Rozprawy doktorskie: „Oxide - Nitrogen”

1

Li, Sonny X. "Nitrogen doped zinc oxide thin film". Berkeley, Calif. : Oak Ridge, Tenn. : Lawrence Berkeley National Laboratory ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2003. http://www.osti.gov/servlets/purl/821916-VLVAK9/native/.

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Thesis (M.S.); Submitted to the University of California, Berkeley, 210 Hearst Mining Memorial Bldg., Berkeley, CA 94720 (US); 15 Dec 2003.
Published through the Information Bridge: DOE Scientific and Technical Information. "LBNL--54116" Li, Sonny X. USDOE Director. Office of Science. Basic Energy Sciences (US) 12/15/2003. Report is also available in paper and microfiche from NTIS.

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2

Jewmaidang, Jirasak. "Homogeneous sulfur tri-oxide formation in gas reburning for nitrogen oxides control". Ohio : Ohio University, 1999. http://www.ohiolink.edu/etd/view.cgi?ohiou1175801641.

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3

Skinn, Brian Thomas. "Nitrogen oxide delivery systems for biological media". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/70107.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2012.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 345-363).
Elevated levels of nitric oxide (NO) in vivo are associated with a variety of cellular modifications thought to be mutagenic or carcinogenic. These processes are likely mediated by reactive nitrogen species (RNS) such as nitrogen dioxide (NO2) and peroxynitrite formed from the respective reactions of NO with oxygen and superoxide anion. Controlled delivery of these RNS at levels expected to occur in vivo is desirable in studying these processes and their role in the etiology of various diseases. Two delivery systems were developed that provide novel capabilities for steady, quantitative exposure of biological targets to RNS over periods from hours to days. Quantitative models are presented that accurately describe the behavior of both systems. The first system achieves NO concentrations of 0.6-3.0 [mu]M in a stirred, liquid-filled vessel by diffusion from a gas stream through a porous poly(tetrafluoroethylene) membrane. Oxygen, consumed by reaction with NO or by other processes, is supplied by diffusion from a separate gas stream through a loop of poly(dimethylsiloxane) tubing. The adventitious chemistry observed in a prior device for NO delivery [Wang C. Ann Biomed Eng (2003) 31:65-79] is eliminated in the present design, as evidenced by the close match to model predictions of the accumulation rate of nitrite, the stable end product of NO oxidation. The second system delivers NO2 by direct contacting of a stirred liquid with an NO2- containing gas mixture. Accumulation rates of products in the presence and absence of the NO2-reactive substrate 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) matched model predictions within 15% for all conditions studied. The predicted steady NO2 concentration in the liquid is on the order of 400 pM, similar to what is expected to be present in extracellular fluids in the presence of 1 [mu]M NO. This system appears to be the first reported with the capability for sustained, quantitative NO2 delivery to suspended cell cultures. Results from initial efforts to test a novel mixing model for bolus delivery of peroxynitrite to agitated solutions imply that the proposed model might accurately describe mixing in bolus delivery experiments with agitation by vortex mixing, but further work is required to validate the model.
by Brian Thomas Skinn.
Ph.D.

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4

Mereb, Jamal Bocher. "Nitrogen oxide abatement by distributed fuel addition". Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185383.

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Reburning is examined as a means of NOₓ destruction in a 17 kW down-fired pulverized coal combustor. In reburning, a secondary fuel is introduced downstream of the primary flame to produce a reducing zone, favorable to NO destruction, and air is introduced further downstream to complete the combustion. Emphasis is on natural gas reburning and a bituminous coal primary flame. A parametric examination of reburning employing a statistical experimental design, is conducted, complemented by detailed experiments. Mechanisms governing the inter-conversion of nitrogenous species in the fuel rich reburn zone are explored. The effect of reburning on N₂O emissions, the effect of primary flame mode (premixed and diffusion) and the effect of distributing the reburning fuel, are also investigated. The parametric study allowed the effects of significant reburning variables to be identified and examined, but these effects could not be quantified. Detailed experiments identified optimum reburn zone stoichiometry between 0.8 and 0.9, depending on mixing in the reburn zone. Overall NO reductions, as high as 80%, were possible and depended mainly on reburn zone variables, namely, temperature, residence time and stoichiometry. Exhaust N₂O emissions increased after air addition in the final stage of reburning, but were less than 10 ppm. Lower reductions in NO emissions were obtained when the primary flame was of the diffusion type, rather than of the premixed type, but final NO emissions below 250 ppm (dry, 0% O₂) were still possible. Reburning fuel introduction in multiple streams did not enhance NO destruction, relative to single stream injections. Within the reburn zone, reburning mechanisms occurred in two regimes. One regime was in the vicinity of the reburning fuel flame and was distinguished by fast reactions between NO and hydrocarbons that were limited by mixing. The other regime covered the remainder of the reburn zone and was distinguished by slower reactions, without mixing complications. For the latter regime, a simplified model based on detailed gas phase chemical kinetic mechanisms and known rate coefficients was able to predict temporal profiles of NO, HCN and NH₃. Reactions involving hydrocarbons played important roles in both regimes and N₂ fixation by hydrocarbons limited reburning effectiveness at low primary NO values. Appropriate corrections for mixing effects in early time scales of the reburn zone allowed the prediction of nitrogenous species profiles from primary NO values, as well as overall reburning effectiveness.

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5

Estupiñán, Edgar G. "Laboratory studies of potentially important atmospheric processes involving oxides of nitrogen". Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/25877.

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6

Holmgreen, Erik Michael. "Nitrogen dioxide reduction with methane over palladium-based sulfated zirconia catalysts a componant [i.e. component] of a lean exhaust aftertreatement system /". Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1155739813.

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7

Wood, Simon Andrew. "Corrosion studies in liquid nitrogen oxides". Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262774.

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8

Dunfield, Peter F. "Methane, nitrogen monoxide, and nitrous oxide fluxes in an organic soil". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0020/NQ36972.pdf.

