WorldWideScience

Sample records for estimate nitrous oxide

  1. Estimation of methane and nitrous oxide emissions from Indian livestock.

    Science.gov (United States)

    Patra, Amlan K

    2012-10-26

    Greenhouse gas (GHG; methane and nitrous oxide) emissions from enteric fermentation and manure management of Indian livestock were estimated from the last two Indian livestock census datasets (2003 and 2007) using IPCC Tier 2 (2006) guidelines. The total annual GHG emissions from Indian livestock increased in 2007 compared to the year 2003 with an annual growth rate of 1.52% over this period. The contributions of GHG by dairy cattle, non-dairy cattle, buffaloes, goats, sheep and other animals (yak, mithun, horse, donkeys, pigs and poultry) were 30.52, 24.0, 37.7, 4.34, 2.09 and 3.52%, respectively, in 2007. Enteric fermentation was the major source of methane, accounting for 89.2% of the total GHG emissions, followed by manure methane (9.49%). Nitrous oxide emissions accounted for 1.34%. GHG emissions (CO(2)-eq. per kg of fat and protein corrected milk (FPCM)) by female animals were considerably lower for crossbred cows (1161 g), followed by buffaloes (1332 g) and goats (2699 g), and were the highest for indigenous cattle (3261 g) in 2007. There was a decreasing trend in GHG emissions (-1.82% annual growth rate) in relation to milk production from 2003 to 2007 (1818 g and 1689 g CO(2)-eq. per kg FPCM in 2003 and 2007, respectively). This study revealed that GHG emissions (total as well as per unit of products) from dairy and other categories of livestock populations could be reduced substantially through proper dairy herd management without compromising animal production. In conclusion, although the total GHG emissions from Indian livestock increased in 2007, there was a decreasing trend in GHG production per kg of milk production or animal products.

  2. Method to estimate direct nitrous oxide emissions from agricultural soils

    NARCIS (Netherlands)

    Bouwman AF; LAE

    1994-01-01

    This analysis was based on a review of published measurements of nitrous oxide (N2O) emission from fertilized fields. From the literature data selections were made to analyze the importance of factors that regulate N2O production, including soil conditions, type of crop, nitrogen (N) fertilizer type

  3. Nitrous Oxide Flux

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Nitrous Oxide (N20) flux is the net rate of nitrous oxide exchange between an ecosystem and the atmosphere. Data of this variable were generated by the USGS...

  4. Estimating global nitrous oxide emissions by lichens and bryophytes with a process-based productivity model

    Science.gov (United States)

    Porada, Philipp; Pöschl, Ulrich; Kleidon, Axel; Beer, Christian; Weber, Bettina

    2017-04-01

    Lichens and bryophytes have been shown to release significant amounts of nitrous oxide (N2O), which is a strong greenhouse gas and atmospheric ozone - depleting agent. Relative contributions of lichens and bryophytes to nitrous oxide emissions are largest in dryland and tundra regions, with potential implications for the nitrogen balance of these ecosystems. So far, this estimate is based on large-scale values of net primary productivity of lichens and bryophytes, which are derived from empirical upscaling of field measurements. Productivity is then converted to nitrous oxide emissions by empirical relationships between productivity and respiration, as well as respiration and nitrous oxide release. Alternatively, we quantify nitrous oxide emissions using a global process-based non-vascular vegetation model of lichens and bryophytes. The model simulates photosynthesis and respiration of lichens and bryophytes directly as a function of climatic conditions, such as light and temperature. Nitrous oxide emissions are then derived from simulated respiration, assuming a fixed relationship between the two fluxes, which is based on laboratory experiments under varying environmental conditions. Our approach yields a global estimate of 0.27 (0.19 - 0.35) Tg N2O yr-1 released by lichens and bryophytes. This is at the lower end of the range of a previous, empirical estimate, but corresponds to about 50 % of the atmospheric deposition of nitrous oxide into the oceans or 25 % of the atmospheric deposition on land. We conclude that, while productivity of lichens and bryophytes at large scale is relatively well constrained, improved estimates of their respiration may help to reduce uncertainty of predicted N2O emissions. This is particularly important for quantifying the spatial distribution of N2O emissions by lichens and bryophytes, since simulated respiration shows a different global pattern than productivity. We find that both physiological variation among species as well as

  5. Death from Nitrous Oxide.

    Science.gov (United States)

    Bäckström, Björn; Johansson, Bengt; Eriksson, Anders

    2015-11-01

    Nitrous oxide is an inflammable gas that gives no smell or taste. It has a history of abuse as long as its clinical use, and deaths, although rare, have been reported. We describe two cases of accidental deaths related to voluntary inhalation of nitrous oxide, both found dead with a gas mask covering the face. In an attempt to find an explanation to why the victims did not react properly to oncoming hypoxia, we performed experiments where a test person was allowed to breath in a closed system, with or without nitrous oxide added. Vital signs and gas concentrations as well as subjective symptoms were recorded. The experiments indicated that the explanation to the fact that neither of the descendents had reacted to oncoming hypoxia and hypercapnia was due to the inhalation of nitrous oxide. This study raises the question whether nitrous oxide really should be easily, commercially available. © 2015 American Academy of Forensic Sciences.

  6. Estimation of methane and nitrous oxide emissions from rice field with rice straw management in Cambodia.

    Science.gov (United States)

    Vibol, S; Towprayoon, S

    2010-02-01

    To estimate the greenhouse gas emissions from paddy fields of Cambodia, the methodology of the Intergovernmental Panel on Climate Change (IPCC) guidelines, IPCC coefficients, and emission factors from the experiment in Thailand and another country were used. Total area under rice cultivation during the years 2005-2006 was 2,048,360 ha in the first crop season and 298,529 ha in the second crop season. The emission of methane from stubble incorporation with manure plus fertilizer application areas in the first crop season was estimated to be 192,783.74 ton higher than stubble with manure, stubble with fertilizer, and stubble without fertilizer areas. The fields with stubble burning emitted the highest emission of methane (75,771.29 ton) followed by stubble burning with manure (22,251.08 ton), stubble burning with fertilizer (13,213.27 ton), and stubble burning with fertilizer application areas (3,222.22 ton). The total emission of methane from rice field in Cambodia for the years 2005-2006 was approximately 342,649.26 ton (342.65 Gg) in the first crop season and 36,838.88 ton (36.84 Gg) in the second crop season. During the first crop season in the years 2005-2006, Battambang province emitted the highest amount of CH(4) (38,764.48 ton) and, in the second crop season during the years 2005-2006, the highest emission (8,262.34 ton) was found in Takeo province (8,262.34 ton). Nitrous oxide emission was between 2.70 and 1,047.92 ton in the first crop season and it ranged from 0 to 244.90 ton in the second crop season. Total nitrous oxide emission from paddy rice field was estimated to be 9,026.28 ton in the first crop season and 1,091.93 ton in the second crop season. Larger area under cultivation is responsible for higher emission of methane and nitrous oxide. Total emission of nitrous oxide by using IPCC default emission coefficient was approximately 2,328.85 ton. The total global warming potential of Cambodian paddy rice soil is 11,723,217.03 ton (11,723 Gg

  7. Nitrous Oxide Micro Engines Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nitrous Oxide Micro Engines (NOME) are a new type of nitrous oxide dissociation thruster designed to generate low levels of thrust that can be used for RCS control...

  8. Catalytic oxidation using nitrous oxide

    Directory of Open Access Journals (Sweden)

    Juan Carlos Beltran-Prieto

    2017-01-01

    Full Text Available Nitrous oxide is a very inert gas used generally as oxidant as it offers some advantage compared with other oxidants such as O2 but a considerably higher temperature (> 526 °C is often required. For particular cases such as the oxidation of sugar alcohols, especially for the oxidation of primary alcohols to aldehydes, N2O has the advantage over O2 of a higher reaction selectivity. In the present paper we present the modelling of oxidation reaction of sugar alcohols using an oxidizing agent in low concentrations, which is important to suppress subsequent oxidation reactions due to the very low residual concentrations of the oxidizing agent. For orientation experiments we chose nitrous oxide generated by thermal decomposition of ammonium nitrate. Kinetic modeling of the reaction was performed after determination of the differential equations that describe the system under study.

  9. Inverse Modeling Estimates of the Global Nitrous Oxide Surface Flux from 1998-2001

    NARCIS (Netherlands)

    Hirsch, A.; Michalak, A.; Bruhwiler, L.; Peters, W.; Dlugokencky, E.; Tans, P.P.

    2006-01-01

    Measurements of nitrous oxide in air samples from 48 sites in the Cooperative Global Air Sampling Network made by NOAA/ESRL GMD CCGG (the Carbon Cycle Greenhouse Gases group in the Global Monitoring Division at the NOAA Earth System Research Laboratory in Boulder, Colorado) and the three-dimensional

  10. Eddy covariance observations of methane and nitrous oxide emissions : Towards more accurate estimates from ecosystems

    NARCIS (Netherlands)

    Kroon-van Loon, P.S.

    2010-01-01

    About 30% of the increased greenhouse gas (GHG) emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are related to land use changes and agricultural activities. In order to select effective measures, knowledge is required about GHG emissions from these ecosystems and how these

  11. Development and application of a detailed inventory framework for estimating nitrous oxide and methane emissions from agriculture

    Science.gov (United States)

    Wang, Junye; Cardenas, Laura M.; Misselbrook, Tom H.; Gilhespy, Sarah

    2011-03-01

    A detailed inventory framework was developed to estimate nitrous oxide (N2O) and methane (CH4) emissions from UK agriculture using the IPCC approach. The inventory framework model was illustrated by combining relevant emission factors with agricultural census data for England, Wales, Scotland and Northern Ireland for the year 2000 to derive country-specific emission estimates which were summed to derive the UK total. The framework enables simple assessment to be made of the impact on national emissions of using different emission factors (EFs) (e.g. site- or local-specific compared with IPCC default factors). The framework was used to calculate the average annual emissions of nitrous oxide (N2O) and methane (CH4) for specific livestock and crops, and amounts lost through volatilisation, leaching and runoff for each country in the UK. The framework provides a simple, realistic and transparent approach to estimating national emissions and can easily be updated.

  12. Preindustrial nitrous oxide emissions from the land biosphere estimated by using a global biogeochemistry model

    Science.gov (United States)

    Xu, Rongting; Tian, Hanqin; Lu, Chaoqun; Pan, Shufen; Chen, Jian; Yang, Jia; Zhang, Bowen

    2017-07-01

    To accurately assess how increased global nitrous oxide (N2O) emission has affected the climate system requires a robust estimation of the preindustrial N2O emissions since only the difference between current and preindustrial emissions represents net drivers of anthropogenic climate change. However, large uncertainty exists in previous estimates of preindustrial N2O emissions from the land biosphere, while preindustrial N2O emissions on the finer scales, such as regional, biome, or sector scales, have not been well quantified yet. In this study, we applied a process-based Dynamic Land Ecosystem Model (DLEM) to estimate the magnitude and spatial patterns of preindustrial N2O fluxes at the biome, continental, and global level as driven by multiple environmental factors. Uncertainties associated with key parameters were also evaluated. Our study indicates that the mean of the preindustrial N2O emission was approximately 6.20 Tg N yr-1, with an uncertainty range of 4.76 to 8.13 Tg N yr-1. The estimated N2O emission varied significantly at spatial and biome levels. South America, Africa, and Southern Asia accounted for 34.12, 23.85, and 18.93 %, respectively, together contributing 76.90 % of global total emission. The tropics were identified as the major source of N2O released into the atmosphere, accounting for 64.66 % of the total emission. Our multi-scale estimates provide a robust reference for assessing the climate forcing of anthropogenic N2O emission from the land biosphere

  13. Nitrous oxide and perioperative outcomes.

    Science.gov (United States)

    Ko, Hanjo; Kaye, Alan David; Urman, Richard D

    2014-06-01

    There is emerging evidence related to the effects of nitrous oxide on important perioperative patient outcomes. Proposed mechanisms include metabolic effects linked to elevated homocysteine levels and endothelial dysfunction, inhibition of deoxyribonucleic acid and protein formation, and depression of chemotactic migration by monocytes. Newer large studies point to possible risks associated with the use of nitrous oxide, although data are often equivocal and inconclusive. Cardiovascular outcomes such as stroke or myocardial infarction were shown to be unchanged in previous studies, but the more recent Evaluation of Nitrous Oxide in the Gas Mixture for Anesthesia I trial shows possible associations between nitrous oxide and increased cardiovascular and pulmonary complications. There are also possible effects on postoperative wound infections and neuropsychological function, although the multifactorial nature of these complications should be considered. Teratogenicity linked to nitrous oxide use has not been firmly established. The use of nitrous oxide for routine anesthetic care may be associated with significant costs if complications such as nausea, vomiting, and wound infections are taken into consideration. Overall, definitive data regarding the effect of nitrous oxide on major perioperative outcomes are lacking. There are ongoing prospective studies that may further elucidate its role. The use of nitrous oxide in daily practice should be individualized to each patient's medical conditions and risk factors.

  14. 21 CFR 184.1545 - Nitrous oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nitrous oxide. 184.1545 Section 184.1545 Food and... Substances Affirmed as GRAS § 184.1545 Nitrous oxide. (a) Nitrous oxide (empirical formula N2O, CAS Reg. No.... Nitrous oxide is manufactured by the thermal decomposition of ammonium nitrate. Higher oxides of nitrogen...

  15. Nitrous oxide emission by aquatic macrofauna

    DEFF Research Database (Denmark)

    Stief, Peter; Poulsen, Morten; Nielsen, Lars Peter

    2009-01-01

      A large variety of aquatic animals was found to emit the potent greenhouse gas nitrous oxide when nitrate was present in the environment. The emission was ascribed to denitrification by ingested bacteria in the anoxic animal gut, and the exceptionally high N2O-to-N2 production ratio suggested...... delayed induction of the last step of denitrification. Filter- and deposit-feeding animal species showed the highest rates of nitrous oxide emission and predators the lowest, probably reflecting the different amounts of denitrifying bacteria in the diet. We estimate that nitrous oxide emission by aquatic...... animals is quantitatively important in nitraterich aquatic environments like freshwater, coastal marine, and deep-sea ecosystems. The contribution of this source to overall nitrous oxide emission from aquatic environments might further increase because of the projected increase of nitrate availability...

  16. Nitrous oxide emission by aquatic macrofauna

    Science.gov (United States)

    Stief, Peter; Poulsen, Morten; Nielsen, Lars Peter; Brix, Hans; Schramm, Andreas

    2009-01-01

    A large variety of aquatic animals was found to emit the potent greenhouse gas nitrous oxide when nitrate was present in the environment. The emission was ascribed to denitrification by ingested bacteria in the anoxic animal gut, and the exceptionally high N2O-to-N2 production ratio suggested delayed induction of the last step of denitrification. Filter- and deposit-feeding animal species showed the highest rates of nitrous oxide emission and predators the lowest, probably reflecting the different amounts of denitrifying bacteria in the diet. We estimate that nitrous oxide emission by aquatic animals is quantitatively important in nitrate-rich aquatic environments like freshwater, coastal marine, and deep-sea ecosystems. The contribution of this source to overall nitrous oxide emission from aquatic environments might further increase because of the projected increase of nitrate availability in tropical regions and the numeric dominance of filter- and deposit-feeders in eutrophic ecosystems. PMID:19255427

  17. Resonating Nitrous Oxide Thruster Project

    Data.gov (United States)

    National Aeronautics and Space Administration — AeroAstro proposes decomposing nitrous oxide (N2O) as an alternative propellant to existing spacecraft propellants. Decomposing N2O can be used as either a high Isp,...

  18. Analysis of uncertainties in the estimates of nitrous oxide and methane emissions in the UK's greenhouse gas inventory for agriculture

    Science.gov (United States)

    Milne, Alice E.; Glendining, Margaret J.; Bellamy, Pat; Misselbrook, Tom; Gilhespy, Sarah; Rivas Casado, Monica; Hulin, Adele; van Oijen, Marcel; Whitmore, Andrew P.

    2014-01-01

    The UK's greenhouse gas inventory for agriculture uses a model based on the IPCC Tier 1 and Tier 2 methods to estimate the emissions of methane and nitrous oxide from agriculture. The inventory calculations are disaggregated at country level (England, Wales, Scotland and Northern Ireland). Before now, no detailed assessment of the uncertainties in the estimates of emissions had been done. We used Monte Carlo simulation to do such an analysis. We collated information on the uncertainties of each of the model inputs. The uncertainties propagate through the model and result in uncertainties in the estimated emissions. Using a sensitivity analysis, we found that in England and Scotland the uncertainty in the emission factor for emissions from N inputs (EF1) affected uncertainty the most, but that in Wales and Northern Ireland, the emission factor for N leaching and runoff (EF5) had greater influence. We showed that if the uncertainty in any one of these emission factors is reduced by 50%, the uncertainty in emissions of nitrous oxide reduces by 10%. The uncertainty in the estimate for the emissions of methane emission factors for enteric fermentation in cows and sheep most affected the uncertainty in methane emissions. When inventories are disaggregated (as that for the UK is) correlation between separate instances of each emission factor will affect the uncertainty in emissions. As more countries move towards inventory models with disaggregation, it is important that the IPCC give firm guidance on this topic.

  19. Nitrous oxide emissions from estuarine intertidal sediments

    NARCIS (Netherlands)

    Middelburg, J.J.; Klaver, G.; Nieuwenhuize, J.; Markusse, R.M.; Vlug, T.; Nat, F.J.W.A. van der

    1995-01-01

    From September 1990 through December 1991 nitrous oxide flux measurements were made at 9 intertidal mud flat sites in the Scheldt Estuary. Nitrous oxide release rates were highly variable both between sites and over time at any one site. Annual nitrous oxide fluxes vary from about 10 mmol N m-2 at

  20. 29 CFR 1910.105 - Nitrous oxide.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Nitrous oxide. 1910.105 Section 1910.105 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Hazardous Materials § 1910.105 Nitrous oxide. The piped systems for the in-plant transfer and distribution of nitrous oxide shall be designed, installed, maintained, and...

  1. Electron collisions with nitrous oxide

    OpenAIRE

    Winstead, Carl; McKoy, Vincent

    1998-01-01

    We have carried out theoretical studies of low-energy elastic electron collisions with nitrous oxide (N2O), obtaining differential, integral, and momentum-transfer cross sections. Polarization effects are incorporated in the electron-molecule scattering dynamics. A simple, objective, and physically motivated criterion is introduced for constructing a compact set of configurations that accurately accounts for polarization in resonant symmetries while avoiding overcorrelation. Our cross section...

  2. Intraoperative nitrous oxide as a preventive analgesic.

    Science.gov (United States)

    Stiglitz, D K; Amaratunge, L N; Konstantatos, A H; Lindholm, D E

    2010-09-01

    Preventive analgesia is defined as the persistence of the analgesic effects of a drug beyond the clinical activity of the drug. The N-methyl D-aspartate receptor plays a critical role in the sensitisation of pain pathways induced by injury. Nitrous oxide inhibits excitatory N-methyl D-aspartate sensitive glutamate receptors. The objective of our study was to test the efficacy of nitrous oxide as a preventive analgesic. We conducted a retrospective analysis of data from a subset of patients (n = 100) randomly selected from a previous major multicentre randomised controlled trial on nitrous oxide (ENIGMA trial). Data analysed included postoperative analgesic requirements, pain scores and duration of patient-controlled analgesia during the first 72 postoperative hours. There was no significant difference in postoperative oral morphine equivalent usage (nitrous group 248 mg, no nitrous group 289 mg, mean difference -43 mg, 95% confidence interval 141 to 54 mg). However, patients who received nitrous oxide had a shorter duration of patient-controlled analgesia use (nitrous group 35 hours, no nitrous group 51 hours, mean difference -16 hours, 95% confidence interval -29 to -2 hours, P = 0.022). There was no difference in pain scores between the groups. The shorter patient-controlled analgesia duration in the nitrous oxide group suggests that intraoperative nitrous oxide may have a preventive analgesic effect.

  3. Landscape-scale estimation of denitrification rates and nitrous oxide to dinitrogen ratio at Georgia and Pennsylvania LTAR sites

    Science.gov (United States)

    Dell, C. J.; Groffman, P. M.; Strickland, T.; Kleinman, P. J. A.; Bosch, D. D.; Bryant, R.

    2015-12-01

    Denitrification results in a significant loss of plant-available nitrogen from agricultural systems and contributes to climate change, due to the emissions of both the potent greenhouse gas nitrous oxide (N2O) and environmentally benign dinitrogen (N2). However total quantities of the gases emitted and the ratio of N2:N2O are often not clearly understood, because N2 emissions cannot be directly measured in the field because of the high background level of N2 in the atmosphere. While variability in soil conditions across landscapes, especially water content and aeration, is believed to greatly impact both total denitrification rates and N2:N2O, the measurement limitations have prevented a clear understanding of landscape-scale emissions of denitrification products. The Cary Institute has developed an approach where soil core are maintained in a sealed system with an N2-free airstream, allowing emitted N2 and N2O emissions to be measured without interference from atmospheric N2. Emissions of the gases are measured under a range of oxygen concentrations and soil water contents. Laboratory responses can then be correlated with measured field conditions at the sampling points and resulting emission estimates extrapolated to the field-scale. Measurements are currently being conducted on peanut/cotton rotations, dairy forage rotations (silage corn/alfalfa), and bioenergy crops (switchgrass and miscanthus) at Long Term Agricultural Research (LTAR) sites at Tifton, GA and University Park, PA.

  4. 21 CFR 868.1700 - Nitrous oxide gas analyzer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitrous oxide gas analyzer. 868.1700 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1700 Nitrous oxide gas analyzer. (a) Identification. A nitrous oxide gas analyzer is a device intended to measure the concentration of nitrous oxide...

  5. Nitrous oxide use and endotracheal tube rupture.

    Science.gov (United States)

    Mosby, E L; Schelkun, P M; Vincent, S K

    1988-01-01

    Nitrous oxide is an important and widely used anesthetic agent. However, during lengthy surgical procedures, significant amounts of nitrous oxide diffuse into the endotracheal tube cuff, causing sequelae that may include increased cuff pressures, tracheal trauma, increased postoperative discomfort, and cuff rupture. In this paper, two cases are presented in which the endotracheal tube cuff used to deliver this anesthetic agent ruptured after more than four hours of surgery. Two simple means of limiting the diffusion of nitrous oxide into the cuff and thus preventing this occurrence are described.

  6. Nitrous Oxide flux measurements under various amendments

    Data.gov (United States)

    U.S. Environmental Protection Agency — The dataset consists of measurements of soil nitrous oxide emissions from soils under three different amendments: glucose, cellulose, and manure. Data includes the...

  7. Nitrous Oxide Ethane Ethylene Engine Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Nitrous Oxide Ethane-Ethylene (NEE) engine is a proposed technology designed to provide spacecraft with non-toxic non-cryogenic high-performance propulsion. With...

  8. Global Estimation of Soil Nitrous Oxide Emission Using a Semi-Empirical Model and a Global Dataset

    Science.gov (United States)

    Hashimoto, S.

    2015-12-01

    Nitrous oxide (N2O) flux is one of the major greenhouse gas fluxes from terrestrial ecosystems. N2O is produced as a by-product of the transformations of nitrogen in the soil and is generally released from the soil surface to the atmosphere. The purpose of this study is to provide a data-oriented global estimate of N2O flux from the soil. In this study, a semi-empirical model was developed by modifying a model for soil CO2 flux (Raich et al. 2002). The model consists of the functions of nitrogen, air temperature, and precipitation. The parameters of the functions were determined using a global dataset of N2O emission (Stehfest and Bouwman 2006) through the Bayesian approach. The function of nitrogen is a function of carbon to nitrogen ratio. For agricultural land use, the effect of nitrogen fertilizer was also incorporated in the function of nitrogen. The model was applied at a spatial resolution of 5 min and at a monthly time resolution. Preliminary calculation revealed that the total amount of N2O emission was 10 Tg N yr-1. The upland natural land was the major source of N2O emission, followed by the upland agricultural land. Latitudinally, the flux was high at 30°N-40°N and 10°S-10°N. The major contribution to the peak at 30°N-40°N was by the upland agricultural land and that to the peak around the equator was by the upland natural land. The monthly flux showed a clear seasonality, and it was the highest and lowest in August and February, respectively. The global scale seasonality was mainly contributed by the N2O flux from the upland agricultural land in the northern mid-latitude. This study provides data-oriented spatiotemporal distribution of soil N2O flux, and I hope that these data will be used for a benchmark and constraint of process-based modeling.

  9. Formation of methane and nitrous oxide in plants

    Science.gov (United States)

    Keppler, Frank; Lenhart, Katharina

    2017-04-01

    Methane, the second important anthropogenic greenhouse gas after carbon dioxide, is the most abundant reduced organic compound in the atmosphere and plays a central role in atmospheric chemistry. The global atmospheric methane budget is determined by many natural and anthropogenic terrestrial and aquatic surface sources, balanced primarily by one major sink (hydroxyl radicals) in the atmosphere. Natural sources of atmospheric methane in the biosphere have until recently been attributed to originate solely from strictly anaerobic microbial processes in wetland soils and rice paddies, the intestines of termites and ruminants, human and agricultural waste, and from biomass burning, fossil fuel mining and geological sources including mud volcanoes and seeps. However, recent studies suggested that terrestrial vegetation, fungi and mammals may also produce methane without the help of methanogens and under aerobic conditions (e.g. Keppler et al. 2009, Wang et al. 2013). These novel sources have been termed "aerobic methane production" to distinguish them from the well-known anaerobic methane production pathway. Nitrous oxide is another important greenhouse gas and major source of ozone-depleting nitric oxide. About two thirds of nitrous oxide emissions are considered to originate from anthropogenic and natural terrestrial sources, and are almost exclusively related to microbial processes in soils and sediments. However, the global nitrous oxide budget still has major uncertainties since it is unclear if all major sources have been identified but also the emission estimates of the know sources and stratospheric sink are afflicted with high uncertainties. Plants contribute, although not yet quantified, to nitrous oxide emissions either indirectly as conduits of soil derived nitrous oxide (Pihlatie et al. 2005), or directly via generation of nitrous oxide in leaves (Dean & Harper 1986) or on the leaf surface induced by UV irradiation (Bruhn et al. 2014). Moreover, lichens

  10. Toward a nitrous oxide budget for a global megacity: Los Angeles, California (Invited)

    Science.gov (United States)

    Townsend-Small, A.

    2013-12-01

    Nitrous oxide is a powerful greenhouse gas (nearly 300 times as powerful as carbon dioxide) and one of the major anthropogenic ozone depleting chemicals in the atmosphere. The strong global warming potential makes it a good target for greenhouse gas emissions reductions. But although the major anthropogenic source of nitrous oxide globally is from fertilized agricultural soils, only a very few studies have attempted a regional nitrous oxide budget. Here we present a synthesis of several recent efforts to constrain nitrous oxide emissions from terrestrial soils, wastewater treatment plants, and the coastal ocean in the Los Angeles, California metro area, home to ~13 million residents. Landscaped soils such as lawns and athletic fields emit nitrous oxide at approximately the same rate as agricultural soils in the region, ~ 200 mg N m-2 yr-1. Wastewater recycling to conserve water resources in this arid region emits nitrous oxide at rates about 3 times higher than traditional carbon oxidation of wastewater, making water reclamation the dominant anthropogenic source in the region. However, we also estimated efflux of nitrous oxide from the coastal ocean using surface concentrations and estimates of wind-driven mixing, and we found that marine emissions may be up to 10 times higher than anthropogenic sources. We also measured stable isotopic composition (N-15 and O-18) of nitrous oxide from all of these sources, and we will present the implications of these and our emission rate data for top-down monitoring of regional nitrous oxide sources.

  11. High Performance Nitrous Oxide Analyzer for Atmospheric Research Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project targets the development of a highly sensitive gas sensor to monitor atmospheric nitrous oxide. Nitrous oxide is an important species in Earth science...

  12. Synthesis of triazenes with nitrous oxide.

    Science.gov (United States)

    Kiefer, Gregor; Riedel, Tina; Dyson, Paul J; Scopelliti, Rosario; Severin, Kay

    2015-01-02

    Triazenes are valuable compounds in organic chemistry and numerous applications have been reported. Furthermore, triazenes have been investigated extensively as potential antitumor drugs. Here, we describe a new method for the synthesis of triazenes. The procedure involves a reagent which is rarely used in synthetic organic chemistry: nitrous oxide (N2 O, "laughing gas"). Nitrous oxide mediates the coupling of lithium amides and organomagnesium compounds while serving as a nitrogen donor. Despite the very inert character of nitrous oxide, the reactions can be performed in solution under mild conditions. A key advantage of the new procedure is the ability to access triazenes with alkynyl and alkenyl substituents. These compounds are difficult to prepare by conventional methods because the required starting materials are unstable. Some of the new alkynyltriazenes were found to display high cytotoxicity in in vitro tests on ovarian and breast cancer cell lines. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Nitrous Oxide Production by Abundant Benthic Macrofauna

    DEFF Research Database (Denmark)

    Stief, Peter; Schramm, Andreas

    that do not ingest large quantities of microorganisms produced insignificant amounts of nitrous oxide. Ephemera danica, a very abundant mayfly larva, was monitored monthly in a nitrate-polluted stream. Nitrous oxide production by this filter-feeder was highly dependent on nitrate availability...... and temperature. Given the increasing nitrate pollution of freshwater ecosystems, the collective gut of benthic macrofauna might constitute an increasingly important yet hitherto overlooked link in the global nitrous oxide budget.......Detritivorous macrofauna species co-ingest large quantities of microorganisms some of which survive the gut passage. Denitrifying bacteria, in particular, become metabolically induced by anoxic conditions, nitrate, and labile organic compounds in the gut of invertebrates. A striking consequence...

  14. Direct methane and nitrous oxide emissions of South African dairy ...

    African Journals Online (AJOL)

    South African Journal of Animal Science ... objective of this study was to estimate direct methane and nitrous oxide emissions of South African dairy and beef cattle in total and per province using the Tier 2 methodology of the Intergovernmental Panel on Climate Change (IPCC), but adapted for tropical production systems.

