Science.gov

Sample records for gaseous nox species

  1. NOx formation in combustion of gaseous fuel in ejection burner

    NASA Astrophysics Data System (ADS)

    Rimár, Miroslav; Kulikov, Andrii

    2016-06-01

    The aim of this work is to prepare model for researching of the formation in combustion of gaseous fuels. NOx formation is one of the main ecological problems nowadays as nitrogen oxides is one of main reasons of acid rains. The ANSYS model was designed according to the calculation to provide full combustion and good mixing of the fuel and air. The current model is appropriate to research NOx formation and the influence of the different principles of NOx reduction method. Applying of designed model should spare both time of calculations and research and also money as you do not need to measure the burner characteristics.

  2. Low NOx heavy fuel combustor concept program addendum: Low/mid heating value gaseous fuel evaluation

    NASA Technical Reports Server (NTRS)

    Novick, A. S.; Troth, D. L.

    1982-01-01

    The combustion performance of a rich/quench/lean (RQL) combustor was evaluated when operated on low and mid heating value gaseous fuels. Two synthesized fuels were prepared having lower heating values of 10.2 MJ/cu m. (274 Btu/scf) and 6.6 MJ/cu m (176 Btu/scf). These fuels were configured to be representative of actual fuels, being composed primarily of nitrogen, hydrogen, carbon monoxide, and carbon dioxide. A liquid fuel air assist fuel nozzle was modified to inject both of the gaseous fuels. The RQL combustor liner was not changed from the configuration used when the liquid fuels were tested. Both gaseous fuels were tested over a range of power levels from 50 percent load to maximum rated power of the DDN Model 570-K industrial gas turbine engine. Exhaust emissions were recorded for four power level at several rich zone equivalence ratios to determine NOx sensitivity to the rich zone operating point. For the mid Btu heating value gas, ammonia was added to the fuel to simulate a fuel bound nitrogen type gaseous fuel. Results at the testing showed that for the low heating value fuel NOx emissions were all below 20 ppmc and smoke was below a 10 smoke number. For the mid heating value fuel, NOx emissions were in the 50 to 70 ppmc range with the smoke below a 10 smoke number.

  3. The selectivity of Vibrio cholerae H-NOX for gaseous ligands follows the "sliding scale rule" hypothesis. Ligand interactions with both ferrous and ferric Vc H-NOX.

    PubMed

    Wu, Gang; Liu, Wen; Berka, Vladimir; Tsai, Ah-lim

    2013-12-31

    Vc H-NOX (or VCA0720) is an H-NOX (heme-nitric oxide and oxygen binding) protein from facultative aerobic bacterium Vibrio cholerae. It shares significant sequence homology with soluble guanylyl cyclase (sGC), a NO sensor protein commonly found in animals. Similar to sGC, Vc H-NOX binds strongly to NO and CO with affinities of 0.27 nM and 0.77 μM, respectively, but weakly to O2. When positioned on a "sliding scale" plot [Tsai, A.-l., et al. (2012) Biochemistry 51, 172-186], the line connecting log K(D)(NO) and log K(D)(CO) of Vc H-NOX can almost be superimposed with that of Ns H-NOX. Therefore, the measured affinities and kinetic parameters of gaseous ligands to Vc H-NOX provide more evidence to validate the "sliding scale rule" hypothesis. Like sGC, Vc H-NOX binds NO in multiple steps, forming first a six-coordinate heme-NO complex at a rate of 1.1 × 10(9) M(-1) s(-1), and then converts to a five-coordinate heme-NO complex at a rate that is also dependent on NO concentration. Although the formation of oxyferrous Vc H-NOX cannot be detected at a normal atmospheric oxygen level, ferrous Vc H-NOX is oxidized to the ferric form at a rate of 0.06 s(-1) when mixed with O2. Ferric Vc H-NOX exists as a mixture of high- and low-spin states and is influenced by binding to different ligands. Characterization of both ferric and ferrous Vc H-NOX and their complexes with various ligands lays the foundation for understanding the possible dual roles in gas and redox sensing of Vc H-NOX.

  4. Selectivity of Vibrio cholerae H-NOX for Gaseous Ligands Follows “Sliding Scale Rule” Hypothesis

    PubMed Central

    Wu, Gang; Liu, Wen; Berka, Vladimir; Tsai, Ah-lim

    2014-01-01

    Vc H-NOX (or VCA0720) is an H-NOX (heme-nitric oxide and oxygen binding) protein from facultative aerobic bacterium Vibrio cholerae. It shares significant sequence homology with soluble guanylyl cyclase (sGC), a NO sensor protein commonly found in animals. Similar to sGC, Vc H-NOX binds strongly to NO and CO with affinities of 0.27 nM and 0.77 μM, respectively, but weakly to O2. When positioned in “sliding scale” plot {Tsai, A.-L. et. al. (2012) Biochemistry, 51, pp172-86}, the line connecting logKD(NO) and logKD(CO) of Vc H-NOX is almost superimposable with that of Ns H-NOX. Therefore, the measured affinities and kinetic parameters of gaseous ligands to Vc H-NOX provide more evidence to validate the “sliding scale rule” hypothesis. Like sGC, Vc H-NOX binds NO in multiple steps, forming first a 6-coordinate heme-NO complex with a rate of 1.1 × 109 M−1s−1, and then converts to a 5c heme-NO complex at a rate also dependent on [NO]. Although the formation of oxyferrous Vc H-NOX is not detectable under normal atmospheric oxygen level, ferrous Vc H-NOX is oxidized to ferric form at a rate of 0.06 s−1 when mixed with O2. Ferric Vc H-NOX exists as a mixture of high- and low-spin states and is influenced by binding to different ligands. Characterization of both ferric and ferrous Vc H-NOX and their complexes with various ligands lay the foundation for understanding the possible dual roles in gas and redox sensing of Vc H-NOX. PMID:24351060

  5. Reactive Oxygen Species Derived from NOX3 and NOX5 Drive Differentiation of Human Oligodendrocytes

    PubMed Central

    Accetta, Roberta; Damiano, Simona; Morano, Annalisa; Mondola, Paolo; Paternò, Roberto; Avvedimento, Enrico V.; Santillo, Mariarosaria

    2016-01-01

    Reactive oxygen species (ROS) are signaling molecules that mediate stress response, apoptosis, DNA damage, gene expression and differentiation. We report here that differentiation of oligodendrocytes (OLs), the myelin forming cells in the CNS, is driven by ROS. To dissect the OL differentiation pathway, we used the cell line MO3-13, which display the molecular and cellular features of OL precursors. These cells exposed 1–4 days to low levels of H2O2 or to the protein kinase C (PKC) activator, phorbol-12-Myristate-13-Acetate (PMA) increased the expression of specific OL differentiation markers: the specific nuclear factor Olig-2, and Myelin Basic Protein (MBP), which was processed and accumulated selectively in membranes. The induction of differentiation genes was associated with the activation of ERK1-2 and phosphorylation of the nuclear cAMP responsive element binding protein 1 (CREB). PKC mediates ROS-induced differentiation because PKC depletion or bis-indolyl-maleimide (BIM), a PKC inhibitor, reversed the induction of differentiation markers by H2O2. H2O2 and PMA increased the expression of membrane-bound NADPH oxidases, NOX3 and NOX5. Selective depletion of these proteins inhibited differentiation induced by PMA. Furthermore, NOX5 silencing down regulated NOX3 mRNA levels, suggesting that ROS produced by NOX5 up-regulate NOX3 expression. These data unravel an elaborate network of ROS-generating enzymes (NOX5 to NOX3) activated by PKC and necessary for differentiation of OLs. Furthermore, NOX3 and NOX5, as inducers of OL differentiation, represent novel targets for therapies of demyelinating diseases, including multiple sclerosis, associated with impairment of OL differentiation. PMID:27313511

  6. Reactive Oxygen Species Derived from NOX3 and NOX5 Drive Differentiation of Human Oligodendrocytes.

    PubMed

    Accetta, Roberta; Damiano, Simona; Morano, Annalisa; Mondola, Paolo; Paternò, Roberto; Avvedimento, Enrico V; Santillo, Mariarosaria

    2016-01-01

    Reactive oxygen species (ROS) are signaling molecules that mediate stress response, apoptosis, DNA damage, gene expression and differentiation. We report here that differentiation of oligodendrocytes (OLs), the myelin forming cells in the CNS, is driven by ROS. To dissect the OL differentiation pathway, we used the cell line MO3-13, which display the molecular and cellular features of OL precursors. These cells exposed 1-4 days to low levels of H2O2 or to the protein kinase C (PKC) activator, phorbol-12-Myristate-13-Acetate (PMA) increased the expression of specific OL differentiation markers: the specific nuclear factor Olig-2, and Myelin Basic Protein (MBP), which was processed and accumulated selectively in membranes. The induction of differentiation genes was associated with the activation of ERK1-2 and phosphorylation of the nuclear cAMP responsive element binding protein 1 (CREB). PKC mediates ROS-induced differentiation because PKC depletion or bis-indolyl-maleimide (BIM), a PKC inhibitor, reversed the induction of differentiation markers by H2O2. H2O2 and PMA increased the expression of membrane-bound NADPH oxidases, NOX3 and NOX5. Selective depletion of these proteins inhibited differentiation induced by PMA. Furthermore, NOX5 silencing down regulated NOX3 mRNA levels, suggesting that ROS produced by NOX5 up-regulate NOX3 expression. These data unravel an elaborate network of ROS-generating enzymes (NOX5 to NOX3) activated by PKC and necessary for differentiation of OLs. Furthermore, NOX3 and NOX5, as inducers of OL differentiation, represent novel targets for therapies of demyelinating diseases, including multiple sclerosis, associated with impairment of OL differentiation. PMID:27313511

  7. Extension of JAGUAR Procedures for New Gaseous and Condensed Species

    NASA Astrophysics Data System (ADS)

    Stiel, Leonard; Baker, Ernest; Murphy, Daniel

    2011-06-01

    JAGUAR is a highly efficient and accurate thermochemical equilibrium program for the detonation properties of explosives. In previous studies equation of state EXP-6 parameters for H-CN-O gaseous explosives product species have been optimized with available individual species Hugoniot data. The Jaguar library also includes solid and liquid properties for carbon and aluminum, silicon, and boron compounds. In this study the Jaguar property library has been expanded to include additional gaseous, liquid, and solid detonation products. New EXP-6 parameters for gaseous fluorine and chlorine compounds have been established through theoretical procedures, and by analyses of Hugoniot data for the actual species or for reactants which decompose into these compounds. Properties for additional condensed species have also been analyzed and added to the library. Extensive tests have beeb performed to determine the accuracy of calculated detonation properties in comparison to experimental data. The authors gratefully acknowledge the support of the Institute for Multi Scale Reactive Modeling.

  8. Extension of jaguar procedures for new gaseous species

    NASA Astrophysics Data System (ADS)

    Stiel, Leonard; Baker, Ernest L.; Murphy, Daniel

    2012-03-01

    Jaguar is a highly efficient and accurate thermochemical equilibrium program for the detonation properties of explosives. In previous studies, equation of state Exp-6 parameters for H-C-N-O gaseous explosives product species have been optimized with available individual species Hugoniot data. The Jaguar library also includes solid and liquid properties for carbon and aluminum, silicon, and boron compounds. In this study the Jaguar property library has been expanded to include additional gaseous detonation products. New Exp-6 parameters for gaseous fluorine and chlorine compounds have been established by analyses of Hugoniot data for the actual species or for reactants which decompose into these compounds. Tests with data for explosives and additional compounds containing fluorine and chlorine have been performed to determine the accuracy of calculated detonation properties in comparison to experimental data.

  9. Tks5-dependent, Nox-mediated Generation of Reactive Oxygen Species is Necessary for Invadopodia Formation*

    PubMed Central

    Diaz, Begoña; Shani, Gidon; Pass, Ian; Anderson, Diana; Quintavalle, Manuela; Courtneidge, Sara A.

    2009-01-01

    Invadopodia are actin-rich membrane protrusions of cancer cells which facilitate pericellular proteolysis and invasive behavior. We show here that reactive oxygen species (ROS) generated by the NADPH oxidase (Nox) system are necessary for invadopodia formation and function. The invadopodia protein Tks5 is structurally related to p47phox, a Nox component in phagocytic cells. Knockdown of Tks5 reduces total ROS levels in cancer cells. Furthermore, Tks5 and p22phox can associate with each other, suggesting that Tks5 is part of the Nox complex. Tyrosine phosphorylation of Tks5 and Tks4, but not other Src substrates, is reduced by Nox inhibition. We propose that Tks5 facilitates the production of ROS necessary for invadopodia formation, and that in turn ROS modulates Tks5 tyrosine phosphorylation in a positive feedback loop. PMID:19755709

  10. Relationship of peroxyacetyl nitrate to active and total odd nitrogen at northern high latitudes: influence of reservoir species on NOx and O3.

    PubMed

    Singh, H B; Herlth, D; O'Hara, D; Zahnle, K; Bradshaw, J D; Sandholm, S T; Talbot, R; Crutzen, P J; Kanakidou, M

    1992-10-30

    Measurements of peroxyacetyl nitrate (PAN), NO, NO2, HNO3, NOy (total odd nitrogen), and O3 were made in the high-latitude troposphere over North America and Greenland (35 degrees to 82 degrees N) during the Arctic Boundary Layer Expedition (ABLE 3A) (July-August 1988) throughout 0-to 6-km altitudes. These data are analyzed to quantitatively describe the relationships between various odd nitrogen species and assess their significance to global tropospheric chemistry. In the free troposphere, PAN was as much as 25 times more abundant than NOx. PAN to NOx ratio increased with increasing altitude and latitude. PAN was found to be the single most abundant reactive nitrogen species in the free troposphere and constituted a major fraction of NOy, PAN to NOy ratios were about 0.1 in the boundary layer and increased to 0.4 in the free troposphere. A 2-D global photochemical model with C1-C3 hydrocarbon chemistry is used to compare model predictions with measured results. A sizable portion (approximately 50%) of the gaseous reactive nitrogen budget is unaccounted for, and unknown organic nitrates and pernitrates are expected to be present. Model calculations (August 1, 70 degrees N) show that a major fraction of the observed NOx (50 to 70% of median) may find its source in the available PAN reservoir. PAN and the unknown reservoir species may have the potential to control virtually the entire NOx availability of the high latitude troposphere. It is predicted that the summer NOx and O3 mixing ratios in the Arctic/sub-Arctic troposphere would be considerably lower in the absence of the ubiquitous PAN reservoir. Conversely, this PAN reservoir may be responsible for the observed temporal increase in tropospheric O3 at high latitudes.

  11. Relationship of peroxyacetyl nitrate to active and total odd nitrogen at northern high latitudes: influence of reservoir species on NOx and O3

    NASA Technical Reports Server (NTRS)

    Singh, H. B.; Herlth, D.; O'Hara, D.; Zahnle, K.; Bradshaw, J. D.; Sandholm, S. T.; Talbot, R.; Crutzen, P. J.; Kanakidou, M.

    1992-01-01

    Measurements of peroxyacetyl nitrate (PAN), NO, NO2, HNO3, NOy (total odd nitrogen), and O3 were made in the high-latitude troposphere over North America and Greenland (35 degrees to 82 degrees N) during the Arctic Boundary Layer Expedition (ABLE 3A) (July-August 1988) throughout 0-to 6-km altitudes. These data are analyzed to quantitatively describe the relationships between various odd nitrogen species and assess their significance to global tropospheric chemistry. In the free troposphere, PAN was as much as 25 times more abundant than NOx. PAN to NOx ratio increased with increasing altitude and latitude. PAN was found to be the single most abundant reactive nitrogen species in the free troposphere and constituted a major fraction of NOy, PAN to NOy ratios were about 0.1 in the boundary layer and increased to 0.4 in the free troposphere. A 2-D global photochemical model with C1-C3 hydrocarbon chemistry is used to compare model predictions with measured results. A sizable portion (approximately 50%) of the gaseous reactive nitrogen budget is unaccounted for, and unknown organic nitrates and pernitrates are expected to be present. Model calculations (August 1, 70 degrees N) show that a major fraction of the observed NOx (50 to 70% of median) may find its source in the available PAN reservoir. PAN and the unknown reservoir species may have the potential to control virtually the entire NOx availability of the high latitude troposphere. It is predicted that the summer NOx and O3 mixing ratios in the Arctic/sub-Arctic troposphere would be considerably lower in the absence of the ubiquitous PAN reservoir. Conversely, this PAN reservoir may be responsible for the observed temporal increase in tropospheric O3 at high latitudes.

  12. Reactive Oxygen Species, Vascular Noxs, and Hypertension: Focus on Translational and Clinical Research

    PubMed Central

    Montezano, Augusto C.

    2014-01-01

    Abstract Significance: Reactive oxygen species (ROS) are signaling molecules that are important in physiological processes, including host defense, aging, and cellular homeostasis. Increased ROS bioavailability and altered redox signaling (oxidative stress) have been implicated in the onset and/or progression of chronic diseases, including hypertension. Recent Advances: Although oxidative stress may not be the only cause of hypertension, it amplifies blood pressure elevation in the presence of other pro-hypertensive factors, such as salt loading, activation of the renin-angiotensin-aldosterone system, and sympathetic hyperactivity, at least in experimental models. A major source for ROS in the cardiovascular-renal system is a family of nicotinamide adenine dinucleotide phosphate oxidases (Noxs), including the prototypic Nox2-based Nox, and Nox family members: Nox1, Nox4, and Nox5. Critical Issues: Although extensive experimental data support a role for increased ROS levels and altered redox signaling in the pathogenesis of hypertension, the role in clinical hypertension is unclear, as a direct causative role of ROS in blood pressure elevation has yet to be demonstrated in humans. Nevertheless, what is becoming increasingly evident is that abnormal ROS regulation and aberrant signaling through redox-sensitive pathways are important in the pathophysiological processes which is associated with vascular injury and target-organ damage in hypertension. Future Directions: There is a paucity of clinical information related to the mechanisms of oxidative stress and blood pressure elevation, and a few assays accurately measure ROS directly in patients. Such further ROS research is needed in humans and in the development of adequately validated analytical methods to accurately assess oxidative stress in the clinic. Antioxid. Redox Signal. 20, 164–182. PMID:23600794

  13. Reactive oxygen species are related to ionic fluxes and volume decrease in apoptotic cerebellar granule neurons: role of NOX enzymes.

    PubMed

    Hernández-Enríquez, Berenice; Guemez-Gamboa, Alicia; Morán, Julio

    2011-05-01

    Reactive oxygen species (ROS) are produced early during apoptosis of cerebellar granule neurons induced by low potassium (K5) and staurosporine (Sts). In addition, K5 and Sts activate NADPH oxidases (NOX). Recently, we described that K5 and Sts induce apoptotic volume decrease (AVD) at a time when ROS generation and NOX activity occur. In the present study, we evaluated the relationship between ROS generation and ionic fluxes during AVD. Here, we showed that K5- and Sts-induced AVD was inhibited by antioxidants and that direct ROS production induced AVD. Moreover, NOX inhibitors eliminated AVD induced by both K5 and Sts. Sts, but not K5, failed to induce AVD in cerebellar granule neurons from NOX2 knockout mice. These findings suggest that K5- and Sts-induced AVD is largely mediated by ROS produced by NOX. On the other hand, we also found that the blockage of ionic fluxes involved in AVD inhibited both ROS generation and NOX activity. These findings suggest that ROS generation and NOX activity are involved in ionic fluxes activation, which in turn could maintain ROS generation by activating NOX, leading to a self-amplifying cycle.

  14. Novel Nox inhibitor of oxLDL-induced reactive oxygen species formation in human endothelial cells.

    PubMed

    Stielow, Claudia; Catar, Rusan A; Muller, Gregor; Wingler, Kirstin; Scheurer, Peter; Schmidt, Harald H H W; Morawietz, Henning

    2006-05-26

    In this study, we investigated effects of a novel NAD(P)H oxidase (Nox)-inhibitor 3-benzyl-7-(2-benzoxazolyl)thio-1,2,3-triazolo[4,5-d]pyrimidine (VAS2870) on oxidized low-density lipoprotein (oxLDL)-mediated reactive oxygen species (ROS) formation in human endothelial cells. Primary cultures of human umbilical vein endothelial cells were cultured to confluence and ROS formation was induced with 50microg/ml oxLDL for 2h. ROS formation was detected by chemiluminescence (CL) using the Diogenes reagent. OxLDL induced ROS formation in human endothelial cells (171+/-12%; n=10, P<0.05 vs. control). This augmented ROS formation in response to oxLDL was completely inhibited by the Nox inhibitor VAS2870 (101+/-9%; n=7, P<0.05 vs. oxLDL). Similar results were obtained with superoxide dismutase (91+/-7%; n=7, P<0.05 vs. oxLDL). However, the Nox4 mRNA expression level was neither changed by oxLDL nor VAS2870. We conclude that VAS2870 could provide a novel strategy to inhibit the augmented endothelial superoxide anion formation in response to cardiovascular risk factors. PMID:16603125

  15. Modeling Species Inhibition of NO oxidation in Urea-SCR Catalysts for Diesel Engine NOx Control

    SciTech Connect

    Devarakonda, Maruthi N.; Tonkyn, Russell G.; Tran, Diana N.; Lee, Jong H.; Herling, Darrell R.

    2010-09-15

    Urea-selective catalytic reduction (SCR) catalysts are regarded as the leading NOx aftertreatment technology to meet the 2010 NOx emission standards for on-highway vehicles running on heavy-duty diesel engines. However, issues such as low NOx conversion at low temperature conditions still exist due to various factors, including incomplete urea thermolysis, inhibition of SCR reactions by hydrocarbons and H2O. We have observed a noticeable reduction in the standard SCR reaction efficiency at low temperature with increasing water content. We observed a similar effect when hydrocarbons are present in the stream. This effect is absent under fast SCR conditions where NO ~ NO2 in the feed gas. As a first step in understanding the effects of such inhibition on SCR reaction steps, kinetic models that predict the inhibition behavior of H2O and hydrocarbons on NO oxidation are presented in the paper. A one-dimensional SCR model was developed based on conservation of species equations and was coded as a C-language S-function and implemented in Matlab/Simulink environment. NO oxidation and NO2 dissociation kinetics were defined as a function of the respective adsorbate’s storage in the SCR catalyst. The corresponding kinetic models were then validated on temperature ramp tests that showed good match with the test data.

  16. Modeling Species Inhibition of NO Oxidation in Urea-SCR Catalysts for Diesel Engine NOx Control

    SciTech Connect

    Devarakonda, Maruthi N.; Tonkyn, Russell G.; Tran, Diana N.; Lee, Jong H.; Herling, Darrell R.

    2011-04-20

    Urea-selective catalytic reduction (SCR) catalysts are regarded as the leading NOx aftertreatment technology to meet the 2010 NOx emission standards for on-highway vehicles running on heavy-duty diesel engines. However, issues such as low NOx conversion at low temperature conditions still exist due to various factors, including incomplete urea thermolysis, inhibition of SCR reactions by hydrocarbons and H2O. We have observed a noticeable reduction in the standard SCR reaction efficiency at low temperature with increasing water content. We observed a similar effect when hydrocarbons are present in the stream. This effect is absent under fast SCR conditions where NO ~ NO2 in the feed gas. As a first step in understanding the effects of such inhibition on SCR reaction steps, kinetic models that predict the inhibition behavior of H2O and hydrocarbons on NO oxidation are presented in the paper. A one-dimensional SCR model was developed based on conservation of species equations and was coded as a C-language S-function and implemented in Matlab/Simulink environment. NO oxidation and NO2 dissociation kinetics were defined as a function of the respective adsorbate’s storage in the Fe-zeolite SCR catalyst. The corresponding kinetic models were then validated on temperature ramp tests that showed good match with the test data. Such inhibition models will improve the accuracy of model based control design for integrated DPF-SCR aftertreatment systems.

  17. Endoplasmic Reticulum Stress and Nox-Mediated Reactive Oxygen Species Signaling in the Peripheral Vasculature: Potential Role in Hypertension

    PubMed Central

    Nabeebaccus, Adam A.; Shah, Ajay M.; Camargo, Livia L.; Filho, Sidney V.; Lopes, Lucia R.

    2014-01-01

    Abstract Significance: Reactive oxygen species (ROS) are produced during normal endoplasmic reticulum (ER) metabolism. There is accumulating evidence showing that under stress conditions such as ER stress, ROS production is increased via enzymes of the NADPH oxidase (Nox) family, especially via the Nox2 and Nox4 isoforms, which are involved in the regulation of blood pressure. Hypertension is a major contributor to cardiovascular and renal disease, and it has a complex pathophysiology involving the heart, kidney, brain, vessels, and immune system. ER stress activates the unfolded protein response (UPR) signaling pathway that has prosurvival and proapoptotic components. Recent Advances: Here, we summarize the evidence regarding the association of Nox enzymes and ER stress, and its potential contribution in the setting of hypertension, including the role of other conditions that can lead to hypertension (e.g., insulin resistance and diabetes). Critical Issues: A better understanding of this association is currently of great interest, as it will provide further insights into the cellular mechanisms that can drive the ER stress-induced adaptive versus maladaptive pathways linked to hypertension and other cardiovascular conditions. More needs to be learnt about the precise signaling regulation of Nox(es) and ER stress in the cardiovascular system. Future Directions: The development of specific approaches that target individual Nox isoforms and the UPR signaling pathway may be important for the achievement of therapeutic efficacy in hypertension. Antioxid. Redox Signal. 20, 121–134. PMID:23472786

  18. Gaseous Species Measurements of Alternative Jet Fuels in Sooting Laminar Coflow Diffusion Flames

    NASA Astrophysics Data System (ADS)

    Zabeti, Parham

    The gaseous species concentration of Jet A-1, GTL, CTL and a blend of 80 vol.% GTL and 20 vol.% hexanol jet fuels in laminar coflow diffusion flames have been measured and studied. These species are carbon monoxide, carbon dioxide, oxygen, methane, ethane, ethylene, propylene, and acetylene. Benzene and propyne concentrations were also detected in CTL flames. 1-Butene has been quantified for the blend of GTL and hexanol flame. The detailed experimental setup has been described and results from different flames are compared. The CO is produced in a same amount in all the flames. The CTL flame had the largest and GTL/hexanol flame had lowest CO2 concentrations. The results indicate that GTL and GTL hexanol blend flames produce similar concentrations for all the measured hydrocarbon species and have the highest concentration among all the jet fuels. The experimental results from Jet A-1 fuel are also compared with numerical studies by Saffaripour et al .

  19. Effect of gaseous cement industry effluents on four species of microalgae.

    PubMed

    Talec, Amélie; Philistin, Myrvline; Ferey, Frédérique; Walenta, Günther; Irisson, Jean-Olivier; Bernard, Olivier; Sciandra, Antoine

    2013-09-01

    Experiments were performed at lab scale in order to test the possibility to grow microalgae with CO2 from gaseous effluent of cement industry. Four microalgal species (Dunaliella tertiolecta, Chlorella vulgaris, Thalassiosira weissflogii, and Isochrysis galbana), representing four different phyla were grown with CO2 enriched air or with a mixture of gasses mimicking the composition of a typical cement flue gas (CFG). In a second stage, the culture submitted to the CFG received an increasing concentration of dust characteristic of cement industry. Results show that growth for the four species is not affected by the CFG. Dust added at realistic concentrations do not have any impact on growth. For dust concentrations in two ranges of magnitude higher, microalgae growth was inhibited. PMID:23811523

  20. Symbiotic lactobacilli stimulate gut epithelial proliferation via Nox-mediated generation of reactive oxygen species.

    PubMed

    Jones, Rheinallt M; Luo, Liping; Ardita, Courtney S; Richardson, Arena N; Kwon, Young Man; Mercante, Jeffrey W; Alam, Ashfaqul; Gates, Cymone L; Wu, Huixia; Swanson, Phillip A; Lambeth, J David; Denning, Patricia W; Neish, Andrew S

    2013-11-27

    The resident prokaryotic microbiota of the metazoan gut elicits profound effects on the growth and development of the intestine. However, the molecular mechanisms of symbiotic prokaryotic-eukaryotic cross-talk in the gut are largely unknown. It is increasingly recognized that physiologically generated reactive oxygen species (ROS) function as signalling secondary messengers that influence cellular proliferation and differentiation in a variety of biological systems. Here, we report that commensal bacteria, particularly members of the genus Lactobacillus, can stimulate NADPH oxidase 1 (Nox1)-dependent ROS generation and consequent cellular proliferation in intestinal stem cells upon initial ingestion into the murine or Drosophila intestine. Our data identify and highlight a highly conserved mechanism that symbiotic microorganisms utilize in eukaryotic growth and development. Additionally, the work suggests that specific redox-mediated functions may be assigned to specific bacterial taxa and may contribute to the identification of microbes with probiotic potential.

  1. Symbiotic lactobacilli stimulate gut epithelial proliferation via Nox-mediated generation of reactive oxygen species

    PubMed Central

    Jones, Rheinallt M; Luo, Liping; Ardita, Courtney S; Richardson, Arena N; Kwon, Young Man; Mercante, Jeffrey W; Alam, Ashfaqul; Gates, Cymone L; Wu, Huixia; Swanson, Phillip A; Lambeth, J David; Denning, Patricia W; Neish, Andrew S

    2013-01-01

    The resident prokaryotic microbiota of the metazoan gut elicits profound effects on the growth and development of the intestine. However, the molecular mechanisms of symbiotic prokaryotic–eukaryotic cross-talk in the gut are largely unknown. It is increasingly recognized that physiologically generated reactive oxygen species (ROS) function as signalling secondary messengers that influence cellular proliferation and differentiation in a variety of biological systems. Here, we report that commensal bacteria, particularly members of the genus Lactobacillus, can stimulate NADPH oxidase 1 (Nox1)-dependent ROS generation and consequent cellular proliferation in intestinal stem cells upon initial ingestion into the murine or Drosophila intestine. Our data identify and highlight a highly conserved mechanism that symbiotic microorganisms utilize in eukaryotic growth and development. Additionally, the work suggests that specific redox-mediated functions may be assigned to specific bacterial taxa and may contribute to the identification of microbes with probiotic potential. PMID:24141879

  2. Remote Measurement of Pollution - A 40-Year Langley Retrospective. Part 1; Temperature and Gaseous Species

    NASA Technical Reports Server (NTRS)

    Remsberg, Ellis E.

    2011-01-01

    The National Aeronautics and Space Administration (NASA) phased down its Apollo Moon Program after 1970 in favor of a partly reusable Space Shuttle vehicle that could be used to construct and supply a manned, Earth-orbiting Space Station. Applications programs were emphasized in response to the growing public concern about Earth's finite natural resources and the degradation of its environment. Shortly thereafter, a workshop was convened in Norfolk, Virginia, on Remote Measurement of Pollution (or RMOP), and its findings are in a NASA Special Publication (NASA SP-285). The three primary workshop panels and their chairmen were focused on trace gas species (Will Kellogg), atmospheric particulates or aerosols (Verner Suomi), and water pollution (Gifford Ewing). Many of the workshop participants were specialists in the techniques that might be employed for the regional to global-scale, remote measurements from an Earth-orbiting satellite. The findings and recommendations of the RMOP Report represent the genesis of and a blueprint for the satellite, atmospheric sensing programs within NASA for nearly two decades. This paper is a brief, 40-year retrospective of those instrument developments that were an outgrowth of the RMOP activity. Its focus is on satellite measurement capabilities for temperature and gaseous species that were demonstrated by atmospheric technologists at the Langley Research Center. Limb absorption by solar occultation, limb infrared radiometry, and gas filter correlation radiometry techniques provided significant science data, so they are emphasized in this review.

  3. Alliin Attenuated RANKL-Induced Osteoclastogenesis by Scavenging Reactive Oxygen Species through Inhibiting Nox1

    PubMed Central

    Chen, Yueqi; Sun, Jingjing; Dou, Ce; Li, Nan; Kang, Fei; Wang, Yuan; Cao, Zhen; Yang, Xiaochao; Dong, Shiwu

    2016-01-01

    The healthy skeleton requires a perfect coordination of the formation and degradation of bone. Metabolic bone disease like osteoporosis is resulted from the imbalance of bone formation and/or bone resorption. Osteoporosis also reflects lower level of bone matrix, which is contributed by up-regulated osteoclast-mediated bone resorption. It is reported that monocytes/macrophage progenitor cells or either hematopoietic stem cells (HSCs) gave rise to multinucleated osteoclasts. Thus, inhibition of osteoclastic bone resorption generally seems to be a predominant therapy for treating osteoporosis. Recently, more and more natural compounds have been discovered, which have the ability of inhibiting osteoclast differentiation and fusion. Alliin (S-allyl-l-cysteine sulfoxides, SACSO) is the major component of aged garlic extract (AGE), bearing broad-spectrum natural antioxidant properties. However, its effects on bone health have not yet been explored. Hence, we designed the current study to explore its effects and role in receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast fusion and differentiation. It was revealed that alliin had an inhibitory effect in osteoclasteogenesis with a dose-dependent manner via blocking the c-Fos-NFATc1 signaling pathway. In addition, alliin decreased the generation of reactive oxygen species (ROS) and down-regulated the expression of NADPH oxidase 1 (Nox1). The overall results revealed that alliin could be a potential therapeutic agent in the treatment of osteoporosis. PMID:27657047

  4. [Effects of gaseous compositions the on simultaneous removal of NO(x) and SO2 from simulated flue gas by ammonia absorption].

    PubMed

    Wang, Hong; Zhu, Tian-Le; Wang, Mei-Yan

    2013-01-01

    The effects of NO(x) oxidation ratio, O2 and SO2 concentrations in simulated flue gas as well as addition of S(IV) oxidation inhibitor NaS2O3 on the simultaneous removal of SO2 and NO(x) by ammonia absorption were investigated under the conditions of pH 5.9-6.1 and aqueous S(IV) concentration > or = 1.0 mol x L(-1). The research results showed that NO2 could be effectively absorbed by ammonium sulfite, but the NO absorption was negligible. Therefore, NO oxidation is the premise of NO(x) removal. Aqueous S(IV) concentration is a key factor affecting NO2 absorption removal, the higher the O2 concentration or the lower the SO2 concentration, the faster the aaqueous S(IV) concentration decreased, which resulted in a faster decrease of NO2 removal efficiency. S(IV) oxidation was inhibited to some extent by the addition of oxidation inhibitor S2O3(2-) into the absorption solution. As a result, the decrease of NO2 removal efficiency became slower.

  5. Binding of EBP50 to Nox organizing subunit p47phox is pivotal to cellular reactive species generation and altered vascular phenotype.

    PubMed

    Al Ghouleh, Imad; Meijles, Daniel N; Mutchler, Stephanie; Zhang, Qiangmin; Sahoo, Sanghamitra; Gorelova, Anastasia; Henrich Amaral, Jefferson; Rodríguez, Andrés I; Mamonova, Tatyana; Song, Gyun Jee; Bisello, Alessandro; Friedman, Peter A; Cifuentes-Pagano, M Eugenia; Pagano, Patrick J

    2016-09-01

    Despite numerous reports implicating NADPH oxidases (Nox) in the pathogenesis of many diseases, precise regulation of this family of professional reactive oxygen species (ROS) producers remains unclear. A unique member of this family, Nox1 oxidase, functions as either a canonical or hybrid system using Nox organizing subunit 1 (NoxO1) or p47(phox), respectively, the latter of which is functional in vascular smooth muscle cells (VSMC). In this manuscript, we identify critical requirement of ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50; aka NHERF1) for Nox1 activation and downstream responses. Superoxide (O2 (•-)) production induced by angiotensin II (AngII) was absent in mouse EBP50 KO VSMC vs. WT. Moreover, ex vivo incubation of aortas with AngII showed a significant increase in O2 (•-) in WT but not EBP50 or Nox1 nulls. Similarly, lipopolysaccharide (LPS)-induced oxidative stress was attenuated in femoral arteries from EBP50 KO vs. WT. In silico analyses confirmed by confocal microscopy, immunoprecipitation, proximity ligation assay, FRET, and gain-/loss-of-function mutagenesis revealed binding of EBP50, via its PDZ domains, to a specific motif in p47(phox) Functional studies revealed AngII-induced hypertrophy was absent in EBP50 KOs, and in VSMC overexpressing EBP50, Nox1 gene silencing abolished VSMC hypertrophy. Finally, ex vivo measurement of lumen diameter in mouse resistance arteries exhibited attenuated AngII-induced vasoconstriction in EBP50 KO vs. WT. Taken together, our data identify EBP50 as a previously unidentified regulator of Nox1 and support that it promotes Nox1 activity by binding p47(phox) This interaction is pivotal for agonist-induced smooth muscle ROS, hypertrophy, and vasoconstriction and has implications for ROS-mediated physiological and pathophysiological processes.

  6. Binding of EBP50 to Nox organizing subunit p47phox is pivotal to cellular reactive species generation and altered vascular phenotype.

    PubMed

    Al Ghouleh, Imad; Meijles, Daniel N; Mutchler, Stephanie; Zhang, Qiangmin; Sahoo, Sanghamitra; Gorelova, Anastasia; Henrich Amaral, Jefferson; Rodríguez, Andrés I; Mamonova, Tatyana; Song, Gyun Jee; Bisello, Alessandro; Friedman, Peter A; Cifuentes-Pagano, M Eugenia; Pagano, Patrick J

    2016-09-01

    Despite numerous reports implicating NADPH oxidases (Nox) in the pathogenesis of many diseases, precise regulation of this family of professional reactive oxygen species (ROS) producers remains unclear. A unique member of this family, Nox1 oxidase, functions as either a canonical or hybrid system using Nox organizing subunit 1 (NoxO1) or p47(phox), respectively, the latter of which is functional in vascular smooth muscle cells (VSMC). In this manuscript, we identify critical requirement of ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50; aka NHERF1) for Nox1 activation and downstream responses. Superoxide (O2 (•-)) production induced by angiotensin II (AngII) was absent in mouse EBP50 KO VSMC vs. WT. Moreover, ex vivo incubation of aortas with AngII showed a significant increase in O2 (•-) in WT but not EBP50 or Nox1 nulls. Similarly, lipopolysaccharide (LPS)-induced oxidative stress was attenuated in femoral arteries from EBP50 KO vs. WT. In silico analyses confirmed by confocal microscopy, immunoprecipitation, proximity ligation assay, FRET, and gain-/loss-of-function mutagenesis revealed binding of EBP50, via its PDZ domains, to a specific motif in p47(phox) Functional studies revealed AngII-induced hypertrophy was absent in EBP50 KOs, and in VSMC overexpressing EBP50, Nox1 gene silencing abolished VSMC hypertrophy. Finally, ex vivo measurement of lumen diameter in mouse resistance arteries exhibited attenuated AngII-induced vasoconstriction in EBP50 KO vs. WT. Taken together, our data identify EBP50 as a previously unidentified regulator of Nox1 and support that it promotes Nox1 activity by binding p47(phox) This interaction is pivotal for agonist-induced smooth muscle ROS, hypertrophy, and vasoconstriction and has implications for ROS-mediated physiological and pathophysiological processes. PMID:27540115

  7. Nox and renal disease.

    PubMed

    Holterman, Chet E; Read, Naomi C; Kennedy, Chris R J

    2015-04-01

    Since the first demonstration of Nox enzyme expression in the kidney in the early 1990s and the subsequent identification of Nox4, or RENOX, a decade later, it has become apparent that the Nox family of reactive oxygen species (ROS) generating enzymes plays an integral role in the normal physiological function of the kidney. As our knowledge of Nox expression patterns and functions in various structures and specialized cell types within the kidney grows, so does the realization that Nox-derived oxidative stress contributes significantly to a wide variety of renal pathologies through their ability to modify lipids and proteins, damage DNA and activate transcriptional programmes. Diverse studies demonstrate key roles for Nox-derived ROS in kidney fibrosis, particularly in settings of chronic renal disease such as diabetic nephropathy. As the most abundant Nox family member in the kidney, much emphasis has been placed on the role of Nox4 in this setting. However, an ever growing body of work continues to uncover key roles for other Nox family members, not only in diabetic kidney disease, but in a diverse array of renal pathological conditions. The objective of the present review is to highlight the latest novel developments in renal Nox biology with an emphasis not only on diabetic nephropathy but many of the other renal disease contexts where oxidative stress is implicated.

  8. NOX1-induced accumulation of reactive oxygen species in abdominal fat-derived mesenchymal stromal cells impinges on long-term proliferation.

    PubMed

    Sela, M; Tirza, G; Ravid, O; Volovitz, I; Solodeev, I; Friedman, O; Zipori, D; Gur, E; Krelin, Y; Shani, N

    2015-04-16

    Mesenchymal stromal cells (MSCs) are multipotent and can be derived from different adult tissues including fat. Our repeated attempts to produce long-term proliferative cultures of rat abdominal adipose stem cells (aASCs) under normal oxygen concentration (21%) were unsuccessful. We set to examine the events controlling this cytostasis of aASCs and found that it resulted from overproduction of reactive oxygen species (ROS) that led to apoptosis. ROS overproduction in aASCs was accompanied by increased expression of NOX1 but not of NOX2 or NOX4. NOX family members are an important source of intracellular ROS pointing to NOX1 involvement in ROS accumulation. This was verified when aASCs that were grown under 3% oxygen conditions expanded long term, displaying reduced NOX1 expression and decreased ROS accumulation. NOX1 involvement in aASC cytostasis was reaffirmed when cells that were expanded under normoxic conditions in the presence of a specific NOX1 inhibitor, ML171, demonstrated reduced ROS accumulation, reduced apoptosis and long-term expansion. aASC expansion arrest was accompanied also by a weak fat differentiation and migratory potential, which was enhanced by NOX1 inhibition. This suggests an inhibitory role for NOX1-induced ROS overproduction on aASCs, their fat differentiation and migratory potential. In contrast to aASCs, similar cells produced from subcutaneous fat were easily expanded in normoxic cultures, exhibiting low ROS concentrations, a low number of apoptotic cells and improved fat differentiation and migration. Taken together, our results show, for the first time, that NOX1-induced ROS accumulation halts ASC expansion and reduces their differentiation and migratory potential under normoxic conditions. Importantly, this phenotype comprises a tissue-specific signature as it was evident in aASCs but not in subcutaneous ASCs. NOX-induced ROS accumulation and cytokine production by fat are part of the metabolic syndrome. The similarity of this

  9. Bone morphogenic protein 4 produced in endothelial cells by oscillatory shear stress induces monocyte adhesion by stimulating reactive oxygen species production from a nox1-based NADPH oxidase.

    PubMed

    Sorescu, George P; Song, Hannah; Tressel, Sarah L; Hwang, Jinah; Dikalov, Sergey; Smith, Debra A; Boyd, Nolan L; Platt, Manu O; Lassègue, Bernard; Griendling, Kathy K; Jo, Hanjoong

    2004-10-15

    Atherosclerosis is an inflammatory disease occurring preferentially in arterial regions exposed to disturbed flow conditions including oscillatory shear stress (OS). OS exposure induces endothelial expression of bone morphogenic protein 4 (BMP4), which in turn may activate intercellular adhesion molecule-1 (ICAM-1) expression and monocyte adhesion. OS is also known to induce monocyte adhesion by producing reactive oxygen species (ROS) from reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, raising the possibility that BMP4 may stimulate the inflammatory response by ROS-dependent mechanisms. Here we show that ROS scavengers blocked ICAM-1 expression and monocyte adhesion induced by BMP4 or OS in endothelial cells (ECs). Similar to OS, BMP4 stimulated H2O2 and O2- production in ECs. Next, we used ECs obtained from p47phox-/- mice (MAE-p47-/-), which do not produce ROS in response to OS, to determine the role of NADPH oxidases. Similar to OS, BMP4 failed to induce monocyte adhesion in MAE-p47-/-, but it was restored when the cells were transfected with p47phox plasmid. Moreover, OS-induced O2- production was blocked by noggin (a BMP antagonist), suggesting a role for BMP. Furthermore, OS increased gp91phox (nox2) and nox1 mRNA levels while decreasing nox4. In contrast, BMP4 induced nox1 mRNA expression, whereas nox2 and nox4 were decreased or not affected, respectively. Also, OS-induced monocyte adhesion was blocked by knocking down nox1 with the small interfering RNA (siRNA). Finally, BMP4 siRNA inhibited OS-induced ROS production and monocyte adhesion. Together, these results suggest that BMP4 produced in ECs by OS stimulates ROS release from the nox1-dependent NADPH oxidase leading to inflammation, a critical early atherogenic step. PMID:15388638

  10. Efficiency of different respiratory protective devices for removal of particulate and gaseous reactive oxygen species from welding fumes.

    PubMed

    Chen, Hsiu-Ling; Chung, Shih-Hsiang; Jhuo, Ming-Lin

    2013-01-01

    Ultraviolet (UV) light inherent to welding processes generates ozone (O(3)) with subsequent formation of reactive oxygen species (ROS) through photochemical reactions when UV light is present with O(3). This study aimed to determine the performance of filters used as respiratory protective devices by welding personnel to simultaneously mitigate particulate and gaseous inhalation hazards. Four respiratory protective devices were selected for this study, including a surgical facemask, a cotton-fabric facemask, an activated-carbon facemask, and an N95 respirator. The removal efficiencies for the particulates in welding fumes were all above 98%. For particulate-phase ROS, the removal efficiencies of the different respiratory protective devices ranged from 83.5% to 94.1%; however, the removal efficiencies for gaseous ROS were only 1.3% (active carbon facemask) to 21.1% (N95 respirator). The data indicated that the respiratory protective devices commercially available cannot block the passage of the gas-phase ROS found in welding fumes. PMID:23428060

  11. Efficiency of different respiratory protective devices for removal of particulate and gaseous reactive oxygen species from welding fumes.

    PubMed

    Chen, Hsiu-Ling; Chung, Shih-Hsiang; Jhuo, Ming-Lin

    2013-01-01

    Ultraviolet (UV) light inherent to welding processes generates ozone (O(3)) with subsequent formation of reactive oxygen species (ROS) through photochemical reactions when UV light is present with O(3). This study aimed to determine the performance of filters used as respiratory protective devices by welding personnel to simultaneously mitigate particulate and gaseous inhalation hazards. Four respiratory protective devices were selected for this study, including a surgical facemask, a cotton-fabric facemask, an activated-carbon facemask, and an N95 respirator. The removal efficiencies for the particulates in welding fumes were all above 98%. For particulate-phase ROS, the removal efficiencies of the different respiratory protective devices ranged from 83.5% to 94.1%; however, the removal efficiencies for gaseous ROS were only 1.3% (active carbon facemask) to 21.1% (N95 respirator). The data indicated that the respiratory protective devices commercially available cannot block the passage of the gas-phase ROS found in welding fumes.

  12. Partitioning of metal species during an enriched fuel combustion experiment. speciation in the gaseous and particulate phases.

    PubMed

    Pavageau, Marie-Pierre; Morin, Anne; Seby, Fabienne; Guimon, Claude; Krupp, Eva; Pécheyran, Christophe; Poulleau, Jean; Donard, Olivier F X

    2004-04-01

    Combustion processes are the most important source of metal in the atmosphere and need to be better understood to improve flue gas treatment and health impact studies. This combustion experiment was designed to study metal partitioning and metal speciation in the gaseous and particulate phases. A light fuel oil was enriched with 15 organometallic compounds of the following elements: Pb, Hg, As, Cu, Zn, Cd, Se, Sn, Mn, V, Tl, Ni, Co, Cr, and Sb. The resulting mixture was burnt in a pilot-scale fuel combustion boiler under controlled conditions. After filtration of the particles, the gaseous species were sampled in the stack through a heated sampling tube simultaneously by standardized washing bottles-based sampling techniques and cryogenically. The cryogenic samples were collected at -80 degrees C for further speciation analysis by LT/GC-ICPMS. Three species of selenium and two of mercury were evidenced as volatile species in the flue gas. Thermodynamic predictions and experiments suggest the following volatile metal species to be present in the flue gas: H2Se, CSSe, CSe2, SeCl2, Hg(0), and HgCl2. Quantification of volatile metal species in comparison between cryogenic techniques and the washing bottles-based sampling method is also discussed. Concerning metal partitioning, the results indicated that under these conditions, at least 60% (by weight) of the elements Pb, Sn, Cu, Co, Tl, Mn, V, Cr, Ni, Zn, Cd, and Sb mixed to the fuel were found in the particulate matter. For As and Se, 37 and 17%, respectively, were detected in the particles, and no particulate mercury was found. Direct metal speciation in particles was performed by XPS allowing the determination of the oxidation state of the following elements: Sb(V), Tl(III), Mn(IV), Cd(II), Zn(II), Cr(III), Ni(II), Co(II), V(V), and Cu(II). Water soluble species of inorganic Cr, As, and Se in particulate matter were determined by HPLC/ICP-MS and identified in the oxidation state Cr(III), As(V), and Se(IV).

  13. Angiotensin II induces Fat1 expression/activation and vascular smooth muscle cell migration via Nox1-dependent reactive oxygen species generation

    PubMed Central

    Bruder-Nascimento, T; Chinnasamy, P; Riascos-Bernal, DF; Cau, SB; Callera, GE; Touyz, RM; Tostes, RC; Sibinga, NES

    2013-01-01

    Fat1 is an atypical cadherin that controls vascular smooth muscle cell (VSMC) proliferation and migration. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 (Nox1) is an important source of reactive oxygen species (ROS) in VSMCs. Angiotensin II (Ang II) induces the expression and/or activation of both Fat1 and Nox1 proteins. This study tested the hypothesis that Ang II-induced Fat1 activation and VSMC migration are mediated by Nox1-dependent ROS generation and redox signaling. Studies were performed in cultured VSMCs from Sprague-Dawley rats. Cells were treated with Ang II (1 μmol/L) for short (5 to 30 min) or long term stimulations (3 to 12 h) in the absence or presence of the antioxidant apocynin (10 μmol/L), extracellular-signal-regulated kinases 1/2 (Erk1/2) inhibitor PD98059 (1 μmol/L), or Ang II type 1 receptor (AT1R) valsartan (1 μmol/L). siRNA was used to knockdown Nox1 or Fat1. Cell migration was determined by Boyden chamber assay. Ang II increased Fat1 mRNA and protein levels and promoted Fat1 translocation to the cell membrane, responses that were inhibited by AT1R antagonist and antioxidant treatment. Downregulation of Nox1 inhibited the effects of Ang II on Fat1 protein expression. Nox1 protein induction, ROS generation, and p44/p42 MAPK phosphorylation in response to Ang II were prevented by valsartan and apocynin, and Nox1 siRNA inhibited Ang II-induced ROS generation. Knockdown of Fat1 did not affect Ang II-mediated increases in Nox1 expression or ROS. Inhibition of p44/p42 MAPK phosphorylation by PD98059 abrogated the Ang II-induced increase in Fat1 expression and membrane translocation. Knockdown of Fat1 inhibited Ang II-induced VSMC migration, which was also prevented by valsartan, apocynin, PD98059, and Nox1 siRNA. Our findings indicate that Ang II regulates Fat1 expression and activity and induces Fat1-dependent VSMC migration via activation of AT1R, ERK1/2, and Nox1-derived ROS, suggesting a role for Fat1 downstream of Ang II

  14. 3D-printed system optimizing dissolution of hyperpolarized gaseous species for micro-sized NMR.

    PubMed

    Causier, A; Carret, G; Boutin, C; Berthelot, T; Berthault, P

    2015-05-01

    Dissolution of hyperpolarized species in liquids of interest for NMR is often hampered by the presence of bubbles that degrade the field homogeneity. Here a device composed of a bubble pump and a miniaturized NMR cell both fitted inside the narrow bore of an NMR magnet is built by 3D printing. (129)Xe NMR experiments performed with hyperpolarized xenon reveal high and homogeneous dissolution of the gas in water.

  15. CARS (coherent anti-Stokes Raman spectroscopy) detection of gaseous species for diamond deposition process

    SciTech Connect

    Roman, W.C.; Eckbreth, A.C. )

    1989-01-01

    In order to understand the complicated chemical and physical processes that occur during the deposition of hard face coatings such as diamond, diagnostics that are remote, nonintrusive and sensitive to potential chemical species are necessary. One particularly promising approach is coherent anti-Stokes Raman spectroscopy (CARS) useful for measurements of temperature and species concentrations. Results to be described will include CARS measurements on a PACVD reactor used for depositing high quality diamond films. A mixture of acetylene (C{sub 2}H{sub 2}) and Argon, tested over a range of total pressures down to 0.1 Torr, was used to calibrate the CARS system. With the existing CARS system, detectivity of C{sub 2}H{sub 2} to 5 mtorr was demonstrated. This paper describes details of the scanned narrowband colinear CARS system and examples of CARS spectra obtained for CH{sub 4} and C{sub 2}H{sub 2} species under rf PACVD diamond deposition conditions and also using an alternate filament assisted technique.

  16. Source identification and trends in concentrations of gaseous and fine particulate principal species in Seoul, South Korea.

    PubMed

    Kang, Choong-Min; Kang, Byung-Wook; Lee, Hak Sung

    2006-07-01

    Ambient measurements were made using two sets of annular denuder system during the four seasons (April 2001 to February 2002) and were then compared with the results during the period of 1996-1997 to estimate the trends and seasonal variations in concentrations of gaseous and fine particulate matter (PM2.5) principal species. Annual averages of gaseous HNO3 and NH3 increased by 11% and 6%, respectively, compared with those of the previous study, whereas HONO and SO2 decreased by 11% and 136%, respectively. The PM2.5 concentration decreased by -17%, 35% for SO4(2-), and 29% for NH4+, whereas NO3- increased by 21%. Organic carbon (OC) and elemental carbon (EC) were 12.8 and 5.98 microg/m(-3), accounting for -26 and 12% of PM2.5 concentration, respectively. The species studied accounted for 84% of PM2.5 concentration, ranging from 76% in winter to 97% in summer. Potential source contribution function (PSCF) analysis was used to identify possible source areas affecting air pollution levels at a receptor site in Seoul. High possible source areas in concentrations of PM2.5, NO3-, SO4(2-), NH4+, and K+ were coastal cities of Liaoning province (possibly emissions from oil-fired boilers on ocean liners and fishing vessels and industrial emissions), inland areas of Heibei/Shandong provinces (the highest density areas of agricultural production and population) in China, and typical port cities (Mokpo, Yeosu, and Busan) of South Korea. In the PSCF map for OC, high possible source areas were also coastal cities of Liaoning province and inland areas of Heibei/Shandong provinces in China. In contrast, high possible source areas of EC were highlighted in the south of the Yellow Sea, indicating possible emissions from oil-fired boilers on large ships between South Korea and Southeast Asia. In summary, the PSCF results may suggest that air pollution levels in Seoul are affected considerably by long-range transport from external areas, such as the coastal zone in China and other

  17. Characterization of gaseous species in scanning atmospheric rf plasma with transmission infrared spectroscopy

    SciTech Connect

    Kim, Seong H.; Kim, Jeong Hoon; Kang, Bang-Kwon

    2008-01-15

    A scanning atmospheric radio-frequency (rf) plasma was analyzed with transmission infrared (IR) spectroscopy. The IR analyses were made for the plasmas used for hydrophobic coating deposition and superhydrophobic coating deposition processes. Since the rf plasma was generated in a small open space with a high gas flow rate in ambient air, the density of gas-phase molecules was very high and the plasma-generated reactive species seemed to undergo various reactions in the gas phase. So, the transmission IR spectra of the scanning atmospheric rf plasma were dominated by gas-phase reaction products, rather than plasma-generated intermediate species. In the CH{sub 4}/He plasma used for hydrophobic coating deposition, C{sub 2}H{sub 6}, C{sub 2}H{sub 2}, and a small amount of C{sub 2}H{sub 4} as well as CO were detected in transmission IR. The intensities of these peaks increased as the rf power increased. The CO formation is due to the activation of oxygen and water in the air. In the CF{sub 4}/H{sub 2}/He plasma used for deposition of superhydrophobic coatings, C{sub 2}F{sub 6}, CF{sub 3}H, COF{sub 2}, and HF were mainly detected. When the H{sub 2}/CF{sub 4} ratio was {approx}0.5, the consumption of CF{sub 4} was the highest. As the H{sub 2}/CF{sub 4} ratio increased higher, the C{sub 2}F{sub 6} production was suppressed while the CF{sub 3}H peak grew and the formation of CH{sub 4} were detected. In both CH{sub 4}/He and CF{sub 4}/H{sub 2}/He plasma systems, the undissociated feed gas molecules seem to be highly excited vibrationally and rotationally. The information on plasma-generated reactive species and their reactions was deduced from the distribution of these gas-phase reaction products.

  18. Determination of Reactive Nitrogen Species (NOx, NOy-HNO3, Peroxyacetyl Nitrates, Total Organic Nitrates) During the PROPHET Summer 2008 Intensive

    NASA Astrophysics Data System (ADS)

    Alaghmand, M.; Slade, N. J.; Mielke, L.; Starn, T.; Carroll, M.; Bertman, S. B.; Stevens, P. S.; Shepson, P. B.