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9

Gold, Scott Alan. "Nitrogen incorporation in thin silicon oxide films for passivation of silicon solar cell surfaces". Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/11101.

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10

Hannon, Andrew Michael. "Exploring the Reactivity and Decomposition of Ruthenium Nitrosyl Complexes for the Production of Nitrogen Oxides". Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/243113.

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Nitric oxide (NO) has been shown to both suppress and promote tumor growth, depending in part on concentration. Exogenous delivery of NO may lead to tumor suppression. Recent studies have proposed ruthenium nitrosyl complexes as catalytic donors of NO in reductive environments. Catalytic donation can provide a long-term, elevated NO flux compared to single use donors. Site-specific delivery is desirable to reduce systemic side effects, such as lowering of blood pressure. Three new ruthenium nitrosyl complexes were synthesized to impart site-specificity through amide coupling to polymers, silica nanoparticles, iron oxide nanoparticles and antibodies. The catalytic activity of new and existing compounds was then assessed. However, upon one-electron reduction of ruthenium nitrosyl complexes, insignificant amounts of NO were detected, suggesting an alternative mechanism than that proposed in prior reports. The mechanism of [Ru(EDTA)NO]²⁻ decay was more thoroughly analyzed. Spectrophotometric decay of [Ru(EDTA)NO]²⁻ indicates that one or multiple nitrogen oxide species are released. Previous studies have suggested a disproportionation mechanism leading to the generation of more highly reduced species such as N₂ and NH₄⁺. Experiments were designed to analyze possible decomposition products such as [Ru(EDTA)NO]⁻ and [Ru(EDTA)H₂O]²⁻. A disproportionation mechanism was determined likely. Decomposition of [Ru(EDTA)NO]²⁻ was also observable following reductive nitrosylation of [Ru(EDTA)H₂O]⁻ in the presence of HNO. The decomposition product, [Ru(EDTA)H₂O]²⁻, was observed through the binding of pyrazine (pz) or dipyridine (bipy) and formation of [Ru(EDTA)pz]²⁻ or [Ru(EDTA)bipy]³⁻. Formation of [Ru(EDTA)bipy]³⁻ or [Ru(EDTA)pz]²⁻ via reductive nitrosylation of [Ru(EDTA)H₂O]⁻ also provides an indirect method of HNO detection that is selective from NO.

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11

West, Pamela Jayne. "Electrochemistry and corrosion studies in nitrogen oxide liquid media". Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357065.

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12

Bharadwaj, Gaurav. "Synthesis and Pharmacological Evaluation of Nitrogen Oxide Releasing Prodrugs". Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/301748.

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The main goals of this research were to synthesize nitrogen oxide releasing diazeniumdiolates and their prodrugs and to evaluate their pharmacological effects. The different projects and their results are described below. i. Comparison of HNO and NO donating properties of cyclic amine diazeniumdiolates Diazeniumdiolates are an attractive class of donor compounds as they can be tuned to release NO or both NO and HNO depending upon the amine backbone. Isopropylamine (IPA/NO) and cyclohexylamine (CHA/NO) diazeniumdiolates are currently the only examples of primary amine based diazeniumdiolates. A series of structurally related cyclic amine based diazeniumdiolates were synthesized and characterized. An acetoxymethyl derivative was also synthesized to facilitate cellular uptake and to achieve higher HNO levels in cells. ii. Nitrogen oxide releasing diazeiumdiolate based adducts of N-des-methyl-tamoxifen Nitrogen oxide (NO/HNO) donating diazeniumdiolate adducts of N-desmethyltamoxifen (a key metabolite of the breast cancer drug tamoxifen) were synthesized. DEA/NO-AcOM, an NO donor was also synthesized to monitor the effect of NO on breast cancer cell survival. Derivatives of N-desmethyltamoxifen were found to be effective towards estrogen receptor positive (ER+) cells only. DEA/NO-AcOM was found to be cytotoxic towards estrogen-dependent and independent cell lines, in combination with tamoxifen, or by itself. iii. Synthesis and characterization of nitrogen oxide adducts with non-steroidal anti-inflammatory drugs (NSAIDs) Our group has shown HNO releasing diazeniumdiolate derivatized aspirin to be comparably effective in preventing gastric ulceration to NO-releasing diazeniumdiolate based aspirin analogues. Series of such NSAID adducts were further extended by synthesizing such derivatives of indomethacin and niflumic acid. NO/HNO releasing analogues of aspirin and indomethacin were cytotoxic towards two different breast cancer cell lines, irrespective of estrogen dependence.iv. Chlorambucil analogue of PABA/NOChlorambucil, an alkylating agent is used in leukemia treatment. Tumor cells resistant to alkylating agents often have increased glutathione levels and increased activity of glutathione-S-transferase (GST). PABA/NO is an NO donor with a promising anticancer profile. The chlorambucil analogue of PABA/NO was synthesized to utilize GST for releasing NO and to potentially overcome cellular resistance.

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13

Ogden, Gregory E. "Pulverized coal combustion: Flame attachment and nitrogen oxide emissions". Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/289822.