  15. Sources of nitrous oxide emitted from European forest soils

    DEFF Research Database (Denmark)

    Ambus, P.; Zechmeister-Boltenstern, S.; Butterbach-Bahl, K.

    2006-01-01

    Forest ecosystems may provide strong sources of nitrous oxide (N2O), which is important for atmospheric chemical and radiative properties. Nonetheless, our understanding of controls on forest N2O emissions is insufficient to narrow current flux estimates, which still are associated with great...

  16. Mitigation of nitrous oxide emissions from food production in China

    NARCIS (Netherlands)

    Ma, L.; Velthof, G.L.; Kroeze, C.; Ju, X.; Hu, C.; Oenema, O.; Zhang, F.

    2014-01-01

    We evaluate nitrogen (N) management options to mitigate nitrous oxide (N2O) emissions from food production in China. First, we review approaches to quantify N2O emissions. We argue that long-term monitoring of N2O measurements at different sites is needed to improve emission estimates. Next, past

  17. Nitrous-Oxide Emissions from Estuarine Intertidal Sediments

    NARCIS (Netherlands)

    Middelburg, J.J.; Klaver, G.; Nieuwenhuize, J.; Markusse, R.M.; Vlug, T.; Van der Nat, F.J.

    1995-01-01

    From September 1990 through December 1991 nitrous oxide flux measurements were made at 9 intertidal mud flat sites in the Scheldt Estuary. Nitrous oxide release rates were highly variable both between sites and over time at any one site. Annual nitrous oxide fluxes vary from about 10 mmol N m(-2) at

  18. 41 CFR 50-204.69 - Nitrous oxide.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Nitrous oxide. 50-204.69..., Vapors, Fumes, Dusts, and Mists § 50-204.69 Nitrous oxide. The piped systems for the in-plant transfer and distribution of nitrous oxide shall be designed, installed, maintained, and operated in accordance...

  19. Global oceanic production of nitrous oxide

    Science.gov (United States)

    Freing, Alina; Wallace, Douglas W. R.; Bange, Hermann W.

    2012-01-01

    We use transient time distributions calculated from tracer data together with in situ measurements of nitrous oxide (N2O) to estimate the concentration of biologically produced N2O and N2O production rates in the ocean on a global scale. Our approach to estimate the N2O production rates integrates the effects of potentially varying production and decomposition mechanisms along the transport path of a water mass. We estimate that the oceanic N2O production is dominated by nitrification with a contribution of only approximately 7 per cent by denitrification. This indicates that previously used approaches have overestimated the contribution by denitrification. Shelf areas may account for only a negligible fraction of the global production; however, estuarine sources and coastal upwelling of N2O are not taken into account in our study. The largest amount of subsurface N2O is produced in the upper 500 m of the water column. The estimated global annual subsurface N2O production ranges from 3.1 ± 0.9 to 3.4 ± 0.9 Tg N yr−1. This is in agreement with estimates of the global N2O emissions to the atmosphere and indicates that a N2O source in the mixed layer is unlikely. The potential future development of the oceanic N2O source in view of the ongoing changes of the ocean environment (deoxygenation, warming, eutrophication and acidification) is discussed. PMID:22451110

  20. Modelling nitrous oxide emissions from organic soils in Europe

    Science.gov (United States)

    Leppelt, Thomas; Dechow, Rene; Gebbert, Sören; Freibauer, Annette

    2013-04-01

    The greenhouse gas emission potential of peatland ecosystems are mandatory for a complete annual emission budget in Europe. The GHG-Europe project aims to improve the modelling capabilities for greenhouse gases, e.g., nitrous oxide. The heterogeneous and event driven fluxes of nitrous oxide are challenging to model on European scale, especially regarding the upscaling purpose and certain parameter estimations. Due to these challenges adequate techniques are needed to create a robust empirical model. Therefore a literature study of nitrous oxide fluxes from organic soils has been carried out. This database contains flux data from boreal and temperate climate zones and covers the different land use categories: cropland, grassland, forest, natural and peat extraction sites. Especially managed crop- and grassland sites feature high emission potential. Generally nitrous oxide emissions increases significantly with deep drainage and intensive application of nitrogen fertilisation. Whereas natural peatland sites with a near surface groundwater table can act as nitrous oxide sink. An empirical fuzzy logic model has been applied to predict annual nitrous oxide emissions from organic soils. The calibration results in two separate models with best model performances for bogs and fens, respectively. The derived parameter combinations of these models contain mean groundwater table, nitrogen fertilisation, annual precipitation, air temperature, carbon content and pH value. Influences of the calibrated parameters on nitrous oxide fluxes are verified by several studies in literature. The extrapolation potential has been tested by an implemented cross validation. Furthermore the parameter ranges of the calibrated models are compared to occurring values on European scale. This avoid unknown systematic errors for the regionalisation purpose. Additionally a sensitivity analysis specify the model behaviour for each alternating parameter. The upscaling process for European peatland

  1. Nitrous oxide emission from intensively managed grasslands

    NARCIS (Netherlands)

    Velthof, G.L.

    1997-01-01

    The aims of this thesis are to quantify nitrous oxide (N 2 O) emission from intensively managed grasslands in the Netherlands, to increase the insight in the factors controlling N 2 O emission from intensively managed grasslands and to explore

  2. Non-dispersive infrared nitrous oxide detector

    Energy Technology Data Exchange (ETDEWEB)

    Lessure, H.; Simizu, S.; Denes, L. [Carnegie Mellon Research Inst., Pittsburgh, PA (United States)

    1996-12-31

    Governmental guidelines are being established for monitoring the anesthetic gas nitrous oxide (N{sub 2}O) in hospitals, dentistry and veterinary practice to guard against deleterious effects on personnel in the workplace. Yet traditional equipment for monitoring N{sub 2}O was too expensive for continuous monitoring at low concentrations. Thus, there has been a pressing need to develop low-cost high-sensitivity instruments that could be used to continuously monitor nitrous oxide in the relevant working environments. A nitrous oxide detector has been developed which is capable of detecting concentrations as low as a few ppm nitrous oxide in the presence of large changing backgrounds of 0-1,500 ppm carbon dioxide and water vapor in the range of 30-70% RH at normal room temperatures. The detector utilizes three channels to measure the IR absorption due to the N{sub 2}O relative to the CO{sub 2} background and a reference channel. The prototype devices have an LCD readout for continuous display of the readings. Additional features include an analog output for remote data acquisition and audiovisual alerts for two threshold levels. Data will be presented to show the sensitivity and performance of the detector and discuss some of the issues related to bringing it from research to its current state as a pre-production prototype.

  3. Nitrous oxide-based techniques versus nitrous oxide-free techniques for general anaesthesia.

    Science.gov (United States)

    Sun, Rao; Jia, Wen Qin; Zhang, Peng; Yang, KeHu; Tian, Jin Hui; Ma, Bin; Liu, Yali; Jia, Run H; Luo, Xiao F; Kuriyama, Akira

    2015-11-06

    Nitrous oxide has been used for over 160 years for the induction and maintenance of general anaesthesia. It has been used as a sole agent but is most often employed as part of a technique using other anaesthetic gases, intravenous agents, or both. Its low tissue solubility (and therefore rapid kinetics), low cost, and low rate of cardiorespiratory complications have made nitrous oxide by far the most commonly used general anaesthetic. The accumulating evidence regarding adverse effects of nitrous oxide administration has led many anaesthetists to question its continued routine use in a variety of operating room settings. Adverse events may result from both the biological actions of nitrous oxide and the fact that to deliver an effective dose, nitrous oxide, which is a relatively weak anaesthetic agent, needs to be given in high concentrations that restrict oxygen delivery (for example, a common mixture is 30% oxygen with 70% nitrous oxide). As well as the risk of low blood oxygen levels, concerns have also been raised regarding the risk of compromising the immune system, impaired cognition, postoperative cardiovascular complications, bowel obstruction from distention, and possible respiratory compromise. To determine if nitrous oxide-based anaesthesia results in similar outcomes to nitrous oxide-free anaesthesia in adults undergoing surgery. We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014 Issue 10); MEDLINE (1966 to 17 October 2014); EMBASE (1974 to 17 October 2014); and ISI Web of Science (1974 to 17 October 2014). We also searched the reference lists of relevant articles, conference proceedings, and ongoing trials up to 17 October 2014 on specific websites (http://clinicaltrials.gov/, http://controlled-trials.com/, and http://www.centerwatch.com). We included randomized controlled trials (RCTs) comparing general anaesthesia where nitrous oxide was part of the anaesthetic technique used for the induction or maintenance of general

  4. Greenhouse effect due to atmospheric nitrous oxide

    Science.gov (United States)

    Yung, Y. L.; Wang, W. C.; Lacis, A. A.

    1976-01-01

    The greenhouse effect due to nitrous oxide in the present atmosphere is about 0.8 K. Increase in atmospheric N2O due to perturbation of the nitrogen cycle by man may lead to an increase in surface temperature as large as 0.5 K by 2025, or 1.0 K by 2100. Other climatic effects of N2O are briefly discussed.

  5. Synthesis of azoimidazolium dyes with nitrous oxide.

    Science.gov (United States)

    Tskhovrebov, Alexander G; Naested, Lara C E; Solari, Euro; Scopelliti, Rosario; Severin, Kay

    2015-01-19

    A new method for the synthesis of industrially important azoimidazolium dyes is presented. The procedure is based on a reagent which is rarely used in the context of synthetic organic chemistry: nitrous oxide ("laughing gas"). N2O is first coupled to N-heterocyclic carbenes. Subsequent reaction with aromatic compounds through an AlCl3-induced C-H activation process provides azoimidazolium dyes in good yields. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Nitrous oxide reduction by members of the family Rhodospirillaceae and the nitrous oxide reductase of Rhodopseudomonas capsulata.

    OpenAIRE

    McEwan, A G; Greenfield, A J; Wetzstein, H G; Jackson, J B; Ferguson, S J

    1985-01-01

    After growth in the absence of nitrogenous oxides under anaerobic phototrophic conditions, several strains of Rhodopseudomonas capsulata were shown to possess a nitrous oxide reductase activity. The enzyme responsible for this activity had a periplasmic location and resembled a nitrous oxide reductase purified from Pseudomonas perfectomarinus. Electron flow to nitrous oxide reductase was coupled to generation of a membrane potential and inhibited by rotenone but not antimycin. It is suggested...

  7. Nitrous oxide-induced vitamin B12 deficiency.

    Science.gov (United States)

    Stockton, Lindsey; Simonsen, Cameron; Seago, Susan

    2017-04-01

    Nitrous oxide is a gas that is odorless, colorless, and has a sweet taste at room temperature. Nitrous oxide has several uses, including in surgery and dentistry (referred to as "laughing gas"), in automotive racing, and in aerosol spray propellants. The aerosol spray propellants that typically use nitrous oxide are whipped cream canisters and cooking sprays. Unfortunately, these over-the-counter household items are a source of nitrous oxide that can be used for recreational use. The most popular is the use of industrial-grade canisters having the slang term "whippets." The nitrous oxide can be extracted by pushing the nozzle down slightly to the side and catching the released gas with a balloon. The contents of the balloon can then be directly inhaled, giving an instant feeling of euphoria. This is not a benign means to achieve a euphoric state but can cause severe nitrous oxide-induced B12 deficiency, which is presented in this case report.

  8. Does anaesthesia with nitrous oxide affect mortality or cardiovascular morbidity?

    DEFF Research Database (Denmark)

    Imberger, G; Orr, A; Thorlund, K

    2014-01-01

    BACKGROUND: /st> The role of nitrous oxide in modern anaesthetic practice is contentious. One concern is that exposure to nitrous oxide may increase the risk of cardiovascular complications. ENIGMA II is a large randomized clinical trial currently underway which is investigating nitrous oxide...... of these trials as having a low risk of bias. Using conventional meta-analysis, the relative risk of short-term mortality in the nitrous oxide group was 1.38 [95% confidence interval (CI) 0.22-8.71] and the relative risk of long-term mortality in the nitrous oxide group was 0.94 (95% CI 0.80-1.10). In both cases...... for how nitrous oxide used as part of general anaesthesia affects mortality and cardiovascular complications....

  9. Nitrous Oxide/Paraffin Hybrid Rocket Engines

    Science.gov (United States)

    Zubrin, Robert; Snyder, Gary

    2010-01-01

    Nitrous oxide/paraffin (N2OP) hybrid rocket engines have been invented as alternatives to other rocket engines especially those that burn granular, rubbery solid fuels consisting largely of hydroxyl- terminated polybutadiene (HTPB). Originally intended for use in launching spacecraft, these engines would also be suitable for terrestrial use in rocket-assisted takeoff of small airplanes. The main novel features of these engines are (1) the use of reinforced paraffin as the fuel and (2) the use of nitrous oxide as the oxidizer. Hybrid (solid-fuel/fluid-oxidizer) rocket engines offer advantages of safety and simplicity over fluid-bipropellant (fluid-fuel/fluid-oxidizer) rocket en - gines, but the thrusts of HTPB-based hybrid rocket engines are limited by the low regression rates of the fuel grains. Paraffin used as a solid fuel has a regression rate about 4 times that of HTPB, but pure paraffin fuel grains soften when heated; hence, paraffin fuel grains can, potentially, slump during firing. In a hybrid engine of the present type, the paraffin is molded into a 3-volume-percent graphite sponge or similar carbon matrix, which supports the paraffin against slumping during firing. In addition, because the carbon matrix material burns along with the paraffin, engine performance is not appreciably degraded by use of the matrix.

  10. Successful use of nitrous oxide during lumbar punctures: A call for nitrous oxide in pediatric oncology clinics.

    Science.gov (United States)

    Livingston, Mylynda; Lawell, Miranda; McAllister, Nancy

    2017-11-01

    Numerous reports describe the successful use of nitrous oxide for analgesia in children undergoing painful procedures. Although shown to be safe, effective, and economical, nitrous oxide use is not yet common in pediatric oncology clinics and few reports detail its effectiveness for children undergoing repeated lumbar punctures. We developed a nitrous oxide clinic, and undertook a review of pediatric oncology lumbar puncture records for those patients receiving nitrous oxide in 2011. No major complications were noted. Minor complications were noted in 2% of the procedures. We offer guidelines for establishing such a clinic. © 2017 Wiley Periodicals, Inc.

  11. Nitrous oxide emissions estimated with the Carbon Tracker Lagrange regional inversion framework suggest the North American source comes predominantly from agricultural regions

    Science.gov (United States)

    Nevison, C. D.; Andrews, A. E.; Thoning, K. W.; Saikawa, E.; Dlugokencky, E. J.; Sweeney, C.; Benmergui, J. S.

    2016-12-01

    The Carbon Tracker Lagrange (CTL) regional inversion framework is used to estimate North American nitrous oxide (N2O) emissions of 1.6 ± 0.4 Tg N/yr over 2008-2013. More than half of the North American emissions are estimated to come from the central agricultural belt, extending from southern Canada to Texas, and are strongest in spring and early summer, consistent with a nitrogen fertilizer-driven source. The estimated N2O flux from the Midwestern corn/soybean belt and the more northerly wheat belt corresponds to 5% of synthetic + organic N fertilizer applied to those regions. While earlier regional atmospheric inversion studies have suggested that global inventories such as EDGAR may be underestimating U.S. anthropogenic N2O emissions by a factor of 3 or more, our results, integrated over a full calendar year, are generally consistent with those inventories and with global inverse model results and budget constraints. The CTL framework is a Bayesian method based on footprints from the Stochastic Time-Inverted Lagrangian Transport (STILT) model applied to atmospheric N2O data from the National Oceanic and Atmospheric Administration (NOAA) Global Greenhouse Gas Reference Network, including surface, aircraft and tall tower platforms. The CTL inversion results are sensitive to the prescribed boundary condition or background value of N2O, which is estimated based on a new Empirical BackGround (EBG) product derived from STILT back trajectories applied to NOAA data. Analysis of the N2O EBG products suggests a significant, seasonally-varying influence on surface N2O data due to the stratospheric influx of N2O-depleted air. Figure 1. Posterior annual mean N2O emissions for 2010 estimated with the CTL regional inversion framework. The locations of NOAA surface and aircraft data used in the inversion are superimposed as black circles and grey triangles, respectively. Mobile surface sites are indicated with asterisks.

  12. Nitrous oxide-based versus nitrous oxide-free general anaesthesia and accidental awareness during general anaesthesia in surgical patients.

    Science.gov (United States)

    Hounsome, Juliet; Nicholson, Amanda; Greenhalgh, Janette; Cook, Tim M; Smith, Andrew F; Lewis, Sharon R

    2016-08-10

    Accidental awareness during general anaesthesia (AAGA) is when a patient unintentionally becomes conscious during a procedure performed with general anaesthesia and subsequently has explicit recall of this event. Incidence estimates for AAGA vary, with the most common estimate being one to two cases per 1000 general anaesthetics. Evidence linking nitrous oxide use and an increased risk of AAGA has come from observational studies data but the literature is contradictory, with some studies finding a protective effect of nitrous oxide. To assess the effect of general anaesthesia including nitrous oxide on the risk of AAGA in patients aged five years and over. We searched the following databases: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and trial registers ((www.clinicaltrials.gov), the WHO International Clinical Trials Registry Platform (www.who.int/ictrp/network/en/) and Current Controlled Trials (www.isrctn.com/)) for eligible studies on December 9 2015. In addition, we conducted forward and backward citation searching using key identified papers. We considered all randomized controlled trials (RCTs), including quasi-randomized studies and cluster-randomized studies, of participants aged five years or older receiving general anaesthesia for any type of surgery.We included trials in which participants receiving general anaesthesia that included nitrous oxide for maintenance at a concentration of at least 30% were compared with participants receiving no nitrous oxide during general anaesthesia. The intervention group must have received nitrous oxide in conjunction with an additional anaesthetic. We excluded studies where the depth of anaesthesia differed between the study arms. For inclusion in the review, studies needed to state in their methods that they planned to assess AAGA. We defined this as when a patient becomes conscious during a procedure performed with general anaesthesia and subsequently has explicit recall of this event

  13. Biochar and soil nitrous oxide emissions

    Directory of Open Access Journals (Sweden)

    Carlos Francisco Brazão Vieira Alho

    2012-05-01

    Full Text Available The objective of this work was to evaluate the effect of biochar application on soil nitrous oxide emissions. The experiment was carried out in pots under greenhouse conditions. Four levels of ground commercial charcoal of 2 mm (biochar were evaluated in a sandy Albaqualf (90% of sand: 0, 3, 6, and 9 Mg ha-1. All treatments received 100 kg ha-1 of N as urea. A cubic effect of biochar levels was observed on the N2O emissions. Biochar doses above 5 Mg ha-1 started to mitigate the emissions in the evaluated soil. However, lower doses promote the emissions.

  14. Improved measurements of atmospheric nitrous oxide

    Science.gov (United States)

    Wendel, JoAnna

    2014-10-01

    Nitrous oxide (N2O), one of the main greenhouse gases, is known for its degrading effect on Earth's ozone layer. The gas is created naturally by microbial activity on land and in the oceans and artificially by emissions from human-made processes, through fertilization or burning fossil fuels. As the climate continues to warm, it has become imperative to be able to track and quantify the greenhouse gas content of the atmosphere, and various satellite missions have been launched to do so.

  15. Nitrous Oxide Emission by Aquatic Macrofauna

    DEFF Research Database (Denmark)

    Stief, Peter; Nielsen, Lars Peter; Schramm, Andreas

    not ingest large quantities of microorganisms produced insignificant amounts of nitrous oxide. With increasing eutrophication, filter- and deposit-feeders often become the dominant feeding guilds of benthic communities. Thus, with increasing nitrate pollution, aquatic macrofauna has the potential to further......Many macrofauna species co-ingest large quantities of microorganisms some of which survive the gut passage. Denitrifying bacteria, in particular, become metabolically induced by anoxic conditions, nitrate, and labile organic compounds in the gut of invertebrates. A striking consequence of the short...

  16. Catalytic abatement of nitrous oxide from nitric and production

    NARCIS (Netherlands)

    Oonk, J.

    1998-01-01

    Nitric acid production is identified as a main source of nitrous oxide. Options for emission reduction however are not available. TNO and Hydro Agri studied the technological and economic feasibility of catalytic decomposition of nitrous oxide in nitric acid tail-gases. Although in literature

  17. Nitrous oxide emission from soils amended with crop residues

    NARCIS (Netherlands)

    Velthof, G.L.; Kuikman, P.J.; Oenema, O.

    2002-01-01

    Crop residues incorporated in soil are a potentially important source of nitrous oxide (N2O), though poorly quantified. Here, we report on the N2O emission from 10 crop residues added to a sandy and a clay soil, both with and without additional nitrate (NO3-). In the sandy soil, total nitrous oxide

  18. Early misconceptions about nitrous oxide, an "invigorating" asphyxiant.

    Science.gov (United States)

    Alston, Theodore A

    2010-02-01

    Well into the twentieth century, nitrous oxide was often suspected to support life in the manner of oxygen. Authorities contributing to that life-threatening misimpression include Humphry Davy, Gardner Q. Colton, and George W. Crile. Concomitantly, deprivation of oxygen was long touted as a requisite for nitrous oxide anesthesia.

  19. Nitrous oxide emission as affected by tillage practices and fertilizer application

    Energy Technology Data Exchange (ETDEWEB)

    Hao, X.; Chang, C.; Travis, G. [Agriculture and Agri-Food Canada, Lethbridge Research Centre, Lethbridge, AB (Canada)

    1999-07-01

    Farmland emission of nitrous oxide is a concern to both environmental and agricultural production, and field experiments were carried out in order to investigate N(2)O loss as affected by rates and times of fertilizer application and straw/tillage practices under irrigated fields in southern Alberta. With the maximum occurring in March-April, the nitrous oxide flux varied greatly during the year, and there was a significant flux of nitrous oxide in the winter months, associated with freeze-thaw events. Nitrous oxide emission, in general, increases with excess fertilization and the emission is greater with fall than with spring application. Nitrous oxide emission was reduced because of straw removal when there was no fertilizer, but it increased emission when 100 kg N/ha fertilizer was used. Fall ploughing increased nitrous ozide emission, and to minimize the emission of the gas, farmers should apply N fertilizer in the spring, at no more than the recommended rate, keep the straw on the field, and plough the field only in the spring. Estimating the amount of nitrous oxide emission produced based on the amount of N fertilizer used may be a very inaccurate means. (Abstract only)

  20. Laryngospasm With Apparent Aspiration During Sedation With Nitrous Oxide.

    Science.gov (United States)

    Babl, Franz E; Grindlay, Joanne; Barrett, Michael Joseph

    2015-11-01

    Nitrous oxide and oxygen mixture has become increasingly popular for the procedural sedation and analgesia of children in the emergency department. In general, nitrous oxide is regarded as a very safe agent according to large case series. We report a case of single-agent nitrous oxide sedation of a child, complicated by laryngospasm and radiographically confirmed bilateral upper lobe pulmonary opacities. Although rarely reported with parenteral sedative agents, laryngospasm and apparent aspiration has not been previously reported in isolated nitrous oxide sedation. This case highlights that, similar to other sedative agents, nitrous oxide administration also needs to be conducted by staff and in settings in which airway emergencies can be appropriately managed. Copyright © 2015 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

  1. 78 FR 6400 - Results of FAA Nitrous Oxide BLEVE Characterization Testing

    Science.gov (United States)

    2013-01-30

    ... Federal Aviation Administration Results of FAA Nitrous Oxide BLEVE Characterization Testing AGENCY... nitrous oxide (N 2 O) characteristics. Nitrous oxide is an important oxidizer to developers of some commercial reusable launch vehicles. A potential hazard in nitrous oxide storage and handling is a Boiling...

  2. Dose-response and concentration-response relation of rocuronium infusion during propofol nitrous oxide and isoflurane nitrous oxide anaesthesia

    NARCIS (Netherlands)

    Kansanaho, M; Olkkola, KT; Wierda, JMKH

    The dose-response and concentration-response relation of rocuronium infusion was studied in 20 adult surgical patients during proporfol-nitrous oxide and isoflurane (1 MAC) -nitrous oxide anaesthesia. Neuromuscular block was kept constant, initially at 90% and then at 50% with a closed-loop feedback

  3. Current use of nitrous oxide in public hospitals in Scandinavian countries

    DEFF Research Database (Denmark)

    Husum, Bent; Stenqvist, O; Alahuhta, S

    2013-01-01

    The use of nitrous oxide in modern anaesthesia has been questioned. We surveyed changes in use of nitrous oxide in Scandinavia and its justifications during the last two decades.......The use of nitrous oxide in modern anaesthesia has been questioned. We surveyed changes in use of nitrous oxide in Scandinavia and its justifications during the last two decades....

  4. Nitrous oxide-induced slow and delta oscillations.

    Science.gov (United States)

    Pavone, Kara J; Akeju, Oluwaseun; Sampson, Aaron L; Ling, Kelly; Purdon, Patrick L; Brown, Emery N

    2016-01-01

    Switching from maintenance of general anesthesia with an ether anesthetic to maintenance with high-dose (concentration >50% and total gas flow rate >4 liters per minute) nitrous oxide is a common practice used to facilitate emergence from general anesthesia. The transition from the ether anesthetic to nitrous oxide is associated with a switch in the putative mechanisms and sites of anesthetic action. We investigated whether there is an electroencephalogram (EEG) marker of this transition. We retrospectively studied the ether anesthetic to nitrous oxide transition in 19 patients with EEG monitoring receiving general anesthesia using the ether anesthetic sevoflurane combined with oxygen and air. Following the transition to nitrous oxide, the alpha (8-12 Hz) oscillations associated with sevoflurane dissipated within 3-12 min (median 6 min) and were replaced by highly coherent large-amplitude slow-delta (0.1-4 Hz) oscillations that persisted for 2-12 min (median 3 min). Administration of high-dose nitrous oxide is associated with transient, large amplitude slow-delta oscillations. We postulate that these slow-delta oscillations may result from nitrous oxide-induced blockade of major excitatory inputs (NMDA glutamate projections) from the brainstem (parabrachial nucleus and medial pontine reticular formation) to the thalamus and cortex. This EEG signature of high-dose nitrous oxide may offer new insights into brain states during general anesthesia. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  5. Explosion characteristics of flammable organic vapors in nitrous oxide atmosphere.

    Science.gov (United States)

    Koshiba, Yusuke; Takigawa, Tomihisa; Matsuoka, Yusaku; Ohtani, Hideo

    2010-11-15

    Despite unexpected explosion accidents caused by nitrous oxide have occurred, few systematic studies have been reported on explosion characteristics of flammable gases in nitrous oxide atmosphere compared to those in air or oxygen. The objective of this paper is to characterize explosion properties of mixtures of n-pentane, diethyl ether, diethylamine, or n-butyraldehyde with nitrous oxide and nitrogen using three parameters: explosion limit, peak explosion pressure, and time to the peak explosion pressure. Then, similar mixtures of n-pentane, diethyl ether, diethylamine, or n-butyraldehyde with oxygen and nitrogen were prepared to compare their explosion characteristics with the mixtures containing nitrous oxide. The explosion experiments were performed in a cylindrical vessel at atmospheric pressure and room temperature. The measurements showed that explosion ranges of the mixtures containing nitrous oxide were narrow compared to those of the mixtures containing oxygen. On the other hand, the maximum explosion pressures of the mixtures containing nitrous oxide were higher than those of the mixtures containing oxygen. Moreover, our experiments revealed that these mixtures differed in equivalence ratios at which the maximum explosion pressures were observed: the pressures of the mixtures containing nitrous oxide were observed at stoichiometry; in contrast, those of the mixtures containing oxygen were found at fuel-rich area. Chemical equilibrium calculations confirmed these behaviors. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. The hematological effects of nitrous oxide anesthesia in pediatric patients.

    Science.gov (United States)

    Duma, Andreas; Cartmill, Christopher; Blood, Jane; Sharma, Anshuman; Kharasch, Evan D; Nagele, Peter

    2015-06-01

    Prolonged administration of nitrous oxide causes an increase in plasma homocysteine in children via vitamin B12 inactivation. However, it is unclear whether nitrous oxide doses used in clinical practice cause adverse hematological effects in pediatric patients. This retrospective study included 54 pediatric patients undergoing elective spinal surgery: 41 received nitrous oxide throughout anesthesia (maintenance group), 9 received nitrous oxide for induction and/or emergence (induction/emergence group), and 4 did not receive nitrous oxide (nitrous oxide-free group). Complete blood counts obtained before and up to 4 days after surgery were assessed for anemia, macrocytosis/microcytosis, anisocytosis, hyperchromatosis/hypochromatosis, thrombocytopenia, and leukopenia. The change (Δ) from preoperative to the highest postoperative value was calculated for mean corpuscular volume (MCV) and red cell distribution width (RDW). No pancytopenia was present in any patient after surgery. All patients had postoperative anemia, and none had macrocytosis. Postoperative MCV (mean [99% confidence interval]) peaked at 86 fL (85-88 fL), 85 fL (81-89 fL), and 88 fL (80-96 fL) and postoperative RDW at 13.2% (12.8-13.5%), 13.3% (12.7-13.8%), and 13.0% (11.4-14.6%) for the maintenance group, the induction/emergence group, and the nitrous oxide-free group. Two patients in the maintenance group (5%) developed anisocytosis (RDW >14.6%), but none in the induction/emergence group or in the nitrous oxide-free group (P = 0.43). Both ΔMCV (P = 0.52) and ΔRDW (P = 0.16) were similar across all groups. Nitrous oxide exposure for up to 8 hours is not associated with megaloblastic anemia in pediatric patients undergoing major spinal surgery.