    2008-12-01

    Determinations of NOx, NOy-HNO3, peroxyacetyl nitrates (PANs) and total organic nitrates (∑RONO2) were made during the summer 2008 intensive of the Program for Research on Oxidants: Photochemistry, Emissions and Transport (PROPHET). The Total Reactive Nitrogen Instrument (TRENI), a high sensitivity instrument, is capable of speciating atmospheric nitrogen species. TRENI, a chemiluminescence analyzer with two inlet systems (photolytic cell and heated gold tube) was employed to quantify NO, NO2 and NOy. Another inlet system comprised of thermal dissociation reactors, was employed to speciate NOy components into NOx, PANs and ∑RONO2. The detection limit of TRENI is 5 ppt for NOx and NOy and 20 ppt for total organic nitrates and PANs. In this study, we examine the extent to which we can explain the ∑RONO2 concentrations with known precursors and/or individual RONO2 measurement data. The observed fraction of NOy attributable to the ∑RONO2 is much higher than from previous individual RONO2 measurements. It seems clear that there is a large component of 'missing NOy' in the ∑RONO2 channel, as observed by others using the thermal dissociation inlet approach. We also examine here the potential sources of the frequently observed morning pulse of NOx, and the potential role of the forest canopy in mediating nitrogen chemistry.

  19. Direct Numerical Simulation of Transitional Multicomponent-Species Gaseous and Multicomponent-Liquid Drop-Laden Mixing

    NASA Technical Reports Server (NTRS)

    Selle, Laurent C.; Bellan, Josette

    2006-01-01

    A model of multicomponent-liquid (MC-liquid) drop evaporation in a three-dimensional mixing layer is here exercised at larger Reynolds numbers than in a previous study, and transitional states are obtained. The gas phase is followed in an Eulerian frame and the multitude of drops is described in a Lagrangian frame. Complete coupling between phases is included with source terms in the gas conservation equations accounting for the drop/flow interaction in terms of drop drag, drop heating and species evaporation. The liquid composition, initially specified as a single-Gamma (SG) probability distribution function (PDF) depending on the molar mass is allowed to evolve into a linear combination of two SGPDFs, called the double-Gamma PDF (DGPDF). The compositions of liquid and vapor emanating from the drops are calculated through four moments of the DGPDFs, which are drop-specific and location-specific, respectively. The mixing layer is initially excited to promote the double pairing of its four initial spanwise vortices into an ultimate vortex in which small scales proliferate. Simulations are performed for four liquids of different compositions and the effect of the initial mass loading and initial free-stream gas temperature are explored. For reference, Simulations are also performed for gaseous multicomponent mixing layers for which the effect of Reynolds number is investigated. The results encompass examination of the global layer characteristics, flow visualizations and homogeneous-plane statistics at transition. Comparisons are performed with previous pre-transitional MC-liquid simulations and with transitional single-component (SC) liquid studies. It is found that MCC flows at transition, the classical energy cascade is of similar strength, but that the smallest scales contain orders of magnitude less energy than SC flows, which is confirmed by the larger viscous dissipation in the former case. Contrasting to pre-transitional MC flows, the vorticity and drop

  20. Macrophages generate reactive oxygen species in response to minimally oxidized LDL: TLR4- and Syk-dependent activation of Nox2

    PubMed Central

    Bae, Yun Soo; Lee, Jee Hyun; Choi, Soo Ho; Kim, Sunah; Almazan, Felicidad; Witztum, Joseph L.; Miller, Yury I.

    2009-01-01

    Oxidative modification of low-density lipoprotein (LDL) plays a causative role in the development of atherosclerosis. In this study, we demonstrate that minimally oxidized LDL (mmLDL) stimulates intracellular reactive oxygen species (ROS) generation in macrophages through NADPH oxidase 2 (gp91phox/Nox2), which in turn induces production of RANTES and migration of smooth muscle cells. Peritoneal macrophages from gp91phox/Nox2−/− mice or J774 macrophages in which Nox2 was knocked down by siRNA failed to generate ROS in response to mmLDL. Because mmLDL-induced cytoskeletal changes were dependent on TLR4, we analyzed ROS generation in peritoneal macrophages from wild type, TLR4−/−, or MyD88−/− mice and found that mmLDL-mediated ROS was generated in a TLR4-dependent, but MyD88-independent manner. Furthermore, we found that ROS generation required the recruitment and activation of spleen tyrosine kinase (Syk) and that mmLDL also induced PLCγ1 phosphorylation and PKC membrane translocation. Importantly, the PLCγ1 phosphorylation was reduced in J774 cells expressing Syk-specific shRNA. Nox2 modulated mmLDL activation of macrophages by regulating the expression of proinflammatory cytokines IL-1β, IL-6 and RANTES. We showed that purified RANTES was able to stimulate migration of mouse aortic smooth muscle cells (MASMC) and addition of neutralizing antibody against RANTES abolished the migration of MASMC stimulated by mmLDL-stimulated macrophages. These results suggest that mmLDL induces generation of ROS through sequential activation of TLR4, Syk, PLCγ1, PKC, and gp91phox/Nox2 and thereby stimulates expression of proinflammatory cytokines. These data help explain mechanisms by which endogenous ligands, such as mmLDL, can induce TLR4-dependent, proatherogenic activation of macrophages. PMID:19096031

  1. 40 CFR 90.418 - Data evaluation for gaseous emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... gaseous emissions recording, record the last two minutes of each mode and determine the average values for HC, CO, CO2 and NOX during each mode from the average concentration readings determined from...

  2. Climate sensitivity of gaseous elemental mercury dry deposition to plants: impacts of temperature, light intensity, and plant species.

    PubMed

    Rutter, Andrew P; Schauer, James J; Shafer, Martin M; Creswell, Joel; Olson, Michael R; Clary, Alois; Robinson, Michael; Parman, Andrew M; Katzman, Tanya L

    2011-01-15

    Foliar accumulations of gaseous elemental mercury (GEM) were measured in three plant species between nominal temperatures of 10 and 30 °C and nominal irradiances of 0, 80, and 170 W m(-2) (300 nm-700 nm) in a 19 m(3) controlled environment chamber. The plants exposed were as follows: White Ash (Fraxinus americana; WA); White Spruce (Picea glauca; WS); and Kentucky Bluegrass (Poa partensis; KYBG). Foliar enrichments in the mercury stable isotope ((198)Hg) were used to measure mercury accumulation. Exposures lasted for 1 day after which the leaves were digested in hot acid and the extracted mercury was analyzed with ICPMS. Resistances to accumulative uptake by leaves were observed to be dependent on both light and temperature, reaching minima at optimal growing conditions (20 °C; 170 W m(-2) irradiance between 300-700 nm). Resistances typically increased at lower (10 °C) and higher (30 °C) temperatures and decreased with higher intensities of irradiance. Published models were modified and used to interpret the trends in stomatal and leaf interior resistances to GEM observed in WA. The model captured the experimental trends well and revealed that stomatal and internal resistances were both important across much of the temperature range. At high temperatures, however, stomatal resistance dominated due to increased water vapor pressure deficits. The resistances measured in this study were used to model foliar accumulations of GEM at a northern US deciduous forest using atmospheric mercury and climate measurements made over the 2003 growing season. The results were compared to modeled accumulations for GEM, RGM, and PHg using published deposition velocities. Predictions of foliar GEM accumulation were observed to be a factor of 5-10 lower when the temperature and irradiance dependent resistances determined in this study were used in place of previously published data. GEM uptake by leaves over the growing season was shown to be an important deposition pathway (2

  3. NADPH oxidase NOX2 defines a new antagonistic role for reactive oxygen species and cAMP/PKA in the regulation of insulin secretion.

    PubMed

    Li, Ning; Li, Bin; Brun, Thierry; Deffert-Delbouille, Christine; Mahiout, Zahia; Daali, Youssef; Ma, Xiao-Juan; Krause, Karl-Heinz; Maechler, Pierre

    2012-11-01

    In insulin-secreting cells, expression of NADPH oxidase (NOX), a potent source of ROS, has been reported, along with controversial findings regarding its function. Here, the role of NOXs was investigated: first by expression and cellular localization in mouse and human pancreatic islets, and then by functional studies in islets isolated from Nox isoform-specific knockout mice. Both human and mouse β-cells express NOX, in particular NOX2. With use of Nox isoform-specific knockout mice, functional analysis revealed Nox2 as the predominant isoform. In human islets, NOX2 colocalized with both insulin granules and endosome/lysosome membranes. Nox2-deficient islets stimulated with 22.8 mmol/L glucose exhibited potentiation of insulin release compared with controls, an effect confirmed with in vitro knockdown of Nox2. The enhanced secretory function in Nox2-deficient islets was associated with both lower superoxide levels and elevated cAMP concentrations. In control islets, GLP-1 and other cAMP inducers suppressed glucose-induced ROS production similarly to Nox2 deficiency. Inhibiting cAMP-dependent protein kinase reduced the secretory response in Nox2-null islets, although not in control islets. This study ascribes a new role for NOX2 in pancreatic β-cells as negative modulator of the secretory response, reducing cAMP/PKA signaling secondary to ROS generation. Results also show reciprocal inhibition between the cAMP/PKA pathway and ROS.

  4. NADPH Oxidase NOX2 Defines a New Antagonistic Role for Reactive Oxygen Species and cAMP/PKA in the Regulation of Insulin Secretion

    PubMed Central

    Li, Ning; Li, Bin; Brun, Thierry; Deffert-Delbouille, Christine; Mahiout, Zahia; Daali, Youssef; Ma, Xiao-Juan; Krause, Karl-Heinz; Maechler, Pierre

    2012-01-01

    In insulin-secreting cells, expression of NADPH oxidase (NOX), a potent source of ROS, has been reported, along with controversial findings regarding its function. Here, the role of NOXs was investigated: first by expression and cellular localization in mouse and human pancreatic islets, and then by functional studies in islets isolated from Nox isoform–specific knockout mice. Both human and mouse β-cells express NOX, in particular NOX2. With use of Nox isoform–specific knockout mice, functional analysis revealed Nox2 as the predominant isoform. In human islets, NOX2 colocalized with both insulin granules and endosome/lysosome membranes. Nox2-deficient islets stimulated with 22.8 mmol/L glucose exhibited potentiation of insulin release compared with controls, an effect confirmed with in vitro knockdown of Nox2. The enhanced secretory function in Nox2-deficient islets was associated with both lower superoxide levels and elevated cAMP concentrations. In control islets, GLP-1 and other cAMP inducers suppressed glucose-induced ROS production similarly to Nox2 deficiency. Inhibiting cAMP-dependent protein kinase reduced the secretory response in Nox2-null islets, although not in control islets. This study ascribes a new role for NOX2 in pancreatic β-cells as negative modulator of the secretory response, reducing cAMP/PKA signaling secondary to ROS generation. Results also show reciprocal inhibition between the cAMP/PKA pathway and ROS. PMID:22933115

  5. NOX REDUCTION FOR LEAN EXHAUST USING PLASMA ASSISTED CATALYSIS

    SciTech Connect

    Bhatt, B.

    2000-08-20

    Currently CARB estimates on road diesel vehicles contribute 50% of the NOX and 78% of the particulates being discharged from mobile sources. Diesel emissions obviously must be reduced if future air quality targets are to be met. A critical technological barrier exists because there are no commercial technologies available, which can reduce NOX from diesel (lean), exhaust containing 5-15% O2 concentration. One promising approach to reducing NOX and particulates from diesel exhaust is to use a combination of plasma with catalyst. Plasma can be generated thermally or non-thermally. Thermal plasma is formed by heating the system to an exceedingly high temperature (>2000 C). High temperature requirements for plasma makes thermal plasma inefficient and requires skillful thermal management and hence is considered impractical for mobile applications. Non-thermal plasma directs electrical energy into the creation of free electrons, which in turn react with gaseous species thus creating plasma. A combination of non-thermal plasma with catalysts can be referred to Plasma Assisted Catalysts or PAC. PAC technology has been demonstrated in stationary sources where non-thermal plasma catalysis is carried out in presence of NH3 as a reductant. In stationary applications NO is oxidized to HNO3 and then into ammonium nitrate where it is condensed and removed. This approach is impractical for mobile application because of the ammonia requirement and the ultimate mechanism by which NOX is removed. However, if a suitable catalyst can be found which can use onboard fuel as reductant then the technology holds a considerable promise. NOX REDUCTION FOR LEAN EXHAUST USING PLASMA ASSISTED CATALYSIS Ralph Slone, B. Bhatt and Victor Puchkarev NOXTECH INC. In addition to the development of an effective catalyst, a non-thermal plasma reactor needs be scaled and demonstrated along with a reliable and cost effective plasma power source and onboard HC source needs to be proven. Under the work

  6. Trends in concentrations of atmospheric gaseous and particulate species in rural eastern Tennessee as related to primary emission reductions

    NASA Astrophysics Data System (ADS)

    Tanner, R. L.; Bairai, S. T.; Mueller, S. F.

    2015-09-01

    Air quality measurements at Look Rock, Tennessee - on the western edge of the Great Smoky Mountains National Park - were begun in 1980 and expanded during the 1980s to a National Park Service (NPS) IMPROVE network station. Measurements were expanded again by the Tennessee Valley Authority (TVA, 1999-2007) to examine the effects of electric generating unit (EGU) emission reductions of SO2 and NOx on air quality at the station. Analysis of temporal trends (1999-2013) has been conducted at the site in collaboration with activities related to the 2013 Southeast Atmosphere Study (SAS) at Look Rock and other southeastern US locations. Key findings from these trend studies include the observation that primary pollutant levels have consistently tracked emission reductions from EGUs and other primary sources in the region, but reductions in secondary pollutants such as particulate sulfate and, specifically, ozone have been smaller compared to reductions in primary emissions. Organic carbonaceous material (OM) remains a major contributor (30-40 % in the period 2009-2013) to fine particulate mass at the site, as confirmed by ACSM measurements at the site in 2013. A large portion (65-85 %) of carbon in OM derives from modern carbon sources based on 14C measurements. Important parameters affecting ozone levels, fine mass, and visibility also include the specific diurnal meteorology at this ridge-top site, its location in a predominantly mixed-deciduous forest, and the presence of primary sources of precursors at distances of 50-500 km from the site in all directions.

  7. Trends in concentrations of atmospheric gaseous and particulate species in rural eastern Tennessee as related to primary emissions reductions

    NASA Astrophysics Data System (ADS)

    Tanner, R. L.; Bairai, S. T.; Mueller, S. F.

    2015-05-01

    Air quality measurements at Look Rock, Tennessee - on the western edge of the Great Smoky Mountains National Park - were begun in 1980 and expanded during the 1980s to a National Park Service (NPS) IMPROVE network station. Measurements were expanded again by the Tennessee Valley Authority (TVA, 1999-2007) to examine the effects of electric generating unit (EGU) emission reductions of SO2 and NOx on air quality at the station. Analysis of temporal trends (1999-2013) has been conducted at the site in collaboration with activities related to the 2013 Southeast Atmosphere Study (SAS) at Look Rock and other southeastern US locations. Key findings from these trend studies include the observation that primary pollutant levels have consistently tracked emissions reductions from EGUs and other primary sources in the region but reductions in secondary pollutants such as particulate sulfate and, specifically, ozone have been smaller compared to reductions in primary emissions. Organic carbonaceous material (OM) remains a major contributor (30-40% in the period 2009-2013) to fine particulate mass at the site, as confirmed by ACSM measurements at the site in 2013. A large portion (65-85%) of carbon in OM derives from modern carbon sources based on 14C measurements. Important parameters affecting ozone levels, fine mass and visibility also include the specific diurnal meteorology at this ridge-top site, its location in a predominantly mixed-deciduous forest, and the presence of primary sources of precursors at distances of 50-500 km from the site in all directions.

  8. Relationship of peroxyacetyl nitrate to active and total odd nitrogen at northern high latitudes - Influence of reservoir species on NO(x) and O3

    NASA Technical Reports Server (NTRS)

    Singh, H. B.; Herlth, D.; O'Hara, D.; Zahnle, K.; Bradshaw, J. D.; Sandholm, S. T.; Talbot, R.; Crutzen, P. J.; Kanakidou, M. A.

    1992-01-01

    The partitioning of relative nitrogen in the Arctic and the sub-Arctic troposphere based on measurements conducted during the 1988 Arctic Boundary Layer Expedition (ABLE 3A) is described. The first set of comprehensive odd nitrogen and O3 measurements from the Arctic/sub-Arctic free troposphere shows that a highly aged air mass that has persisted under very cold conditions is present. A large fraction of the odd nitrogen appears to be present in the form of reservoir species such as PAN. Significant quantities of as yet unknown reactive nitrogen species, such as complex alkyl nitrates and pernitrates, are expected to be present. Together with PAN, these nitrate and pernitrate reservoir species could control the entire NO(x) availability of the high-latitude troposphere and in turn influence the O3 photochemistry of the region. The role of PAN in influencing the O3 reservoir is shown to be important and may be responsible for the increasing O3 temporal trend observed at high latitudes.

  9. The Effects of Gaseous Ozone and Nitric Acid Deposition on two Crustose Lichen Species From Joshua Tree National Park

    NASA Astrophysics Data System (ADS)

    Hessom, Elizabeth Curie

    Lichens are dependent on atmospheric deposition for much of their water and nutrients, and due to their sensitivity to pollutants, are commonly used as bioindicators for air quality. While studies have focused on epiphytic (tree dwelling) lichens as bioindicators, virtually nothing is known about crustose (rock dwelling) lichens. The atmospheric pollutants ozone (O 3) and nitric acid (HNO3) are two major pollutants found within the Los Angeles Basin. While recent O3 research suggests it does not significantly affect lichen growth, HNO3 appears to be phytotoxic to some lichens. As both of these pollutants are deposited downwind from the L.A. basin into Joshua Tree National Park (JOTR), lichen species located in the park may provide a sensitive indicator of pollution effects. This research studied two lichen species of particular interest from Joshua Tree National Park, Lobothallia praeradiosa (Nyl.) Hafellner, and Acarospora socialis H. Magn., both of which are crustose species with unknown sensitivities to O3, as well as hypothesized and unknown sensitivities to nitrogen compounds, respectively. Little research exists for either species, possibly because of the difficulty in working with crustose lichens. This research attempted to expand the background knowledge of these species by exposing them to varying levels of O3 and HNO3, to ascertain their physiological responses. Physiological measures of chlorophyll fluorescence, dark respiration, microscopic imaging, and lichen washes (as a proxy for membrane leakage), were measured throughout the exposure period. Results indicated that both species had similar sensitivities to O3 and HNO3. Both species registered physical damage during the O3 fumigation, as well as a decrease in respiration. Neither species showed major physical damage to HNO3, but both manifested a decrease in chlorophyll fluorescence, suggesting damage to the photosynthetic systems of the algae symbiont. These results suggest that both of these

  10. Electron beam treatment of exhaust gas with high NOx concentration

    NASA Astrophysics Data System (ADS)

    Licki, Janusz; Chmielewski, Andrzej G.; Pawelec, Andrzej; Zimek, Zbigniew; Witman, Sylwia

    2014-05-01

    Simulated exhaust gases with a high NOx concentration, ranging from 200 to 1700 ppmv, were irradiated by an electron beam from an accelerator. In the first part of this study, only exhaust gases were treated. Low NOx removal efficiencies were obtained for high NOx concentrations, even with high irradiation doses applied. In the second part of study, gaseous ammonia or/and vapor ethanol were added to the exhaust gas before its inlet to the plasma reactor. These additions significantly enhanced the NOx removal efficiency. The synergistic effect of high SO2 concentration on NOx removal was observed. The combination of electron beam treatment with the introduction of the above additions and with the performance of irradiation under optimal parameters ensured high NOx removal efficiency without the application of a solid-state catalyst.

  11. Nox regulation of smooth muscle contraction.

    PubMed

    Ritsick, Darren R; Edens, William A; Finnerty, Victoria; Lambeth, J David

    2007-07-01

    The catalytic subunit gp91phox (Nox2) of the NADPH oxidase of mammalian phagocytes is activated by microbes and immune mediators to produce large amounts of reactive oxygen species (ROS) which participate in microbial killing. Homologs of gp91phox, the Nox and Duox enzymes, were recently described in a range of organisms, including plants, vertebrates, and invertebrates such as Drosophila melanogaster. While their enzymology and cell biology are being extensively studied in many laboratories, little is known about in vivo functions of Noxes. Here, we establish and use an inducible system for RNAi to discover functions of dNox, an ortholog of human Nox5 in Drosophila. We report here that depletion of dNox in musculature causes retention of mature eggs within ovaries, leading to female sterility. In dNox-depleted ovaries and ovaries treated with a Nox inhibitor, muscular contractions induced by the neuropeptide proctolin are markedly inhibited. This functional defect results from a requirement for dNox-for the proctolin-induced calcium flux in Drosophila ovaries. Thus, these studies demonstrate a novel biological role for Nox-generated ROS in mediating agonist-induced calcium flux and smooth muscle contraction.

  12. PREPARING TO MEASURE THE EFFECTS OF THE NOX SIP CALL - METHODS FOR AMBIENT AIR MONITORING OF NO, NO2, NOY AND INDIVIDUAL NOZ SPECIES

    EPA Science Inventory

    The capping of stationary source emissions of NOx in 22 states and the District of Columbia is federally mandated by the NOx SIP Call legislation with the intended purpose of reducing downwind ozone concentrations. Monitors for NO, NO2, and the reactive oxides of nitrogen into ...

  13. Immunohistochemical localization of Nox in mouse circumvallate papillae.

    PubMed

    Kashiwabara, Yoshiaki; Ambe, Kimiharu; Nakagawa, Toshihiro; Watanabe, Hiroki

    2015-12-01

    Recently it has been reported that reactive oxygen species plays an important role in several physiological processes. Reactive oxygen species are generated by reactive oxygen-synthesizing enzymes (Nox). We immunohistochemically investigated expression and localization of the Nox family in a mouse circumvallate papillae. In the epithelium of the circumvallate papilla, Nox 1, 2, 3, and 4, Noxo1, and Noxa1 were expressed. In the circumvallate papilla, Nox2 was more weakly expressed in the lateral than in the upper part, and Nox3 was not expressed. In the taste buds, Nox 1, 2, 3, and 4, Noxo1, and Noxa1 were expressed; the Nox expression pattern varied with the cell type. In type II cells, Nox 1, 3, and 4, Noxo1, and Noxa1 were expressed. In type III cells, Nox2, besides Nox 1, 3, and 4, Noxo1, and Noxa1, were specifically expressed, unlike in other taste bud cells. In the mouse circumvallate papilla, Nox is always expressed, suggesting the generation of reactive oxygen species. Of note, all cells comprising taste buds expressed Nox, with each showing a specific Nox expression pattern.

  14. Impact of sulfation and desulfation on NOx reduction using Cu-chabazite SCR catalysts

    DOE PAGES

    Brookshear, Daniel William; Nam, Jeong -Gil; Nguyen, Ke; Toops, Todd J.; Binder, Andrew J.

    2015-06-05

    This bench reactor study investigates the impact of gaseous sulfur on the NOx reduction activity of Cu-chabazite SCR (Cu-CHA) catalysts at SO2 concentrations representative of marine diesel engine exhaust. After two hours of 500 ppm SO2 exposure at 250 and 400 °C in the simulated diesel exhaust gases, the NOx reduction activity of the sulfated Cu-CHA SCR catalysts is severely degraded at evaluation temperatures below 250 °C; however, above 250 °C the impact of sulfur exposure is minimal. EPMA shows that sulfur is located throughout the washcoat and along the entire length of the sulfated samples. Interestingly, BET measurements revealmore » that the sulfated samples have a 20% decrease in surface area. Moreover, the sulfated samples show a decrease in NOx/nitrate absorption during NO exposure in a DRIFTS reactor which suggests that Cu sites in the catalyst are blocked by the presence of sulfur. SO2 exposure also results in an increase in NH3 storage capacity, possibly due to the formation of ammonium sulfate species in the sulfated samples. In all cases, lean thermal treatments as low as 500 °C reverse the effects of sulfur exposure and restore the NOx reduction activity of the Cu-CHA catalyst to that of the fresh condition.« less

  15. Gaseous Detectors

    NASA Astrophysics Data System (ADS)

    Titov, Maxim

    Since long time, the compelling scientific goals of future high-energy physics experiments were a driving factor in the development of advanced detector technologies. A true innovation in detector instrumentation concepts came in 1968, with the development of a fully parallel readout for a large array of sensing elements - the Multi-Wire Proportional Chamber (MWPC), which earned Georges Charpak a Nobel prize in physics in 1992. Since that time radiation detection and imaging with fast gaseous detectors, capable of economically covering large detection volumes with low mass budget, have been playing an important role in many fields of physics. Advances in photolithography and microprocessing techniques in the chip industry during the past decade triggered a major transition in the field of gas detectors from wire structures to Micro-Pattern Gas Detector (MPGD) concepts, revolutionizing cell-size limitations for many gas detector applications. The high radiation resistance and excellent spatial and time resolution make them an invaluable tool to confront future detector challenges at the next generation of colliders. The design of the new micro-pattern devices appears suitable for industrial production. Novel structures where MPGDs are directly coupled to the CMOS pixel readout represent an exciting field allowing timing and charge measurements as well as precise spatial information in 3D. Originally developed for the high-energy physics, MPGD applications have expanded to nuclear physics, photon detection, astroparticle and neutrino physics, neutron detection, and medical imaging.

  16. Unchanged NADPH Oxidase Activity in Nox1-Nox2-Nox4 Triple Knockout Mice: What Do NADPH-Stimulated Chemiluminescence Assays Really Detect?

    PubMed

    Rezende, Flávia; Löwe, Oliver; Helfinger, Valeska; Prior, Kim-Kristin; Walter, Maria; Zukunft, Sven; Fleming, Ingrid; Weissmann, Norbert; Brandes, Ralf P; Schröder, Katrin

    2016-03-01

    NADPH oxidases of the Nox family are considered important sources of cellular reactive oxygen species (ROS) production. This conclusion is, in part, based on the ability of NADPH to elicit a chemiluminescence signal in tissue/cell homogenates or membrane preparations in the presence of enhancers such as lucigenin, luminol, or L012. However, the ability of these particular assays to specifically detect Nox activity and Nox-derived ROS has not been proven. In this study, we demonstrate that combined knockout of the three main Nox enzymes of the mouse (Nox1-Nox2-Nox4 triple knockout) had no impact on NADPH-stimulated chemiluminescence signals in the aorta, heart, and kidney homogenates. In the NADPH-stimulated membrane assays, no effect of in vivo angiotensin II pretreatment or deletion of Nox enzymes was observed. In in vitro studies in HEK293 cells, the overexpression of Nox5 or Nox4 markedly increased ROS production in intact cells, whereas overexpression of Nox5 or Nox4 had no influence on the signal in membrane assays. In contrast, overexpression of nitric oxide synthase or cytochrome P450 enzymes resulted in an increased chemiluminescence signal in isolated membranes. On the basis of these observations, we propose the hypothesis that NADPH-stimulated chemiluminescence-based membrane assays, as currently used, do not reflect Nox activity. PMID:25906178

  17. PVN adenovirus-siRNA injections silencing either NOX2 or NOX4 attenuate aldosterone/NaCl-induced hypertension in mice.

    PubMed

    Xue, Baojian; Beltz, Terry G; Johnson, Ralph F; Guo, Fang; Hay, Meredith; Johnson, Alan Kim

    2012-02-01

    Mineralocorticoid excess increases superoxide production by activating NADPH oxidase (NOX), and intracerebroventricular infusions of NADPH oxidase inhibitors attenuate aldosterone (Aldo)/salt-induced hypertension. It has been hypothesized that increased reactive oxygen species (ROS) in the brain may be a key mechanism in the development of hypertension. The present study investigated the brain regional specificity of NADPH oxidase and the role of NOX2 and NOX4 NADPH oxidase subunits in the hypothalamic paraventricular nucleus (PVN) in Aldo/salt-induced hypertension. PVN injections of adenoviral vectors expressing small interfering (si)RNA targeting NOX2 (AdsiRNA-NOX2) or NOX4 (AdsiRNA-NOX4) mRNAs were used to knock down NOX2 and NOX4 proteins. Three days later, delivery of Aldo (0.2 mg·kg(-1)·day(-1) sc) via osmotic pump commenced and 1% NaCl was provided in place of water. PVN injections of either AdsiRNA-NOX2 or AdsiRNA-NOX4 significantly attenuated the development of Aldo/NaCl-induced hypertension. In an additional study, Aldo/salt-induced hypertension was also significantly attenuated in NOX2 (genomic) knockout mice compared with wild-type controls. When animals from both functional studies underwent ganglionic blockade, there was a reduced fall in blood pressure in the NOX2 and NOX4 knockdown/knockout mice. Western blot analyses of the PVN of siRNA-NOX2- or siRNA-NOX4-injected mice confirmed a marked reduction in the expression of NOX2 or NOX4 protein. In cultured PVN neurons, silencing either NOX2 or NOX4 protein production by culturing PVN cells with siRNA-NOX2 or siRNA-NOX4 attenuated Aldo-induced ROS. These data indicate that both NOX2 and NOX4 in the PVN contribute to elevated sympathetic activity and the hypertensivogenic actions induced by mineralocorticoid excess. PMID:22140041

  18. A denuder-impinger system with in situ derivatization followed by gas chromatography-mass spectrometry for the determination of gaseous iodine-containing halogen species.

    PubMed

    Huang, Ru-Jin; Hoffmann, Thorsten

    2008-11-14

    Reactive iodine species have been suggested to play an important role in the atmosphere (e.g. tropospheric ozone depletion, coastal new particle formation). However, there still exist major uncertainties about their atmospheric chemistry, mostly due to the lack of analytical approaches for the accurate speciation of certain key compounds. In this study, 1,3,5-trimethoxybenzene (1,3,5-TMB)-coated denuder proved to be suitable for the differentiation between gaseous interhalogens (iodine monochloride (ICl), iodine monobromide (IBr)) and molecular iodine (I2) based on a selective collection/derivatization method. The results of the denuder sampling were compared with the results of impinger sampling in water, methanol and carbon tetrachloride solutions of 1,3,5-TMB. ICl and IBr are converted into 1-iodo-2,4,6-trimethoxybenzene (1-iodo-2,4,6-TMB) and 1-bromo-2,4,6-trimethoxybenzene (1-bromo-2,4,6-TMB), respectively, in the denuder systems. The respective collection efficiency is 99.2% for ICl and 92.6% for IBr, at 500mLmin(-1) gas flow rate. The collection efficiency for I2 is lower than 1% in the same denuder system, but significantly increases to about 90% in the aqueous 1,3,5-TMB loaded impinger. The denuder-impinger coupled system was then used to differentiate and to collect the ICl, IBr and I2 gas mixtures, followed by gas chromatography-ion trap mass spectrometry (GC-MS) determination. The precision of the method is in general better than 9.1%. The parameters affecting denuder operation including sampling flow rate, sampling duration, and relative humidity have been evaluated. The presented method provides an attractive protocol for iodine species analysis for atmospheric chemistry research.

  19. Low NO(x) potential of gas turbine engines

    NASA Technical Reports Server (NTRS)

    Tacina, Robert R.

    1990-01-01

    The purpose is to correlate emission levels of gas turbine engines. The predictions of NO(x) emissions are based on a review of the literature of previous low NO(x) combustor programs and analytical chemical kinetic calculations. Concepts included in the literature review consisted of lean-premixed-prevaporized (LPP), rich burn/quick quench/lean burn (RQL), and direct injection. The NO(x) emissions were found to be an exponential function of adiabatic combustion temperature over a wide range of inlet temperatures, pressures and (lean) fuel-air ratios. A simple correlation of NO(x) formation with time was not found. The LPP and direct injection (using gaseous fuels) concepts have the lowest NO(x) emissions of the three concepts. The RQL data has higher values of NO(x) than the LPP concept, probably due to the stoichiometric temperatures and NO(x) production that occur during the quench step. Improvements in the quick quench step could reduce the NO(x) emissions to the LPP levels. The low NO(x) potential of LPP is offset by the operational disadvantages of its narrow stability limits and its susceptibility to autoignition/flashback. The Rich-Burn/Quick-Quench/Lean-Burn (RQL) and the direct injection concepts have the advantage of wider stability limits comparable to conventional combustors.

  20. [NADPH oxidases, Nox: new isoenzymes family].

    PubMed

    Chuong Nguyen, Minh Vu; Lardy, Bernard; Paclet, Marie-Hélène; Rousset, Francis; Berthier, Sylvie; Baillet, Athan; Grange, Laurent; Gaudin, Philippe; Morel, Françoise

    2015-01-01

    NADPH oxidases, Nox, are a family of isoenzymes, composed of seven members, whose sole function is to produce reactive oxygen species (ROS). Although Nox catalyze the same enzymatic reaction, they acquired from a common ancestor during evolution, specificities related to their tissue expression, subcellular localization, activation mechanisms and regulation. Their functions could vary depending on the pathophysiological state of the tissues. Indeed, ROS are not only bactericidal weapons in phagocytes but also essential cellular signaling molecules and their overproduction is involved in chronic diseases and diseases of aging. The understanding of the mechanisms involved in the function of Nox and the emergence of Nox inhibitors, require a thorough knowledge of their nature and structure. The objectives of this review are to highlight, in a structure/function approach, the main similar and differentiated properties shared by the human Nox isoenzymes.

  1. NOx production in lightning

    NASA Technical Reports Server (NTRS)

    Chameides, W. L.; Stedman, D. H.; Dickerson, R. R.; Rusch, D. W.; Cicerone, R. J.

    1977-01-01

    The rate of odd nitrogen (NOx) production by electrical discharge through air was theoretically and experimentally estimated to be about 60,000 trillion NOx molecules per joule. The theoretical treatment employed a cylindrical shock-wave solution to calculate the rate of NOx production in high temperature reactions. The limits obtained were experimentally verified by subjecting a regulated air flow to electrical discharges followed by a measurement of NOx production using chemiluminescence. These measurements also indicated that water vapor content has no detectable effect on the NOx production rate. The results imply that lightning is a significant source of NOx, producing about 30-40 megatons NOx-N per year and possibly accounting for as much as 50% of the total atmospheric NOx source.

  2. RhoA/Rho kinase mediates TGF-β1-induced kidney myofibroblast activation through Poldip2/Nox4-derived reactive oxygen species.

    PubMed

    Manickam, Nagaraj; Patel, Mandakini; Griendling, Kathy K; Gorin, Yves; Barnes, Jeffrey L

    2014-07-15

    The small G proteins Rac1 and RhoA regulate actin cytoskeleton, cell shape, adhesion, migration, and proliferation. Recent studies in our laboratory have shown that NADPH oxidase Nox4-derived ROS are involved in transforming growth factor (TGF)-β1-induced rat kidney myofibroblast differentiation assessed by the acquisition of an α-smooth muscle actin (α-SMA) phenotype and expression of an alternatively spliced fibronectin variant (Fn-EIIIA). Rac1 and RhoA are essential in signaling by some Nox homologs, but their role as effectors of Nox4 in kidney myofibroblast differentiation is not known. In the present study, we explored a link among Rac1 and RhoA and Nox4-dependent ROS generation in TGF-β1-induced kidney myofibroblast activation. TGF-β1 stimulated an increase in Nox4 protein expression, NADPH oxidase activity, and abundant α-SMA and Fn-EIIIA expression. RhoA but not Rac1 was involved in TGF-β1 induction of Nox4 signaling of kidney myofibroblast activation. TGF-β1 stimulated active RhoA-GTP and increased Rho kinase (ROCK). Inhibition of RhoA with small interfering RNA and ROCK using Y-27632 significantly reduced TGF-β1-induced stimulation of Nox4 protein, NADPH oxidase activity, and α-SMA and Fn-EIIIA expression. Treatment with diphenyleneiodonium, an inhibitor of NADPH oxidase, did not decrease RhoA activation but inhibited TGF-β1-induced α-SMA and Fn-EIIIA expression, indicating that RhoA is upstream of ROS generation. RhoA/ROCK also regulated polymerase (DNA-directed) δ-interacting protein 2 (Poldip2), a newly discovered Nox4 enhancer protein. Collectively, these data indicate that RhoA/ROCK is upstream of Poldip2-dependent Nox4 regulation and ROS production and induces redox signaling of kidney myofibroblast activation and may broader implications in the pathophysiology of renal fibrosis.

  3. NOX4 regulates autophagy during energy deprivation.

    PubMed

    Sciarretta, Sebastiano; Volpe, Massimo; Sadoshima, Junichi

    2014-04-01

    NADPH oxidase is a cellular enzyme devoted to the production of reactive oxygen species (ROS). NOX4 and NOX2 are the main isoforms of NADPH oxidase in the cardiovascular system. In our recent study, we demonstrated that NOX4, but not NOX2, is a critical mediator of the cardiomyocyte adaptive response to energy stress. NOX4 activity and protein levels are increased in the endoplasmic reticulum (ER) but not in mitochondria of cardiomyocytes during the early phase of energy deprivation. NOX4-derived production of ROS in the ER is a critical event that activates autophagy through stimulation of the EIF2AK3/PERK-EIF2S1/eIF-2α-ATF4 pathway. NOX4-dependent autophagy is an important mechanism to preserve cellular energy and limit cell death in energy-deprived cardiomyocytes. Aside from elucidating a crucial physiological function of NOX4 during cellular energy stress, our study dissects a novel signaling mechanism that regulates autophagy under this condition.

  4. NOX4 regulates autophagy during energy deprivation

    PubMed Central

    Sciarretta, Sebastiano; Volpe, Massimo; Sadoshima, Junichi

    2014-01-01

    NADPH oxidase is a cellular enzyme devoted to the production of reactive oxygen species (ROS). NOX4 and NOX2 are the main isoforms of NADPH oxidase in the cardiovascular system. In our recent study, we demonstrated that NOX4, but not NOX2, is a critical mediator of the cardiomyocyte adaptive response to energy stress. NOX4 activity and protein levels are increased in the endoplasmic reticulum (ER) but not in mitochondria of cardiomyocytes during the early phase of energy deprivation. NOX4-derived production of ROS in the ER is a critical event that activates autophagy through stimulation of the EIF2AK3/PERK-EIF2S1/eIF-2α-ATF4 pathway. NOX4-dependent autophagy is an important mechanism to preserve cellular energy and limit cell death in energy-deprived cardiomyocytes. Aside from elucidating a crucial physiological function of NOX4 during cellular energy stress, our study dissects a novel signaling mechanism that regulates autophagy under this condition. PMID:24492492

  5. Deficiency of NOX1 or NOX4 Prevents Liver Inflammation and Fibrosis in Mice through Inhibition of Hepatic Stellate Cell Activation

    PubMed Central

    Lan, Tian; Kisseleva, Tatiana; Brenner, David A.

    2015-01-01

    Reactive oxygen species (ROS) produced by nicotinamide adenine dinucleotide phosphate oxidase (NOX) play a key role in liver injury and fibrosis. Previous studies demonstrated that GKT137831, a dual NOX1/4 inhibitor, attenuated liver fibrosis in mice as well as pro-fibrotic genes in hepatic stellate cells (HSCs) as well as hepatocyte apoptosis. The effect of NOX1 and NOX4 deficiency in liver fibrosis is unclear, and has never been directly compared. HSCs are the primary myofibroblasts in the pathogenesis of liver fibrosis. Therefore, we aimed to determine the role of NOX1 and NOX4 in liver fibrosis, and investigated whether NOX1 and NOX4 signaling mediates liver fibrosis by regulating HSC activation. Mice were treated with carbon tetrachloride (CCl4) to induce liver fibrosis. Deficiency of either NOX1 or NOX4 attenuates liver injury, inflammation, and fibrosis after CCl4 compared to wild-type mice. NOX1 or NOX4 deficiency reduced lipid peroxidation and ROS production in mice with liver fibrosis. NOX1 and NOX4 deficiency are approximately equally effective in preventing liver injury in the mice. The NOX1/4 dual inhibitor GKT137831 suppressed ROS production as well as inflammatory and proliferative genes induced by lipopolysaccharide (LPS), platelet-derived growth factor (PDGF), or sonic hedgehog (Shh) in primary mouse HSCs. Furthermore, the mRNAs of proliferative and pro-fibrotic genes were downregulated in NOX1 and NOX4 knock-out activated HSCs (cultured on plastic for 5 days). Finally, NOX1 and NOX4 protein levels were increased in human livers with cirrhosis compared with normal controls. Thus, NOX1 and NOX4 signaling mediates the pathogenesis of liver fibrosis, including the direct activation of HSC. PMID:26222337

  6. Nitric oxide-sensing H-NOX proteins govern bacterial communal behavior.

    PubMed

    Plate, Lars; Marletta, Michael A

    2013-11-01

    Heme-nitric oxide/oxygen binding (H-NOX) domains function as sensors for the gaseous signaling agent nitric oxide (NO) in eukaryotes and bacteria. Mammalian NO signaling is well characterized and involves the H-NOX domain of soluble guanylate cyclase. In bacteria, H-NOX proteins interact with bacterial signaling proteins in two-component signaling systems or in cyclic-di-GMP metabolism. Characterization of several downstream signaling processes has shown that bacterial H-NOX proteins share a common role in controlling important bacterial communal behaviors in response to NO. The H-NOX pathways regulate motility, biofilm formation, quorum sensing, and symbiosis. Here, we review the latest structural and mechanistic studies that have elucidated how H-NOX domains selectively bind NO and transduce ligand binding into conformational changes that modulate activity of signaling partners. Furthermore, we summarize the recent advances in understanding the physiological function and biochemical details of the H-NOX signaling pathways.

  7. Pollutant Emissions and Lean Blowoff Limits of Fuel Flexible Burners Operating on Gaseous Renewable and Fossil Fuels

    NASA Astrophysics Data System (ADS)

    Colorado, Andres

    This study provides an experimental and numerical examination of pollutant emissions and stability of gaseous fueled reactions stabilized with two premixed-fuel-flexible and ultra-low NOx burner technologies. Both burners feature lean combustion technology to control the formation of nitrogen oxides (NOx). The first fuel--flexible burner is the low-swirl burner (LSB), which features aerodynamic stabilization of the reactions with a divergent flow-field; the second burner is the surface stabilized combustion burner (SSCB), which features the stabilization of the reactions on surface patterns. For combustion applications the most commonly studied species are: NOx, carbon monoxide (CO), and unburned hydrocarbons (UHC). However these are not the only pollutants emitted when burning fossil fuels; other species such as nitrous oxide (N2O), ammonia (NH3) and formaldehyde (CH2O) can be directly emitted from the oxidation reactions. Yet the conditions that favor the emission of these pollutants are not completely understood and require further insight. The results of this dissertation close the gap existing regarding the relations between emission of pollutants species and stability when burning variable gaseous fuels. The results of this study are applicable to current issues such as: 1. Current combustion systems operating at low temperatures to control formation of NOx. 2. Increased use of alternative fuels such as hydrogen, synthetic gas and biogas. 3. Increasing recognition of the need/desire to operate combustion systems in a transient manner to follow load and to offset the intermittency of renewable power. 4. The recent advances in measurement methods allow us to quantify other pollutants, such as N 2O, NH3 and CH2O. Hence in this study, these pollutant species are assessed when burning natural gas (NG) and its binary mixtures with other gaseous fuels such as hydrogen (H2), carbon dioxide (CO2), ethane (C 2H6) and propane (C3H8) at variable operation modes including

  8. Reactions of NO2 with BaO/Pt(111) Model Catalysts: The Effects of BaO Film Thickness and NO2 Pressure on the Formation of Ba(NOx)2 Species

    SciTech Connect

    Mudiyanselage, Kumudu; Yi, Cheol-Woo; Szanyi, Janos

    2011-05-31

    The adsorption and reaction of NO2 on BaO (<1, ~3, and >20 monolayer equivalent (MLE))/Pt(111) model systems were studied with temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and infrared reflection absorption spectroscopy (IRAS) under ultra-high vacuum (UHV) as well as elevated pressure conditions. NO2 reacts with sub-monolayer BaO (<1 MLE) to form nitrites only, whereas the reaction of NO2 with BaO (~3 MLE)/Pt(111) produces mainly nitrites and a small amount of nitrates under UHV conditions (PNO2 ~ 1.0 × 10-9 Torr) at 300 K. In contrast, a thick BaO(>20 MLE) layer on Pt(111) reacts with NO2 to form nitrite-nitrate ion pairs under the same conditions. At elevated NO2 pressures (≥ 1.0 × 10-5 Torr), however, BaO layers at all these three coverages convert to amorphous barium nitrates at 300 K. Upon annealing to 500 K, these amorphous barium nitrate layers transform into crystalline phases. The thermal decomposition of the thus-formed Ba(NOx)2 species is also influenced by the coverage of BaO on the Pt(111) substrate: at low BaO coverages, these species decompose at significantly lower temperatures in comparison with those formed on thick BaO films due to the presence of Ba(NOx)2/Pt interface where the decomposition can proceed at lower temperatures. However, the thermal decomposition of the thick Ba(NO3)2 films follows that of bulk nitrates. Results obtained from these BaO/Pt(111) model systems under UHV and elevated pressure conditions clearly demonstrate that both the BaO film thickness and the applied NO2 pressure are critical in the Ba(NOx)2 formation and subsequent thermal decomposition processes.

  9. Formation of NOx precursors during Chinese pulverized coal pyrolysis in an arc plasma jet

    SciTech Connect

    Wei-ren Bao; Jin-cao Zhang; Fan Li; Li-ping Chang

    2007-08-15

    The formation of NOx precursors (HCN and NH{sub 3}) from the pyrolysis of several Chinese pulverized coals in an arc plasma jet was investigated through both thermodynamic analysis of the C-H-O-N system and experiments. Results of thermodynamic analysis show that the dominant N-containing gaseous species is HCN together with a small amount of ammonia above the temperature of 2000 K. The increase of H content advances the formation of HCN and NH{sub 3}, but the yields of HCN and NH{sub 3} are decreased with a high concentration of O in the system. These results are accordant with the experimental data. The increasing of input power promotes the formation of HCN and NH{sub 3} from coal pyrolysis in an arc plasma jet. Tar-N is not formed during the process. The yield of HCN changes insignificantly with the changing of the residence time of coal particles in the reactor, but that of NH{sub 3} decreases as residence times increase because of the relative instability at high temperature. Adsorption and gasification of CO{sub 2} on the coal surface also can restrain the formation of HCN and NH{sub 3} compare to the results in an Ar plasma jet. Yields of HCN and NH{sub 3} are sensitive to the coal feeding rate, indicating that NOx precursors could interact with the nascent char to form other N-containing species. The formation of HCN and NH{sub 3} during coal pyrolysis in a H{sub 2}/Ar plasma jet are not dependent on coal rank. The N-containing gaseous species is released faster than others in the volatiles during coal pyrolysis in an arc plasma jet, and the final nitrogen content in the char is lower than that in the parent coal, which it is independent of coal type. 16 refs., 9 figs., 1 tab.

  10. Collection of NO and NO2 for isotopic analysis of NO(x) emissions.

    PubMed

    Fibiger, Dorothy L; Hastings, Meredith G; Lew, Audrey F; Peltier, Richard E

    2014-12-16

    There have been several measurements made of the nitrogen isotopic composition of gaseous NOx (NOx = NO + NO2) from various emission sources, utilizing a wide variety of methods to collect the NOx in solution as nitrate or nitrite. However, previous collection techniques have not been verified for complete or efficient capture of NOx such that the isotopic composition of NOx remains unaltered during collection. Here, we present a method of collecting NOx (NO + NO2) in solution as nitrate to evaluate the nitrogen isotopic composition of the NOx (δ(15)N-NOx). Using a 0.25 M KMnO4 and 0.5 M NaOH solution, quantitative NOx collection was achieved under a variety of conditions in laboratory and field settings, allowing for isotopic analysis without correcting for fractionations. The uncertainty across the entire analytic procedure is ±1.5‰ (1σ). With this method, a more robust inventory of NOx source isotopic composition is possible, which has implications for studies of air quality and acid deposition. PMID:25415365

  11. Solid and Gaseous Fuels.

    ERIC Educational Resources Information Center

    Schultz, Hyman; And Others

    1989-01-01

    This review covers methods of sampling, analyzing, and testing coal, coke, and coal-derived solids and methods for the chemical, physical, and instrumental analyses of gaseous fuels. The review covers from October 1986, to September 1988. (MVL)

  12. Newly developed gaseous photomultiplier

    NASA Astrophysics Data System (ADS)

    Tokanai, Fuyuki; Moriya, Toru; Takeyama, Mirei; Sakurai, Hirohisa; Gunji, Shuichi; Sumiyoshi, Takayuki; Ito, Takayuki; Sugiyama, Hirioyuki; Okada, Teruyuki; Ohishi, Noboru; Kishimoto, Syunji

    2014-12-01

    A new micromesh gas (Micromegas) detector has been developed for a gaseous photomultiplier tube (PMT) with a bialkali photocathode. A basic performance test of the Micromegas detector was carried out for a Ne (90%) + CF4 (10%) gas mixture using an X-ray beam. We constructed gaseous PMTs with a bialkali photocathode and Micromegas detectors. The photoelectron collection efficiencies in several gases and the suppression of ion feedback were investigated.

  13. Nox family NADPH oxidases: Molecular mechanisms of activation.

    PubMed

    Brandes, Ralf P; Weissmann, Norbert; Schröder, Katrin

    2014-11-01

    NADPH oxidases of the Nox family are important enzymatic sources of reactive oxygen species (ROS). Numerous homologue-specific mechanisms control the activity of this enzyme family involving calcium, free fatty acids, protein-protein interactions, intracellular trafficking, and posttranslational modifications such as phosphorylation, acetylation, or sumoylation. After a brief review on the classic pathways of Nox activation, this article will focus on novel mechanisms of homologue-specific activity control and on cell-specific aspects which govern Nox activity. From these findings of the recent years it must be concluded that the activity control of Nox enzymes is much more complex than anticipated. Moreover, depending on the cellular activity state, Nox enzymes are selectively activated or inactivated. The complex upstream signaling aspects of these events make the development of "intelligent" Nox inhibitors plausible, which selectively attenuate disease-related Nox-mediated ROS formation without altering physiological signaling ROS. This approach might be of relevance for Nox-mediated tissue injury in ischemia-reperfusion and inflammation and also for chronic Nox overactivation as present in cancer initiation and cardiovascular disease.

  14. New Insights on NOX Enzymes in the Central Nervous System

    PubMed Central

    Nayernia, Zeynab; Jaquet, Vincent

    2014-01-01

    Abstract Significance: There is increasing evidence that the generation of reactive oxygen species (ROS) in the central nervous system (CNS) involves the NOX family of nicotinamide adenine dinucleotide phosphate oxidases. Controlled ROS generation appears necessary for optimal functioning of the CNS through fine-tuning of redox-sensitive signaling pathways, while overshooting ROS generation will lead to oxidative stress and CNS disease. Recent Advances: NOX enzymes are not only restricted to microglia (i.e. brain phagocytes) but also expressed in neurons, astrocytes, and the neurovascular system. NOX enzymes are involved in CNS development, neural stem cell biology, and the function of mature neurons. While NOX2 appears to be a major source of pathological oxidative stress in the CNS, other NOX isoforms might also be of importance, for example, NOX4 in stroke. Globally speaking, there is now convincing evidence for a role of NOX enzymes in various neurodegenerative diseases, cerebrovascular diseases, and psychosis-related disorders. Critical Issues: The relative importance of specific ROS sources (e.g., NOX enzymes vs. mitochondria; NOX2 vs. NOX4) in different pathological processes needs further investigation. The absence of specific inhibitors limits the possibility to investigate specific therapeutic strategies. The uncritical use of non-specific inhibitors (e.g., apocynin, diphenylene iodonium) and poorly validated antibodies may lead to misleading conclusions. Future Directions: Physiological and pathophysiological studies with cell-type-specific knock-out mice will be necessary to delineate the precise functions of NOX enzymes and their implications in pathomechanisms. The development of CNS-permeant, specific NOX inhibitors will be necessary to advance toward therapeutic applications. Antioxid. Redox Signal. 20: 2815–2837. PMID:24206089

  15. Environmental effects of increased coal utilization: ecological effects of gaseous emissions from coal combustion.

    PubMed Central

    Glass, N R

    1979-01-01

    This report is limited to an evaluation of the ecological and environmental effects of gaseous emissions and aerosols of various types which result from coal combustion. It deals with NOx, SOx, fine particulate, photochemical oxidant and acid precipitation as these pollutants affect natural and managed resources and ecosystems. Also, synergistic effects involving two or more pollutants are evaluated as well as ecosystem level effects of gaseous pollutants. There is a brief summary of the effects on materials and atmospheric visibility of increased coal combustion. The economic implications of ecological effects are identified to the extent they can be determined within acceptable limits. Aquatic and terrestrial effects are distinguished where the pollutants in question are clearly problems in both media. At present, acid precipitation is most abundant in the north central and northeastern states. Total SOx and NOx emissions are projected to remain high in these regions while increasing relatively more in the western than in the eastern regions of the country. A variety of ecological processes are affected and altered by air pollution. Such processes include community succession and retrogression, nutrient biogeochemical cycling, photosynthetic activity, primary and secondary productivity, species diversity and community stability. Estimates of the non health-related cost of air pollutants range from several hundred million dollars to $1.7 billion dollars per year. In general, these estimates include only those relatively easily measured considerations such as the known losses to cultivate crops from acute air pollution episodes or the cost of frequent repainting required as a result of air pollution. No substantial nationwide estimates of losses to forest productivity, natural ecosystem productivity which is tapped by domestic grazing animals and wildlife, and other significant dollar losses are available. PMID:44247

  16. Low NOx heavy fuel combustor concept program

    NASA Technical Reports Server (NTRS)

    White, D. J.; Kubasco, A. J.

    1982-01-01

    Three simulated coal gas fuels based on hydrogen and carbon monoxide were tested during an experimental evaluation with a rich lean can combustor: these were a simulated Winkler gas, Lurgi gas and Blue Water gas. All three were simulated by mixing together the necessary pure component species, to levels typical of fuel gases produced from coal. The Lurgi gas was also evaluated with ammonia addition. Fuel burning in a rich lean mode was emphasized. Only the Blue Water gas, however, could be operated in such fashion. This showed that the expected NOx signature form could be obtained, although the absolute values of NOx were above the 75 ppm goals for most operating conditions. Lean combustion produced very low NOx well below 75 ppm with the Winkler and Lurgi gases. In addition, these low levels were not significantly impacted by changes in operating conditions.

  17. Characterization of gaseous nitrogen oxides in the Lower Fraser Valley during Pacific 2001

    NASA Astrophysics Data System (ADS)

    Hayden, K. L.; Anlauf, K. G.; Li, S.-M.; Macdonald, A. M.; Bottenheim, J. W.; Brook, J. R.; Wiebe, H. A.

    2004-11-01

    From 13 August-1 September 2001, a number of gaseous chemical compounds were measured at three sites in the Lower Fraser Valley, British Columbia: (1) Slocan-in the city of Vancouver; (2) Langley-in a rural, agricultural area about 35 km southeast of Vancouver; and (3) Sumas-about 65 km inland on a forested mountain (300 m asl). Although the Langley and Sumas sites were located away from major emission sources, CO, NOx and NOy mixing ratios indicate that these sites were often impacted by anthropogenic emissions. At Langley and Slocan, NO and CO mixing ratios were highest between 0400-0700 PDT (UT=PDT-8 h) due to the buildup of fresh vehicular emissions under a nocturnal inversion. At the elevated Sumas site, during the growth of the boundary layer, upward mixing of fresh emissions was observed, delayed by 3 h compared to the other two sites. NOx was the largest component of NOy at Langley and Sumas, averaging 75-80%. At Langley, the HNO3 fraction of NOy during the afternoon ranged from 15% to 28%, compared to <10% at the other two sites. PAN was significantly lower than HNO3 at <5% of NOy at all three sites. The sum of all individual nitrogen oxide species, ∑NOyi accounted for 85% and 93% of NOy on average at Langley and Sumas, respectively. The chemical age was estimated at the three sites using the ratio (HONO+HNO3+PAN)/NOy. The daytime (1400-1800 PDT) ratios at Langley (0.19-0.40) were higher than those at either Slocan (0.04-0.12) or Sumas (0.09-0.19), mainly driven by higher HNO3 contributions to NOy. The higher ratios at Langley suggest that the extent of processing in air masses at the site during the daytime was greater than at Slocan or Sumas. At Sumas, the elevated nighttime ratios (0.05-0.29) were attributed to transport of more aged air masses to the site and the contribution of HNO3 from N2O5 hydrolysis. O3 was only weakly correlated with the oxidation products of NOx at Langley (m = 2.5 ± 9.1) and Sumas (m = 7.3 ± 8.2). Meteorological conditions

  18. Characterization of gaseous pollutants and fine particles at a rural site in the Yangtze River Delta

    NASA Astrophysics Data System (ADS)

    Chai, Fa-He; Gao, Jian; Wang, Shu-Lan; Zhang, Yue-Chong; Mu, Yujing; Mellouki, Abdelwahid

    2010-05-01

    The ambient O3, CO, NO-NO2-NOx*, SO2, NH3 and PM2.5 have been monitored at Chongming Island, a rural site in the Yangtze River Delta in the Shanghai area, from October 2008 to September 2009. In this presentation, we report the measured concentration levels, diurnal/seasonal variation, of the species of interest. An analysis of the pollutant sources is also presented. The average concentrations of O3, CO, SO2, NO, NO2, NOx*, NH3 and PM2.5 are 36.7 ppb, 0.7 ppm, 14.3 ppb, 4.8 ppb, 13.5 ppb, 19.7 ppb, 24.9 ppb, and 54.4 µg/m3, respectively. The concentration levels of the gaseous pollutants are lower than the Grades I of both the Chinese Ambient Air Quality Standards and the primary standard of US National Ambient Air Quality Standards. The diurnal profiles of the primary pollutants (CO, SO2) show peak values before noon. The NO and NOx show the similar profiles as CO in warm season, but have bimodal profiles in winter, suggesting the possibility of influence from transport emission in the season. Most of the primary pollutants have maximum values in winter, indicating the influence of fuel burning source during the heating period. O3 keeps high level in the summer. The surface concentration of O3, Ox (O3+NO2) and NO2 at the site and the satellite observed tropospheric columns O3 and NO2 have similar seasonal pattern. The PM2.5 concentration peaks in summer, which has bad correlation with AOD. The relationship among the primary pollutants indicates a significant influence of transport emission over the region. In autumn, the biomass burning emission also seems to be one of the major sources for the air pollutants.