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To fully utilize coal as a long-term energy source, pollution prevention technologies must be developed to mitigate the negative environmental and health impacts of coal combustion. NOₓ emissions are of particular concern due to their role in forming ground-level ozone, photochemical smog, fine particulates and acid rain. A systematic evaluation of near-flame aerodynamics was conducted to determine how burner operating parameters and oxygen partial pressure influence flame attachment and coal ignition, two properties essential for proper low NOₓ burner operation. A laboratory scale (17kW) 2m tall, 0.5m diameter electrically heated furnace and axial burner with adjustable secondary combustion air annuli and primary fuel jets were used in the study. Transport air oxygen partial pressure (PO₂), coal particle size distribution, primary and secondary jet velocity, and wall temperature were varied independently to determine the effect of each variable on flame attachment and NOₓ. NOₓ emissions from the furnace were similar to those from full-scale tangentially-fired boilers. The tendency for flame attachment increased with velocity ratio (Θ), wall temperature, PO₂, and coal fines. Θ's greater than 1 were required for stable combustion. Increasing Θ reduced flame standoff distances and NOₓ for always-detached flames. NOₓ increased with Θ for always-attached flames. Increasing PO₂ reduced NOₓ by up to 50% by promoting flame attachment. However both oxygen enrichment and increasing fines had little impact on NOₓ for always-attached and always-detached flames. Wall temperature and excess air in leakage were the dominant variables affecting NOₓ. Furnace exhaust oxygen levels increased when operating under a slight vacuum with corresponding increases in NOₓ. Emissions for detached flames increased with wall temperature 3 times faster than attached flames. Emissions data obtained from the furnace under slight positive furnace pressure increased linearly with wall temperature. A novel dual flame was produced at high Θ and reduced PO₂ consisting of one flame attached to the burner and one stabilized 18" below the burner. This configuration is similar to staged combustion but without separate over-fire air. Emissions from the dual flame were significantly below those observed from conventional Type-O attached and detached flames.

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14

Wirth, Douglas A. "An experimental investigation of the effect of temporal equivalence ratio fluctuations on NOx̳ emissions in premixed flames /". This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-144729/.

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Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993.
On t.p. "x̳" is subscript. Vita. Abstract. Includes bibliographical references (leaves 179-185). Also available via the Internet.

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15

Paciotti, Robert Neil. "AN EVALUATION OF NITROGEN OXIDE EMISSION FROM A LIGHT-DUTY HYBRID-ELECTRIC VEHICLE TO MEET U.S.E.P.A. REQUIREMENTS USING A DIESEL ENGINE". University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1185480463.

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16

Gormley, Craig Houston. "Modelling coal fired power station NOâ†X emissions". Thesis, Queen's University Belfast, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343026.

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17

Yang, Jiun-Chan. "Nanoporous zeolite and solid-state electrochemical devices for nitrogen-oxide sensing". Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1167408350.

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18

Dijkhhuizen, Roelf Soene. "The antimicrobial activity of nitric oxide and related nitrogen intermediates". Thesis, University of Aberdeen, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287697.

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Endogenous production of nitrate in patients with infective gastroenteritis is increased manifold, and this increase originates from endogenous production of nitric oxide via the enzymatic L-arginine-NO pathway. Endogenous nitrate production seems to be a specific feature of infective gastroenteritis; no significant increase is observed in non-infective diarrhoeal conditions, and the production during other infective conditions such as septicaemia is comparatively modest. Twenty four hours urinary nitrate excretion after a period of minimal oral nitrate intake is the golden standard for measuring endogenous nitrate production, but is difficult to implement and prone to sampling errors. The urinary nitrate/creatinine ratio appears a satisfactory alternative provided that a standardised collection procedure is carried out. The urinary ratio reveals differences in endogenous nitrate production that remain undisclosed with serum nitrate measurements. Addition of nitrite achieves kill of micro-organisms where acid alone allows growth to continue. The synergism in antimicrobial action of acid and nitrite is evident against common gut pathogens such as the Enterobacteriaceae, including E. coli 0157, but also against the stomach pathogen H pylori, normally very resistant to acid alone. The antibacterial action of acidified nitrite becomes apparent at physiological concentrations of acid and nitrite after exposure times that are within the passage time of a food bolus through the stomach. Acidified nitrite also has an antifungal effect against Candida albicans, however at concentrations of acid and nitrite not normally found in the human upper gastro-intestinal tract. The antimicrobial activity of acidified nitrite is enhanced by thiocyanate, also present in gastric juices. Ascorbic acid provides protection against the antibacterial action of acidified nitrite, suggesting that NO is not the antibacterial agent. Acidification of salivary nitrite in the stomach will increase host defence against ingested pathogens. Generation of salivary nitrite increases greatly after nitrate ingestion, suggesting that ingestion of foods rich in nitrate may protect against infective gastroenteritis.

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19

Houmes, Joel David. "New routes to nitride materials : oxide precursors and nitrogen plasmas". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/41411.

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Pitukmanorom, Pemakorn 1976. "Nanocomposites for nitrogen oxide emissions control in lean-burn engines". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28848.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2004.
Includes bibliographical references.
(cont.) reducing agent than propane in the SCR of NO. Pt-Rh/CuO/A1₂O₃ nanocomposites capable of adsorbing SO₂ in oxygen-rich environment as metal sulfates and releasing SO₂ in reducing atmosphere were synthesized with sequential precipitation technique. These CuO-based sorbents possessed excellent SO₂ adsorption capacity and superior regenerability by CO compared to those produced by the impregnation method due to higher surface area and dispersion of Cu species. A gram of sorbent with 30 wt% Cu could adsorb over 50 mg of SO2 before SO₂ breakthrough was observed. The rate of SO₂ desorption from the CuO/A1₂O₃ sorbents could be enhanced through the incorporation of noble metals. With the use of 0.1 wt% Pt, the CuO/A1₂O₃ sorbent with 30 wt% Cu could be regenerated twice as quickly. Also, on average only 8 ppm of SO₂ were detected downstream of this sorbent over each adsorption cycle at 400⁰C. The excellent sorbent regeneration was attributed to better CO adsorption and lower sulfate decomposition temperature as a result of Pt addition. The nature of sulfur deactivation of these sorbents was highly dependent on the composition of noble metals used. By employing both Rh and Pt, sorbent regeneration rate and stability could be optimized. Rh/CuO-MgO/A1₂O₃ nanocomposites capable of adsorbing NOx and SO₂ in oxygen-rich environment and releasing N₂ and SO₂ in reducing atmosphere were successfully prepared by sequential precipitation ...
Over the past few years, increase in environmental concern has led to a demand for more effective pollution control strategies that would satisfy the new EPA standards regarding automotive emissions of nitrogen oxides (NOx). In particular, the removal of NOx from lean-burn and diesel engines operating under an oxygen-rich atmosphere presents a significant challenge as conventional three-way catalysts are ineffective in this environment. Moreover, the presence of water vapor and sulfur oxides (SOx) in the exhaust stream both inhibits catalyst activity and results in long-term catalyst instability. Thus, it is necessary to develop novel technologies for the removal of NOx from the exhaust of lean-bum engines. This thesis examined three metal oxide nanocomposite systems to serve as (i) catalysts for the selective catalytic reduction (SCR) of NOx by propene, (ii) sorbents for SO₂ storage, and (iii) catalysts for NOx storage-reduction (NSR). In₂O₃-Ga₂O₃/A1₂O₃ nanocomposite catalysts have been synthesized using the sequential precipitation technique. These alumina-based catalysts exhibited superior NO reduction activity to those produced by the impregnation and sol-gel methods due to their higher surface area and dispersion of active components. In fact, an excellent N2 yield of 80% was achieved at 450⁰C over the In₂O₃-Ga₂O₃/A1₂O₃ nanocomposite with 2 wt% In and 8 wt% Ga. The high catalytic activity was attributed to better propene activation by In and improved NOx adsorption on the high surface area Ga₂O₃/A1₂O₃. The In₂O₃-Ga₂O₃/A1₂O₃ nanocomposite remained active even in the presence of SO2. The NO reduction activity of this catalyst system depended on the hydrocarbons that were used as the reducing agents. Propene was found to be a more effective
by Pemakorn Pitukmanorom.
Ph.D.

