3) × 1011 spins µg−1 were released by submicron particle samples and the relative contributions of OH, O2−, C-centred and O-centred organic radicals were ~11–31 %, ~2–8 %, ~41–72 % and ~0–25 %, respectively, depending on particle sizes. OH was the dominant species for coarse particles. Based on comparisons of the EPR spectra of ambient particulate matter with those of mixtures of organic hydroperoxides, quinones and iron ions followed by chemical analysis using liquid chromatography mass spectrometry (LC-MS), we suggest that the particle-associated ROS were formed by decomposition of organic hydroperoxides interacting with transition metal ions and quinones contained in atmospheric humic-like substances (HULIS).

scholarly journals Quantification of environmentally persistent free radicals and reactive oxygen species in atmospheric aerosol particles

2016 ◽  
Vol 16 (20) ◽  
pp. 13105-13119 ◽  
Author(s):  
Andrea M. Arangio ◽  
Haijie Tong ◽  
Joanna Socorro ◽  
Ulrich Pöschl ◽  
Manabu Shiraiwa
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Particulate Matter ◽  
Aerosol Particles ◽  
Reactive Oxygen ◽  
Organic Radicals ◽  
Epr Spectra ◽  
Coarse Particles ◽  
Oxygen Species ◽  
Organic Hydroperoxides

Abstract. Fine particulate matter plays a central role in the adverse health effects of air pollution. Inhalation and deposition of aerosol particles in the respiratory tract can lead to the release of reactive oxygen species (ROS), which may cause oxidative stress. In this study, we have detected and quantified a wide range of particle-associated radicals using electron paramagnetic resonance (EPR) spectroscopy. Ambient particle samples were collected using a cascade impactor at a semi-urban site in central Europe, Mainz, Germany, in May–June 2015. Concentrations of environmentally persistent free radicals (EPFR), most likely semiquinone radicals, were found to be in the range of (1–7)  × 1011 spins µg−1 for particles in the accumulation mode, whereas coarse particles with a diameter larger than 1 µm did not contain substantial amounts of EPFR. Using a spin trapping technique followed by deconvolution of EPR spectra, we have also characterized and quantified ROS, including OH, superoxide (O2−) and carbon- and oxygen-centered organic radicals, which were formed upon extraction of the particle samples in water. Total ROS amounts of (0.1–3)  × 1011 spins µg−1 were released by submicron particle samples and the relative contributions of OH, O2−, C-centered and O-centered organic radicals were ∼  11–31, ∼  2–8, ∼  41–72 and ∼  0–25 %, respectively, depending on particle sizes. OH was the dominant species for coarse particles. Based on comparisons of the EPR spectra of ambient particulate matter with those of mixtures of organic hydroperoxides, quinones and iron ions followed by chemical analysis using liquid chromatography mass spectrometry (LC-MS), we suggest that the particle-associated ROS were formed by decomposition of organic hydroperoxides interacting with transition metal ions and quinones contained in atmospheric humic-like substances (HULIS).

Model Particulate Matter Containing Persistent Free Radicals Exhibit Reactive Oxygen Species Production

2011 ◽  
Vol 51 ◽  
pp. S134 ◽  
Author(s):  
Matthew a Kelley ◽  
Taylor Thibeaux ◽  
Valeria Hebert ◽  
Stephania a Cormier ◽  
Slawo Lomnicki ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Particulate Matter ◽  
Reactive Oxygen Species Production ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Species Production

scholarly journals Environmentally persistent free radicals are ubiquitous in wildfire charcoals and remain stable for years

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Gabriel Sigmund ◽  
Cristina Santín ◽  
Marc Pignitter ◽  
Nathalie Tepe ◽  
Stefan H. Doerr ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Reactive Oxygen ◽  
Resonance Spectroscopy ◽  
Oxygen Species ◽  
Pyrogenic Carbon ◽  
Spin Resonance ◽  
Long Time ◽  
High Concentrations

AbstractGlobally landscape fires produce about 256 Tg of pyrogenic carbon or charcoal each year. The role of charcoal as a source of environmentally persistent free radicals, which are precursors of potentially harmful reactive oxygen species, is poorly constrained. Here, we analyse 60 charcoal samples collected from 10 wildfires, that include crown as well as surface fires in forest, shrubland and grassland spanning different boreal, temperate, subtropical and tropical climate. Using electron spin resonance spectroscopy, we measure high concentrations of environmentally persistent free radicals in charcoal samples, much higher than those found in soils. Concentrations increased with degree of carbonization and woody fuels favoured higher concentrations. Moreover, environmentally persistent free radicals remained stable for an unexpectedly long time of at least 5 years. We suggest that wildfire charcoal is an important global source of environmentally persistent free radicals, and therefore potentially of harmful reactive oxygen species.