  19. Identification of the arsenic resistance on MoO3 doped CeO2/TiO2 catalyst for selective catalytic reduction of NOx with ammonia.

    PubMed

    Li, Xiang; Li, Xiansheng; Li, Junhua; Hao, Jiming

    2016-11-15

    Arsenic resistance on MoO3 doped CeO2/TiO2 catalysts for selective catalytic reduction of NOx with NH3 (NH3-SCR) is investigated. It is found that the activity loss of CeO2-MoO3/TiO2 caused by As oxide is obvious less than that of CeO2/TiO2 catalysts. The fresh and poisoned catalysts are compared and analyzed using XRD, Raman, XPS, H2-TPR and in situ DRIFTS. The results manifest that the introduction of arsenic oxide to CeO2/TiO2 catalyst not only weakens BET surface area, surface acid sites and adsorbed NOx species, but also destroy the redox circle of Ce(4+) to Ce(3+) because of interaction between Ce and As. When MoO3 is added into CeO2/TiO2 system, the main SCR reaction path are found to be changed from the reaction between coordinated NH3 and ad-NOx species to that between an amide and gaseous NO. Additionally, for CeO2-MoO3/TiO2 catalyst, As toxic effect on active sites CeO2 can be released because of stronger As-Mo interaction. Moreover, not only are the reactable Brønsted and Lewis acid sites partly restored, but the cycle of Ce(4+) to Ce(3+) can also be free to some extent.

  20. The NADPH oxidase Nox4 and aging in the heart.

    PubMed

    Ago, Tetsuro; Matsushima, Shouji; Kuroda, Junya; Zablocki, Daniela; Kitazono, Takanari; Sadoshima, Junichi

    2010-12-01

    Oxidative stress in mitochondria is believed to promote aging. Although passive leakage of electron from the mitochondrial electron transport chain has been considered as a major source of oxidative stress in the heart and the cardiomyocytes therein, enzymes actively producing reactive oxygen species may also exist in mitochondria. We have shown recently that Nox4, a member of the NADPH oxidase family, is localized on intracellular membranes, primarily at mitochondria, in cardiomyocytes. Mitochondrial expression of Nox4 is upregulated by cardiac stress and aging in the heart, where Nox4 could become a major source of oxidative stress. This raises an intriguing possibility that Nox4 may play an important role in mediating aging of the heart. Here we discuss the potential involvement of Nox4 in mitochondrial oxidative stress and aging in the heart.

  1. 40 CFR 90.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) Conform to the continuous NOX, CO, or CO2 sampling and analysis system to the specifications of 40 CFR... condensation at any point in the dilution system. Gaseous emission samples may be taken directly from this... requirement that condensation does not occur. The temperature measuring system (sensors and readout) must...

  2. 40 CFR 90.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) Conform to the continuous NOX, CO, or CO2 sampling and analysis system to the specifications of 40 CFR... condensation at any point in the dilution system. Gaseous emission samples may be taken directly from this... requirement that condensation does not occur. The temperature measuring system (sensors and readout) must...

  3. 40 CFR 90.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) Conform to the continuous NOX, CO, or CO2 sampling and analysis system to the specifications of 40 CFR... condensation at any point in the dilution system. Gaseous emission samples may be taken directly from this... requirement that condensation does not occur. The temperature measuring system (sensors and readout) must...

  4. 40 CFR 90.421 - Dilute gaseous exhaust sampling and analytical system description.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) Conform to the continuous NOX, CO, or CO2 sampling and analysis system to the specifications of 40 CFR... condensation at any point in the dilution system. Gaseous emission samples may be taken directly from this... requirement that condensation does not occur. The temperature measuring system (sensors and readout) must...

  5. Homocysteine-induced apoptosis in endothelial cells coincides with nuclear NOX2 and peri-nuclear NOX4 activity.

    PubMed

    Sipkens, Jessica A; Hahn, Nynke; van den Brand, Carlien S; Meischl, Christof; Cillessen, Saskia A G M; Smith, Desirée E C; Juffermans, Lynda J M; Musters, René J P; Roos, Dirk; Jakobs, Cornelis; Blom, Henk J; Smulders, Yvo M; Krijnen, Paul A J; Stehouwer, Coen D A; Rauwerda, Jan A; van Hinsbergh, Victor W M; Niessen, Hans W M

    2013-11-01

    Apoptosis of endothelial cells related to homocysteine (Hcy) has been reported in several studies. In this study, we evaluated whether reactive oxygen species (ROS)-producing signaling pathways contribute to Hcy-induced apoptosis induction, with specific emphasis on NADPH oxidases. Human umbilical vein endothelial cells were incubated with 0.01-2.5 mM Hcy. We determined the effect of Hcy on caspase-3 activity, annexin V positivity, intracellular NOX1, NOX2, NOX4, and p47(phox) expression and localization, nuclear nitrotyrosine accumulation, and mitochondrial membrane potential (ΔΨ m). Hcy induced caspase-3 activity and apoptosis; this effect was concentration dependent and maximal after 6-h exposure to 2.5 mM Hcy. It was accompanied by a significant increase in ΔΨ m. Cysteine was inactive on these parameters excluding a reactive thiol group effect. Hcy induced an increase in cellular NOX2, p47(phox), and NOX4, but not that of NOX1. 3D digital imaging microscopy followed by image deconvolution analysis showed nuclear accumulation of NOX2 and p47(phox) in endothelial cells exposed to Hcy, but not in control cells, which coincided with accumulation of nuclear nitrotyrosine residues. Furthermore, Hcy enhanced peri-nuclear localization of NOX4 coinciding with accumulation of peri-nuclear nitrotyrosine residues, a reflection of local ROS production. p47(phox) was also increased in the peri-nuclear region. The Hcy-induced increase in caspase-3 activity was prevented by DPI and apocynin, suggesting involvement of NOX activity. The data presented in this article reveal accumulation of nuclear NOX2 and peri-nuclear NOX4 accumulation as potential source of ROS production in Hcy-induced apoptosis in endothelial cells.

  6. Argus NOx/SCR report

    SciTech Connect

    2005-05-15

    This document reports on NOx units at more than 350 coal and gas-fired power plants in the USA. Formerly known as the Argus SCR Report, the data are now expanded to include other forms of NOx control, including selective non-catalytic reduction (SNCR), low NOx burners and overfire air.

  7. NRF2 Regulates Hyperoxia-induced NOX4 expression in Human Lung Endothelium: Identification of functional antioxidant response elements on NOX4 promoter

    PubMed Central

    Pendyala, Srikanth; Moitra, Jaideep; Kalari, Satish; Kleeberger, Steven R.; Zhao, Yutong; Reddy, Sekhar P.; Garcia, Joe G.N.; Natarajan, Viswanathan

    2011-01-01

    Reactive oxygen species (ROS) generated by vascular endothelial and smooth muscle cells contribute to the development and progression of vascular diseases. We have recently shown that hyperoxia enhances NADPH Oxidase 4 (NOX4) expression, which regulates lung endothelial cell migration and angiogenesis. Regulation of NOX4 is poorly understood in the vasculature. The objective of this study is to identify transcriptional factor(s) involved in regulation of endothelial NOX4. We found that hyperoxia induced NOX4 expression was markedly reduced in Nrf2-/- mice, compared to Nrf2+/+ mice. Exposure of human lung microvascular endothelial cells (HLMVECs) to hyperoxia stimulated NRF2 translocation from the cytoplasm to the nucleus and increased NOX4 expression. Knock down of NRF2 expression using a siRNA approach attenuated basal NOX4 expression; however, it enhanced superoxide/ROS generation under both normoxia and hyperoxia. In silico analysis revealed presence of at least three consensus sequences for the antioxidant response element (ARE) in the promoter region of NOX4. In transient transfections, hyperoxia stimulated NOX4promoter activity in HLMVECs, and deletion of -438 to -458 and -619 to -636 sequences markedly reduced hyperoxia-stimulated NOX4 promoter activation. ChIP analysis revealed an enhanced recruitment of NRF2 to endogenous NOX4 promoter spanning these two AREs following hyperoxic insult. Collectively, these results demonstrate, for the first time, a novel role of NRF2 in regulating hyperoxia-induced NOX4 transcription via AREs in lung endothelium. PMID:21443946

  8. DIESEL NOX CONTROL APPLICATION

    EPA Science Inventory

    The paper gives results of a project to design, develop, and demonstrate a diesel engine nitrogen oxide (NOx) and particulate matter (PM) control package that will meet the U.S. Navy's emission control requirements. (NOTE: In 1994, EPA issued a Notice for Proposed Rule Making (NP...

  9. The Endoplasmic Reticulum Chaperone Calnexin Is a NADPH Oxidase NOX4 Interacting Protein*

    PubMed Central

    Prior, Kim-Kristin; Wittig, Ilka; Leisegang, Matthias S.; Groenendyk, Jody; Weissmann, Norbert; Michalak, Marek; Jansen-Dürr, Pidder; Shah, Ajay M.; Brandes, Ralf P.

    2016-01-01

    Within the family of NADPH oxidases, NOX4 is unique as it is predominantly localized in the endoplasmic reticulum, has constitutive activity, and generates hydrogen peroxide (H2O2). We hypothesize that these features are consequences of a so far unidentified NOX4-interacting protein. Two-dimensional blue native (BN) electrophorese combined with SDS-PAGE yielded NOX4 to reside in macromolecular complexes. Interacting proteins were screened by quantitative SILAC (stable isotope labeling of amino acids in cell culture) co-immunoprecipitation (Co-IP) in HEK293 cells stably overexpressing NOX4. By this technique, several interacting proteins were identified with calnexin showing the most robust interaction. Calnexin also resided in NOX4-containing complexes as demonstrated by complexome profiling from BN-PAGE. The calnexin NOX4 interaction could be confirmed by reverse Co-IP and proximity ligation assay, whereas NOX1, NOX2, or NOX5 did not interact with calnexin. Calnexin deficiency as studied in mouse embryonic fibroblasts from calnexin−/− mice or in response to calnexin shRNA reduced cellular NOX4 protein expression and reactive oxygen species formation. Our results suggest that endogenous NOX4 forms macromolecular complexes with calnexin, which are needed for the proper maturation, processing, and function of NOX4 in the endoplasmic reticulum. PMID:26861875

  10. Lean Gasoline Engine Reductant Chemistry During Lean NOx Trap Regeneration

    SciTech Connect

    Choi, Jae-Soon; Prikhodko, Vitaly Y; Partridge Jr, William P; Parks, II, James E; Norman, Kevin M; Huff, Shean P; Chambon, Paul H; Thomas, John F

    2010-01-01

    Lean NOx Trap (LNT) catalysts can effectively reduce NOx from lean engine exhaust. Significant research for LNTs in diesel engine applications has been performed and has led to commercialization of the technology. For lean gasoline engine applications, advanced direct injection engines have led to a renewed interest in the potential for lean gasoline vehicles and, thereby, a renewed demand for lean NOx control. To understand the gasoline-based reductant chemistry during regeneration, a BMW lean gasoline vehicle has been studied on a chassis dynamometer. Exhaust samples were collected and analyzed for key reductant species such as H2, CO, NH3, and hydrocarbons during transient drive cycles. The relation of the reductant species to LNT performance will be discussed. Furthermore, the challenges of NOx storage in the lean gasoline application are reviewed.

  11. Diurnal and spatial variations of soil NOx fluxes in the northern steppe of China.

    PubMed

    Wang, Bing; Lee, Xinqing; Theng, Benny K G; Cheng, Jianzhong; Yang, Fang

    2015-06-01

    NOx emissions from biogenic sources in soils play a significant role in the gaseous loss of soil nitrogen and consequent changes in tropospheric chemistry. In order to investigate the characteristics of NOx fluxes and factors influencing these fluxes in degraded sandy grasslands in northern China, diurnal and spatial variations of NOx fluxes were measured in situ. A dynamic flux chamber method was used at eight sites with various vegetation coverages and soil types in the northern steppe of China in the summer season of 2010. Fluxes of NOx from soils with plant covers were generally higher than those in the corresponding bare vegetation-free soils, indicating that the canopy plays an important role in the exchange of NOx between soil and air. The fluxes of NOx increased in the daytime, and decreased during the nighttime, with peak emissions occurring between 12:00 and 14:00. The results of multiple linear regression analysis indicated that the diurnal variation of NOx fluxes was positively correlated with soil temperature (P<0.05) and negatively with soil moisture content (P<0.05). Based on measurement over a season, the overall variation in NOx flux was lower than that of soil nitrogen contents, suggesting that the gaseous loss of N from the grasslands of northern China was not a significant contributor to the high C/N in the northern steppe of China. The concentration of NOx emitted from soils in the region did not exceed the 1-hr National Ambient Air Quality Standard (0.25 mg/m3).

  12. H-NOX from Clostridium botulinum, like H-NOX from Thermoanaerobacter tengcongensis, Binds Oxygen but with a Less Stable Oxyferrous Heme Intermediate.

    PubMed

    Wu, Gang; Liu, Wen; Berka, Vladimir; Tsai, Ah-Lim

    2015-12-01

    Heme nitric oxide/oxygen binding protein isolated from the obligate anaerobe Clostridium botulinum (Cb H-NOX) was previously reported to bind NO with a femtomolar K(D) (Nioche, P. et al. Science 2004, 306, 1550-1553). On the other hand, no oxyferrous Cb H-NOX was observed despite full conservation of the key residues that stabilize the oxyferrous complex in the H-NOX from Thermoanaerobacter tengcongensis (Tt H-NOX) (the same study). In this study, we re-measured the kinetics/affinities of Cb H-NOX for CO, NO, and O2. K(D)(CO) for the simple one-step equilibrium binding was 1.6 × 10(-7) M. The K(D)(NO) of Cb H-NOX was 8.0 × 10(-11) M for the first six-coordinate NO complex, and the previous femtomolar K(D)(NO) was actually an apparent K(D) for its multiple-step NO binding. An oxyferrous Cb H-NOX was clearly observed with a K(D)(O2) of 5.3 × 10(-5) M, which is significantly higher than Tt H-NOX's K(D)(O2) = 4.4 × 10(-8) M. The gaseous ligand binding of Cb H-NOX provides another supportive example for the "sliding scale rule" hypothesis (Tsai, A.-L. et al. Antioxid. Redox Signal. 2012, 17, 1246-1263), and the presence of hydrogen bond donor Tyr139 in Cb H-NOX selectively enhanced its affinity for oxygen.

  13. H-NOX from Clostridium botulinum, like H-NOX from Thermoanaerobacter tengcongensis, Binds Oxygen but with a Less Stable Oxyferrous Heme Intermediate.

    PubMed

    Wu, Gang; Liu, Wen; Berka, Vladimir; Tsai, Ah-Lim

    2015-12-01

    Heme nitric oxide/oxygen binding protein isolated from the obligate anaerobe Clostridium botulinum (Cb H-NOX) was previously reported to bind NO with a femtomolar K(D) (Nioche, P. et al. Science 2004, 306, 1550-1553). On the other hand, no oxyferrous Cb H-NOX was observed despite full conservation of the key residues that stabilize the oxyferrous complex in the H-NOX from Thermoanaerobacter tengcongensis (Tt H-NOX) (the same study). In this study, we re-measured the kinetics/affinities of Cb H-NOX for CO, NO, and O2. K(D)(CO) for the simple one-step equilibrium binding was 1.6 × 10(-7) M. The K(D)(NO) of Cb H-NOX was 8.0 × 10(-11) M for the first six-coordinate NO complex, and the previous femtomolar K(D)(NO) was actually an apparent K(D) for its multiple-step NO binding. An oxyferrous Cb H-NOX was clearly observed with a K(D)(O2) of 5.3 × 10(-5) M, which is significantly higher than Tt H-NOX's K(D)(O2) = 4.4 × 10(-8) M. The gaseous ligand binding of Cb H-NOX provides another supportive example for the "sliding scale rule" hypothesis (Tsai, A.-L. et al. Antioxid. Redox Signal. 2012, 17, 1246-1263), and the presence of hydrogen bond donor Tyr139 in Cb H-NOX selectively enhanced its affinity for oxygen. PMID:26574914

  14. Dual nitrate isotopes in dry deposition: Utility for partitioning NOx source contributions to landscape nitrogen deposition

    NASA Astrophysics Data System (ADS)

    Elliott, E. M.; Kendall, C.; Boyer, E. W.; Burns, D. A.; Lear, G. G.; Golden, H. E.; Harlin, K.; Bytnerowicz, A.; Butler, T. J.; Glatz, R.

    2009-12-01

    Dry deposition is a major component of total atmospheric nitrogen deposition and thus an important source of bioavailable nitrogen to ecosystems. However, relative to wet deposition, less is known regarding the sources and spatial variability of dry deposition. This is in part due to difficulty in measuring dry deposition and associated deposition velocities. Passive sampling techniques offer potential for improving our understanding of the spatial distribution and sources of gaseous and aerosol N species, referred to here as dry deposition. We report dual nitrate isotopic composition (δ15N and δ18O) in actively collected dry and wet deposition across the high-deposition region of Ohio, New York, and Pennsylvania. We also present results from initial tests to examine the efficacy of using passive nitric acid collectors as a collection medium for isotopic analysis at a site in New York. Isotopic values in actively collected dry deposition, including particulate nitrate and gaseous nitric acid, are compared with those in wet nitrate deposition and surrounding NOx emission sources. δ15N values in dry and wet fractions are highest at the westernmost sites and lowest at the easternmost sites, and stationary source NOx emissions (e.g., power plants and incinerators) appear to be the primary control on δ15N spatial variability. In contrast, δ18O values show a less consistent spatial pattern in dry deposition. Both δ15N and δ18O show strong seasonality, with higher values in winter than summer. Seasonal variations in stationary source NOx emissions appear to be the most likely explanation for seasonal variations in δ15N, whereas seasonal variations in air temperature and solar radiation indicate variable chemical oxidation pathways control δ18O patterns. Additionally, we demonstrate the utility of passive samplers for collecting the nitric acid (HNO3) component of dry deposition suitable for isotopic analysis. We observe slight differences in δ15N-HNO3 values

  15. Growth of bulk AlN single crystals with low oxygen content taking into account thermal and kinetic effects of oxygen-related gaseous species

    NASA Astrophysics Data System (ADS)

    Guguschev, C.; Dittmar, A.; Moukhina, E.; Hartmann, C.; Golka, S.; Wollweber, J.; Bickermann, M.; Fornari, R.

    2012-12-01

    Kinetic models in the system Al-N-O-C-H are useful to predict the time- and temperature-dependent influences of oxygen related species on aluminum nitride (AlN) bulk crystal growth by the sublimation-recondensation (also known as physical vapor transport, PVT) method. The transient oxygen incorporation is modeled based on non-linear regression analyses of experimental mass spectrometric data performed at conditions comparable to those of PVT crystal growth, and can be calculated for any user-specified temperature program. The results are in good qualitative agreement with SIMS measurements taken at several positions along the growth direction of a seeded isometric aluminum nitride crystal. By optimizing growth set-up geometry, source purification process, and growth parameters, the impurity content for the grown crystals decreases significantly to values of 6 ppm, 15 ppm, and 30 ppm for O, Si, and C, respectively, 2.5 mm above the AlN seed-crystal interface.

  16. Gaseous diffusion system

    DOEpatents

    Garrett, George A.; Shacter, John

    1978-01-01

    1. A gaseous diffusion system comprising a plurality of diffusers connected in cascade to form a series of stages, each of said diffusers having a porous partition dividing it into a high pressure chamber and a low pressure chamber, and means for combining a portion of the enriched gas from a succeeding stage with a portion of the enriched gas from the low pressure chamber of each stage and feeding it into one extremity of the high pressure chamber thereof.

  17. GASEOUS DISPOSAL PROCESS

    DOEpatents

    Ryan, R.F.; Thomasson, F.R.; Hicks, J.H.

    1963-01-22

    A method is described of removing gaseous radioactive Xe and Kr from water containing O. The method consists in stripping the gases from the water stream by means of H flowing countercurrently to the stream. The gases are then heated in a deoxo bed to remove O. The carrier gas is next cooled and passed over a charcoal adsorbent bed maintained at a temperature of about --280 deg F to remove the Xe and Kr. (AEC)

  18. Modeling of diffusion of plutonium in other metals and of gaseous species in plutonium-based systems. 1998 annual progress report

    SciTech Connect

    Cooper, B.R.; Fernando, G.W.

    1998-06-01

    'The problem being addressed is to establish standards for storage conditions for containers (e.g. stainless steel containers) meant to hold nuclear waste for long periods of time, e.g. fifty years, such as to ensure the integrity of the containers without being excessively conservative, i.e., being unnecessarily costly. Allowable storage temperature is an important parameter for the standards. Diffusion processes are central to certain processes that initiate corrosion of the containers or that lead to the release of gases increasing pressure that can rupture the container. The scientific goals of this project are: (1) to predict diffusion constants on an ab initio basis, i.e. diffusion distances in specified time at specified temperature, for atomic species from plutonium-based waste materials into storage container materials such as stainless steel or vice versa, (2) to predict the time development at specified temperature of complex diffusion processes in plutonium-based oxide type waste materials in the presence of water vapor such that gases may be released within a container. This predictive ability will help to provide information relevant to setting standards for waste container vessels and storage conditions. This project was initiated on September 15, 1997, so that this summary reports progress after about 2/3 of the first year of a three-year project.'

  19. Transcriptional regulation of NADPH oxidase isoforms, Nox1 and Nox4, by nuclear factor-{kappa}B in human aortic smooth muscle cells

    SciTech Connect

    Manea, Adrian; Tanase, Laurentia I.; Raicu, Monica; Simionescu, Maya

    2010-06-11

    Inflammation-induced changes in the activity and expression of NADPH oxidases (Nox) play a key role in atherogenesis. The molecular mechanisms of Nox regulation are scantily elucidated. Since nuclear factor-{kappa}B (NF-{kappa}B) controls the expression of many genes associated to inflammation-related diseases, in this study we have investigated the role of NF-{kappa}B signaling in the regulation of Nox1 and Nox4 transcription in human aortic smooth muscle cells (SMCs). Cultured cells were exposed to tumor necrosis factor-{alpha} (TNF{alpha}), a potent inducer of both Nox and NF-{kappa}B, up to 24 h. Lucigenin-enhanced chemiluminescence and dichlorofluorescein assays, real-time polymerase chain reaction, and Western blot analysis showed that inhibition of NF-{kappa}B pathway reduced significantly the TNF{alpha}-dependent up-regulation of Nox-derived reactive oxygen species production, Nox1 and Nox4 expression. In silico analysis indicated the existence of typical NF-{kappa}B elements in the promoters of Nox1 and Nox4. Transient overexpression of p65/NF-{kappa}B significantly increased the promoter activities of both isoforms. Physical interaction of p65/NF-{kappa}B proteins with the predicted sites was demonstrated by chromatin immunoprecipitation assay. These findings demonstrate that NF-{kappa}B is an essential regulator of Nox1- and Nox4-containing NADPH oxidase in SMCs. Elucidation of the complex relationships between NF-{kappa}B and Nox enzymes may lead to a novel pharmacological strategy to reduce both inflammation and oxidative stress in atherosclerosis and its associated complications.

  20. Transcriptional regulation of NADPH oxidase isoforms, Nox1 and Nox4, by nuclear factor-kappaB in human aortic smooth muscle cells.

    PubMed

    Manea, Adrian; Tanase, Laurentia I; Raicu, Monica; Simionescu, Maya

    2010-06-11

    Inflammation-induced changes in the activity and expression of NADPH oxidases (Nox) play a key role in atherogenesis. The molecular mechanisms of Nox regulation are scantily elucidated. Since nuclear factor-kappaB (NF-kappaB) controls the expression of many genes associated to inflammation-related diseases, in this study we have investigated the role of NF-kappaB signaling in the regulation of Nox1 and Nox4 transcription in human aortic smooth muscle cells (SMCs). Cultured cells were exposed to tumor necrosis factor-alpha (TNFalpha), a potent inducer of both Nox and NF-kappaB, up to 24h. Lucigenin-enhanced chemiluminescence and dichlorofluorescein assays, real-time polymerase chain reaction, and Western blot analysis showed that inhibition of NF-kappaB pathway reduced significantly the TNFalpha-dependent up-regulation of Nox-derived reactive oxygen species production, Nox1 and Nox4 expression. In silico analysis indicated the existence of typical NF-kappaB elements in the promoters of Nox1 and Nox4. Transient overexpression of p65/NF-kappaB significantly increased the promoter activities of both isoforms. Physical interaction of p65/NF-kappaB proteins with the predicted sites was demonstrated by chromatin immunoprecipitation assay. These findings demonstrate that NF-kappaB is an essential regulator of Nox1- and Nox4-containing NADPH oxidase in SMCs. Elucidation of the complex relationships between NF-kappaB and Nox enzymes may lead to a novel pharmacological strategy to reduce both inflammation and oxidative stress in atherosclerosis and its associated complications. PMID:20457132

  1. Gaseous Fuel Injection Modeling using a Gaseous Sphere Injection Methodology

    SciTech Connect

    Hessel, R P; Aceves, S M; Flowers, D L

    2006-03-06

    The growing interest in gaseous fuels (hydrogen and natural gas) for internal combustion engines calls for the development of computer models for simulation of gaseous fuel injection, air entrainment and the ensuing combustion. This paper introduces a new method for modeling the injection and air entrainment processes for gaseous fuels. The model uses a gaseous sphere injection methodology, similar to liquid droplet in injection techniques used for liquid fuel injection. In this paper, the model concept is introduced and model results are compared with correctly- and under-expanded experimental data.

  2. Downhole gaseous liquid flow agitator

    SciTech Connect

    Kamilos, N.; Kennedy, D.D.; Lederhos, L.J. Jr.

    1989-03-14

    An apparatus is described for agitating and mixing of a gaseous phase and a liquid phase comprising: a first tube having non-blocking internal threads within the first tube to agitate a liquid phase adhering thereto with a gaseous phase passing therethrough, whereby a uniform gaseous phase and liquid phase mixture is formed; and a second tube connected to an end of the first tube having non-blocking internal threads of opposite handedness.

  3. LOW NOX BURNER DEVELOPMENT

    SciTech Connect

    KRISHNA,C.R.; BUTCHER,T.

    2004-09-30

    The objective of the task is to develop concepts for ultra low NOx burners. One approach that has been tested previously uses internal recirculation of hot gases and the objective was to how to implement variable recirculation rates during burner operation. The second approach was to use fuel oil aerosolization (vaporization) and combustion in a porous medium in a manner similar to gas-fired radiant burners. This task is trying the second approach with the use of a somewhat novel, prototype system for aerosolization of the liquid fuel.

  4. Nitric Oxide-Sensing H-NOX Proteins Govern Bacterial Communal Behavior

    PubMed Central

    Plate, Lars; Marletta, Michael A.

    2013-01-01

    Heme-Nitric oxide/Oxygen binding (H-NOX) domains function as sensors for the gaseous signaling agent nitric oxide (NO) in eukaryotes and bacteria. Mammalian NO signaling is well characterized and involves the H-NOX domain of soluble guanylate cyclase. In bacteria, H-NOX proteins interact with bacterial signaling proteins in two-component signaling systems or in cyclic-di-GMP metabolism. Characterization of several downstream signaling processes has shown that bacterial H-NOX proteins share a common role in controlling important bacterial communal behaviors in response to NO. The H-NOX pathways regulate motility, biofilm formation, quorum sensing, and symbiosis. Here, we review the latest structural and mechanistic studies that have elucidated how H-NOX domains selectively bind NO and transduce ligand binding into conformational changes that modulate activity of signaling partners. Furthermore, we summarize the recent advances in understanding the physiological function and biochemical details of the H-NOX signaling pathways. PMID:24113192

  5. THE ACID RAIN NOX PROGRAM

    EPA Science Inventory

    Between 350,000 and 400,000 tons of annual NOx emissions have been eliminated as a result of Phase I of the Acid Rain NOx Program. As expected. the utilities have chosen emissions averaging as the primary compliance option. This reflects that, in general, NO x reductions have ...

  6. Don't NOx Texas

    SciTech Connect

    Mathis, J.D.; Lachowicz, Y.

    2005-07-01

    Modifications to boiler combustion systems allow Fayette Power Projects units 1 and 2 to meet new NOx emissions limits east of La Grange in Eastern Texas. The article describes modifications executed by Alstom in 2004 which attained an overall reduction in NOx emissions of almost 69%. 4 figs., 1 tab., 1 photo.

  7. Regulation of Nox enzymes expression in vascular pathophysiology: Focusing on transcription factors and epigenetic mechanisms.

    PubMed

    Manea, Simona-Adriana; Constantin, Alina; Manda, Gina; Sasson, Shlomo; Manea, Adrian

    2015-08-01

    NADPH oxidases (Nox) represent a family of hetero-oligomeric enzymes whose exclusive biological function is the generation of reactive oxygen species (ROS). Nox-derived ROS are essential modulators of signal transduction pathways that control key physiological activities such as cell growth, proliferation, migration, differentiation, and apoptosis, immune responses, and biochemical pathways. Enhanced formation of Nox-derived ROS, which is generally associated with the up-regulation of different Nox subtypes, has been established in various pathologies, namely cardiovascular diseases, diabetes, obesity, cancer, and neurodegeneration. The detrimental effects of Nox-derived ROS are related to alterations in cell signalling and/or direct irreversible oxidative damage of nucleic acids, proteins, carbohydrates, and lipids. Thus, understanding of transcriptional regulation mechanisms of Nox enzymes have been extensively investigated in an attempt to find ways to counteract the excessive formation of Nox-derived ROS in various pathological states. Despite the numerous existing data, the molecular pathways responsible for Nox up-regulation are not completely understood. This review article summarizes some of the recent advances and concepts related to the regulation of Nox expression in the vascular pathophysiology. It highlights the role of transcription factors and epigenetic mechanisms in this process. Identification of the signalling molecules involved in Nox up-regulation, which is associated with the onset and development of cardiovascular dysfunction may contribute to the development of novel strategies for the treatment of cardiovascular diseases.

  8. Tribology in Gaseous Hydrogen

    NASA Astrophysics Data System (ADS)

    Sawae, Yoshinori; Sugimura, Joich

    Hydrogen is expected as a clean and renewable energy carrier for future environment-friendly society. Many machine elements in hydrogen energy systems should be operating within hydrogen gas and tribological behavior, such as friction and wear, of bearings and seals are affected by the hydrogen environment through some interactions between material surfaces and gaseous hydrogen, i.e., physisorption of hydrogen molecules and following chemisorptions of dissociated atoms on metal surfaces, formation of metal hydride and reduction of metal oxide layer by hydrogen atoms diffused into bulk. Therefore, friction and wear characteristics of tribomaterials in the hydrogen environment should be appropriately understood to establish a design guideline for reliable hydrogen utilizing systems. This paper reviews the current knowledge about the effect of hydrogen on friction and wear of materials, and then describes our recent progress of hydrogen research in the tribology field.

  9. NOX1 mediates chemoresistance via HIF1α/MDR1 pathway in gallbladder cancer.

    PubMed

    Zhan, Ming; Wang, Hui; Chen, Tao; Chen, Wei; Yang, Linhua; He, Min; Xu, Sunwang; Wang, Jian

    NADPH oxidase 1 (NOX1) plays a key role in tumorigenesis and metastasis through generating reactive oxygen species (ROS), an important intracellular signaling molecule. However, how it is expressed in gallbladder cancer (GBC) tissue sample and whether it associates with GBC chemoresistance have never been investigated. Our study analyzed the relationship between NOX1 expression and cisplatin-sensitivity both in vivo and in vitro. We found that reduced NOX1 expression promoted cisplatin efficiency in GBC-SD cells, whereas overexpression of which potentially inhibited the sensitivity of cisplatin in SGC-996 cells. Further study into the mechanism we found that increased NOX1 expression elevated intracellular ROS levels, which then activated HIF-1α/MDR1 pathway. These findings established NOX1 a novel accelerant of chemoresistance in GBC, and NOX1-targeted therapeutics might be exploited as a strategy for increasing the efficacy of cisplatin treatment.

  10. NOX1 mediates chemoresistance via HIF1α/MDR1 pathway in gallbladder cancer.

    PubMed

    Zhan, Ming; Wang, Hui; Chen, Tao; Chen, Wei; Yang, Linhua; He, Min; Xu, Sunwang; Wang, Jian

    NADPH oxidase 1 (NOX1) plays a key role in tumorigenesis and metastasis through generating reactive oxygen species (ROS), an important intracellular signaling molecule. However, how it is expressed in gallbladder cancer (GBC) tissue sample and whether it associates with GBC chemoresistance have never been investigated. Our study analyzed the relationship between NOX1 expression and cisplatin-sensitivity both in vivo and in vitro. We found that reduced NOX1 expression promoted cisplatin efficiency in GBC-SD cells, whereas overexpression of which potentially inhibited the sensitivity of cisplatin in SGC-996 cells. Further study into the mechanism we found that increased NOX1 expression elevated intracellular ROS levels, which then activated HIF-1α/MDR1 pathway. These findings established NOX1 a novel accelerant of chemoresistance in GBC, and NOX1-targeted therapeutics might be exploited as a strategy for increasing the efficacy of cisplatin treatment. PMID:26545779

  11. Transport versus energetic particle precipitation: Northern polar stratospheric NOx and ozone in January-March 2012

    NASA Astrophysics Data System (ADS)

    Päivärinta, S.-M.; Verronen, P. T.; Funke, B.; Gardini, A.; Seppälä, A.; Andersson, M. E.

    2016-05-01

    In early 2012, a strong sudden stratospheric warming (SSW) took place, accompanied by several medium-scale solar proton events (SPEs). Here we use a chemistry transport model (CTM) in order to assess the relative contributions of (1) intensified downward transport of odd nitrogen (NOx) and (2) in situ production of NOx by protons, on stratospheric NOx and ozone during January-March 2012. The CTM is constrained by an upper boundary condition for reactive nitrogen (NOy) species, based on satellite observations from Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board Envisat, and includes a new parameterization of the SPE-caused effects on NOy and odd hydrogen (HOx) species. We found that the amount of NOx increases due to both transport and in situ production effects, the intensified descent of NOx dominating the middle and upper stratospheric impact. The model results indicate NOx enhancements of 120-3300% (5-48 ppbv) between 38 and 50 km, caused by the transport of mesosphere/lower thermosphere NOx down to the stratosphere following the SSW. The SPEs increase NOx by up to 820-1200% (14-21 ppbv) at 33 to 50 km. The effect on the stratospheric ozone is larger following the downward transport of NOx than during and after the SPEs. The model predicts ozone losses of up to 17% and 9% at around 40 km due to transport and SPE effects, respectively.

  12. NOx analyser interefence from alkenes

    NASA Astrophysics Data System (ADS)

    Bloss, W. J.; Alam, M. S.; Lee, J. D.; Vazquez, M.; Munoz, A.; Rodenas, M.

    2012-04-01

    Nitrogen oxides (NO and NO2, collectively NOx) are critical intermediates in atmospheric chemistry. NOx abundance controls the levels of the primary atmospheric oxidants OH, NO3 and O3, and regulates the ozone production which results from the degradation of volatile organic compounds. NOx are also atmospheric pollutants in their own right, and NO2 is commonly included in air quality objectives and regulations. In addition to their role in controlling ozone formation, NOx levels affect the production of other pollutants such as the lachrymator PAN, and the nitrate component of secondary aerosol particles. Consequently, accurate measurement of nitrogen oxides in the atmosphere is of major importance for understanding our atmosphere. The most widely employed approach for the measurement of NOx is chemiluminescent detection of NO2* from the NO + O3 reaction, combined with NO2 reduction by either a heated catalyst or photoconvertor. The reaction between alkenes and ozone is also chemiluminescent; therefore alkenes may contribute to the measured NOx signal, depending upon the instrumental background subtraction cycle employed. This interference has been noted previously, and indeed the effect has been used to measure both alkenes and ozone in the atmosphere. Here we report the results of a systematic investigation of the response of a selection of NOx analysers, ranging from systems used for routine air quality monitoring to atmospheric research instrumentation, to a series of alkenes ranging from ethene to the biogenic monoterpenes, as a function of conditions (co-reactants, humidity). Experiments were performed in the European Photoreactor (EUPHORE) to ensure common calibration, a common sample for the monitors, and to unequivocally confirm the alkene (via FTIR) and NO2 (via DOAS) levels present. The instrument responses ranged from negligible levels up to 10 % depending upon the alkene present and conditions used. Such interferences may be of substantial importance

  13. 40 CFR 97.12 - Changing NOX authorized account representative and alternate NOX authorized account...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Changing NOX authorized account representative and alternate NOX authorized account representative; changes in owners and operators. 97.12... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized...

  14. 40 CFR 97.12 - Changing NOX authorized account representative and alternate NOX authorized account...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Changing NOX authorized account representative and alternate NOX authorized account representative; changes in owners and operators. 97.12... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized...

  15. 40 CFR 97.12 - Changing NOX authorized account representative and alternate NOX authorized account...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Changing NOX authorized account representative and alternate NOX authorized account representative; changes in owners and operators. 97.12... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized...

  16. 40 CFR 97.12 - Changing NOX authorized account representative and alternate NOX authorized account...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Changing NOX authorized account representative and alternate NOX authorized account representative; changes in owners and operators. 97.12... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized...

  17. 40 CFR 52.2237 - NOX RACT and NOX conformity exemption.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false NOX RACT and NOX conformity exemption... RACT and NOX conformity exemption. Approval. EPA is approving the section 182(f) oxides of nitrogen (NOX) reasonably available control technology (RACT) and NOX conformity exemption request submitted...

  18. Gaseous-fuel engine technology

    SciTech Connect

    1995-12-31

    This publication contains three distinct groups of papers covering gaseous-fuel injection and control, gaseous-fuel engine projects, and gaseous-fuel engine/vehicle applications. Contents include: ultra rapid natural gas port injection; a CNG specific fuel injector using latching solenoid technology; development of an electronically-controlled natural gas-fueled John Deere PowerTech 8.1L engine; adapting a Geo Metro to run on natural gas using fuel-injection technology; behavior of a closed loop controlled air valve type mixer on a natural gas fueled engine under transient operation; and a turbocharged lean-burn 4.3 liter natural gas engine.

  19. SOURCEBOOK: NOX CONTROL TECHNOLOGY DATA

    EPA Science Inventory

    The report, a compilation of available information on the control of nitrogen oxide (NOx) emissions from stationary sources, is provided to assist new source permitting activities by regulatory agencies. he sources covered are combustion turbines, internal combustion engines, non...

  20. NADPH Oxidases NOX-1 and NOX-2 Require the Regulatory Subunit NOR-1 To Control Cell Differentiation and Growth in Neurospora crassa▿ †

    PubMed Central

    Cano-Domínguez, Nallely; Álvarez-Delfín, Karen; Hansberg, Wilhelm; Aguirre, Jesús

    2008-01-01

    We have proposed that reactive oxygen species (ROS) play essential roles in cell differentiation. Enzymes belonging to the NADPH oxidase (NOX) family produce superoxide in a regulated manner. We have identified three distinct NOX subfamilies in the fungal kingdom and have shown that NoxA is required for sexual cell differentiation in Aspergillus nidulans. Here we show that Neurospora crassa NOX-1 elimination results in complete female sterility, decreased asexual development, and reduction of hyphal growth. The lack of NOX-2 did not affect any of these processes but led instead to the production of sexual spores that failed to germinate, even in the presence of exogenous oxidants. The elimination of NOR-1, an ortholog of the mammalian Nox2 regulatory subunit gp67phox, also caused female sterility, the production of unviable sexual spores, and a decrease in asexual development and hyphal growth. These results indicate that NOR-1 is required for NOX-1 and NOX-2 functions at different developmental stages and establish a link between NOX-generated ROS and the regulation of growth. Indeed, NOX-1 was required for the increased asexual sporulation previously observed in mutants without catalase CAT-3. We also analyzed the function of the penta-EF calcium-binding domain protein PEF-1 in N. crassa. Deletion of pef-1 resulted in increased conidiation but, in contrast to what occurs in Dictyostelium discoideum, the mutation of this peflin did not suppress the phenotypes caused by the lack of NOX-1. Our results support the role of ROS as critical cell differentiation signals and highlight a novel role for ROS in regulation of fungal growth. PMID:18567788

  1. Identification of the arsenic resistance on MoO3 doped CeO2/TiO2 catalyst for selective catalytic reduction of NOx with ammonia.

    PubMed

    Li, Xiang; Li, Xiansheng; Li, Junhua; Hao, Jiming

    2016-11-15

    Arsenic resistance on MoO3 doped CeO2/TiO2 catalysts for selective catalytic reduction of NOx with NH3 (NH3-SCR) is investigated. It is found that the activity loss of CeO2-MoO3/TiO2 caused by As oxide is obvious less than that of CeO2/TiO2 catalysts. The fresh and poisoned catalysts are compared and analyzed using XRD, Raman, XPS, H2-TPR and in situ DRIFTS. The results manifest that the introduction of arsenic oxide to CeO2/TiO2 catalyst not only weakens BET surface area, surface acid sites and adsorbed NOx species, but also destroy the redox circle of Ce(4+) to Ce(3+) because of interaction between Ce and As. When MoO3 is added into CeO2/TiO2 system, the main SCR reaction path are found to be changed from the reaction between coordinated NH3 and ad-NOx species to that between an amide and gaseous NO. Additionally, for CeO2-MoO3/TiO2 catalyst, As toxic effect on active sites CeO2 can be released because of stronger As-Mo interaction. Moreover, not only are the reactable Brønsted and Lewis acid sites partly restored, but the cycle of Ce(4+) to Ce(3+) can also be free to some extent. PMID:27474851

  2. Quinone compounds regulate the level of ROS production by the NADPH oxidase Nox4.

    PubMed

    Nguyen, Minh Vu Chuong; Lardy, Bernard; Rousset, Francis; Hazane-Puch, Florence; Zhang, Leilei; Trocmé, Candice; Serrander, Lena; Krause, Karl-Heinz; Morel, Françoise

    2013-06-01

    NADPH oxidase Nox4 is expressed in a wide range of tissues and plays a role in cellular signaling by providing reactive oxygen species (ROS) as intracellular messengers. Nox4 oxidase activity is thought to be constitutive and regulated at the transcriptional level; however, we challenge this point of view and suggest that specific quinone derivatives could modulate this activity. In fact, we demonstrated a significant stimulation of Nox4 activity by 4 quinone derivatives (AA-861, tBuBHQ, tBuBQ, and duroquinone) observed in 3 different cellular models, HEK293E, T-REx™, and chondrocyte cell lines. Our results indicate that the effect is specific toward Nox4 versus Nox2. Furthermore, we showed that NAD(P)H:quinone oxidoreductase (NQO1) may participate in this stimulation. Interestingly, Nox4 activity is also stimulated by reducing agents that possibly act by reducing the disulfide bridge (Cys226, Cys270) located in the extracellular E-loop of Nox4. Such model of Nox4 activity regulation could provide new insight into the understanding of the molecular mechanism of the electron transfer through the enzyme, i.e., its potential redox regulation, and could also define new therapeutic targets in diseases in which quinones and Nox4 are implicated. PMID:23583257

  3. Gaseous Emissions from Wastewater Facilities.

    PubMed

    Koh, Sock-Hoon; Shaw, Andrew R

    2016-10-01

    A review of the literature published in 2015 on topics relating to gaseous emissions from wastewater facilities is presented. This review is divided into the following sections: odorant emissions from wastewater treatment plants (WWTPs); greenhouse gas (GHG) emissions from WWTPs; gaseous emissions from wastewater collection systems; physiochemical odor/emissions control methods; biological odor/emissions control methods; odor characterization/monitoring; and odor impacts/ risk assessments. PMID:27620089

  4. The NADPH Oxidase Subunit NOX4 Is a New Target Gene of the Hypoxia-inducible Factor-1

    PubMed Central

    Diebold, Isabel; Petry, Andreas; Hess, John

    2010-01-01

    NADPH oxidases are important sources of reactive oxygen species (ROS), possibly contributing to various disorders associated with enhanced proliferation. NOX4 appears to be involved in vascular signaling and may contribute to the response to hypoxia. However, the exact mechanisms controlling NOX4 levels under hypoxia are not resolved. We found that hypoxia rapidly enhanced NOX4 mRNA and protein levels in pulmonary artery smooth-muscle cells (PASMCs) as well as in pulmonary vessels from mice exposed to hypoxia. This response was dependent on the hypoxia-inducible transcription factor HIF-1α because overexpression of HIF-1α increased NOX4 expression, whereas HIF-1α depletion prevented this response. Mutation of a putative hypoxia-responsive element in the NOX4 promoter abolished hypoxic and HIF-1α–induced activation of the NOX4 promoter. Chromatin immunoprecipitation confirmed HIF-1α binding to the NOX4 gene. Induction of NOX4 by HIF-1α contributed to maintain ROS levels after hypoxia and hypoxia-induced proliferation of PASMCs. These findings show that NOX4 is a new target gene of HIF-1α involved in the response to hypoxia. Together with our previous findings that NOX4 mediates HIF-1α induction under normoxia, these data suggest an important role of the signaling axis between NOX4 and HIF-1α in various cardiovascular disorders under hypoxic and also nonhypoxic conditions. PMID:20427574

  5. Simulating Isotope Enrichment by Gaseous Diffusion

    NASA Astrophysics Data System (ADS)

    Reed, Cameron

    2015-04-01

    A desktop-computer simulation of isotope enrichment by gaseous diffusion has been developed. The simulation incorporates two non-interacting point-mass species whose members pass through a cascade of cells containing porous membranes and retain constant speeds as they reflect off the walls of the cells and the spaces between holes in the membranes. A particular feature is periodic forward recycling of enriched material to cells further along the cascade along with simultaneous return of depleted material to preceding cells. The number of particles, the mass ratio, the initial fractional abundance of the lighter species, and the time between recycling operations can be chosen by the user. The simulation is simple enough to be understood on the basis of two-dimensional kinematics, and demonstrates that the fractional abundance of the lighter-isotope species increases along the cascade. The logic of the simulation will be described and results of some typical runs will be presented and discussed.

  6. Determination of non-gaseous and gaseous mercury fractions in unused fluorescent lamps: a study of different lamp types.

    PubMed

    Figi, Renato; Nagel, Oliver; Schreiner, Claudia; Hagendorfer, Harald

    2015-03-01

    Since incandescent light bulbs have been phased out in the European Union from 2009, the use of fluorescent lamps has drastically increased as a reliable, more energy-efficient and cost-effective alternative. State-of-the-art fluorescent lamps are dependent on mercury/mercury alloys, posing a risk for the consumer and the environment, and appropriate waste management is challenging. Consequently analytical methods to determine possible mercury species (non-gaseous/gaseous) in these lamps are of need. Here, a straightforward and wet-chemistry-based analytical strategy for the determination of gaseous and non-gaseous mercury in commercially available fluorescent lamps is presented. It can be adapted in any analytical laboratory, without or with only minimum modifications of already installed equipment. The analytical figures of merit, as well as application of the method to a series of commercially available fluorescent lamps, are presented. Out of 14 analysed and commercially available lamp types, results from this study indicate that only one contains a slightly higher amount of mercury than set by the legislative force. In all new lamps the amount of gaseous mercury is negligible compared with the non-gaseous fraction (88%-99% of total mercury). PMID:25698790

  7. Determination of non-gaseous and gaseous mercury fractions in unused fluorescent lamps: a study of different lamp types.

    PubMed

    Figi, Renato; Nagel, Oliver; Schreiner, Claudia; Hagendorfer, Harald

    2015-03-01

    Since incandescent light bulbs have been phased out in the European Union from 2009, the use of fluorescent lamps has drastically increased as a reliable, more energy-efficient and cost-effective alternative. State-of-the-art fluorescent lamps are dependent on mercury/mercury alloys, posing a risk for the consumer and the environment, and appropriate waste management is challenging. Consequently analytical methods to determine possible mercury species (non-gaseous/gaseous) in these lamps are of need. Here, a straightforward and wet-chemistry-based analytical strategy for the determination of gaseous and non-gaseous mercury in commercially available fluorescent lamps is presented. It can be adapted in any analytical laboratory, without or with only minimum modifications of already installed equipment. The analytical figures of merit, as well as application of the method to a series of commercially available fluorescent lamps, are presented. Out of 14 analysed and commercially available lamp types, results from this study indicate that only one contains a slightly higher amount of mercury than set by the legislative force. In all new lamps the amount of gaseous mercury is negligible compared with the non-gaseous fraction (88%-99% of total mercury).

  8. NOX5-L can stimulate proliferation and apoptosis depending on its levels and cellular context, determining cancer cell susceptibility to cisplatin

    PubMed Central

    Kwon, Eun-Soo; Lim, Jae Cheong; Park, Sung Sup; Kwon, Ki-Sun

    2015-01-01

    The NADPH oxidase, NOX5, is known to stimulate cell proliferation in some cancers by generating reactive oxygen species (ROS). We show here that the long form of NOX5 (NOX5-L) also promotes cell death, and thus determines the balance of proliferation and death, in skin, breast and lung cancer cells. Moderate expression of NOX5-L induced cell proliferation accompanied by AKT and ERK phosphorylation, whereas an increase in NOX5-L above a certain threshold promoted cancer cell death accompanied by caspase-3 activation. Notably, cisplatin treatment increased NOX5-L levels through CREB activation and enhanced NOX5-L activity through augmentation of Ca2+ release and c-Abl expression, ultimately triggering ROS-mediated cancer cell death—a distinct pathway absent in normal cells. These results indicate that NOX5-L determines cellular responses in a concentration- and context-dependent manner. PMID:26513170

  9. Gaseous iodine monitoring in Europe after the Fukushima accident

    NASA Astrophysics Data System (ADS)

    Masson, Olivier; de Vismes-Ott, Anne; Manificat, Guillaume; Gurriaran, Rodolfo; Debayle, Christophe

    2014-05-01

    After the Fukushima accident and following the worldwide dispersion of contaminated air masses, many monitoring networks have reported airborne levels of emitted radionuclides, namely and mainly cesium isotopes and iodine 131. Most of the values focused on the particulate fraction (i.e. radionuclide-labeled aerosols) and were dedicated to cesium 137, cesium 134 and iodine 131. Iodine-131 was also found under gaseous form that accounted for most part of the total (gaseous + particulate)I-131 throughout the world. This gaseous predominance was also noticed after the Chernobyl accident despite differences in the type of accident. This predominance is due to the high iodine volatility and also by a rather low transfer from the gaseous form to the particulate one by adsorption on ambient airborne particles. Paradoxically, the number of gaseous determinations was rather low compared to the magnitude of data related to the particulate form (around 10 percent). Routine monitoring of airborne radionuclides species have been extensively based on aerosol sampling for decades as this allows the long term characterization of trace levels of remnant anthropogenic radionuclides. Moreover the capability of gaseous sampler equipped with activated charcoal to allow the quantification of 131I gaseous at trace level is limited by the contact time required for the sorption of iodine on the sorbent and thus by the low acceptable flow rate (usually between 3 and 5 m3/h, exceptionally 12 m3/h). In this context and despite the fact that airborne level outside Japan were of no concern for public health, this contribute to the lack of information on the actual levels of gaseous iodine. Other incidents involving iodine determination in the air have been reported in Europe in 2011 and 2012 without any relation with the Fukushima accident. For the same reason as previously mentioned, mainly, if not only, the particulate form was reported whereas it can be supposed that the predominant form was

  10. Nox NADPH Oxidases and the Endoplasmic Reticulum

    PubMed Central

    Araujo, Thaís L.S.; Abrahão, Thalita B.

    2014-01-01

    Abstract Significance: Understanding isoform- and context-specific subcellular Nox reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase compartmentalization allows relevant functional inferences. This review addresses the interplay between Nox NADPH oxidases and the endoplasmic reticulum (ER), an increasingly evident player in redox pathophysiology given its role in redox protein folding and stress responses. Recent Advances: Catalytic/regulatory transmembrane subunits are synthesized in the ER and their processing includes folding, N-glycosylation, heme insertion, p22phox heterodimerization, as shown for phagocyte Nox2. Dual oxidase (Duox) maturation also involves the regulation by ER-resident Duoxa2. The ER is the activation site for some isoforms, typically Nox4, but potentially other isoforms. Such location influences redox/Nox-mediated calcium signaling regulation via ER targets, such as sarcoendoplasmic reticulum calcium ATPase (SERCA). Growing evidence suggests that Noxes are integral signaling elements of the unfolded protein response during ER stress, with Nox4 playing a dual prosurvival/proapoptotic role in this setting, whereas Nox2 enhances proapoptotic signaling. ER chaperones such as protein disulfide isomerase (PDI) closely interact with Noxes. PDI supports growth factor-dependent Nox1 activation and mRNA expression, as well as migration in smooth muscle cells, and PDI overexpression induces acute spontaneous Nox activation. Critical Issues: Mechanisms of PDI effects include possible support of complex formation and RhoGTPase activation. In phagocytes, PDI supports phagocytosis, Nox activation, and redox-dependent interactions with p47phox. Together, the results implicate PDI as possible Nox organizer. Future Directions: We propose that convergence between Noxes and ER may have evolutive roots given ER-related functional contexts, which paved Nox evolution, namely calcium signaling and pathogen killing. Overall, the interplay between

  11. Aircraft NO(x) had no Unique Fingerprint on Sonex; Lightning Dominated Fresh NO(x) Sources

    NASA Technical Reports Server (NTRS)

    Thompson, A.; Sparling, L.; Kondo, Y.; Anderson, B.; Gregory, G.; Sachse, G.

    1999-01-01

    Key questions to which SONEX was directed were the following: Can aircraft corridors be detected? Is there a unique tracer for aircraft NO(x)? Can a "background" NO(x) (or NO(y) be defined? What fraction of NO(x) measured during SONEX was from aircraft? How representative was SONEX of the North Atlantic in 1997 and how typical of other years? We attempt to answer these questions through species-species correlations, probability distribution functions (PDFs), and meteorological history. There is not a unique aircraft tracer, largely due to the high variability of air mass origins and tracer ratios, which render "average" quantities meaningless. The greatest NO and NO(y) signals were associated with lightning and convective NO sources. Well-defined background CO, NO(y) and NO(y)/ozone ratio appear in subsets of two cross-track flights with subtropical origins and five flights with predominantly mid-latitude air. Forty percent of the observations on these 7 flights showed NO(y)/ozone to be above background, evidently due to unreacted NO(x). This NO(x) is a combination of aircraft, lightning and surface pollution injected by convection. The strongly subtropical signatures in SONEX observations, confirmed by pv (potential vorticity) values along flight tracks, argues for most of the unreacted NO(x) originating from lightning. Potential vorticity statistics along SONEX flight tracks in 1992-1998, and for the North Atlantic as a whole, show the SONEX meteorological environment to be representative of the North Atlantic flight corridor in the October-November period.

  12. Nox/Duox Family of NADPH Oxidases: Lessons from Knockout Mouse Models.

    PubMed

    Sirokmány, Gábor; Donkó, Ágnes; Geiszt, Miklós

    2016-04-01

    Nox/Duox NADPH oxidases are now considered the primary, regulated sources of reactive oxygen species (ROS). These enzymes are expressed in diverse cells and tissues, and their products are essential in several physiological settings. Knockout mouse models are instrumental in identifying the physiological functions of Nox/Duox enzymes as well as in exploring the impact of their pharmacological targeting on disease progression. The currently available data from experiments on knockout animals suggest that the lack of non-phagocytic Nox/Duox enzymes often modifies the course and phenotype in many disease models. Nevertheless, as illustrated by studies on Nox4-deficient animals, the absence of Nox-derived ROS can also lead to aggravated disease manifestation, reinforcing the need for a more balanced view on the role of ROS in health and disease.

  13. Is Nox4 a key regulator of the activated state of fibroblasts in systemic sclerosis?

    PubMed

    Böhm, Markus; Dosoki, Heba; Kerkhoff, Claus

    2014-09-01

    The family of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases consists of phagocytic gp91(phox) and six-related isoforms. Recent evidence indicates that the NADPH oxidase isoform Nox4 controls vascular, renal and pulmonary injury. We propose that Nox4 is an intrinsic regulator of the activated state of dermal fibroblasts in systemic sclerosis (SSc). Profibrotic cytokines on the one hand and antifibrogenic factors such as α-melanocyte-stimulating hormone on the other hand may target Nox4 as an intracellular nodal point. Via increased or decreased generation of reactive oxygen species and/or hydrogen peroxide, Nox4 could orchestrate collagen synthesis, differentiation of dermal fibroblasts into a profibrotic myofibroblast phenotype and thus dermal fibrosis. Confirmation of this hypothesis will have important consequences in our understanding of the activated state of dermal fibroblasts in SSc. Based on the availability of clinically useful Nox4 inhibitors, novel antifibrotic therapies of SSc can be envisioned. PMID:25040787

  14. NOx adsorber and method of regenerating same

    DOEpatents

    Endicott, Dennis L.; Verkiel, Maarten; Driscoll, James J.