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21

Basudhar, Debashree. "NITROGEN OXIDE RELEASING PRODRUGS AS ANTIINFLAMMATORY, ANTICANCER AND CARDIOPROTECTIVE AGENTS". Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/145745.

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This dissertation focuses on chemical and biological evaluation of diazeniumdiolate based nitrogen oxide releasing prodrugs. Three projects are described. i. Synthesis and biological evaluation of a series of new nitroxyl (HNO) releasing non-steroidal antiinflammatory drugs (NSAIDs) and comparison to related nitric oxide (NO) releasing NSAIDs A series of HNO releasing isopropylamine-based diazeniumdiolate adducts of NSAIDs and the NO releasing diethylamine diazeniumdiolate counterpart were synthesized. The aspirin derivatives were evaluated for antiinflammatory, cardioprotective and anticancer effects. Both prodrugs demonstrated similar antiinflammatory properties to aspirin but significantly lower gastrointestinal ulceration, which is a common side effect of aspirin. The HNO adduct also improved cardiac contractility. The chemotherapeutic potential of the prodrugs was assessed in vitro and in vivo. Both the prodrugs inhibited growth of cultured carcinoma cells without inducing cytotoxicity towards non-tumorogenic cell lines. The higher cytotoxicity of the HNO adduct was in part due to increased production of reactive nitrogen and oxygen species leading to oxidative damage to DNA, inhibition of glyceraldehydes-3-phosphate dehydrogenase and upregulation of signaling pathways leading to caspase-3 mediated induction of apoptosis. The NO adduct is a promising candidate for reduction of metastasis by increasing E-cadherin levels, which influences cellular adhesion. Both derivatives showed significantly reduced angiogenesis in cultured cells and tumor volume in nude mice. ii. Synthesis and characterization of primary amine based cyclic amine diazeniumdiolates and comparison to their acetoxy methyl ester derivatives. A series of HNO releasing cyclic amine diazeniumdiolates were synthesized to expand upon the few examples of primary amine diazeniumdiolates. An ester derivative of cyclopentylamine NONOate was also synthesized, to increase decomposition half-life and to improve HNO production and better cellular uptake. This modification increased its cytotoxicity compared to ionic NONOates. iii. Evaluation of mechanism of action of JS-K. JS-K (O²-(2,4-dinitrophenyl)-1-[(4-ethoxycarbonyl)-piperazin-1-yl]-diazeniumdiolate) has previously been found to be highly cytotoxic in many cancer cell lines compared to ionic diazeniumdiolates. Thus, the role of NO in cytotoxicity of JS-K was explored. A low intracellular NO flux in combination with a lack of any effect on cyclic guanosine monophosphate (cGMP) dependent pathway suggests that NO is not directly responsible for the cytotoxicity of JS-K.

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22

Kohr, Mark Jeffrey Jr. "Modulation of Cardiac Contraction by Reactive Nitrogen Species". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1237753236.

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23

Dangbegnon, Julien Kouadio. "Photoluminescence study of ZnO doped with nitrogen and arsenic". Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/1216.