  7. Dentists' and Parents' Attitude Toward Nitrous Oxide Use in Kuwait.

    Science.gov (United States)

    Alkandari, Sarah A; Almousa, Fatemah; Abdulwahab, Mohammad; Boynes, Sean G

    2016-01-01

    The aim of this study was to investigate the attitude of dentists in Kuwait toward the use of nitrous oxide sedation as a behavior management technique (BMT) for pediatric patients and assess their training in nitrous oxide sedation. In addition, we assessed parents' knowledge of and attitude toward the use of nitrous oxide as a BMT for their children. The objective was to determine if nitrous oxide sedation is being provided and utilized as a means to enhance dental care for pediatric patients. A cross-sectional survey was randomly distributed to both groups of interest: parents accompanying their children to the dentist and licensed dentists in Kuwait. Participants had to meet certain inclusion criteria to be included in the survey and had to complete the entire questionnaire to be part of the analysis. A total of 381 parents completed the questionnaires. The majority of parents responded that they were unaware of nitrous oxide sedation and were not aware of it as a BMT (79%). Two thirds of the parent would accept nitrous oxide sedation if recommended by a dentist treating their children. Two hundred and one dentists completed the survey and met the inclusion criteria. The majority (74.5%) of dentists were willing to use nitrous oxide as a BMT. However, only 6% were utilizing nitrous oxide sedation and providing it to their child patient if indicated. The main reasons for this huge gap are lack of facilities/equipment and lack of training as indicated by the dentists. This study showed that parents are accepting nitrous oxide sedation as a BMT for their children. It also showed the willingness of the dentists to provide such BMT to their patients. The lack of training and lack of equipment are the main barriers to providing such service to the patients. More training courses and more facilities should be provided to eliminate such barriers.

  8. Should Nitrous Oxide Be Used for Laboring Patients?

    Science.gov (United States)

    Richardson, Michael G; Lopez, Brandon M; Baysinger, Curtis L

    2017-03-01

    Nitrous oxide, long used during labor in Europe, is gaining popularity in the United States. It offers many beneficial attributes, with few drawbacks. Cost, safety, and side effect profiles are favorable. Analgesic effectiveness is highly variable, yet maternal satisfaction is often high among the women who choose to use it. Despite being less effective in treating labor pain than neuraxial analgesic modalities, nitrous oxide serves the needs and preferences of a subset of laboring parturients. Nitrous oxide should, therefore, be considered for inclusion in the repertoire of modalities used to alleviate pain and facilitate effective coping during labor. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Nitrous oxide induced myeloneuropathy: a case report.

    Science.gov (United States)

    Rheinboldt, Matt; Harper, Derrick; Parrish, David; Francis, Kirenza; Blase, John

    2014-02-01

    We report the case of a 35-year-old male with a history of chronic, escalating nitrous oxide abuse who presented to the ER with a history of recent onset generalized weakness, altered sensorium, abnormal posturing of the hands, urinary complaints, and decreased balance. Physical examination was notable for pathologically brisk reflexes in all extremities, generalized flexion contracture of the fingers, decreased sensation in a stocking and glove distribution, and a weakly positive Babinski sign. The patient was noted to be a poor historian with decreased attention and concentration though otherwise generally alert and oriented. No discrete sensory level in the chest or trunk was detected, and the overall clinical appearance was felt to be most compatible with a mixed myeloneuropathic pattern of central and peripheral involvement. Laboratory findings were normal and noncontributory. Cervical spine MRI subsequently performed to rule out cord compression, intrinsic spinal cord mass, or demyelinating disease was notable for a long segment of increased T2 signal extending from C2-C3 to C6-C7 localizing to the dorsal columns of the cord in a typical "inverted V" fashion. No associated cord expansion was seen nor was there evidence of extrinsic compression; faint associated contrast enhancement was observed on post-gadolinium images. Further evaluation with nerve conduction velocity and electromyographic testing was deferred. Based on the exam findings, clinical history, and presentation, a diagnosis of nitrous oxide-related myeloneuropathy was made, and treatment with high-dose vitamin B12 supplementation was instituted. Recovery has been slow to date.

  10. Recreational nitrous oxide use: Prevalence and risks.

    Science.gov (United States)

    van Amsterdam, Jan; Nabben, Ton; van den Brink, Wim

    2015-12-01

    Nitrous oxide (N2O; laughing gas) is clinically used as a safe anesthetic (dentistry, ambulance, childbirth) and appreciated for its anti-anxiety effect. Since five years, recreational use of N2O is rapidly increasing especially in the dance and festival scene. In the UK, N2O is the second most popular recreational drug after cannabis. In most countries, nitrous oxide is a legal drug that is widely available and cheap. Last month prevalence of use among clubbers and ravers ranges between 40 and almost 80 percent. Following one inhalation, mostly from a balloon, a euphoric, pleasant, joyful, empathogenic and sometimes hallucinogenic effect is rapidly induced (within 10 s) and disappears within some minutes. Recreational N2O use is generally moderate with most users taking less than 10 balloons of N2O per episode and about 80% of the users having less than 10 episodes per year. Side effects of N2O include transient dizziness, dissociation, disorientation, loss of balance, impaired memory and cognition, and weakness in the legs. When intoxicated accidents like tripping and falling may occur. Some fatal accidents have been reported due to due to asphyxia (hypoxia). Heavy or sustained use of N2O inactivates vitamin B12, resulting in a functional vitamin B12 deficiency and initially causing numbness in fingers, which may further progress to peripheral neuropathy and megaloblastic anemia. N2O use does not seem to result in dependence. Considering the generally modest use of N2O and its relative safety, it is not necessary to take legal measures. However, (potential) users should be informed about the risk of vitamin B12-deficiency related neurological and hematological effects associated with heavy use. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Nitrous oxide emissions from wastewater treatment processes

    Science.gov (United States)

    Law, Yingyu; Ye, Liu; Pan, Yuting; Yuan, Zhiguo

    2012-01-01

    Nitrous oxide (N2O) emissions from wastewater treatment plants vary substantially between plants, ranging from negligible to substantial (a few per cent of the total nitrogen load), probably because of different designs and operational conditions. In general, plants that achieve high levels of nitrogen removal emit less N2O, indicating that no compromise is required between high water quality and lower N2O emissions. N2O emissions primarily occur in aerated zones/compartments/periods owing to active stripping, and ammonia-oxidizing bacteria, rather than heterotrophic denitrifiers, are the main contributors. However, the detailed mechanisms remain to be fully elucidated, despite strong evidence suggesting that both nitrifier denitrification and the chemical breakdown of intermediates of hydroxylamine oxidation are probably involved. With increased understanding of the fundamental reactions responsible for N2O production in wastewater treatment systems and the conditions that stimulate their occurrence, reduction of N2O emissions from wastewater treatment systems through improved plant design and operation will be achieved in the near future. PMID:22451112

  12. Complexation of Nitrous Oxide by Frustrated Lewis Pairs

    NARCIS (Netherlands)

    Otten, Edwin; Neu, Rebecca C.; Stephan, Douglas W.

    2009-01-01

    Frustrated Lewis pairs comprised of a basic yet sterically encumbered phosphine with boron Lewis acids bind nitrous oxide to give intact PNNOB linkages. The synthesis, structure, and bonding of these species are described.

  13. Nitrous Oxide Liquid Injection Thrust Vector Control System Testing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A Nitrous Oxide-fed Liquid Thrust Vector Control system is proposed as an efficient method for vehicle attitude control during powered flight. Pulled from a N2O main...

  14. Miniature Nontoxic Nitrous Oxide-Propane (MINNOP) Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop the Miniature Nontoxic Nitrous Oxide-Propane (MINNOP) propulsion system, a small bipropellant propulsion system which we offer as an...

  15. Toxicity of bone marrow in dentists exposed to nitrous oxide.

    OpenAIRE

    Sweeney, B; Bingham, R M; Amos, R J; Petty, A C; Cole, P V

    1985-01-01

    The morphology of the bone marrow of 21 dentists who habitually used nitrous oxide in their surgeries was investigated. Exposure to nitrous oxide was measured with an atmospheric sampling device, and each dentist was invited to fill in a questionnaire giving details of medical history, diet, and intake of alcohol. During the trial a full neurological and haematological investigation was carried out and a bone marrow aspirate was examined both morphologically and by the deoxyuridine suppressio...

  16. Trace nitrous oxide levels in the postanesthesia care unit.

    Science.gov (United States)

    McGregor, D G; Senjem, D H; Mazze, R I

    1999-08-01

    The effect of trace levels of waste anesthetic gases on the health of postanesthesia care unit (PACU) nurses who work in an unscavenged environment has been questioned, although it seems likely that levels of trace gases in the PACU would be much lower than those in the operating room. In this study, we documented nitrous oxide levels in the ambient air of two large PACUs. Nitrous oxide levels were measured using a time-weighted average monitor worn by 33 PACU workers at two different hospitals for the duration of their shifts. On the same day, patient data were collected at the time of admission to the PACU. Data included age and weight of the patient, type of surgery, anesthetic technique, and end-tidal level of nitrous oxide immediately before the patient left the operating room. The mean time-weighted average nitrous oxide level in PACU A was 2.0 ppm (range 0-6.4); in PACU B, it was undetectable, i.e., < 2.0 ppm. Levels of nitrous oxide to which PACU patient care personnel are exposed are well below the National Institute of Occupational Safety and Health and Occupational Health and Safety Administration recommended exposure level of 25 ppm measured for the duration of anesthetic administration. Our results indicate that the levels of nitrous oxide in postanesthesia care units with well maintained, modern ventilation systems are very low. Previous research suggests that the health of workers exposed to these levels should not be adversely affected.

  17. Top-down model estimates, bottom-up inventories, and future projections of global natural and anthropogenic emissions of nitrous oxide

    Science.gov (United States)

    Davidson, E. A.; Kanter, D.

    2013-12-01

    Nitrous oxide (N2O) is the third most abundantly emitted greenhouse gas and the largest remaining emitted ozone depleting substance. It is a product of nitrifying and denitrifying bacteria in soils, sediments and water bodies. Humans began to disrupt the N cycle in the preindustrial era as they expanded agricultural land, used fire for land clearing and management, and cultivated leguminous crops that carry out biological N fixation. This disruption accelerated after the industrial revolution, especially as the use of synthetic N fertilizers became common after 1950. Here we present findings from a new United Nations Environment Programme report, in which we constrain estimates of the anthropogenic and natural emissions of N2O and consider scenarios for future emissions. Inventory-based estimates of natural emissions from terrestrial, marine and atmospheric sources range from 10 to 12 Tg N2O-N/yr. Similar values can be derived for global N2O emissions that were predominantly natural before the industrial revolution. While there was inter-decadal variability, there was little or no consistent trend in atmospheric N2O concentrations between 1730 and 1850, allowing us to assume near steady state. Assuming an atmospheric lifetime of 120 years, the 'top-down' estimate of pre-industrial emissions of 11 Tg N2O-N/yr is consistent with the bottom-up inventories for natural emissions, although the former includes some modest pre-industrial anthropogenic effects (probably period 2000-2007. Based on a review of bottom-up inventories, we estimate total net anthropogenic N2O emissions of 6.0 Tg N2O-N/yr (5.4-8.4 Tg N2O-N/yr). Estimates (and ranges) by sector (in Tg N2O-N/yr) are: agriculture 4.1 Tg (3.8-6.8); biomass burning 0.7 (0.5-1.7); energy and transport 0.7 (0.5-1.2); industry 0.7 (0.3-1.1); and other 0.5 (0.2 - 0.8). Tropical deforestation has reduced emissions by 0.7 (0.5 - 1.0). Given the large inherent uncertainties in both approaches, it is encouraging that the

  18. Catalytic decomposition of nitrous oxide monopropellant for hybrid motor ignition

    Science.gov (United States)

    Wilson, Matthew

    Nitrous oxide (N2O) is an inexpensive and readily available non-toxic rocket motor oxidizer. It is the most commonly used oxidizer for hybrid bipropellant rocket systems, and several bipropellant liquid rocket designs have also used nitrous oxide. In liquid form, N2O is highly stable, but in vapor form it has the potential to decompose exothermically, releasing up to 1865 Joules per gram of vapor as it dissociates into nitrogen and oxygen. Consequently, it has long been considered as a potential "green" replacement for existing highly toxic and dangerous monopropellants. This project investigates the feasibility of using the nitrous oxide decomposition reaction as a monopropellant energy source for igniting liquid bipropellant and hybrid rockets that already use nitrous oxide as the primary oxidizer. Because nitrous oxide is such a stable propellant, the energy barrier to dissociation is quite high; normal thermal decomposition of the vapor phase does not occur until temperatures are above 800 C. The use of a ruthenium catalyst decreases the activation energy for this reaction to allow rapid decomposition below 400 C. This research investigates the design for a prototype device that channels the energy of dissociation to ignite a laboratory scale hybrid rocket motor.

  19. Technical opportunities to reduce global anthropogenic emissions of nitrous oxide

    Science.gov (United States)

    Winiwarter, Wilfried; Höglund-Isaksson, Lena; Klimont, Zbigniew; Schöpp, Wolfgang; Amann, Markus

    2018-01-01

    We describe a consistent framework developed to quantify current and future anthropogenic emissions of nitrous oxide and the available technical abatement options by source sector for 172 regions globally. About 65% of the current emissions derive from agricultural soils, 8% from waste, and 4% from the chemical industry. Low-cost abatement options are available in industry, wastewater, and agriculture, where they are limited to large industrial farms. We estimate that by 2030, emissions can be reduced by about 6% ±2% applying abatement options at a cost lower than 10 €/t CO2-eq. The largest abatement potential at higher marginal costs is available from agricultural soils, employing precision fertilizer application technology as well as chemical treatment of fertilizers to suppress conversion processes in soil (nitrification inhibitors). At marginal costs of up to 100 €/t CO2-eq, about 18% ±6% of baseline emissions can be removed and when considering all available options, the global abatement potential increases to about 26% ±9%. Due to expected future increase in activities driving nitrous oxide emissions, the limited technical abatement potential available means that even at full implementation of reduction measures by 2030, global emissions can be at most stabilized at the pre-2010 level. In order to achieve deeper reductions in emissions, considerable technological development will be required as well as non-technical options like adjusting human diets towards moderate animal protein consumption.

  20. Nitrous Oxide Anesthesia and Plasma Homocysteine in Adolescents

    Science.gov (United States)

    Nagele, Peter; Tallchief, Danielle; Blood, Jane; Sharma, Anshuman; Kharasch, Evan D.

    2011-01-01

    Background Nitrous oxide inactivates vitamin B12, inhibits methionine synthase and consequently increases plasma total homocysteine (tHcy). Prolonged exposure to nitrous oxide can lead to neuropathy, spinal cord degeneration and even death in children. We tested the hypothesis that nitrous oxide anesthesia causes a significant increase in plasma tHcy in children. Methods Twenty-seven children (age 10-18 years) undergoing elective major spine surgery were enrolled and serial plasma samples from 0 – 96 hours after induction were obtained. The anesthetic regimen, including the use of nitrous oxide, was at the discretion of the anesthesiologist. Plasma tHcy was measured using standard enzymatic assays. Results The median baseline plasma tHcy concentration was 5.1 μmol/L (3.9 – 8.0 μmol/L, interquartile range) and increased in all patients exposed to nitrous oxide (n=26) by an average of +9.4 μmol/L (geometric mean; 95% CI 7.1 – 12.5 μmol/L) or +228% (mean; 95% CI 178% - 279%). Plasma tHcy peaked between 6-8 hours after induction of anesthesia. One patient who did not receive nitrous oxide had no increase in plasma tHcy. Several patients experienced a several-fold increase in plasma tHcy (max. +567%). The increase in plasma tHcy was strongly correlated with the duration and average concentration of nitrous oxide anesthesia (r= 0.80; pnitrous oxide anesthesia develop significantly increased plasma tHcy concentrations. The magnitude of this effect appears to be greater compared to adults; however, the clinical relevance is unknown. PMID:21680854

  1. A comparison of the analgesic effects of methoxyflurane-nitrous oxide and nitrous oxide alone during labour related to the Eysenck personality inventory test.

    Science.gov (United States)

    Arozenius, S; Dahlgren, B E; Lindwall, L; Akerlind, I

    1980-01-01

    One hundred and thirty-three paturients who had received either methoxyflurane-nitrous oxide or nitrous oxide analgesia with or without pudendal block, underwent the Eysenck Personality Inventory Test on the second postpartum day and evaluated their memory of the pain (Subjectively Evaluated Pain Suffering Scores) during labor. Parturients who had received methoxyflurance-nitrous oxide analgesia reported significantly lower pain suffering than parturients who had had nitrous oxide analgesia. Subdivision according to Personality Inventory factors showed that at the introvert end of the Extroversion-Introversion scale, methoxyflurance-nitrous oxide analgesia with or without additional pudendal block resulted in significantly lower pain suffering than did not nitrous oxide analgesia. On the other hand, nitrous oxide analgesia without additional pudendal block gave significantly lower pain suffering at the extrovert end of the scale. Among the extroverts there was a tendency, though not statistically significant, towards non-approval of the pudendal block.

  2. Sources of methane and nitrous oxide in California's Central Valley estimated through direct airborne flux and positive matrix factorization source apportionment of groundbased and regional tall tower measurements

    Science.gov (United States)

    Guha, Abhinav

    covariance enables quantification of emissions from those area sources that are largely composed of arbitrarily located minor point sources (e.g. dairies and oil fields). The top-down analysis provides confirmation of the dominance of dairy and livestock source for methane emissions in California. Minor but significant contributions to methane emissions are observed from oil and gas extraction, rice cultivation and wetlands; the estimates for these sectors being either negligible (e.g. wetlands) or highly uncertain (e.g. oil and gas extraction) in the statewide inventories and probably underestimated as a proportion of the total inventory. The top-down analysis also confirms agricultural soil management and dairy and livestock as the two principal sources of N2O consistent with the inventory, but shows that N2O contributions attributed to the transportation sector are overestimated in the statewide inventory. These new top down constraints should be used to correct these errors in the current bottom-up inventory, which is a critical step for future assessments of the efficacy of emission reduction regulations. Particularly, measurement techniques like vehicle dynamometer emission calculations (for transportation sources), source-specific short range ground-based inverse dispersion (for dairy and livestock sources), airborne eddy covariance and airborne mass balance approach based emissions estimation (over oil and gas fields) and ground based eddy-covariance (for wetlands and agriculture sector) can be used effectively to generate direct emissions estimates for methane and nitrous oxide that help update and improve the accuracy of the state inventory.

  3. Psychedelic effects of a subanesthetic concentration of nitrous oxide.

    Science.gov (United States)

    Block, R. I.; Ghoneim, M. M.; Kumar, V.; Pathak, D.

    1990-01-01

    The subjective effects of nitrous oxide were examined by administering questionnaires to volunteers (16 men and 16 women) breathing 30% nitrous oxide or 100% oxygen. Nitrous oxide produced a variety of subjective effects, including some that are characteristic of psychedelic drugs, such as happy, euphoric mood changes, changes in body awareness and image, alterations of time perception, and experiences of a dreamy, detached reverie state. The subjective effects, including those of a psychedelic nature, were very similar to the subject effects we observed in a previous study of nitrous oxide. However, euphoric mood changes were more pronounced, and adverse effects were less pronounced, in the present study, possibly due to the shorter duration of gas inhalation or the minimal tests of performance involved. Some other differences in subjective effects between the present and previous studies were identified by a discriminant analysis and seemed related to specific differences in experimental conditions. This suggests that the environment can influence which drug effects emerge, or at least their relative prominence. Clinicians should be familiar with the range of subjective effects that patients inhaling nitrous oxide may experience. PMID:2097905

  4. Whippits, nitrous oxide and the dangers of legal highs.

    Science.gov (United States)

    Thompson, Alexander G; Leite, M Isabel; Lunn, Michael P; Bennett, David L H

    2015-06-01

    Nitrous oxide is increasingly being used as a recreational drug. Prolonged use of nitrous oxide can have disabling neurological sequelae due to functional inactivation of vitamin B₁₂. We present three cases illustrating the neurological complications of using nitrous oxide. Two of these patients received nitrous oxide as a consequence of repeated hospital attendance and the third via 'Whippit' canisters used in cream dispensers, which are now widely available. Two patients developed sensorimotor peripheral neuropathy with demyelinating features with no clinical or imaging evidence of myelopathy, emphasising that not all patients develop subacute combined degeneration of the spinal cord (the typical presentation of functional vitamin B12 deficiency). The diagnosis was based upon the history of nitrous oxide use and raised levels of homocysteine and/or methylmalonic acid. All patients were treated with parenteral vitamin B12 with partial recovery, though two were left significantly disabled. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  5. Nitrous oxide flux and nitrogen transformations across a landscape gradient in Amazonia

    Science.gov (United States)

    Livingston, Gerald P.; Vitousek, Peter M.; Matson, Pamela A.

    1988-01-01

    Nitrous oxide flux and nitrogen turnover were measured in three types of Amazonian forest ecosystems within Reserva Florestal Ducke near Manaus, Brazil. Nitrogen mineralization and nitrate production measured during 10-day laboratory incubations were 3-4 times higher in clay soils associated with 'terra firme' forests on ridge-top and slope positions than in 'campinarana' forests on bottomland sand soils. In contrast, nitrous oxide fluxes did not differ significantly among sites, but were highly variable in space and time. The observed frequency distribution of flux was positively skewed, with a mean overall sites and all sampling times of 1.3 ng N2O-N/sq cm per hr. Overall, the flux estimates were comparable to or greater than those of temperature forests, but less than others reported for Amazoonia. Results from a field fertilization experiment suggest that most nitrous oxide flux was associated with denitrification of soil nitrate.

  6. Time-weighted averaging for nitrous oxide: an automated method.

    Science.gov (United States)

    McGill, W A; Rivera, O; Howard, R

    1980-11-01

    An automated method of obtaining a time-weighted average of nitrous oxide levels in an operating room was compared with a standard method. The automated method consisted of electronic integration of the voltage output of a nitrous oxide analyzer using a multimeter-microprocessor. The standard method utilized a bag and pump to collect a room air sample, which was subsequently analyzed with a nitrous oxide analyzer. There was a high degree of correlation (r = 0.99) between the two methods. It is concluded that the automated method is an accurate alternative and offers institutions a simple, cost-effective method of monitoring and documenting results of pollution control programs in anesthetizing locations.

  7. Nitrous Oxide Emissions from a Large, Impounded River: The Ohio River

    Science.gov (United States)

    Models suggest that microbial activity in streams and rivers is a globally significant source of anthropogenic nitrous oxide (N2O), a potent greenhouse gas and the leading cause of stratospheric ozone destruction. However, model estimates of N2O emissions are poorly constrained ...

  8. Marine nitrous oxide emissions: An unknown liability for the international water sector

    Science.gov (United States)

    Reliable estimates of anthropogenic greenhouse gas (GHG) emissions are essential for setting effective climate policy at both the sector and national level. Current IPCC Guidelines for calculating nitrous oxide (N2O) emissions from sewage management are both highly uncertain and ...

  9. Designing efficient nitrous oxide sampling strategies in agroecosystems using simulation models

    Science.gov (United States)

    Debasish Saha; Armen R. Kemanian; Benjamin M. Rau; Paul R. Adler; Felipe Montes

    2017-01-01

    Annual cumulative soil nitrous oxide (N2O) emissions calculated from discrete chamber-based flux measurements have unknown uncertainty. We used outputs from simulations obtained with an agroecosystem model to design sampling strategies that yield accurate cumulative N2O flux estimates with a known uncertainty level. Daily soil N2O fluxes were simulated for Ames, IA (...

  10. Controls on nitrous oxide production and consumption in reservoirs of the Ohio River Basin

    Science.gov (United States)

    Aquatic ecosystems are a globally significant source of nitrous oxide (N2O), a potent greenhouse gas, but estimates are largely based on studies conducted in streams and rivers with relatively less known about N2O dynamics in lakes and reservoirs. Due to long water residence tim...

  11. Nitrous oxide inhalation anaesthesia in the presence of intraocular gas can cause irreversible blindness.

    Science.gov (United States)

    Lockwood, A J; Yang, Y F

    2008-03-08

    Nitrous oxide inhalation sedation is frequently used in dental and other surgical procedures. We report the case of a patient with intraocular gas who developed sudden elevation in intraocular pressure and blindness as a result of nitrous oxide anaesthesia. All medical and dental personnel administering nitrous oxide inhalation should be aware that this is contraindicated in patients with intraocular gas.

  12. The atmosphere of heaven: the 1799 nitrous oxide researches reconsidered.

    Science.gov (United States)

    Jay, Mike

    2009-09-20

    Thomas Beddoes's and Humphry Davy's accounts of the nitrous oxide experiments carried out at the Pneumatic Institution in 1799 include extravagant descriptions of its mind-altering effects. Many people, both at the time and subsequently, have considered these descriptions to be the product not of the gas but of its subjects' overheated imaginations. To what extent were these effects 'all in the mind' of the experimenters? Modern understandings of nitrous oxide throw new light on this question; but it was also considered, and resolved in different ways, by Beddoes and Davy themselves.

  13. 2004 Methane and Nitrous Oxide Emissions from Manure Management in South Africa

    Directory of Open Access Journals (Sweden)

    Mokhele Edmond Moeletsi

    2015-03-01

    Full Text Available Manure management in livestock makes a significant contribution towards greenhouse gas emissions in the Agriculture; Forestry and Other Land Use category in South Africa. Methane and nitrous oxide emissions are prevalent in contrasting manure management systems; promoting anaerobic and aerobic conditions respectively. In this paper; both Tier 1 and modified Tier 2 approaches of the IPCC guidelines are utilized to estimate the emissions from South African livestock manure management. Activity data (animal population, animal weights, manure management systems, etc. were sourced from various resources for estimation of both emissions factors and emissions of methane and nitrous oxide. The results show relatively high methane emissions factors from manure management for mature female dairy cattle (40.98 kg/year/animal, sows (25.23 kg/year/animal and boars (25.23 kg/year/animal. Hence, contributions for pig farming and dairy cattle are the highest at 54.50 Gg and 32.01 Gg respectively, with total emissions of 134.97 Gg (3104 Gg CO2 Equivalent. Total nitrous oxide emissions are estimated at 7.10 Gg (2272 Gg CO2 Equivalent and the three main contributors are commercial beef cattle; poultry and small-scale beef farming at 1.80 Gg; 1.72 Gg and 1.69 Gg respectively. Mitigation options from manure management must be taken with care due to divergent conducive requirements of methane and nitrous oxide emissions requirements.

  14. Nitrous oxide and serious morbidity and mortality in the POISE trial.

    Science.gov (United States)

    Leslie, Kate; Myles, Paul; Devereaux, Philip J; Forbes, Andrew; Rao-Melancini, Purnima; Williamson, Elizabeth; Xu, Shouchun; Foex, Pierre; Pogue, Janice; Arrieta, Maribel; Bryson, Gregory L; Paul, James; Paech, Michael J; Merchant, Richard N; Choi, Peter T; Badner, Neal; Peyton, Philip; Sear, John W; Yang, Homer

    2013-05-01

    In this post hoc subanalysis of the Perioperative Ischemic Evaluation (POISE) trial, we sought to determine whether nitrous oxide was associated with the primary composite outcome of cardiovascular death, nonfatal myocardial infarction (MI), and nonfatal cardiac arrest within 30 days of randomization. The POISE trial of perioperative β-blockade was undertaken in 8351 patients. Nitrous oxide anesthesia was defined as the coadministration of nitrous oxide in patients receiving general anesthesia, with or without additional neuraxial blockade or peripheral nerve blockade. Logistic regression, with inverse probability weighting using estimated propensity scores, was used to determine the association of nitrous oxide with the primary outcome, MI, stroke, death, and clinically significant hypotension. Nitrous oxide was administered to 1489 (29%) of the 5133 patients included in this analysis. Nitrous oxide had no significant effect on the risk of the primary outcome (112 [7.5%] vs 248 [6.9%]; odds ratio [OR], 1.08; 95% confidence interval [CI], 0.82-1.44; 99% CI, 0.75-1.57; P = 0.58), MI (89 [6.0] vs 204 [5.6]; OR, 0.99; 95% CI, 0.75-1.31; 99% CI, 0.69-1.42; P = 0.94), stroke (6 [0.4%] vs 28 [0.8%]; OR, 0.85; 95% CI, 0.26-2.82; 99% CI, 0.17-4.11; P = 0.79), death (40 [2.7%] vs 100 [2.8%]; OR, 1.04; 95% CI, 0.6-1.81; 99% CI, 0.51-2.15; P = 0.88) or clinically significant hypotension (219 [14.7%] vs 544 [15.0%]; OR, 0.92; 95% CI, 0.74-1.15; 99% CI, 0.70-1.23; P = 0.48). In this post hoc subanalysis, nitrous oxide was not associated with an increased risk of adverse outcomes in the POISE trial patients. This analysis was limited by the observational nature of the data and the lack of information on the concentration and duration of nitrous oxide administration. Further randomized controlled trial evidence is required.

  15. Compilation of a global inventory of emissions of nitrous oxide

    NARCIS (Netherlands)

    Bouwman, A.F.

    1995-01-01

    A global inventory with 1°x1° resolution was compiled of emissions of nitrous oxide (N 2 O) to the atmosphere, including emissions from soils under natural vegetation, fertilized agricultural land, grasslands and animal excreta, biomass burning, forest clearing,

  16. Direct methane and nitrous oxide emissions of monogastric livestock ...

    African Journals Online (AJOL)

    The Intergovernmental Panel on Climate Change (IPCC) methodology adapted to tropical production systems was used to calculate methane (CH4) and nitrous oxide (N2O) emissions. The non-ruminant sector is a minor GHG contributor compared with ruminant CH4 and N2O emissions. The pig industry and ostrich ...

  17. Shell biofilm-associated nitrous oxide production in marine molluscs

    DEFF Research Database (Denmark)

    Heisterkamp, I.M.; Schramm, Andreas; Larsen, Lone Heimann

    2013-01-01

    Emission of the greenhouse gas nitrous oxide (N2O) from freshwater and terrestrial invertebrates has exclusively been ascribed to N2O production by ingested denitrifying bacteria in the anoxic gut of the animals. Our study of marine molluscs now shows that also microbial biofilms on shell surfaces...

  18. Nitrous oxide emissions from the Gulf of Mexico Hypoxic Zone

    Science.gov (United States)

    The production of nitrous oxide (N2O), a potent greenhouse gas, in hypoxic coastal zones remains poorly characterized due to a lack of data, though large nitrogen inputs and deoxygenation typical of these systems create the potential for large N2O emissions. We report the first N...