    2007-01-30

    New technologies, such as NOx adsorber catalytic converters, are being used to meet increasingly stringent regulations on undesirable emissions, including NOx emissions. NOx adsorbers must be periodically regenerated, which requires an increased fuel consumption. The present disclosure includes a method of regenerating a NOx adsorber within a NOx adsorber catalytic converter. At least one sensor positioned downstream from the NOx adsorber senses, in the downstream exhaust, at least one of NOx, nitrous oxide and ammonia concentrations a plurality of times during a regeneration phase. The sensor is in communication with an electronic control module that includes a regeneration monitoring algorithm operable to end the regeneration phase when a time rate of change of the at least one of NOx, nitrous oxide and ammonia concentrations is after an expected plateau region begins.

  15. 40 CFR 96.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 96.52 Section 96.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX...

  16. 40 CFR 96.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 96.188 Section 96.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS...

  17. 40 CFR 96.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 96.188 Section 96.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS...

  18. 40 CFR 97.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 97.188 Section 97.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING...

  19. 40 CFR 96.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 96.52 Section 96.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX...

  20. 40 CFR 52.2237 - NOX RACT and NOX conformity exemption.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 5 2014-07-01 2014-07-01 false NOX RACT and NOX conformity exemption... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Tennessee § 52.2237 NOX RACT and NOX conformity exemption. Approval. EPA is approving the section 182(f) oxides of...

  1. 40 CFR 96.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 96.188 Section 96.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS...

  2. 40 CFR 97.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 97.188 Section 97.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING...

  3. 40 CFR 96.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 96.188 Section 96.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS...

  4. 40 CFR 96.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 96.52 Section 96.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX...

  5. 40 CFR 52.2237 - NOX RACT and NOX conformity exemption.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 5 2013-07-01 2013-07-01 false NOX RACT and NOX conformity exemption... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Tennessee § 52.2237 NOX RACT and NOX conformity exemption. Approval. EPA is approving the section 182(f) oxides of...

  6. 40 CFR 97.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 97.188 Section 97.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING...

  7. 40 CFR 97.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 97.188 Section 97.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING...

  8. 40 CFR 96.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 96.52 Section 96.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX...

  9. 40 CFR 97.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 97.188 Section 97.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING...

  10. 40 CFR 96.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 96.188 Section 96.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS...

  11. 40 CFR 52.2237 - NOX RACT and NOX conformity exemption.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Tennessee § 52.2237 NOX RACT and NOX conformity exemption. Approval. EPA is approving the section 182(f) oxides of nitrogen... 40 Protection of Environment 5 2012-07-01 2012-07-01 false NOX RACT and NOX conformity...

  12. 40 CFR 96.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 96.52 Section 96.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX...

  13. 40 CFR 52.2237 - NOX RACT and NOX conformity exemption.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Tennessee § 52.2237 NOX RACT and NOX conformity exemption. Approval. EPA is approving the section 182(f) oxides of nitrogen... 40 Protection of Environment 4 2011-07-01 2011-07-01 false NOX RACT and NOX conformity...

  14. NOx, VOCs, and meteorological conditions influencing ozone variation in Kaohsiung, Taiwan

    NASA Astrophysics Data System (ADS)

    Kuo, Y.; Yu, H.; Wang, S.; Jang, C.

    2011-12-01

    The complex process of ozone formation, its precursor compounds (volatile organic compounds (VOCs) and nitrogen oxides (NOx)) emissions, accompanying with meteorological conditions, makes ozone difficult to control. Dynamic factor analysis (DFA) and min/max autocorrelation factor analysis (MAFA) especially designed for time series data, which tolerate missing values, allow analyzing short, non-stationary multivariate time series that can contain meteorological and gaseous pollutant explanatory variables. The first min/max autocorrelation factor axis (MAF 1) is the major trend which shows regular daily fluctuation; while the second common trend of DFM is similar to it. For both episodes, temperature, relative humidity, and wind speed are highly correlated with MAF 1, indicating these meteorological conditions mainly affect the ozone variability. According to the best DFM, temperature, wind speed, and NOx in high ozone episode and temperature and NOx in the low ozone episode highly affect the ozone variability. The best DFM shows explanatory variables rather than common trends play important roles in describing ozone variation. Comparing effects of VOCs and NOx on O3 variation, ozone variation is relatively sensitive to VOCs in the low ozone episode and is relatively sensitive to NOx in high zone episode. The results of DFM and MAFA show that the ozone variations of Mei-nung stations were distinguished from other stations for both ozone episodes. The resulting dynamic factor models yielded good predictions of observed ozone series (overall coefficient of efficiency (Ceff) = 0.90 in low ozone episode and Ceff = 0.95 in the high ozone episode). In this study, DFA and NAFA provides a quantitative insight into the spatial distributions of VOCs, NOx, and meteorological conditions effects on ozone.
    Table 1. Correlations between explanatory variables and the three significant min/max autocorrelation factor (MAF) axes.

  15. Nicotinamide Adenine Dinucleotide Phosphate Oxidase (NOX) in Experimental Liver Fibrosis: GKT137831 as a Novel Potential Therapeutic Agent

    PubMed Central

    Aoyama, Tomonori; Paik, Yong-Han; Watanabe, Sumio; Laleu, Benoît; Gaggini, Francesca; Fioraso-Cartier, Laetitia; Molango, Sophie; Heitz, Freddy; Merlot, Cédric; Szyndralewiez, Cédric; Page, Patrick; Brenner, David A.

    2012-01-01

    Background & Aims NADPH oxidase (NOX) generates reactive oxygen species (ROS) in hepatic stellate cells (HSCs) during liver fibrosis. In response to fibrogenic agonists, such as angiotensin II (Ang II), the NOX1 components form an active complex including Rac1. Superoxide dismutase 1 (SOD1) interacts with the NOX-Rac1 complex to stimulate NOX activity. NOX4 is also induced in activated HSCs/myofibroblast by increased gene expression. Here, we investigate the role of an enhanced activity SOD1 G37R mutation (SODmu) and the effects of GKT137831, a dual NOX1/4 inhibitor, on HSCs and liver fibrosis. Methods To induce liver fibrosis, wild-type (WT) and SOD1mu mice were treated with carbon tetrachloride (CCl4) or bile duct ligation (BDL). Then, to address the role of NOX-SOD1-mediated ROS production in HSC activation and liver fibrosis, mice were treated with a NOX1/4 inhibitor. Fibrosis and ROS generation was assessed by histology and measurement of TBARS and NOX related genes. Primary cultured HSCs isolated from WT, SODmu, and NOX1 knock-out (KO) mice were assessed for ROS production, Rac1 activity, and NOX gene expression. Results Liver fibrosis was increased in SOD1mu mice, and ROS production and Rac1 activity were increased in SOD1mu HSCs. The NOX1/4 inhibitor GKT137831 attenuated liver fibrosis and ROS production in both SOD1mu and WT mice as well as mRNA expression of fibrotic and NOX genes. Treatment with GKT137831 suppressed ROS production and NOX and fibrotic gene expression, but not Rac1 activity, in SOD1mut and WT HSCs. Both Ang II and TGFb upregulated NOX4, but AngII required NOX1. Conclusions SOD1mu induces excessive NOX1 activation through Rac1 in HSCs, causing enhanced NOX4 upregulation, ROS generation, and liver fibrosis. Treatment targeting NOX1/4 may be a new therapy for liver fibrosis. PMID:22806357

  16. 40 CFR 97.11 - Alternate NOX authorized account representative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Alternate NOX authorized account... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized Account Representative for NOX Budget Sources § 97.11 Alternate NOX authorized...

  17. 40 CFR 97.60 - Submission of NOX allowance transfers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Submission of NOX allowance transfers... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Transfers § 97.60 Submission of NOX allowance transfers. The NOX authorized account representatives...

  18. 40 CFR 97.60 - Submission of NOX allowance transfers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Submission of NOX allowance transfers... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Transfers § 97.60 Submission of NOX allowance transfers. The NOX authorized account representatives...

  19. 40 CFR 96.60 - Submission of NOX allowance transfers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Submission of NOX allowance transfers... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Transfers § 96.60 Submission of NOX allowance transfers. The NOX...

  20. 40 CFR 97.60 - Submission of NOX allowance transfers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Submission of NOX allowance transfers... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Transfers § 97.60 Submission of NOX allowance transfers. The NOX authorized account representatives...

  1. 40 CFR 97.60 - Submission of NOX allowance transfers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Submission of NOX allowance transfers... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Transfers § 97.60 Submission of NOX allowance transfers. The NOX authorized account representatives...

  2. 40 CFR 96.60 - Submission of NOX allowance transfers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Submission of NOX allowance transfers... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Transfers § 96.60 Submission of NOX allowance transfers. The NOX...

  3. 40 CFR 96.60 - Submission of NOX allowance transfers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Submission of NOX allowance transfers... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Transfers § 96.60 Submission of NOX allowance transfers. The NOX...

  4. 40 CFR 97.11 - Alternate NOX authorized account representative.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Alternate NOX authorized account... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized Account Representative for NOX Budget Sources § 97.11 Alternate NOX authorized...

  5. 40 CFR 97.11 - Alternate NOX authorized account representative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Alternate NOX authorized account... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized Account Representative for NOX Budget Sources § 97.11 Alternate NOX authorized...

  6. 40 CFR 97.11 - Alternate NOX authorized account representative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Alternate NOX authorized account... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized Account Representative for NOX Budget Sources § 97.11 Alternate NOX authorized...

  7. 40 CFR 96.60 - Submission of NOX allowance transfers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Submission of NOX allowance transfers... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Transfers § 96.60 Submission of NOX allowance transfers. The NOX...

  8. 40 CFR 97.53 - Recordation of NOX allowance allocations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) Serial numbers for allocated NO X allowances. When allocating NOX allowances to a NOX Budget unit and... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Recordation of NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX...

  9. 40 CFR 97.60 - Submission of NOX allowance transfers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Submission of NOX allowance transfers... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Transfers § 97.60 Submission of NOX allowance transfers. The NOX authorized account representatives...

  10. 40 CFR 97.11 - Alternate NOX authorized account representative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Alternate NOX authorized account... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized Account Representative for NOX Budget Sources § 97.11 Alternate NOX authorized...

  11. 40 CFR 96.60 - Submission of NOX allowance transfers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Submission of NOX allowance transfers... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Transfers § 96.60 Submission of NOX allowance transfers. The NOX...

  12. Nox2 and p47(phox) modulate compensatory growth of primary collateral arteries.

    PubMed

    DiStasi, Matthew R; Unthank, Joseph L; Miller, Steven J

    2014-05-15

    The role of NADPH oxidase (Nox) in both the promotion and impairment of compensatory collateral growth remains controversial because the specific Nox and reactive oxygen species involved are unclear. The aim of this study was to identify the primary Nox and reactive oxygen species associated with early stage compensatory collateral growth in young, healthy animals. Ligation of the feed arteries that form primary collateral pathways in rat mesentery and mouse hindlimb was used to assess the role of Nox during collateral growth. Changes in mesenteric collateral artery Nox mRNA expression determined by real-time PCR at 1, 3, and 7 days relative to same-animal control arteries suggested a role for Nox subunits Nox2 and p47(phox). Administration of apocynin or Nox2ds-tat suppressed collateral growth in both rat and mouse models, suggesting the Nox2/p47(phox) interaction was involved. Functional significance of p47(phox) expression was assessed by evaluation of collateral growth in rats administered p47(phox) small interfering RNA and in p47(phox-/-) mice. Diameter measurements of collateral mesenteric and gracilis arteries at 7 and 14 days, respectively, indicated no significant collateral growth compared with control rats or C57BL/6 mice. Chronic polyethylene glycol-conjugated catalase administration significantly suppressed collateral development in rats and mice, implying a requirement for H2O2. Taken together, these results suggest that Nox2, modulated at least in part by p47(phox), mediates early stage compensatory collateral development via a process dependent upon peroxide generation. These results have important implications for the use of antioxidants and the development of therapies for peripheral arterial disease.

  13. A new method and application for determining the nitrogen isotopic composition of NOx

    NASA Astrophysics Data System (ADS)

    Hastings, M. G.; Miller, D. J.; Wojtal, P.; O'Connor, M.

    2015-12-01

    Atmospheric nitrogen oxides (NOx = NO + NO2) play key roles in atmospheric chemistry, air quality, and radiative forcing, and contribute to nitric acid deposition. Sources of NOx include both natural and anthropogenic emissions, which vary significantly in space and time. NOx isotopic signatures offer a potentially valuable tool to trace source impacts on atmospheric chemistry and regional acid deposition. Previous work on NOx isotopic signatures suggests large ranges in values, even from the same emission source, as well as overlapping ranges amongst different sources, making it difficult to use the isotopic composition as a quantitative tracer of source influences. These prior measurements have utilized a variety of methods for collecting the NOx as nitrate or nitrite for isotopic analysis, and testing of some of these methods (including active and passive collections) reveal inconsistencies in efficiency of collection, as well as issues related to changes in conditions such as humidity, temperature, and NOx fluxes. A recently developed method allows for accurately measuring the nitrogen isotopic composition of NOx (NOx = NO + NO2) after capturing the NOx in a potassium permanganate/sodium hydroxide solution as nitrate (Fibiger et al., Anal. Chem., 2014). The method has been thoroughly tested in the laboratory and field, and efficiently collects NO and NO2 under a variety of conditions. There are several advantages to collecting NOx actively, including the ability to collect over minutes to hourly time scales, and the ability to collect in environments with highly variable NOx sources and concentrations. Challenges include a nitrate background present in potassium permanganate (solid and liquid forms), accurately deriving ambient NOx concentrations based upon flow rate and solution concentrations above this variable background, and potential interferences from other nitrogen species. This method was designed to collect NOx in environments with very different

  14. The Role of the NADPH Oxidase NOX2 in Prion Pathogenesis

    PubMed Central

    Sorce, Silvia; Nuvolone, Mario; Keller, Annika; Falsig, Jeppe; Varol, Ahmet; Schwarz, Petra; Bieri, Monika; Budka, Herbert; Aguzzi, Adriano

    2014-01-01

    Prion infections cause neurodegeneration, which often goes along with oxidative stress. However, the cellular source of reactive oxygen species (ROS) and their pathogenetic significance are unclear. Here we analyzed the contribution of NOX2, a prominent NADPH oxidase, to prion diseases. We found that NOX2 is markedly upregulated in microglia within affected brain regions of patients with Creutzfeldt-Jakob disease (CJD). Similarly, NOX2 expression was upregulated in prion-inoculated mouse brains and in murine cerebellar organotypic cultured slices (COCS). We then removed microglia from COCS using a ganciclovir-dependent lineage ablation strategy. NOX2 became undetectable in ganciclovir-treated COCS, confirming its microglial origin. Upon challenge with prions, NOX2-deficient mice showed delayed onset of motor deficits and a modest, but significant prolongation of survival. Dihydroethidium assays demonstrated a conspicuous ROS burst at the terminal stage of disease in wild-type mice, but not in NOX2-ablated mice. Interestingly, the improved motor performance in NOX2 deficient mice was already measurable at earlier stages of the disease, between 13 and 16 weeks post-inoculation. We conclude that NOX2 is a major source of ROS in prion diseases and can affect prion pathogenesis. PMID:25502554

  15. Effects of NOX1 on fibroblastic changes of endothelial cells in radiation-induced pulmonary fibrosis

    PubMed Central

    CHOI, SEO-HYUN; KIM, MISEON; LEE, HAE-JUNE; KIM, EUN-HO; KIM, CHUN-HO; LEE, YOON-JIN

    2016-01-01

    Lung fibrosis is a major complication in radiation-induced lung damage following thoracic radiotherapy, while the underlying mechanism has remained to be elucidated. The present study performed immunofluorescence and immunoblot assays on irradiated human pulmonary artery endothelial cells (HPAECs) with or without pre-treatment with VAS2870, a novel NADPH oxidase (NOX) inhibitor, or small hairpin (sh)RNA against NOX1, -2 or -4. VAS2870 reduced the cellular reactive oxygen species content induced by 5 Gy radiation in HPAECs and inhibited phenotypic changes in fibrotic cells, including increased alpha smooth muscle actin and vimentin, and decreased CD31 and vascular endothelial cadherin expression. These fibrotic changes were significantly inhibited by treatment with NOX1 shRNA, but not by NOX2 or NOX4 shRNA. Next, the role of NOX1 in pulmonary fibrosis development was assessed in the lung tissues of C57BL/6J mice following thoracic irradiation using trichrome staining. Administration of an NOX1-specific inhibitor suppressed radiation-induced collagen deposition and fibroblastic changes in the endothelial cells (ECs) of these mice. The results suggested that radiation-induced pulmonary fibrosis may be efficiently reduced by specific inhibition of NOX1, an effect mediated by reduction of fibrotic changes of ECs. PMID:27053172

  16. Elucidating N2O Formation during the Cyclic NOx Storage and Reduction Process Using CO as a Reductant.

    PubMed

    Wang, Jun; Wang, Xiuting; Zhu, Jinxin; Wang, Jianqiang; Shen, Meiqing

    2015-07-01

    The N2O formation pathway and effect of H2O on N2O formation during the NOx storage and reduction (NSR) process using CO as a reductant were investigated over a Pt-BaO/Al2O3 catalyst. The NSR activity measurements and transient in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments were performed to evaluate N2O evolution and elucidate the N2O formation mechanism. N2O is formed in the lean, rich, and delay2 phases. In the lean phase, N2O formation is related to the reactions between surface isocyanate and gaseous NO/O2 and NO is more responsible for N2O formation than O2. Moreover, N2O production decreases with H2O because of the hydrolysis of isocyanate species. In the rich phase, the amount of N2O formation also decreases in the presence of H2O at a higher temperature because of the high reduction ability of H2 generated from the water-gas shift (WGS) reaction. During the delay2 phase, N2O is mainly formed by nitrite species reacting with Pt(0)-CO. Furthermore, the presence of H2O decreases the stability of nitrites and results in more N2O production at a low temperature.

  17. Nox2 contributes to the arterial endothelial specification of mouse induced pluripotent stem cells by upregulating Notch signaling

    PubMed Central

    Kang, Xueling; Wei, Xiangxiang; Wang, Xinhong; Jiang, Li; Niu, Cong; Zhang, Jianyi; Chen, Sifeng; Meng, Dan

    2016-01-01

    Reactive oxygen species (ROS) have a crucial role in stem-cell differentiation; however, the mechanisms by which ROS regulate the differentiation of stem cells into endothelial cells (ECs) are unknown. Here, we determine the role of ROS produced by NADPH oxidase 2 (Nox2) in the endothelial-lineage specification of mouse induced-pluripotent stem cells (miPSCs). When wild-type (WT) and Nox2-knockout (Nox2−/−) miPSCs were differentiated into ECs (miPSC-ECs), the expression of endothelial markers, arterial endothelial markers, pro-angiogenic cytokines, and Notch pathway components was suppressed in the Nox2−/− cells but increased in both WT and Nox2−/− miPSCs when Nox2 expression was upregulated. Higher levels of Nox2 expression increased Notch signaling and arterial EC differentiation, and this increase was abolished by the inhibition of ROS generation or by the silencing of Notch1 expression. Nox2 deficiency was associated with declines in the survival and angiogenic potency of miPSC-ECs, and capillary and arterial density were lower in the ischemic limbs of mice after treatment with Nox2−/− miPSC-ECs than WT miPSC-EC treatment. Taken together, these observations indicate that Nox2-mediated ROS production promotes arterial EC specification in differentiating miPSCs by activating the Notch signaling pathway and contributes to the angiogenic potency of transplanted miPSC-derived ECs. PMID:27642005

  18. BcNoxD, a putative ER protein, is a new component of the NADPH oxidase complex in Botrytis cinerea.

    PubMed

    Siegmund, Ulrike; Marschall, Robert; Tudzynski, Paul

    2015-03-01

    NADPH oxidases (Nox) are major enzymatic producer of reactive oxygen species (ROS). In fungi these multi-enzyme complexes are involved in sexual differentiation and pathogenicity. However, in contrast to mammalian systems, the composition and recruitment of the fungal Nox complexes are unresolved. Here we introduce a new Nox component, the membrane protein NoxD in the grey mold fungus Botrytis cinerea. It has high homology to the ER protein Pro41 from Sordaria macrospora, similar functions to the catalytic Nox subunit BcNoxA in differentiation and pathogenicity, and shows similarities to phagocytic p22phox. BcNoxA and BcNoxD interact with each other. Both proteins are involved in pathogenicity, fusion of conidial anastomosis tubes (CAT) and formation of sclerotia and conidia. These data support our earlier view based on localization studies, for an ER-related function of the Nox complex. We present the first evidence that some functions of the BcNoxA complex are indeed linked to the ER, while others clearly require export from the ER. PMID:25402961

  19. Nox2 contributes to the arterial endothelial specification of mouse induced pluripotent stem cells by upregulating Notch signaling.

    PubMed

    Kang, Xueling; Wei, Xiangxiang; Wang, Xinhong; Jiang, Li; Niu, Cong; Zhang, Jianyi; Chen, Sifeng; Meng, Dan

    2016-01-01

    Reactive oxygen species (ROS) have a crucial role in stem-cell differentiation; however, the mechanisms by which ROS regulate the differentiation of stem cells into endothelial cells (ECs) are unknown. Here, we determine the role of ROS produced by NADPH oxidase 2 (Nox2) in the endothelial-lineage specification of mouse induced-pluripotent stem cells (miPSCs). When wild-type (WT) and Nox2-knockout (Nox2(-/-)) miPSCs were differentiated into ECs (miPSC-ECs), the expression of endothelial markers, arterial endothelial markers, pro-angiogenic cytokines, and Notch pathway components was suppressed in the Nox2(-/-) cells but increased in both WT and Nox2(-/-) miPSCs when Nox2 expression was upregulated. Higher levels of Nox2 expression increased Notch signaling and arterial EC differentiation, and this increase was abolished by the inhibition of ROS generation or by the silencing of Notch1 expression. Nox2 deficiency was associated with declines in the survival and angiogenic potency of miPSC-ECs, and capillary and arterial density were lower in the ischemic limbs of mice after treatment with Nox2(-/-) miPSC-ECs than WT miPSC-EC treatment. Taken together, these observations indicate that Nox2-mediated ROS production promotes arterial EC specification in differentiating miPSCs by activating the Notch signaling pathway and contributes to the angiogenic potency of transplanted miPSC-derived ECs. PMID:27642005

  20. Development and integration of a scalable low NOx combustion chamber for a hydrogen-fueled aerogas turbine

    NASA Astrophysics Data System (ADS)

    Boerner, S.; Funke, H. H.-W.; Hendrick, P.; Recker, E.; Elsing, R.

    2013-03-01

    The usage of alternative fuels in aircraft industry plays an important role of current aero engine research and development processes. The micromix burning principle allows a secure and low NOx combustion of gaseous hydrogen. The combustion principle is based on the fluid phenomenon of jet in cross flow and achieves a significant lowering in NOx formation by using multiple miniaturized flames. The paper highlights the development and the integration of a combustion chamber, based on the micromix combustion principle, into an Auxiliary Power Unit (APU) GTCP 36-300 with regard to the necessary modifications on the gas turbine and on the engine controller.

  1. Turbulent diffusion of chemically reacting gaseous admixtures

    NASA Astrophysics Data System (ADS)

    Elperin, T.; Kleeorin, N.; Liberman, M.; Rogachevskii, I.

    2014-11-01

    We study turbulent diffusion of chemically reacting gaseous admixtures in a developed turbulence. In our previous study [Phys. Rev. Lett. 80, 69 (1998), 10.1103/PhysRevLett.80.69] using a path-integral approach for a delta-correlated in a time random velocity field, we demonstrated a strong modification of turbulent transport in fluid flows with chemical reactions or phase transitions. In the present study we use the spectral τ approximation that is valid for large Reynolds and Peclet numbers and show that turbulent diffusion of the reacting species can be strongly depleted by a large factor that is the ratio of turbulent and chemical times (turbulent Damköhler number). We have demonstrated that the derived theoretical dependence of a turbulent diffusion coefficient versus the turbulent Damköhler number is in good agreement with that obtained previously in the numerical modeling of a reactive front propagating in a turbulent flow and described by the Kolmogorov-Petrovskii-Piskunov-Fisher equation. We have found that turbulent cross-effects, e.g., turbulent mutual diffusion of gaseous admixtures and turbulent Dufour effect of the chemically reacting gaseous admixtures, are less sensitive to the values of stoichiometric coefficients. The mechanisms of the turbulent cross-effects differ from the molecular cross-effects known in irreversible thermodynamics. In a fully developed turbulence and at large Peclet numbers the turbulent cross-effects are much larger than the molecular ones. The obtained results are applicable also to heterogeneous phase transitions.

  2. Impact of chamber wall loss of gaseous organic compounds on secondary organic aerosol formation: explicit modeling of SOA formation from alkane and alkene oxidation

    NASA Astrophysics Data System (ADS)

    La, Y. S.; Camredon, M.; Ziemann, P. J.; Valorso, R.; Matsunaga, A.; Lannuque, V.; Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.

    2016-02-01

    Recent studies have shown that low volatility gas-phase species can be lost onto the smog chamber wall surfaces. Although this loss of organic vapors to walls could be substantial during experiments, its effect on secondary organic aerosol (SOA) formation has not been well characterized and quantified yet. Here the potential impact of chamber walls on the loss of gaseous organic species and SOA formation has been explored using the Generator for Explicit Chemistry and Kinetics of the Organics in the Atmosphere (GECKO-A) modeling tool, which explicitly represents SOA formation and gas-wall partitioning. The model was compared with 41 smog chamber experiments of SOA formation under OH oxidation of alkane and alkene series (linear, cyclic and C12-branched alkanes and terminal, internal and 2-methyl alkenes with 7 to 17 carbon atoms) under high NOx conditions. Simulated trends match observed trends within and between homologous series. The loss of organic vapors to the chamber walls is found to affect SOA yields as well as the composition of the gas and the particle phases. Simulated distributions of the species in various phases suggest that nitrates, hydroxynitrates and carbonylesters could substantially be lost onto walls. The extent of this process depends on the rate of gas-wall mass transfer, the vapor pressure of the species and the duration of the experiments. This work suggests that SOA yields inferred from chamber experiments could be underestimated up a factor of 2 due to the loss of organic vapors to chamber walls.

  3. Impact of chamber wall loss of gaseous organic compounds on secondary organic aerosol formation: explicit modeling of SOA formation from alkane and alkene oxidation

    NASA Astrophysics Data System (ADS)

    La, Y. S.; Camredon, M.; Ziemann, P. J.; Valorso, R.; Matsunaga, A.; Lannuque, V.; Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.

    2015-09-01

    Recent studies have shown that low volatility gas-phase species can be lost onto the smog chamber wall surfaces. Although this loss of organic vapors to walls could be substantial during experiments, its effect on secondary organic aerosol (SOA) formation has not been well characterized and quantified yet. Here the potential impact of chamber walls on the loss of gaseous organic species and SOA formation has been explored using the Generator for Explicit Chemistry and Kinetics of the Organics in the Atmosphere (GECKO-A) modeling tool which explicitly represents SOA formation and gas/wall partitioning. The model was compared with 41 smog chamber experiments of SOA formation under OH oxidation of alkane and alkene series (linear, cyclic and C12-branched alkanes and terminal, internal and 2-methyl alkenes with 7 to 17 carbon atoms) under high NOx conditions. Simulated trends match observed trends within and between homologous series. The loss of organic vapors to the chamber walls is found to affect SOA yields as well as the composition of the gas and the particle phases. Simulated distributions of the species in various phases suggest that nitrates, hydroxynitrates and carbonylesters could substantially be lost onto walls. The extent of this process depends on the rate of gas/wall mass transfer, the vapor pressure of the species and the duration of the experiments. This work suggests that SOA yields inferred from chamber experiments could be underestimated up to 0.35 yield unit due to the loss of organic vapors to chamber walls.

  4. Ebselen and congeners inhibit NADPH-oxidase 2 (Nox2)-dependent superoxide generation by interrupting the binding of regulatory subunits

    PubMed Central

    Smith, Susan M.E.; Min, Jaeki; Ganesh, Thota; Diebold, Becky; Kawahara, Tsukasa; Zhu, Yerun; McCoy, James; Sun, Aiming; Snyder, James P.; Fu, Haian; Du, Yuhong; Lewis, Iestyn; Lambeth, J. David

    2012-01-01

    Summary NADPH-oxidases are a primary source of reactive oxygen species (ROS), which function in normal physiology and, when overproduced, in pathophysiology. Recent studies using mice deficient in Nox2 identify this isoform as a novel target against Nox2-implicated inflammatory diseases. Nox2 activation depends on the binding of the proline rich domain of its heterodimeric partner p22phox to p47phox. A high-throughput screen that monitored this interaction via fluorescence polarization identified ebselen and several of its analogs as inhibitors. Medicinal chemistry was performed to explore structure-activity relationships and to optimize potency. Ebselen and analogs potently inhibited Nox1 and Nox2 activity but were less effective against other isoforms. Ebselen also blocked translocation of p47phox to neutrophil membranes. Thus, ebselen and its analogs represent a class of compounds that inhibit ROS generation by interrupting the assembly of Nox2-activating regulatory subunits. PMID:22726689

  5. Stabilizing a gaseous optical laser

    NASA Technical Reports Server (NTRS)

    Jauan, A.; Shimoda, K.

    1974-01-01

    Frequency of gaseous optical laser can be stabilized by sinusoidally modulating the geometry of the cavity. Fabry-Perot dielectric mirrors are mounted in two Invar blocks that are connected by four magnetorestrictive bars. Each bar has three coils to sinusoidally modulate system. Ac establishes frequency, and dc the average value; both are supplied to coil from control system.

  6. Combustion characteristics of hydrogen. Carbon monoxide based gaseous fuels

    NASA Technical Reports Server (NTRS)

    Notardonato, J. J.; White, D. J.; Kubasco, A. J.; Lecren, R. T.

    1981-01-01

    An experimental rig program was conducted with the objective of evaluating the combuston performance of a family of fuel gases based on a mixture of hydrogen and carbon monoxide. These gases, in addition to being members of a family, were also representative of those secondary fuels that could be produced from coal by various gasification schemes. In particular, simulated Winkler, Lurgi, and Blue-water low and medium energy content gases were used as fuels in the experimental combustor rig. The combustor used was originally designed as a low NOx rich-lean system for burning liquid fuels with high bound nitrogen levels. When used with the above gaseous fuels this combustor was operated in a lean-lean mode with ultra long residence times. The Blue-water gas was also operated in a rich-lean mode. The results of these tests indicate the possibility of the existence of an 'optimum' gas turbine hydrogen - carbon monoxide based secondary fuel. Such a fuel would exhibit NOx and high efficiency over the entire engine operating range. It would also have sufficient stability range to allow normal light-off and engine acceleration. Solar Turbines Incorporated would like to emphasize that the results presented here have been obtained with experimental rig combustors. The technologies generated could, however, be utilized in future commercial gas turbines.

  7. Fundamental limits on gas-phase chemical reduction of NOx in a plasma

    SciTech Connect

    Penetrante, B.M.; Hsiao, M.C.; Merritt, B.T.; Vogtlin, G.E.

    1997-12-31

    In the plasma, the electrons do not react directly with the NOx molecules. The electrons collide mainly with the background gas molecules like N{sub 2}, O{sub 2} and H{sub 2}O. Electron impact on these molecules result partly in dissociation reactions that produce reactive species like N, O and OH. The NOx in the engine exhaust gas initially consist mostly of NO. The ground state nitrogen atom, N, is the only species that could lead to the chemical reduction of NO to N{sub 2}. The O radical oxidizes NO to NO{sub 2} leaving the same amount of NOx. The OH radical converts NO{sub 2} to nitric acid. Acid products in the plasma can easily get adsorbed on surfaces in the plasma reactor and in the pipes. When undetected, the absence of these oxidation products can often be mistaken for chemical reduction of NOx. In this paper the authors will examine the gas-phase chemical reduction of NOx. They will show that under the best conditions, the plasma can chemically reduce 1.6 grams of NOx per brake-horsepower-hour [g(NOx)/bhp-hr] when 5% of the engine output energy is delivered to the plasma.

  8. Method And Apparatus For Regenerating Nox Adsorbers

    DOEpatents

    Driscoll, J. Joshua; Endicott, Dennis L.; Faulkner, Stephen A.; Verkiel, Maarten

    2006-03-28

    Methods and apparatuses for regenerating a NOx adsorber coupled with an exhaust of an engine. An actuator drives a throttle valve to a first position when regeneration of the NOx adsorber is desired. The first position is a position that causes the regeneration of the NOx adsorber. An actuator drives the throttle valve to a second position while regeneration of the NOx adsorber is still desired. The second position being a position that is more open than the first position and operable to regenerate a NOx adsorber.

  9. Modified chemiluminescent NO analyzer accurately measures NOX

    NASA Technical Reports Server (NTRS)

    Summers, R. L.

    1978-01-01

    Installation of molybdenum nitric oxide (NO)-to-higher oxides of nitrogen (NOx) converter in chemiluminescent gas analyzer and use of air purge allow accurate measurements of NOx in exhaust gases containing as much as thirty percent carbon monoxide (CO). Measurements using conventional analyzer are highly inaccurate for NOx if as little as five percent CO is present. In modified analyzer, molybdenum has high tolerance to CO, and air purge substantially quenches NOx destruction. In test, modified chemiluminescent analyzer accurately measured NO and NOx concentrations for over 4 months with no denegration in performance.

  10. Characterization of superoxide overproduction by the D-LoopNox4-Nox2 cytochrome b558 in phagocytes – Differential sensitivity to calcium and phosphorylation events

    PubMed Central

    Carrichon, Laure; Picciocchi, Antoine; Debeurme, Franck; Defendi, Federica; Beaumel, Sylvain; Jesaitis, Algirdas J.; Dagher, Marie-Claire; Stasia, Marie-José

    2010-01-01

    NADPH oxidase is a crucial element of phagocytes involved in microbicidal mechanisms. It becomes active when membrane-bound cytochrome b558, the redox core, is assembled with cytosolic p47phox, p67phox, p40phox, and rac proteins to produce superoxide, the precursor for generation of toxic reactive oxygen species. In a previous study, we demonstrated that the potential second intracellular loop of Nox2 was essential to maintaining NADPH oxidase activity by controlling electron transfer from FAD to O2. Moreover, replacement of this loop by the Nox4-D-loop (D-loopNox4-Nox2) in PLB-985 cells induced superoxide overproduction. In the present investigation, we demonstrated that both soluble and particulate stimuli were able to induce this superoxide overproduction. Superoxide overproduction was also observed after phosphatidic acid activation in a purified cell-free-system assay. The highest oxidase activity was obtained after ionomycin and fMLF stimulation. In addition, enhanced sensitivity to Ca2+ influx was shown by thapsigargin, EDTA, or BTP2 treatment before fMLF activation. Mutated cytochrome b558 was less dependent on phosphorylation triggered by ERK1/2 during fMLF or PMA stimulation and by PI3K during OpZ stimulation. The superoxide overproduction of the D-loopNox4-Nox2 mutant may come from a change of responsiveness to intracellular Ca2+ level and to phosphorylation events during oxidase activation. Finally the D-loopNox4-Nox2 -PLB-985 cells were more effective against an attenuated strain of Pseudomonas aeruginosa compared to WT-Nox2 cells. The killing mechanism was biphasic, an early step of ROS production that was directly bactericidal, and a second oxidase-independent step related to the amount of ROS produced in the first step. PMID:20708598

  11. A simplified reaction mechanism for prediction of NO(x) emissions in the combustion of hydrocarbons

    NASA Technical Reports Server (NTRS)

    Kundu, K. P.; Deur, J. M.

    1992-01-01

    A simplified reaction mechanism is developed for the prediction of NO(x) in hydrocarbon combustion. The mechanism uses fewer reacting species and reaction steps than the detailed mechanisms available in the literature and therefore takes less computer time when used in CFD calculations. The mechanism has been used to calculate NO(x) emissions in the combustion of propane. With slight modifications, the same mechanism can be used to calculate NO(x) in the combustion of other hydrocarbons. Results obtained with the simplified reaction are compared with experimental results and results obtained with a detailed kinetic mechanism.

  12. Controlling NOx emission from industrial sources

    SciTech Connect

    Srivastava, R.K.; Nueffer, W.; Grano, D.; Khan, S.; Staudt, J.E.; Jozewicz, W.

    2005-07-01

    A number of regulatory actions focused on reducing NOx emissions from stationary combustion sources have been taken in the United States in the last decade. These actions include the Acid Rain NOx regulations, the Ozone Transport Commission's NOx Budget Program, and the NOx SIP Call rulemakings. In addition to these regulations, the recent Interstate Air Quality Rulemaking proposal and other bills in the Congress are focusing on additional reductions of NOx. Industrial combustion sources accounted for about 18016 of NOx emissions in the United States in 2000 and constituted the second largest emitting source category within stationary sources, only behind electric utility sources. Based on these data, reduction of NOx emissions from industrial combustion sources is an important consideration in efforts undertaken to address the environmental concerns associated with NOx. This paper discusses primary and secondary NOx control technologies applicable to various major categories of industrial sources. The sources considered in this paper include large boilers, furnaces and fired heaters, combustion turbines, large IC engines, and cement kilns. For each source category considered in this paper, primary NOx controls are discussed first, followed by a discussion of secondary NOx controls.

  13. NOx EMISSIONS PRODUCED WITH COMBUSTION OF POWDER RIVER BASIN COAL IN A UTILITY BOILER

    SciTech Connect

    John S. Nordin; Norman W. Merriam

    1997-04-01

    The objective of this report is to estimate the NOx emissions produced when Powder River Basin (PRB) coal is combusted in a utility boiler. The Clean Air Act regulations specify NOx limits of 0.45 lb/mm Btu (Phase I) and 0.40 lb/mm Btu (Phase II) for tangentially fired boilers, and 0.50 lb/mm 13tu (Phase II) and 0.46 lb/mm Btu (Phase II) for dry-bottom wall-fired boilers. The Clean Air Act regulations also specify other limits for other boiler types. Compliance for Phase I has been in effect since January 1, 1996. Compliance for Phase II goes into effect on January 1, 2000. Emission limits are expressed as equivalent NO{sub 2} even though NO (and sometimes N{sub 2}O) is the NOx species emitted during combustion. Regulatory agencies usually set even lower NOx emission limits in ozone nonattainment areas. In preparing this report, Western Research Institute (WRI) used published test results from utilities burning various coals, including PRB coal, using state-of-the art control technology for minimizing NOx emissions. Many utilities can meet Clean Air Act NOx emission limits using a combination of tight combustion control and low-NOx burners and by keeping furnaces clean (i.e., no slag buildup). In meeting these limits, some utilities also report problems such as increased carbon in their fly ash and excessive furnace tube corrosion. This report discusses utility experience. The theory of NOx emission formation during coal combustion as related to coal structure and how the coal is combusted is also discussed. From this understanding, projections are made for NOx emissions when processed PRB coal is combusted in a test similar to that done with other coals. As will be shown, there are a lot of conditions for achieving low NOx emissions, such as tight combustion control and frequent waterlancing of the furnace to avoid buildup of deposits.

  14. Effect of K loadings on nitrate formation/decomposition and on NOx storage performance of K-based NOx storage-reduction catalysts

    SciTech Connect

    Kim, Do Heui; Mudiyanselage, Kumudu K.; Szanyi, Janos; Kwak, Ja Hun; Zhu, Haiyang; Peden, Charles HF

    2013-10-25

    We have investigated nitrate formation and decomposition processes, and measured NOx storage performance on Pt-K2O/Al2O3 catalysts as a function of potassium loading. After NO2 adsorption at room temperature, ionic and bidentate nitrates were observed by fourier transform infra-red (FTIR) spectroscopy. The ratio of the former to the latter species increased with increasing potassium loading up to 10 wt%, and then stayed almost constant with additional K, demonstrating a clear dependence of loading on the morphology of the K species. Although both K2O(10)/Al2O3 and K2O(20)/Al2O3 samples have similar nitrate species after NO2 adsorption, the latter has more thermally stable nitrate species as evidenced by FTIR and NO2 temperature programmed desorption (TPD) results. With regard to NOx storage performance, the temperature of maximum NOx uptake (Tmax) is 573 K up to a potassium loading of 10 wt%. As the potassium loading increases from 10 wt% to 20 wt%, Tmax shifted from 573 K to 723 K. Moreover, the amount of NO uptake (38 cm3 NOx/g catal) at Tmax increased more than three times, indicating that efficiency of K in storing NOx is enhanced significantly at higher temperature, in good agreement with the NO2 TPD and FTIR results. Thus, a combination of characterization and NOx storage performance results demonstrates an unexpected effect of potassium loading on nitrate formation and decomposition processes; results important for developing Pt-K2O/Al2O3 for potential applications as high temperature NOx storage-reduction catalysts.

  15. Particle and gaseous emissions from individual diesel and CNG buses

    NASA Astrophysics Data System (ADS)

    Hallquist, Å. M.; Jerksjö, M.; Fallgren, H.; Westerlund, J.; Sjödin, Å.

    2012-10-01

    In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG)-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz) and CO2 with non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz). The gaseous constituents (CO, HC and NO) were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.). Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA 3.1. The buses studied were diesel-fuelled Euro II-V and CNG-fuelled Enhanced Environmental Friendly Vehicles (EEVs) with different after-treatment, including selective catalytic reduction (SCR), exhaust gas recirculation (EGR) and with and without diesel particulate filter (DPF). The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN) were EFPN, DPF = 8.0 ± 3.1 × 1014, EFPN, no DPF =2.8 ± 1.6 × 1015 and EFPN, CNG = 7.8 ± 5.7 × 1015 (kg fuel-1). In the accelerating mode size-resolved EFs showed unimodal number size distributions with peak diameters of 70-90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm. Emission factors for NOx expressed as NO2 equivalents for the diesel buses were on average 27 ± 7 g (kg fuel)-1 and for the CNG buses 41 ± 26 g (kg fuel)-1. An anti

  16. Particle and gaseous emissions from individual diesel and CNG buses

    NASA Astrophysics Data System (ADS)

    Hallquist, Å. M.; Jerksjö, M.; Fallgren, H.; Westerlund, J.; Sjödin, Å.

    2013-05-01

    In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG)-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz) and CO2 with a non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz). The gaseous constituents (CO, HC and NO) were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.). Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA3.1. The buses studied were diesel-fuelled Euro III-V and CNG-fuelled Enhanced Environmentally Friendly Vehicles (EEVs) with different after-treatment, including selective catalytic reduction (SCR), exhaust gas recirculation (EGR) and with and without diesel particulate filter (DPF). The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average a higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN) were EFPN, DPF = 4.4 ± 3.5 × 1014, EFPN, no DPF = 2.1 ± 1.0 × 1015 and EFPN, CNG = 7.8 ± 5.7 ×1015 kg fuel-1. In the accelerating mode, size-resolved emission factors (EFs) showed unimodal number size distributions with peak diameters of 70-90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode, bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm. Emission factors for NOx expressed as NO2 equivalents for the diesel buses were on average 27 ± 7 g (kg fuel)-1 and for the CNG buses 41 ± 26 g (kg

  17. Application of Low Dimensional Manifolds in NO(x) Prediction

    NASA Technical Reports Server (NTRS)

    Norris, A. T.

    1997-01-01

    A new post-processing technique has been developed, based on the Intrinsic Low Dimensional Manifold (ILDM) method of Maas and Pope. The ILDM method is a dynamical systems approach to the simplification of large chemical kinetic mechanisms. By identifying low-dimensional attracting manifolds, the method allows complex full mechanisms to be parameterized by just a few variables: In effect, generating reduced chemical mechanisms by an automatic procedure. These resulting mechanisms however, still retain all the species used in the full mechanism. The NO(x) post-processor takes an ILDM reduced mechanism and attempts to map this mechanism to the results of a CFD calculation. This mapping allows the NO(x) concentrations at each grid node to be obtained from the ILDM reduced mechanism, as well as other trace species of interest. Because a mapping procedure is used, this method is very fast, being able to process one million node calculations in just a few minutes.

  18. Photon detectors with gaseous amplification

    SciTech Connect

    Va`vra, J.

    1996-08-01

    Gaseous photon detectors, including very large 4{pi}-devices such as those incorporated in SLD and DELPHI, are finally delivering physics after many years of hard work. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photoelectrons. Among detector builders, there is hardly anybody who did not make mistakes in this area, and who does not have a healthy respect for the problems involved. This point is stressed in this paper, and it is suggested that only a very small operating phase space is available for running gaseous photon detectors in a very large system with good efficiency and few problems. In this paper the authors discuss what was done correctly or incorrectly in first generation photon detectors, and what would be their recommendations for second generation detectors. 56 refs., 11 figs.

  19. Gaseous fuel nuclear reactor research

    NASA Technical Reports Server (NTRS)

    Schwenk, F. C.; Thom, K.

    1975-01-01

    Gaseous-fuel nuclear reactors are described; their distinguishing feature is the use of fissile fuels in a gaseous or plasma state, thereby breaking the barrier of temperature imposed by solid-fuel elements. This property creates a reactor heat source that may be able to heat the propellant of a rocket engine to 10,000 or 20,000 K. At this temperature level, gas-core reactors would provide the breakthrough in propulsion needed to open the entire solar system to manned and unmanned spacecraft. The possibility of fuel recycling makes possible efficiencies of up to 65% and nuclear safety at reduced cost, as well as high-thrust propulsion capabilities with specific impulse up to 5000 sec.

  20. Planar Reflection of Gaseous Detonations

    NASA Astrophysics Data System (ADS)

    Damazo, Jason Scott

    Pipes containing flammable gaseous mixtures may be subjected to internal detonation. When the detonation normally impinges on a closed end, a reflected shock wave is created to bring the flow back to rest. This study built on the work of Karnesky (2010) and examined deformation of thin-walled stainless steel tubes subjected to internal reflected gaseous detonations. A ripple pattern was observed in the tube wall for certain fill pressures, and a criterion was developed that predicted when the ripple pattern would form. A two-dimensional finite element analysis was performed using Johnson-Cook material properties; the pressure loading created by reflected gaseous detonations was accounted for with a previously developed pressure model. The residual plastic strain between experiments and computations was in good agreement. During the examination of detonation-driven deformation, discrepancies were discovered in our understanding of reflected gaseous detonation behavior. Previous models did not accurately describe the nature of the reflected shock wave, which motivated further experiments in a detonation tube with optical access. Pressure sensors and schlieren images were used to examine reflected shock behavior, and it was determined that the discrepancies were related to the reaction zone thickness extant behind the detonation front. During these experiments reflected shock bifurcation did not appear to occur, but the unfocused visualization system made certainty impossible. This prompted construction of a focused schlieren system that investigated possible shock wave-boundary layer interaction, and heat-flux gauges analyzed the boundary layer behind the detonation front. Using these data with an analytical boundary layer solution, it was determined that the strong thermal boundary layer present behind the detonation front inhibits the development of reflected shock wave bifurcation.

  1. Recent work on gaseous detonations

    NASA Astrophysics Data System (ADS)

    Nettleton, M. A.

    The paper reviews recent progress in the field of gaseous detonations, with sections on shock diffraction and reflection, the transition to detonation, hybrid, spherically-imploding, and galloping and stuttering fronts, their structure, their transmission and quenching by additives, the critical energy for initiation and detonation of more unusual fuels. The final section points out areas where our understanding is still far from being complete and contains some suggestions of ways in which progress might be made.

  2. Solid sorbent control of nitrogen oxides (NOx). Final report, September 1996--January 1999

    SciTech Connect

    Lee, M.R.

    1999-01-18

    Solid materials have demonstrated applicable control of combustion-source NOx. A support material of (gamma)-alumina can provide improved NOx sorption in comparison to a previously applied sorbent, magnesia-coated vermiculite. NOx sorption of treated (gamma)-alumina correlates with the ionization potential of the group-1 element. General mechanisms of NOx sorption have been developed for untreated, K{sub 2}CO{sub 3}-treated and KOH-treated (gamma)-alumina. Sorption of NO appears to increase formation of nitrite. Untreated (gamma)-alumina formed little nitrite. For the treated (gamma)-alumina, the ratio of nitrite-nitrate formed relates to the ratio of NO-to-NO{sub 2} sorbed. Additional NO{sub 2} exposure converts nitrite into nitrate and NO. This nitrite-to-nitrate conversion correlates with the thermal stability of subsurface species. In addition, thermal-decomposition tests indicated similarities of NOx-exposed sorbents to nitrite and nitrate salts. The proposed mechanisms suggest that formed nitrite stability is crucial to improving NOx sorption. Effects of additional gases (O{sub 2}, SO{sub 2}, CO{sub 2}, or water vapor) to NO and NO{sub 2} sorption at 25 and 250 deg C by untreated, K{sub 2}CO{sub 3}-treated and KOH-treated (gamma)-alumina were evaluated. Only SO{sub 2} and water vapor were observed to affect NOx sorption.

  3. Ischemia induces nuclear NOX2 expression in cardiomyocytes and subsequently activates apoptosis.

    PubMed

    Meischl, C; Krijnen, P A J; Sipkens, J A; Cillessen, S A G M; Muñoz, I Gámez; Okroj, M; Ramska, M; Muller, A; Visser, C A; Musters, R J P; Simonides, W S; Hack, C E; Roos, D; Niessen, H W M

    2006-06-01

    In previous work we have demonstrated increased expression of NOX2 in cardiomyocytes of infarcted human hearts. In the present manuscript we investigated the functional role of NOX2 in ischemically challenged H9c2 cells, a rat cardiomyoblast cell line, and adult rat cardiomyocytes. Expression of NOX2 in H9c2 cells was confirmed by RT-PCR. In Western-blot experiments, increased NOX2 expression was detected during ischemia, which was inhibited by transcription and translation inhibitors. Surprisingly, under ischemia, in addition to an increased cytosolic expression, NOX2 was localized mainly in the nucleus of apoptotic cardiomyocytes, where it colocalized with nitrotyrosine residues and activated caspase 3. Inhibition of reactive-oxygen-species generation with the flavoenzyme inhibitor diphenylene iodonium (DPI) and the NADPH-oxidase inhibitor apocynin led to a significantly decreased induction of apoptosis as assessed by quantification of caspase-3 activity and by TUNEL analysis. These results demonstrate that NOX2 is expressed in the nucleus of cardiomyocytes during apoptosis and that it likely participates in proapoptotic signaling. To the best of our knowledge, this is the first demonstration of nuclear NOX2 expression and its involvement in cardiomyocyte apoptosis.

  4. Entamoeba histolytica induces cell death of HT29 colonic epithelial cells via NOX1-derived ROS.

    PubMed

    Kim, Kyeong Ah; Kim, Ju Young; Lee, Young Ah; Min, Arim; Bahk, Young Yil; Shin, Myeong Heon

    2013-02-01

    Entamoeba histolytica, which causes amoebic colitis and occasionally liver abscess in humans, is able to induce host cell death. However, signaling mechanisms of colon cell death induced by E. histolytica are not fully elucidated. In this study, we investigated the signaling role of NOX in cell death of HT29 colonic epithelial cells induced by E. histolytica. Incubation of HT29 cells with amoebic trophozoites resulted in DNA fragmentation that is a hallmark of apoptotic cell death. In addition, E. histolytica generate intracellular reactive oxygen species (ROS) in a contact-dependent manner. Inhibition of intracellular ROS level with treatment with DPI, an inhibitor of NADPH oxidases (NOXs), decreased Entamoeba-induced ROS generation and cell death in HT29 cells. However, pan-caspase inhibitor did not affect E. histolytica-induced HT29 cell death. In HT29 cells, catalytic subunit NOX1 and regulatory subunit Rac1 for NOX1 activation were highly expressed. We next investigated whether NADPH oxidase 1 (NOX1)-derived ROS is closely associated with HT29 cell death induced by E. histolytica. Suppression of Rac1 by siRNA significantly inhibited Entamoeba-induced cell death. Moreover, knockdown of NOX1 by siRNA, effectively inhibited E. histolytica-triggered DNA fragmentation in HT29 cells. These results suggest that NOX1-derived ROS is required for apoptotic cell death in HT29 colon epithelial cells induced by E. histolytica.

  5. Nox2 mediates skeletal muscle insulin resistance induced by a high fat diet.

    PubMed

    Souto Padron de Figueiredo, Alvaro; Salmon, Adam B; Bruno, Francesca; Jimenez, Fabio; Martinez, Herman G; Halade, Ganesh V; Ahuja, Seema S; Clark, Robert A; DeFronzo, Ralph A; Abboud, Hanna E; El Jamali, Amina

    2015-05-22

    Inflammation and oxidative stress through the production of reactive oxygen species (ROS) are consistently associated with metabolic syndrome/type 2 diabetes. Although the role of Nox2, a major ROS-generating enzyme, is well described in host defense and inflammation, little is known about its potential role in insulin resistance in skeletal muscle. Insulin resistance induced by a high fat diet was mitigated in Nox2-null mice compared with wild-type mice after 3 or 9 months on the diet. High fat feeding increased Nox2 expression, superoxide production, and impaired insulin signaling in skeletal muscle tissue of wild-type mice but not in Nox2-null mice. Exposure of C2C12 cultured myotubes to either high glucose concentration, palmitate, or H2O2 decreases insulin-induced Akt phosphorylation and glucose uptake. Pretreatment with catalase abrogated these effects, indicating a key role for H2O2 in mediating insulin resistance. Down-regulation of Nox2 in C2C12 cells by shRNA prevented insulin resistance induced by high glucose or palmitate but not H2O2. These data indicate that increased production of ROS in insulin resistance induced by high glucose in skeletal muscle cells is a consequence of Nox2 activation. This is the first report to show that Nox2 is a key mediator of insulin resistance in skeletal muscle.

  6. 40 CFR 97.53 - Recordation of NOX allowance allocations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Recordation of NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Tracking System § 97.53 Recordation of NOX allowance allocations. (a) The Administrator will record the...

  7. 40 CFR 97.50 - NOX Allowance Tracking System accounts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Tracking System § 97.50 NOX Allowance Tracking System accounts. (a) Nature and function of...

  8. 40 CFR 96.25 - NOX Budget permit revisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX Budget permit revisions. 96.25... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.25 NOX Budget permit revisions. (a) For a NOX Budget source with a title V operating...

  9. 40 CFR 96.11 - Alternate NOX authorized account representative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Alternate NOX authorized account... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Authorized Account Representative for NOX Budget Sources § 96.11 Alternate...

  10. 40 CFR 97.53 - Recordation of NOX allowance allocations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Recordation of NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Tracking System § 97.53 Recordation of NOX allowance allocations. (a) The Administrator will record the...

  11. 40 CFR 97.142 - CAIR NOX allowance allocations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false CAIR NOX allowance allocations. 97.142... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Allowance Allocations § 97.142 CAIR NOX allowance allocations. (a)(1) The baseline heat input (in mmBtu) used...

  12. 40 CFR 96.50 - NOX Allowance Tracking System accounts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Tracking System § 96.50 NOX Allowance Tracking System accounts. (a) Nature...

  13. 40 CFR 96.42 - NOX allowance allocations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX allowance allocations. 96.42... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Allocations § 96.42 NOX allowance allocations. (a)(1) The heat input (in mmBtu) used...

  14. 40 CFR 97.42 - NOX allowance allocations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX allowance allocations. 97.42... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Allocations § 97.42 NOX allowance allocations. (a)(1) The heat input (in mmBtu) used for calculating...

  15. 40 CFR 97.23 - NOX Budget permit contents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX Budget permit contents. 97.23... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.23 NOX Budget permit contents. (a) Each NOX Budget permit will contain, in a format prescribed by the...

  16. 40 CFR 96.11 - Alternate NOX authorized account representative.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Alternate NOX authorized account... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Authorized Account Representative for NOX Budget Sources § 96.11 Alternate...

  17. 40 CFR 96.11 - Alternate NOX authorized account representative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Alternate NOX authorized account... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Authorized Account Representative for NOX Budget Sources § 96.11 Alternate...

  18. 40 CFR 96.11 - Alternate NOX authorized account representative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Alternate NOX authorized account... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Authorized Account Representative for NOX Budget Sources § 96.11 Alternate...

  19. 40 CFR 96.53 - Recordation of NOX allowance allocations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Recordation of NOX allowance... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Tracking System § 96.53 Recordation of NOX allowance allocations. (a)...

  20. 40 CFR 97.24 - NOX Budget permit revisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX Budget permit revisions. 97.24... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.24 NOX Budget permit revisions. (a) For a NOX Budget source with a title V operating permit, except as...

  1. 40 CFR 96.53 - Recordation of NOX allowance allocations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Recordation of NOX allowance... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Tracking System § 96.53 Recordation of NOX allowance allocations. (a)...

  2. 40 CFR 96.50 - NOX Allowance Tracking System accounts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Tracking System § 96.50 NOX Allowance Tracking System accounts. (a) Nature...