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In this work, the optical properties of ZnO doped with arsenic and nitrogen were studied. The ZnO samples were grown by Metalorganic Chemical Vapor Deposition (MOCVD). The solubility of nitrogen in the ZnO films, as well as its activation upon annealing, was also investigated. Hydrogen is known as a major source for passivation of the acceptors in ZnO:N. Therefore, it is crucial to dissociate the complex(es) formed by nitrogen and hydrogen and diffuse out the hydrogen in order to prevent the reformation of such complexes. High temperatures (≥ 600 C) are required for these purposes. In order to effectively remove the hydrogen impurities from the sample, it is important to know the optical fingerprints of hydrogen and its thermal stability. Therefore, the effects of annealing and hydrogen plasma treatment on bulk ZnO (hydrothermally grown) were first studied. The use of bulk material for this purpose was motivated by the well-resolved photoluminescence (PL) lines observed for bulk ZnO, which allow the identification of the different lines related to hydrogen after plasma treatment. Annealing at 850 C was effective for the removal of most of the hydrogen related transitions in the near-band-edge emission. Also, additional transitions at ~3.364 eV and ~3.361 eV were observed after hydrogen plasma treatment, which were ascribed to hydrogen-Zn vacancy complexes. In this work, a comparative study of the annealing ambient and temperature on ZnO films grown on GaAs substrate, using diethyl zinc (DEZn) and tertiary butanol (TBOH), showed that arsenic diffuses in the ZnO films and gives a shallow level in the band gap, which is involved in an acceptor-bound exciton line at 3.35 eV. This shallow level is visible when annealing is performed in oxygen, but not when annealing is performed in nitrogen, and indeed only for annealing temperatures around 550 C. However, annealing in either ambient also causes zinc to diffuse from the ZnO films into the GaAs substrate, rendering the electrical properties deduced from Hall measurements ambiguous. For ZnO:N, NO was used as both oxygen and nitrogen sources. Monitoring the concentration of nitrogen, carbon and hydrogen in the ZnO films, the formation of different complexes from these impurities were deduced. Furthermore, an investigation of the effect of annealing on the concentrations of impurities showed that their out- diffusion was strongly dependent on the crystalline quality of the ZnO films. For porous ZnO films, obtained at low growth temperatures (≤310 C), the out-diffusion of impurities was efficient, whereas for films grown at higher temperatures, which have improved crystalline quality, the out-diffusion was practically nonexistent. The out-diffusion of unwanted impurities may activate the nitrogen dopant in the ZnO films, as was confirmed by the PL measurements on the different samples grown at different temperatures. PL transitions at ~3.24 eV and ~3.17 eV were related to substitutional NO. These transitions were more dominant in the spectra of samples grown at low temperatures. An additional transition at ~3.1 eV was assigned to a donor-acceptor pair transition involving VZn, instead of NO, as previously reported.

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McIntyre, Andrew D. "A study of NOâ†x monitoring using membrane amperometric gas sensors". Thesis, University of Strathclyde, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249766.

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Wellenius, Patrick. "Nitrogen Doping and Ion Beam Processing of Zinc Oxide Thin Films". NCSU, 2006. http://www.lib.ncsu.edu/theses/available/etd-01042006-015801/.

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The modification of single crystal epitaxial ZnO thin films grown by Pulsed Laser Deposition on c-axis oriented sapphire substrates by Ion Beam Processing was investigated. Nitrogen doping of the films was attempted using nuclear transmutation using the ¹⁶O (³He, ⁴He) ¹⁵O reaction at 6.6 MeV. The ¹⁵O product is unstable and decays to ¹⁵N after several minutes by positron emission. There are several potential advantages to using nuclear transmutation including producing nitrogen atoms on the correct lattice site for doping and reduced crystal damage as compared to conventional ion beam implantation. In the experiments in this thesis the doping levels achieved ~10¹⁴ cm^-3 were too low to be expected to dope the films to p-type. However several beneficial effects due to the ion beam processing were observed, including large increases in resistivity, reduction of defect luminescence, and substantial increases in the response of photoconductive detectors. In addition to desired effects in some films it was also found that in some films bubble like structures approximately 10 ìm in diameter were formed where the thin film delaminated from the surface. It was assumed that mechanism for the bubble formation was the build up of helium gas at the sapphire/ZnO interface.

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26

Kenny, Carolyn. "Nitrogen transformation processes and nitrous oxide evolution in estuarine intertidal zones". Thesis, Royal Holloway, University of London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417365.

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Hollman, Derek James. "AQUEOUS NITRIC OXIDE AUTOXIDATION: EVIDENCE AGAINST THE PRODUCTION OF NITROGEN DIOXIDE". Thesis, The University of Arizona, 2009. http://hdl.handle.net/10150/192491.

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Molloy, Brendan. "Nitrogen heterocycles as potential metal sequestering agents". Thesis, Manchester Metropolitan University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369438.

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Dorris, Kevin Scott. "A possible new source of nitrogen oxides : atmospheric electrical corona". Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/25885.

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30

Rahn, Thomas A. "Enrichment of ¹⁵N and ¹⁸O in stratospheric nitrous oxide : observations, experimental results, and implications /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9907828.

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Demoncheaux, Eric Arthur Germain. "Physico-chemical properties of nitrogen monoxide : implication for its role as a vasodilator". Thesis, Anglia Ruskin University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264045.

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32

Bird, Deborah Jane. "Experimental and modelling studies of nitrogen oxides of interest in the atmosphere". Thesis, University of York, 1995. http://etheses.whiterose.ac.uk/10856/.

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Munro, Andrew P. "S-nitrosothiols : novel decomposition pathways including reactions with sulfur and nitrogen nucleophiles". Thesis, Durham University, 1999. http://etheses.dur.ac.uk/4605/.

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Spectrophotometric (including stopped-flow) techniques were used to examine the kinetics of NO-group transfer reactions (transnitrosation) between S-nitrosothiols (RSNO) and a wide range of sulfur/nitrogen nucleophiles in aqueous solution. A metal-ion chelator was added in all experiments to prevent RSNO decay and NO liberation catalysed by copper ions. In most cases reaction was envisaged as rate- determining attack of the nucleophile at the nitrogen atom of the -SNO moiety, and hence S-nitrosothiols essentially acted as electrophilic nitrosating agents. Sulfite, thiosulfate, thiourea, thiocyanate and thiomethoxide, were sufficiently nucleophilic to induce nitrosothiol decomposition at physiological pH. Reaction with sulfide (pH > 7.4) afforded the orange-yellow anion, SSNO, and embodies a potential quantitative test for RSNOs. S-Nitrosopenicillamine was reactive enough to allow a thorough investigation into its reaction at basic pH with primary, secondary (creating carcinogenic N-nitrosamines), and tertiary amines, as well as ambident (e.g. thiomorpholine) and alpha nucleophiles (e.g. azide ion). Parallels could be made with analogous studies using other nitroso compounds such as MNTS. The generality of the reaction of a S-nitrosothiol with a large excess of the corresponding or a different thiol was also assessed. Ammonia and not nitric oxide was confirmed as the primary nitrogenous product of this highly complicated process. Mechanistic details of the copper(I) catalysed decomposition of some novel S- nitroso derivatives (e.g. a synthesised S-nitroso-1 -thiosugar) are reported. The two- stage degradation pathway involved an initial Cu(^+) promoted component that halted at incomplete conversion, and was accompanied by a large thermal reaction. An explanation of this unique pattern has been offered in terms of the generation of a disulfide-Cu(^2+) complex, in which copper is/is not accessible to reduction.