  19. Nitrous oxide emission from denitrification in stream and river networks

    Science.gov (United States)

    Nitrous oxide (N2O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N2O via microbial denitrification which converts N to N2O and dinitrog...

  20. Nitrous Oxide Emissions after Application of Manure-Derived Fertiliseres

    DEFF Research Database (Denmark)

    Zhu, Kun

    Livestock manure is widely used as nitrogen (N) fertiliser and its application contributes a substantial proportion of N inputs to cropland. One of the major concerns with application of livestock manure is the loss of N through emissions of nitrous oxide (N2O) and the subsequent impact on global...

  1. Strategies to mitigate nitrous oxide emissions from herbivore production systems

    DEFF Research Database (Denmark)

    Schils, R L M; Eriksen, Jørgen; Ledgard, S F

    2013-01-01

    Herbivores are a significant source of nitrous oxide (N2O) emissions. They account for a large share of manure-related N2O emissions, as well as soil-related N2O emissions through the use of grazing land, and land for feed and forage production. It is widely acknowledged that mitigation measures...

  2. Municipal gravity sewers: an unrecognised source of nitrous oxide

    Science.gov (United States)

    Nitrous oxide (N2O) is a primary ozone-depleting substance and powerful greenhouse gas. N2O emissions from secondary-level wastewater treatment processes are relatively well understood as a result of intensive international research effort in recent times, yet little information...

  3. Nitrous oxide emissions from the Arabian Sea: A synthesis

    Digital Repository Service at National Institute of Oceanography (India)

    Bange, H.W.; Andreae, M.O.; Lal, S.; Law, C.S.; Naqvi, S.W.A; Patra, P.K.; Rixen, P.K.; Upstill-Goddard, R.C.

    High-resolution (1 degree x 1 degree longitude) seasonal and annual nitrous oxide (N sub(2) O) concentration fields for the Arabian Sea surface layer using a database containing more than 2400 values measured between December 1977 and July 1997...

  4. Atmospheric nitrous oxide uptake in boreal spruce forest soil

    Science.gov (United States)

    Siljanen, Henri; Welti, Nina; Heikkinen, Juha; Biasi, Christina; Martikainen, Pertti

    2017-04-01

    Nitrous oxide (N2O) uptake from the atmosphere has been found in forest soils but environmental factors controlling the uptake and its atmospheric impact are poorly known. We measured N2O fluxes over growing season in a boreal spruce forest having control plots and plots with long nitrogen fertilization history. Also methane (CH4) fluxes were measured to compare the atmospheric impact of N2O and CH4fluxes. Soil chemical and physical characteristics and climatic conditions were measured as background data. Nitrous oxide consumption and uptake mechanisms were measured in complementary laboratory incubation experiments using stable isotope approaches. Gene transcript numbers of nitrous oxide reductase (nosZ) I and II genes were quantified along the incubation with elevated N2O atmosphere. The spruce forests without fertilization history showed highest N2O uptake rates whereas pine forest had low emissions. Nitrous oxide uptake correlated positively with soil moisture, high soil silt content, and low temperature. Nitrous oxide uptake varied seasonally, being highest in spring and autumn when temperature was low and water content was high. The spruce forest was sink for CH4.Methane fluxes were decoupled from the N2O fluxes (i.e. when the N2O uptake was high the CH4 uptake was low). By using GWP approach, the cooling effect of N2O uptake was on average 30% of the cooling effect of CH4 uptake in spruce forest without fertilization. Anoxic conditions promoted higher N2O consumption rates in all soils. Gene transcription of nosZ-I genes were activated at beginning of the incubation. However, atypical/clade-II nosZ was not detected. These results suggests, that also N2O uptake rates have to be considered when accounting for the GHG budget of spruce forests.

  5. Nitrous oxide emissions from the Arabian Sea: A synthesis

    Directory of Open Access Journals (Sweden)

    H. W. Bange

    2001-01-01

    Full Text Available We computed high-resolution (1º latitude x  1º longitude seasonal and annual nitrous oxide (N2O concentration fields for the Arabian Sea surface layer using a database containing more than 2400 values measured between December 1977 and July 1997. N2O concentrations are highest during the southwest (SW monsoon along the southern Indian continental shelf. Annual emissions range from 0.33 to 0.70 Tg N2O and are dominated by fluxes from coastal regions during the SW and northeast monsoons. Our revised estimate for the annual N2O flux from the Arabian Sea is much more tightly constrained than the previous consensus derived using averaged in-situ data from a smaller number of studies. However, the tendency to focus on measurements in locally restricted features in combination with insufficient seasonal data coverage leads to considerable uncertainties of the concentration fields and thus in the flux estimates, especially in the coastal zones of the northern and eastern Arabian Sea. The overall mean relative error of the annual N2O emissions from the Arabian Sea was estimated to be at least 65%.

  6. Closing the Gaps in the Budgets of Methane and Nitrous Oxide

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Aslam; Rice, Andrew; Rasmussen, Reinhold

    2013-11-22

    Together methane and nitrous oxide contribute almost 40% of the estimated increase in radiative forcing caused by the buildup of greenhouse gases during the last 250 years (IPCC, 2007). These increases are attributed to human activities. Since the emissions of these gases are from biogenic sources and closely associated with living things in the major terrestrial ecosystems of the world, climate change is expected to cause feedbacks that may further increase emissions even from systems normally classified as natural. Our results support the idea that while past increases of methane were driven by direct emissions from human activities, some of these have reached their limits and that the future of methane changes may be determined by feedbacks from warming temperatures. The greatly increased current focus on the arctic and the fate of the carbon frozen in its permafrost is an example of such a feedback that could exceed the direct increases caused by future human activities (Zimov et al. 2006). Our research was aimed at three broad areas to address open questions about the global budgets of methane and nitrous oxide. These areas of inquiry were: The processes by which methane and nitrous oxide are emitted, new sources such as trees and plants, and integration of results to refine the global budgets both at present and of the past decades. For the process studies the main research was to quantify the effect of changes in the ambient temperature on the emissions of methane and nitrous oxide from rice agriculture. Additionally, the emissions of methane and nitrous oxide under present conditions were estimated using the experimental data on how fertilizer applications and water management affect emissions. Rice was chosen for detailed study because it is a prototype system of the wider terrestrial source, its role in methane emissions is well established, it is easy to cultivate and it represents a major anthropogenic source. Here we will discuss the highlights of the

  7. Nitrous oxide and methane emissions from cryptogamic covers.

    Science.gov (United States)

    Lenhart, Katharina; Weber, Bettina; Elbert, Wolfgang; Steinkamp, Jörg; Clough, Tim; Crutzen, Paul; Pöschl, Ulrich; Keppler, Frank

    2015-10-01

    Cryptogamic covers, which comprise some of the oldest forms of terrestrial life on Earth (Lenton & Huntingford, ), have recently been found to fix large amounts of nitrogen and carbon dioxide from the atmosphere (Elbert et al., ). Here we show that they are also greenhouse gas sources with large nitrous oxide (N2 O) and small methane (CH4 ) emissions. Whilst N2 O emission rates varied with temperature, humidity, and N deposition, an almost constant ratio with respect to respiratory CO2 emissions was observed for numerous lichens and bryophytes. We employed this ratio together with respiration data to calculate global and regional N2 O emissions. If our laboratory measurements are typical for lichens and bryophytes living on ground and plant surfaces and scaled on a global basis, we estimate a N2 O source strength of 0.32-0.59 Tg year(-1) for the global N2 O emissions from cryptogamic covers. Thus, our emission estimate might account for 4-9% of the global N2 O budget from natural terrestrial sources. In a wide range of arid and forested regions, cryptogamic covers appear to be the dominant source of N2 O. We suggest that greenhouse gas emissions associated with this source might increase in the course of global change due to higher temperatures and enhanced nitrogen deposition. © 2015 John Wiley & Sons Ltd.

  8. Microwave sterilization of nitrous oxide nasal hoods contaminated with virus

    Energy Technology Data Exchange (ETDEWEB)

    Young, S.K.; Graves, D.C.; Rohrer, M.D.; Bulard, R.A.

    1985-12-01

    Although there exists a desire to eliminate the possibility of cross-infection from microbial contaminated nitrous oxide nasal hoods, effective and practical methods of sterilization in a dental office are unsatisfactory. Microwaves have been used to sterilize certain contaminated dental instruments without damage. In this study nasal hoods contaminated with rhinovirus, parainfluenza virus, adenovirus, and herpes simplex virus were sterilized in a modified microwave oven. Ninety-five percent of the virus activity was destroyed after 1 minute of exposure of the contaminated nasal hoods to microwaves. By the end of 4 minutes, complete inactivation of all four viruses was found. Repeated exposure of the nasal hoods to microwaves resulted in no damage to their texture and flexibility. Microwave sterilization may potentially provide a simple and practical method of sterilizing nitrous oxide anesthesia equipment in a dental or medical practice.

  9. Microwave sterilization of nitrous oxide nasal hoods contaminated with virus.

    Science.gov (United States)

    Young, S K; Graves, D C; Rohrer, M D; Bulard, R A

    1985-12-01

    Although there exists a desire to eliminate the possibility of cross-infection from microbial contaminated nitrous oxide nasal hoods, effective and practical methods of sterilization in a dental office are unsatisfactory. Microwaves have been used to sterilize certain contaminated dental instruments without damage. In this study nasal hoods contaminated with rhinovirus, parainfluenza virus, adenovirus, and herpes simplex virus were sterilized in a modified microwave oven. Ninety-five percent of the virus activity was destroyed after 1 minute of exposure of the contaminated nasal hoods to microwaves. By the end of 4 minutes, complete inactivation of all four viruses was found. Repeated exposure of the nasal hoods to microwaves resulted in no damage to their texture and flexibility. Microwave sterilization may potentially provide a simple and practical method of sterilizing nitrous oxide anesthesia equipment in a dental or medical practice.

  10. Thermodynamics of dissolved nitrogen, nitrous oxide, and ammonia in perfluorodecalin

    Science.gov (United States)

    Moshnyaga, A. V.; Khoroshilov, A. V.; Selivanova, D. I.; Aksenova, D. M.

    2017-11-01

    The solubility of N2, N2O, and NH3 is studied in different organic solvents. The best dissolution (0.27 ppm) is found to be for N2O in perfluorodecalin at 291 K and a pressure of 99 kPa. The dependence of N2O solubility in perfluorodecalin on pressure is studied at 291 K. The Gibbs energy of the solubility of nitrogen, nitrous oxide, and ammonia in perfluorodecalin is calculated.

  11. Maternal Expectations and Experiences of Labor Analgesia With Nitrous Oxide

    OpenAIRE

    Pasha, Hajar; Basirat, Zahra; Hajahmadi, Mahmood; Bakhtiari, Afsaneh; Faramarzi, Mahbobeh; Salmalian, Hajar

    2012-01-01

    Background Although there are various methods for painless delivery such as using entonox gas, most of the people are unfamiliar or concerned about it yet. Objectives The purpose of this study was to assess maternal expectations and experience of labor analgesia with nitrous oxide. Patients and Methods In a clinical trial study, 98 pregnant women in active phase of delivery were studied randomly in two groups (intervention group = 49, control group = 49) after obtaining written consent. Effic...

  12. Nitrous oxide (N2O) emission from aquaculture: a review.

    Science.gov (United States)

    Hu, Zhen; Lee, Jae Woo; Chandran, Kartik; Kim, Sungpyo; Khanal, Samir Kumar

    2012-06-19

    Nitrous oxide (N(2)O) is an important greenhouse gas (GHG) which has a global warming potential 310 times that of carbon dioxide (CO(2)) over a hundred year lifespan. N(2)O is generated during microbial nitrification and denitrification, which are common in aquaculture systems. To date, few studies have been conducted to quantify N(2)O emission from aquaculture. Additionally, very little is known with respect to the microbial pathways through which N(2)O is formed in aquaculture systems. This review suggests that aquaculture can be an important anthropogenic source of N(2)O emission. The global N(2)O-N emission from aquaculture in 2009 is estimated to be 9.30 × 10(10) g, and will increase to 3.83 × 10(11)g which could account for 5.72% of anthropogenic N(2)O-N emission by 2030 if the aquaculture industry continues to increase at the present annual growth rate (about 7.10%). The possible mechanisms and various factors affecting N(2)O production are summarized, and two possible methods to minimize N(2)O emission, namely aquaponic and biofloc technology aquaculture, are also discussed. The paper concludes with future research directions.

  13. Source Tracking of Nitrous Oxide using A Quantum Cascade ...

    Science.gov (United States)

    Nitrous oxide is an important greenhouse gas and ozone depleting substance. Nitrification and denitrification are two major biological pathways that are responsible for soil emissions of N2O. However, source tracking of in-situ or laboratory N2O production is still challenging to soil scientists. The objective of this study was to introduce the use of a new technology, quantum cascade laser (QCL) spectroscopy, which allows for significantly improved accuracy and precision to continuously measure real-time N2O for source tracking. This data provides important emission inventory information to air quality and atmospheric chemistry models. The task demonstrated that QCL spectroscopy can measure the flux of nitrous oxide at ambient and well as elevated concentrations in real time. The fractionation of the nitrous oxide produced by microbial processing of nitrate can be measured and characterized as isotopic signatures related to the nitrifying or denitrifying state of the microbial communities. This has important implications for monitoring trace gases in the atmosphere. The data produced by this system will provide clients including the air quality and climate change communities with needed information on the sources and strengths of N2O emissions for modeling and research into mitigation strategies to reduce overall GHG emissions in agricultural systems.

  14. Production of oceanic nitrous oxide by ammonia-oxidizing archaea

    Directory of Open Access Journals (Sweden)

    C. R. Löscher

    2012-07-01

    Full Text Available The recent finding that microbial ammonia oxidation in the ocean is performed by archaea to a greater extent than by bacteria has drastically changed the view on oceanic nitrification. The numerical dominance of archaeal ammonia-oxidizers (AOA over their bacterial counterparts (AOB in large parts of the ocean leads to the hypothesis that AOA rather than AOB could be the key organisms for the oceanic production of the strong greenhouse gas nitrous oxide (N2O that occurs as a by-product of nitrification. Very recently, enrichment cultures of marine ammonia-oxidizing archaea have been reported to produce N2O.

    Here, we demonstrate that archaeal ammonia monooxygenase genes (amoA were detectable throughout the water column of the eastern tropical North Atlantic (ETNA and eastern tropical South Pacific (ETSP Oceans. Particularly in the ETNA, comparable patterns of abundance and expression of archaeal amoA genes and N2O co-occurred in the oxygen minimum, whereas the abundances of bacterial amoA genes were negligible. Moreover, selective inhibition of archaea in seawater incubations from the ETNA decreased the N2O production significantly. In studies with the only cultivated marine archaeal ammonia-oxidizer Nitrosopumilus maritimus SCM1, we provide the first direct evidence for N2O production in a pure culture of AOA, excluding the involvement of other microorganisms as possibly present in enrichments. N. maritimus showed high N2O production rates under low oxygen concentrations comparable to concentrations existing in the oxycline of the ETNA, whereas the N2O production from two AOB cultures was comparably low under similar conditions. Based on our findings, we hypothesize that the production of N2O in tropical ocean areas results mainly from archaeal nitrification and will be affected by the predicted decrease in dissolved

  15. An overview of the revised 1996 IPCC guidelines for national greenhouses gas inventory methodology for nitrous oxide from agriculture

    NARCIS (Netherlands)

    Mosier, A.; Kroeze, C.; Nevison, C.; Oenema, O.; Seitzinger, S.; Cleemput, van O.

    1999-01-01

    The IPCC Guidelines for National Greenhouse Gas Inventories provide default methodologies for estimating emissions of the most important greenhouse gases at a national scale. The methodology for estimating emissions of nitrous oxide (N2O) from agriculture was revised in 1996 by an international

  16. Nitrous oxide-oxygen: a new look at a very old technique.

    Science.gov (United States)

    Malamed, Stanley F; Clark, Moris S

    2003-05-01

    Inhalation sedation utilizing nitrous oxide-oxygen has been a primary technique in the management of dental fears and anxieties for more than 150 years and remains so today. Though other, more potent, anesthetics have been introduced, nitrous oxide is still the most used gaseous anesthetic in the world. Administered properly with well-maintained equipment, the nitrous oxide-oxygen technique has an extremely high success rate coupled with a very low rate of adverse effects and complications.

  17. Nitrous oxide emission from denitrification in stream and river networks

    Science.gov (United States)

    Beaulieu, J.J.; Tank, J.L.; Hamilton, S.K.; Wollheim, W.M.; Hall, R.O.; Mulholland, P.J.; Peterson, B.J.; Ashkenas, L.R.; Cooper, L.W.; Dahm, Clifford N.; Dodds, W.K.; Grimm, N. B.; Johnson, S.L.; McDowell, W.H.; Poole, G.C.; Maurice, Valett H.; Arango, C.P.; Bernot, M.J.; Burgin, A.J.; Crenshaw, C.L.; Helton, A.M.; Johnson, L.T.; O'Brien, J. M.; Potter, J.D.; Sheibley, R.W.; Sobota, D.J.; Thomas, S.M.

    2011-01-01

    Nitrous oxide (N2O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N 2O via microbial denitrification that converts N to N2O and dinitrogen (N2). The fraction of denitrified N that escapes as N2O rather than N2 (i.e., the N2O yield) is an important determinant of how much N2O is produced by river networks, but little is known about the N2O yield in flowing waters. Here, we present the results of whole-stream 15N-tracer additions conducted in 72 headwater streams draining multiple land-use types across the United States. We found that stream denitrification produces N2O at rates that increase with stream water nitrate (NO3-) concentrations, but that production, but does not increase the N2O yield. In our study, most streams were sources of N2O to the atmosphere and the highest emission rates were observed in streams draining urban basins. Using a global river network model, we estimate that microbial N transformations (e.g., denitrification and nitrification) convert at least 0.68 Tg??y -1 of anthropogenic N inputs to N2O in river networks, equivalent to 10% of the global anthropogenic N2O emission rate. This estimate of stream and river N2O emissions is three times greater than estimated by the Intergovernmental Panel on Climate Change.

  18. The contribution of manure and fertilizer nitrogen to atmospheric nitrous oxide since 1860

    Science.gov (United States)

    Davidson, Eric A.

    2009-09-01

    Atmospheric nitrous oxide concentrations have been increasing since the industrial revolution and currently account for 6% of total anthropogenic radiative forcing. Microbial production in soils is the dominant nitrous oxide source; this has increased with increasing use of nitrogen fertilizers. However, fertilizer use alone cannot account for the historical trends of atmospheric concentrations of nitrous oxide. Here, I analyse atmospheric concentrations, industrial sources of nitrous oxide, and fertilizer and manure production since 1860. Before 1960, agricultural expansion, including livestock production, may have caused globally significant mining of soil nitrogen, fuelling a steady increase in atmospheric nitrous oxide. After 1960, the rate of the increase rose, due to accelerating use of synthetic nitrogen fertilizers. Using a regression model, I show that 2.0% of manure nitrogen and 2.5% of fertilizer nitrogen was converted to nitrous oxide between 1860 and 2005; these percentage contributions explain the entire pattern of increasing nitrous oxide concentrations over this period. Consideration of processes that re-concentrate soil nitrogen, such as manure production by livestock, improved `hind-casting' of nitrous oxide emissions. As animal protein consumption in human diets increases globally, management of manure will be an important component of future efforts to reduce anthropogenic nitrous oxide sources.

  19. Health Hazard Evaluation Report HETA 84-204-1600, Dental Health Associates, Paoli, Pennsylvania. [Nitrous oxide

    Energy Technology Data Exchange (ETDEWEB)

    Crandall, M.S.

    1985-06-01

    Area air and breathing-zone samples were analyzed for nitrous oxide at Dental Health Associates, Paoli, Pennsylvania on August 2, 1984. The evaluation was requested by a dental assistant because of general concern about the extent of nitrous oxide exposure, especially since the office was not equipped with a waste-anesthetic gas-scavenging system. The author recommends installing a waste anesthetic gas scavenging system with a dedicated exhaust. The nitrous oxide delivery and mixing system should be checked for leaks monthly and work practices for handling nitrous oxide should be improved.

  20. Continuous measurements of nitrous oxide isotopomers during incubation experiments

    DEFF Research Database (Denmark)

    Winther, Malte Nordmann; Balslev-Harder, David; Christensen, Søren

    2016-01-01

    Nitrous oxide (N2O) is an important and strong greenhouse gas in the atmosphere and part of a feed-back loop with climate. N2O is produced by microbes during nitrification and denitrification in terrestrial and aquatic ecosystems. The main sinks for N2O are turnover by denitrification...... and photolysis and photo-oxidation in the stratosphere. The position of the isotope 15N in the linear N = N = O molecule can be distinguished between the central or terminal position (isotopomers of N2O). It has been demonstrated that nitrifying and denitrifying microbes have a different relative preference...

  1. Gross nitrous oxide production drives net nitrous oxide fluxes across a salt marsh landscape.

    Science.gov (United States)

    Yang, Wendy H; Silver, Whendee L

    2016-06-01

    Sea level rise will change inundation regimes in salt marshes, altering redox dynamics that control nitrification - a potential source of the potent greenhouse gas, nitrous oxide (N2 O) - and denitrification, a major nitrogen (N) loss pathway in coastal ecosystems and both a source and sink of N2 O. Measurements of net N2 O fluxes alone yield little insight into the different effects of redox conditions on N2 O production and consumption. We used in situ measurements of gross N2 O fluxes across a salt marsh elevation gradient to determine how soil N2 O emissions in coastal ecosystems may respond to future sea level rise. Soil redox declined as marsh elevation decreased, with lower soil nitrate and higher ferrous iron in the low marsh compared to the mid and high marshes (P < 0.001 for both). In addition, soil oxygen concentrations were lower in the low and mid-marshes relative to the high marsh (P < 0.001). Net N2 O fluxes differed significantly among marsh zones (P = 0.009), averaging 9.8 ± 5.4 μg N m(-2)  h(-1) , -2.2 ± 0.9 μg N m(-2)  h(-1) , and 0.67 ± 0.57 μg N m(-2)  h(-1) in the low, mid, and high marshes, respectively. Both net N2 O release and uptake were observed in the low and high marshes, but the mid-marsh was consistently a net N2 O sink. Gross N2 O production was highest in the low marsh and lowest in the mid-marsh (P = 0.02), whereas gross N2 O consumption did not differ among marsh zones. Thus, variability in gross N2 O production rates drove the differences in net N2 O flux among marsh zones. Our results suggest that future studies should focus on elucidating controls on the processes producing, rather than consuming, N2 O in salt marshes to improve our predictions of changes in net N2 O fluxes caused by future sea level rise. © 2015 John Wiley & Sons Ltd.

  2. Exposure control practices for administering nitrous oxide: A survey of dentists, dental hygienists, and dental assistants.

    Science.gov (United States)

    Boiano, James M; Steege, Andrea L; Sweeney, Marie H

    2017-06-01

    Engineering, administrative, and work practice controls have been recommended for many years to minimize exposure to nitrous oxide during dental procedures. To better understand the extent to which these exposure controls are used, the NIOSH Health and Safety Practices Survey of Healthcare Workers was conducted among members of professional practice organizations representing dentists, dental hygienists and dental assistants. The anonymous, modular, web-based survey was completed by 284 dental professionals in private practice who administered nitrous oxide to adult and/or pediatric patients in the seven days prior to the survey. Use of primary engineering controls (i.e., nasal scavenging mask and/or local exhaust ventilation (LEV) near the patient's mouth) was nearly universal, reported by 93% and 96% of respondents who administered to adult (A) and pediatric (P) patients, respectively. However, adherence to other recommended precautionary practices were lacking to varying degrees, and were essentially no different among those administering nitrous oxide to adult or pediatric patients. Examples of work practices which increase exposure risk, expressed as percent of respondents, included: not checking nitrous oxide equipment for leaks (41% A; 48% P); starting nitrous oxide gas flow before delivery mask or airway mask was applied to patient (13% A; 12% P); and not turning off nitrous oxide gas flow before turning off oxygen flow to the patient (8% A; 7% P). Absence of standard procedures to minimize worker exposure to nitrous oxide (13% of all respondents) and not being trained on safe handling and administration of nitrous oxide (3%) were examples of breaches of administrative controls which may also increase exposure risk. Successful management of nitrous oxide emissions should include properly fitted nasal scavenging masks, supplemental LEV (when nitrous oxide levels cannot be adequately controlled using nasal masks alone), adequate general ventilation, regular

  3. Assessment of nitrous oxide and methane emissions for California agriculture

    Science.gov (United States)

    Horwath, W. R.; Burger, M.; Assa, Y.; Wilson, T. J.

    2012-12-01

    The California Global Warming Solutions Act of 2006 (AB 32) mandates comprehensive strategies to reduce nitrous oxide (N2O) and methane (CH4) emissions. In agriculture crop production, sources of N2O are related to nitrogen fertilization while CH4 emission is associated with rice production. More than half the GHG emissions from agriculture are attributed to N2O production. Currently, baseline N2O emission data for most cropping systems in the State is lacking. Estimates of CH4 emission in rice have been established from previous studies, but a lack of information exists for its expansion into the San Joaquin Delta to address subsidence issues. The paucity of N2O emission data has hampered biogeochemical modeling efforts. The objectives of this assessment are to (1) measure annual N2O and CH4 emissions for major California crops (vineyards, almonds, tomato, wheat, alfalfa, lettuce, and rice) under typical management practices, (2) characterize the effects of environmental factors on the temporal profile of N2O and CH4 emissions, and (3) determine N2O emission factors. The growth of rice in Delta peat soils produced highly variable CH4 emissions depending on tillage intensity. In 2010, standard tillage produced 184 kg CH4-C/ha while in 2011 after deep plowing placing rice residue deeper into the soil, only 26 kg CH4-C/ha was observed. In processing tomato systems, an average 2.5 kg N2O-N/ha was emitted with standard fertilization (160 kg N / ha), similar to background emissions and those from a drip irrigated system, while 4.0 to 5.8 kg N2O-N /ha y-1 was emitted at fertilizer rates of 225 and 300 kg N /ha (see Fig. 1 for example of temporal sources of emissions). About half the annual emissions were emitted within 3 d after the first seasonal rainfall event. In other tomato studies, estimated losses of fertilizer N as N2O were 0.38 ± 0.03 kg/ha y-1 in a drip irrigated system and 1.79 ± 0.21 kg/ha y-1 in furrow irrigated system, which was equivalent to 0.19% and 0

  4. Methane and nitrous oxide in the ice core record.

    Science.gov (United States)

    Wolff, Eric; Spahni, Renato

    2007-07-15

    Polar ice cores contain, in trapped air bubbles, an archive of the concentrations of stable atmospheric gases. Of the major non-CO2 greenhouse gases, methane is measured quite routinely, while nitrous oxide is more challenging, with some artefacts occurring in the ice and so far limited interpretation. In the recent past, the ice cores provide the only direct measure of the changes that have occurred during the industrial period; they show that the current concentration of methane in the atmosphere is far outside the range experienced in the last 650,000 years; nitrous oxide is also elevated above its natural levels. There is controversy about whether changes in the pre-industrial Holocene are natural or anthropogenic in origin. Changes in wetland emissions are generally cited as the main cause of the large glacial-interglacial change in methane. However, changing sinks must also be considered, and the impact of possible newly described sources evaluated. Recent isotopic data appear to finally rule out any major impact of clathrate releases on methane at these time-scales. Any explanation must take into account that, at the rapid Dansgaard-Oeschger warmings of the last glacial period, methane rose by around half its glacial-interglacial range in only a few decades. The recent EPICA Dome C (Antarctica) record shows that methane tracked climate over the last 650,000 years, with lower methane concentrations in glacials than interglacials, and lower concentrations in cooler interglacials than in warmer ones. Nitrous oxide also shows Dansgaard-Oeschger and glacial-interglacial periodicity, but the pattern is less clear.

  5. Nitrous oxide from moving bed based integrated fixed film activated sludge membrane bioreactors.

    Science.gov (United States)

    Mannina, Giorgio; Capodici, Marco; Cosenza, Alida; Di Trapani, Daniele; Laudicina, Vito Armando; Ødegaard, Hallvard

    2017-02-01

    The present paper reports the results of a nitrous oxide (N2O) production investigation in a moving bed based integrated fixed film activated sludge (IFAS) membrane bioreactor (MBR) pilot plant designed in accordance with the University of Cape Town layout for biological phosphorous removal. Gaseous and liquid samples were collected in order to measure the gaseous as well as the dissolved concentration of N2O. Furthermore, the gas flow rate from each reactor was measured and the gas flux was estimated. The results confirmed that the anoxic reactor represents the main source of nitrous oxide production. A significant production of N2O was, however, also found in the anaerobic reactor, thus indicating a probable occurrence of the denitrifying phosphate accumulating organism activity. The highest N2O fluxes were emitted from the aerated reactors (3.09 g N2ON m-2 h-1 and 9.87 g N2ON m-2 h-1, aerobic and MBR tank, respectively). The emission factor highlighted that only 1% of the total treated nitrogen was emitted from the pilot plant. Furthermore, the measured N2O concentrations in the permeate flow were comparable with other reactors. Nitrous oxide mass balances outlined a moderate production also in the MBR reactor despite the low hydraulic retention time. On the other hand, the mass balance showed that in the aerobic reactor a constant consumption of nitrous oxide (up to almost 15 mg N2O h-1) took place, due to the high amount of stripped gas. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. [Technology of nitrous oxide/oxygen inhalation sedation and its clinical application in pediatric dentistry].

    Science.gov (United States)

    Zhong, Tian; Hu, Daoyong

    2014-02-01

    Dental fear is a common problem in pediatric dentistry. Therefore, sedation for pediatric patients is an essential tool for anxiety management. Nitrous oxide/oxygen inhalation sedation is a safe, convenient, effective way to calm children. The review is about the technology of nitrous oxide/oxygen inhalation sedation and its clinical application in pediatric dentistry.

  7. Dynamics of Nitric Oxide and Nitrous Oxide Emission during Nitrogen Conversion Processes

    NARCIS (Netherlands)

    Kampschreur, M.J.