  3. 40 CFR 96.23 - NOX Budget permit contents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX Budget permit contents. 96.23... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.23 NOX Budget permit contents. (a) Each NOX Budget permit (including any draft or...

  4. 40 CFR 96.50 - NOX Allowance Tracking System accounts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Tracking System § 96.50 NOX Allowance Tracking System accounts. (a) Nature...

  5. 40 CFR 97.53 - Recordation of NOX allowance allocations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Recordation of NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Tracking System § 97.53 Recordation of NOX allowance allocations. (a) The Administrator will record the...

  6. 40 CFR 97.50 - NOX Allowance Tracking System accounts.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Tracking System § 97.50 NOX Allowance Tracking System accounts. (a) Nature and function of...

  7. 40 CFR 97.53 - Recordation of NOX allowance allocations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Recordation of NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Tracking System § 97.53 Recordation of NOX allowance allocations. (a) The Administrator will record the...

  8. 40 CFR 96.50 - NOX Allowance Tracking System accounts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Tracking System § 96.50 NOX Allowance Tracking System accounts. (a) Nature...

  9. 40 CFR 96.142 - CAIR NOX allowance allocations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false CAIR NOX allowance allocations. 96.142... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Allowance Allocations § 96.142 CAIR NOX allowance allocations. (a)(1) The baseline heat...

  10. 40 CFR 97.50 - NOX Allowance Tracking System accounts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Tracking System § 97.50 NOX Allowance Tracking System accounts. (a) Nature and function of...

  11. 40 CFR 97.50 - NOX Allowance Tracking System accounts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Tracking System § 97.50 NOX Allowance Tracking System accounts. (a) Nature and function of...

  12. 40 CFR 97.142 - CAIR NOX allowance allocations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false CAIR NOX allowance allocations. 97.142... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Allowance Allocations § 97.142 CAIR NOX allowance allocations. (a)(1) The baseline heat input (in mmBtu) used...

  13. 40 CFR 96.42 - NOX allowance allocations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false NOX allowance allocations. 96.42... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Allocations § 96.42 NOX allowance allocations. (a)(1) The heat input (in mmBtu) used...

  14. 40 CFR 96.42 - NOX allowance allocations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false NOX allowance allocations. 96.42... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Allocations § 96.42 NOX allowance allocations. (a)(1) The heat input (in mmBtu) used...

  15. 40 CFR 97.24 - NOX Budget permit revisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX Budget permit revisions. 97.24... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.24 NOX Budget permit revisions. (a) For a NOX Budget source with a title V operating permit, except as...

  16. 40 CFR 97.42 - NOX allowance allocations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX allowance allocations. 97.42... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Allocations § 97.42 NOX allowance allocations. (a)(1) The heat input (in mmBtu) used for calculating...

  17. 40 CFR 96.23 - NOX Budget permit contents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false NOX Budget permit contents. 96.23... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.23 NOX Budget permit contents. (a) Each NOX Budget permit (including any draft or...

  18. 40 CFR 96.23 - NOX Budget permit contents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX Budget permit contents. 96.23... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.23 NOX Budget permit contents. (a) Each NOX Budget permit (including any draft or...

  19. 40 CFR 97.42 - NOX allowance allocations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX allowance allocations. 97.42... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Allocations § 97.42 NOX allowance allocations. (a)(1) The heat input (in mmBtu) used for calculating...

  20. 40 CFR 97.24 - NOX Budget permit revisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false NOX Budget permit revisions. 97.24... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.24 NOX Budget permit revisions. (a) For a NOX Budget source with a title V operating permit, except as...

  1. 40 CFR 96.42 - NOX allowance allocations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX allowance allocations. 96.42... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Allocations § 96.42 NOX allowance allocations. (a)(1) The heat input (in mmBtu) used...

  2. 40 CFR 96.42 - NOX allowance allocations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX allowance allocations. 96.42... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Allocations § 96.42 NOX allowance allocations. (a)(1) The heat input (in mmBtu) used...

  3. 40 CFR 96.23 - NOX Budget permit contents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Budget permit contents. 96.23... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.23 NOX Budget permit contents. (a) Each NOX Budget permit (including any draft or...

  4. 40 CFR 96.25 - NOX Budget permit revisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX Budget permit revisions. 96.25... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.25 NOX Budget permit revisions. (a) For a NOX Budget source with a title V operating...

  5. 40 CFR 96.11 - Alternate NOX authorized account representative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Alternate NOX authorized account... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Authorized Account Representative for NOX Budget Sources § 96.11 Alternate...

  6. 40 CFR 96.25 - NOX Budget permit revisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Budget permit revisions. 96.25... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.25 NOX Budget permit revisions. (a) For a NOX Budget source with a title V operating...

  7. 40 CFR 96.50 - NOX Allowance Tracking System accounts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Tracking System § 96.50 NOX Allowance Tracking System accounts. (a) Nature...

  8. 40 CFR 97.23 - NOX Budget permit contents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX Budget permit contents. 97.23... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.23 NOX Budget permit contents. (a) Each NOX Budget permit will contain, in a format prescribed by the...

  9. 40 CFR 96.25 - NOX Budget permit revisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false NOX Budget permit revisions. 96.25... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.25 NOX Budget permit revisions. (a) For a NOX Budget source with a title V operating...

  10. 40 CFR 96.142 - CAIR NOX allowance allocations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false CAIR NOX allowance allocations. 96.142... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Allowance Allocations § 96.142 CAIR NOX allowance allocations. (a)(1) The baseline heat...

  11. 40 CFR 97.42 - NOX allowance allocations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false NOX allowance allocations. 97.42... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Allocations § 97.42 NOX allowance allocations. (a)(1) The heat input (in mmBtu) used for calculating...

  12. 40 CFR 96.25 - NOX Budget permit revisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false NOX Budget permit revisions. 96.25... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.25 NOX Budget permit revisions. (a) For a NOX Budget source with a title V operating...

  13. 40 CFR 97.50 - NOX Allowance Tracking System accounts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Tracking System § 97.50 NOX Allowance Tracking System accounts. (a) Nature and function of...

  14. 40 CFR 97.24 - NOX Budget permit revisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Budget permit revisions. 97.24... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.24 NOX Budget permit revisions. (a) For a NOX Budget source with a title V operating permit, except as...

  15. 40 CFR 97.23 - NOX Budget permit contents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false NOX Budget permit contents. 97.23... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.23 NOX Budget permit contents. (a) Each NOX Budget permit will contain, in a format prescribed by the...

  16. Recombinant Nox4 cytosolic domain produced by a cell or cell-free base systems exhibits constitutive diaphorase activity

    SciTech Connect

    Nguyen, Minh Vu Chuong; Zhang, Leilei; Lhomme, Stanislas; Mouz, Nicolas

    2012-03-16

    Highlights: Black-Right-Pointing-Pointer A comparison of two bacterial cell and cell-free protein expression systems is presented. Black-Right-Pointing-Pointer Soluble and active truncated Nox4 proteins are produced. Black-Right-Pointing-Pointer Nox4 has a constitutive diaphorase activity which is independent of cytosolic factors. Black-Right-Pointing-Pointer Isoform Nox4B is unable to initiate the first electronic transfer step. Black-Right-Pointing-Pointer Findings contribute to the understanding of the mechanism of Nox4 oxidase activity. -- Abstract: The membrane protein NADPH (nicotinamide adenine dinucleotide phosphate) oxidase Nox4 constitutively generates reactive oxygen species differing from other NADPH oxidases activity, particularly in Nox2 which needs a stimulus to be active. Although the precise mechanism of production of reactive oxygen species by Nox2 is well characterized, the electronic transfer throughout Nox4 remains unclear. Our study aims to investigate the initial electronic transfer step (diaphorase activity) of the cytosolic tail of Nox4. For this purpose, we developed two different approaches to produce soluble and active truncated Nox4 proteins. We synthesized soluble recombinant proteins either by in vitro translation or by bacteria induction. While proteins obtained by bacteria induction demonstrate an activity of 4.4 {+-} 1.7 nmol/min/nmol when measured against iodonitro tetrazolium chloride and 20.5 {+-} 2.8 nmol/min/nmol with cytochrome c, the soluble proteins produced by cell-free expression system exhibit a diaphorase activity with a turn-over of 26 {+-} 2.6 nmol/min/nmol when measured against iodonitro tetrazolium chloride and 48 {+-} 20.2 nmol/min/nmol with cytochrome c. Furthermore, the activity of the soluble proteins is constitutive and does not need any stimulus. We also show that the cytosolic tail of the isoform Nox4B lacking the first NADPH binding site is unable to demonstrate any diaphorase activity pointing out the

  17. Comprehensive Genomic Analysis and Expression Profiling of the NOX Gene Families under Abiotic Stresses and Hormones in Plants.

    PubMed

    Chang, Yan-Li; Li, Wen-Yan; Miao, Hai; Yang, Shuai-Qi; Li, Ri; Wang, Xiang; Li, Wen-Qiang; Chen, Kun-Ming

    2016-03-01

    Plasma membrane NADPH oxidases (NOXs) are key producers of reactive oxygen species under both normal and stress conditions in plants and they form functional subfamilies. Studies of these subfamilies indicated that they show considerable evolutionary selection. We performed a comparative genomic analysis that identified 50 ferric reduction oxidases (FRO) and 77 NOX gene homologs from 20 species representing the eight major plant lineages within the supergroup Plantae: glaucophytes, rhodophytes, chlorophytes, bryophytes, lycophytes, gymnosperms, monocots, and eudicots. Phylogenetic and structural analysis classified these FRO and NOX genes into four well-conserved groups represented as NOX, FRO I, FRO II, and FRO III. Further analysis of NOXs of phylogenetic and exon/intron structures showed that single intron loss and gain had occurred, yielding the diversified gene structures during the evolution of NOXs family genes and which were classified into four conserved subfamilies which are represented as Sub.I, Sub.II, Sub.III, and Sub.IV. Additionally, both available global microarray data analysis and quantitative real-time PCR experiments revealed that the NOX genes in Arabidopsis and rice (Oryza sativa) have different expression patterns in different developmental stages, various abiotic stresses and hormone treatments. Finally, coexpression network analysis of NOX genes in Arabidopsis and rice revealed that NOXs have significantly correlated expression profiles with genes which are involved in plants metabolic and resistance progresses. All these results suggest that NOX family underscores the functional diversity and divergence in plants. This finding will facilitate further studies of the NOX family and provide valuable information for functional validation of this family in plants. PMID:26907500

  18. Comprehensive Genomic Analysis and Expression Profiling of the NOX Gene Families under Abiotic Stresses and Hormones in Plants.

    PubMed

    Chang, Yan-Li; Li, Wen-Yan; Miao, Hai; Yang, Shuai-Qi; Li, Ri; Wang, Xiang; Li, Wen-Qiang; Chen, Kun-Ming

    2016-02-23

    Plasma membrane NADPH oxidases (NOXs) are key producers of reactive oxygen species under both normal and stress conditions in plants and they form functional subfamilies. Studies of these subfamilies indicated that they show considerable evolutionary selection. We performed a comparative genomic analysis that identified 50 ferric reduction oxidases (FRO) and 77 NOX gene homologs from 20 species representing the eight major plant lineages within the supergroup Plantae: glaucophytes, rhodophytes, chlorophytes, bryophytes, lycophytes, gymnosperms, monocots, and eudicots. Phylogenetic and structural analysis classified these FRO and NOX genes into four well-conserved groups represented as NOX, FRO I, FRO II, and FRO III. Further analysis of NOXs of phylogenetic and exon/intron structures showed that single intron loss and gain had occurred, yielding the diversified gene structures during the evolution of NOXs family genes and which were classified into four conserved subfamilies which are represented as Sub.I, Sub.II, Sub.III, and Sub.IV. Additionally, both available global microarray data analysis and quantitative real-time PCR experiments revealed that the NOX genes in Arabidopsis and rice (Oryza sativa) have different expression patterns in different developmental stages, various abiotic stresses and hormone treatments. Finally, coexpression network analysis of NOX genes in Arabidopsis and rice revealed that NOXs have significantly correlated expression profiles with genes which are involved in plants metabolic and resistance progresses. All these results suggest that NOX family underscores the functional diversity and divergence in plants. This finding will facilitate further studies of the NOX family and provide valuable information for functional validation of this family in plants.

  19. Comprehensive Genomic Analysis and Expression Profiling of the NOX Gene Families under Abiotic Stresses and Hormones in Plants

    PubMed Central

    Chang, Yan-Li; Li, Wen-Yan; Miao, Hai; Yang, Shuai-Qi; Li, Ri; Wang, Xiang; Li, Wen-Qiang; Chen, Kun-Ming

    2016-01-01

    Plasma membrane NADPH oxidases (NOXs) are key producers of reactive oxygen species under both normal and stress conditions in plants and they form functional subfamilies. Studies of these subfamilies indicated that they show considerable evolutionary selection. We performed a comparative genomic analysis that identified 50 ferric reduction oxidases (FRO) and 77 NOX gene homologs from 20 species representing the eight major plant lineages within the supergroup Plantae: glaucophytes, rhodophytes, chlorophytes, bryophytes, lycophytes, gymnosperms, monocots, and eudicots. Phylogenetic and structural analysis classified these FRO and NOX genes into four well-conserved groups represented as NOX, FRO I, FRO II, and FRO III. Further analysis of NOXs of phylogenetic and exon/intron structures showed that single intron loss and gain had occurred, yielding the diversified gene structures during the evolution of NOXs family genes and which were classified into four conserved subfamilies which are represented as Sub.I, Sub.II, Sub.III, and Sub.IV. Additionally, both available global microarray data analysis and quantitative real-time PCR experiments revealed that the NOX genes in Arabidopsis and rice (Oryza sativa) have different expression patterns in different developmental stages, various abiotic stresses and hormone treatments. Finally, coexpression network analysis of NOX genes in Arabidopsis and rice revealed that NOXs have significantly correlated expression profiles with genes which are involved in plants metabolic and resistance progresses. All these results suggest that NOX family underscores the functional diversity and divergence in plants. This finding will facilitate further studies of the NOX family and provide valuable information for functional validation of this family in plants. PMID:26907500

  20. Mixing and NO(x) Emission Calculations of Confined Reacting Jet Flows in a Cylindrical Duct

    NASA Technical Reports Server (NTRS)

    Holdeman, James D. (Technical Monitor); Oechsle, Victor L.

    2003-01-01

    Rapid mixing of cold lateral jets with hot cross-stream flows in confined configurations is of practical interest in gas turbine combustors as it strongly affects combustor exit temperature quality, and gaseous emissions in for example rich-lean combustion. It is therefore important to further improve our fundamental understanding of the important processes of dilution jet mixing especially when the injected jet mass flow rate exceeds that of the cross-stream. The results reported in this report describe some of the main flow characteristics which develop in the mixing process in a cylindrical duct. A 3-dimensional tool has been used to predict the mixing flow field characteristics and NOx emission in a quench section of an RQL combustor, Eighteen configurations have been analyzed in a circular geometry in a fully reacting environment simulating the operating condition of an actual RQL gas turbine combustion liner. The evaluation matrix was constructed by varying three parameters: 1) jet-to-mainstream momentum-flux ratio (J), 2) orifice shape or orifice aspect ratio, and 3) slot slant angle. The results indicate that the mixing flow field significantly varies with the value of the jet penetration and subsequently, slanting elongated slots generally improve the mixing uniformity at high J conditions. Round orifices produce more uniform mixing and low NO(x) emissions at low J due to the strong and adequate jet penetration. No significant correlation was found between the NO(x) production rates and the mixing deviation parameters, however, strong correlation was found between NO(x) formation and jet penetration. In the computational results, most of the NO(x) formation occurred behind the orifice starting at the orifice wake region. Additional NO(x) is formed upstream of the orifice in certain configurations with high J conditions due to the upstream recirculation.

  1. 40 CFR 97.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 97.388 Section 97.388 Protection of Environment... NOX AND SO2 TRADING PROGRAMS CAIR NOX Ozone Season Opt-in Units § 97.388 CAIR NOX Ozone...

  2. 40 CFR 97.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 97.388 Section 97.388 Protection of Environment... NOX AND SO2 TRADING PROGRAMS CAIR NOX Ozone Season Opt-in Units § 97.388 CAIR NOX Ozone...

  3. 40 CFR 97.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 97.388 Section 97.388 Protection of Environment... NOX AND SO2 TRADING PROGRAMS CAIR NOX Ozone Season Opt-in Units § 97.388 CAIR NOX Ozone...

  4. 40 CFR 97.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 97.388 Section 97.388 Protection of Environment... NOX AND SO2 TRADING PROGRAMS CAIR NOX Ozone Season Opt-in Units § 97.388 CAIR NOX Ozone...

  5. 40 CFR 97.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 97.388 Section 97.388 Protection of Environment... NOX AND SO2 TRADING PROGRAMS CAIR NOX Ozone Season Opt-in Units § 97.388 CAIR NOX Ozone...

  6. Ammonia-Free NOx Control System

    SciTech Connect

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2005-03-31

    Research is being conducted under United States Department of Energy (DOE) Contract DE-FC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia.

  7. NOx control buys to peak in `98

    SciTech Connect

    McIlvaine, R.W.

    1995-10-01

    Titles I and IV of the Clean Air Act provide the legislative framework for a huge NOx reduction program now in operation. This reduction will have a substantial effect in reducing ground-level ozone. A new McIlvaine report concludes that US utilities and industrial companies during the next 10 years will spend more than $800 million annually to meet CAA`s NOx-control regulations. Much of that investment will be for low-NOx burners, which minimize NOx formation. Many utilities and industrial boilers can be retrofitted with a new generation of burners; however, this technology achieves less than 50% NOx reduction. Post-combustion technologies, such as selective catalytic reduction and selective noncatalytic reduction, can reduce NOx as much as 90%. Therefore, plants needing greater NOx reduction will use post-combustion technologies, often in combination with low-NOx burners. The peak order year for NOx-control equipment will be 1998, primarily because Title IV of CAA requires utilities to comply by 2000. Many industrial sources also will be ordering equipment in 1998.

  8. Ammonia-Free NOx Control System

    SciTech Connect

    Song Wu; Zhen Fan; Andrew H. Seltzer

    2005-06-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia.

  9. First-principles Analysis of NOx Adsorption on Anhydrous γ-Al2O3 Surfaces

    SciTech Connect

    Mei, Donghai; Ge, Qingfeng; Szanyi, Janos; Peden, Charles HF

    2009-04-09

    The interaction of nitrogen oxides NOx (x=1-3) with gamma Al2O3 has been investigated using first-principles density functional theory calculations. NO and NO2 weakly physisorb on the clean, dehydrated (100) and (110) surfaces of gamma Al2O3, whereas the adsorption of the NO3 radical is rather strong. Only the basic-like O-down adsorption configurations were found to be stable. The interaction between NOx and gamma Al2O3 can be described as a surface mediated electron transfer process. For single NOx adsorption, greater electron transfer from the surface to the adsorbate (negatively charged) yields stronger interactions between NOx and the surface. The adsorption of four combinations of NOx+NOy (x=1-3, y=2, 3) pairs on the (100) and the (110) facets of gamma Al2O3 were investigated. Except for the NO2+NO2 pair, a strong cooperative effect that substantially enhances the stability of NOx on both gamma Al2O3 surfaces was found. This cooperative effect consists of surface-mediated electron transfer processes resulting in a favorable electrostatic interaction between two adsorbed NOx species. The pair was found to be the thermodynamically most stable state among the co-adsorbed NOx+NOy pairs on both gamma Al2O3 surfaces. The results are used to analyze the experimentally observed NOx evolution during temperature programmed desorption from NO2-saturated gamma Al2O3 substrates. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  10. Peroxiredoxin 6 (Prdx6) supports NADPH oxidase1 (Nox1)-based superoxide generation and cell migration.

    PubMed

    Kwon, Jaeyul; Wang, Aibing; Burke, Devin J; Boudreau, Howard E; Lekstrom, Kristen J; Korzeniowska, Agnieszka; Sugamata, Ryuichi; Kim, Yong-Soo; Yi, Liang; Ersoy, Ilker; Jaeger, Stefan; Palaniappan, Kannappan; Ambruso, Daniel R; Jackson, Sharon H; Leto, Thomas L

    2016-07-01

    Nox1 is an abundant source of reactive oxygen species (ROS) in colon epithelium recently shown to function in wound healing and epithelial homeostasis. We identified Peroxiredoxin 6 (Prdx6) as a novel binding partner of Nox activator 1 (Noxa1) in yeast two-hybrid screening experiments using the Noxa1 SH3 domain as bait. Prdx6 is a unique member of the Prdx antioxidant enzyme family exhibiting both glutathione peroxidase and phospholipase A2 activities. We confirmed this interaction in cells overexpressing both proteins, showing Prdx6 binds to and stabilizes wild type Noxa1, but not the SH3 domain mutant form, Noxa1 W436R. We demonstrated in several cell models that Prdx6 knockdown suppresses Nox1 activity, whereas enhanced Prdx6 expression supports higher Nox1-derived superoxide production. Both peroxidase- and lipase-deficient mutant forms of Prdx6 (Prdx6 C47S and S32A, respectively) failed to bind to or stabilize Nox1 components or support Nox1-mediated superoxide generation. Furthermore, the transition-state substrate analogue inhibitor of Prdx6 phospholipase A2 activity (MJ-33) was shown to suppress Nox1 activity, suggesting Nox1 activity is regulated by the phospholipase activity of Prdx6. Finally, wild type Prdx6, but not lipase or peroxidase mutant forms, supports Nox1-mediated cell migration in the HCT-116 colon epithelial cell model of wound closure. These findings highlight a novel pathway in which this antioxidant enzyme positively regulates an oxidant-generating system to support cell migration and wound healing. PMID:27094494

  11. 40 CFR 97.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 97.52 Section 97.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND...

  12. 40 CFR 97.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 97.52 Section 97.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND...

  13. 40 CFR 97.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 97.52 Section 97.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND...

  14. 40 CFR 97.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 97.52 Section 97.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND...

  15. 40 CFR 97.12 - Changing NOX authorized account representative and alternate NOX authorized account...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Section 97.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized Account... authorized account representative; changes in owners and operators. (a) Changing NO X authorized...

  16. 40 CFR 97.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 97.52 Section 97.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND...

  17. Photo-oxidation of pinonaldehyde at low NOx: from chemistry to organic aerosol formation

    NASA Astrophysics Data System (ADS)

    Chacon-Madrid, H. J.; Henry, K. M.; Donahue, N. M.

    2013-03-01

    Pinonaldehyde oxidation by OH radicals under low-NOx conditions produces significant secondary organic aerosol (SOA) mass yields. Under concurrent UV illumination, mass yields are lower than high-NOx yields published earlier by our group. However, when OH radicals are produced via dark ozonolysis the SOA mass yields are comparable at high and low NOx. Because pinonaldehyde is a major first-generation gas-phase product of α-pinene oxidation by either ozone or OH radicals, its potential to form SOA serves as a molecular counterpoint to bulk SOA aging experiments involving SOA formed from α-pinene. Both the general tendency for aging reactions to produce more SOA and the sensitivity of the low-NOx products to UV photolysis observed in the bulk clearly occur for this single species as well. Photochemical oxidation of pinonaldehye and analogous first-generation terpene oxidation products are potentially a significant source of additional SOA in biogenically influenced air masses.

  18. The Fundamental Role of NOX Family Proteins in Plant Immunity and Their Regulation

    PubMed Central

    Wang, Ya-Jing; Wei, Xiao-Yong; Jing, Xiu-Qing; Chang, Yan-Li; Hu, Chun-Hong; Wang, Xiang; Chen, Kun-Ming

    2016-01-01

    NADPH oxidases (NOXs), also known as respiratory burst oxidase homologs (RBOHs), are the major source of reactive oxygen species (ROS), and are involved in many important processes in plants such as regulation of acclimatory signaling and programmed cell death (PCD). Increasing evidence shows that NOXs play crucial roles in plant immunity and their functions in plant immune responses are not as separate individuals but with other signal molecules such as kinases, Rac/Rop small GTPases and hormones, mediating a series of signal transmissions. In a similar way, NOX-mediated signaling also participates in abiotic stress response of plants. We summarized here the complex role and regulation mechanism of NOXs in mediating plant immune response, and the viewpoint that abiotic stress response of plants may be a kind of special plant immunity is also proposed. PMID:27240354

  19. Numerical study on seasonal variations of gaseous pollutants and particulate matters in Hong Kong/Pearl River Delta Region

    NASA Astrophysics Data System (ADS)

    Kwok, Roger Hiu Fung

    Air pollution in Hong Kong (HK) causes problems in visibility and public health, which are worsening over past few years. Out of particulate matters (PM) inhalable into respiratory system, 30% is contributed by sulfate (SO4), 40% by organic carbon (OC), and 10% by elemental carbon (EC). A meso-scale numerical modeling system CMAQ is devised to simulate the air quality in January (winter), April (spring), July (summer) and October (autumn) 2004, driven by meteorology simulated by MM5 and emission sources in China including Hong Kong. Observational and measurement data from Hong Kong Environmental Protection Department Air Quality network are compared with the model results. With respect to pollutant concentration level, model-observation agreement is reasonably well, especially in PM species sulfate, organic carbon (OC) and elemental carbon (EC); and gaseous species SO2, NOx and ozone. In terms of PM composition, the model agrees with the measurement in fractions of sulfate, OC and EC. Higher PM level in autumn and winter is associated with northeasterly winds due to continental outflow. To further investigate emission sources contributing to HK, a source apportioning method called Tagged Species Source Apportionment (TSSA) algorithm is applied to study contributions to level of SO4, SO2 and EC in HK. It is found that while sources beyond PRD are observed in entire HK during January and October 2004, emitting sectors are different among western HK, downtown area, and the east countryside. Specifically, power plants and vehicles from HK and Shenzhen affect the western new towns, while power plants, vehicles and ships within HK determine the downtown pollutants' level. The countryside is mainly influenced by sources beyond PRD.

  20. Gaseous composition measured by a chemical ionization mass spectrometer in fresh and aged ship plumes

    NASA Astrophysics Data System (ADS)

    Faxon, Cameron; Psichoudaki, Magda; Kuuluvainen, Heino; Hallquist, Åsa; Thomson, Erik; Pettersson, Jan; Hallquist, Mattias

    2015-04-01

    The port of Gothenburg is the largest port of the Nordic countries with numerous ships calling the port daily. The ship exhausts contain numerous pollutants including gases such as SO2 and NOx as well as particulate matter and soot. The exhaust also contains numerous organic compounds, a large fraction of which are unidentified. These organics are oxidized in the atmosphere producing more oxygenated and potentially less volatile compounds that may contribute to the secondary organic aerosol (SOA). This work focuses on the characterization of fresh gaseous species present in the exhaust plumes of the passing ships and also on their photochemical aging. Between 26 September and 12 November 2014 measurements were conducted at a sampling site located on a small peninsula at the entrance of Gothenburg's port. The campaign was divided in two periods. During the first period, the fresh plumes of the passing ships were measured through a main inlet. During the second period, the sample passed through the same inlet and was then introduced into a Potential Aerosol Mass (PAM) reactor. The PAM reactor uses UV lamps and high concentrations of oxidants (OH radicals and O3) to oxidize the organic species present in the plumes. The oxidation that takes place within the reactor can be equivalent to up to one week of atmospheric oxidation. Preliminary tests showed that the oxidation employed in the current camping corresponded to 3.4 days in the atmosphere. A Time-of-Flight Chemical Ionization Mass Spectrometer (ToF-CIMS) was employed to monitor the concentration of different organic species present in the fresh and aged plumes. Water (positive) and iodide (negative) ionization methods were employed were water was primarily used for fresh plumes (large fraction of non-polar compounds) while iodide was used for the aged plumes (primarily oxidised products). The H2O, O3 and SO2 concentrations inside the PAM chamber were monitored, and an organic tracer for OH exposure determination

  1. Hydrogen and Gaseous Fuel Safety and Toxicity

    SciTech Connect

    Lee C. Cadwallader; J. Sephen Herring

    2007-06-01

    Non-traditional motor fuels are receiving increased attention and use. This paper examines the safety of three alternative gaseous fuels plus gasoline and the advantages and disadvantages of each. The gaseous fuels are hydrogen, methane (natural gas), and propane. Qualitatively, the overall risks of the four fuels should be close. Gasoline is the most toxic. For small leaks, hydrogen has the highest ignition probability and the gaseous fuels have the highest risk of a burning jet or cloud.

  2. The Sensitivity of U.S. Surface Ozone Formation to NOx, and VOCs as Viewed from Space

    NASA Technical Reports Server (NTRS)

    Duncan, Bryan N.; Yoshida, Yasuko; Sillman, Sanford; Retscher, Christian; Pickering, Kenneth E.; Martin, Randall V.; Celarier, Edward A.

    2009-01-01

    We investigated variations in the sensitivity of surface ozone formation in summer to precursor species concentrations of volatile organic compounds (VOCs) and nitrogen oxides (NO(x)) as inferred from the ratio of tropospheric columns of formaldehyde and nitrogen dioxide from the Aura Ozone Monitoring Instrument (OMI). The data indicate that ozone formation became: 1. more sensitive to NO(x) over most of the U.S, from 2005 to 2007 because of substantial decreases in NO(x) emissions primarily from stationary sources, and 2. more sensitive to NO(x) with increasing temperature, in part because emissions of highly reactive, biogenic isoprene increase with temperature, thus increasing the total VOC reactivity. Based on our interpretation of the data, current strategies implemented to reduce unhealthy levels of surface ozone should focus more on reducing NO(x) emissions, except in some downtown areas which have historically benefited from reductions in VOC emissions.

  3. UREA INFRASTRUCTURE FOR UREA SCR NOX REDUCTION

    SciTech Connect

    Bunting, Bruce G.

    2000-08-20

    Urea SCR is currently the only proven NOX aftertreatment for diesel engines - high NOX reduction possible - some SCR catalyst systems are robust against fuel sulfur - durability has been demonstrated - many systems in the field - long history in other markets - Major limitations to acceptance - distribution of urea solution to end user - ensuring that urea solution is added to vehicle.

  4. LOW-CONCENTRATION NOX EMISSIONS MEASUREMENT

    EPA Science Inventory

    The paper gives results of a recent series of low-concentration nitrogen oxides (NOx) emission measurements, made by Midwest Research Institute (MRI) during U.S. EPA-sponsored Environmental Technology Verification (ETV) test of a NOx control system called Xonon (TM) Cool Combust...

  5. Reduce NOx and Improve Energy Efficiency

    SciTech Connect

    2005-05-01

    The U.S. Department of Energy's NOx and Energy Assessment Tool (NxEAT) is available at no charge to help the petroleum refining and chemicals industries develop a cost-effective, plant-wide strategy for NOx reduction and energy efficiency improvements.

  6. Prediction of the production of nitrogen oxide (NOx) in turbojet engines

    NASA Astrophysics Data System (ADS)

    Tsague, Louis; Tsogo, Joseph; Tatietse, Thomas Tamo

    Gaseous nitrogen oxides (NO+NO2=NOx) are known as atmospheric trace constituent. These gases remain a big concern despite the advances in low NOx emission technology because they play a critical role in regulating the oxidization capacity of the atmosphere according to Crutzen [1995. My life with O 3, NO x and other YZO x S; Nobel Lecture; Chemistry 1995; pp 195; December 8, 1995] . Aircraft emissions of nitrogen oxides ( NOx) are regulated by the International Civil Aviation Organization. The prediction of NOx emission in turbojet engines by combining combustion operational data produced information showing correlation between the analytical and empirical results. There is close similarity between the calculated emission index and experimental data. The correlation shows improved accuracy when the 2124 experimental data from 11 gas turbine engines are evaluated than a previous semi empirical correlation approach proposed by Pearce et al. [1993. The prediction of thermal NOx in gas turbine exhausts. Eleventh International Symposium on Air Breathing Engines, Tokyo, 1993, pp. 6-9]. The new method we propose predict the production of NOx with far more improved accuracy than previous methods. Since a turbojet engine works in an atmosphere where temperature, pressure and humidity change frequently, a correction factor is developed with standard atmospheric laws and some correlations taken from scientific literature [Swartwelder, M., 2000. Aerospace engineering 410 Term Project performance analysis, November 17, 2000, pp. 2-5; Reed, J.A. Java Gas Turbine Simulator Documentation. pp. 4-5]. The new correction factor is validated with experimental observations from 19 turbojet engines cruising at altitudes of 9 and 13 km given in the ICAO repertory [Middleton, D., 1992. Appendix K (FAA/SETA). Section 1: Boeing Method Two Indices, 1992, pp. 2-3]. This correction factor will enable the prediction of cruise NOx emissions of turbojet engines at cruising speeds. The ICAO

  7. Simultaneous and Real-time Measurement of Gaseous Ammonia and Particulate Ammonium

    NASA Astrophysics Data System (ADS)

    Kang, E.; Lee, J. H.

    2001-05-01

    Gaseous ammonia reacts with acidic gaseous species to neutralize atmospheric acidity and forms ammonium salts. In this neutralization reaction, ammonia is converted to ammonium ion in the particles. It plays an important role as CCN (cloud condensation nuclei) in the cloud formation. Moreover it plays a role on the cooling effect resulting from the reflection of solar radiation back to the space. Therefore, an improved simultaneous and real-time measurement technique for gaseous ammonia/particulate ammonium is needed to study the formation mechanism of CCN. Dual channel system for simultaneous and ream-time measurement of gaseous ammonia/particulate ammonium is described. In the 1st channel both gaseous ammonia/particulate ammonium is collected through a glass coil sampling system without citric acid coated denuder. In the 2nd channel gaseous ammonia is removed from the citric acid coated denuder and only particulate ammonium is collected through a glass coil sampling system. Using continuous flow injection system, collected ammonia (ammonium) reacts with sodium sulfite and o-phthaldialdehyde producing fluorescent product, which is detected by the fluorescence detector. The 1st channel signal represents the sum of gaseous ammonia and particulate ammonium, and the 2nd channel signal with the citric acid coated denuder represents only particulate ammonium. The difference in signal between two channels represents gaseous ammonia. This system shows each signal every second, and the baseline is recorded every 3 or 4 hours. Collection efficiency for gaseous ammonia was determined using consecutive two glass coil samplers. For the 2nd channel, collection efficiency of particulate ammonium is tested adapting consecutive two coil samplers. Gaseous ammonia and particulate ammonium were measured in Kwangju, South Korea at real time by using improved dual channel measurement system, and the detailed results and discussion will be presented in the presentation.

  8. Chemiluminescence analyzer of NOx as a high-throughput screening tool in selective catalytic reduction of NO

    NASA Astrophysics Data System (ADS)

    Oh, Kwang Seok; Woo, Seong Ihl

    2011-10-01

    A chemiluminescence-based analyzer of NOx gas species has been applied for high-throughput screening of a library of catalytic materials. The applicability of the commercial NOx analyzer as a rapid screening tool was evaluated using selective catalytic reduction of NO gas. A library of 60 binary alloys composed of Pt and Co, Zr, La, Ce, Fe or W on Al2O3 substrate was tested for the efficiency of NOx removal using a home-built 64-channel parallel and sequential tubular reactor. The NOx concentrations measured by the NOx analyzer agreed well with the results obtained using micro gas chromatography for a reference catalyst consisting of 1 wt% Pt on γ-Al2O3. Most alloys showed high efficiency at 275 °C, which is typical of Pt-based catalysts for selective catalytic reduction of NO. The screening with NOx analyzer allowed to select Pt-Ce(X) (X=1-3) and Pt-Fe(2) as the optimal catalysts for NOx removal: 73% NOx conversion was achieved with the Pt-Fe(2) alloy, which was much better than the results for the reference catalyst and the other library alloys. This study demonstrates a sequential high-throughput method of practical evaluation of catalysts for the selective reduction of NO.

  9. Application of OMI Observations to a Space-Based Indicator of NOx and VOC Controls on Surface Ozone Formation

    NASA Technical Reports Server (NTRS)

    Duncan, Bryan N.; Yoshida, Yasuko; Olson, Jennifer R.; Sillman, Sanford; Martin, Randall V.; Lamsal, Lok; Hu, Yongtao; Pickering, Kenneth E.; Retscher, Christian; Allen, Dale J.; Crawford, James H.

    2010-01-01

    We investigated variations in the relative sensitivity of surface ozone formation in summer to precursor species concentrations of volatile organic compounds (VOCs) and nitrogen oxides (NOx) as inferred from the ratio of the tropospheric columns of formaldehyde to nitrogen dioxide (the "Ratio") from the Aura Ozone Monitoring Instrument (OMI). Our modeling study suggests that ozone formation decreases with reductions in VOCs at Ratios less than 1 and NOx at Ratios greater than 2; both NOx and VOC reductions may decrease ozone formation for Ratios between 1 and 2. Using this criteria. the OMI data indicate that ozone formation became: 1. more sensitive to NOx over most of the United States from 2005 to 2007 because of the substantial decrease in NOx emissions, primarily from stationary sources, and the concomitant decrease in the tropospheric column of NO2. and 2. more sensitive to NOx with increasing temperature, in part because emissions of highly reactive, biogenic isoprene increase with temperature, thus increasing the total VOC reactivity. In cities with relatively low isoprene emissions (e.g .. Chicago). the data clearly indicate that ozone formation became more sensitive to NOx from 2005 to 2007. In cities with relatively high isoprene emissions (e.g ., Atlanta), we found that the increase in the Ratio due to decreasing NOx emissions was not obvious as this signal was convolved with variations in the Ratio associated with the temperature dependence of isoprene emissions and, consequently, the formaldehyde concentration.

  10. Nox Inhibitors & Therapies: Rational Design of Peptidic and Small Molecule Inhibitors.

    PubMed

    Cifuentes-Pagano, M Eugenia; Meijles, Daniel N; Pagano, Patrick J

    2015-01-01

    Oxidative stress-related diseases underlie many if not all of the major leading causes of death in United States and the Western World. Thus, enormous interest from both academia and pharmaceutical industry has been placed on the development of agents which attenuate oxidative stress. With that in mind, great efforts have been placed in the development of inhibitors of NADPH oxidase (Nox), the major enzymatic source of reactive oxygen species and oxidative stress in many cells and tissue. The regulation of a catalytically active Nox enzyme involves numerous protein-protein interactions which, in turn, afford numerous targets for inhibition of its activity. In this review, we will provide an updated overview of the available Nox inhibitors, both peptidic and small molecules, and discuss the body of data related to their possible mechanisms of action and specificity towards each of the various isoforms of Nox. Indeed, there have been some very notable successes. However, despite great commitment by many in the field, the need for efficacious and well-characterized, isoform-specific Nox inhibitors, essential for the treatment of major diseases as well as for delineating the contribution of a given Nox in physiological redox signalling, continues to grow.

  11. The Quest for Selective Nox Inhibitors and Therapeutics: Challenges, Triumphs and Pitfalls

    PubMed Central

    Cifuentes-Pagano, Eugenia; Meijles, Daniel N.

    2014-01-01

    Abstract Significance: Numerous studies in animal models and human subjects corroborate that elevated levels of reactive oxygen species (ROS) play a pivotal role in the progression of multiple diseases. As a major source of ROS in many organ systems, the NADPH oxidase (Nox) has become a prime target for therapeutic development. Recent Advances: In recent years, intense efforts have been dedicated to the development of pan- and isoform-specific Nox inhibitors as opposed to antioxidants that proved ineffective in clinical trials. Over the past decade, an array of compounds has been proposed in an attempt to fill this void. Critical Issues: Although many of these compounds have proven effective as Nox enzyme family inhibitors, isoform specificity has posed a formidable challenge to the scientific community. This review surveys the most prominent Nox inhibitors, and discusses potential isoform specificity, known mechanisms of action, and shortcomings. Some of these inhibitors hold substantial promise as targeted therapeutics. Future Directions: Increased insight into the mechanisms of action and regulation of this family of enzymes as well as atomic structures of key Nox subunits are expected to give way to a broader spectrum of more potent, efficacious, and specific molecules. These lead molecules will assuredly serve as a basis for drug development aimed at treating a wide array of diseases associated with increased Nox activity. Antioxid. Redox Signal. 20, 2741–2754. PMID:24070014

  12. Toluene decomposition performance and NOx by-product formation during a DBD-catalyst process.

    PubMed

    Guo, Yufang; Liao, Xiaobin; Fu, Mingli; Huang, Haibao; Ye, Daiqi

    2015-02-01

    Characteristics of toluene decomposition and formation of nitrogen oxide (NOx) by-products were investigated in a dielectric barrier discharge (DBD) reactor with/without catalyst at room temperature and atmospheric pressure. Four kinds of metal oxides, i.e., manganese oxide (MnOx), iron oxide (FeOx), cobalt oxide (CoOx) and copper oxide (CuO), supported on Al2O3/nickel foam, were used as catalysts. It was found that introducing catalysts could improve toluene removal efficiency, promote decomposition of by-product ozone and enhance CO2 selectivity. In addition, NOx was suppressed with the decrease of specific energy density (SED) and the increase of humidity, gas flow rate and toluene concentration, or catalyst introduction. Among the four kinds of catalysts, the CuO catalyst showed the best performance in NOx suppression. The MnOx catalyst exhibited the lowest concentration of O3 and highest CO2 selectivity but the highest concentration of NOx. A possible pathway for NOx production in DBD was discussed. The contributions of oxygen active species and hydroxyl radicals are dominant in NOx suppression.

  13. Nox Inhibitors & Therapies: Rational Design of Peptidic and Small Molecule Inhibitors

    PubMed Central

    Cifuentes-Pagano, M. Eugenia; Meijles, Daniel N.; Pagano, Patrick J.

    2016-01-01

    Oxidative stress-related diseases underlie many if not all of the major leading causes of death in United States and the Western World. Thus, enormous interest from both academia and pharmaceutical industry has been placed on the development of agents which attenuate oxidative stress. With that in mind, great efforts have been placed in the development of inhibitors of NADPH oxidase (Nox), the major enzymatic source of reactive oxygen species and oxidative stress in many cells and tissue. The regulation of a catalytically active Nox enzyme involves numerous protein-protein interactions which, in turn, afford numerous targets for inhibition of its activity. In this review, we will provide an updated overview of the available Nox inhibitors, both peptidic and small molecules, and discuss the body of data related to their possible mechanisms of action and specificity towards each of the various isoforms of Nox. Indeed, there have been some very notable successes. However, despite great commitment by many in the field, the need for efficacious and well-characterized, isoform-specific Nox inhibitors, essential for the treatment of major diseases as well as for delineating the contribution of a given Nox in physiological redox signalling, continues to grow. PMID:26510437

  14. Toluene decomposition performance and NOx by-product formation during a DBD-catalyst process.

    PubMed

    Guo, Yufang; Liao, Xiaobin; Fu, Mingli; Huang, Haibao; Ye, Daiqi

    2015-02-01

    Characteristics of toluene decomposition and formation of nitrogen oxide (NOx) by-products were investigated in a dielectric barrier discharge (DBD) reactor with/without catalyst at room temperature and atmospheric pressure. Four kinds of metal oxides, i.e., manganese oxide (MnOx), iron oxide (FeOx), cobalt oxide (CoOx) and copper oxide (CuO), supported on Al2O3/nickel foam, were used as catalysts. It was found that introducing catalysts could improve toluene removal efficiency, promote decomposition of by-product ozone and enhance CO2 selectivity. In addition, NOx was suppressed with the decrease of specific energy density (SED) and the increase of humidity, gas flow rate and toluene concentration, or catalyst introduction. Among the four kinds of catalysts, the CuO catalyst showed the best performance in NOx suppression. The MnOx catalyst exhibited the lowest concentration of O3 and highest CO2 selectivity but the highest concentration of NOx. A possible pathway for NOx production in DBD was discussed. The contributions of oxygen active species and hydroxyl radicals are dominant in NOx suppression. PMID:25662254

  15. Butanol formation from gaseous substrates.

    PubMed

    Dürre, Peter

    2016-03-01

    Mostly, butanol is formed as a product by saccharolytic anaerobes, employing the so-called ABE fermentation (for acetone-butanol-ethanol). However, this alcohol can also be produced from gaseous substrates such as syn(thesis) gas (major components are carbon monoxide and hydrogen) by autotrophic acetogens. In view of economic considerations, a biotechnological process based on cheap and abundant gases such as CO and CO2 as a carbon source is preferable to more expensive sugar or starch fermentation. In addition, any conflict for use of substrates that can also serve as human nutrition is avoided. Natural formation of butanol has been found with, e.g. Clostridium carboxidivorans, while metabolic engineering for butanol production was successful using, e.g. C. ljungdahlii. Production of butanol from CO2 under photoautotrophic conditions was also possible by recombinant DNA construction of a respective cyanobacterial Synechococcus sp. PCC 7942 strain. PMID:26903012

  16. Automated gaseous criteria pollutant audits

    SciTech Connect

    Watson, J.P.

    1998-12-31

    The Quality Assurance Section (QAS) of the California Air Resources Board (CARB) began performing automated gaseous audits of its ambient air monitoring sites in July 1996. The concept of automated audits evolved from the constant streamlining of the through-the-probe audit process. Continual audit van development and the desire to utilize advanced technology to save time and improve the accuracy of the overall audit process also contributed to the concept. The automated audit process is a computer program which controls an audit van`s ambient gas calibration system, isolated relay and analog to digital cards, and a monitoring station`s data logging system. The program instructs the audit van`s gas calibration system to deliver specified audit concentrations to a monitoring station`s instruments through their collection probe inlet. The monitoring station`s responses to the audit concentrations are obtained by the program polling the station`s datalogger through its RS-232 port. The program calculates relevant audit statistics and stores all data collected during an audit in a relational database. Planning for the development of an automated gaseous audit system began in earnest in 1993, when the CARB purchased computerized ambient air calibration systems which could be remotely controlled by computer through their serial ports. After receiving all the required components of the automated audit system, they were individually tested to confirm their correct operation. Subsequently, a prototype program was developed to perform through-the-probe automated ozone audits. Numerous simulated ozone audits documented the program`s ability to control audit equipment and extract data from a monitoring station`s data logging system. The program was later modified to incorporate the capability to perform audits for carbon monoxide, total hydrocarbons, methane, nitrogen dioxide, sulfur dioxide, and hydrogen sulfide.

  17. Gaseous emissions from waste combustion.

    PubMed

    Werther, Joachim

    2007-06-18

    An overview is given on methods and technologies for limiting the gaseous emissions from waste combustion. With the guideline 2000/76/EC recent European legislation has set stringent limits not only for the mono-combustion of waste in specialized incineration plants but also for co-combustion in coal-fired power plants. With increased awareness of environmental issues and stepwise decrease of emission limits and inclusion of more and more substances into the network of regulations a multitude of emission abatement methods and technologies have been developed over the last decades. The result is the state-of-the-art waste incinerator with a number of specialized process steps for the individual components in the flue gas. The present work highlights some new developments which can be summarized under the common goal of reducing the costs of flue gas treatment by applying systems which combine the treatment of several noxious substances in one reactor or by taking new, simpler routes instead of the previously used complicated ones or - in the case of flue gas desulphurisation - by reducing the amount of limestone consumption. Cost reduction is also the driving force for new processes of conditioning of nonhomogenous waste before combustion. Pyrolysis or gasification is used for chemical conditioning whereas physical conditioning means comminution, classification and sorting processes. Conditioning yields a fuel which can be used in power plants either as a co-fuel or a mono-fuel and which will burn there under much better controlled conditions and therefore with less emissions than the nonhomogeneous waste in a conventional waste incinerator. Also for cost reasons, co-combustion of wastes in coal-fired power stations is strongly pressing into the market. Recent investigations reveal that the co-firing of waste can also have beneficial effects on the operating behavior of the boiler and on the gaseous emissions. PMID:17339077

  18. The Role of NADPH Oxidases (NOXs) in Liver Fibrosis and the Activation of Myofibroblasts

    PubMed Central

    Liang, Shuang; Kisseleva, Tatiana; Brenner, David A.

    2016-01-01

    Chronic liver injury, resulted from different etiologies (e.g., virus infection, alcohol abuse, nonalcoholic steatohepatitis (NASH) and cholestasis) can lead to liver fibrosis characterized by the excess accumulation of extracellular matrix (ECM) proteins (e.g., type I collagen). Hepatic myofibroblasts that are activated upon liver injury are the key producers of ECM proteins, contributing to both the initiation and progression of liver fibrosis. Hepatic stellate cells (HSCs) and to a lesser extent, portal fibroblast, are believed to be the precursor cells that give rise to hepatic myofibroblasts in response to liver injury. Although, much progress has been made toward dissecting the lineage origin of myofibroblasts, how these cells are activated and become functional producers of ECM proteins remains incompletely understood. Activation of myofibroblasts is a complex process that involves the interactions between parenchymal and non-parenchymal cells, which drives the phenotypic change of HSCs from a quiescent stage to a myofibroblastic and active phenotype. Accumulating evidence has suggested a critical role of NADPH oxidase (NOX), a multi-component complex that catalyzes reactions from molecular oxygen to reactive oxygen species (ROS), in the activation process of hepatic myofibroblasts. NOX isoforms, including NOX1, NOX2 and NOX4, and NOX-derived ROS, have all been implicated to regulate HSC activation and hepatocyte apoptosis, both of which are essential steps for initiating liver fibrosis. This review highlights the importance of NOX isoforms in hepatic myofibroblast activation and the progression of liver fibrosis, and also discusses the therapeutic potential of targeting NOXs for liver fibrosis and associated hepatic diseases. PMID:26869935

  19. NOx and NOy in the Tropical Marine Boundary Layer

    NASA Astrophysics Data System (ADS)

    Reed, Chris; Evans, Mathew J.; Lee, James D.; Carpenter, Lucy J.; Read, Katie A.; Mendes, Luis N.

    2016-04-01

    Nitrogen oxides (NOx=NO+NO2) and their reservoir species (NOy) play a central role in determining the chemistry of the troposphere. Although their concentrations are low (1-100 ppt) in regions such as the remote marine boundary layer, they have a profound impact on ozone production and the oxidizing capacity. There are very few observations of NOx and NOy in remote oceanic regions due to the technical challenges of measuring such low concentrations, and thus our understanding of this background chemistry is incomplete. Here we present long term measurements of NOx (2006-2015) and more recent measurements of speciated NOy (total peroxyacetyl nitrates, PANs; alkyl nitrates, ANs; nitric acid; and aerosol analogues) made at the Cape Verde Atmospheric Observatory (CVAO; 16° 51' N, 24° 52' W) located in the tropical Atlantic Ocean. We identify potential interferences in the NO2 and NOy measurements and methods to eliminate them. Diurnal and seasonal cycles are interpreted using a box model. We find a complex chemistry with interactions between organic and inorganic chemistry, between the aerosol and gas phase, and between the very local and large scales.

  20. High-Pressure Gaseous Burner (HPGB) Facility Became Operational

    NASA Technical Reports Server (NTRS)

    Nguyen, Quang-Viet

    2003-01-01

    A gas-fueled high-pressure combustion facility with optical access, developed over the last 3 years, is now collecting research data in a production mode. The High-Pressure Gaseous Burner (HPGB) rig at the NASA Glenn Research Center can operate at sustained pressures up to 60 atm with a variety of gaseous fuels and liquid jet fuel. The facility is unique because it is the only continuous-flow, hydrogen-capable 60-atm rig in the world with optical access. It will provide researchers with new insights into flame conditions that simulate the environment inside the ultra-high-pressure-ratio combustion chambers of tomorrow s advanced aircraft engines. The facility provides optical access to the flame zone through four fused-silica optical windows, enabling the calibration of nonintrusive optical diagnostics to measure chemical species and temperature. The data from the HPGB rig enable the validation of numerical codes that simulate gas turbine combustors.

  1. Gaseous sodium sulfate formation in flames and flowing gas environments

    NASA Technical Reports Server (NTRS)

    Stearns, C. A.; Miller, R. A.; Kohl, F. J.; Fryburg, G. C.

    1977-01-01

    Formation of Na2SO4(g) in flames and hot flowing gas systems was studied by high pressure, free-jet expansion, modulated molecular beam mass spectrometric sampling. Fuel-lean CH4-O2 flames doped with SO2, H2O and NaCl yielded the gaseous Na2SO4 molecule in residence times of less than one millisecond. Intermediate species NaSO2(g) and NaSO3(g) were also observed and measured. Composition profiles were obtained for all reaction products. Nonflame flowing gas experiments showed that Na2SO4 and NaSO3 gaseous molecules were formed at 1140 C in mixtures of O2, H2O(g), SO2 and NaCl(g). Experimental results are compared with calculated equilibrium thermodynamic predictions.

  2. Nox4 involvement in TGF-beta and SMAD3-driven induction of the epithelial-to-mesenchymal transition and migration of breast epithelial cells

    PubMed Central

    Boudreau, Howard E.; Casterline, Benjamin W.; Rada, Balazs; Korzeniowska, Agnieszka; Leto, Thomas L.

    2012-01-01

    The epithelial-to-mesenchymal transition (EMT) is the development of increased cell plasticity that occurs normally during wound healing and embryonic development and can be coopted for cancer invasion and metastasis. TGF-beta induces EMT but the mechanism is unclear. Our studies suggest Nox4, a member of the NADPH oxidase (Nox) family, is a source of reactive oxygen species (ROS) affecting cell migration and fibronectin expression, an EMT marker, in normal and metastatic breast epithelial cells. We found TGF-beta induces Nox4 expression (mRNA and protein) and ROS generation in normal (MCF10A) and metastatic (MDA-MB-231) human breast epithelial cells. Conversely, cells expressing a dominant-negative form of Nox4 or Nox4-targeted shRNA showed significantly lower ROS production upon TGF-beta treatment. Expression of a constitutively active TGF-beta receptor type I significantly increased Nox4 promoter activity, mRNA and protein expression, and ROS generation. Nox4 transcriptional regulation by TGF-beta was SMAD3-dependent based on the effect of constitutively active SMAD3 increasing Nox4 promoter activity, whereas dominant-negative SMAD3 or SIS3, a SMAD3-specific inhibitor, had the opposite effect. Furthermore, Nox4 knockdown, dominant-negative Nox4 or SMAD3, or SIS3 blunted TGF-beta induced wound healing and cell migration, whereas cell proliferation was not effected. Our experiments further indicate Nox4 plays a role in TGF-beta regulation of fibronectin mRNA expression, based on the effects of dominant-negative Nox4 in reducing fibronectin mRNA in TGF-beta treated MDA-MB-231and MCF10A cells. Collectively, these data indicate Nox4 contributes to NADPH oxidase-dependent ROS production that may be critical for progression of the EMT in breast epithelial cells, and thereby has therapeutic implications. PMID:22728268

  3. NOX2-dependent regulation of inflammation.

    PubMed

    Singel, Kelly L; Segal, Brahm H

    2016-04-01

    NADPH oxidase (NOX) isoforms together have multiple functions that are important for normal physiology and have been implicated in the pathogenesis of a broad range of diseases, including atherosclerosis, cancer and neurodegenerative diseases. The phagocyte NADPH oxidase (NOX2) is critical for antimicrobial host defence. Chronic granulomatous disease (CGD) is an inherited disorder of NOX2 characterized by severe life-threatening bacterial and fungal infections and by excessive inflammation, including Crohn's-like inflammatory bowel disease (IBD). NOX2 defends against microbes through the direct antimicrobial activity of reactive oxidants and through activation of granular proteases and generation of neutrophil extracellular traps (NETs). NETosis involves the breakdown of cell membranes and extracellular release of chromatin and neutrophil granular constituents that target extracellular pathogens. Although the immediate effects of oxidant generation and NETosis are predicted to be injurious, NOX2, in several contexts, limits inflammation and injury by modulation of key signalling pathways that affect neutrophil accumulation and clearance. NOX2 also plays a role in antigen presentation and regulation of adaptive immunity. Specific NOX2-activated pathways such as nuclear factor erythroid 2-related factor 2 (Nrf2), a transcriptional factor that induces antioxidative and cytoprotective responses, may be important therapeutic targets for CGD and, more broadly, diseases associated with excessive inflammation and injury.

  4. Modelling NOx emissions of single droplet combustion

    NASA Astrophysics Data System (ADS)

    Moesl, Klaus G.; Schwing, Joachim E.; Sattelmayer, Thomas

    2012-02-01

    An approach for modelling and simulation of the generation of nitrogen oxide (NOx) in the gas phase surrounding single burning droplets is presented. Assuming spherical symmetry (no gravity, no forced convection), the governing equations are derived first. Then simplifications are introduced and it is proven that they are appropriate. The influences of the initial droplet diameter, the ambient conditions, and the droplet pre-vapourisation on NOx are investigated. The fuel of choice is n-decane (C10H22) as it resembles kerosene and diesel fuel best, and the complexity of the reaction mechanism is manageable. Combinations of C10H22 mechanisms and well-established NOx kinetics are evaluated in detail and validated for their applicability in the context of this work. The conducted simulations of droplet combustion in an atmosphere of hot exhaust gas show that NOx formation (by mass of fuel) increases linearly with the droplet diameter. There is a trade-off between available oxygen and ambient temperature. Increasing the equivalence ratio of the exhaust gas leads to higher NOx emissions in the very lean regime, but to lower emissions if the equivalence ratio exceeds 0.85. Pre-vapourisation of fuel at ambient conditions becomes beneficial with respect to NOx emissions only if the degree of vapourisation is above a minimum limit. If less fuel is vapourised before ignition, the NOx emissions remain almost unaffected.