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34

Dahlberg, Tobias. "The first order Raman spectrum of isotope labelled nitrogen-doped reduced graphene oxide". Thesis, Umeå universitet, Institutionen för fysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-116699.

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The topic of this thesis is the study of nitrogen functionalities in nitrogen-doped reduced graphene oxide using Raman spectroscopy. Specifically, the project set out to investigate if the Raman active nitrogen-related vibrational modes of graphene can be identified via isotope labelling. Previous studies have used Raman spectroscopy to characterise nitrogen doped graphene, but none has employed the method of isotope labelling to do so. The study was conducted by producing undoped, nitrogen-doped and nitrogen-15-doped reduced graphene oxide and comparing the differences in the first-order Raman spectrum of the samples. Results of this study are inconclusive. However, some indications linking the I band to nitrogen functionalities are found. Also, a hypothetical Raman band denoted I* possibly related to \spt{3} hybridised carbon is introduced in the same spectral area as I. This indication of a separation of the I band into two bands, each dependent on one of these factors could bring clarity to this poorly understood spectral area. As the results of this study are highly speculative, further research is needed to confirm them and the work presented here serves as a preliminary investigation.

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35

Walker, D. J. W. "Spectroscopic studies of four wave mixing and its application to velocimetry and combustion species detection". Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389041.

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36

Ding, Guangwei, i 丁光炜. "Deep level transient spectroscopic study of nitrogen-implanted ZnO single crystal". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45541590.

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Forte, Pablo E. "Measurement of nitric oxide synthesis in humans using Â¹âµN nitrogen isotopes". Thesis, Queen Mary, University of London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325687.

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Hussain, Nibras. "The Dynamic Behaviour of a Nitrogen Oxide Trap for Direct Injection Gasoline Engine". Thesis, University of Sussex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487971.

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39

Malone, John P. "Measuring the factors controlling the production of nitrogen and nitrous oxide in soils". Thesis, Queen's University Belfast, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361223.

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40

DeCerbo, Jennifer N. "Development and Characterization of Layered, Nitrogen-Doped Hafnium Oxide and Aluminum Oxide Films for Use as Wide Temperature Capacitor Dielectrics". University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1429979783.

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Rendon, Arturo Keer. "Fundamentals of low NOx burners". Thesis, University of Sheffield, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387763.

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Pappas, Dimitrios. "Synthesis and Characterization of Novel Titanium Oxide Nanotubes - Applications as Catalyst Support for the Selective Catalytic Reduction of Nitrogen Oxides". University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397233960.

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43

Khan, Gulzar Ahmed. "Acidification and nitrogen oxide : a survey of Asian soils and the effects of nitric oxide on fungi in an experimental model". Thesis, King's College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265830.

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Cowan, Nicholas Jon. "Spatial variability of nitrous oxide flux measurements at the plot, field and farm scale". Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/10442.

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Nitrous oxide (N2O) is a potent greenhouse gas (GHG) which is released naturally into the atmosphere as a by-product of the microbial processes of nitrification and denitrification. Agricultural activities are believed to account for up to 80% of anthropogenic N2O emissions at a global scale; however, these estimates are prone to large uncertainties due to the large temporal and spatial variability associated with flux measurements. This thesis contains five studies which aimed to improve the ability to measure and predict N2O emissions from agricultural activities. A closed loop dynamic chamber was developed using a quantum cascade laser (QCL). This method provided high precision chamber measurements of N2O flux from soils with a detection limit below 4 μg N2O-N m-2 h-1. Using the dynamic chamber method allowed for a detailed investigation of uncertainties in individual measurements including contributions from regression fitting, temperature and pressure. The lack of negative fluxes measured that were outwith the detection limits of the methodology (0.3% of all measurements) highlighted that the uptake of N2O reported in some previous literature is likely to have been the result of detection limits of measurement methods applied. Spatial variability of N2O flux was investigated at the plot, field and farm scale. Fluxes were measured from a grassland field plot before and after a tillage event. These measurements highlighted the large spatially variability present in N2O fluxes from agricultural soils. Fluxes varied by up to three orders of magnitude over distances less than 5 metres after the tillage event. A field scale experiment carried out on grazed grassland investigated relationships between soil properties and N2O flux. This study found that N2O emissions correlated strongly with available nitrogen content in the soil and that animal waste was likely responsible for the spatial variability of N2O flux observed at the field scale. A farm scale inventory of N2O emissions was carried out investigating several large point sources of N2O and emissions from the wider field coverage. The inventory estimates that nitrogen fertiliser application is the single largest N2O source from the livestock farm accounting for 49% of annual emissions.

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45

Auger, Christopher. "Biochemical Adaptations in Pseudomonas fluorescens Exposed to Nitric Oxide, an Endogenous Antibacterial Agent". Thesis, Laurentian University of Sudbury, 2014. https://zone.biblio.laurentian.ca/dspace/handle/10219/2203.