    2010-01-01

    Nitric oxide (NO) and nitrous oxide (N2O) emissions can be a serious threat to the environment. Rising levels of N2O in the atmosphere contribute to global warming and destruction of the ozone layer. This thesis describes an investigation on the emission of NO and N2O during nitrogen conversion

  8. Acute ST-Elevation Myocardial Infarction, a Unique Complication of Recreational Nitrous Oxide Use.

    Science.gov (United States)

    Indraratna, Praveen; Alexopoulos, Chris; Celermajer, David; Alford, Kevin

    2017-08-01

    A 28-year-old male was admitted to hospital with an acute ST-elevation myocardial infarction. This was in the context of recreational abuse of nitrous oxide. The prevalence of nitrous oxide use in Australia has not been formally quantified, however it is the second most commonly used recreational drug in the United Kingdom. Nitrous oxide has previously been shown to increase serum homocysteine levels. This patient was discovered to have an elevated homocysteine level at baseline, which was further increased after nitrous oxide consumption. Homocysteine has been linked to endothelial dysfunction and coronary atherosclerosis and this case report highlights one of the dangers of recreational abuse of nitrous oxide. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  9. Nitrous oxide emissions from one-step partial nitritation/anammox processes.

    Science.gov (United States)

    Yang, Jingjing; Trela, Jozef; Plaza, Elzbieta

    2016-12-01

    Measurements of nitrous oxide were made at pilot- and full-scale plants to evaluate greenhouse gas emissions from one-step partial nitritation/anammox processes applied in moving bed biofilm reactors treating reject water. It was found that 0.51-1.29% and 0.35-1.33% of the total nitrogen loads in the pilot- and full-scale reactor, respectively, were emitted as nitrous oxide. Between 80 and 90% of nitrous oxide emissions were in gaseous form and the rest amount was found in the reactor effluent; over 90% of nitrous oxide emissions occurred in the aerated period and less than 8% in the non-aerated period in the full-scale study. Nitrous oxide productions/consumptions were closely related to aeration and the nitrogen loads applied in the system.

  10. The Neurotoxicity of Nitrous Oxide: The Facts and “Putative” Mechanisms

    Science.gov (United States)

    Savage, Sinead; Ma, Daqing

    2014-01-01

    Nitrous oxide is a widely used analgesic agent, used also in combination with anaesthetics during surgery. Recent research has raised concerns about possible neurotoxicity of nitrous oxide, particularly in the developing brain. Nitrous oxide is an N-methyl-d-aspartate (NMDA)-antagonist drug, similar in nature to ketamine, another anaesthetic agent. It has been linked to post-operative cardiovascular problems in clinical studies. It is also widely known that exposure to nitrous oxide during surgery results in elevated homocysteine levels in many patients, but very little work has investigated the long term effect of these increased homocysteine levels. Now research in rodent models has found that homocysteine can be linked to neuronal death and possibly even cognitive deficits. This review aims to examine the current knowledge of mechanisms of action of nitrous oxide, and to describe some pathways by which it may have neurotoxic effects. PMID:24961701

  11. Effects of nitrous oxide on the rat heart in vivo: another inhalational anesthetic that preconditions the heart?

    NARCIS (Netherlands)

    Weber, Nina C.; Toma, Octavian; Awan, Saqib; Frässdorf, Jan; Preckel, Benedikt; Schlack, Wolfgang

    2005-01-01

    BACKGROUND: For nitrous oxide, a preconditioning effect on the heart has yet not been investigated. This is important because nitrous oxide is commonly used in combination with volatile anesthetics, which are known to precondition the heart. The authors aimed to clarify (1) whether nitrous oxide

  12. Portable nitrous oxide sensor for understanding agricultural and soil emissions

    Energy Technology Data Exchange (ETDEWEB)

    Stanton, Alan [Southwest Sciences, Inc., Santa Fe, NM (United States); Zondlo, Mark [Princeton Univ., NJ (United States); Gomez, Anthony [Southwest Sciences, Inc., Santa Fe, NM (United States); Pan, Da [Princeton Univ., NJ (United States)

    2017-02-27

    Nitrous oxide (N2O) is the third most important greenhouse gas (GHG,) with an atmospheric lifetime of ~114 years and a global warming impact ~300 times greater than that of carbon dioxide. The main cause of nitrous oxide’s atmospheric increase is anthropogenic emissions, and over 80% of the current global anthropogenic flux is related to agriculture, including associated land-use change. An accurate assessment of N2O emissions from agriculture is vital not only for understanding the global N2O balance and its impact on climate but also for designing crop systems with lower GHG emissions. Such assessments are currently hampered by the lack of instrumentation and methodologies to measure ecosystem-level fluxes at appropriate spatial and temporal scales. Southwest Sciences and Princeton University are developing and testing new open-path eddy covariance instrumentation for continuous and fast (10 Hz) measurement of nitrous oxide emissions. An important advance, now being implemented, is the use of new mid-infrared laser sources that enable the development of exceptionally low power (<10 W) compact instrumentation that can be used even in remote sites lacking in power. The instrumentation will transform the ability to measure and understand ecosystem-level nitrous oxide fluxes. The Phase II results included successful extended field testing of prototype flux instruments, based on quantum cascade lasers, in collaboration with Michigan State University. Results of these tests demonstrated a flux detection limit of 5 µg m-2 s-1 and showed excellent agreement and correlation with measurements using chamber techniques. Initial tests of an instrument using an interband cascade laser (ICL) were performed, verifying that an order of magnitude reduction in instrument power requirements can be realized. These results point toward future improvements and testing leading to introduction of a commercial open path instrument for N2O flux measurements that is truly portable and

  13. Nitrous oxide cooling in hybrid rocket nozzles

    Science.gov (United States)

    Lemieux, Patrick

    2010-02-01

    The Department of Mechanical Engineering at the California Polytechnic State University, San Luis Obispo, has developed an innovative program of experimental research and development on hybrid rocket motors (where the fuel and the oxidizer are in different phases prior to combustion). One project currently underway involves the development of aerospike nozzles for such motors. These nozzles, however, are even more susceptible to throat ablation than regular converging-diverging nozzles, due the nature of their flow expansion mechanism. This paper presents the result of a recent development project focused on reducing throat ablation in hybrid rocket motor nozzles. Although the method is specifically targeted at increasing the life and operating range of aerospike nozzles, this paper describes its proof-of-concept implementation on conventional nozzles. The method is based on a regenerative cooling mechanism that differs in practice from that used in liquid propellant motors. A series of experimental tests demonstrate that this new method is not only effective at reducing damage in the most ablative region of the nozzle, but that the nozzle can survive multiple test runs.

  14. Inventories and scenarios of nitrous oxide emissions

    Science.gov (United States)

    Davidson, Eric A.; Kanter, David

    2014-10-01

    Effective mitigation for N2O emissions, now the third most important anthropogenic greenhouse gas and the largest remaining anthropogenic source of stratospheric ozone depleting substances, requires understanding of the sources and how they may increase this century. Here we update estimates and their uncertainties for current anthropogenic and natural N2O emissions and for emissions scenarios to 2050. Although major uncertainties remain, ‘bottom-up’ inventories and ‘top-down’ atmospheric modeling yield estimates that are in broad agreement. Global natural N2O emissions are most likely between 10 and 12 Tg N2O-N yr-1. Net anthropogenic N2O emissions are now about 5.3 Tg N2O-N yr-1. Gross anthropogenic emissions by sector are 66% from agriculture, 15% from energy and transport sectors, 11% from biomass burning, and 8% from other sources. A decrease in natural emissions from tropical soils due to deforestation reduces gross anthropogenic emissions by about 14%. Business-as-usual emission scenarios project almost a doubling of anthropogenic N2O emissions by 2050. In contrast, concerted mitigation scenarios project an average decline of 22% relative to 2005, which would lead to a near stabilization of atmospheric concentration of N2O at about 350 ppb. The impact of growing demand for biofuels on future projections of N2O emissions is highly uncertain; N2O emissions from second and third generation biofuels could remain trivial or could become the most significant source to date. It will not be possible to completely eliminate anthropogenic N2O emissions from agriculture, but better matching of crop N needs and N supply offers significant opportunities for emission reductions.

  15. Nitrous oxide-related postoperative nausea and vomiting depends on duration of exposure.

    Science.gov (United States)

    Peyton, Philip J; Wu, Christine Yx

    2014-05-01

    Inclusion of nitrous oxide in the gas mixture has been implicated in postoperative nausea and vomiting (PONV) in numerous studies. However, these studies have not examined whether duration of exposure was a significant covariate. This distinction might affect the future place of nitrous oxide in clinical practice. PubMed listed journals reporting trials in which patients randomized to a nitrous oxide or nitrous oxide-free anesthetic for surgery were included, where the incidence of PONV within the first 24 postoperative hours and mean duration of anesthesia was reported. Meta-regression of the log risk ratio for PONV with nitrous oxide (lnRR PONVN2O) versus duration was performed. Twenty-nine studies in 27 articles met the inclusion criteria, randomizing 10,317 patients. There was a significant relationship between lnRR PONVN2O and duration (r = 0.51, P = 0.002). Risk ratio PONV increased 20% per hour of nitrous oxide after 45 min. The number needed to treat to prevent PONV by avoiding nitrous oxide was 128, 23, and 9 where duration was less than 1, 1 to 2, and over 2 h, respectively. The risk ratio for the overall effect of nitrous oxide on PONV was 1.21 (CIs, 1.04-1.40); P = 0.014. This duration-related effect may be via disturbance of methionine and folate metabolism. No clinically significant effect of nitrous oxide on the risk of PONV exists under an hour of exposure. Nitrous oxide-related PONV should not be seen as an impediment to its use in minor or ambulatory surgery.

  16. Nitrous oxide for labor analgesia: Utilization and predictors of conversion to neuraxial analgesia.

    Science.gov (United States)

    Sutton, Caitlin D; Butwick, Alexander J; Riley, Edward T; Carvalho, Brendan

    2017-08-01

    We examined the characteristics of women who choose nitrous oxide for labor analgesia and identified factors that predict conversion from nitrous oxide to labor neuraxial analgesia. Retrospective descriptive study. Labor and Delivery Ward. 146 pregnant women who used nitrous oxide for analgesia during labor and delivery between September 2014 and September 2015. Chart review only. Demographic, obstetric, and intrapartum characteristics of women using nitrous oxide were examined. Multivariable logistic regression was performed to identify factors associated with conversion from nitrous oxide to neuraxial analgesia. Data are presented as n (%), median [IQR], adjusted relative risk (aRR), and 95% confidence intervals (CI) as appropriate. During the study period, 146 women used nitrous oxide for labor analgesia (accounting for 3% of the total deliveries). The majority (71.9%) of women who used nitrous oxide were nulliparous, and over half (51.9%) had expressed an initial preference for "nonmedical birth." The conversion rate to neuraxial blockade was 63.2%, compared to a concurrent institutional rate of 85.1% in women who did not use nitrous oxide. Factors associated with conversion from nitrous oxide to neuraxial blockade were labor induction (aRR=2.0, CI 1.2-3.3) and labor augmentation (aRR=1.7, CI 1.0-2.9). Only a small number of women opted to use nitrous oxide during labor, analgesia was minimal, and most converted to neuraxial analgesia. Women with induced and augmented labors should be counseled about the increased likelihood that they will convert to neuraxial analgesia. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Chronic pain relief after the exposure of nitrous oxide during dental treatment: longitudinal retrospective study.

    Science.gov (United States)

    Mattos Júnior, Francisco Moreira; Mattos, Rafael Villanova; Teixeira, Manoel Jacobsen; Siqueira, Silvia Regina Dowgan Tesseroli de; Siqueira, Jose Tadeu Tesseroli de

    2015-07-01

    The objective was to investigate the effect of nitrous/oxygen in chronic pain. Seventy-seven chronic pain patients referred to dental treatment with conscious sedation with nitrous oxide/oxygen had their records included in this research. Data were collected regarding the location and intensity of pain by the visual analogue scale before and after the treatment. Statistical analysis was performed comparing pre- and post-treatment findings. It was observed a remarkable decrease in the prevalence of pain in this sample (only 18 patients still had chronic pain, p nitrous oxide/oxygen. Nitrous oxide may be a tool to be used in the treatment of chronic pain, and future prospective studies are necessary to understand the underlying mechanisms and the effect of nitrous oxide/oxygen in patients according to the pain diagnosis and other characteristics.

  18. Chronic pain relief after the exposure of nitrous oxide during dental treatment: longitudinal retrospective study

    Directory of Open Access Journals (Sweden)

    Francisco Moreira Mattos Júnior

    2015-07-01

    Full Text Available The objective was to investigate the effect of nitrous/oxygen in chronic pain. Seventy-seven chronic pain patients referred to dental treatment with conscious sedation with nitrous oxide/oxygen had their records included in this research. Data were collected regarding the location and intensity of pain by the visual analogue scale before and after the treatment. Statistical analysis was performed comparing pre- and post-treatment findings. It was observed a remarkable decrease in the prevalence of pain in this sample (only 18 patients still had chronic pain, p < 0.001 and in its intensity (p < 0.001. Patients that needed fewer sessions received higher proportions of nitrous oxide/oxygen. Nitrous oxide may be a tool to be used in the treatment of chronic pain, and future prospective studies are necessary to understand the underlying mechanisms and the effect of nitrous oxide/oxygen in patients according to the pain diagnosis and other characteristics.

  19. Nitrous Oxide During Labor: Maternal Satisfaction Does Not Depend Exclusively on Analgesic Effectiveness.

    Science.gov (United States)

    Richardson, Michael G; Lopez, Brandon M; Baysinger, Curtis L; Shotwell, Matthew S; Chestnut, David H

    2017-02-01

    Evidence on the analgesic effectiveness of nitrous oxide for labor pain is limited. Even fewer studies have looked at patient satisfaction. Although nitrous oxide appears less effective than neuraxial analgesia, it is unclear whether labor analgesic effectiveness is the most important factor in patient satisfaction. We sought to compare the relationship between analgesic effectiveness and patient satisfaction with analgesia in women who delivered vaginally using nitrous oxide, neuraxial analgesia (epidural or combined spinal-epidural [CSE]), or both (neuraxial after a trial of nitrous oxide). A standardized survey was recorded on the first postpartum day for all women who received anesthetic care for labor and delivery. Data were queried for women who delivered vaginally with nitrous oxide and/or neuraxial labor analgesia over a 34-month period in 2011 to 2014. Parturients with complete data for analgesia quality and patient satisfaction were included. Analgesia and satisfaction scores were grouped into 8 to 10 high, 5 to 7 intermediate, and 0 to 4 low. These scores were compared with the use of ordinal logistic regression across 3 groups: nitrous oxide alone, epidural or CSE alone, or nitrous oxide followed by neuraxial (epidural or CSE) analgesia. A total of 6507 women received anesthesia care and delivered vaginally. Complete data were available for 6242 (96%) women; 5261 (81%) chose neuraxial analgesia and 1246 (19%) chose nitrous oxide. Of the latter, 753 (60%) went on to deliver with nitrous oxide alone, and 493 (40%) switched to neuraxial analgesia. Most parturients who received neuraxial analgesia (>90%) reported high analgesic effectiveness. Those who used nitrous oxide alone experienced variable analgesic effectiveness, with only one-half reporting high effectiveness. Among all women who reported poor analgesia effectiveness (0-4; n = 257), those who received nitrous oxide alone were more likely to report high satisfaction (8-10) than women who received

  20. Adverse Cardiovascular Effects of Nitrous Oxide: It is not all about Hyperhomocysteinaemia

    Directory of Open Access Journals (Sweden)

    Ata Mahmoodpoor

    2015-04-01

    Full Text Available Once admired for its supposed safety, nitrous oxide is presently blamed to increase adverse cardiovascular effects through augmenting plasma homocysteine concentrations (1, 2. Hemodynamic alterations following the administration of nitrous oxide are extremely complicated and sometimes contradictory. Enhanced venous return, arterial pressure, pulmonary and systemic vascular resistance, cardiac output, pupillary dilation and diaphoresis occur under nitrous oxide administration consistent with sympathomimetic properties of nitrous oxide (3. Conversely, reductions in arterial pressure are also probable, especially in patients with coronary artery disease. Nitrous oxide can also depress myocardial contractility due to decreased availability of Ca2+ for contractile activation; yet, myocardial relaxation kinetics remains intact (4. In the presence of a volatile anesthetic, nitrous oxide decreases MVO2 (Myocardial oxygen consumption and myocardial O2 extraction which may exacerbate myocardial ischemia during concomitant reductions in arterial pressure in patients with coronary artery disease. Consequently, it could be conjectured that probable adverse cardiovascular effects following nitrous oxide administration are variable and consequent of a multi-variable phenomenon rather than a single variable such as increased levels of homocysteine. Studied purely focusing on the effects of nitrous oxide are difficult to conduct due to the numerous confounding factors. In a study by Myles et al., hyperhomocysteinemia has been introduced as the source of the adverse cardiovascular effects of nitrous oxide. However, in this study, increased inspired oxygen concentrations were used to overcome arterial desaturation (1. Given the fact that a constant volume and flow rates are used throughout the anesthesia in a particular patient, increasing the concentrations of oxygen would be associated with decreased delivered nitrous oxide and volatile anesthetic concentrations

  1. Nitrous oxide for the management of labor pain: a systematic review.

    Science.gov (United States)

    Likis, Frances E; Andrews, Jeffrey C; Collins, Michelle R; Lewis, Rashonda M; Seroogy, Jeffrey J; Starr, Sarah A; Walden, Rachel R; McPheeters, Melissa L

    2014-01-01

    We systematically reviewed evidence addressing the effectiveness of nitrous oxide for the management of labor pain, the influence of nitrous oxide on women's satisfaction with their birth experience and labor pain management, and adverse effects associated with nitrous oxide for labor pain management. We searched the MEDLINE, EMBASE, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases for articles published in English. The study population included pregnant women in labor intending a vaginal birth, birth attendees or health care providers who may be exposed to nitrous oxide during labor, and the fetus/neonate. We identified a total of 58 publications, representing 59 distinct study populations: 2 studies were of good quality, 11 fair, and 46 poor. Inhalation of nitrous oxide provided less effective pain relief than epidural analgesia, but the quality of studies was predominately poor. The heterogeneous outcomes used to assess women's satisfaction with their birth experience and labor pain management made synthesis of studies difficult. Most maternal adverse effects reported in the literature were unpleasant side effects that affect tolerability, such as nausea, vomiting, dizziness, and drowsiness. Apgar scores in newborns whose mothers used nitrous oxide were not significantly different from those of newborns whose mothers used other labor pain management methods or no analgesia. Evidence about occupational harms and exposure was limited. The literature addressing nitrous oxide for the management of labor pain includes few studies of good or fair quality. Further research is needed across all of the areas examined: effectiveness, satisfaction, and adverse effects.

  2. Current use of nitrous oxide in public hospitals in Scandinavian countries.

    Science.gov (United States)

    Husum, B; Stenqvist, O; Alahuhta, S; Sigurdsson, G H; Dale, O

    2013-10-01

    The use of nitrous oxide in modern anaesthesia has been questioned. We surveyed changes in use of nitrous oxide in Scandinavia and its justifications during the last two decades. All 191 departments of anaesthesia in the Scandinavian countries were requested by email to answer an electronic survey in SurveyMonkey. One hundred and twenty-five (64%) of the departments responded; four were excluded. The 121 departments provided 807.520 general anaesthetics annually. The usage of nitrous oxide was reported in 11.9% of cases, ranging from 0.6% in Denmark to 38.6% in Iceland while volatile anaesthetics were employed in 48.9%, lowest in Denmark (22.6%) and highest in Iceland (91.9%). Nitrous oxide was co-administered with volatile anaesthetics in 21.5% of general anaesthetics [2.4% (Denmark) -34.5% (Iceland)]. Use of nitrous oxide was unchanged in five departments (4%), decreasing in 75 (62%) and stopped in 41 (34%). Reasons for decreasing or stopping use of nitrous oxide were fairly uniform in the five countries, the most important being that other agents were 'better', whereas few put weight on its potential risk for increasing morbidity. Decision to stop using nitrous oxide was made by the departments except in four cases. Of 87 maternity wards, nitrous oxide was used in 72, whereas this was the case in 42 of 111 day-surgery units. The use of nitrous oxide has decreased in the Scandinavian countries, apparently because many now prefer other agents. Difference in practices between the five countries were unexpected and apparently not justified on anticipated evidence only. © 2013 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  3. Plant-wide modelling and control of nitrous oxide emissions from wastewater treatment plants

    DEFF Research Database (Denmark)

    Boiocchi, Riccardo

    Nitrous oxide (N2O) is a greenhouses gas with a global warming potential three hundred times stronger than carbon dioxide (CO2). The IPCC report released in 2014 shows that the CO2 equivalents emitted from the wastewater systems are increasing in the last decades. It was also estimated that 14...... the N2O control strategy. In a second step, a comprehensive sensitivity analysis on the BSM2Na was carried out at the aim of extrapolating the main biological mechanisms responsible for N2O emissions. It was found that the ratio between NOB and AOB activity could indicate the accumulation of those...

  4. Nitrous oxide emissions and nitrogen cycling in managed grassland in Southern Hokkaido, Japan

    OpenAIRE

    Shimizu, Mariko; Marutani, Satoru; Desyatkin, Alexey R.; Jin, Tao; Nakano, Kunihiko; Hata, Hiroshi; Hatano, Ryusuke

    2010-01-01

    Nitrous oxide (N2O) emissions were measured and nitrogen (N) budgets were estimated for two years in the fertilizer, manure, control and bare plots established in a reed canary grass (Phalaris arundinacea L.) grassland in Southern Hokkaido, Japan. In the manure plot, beef cattle manure with bark was applied at a rate of 43-44 Mg fresh matter (236-310 kg N) ha^[-1] year^[-1], and a supplement of chemical fertilizer was also added to equalize the application rate of mineral N to that in the fer...

  5. Application of gas-phase chromatography to the study of nitrous oxide retention on soils

    Energy Technology Data Exchange (ETDEWEB)

    Chalamet, A.; Chauchard, J.

    1976-04-26

    The technique of gas chromatography has been used to study the isotherms of nitrous oxide sorption in soil. It was determined by comparing the sorption isotherms for two soils that silicate clay soils were mainly responsible for nitrous oxide sorption. The heat of sorption of nitrous oxide was calculated by the Clapeyron formula and extrapolated from the chromatographs with constants of -5.95 and -6.5 kcal/mole, respectively. The sorption coefficient was higher for particles less than 2 microns than for the total fraction less than 2 millimeters.

  6. Suffocation caused by plastic wrap covering the face combined with nitrous oxide inhalation

    DEFF Research Database (Denmark)

    Leth, Peter Mygind; Astrup, Birgitte Schmidt

    2017-01-01

    as laughing gas, has a euphoric effect and is used as a recreational inhalant drug that can be purchased legally. Deaths caused by recreational nitrous oxide abuse are rare but may occur if used in combination with a plastic bag over the head. This is the first report of suicide by suffocation by external...... with nitrous oxide inhalation, is presented. The case was reviewed based on police, autopsy and hospital reports. A PubMed search for scientific literature related to nitrous oxide abuse and suicide by suffocation was performed and our findings discussed in relation to the scientific literature found...

  7. Wheat leaves emit nitrous oxide during nitrate assimilation.

    Science.gov (United States)

    Smart, D R; Bloom, A J

    2001-07-03

    Nitrous oxide (N(2)O) is a key atmospheric greenhouse gas that contributes to global climatic change through radiative warming and depletion of stratospheric ozone. In this report, N(2)O flux was monitored simultaneously with photosynthetic CO(2) and O(2) exchanges from intact canopies of 12 wheat seedlings. The rates of N(2)O-N emitted ranged from microorganisms on root surfaces and emitted in the transpiration stream. In vitro production of N(2)O by both intact chloroplasts and nitrite reductase, but not by nitrate reductase, indicated that N(2)O produced by leaves occurred during photoassimilation of NO(2)(-) in the chloroplast. Given the large quantities of NO(3)(-) assimilated by plants in the terrestrial biosphere, these observations suggest that formation of N(2)O during NO(2)(-) photoassimilation could be an important global biogenic N(2)O source.

  8. Direct nitrous oxide emissions from rapeseed in Germany

    Science.gov (United States)

    Fuß, Roland; Andres, Monique; Hegewald, Hannes; Kesenheimer, Katharina; Köbke, Sarah; Räbiger, Thomas; Suarez, Teresa; Stichnothe, Heinz; Flessa, Heiner

    2014-05-01

    The production of first generation biofuels has increased over the last decade in Germany. However, there is a strong public and scientific debate concerning ecological impact and sustainability of biofuel production. The EU Renewables Directive requires biofuels to save 35 % of GHG emissions compared to fossil fuels. Starting in 2017, 50 % mitigation of GHG emissions must be achieved. This presents challenges for production of biofuels from rapeseed, which is one of the major renewable resources used for fuel production. Field emissions of nitrous oxide (N2O) and GHG emissions during production of fertilizers contribute strongest to the GHG balance of rapeseed biofuel. Thus, the most promising GHG mitigation option is the optimization of nitrogen fertilization. Since 2012, field trials are conducted on five German research farms to quantify direct GHG emissions. The sites were selected to represent the main rapeseed production regions in Germany as well as climatic regions and soil types. Randomized plot designs were established, which allow monitoring (using manual chambers) impact of fertilization intensity on direct emissions and yield of the typical crop sequence (winter rape - winter wheat - winter barley). The effect of substituting mineral fertilizer with biogas digestate with and without addition of a nitrification inhibitor is also studied. Here we present results from the first cropping season. In 2013, annual direct N2O emissions as well as yield normalized N2O emissions from rape were low. This can be explained with the weather conditions as 2013 was characterized by a cold and long winter with snow until mid spring. As a result, emissions were smaller than predicted by the IPCC emission factors or by the Global Nitrous Oxide Calculator (GNOC). However, emissions still depend on nitrogen input.

  9. Electrochemical reduction of nitrous oxide on La1-xSrxFeO3 perovskites

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent

    2010-01-01

    The electrochemical reduction of nitrous oxide and oxygen has been studied on cone-shaped electrodes of La1-xSrxFeO3-delta perovskites in an all solid state cell, using cyclic voltammetry. It was shown that the activity of the La1-xSrxFeO3-delta perovskites for the electrochemical reduction...... of nitrous oxide mainly depends on the amount of Fe(III) and oxide ion vacancies. The activity of the La1-xSrxFeO3-delta perovskites towards the electrochemical reduction of nitrous oxide is much lower than the activity of the La1-xSrxFeO3-delta perovskites towards the electrochemical reduction of oxygen......, making the possibility of electrochemically reducing nitrous oxide selectively in an exhaust gas containing excess oxygen on this type of materials very doubtful....

  10. Methoxyflurane and Nitrous Oxide as Obstetric Analgesics. I.—A Comparison by Continuous Administration

    Science.gov (United States)

    Jones, Peter L.; Rosen, M.; Mushin, W. W.; Jones, E. V.

    1969-01-01

    Methoxyflurane and nitrous oxide have been compared as obstetric analgesics. The inhaled concentrations of these agents, given continuously, were adjusted by an anaesthetist to maintain each patient at the optimum state between reaction to pain and consciousness. Assessments were made continuously. Though the anaesthetist's assessment showed no difference between the mean results, a greater proportion of the methoxyflurane patients were “satisfactory” for 90–100% of the time than of the nitrous oxide patients, particularly in regard to objective pain relief. The midwives' opinion of those who had “complete” pain relief supported this. Nausea was significantly less among methoxyflurane patients, and vomiting during labour occurred only in patients who had nitrous oxide. It is concluded that nitrous oxide and methoxyflurane given in a continuously adjusted concentration are almost equally effective as obstetric analgesics, though there are certain features which favour methoxyflurane. PMID:4895338

  11. Methoxyflurane and nitrous oxide as obstetric analgesics. I. A comparison by continuous administration.

    Science.gov (United States)

    Jones, P L; Rosen, M; Mushin, W W; Jones, E V

    1969-08-02

    Methoxyflurane and nitrous oxide have been compared as obstetric analgesics. The inhaled concentrations of these agents, given continuously, were adjusted by an anaesthetist to maintain each patient at the optimum state between reaction to pain and consciousness. Assessments were made continuously.Though the anaesthetist's assessment showed no difference between the mean results, a greater proportion of the methoxyflurane patients were "satisfactory" for 90-100% of the time than of the nitrous oxide patients, particularly in regard to objective pain relief. The midwives' opinion of those who had "complete" pain relief supported this. Nausea was significantly less among methoxyflurane patients, and vomiting during labour occurred only in patients who had nitrous oxide. It is concluded that nitrous oxide and methoxyflurane given in a continuously adjusted concentration are almost equally effective as obstetric analgesics, though there are certain features which favour methoxyflurane.

  12. Nitrous oxide and ammonia emissions from injected and broadcast applied dairy slurry

    Science.gov (United States)

    Trade-offs associated with surface application or injection of manure pose important environmental and agronomic concerns. Manure injection can conserve nitrogen (N) by decreasing ammonia volatilization. However, the injection band also creates conditions, which potentially favor nitrous oxide produ...

  13. Nitrous Oxide Fuel Blend-Continuous Operation Lunar Thruster (NOFB-COLT) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Firestar Engineering has developed a set of Nitrous Oxide Fuel Blend monopropellants that are: 1) Non-toxic, 2) Specific Impulse> 310 s, 3) Freezing point <...

  14. MLS/Aura L2 Nitrous Oxide (N2O) Mixing Ratio V003

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2N2O is the EOS Aura Microwave Limb Sounder (MLS) standard product for nitrous oxide derived from radiances measured primarily by the 640 GHz radiometer (Band 12)...

  15. MLS/Aura L2 Nitrous Oxide (N2O) Mixing Ratio V002

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2N2O is the EOS Aura Microwave Limb Sounder (MLS) standard product for nitrous oxide derived from radiances measured primarily by the 640 GHz radiometer (Band 12)...

  16. MLS/Aura Level 2 Nitrous Oxide (N2O) Mixing Ratio V004

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2N2O is the EOS Aura Microwave Limb Sounder (MLS) standard product for nitrous oxide derived from radiances measured primarily by the 640 GHz radiometer (Band 12)...