  5. Oxidation of Са2+-Binding Domain of NADPH Oxidase 5 (NOX5): Toward Understanding the Mechanism of Inactivation of NOX5 by ROS

    PubMed Central

    Petrushanko, Irina Yu; Lobachev, Vladimir M.; Kononikhin, Alexey S.; Makarov, Alexander A.; Devred, Francois; Kovacic, Hervé; Kubatiev, Aslan A.; Tsvetkov, Philipp O.

    2016-01-01

    NOX5 protein, one of the most active generators of reactive oxygen species (ROS), plays an important role in many processes, including regulation of cell growth, death and differentiation. Because of its central role in ROS generation, it needs to be tightly regulated to guarantee cellular homeostasis. Contrary to other members of NADPH-oxidases family, NOX5 has its own regulatory calcium-binding domain and thus could be activated directly by calcium ions. While several mechanisms of activation have been described, very little is known about the mechanisms that could prevent the overproduction of ROS by NOX5. In the present study using calorimetric methods and circular dichroism we found that oxidation of cysteine and methionine residues of NOX5 decreases binding of Ca2+ ions and perturbs both secondary and tertiary structure of protein. Our data strongly suggest that oxidation of calcium-binding domain of NOX5 could be implicated in its inactivation, serving as a possible defense mechanism against oxidative stress. PMID:27391469

  6. Oxidation of Са2+-Binding Domain of NADPH Oxidase 5 (NOX5): Toward Understanding the Mechanism of Inactivation of NOX5 by ROS.

    PubMed

    Petrushanko, Irina Yu; Lobachev, Vladimir M; Kononikhin, Alexey S; Makarov, Alexander A; Devred, Francois; Kovacic, Hervé; Kubatiev, Aslan A; Tsvetkov, Philipp O

    2016-01-01

    NOX5 protein, one of the most active generators of reactive oxygen species (ROS), plays an important role in many processes, including regulation of cell growth, death and differentiation. Because of its central role in ROS generation, it needs to be tightly regulated to guarantee cellular homeostasis. Contrary to other members of NADPH-oxidases family, NOX5 has its own regulatory calcium-binding domain and thus could be activated directly by calcium ions. While several mechanisms of activation have been described, very little is known about the mechanisms that could prevent the overproduction of ROS by NOX5. In the present study using calorimetric methods and circular dichroism we found that oxidation of cysteine and methionine residues of NOX5 decreases binding of Ca2+ ions and perturbs both secondary and tertiary structure of protein. Our data strongly suggest that oxidation of calcium-binding domain of NOX5 could be implicated in its inactivation, serving as a possible defense mechanism against oxidative stress. PMID:27391469

  7. Process for exchanging hydrogen isotopes between gaseous hydrogen and water

    DOEpatents

    Hindin, Saul G.; Roberts, George W.

    1980-08-12

    A process for exchanging isotopes of hydrogen, particularly tritium, between gaseous hydrogen and water is provided whereby gaseous hydrogen depeleted in tritium and liquid or gaseous water containing tritium are reacted in the presence of a metallic catalyst.

  8. 40 CFR 97.82 - NOX authorized account representative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins § 97.82 NOX authorized account representative. A unit for which an application for a...

  9. 40 CFR 96.82 - NOX authorized account representative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.82 NOX authorized account representative. A unit for which...

  10. 40 CFR 96.82 - NOX authorized account representative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.82 NOX authorized account representative. A unit for which...

  11. 40 CFR 97.82 - NOX authorized account representative.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins § 97.82 NOX authorized account representative. A unit for which an application for a...

  12. 40 CFR 96.82 - NOX authorized account representative.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.82 NOX authorized account representative. A unit for which...

  13. 40 CFR 96.82 - NOX authorized account representative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.82 NOX authorized account representative. A unit for which...

  14. 40 CFR 97.82 - NOX authorized account representative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins. § 97.82 NOX authorized account representative. A unit for which an application for a...

  15. 40 CFR 96.53 - Recordation of NOX allowance allocations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... allocated to an allocation set-aside. (c) Serial numbers for allocated NO X allowances. When allocating NOX... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Recordation of NOX allowance... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR...

  16. 40 CFR 96.82 - NOX authorized account representative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.82 NOX authorized account representative. A unit for which...

  17. 40 CFR 97.82 - NOX authorized account representative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins § 97.82 NOX authorized account representative. A unit for which an application for a...

  18. 40 CFR 97.82 - NOX authorized account representative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins. § 97.82 NOX authorized account representative. A unit for which an application for a...

  19. Rho Kinase ROCK2 Mediates Acid-Induced NADPH Oxidase NOX5-S Expression in Human Esophageal Adenocarcinoma Cells

    PubMed Central

    Cao, Weibiao

    2016-01-01

    Mechanisms of the progression from Barrett’s esophagus (BE) to esophageal adenocarcinoma (EA) are not fully understood. We have shown that NOX5-S may be involved in this progression. However, how acid upregulates NOX5-S is not well known. We found that acid-induced increase in NOX5-S expression was significantly decreased by the Rho kinase (ROCK) inhibitor Y27632 in BE mucosal biopsies and FLO-1 EA cells. In addition, acid treatment significantly increased the Rho kinase activity in FLO-1 cells. The acid-induced increase in NOX5-S expression and H2O2 production was significantly decreased by knockdown of Rho kinase ROCK2, but not by knockdown of ROCK1. Conversely, the overexpression of the constitutively active ROCK2, but not the constitutively active ROCK1, significantly enhanced the NOX5-S expression and H2O2 production. Moreover, the acid-induced increase in Rho kinase activity and in NOX5-S mRNA expression was blocked by the removal of calcium in both FLO-1 and OE33 cells. The calcium ionophore A23187 significantly increased the Rho kinase activity and NOX5-S mRNA expression. We conclude that acid-induced increase in NOX5-S expression and H2O2 production may depend on the activation of ROCK2, but not ROCK1, in EA cells. The acid-induced activation of Rho kinase may be mediated by the intracellular calcium increase. It is possible that persistent acid reflux present in BE patients may increase the intracellular calcium, activate ROCK2 and thereby upregulate NOX5-S. High levels of reactive oxygen species derived from NOX5-S may cause DNA damage and thereby contribute to the progression from BE to EA. PMID:26901778

  20. Influence of Ceria on the NOx Storage/Reduction Behavior of Lean NOx Trap Catalysts

    SciTech Connect

    Ji, Yaying; Choi, Jae-Soon; Toops, Todd J; Crocker, Dr. Mark; Naseri, Mojghan

    2008-01-01

    The effect of La2O3-stabilized ceria incorporation on the functioning of fully formulated lean NOx trap catalysts was investigated. Monolithic catalysts were prepared, corresponding to loadings of 0, 50 and 100 g CeO2/L, together with a catalyst containing 100 g/L of ceria-zirconia (Ce0.7Zr0.3O2). Loadings of the other main components (Pt, Rh and BaO) were held constant. Catalyst evaluation was performed on a bench flow reactor under simulated diesel exhaust conditions, employing NOx storage/reduction cycles. NOx storage efficiency in the temperature range 150-350 C was observed to increase with ceria loading, resulting in higher NOx conversion levels. At 150 C, high rich phase NOx slip was observed for all of the catalysts, resulting from an imbalance in the rates of nitrate decomposition and NOx reduction. Optimal NOx conversion was obtained in the range 250-350 C for all the catalysts, while at 450 C high rich phase NOx slip from the most highly loaded ceria-containing catalyst resulted in lower NOx conversion than for the ceria-free formulation. N2O was the major NOx reduction product at 150 C over all of the catalysts, although low NOx conversion levels limited the N2O yield. At higher temperatures N2 was the main product of NOx reduction, although NH3 formation was also observed. Selectivity to NH3 decreased with increasing ceria loading, indicating that NH3 is consumed by reaction with stored oxygen in the rear of the catalyst.

  1. 40 CFR 96.12 - Changing the NOX authorized account representative and the alternate NOX authorized account...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Changing the NOX authorized account representative and the alternate NOX authorized account representative; changes in the owners and operators. 96... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION...

  2. 40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass emissions. 75.71 Section 75.71 Protection...

  3. 40 CFR 96.12 - Changing the NOX authorized account representative and the alternate NOX authorized account...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Changing the NOX authorized account representative and the alternate NOX authorized account representative; changes in the owners and operators. 96... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION...

  4. 40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and heat input for the purpose of calculating NOX mass emissions. 75.71 Section 75.71 Protection of... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass emissions. (a) Coal-fired units. The owner or operator of a...

  5. Effect of reductive treatments on Pt behavior and NOx storage in lean NOx trap catalysts

    SciTech Connect

    Wang, Xianqin; Kim, Do Heui; Kwak, Ja Hun; Wang, Chong M.; Szanyi, Janos; Peden, Charles HF

    2011-10-01

    Lean NOx trap (LNT) catalysts represent a promising approach to meet increasingly stringent NOx emission regulations on diesel and other lean-burn engines. Pt material properties, including dispersion and particle size, are known to be important factors in determining NOx uptake performance, since Pt provides active sites for NO oxidation to NO2 necessary for storing NOx as nitrates, and for the reduction of nitrates to N2. In this work, the physicochemical properties of Pt in Pt-BaO/Al2O3 LNT catalysts, such as the Pt accessible surface area and particle size, were investigated by using various tools, such as irreversible volumetric H2 chemisorption, high resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD), following successive reductive treatments at elevated temperatures. NOx uptake activities were also measured to establish a relationship between the properties of Pt and NOx storage following identical high-temperature reductive treatments. We find that the reductive treatments of Pt-BaO/Al2O3 lean NOx trap catalysts at temperatures up to 500 ºC promote a significant increase in NOx uptake explained, in part, by an induced close interaction between Pt and BaO phases in the catalyst, thus enabling facilitation of the NOx storage process.

  6. Ammonia-Free NOx Control System

    SciTech Connect

    Song Wu; Zhen Fan; Richard G. Herman

    2004-12-31

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the October 1 to December 30, 2004 time period.

  7. Ammonia-Free NOx Control System

    SciTech Connect

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2004-09-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the July 1 to September 30, 2004 time period.

  8. NOx Formation in a Premixed Syngas Flame

    SciTech Connect

    Yilmaz, S.L.; Givi, P.; Strakey, P.; Casleton, K.

    2006-11-01

    Reduction of NOx is a subject of significant current interest in stationary gas turbines. The objective of this study is to examine the effects of turbulence on non-thermal NOx formation in a syngas flame. This is archived by a detailed parametric study via PDF simulations of a partially stirred reactor and a dumped axisymmetric premixed flame. Several different detailed and reduced kinetics schemes are considered. The simulated results demonstrate the strong dependence of combustion process on turbulence. It is shown that the amount of NOx formation is significantly influenced by the inlet conditions. That is, the turbulence intensity can be tweaked to attain optimal ultra-low NOx emissions at a given temperature.

  9. Ammonia-Free NOx Control System

    SciTech Connect

    Zhen Fan; Song Wu; Richard G. Herman

    2004-06-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the April 1 to June 30, 2004 time period.

  10. Ammonia-Free NOx Control System

    SciTech Connect

    S. Wu; Z. Fan; R. Herman

    2004-03-31

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the January 1 to March 31, 2004 time period.

  11. Gaseous phase coal surface modification

    SciTech Connect

    Okoh, J.M.; Pinion, J.; Thiensatit, S.

    1992-05-07

    In this report, we present an improved, feasible and potentially cost effective method of cleaning and beneficiating ultrafine coal. Increased mechanization of mining methods and the need towards depyritization, and demineralization have led to an increase in the quantity of coal fines generated in recent times. For example, the amount of {minus}100 mesh coal occurring in coal preparation plant feeds now typically varies from 5 to 25% of the total feed. Environmental constraints coupled with the greatly increased cost of coal have made it increasingly important to recover more of these fines. Our method chemically modifies the surface of such coals by a series of gaseous phase treatments employing Friedel-Crafts reactions. By using olefins (ethene, propene and butene) and hydrogen chloride catalyst at elevated temperature, the surface hydrophobicity of coal is enhanced. This increased hydrophobicity is manifest in surface phenomena which reflect conditions at the solid/liquid interphase (zeta potential) and those which reflect conditions at the solid/liquid/gas interphases (contact angle, wettability and floatability).

  12. Combination free-electron and gaseous laser

    SciTech Connect

    Brau, C.A.; Rockwood, S.D.; Stein, W.E.

    1981-06-08

    A multiple laser having one or more gaseous laser stages and one or more free electron stages is described. Each of the free electron laser stages is sequentially pumped by a microwave linear accelerator. Subsequently, the electron beam is directed through a gaseous laser, in the preferred embodiment, and in an alternative embodiment, through a microwave accelerator to lower the energy level of the electron beam to pump one or more gaseous lasers. The combination laser provides high pulse repetition frequencies, on the order of 1 kHz or greater, high power capability, high efficiency, and tunability in the synchronous production of multiple beams of coherent optical radiation.

  13. Combination free electron and gaseous laser

    DOEpatents

    Brau, Charles A.; Rockwood, Stephen D.; Stein, William E.

    1980-01-01

    A multiple laser having one or more gaseous laser stages and one or more free electron stages. Each of the free electron laser stages is sequentially pumped by a microwave linear accelerator. Subsequently, the electron beam is directed through a gaseous laser, in the preferred embodiment, and in an alternative embodiment, through a microwave accelerator to lower the energy level of the electron beam to pump one or more gaseous lasers. The combination laser provides high pulse repetition frequencies, on the order of 1 kHz or greater, high power capability, high efficiency, and tunability in the synchronous production of multiple beams of coherent optical radiation.

  14. Chemical Analysis of NOx Removal Under Different Reduced Electric Fields

    NASA Astrophysics Data System (ADS)

    Haddouche, A.; Lemerini, M.

    2015-07-01

    This work presents a chemical kinetic analysis of different species involved in nitrogen-oxygen mixed gas induced by stationary corona discharge at room temperature and atmospheric pressure. This study takes into account twenty different chemical species participating in one hundred and seventy selected chemical reactions. The reaction rate coefficients are taken from the literature, and the density is analyzed by the continuity equation without the diffusion term. A large number of investigations considered the removal of NOx showing the effects of N, O and O3 radicals. The aim of the present simulation is to complete these studies by analysing various plasma species under different reduced electric fields in the range of 100-200 Td (1 Td=10-21 V·m2). In particular, we analyze the time evolution of depopulation (10-9-10-3 s) of NOx. We have found that the depopulation rate of NO and NO2 is substantially affected by the rise of reduced electric field as it grows from 100 Td to 200 Td. This allows us to ascertain the important role played by the reduced electric field.

  15. Correlating Engine NOx Emission with Biodiesel Composition

    NASA Astrophysics Data System (ADS)

    Jeyaseelan, Thangaraja; Mehta, Pramod Shankar

    2016-06-01

    Biodiesel composition comprising of saturated and unsaturated fatty acid methyl esters has a significant influence on its properties and hence the engine performance and emission characteristics. This paper proposes a comprehensive approach for composition-property-NOx emission analysis for biodiesel fuels and highlights the pathways responsible for such a relationship. Finally, a procedure and a predictor equation are developed for the assessment of biodiesel NOx emission from its composition details.

  16. Impact of chamber wall loss of gaseous organic compounds on secondary organic aerosol formation: Explicit modeling of SOA formation from alkane and alkene oxidation

    DOE PAGES

    La, Y. S.; Camredon, M.; Ziemann, P. J.; Valorso, R.; Matsunaga, A.; Lannuque, V.; Lee-Taylor, J.; Hodzic, A.; Madronich, S.; Aumont, B.

    2016-02-08

    Recent studies have shown that low volatility gas-phase species can be lost onto the smog chamber wall surfaces. Although this loss of organic vapors to walls could be substantial during experiments, its effect on secondary organic aerosol (SOA) formation has not been well characterized and quantified yet. Here the potential impact of chamber walls on the loss of gaseous organic species and SOA formation has been explored using the Generator for Explicit Chemistry and Kinetics of the Organics in the Atmosphere (GECKO-A) modeling tool, which explicitly represents SOA formation and gas–wall partitioning. The model was compared with 41 smog chambermore » experiments of SOA formation under OH oxidation of alkane and alkene series (linear, cyclic and C12-branched alkanes and terminal, internal and 2-methyl alkenes with 7 to 17 carbon atoms) under high NOx conditions. Simulated trends match observed trends within and between homologous series. The loss of organic vapors to the chamber walls is found to affect SOA yields as well as the composition of the gas and the particle phases. Simulated distributions of the species in various phases suggest that nitrates, hydroxynitrates and carbonylesters could substantially be lost onto walls. The extent of this process depends on the rate of gas–wall mass transfer, the vapor pressure of the species and the duration of the experiments. Furthermore, this work suggests that SOA yields inferred from chamber experiments could be underestimated up a factor of 2 due to the loss of organic vapors to chamber walls.« less

  17. Simulating near-road reactive dispersion of gaseous air pollutants using a three-dimensional Eulerian model.

    PubMed

    Kota, Sri Harsha; Ying, Qi; Zhang, Yunlong

    2013-06-01

    In this study, the TAMNROM-3D model, a 3D Eulerian near-road air quality model with vehicle induced turbulence parameterization and a MOVES based emission preprocessor, is tested using near-road gaseous pollutants data collected near a rural freeway with 34% heavy duty vehicle traffic. Exhaust emissions of gasses from the vehicles are estimated using a lumped vehicle classification scheme based on the number of vehicle axles and the default county-level MOVES vehicle fleet database. The predicted dilution of CO and NOx in the downwind direction agrees well with observation, although the total NOx emission has to be scaled to 85% of its original emission rate estimated by the MOVES model. Using the atmospheric turbulent diffusion coefficient parameterization of Degrazia et al. (2000) with variable horizontal turbulent diffusion coefficient (Kxx) leads to slightly better predictions than a traditional non-height-dependent Kxx parameterization. The NO2 concentrations can be better predicted when emission of total NOx is split into NO and NO2 using the NO2 to NOx ratio of 29% measured near the road. Simulations using the SAPRC99 photochemical mechanism do not show significant changes in the predicted NO and NO2 concentrations near the road compared to simulations using a simple three-reaction mechanism that involves only NOx and O3. A regional air quality simulation in Houston, Texas during a high O3 episode in August 2000 shows that using the NO2 to NOx ratio of 29% instead of the traditional 5% leads to as much as 6ppb increase in 8-h O3 predictions.

  18. OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

    SciTech Connect

    David R. Thompson; Lawrence E. Bool; Jack C. Chen

    2004-04-01

    Conventional wisdom says adding oxygen to a combustion system enhances product throughput, system efficiency, and, unless special care is taken, increases NOx emissions. This increase in NOx emissions is typically due to elevated flame temperatures associated with oxygen use leading to added thermal NOx formation. Innovative low flame temperature oxy-fuel burner designs have been developed and commercialized to minimize both thermal and fuel NOx formation for gas and oil fired industrial furnaces. To be effective these systems require close to 100% oxy-fuel combustion and the cost of oxygen is paid for by fuel savings and other benefits. For applications to coal-fired utility boilers at the current cost of oxygen, however, it is not economically feasible to use 100% oxygen for NOx control. In spite of this conventional wisdom, Praxair and its team members, in partnership with the US Department of Energy National Energy Technology Laboratory, have developed a novel way to use oxygen to reduce NOx emissions without resorting to complete oxy-fuel conversion. In this concept oxygen is added to the combustion process to enhance operation of a low NOx combustion system. Only a small fraction of combustion air is replaced with oxygen in the process. By selectively adding oxygen to a low NOx combustion system it is possible to reduce NOx emissions from nitrogen-containing fuels, including pulverized coal, while improving combustion characteristics such as unburned carbon. A combination of experimental work and modeling was used to define how well oxygen enhanced combustion could reduce NOx emissions. The results of this work suggest that small amounts of oxygen replacement can reduce the NOx emissions as compared to the air-alone system. NOx emissions significantly below 0.15 lbs/MMBtu were measured. Oxygen addition was also shown to reduce carbon in ash. Comparison of the costs of using oxygen for NOx control against competing technologies, such as SCR, show that this

  19. Role of Nox2 and p22phox in Persistent Postoperative Hypertension in Aldosterone-Producing Adenoma Patients after Adrenalectomy.

    PubMed

    Geng, Xiaojing; Yan, Li; Dong, Jun; Liang, Ying; Deng, Yajuan; Li, Ting; Luo, Tongfeng; Lin, Hailun; Zhang, Shaoling

    2016-01-01

    Adrenal aldosterone-producing adenoma (APA), producing the salt-retaining hormone aldosterone, commonly causes secondary hypertension, which often persists after unilateral adrenalectomy. Although persistent hypertension was correlated with residual hormone aldosterone, the in vivo mechanism remains unclear. NADPH oxidase is the critical cause of aldosterone synthesis in vitro. Nox2 and p22phox comprise the NADPH oxidase catalytic core, serving to initiate a reactive oxygen species (ROS) cascade that may participate in the pathology. mRNAs of seven NADPH oxidase isoforms in APA were evaluated by RT-PCR and Q-PCR and their proteins by immunohistochemistry and Western blotting. NADPH oxidase activity was also detected. Nox2 and p22phox were especially abundant in APA. Particularly higher Nox2 and p22phox gene and protein levels were seen in APA than controls. Significant correlations between Nox2 mRNA and aldosterone synthase (CYP11B2) mRNA (R = 0.66, P < 0.01) and Nox2 protein and baseline plasma aldosterone concentration (PAC) (R = 0.503, P < 0.01) were detected in APA; however, none were found between p22phox mRNA, CYP11B2 mRNA, p22phox protein, and baseline PAC. Importantly, we found that Nox2 localized specifically in hyperplastic zona glomerulosa cells. In conclusion, our results highlight that Nox2 and p22phox may be directly involved in pathological aldosterone production and zona glomerulosa cell proliferation after APA resection. PMID:27057164

  20. The Expression of NOX4 in Smooth Muscles of Small Airway Correlates with the Disease Severity of COPD

    PubMed Central

    2016-01-01

    Airway smooth muscle (ASM) remodeling is a hallmark in chronic obstructive pulmonary disease (COPD), and nicotinamide-adenine dinucleotide phosphate (NADPH) oxidases (NOXs) produced reactive oxygen species (ROS) play a crucial role in COPD pathogenesis. In the present study, the expression of NOX4 and its correlation with the ASM hypertrophy/hyperplasia, clinical pulmonary functions, and the expression of transforming growth factor β (TGF-β) in the ASM of COPD small airways were investigated by semiquantitative morphological and/or immunohistochemistry staining methods. The results showed that an elevated expression of NOX4 and TGF-β, along with an increased volume of ASM mass, was found in the ASM of small airways in COPD patients. The abundance of NOX4 protein in the ASM was increased with disease severity and inversely correlated with the pulmonary functions in COPD patients. In addition, the expression of NOX4 and ASM marker α-SMA was colocalized, and the increased NOX4 expression was found to accompany an upregulated expression of TGF-β in the ASM of small airways of COPD lung. These results indicate that NOX4 may be a key regulator in ASM remodeling of small airway, in part through a mechanism interacting with TGF-β signaling in the pathogenesis of COPD, which warrants further investigation. PMID:27656649

  1. The Expression of NOX4 in Smooth Muscles of Small Airway Correlates with the Disease Severity of COPD

    PubMed Central

    2016-01-01

    Airway smooth muscle (ASM) remodeling is a hallmark in chronic obstructive pulmonary disease (COPD), and nicotinamide-adenine dinucleotide phosphate (NADPH) oxidases (NOXs) produced reactive oxygen species (ROS) play a crucial role in COPD pathogenesis. In the present study, the expression of NOX4 and its correlation with the ASM hypertrophy/hyperplasia, clinical pulmonary functions, and the expression of transforming growth factor β (TGF-β) in the ASM of COPD small airways were investigated by semiquantitative morphological and/or immunohistochemistry staining methods. The results showed that an elevated expression of NOX4 and TGF-β, along with an increased volume of ASM mass, was found in the ASM of small airways in COPD patients. The abundance of NOX4 protein in the ASM was increased with disease severity and inversely correlated with the pulmonary functions in COPD patients. In addition, the expression of NOX4 and ASM marker α-SMA was colocalized, and the increased NOX4 expression was found to accompany an upregulated expression of TGF-β in the ASM of small airways of COPD lung. These results indicate that NOX4 may be a key regulator in ASM remodeling of small airway, in part through a mechanism interacting with TGF-β signaling in the pathogenesis of COPD, which warrants further investigation.

  2. Direct evidence of a role for Nox2 in superoxide production, reduced nitric oxide bioavailability, and early atherosclerotic plaque formation in ApoE-/- mice.

    PubMed

    Judkins, Courtney P; Diep, Henry; Broughton, Brad R S; Mast, Anja E; Hooker, Elizabeth U; Miller, Alyson A; Selemidis, Stavros; Dusting, Gregory J; Sobey, Christopher G; Drummond, Grant R

    2010-01-01

    The Nox family NADPH oxidases are reactive oxygen species (ROS)-generating enzymes that are strongly implicated in atherogenesis. However, no studies have examined which Nox isoform(s) are involved. Here we investigated the role of the Nox2-containing NADPH oxidase in atherogenesis in apolipoprotein E-null (ApoE(-/-)) mice. Wild-type (C57Bl6/J), ApoE(-/-), and Nox2(-/y)/ApoE(-/-) mice were maintained on a high-fat (21%) diet from 5 wk of age until they were 12 or 19 wk old. Mice were euthanized and their aortas removed for measurement of Nox2 expression (Western blot analysis and immunohistochemistry), ROS production (L012-enhanced chemiluminescence), nitric oxide (NO) bioavailability (contractions to N(omega)-nitro-L-arginine), and atherosclerotic plaque development along the aorta and in the aortic sinus. Nox2 expression was upregulated in the aortic endothelium of ApoE(-/-) mice before the appearance of lesions, and this was associated with elevated ROS levels. Within developing plaques, macrophages were also a prominent source of Nox2. The absence of Nox2 in Nox2(-/y)/ApoE(-/-) double-knockout mice had minimal effects on plasma lipids or lesion development in the aortic sinus in animals up to 19 wk of age. However, an en face examination of the aorta from the arch to the iliac bifurcation revealed a 50% reduction in lesion area in Nox2(-/y)/ApoE(-/-) versus ApoE(-/-) mice, and this was associated with a marked decrease in aortic ROS production and an increased NO bioavailability. In conclusion, this is the first demonstration of a role for Nox2-NADPH oxidase in vascular ROS production, reduced NO bioavailability, and early lesion development in ApoE(-/-) mice, highlighting this Nox isoform as a potential target for future therapies for atherosclerosis. PMID:19837950

  3. Molecular targeting of NOX4 for neuropathic pain after traumatic injury of the spinal cord.

    PubMed

    Im, Y B; Jee, M K; Choi, J I; Cho, H T; Kwon, O H; Kang, S K

    2012-11-15

    Neuropathic pain is a well-known type of chronic pain caused by damage to the nervous system. Until recently, many researchers have primarily focused on identifying cellular or chemical sources of neuropathic pain or have approached neuropathic pain via the basis of biological study. We investigated whether both mmu-mir-23b (miR23b) and NADPH oxidase 4 (NOX4) antibody infusion can alleviate neuropathic pain by compensating for abnormally downregulated miR23b via reducing the expression of its target gene, NOX4, a reactive oxygen species (ROS) family member overexpressed in neuropathic pain. Ectopic miR23b expression effectively downregulated NOX4 and finally normalized glutamic acid decarboxylase 65/67 expression. Moreover, animals with neuropathic pain showed significantly improved paw withdrawal thresholds (PWTs) following miR23b infusion. Normalizing miR23b expression in tissue lesions, caused by neuropathic pain induction, reduced inflammatory mediators and increased several ROS scavengers. Moreover, γ-aminobutyric acid (GABA)ergic neurons coexpressed suboptimal levels of miR23b and elevated NOX4/ROS after pain induction at the cellular level. MiR23b finally protects GABAergic neurons against ROS/p38/c-Jun N-terminal kinase (JNK)-mediated apoptotic death. By evaluating the functional behavior of mice receiving pain/miR23b, normal/anti-miR23b, anti-miR23b/si-NOX4, pain/NOX4 antibody, pain/ascorbic acid, and pain/ascorbic acid/NOX4 antibody, the positive role of miR23b and the negative role of NOX4 in neuropathic pain were confirmed. Based on this study, we conclude that miR23b has a crucial role in the amelioration of neuropathic pain in injured spinal cord by inactivating its target gene, NOX4, and protection of GABAergic neurons from cell death. We finally suggest that infusion of miR23b and NOX4 antibody may provide attractive diagnostic and therapeutic resources for effective pain modulation in neuropathic pain.

  4. Production of gaseous radiotracers for industrial applications.

    PubMed

    Sharma, V K; Pant, H J; Goswami, Sunil; Jagadeesan, K C; Anand, S; Chitra, S; Rana, Y S; Sharma, Archana; Singh, Tej; Gujar, H G; Dash, Ashutosh

    2016-10-01

    This paper describes prerequisite tests, analysis and the procedure for irradiation of gaseous targets and production of gaseous radioisotopes i.e. argon-41 ((41)Ar) and krypton-79 ((79)Kr) in a 100MWTh DHRUVA reactor located at Bhabha Atomic Research Center (BARC), Trombay, Mumbai, India. The produced radioisotopes will be used as radiotracers for tracing gas phase in industrial process systems. Various details and prequalification tests required for irradiation of gaseous targets are discussed. The procedure for regular production of (41)Ar and (79)Kr, and assay of their activity were standardized. Theoretically estimated and experimentally produced amounts of activities of the two radioisotopes, irradiated at identical conditions, were compared and found to be in good agreement. Based on the various tests, radiological safety analysis and standardization of the irradiation procedure, necessary approval was obtained from the competent reactor operating and safety authorities for regular production of gaseous radiotracers in DHRUVA reactor. PMID:27518216

  5. Comparison of gaseous exhaust indices of the F109 turbofan using three different blends of petroleum-based Jet-A and camelina-based Jet-A

    NASA Astrophysics Data System (ADS)

    Kozak, Brian John

    This research project focused on the collection and comparison of gaseous exhaust emissions of the F109 turbofan engine using petroleum-based Jet-A and two different blends of camelina-based Jet-A. Simulated landing and takeoff cycles were used to collect gaseous exhaust emissions. Unburned hydrocarbon (HC), nitrogen oxide (NOx), and carbon moNOxide (CO) exhaust indices (EIm) were calculated using ICAO Annex 16 Volume II formulae. Statistical analyses were performed on the Elm data. There was no significant difference in HC EIm and CO EI m among the three fuels at takeoff thrust. There were significant differences among the fuels for NOx EIm. 50% Jet-A 50% camelina produced the highest NOx EIm, then 75% Jet-A 25% camelina and finally Jet-A. At climb thrust, both blends of camelina fuel produced higher NOx EIm but no difference in CO EIm and HC EIm as Jet-A. At approach thrust, both blends of camelina fuel produced higher NOx EIm, lower CO EIm, and no difference in HC EIm as Jet-A. At idle thrust, there was no significant difference among the fuels for NOx EIm. There were significant differences among the fuels for HC EIm. Jet-A and 50% Jet-A 50% both produced higher HC EIm as 75% Jet-A 25% camelina. There were significant differences among the fuels for CO EI m. Jet-A produced the highest CO EIm, then 75% Jet-A 25% camelina and finally 50% Jet-A 50% camelina.

  6. Lean NOx Trap Modeling in Vehicle Systems Simulations

    SciTech Connect

    Gao, Zhiming; Chakravarthy, Veerathu K; Daw, C Stuart; Conklin, Jim

    2010-09-01

    A one-dimensional model for simulating lean NOx trap (LNT) performance is developed and validated using both steady state cycling data and transient data from FTP testing cycles. The model consists of the conservation equations for chemical species and energy in the bulk flow, energy of the solid walls, O2 storage and NOx storage (in the form of nitrites and nitrates). Nitrites and nitrates are formed by diffusion of NO and NO2, respectively, into sorbent particles (assumed to be hemi-spherical in shape) along with O2 and their formation rates are controlled by chemical kinetics as well as solid-phase diffusion rates of NOx species. The model also accounts for thermal aging and sulfation of LNTs. Empirical correlations are developed on the basis of published experimental data to capture these effects. These empirical correlations depend on total mileage for which the LNT has been in use, the mileage accumulated since the last desulfation event in addition to the freshly degreened catalyst characteristics. The model has been used in studies of vehicle systems (integration, performance etc.) including hybrid powertrain configurations. Since the engines in hybrid vehicles turn on and off multiple number of times during single drive cycles, the exhaust systems may encounter multiple cold start transients. Accurate modeling of catalyst warm-up and cooling is, therefore, very important to simulate LNT performance in such vehicles. For this purpose, the convective heat loss from the LNT to the ambient is modeled using a Nusselt number correlation that includes effects of both forced convection and natural convection (with later being important when vehicle is stationary). Using the model, the fuel penalty associated with operating LNTs on small diesel engine powered car during FTP drive cycles is estimated.

  7. Calcineurin Aβ regulates NADPH oxidase (Nox) expression and activity via nuclear factor of activated T cells (NFAT) in response to high glucose.

    PubMed

    Williams, Clintoria R; Gooch, Jennifer L

    2014-02-21

    Hypertrophy is an adaptive response that enables organs to appropriately meet increased functional demands. Previously, we reported that calcineurin (Cn) is required for glomerular and whole kidney hypertrophy in diabetic rodents (Gooch, J. L., Barnes, J. L., Garcia, S., and Abboud, H. E. (2003). Calcineurin is activated in diabetes and is required for glomerular hypertrophy and ECM accumulation. Am. J. Physiol. Renal Physiol. 284, F144-F154; Reddy, R. N., Knotts, T. L., Roberts, B. R., Molkentin, J. D., Price, S. R., and Gooch, J. L. (2011). Calcineurin Aβ is required for hypertrophy but not matrix expansion in the diabetic kidney. J. Cell Mol. Med. 15, 414-422). Because studies have also implicated the reactive oxygen species-generating enzymes NADPH oxidases (Nox) in diabetic kidney responses, we tested the hypothesis that Nox and Cn cooperate in a common signaling pathway. First, we examined the role of the two main isoforms of Cn in hypertrophic signaling. Using primary kidney cells lacking a catalytic subunit of Cn (CnAα(-/-) or CnAβ(-/-)), we found that high glucose selectively activates CnAβ, whereas CnAα is constitutively active. Furthermore, CnAβ but not CnAα mediates hypertrophy. Next, we found that chronic reactive oxygen species generation in response to high glucose is attenuated in CnAβ(-/-) cells, suggesting that Cn is upstream of Nox. Consistent with this, loss of CnAβ reduces basal expression and blocks high glucose induction of Nox2 and Nox4. Inhibition of nuclear factor of activated T cells (NFAT), a CnAβ-regulated transcription factor, decreases Nox2 and Nox4 expression, whereas NFAT overexpression increases Nox2 and Nox4, indicating that the CnAβ/NFAT pathway modulates Nox. These data reveal that the CnAβ/NFAT pathway regulates Nox and plays an important role in high glucose-mediated hypertrophic responses in the kidney.

  8. Is Nostoc H-NOX an NO sensor or Redox Switch?

    PubMed Central

    Tsai, Ah-Lim; Berka, Vladimir; Martin, Faye; Ma, Xiaolei; Akker, Focco van den; Fabian, Marian; Olson, John S.

    2010-01-01

    Nostoc sp (Ns) H-NOX is a hemeprotein found in symbiotic cyanobacteria, which has ~35% sequence identity and high structural homology to the β subunit of soluble guanylyl cyclase (sGC), suggesting a NO sensing function. However, UV-Vis, EPR, NIR MCD, and ligand binding experiments with ferrous and ferric Ns H-NOX indicate significant functional differences between Ns H-NOX and sGC. (1) After NO binding to sGC, the proximal histidine dissociates from the heme iron, causing a conformational change that triggers activation of sGC. In contrast, formation of pentacoordinate (5c) NO heme occurs to only a limited extent in Ns H-NOX, even at > 1mM NO. (2) Unlike sGC, two different hexacoordinate (6c)-NO complexes are formed in Ns H-NOX with initial and final absorbance peaks at 418 nm and 414 nm, and the conversion rate is linearly dependent on [NO] indicating that a second NO binds transiently to catalyze formation of the 414 nm species. (3) sGC is insensitive to oxygen, and ferric sGC prepared by ferricyanide oxidation has a 5c high-spin heme complex. In contrast, Ns H-NOX autooxidizes in 24 hr if exposed to air and forms a 6c ferric heme complex indicating a major conformational change after oxidation and coordination by a second histidine side chain. Such a large conformational transition suggests that Ns H-NOX could function as either a redox or a NO sensor in the cyanobacterium. PMID:20572679

  9. Methylcholanthrene-Induced Sarcomas Develop Independently from NOX2-Derived ROS

    PubMed Central

    Ligtenberg, Maarten A.; Çınar, Özcan; Holmdahl, Rikard; Mougiakakos, Dimitrios; Kiessling, Rolf

    2015-01-01

    Reactive oxygen species (ROS) produced by the inducible NADPH oxidase type 2 (NOX2) complex are essential for clearing certain infectious organisms but may also have a role in regulating inflammation and immune response. For example, ROS is involved in myeloid derived suppressor cell (MDSC)- and regulatory T cell (Treg) mediated T- and NK-cell suppression. However, abundant ROS produced within the tumor microenvironment, or by the tumor itself may also yield oxidative stress, which can blunt anti-tumor immune responses as well as eventually leading to tumor toxicity. In this study we aimed to decipher the role of NOX2-derived ROS in a chemically (by methylcholanthrene (MCA)) induced sarcoma model. Superoxide production by NOX2 requires the p47phox (NCF1) subunit to organize the formation of the NOX2 complex on the cell membrane. Homozygous mutant mice (NCF1*/*) have a functional loss of their super oxide burst while heterozygous mice (NCF1*/+) retain this key function. Mice harboring either a homo- or a heterozygous mutation were injected intramuscularly with MCA to induce sarcoma formation. We found that NOX2 functionality does not determine tumor incidence in the tested MCA model. Comprehensive immune monitoring in tumor bearing mice showed that infiltrating immune cells experienced an increase in their oxidative state regardless of the NOX2 functionality. While MCA-induced sarcomas where characterized by a Treg and MDSC accumulation, no significant differences could be found between NCF1*/* and NCF1*/+ mice. Furthermore, infiltrating T cells showed an increase in effector-memory cell phenotype markers in both NCF1*/* and NCF1*/+ mice. Tumors established from both NCF1*/* and NCF1*/+ mice were tested for their in vitro proliferative capacity as well as their resistance to cisplatin and radiation therapy, with no differences being recorded. Overall our findings indicate that NOX2 activity does not play a key role in tumor development or immune cell infiltration in

  10. The NOx dependence of bromine chemistry in the Arctic atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Custard, K. D.; Thompson, C. R.; Pratt, K. A.; Shepson, P. B.; Liao, J.; Huey, L. G.; Orlando, J. J.; Weinheimer, A. J.; Apel, E.; Hall, S. R.; Flocke, F.; Mauldin, L.; Hornbrook, R. S.; Pöhler, D.; General, S.; Zielcke, J.; Simpson, W. R.; Platt, U.; Fried, A.; Weibring, P.; Sive, B. C.; Ullmann, K.; Cantrell, C.; Knapp, D. J.; Montzka, D. D.

    2015-03-01

    Arctic boundary layer nitrogen oxides (NOx = NO2 + NO) are naturally produced in and released from the sunlit snowpack and range between 10 to 100 pptv in the remote background surface layer air. These nitrogen oxides have significant effects on the partitioning and cycling of reactive radicals such as halogens and HOx (OH + HO2). However, little is known about the impacts of local anthropogenic NOx emission sources on gas-phase halogen chemistry in the Arctic, and this is important because these emissions can induce large variability in ambient NOx and thus local chemistry. In this study, a zero-dimensional photochemical kinetics model was used to investigate the influence of NOx on the unique springtime halogen and HOx chemistry in the Arctic. Trace gas measurements obtained during the 2009 OASIS (Ocean-Atmosphere-Sea Ice-Snowpack) field campaign at Barrow, AK were used to constrain many model inputs. We find that elevated NOx significantly impedes gas-phase radical chemistry, through the production of a variety of reservoir species, including HNO3, HO2NO2, peroxyacetyl nitrate (PAN), BrNO2, ClNO2 and reductions in BrO and HOBr, with a concomitant, decreased net O3 loss rate. The effective removal of BrO by anthropogenic NOx was directly observed from measurements conducted near Prudhoe Bay, AK during the 2012 Bromine, Ozone, and Mercury Experiment (BROMEX). Thus, while changes in snow-covered sea ice attributable to climate change may alter the availability of molecular halogens for ozone and Hg depletion, predicting the impact of climate change on polar atmospheric chemistry is complex and must take into account the simultaneous impact of changes in the distribution and intensity of anthropogenic combustion sources. This is especially true for the Arctic, where NOx emissions are expected to increase because of increasing oil and gas extraction and shipping activities.

  11. The NOx dependence of bromine chemistry in the Arctic atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Custard, K. D.; Thompson, C. R.; Pratt, K. A.; Shepson, P. B.; Liao, J.; Huey, L. G.; Orlando, J. J.; Weinheimer, A. J.; Apel, E.; Hall, S. R.; Flocke, F.; Mauldin, L.; Hornbrook, R. S.; Pöhler, D.; S., General; Zielcke, J.; Simpson, W. R.; Platt, U.; Fried, A.; Weibring, P.; Sive, B. C.; Ullmann, K.; Cantrell, C.; Knapp, D. J.; Montzka, D. D.

    2015-09-01

    Arctic boundary layer nitrogen oxides (NOx = NO2 + NO) are naturally produced in and released from the sunlit snowpack and range between 10 to 100 pptv in the remote background surface layer air. These nitrogen oxides have significant effects on the partitioning and cycling of reactive radicals such as halogens and HOx (OH + HO2). However, little is known about the impacts of local anthropogenic NOx emission sources on gas-phase halogen chemistry in the Arctic, and this is important because these emissions can induce large variability in ambient NOx and thus local chemistry. In this study, a zero-dimensional photochemical kinetics model was used to investigate the influence of NOx on the unique springtime halogen and HOx chemistry in the Arctic. Trace gas measurements obtained during the 2009 OASIS (Ocean - Atmosphere - Sea Ice - Snowpack) field campaign at Barrow, AK were used to constrain many model inputs. We find that elevated NOx significantly impedes gas-phase halogen radical-based depletion of ozone, through the production of a variety of reservoir species, including HNO3, HO2NO2, peroxyacetyl nitrate (PAN), BrNO2, ClNO2 and reductions in BrO and HOBr. The effective removal of BrO by anthropogenic NOx was directly observed from measurements conducted near Prudhoe Bay, AK during the 2012 Bromine, Ozone, and Mercury Experiment (BROMEX). Thus, while changes in snow-covered sea ice attributable to climate change may alter the availability of molecular halogens for ozone and Hg depletion, predicting the impact of climate change on polar atmospheric chemistry is complex and must take into account the simultaneous impact of changes in the distribution and intensity of anthropogenic combustion sources. This is especially true for the Arctic, where NOx emissions are expected to increase because of increasing oil and gas extraction and shipping activities.

  12. In situ DRIFTs investigation of the reaction mechanism over MnOx-MOy/Ce0.75Zr0.25O2 (M = Fe, Co, Ni, Cu) for the selective catalytic reduction of NOx with NH3

    NASA Astrophysics Data System (ADS)

    Hu, Hang; Zha, Kaiwen; Li, Hongrui; Shi, Liyi; Zhang, Dengsong

    2016-11-01

    A series of MnOx-MOy/Ce0.75Zr0.25O2 (M = Fe, Co, Ni, Cu) catalysts were synthesized by an impregnation method and used for selective catalytic reduction (SCR) of NOx with NH3. The catalytic performances of various MnOx-MOy/Ce0.75Zr0.25O2 catalysts were studied. It was found that MnOx-FeOy/Ce0.75Zr0.25O2 catalyst showed excellent low-temperature activity and a broad temperature window. The catalysts were characterized by N2 adsorption/desorption, X-ray diffraction, X-ray photoelectron spectroscopy and in situ diffuse reflectance infrared transform spectroscopy (DRIFTS). Characterization of the catalyst confirmed the addition of iron oxide can enhance the NO oxidation ability of the catalyst which results in the outstanding low-temperature SCR activity. Meanwhile, iron oxides were well dispersed on catalyst surface which could avoid the agglomeration of active species, contributing to the strong interaction between active species and the support. More importantly, in situ DRIFTS results confirmed that bidentate nitrates are general active species on these catalysts, whereas the reactivity of gaseous NO2 and bridged nitrates got improved because of the addition of Fe.

  13. High-Potential Electrocatalytic O2 Reduction with Nitroxyl / NOx Mediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

    SciTech Connect

    Gerken, James B.; Stahl, Shannon S.

    2015-07-15

    Efficient reduction of O2 to water is a central challenge in energy conversion and aerobic oxidation catalysis. In the present study, we investigate the electrochemical reduction of O2 with soluble organic nitroxyl and nitrogen oxide (NOx) mediators. When used alone, neither organic nitroxyls, such as TEMPO (2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl), nor NOx species, such as sodium nitrite, are effective mediators of electrochemical O2 reduction. The combination of nitroxyl/NOx species, however, mediates sustained O2 reduction at electrochemical potentials of 0.19–0.33 V (vs. Fc/Fc+) in acetonitrile containing trifluoroacetic acid. Mechanistic analysis of the coupled redox reactions supports a process in which the nitrogen oxide catalyst drives aerobic oxidation of a nitroxyl mediator to an oxoammonium species, which then is reduced back to the nitroxyl at the cathode. The electrolysis potential is dictated by the oxoammonium/nitroxyl reduction potential. The high potentials observed with this ORR system benefit from the mechanism-based specificity for four-electron reduction of oxygen to water mediated by NOx species, together with kinetically efficient reduction of oxidized NOx species by TEMPO and other organic nitroxyls. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center, funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  14. High-Potential Electrocatalytic O2 Reduction with Nitroxyl/NOx Mediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

    PubMed Central

    2015-01-01

    Efficient reduction of O2 to water is a central challenge in energy conversion and many aerobic oxidation reactions. Here, we show that the electrochemical oxygen reduction reaction (ORR) can be achieved at high potentials by using soluble organic nitroxyl and nitrogen oxide (NOx) mediators. When used alone, neither organic nitroxyls, such as 2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl (TEMPO), nor NOx species, such as sodium nitrite, are effective ORR mediators. The combination of nitroxyl/NOx species, however, mediates sustained O2 reduction with overpotentials as low as 300 mV in acetonitrile containing trifluoroacetic acid. Mechanistic analysis of the coupled redox reactions supports a process in which the nitrogen oxide catalyst drives aerobic oxidation of a nitroxyl mediator to an oxoammonium species, which then is reduced back to the nitroxyl at the cathode. The electrolysis potential is dictated by the oxoammonium/nitroxyl reduction potential. The overpotentials accessible with this ORR system are significantly lower than widely studied molecular metal-macrocycle ORR catalysts and benefit from the mechanism-based specificity for four-electron reduction of oxygen to water mediated by NOx species, together with kinetically efficient reduction of oxidized NOx species by TEMPO and other organic nitroxyls. PMID:27162977

  15. (1)H, (13)C, (15)N backbone and side-chain resonance assignment of Nostoc sp. C139A variant of the heme-nitric oxide/oxygen binding (H-NOX) domain.

    PubMed

    Alexandropoulos, Ioannis I; Argyriou, Aikaterini I; Marousis, Kostas D; Topouzis, Stavros; Papapetropoulos, Andreas; Spyroulias, Georgios A

    2016-10-01

    The H-NOX (Heme-nitric oxide/oxygen binding) domain is conserved across eukaryotes and bacteria. In human soluble guanylyl cyclase (sGC) the H-NOX domain functions as a sensor for the gaseous signaling agent nitric oxide (NO). sGC contains the heme-binding H-NOX domain at its N-terminus, which regulates the catalytic site contained within the C-terminal end of the enzyme catalyzing the conversion of GTP (guanosine 5'-triphosphate) to GMP (guanylyl monophosphate). Here, we present the backbone and side-chain assignments of the (1)H, (13)C and (15)N resonances of the 183-residue H-NOX domain from Nostoc sp. through solution NMR.

  16. Enhanced Combustion Low NOx Pulverized Coal Burner

    SciTech Connect

    Ray Chamberland; Aku Raino; David Towle

    2006-09-30

    For more than two decades, ALSTOM Power Inc. (ALSTOM) has developed a range of low cost, in-furnace technologies for NOx emissions control for the domestic U.S. pulverized coal fired boiler market. This includes ALSTOM's internally developed TFS 2000 firing system, and various enhancements to it developed in concert with the U.S. Department of Energy (DOE). As of 2004, more than 200 units representing approximately 75,000 MWe of domestic coal fired capacity have been retrofit with ALSTOM low NOx technology. Best of class emissions range from 0.18 lb/MMBtu for bituminous coals to 0.10 lb/MMBtu for subbituminous coals, with typical levels at 0.24 lb/MMBtu and 0.13 lb/MMBtu, respectively. Despite these gains, NOx emissions limits in the U.S. continue to ratchet down for new and existing (retrofit) boiler equipment. If enacted, proposed Clear Skies legislation will, by 2008, require an average, effective, domestic NOx emissions rate of 0.16 lb/MMBtu, which number will be reduced to 0.13 lb/MMBtu by 2018. Such levels represent a 60% and 67% reduction, respectively, from the effective 2000 level of 0.40 lb/MMBtu. Low cost solutions to meet such regulations, and in particular those that can avoid the need for a costly selective catalytic reduction system (SCR), provide a strong incentive to continue to improve low NOx firing system technology to meet current and anticipated NOx control regulations. In light of these needs, ALSTOM, in cooperation with the DOE, is developing an enhanced combustion, low NOx pulverized coal burner which, when integrated with ALSTOM's state-of-the-art, globally air staged low NOx firing systems, will provide a means to achieve less than 0.15 lb/MMBtu NOx at less than 3/4 the cost of an SCR with low to no impact on balance of plant issues when firing a high volatile bituminous coal. Such coals can be more economic to fire than subbituminous or Powder River Basin (PRB) coals, but are more problematic from a NOx control standpoint as existing

  17. Will Euro 6 reduce the NOx emissions of new diesel cars? - Insights from on-road tests with Portable Emissions Measurement Systems (PEMS)

    NASA Astrophysics Data System (ADS)

    Weiss, Martin; Bonnel, Pierre; Kühlwein, Jörg; Provenza, Alessio; Lambrecht, Udo; Alessandrini, Stefano; Carriero, Massimo; Colombo, Rinaldo; Forni, Fausto; Lanappe, Gaston; Le Lijour, Philippe; Manfredi, Urbano; Montigny, Francois; Sculati, Mirco

    2012-12-01

    The nitrogen dioxide (NO2) pollution in urban areas of Europe can be partially attributed to the increasing market penetration of diesel cars that show higher distance-specific nitrogen oxides (NOx) emissions than gasoline cars. The on-road NOx emissions of diesel cars, furthermore, appear to exceed substantially applicable emissions standards. This observation raises concerns that the introduction of more stringent Euro 6 emissions standards in 2014 may not adequately reduce the distance-specific on-road NOx emissions of new diesel cars. We address the existing concerns by analyzing the gaseous emissions of one novel Euro 6 diesel car and six Euro 4-5 diesel cars with Portable Emissions Measurement Systems (PEMS). We find that the average on-road NOx emissions of the Euro 6 car (0.21 ± 0.09 g per kilometer [g km-1]) are considerably lower than those of the Euro 4 cars (0.76 ± 0.12 g km-1) and the Euro 5 cars (0.71 ± 0.30 g km-1). The selective catalytic reduction (SCR) system of the Euro 6 diesel car is suitable to limit NOx emissions during real-world on-road driving. Still, all tested cars, including the Euro 6 diesel car, exceed their NOx emissions standards on the road by 260 ± 130%. This finding suggests that the current type-approval procedure does not adequately capture the on-road NOx emissions of diesel cars. By introducing a complementary emissions test procedure that covers a wide range of normal operating conditions, the European legislative authorities can address this problem and ensure that Euro 6 will indeed deliver an adequate reduction in the NOx emissions of new diesel cars.

  18. In situ FT-IR studies on the mechanism of selective catalytic reduction of NOx by propene over SnO2/Al2O3 catalyst.

    PubMed

    Liu, Zhiming; Woo, Seong Ihl; Lee, Won Su

    2006-12-28

    The mechanism of the selective catalytic reduction (SCR) of NOx by propene over SnO2/Al2O3 catalyst in the presence of oxygen has been investigated using in situ Fourier transform infrared (FT-IR) spectroscopy. In situ IR measurements indicate that acetate and formate, which are the derivatives of the partial oxidation of propene, play a crucial role in the formation of NCO by reacting with the reactive monodentate nitrate species. The resulting NCO species subsequently reacts with NOx to form N2. The presence of oxygen substantially contributes to the partial oxidation of propene and thus shows a promoting effect for the NOx reduction.

  19. NOx reduction Activity over Phosphate-supported Platinum Catalysts with Hydrogen under Oxygen-rich Condition

    NASA Astrophysics Data System (ADS)

    Itoh, M.; Takehara, M.; Saito, M.; Machida, K.

    2011-10-01

    The phosphate supported Pt catalysts (Pt/AlPO4, Pt/CePO4, Pt/CeP2O7, Pt/SnP2O7, Pt/TiP2O7, Pt/Zn3(PO4)2) were prepared by a conventional impregnation method to evaluate their selective catalytic reduction activity of NOx under excess oxygen condition. Among them, good NOx reduction activity was obtained on the Pt/AlPO4 catalyst. Specific adsorption species during the NOx reduction were checked by a diffuse reflectance infrared Fourier transform spectrum (DRIFTs) measurement to examine the reaction mechanism. Also NH3 temperature programmed desorption measurements were performed for all catalysts and their catalytic properties were discussed from the viewpoints of solid acidity.

  20. Heavy-Duty Emissions Control: Plasma-Facilitated vs Reformer-Assisted Lean NOx Catalysis

    SciTech Connect

    Aardahl, C; Rozmiarek, R; Rappe, K; Mendoza, D Park, P

    2003-08-24

    Progress has been made in the control of combustion processes to limit the formation of environmentally harmful species, but lean burn vehicles, such as those powered by diesel engines used for the majority of commercial trucking and off-road applications, remain a major source of nitrogen oxides (NOx) and particulate matter (PM) emissions. Tighter control of the combustion process coupled with exhaust gas recirculation has brought emissions in line with 2004 targets worldwide. Additional modifications to the engine control system, somewhat limited NOx control, and PM filters will likely allow the 2007 limits to be met for the on-highway regulations for heavy-duty engines in the United States. Concern arises when the NOx emission limit of 0.2 g/bhphr set for the year 2010 is considered.

  1. Effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions.

    PubMed

    Lv, Dong; Zhu, Tianle; Liu, Runwei; Lv, Qingzhi; Sun, Ye; Wang, Hongmei; Liu, Yu; Zhang, Fan

    2016-09-01

    The effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions were systematically investigated in a cement production line in Beijing. The results show that co-processing the sewage sludge was helpful to reduce NOx emission, which primarily depends on the NH3 amount released from the sewage sludge. Meanwhile, NOx and NH3 concentrations in the flue gas have a negative correlation, and the contribution of feeding the sewage sludge to NOx removal decreased with the increase of injection amount of ammonia water in the SNCR system. Therefore, it is suggested that the injection amount of ammonia water in SNCR system may reduce to cut down the operating costs during co-processing the sewage sludge in cement kiln. In addition, the emission of total PAHs seems to increase with the increased amount of the sewage sludge feeding to the cement kiln. However, the distributions of PAHs were barely changed, and lower molecular weight PAHs were mainly distributed in gaseous phase, accounted for the major portion of PAHs when co-processing sewage sludge in cement kiln.