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Nitric oxide (NO), a free radical released by macrophages (a subset of white blood cells) as a response to infection, is noxious to organisms due to its ability to disable crucial biomolecules such as lipids, proteins and DNA. Although normally effective at eradicating invading bacteria, several pathogens have developed mechanisms to detoxify NO and its toxic by-products, reactive nitrogen species (RNS). While some of these detoxification processes have been characterized, very little is known about the metabolic changes that enable microbes to survive this deleterious environment. Investigations into the effects of RNS on microbial physiology have shown that these harmful radicals inactivate the citric acid cycle and oxidative phosphorylation, the series of reactions responsible for making energy aerobically. The central aim of this thesis was to determine how the organism counteracts the detrimental effects of RNS, while bypassing the ineffective central metabolic pathways. The findings presented herein show that P. fluorescens engineers an elaborate metabolic network to generate ATP whilst withstanding the injurious effects of nitrosative stress. Crucial to this adaptation is the ability to produce energy via substrate level phosphorylation, a necessity that arises out of the cells’ inability to produce a substantial amount of ATP using the electron transport chain (ETC). The up-regulation of the enzymes citrate lyase (CL), phosphoenolpyruvate carboxylase (PEPC) and pyruvate, phosphate dikinase (PPDK) helps the organism accomplish this feat. Blue native polyacrylamide gel electrophoresis (BN-PAGE), high performance liquid chromatography (HPLC) as well as co-immunoprecipitation (CO-IP) studies were applied to demonstrate that these proteins form a metabolon, a transient complex of enzymes that ensures citrate is converted into its desired end products, pyruvate and ATP. In order to gauge the individual contributions iv of phosphoenolpyruvate-dependent kinases, a novel in-gel activity assay was developed to probe these enzymes under disparate conditions. These results suggest that the organism switches from an ATP-dependent metabolism to one based on the utilization of pyrophosphate (PPi). The rationale for this appears to be energy efficiency, as pyrophosphate-dependent glycolysis can theoretically produce five ATP rather than the two yielded by Embden-Meyerhof glycolysis. Additionally, the up-regulation in activity of the enzymes adenylate kinase, nucleoside diphosphate kinase and acetate kinase seem to ensure that ATP generated by PPDK is properly shuttled and stored when aerobic metabolism is defective. The lower activity of inorganic pyrophosphatase likely ensures an adequate supply of pyrophosphate for the activity of PPDK. Taken together, this research reveals the critical role metabolism plays in the survival of microbes under the onslaught of NO and RNS. As several of these enzymes are absent in mammalian systems, they present themselves as novel targets for the development of new antibacterial agents. A comprehensive awareness of bacterial defense systems in response to NO may lay the groundwork to developing more effective treatments to impede microbial infections.

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46

Bergman, Ola. "Studies of oxide reduction and nitrogen uptake in sintering of chromium-alloyed steel powder". Licentiate thesis, KTH, Materials Science and Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9555.

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The powder metallurgy (PM) process route is very competitive for mass production of structural steel components with complex shape, due to efficient material utilisation, low energy consumption, and short overall production time. The most commonly used alloying elements are the processing friendly metals Cu, Ni and Mo. However, the prices for these metals are today high and volatile, which threatens to make the PM process less competitive compared to conventional metal forming processes. Consequently, there is a strong desire in the PM industry to increase the use of less costly alloying elements. Cr is an attractive alternative since it, besides low cost, provides high hardenability and also recyclable components. The drawback is that Cr has high affinity for oxygen, which makes oxidation and oxide reduction in PM processing of Cr-alloyed materials a challenging issue. Furthermore, the interaction between nitrogen and Cr-alloyed powder during processing is important to consider, since Cr also has high nitrogen affinity and is prone to form nitrides.

The aim of the research work presented in this thesis was to study oxide reduction and nitrogen uptake in sintering of Cr-alloyed steel powder. Water-atomized powder grades pre-alloyed with 1.5-3% Cr were used as test materials. Sintering experiments were performed in N₂/H₂ (90/10) atmospheres with test bars pressed to density 7.0-7.2 g/cm3. The oxygen content of the sintering atmosphere was varied and different sintering temperatures and cooling rates were applied. The experimental study has been complemented with thermodynamic calculations using the software Thermo-Calc.

The oxygen partial pressure should be below 4 x 10^-18 atm in order to have reducing conditions during sintering at 1120°C of steel powder pre-alloyed with 3% Cr. With graphite added to the powder, conditions are reducing at higher oxygen partial pressures (up to 10^-16 atm) due to favourable conditions locally in the material. Sintering at 1120°C for 30 minutes leads to incomplete reduction of Cr-oxides in the Cr-alloyed PM grades, but remaining oxides are not detrimental for mechanical properties of the PM components. Increased sintering temperature is beneficial for the oxide reduction kinetics and practically all oxides are reduced after sintering for 30 minutes above 1200°C. Nitrogen uptake by Cr-alloyed steel powder from N₂-based sintering atmospheres is strongly dependent on the cooling rate applied after sintering. No nitrides appear in the sintered material and mechanical properties are not affected when normal cooling rates (0.5-1°C/s) are applied. Very low cooling rates (such as 0.05°C/s) may lead to grain boundary precipitation of Cr-nitrides in the sintered material.

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47

Ali, Ahlam Abdunnabi. "The contribution of reactive nitrogen species to the cytotoxicity of nitric oxide generating therapy". Thesis, Queen's University Belfast, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598021.