  17. Effect of nitrous oxide on fentanyl consumption in burned patients undergoing dressing change

    National Research Council Canada - National Science Library

    Arthur Halley Barbosa do Vale; Rogério Luiz da Rocha Videira; David Souza Gomez; Maria José Carvalho Carmona; Sara Yume Tsuchie; Cláudia Flório; Matheus Fachini Vane; Irimar de Paula Posso

    2016-01-01

    BACKGROUND AND OBJECTIVES: Thermal injuries and injured areas management are important causes of pain in burned patients, requiring that these patients are constantly undergoing general anesthesia for dressing change. Nitrous oxide (N2O...

  18. Effect of nitrous oxide on fentanyl consumption in burned patients undergoing dressing change

    National Research Council Canada - National Science Library

    do Vale, Arthur Halley Barbosa; Videira, Rogério Luiz da Rocha; Gomez, David Souza; Carmona, Maria José Carvalho; Tsuchie, Sara Yume; Flório, Cláudia; Vane, Matheus Fachini; Posso, Irimar de Paula

    2016-01-01

    Thermal injuries and injured areas management are important causes of pain in burned patients, requiring that these patients are constantly undergoing general anesthesia for dressing change. Nitrous oxide (N2O...

  19. Nitrous Oxide Fuel Blend-Continuous Operation Lunar Thruster (NOFB-COLT) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose conducting further development for a Nitrous Oxide Fuel Blend (NOFB) propulsion system. Phase I activities will concentrate on a revising a previous 5 lbf...

  20. Data for "Controls on nitrous oxide production and consumption in reservoirs of the Ohio River Basin"

    Data.gov (United States)

    U.S. Environmental Protection Agency — Dissolved oxygen, dissolved nitrous oxide, and water temperature in reservoirs. This dataset is associated with the following publication: Beaulieu , J., C. Nietch ,...

  1. HIRDLS/Aura Level 3 Nitrous Oxide (N2O) Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Nitrous Oxide (N2O) Zonal Fourier Coefficients" version 7 data product (H3ZFCN2O) contains the entire mission (~3 years) of HIRDLS data...

  2. Effectiveness of Nitrous Oxide as a Liquid Injection Thrust Vector Control Fluid Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Nitrous Oxide is proposed as an energetic liquid injection thrust vector control fluid for vehicle attitude control during dynamic vehicle maneuvers. Pulled from the...

  3. Controls on nitrous oxide production and consumption in reservoirs of the Ohio River Basin

    Science.gov (United States)

    Beaulieu, Jake J.; Nietch, Christopher T.; Young, Jade L.

    2015-10-01

    Aquatic ecosystems are a globally significant source of nitrous oxide (N2O), a potent greenhouse gas, but estimates are largely based on studies conducted in streams and rivers with relatively less known about N2O dynamics in reservoirs. Due to long water residence times and high nitrogen (N) loading rates, reservoirs support substantial N processing and therefore may be particularly important sites of N2O production. Predicting N2O emissions from reservoirs is difficult due to complex interactions between microbial N processing in the oxygen-poor hypolimnion and oxygen-rich epilimnion. Here we present the results of a survey of N2O depth profiles in 20 reservoirs draining a broad range of land use conditions in four states in the U.S. Nitrous oxide was supersaturated in the epilimnion of 80% of the reservoirs and was undersaturated in only one, indicating that reservoirs in this region are generally a source of N2O to the atmosphere. Nitrous oxide was undersaturated in the hypolimnion of 10 reservoirs, supersaturated in 9, and transitioned from supersaturation to undersaturation in 1 reservoir that was monitored periodically from midsummer to fall. All reservoirs with a mean hypolimnion nitrate concentration less than 50 µg N L-1 showed evidence of net N2O consumption in the hypolimnion. All reservoirs sampled during lake turnover supported N2O production throughout the water column. These results indicate that N2O dynamics in reservoirs differ widely both among systems and through time but can be predicted based on N and oxygen availability and degree of thermal stratification.

  4. Nitrous Oxide for Treatment-Resistant Major Depression: A Proof-of-Concept Trial.

    Science.gov (United States)

    Nagele, Peter; Duma, Andreas; Kopec, Michael; Gebara, Marie Anne; Parsoei, Alireza; Walker, Marie; Janski, Alvin; Panagopoulos, Vassilis N; Cristancho, Pilar; Miller, J Philip; Zorumski, Charles F; Conway, Charles R

    2015-07-01

    N-methyl-D-aspartate receptor antagonists, such as ketamine, have rapid antidepressant effects in patients with treatment-resistant depression (TRD). We hypothesized that nitrous oxide, an inhalational general anesthetic and N-methyl-D-aspartate receptor antagonist, may also be a rapidly acting treatment for TRD. In this blinded, placebo-controlled crossover trial, 20 patients with TRD were randomly assigned to 1-hour inhalation of 50% nitrous oxide/50% oxygen or 50% nitrogen/50% oxygen (placebo control). The primary endpoint was the change on the 21-item Hamilton Depression Rating Scale (HDRS-21) 24 hours after treatment. Mean duration of nitrous oxide treatment was 55.6 ± 2.5 (SD) min at a median inspiratory concentration of 44% (interquartile range, 37%-45%). In two patients, nitrous oxide treatment was briefly interrupted, and the treatment was discontinued in three patients. Depressive symptoms improved significantly at 2 hours and 24 hours after receiving nitrous oxide compared with placebo (mean HDRS-21 difference at 2 hours, -4.8 points, 95% confidence interval [CI], -1.8 to -7.8 points, p = .002; at 24 hours, -5.5 points, 95% CI, -2.5 to -8.5 points, p nitrous oxide and placebo, p nitrous oxide compared with one patient (5%) and none after placebo (odds ratio for response, 4.0, 95% CI, .45-35.79; OR for remission, 3.0, 95% CI, .31-28.8). No serious adverse events occurred; all adverse events were brief and of mild to moderate severity. This proof-of-concept trial demonstrated that nitrous oxide has rapid and marked antidepressant effects in patients with TRD. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  5. Influence of nitrous oxide anesthesia, B-vitamins, and MTHFR gene polymorphisms on perioperative cardiac events: the vitamins in nitrous oxide (VINO) randomized trial.

    Science.gov (United States)

    Nagele, Peter; Brown, Frank; Francis, Amber; Scott, Mitchell G; Gage, Brian F; Miller, J Philip

    2013-07-01

    Nitrous oxide causes an acute increase in plasma homocysteine that is more pronounced in patients with the methylenetetrahydrofolate reductase (MTHFR) C677T or A1298C gene variant. In this randomized controlled trial, the authors sought to determine whether patients carrying the MTHFR C677T or A1298C variant had a higher risk for perioperative cardiac events after nitrous oxide anesthesia and whether this risk could be mitigated by B-vitamins. The authors randomized adult patients with cardiac risk factors undergoing noncardiac surgery, to receive nitrous oxide plus intravenous B-vitamins before and after surgery, or to nitrous oxide and placebo. Serial cardiac biomarkers and 12-lead electrocardiograms were obtained. The primary study endpoint was the incidence of myocardial injury, as defined by cardiac troponin I increase within the first 72 h after surgery. A total of 500 patients completed the trial. Patients who were homozygous for either MTHFR C677T, or A1298C gene variant (n=98; 19.6%) had no increased rate of postoperative cardiac troponin I increase compared with wild-type and heterozygous patients (11.2 vs. 14.0%; relative risk 0.96; 95% CI, 0.85-1.07; P=0.48). B-vitamins blunted the rise in homocysteine, but had no effect on cardiac troponin I increase compared with patients receiving placebo (13.2 vs. 13.6%; relative risk 1.02; 95% CI 0.78 to 1.32; P=0.91). Neither MTHFR C677T and A1298C gene variant, nor acute homocysteine increase are associated with perioperative cardiac troponin increase after nitrous oxide anesthesia. B-vitamins blunt nitrous oxide-induced homocysteine increase but have no effect on cardiac troponin I increase.

  6. Initiating Intrapartum Nitrous Oxide in an Academic Hospital: Considerations and Challenges.

    Science.gov (United States)

    Migliaccio, Laura; Lawton, Robyn; Leeman, Lawrence; Holbrook, Amanda

    2017-05-01

    A 50%-50% mixture of nitrous oxide and oxygen has long been used for managing pain during labor in many countries, but only recently has this intrapartum analgesic technique become popular in the United States. Nitrous oxide is considered minimal sedation and a safe pain management alternative. Many facilities are now interested in providing laboring women this analgesic option. The process of establishing use of nitrous oxide in a large institution can be complicated and may seem daunting. This brief report describes the challenges that occurred during the process of initiating nitrous oxide for pain management during childbirth at an academic medical center and discusses various committee roles. Nurses at the University of New Mexico Hospital now directly oversee the administration of nitrous oxide to women in labor in accordance to an established guideline. Despite limited available research, the guideline also allows offering nitrous oxide as a pain management technique for women with opioid dependence. Key components of the guideline and specifics related to education, cost, and safety are reviewed. © 2017 by the American College of Nurse-Midwives.

  7. Establishment and calibration of consensus process model for nitrous oxide dynamics in water quality engineering

    DEFF Research Database (Denmark)

    Domingo-Felez, Carlos

    that enhance cost and energy efficiency in BNR, while maintaining effluent quali-ty. Now, increasing attention is placed on direct emissions of nitrous oxide (N2O) as by-product of BNR; N2O is a greenhouse gas (GHG) with a high warming potential and also an ozone depleting chemical compound. Several N2O...... consumption (endogenous activity, nitrite and ammonium oxidation) and N2O production (NN, ND and HD pathway contributions). To estimate parameters of the N2O model a rigorous procedure is presented as a case study. The calibrated model predicts the NO and N2O dynamics at varying ammonium, nitrite...... and dissolved oxygen levels in two independent systems: (a) an AOB-enriched biomass and (b) activated sludge (AS) mixed liquor biomass. A total of ten (a) and seventeen (b) parameters are identified with high accuracy (coefficients of variation

  8. Concentrations of methoxyflurane and nitrous oxide in veterinary operating rooms

    Energy Technology Data Exchange (ETDEWEB)

    Ward, G.S.; Byland, R.R.

    1982-02-01

    The surgical rooms of 14 private veterinary practices were monitored to determined methoxyflurane (MOF) concentrations during surgical procedure under routine working conditions. The average room volume for these 14 rooms was 29 m3. The average MOF value for all rooms was 2.3 ppm, with a range of 0.7 to 7.4 ppm. Four of the 14 rooms exceeded the maximum recommended concentration of 2 ppm. Six rooms which had 6 or more air changes/hr averaged 1.1 ppm, whereas 8 rooms with less than 6 measurable air changes/hr averaged 3.2 ppm. Operating rooms that had oxygen flows of more than 1,000 cm3/min averaged 4.4 ppm, whereas those with flows of less than 1,000 cm3/min averaged 1.5 ppm. The average time spent during a surgical procedure using MOF, for all 14 facilities, was 2 hours. Nitrous oxide (N/sub 2/O) concentrations were determined in 4 veterinary surgical rooms. The average N/sub 2/O concentration for 3 rooms without waste anesthetic gas scavenging was 138 ppm. Concentration of N/sub 2/O in the waste anesthetic gas-scavenged surgical room was 14 ppm, which was below the maximum recommended concentration of 25 ppm.

  9. Nitrous oxide production associated with coastal marine invertebrates

    DEFF Research Database (Denmark)

    Heisterkamp, Ines Maria; Schramm, Andreas; de Beer, Dirk

    2010-01-01

    Several freshwater and terrestrial invertebrate species emit the greenhouse gas nitrous oxide (N2O). The N2O production associated with these animals was ascribed to incomplete denitrification by ingested sediment or soil bacteria. The present study shows that many marine invertebrates also emit N2......O at substantial rates. A total of 19 invertebrate species collected in the German Wadden Sea and in Aarhus Bay, Denmark, and 1 aquacultured shrimp species were tested for N2O emission. Potential N2O emission rates ranged from 0 to 1.354 nmol ind.–1 h–1, with an average rate of 0.320 nmol ind.–1 h–1...... with an experimentally cleaned shell. Thus, the N2O production associated with marine invertebrates is apparently not due to gut denitrification in every species, but may also result from microbial activity on the external surfaces of animals. The high abundance and potential N2O emission rates of many marine...

  10. Nitrous oxide emissions from clover in the Mediterranean environment

    Directory of Open Access Journals (Sweden)

    Iride Volpi

    2016-06-01

    Full Text Available Introducing nitrogen N2-fixing crops into cereal-based crop rotations reduces N-fertiliser use and may mitigate soil emissions of nitrous oxide (N2O. However, the effect of the cultivation of N2-fixing crops on N2O emissions is still not well understood. N2O from N2-fixing crops can be emitted in two ways: during biological N2 fixation itself and when legume residues are returned to the soil. A field trial was carried out on clover (Trifolium squarrosum Savi to test the role of leguminous crops on N2O emissions in the Mediterranean environment. Monitoring was performed from December 2013 to September 2014. Cumulated N-N2O fluxes were calculated for the growing season (Phase 1 and the post-harvest period (Phase 2 in order to assess the importance of each phase. Our results did not show statistically significant differences between the two phases in term of contribution to the total cumulative N-N2O emissions, in fact Phase 1 and Phase 2 accounted respectively for 43 and 57% of the total.

  11. UK emissions of the greenhouse gas nitrous oxide

    Science.gov (United States)

    Skiba, U.; Jones, S. K.; Dragosits, U.; Drewer, J.; Fowler, D.; Rees, R. M.; Pappa, V. A.; Cardenas, L.; Chadwick, D.; Yamulki, S.; Manning, A. J.

    2012-01-01

    Signatories of the Kyoto Protocol are obliged to submit annual accounts of their anthropogenic greenhouse gas emissions, which include nitrous oxide (N2O). Emissions from the sectors industry (3.8 Gg), energy (14.4 Gg), agriculture (86.8 Gg), wastewater (4.4 Gg), land use, land-use change and forestry (2.1 Gg) can be calculated by multiplying activity data (i.e. amount of fertilizer applied, animal numbers) with simple emission factors (Tier 1 approach), which are generally applied across wide geographical regions. The agricultural sector is the largest anthropogenic source of N2O in many countries and responsible for 75 per cent of UK N2O emissions. Microbial N2O production in nitrogen-fertilized soils (27.6 Gg), nitrogen-enriched waters (24.2 Gg) and manure storage systems (6.4 Gg) dominate agricultural emission budgets. For the agricultural sector, the Tier 1 emission factor approach is too simplistic to reflect local variations in climate, ecosystems and management, and is unable to take into account some of the mitigation strategies applied. This paper reviews deviations of observed emissions from those calculated using the simple emission factor approach for all anthropogenic sectors, briefly discusses the need to adopt specific emission factors that reflect regional variability in climate, soil type and management, and explains how bottom-up emission inventories can be verified by top-down modelling. PMID:22451103

  12. Influence of nitrous oxide anesthesia, B-vitamins, and MTHFR gene polymorphisms on perioperative cardiac events: the vitamins in nitrous oxide (VINO) randomized trial

    National Research Council Canada - National Science Library

    Nagele, Peter; Brown, Frank; Francis, Amber; Scott, Mitchell G; Gage, Brian F; Miller, J Philip

    2013-01-01

    ...) C677T or A1298C gene variant. In this randomized controlled trial, the authors sought to determine whether patients carrying the MTHFR C677T or A1298C variant had a higher risk for perioperative cardiac events after nitrous oxide...

  13. Suffocation caused by plastic wrap covering the face combined with nitrous oxide inhalation.

    Science.gov (United States)

    Leth, Peter Mygind; Astrup, Birgitte Schmidt

    2017-09-01

    Suicide using a combination of a plastic bag over the head and inhalation of a non-irritating gas, such as helium, argon or nitrogen, has been reported in the literature. Here an unusual suicide method in a 17-year old man by suffocation from covering the face with household plastic wrap, combined with nitrous oxide inhalation, is presented. The case was reviewed based on police, autopsy and hospital reports. A PubMed search for scientific literature related to nitrous oxide abuse and suicide by suffocation was performed and our findings discussed in relation to the scientific literature found. The deceased was a 17-year old man who was found with the nose and mouth closed with a piece of kitchen plastic wrap. The plastic wrap had been removed prior to autopsy. Autopsy findings were suggestive of asphyxia, but were otherwise negative. Nitrous oxide was detected in the brain and lung tissue with headspace-gas chromatography-mass spectrometry (headspace-GCMS). The cause of death was assumed to be suffocation caused by plastic wrap covering the face, combined with nitrous oxide inhalation. Suicide was suspected because of a history of depression for several months. Nitrous oxide, also known as laughing gas, has a euphoric effect and is used as a recreational inhalant drug that can be purchased legally. Deaths caused by recreational nitrous oxide abuse are rare but may occur if used in combination with a plastic bag over the head. This is the first report of suicide by suffocation by external obstruction combined with nitrous oxide inhalation.

  14. Oxidative DNA damage and oxidative stress in subjects occupationally exposed to nitrous oxide (N(2)O).

    Science.gov (United States)

    Wrońska-Nofer, Teresa; Nofer, Jerzy-Roch; Jajte, Jolanta; Dziubałtowska, Elżbieta; Szymczak, Wiesław; Krajewski, Wojciech; Wąsowicz, Wojciech; Rydzyński, Konrad

    2012-03-01

    Occupational exposure to nitrous oxide (N(2)O) and/or halogenated hydrocarbons has been suggested to induce damage of genetic material, but the underlying mechanisms remain obscure. This study investigated the role of oxidative processes in the genotoxicity associated with exposure to waste anaesthetic gases. The study was performed in 36 female nurses and in 36 unexposed female health care workers matched for age and employment duration. Genotoxic effects were examined by Comet test modification employing formamidopyrimidine glycosylase (FPG) that allows assessment of oxidative DNA damage. Reactive oxygen species (ROS) in leukocytes were investigated by fluorescence spectroscopy with 2',7'-dichlorofluorescin diacetate. Oxidative stress markers including 8-iso-prostaglandin F(2α) (8-iso-PGF(2α)), thiobarbituric acid-reacive substances (TBARS), α-tocopherol, and glutathione peroxidise (GPX) activity were measured immuno- or colorimetrically. N(2)O, sevoflurane and isoflurane were monitored by gas chromatography and mass spectrometry. The study documents for the first time the positive correlation between the oxidative DNA damage and the N(2)O levels in the ambient air. By contrast, no association was observed between genotoxic effects and sevoflurane or isoflurane. In addition, ROS generation and plasma and urine concentrations of TBARS and 8-iso-PGF(2α), respectively, were elevated, while GPX activity was reduced in nurses exposed to waste anaesthetic gases. Path analysis pointed to a causal relationship between N(2)O exposure, oxidative stress and DNA damage. Occupational exposure to N(2)O is associated with increased oxidative DNA damage and the level of exposure plays a critical role in this regard. Increased oxidative stress may represent a mechanistic link between chronic N(2)O exposure and genotoxicity. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Community Composition of Nitrous Oxide-Related Genes in Salt Marsh Sediments Exposed to Nitrogen Enrichment

    Directory of Open Access Journals (Sweden)

    John H. Angell

    2018-02-01

    Full Text Available Salt marshes provide many key ecosystem services that have tremendous ecological and economic value. One critical service is the removal of fixed nitrogen from coastal waters, which limits the negative effects of eutrophication resulting from increased nutrient supply. Nutrient enrichment of salt marsh sediments results in higher rates of nitrogen cycling and, commonly, a concurrent increase in the flux of nitrous oxide, an important greenhouse gas. Little is known, however, regarding controls on the microbial communities that contribute to nitrous oxide fluxes in marsh sediments. To address this disconnect, we generated profiles of microbial communities and communities of micro-organisms containing specific nitrogen cycling genes that encode several enzymes (amoA, norB, nosZ related to nitrous oxide flux from salt marsh sediments. We hypothesized that communities of microbes responsible for nitrogen transformations will be structured by nitrogen availability. Taxa that respond positively to high nitrogen inputs may be responsible for the elevated rates of nitrogen cycling processes measured in fertilized sediments. Our data show that, with the exception of ammonia-oxidizing archaea, the community composition of organisms involved in the production and consumption of nitrous oxide was altered under nutrient enrichment. These results suggest that previously measured rates of nitrous oxide production and consumption are likely the result of changes in community structure, not simply changes in microbial activity.

  16. Changes in heart rate variability during anaesthesia induction using sevoflurane or isoflurane with nitrous oxide.

    Science.gov (United States)

    Nishiyama, Tomoki

    2016-01-01

    The purpose of this study was to compare cardiac sympathetic and parasympathetic balance using heart rate variability (HRV) during induction of anaesthesia between sevoflurane and isoflurane in combination with nitrous oxide. 40 individuals aged from 30 to 60 years, scheduled for general anaesthesia were equally divided into sevoflurane or isoflurane groups. After 100% oxygen inhalation for a few minutes, anaesthesia was induced with nitrous oxide 3 L min-1, oxygen 3 L min-1 and sevoflurane or isoflurane. Sevoflurane or isoflurane concentration was increased by 0.5% every 2 to 3 breaths until 5% was attained for sevoflurane, or 3% for isoflurane. Vecuronium was administered to facilitate tracheal intubation. After intubation, sevoflurane was set to 2% while isoflurane was set to 1% with nitrous oxide with oxygen (1:1) for 5 min. Both sevoflurane and isoflurane provoked a decrease in blood pressure, total power, the low frequency component (LF), and high frequency component (HF) of HRV. Although the heart rate increased during isoflurane anaesthesia, it decreased under sevoflurane. The power of LF and HF also decreased in both groups. LF was higher in the isoflurane group while HF was higher in the sevoflurane group. The LF/HF ratio increased transiently in the isoflurane group, but decreased in the sevoflurane group. Anaesthesia induction with isoflurane-nitrous oxide transiently increased cardiac sympathetic activity, while sevoflurane-nitrous oxide decreased both cardiac sympathetic and parasympathetic activities. The balance of cardiac parasympathetic/sympathetic activity was higher in sevoflurane anaesthesia.

  17. Nitrous oxide and methane emissions during storage of dewatered digested sewage sludge.

    Science.gov (United States)

    Willén, Agnes; Rodhe, Lena; Pell, Mikael; Jönsson, Håkan

    2016-12-15

    This study investigated the effect on greenhouse gas emissions during storage of digested sewage sludge by using a cover during storage or applying sanitisation measures such as thermophilic digestion or ammonia addition. In a pilot-scale storage facility, nitrous oxide and methane emissions were measured on average twice monthly for a year, using a closed chamber technique. The thermophilically digested sewage sludge (TC) had the highest cumulative emissions of nitrous oxide (1.30% of initial total N) followed by mesophilically digested sewage sludge stored without a cover (M) (0.34%) and mesophilically digested sewage sludge stored with a cover (MC) (0.19%). The mesophilically digested sewage sludge sanitised with ammonia and stored with a cover (MAC) showed negligible cumulative emissions of nitrous oxide. Emissions of methane were much lower from TC and MAC than from M and MC. These results indicate that sanitisation by ammonia treatment eliminates the production of nitrous oxide and reduces methane emissions from stored sewage sludge, and that thermophilic digestion has the potential to reduce the production of methane during storage compared with mesophilic digestion. The results also indicate a tendency for lower emissions of nitrous oxide and higher emissions of methane from covered sewage sludge compared with non-covered. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Nitrous oxide emissions in a membrane bioreactor treating saline wastewater contaminated by hydrocarbons.

    Science.gov (United States)

    Mannina, Giorgio; Cosenza, Alida; Di Trapani, Daniele; Laudicina, Vito Armando; Morici, Claudia; Ødegaard, Hallvard

    2016-11-01

    The joint effect of wastewater salinity and hydrocarbons on nitrous oxide emission was investigated. The membrane bioreactor pilot plant was operated with two phases: i. biomass acclimation by increasing salinity from 10gNaClL(-1) to 20gNaClL(-1) (Phase I); ii. hydrocarbons dosing at 20mgL(-1) with a constant salt concentration of 20gNaClL(-1) (Phase II). The Phase I revealed a relationship between nitrous oxide emissions and salinity. During the end of the Phase I, the activity of nitrifiers started to recover, indicating a partial acclimatization. During the Phase II, the hydrocarbon shock induced a temporary inhibition of the biomass with the suppression of nitrous oxide emissions. The results revealed that the oxic tank was the major source of nitrous oxide emission, likely due to the gas stripping by aeration. The joint effect of salinity and hydrocarbons was found to be crucial for the production of nitrous oxide. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Nitrous oxide provides safe and effective analgesia for minor paediatric procedures--a systematic review.

    Science.gov (United States)

    Pedersen, Rie S; Bayat, Allan; Steen, Nick Phaff; Jacobsson, Marie-Laure Bouchy

    2013-06-01

    Pain and distress during minor hospital-related procedures is a familiar problem in many children. Inadequate relief of children's procedural pain and distress not only affects the experience of the children and their parents, but also adversely impacts procedural success. We aimed to review the safety and efficacy of nitrous oxide during brief, but painful paediatric procedures and to compare nitrous oxide with some of the commonly used pharmacological and non-pharmacological treatments for relieving anxiety and mild to moderate pain in Denmark. We searched MEDLINE (PubMed) and the Cochrane Database of Systematic Reviews with the MeSH term nitrous oxide combined with midazolam, surgical procedures minor, analgesia or conscious sedation. The references in the articles acquired that were not found in the MEDLINE search were further investigated. Only articles written in English and published after 1980 were included to ensure optimal data collection. Nitrous oxide is an effective sedative/analgesic for mildly to moderately painful paediatric procedures. Furthermore, it is safely administrated, particularly for short procedures (Nitrous oxide is a safe and effective method to achieve analgesia and sedation during minor, but painful procedures. It can be safely administered by a dedicated staff member. This helpful method is still underused in Denmark, and we believe that it could be an alternative or the first choice of treatment in emergency and paediatric departments.

  20. Sedation with nitrous oxide compared with no sedation during catheterization for urologic imaging in children

    Energy Technology Data Exchange (ETDEWEB)

    Zier, Judith L. [Children' s Hospitals and Clinics of Minnesota, Pediatric Critical Care, Minneapolis, MN (United States); Children' s Respiratory and Critical Care Specialists, Minneapolis, MN (United States); Kvam, Kathryn A. [University of Michigan Medical School, Ann Arbor, MI (United States); Kurachek, Stephen C. [Children' s Hospitals and Clinics of Minnesota, Pediatric Critical Care, Minneapolis, MN (United States); Finkelstein, Marsha [Children' s Hospitals and Clinics of Minnesota, Center for Care Innovation and Research, Minneapolis, MN (United States)

    2007-07-15

    Various strategies to mitigate children's distress during voiding cystourethrography (VCUG) have been described. Sedation with nitrous oxide is comparable to that with oral midazolam for VCUG, but a side-by-side comparison of nitrous oxide sedation and routine care is lacking. The effects of sedation/analgesia using 70% nitrous oxide and routine care for VCUG and radionuclide cystography (RNC) were compared. A sample of 204 children 4-18 years of age scheduled for VCUG or RNC with sedation or routine care were enrolled in this prospective study. Nitrous oxide/oxygen (70%/30%) was administered during urethral catheterization to children in the sedated group. The outcomes recorded included observed distress using the Brief Behavioral Distress Score, self-reported pain, and time in department. The study included 204 patients (99 nonsedated, 105 sedated) with a median age of 6.3 years (range 4.0-15.2 years). Distress and pain scores were greater in nonsedated than in sedated patients (P < 0.001). Time in department was longer in the sedated group (90 min vs. 30 min); however, time from entry to catheterization in a non-imaging area accounted for most of the difference. There was no difference in radiologic imaging time. Sedation with nitrous oxide is effective in reducing distress and pain during catheterization for VCUG or RNC in children. (orig.)

  1. Nitrous Oxides Ozone Destructiveness Under Different Climate Scenarios

    Science.gov (United States)

    Kanter, David R.; McDermid, Sonali P.

    2016-01-01

    Nitrous oxide (N2O) is an important greenhouse gas and ozone depleting substance as well as a key component of the nitrogen cascade. While emissions scenarios indicating the range of N2O's potential future contributions to radiative forcing are widely available, the impact of these emissions scenarios on future stratospheric ozone depletion is less clear. This is because N2O's ozone destructiveness is partially dependent on tropospheric warming, which affects ozone depletion rates in the stratosphere. Consequently, in order to understand the possible range of stratospheric ozone depletion that N2O could cause over the 21st century, it is important to decouple the greenhouse gas emissions scenarios and compare different emissions trajectories for individual substances (e.g. business-as-usual carbon dioxide (CO2) emissions versus low emissions of N2O). This study is the first to follow such an approach, running a series of experiments using the NASA Goddard Institute for Space Sciences ModelE2 atmospheric sub-model. We anticipate our results to show that stratospheric ozone depletion will be highest in a scenario where CO2 emissions reductions are prioritized over N2O reductions, as this would constrain ozone recovery while doing little to limit stratospheric NOx levels (the breakdown product of N2O that destroys stratospheric ozone). This could not only delay the recovery of the stratospheric ozone layer, but might also prevent a return to pre-1980 global average ozone concentrations, a key goal of the international ozone regime. Accordingly, we think this will highlight the importance of reducing emissions of all major greenhouse gas emissions, including N2O, and not just a singular policy focus on CO2.

  2. Diurnality of soil nitrous oxide (N2O) emissions

    Science.gov (United States)

    Gelfand, I.; Moyer, R.; Poe, A.; Pan, D.; Abraha, M.; Chen, J.; Zondlo, M. A.; Robertson, P.