  2. Effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions.

    PubMed

    Lv, Dong; Zhu, Tianle; Liu, Runwei; Lv, Qingzhi; Sun, Ye; Wang, Hongmei; Liu, Yu; Zhang, Fan

    2016-09-01

    The effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions were systematically investigated in a cement production line in Beijing. The results show that co-processing the sewage sludge was helpful to reduce NOx emission, which primarily depends on the NH3 amount released from the sewage sludge. Meanwhile, NOx and NH3 concentrations in the flue gas have a negative correlation, and the contribution of feeding the sewage sludge to NOx removal decreased with the increase of injection amount of ammonia water in the SNCR system. Therefore, it is suggested that the injection amount of ammonia water in SNCR system may reduce to cut down the operating costs during co-processing the sewage sludge in cement kiln. In addition, the emission of total PAHs seems to increase with the increased amount of the sewage sludge feeding to the cement kiln. However, the distributions of PAHs were barely changed, and lower molecular weight PAHs were mainly distributed in gaseous phase, accounted for the major portion of PAHs when co-processing sewage sludge in cement kiln. PMID:27343866

  3. Nuclear Nox4 Role in Stemness Power of Human Amniotic Fluid Stem Cells

    PubMed Central

    Maraldi, Tullia; Guida, Marianna; Zavatti, Manuela; Resca, Elisa; Bertoni, Laura; La Sala, Giovanni B.; De Pol, Anto

    2015-01-01

    Human amniotic fluid stem cells (AFSC) are an attractive source for cell therapy due to their multilineage differentiation potential and accessibility advantages. However the clinical application of human stem cells largely depends on their capacity to expand in vitro, since there is an extensive donor-to-donor heterogeneity. Reactive oxygen species (ROS) and cellular oxidative stress are involved in many physiological and pathophysiological processes of stem cells, including pluripotency, proliferation, differentiation, and stress resistance. The mode of action of ROS is also dependent on the localization of their target molecules. Thus, the modifications induced by ROS can be separated depending on the cellular compartments they affect. NAD(P)H oxidase family, particularly Nox4, has been known to produce ROS in the nucleus. In the present study we show that Nox4 nuclear expression (nNox4) depends on the donor and it correlates with the expression of transcription factors involved in stemness regulation, such as Oct4, SSEA-4, and Sox2. Moreover nNox4 is linked with the nuclear localization of redox sensitive transcription factors, as Nrf2 and NF-κB, and with the differentiation potential. Taken together, these results suggest that nNox4 regulation may have important effects in stem cell capability through modulation of transcription factors and DNA damage. PMID:26273418

  4. Turbulent Flame Speeds and NOx Kinetics of HHC Fuels with Contaminants and High Dilution Levels

    SciTech Connect

    Peterson, Eric; Krejci, Michael; Mathieu, Olivier; Vissotski, Andrew; Ravi, Sankat; Plichta, Drew; Sikes, Travis; Levacque, Anthony; Camou, Alejandro; Aul, Christopher

    2014-01-24

    This final report documents the technical results of the 3-year project entitled, “Turbulent Flame Speeds and NOx Kinetics of HHC Fuels with Contaminants and High Dilution Levels,” funded under the NETL of DOE. The research was conducted under six main tasks: 1) program management and planning; 2) turbulent flame speed measurements of syngas mixtures; 3) laminar flame speed measurements with diluents; 4) NOx mechanism validation experiments; 5) fundamental NOx kinetics; and 6) the effect of impurities on NOx kinetics. Experiments were performed using primary constant-volume vessels for laminar and turbulent flame speeds and shock tubes for ignition delay times and species concentrations. In addition to the existing shock- tube and flame speed facilities, a new capability in measuring turbulent flame speeds was developed under this grant. Other highlights include an improved NOx kinetics mechanism; a database on syngas blends for real fuel mixtures with and without impurities; an improved hydrogen sulfide mechanism; an improved ammonia kintics mechanism; laminar flame speed data at high pressures with water addition; and the development of an inexpensive absorption spectroscopy diagnostic for shock-tube measurements of OH time histories. The Project Results for this work can be divided into 13 major sections, which form the basis of this report. These 13 topics are divided into the five areas: 1) laminar flame speeds; 2) Nitrogen Oxide and Ammonia chemical kinetics; 3) syngas impurities chemical kinetics; 4) turbulent flame speeds; and 5) OH absorption measurements for chemical kinetics.

  5. The ROS-generating oxidase Nox1 is required for epithelial restitution following colitis.

    PubMed

    Kato, Masayoshi; Marumo, Masaya; Nakayama, Jun; Matsumoto, Misaki; Yabe-Nishimura, Chihiro; Kamata, Tohru

    2016-07-29

    Accumulating evidence suggests that reactive oxygen species (ROS) generated by endogenous metabolic enzymes are involved in a variety of intracellular mechanisms. In particular, superoxide-generating NADPH oxidase (Nox) 1 is highly expressed in the colon and has been implicated in physiological and pathophysiological states of colon tissues. However, its role in tissue repair following colitis has not been fully elucidated. Our study using experimental colitis in mice showed that repair of the mucosal layer did not occur in Nox1-deficient mice following dextran sulfate sodium-induced colitis. This was accompanied by inhibition of proliferation, cell survival, migration, and terminal differentiation (generation of goblet cells) of crypt progenitor cells, as determined by histochemical analyses. Furthermore, Nox1 expression as well as ROS production in the colon crypt was increased during the repair process, and Nox1 deficiency suppressed these events. The results suggest that Nox1 promotes colon mucosal wound repair by sustaining the bioactivity of crypt progenitor cells and plays a crucial role in the epithelial restitution in the case of damage associated with colitis. PMID:26876598

  6. The ROS-generating oxidase Nox1 is required for epithelial restitution following colitis

    PubMed Central

    Kato, Masayoshi; Marumo, Masaya; Nakayama, Jun; Matsumoto, Misaki; Yabe-Nishimura, Chihiro; Kamata, Tohru

    2016-01-01

    Accumulating evidence suggests that reactive oxygen species (ROS) generated by endogenous metabolic enzymes are involved in a variety of intracellular mechanisms. In particular, superoxide-generating NADPH oxidase (Nox) 1 is highly expressed in the colon and has been implicated in physiological and pathophysiological states of colon tissues. However, its role in tissue repair following colitis has not been fully elucidated. Our study using experimental colitis in mice showed that repair of the mucosal layer did not occur in Nox1-deficient mice following dextran sulfate sodium-induced colitis. This was accompanied by inhibition of proliferation, cell survival, migration, and terminal differentiation (generation of goblet cells) of crypt progenitor cells, as determined by histochemical analyses. Furthermore, Nox1 expression as well as ROS production in the colon crypt was increased during the repair process, and Nox1 deficiency suppressed these events. The results suggest that Nox1 promotes colon mucosal wound repair by sustaining the bioactivity of crypt progenitor cells and plays a crucial role in the epithelial restitution in the case of damage associated with colitis. PMID:26876598

  7. In2O3/Al2O3 Catalysts for NOx Reduction in Lean Condition

    SciTech Connect

    Park, Paul W.; Ragle, Christie; Boyer, Carrie S.; Balmer, M Lou; Engelhard, Mark H. ); McCready, David E. )

    2002-01-01

    The lean NOx performance and catalytic properties of In2O3/Al2O3 catalysts were investigated. High lean NOx activity was observed when propene was used as a reductant in the presence of 9% O2 and 7% H2O at a space velocity of 30,000h-1. The optimum lean NOx activity of In2O3/Al2O3 catalysts was observed at a loading of 2.5 wt.% indium on -Al2O3 which was prepared by a sol-gel technique (230 m2/g). When propane was used as a reductant, the In2O3/Al2O3 catalyst did not promote NOx reduction compared to the alumina substrate. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and temperature programmed reduction (TPR) have been used to characterize a series of In2O3/Al2O3 catalysts to better understand the surface structure of indium oxide species on the alumina support. The XRD data indicated that crystalline In2O3 was present at In2O3 loadings > 5wt.% and the quantity of the crystalline phase increased as a function of indium loading. XPS results suggested that indium oxide existed as a well-dispersed phase up to 10wt.% indium. The well dispersed or reducible indium oxide species below 400 C in TPR experiments were assigned as the sites which activate propene to oxygenated hydrocarbons such as acetaldehyde and acrolein. Alumina sites readily utilize the oxygenated hydrocarbons to reduce NOx. Dual-function mechanism was proposed to explain NOx reduction over In2O3/Al2O3 catalysts.

  8. System and method for diagnosing EGR performance using NOx sensor

    DOEpatents

    Mazur, Christopher John

    2003-12-23

    A method and system for diagnosing a condition of an EGR valve used in an engine system. The EGR valve controls the portion exhaust gases produced by such engine system and fed back to an intake of such engine system. The engine system includes a NOx sensor for measuring NOx in such exhaust. The method includes: determining a time rate of change in NOx measured by the NOx sensor; comparing the determined time rate of change in the measured NOx with a predetermined expected time rate of change in measured NOx; and determining the condition of the EGR valve as a function of such comparison. The method also includes: determining from NOx measured by the NOx sensor and engine operating conditions indications of instances when samples of such measured NOx are greater than an expected maximum NOx level for such engine condition and less than an expected minimum NOx level for such engine condition; and determining the condition of the EGR valve as a function of a statistical analysis of such indications. The method includes determining whether the NOx sensor is faulty and wherein the EGR condition determining includes determining whether the NOx sensor is faulty.

  9. Enhanced Combustion Low NOx Pulverized Coal Burner

    SciTech Connect

    David Towle; Richard Donais; Todd Hellewell; Robert Lewis; Robert Schrecengost

    2007-06-30

    For more than two decades, Alstom Power Inc. (Alstom) has developed a range of low cost, infurnace technologies for NOx emissions control for the domestic U.S. pulverized coal fired boiler market. This includes Alstom's internally developed TFS 2000{trademark} firing system, and various enhancements to it developed in concert with the U.S. Department of Energy. As of the date of this report, more than 270 units representing approximately 80,000 MWe of domestic coal fired capacity have been retrofit with Alstom low NOx technology. Best of class emissions range from 0.18 lb/MMBtu for bituminous coal to 0.10 lb/MMBtu for subbituminous coal, with typical levels at 0.24 lb/MMBtu and 0.13 lb/MMBtu, respectively. Despite these gains, NOx emissions limits in the U.S. continue to ratchet down for new and existing boiler equipment. On March 10, 2005, the Environmental Protection Agency (EPA) announced the Clean Air Interstate Rule (CAIR). CAIR requires 25 Eastern states to reduce NOx emissions from the power generation sector by 1.7 million tons in 2009 and 2.0 million tons by 2015. Low cost solutions to meet such regulations, and in particular those that can avoid the need for a costly selective catalytic reduction system (SCR), provide a strong incentive to continue to improve low NOx firing system technology to meet current and anticipated NOx control regulations. The overall objective of the work is to develop an enhanced combustion, low NOx pulverized coal burner, which, when integrated with Alstom's state-of-the-art, globally air staged low NOx firing systems will provide a means to achieve: Less than 0.15 lb/MMBtu NOx emissions when firing a high volatile Eastern or Western bituminous coal, Less than 0.10 lb/MMBtu NOx emissions when firing a subbituminous coal, NOx reduction costs at least 25% lower than the costs of an SCR, Validation of the NOx control technology developed through large (15 MWt) pilot scale demonstration, and Documentation required for economic

  10. NOx production and rainout from Chicxulub impact ejecta reentry

    NASA Astrophysics Data System (ADS)

    Parkos, Devon; Alexeenko, Alina; Kulakhmetov, Marat; Johnson, Brandon C.; Melosh, H. Jay

    2015-12-01

    The Chicxulub impact 66.0 Ma ago initiated the second biggest extinction in the Phanerozoic Eon. The cause of the concurrent oceanic nitrogen isotopic anomaly, however, remains elusive. The Chicxulub impactor struck the Yucatán peninsula, ejecting 2 × 1015 kg of molten and vaporized rock that reentered globally as approximately 1023 microscopic spherules. Here we report that modern techniques indicate that this ejecta generates 1.5 × 1014 moles of NOx, which is enough to cause the observed nitrogen enrichment of the basal layer. Additionally, reentry-based NO production would explain the anomalously heavy isotopic composition of the observed nitrogen. We include N, O, N2, O2, and NO species in simulations of nonequilibrium chemically reacting flow around a reentering spherule. We then determine the net production of NO from all the spherules and use turbulence models to determine how quickly this yield diffuses through the atmosphere. Upon reaching the stratosphere and troposphere, cloud moisture absorbs the NOx and forms nitric acid. We model this process and determine the acidity of the resulting precipitation, which peaks about 1 year after the impact. The precipitation ultimately reaches the upper ocean, where we assume that the well-mixed surface layer is 100 m deep. We then model the naturally occurring carbonate/bicarbonate buffer and determine the net pH. We find that insufficient NOx reaches the ocean to directly cause the observed end-Cretaceous oceanic extinction via acidification and buffer removal. However, the resulting nitrates are sufficient to explain the concurrent nitrogen isotopic anomaly and facilitate an end-Cretaceous algae bloom.

  11. Overall evaluation of combustion and NO(x) emissions for a down-fired 600 MW(e) supercritical boiler with multiple injection and multiple staging.

    PubMed

    Kuang, Min; Li, Zhengqi; Liu, Chunlong; Zhu, Qunyi

    2013-05-01

    To achieve significant reductions in NOx emissions and to eliminate strongly asymmetric combustion found in down-fired boilers, a deep-air-staging combustion technology was trialed in a down-fired 600 MWe supercritical utility boiler. By performing industrial-sized measurements taken of gas temperatures and species concentrations in the near wing-wall region, carbon in fly ash and NOx emissions at various settings, effects of overfire air (OFA) and staged-air damper openings on combustion characteristics, and NOx emissions within the furnace were experimentally determined. With increasing the OFA damper opening, both fluctuations in NOx emissions and carbon in fly ash were initially slightly over OFA damper openings of 0-40% but then lengthened dramatically in openings of 40-70% (i.e., NOx emissions reduced sharply accompanied by an apparent increase in carbon in fly ash). Decreasing the staged-air declination angle clearly increased the combustible loss but slightly influenced NOx emissions. In comparison with OFA, the staged-air influence on combustion and NOx emissions was clearly weaker. Only at a high OFA damper opening of 50%, the staged-air effect was relatively clear, i.e., enlarging the staged-air damper opening decreased carbon in fly ash and slightly raised NOx emissions. By sharply opening the OFA damper to deepen the air-staging conditions, although NOx emissions could finally reduce to 503 mg/m(3) at 6% O2 (i.e., an ultralow NOx level for down-fired furnaces), carbon in fly ash jumped sharply to 15.10%. For economical and environment-friendly boiler operations, an optimal damper opening combination (i.e., 60%, 50%, and 50% for secondary air, staged-air, and OFA damper openings, respectively) was recommended for the furnace, at which carbon in fly ash and NOx emissions attained levels of about 10% and 850 mg/m(3) at 6% O2, respectively.

  12. 40 CFR 96.53 - Recordation of NOX allowance allocations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE... allocated to an allocation set-aside. (c) Serial numbers for allocated NO X allowances. When allocating...

  13. 40 CFR 96.53 - Recordation of NOX allowance allocations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS FOR STATE... allocated to an allocation set-aside. (c) Serial numbers for allocated NO X allowances. When allocating...

  14. Control of NOx Emissions from Stationary Combustion Sources

    EPA Science Inventory

    In general, NOx control technologies are categorized as being either primary control technologies or secondary control technologies. Primary control technologies reduce the formation of NOx in the primary combustion zone. In contrast, secondary control technologies destroy the NO...

  15. Improved low NOx firing systems for pulverized coal combustion

    SciTech Connect

    McCarthy, K.; Laux, S.; Grusha, J.; Rosin, T.; Hausman, G.L.

    1999-07-01

    More stringent emission limits or the addition of post combustion NOx control create the need for improvements of NOx emissions from pulverized coal boilers. Many boilers retrofitted with Low NOx technology during Phase 1 and Phase 2 of the CAAA fail or marginally meet their requirements. Technical solutions range from addition of overfire air and state-of-the-art low NOx burners to low cost additions of combustion enhancements. Regardless of the combustion NOx control method used, stoichiometries local to the burners must be maintained at the designed values at all times to provide high NOx performance at low efficiency loss due to unburned fuel. This paper describes Foster Wheeler's approach to NOx emission improvements for existing low NOx firing systems. The technology to measure air and coal flow individually for each burner and to control the parameters for optimum combustion are presented and discussed. Field experience shows the installation and advantages of the technology.

  16. Carbon Honeycomb High Capacity Storage for Gaseous and Liquid Species

    NASA Astrophysics Data System (ADS)

    Krainyukova, Nina V.; Zubarev, Evgeniy N.

    2016-02-01

    We report an exceptionally stable honeycomb carbon allotrope obtained by deposition of vacuum-sublimated graphite. The allotrope structures are derived from our low temperature electron diffraction and electron microscopy data. These structures can be both periodic and random and are built exclusively from s p2 -bonded carbon atoms, and may be considered as three-dimensional graphene. They demonstrate high levels of physical absorption of various gases unattainable in other carbon forms such as fullerites or nanotubes. These honeycomb structures can be used not only for storage of various gases and liquids but also as a matrix for new composites.

  17. Gaseous and particulate composition of fresh and aged emissions of diesel, RME and CNG buses using Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Psichoudaki, Magda; Le Breton, Michael; Hallquist, Mattias; Watne, Ågot; Hallquist, Asa

    2016-04-01

    . A Time-of-Flight Chemical Ionization Mass Spectrometer (ToF-CIMS) was employed to monitor the concentration of different organic species present in the fresh and aged emissions. This instrument is capable of identifying the molecular formulas of species in the gas phase. The FIGAERO inlet, also enabled the characterisation of the particle phase, as particles were simultaneously collected on a filter, from which they could then be thermally desorbed and detected. Acetate (negative) ionization was utilised to allow high sensitivity measurements of organic acids, aldehydes, ketones, diols and halogenated species. The H2O, O3 and NOx concentrations inside the PAM flow reactor were monitored, and an organic tracer for OH exposure was also continuously measured. The concentrations of dominant species in both fresh and aged gaseous and particulate bus emissions from the different fuel types will be presented as well as their emission factors, calculated from concurrent CO2 measurements.

  18. 40 CFR 97.41 - Timing requirements for NOX allowance allocations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Timing requirements for NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Allocations § 97.41 Timing requirements for NOX allowance allocations. (a) The NOX allowance...

  19. 40 CFR 97.41 - Timing requirements for NOX allowance allocations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Timing requirements for NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Allocations § 97.41 Timing requirements for NOX allowance allocations. (a) The NOX allowance...

  20. 40 CFR 97.41 - Timing requirements for NOX allowance allocations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Timing requirements for NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Allocations § 97.41 Timing requirements for NOX allowance allocations. (a) The NOX allowance...

  1. 40 CFR 97.41 - Timing requirements for NOX allowance allocations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Timing requirements for NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Allocations § 97.41 Timing requirements for NOX allowance allocations. (a) The NOX allowance...

  2. Gaseous insulators for high voltage electrical equipment

    DOEpatents

    Christophorou, Loucas G.; James, David R.; Pace, Marshall O.; Pai, Robert Y.

    1979-01-01

    Gaseous insulators comprise compounds having high attachment cross sections for electrons having energies in the 0-1.3 electron volt range. Multi-component gaseous insulators comprise compounds and mixtures having overall high electron attachment cross sections in the 0-1.3 electron volt range and moderating gases having high cross sections for inelastic interactions with electrons of energies 1-4 electron volts. Suitable electron attachment components include hexafluorobutyne, perfluorobutene-2, perfluorocyclobutane, perfluorodimethylcyclobutane, perfluorocyclohexene, perfluoromethylcyclohexane, hexafluorobutadiene, perfluoroheptene-1 and hexafluoroazomethane. Suitable moderating gases include N.sub.2, CO, CO.sub.2 and H.sub.2. The gaseous insulating mixture can also contain SF.sub.6, perfluoropropane and perfluorobenzene.

  3. Gaseous insulators for high voltage electrical equipment

    DOEpatents

    Christophorou, Loucas G.; James, David R.; Pace, Marshall O.; Pai, Robert Y.

    1981-01-01

    Gaseous insulators comprise compounds having high attachment cross sections for electrons having energies in the 0-1.3 electron volt range. Multi-component gaseous insulators comprise compounds and mixtures having overall high electron attachment cross sections in the 0-1.3 electron volt range and moderating gases having high cross sections for inelastic interactions with electrons of energies 1-4 electron volts. Suitable electron attachment components include hexafluorobutyne, perfluorobutene-2, perfluorocyclobutane, perfluorodimethylcyclobutane, perfluorocyclohexene, perfluoromethylcyclohexane, hexafluorobutadiene, perfluoroheptene-1 and hexafluoroazomethane. Suitable moderating gases include N.sub.2, CO, CO.sub.2 and H.sub.2. The gaseous insulating mixture can also contain SF.sub.6, perfluoropropane and perfluorobenzene.

  4. Gaseous fuel reactors for power systems

    NASA Technical Reports Server (NTRS)

    Kendall, J. S.; Rodgers, R. J.

    1977-01-01

    Gaseous-fuel nuclear reactors have significant advantages as energy sources for closed-cycle power systems. The advantages arise from the removal of temperature limits associated with conventional reactor fuel elements, the wide variety of methods of extracting energy from fissioning gases, and inherent low fissile and fission product in-core inventory due to continuous fuel reprocessing. Example power cycles and their general performance characteristics are discussed. Efficiencies of gaseous fuel reactor systems are shown to be high with resulting minimal environmental effects. A technical overview of the NASA-funded research program in gaseous fuel reactors is described and results of recent tests of uranium hexafluoride (UF6)-fueled critical assemblies are presented.

  5. GASEOUS ELEMENTAL MERCURY IN THE MARINE BOUNDARY LAYER: EVIDENCE FOR RAPID REMOVAL IN ANTHROPOGENIC POLLUTION

    EPA Science Inventory

    In this study, gas-phase elemental mercury (Hg0) and related species (including inorganic reactive gaseous mercury (RGM) and particulate mercury (PHg)) were measured at Cheeka Peak Observatory (CPO), Washington State, in the marine boundary layer (MBL) during 2001-2002. Air of...

  6. Direct Measurements of NOx Produced by Lightning

    NASA Astrophysics Data System (ADS)

    Rahman, M.; Cooray, V.; Rakov, V. A.; Uman, M. A.; Liyanage, P.; Decarlo, B. A.; Jerauld, J.; Olsen, R. C.

    2006-12-01

    We present the first direct measurements of NOx generated by lightning. In July 2005, three negative lightning flashes were triggered using the rocket-and-wire technique at the International Center for Lightning Research and Testing (ICLRT) at Camp Blanding, Florida. The NOx produced by these three rocket- triggered flashes was measured, using the chemiluminescence method, by isolating a 3-cm long section of the lightning channel within a discharge chamber whose volume was 0.77 m3. We measured NOx individually for the first flash, which was triggered on July 15, and cumulatively for the other two flashes, which were triggered within about eleven minutes of each other on July 31. The July 15 flash contained only an initial- stage current and no return strokes. Each of the July 31 flashes contained an initial-stage current and either one or two return strokes. The initial-stage current in each case had a duration in the range from 260 to 360 ms, and one return stroke in each July 31 flash was followed by a continuing current whose duration was greater than 40 ms. The NOx production by the July 15 flash without return strokes (total charge transfer of 77 C) was 2.0×10^{22} molecules per meter of lightning channel, and that by the two July 31 flashes with return strokes (total charge transfer of 108 C) was 2.4×10^{22} molecules per meter. The NOx production per unit charge for these two measurements was similar: 2.6×1020 and 2.2×1020 molecules per meter per coulomb. It appears that the NOx production is primarily from long-duration, steady currents, as opposed to microsecond-scale impulsive return stroke currents. This observation implies that cloud discharges, which transfer, on average, larger charges than ground discharges, but do not contain return strokes (although they do contain typically shorter and presumably smaller amplitude microsecond-scale pulses) may be as effective as (or more effective than) cloud-to-ground discharges in producing NOx in the

  7. The use of vacuum ultraviolet irradiation to oxidize SO₂ and NOx for simultaneous desulfurization and denitrification.

    PubMed

    Ye, Junhui; Shang, Jing; Li, Qian; Xu, Weiwei; Liu, Jia; Feng, Xiang; Zhu, Tong

    2014-04-30

    A simple and efficient method for simultaneous desulfurization and denitrification via vacuum ultraviolet (VUV) irradiation and with no additional chemicals is presented. The simultaneous removal of 90% SO2 and 96% NOx (NO+NO2) was achieved from the simulated flue gas under the irradiation from a low-pressure mercury lamp with main wavelengths of 185 and 254 nm, respectively. The composition, flow rate, and temperature of the simulated flue gas, as well as the VUV light intensity, were evaluated as the factors impacting on the efficiency of SO2 and NOx removal. The OH, HO2, O, and O3 produced from the photolysis of H2O and O2 were concluded as the major reactive oxygen species that oxidized SO2 and NOx. The additional OH and HO2 generated through the reactions of NO+HO2 and SO2+OH/HO2 improved treatment efficiency, while the oxidation products of NOx, e.g., NO2, HNO2, HNO3, and HNO4, consumed massive reactive oxygen species (such as O, OH, and HO2) and thereby reducing the removal efficiencies. The main reaction products were characterized as H2SO4 and HNO3 by ion chromatography, which could be used as chemical or fertilizer raw materials. PMID:24632363

  8. 40 CFR 97.24 - NOX Budget permit revisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false NOX Budget permit revisions. 97.24 Section 97.24 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.24...

  9. 40 CFR 97.23 - NOX Budget permit contents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Budget permit contents. 97.23 Section 97.23 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.23...

  10. 40 CFR 89.317 - NOX converter check.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., the chemiluminescent oxides of nitrogen analyzer shall be checked for NO2 to NO converter efficiency... concentration of residual NO. (i) Switch the oxides of nitrogen analyzer to the NOX mode and measure total NOX... of the NOX generator to the sample inlet of the oxides of nitrogen analyzer which has been......

  11. 40 CFR 90.319 - NOX converter check.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Provisions § 90.319 NOX converter check. (a) The efficiency of the converter used for the conversion of NO2... percent of the NO concentration). The NOX analyzer must be in the NO mode so that the span gas does not... the highest range which will give the reduction. (6) Switch the NO analyzer to the NOX mode...

  12. 40 CFR 90.319 - NOX converter check.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Provisions § 90.319 NOX converter check. (a) The efficiency of the converter used for the conversion of NO2... percent of the NO concentration). The NOX analyzer must be in the NO mode so that the span gas does not... the highest range which will give the reduction. (6) Switch the NO analyzer to the NOX mode...

  13. 40 CFR 89.317 - NOX converter check.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., the chemiluminescent oxides of nitrogen analyzer shall be checked for NO2 to NO converter efficiency... concentration of residual NO. (i) Switch the oxides of nitrogen analyzer to the NOX mode and measure total NOX... of the NOX generator to the sample inlet of the oxides of nitrogen analyzer which has been......

  14. 40 CFR 90.319 - NOX converter check.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Provisions § 90.319 NOX converter check. (a) The efficiency of the converter used for the conversion of NO2... percent of the NO concentration). The NOX analyzer must be in the NO mode so that the span gas does not... the highest range which will give the reduction. (6) Switch the NO analyzer to the NOX mode...

  15. 40 CFR 97.42 - NOX allowance allocations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Allocations § 97.42 NOX allowance allocations. (a)(1) The heat input (in mmBtu) used for calculating NOX...'s heat input for the control periods in 1995 through 1998; or (B) For a unit under § 97.4(a)(2), the... control periods in 1996 through 1998, the average of the two highest amounts of the unit's heat input...

  16. 40 CFR 96.23 - NOX Budget permit contents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false NOX Budget permit contents. 96.23 Section 96.23 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Permits § 96.23 NOX Budget permit contents. (a) Each NOX Budget permit (including any draft or...

  17. Gaseous hydrogen embrittlement of high strength steels

    NASA Technical Reports Server (NTRS)

    Gangloff, R. P.; Wei, R. P.

    1977-01-01

    The effects of temperature, hydrogen pressure, stress intensity, and yield strength on the kinetics of gaseous hydrogen assisted crack propagation in 18Ni maraging steels were investigated experimentally. It was found that crack growth rate as a function of stress intensity was characterized by an apparent threshold for crack growth, a stage where the growth rate increased sharply, and a stage where the growth rate was unchanged over a significant range of stress intensity. Cracking proceeded on load application with little or no detectable incubation period. Gaseous hydrogen embrittlement susceptibility increased with increasing yield strength.

  18. The depletion of interstellar gaseous iron

    NASA Technical Reports Server (NTRS)

    Savage, B. D.; Bohlin, R. C.

    1979-01-01

    The Copernicus UV telescope was used to measure equivalent widths of interstellar Fe II resonance lines toward 55 early-type stars; the measurements permit the determination of Fe II column densities. The depletion of interstellar gaseous iron was obtained by combining these measurements with the results from a previous atomic and molecular hydrogen survey program; the derived depletions refer mostly to matter in H I regions. As an example, the nearly normal gaseous iron abundance in the distant high-latitude intermediate-velocity cloud toward HD 93521 is consistent with the idea that these clouds are produced by galactic supernova explosions.

  19. Interactions of gaseous-pollutant and acid-rain effects

    SciTech Connect

    Shriner, D.S.

    1983-01-01

    This research addresses the significance of individual and combined effects of gaseous pollutants and acid rain on plant growth and development. It is specifically structured to determine the importance of pollutant interactions at concentrations, combinations and exposure frequencies typical of the eastern regional environment. Laboratory, greenhouse, and field studies are designed to establish pollutant-concentration thresholds for damage from SO/sub 2/, O/sub 3/, NO/sub x/, and acid rain. Research to date has determined visible-injury thresholds and growth-and-yield thresholds for a variety of cultivars of bean, wheat, radish, tomato, and loblolly pine. The thresholds vary within cultivars of a species and between species.

  20. Predicting gaseous emissions from small-scale combustion of agricultural biomass fuels.

    PubMed

    Fournel, S; Marcos, B; Godbout, S; Heitz, M

    2015-03-01

    A prediction model of gaseous emissions (CO, CO2, NOx, SO2 and HCl) from small-scale combustion of agricultural biomass fuels was developed in order to rapidly assess their potential to be burned in accordance to current environmental threshold values. The model was established based on calculation of thermodynamic equilibrium of reactive multicomponent systems using Gibbs free energy minimization. Since this method has been widely used to estimate the composition of the syngas from wood gasification, the model was first validated by comparing its prediction results with those of similar models from the literature. The model was then used to evaluate the main gas emissions from the combustion of four dedicated energy crops (short-rotation willow, reed canary grass, switchgrass and miscanthus) previously burned in a 29-kW boiler. The prediction values revealed good agreement with the experimental results. The model was particularly effective in estimating the influence of harvest season on SO2 emissions. PMID:25543541

  1. Predicting gaseous emissions from small-scale combustion of agricultural biomass fuels.

    PubMed

    Fournel, S; Marcos, B; Godbout, S; Heitz, M

    2015-03-01

    A prediction model of gaseous emissions (CO, CO2, NOx, SO2 and HCl) from small-scale combustion of agricultural biomass fuels was developed in order to rapidly assess their potential to be burned in accordance to current environmental threshold values. The model was established based on calculation of thermodynamic equilibrium of reactive multicomponent systems using Gibbs free energy minimization. Since this method has been widely used to estimate the composition of the syngas from wood gasification, the model was first validated by comparing its prediction results with those of similar models from the literature. The model was then used to evaluate the main gas emissions from the combustion of four dedicated energy crops (short-rotation willow, reed canary grass, switchgrass and miscanthus) previously burned in a 29-kW boiler. The prediction values revealed good agreement with the experimental results. The model was particularly effective in estimating the influence of harvest season on SO2 emissions.

  2. Reduction of gaseous pollutant emissions from gas turbine combustors using hydrogen-enriched jet fuel

    NASA Technical Reports Server (NTRS)

    Clayton, R. M.

    1976-01-01

    Recent progress in an evaluation of the applicability of the hydrogen enrichment concept to achieve ultralow gaseous pollutant emission from gas turbine combustion systems is described. The target emission indexes for the program are 1.0 for oxides of nitrogen and carbon monoxide, and 0.5 for unburned hydrocarbons. The basic concept utilizes premixed molecular hydrogen, conventional jet fuel, and air to depress the lean flammability limit of the mixed fuel. This is shown to permit very lean combustion with its low NOx production while simulataneously providing an increased flame stability margin with which to maintain low CO and HC emission. Experimental emission characteristics and selected analytical results are presented for a cylindrical research combustor designed for operation with inlet-air state conditions typical for a 30:1 compression ratio, high bypass ratio, turbofan commercial engine.

  3. Molecular characterization of the NADPH oxidase complex in the ergot fungus Claviceps purpurea: CpNox2 and CpPls1 are important for a balanced host-pathogen interaction.

    PubMed

    Schürmann, Janine; Buttermann, Dagmar; Herrmann, Andrea; Giesbert, Sabine; Tudzynski, Paul

    2013-10-01

    Reactive oxygen species producing NADPH oxidase (Nox) complexes are involved in defense reactions in animals and plants while they trigger infection-related processes in pathogenic fungi. Knowledge about the composition and localization of these complexes in fungi is limited; potential components identified thus far include two to three catalytical subunits, a regulatory subunit (NoxR), the GTPase Rac, the scaffold protein Bem1, and a tetraspanin-like membrane protein (Pls1). We showed that, in the biotrophic grass-pathogen Claviceps purpurea, the catalytical subunit CpNox1 is important for infection. Here, we present identification of major Nox complex partners and a functional analysis of CpNox2 and the tetraspanin CpPls1. We show that, as in other fungi, Nox complexes are important for formation of sclerotia; CpRac is, indeed, a complex partner because it interacts with CpNoxR, and CpNox1/2 and CpPls1 are associated with the endoplasmatic reticulum. However, unlike in all other fungi, Δcppls1 is more similar to Δcpnox1 than to Δcpnox2, and CpNox2 is not essential for infection. In contrast, Δcpnox2 shows even more pronounced disease symptoms, indicating that Cpnox2 controls the infection process and moderates damage to the host. These data confirm that fungal Nox complexes have acquired specific functions dependent of the lifestyle of the pathogen. PMID:23777432

  4. Characterization of NOx, SO2, ethene, and propene from industrial emission sources in Houston, Texas

    NASA Astrophysics Data System (ADS)

    Washenfelder, R. A.; Trainer, M.; Frost, G. J.; Ryerson, T. B.; Atlas, E. L.; de Gouw, J. A.; Flocke, F. M.; Fried, A.; Holloway, J. S.; Parrish, D. D.; Peischl, J.; Richter, D.; Schauffler, S. M.; Walega, J. G.; Warneke, C.; Weibring, P.; Zheng, W.

    2010-08-01

    The Houston-Galveston-Brazoria urban area contains industrial petrochemical sources that emit volatile organic compounds and nitrogen oxides, resulting in rapid and efficient ozone production downwind. During September to October 2006, the NOAA WP-3D aircraft conducted research flights as part of the second Texas Air Quality Study (TexAQS II). We use measurements of NOx, SO2, and speciated hydrocarbons from industrial sources in Houston to derive source emission ratios and compare these to emission inventories and the first Texas Air Quality Study (TexAQS) in 2000. Between 2000 and 2006, NOx/CO2 emission ratios changed by an average of -29% ± 20%, while a significant trend in SO2/CO2 emission ratios was not observed. We find that high hydrocarbon emissions are routine for the isolated petrochemical facilities. Ethene (C2H4) and propene (C3H6) are the major contributors to ozone formation based on calculations of OH reactivity for organic species including C2-C10 alkanes, C2-C5 alkenes, ethyne, and C2-C5 aldehydes and ketones. Measured ratios of C2H4/NOx and C3H6/NOx exceed emission inventory values by factors of 1.4-20 and 1-24, respectively. We examine trends in C2H4/NOx and C3H6/NOx ratios between 2000 and 2006 for the isolated petrochemical sources and estimate a change of -30% ± 30%, with significant day-to-day and within-plume variability. Median ambient mixing ratios of ethene and propene in Houston show decreases of -52% and -48%, respectively, between 2000 and 2006. The formaldehyde, acetaldehyde, and peroxyacetyl nitrate products produced by alkene oxidation are observed downwind, and their time evolution is consistent with the rapid photochemistry that also produces ozone.

  5. Apocynin and Nox2 regulate NF-κB by modifying thioredoxin-1 redox-state

    PubMed Central

    Trevelin, Silvia Cellone; dos Santos, Célio Xavier; Ferreira, Raphael Gomes; de Sá Lima, Larissa; Silva, Rangel Leal; Scavone, Cristoforo; Curi, Rui; Alves-Filho, José Carlos; Cunha, Thiago Mattar; Roxo-Júnior, Pérsio; Cervi, Maria-Célia; Laurindo, Francisco Rafael Martins; Hothersall, John Stephen; Cobb, Andrew M.; Zhang, Min; Ivetic, Aleksandar; Shah, Ajay M.; Lopes, Lucia Rossetti; Cunha, Fernando Queiroz

    2016-01-01

    The reactive-oxygen-species-(ROS)-generating-enzyme Nox2 is essential for leukocyte anti-microbial activity. However its role in cellular redox homeostasis and, consequently, in modulating intracellular signaling pathways remains unclear. Herein, we show Nox2 activation favors thioredoxin-1 (TRX-1)/p40phox interaction, which leads to exclusion of TRX-1 from the nucleus. In contrast, the genetic deficiency of Nox2 or its pharmacological inhibition with apocynin (APO) results in reductive stress after lipopolysaccharide-(LPS)-cell stimulation, which causes nuclear accumulation of TRX-1 and enhanced transcription of inflammatory mediators through nuclear-factor-(NF)-κB. The NF-κB overactivation is prevented by TRX-1 oxidation using inhibitors of thioredoxin reductase-1 (TrxR-1). The Nox2/TRX-1/NF-κB intracellular signaling pathway is involved in the pathophysiology of chronic granulomatous disease (CGD) and sepsis. In fact, TrxR-1 inhibition prevents nuclear accumulation of TRX-1 and LPS-stimulated hyperproduction of tumor-necrosis-factor-(TNF)-α by monocytes and neutrophils purified from blood of CGD patients, who have deficient Nox2 activity. TrxR-1 inhibitors, either lanthanum chloride (LaCl3) or auranofin (AUR), also increase survival rates of mice undergoing cecal-ligation-and-puncture-(CLP). Therefore, our results identify a hitherto unrecognized Nox2-mediated intracellular signaling pathway that contributes to hyperinflammation in CGD and in septic patients. Additionally, we suggest that TrxR-1 inhibitors could be potential drugs to treat patients with sepsis, particularly in those with CGD. PMID:27698473

  6. NOX2 Inhibition Impairs Early Muscle Gene Expression Induced by a Single Exercise Bout.

    PubMed

    Henríquez-Olguín, Carlos; Díaz-Vegas, Alexis; Utreras-Mendoza, Yildy; Campos, Cristian; Arias-Calderón, Manuel; Llanos, Paola; Contreras-Ferrat, Ariel; Espinosa, Alejandra; Altamirano, Francisco; Jaimovich, Enrique; Valladares, Denisse M

    2016-01-01

    Reactive oxygen species (ROS) participate as signaling molecules in response to exercise in skeletal muscle. However, the source of ROS and the molecular mechanisms involved in these phenomena are still not completely understood. The aim of this work was to study the role of skeletal muscle NADPH oxidase isoform 2 (NOX2) in the molecular response to physical exercise in skeletal muscle. BALB/c mice, pre-treated with a NOX2 inhibitor, apocynin, (3 mg/kg) or vehicle for 3 days, were swim-exercised for 60 min. Phospho-p47(phox) levels were significantly upregulated by exercise in flexor digitorum brevis (FDB). Moreover, exercise significantly increased NOX2 complex assembly (p47(phox)-gp91(phox) interaction) demonstrated by both proximity ligation assay and co-immunoprecipitation. Exercise-induced NOX2 activation was completely inhibited by apocynin treatment. As expected, exercise increased the mRNA levels of manganese superoxide dismutase (MnSOD), glutathione peroxidase (GPx), citrate synthase (CS), mitochondrial transcription factor A (tfam) and interleukin-6 (IL-I6) in FDB muscles. Moreover, the apocynin treatment was associated to a reduced activation of p38 MAP kinase, ERK 1/2, and NF-κB signaling pathways after a single bout of exercise. Additionally, the increase in plasma IL-6 elicited by exercise was decreased in apocynin-treated mice compared with the exercised vehicle-group (p < 0.001). These results were corroborated using gp91-dstat in an in vitro exercise model. In conclusion, NOX2 inhibition by both apocynin and gp91dstat, alters the intracellular signaling to exercise and electrical stimuli in skeletal muscle, suggesting that NOX2 plays a critical role in molecular response to an acute exercise.

  7. NOX2 Inhibition Impairs Early Muscle Gene Expression Induced by a Single Exercise Bout

    PubMed Central

    Henríquez-Olguín, Carlos; Díaz-Vegas, Alexis; Utreras-Mendoza, Yildy; Campos, Cristian; Arias-Calderón, Manuel; Llanos, Paola; Contreras-Ferrat, Ariel; Espinosa, Alejandra; Altamirano, Francisco; Jaimovich, Enrique; Valladares, Denisse M.

    2016-01-01

    Reactive oxygen species (ROS) participate as signaling molecules in response to exercise in skeletal muscle. However, the source of ROS and the molecular mechanisms involved in these phenomena are still not completely understood. The aim of this work was to study the role of skeletal muscle NADPH oxidase isoform 2 (NOX2) in the molecular response to physical exercise in skeletal muscle. BALB/c mice, pre-treated with a NOX2 inhibitor, apocynin, (3 mg/kg) or vehicle for 3 days, were swim-exercised for 60 min. Phospho–p47phox levels were significantly upregulated by exercise in flexor digitorum brevis (FDB). Moreover, exercise significantly increased NOX2 complex assembly (p47phox–gp91phox interaction) demonstrated by both proximity ligation assay and co-immunoprecipitation. Exercise-induced NOX2 activation was completely inhibited by apocynin treatment. As expected, exercise increased the mRNA levels of manganese superoxide dismutase (MnSOD), glutathione peroxidase (GPx), citrate synthase (CS), mitochondrial transcription factor A (tfam) and interleukin-6 (IL-I6) in FDB muscles. Moreover, the apocynin treatment was associated to a reduced activation of p38 MAP kinase, ERK 1/2, and NF-κB signaling pathways after a single bout of exercise. Additionally, the increase in plasma IL-6 elicited by exercise was decreased in apocynin-treated mice compared with the exercised vehicle-group (p < 0.001). These results were corroborated using gp91-dstat in an in vitro exercise model. In conclusion, NOX2 inhibition by both apocynin and gp91dstat, alters the intracellular signaling to exercise and electrical stimuli in skeletal muscle, suggesting that NOX2 plays a critical role in molecular response to an acute exercise. PMID:27471471

  8. NOX2 Inhibition Impairs Early Muscle Gene Expression Induced by a Single Exercise Bout.

    PubMed

    Henríquez-Olguín, Carlos; Díaz-Vegas, Alexis; Utreras-Mendoza, Yildy; Campos, Cristian; Arias-Calderón, Manuel; Llanos, Paola; Contreras-Ferrat, Ariel; Espinosa, Alejandra; Altamirano, Francisco; Jaimovich, Enrique; Valladares, Denisse M

    2016-01-01

    Reactive oxygen species (ROS) participate as signaling molecules in response to exercise in skeletal muscle. However, the source of ROS and the molecular mechanisms involved in these phenomena are still not completely understood. The aim of this work was to study the role of skeletal muscle NADPH oxidase isoform 2 (NOX2) in the molecular response to physical exercise in skeletal muscle. BALB/c mice, pre-treated with a NOX2 inhibitor, apocynin, (3 mg/kg) or vehicle for 3 days, were swim-exercised for 60 min. Phospho-p47(phox) levels were significantly upregulated by exercise in flexor digitorum brevis (FDB). Moreover, exercise significantly increased NOX2 complex assembly (p47(phox)-gp91(phox) interaction) demonstrated by both proximity ligation assay and co-immunoprecipitation. Exercise-induced NOX2 activation was completely inhibited by apocynin treatment. As expected, exercise increased the mRNA levels of manganese superoxide dismutase (MnSOD), glutathione peroxidase (GPx), citrate synthase (CS), mitochondrial transcription factor A (tfam) and interleukin-6 (IL-I6) in FDB muscles. Moreover, the apocynin treatment was associated to a reduced activation of p38 MAP kinase, ERK 1/2, and NF-κB signaling pathways after a single bout of exercise. Additionally, the increase in plasma IL-6 elicited by exercise was decreased in apocynin-treated mice compared with the exercised vehicle-group (p < 0.001). These results were corroborated using gp91-dstat in an in vitro exercise model. In conclusion, NOX2 inhibition by both apocynin and gp91dstat, alters the intracellular signaling to exercise and electrical stimuli in skeletal muscle, suggesting that NOX2 plays a critical role in molecular response to an acute exercise. PMID:27471471

  9. Which NADPH Oxidase Isoform Is Relevant for Ischemic Stroke? The Case for Nox 2

    PubMed Central

    Kahles, Timo

    2013-01-01

    Abstract Significance and Recent Advances: Ischemic stroke is the leading cause of disability and third in mortality in industrialized nations. Immediate restoration of cerebral blood flow is crucial to salvage brain tissue, but only few patients are eligible for recanalization therapy. Thus, the need for alternative neuroprotective strategies is huge, and antioxidant interventions have long been studied in this context. Reactive oxygen species (ROS) physiologically serve as signaling molecules, but excessive amounts of ROS, as generated during ischemia/reperfusion (I/R), contribute to tissue injury. Critical Issues: Nevertheless and despite a strong rational of ROS being a pharmacological target, all antioxidant interventions failed to improve functional outcome in human clinical trials. Antioxidants may interfere with physiological functions of ROS or do not reach the crucial target structures of ROS-induced injury effectively. Future Directions: Thus, a potentially more promising approach is the inhibition of the source of disease-promoting ROS. Within recent years, NADPH oxidases (Nox) of the Nox family have been identified as mediators of neuronal pathology. As, however, several Nox homologs are expressed in neuronal tissue, and as many of the pharmacological inhibitors employed are rather unspecific, the concept of Nox as mediators of brain damage is far from being settled. In this review, we will discuss the contribution of Nox homologs to I/R injury at large as well as to neuronal damage in particular. We will illustrate that the current data provide evidence for Nox2 as the most important NADPH oxidase mediating cerebral injury. Antioxid. Redox Signal. 18, 1400–1417. PMID:22746273

  10. Ammonia and NO/NOx measurement for DE-NOx applications

    SciTech Connect

    Kita, D.

    1996-10-01

    A number of critical environmental goals may be met by controlling nitrogen oxide (NOx) emissions from combustion sources. These goals include responding to 1990 Clean Air Act Amendment requirements, reduction of human exposure to harmful concentrations of nitric oxide (NO) and nitrogen dioxide (NO{sub 2}), acid deposition control, and urban smog abatement. Technologies utilizing either heterogeneous or homogeneous reactions of NOx with ammonia (NH{sub 3}) are considered major control options. Crucial to the use of such technologies is the continuous measurement of NO/NOx and NH{sub 3} in order to access (and control) performance criteria such as NOx conversion efficiency and NH{sub 3} emissions (NH{sub 3} SLIP) .This paper describes a continuous emission sonitoring system for NO, NO{sub 2}, and NH{sub 3} based upon NO chemiluminescence as well as presenting preliminary field data.

  11. Sestrin 2 and AMPK Connect Hyperglycemia to Nox4-Dependent Endothelial Nitric Oxide Synthase Uncoupling and Matrix Protein Expression

    PubMed Central

    Eid, Assaad A.; Lee, Doug-Yoon; Roman, Linda J.; Khazim, Khaled

    2013-01-01

    Mesangial matrix accumulation is an early feature of glomerular pathology in diabetes. Oxidative stress plays a critical role in hyperglycemia-induced glomerular injury. Here, we demonstrate that, in glomerular mesangial cells (MCs), endothelial nitric oxide synthase (eNOS) is uncoupled upon exposure to high glucose (HG), with enhanced generation of reactive oxygen species (ROS) and decreased production of nitric oxide. Peroxynitrite mediates the effects of HG on eNOS dysfunction. HG upregulates Nox4 protein, and inhibition of Nox4 abrogates the increase in ROS and peroxynitrite generation, as well as the eNOS uncoupling triggered by HG, demonstrating that Nox4 functions upstream from eNOS. Importantly, this pathway contributes to HG-induced MC fibronectin accumulation. Nox4-mediated eNOS dysfunction was confirmed in glomeruli of a rat model of type 1 diabetes. Sestrin 2-dependent AMP-activated protein kinase (AMPK) activation attenuates HG-induced MC fibronectin synthesis through blockade of Nox4-dependent ROS and peroxynitrite generation, with subsequent eNOS uncoupling. We also find that HG negatively regulates sestrin 2 and AMPK, thereby promoting Nox4-mediated eNOS dysfunction and increased fibronectin. These data identify a protective function for sestrin 2/AMPK and potential targets for intervention to prevent fibrotic injury in diabetes. PMID:23816887

  12. NOx Emission Reduction by Oscillating Combustion

    SciTech Connect

    2005-09-01

    This project focuses on a new technology that reduces NOx emissions while increasing furnace efficiency for both air- and oxygen-fired furnaces. Oscillating combustion is a retrofit technology that involves the forced oscillation of the fuel flow rate to a furnace. These oscillations create successive, fuel-rich and fuel-lean zones within the furnace.

  13. Low NOx heavy fuel combustor concept program

    NASA Technical Reports Server (NTRS)

    White, D. J.; Lecren, R. T.; Batakis, A. P.

    1981-01-01

    A total of twelve low NOx combustor configurations, embodying three different combustion concepts, were designed and fabricated as modular units. These configurations were evaluated experimentally for exhaust emission levels and for mechanical integrity. Emissions data were obtained in depth on two of the configurations.

  14. 40 CFR 96.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 96.388 Section 96.388 Protection of Environment... SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Ozone Season Opt-in Units § 96.388...

  15. 40 CFR 96.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 96.388 Section 96.388 Protection of Environment... SO 2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Ozone Season Opt-in Units § 96.388...

  16. 40 CFR 96.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 96.388 Section 96.388 Protection of Environment... SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Ozone Season Opt-in Units § 96.388...

  17. 40 CFR 96.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 96.388 Section 96.388 Protection of Environment... SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Ozone Season Opt-in Units § 96.388...

  18. 40 CFR 96.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 96.388 Section 96.388 Protection of Environment... SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Ozone Season Opt-in Units § 96.388...

  19. 40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and heat input for the purpose of calculating NOX mass emissions. 75.71 Section 75.71 Protection of... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for... and for a flow monitoring system and an O2 or CO2 diluent gas monitoring system to measure heat...

  20. 40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and heat input for the purpose of calculating NOX mass emissions. 75.71 Section 75.71 Protection of... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for... and for a flow monitoring system and an O2 or CO2 diluent gas monitoring system to measure heat...

  1. 40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and heat input for the purpose of calculating NOX mass emissions. 75.71 Section 75.71 Protection of... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for... and for a flow monitoring system and an O2 or CO2 diluent gas monitoring system to measure heat...

  2. Role of Nox4 in murine models of kidney disease.

    PubMed

    Babelova, Andrea; Avaniadi, Despina; Jung, Oliver; Fork, Christian; Beckmann, Janet; Kosowski, Judith; Weissmann, Norbert; Anilkumar, Narayana; Shah, Ajay M; Schaefer, Liliana; Schröder, Katrin; Brandes, Ralf P

    2012-08-15

    Nox4 is a hydrogen peroxide-producing NADPH oxidase highly expressed in the kidney which has been linked to epithelial cell injury and diabetic-induced cellular dysfunction in cultured cells. The role of the enzyme for renal pathology in vivo, however, is unclear. To address this, three experimental animal models of renal injury (streptozotocin diabetes I, unilateral ureteral ligation (UUO), and 5/6 nephrectomy (5/6Nx)) were studied in either Nox4-inducible (Nox4(*/*)) or constitutive knockout (Nox4(-/-)) mice. Nox4 contributed more than 80% of diphenylene iodonium-sensitive H(2)O(2) formation of freshly isolated tubules determined by Amplex Red assay. In streptozotocin diabetes, acute deletion of Nox4 by tamoxifen-activated cre-recombinase increased albuminuria, whereas matrix deposition was similar between WT and Nox4(*/*) mice. Interestingly, renal Nox4 expression, mainly localized to tubular cells, decreased in the course of diabetes and this was not associated with a compensatory upregulation of Nox1 or Nox2. In the UUO model, renal expression of ICAM1, connective tissue growth factor, and fibronectin were higher in kidneys of Nox4(*/*) than control mice. Also in this model, levels of Nox4 decreased in the course of the disease. In the 5/6Nx model, which was performed in SV129 and SV129-Nox4(-/-) mice, no difference in the development of hypertension and albuminuria was found between the strains. Collectively, the first in vivo data of the kidney do not support the view that Nox4 is a main driver of renal disease. It rather appears that under specific conditions Nox4 may even slightly limit injury and disease progression.

  3. DEVELOPMENT AND DEMONSTRATION OF NOVEL LOW-NOx BURNERS IN THE STEEL INDUSTRY

    SciTech Connect

    Cygan, David

    2006-12-28

    Gas Technology Institute (GTI), together with Hamworthy Peabody Combustion Incorporated (formerly Peabody Engineering Corporation), the University of Utah, and Far West Electrochemical have developed and demonstrated an innovative combustion system suitable for natural gas and coke-oven gas firing within the steel industry. The combustion system is a simple, low-cost, energy-efficient burner that can reduce NOx by more than 75%. The U.S. steel industry needs to address NOx control at its steelmaking facilities. A significant part of NOx emissions comes from gas-fired boilers. In steel plants, byproduct gases – blast furnace gas (BFG) and coke-oven gas (COG) – are widely used together with natural gas to fire furnaces and boilers. In steel plants, natural gas can be fired together with BFG and COG, but, typically, the addition of natural gas raises NOx emissions, which can already be high because of residual fuel-bound nitrogen in COG. The Project Team has applied its expertise in low-NOx burners to lower NOx levels for these applications by combining advanced burner geometry and combustion staging with control strategies tailored to mixtures of natural gas and byproduct fuel gases. These methods reduce all varieties of NOx – thermal NOx produced by high flame temperatures, prompt NOx produced by complex chain reactions involving radical hydrocarbon species and NOx from fuel-bound nitrogen compounds such as ammonia found in COG. The Project Team has expanded GTI’s highly successful low-NOx forced internal recirculation (FIR) burner, previously developed for natural gas-fired boilers, into facilities that utilize BFG and COG. For natural gas firing, these burners have been shown to reduce NOx emissions from typical uncontrolled levels of 80-100 vppm to single-digit levels (9 vppm). This is done without the energy efficiency penalties incurred by alternative NOx control methods, such as external flue gas recirculation (FGR), water injection, and selective non

  4. SNOW2002: NOx Production From Nitrate-In-Ice Photolysis at Two pHs and Comparison with NOx Levels From Nitrite-In-Ice Photolysis

    NASA Astrophysics Data System (ADS)

    Peterson, M.; Dibb, J.

    2002-12-01

    We conducted experiments using artificial snow, synthetic air, and sunlight during January, 2002 (the SNOW2002 study) in order to test the influence of neutral and basic pH on the amount of NO, NO2, and NOx emitted from artificial snow during nitrate photolysis. We also conducted the first tests demonstrating that illumination of consolidated, sub-millimeter diameter ice particles (e.g., artificial snow) doped with nitrite produces NOx, confirming that nitrite photolysis occurs in ice and snow. Innovations in NOx instrument design were also implemented in order to estimate gaseous HONO levels using UV lamp photolysis. Nitrate was introduced into solution as sodium nitrate, pH was controlled using sodium hydroxide. Artificial snow particles were formed by spraying tiny water droplets down into a tall (3 meter) column chilled by a pool of liquid nitrogen at the column base. Although this method of creating artificial snow results in snow that is certainly different than natural snow, the tiny ice particles formed are powdery and sinter quickly. This artificial snow is relatively easy to make and is well suited for determining whether photolysis of nitrate or nitrite is occurring, and whether changes occur at various pH levels. The amounts of NO and NO2 produced by nitrate ion photolysis in aqueous solution depends on pH such that NO production is greatly enhanced in basic solutions. Our preliminary results indicate that the pH of the solutions used to make artificial snow does not effect the levels or partitioning of NOx produced from nitrate-in-ice photolysis. This result suggests that aqueous photochemical analogs of nitrate photolysis may not apply to nitrate-in-ice photochemistry and that more experiments are needed in order to understand nitrate-in-ice photochemistry. Experiments exploring nitrite-in-ice photolysis demonstrate that there is one to two orders of magnitude more NOx produced by nitrite photolysis than by nitrate photolysis at equivalent conditions

  5. THE LIQUID AND GASEOUS FUEL DISTRIBUTION SYSTEM

    EPA Science Inventory

    The report describes the national liquid and gaseous fuel distribution system. he study leading to the report was performed as part of an effort to better understand emissions of volatile organic compounds from the fuel distribution system. he primary, secondary, and tertiary seg...

  6. Methods and systems for deacidizing gaseous mixtures

    DOEpatents

    Hu, Liang

    2010-05-18

    An improved process for deacidizing a gaseous mixture using phase enhanced gas-liquid absorption is described. The process utilizes a multiphasic absorbent that absorbs an acid gas at increased rate and leads to reduced overall energy costs for the deacidizing operation.