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Nitric oxide (NO) has become increasingly recognized throughout the past decade for its role in many patho-physiologies. NO delivery has been investigated as a potential therapeutic strategy against solid tumours, using both NO donor drugs and gene therapy strategies. This project aims to study the importance of oxygen concentration and the possible role of key reaction products involved in NO induced cytotoxicity. Utilising the NO donor drug, DETA/NO the effects of oxygen tension on the cytotoxicity was investigated in vitro. The find ings presented in this study indicate that the DETA/NO mediated cytotoxic effects in all the tumour cell lines tested was significantly more toxic under severe hypoxia. This effect was most evident at drug concentrations greater than 10 ~M. Both the intrinsic and extrinsic apoptotic pathways were activated fo llowing DETA/NO treatment, and cleavage of apoptotic proteins was enhanced under hypoxia. DETA/NO treatment under hypoxia significantly destabilized hypoxia inducible factor (HIF-1a) and resulted in the accumulation of p53 protein. Investigations into the contribution of reactive nitrogen species to NO' cytotoxicity revealed that neither peroxynitrite (ONOO-) nor Nitroxyl (HNO) was generated. Fluorometric analysis in the presence of dinitrogen trioxide (N,O,) scavengers suggests for the first time that N,O, may be responsible for the cytotoxicity with DETA/NO. Compelling evidence is provided to suggest that S-nitrosylation is the key molecular mechanism involved in NO signalling. This is the fi rst study that shows significant Snitrosothiol formation in cancer cells when exposed to high levels of NO irrespective of oxygen concentration. Further investigations revealed that both nuclear p53, and GAPDH proteins are targets for S-nitrosylation following treatment with DETA/NO, and may possibly play a key role in DETA/NO-mediated apoptosis and cytotoxicity.

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Yonker, Justin David. "Contribution of the First Electronically Excited State of Molecular Nitrogen to Thermospheric Nitric Oxide". Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/22039.

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The chemical reaction of the first excited electronic state of molecular nitrogen, N2(A), with ground state atomic oxygen is an important contributor to thermospheric nitric oxide (NO). The importance is assessed by including this reaction in a one-dimensional photochemical model. The method is to scale the photoelectron impact ionization rate of molecular nitrogen by a Gaussian centered near 100 km.

Large uncertainties remain in the temperature dependence and branching ratios of many reactions important to NO production and loss. Similarly large uncertainties are present in the solar soft x-ray irradiance, known to be the fundamental driver of the low-latitude NO. To illustrate, it is shown that the equatorial, midday NO density measured by the Student Nitric Oxide Explorer (SNOE) satellite near the Solar Cycle 23 maximum can be recovered by the model to within the 20% measurement uncertainties using two rather different but equally reasonable chemical schemes, each with their own solar soft-xray irradiance parameterizations. Including the N2(A) changes the NO production rate by an average of 11%, but the NO density changes by a much larger 44%. This is explained by tracing the direct, indirect, and catalytic contributions of N2(A) to NO, finding them to contribute 40%, 33%, and 27% respectively.

The contribution of N2(A) relative to the total NO production and loss is assessed by tracing both back to their origins in the primary photoabsorption and photoelectron impact processes. The photoelectron impact ionization of N2 is shown to be the main driver of the midday NO production while the photoelectron impact dissociation of N2 is the main NO destroyer. The net photoelectron impact excitation rate of N2, which is responsible for the N2(A) production, is larger than the ionization and dissociation rates and thus potentially very important. Although the conservative assumptions regarding the level-specific NO yield from the N2(A)+O reaction results in N2(A) being a somewhat minor contributor, N2(A) production is found to be the most efficient producer of NO among the thermospheric energy deposition processes.
Ph. D.

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49

Bergman, Ola. "Studies of oxide reduction and nitrogen uptake in sintering of chromium-alloyed steel power /". Stockholm : Materialvetenskap, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9555.

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50

Rubol, Simonetta. "The influence of redox dynamics on nitrogen cycling and nitrous oxide emissions from soils". Doctoral thesis, Università degli studi di Trento, 2010. https://hdl.handle.net/11572/368271.

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Soils are a dominant source of nitrous oxide (N2O), a potent greenhouse gas. The complexity of drivers of N2O production and emissions has hindered our ability to predict the magnitude and spatial dynamics of N2O fluxes. Soil moisture can be considered a key driver because it influences oxygen supply, which feeds back on N2O sources (nitrification versus denitrification) and sinks (reduction to dinitrogen). Soil volumetric water content is directly linked to dissolved oxygen and to redox potential, which regulate microbial metabolism and chemical transformations in the environment. The relationship between soil moisture and N2O is usually based on incubations of soil at different soil moisture levels. Few studies have focused on the interaction between soil moisture and nitrogen dynamics in the vadose zone. In this thesis soil column and chamber experiments were performed in order to investigate the relationship of soil moisture dynamics to redox sensitive nitrogen dynamics in the organic matter layer of a pasture peatland in Sacramento, Bay Delta area, California. Field data has been analyzed and statistics has been used to evaluate the influence of irrigation practices on spatial pattern of measurements. Data indicate that organic peatland might be an important source of nitrous oxide emissions. The comparison of rainfall, saturation and deposition shown that trace gases emissions, dissolved nitrate and ammonium changed considerably along the soil column profile as a response of the microbial community to the high variability in redox, soil moisture, oxygen experienced by the soil at different depth. Water movement favored the formation of zones at different redox condition, redistributed the nutrient along the soil profile, and considerably changed mineralization,nitrification and dissimilatory reduction to nitrate (DNRA) rates. It was observed an asymmetrical behavior between nitrogen and ammonium profiles. Experiments shown that this assimetry is a function of the degree of saturation (as well as its duration). Also the fraction of the total N2O that is actually emitted to the atmosphere depends heavily on the structure and wetness of the soil. The nitrous oxide dynamic is therefore a function of the antecedent wetness condition, the nutrient content of the peat-land, the physical characteristics of the peat-land and the vertical stratification of layers at different redox and oxygen condition, which may affect the annual N budget. In addition, the combined use of soil column and chamber experiments suggest a negative correlation between soil moisture and N2O in dynamic condition and a functional dependence of N2O emissions from the oxygen concentration. We found that the time scale of water dynamic was faster than the biological scale of trace gas emissions. Finally, the relationship of nitrous oxide versus water content was reproduced by using a lumped model which include oxygen dynamic. Preliminary results suggest that by accounting for oxygen dynamic, it is possible to reproduce the functional behavior observed in the experiment and that the latter is depending on the physical and biological properties of the soil. Keywords: water dynamics, nitrous oxide emissions, nitrate ammonification,feammox, denitrification, soil heterogeneity, oxygen, redox.

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