    2015-12-01

    Soil emissions of nitrous oxide (N2O) are important contributors to the greenhouse gas balance of the atmosphere. Agricultural soils contribute ~65% of anthropogenic N2O emissions. Understanding temporal and spatial variability of N2O emissions from agricultural soils is vital for closure of the global N2O budget and the development of mitigation opportunities. Recent studies have observed higher N2O fluxes during the day and lower at night. Understanding the mechanisms of such diurnality may have important consequences for our understanding of the N cycle. We tested the hypothesis that diurnal cycles are driven by root carbon exudes that stimulate denitrification and therefore N2O production. Alternatively, we considered that the cycle could result from higher afternoon temperatures that accelerate soil microbial activity. We removed all plants from a corn field plot and left another plot untouched. We measured soil N2O emissions in each plot using a standard static chamber technique throughout the corn growing season. And also compared static chamber results to ecosystem level N2O emissions as measured by eddy covariance tower equipped with an open-path N2O sensor. We also measured soil and air temperatures and soil water and inorganic N contents. Soil N2O emissions followed soil inorganic N concentrations and in control plot chambers ranged from 10 μg N m-2 hr-1 before fertilization to 13×103 after fertilization. We found strong diurnal cycles measured by both techniques with emissions low during night and morning hours and high during the afternoon. Corn removal had no effect on diurnality, but had a strong effect on the magnitude of soil N2O emissions. Soil temperature exhibited a weak correlation with soil N2O emissions and could not explain diurnal patterns. Further studies are underway to explore additional mechanisms that might contribute to this potentially important phenomena.

  3. Causes of nitrous oxide contamination in operating rooms.

    Science.gov (United States)

    Kanmura, Y; Sakai, J; Yoshinaka, H; Shirao, K

    1999-03-01

    To reduce the ambient concentration of waste anesthetic agents, exhaust gas scavenging systems are standard in almost all operating rooms. The incidence of contamination and the factors that may increase the concentrations of ambient anesthetic gases have not been evaluated fully during routine circumstances, however. Concentrations of nitrous oxide (N2O) in ambient air were monitored automatically in 10 operating rooms in Kagoshima University Hospital from January to March 1997. Ambient air was sampled automatically from each operating room, and the concentrations of N2O were analyzed every 22 min by an infrared spectrophotometer. The output of the N2O analyzer was integrated electronically regarding time, and data were displayed on a monitor in the administrative office for anesthesia supervisors. A concentration of N2O > 50 parts per million was regarded as abnormally high and was displayed with an alarm signal. The cause of the high concentration of N2O was then sought. During the 3-month investigation, N2O was used in 402 cases. Abnormally high concentrations of N2O were detected at some time during 104 (25.9%) of those cases. The causes were mask ventilation (42 cases, 40.4% of detected cases), unconnected scavenging systems (20 cases, 19.2%), leak around uncuffed pediatric endotracheal tube (13 cases, 12.5%), equipment leakage (12 cases, 11.5%), and others (17 cases, 16.4%). N2O contamination was common during routine circumstances in our operating rooms. An unconnected scavenging system led to the highest concentrations of N2O recorded. Proper use of scavenging systems is necessary if contamination by anesthetic gas is to be limited.

  4. Nitrous oxide emissions from irrigated cotton in north eastern Australia

    Science.gov (United States)

    Grace, P.; Rowlings, D.; Weier, K.; Rochester, I.; Kiese, R.; Butterbach-Bahl, K.

    2009-04-01

    Cotton is one of many agricultural industries in Australia heavily reliant on nitrogenous fertilizers and water storages to maintain high levels of production. Cotton-based farming systems are therefore labelled as potentially high-risk agricultural systems with respect to gaseous losses of nitrogen to the atmosphere. The on-farm study was undertaken at Dalby in the Darling Downs region of Queensland in north eastern Australia. The field was furrow irrigated and had been under continuous cotton (with winter bare fallow) for 10 years. The block was conventionally tilled, with a spraying regime typical for cotton production in this area. The black clay (with a surface clay content of 68%) and soil organic carbon content (0-10 cm) of 1.0% and a pH of 8.5, is typical of the region. During the the 2006/07 season, soil water (0-50 cm with Enviroscan), mineral nitrogen (0-10 cm) and crop production data was also collected to develop accurate models for predicting greenhouse gas emissions as a function of key chemical, physical and biological processes and specific management events. The 2006/07 experiment also attempted to directly measure the specific losses of N2O and N2 from a single application of N fertiliser using 15N isotopically labelled urea. The automated greenhouse gas measuring system (developed by Butterbach-Bahl et al.) consists of six chambers connected to sequential sampling unit, a gas chromatograph (equipped with both electron capture and flame ionization detectors for nitrous oxide and methane analysis respectively), and a Licor for carbon dioxide. To meet the demand for high mobility, the sample acquisition and analysis system is trailer mounted. During a normal sampling period, the chambers were closed for 90 minutes (unless temperatures within the chambers exceeded 55oC). The sampling program ensured that that a single gas sample was drawn back from each chamber every 20 minutes. To facilitate 15N gas sampling, Swagelok T-pieces were inserted into

  5. Low nitrous oxide production in intermittent-feed high performance nitritating reactors

    DEFF Research Database (Denmark)

    Su, Qingxian; Jensen, Malene M.; Smets, Barth F.

    Nitrous oxide (N2O) production from autotrophic nitrogen removal processes, especially nitritating systems, is of growing concern. N2O dynamics were characterized and N2O production factors were quantified in two lab-scale intermittent-feed nitritating SBRs. 93 ± 14% of the oxidized ammonium...

  6. Nitrous oxide emissions from Phragmites australis-dominated zones in a shallow lake.

    Science.gov (United States)

    Yang, Zhifeng; Zhao, Ying; Xia, Xinghui

    2012-07-01

    Nitrous oxide (N(2)O) emissions from Phragmites australis (reed)--dominated zones in Baiyangdian Lake, the largest shallow lake of Northern China, were investigated under different hydrological conditions with mesocosm experiments during the growing season of reeds. The daily and monthly N(2)O emissions were positively correlated with air temperature and the variation of aboveground biomass of reeds (p effect of hydrological conditions, N(2)O emissions from the aquatic-terrestrial ecotone were 9.4-26.1% higher than the submerged zone, inferring that the variation of water level would increase N(2)O emissions. The annual N(2)O emission from Baiyangdian Lake was estimated to be about 114.2 t. This study suggested that N(2)O emissions from shallow lakes might be accelerated by the climate change as it has increased air temperature and changed precipitation, causing the variation of water level. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Nitrous oxide emissions from a beech forest floor measured by eddy covariance and soil enclosure techniques

    DEFF Research Database (Denmark)

    Pihlatie, M.; Rinne, J.; Ambus, P.

    2005-01-01

    Spring time nitrous oxide (N2O) emissions from an old beech (Fagus sylvatica L.) forest were measured with eddy covariance (EC) and chamber techniques. The aim was to obtain information on the spatial and temporal variability in N2O emissions and link the emissions to soil environmental parameters...... the first week of May when the trees were leafing and the soil moisture content was at its highest. If chamber techniques are used to estimate ecosystem level N2O emissions from forest soils, placement of the chambers should be considered carefully to cover the spatial variability in the soil N2O emissions....... Mean N2O fluxes over the five week measurement period were 5.6 +/- 1.1, 10 +/- 1 and 16 +/- 11 mu g N m(-2) h(-1) from EC, automatic chamber and manual chambers, respectively. High temporal variability characterized the EC fluxes in the trunk-space. To reduce this variability, resulting mostly from...

  8. Methoxyflurane and nitrous oxide as obstetric analgesics. II. A comparison by self-administered intermittent inhalation.

    Science.gov (United States)

    Jones, P L; Rosen, M; Mushin, W W; Jones, E V

    1969-08-02

    Methoxyflurane (0.35%) in air and nitrous oxide/oxygen (50%/50%) self-administered intermittently in the usual way have been compared as analgesics for labour. There were 25 patients in each group. Objective assessment by an anaesthetist showed that methoxyflurane is the more effective analgesic, and this was supported by the opinion of the multiparae. Nausea and vomiting were significantly less with methoxyflurane. Fifty per cent. nitrous oxide in oxygen given intermittently does not appear to be the best analgesic concentration. Nevertheless, since a considerable variation in sensitivity exists, it would probably be unwise to consider the introduction of higher concentrations for use by unsupervised midwives.This trial confirms the predictions made by us using a method for screening inhalational analgesics, in which methoxyflurane and nitrous oxide were given continuously.

  9. Methane and nitrous oxide emissions from animal manure management, 1990 - 2003 - Background document on the calculation method for the Dutch National Inventory Report

    NARCIS (Netherlands)

    Hoek KW van der; Schijndel MW van; MNP; LVM

    2006-01-01

    Since 2005 the Netherlands has used a new country-specific method to calculate the methane and nitrous oxide emissions from animal manure management. Compared to the default methods provided by the Intergovernmental Panel on Climate Change, this method has led to a more realistic estimate of the

  10. Investigating the effects of nitrous oxide sedation on frontal-parietal interactions.

    Science.gov (United States)

    Ryu, Ji-Ho; Kim, Pil-Jong; Kim, Hong-Gee; Koo, Yong-Seo; Shin, Teo Jeon

    2017-06-09

    Although functional connectivity has received considerable attention in the study of consciousness, few studies have investigated functional connectivity limited to the sedated state where consciousness is maintained but impaired. The aim of the present study was to investigate changes in functional connectivity of the parietal-frontal network resulting from nitrous oxide-induced sedation, and to determine the neural correlates of cognitive impairment during consciousness transition states. Electroencephalography was acquired from healthy adult patients who underwent nitrous oxide inhalation to induce cognitive impairment, and was analyzed using Granger causality (GC). Periods of awake, sedation and recovery for GC between frontal and parietal areas in the delta, theta, alpha, beta, gamma and total frequency bands were obtained. The Friedman test with post-hoc analysis was conducted for GC values of each period for comparison. As a sedated state was induced by nitrous oxide inhalation, power in the low frequency band showed increased activity in frontal regions that was reversed with discontinuation of nitrous oxide. Feedback and feedforward connections analyzed in spectral GC were changed differently in accordance with EEG frequency bands in the sedated state by nitrous oxide administration. Calculated spectral GC of the theta, alpha, and beta frequency regions in the parietal-to-frontal direction was significantly decreased in the sedated state while spectral GC in the reverse direction did not show significant change. Frontal-parietal functional connectivity is significantly affected by nitrous oxide inhalation. Significantly decreased parietal-to-frontal interaction may induce a sedated state. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Inhalation analgesia with nitrous oxide versus other analgesic techniques in hysteroscopic polypectomy: a pilot study.

    Science.gov (United States)

    Del Valle Rubido, Cristina; Solano Calvo, Juan Antonio; Rodríguez Miguel, Antonio; Delgado Espeja, Juan José; González Hinojosa, Jerónimo; Zapico Goñi, Álvaro

    2015-01-01

    To show the decrease in pain and better tolerance to inhalation analgesia with a 50% equimolar mixture of nitrogen protoxide and oxygen in hysteroscopic polypectomy compared with paracervical anesthesia and a control group. One hundred six patients scheduled for office hysteroscopy and polypectomy were divided into the following 3 groups: the control group, the nitrous oxide group, and the paracervical infiltration group. Patients were assigned sequentially (Canadian Task Force classification II-1). The study took place in a hysteroscopy outpatient clinic under the supervision of a gynecologist and 2 nurses trained to cooperate in the trial. One hundred six women from Area III of Madrid Community, Spain, who had been diagnosed with endometrial polyps at a gynecology office and were scheduled for office hysteroscopy and polypectomy agreed to participate in the study. Patients in group 1 (control group) received no treatment. Group 2 received inhaled nitrous oxide and group 3 paracervical infiltration with 1% lidocaine. Pain was assessed using the visual analog scale (0-10). Pain perceived by patients was lower in the nitrous Oxide group (mean: 3.55 ± 0.60, median: 3) versus the control group (mean: 5.49 ± 1.88, median: 6, p nitrous oxide group, and good for the paracervical infiltration group (p nitrous oxide group, whereas in the paracervical infiltration group, there were complications in more than 50% of the patients. No severe complications occurred. Nitrous oxide is a safe and effective analgesic technique for polipectomy office hysteroscopy compared with the paracervical infiltration and control groups. Copyright © 2015 AAGL. Published by Elsevier Inc. All rights reserved.

  12. Direct Nitrous Oxide Emission from the Aquacultured Pacific White Shrimp (Litopenaeus vannamei).

    Science.gov (United States)

    Heisterkamp, Ines M; Schramm, Andreas; de Beer, Dirk; Stief, Peter

    2016-07-01

    The Pacific white shrimp (Litopenaeus vannamei) is widely used in aquaculture, where it is reared at high stocking densities, temperatures, and nutrient concentrations. Here we report that adult L. vannamei shrimp emit the greenhouse gas nitrous oxide (N2O) at an average rate of 4.3 nmol N2O/individual × h, which is 1 to 2 orders of magnitude higher than previously measured N2O emission rates for free-living aquatic invertebrates. Dissection, incubation, and inhibitor experiments with specimens from a shrimp farm in Germany indicated that N2O is mainly produced in the animal's gut by microbial denitrification. Microsensor measurements demonstrated that the gut interior is anoxic and nearly neutral and thus is favorable for denitrification by ingested bacteria. Dinitrogen (N2) and N2O accounted for 64% and 36%, respectively, of the nitrogen gas flux from the gut, suggesting that the gut passage is too fast for complete denitrification to be fully established. Indeed, shifting the rearing water bacterial community, a diet component of shrimp, from oxic to anoxic conditions induced N2O accumulation that outlasted the gut passage time. Shrimp-associated N2O production was estimated to account for 6.5% of total N2O production in the shrimp farm studied here and to contribute to the very high N2O supersaturation measured in the rearing tanks (2,099%). Microbial N2O production directly associated with aquacultured animals should be implemented into life cycle assessments of seafood production. The most widely used shrimp species in global aquaculture, Litopenaeus vannamei, is shown to emit the potent greenhouse gas nitrous oxide (N2O) at a particularly high rate. Detailed experiments reveal that N2O is produced in the oxygen-depleted gut of the animal by bacteria that are part of the shrimp diet. Upon ingestion, these bacteria experience a shift from oxic to anoxic conditions and therefore switch their metabolism to the anaerobic denitrification process, which produces N

  13. Nitrous oxide provides safe and effective analgesia for minor paediatric procedures - a systematic review

    DEFF Research Database (Denmark)

    Pedersen, Rie S; Bayat, Allan; Steen, Nick Phaff

    2013-01-01

    Pain and distress during minor hospital-related procedures is a familiar problem in many children. Inadequate relief of children's procedural pain and distress not only affects the experience of the children and their parents, but also adversely impacts procedural success. We aimed to review the ...... the safety and efficacy of nitrous oxide during brief, but painful paediatric procedures and to compare nitrous oxide with some of the commonly used pharmacological and non-pharmacological treatments for relieving anxiety and mild to moderate pain in Denmark....

  14. Homocysteine levels after nitrous oxide anesthesia for living-related donor renal transplantation: a randomized, controlled, double-blind study.

    Science.gov (United States)

    Coskunfirat, N; Hadimioglu, N; Ertug, Z; Akbas, H; Davran, F; Ozdemir, B; Aktas Samur, A; Arici, G

    2015-03-01

    Nitrous oxide anesthesia increases postoperative homocysteine concentrations. Renal transplantation candidates present with higher homocysteine levels than patients with no renal disease. We designed this study to investigate if homocysteine levels are higher in subjects receiving nitrous oxide for renal transplantation compared with subjects undergoing nitrous oxide free anesthesia. Data from 59 patients scheduled for living-related donor renal transplantation surgery were analyzed in this randomized, controlled, blinded, parallel-group, longitudinal trial. Patients were assigned to receive general anesthesia with (flowmeter was set at 2 L/min nitrous oxide and 1 L/min oxygen) or without nitrous oxide (2 L/min air and 1 L/min oxygen). We evaluated levels of total homocysteine and known determinants, including creatinine, folate, vitamin B12, albumin, and lipids. We evaluated factor V and von Willebrand factor (vWF) to determine endothelial dysfunction and creatinine kinase myocardial band (CKMB)-mass, troponin T to show myocardial ischemia preoperatively in the holding area (T1), after discontinuation of anesthetic gases (T2), and 24 hours after induction (T3). Compared with baseline, homocysteine concentrations significantly decreased both in the nitrous oxide (22.3 ± 16.3 vs 11.8 ± 9.9; P nitrous oxide-free groups (21.5 ± 15.3 vs 8.0 ± 5.7; P nitrous oxide group had significantly higher mean plasma homocysteine concentrations than the nitrous oxide-free group (P = .021). The actual homocysteine difference between groups was 3.8 μmol/L. This study shows that homocysteine levels markedly decrease within 24 hours after living-related donor kidney transplantation. Patients receiving nitrous oxide have a lesser reduction, but this finding is unlikely to have a clinical relevance. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Maternal Expectations and Experiences of Labor Analgesia With Nitrous Oxide

    Science.gov (United States)

    Pasha, Hajar; Basirat, Zahra; Hajahmadi, Mahmood; Bakhtiari, Afsaneh; Faramarzi, Mahbobeh; Salmalian, Hajar

    2012-01-01

    Background Although there are various methods for painless delivery such as using entonox gas, most of the people are unfamiliar or concerned about it yet. Objectives The purpose of this study was to assess maternal expectations and experience of labor analgesia with nitrous oxide. Patients and Methods In a clinical trial study, 98 pregnant women in active phase of delivery were studied randomly in two groups (intervention group = 49, control group = 49) after obtaining written consent. Efficacy, experience satisfaction, and also expectation of pregnant women about entonox gas in two groups were compared, likewise in intervention group before and after using entonox gas. Results Most of the pregnant women receiving entonox gas had less labor pain (91.8%), and were satisfied with it (98%). The severity of pain in the most of entonox user was moderate level (46.94%), while for the control group it was severe (55.10%) which was significant, 40.82% of the mother in entonox group had a severe pain and 10.20% had a very severe pain, whereas in the control group (55.10%) of the mother had a severe pain and 26.53% of the had very severe pain (P = 0.004). efficacy of labor pain was in moderate level in most cases. 49% of pregnant women receiving gas described their experience as a good and excellent. 80.9% indicated that they will request the mentioned painless method in the future. The amount of suffering from gas side effects was mild in most patients of intervention group (63%). Expectations of the majority of pregnant women in intervention group (before receiving gas) and control group for painless delivery were weak (65.3%, 40.9%). The percentage of positive expectations had increased after receiving entonox gas (P = 0.01). There was a difference between the expectations of intervention group receiving entonox gas and control group (P = 0.001). Positive expectations were more in intervention group than the control group. Most differences of expectations in intervention

  16. Maternal expectations and experiences of labor analgesia with nitrous oxide.

    Science.gov (United States)

    Pasha, Hajar; Basirat, Zahra; Hajahmadi, Mahmood; Bakhtiari, Afsaneh; Faramarzi, Mahbobeh; Salmalian, Hajar

    2012-12-01

    Although there are various methods for painless delivery such as using entonox gas, most of the people are unfamiliar or concerned about it yet. The purpose of this study was to assess maternal expectations and experience of labor analgesia with nitrous oxide. In a clinical trial study, 98 pregnant women in active phase of delivery were studied randomly in two groups (intervention group = 49, control group = 49) after obtaining written consent. Efficacy, experience satisfaction, and also expectation of pregnant women about entonox gas in two groups were compared, likewise in intervention group before and after using entonox gas. Most of the pregnant women receiving entonox gas had less labor pain (91.8%), and were satisfied with it (98%). The severity of pain in the most of entonox user was moderate level (46.94%), while for the control group it was severe (55.10%) which was significant, 40.82% of the mother in entonox group had a severe pain and 10.20% had a very severe pain, whereas in the control group (55.10%) of the mother had a severe pain and 26.53% of the had very severe pain (P = 0.004). efficacy of labor pain was in moderate level in most cases. 49% of pregnant women receiving gas described their experience as a good and excellent. 80.9% indicated that they will request the mentioned painless method in the future. The amount of suffering from gas side effects was mild in most patients of intervention group (63%). Expectations of the majority of pregnant women in intervention group (before receiving gas) and control group for painless delivery were weak (65.3%, 40.9%). The percentage of positive expectations had increased after receiving entonox gas (P = 0.01). There was a difference between the expectations of intervention group receiving entonox gas and control group (P = 0.001). Positive expectations were more in intervention group than the control group. Most differences of expectations in intervention group before and after receiving the gas were

  17. Nitrous Oxide and Serious Long-term Morbidity and Mortality in the Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II Trial.

    Science.gov (United States)

    Leslie, Kate; Myles, Paul S; Kasza, Jessica; Forbes, Andrew; Peyton, Philip J; Chan, Matthew T V; Paech, Michael J; Sessler, Daniel I; Beattie, W Scott; Devereaux, P J; Wallace, Sophie

    2015-12-01

    The Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II trial randomly assigned 7,112 noncardiac surgery patients at risk of perioperative cardiovascular events to 70% N2O or 70% N2 groups. The aim of this follow-up study was to determine the effect of nitrous oxide on a composite primary outcome of death and major cardiovascular events at 1 yr after surgery. One-year follow-up was conducted via a medical record review and telephone interview. Disability was defined as a Katz index of independence in activities of daily living score less than 8. Adjusted odds ratios and hazard ratios were calculated as appropriate for primary and secondary outcomes. Among 5,844 patients evaluated at 1 yr, 435 (7.4%) had died, 206 (3.5%) had disability, 514 (8.8%) had a fatal or nonfatal myocardial infarction, and 111 (1.9%) had a fatal or nonfatal stroke during the 1-yr follow-up period. Exposure to nitrous oxide did not increase the risk of the primary outcome (odds ratio, 1.08; 95% CI, 0.94 to 1.25; P = 0.27), disability or death (odds ratio, 1.07; 95% CI, 0.90 to 1.27; P = 0.44), death (hazard ratio, 1.17; 95% CI, 0.97 to 1.43; P = 0.10), myocardial infarction (odds ratio, 0.97; 95% CI, 0.81 to 1.17; P = 0.78), or stroke (odds ratio, 1.08; 95% CI, 0.74 to 1.58; P = 0.70). These results support the long-term safety of nitrous oxide administration in noncardiac surgical patients with known or suspected cardiovascular disease.

  18. Awassi sheep keeping in the Arabic steppe in relation to nitrous oxide emission from soil

    Directory of Open Access Journals (Sweden)

    Omar Hijazi

    2014-10-01

    Full Text Available Sheep husbandry is the main source of income for farmers in arid zones. Increasing sheep production on steppes may increase the greenhouse gas production. The objective of this study was to investigate the nitrous oxide (N2O emissions from the steppes for Awassi sheep keeping and feed cropping in arid zones such as Syria. The methodology developed by the Intergovernmental Panel on Climate Change (IPCC was used to estimate N2O emissions. A survey was conducted on 64 farms in Syria to gather data for analysis. Precipitation and crop yield data from 2001 to 2009 were also used for calculation and modelling. Sheep-keeping systems, precipitation, year and the region have significant effects on N2O emissions (p < 0.05. Emissions of N2O from lands with extensive, semi-intensive and intensive systems were 0.30 ± 0.093, 0.598 ± 0.113 and 2.243 ± 0.187 kg sheep−1year−1, respectively. Crop production was higher in regions with high precipitation levels, which helped to reduce N2O emissions. Using more residuals of wheat, cotton and soya as feed for sheep in the keeping systems evaluated may decrease the overuse of steppe regions and N2O emissions. Nitrous oxide emissions of N2O from sheep-keeping areas can be reduced by changing sheep-keeping systems and increasing the crop production in arid zones through artificial irrigation.

  19. Statics and dynamics of nitrous oxide and nitrogen oxide adsorption on acid-resisting adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Kovalev, S.D.; Starobinets, S.E.; Kefer, P.G.; Puzanov, I.S.

    1982-01-01

    The basic quantitative characteristics of statics of nitrous oxide and nitrogen oxide adsorption on H - mordenite, Na - erionite, KSM silica gel and also dynamics of N/sub 2/O and NO adsorption on H - mordenite are obtained to develop the adsorption method of nitrogen oxide release from technological gaseous mixture of power plant with a dissociating coolant. The parameters ''n'' and ''E'' of the equation of the theory of volumetric filling in N/sub 2/O adsorption on H-mordenite are equal to 2.5 and 16.4 kj respectively, the height of the operating layer is 0.08-0.15 m with gaseous flow velocity 0.05-0.2 m/sec. NO adsorption is localized and isn't accompanied by disproportionation to N/sub 2/O and NO/sub 2/ with concentrations less than 20 vol.%.

  20. Fluxed of nitrous oxide and methane in a lake border ecosystem in northern Germany

    Energy Technology Data Exchange (ETDEWEB)

    Rusch, H.; Rembges, D.; Papke, H.; Rennenberg, H. [Fraunhofer Inst. for Atmospheric Environmental Research, Garmisch-Partenkirchen (Germany)

    1995-12-31

    Methane and nitrous oxide are radiatively active trace gases. This accounts for approximately 20 % of the total anticipated greenhouse effect. The atmospheric mixing ratio of both gases has increased significantly during the last decades at a rate of 0.25 % yr{sup -l} for N{sub 2}O and a rate of 1 % yr{sup -1} for CH{sub 4}. Whether this increase is caused by enhanced biogenic production of both gases or is due to decreased global sinks, has not been definitely elucidated. Soils are an important source of methane and nitrous oxide. Natural wetlands, e.g., have a similar global source strength of methane as rice paddies. On the other hand, well aerated grasslands have been shown to be a sink for atmospheric methane due to methane oxidation. Nitrous oxide is emitted by a wide range of soil types. Its rate of emission is strongly enhanced by nitrogen fertilization. In the present study, fluxes of methane and nitrous oxide were determined in a lake border ecosystem along a toposequence from reed to dry pasture. The aim of this study was to characterize the influence of soil type, land use and season on the flux rates of these greenhouse gases. (author)

  1. Oxygen concentrators performance with nitrous oxide at 50:50 volume.

    Science.gov (United States)

    Moll, Jorge Ronaldo; Vieira, Joaquim Edson; Gozzani, Judymara Lauzi; Mathias, Lígia Andrade Silva Telles

    2014-01-01

    Few investigations have addressed the safety of oxygen from concentrators for use in anesthesia in association with nitrous oxide. This study evaluated the percent of oxygen from a concentrator in association with nitrous oxide in a semi-closed rebreathing circuit. Adult patients undergoing low risk surgery were randomly allocated into two groups, receiving a fresh gas flow of oxygen from concentrators (O293) or of oxygen from concentrators and nitrous oxide (O293N2O). The fraction of inspired oxygen and the percentage of oxygen from fresh gas flow were measured every 10 min. The ratio of FiO2/oxygen concentration delivered was compared at various time intervals and between the groups. Thirty patients were studied in each group. There was no difference in oxygen from concentrators over time for both groups, but there was a significant improvement in the FiO2 (pnitrous oxide fell during the observation period although oxygen saturation was higher than 98.5% throughout the study. Concentrators can be considered a stable source of oxygen for use during short anesthetic procedures, either pure or in association with nitrous oxide at 50:50 volume. Copyright © 2013 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

  2. Final Report for DOE grant no. DE-FG02-04ER63883: Can soil genomics predict the impact of precipitation on nitrous oxide flux from soil

    Energy Technology Data Exchange (ETDEWEB)

    Egbert Schwartz

    2008-12-15

    Nitrous oxide is a potent greenhouse gas that is released by microorganisms in soil. However, the production of nitrous oxide in soil is highly variable and difficult to predict. Future climate change may have large impacts on nitrous oxide release through alteration of precipitation patterns. We analyzed DNA extracted from soil in order to uncover relationships between microbial processes, abundance of particular DNA sequences and net nitrous oxide fluxes from soil. Denitrification, a microbial process in which nitrate is used as an electron acceptor, correlated with nitrous oxide flux from soil. The abundance of ammonia oxidizing archaea correlated positively, but weakly, with nitrous oxide production in soil. The abundance of bacterial genes in soil was negatively correlated with gross nitrogen mineralization rates and nitrous oxide release from soil. We suggest that the most important control over nitrous oxide production in soil is the growth and death of microorganisms. When organisms are growing nitrogen is incorporated into their biomass and nitrous oxide flux is low. In contrast, when microorganisms die, due to predation or infection by viruses, inorganic nitrogen is released into the soil resulting in nitrous oxide release. Higher rates of precipitation increase access to microorganisms by predators or viruses through filling large soil pores with water and therefore can lead to large releases of nitrous oxide from soil. We developed a new technique, stable isotope probing with 18O-water, to study growth and mortality of microorganisms in soil.

  3. Methane and Nitrous Oxide Emissions from Livestock Agriculture in 16 Local Administrative Districts of Korea

    Directory of Open Access Journals (Sweden)

    Eun Sook Ji

    2012-12-01

    Full Text Available This study was conducted to evaluate methane (CH4 and nitrous oxide (N2O emissions from livestock agriculture in 16 local administrative districts of Korea from 1990 to 2030. National Inventory Report used 3 yr averaged livestock population but this study used 1 yr livestock population to find yearly emission fluctuations. Extrapolation of the livestock population from 1990 to 2009 was used to forecast future livestock population from 2010 to 2030. Past (yr 1990 to 2009 and forecasted (yr 2010 to 2030 averaged enteric CH4 emissions and CH4 and N2O emissions from manure treatment were estimated. In the section of enteric fermentation, forecasted average CH4 emissions from 16 local administrative districts were estimated to increase by 4%–114% compared to that of the past except for Daejeon (−63%, Seoul (−36% and Gyeonggi (−7%. As for manure treatment, forecasted average CH4 emissions from the 16 local administrative districts were estimated to increase by 3%–124% compared to past average except for Daejeon (−77%, Busan (−60%, Gwangju (−48% and Seoul (−8%. For manure treatment, forecasted average N2O emissions from the 16 local administrative districts were estimated to increase by 10%–153% compared to past average CH4 emissions except for Daejeon (−60%, Seoul (−4.0%, and Gwangju (−0.2%. With the carbon dioxide equivalent emissions (CO2-Eq, forecasted average CO2-Eq from the 16 local administrative districts were estimated to increase by 31%–120% compared to past average CH4 emissions except Daejeon (−65%, Seoul (−24%, Busan (−18%, Gwangju (−8% and Gyeonggi (−1%. The decreased CO2-Eq from 5 local administrative districts was only 34 kt, which was insignificantly small compared to increase of 2,809 kt from other 11 local administrative districts. Annual growth rates of enteric CH4 emissions, CH4 and N2O emissions from manure management in Korea from 1990 to 2009 were 1.7%, 2.6%, and 3.2%, respectively. The

  4. Field Trial of Methoxyflurane, Nitrous Oxide, and Trichloroethylene as Obstetric Analgesics

    Science.gov (United States)

    Rosen, M.; Mushin, W. W.; Jones, P. L.; Jones, E. V.