scholarly journals Generation of reactive oxygen species by promoting the Cu(II)/Cu(I) redox cycle with reducing agents in aerobic aqueous solution

2018 ◽  
Vol 78 (6) ◽  
pp. 1390-1399 ◽  
Author(s):  
Wenshu Li ◽  
Peng Zhou ◽  
Jing Zhang ◽  
Yongli Zhang ◽  
Gucheng Zhang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Aqueous Solution ◽  
Superoxide Radical ◽  
Reactive Oxygen ◽  
Reducing Agents ◽  
Oxygen Species ◽  
Redox Cycle ◽  
Copper Species ◽  
Chain Reactions ◽  
H2o2 Generation

Abstract This study investigated the generation of reactive oxygen species (ROS) (O2−•, H2O2, and HO•) by promoting the Cu(II)/Cu(I) redox cycle with certain reducing agents (RAs) in aerobic aqueous solution, and benzoic acid (BA) was employed as indicator for the hydroxyl radical (HO•). Hydroxylamine (HA) can reduce Cu(II) to Cu(I) to induce chain reactions of copper species resulting in the generation of the superoxide radical (O2−•) and hydrogen peroxide (H2O2), and the intermediate Cu(I) can further activate H2O2 via a Fenton-like reaction to produce HO•, creating the remarkable BA degradation. O2 is indispensable, and unprotonated HA is the motive power in the O2/Cu/HA system. Moreover, pH is a crucial factor of the O2/Cu/HA system due to the protonated HA not being able to reduce Cu(II) into Cu(I). The oxidation of HA can be effectively induced by trace amounts of Cu(II), and both a higher HA dosage and a higher Cu(II) dosage can enhance H2O2 generation and BA degradation. In addition, some other RAs that can reduce Cu(II) into Cu(I) could replace HA in the O2/Cu/HA system to induce the generation of these ROS in aerobic aqueous solution.

Diagnostic Range Ionizing Radiation and Reactive Oxygen Species Production: an Initial Experience

2021 ◽  
Vol 11 (5) ◽  
Author(s):  
Sirohi Shikha ◽  
Tandon Prof. Anupama ◽  
Banerjee Prof. B.D. ◽  
Kumar Ranjeet
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Ionizing Radiation ◽  
Venous Blood ◽  
Radiation Detection ◽  
Control Sample ◽  
Reactive Oxygen ◽  
P Value ◽  
Oxygen Species ◽  
Mdct Examination

Radiation is a common occurrence in our daily lives that comes from both natural and man-made sources. Ionizing Radiation (IR) causes damage either directly or indirectly through the generation of reactive oxygen species (ROS). Oxidative damage to DNA, lipids, proteins, and many metabolites occurs through a complex series of processes that are enhanced by endogenous signalling which is activated by free radicals. Though literature is abundant on ROS and antioxidants at high doses, no study to the best of our knowledge has assessed the ROS levels after Multi Detector Computed Tomography (MDCT) examination (i.e. in diagnostic range radiation). The aim of the present study was to assess the production of ROS after diagnostic level radiation by MDCT examination and at 24 hour follow up. The study involved fifty patients posted for clinically indicated MDCT which were recruited. The average radiation dose was 2-9 mGy. Three blood samples were drawn, one prior to CT (control sample), within half an hour of CT (post CT) and 24 hrs after CT. 3 ml venous blood was withdrawn in aseptic conditions and immediately serum was isolated for ROS assessment. The blood examination results were compared in immediate and post 24 hour after MDCT and both were compared with control values and correlated with radiation parameters. Our results have shown a significant increase in ROS level in immediate post CT samples compared to prior CT scan samples (control) (p value <0.0001). The ROS levels reduced at 24 hours compared to immediate post CT, however they were still higher than control values. Our findings reflect that there is a rapid increase in free radicals production in the mitochondria after diagnostic level radiation. Detection of higher ROS levels at 24 hours suggests incomplete repair with the presence of some residual oxidative species at 24 hours.

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