  7. AMMONIA-FREE NOx CONTROL SYSTEM

    SciTech Connect

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2006-06-01

    This report describes a novel NOx control system that has the potential to drastically reduce cost, and enhance performance, operation and safety of power plant NOx control. The new system optimizes the burner and the furnace to achieve very low NOx levels and to provide an adequate amount of CO, and uses the CO for reducing NO both in-furnace and over a downstream AFSCR (ammonia-free selective catalytic reduction) reactor. The AF-SCR combines the advantages of the highly successful SCR technology for power plants and the TWC (three-way catalytic converter) widely used on automobiles. Like the SCR, it works in oxidizing environment of combustion flue gas and uses only base metal catalysts. Like the TWC, the AF-SCR removes NO and excess CO simultaneously without using any external reagent, such as ammonia. This new process has been studied in a development program jointed funded by the US Department of Energy and Foster Wheeler. The report outlines the experimental catalyst work performed on a bench-scale reactor, including test procedure, operating conditions, and results of various catalyst formulations. Several candidate catalysts, prepared with readily available transition metal oxides and common substrate materials, have shown over 80-90% removal for both NO and CO in oxidizing gas mixtures and at elevated temperatures. A detailed combustion study of a 400 MWe coal-fired boiler, applying computational fluid dynamics techniques to model boiler and burner design, has been carried out to investigate ways to optimize the combustion process for the lowest NOx formation and optimum CO/NO ratios. Results of this boiler and burner optimization work are reported. The paper further discusses catalyst scale-up considerations and the conceptual design of a 400 MWe size AF-SCR reactor, as well as economics analysis indicating large cost savings of the ammonia-free NOx control process over the current SCR technology.

  8. NOx Sensor for Direct Injection Emission Control

    SciTech Connect

    Betteridge, William J

    2006-02-28

    The Electricore/Delphi team continues to leverage the electrochemical planar sensor technology that has produced stoichiometric planar and wide range oxygen sensors as the basis for development of a NOx sensor. Zirconia cell technology with an integrated heater will provide the foundation for the sensor structure. Proven materials and packaging technology will help to ensure a cost-effective approach to the manufacture of this sensor. The electronics technique and interface is considered to be an area where new strategies need to be employed to produce higher S/N ratios of the NOx signal with emphasis on signal stability over time for robustness and durability Both continuous mode and pulse mode control techniques are being evaluated. Packaging the electronics requires careful design and circuit partitioning so that only the necessary signal conditioning electronics are coupled directly in the wiring harness, while the remainder is situated within the ECM for durability and costs reasons. This task continues to be on hold due to the limitation that the definition of the interface electronics was unavailable until very late in the project. The sense element is based on the amperometric method utilizing integrated alumina and zirconia ceramics. Precious metal electrodes are used to form the integrated heater, the cell electrodes and leads. Inside the actual sense cell structure, it is first necessary to separate NOx from the remaining oxygen constituents of the exhaust, without reducing the NOx. Once separated, the NOx will be measured using a measurement cell. Development or test coupons have been used to facilitate material selection and refinement, cell, diffusion barrier, and chamber development. The sense element currently requires elaborate interconnections. To facilitate a robust durable connection, mechanical and metallurgical connections are under investigation. Materials and process refinements continue to play an important role in the development of the

  9. Effect of Hypergravity Stress on Gaseous Exchange and Survival of Young and Old Guinea Pigs

    NASA Astrophysics Data System (ADS)

    Muradian, Kh. K.; Timchenko, A. N.

    Hypergravity tolerance decreases in aging Guinea pigs, the range being lower than in other studied species of laboratory mammals - mice, hamsters, and rats. Moreover, for the gaseous exchange rate and body temperature, the decline during the stress is not characteristic for Guinea pigs of both age groups, in contrast to other species. In general, hypergravity tolerance of Guinea pigs could be more appropriate experimental models.

  10. Method and apparatus for producing laser radiation following two-photon excitation of a gaseous medium

    DOEpatents

    Bischel, W.K.; Jacobs, R.R.; Prosnitz, D.P.; Rhodes, C.K.; Kelly, P.J.

    1979-02-20

    Method and apparatus are disclosed for producing laser radiation by two-photon optical pumping of an atomic or molecular gaseous medium and subsequent lasing action. A population inversion is created as a result of two-photon absorption of the gaseous species. Stark tuning is utilized, if necessary, in order to tune the two-photon transition into exact resonance. In particular, gaseous ammonia (NH[sub 3]) or methyl fluoride (CH[sub 3]F) is optically pumped by a pair of CO[sub 2] lasers to create a population inversion resulting from simultaneous two-photon excitation of a high-lying vibrational state, and laser radiation is produced by stimulated emission of coherent radiation from the inverted level. 3 figs.

  11. Method and apparatus for producing laser radiation following two-photon excitation of a gaseous medium

    DOEpatents

    Bischel, William K. [Menlo Park, CA; Jacobs, Ralph R. [Livermore, CA; Prosnitz, Donald [Hamden, CT; Rhodes, Charles K. [Palo Alto, CA; Kelly, Patrick J. [Fort Lewis, WA

    1979-02-20

    Method and apparatus for producing laser radiation by two-photon optical pumping of an atomic or molecular gaseous medium and subsequent lasing action. A population inversion is created as a result of two-photon absorption of the gaseous species. Stark tuning is utilized, if necessary, in order to tune the two-photon transition into exact resonance. In particular, gaseous ammonia (NH.sub.3) or methyl fluoride (CH.sub.3 F) is optically pumped by a pair of CO.sub.2 lasers to create a population inversion resulting from simultaneous two-photon excitation of a high-lying vibrational state, and laser radiation is produced by stimulated emission of coherent radiation from the inverted level.

  12. Modelling the dynamics of plasma in gaseous channels during streamer propagation in hydrocarbon liquids

    NASA Astrophysics Data System (ADS)

    Naidis, G. V.

    2016-06-01

    A numerical model is developed and the calculation results of plasma dynamics in gaseous channels of streamers propagating in hydrocarbon liquids are presented. It is shown that, due to Joule heating leading to a reduction of the gas density, the local electric field, governed by the ionization-recombination balance of charged species, decreases along the channel. As a result, the mean electric field in long gaseous channels decreases with the growth of channel length. Correspondingly, the calculated length of streamer propagation (stopping length) increases with applied voltage faster than linearly, in accordance with experimental data. Calculated values of the mean electric field in long gaseous channels agree with those obtained in experiments on streamer propagation in long gaps.

  13. Impacts of a Nanosized Ceria Additive on Diesel Engine Emissions of Particulate and Gaseous Pollutants

    PubMed Central

    Zhang, Junfeng; Nazarenko, Yevgen; Zhang, Lin; Calderon, Leonardo; Lee, Ki-Bum; Garfunkel, Eric; Schwander, Stephan; Tetley, Teresa D.; Chung, Kian Fan; Porter, Alexandra E.; Ryan, Mary; Kipen, Howard; Lioy, Paul J.; Mainelis, Gediminas

    2014-01-01

    Fuel additives incorporating nanosized ceria have been increasingly used in diesel engines as combustion promoters. However, few studies have assessed the impact of these nanotechnology-based additives on pollutant emissions. Here, we systematically compare emission rates of particulate and gaseous pollutants from a single-cylinder, four-cycle diesel engine using fuel mixes containing nanoceria of varying concentrations. The test fuels were made by adding different amounts of a commercial fuel additive Envirox into an ultralow-sulfur diesel fuel at 0 (base fuel), 0.1-, 1-, and 10-fold the manufacturer-recommended concentration of 0.5 mL Envirox per liter of fuel. The addition of Envirox resulted in ceria-concentration-dependent emission reductions of CO2, CO, total particulate mass, formaldehyde, acetaldehyde, acrolein, and several polycyclic aromatic hydrocarbons. These reductions at the manufacturer-recommended doping concentration, however, were accompanied by a substantial increase of certain other air pollutants, specifically the number of ultrafine particles (+32%), NOx (+9.3%), and the particle-phase benzo[a]pyrene toxic equivalence quotient (+35%). Increasing fuel ceria concentrations also led to decreases in the size of emitted particles. Given health concerns related to ultrafine particles and NOx, our findings call for additional studies to further evaluate health risks associated with the use of nanoceria additives in various engines under various operating conditions. PMID:24144266

  14. Impacts of a nanosized ceria additive on diesel engine emissions of particulate and gaseous pollutants.

    PubMed

    Zhang, Junfeng; Nazarenko, Yevgen; Zhang, Lin; Calderon, Leonardo; Lee, Ki-Bum; Garfunkel, Eric; Schwander, Stephan; Tetley, Teresa D; Chung, Kian Fan; Porter, Alexandra E; Ryan, Mary; Kipen, Howard; Lioy, Paul J; Mainelis, Gediminas

    2013-11-19

    Fuel additives incorporating nanosized ceria have been increasingly used in diesel engines as combustion promoters. However, few studies have assessed the impact of these nanotechnology-based additives on pollutant emissions. Here, we systematically compare emission rates of particulate and gaseous pollutants from a single-cylinder, four-cycle diesel engine using fuel mixes containing nanoceria of varying concentrations. The test fuels were made by adding different amounts of a commercial fuel additive Envirox into an ultralow-sulfur diesel fuel at 0 (base fuel), 0.1-, 1-, and 10-fold the manufacturer-recommended concentration of 0.5 mL Envirox per liter of fuel. The addition of Envirox resulted in ceria-concentration-dependent emission reductions of CO2, CO, total particulate mass, formaldehyde, acetaldehyde, acrolein, and several polycyclic aromatic hydrocarbons. These reductions at the manufacturer-recommended doping concentration, however, were accompanied by a substantial increase of certain other air pollutants, specifically the number of ultrafine particles (+32%), NO(x) (+9.3%), and the particle-phase benzo[a]pyrene toxic equivalence quotient (+35%). Increasing fuel ceria concentrations also led to decreases in the size of emitted particles. Given health concerns related to ultrafine particles and NO(x), our findings call for additional studies to further evaluate health risks associated with the use of nanoceria additives in various engines under various operating conditions.

  15. Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel

    DOEpatents

    Steele, Robert C; Edmonds, Ryan G; Williams, Joseph T; Baldwin, Stephen P

    2012-11-20

    A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

  16. Vortex combustor for low NOx emissions when burning lean premixed high hydrogen content fuel

    DOEpatents

    Steele, Robert C.; Edmonds, Ryan G.; Williams, Joseph T.; Baldwin, Stephen P.

    2009-10-20

    A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

  17. Gaseous fuel and air proportioning device

    SciTech Connect

    Lassanske, G. G.; Poshlman, A. G.

    1984-01-10

    The device for proportioning a gaseous fuel and air for combustion in an internal combustion engine includes a plate-like first member having a peripheral edge portion and a second member cooperating with the first member having a peripheral edge portion and a second member cooperating with the first member to define a mixing chamber having an outlet adapted to be connected in communication with the air intake of the engine carburetor. The second member also includes an annular portion having an arcuate first wall which is convex to and spaced from the peripheral edge portion of the first member to define an annular venturi having an inlet in communication with the atmosphere and an annular outlet in communication with the mixing chamber. A base member or second wall cooperates with the arcuate wall to form a substantially closed, annular plenum chamber into which a gaseous fuel, such as natural gas, is admitted when the engine is to be operated on the gaseous fuel. The gaseous fuel is admitted into the mixing chamber from the plenum chamber through one or more ports in the arcuate wall at or in the vicinity of the throat of the annular venturi. A pair of circumferentially spaced radially extending partitions located on the opposite sides of each port define a radially extending venturi which has a throat located at or in the vicinity of the port and serves to induce flow of the gaseous fuel through the corresponding port. The proportioning device preferably is arranged to fit inside the housing of an existing air cleaner.

  18. Experimental Evaluation of a Subscale Gaseous Hydrogen/Gaseous Oxygen Coaxial Rocket Injector

    NASA Astrophysics Data System (ADS)

    Smith, Timothy D.; Klem, Mark D.; Breisacher, Kevin J.; Farhangi, Shahram; Sutton, Robert

    2002-11-01

    The next generation reusable launch vehicle may utilize a Full-Flow Stage Combustion (FFSC) rocket engine cycle. One of the key technologies required is the development of an injector that uses gaseous oxygen and gaseous hydrogen as propellants. Gas-gas propellant injection provides an engine with increased stability margin over a range of throttle set points. This paper summarizes an injector design and testing effort that evaluated a coaxial rocket injector for use with gaseous oxygen and gaseous hydrogen propellants. A total of 19 hot-fire tests were conducted up to a chamber pressure of 1030 psia, over a range of 3.3 to 6.7 for injector element mixture ratio. Post-test condition of the hardware was also used to assess injector face cooling. Results show that high combustion performance levels could be achieved with gas-gas propellants and there were no problems with excessive face heating for the conditions tested.

  19. Experimental Evaluation of a Subscale Gaseous Hydrogen/gaseous Oxygen Coaxial Rocket Injector

    NASA Technical Reports Server (NTRS)

    Smith, Timothy D.; Klem, Mark D.; Breisacher, Kevin J.; Farhangi, Shahram; Sutton, Robert

    2002-01-01

    The next generation reusable launch vehicle may utilize a Full-Flow Stage Combustion (FFSC) rocket engine cycle. One of the key technologies required is the development of an injector that uses gaseous oxygen and gaseous hydrogen as propellants. Gas-gas propellant injection provides an engine with increased stability margin over a range of throttle set points. This paper summarizes an injector design and testing effort that evaluated a coaxial rocket injector for use with gaseous oxygen and gaseous hydrogen propellants. A total of 19 hot-fire tests were conducted up to a chamber pressure of 1030 psia, over a range of 3.3 to 6.7 for injector element mixture ratio. Post-test condition of the hardware was also used to assess injector face cooling. Results show that high combustion performance levels could be achieved with gas-gas propellants and there were no problems with excessive face heating for the conditions tested.

  20. Commercial introduction of the Advanced NOxTECH system

    SciTech Connect

    Sudduth, B.C.

    1997-12-31

    NOxTECH is BACT for diesel electric generators. Emissions of NO{sub x} are reduced 95% or more with substantial concurrent reductions in CO, particulates, and ROG`s. No engine modifications or other exhaust aftertreatments can remove all criteria pollutants as effectively as NOxTECH. The NOxTECH system reliably maintains NH{sub 3} slip below 2 ppm. Unlike other emissions controls, NOxTECH does not generate hazardous by-products. The Advanced NOxTECH system reduces the size, weight, and cost for BACT emissions reductions. Based on the operation of a 150 kW prototype, NOxTECH, Inc. is quoting commercial units for diesel electric generators. Advanced NOxTECH equipment costs about half as much as SCR systems, and NO{sub x} reduction can exceed 95% with guarantees for emissions compliance.

  1. NOX4 NADPH Oxidase-Dependent Mitochondrial Oxidative Stress in Aging-Associated Cardiovascular Disease

    PubMed Central

    Vendrov, Aleksandr E.; Vendrov, Kimberly C.; Smith, Alberto; Yuan, Jinling; Sumida, Arihiro; Robidoux, Jacques; Madamanchi, Nageswara R.

    2015-01-01

    Abstract Aims: Increased oxidative stress and vascular inflammation are implicated in increased cardiovascular disease (CVD) incidence with age. We and others demonstrated that NOX1/2 NADPH oxidase inhibition, by genetic deletion of p47phox, in Apoe−/− mice decreases vascular reactive oxygen species (ROS) generation and atherosclerosis in young age. The present study examined whether NOX1/2 NADPH oxidases are also pivotal to aging-associated CVD. Results: Both aged (16 months) Apoe−/− and Apoe−/−/p47phox−/− mice had increased atherosclerotic lesion area, aortic stiffness, and systolic dysfunction compared with young (4 months) cohorts. Cellular and mitochondrial ROS (mtROS) levels were significantly higher in aortic wall and vascular smooth muscle cells (VSMCs) from aged wild-type and p47phox−/− mice. VSMCs from aged mice had increased mitochondrial protein oxidation and dysfunction and increased vascular cell adhesion molecule 1 expression, which was abrogated with (2-(2,2,6,6-Tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl)triphenylphosphonium chloride (MitoTEMPO) treatment. NOX4 expression was increased in the vasculature and mitochondria of aged mice and its suppression with shRNA in VSMCs from aged mice decreased mtROS levels and improved function. Increased mtROS levels were associated with enhanced mitochondrial NOX4 expression in aortic VSMCs from aged subjects, and NOX4 expression levels in arterial wall correlated with age and atherosclerotic severity. Aged Apoe−/− mice treated with MitoTEMPO and 2-(2-chlorophenyl)-4-methyl-5-(pyridin-2-ylmethyl)-1H-pyrazolo[4,3-c]pyridine-3,6(2H,5H)-dione had decreased vascular ROS levels and atherosclerosis and preserved vascular and cardiac function. Innovation and Conclusion: These data suggest that NOX4, but not NOX1/2, and mitochondrial oxidative stress are mediators of CVD in aging under hyperlipidemic conditions. Regulating NOX4 activity/expression and using mitochondrial antioxidants are

  2. Electrochemical NOx Sensor for Monitoring Diesel Emissions

    SciTech Connect

    Woo, L Y; Glass, R S

    2008-11-14

    % NO, balance NO{sub 2}. Since automotive exhaust sensors will probably be required to operate at temperatures > 600 C, NO is the dominant component in thermodynamic equilibrium and the target NOx species. Also, the use of upstream catalysts could further promote the conversion of NO{sub x} species to NO. Therefore, the focus of current work is to investigate the response to NO. Nevertheless, minimizing the sensitivity to a variety of competing species is important in order to obtain the accuracy necessary for achieving the emission limits. Mitigating the effect of interfering gases (e.g., O{sub 2}, water vapor, HCs, etc.) is an area of current study. For impedance metric NO{sub x} sensors, our previous work has demonstrated that the cross-sensitivity to O{sub 2} may be accounted for by comparing measurements at multiple frequencies. Other strategies for compensation are also being explored, including calibration using data from existing sensors located nearby. Our current work has made significant advances in terms of developing prototype sensors more suitable for commercialization. Also, dynamometer testing has provided real-world sensor performance data that will be useful in approaching potential suppliers to whom we can transfer the technology for commercialization. The advances are a direct result of understanding the sensing mechanisms responsible for impedance-based NO{sub x} sensing and the effect of materials choice and sensor design/geometry.

  3. Airborne Measurements of NOx, NOy, and O3 Using Cavity Ring-Down Spectroscopy

    NASA Astrophysics Data System (ADS)

    Zarzana, K. J.; Wild, R. J.; Thompson, C. R.; Sjostedt, S. J.; Womack, C. C.; Washenfelder, R. A.; Dube, W. P.; Ryerson, T. B.; Brown, S. S.

    2015-12-01

    NO and NO2 (=NOx) have a large effect on air quality and chemistry. Oxidation reactions transform NOx into other reactive nitrogen species such as PAN, HNO3, organic nitrates and N2O5, which can act either as sinks or reservoirs of NOx. Together with NOx, the sum of these oxidized reactive nitrogen species is termed NOy. Ozone serves as a principal oxidant source for many of these reactions, and it is also produced or destroyed during subsequent chemical cycles. Therefore, simultaneous measurements of all four species (NO, NO2, NOy, and O3) are desirable. Previous measurements of these species have principally been made by converting the compound of interest to NO, which is then detected using chemiluminescence. Alternatively, these species can be converted to NO2, which can then be detected using absorption spectroscopy. The use of a cavity ring down instrument allows for the accurate and rapid detection of NO2 in a compact and robust platform suitable for field deployments on numerous platforms, including vehicles and airplanes. In this work we describe the first aircraft deployment of a four-channel cavity ring-down instrument capable of simultaneously measuring NO2, NO, NOy, and O3. This deployment took place during the 2015 Shale Oil and Natural Gas Nexus (SONGNEX) field campaign in the western United States. The instrument flew in tandem with a chemiluminescence instrument, which measured the same set of compounds. A separate instrument that measured NO2 by a related absorption technique, broadband cavity enhanced spectroscopy (BBCES) was also on board the aircraft. An intercomparison between these instruments will be presented, as well as data from the SONGNEX flights that illustrate the capabilities of the CRDS insrument.

  4. 40 CFR 89.417 - Data evaluation for gaseous emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Emission Test Procedures § 89.417 Data evaluation for gaseous emissions. For the evaluation of the gaseous emission recording, the last 60 seconds of each mode are recorded, and the average values for HC, CO,...

  5. Mixing and NOx Emission Calculations of Confined Reacting Jet Flows in Cylindrical and Annular Ducts

    NASA Technical Reports Server (NTRS)

    Oechsle, Victor L.; Connor, Christopher H.; Holdeman, James D. (Technical Monitor)

    2000-01-01

    Rapid mixing of cold lateral jets with hot cross-stream flows in confined configurations is of practical interest in gas turbine combustors as it strongly affects combustor exit temperature quality, and gaseous emissions in for example rich-lean combustion. It is therefore important to further improve our fundamental understanding of the important processes of dilution jet mixing especially when the injected jet mass flow rate exceeds that of the cross-stream. The results reported in this report describe some of the main flow characteristics which develop in the mixing process in a cylindrical duct. A three-dimensional computational fluid dynamics (CFD) code has been used to predict the mixing flow field characteristics and NOx emission in a quench section of a rich-burn/quick-mix/lean-burn (RQL) combustor. Sixty configurations have been analyzed in both circular and annular geometries in a fully reacting environment simulating the operating condition of an actual RQL gas turbine combustion liner. The evaluation matrix was constructed by varying the number of orifices per row and orifice shape. Other parameters such as J (momentum-flux ratio), MR (mass flowrate ratio), DR (density ratio), and mixer sector orifice ACd (effective orifice area) were maintained constant throughout the entire study. The results indicate that the mixing flow field can be correlated with the NOx production if they are referenced with the stoichiometric equivalence ratio value and not the equilibrium value. The mixing flowfields in both circular and annular mixers are different. The penetration of equal jets in both annular and circular geometries is vastly different which significantly affects the performance of the mixing section. In the computational results with the circular mixer, most of the NOx formation occurred behind the orifice starting at the orifice wake region. General trends have been observed in the NOx production as the number of orifices is changed and this appears to be

  6. Compositional and stable carbon isotopic fractionation during non-autocatalytic thermochemical sulfate reduction by gaseous hydrocarbons

    USGS Publications Warehouse

    Xia, Xinyu; Ellis, Geoffrey S.; Ma, Qisheng; Tang, Yongchun

    2014-01-01

    The possibility of autocatalysis during thermochemical sulfate reduction (TSR) by gaseous hydrocarbons was investigated by examination of previously reported laboratory and field data. This reaction was found to be a kinetically controlled non-autocatalytic process, and the apparent lack of autocatalysis is thought to be due to the absence of the required intermediate species. Kinetic parameters for chemical and carbon isotopic fractionations of gaseous hydrocarbons affected by TSR were calculated and found to be consistent with experimentally derived values for TSR involving long-chain hydrocarbons. Model predictions based on these kinetic values indicate that TSR by gaseous hydrocarbon requires high-temperature conditions. The oxidation of C2–5 hydrocarbons by sulfate reduction is accompanied by carbon isotopic fractionation with the residual C2–5 hydrocarbons becoming more enriched in 13C. Kinetic parameters were calculated for the stable carbon isotopic fractionation of gaseous hydrocarbons that have experienced TSR. Model predictions based on these kinetics indicate that it may be difficult to distinguish the effects of TSR from those of thermal maturation at lower levels of hydrocarbon oxidation; however, unusually heavy δ13C2+ values (>−10‰) can be diagnostic of high levels of conversion (>50%). Stoichiometric and stable carbon isotopic data show that methane is stable under the investigated reaction conditions and is likely a product of TSR by other gaseous hydrocarbons rather than a significant reactant. These results indicate that the overall TSR reaction mechanism for oxidation of organic substrates containing long-chain hydrocarbons involves three distinct phases as follows: (1) an initial slow and non-autocatalytic stage characterized by the reduction of reactive sulfate by long-chain saturated hydrocarbons; (2) a second autocatalytic reaction phase dominated by reactions involving reduced sulfur species and partially oxidized hydrocarbons; (3

  7. Acute restraint stress increases carotid reactivity in type-I diabetic rats by enhancing Nox4/NADPH oxidase functionality.

    PubMed

    Moreira, Josimar D; Pernomian, Larissa; Gomes, Mayara S; Pernomian, Laena; Moreira, Rafael P; do Prado, Alejandro F; da Silva, Carlos H T P; de Oliveira, Ana M

    2015-10-15

    Hyperglycemia increases the generation of reactive oxygen species and affects systems that regulate the vascular tone including renin-angiotensin system. Stress could exacerbate intracellular oxidative stress during Diabetes upon the activation of angiotensin AT1/NADPH oxidase pathway, which contributes to the development of diabetic cardiovascular complications. For this study, type-I Diabetes was induced in Wistar rats by intraperitoneal injection of streptozotocin. 28 days after streptozotocin injection, the animals underwent to acute restraint stress for 3 h. Cumulative concentration-response curves for angiotensin II were obtained in carotid rings pre-treated or not with Nox or cyclooxygenase inhibitors. Nox1 or Nox4 expression and activity were assessed by Western blotting and lucigenin chemiluminescence, respectively. The role of Nox1 and Nox4 on reactive oxygen species generation was evaluated by flow cytometry and Amplex Red assays. Cyclooxygenases expression was assessed by real-time polymerase chain reaction. The contractile response evoked by angiotensin II was increased in diabetic rat carotid. Acute restraint stress increased this response in this vessel by mechanisms mediated by Nox4, whose local expression and activity in generating hydrogen peroxide are increased. The contractile hyperreactivity to angiotensin II in stressed diabetic rat carotid is also mediated by metabolites derived from cyclooxygenase-2, whose local expression is increased. Taken together, our findings suggest that acute restraint stress exacerbates the contractile hyperreactivity to angiotensin II in diabetic rat carotid by enhancing Nox4-driven generation of hydrogen peroxide, which evokes contractile tone by cyclooxygenases-dependent mechanisms. Finally, these findings highlight the harmful role played by acute stress in modulating diabetic vascular complications. PMID:26387612

  8. ULTRA LOW NOx INTEGRATED SYSTEM FOR NOx EMISSION CONTROL FROM COAL-FIRED BOILERS

    SciTech Connect

    Galen H. Richards; Charles Q. Maney; Richard W. Borio; Robert D. Lewis

    2002-12-30

    ALSTOM Power Inc.'s Power Plant Laboratories, working in concert with ALSTOM Power's Performance Projects Group, has teamed with the U.S. Department of Energy's National Energy Technology Laboratory (DOE NETL) to conduct a comprehensive study to develop/evaluate low-cost, efficient NOx control technologies for retrofit to pulverized coal fired utility boilers. The objective of this project was to develop retrofit NOx control technology to achieve less than 0.15 lb/MMBtu NOx (for bituminous coals) and 0.10 lb/MMBtu NOx (for subbituminous coals) from existing pulverized coal fired utility boilers at a cost which is at least 25% less than SCR technology. Efficient control of NOx is seen as an important, enabling step in keeping coal as a viable part of the national energy mix in this century, and beyond. Presently 57% of U.S. electrical generation is coal based, and the Energy Information Agency projects that coal will maintain a lead in U.S. power generation over all other fuel sources for decades (EIA 1998 Energy Forecast). Yet, coal-based power is being strongly challenged by society's ever-increasing desire for an improved environment and the resultant improvement in health and safety. The needs of the electric-utility industry are to improve environmental performance, while simultaneously improving overall plant economics. This means that emissions control technology is needed with very low capital and operating costs. This project has responded to the industry's need for low NOx emissions by evaluating ideas that can be adapted to present pulverized coal fired systems, be they conventional or low NOx firing systems. The TFS 2000{trademark} firing system has been the ALSTOM Power Inc. commercial offering producing the lowest NOx emission levels. In this project, the TFS 2000{trademark} firing system served as a basis for comparison to other low NOx systems evaluated and was the foundation upon which refinements were made to further improve NOx emissions and

  9. Nox2 contributes to the arterial endothelial specification of mouse induced pluripotent stem cells by upregulating Notch signaling

    PubMed Central

    Kang, Xueling; Wei, Xiangxiang; Wang, Xinhong; Jiang, Li; Niu, Cong; Zhang, Jianyi; Chen, Sifeng; Meng, Dan

    2016-01-01

    Reactive oxygen species (ROS) have a crucial role in stem-cell differentiation; however, the mechanisms by which ROS regulate the differentiation of stem cells into endothelial cells (ECs) are unknown. Here, we determine the role of ROS produced by NADPH oxidase 2 (Nox2) in the endothelial-lineage specification of mouse induced-pluripotent stem cells (miPSCs). When wild-type (WT) and Nox2-knockout (Nox2−/−) miPSCs were differentiated into ECs (miPSC-ECs), the expression of endothelial markers, arterial endothelial markers, pro-angiogenic cytokines, and Notch pathway components was suppressed in the Nox2−/− cells but increased in both WT and Nox2−/− miPSCs when Nox2 expression was upregulated. Higher levels of Nox2 expression increased Notch signaling and arterial EC differentiation, and this increase was abolished by the inhibition of ROS generation or by the silencing of Notch1 expression. Nox2 deficiency was associated with declines in the survival and angiogenic potency of miPSC-ECs, and capillary and arterial density were lower in the ischemic limbs of mice after treatment with Nox2−/− miPSC-ECs than WT miPSC-EC treatment. Taken together, these observations indicate that Nox2-mediated ROS production promotes arterial EC specification in differentiating miPSCs by activating the Notch signaling pathway and contributes to the angiogenic potency of transplanted miPSC-derived ECs. PMID:27642005

  10. Increased p22phox/Nox4 Expression Is Involved in Remodeling Through Hydrogen Peroxide Signaling in Experimental Persistent Pulmonary Hypertension of the Newborn

    PubMed Central

    Lakshminrusimha, Satyan; Czech, Lyubov; Schumacker, Paul T.; Steinhorn, Robin H.

    2013-01-01

    Abstract Aim: To determine if the NADPH oxidase isoform Nox4 contributes to increased H2O2 generation in persistent pulmonary hypertension of the newborn (PPHN) pulmonary arteries (PA), and to identify downstream signaling targets of Nox4 that contribute to vascular remodeling and vasoconstriction. Results: PPHN was induced in lambs by antenatal ligation of the ductus arteriosus at 128 days gestation. After 9 days, lungs, PA, and PA smooth muscle cells (PASMC) were isolated from control and PPHN lambs. Increased expression of p22phox and Nox4 in PPHN lungs, PA, and PASMC was associated with increased reactive oxygen species in PPHN PA, increased protein thiol oxidation in PPHN PASMC, and a decreased activity of extracellular superoxide dismutase (ecSOD) in the lungs and PASMC. Nox4 small interfering RNA (siRNA) decreased Nox4 expression and thiol oxidation and increased the ecSOD activity in PPHN PASMC. An increased activity of nuclear factor-kappa B (NFκB) and expression of its target gene cyclin D1 were detected in PPHN lungs, PA, and PASMC. Nox4 siRNA and catalase attenuated these increases in PASMC, and catalase decreased cyclin D1 expression in PPHN lungs. Innovation: This study demonstrates for the first time that Nox4 expression is elevated in a lamb model of neonatal pulmonary hypertension. It identifies increased NFκB and cyclin D1 expression and a decreased ecSOD activity as targets of increased Nox4 signaling. Conclusion: PPHN increases p22phox and Nox4 expression and activity resulting in elevated H2O2 levels in PPHN PA. Increased H2O2 induces vasoconstriction via mechanisms involving ecSOD inactivation, and stimulates vascular remodeling via NFκB activation and increased cyclin D1 expression. Approaches that inhibit the pulmonary arterial Nox4 activity may attenuate vasoconstriction and vascular remodeling in PPHN. Antioxid. Redox Signal. 18, 1765–1776. PMID:23244636

  11. NOX1/2 activation in human gingival fibroblasts by Fusobacterium nucleatum facilitates attachment of Porphyromonas gingivalis.

    PubMed

    Ahn, Sun Hee; Song, Ji-Eun; Kim, Suhee; Cho, Sung-Hyun; Lim, Yun Kyong; Kook, Joong-Ki; Kook, Min-Suk; Lee, Tae-Hoon

    2016-08-01

    Periodontal diseases are infectious polymicrobial inflammatory diseases that lead to destruction of the periodontal ligament, gingiva, and alveolar bone. Sequential colonization of a broad range of bacteria, including Fusobacterium nucleatum and Porphyromonas gingivalis, is an important phenomenon in this disease model. F. nucleatum is a facultative anaerobic species thought to be a key mediator of dental plaque maturation due to its extensive coaggregation with other oral bacteria, while P. gingivalis is an obligate anaerobic species that induces gingival inflammation by secreting various virulence factors. The formation of a bacterial complex by these two species is central to the pathogenesis of periodontal disease. Reactive oxygen species (ROS) are produced during bacterial infections and are involved in intracellular signaling. However, the impact of oral bacteria-induced ROS on the ecology of F. nucleatum and P. gingivalis has yet to be clarified. In the present study, we investigated ROS production induced in primary human oral cells by F. nucleatum and P. gingivalis and its effect on the formation of their bacterial complexes and further host cell apoptosis. We found that in primary human gingival fibroblasts (GFs), two NADPH oxidase isoforms, NOX1 and NOX2, were activated in response to F. nucleatum infection but not P. gingivalis infection. Accordingly, increased NADPH oxidase activity and production of superoxide anion were observed in GFs after F. nucleatum infection, but not after P. gingivalis infection. Interestingly, in NOX1, NOX2, or NOX1/NOX2 knockdown cells, the number of P. gingivalis decreased when the cells were coinfected with F. nucleatum. A similar pattern of host cell apoptosis was observed. This implies that F. nucleatum contributes to attachment of P. gingivalis by triggering activation of NADPH oxidase in host cells, which may provide an environment more favorable to strict anaerobic bacteria and have a subsequent effect on apoptosis of

  12. Gaseous modification of MCrAlY coatings

    DOEpatents

    Vance, Steven J.; Goedjen, John G.; Sabol, Stephen M.; Sloan, Kelly M.

    2000-01-01

    The present invention generally describes methods for modifying MCrAlY coatings by using gaseous carburization, gaseous nitriding or gaseous carbonitriding. The modified MCrAlY coatings are useful in thermal barrier coating systems, which may be used in gas turbine engines.

  13. The oxidative molecular regulation mechanism of NOX in children with phenylketonuria.

    PubMed

    He, Ying-Zhong; Gu, Xue-Fan; Lu, Li-Hua; Liang, Li-Li

    2014-11-01

    Phenylketonuria (PKU) is the most frequent inherited disorder of amino acid metabolism. In our previous work, we investigated the role of NADPH oxidase (NOX) in a Pahenu2-BTBR PKU mouse model, and an in vitro cell culture model of PKU. In the current study, we evaluated various oxidative stress parameters, namely total antioxidant capacity (T-AOC), glutathione (GSH) and maleic dialdehyde (MDA) in the plasma of 40 PKU children, for further investigating the oxidative molecular regulation mechanism of NOX in PKU. It was observed that T-AOC and GSH markedly decreased in PKU as compared with the control group (P<0.01), and seemed to correlate negatively with Phe level. However, there was no statistical difference in MDA level among the three groups. And 8-isoprostane in the blood samples of PKU2 groups was slightly higher than control group (P<0.05). Additionally, mRNA levels of subunits of NOX included p47(phox) and p67(phox) significantly increased in PKU group (P<0.01). These results reflected that NOX is the important source of reactive oxygen species and is involved in the oxidative molecular regulation mechanism in PKU, which shows a new perspective toward understanding the biological underpinnings of PKU.

  14. Towards New Constraints on Ozone Production from Lightning NOx via Satellite Measurements of Peroxyacetyl Nitrate (PAN)

    NASA Astrophysics Data System (ADS)

    Payne, V.; Fischer, E. V.; Kulawik, S. S.; Zhu, L.; Worden, J. R.

    2015-12-01

    Quantifying the strength and distribution of the source of nitrogen oxide radicals (NOx) from lightning, and the impact of this source on tropospheric ozone, is critical to understanding the contribution of anthropogenic vs natural sources of ozone as well as feedbacks between climate change and atmospheric chemistry. In the presence of biogenic volatile organic compounds, lightning NOx may be converted to peroxyacetyl nitrate (PAN). PAN formation acts to sequester NOx and decrease ozone formation, thereby playing an important role in determining the oxidation capacity of the troposphere. However, comprehensive in situ measurements of reactive nitrogen species in the upper troposphere are insufficient for the purpose of validation of the representation of the relevant processes in chemical transport models. New satellite measurements of PAN from the Aura Tropospheric Emission Spectrometer (TES) provide an opportunity to place new constraints on the influence of lightning NOx on ozone production. Here we show that TES provides direct observations of enhanced PAN concentrations downwind of convective events over the US in summertime, evaluate the ability of the GEOS-Chem model to reproduce these enhancements and quantify the reduction in ozone formation that would result from the observed PAN. We will also discuss the prospects for PAN retrievals from other nadir-viewing satellite instruments.

  15. Computational investigation of carbon-in-ash levels for a wall-fired boiler after low-NOx combustion modifications

    SciTech Connect

    Davis, K.A.; Eddings, E.G.; Heap, M.P.; Facchiano, A.; Hardman, R.R.

    1998-12-31

    Many coal-fired boilers retrofitted with low NOX firing systems are experiencing significant operational difficulties due primarily to (1) increased carbon in the fly ash or (2) increased water wall wastage. This paper presents the results of a computational investigation of a wall-fired boiler that has recently been retrofitted with low NOx burners and overfire air. The focus of this paper is the effect of the retrofit on unburned carbon/NOx and the potential for applying operational and design modifications to minimize unburned carbon without adversely impacting NOx emissions. Although the magnitude of an increase in unburned carbon after a low NOx retrofit is system and coal dependent, it is often the case that reduction in emissions of nitrogen oxides is accompanied by a corresponding increase in the amount of unburned carbon in fly ash. Since low NOX firing systems increase the residence time of coal/char particles in a fuel rich environment, it might be expected that there is insufficient time under high temperature, oxidizing conditions to ensure complete carbon oxidation in a low NOx firing system. A relatively straight forward consideration of the effect of temperature and oxygen concentration on coal particle pyrolysis/oxidation can be used to provide a qualitative understanding of this effect. However, the complex flow patterns and highly nonlinear physical and chemical phenomena in a boiler make it difficult to predict carbon-in-ash (c-i-a) levels without the use of advanced computational tools. The sensitivity of c-i-a to burnout is pointed out in a figure for a coal with 10% ash. Although c-i-a changes slowly for low burnout, it changes very rapidly at the extent of burnout typical of a boiler. When the extent of burnout drops only slightly, from 99.5 to 99 percent for example, the c-i-a doubles, from 4 to 8%, which in many situations would be unacceptable. The importance of fuel efficiency and ash disposal/recycle emphasizes the need for

  16. Gaseous mediators in resolution of inflammation.

    PubMed

    Wallace, John L; Ianaro, Angela; Flannigan, Kyle L; Cirino, Giuseppe

    2015-05-01

    There are numerous gaseous substances that can act as signaling molecules, but the best characterized of these are nitric oxide, hydrogen sulfide and carbon monoxide. Each has been shown to play important roles in many physiological and pathophysiological processes. This article is focused on the effects of these gasotransmitters in the context of inflammation. There is considerable overlap in the actions of nitric oxide, hydrogen sulfide and carbon monoxide with respect to inflammation, and these mediators appear to act primarily as anti-inflammatory substances, promoting resolution of inflammatory processes. They also have protective and pro-healing effects in some tissues, such as the gastrointestinal tract and lung. Over the past two decades, significant progress has been made in the development of novel anti-inflammatory and cytoprotective drugs that release of one or more of these gaseous mediators.

  17. Effect of gaseous ammonia on nicotine sorption

    SciTech Connect

    Webb, A.M.; Singer, B.C.; Nazaroff, W.W.

    2002-06-01

    Nicotine is a major constituent of environmental tobacco smoke. Sorptive interactions of nicotine with indoor surfaces can substantially alter indoor concentrations. The phenomenon is poorly understood, including whether sorption is fully reversible or partially irreversible. They hypothesize that acid-base chemistry on indoor surfaces might contribute to the apparent irreversibility of nicotine sorption under some circumstances. Specifically, they suggest that nicotine may become protonated on surfaces, markedly reducing its vapor pressure. If so, subsequent exposure of the surface to gaseous ammonia, a common base, could raise the surface pH, causing deprotonation and desorption of nicotine from surfaces. A series of experiments was conducted to explore the effect of ammonia on nicotine sorption to and reemission from surfaces. The results indicate that, under some conditions, exposure to gaseous ammonia can substantially increase the rate of desorption of previously sorbed nicotine from common indoor surface materials.

  18. Cs based photocathodes for gaseous detectors

    SciTech Connect

    Borovick-Romanov, A.; Peskov, V.

    1993-08-01

    We demonstrated that some standard photocathodes SbCs, GaAs(Cs), Au(Cs) can easily be manufactured for use inside gaseous detectors. When filed with clean quenched gases such detectors have a quantum efficiency of a few percent in the visible region of the spectra and can operate at a gain >10{sup 3}. We tried to make these photocathodes more air stable by protecting their surfaces with a thin layer of CsI or liquid TMAE. The most air stable were photocathodes with a CsI protective layer. A wavelengths {le}185 nm such photocathodes have the highest quantum efficiency among all known air stable photocathodes, including CsI. Gaseous detectors with such photocathodes can operate at a gain of 10{sup 5}. Results of first tests of doped CsI photocathode are also presented. Possible fields of application of new photocathodes are discussed.

  19. Gaseous fuel reactor systems for aerospace applications

    NASA Technical Reports Server (NTRS)

    Thom, K.; Schwenk, F. C.

    1977-01-01

    Research on the gaseous fuel nuclear rocket concept continues under the programs of the U.S. National Aeronautics and Space Administration (NASA) Office for Aeronautics and Space Technology and now includes work related to power applications in space and on earth. In a cavity reactor test series, initial experiments confirmed the low critical mass determined from reactor physics calculations. Recent work with flowing UF6 fuel indicates stable operation at increased power levels. Preliminary design and experimental verification of test hardware for high-temperature experiments have been accomplished. Research on energy extraction from fissioning gases has resulted in lasers energized by fission fragments. Combined experimental results and studies indicate that gaseous-fuel reactor systems have significant potential for providing nuclear fission power in space and on earth.

  20. Quantitative Thermochemical Measurements in High-Pressure Gaseous Combustion

    NASA Technical Reports Server (NTRS)

    Kojima, Jun J.; Fischer, David G.

    2012-01-01

    We present our strategic experiment and thermochemical analyses on combustion flow using a subframe burst gating (SBG) Raman spectroscopy. This unconventional laser diagnostic technique has promising ability to enhance accuracy of the quantitative scalar measurements in a point-wise single-shot fashion. In the presentation, we briefly describe an experimental methodology that generates transferable calibration standard for the routine implementation of the diagnostics in hydrocarbon flames. The diagnostic technology was applied to simultaneous measurements of temperature and chemical species in a swirl-stabilized turbulent flame with gaseous methane fuel at elevated pressure (17 atm). Statistical analyses of the space-/time-resolved thermochemical data provide insights into the nature of the mixing process and it impact on the subsequent combustion process in the model combustor.

  1. Diffusion method of seperating gaseous mixtures

    DOEpatents

    Pontius, Rex B.

    1976-01-01

    A method of effecting a relatively large change in the relative concentrations of the components of a gaseous mixture by diffusion which comprises separating the mixture into heavier and lighter portions according to major fraction mass recycle procedure, further separating the heavier portions into still heavier subportions according to a major fraction mass recycle procedure, and further separating the lighter portions into still lighter subportions according to a major fraction equilibrium recycle procedure.

  2. Dry-Enzyme Test For Gaseous Chemicals

    NASA Technical Reports Server (NTRS)

    Barzana, Eduardo; Karel, Marcus; Klibanov, Alexander

    1990-01-01

    Simple, dry-chemical test detects ethanol in human breath. Method of test also adapted to detection of such toxic chemicals as formaldehyde in airstreams. Used qualitatively to detect chemical compounds above present level; for example, ethanol above legal level for driving. Also used to indicate quantitatively concentrations of compounds. Involves dry enzyme and color indicator. Adapted to detect any gaseous compound transformed by enzymes to produce change evident to human eye or to instrument.

  3. Uranium enrichment export control guide: Gaseous diffusion

    SciTech Connect

    Not Available

    1989-09-01

    This document was prepared to serve as a guide for export control officials in their interpretation, understanding, and implementation of export laws that relate to the Zangger International Trigger List for gaseous diffusion uranium enrichment process components, equipment, and materials. Particular emphasis is focused on items that are especially designed or prepared since export controls are required for these by States that are party to the International Nuclear Nonproliferation Treaty.

  4. Gaseous reference standards of formaldehyde from trioxane.

    PubMed

    Brewer, Paul J; di Meane, Elena Amico; Vargha, Gergely M; Brown, Richard J C; Milton, Martin J T

    2013-04-15

    We have developed a dynamic reference standard of gaseous formaldehyde based on diffusion of the sublimate of trioxane and thermal conversion to formaldehyde in the gas phase. We have also produced a gravimetric standard for formaldehyde in a nitrogen matrix, also by thermal conversion of the sublimate of trioxane. Analysis of the gravimetric standard with respect to the dynamic standard has confirmed the comparability of the static and dynamic gravimetric values.

  5. Trace organic impurities in gaseous helium

    NASA Technical Reports Server (NTRS)

    Schehl, T. A.

    1973-01-01

    A program to determine trace organic impurities present in helium has been initiated. The impurities were concentrated in a cryogenic trap to permit detection and identification by a gas chromatographic-mass spectrometric technique. Gaseous helium (GHe) exhibited 63 GC flame ionization response peaks. Relative GC peak heights and identifications of 25 major impurities by their mass spectra are given. As an aid to further investigation, identities are proposed for 16 other components, and their mass spectra are given.

  6. Correlation and prediction of gaseous diffusion coefficients.

    NASA Technical Reports Server (NTRS)

    Marrero, T. R.; Mason, E. A.

    1973-01-01

    A new correlation method for binary gaseous diffusion coefficients from very low temperatures to 10,000 K is proposed based on an extended principle of corresponding states, and having greater range and accuracy than previous correlations. There are two correlation parameters that are related to other physical quantities and that are predictable in the absence of diffusion measurements. Quantum effects and composition dependence are included, but high-pressure effects are not. The results are directly applicable to multicomponent mixtures.

  7. Selective remote diagnostics of gaseous hydrocarbon flames

    NASA Astrophysics Data System (ADS)

    Antsygin, Valery D.; Borzov, Sergei M.; Kozik, Victor I.; Potaturkin, Oleg I.; Shushkov, Nikolai N.; Vaskov, S. T.

    1997-05-01

    An optoelectronic remote method of gaseous flame parameters determination is suggested. It is based on the principles of passive optical spectroscopy with the use of a receiving radiation of tongues followed by electronic digital data processing. The radiation is registered in green-blue range of spectrum by multielement semiconductor photodetector with a predominant use of one spatial coordinate and optical integration along the other coordinate. The digital data processing is performed by means of local and pointwise image processing operators.

  8. NOx emissions from a Central California dairy

    NASA Astrophysics Data System (ADS)

    Hasson, Alam S.; Ogunjemiyo, Segun O.; Trabue, Steven; Ashkan, Shawn; Scoggin, Kenwood; Steele, Julie; Olea, Catalina; Middala, Srikar; Vu, Kennedy; Scruggs, Austen; Addala, Laxmi R.; Nana, Lucien

    2013-05-01

    Concentrations of NOx (NO + NO2) were monitored downwind from a Central California dairy facility during 2011 and 2012. NOx concentrations at the dairy were significantly higher than the background levels during August 2011 primarily due to the presence of elevated NO, but were indistinguishable from background concentrations during January and April 2012. A Gaussian plume model (AERMOD) and a Lagrangian back trajectory model (Wind Trax) were used to estimate the flux of NO from the dairy during August 2011 with the assumption that emissions were primarily from animal feed. NO emissions from silage were also directly measured from feed to provide additional insight into the sources. Isolation flux chamber measurements imply an NO flux from the feed of about 1.3 × 10-3 g m-2 h-1, but these relatively low fluxes are inconsistent with the elevated NO concentrations observed during August 2011. This implies that either the flux chamber method grossly underestimates the true NO emissions from feed, or that most of the ambient NO measured at the dairy is from other sources. Emissions from farm machinery may account for the NO concentrations observed. Animal feed thus appears to be a small contributor to NOx emissions within Central California.

  9. Determination of intermediates and mechanism for soot combustion with NOx/O₂ on potassium-supported Mg-Al hydrotalcite mixed oxides by in situ FTIR.

    PubMed

    Zhang, Zhaoliang; Zhang, Yexin; Su, Qingyun; Wang, Zhongpeng; Li, Qian; Gao, Xiyan

    2010-11-01

    The soot combustion with NO(x) and/or O(2) on potassium-supported Mg-Al hydrotalcite mixed oxides under tight contact condition was studied using temperature-programmed oxidation (TPO), isothermal reaction and in situ FTIR techniques. The presence of NO(x) in O(2) favors the soot combustion at lower temperatures (<300 °C). However, a little suppression was observed at higher temperatures (>300 °C), which was accompanied by a substantial NO(x) reduction. The ketene (C═C═O) and isocyanate (NCO(-)) species were determined as the reaction intermediates. In NO(x) + O(2), NO(2) directly interacts with the free carbon sites (C═C*) through two parallel reactions: (1) NO(2) + C═C* → C═C═O + NO; (2) NO(2) + C═C* → NCO(-) + CO(2). The two reactions can proceed easily, which accounts for the promotion effect of NO(x) on soot combustion at lower temperatures. The further oxidation of NCO(-) by NO(2) or O(2) is responsible for the simultaneous reduction of NO(x). However, the reactions between NO(2) and C═C* are limited by the amount of free carbon sites, which can be provided by the oxidation of soot by O(2) at higher temperatures. The interaction of NO(x) and catalyst results in the formation of nitrates and nitrites, which poisoned the active K sites.

  10. Method for reacting nongaseous material with a gaseous reactant

    DOEpatents

    Lumpkin, Robert E.; Duraiswamy, Kandaswamy

    1979-03-27

    This invention relates to a new and novel method and apparatus for reacting nongaseous material with a gaseous reactant comprising introducing a first stream containing a nongaseous material into a reaction zone; simultaneously introducing a second stream containing a gaseous reactant into the reaction zone such that the gaseous reactant immediately contacts and reacts with the first stream thereby producing a gaseous product; forming a spiralling vortex within the reaction zone to cause substantial separation of gases, including the gaseous product, from the nongaseous material; forming and removing a third stream from the reaction zone containing the gaseous product which is substantially free of the nongaseous material before a major portion of the gaseous product can react with the nongaseous material; and forming and removing a fourth stream containing the nongaseous material from the reaction zone.

  11. NOx Reduction with Natural Gas for Lean Large-Bore Engine Applications Using Lean NOx Trap Aftertreatment

    SciTech Connect

    Parks, JE

    2005-02-11

    Large-bore natural gas engines are used for distributed energy and gas compression since natural gas fuel offers a convenient and reliable fuel source via the natural gas pipeline and distribution infrastructure. Lean engines enable better fuel efficiency and lower operating costs; however, NOx emissions from lean engines are difficult to control. Technologies that reduce NOx in lean exhaust are desired to enable broader use of efficient lean engines. Lean NOx trap catalysts have demonstrated greater than 90% NOx reduction in lean exhaust from engines operating with gasoline, diesel, and natural gas fuels. In addition to the clean nature of the technology, lean NOx traps reduce NOx with the fuel source of the engine thereby eliminating the requirement for storage and handling of secondary fuels or reducing agents. A study of lean NOx trap catalysts for lean natural gas engines is presented here. Testing was performed on a Cummins C8.3G (CG-280) engine on a motor dynamometer. Lean NOx trap catalysts were tested for NOx reduction performance under various engine operating conditions, and the utilization of natural gas as the reductant fuel source was characterized. Engine test results show that temperature greatly affects the catalytic processes involved, specifically methane oxidation and NOx storage on the lean NOx trap. Additional studies on a bench flow reactor demonstrate the effect of precious metal loading (a primary cost factor) on lean NOx trap performance at different temperatures. Results and issues related to the potential of the lean NOx trap technology for large-bore engine applications will be discussed.

  12. 40 CFR 97.160 - Submission of CAIR NOX allowance transfers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Submission of CAIR NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Allowance Transfers § 97.160 Submission of CAIR NOX allowance transfers. A CAIR authorized...

  13. 40 CFR 97.10 - Authorization and responsibilities of NOX authorized account representative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... NOX authorized account representative. 97.10 Section 97.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized Account Representative for NOX Budget Sources §...

  14. 40 CFR 97.423 - Recordation of TR NOX Annual allowance transfers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Recordation of TR NOX Annual allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS TR NOX Annual Trading Program § 97.423 Recordation of TR NOX Annual allowance transfers. (a) Within 5 business...

  15. 40 CFR 97.160 - Submission of CAIR NOX allowance transfers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Submission of CAIR NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Allowance Transfers § 97.160 Submission of CAIR NOX allowance transfers. A CAIR authorized...

  16. 40 CFR 97.85 - NOX Budget opt-in permit contents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false NOX Budget opt-in permit contents. 97... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins § 97.85 NOX Budget opt-in permit contents. (a) Each NOX Budget opt-in permit will contain all...

  17. 40 CFR 96.41 - Timing requirements for NOX allowance allocations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Timing requirements for NOX allowance... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Allocations § 96.41 Timing requirements for NOX allowance allocations. (a)...

  18. 40 CFR 96.85 - NOX Budget opt-in permit contents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Budget opt-in permit contents. 96... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.85 NOX Budget opt-in permit contents. (a) Each NOX Budget opt-in...

  19. 40 CFR 97.20 - General NOX Budget Trading Program permit requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false General NOX Budget Trading Program... (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.20 General NOX Budget Trading Program permit requirements. (a) For each NOX Budget...

  20. 40 CFR 97.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Allowance Tracking System § 97.154 Compliance with CAIR NOX emissions limitation. (a) Allowance...

  1. 40 CFR 96.186 - Withdrawal from CAIR NOX Annual Trading Program.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Withdrawal from CAIR NOX Annual... (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Opt-in Units § 96.186 Withdrawal from CAIR NOX Annual...

  2. 40 CFR 97.21 - Submission of NOX Budget permit applications.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Submission of NOX Budget permit... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.21 Submission of NOX Budget permit applications. (a) Duty to apply. The NOX authorized...

  3. 40 CFR 97.186 - Withdrawal from CAIR NOX Annual Trading Program.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Withdrawal from CAIR NOX Annual... (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Opt-In Units § 97.186 Withdrawal from CAIR NOX Annual Trading Program. Except as...

  4. 40 CFR 97.425 - Compliance with TR NOX Annual assurance provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Compliance with TR NOX Annual... (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS TR NOX Annual Trading Program § 97.425 Compliance with TR NOX Annual assurance provisions....

  5. 40 CFR 97.422 - Submission of TR NOX Annual allowance transfers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Submission of TR NOX Annual allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS TR NOX Annual Trading Program § 97.422 Submission of TR NOX Annual allowance transfers. (a) An authorized...

  6. 40 CFR 97.153 - Recordation of CAIR NOX allowance allocations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Recordation of CAIR NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Allowance Tracking System § 97.153 Recordation of CAIR NOX allowance allocations. (a) By September 30,...

  7. 40 CFR 96.24 - Effective date of initial NOX Budget permit.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Effective date of initial NOX Budget... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.24 Effective date of initial NOX Budget permit. The initial NOX Budget...

  8. 40 CFR 96.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Allowance Tracking System § 96.154 Compliance with CAIR NOX emissions...

  9. 40 CFR 96.160 - Submission of CAIR NOX allowance transfers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Submission of CAIR NOX allowance... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Allowance Transfers § 96.160 Submission of CAIR NOX allowance transfers. A...

  10. 40 CFR 96.14 - Objections concerning the NOX authorized account representative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Objections concerning the NOX... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Authorized Account Representative for NOX Budget Sources §...

  11. 40 CFR 97.423 - Recordation of TR NOX Annual allowance transfers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Recordation of TR NOX Annual allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS TR NOX Annual Trading Program § 97.423 Recordation of TR NOX Annual allowance transfers. (a) Within 5 business...

  12. 40 CFR 96.24 - Effective date of initial NOX Budget permit.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Effective date of initial NOX Budget... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO 2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.24 Effective date of initial NOX Budget permit. The initial NOX Budget...

  13. 40 CFR 97.160 - Submission of CAIR NOX allowance transfers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Submission of CAIR NOX allowance... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Allowance Transfers § 97.160 Submission of CAIR NOX allowance transfers. A CAIR authorized...

  14. 40 CFR 97.141 - Timing requirements for CAIR NOX allowance allocations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Timing requirements for CAIR NOX... (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Allowance Allocations § 97.141 Timing requirements for CAIR NOX allowance allocations. (a)...

  15. 40 CFR 97.14 - Objections concerning NOX authorized account representative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Objections concerning NOX authorized... (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized Account Representative for NOX Budget Sources § 97.14 Objections concerning...

  16. 40 CFR 96.153 - Recordation of CAIR NOX allowance allocations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Recordation of CAIR NOX allowance... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Allowance Tracking System § 96.153 Recordation of CAIR NOX allowance...

  17. 40 CFR 96.10 - Authorization and responsibilities of the NOX authorized account representative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the NOX authorized account representative. 96.10 Section 96.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Authorized Account Representative for NOX...

  18. 40 CFR 97.20 - General NOX Budget Trading Program permit requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false General NOX Budget Trading Program... (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Permits § 97.20 General NOX Budget Trading Program permit requirements. (a) For each NOX Budget...

  19. 40 CFR 97.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Ozone Season Allowance Tracking System § 97.354 Compliance with CAIR NOX emissions limitation....

  20. 40 CFR 96.14 - Objections concerning the NOX authorized account representative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Objections concerning the NOX... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Authorized Account Representative for NOX Budget Sources §...