    1969-01-01

    In a field trial of 1,257 patients receiving methoxyflurane, trichloroethylene, and nitrous-oxide/oxygen for the relief of pain in labour methoxyflurane has been shown to have certain advantages which support its use in midwifery practice. The trial confirms our objective method for screening an inhalational agent as an obstetric analgesic. PMID:4895340

  5. Nitrous oxide does not influence operating conditions or postoperative course in colonic surgery

    DEFF Research Database (Denmark)

    Krogh, B; Jørn Jensen, P; Henneberg, S W

    1994-01-01

    groups. Anaesthesia included propofol by infusion, pancuronium and fentanyl 3 micrograms kg-1 h-1. The air-oxygen group required a continuous infusion of propofol of 4-6 mg kg-1 h-1 whereas the nitrous oxide-oxygen group required only 1-2 mg kg-1 h-1. There were no differences between the groups...

  6. Nitrous oxide fluxes and nitrogen cycling along a pasturechronosequence in Central Amazonia, Brazil

    Science.gov (United States)

    B. Wick; E. Veldkamp; W. Z. de Mello; M. Keller; P. Crill

    2005-01-01

    We studied nitrous oxide (N2O) fluxes and soil nitrogen (N) cycling following forest conversion to pasture in the central Amazon near Santarém, Pará, Brazil. Two undisturbed forest sites and 27 pasture sites of 0.5 to 60 years were sampled once each during wet and dry seasons. In addition to soil-atmosphere fluxes of N...

  7. Effect of copper dosing on sulfide inhibited reduction of nitric and nitrous oxide

    NARCIS (Netherlands)

    Manconi, I.; Maas, van der P.M.F.; Lens, P.N.L.

    2006-01-01

    The stimulating effect of copper addition on the reduction rate of nitrous oxide (N2O) to dinitrogen (N2) in the presence of sulfide was investigated in batch experiments (pH 7.0; 55 °C). N2O was dosed either directly as a gas to the headspace of the bottles or formed as intermediate during the

  8. land-use and land-use change effects on nitrous oxide emissions

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    Nitrous oxide (N2O) is a greenhouse gas (GHG) with a considerable warming potential and involvement in the destruction of stratospheric ozone. The conversion of savannas to agricultural land has the potential of changing the characteristics and gas exchange of the ecosystems dramatically. The savanna woodlands ...

  9. Effects of climate and management intensity on nitrous oxide emissions in grassland systems across Europe

    NARCIS (Netherlands)

    Flechard, C.; Ambus, P.; Skiba, U.; Rees, R.M.; Hensen, A.; Amstel, van A.R.; Pol, van den A.; Soussana, J.F.; Jones, M.; Clifton-Brown, J.C.; Rachi, A.; Horvath, L.; Neftel, A.; Jocher, M.; Ammann, C.R.; Leifeld, J.; Fuhrer, J.; Calanca, P.; Thalman, E.; Pilegaard, K.; Marco, Di G.S.; Campbell, C.; Nemitz, E.; Hargreaves, K.J.; Levy, P.E.; Ball, B.; Jones, S.K.; Bulk, van de W.C.M.; Groot, T.; Blom, M.; Domingues, R.; Kasper, G.J.; Allard, V.; Ceschia, E.; Cellier, P.; Laville, P.; Henault, C.; Bizouard, F.; Abdalla, M.; Williams, M.; Baronti, S.; Berretti, F.; Grosz, B.

    2007-01-01

    Soil/atmosphere exchange fluxes of nitrous oxide were monitored for a 3-year period at 10 grassland sites in eight European countries (Denmark, France, Hungary, Ireland, Italy, The Netherlands, Switzerland and United Kingdom), spanning a wide range of climatic, environmental and soil conditions.

  10. Spatial variability in nitrous oxide and methane emissions from beef cattle feedyard pen surfaces

    Science.gov (United States)

    Greenhouse gas emissions from beef cattle feedlots include enteric carbon dioxide and methane, and manure-derived methane, nitrous oxide and carbon dioxide. Enteric methane comprises the largest portion of the greenhouse gas footprint of beef cattle feedyards. For the manure component, methane is th...

  11. Nitrous oxide emission hotspots and acidic soil denitrification in a riparian buffer zone

    NARCIS (Netherlands)

    van den Heuvel, R.N.|info:eu-repo/dai/nl/298202883

    2010-01-01

    Nitrous oxide (N2O) is a greenhouse gas with a global warming potential of 296 CO2 equivalents and is involved in the depletion of the ozone layer. Through studies on emission sources it was revealed that natural and agricultural soils are important sources of N2O emissions and are responsible for

  12. The effect of sepsis and short-term exposure to nitrous oxide on the ...

    African Journals Online (AJOL)

    It is recognised that prolonged anaesthesia with nitrous oxide (N20) induces megaloblastic anaemia by oxidising vitamin B12 To determine whether sepsis aggravates the effect of H20 on haemopoiesis 5 patients with severe sepsis, who required surgery and were exposed to short-term (45 - 105 minutes) N20 anaesthesia, ...

  13. Nitrous Oxide (N2O) emissions from human waste in 1970-2050

    NARCIS (Netherlands)

    Strokal, M.; Kroeze, C.

    2014-01-01

    Nitrous oxide (N2O) is an important contributor to climate change. Human waste is an important source of N2O emissions in several world regions, and its share in global emissions may increase in the future. In this paper we, therefore, address N2O emission from human waste: collected (from treatment

  14. Biochar's role in mitigating soil nitrous oxide emissions: a review and meta-analysis

    NARCIS (Netherlands)

    Cayuela, M.L.; Zwieten, van L.; Singh, B.P.; Jeffery, S.L.; Roig, A.; Sánchez-Monedero, M.A.

    2014-01-01

    More than two thirds of global nitrous oxide (N2O) emissions originate from soil, mainly associated with the extensive use of nitrogen (N) fertilizers in agriculture. Although the interaction of black carbon with the N cycle has been long recognized, the impact of biochar on N2O emissions has only

  15. Future trends in worldwide river nitrogen transport and related nitrous oxide emissions : a scenario analysis

    NARCIS (Netherlands)

    Kroeze, C.; Seitzinger, S.P.; Domingues, R.

    2001-01-01

    We analyze possible future trends in dissolved inorganic nitrogen (DIN) export by world rivers and associated emissions of nitrous oxide (N2O). Our scenarios either assume that current trends continue or that nitrogen (N) inputs to aquatic systems are reduced as a result of changes in agriculture

  16. Comparing Nitrous Oxide Emissions from Three Residential Landscapes under Different Management Schemes Following Natural Rainfall Events

    Science.gov (United States)

    Cultural lawn management practices that produce aesthetically appealing landscapes may also create environmental conditions that stimulate soil nitrous oxide (N2O) emissions. The purpose of this study is to investigate the effects of lawn management practices on N2O fluxes from ...

  17. Relationship between gross nitrogen cycling and nitrous oxide emission in grass-cliver pasture

    DEFF Research Database (Denmark)

    Ambus, P.

    2005-01-01

    of various ages (production year 1, 2 and 8). The experimental approach included cross-labelling pasture monoliths with (15)N-enriched substrates to identify sources of N(2)O, in combination with assessment of gross N mineralization and nitrification. Nitrous oxide emissions were generally low, fluctuating...

  18. Effectiveness of nitrous oxide for postpartum perineal repair: a randomised controlled trial.

    Science.gov (United States)

    Berlit, Sebastian; Tuschy, Benjamin; Brade, Joachim; Mayer, Jade; Kehl, Sven; Sütterlin, Marc

    2013-10-01

    To compare the effectiveness of self-administered 50% nitrous oxide and conventional infiltrative anaesthesia with 1% prilocaine hydrochloride in postpartum perineal repair. A total of 100 women were prospectively enrolled and randomised to receive either infiltrative anaesthesia or a self-administered nitrous oxide mixture (Livopan(©)) for pain relief during postpartum perineal suturing. Besides data concerning anaesthesia, characteristics of patients and labour were documented for statistical analysis. Pain experienced during perineal repair was assessed using the short form of the McGill Pain Questionnaire (SF-MPQ). Forty-eight women received nitrous oxide and 52 underwent perineal suturing after infiltrative anaesthesia. There were no statistically significant differences regarding maternal age, body mass index (BMI), duration of pregnancy and suturing time between the groups. The most frequent birth injury was second-degree perineal laceration in the study group [22/48; 46%] and episiotomy in the control group [18/52; 35%]. Pain experienced during genital tract suturing and patients' satisfaction showed no statistically significant differences between the groups. Thirty-seven women in the study group and 47 in the control group were satisfied with the anaesthesia during perineal repair and would recommend it to other parturients [37/48, 77% vs. 47/52, 90%; p=0.0699). Nitrous oxide self-administration during genital tract suturing after vaginal childbirth is a satisfactory and effective alternative to infiltrative anaesthesia. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  19. Nitrate leaching and nitrous oxide flux in urban forests and grasslands

    Science.gov (United States)

    Peter M. Groffman; Candiss O. Williams; Richard V. Pouyat; Lawrence E. Band; Ian D. Yesilonis

    2009-01-01

    Urban landscapes contain a mix of land-use types with different patterns of nitrogen (N) cycling and export. We measured nitrate (NO3-) leaching and soil:atmosphere nitrous oxide (N2O) flux in four urban grassland and eight forested long-term study plots in the Baltimore, Maryland metropolitan area....

  20. Predicting nitrous oxide emissions from manure properties and soil moisture: An incubation experiment

    DEFF Research Database (Denmark)

    Baral, Khagendra Raj; Arthur, Emmanuel; Olesen, Jørgen Eivind

    2016-01-01

    Field-applied manure is a source of essential plant nutrients, but benefits may be partly offset by high rates of nitrous oxide (N2O) emissions, as modified by manure characteristics and soil properties. In a 28-d incubation experiment we quantified short-term emissions of N2O from a sandy loam...

  1. Differential effects of nitrous oxide and propofol on myogenic transcranial motor evoked responses during sufentanil anaesthesia

    NARCIS (Netherlands)

    Ubags, L. H.; Kalkman, C. J.; Been, H. D.; Drummond, J. C.

    1997-01-01

    We have compared the effects of 50% nitrous oxide and propofol, each administered concurrently with sufentanil, on the amplitudes and latencies of the compound muscle action potential (CMAP) response to transcranial electrical stimulation. Using a crossover design, 12 patients undergoing spinal

  2. Land-use and land-use change effects on nitrous oxide emissions in ...

    African Journals Online (AJOL)

    Nitrous oxide (N2O) is a greenhouse gas (GHG) with a considerable warming potential and involvement in the destruction of stratospheric ozone. The conversion of savannas to agricultural land has the potential of changing the characteristics and gas exchange of the ecosystems dramatically. The savanna woodlands ...

  3. The Effect of Various Concentrations of Nitrous Oxide and Oxygen on the Hypersensitive Gag Reflex.

    Science.gov (United States)

    De Veaux, Candace K E; Montagnese, Thomas A; Heima, Masahiro; Aminoshariae, Anita; Mickel, Andre

    2016-01-01

    The purpose of this study was to compare the effectiveness of various concentrations of N2O/O2 on obtunding a hypersensitive gag reflex. We hypothesized that the administration of nitrous oxide and oxygen would obtund a hypersensitive gag reflex enough to allow a patient to tolerate the placement and holding of a digital x-ray sensor long enough to obtain a dental radiograph. Volunteers claiming to have a hypersensitive gag reflex were first screened to validate their claim and then tested by placing a size 2 digital x-ray sensor in the position for a periapical radiograph of the right mandibular molar area and holding it in place for 10 seconds. Subjects were first tested using room air only, then 30%, 50%, or 70% nitrous oxide until they were able to tolerate the sensor without gagging or discomfort. A visual analog scale was used for subjective responses, and other statistical tests were used to analyze the results. We found that for some subjects, 30% nitrous oxide was sufficient; for others, 50% was needed; and for the remainder of the subjects, 70% was sufficient to tolerate the test. Using a combination of 70% nitrous oxide and 30% oxygen allowed all patients claiming to have a hypersensitive gag reflex to tolerate the placement and holding of a digital x-ray sensor long enough to take a periapical radiograph.

  4. Nitrous oxide production in sputum from cystic fibrosis patients with chronic Pseudomonas aeruginosa lung infection

    DEFF Research Database (Denmark)

    Kolpen, Mette; Kühl, Michael; Bjarnsholt, Thomas

    2014-01-01

    local anoxia by consuming the majority of O2 for production of reactive oxygen species (ROS). We hypothesized that P. aeruginosa acquires energy for growth in anaerobic endobronchial mucus by denitrification, which can be demonstrated by production of nitrous oxide (N2O), an intermediate...

  5. Anti-leukemic potential of methyl-cobalamin inactivation by nitrous oxide

    NARCIS (Netherlands)

    J. Abels; A.C.M. Kroes (Aloys C.M.); A.A.M. Ermens (Anton); J. van Kapel (Jan); M. Schoester (Martijn); L.J.M. Spijkers (L. J M); J. Lindemans (Jan)

    1990-01-01

    textabstractMyelo‐cytotoxicity of extended nitrous oxide (N2O) inhalation was described almost forty years ago and then incidentally applied already with temporary success for suppressing leukemia. In 1948 the accompanying megaloblastic maturation arrest was explained by inactivation of the

  6. Nitrous oxide emissions from multiple combined applications of fertiliser and cattle slurry to grassland

    NARCIS (Netherlands)

    Schils, R.L.M.; Groenigen, van J.W.; Velthof, G.L.; Kuikman, P.J.

    2008-01-01

    Fertiliser and manure application are important sources of nitrous oxide (N2O) emissions from agricultural soils. The current default IPCC emission factor of 1.0% is independent of the type of fertiliser and manure, and application time, method and rate. However, in the IPCC Tiered system it is

  7. Interaction between Nitrous Oxide, Sevoflurane, and Opioids A Response Surface Approach

    NARCIS (Netherlands)

    Vereecke, Hugo E. M.; Proost, Johannes H.; Heyse, Bjorn; Eleveld, Douglas J.; Katoh, Takasumi; Luginbuehl, Martin; Struys, Michel M. R. F.

    Background: The interaction of sevoflurane and opioids can be described by response surface modeling using the hierarchical model. We expanded this for combined administration of sevoflurane, opioids, and 66 vol.% nitrous oxide (N2O), using historical data on the motor and hemodynamic responsiveness

  8. Spatial oxygen distribution and nitrous oxide emissions from soil after manure application

    DEFF Research Database (Denmark)

    Zhu, Kun; Bruun, Sander; Larsen, Morten

    2014-01-01

    The availability and spatial distribution of oxygen (O2) in agricultural soil are controlling factors in the production and emission of nitrous oxide (N2O) to the atmosphere, but most experiments investigating the effects of various factors on N2O emissions in soil have been conducted without det...

  9. Ethical considerations in the use of nitrous oxide in pediatric dentistry.

    Science.gov (United States)

    Levering, Nicholas J; Welie, Jos V M

    2010-01-01

    Nitrous oxide (N2O) has become a routine intervention in contemporary American dental practice, especially in the management of children. However, routines translate to confidence which in turn may lead to overconfidence, such that possible risks and misuses are insufficiently acknowledged. This article ethically evaluates the use of nitrous oxide as a practice routine in treating children. Nitrous oxide administration is analyzed in reference to three internationally acknowledged principles of dental ethics: nonmaleficence, beneficence, and patient autonomy. In reference to the principle of nonmaleficence, the potential for adverse effects of N2O is discussed, particularly when it is administered in conjunction with other sedatives and anesthetics. The importance of abiding by clinical protocols is emphasized. Next, in reference to the principle of beneficence, the authors address the problematic application of N2O for the benefit of individuals other than the patient (e.g., dentists and parents). Finally, the importance of respecting patient autonomy is discussed, specifically the need to obtain explicit consent for N2O. The article supports the continued use of nitrous oxide but advises greater attention to how and why it is administered. Four recommendations are offered for an ethically sound usage.

  10. Nitrous oxide does not influence operating conditions or postoperative course in colonic surgery

    DEFF Research Database (Denmark)

    Krogh, B; Jørn Jensen, P; Henneberg, S W

    1994-01-01

    We studied 150 patients undergoing elective colonic surgery; they were allocated randomly to undergo artificial ventilation with either air-oxygen or nitrous oxide-oxygen during surgery. Eleven patients were excluded. Preoperative management, surgery and postoperative analgesia were similar in bo...

  11. Effects of measures on nitrous oxide emissions from agriculture : using INITIATOR and IPCC methods

    NARCIS (Netherlands)

    Vries, de W.; Kros, J.

    2011-01-01

    The mandatory national reporting of nitrous oxide (N2O) emissions under the UN Climate Change Convention is usually done with the IPCC inventory approach using default emission factors for N2O emissions from different sources. Although simple and transparent, the drawback is that emissions will

  12. Emissions of methane and nitrous oxide from full-scale municipal wastewater treatment plants

    NARCIS (Netherlands)

    Daelman, M.R.J.

    2014-01-01

    Since 1750, the year that commonly marks the start of the Industrial Revolution, the atmospheric concentrations of carbon dioxide, methane and nitrous oxide have risen about 40 %, 150 % and 20 %, respectively, above the pre-industrial levels due to human activity (IPCC (2013) Climate Change 2013:

  13. Nitrous Oxide and Methane Fluxes from Smallholder Farms: A Scoping Study in the Anjeni Watershed

    Directory of Open Access Journals (Sweden)

    Haimanote K. Bayabil

    2016-12-01

    Full Text Available While agricultural practices are widely reported to contribute to anthropogenic greenhouse gas (GHG emissions, there are only limited measurements available for emission rates in the monsoon climate of the African continent. We conducted a scoping study to measure nitrous oxide (N2O-N and methane (CH4 emission rates from 24 plots constructed on smallholder agricultural farms along the slope catena of three transects in the sub-humid Anjeni watershed in the Ethiopian highlands. Greenhouse gas flux samples were collected in 2013, before, towards the end, and after the rainy monsoon phase. At each location, three plots were installed in groups: two plots grown with barley (one enriched with charcoal and the other without soil amendment and lupine was grown on the third plot without any soil amendment. Preliminary study results showed that nitrous oxide emission rates varied from −275 to 522 μg·m−2·h−1 and methane emissions ranged from −206 to 264 μg·m−2·h−1 with overall means of 51 and 5 μg·m−2·h−1 for N2O-N and CH4, respectively. Compared with the control, charcoal and lupine plots had elevated nitrous oxide emissions. Plots amended with charcoal showed on average greater methane uptake than was emitted. While this study provides insights regarding nitrous oxide and methane emission levels from smallholder farms, studies of longer durations are needed to verify the results.

  14. Nitrous Oxide and Methane Fluxes from Smallholder Farms: A Scoping Study in the Anjeni Watershed.

    NARCIS (Netherlands)

    Bayabil, Haimanote K.; Stoof, C.R.; Mason, C.; Richards, B.K.; Steenhuis, T.S.

    2016-01-01

    While agricultural practices are widely reported to contribute to anthropogenic greenhouse gas (GHG) emissions, there are only limited measurements available for emission rates in the monsoon climate of the African continent. We conducted a scoping study to measure nitrous oxide (N2O-N) and methane

  15. Control strategies for nitrous oxide emissions reduction on wastewater treatment plants operation.

    Science.gov (United States)

    Santín, I; Barbu, M; Pedret, C; Vilanova, R

    2017-11-15

    The present paper focused on reducing greenhouse gases emissions in wastewater treatment plants operation by application of suitable control strategies. Specifically, the objective is to reduce nitrous oxide emissions during the nitrification process. Incomplete nitrification in the aerobic tanks can lead to an accumulation of nitrite that triggers the nitrous oxide emissions. In order to avoid the peaks of nitrous oxide emissions, this paper proposes a cascade control configuration by manipulating the dissolved oxygen set-points in the aerobic tanks. This control strategy is combined with ammonia cascade control already applied in the literature. This is performed with the objective to take also into account effluent pollutants and operational costs. In addition, other greenhouse gases emissions sources are also evaluated. Results have been obtained by simulation, using a modified version of Benchmark Simulation Model no. 2, which takes into account greenhouse gases emissions. This is called Benchmark Simulation Model no. 2 Gas. The results show that the proposed control strategies are able to reduce by 29.86% of nitrous oxide emissions compared to the default control strategy, while maintaining a satisfactory trade-off between water quality and costs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Sevoflurane-induced isoelectric EEG and burst suppression: differential and antagonistic effect of added nitrous oxide.

    Science.gov (United States)

    Niu, B; Xiao, J Y; Fang, Y; Zhou, B Y; Li, J; Cao, F; Tian, Y K; Mei, W

    2017-05-01

    The objective of this study was to investigate whether nitrous oxide influenced the ED50 of sevoflurane for induction of isoelectric electroencephalogram (ED50isoelectric ) differently from its influence on the ED50 of sevoflurane for electroencephalogram burst suppression (ED50burst ). In a prospective, randomised, double-blind, parallel group, up-down sequential allocation study, 77 ASA physical status 1 and 2 patients received sevoflurane induction and, after tracheal intubation, were randomly allocated to receive sevoflurane with either 40% oxygen in air (control group) or 60% nitrous oxide in oxygen mixture (nitrous group). The ED50isoelectric in the two groups was determined using Dixon's up and down method, starting at 2.5% with 0.2% step size of end-tidal sevoflurane. The electroencephalogram was considered as isoelectric when a burst suppression ratio of 100% lasted > 1 min. The subsequent concentrations of sevoflurane administered were determined by the presence or absence of isoelectric electroencephalogram in the previous patient in the same group. The ED50isoelectric in the nitrous group 4.08 (95%CI, 3.95-4.38)% was significantly higher than that in the control group 3.68 (95%CI, 3.50-3.78)% (p nitrous group and control group, respectively (p = 0.52). The addition of 60% nitrous oxide increases ED50isoelectric , but not the ED50burst of sevoflurane. Neither result indicates an additive effect of anaesthetic agents, as might be expected, and possible reasons for this are discussed. © 2017 The Authors. Anaesthesia published by John Wiley & Sons Ltd on behalf of Association of Anaesthetists of Great Britain and Ireland.

  17. Recent advances in mathematical modeling of nitrous oxides emissions from wastewater treatment processes.

    Science.gov (United States)

    Ni, Bing-Jie; Yuan, Zhiguo

    2015-12-15

    Nitrous oxide (N2O) can be emitted from wastewater treatment contributing to its greenhouse gas footprint significantly. Mathematical modeling of N2O emissions is of great importance toward the understanding and reduction of the environmental impact of wastewater treatment systems. This article reviews the current status of the modeling of N2O emissions from wastewater treatment. The existing mathematical models describing all the known microbial pathways for N2O production are reviewed and discussed. These included N2O production by ammonia-oxidizing bacteria (AOB) through the hydroxylamine oxidation pathway and the AOB denitrification pathway, N2O production by heterotrophic denitrifiers through the denitrification pathway, and the integration of these pathways in single N2O models. The calibration and validation of these models using lab-scale and full-scale experimental data is also reviewed. We conclude that the mathematical modeling of N2O production, while is still being enhanced supported by new knowledge development, has reached a maturity that facilitates the estimation of site-specific N2O emissions and the development of mitigation strategies for a wastewater treatment plant taking into the specific design and operational conditions of the plant. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Nitrous oxide emission by the non-denitrifying, nitrate ammonifier Bacillus licheniformis.

    Science.gov (United States)

    Sun, Yihua; De Vos, Paul; Heylen, Kim

    2016-01-19

    Firmicutes have the capacity to remove excess nitrate from the environment via either denitrification, dissimilatory nitrate reduction to ammonium or both. The recent renewed interest in their nitrogen metabolism has revealed many interesting features, the most striking being their wide variety of dissimilatory nitrate reduction pathways. In the present study, nitrous oxide production from Bacillus licheniformis, a ubiquitous Gram-positive, spore-forming species with many industrial applications, is investigated. B. licheniformis has long been considered a denitrifier but physiological experiments on three different strains demonstrated that nitrous oxide is not produced from nitrate in stoichiometric amounts, rather ammonium is the most important end-product, produced during fermentation. Significant strain dependency in end-product ratios, attributed to nitrite and ammonium, and medium dependency in nitrous oxide production were also observed. Genome analyses confirmed the lack of a nitrite reductase to nitric oxide, the key enzyme of denitrification. Based on the gene inventory and building on knowledge from other non-denitrifying nitrous oxide emitters, hypothetical pathways for nitrous oxide production, involving NarG, NirB, qNor and Hmp, are proposed. In addition, all publically available genomes of B. licheniformis demonstrated similar gene inventories, with specific duplications of the nar operon, narK and hmp genes as well as NarG phylogeny supporting the evolutionary separation of previously described distinct BALI1 and BALI2 lineages. Using physiological and genomic data we have demonstrated that the common soil bacterium B. licheniformis does not denitrify but is capable of fermentative dissimilatory nitrate/nitrite reduction to ammonium (DNRA) with concomitant production of N2O. Considering its ubiquitous nature and non-fastidious growth in the lab, B. licheniformis is a suitable candidate for further exploration of the actual mechanism of N2O

  19. The catalytic cycle of nitrous oxide reductase - The enzyme that catalyzes the last step of denitrification.

    Science.gov (United States)

    Carreira, Cíntia; Pauleta, Sofia R; Moura, Isabel

    2017-12-01

    The reduction of the potent greenhouse gas nitrous oxide requires a catalyst to overcome the large activation energy barrier of this reaction. Its biological decomposition to the inert dinitrogen can be accomplished by denitrifiers through nitrous oxide reductase, the enzyme that catalyzes the last step of the denitrification, a pathway of the biogeochemical nitrogen cycle. Nitrous oxide reductase is a multicopper enzyme containing a mixed valence CuA center that can accept electrons from small electron shuttle proteins, triggering electron flow to the catalytic sulfide-bridged tetranuclear copper "CuZ center". This enzyme has been isolated with its catalytic center in two forms, CuZ*(4Cu1S) and CuZ(4Cu2S), proven to be spectroscopic and structurally different. In the last decades, it has been a challenge to characterize the properties of this complex enzyme, due to the different oxidation states observed for each of its centers and the heterogeneity of its preparations. The substrate binding site in those two "CuZ center" forms and which is the active form of the enzyme is still a matter of debate. However, in the last years the application of different spectroscopies, together with theoretical calculations have been useful in answering these questions and in identifying intermediate species of the catalytic cycle. An overview of the spectroscopic, kinetics and structural properties of the two forms of the catalytic "CuZ center" is given here, together with the current knowledge on nitrous oxide reduction mechanism by nitrous oxide reductase and its intermediate species. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Nitrogen removal and intentional nitrous oxide production from reject water in a coupled nitritation/nitrous denitritation system under real feed-stream conditions.

    Science.gov (United States)

    Weißbach, Max; Thiel, Paul; Drewes, Jörg E; Koch, Konrad

    2018-01-31

    A Coupled Aerobic-anoxic Nitrous Decomposition Operation (CANDO) was performed over five months to investigate the performance and dynamics of nitrogen elimination and nitrous oxide production from digester reject water under real feed-stream conditions. A 93% conversion of ammonium to nitrite could be maintained for adapted seed sludge in the first stage (nitritation). The second stage (nitrous denitritation), inoculated with conventional activated sludge, achieved a conversion of 70% of nitrite to nitrous oxide after only 12 cycles of operation. The development of an alternative feeding strategy and the addition of a coagulant (FeCl3) facilitated stable operation and process intensification. Under steady-state conditions, nitrite was reliably eliminated and different nitrous oxide harvesting strategies were assessed. Applying continuous removal increased N2O yields by 16% compared to the application of a dedicated stripping phase. These results demonstrate the feasible application of the CANDO process for nitrogen removal and energy recovery from ammonia rich wastewater. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Inhaled methoxyflurane (Penthrox) sedation for third molar extraction: a comparison to nitrous oxide sedation.

    Science.gov (United States)

    Abdullah, W A; Sheta, S A; Nooh, N S

    2011-09-01

    The aim of this study was to evaluate the use of inhaled methoxyflurane (Penthrox) in the reduction of dental anxiety in patients undergoing mandibular third molar removal in a specialist surgical suite and compare it to the conventional nitrous oxide sedation. A prospective randomized, non-blinded crossover design study of 20 patients receiving two types of sedation for their third molar extraction who participated in 40 treatment sessions. At first appointment, a patient was randomly assigned to receive either nitrous oxide sedation or intermittent Penthrox inhaler sedation, with the alternate regimen administered during the second appointment. Peri-procedural vital signs (heart rate and blood pressure) were recorded and any deviations from 20% from the baseline values, as well as any drop in oxygen saturation below 92% were documented. The Ramsay Sedation Scale (RSS) score was recorded every five minutes. Patient cooperation during the procedure, patients' general opinion about the sedation technique, surgeon satisfaction and the occurrence of side effects were all recorded. After the second procedure, the patient was also asked if he or she had any preference of one sedation technique over the other. Levels of sedation were comparable in nitrous oxide and Penthrox sedation sessions. However, at 15 minutes of sedation it was significantly lighter (p methoxyflurane thought its odour was pleasant. Patients preferred methoxyflurane (Penthrox) inhalation over nitrous oxide sedation (Fisher's Exact test, p < 0.05). Adverse events were minimal. No patient was either deeply sedated or agitated. Blood pressure was within ± 20% from the baseline values. No patient had oxygen saturation less than 92%. Dizziness was the most frequently encountered side effect in both regimens (four patients each). Two patients had bradycardia (HR < 60 beats/minute) when nitrous oxide was used in comparison to one patient with Penthrox sedation. Paraesthesia of fingers and heaviness of the

  2. Crystallographic studies with xenon and nitrous oxide provide evidence for protein-dependent processes in the mechanisms of general anesthesia.

    Science.gov (United States)

    Abraini, Jacques H; Marassio, Guillaume; David, Helene N; Vallone, Beatrice; Prangé, Thierry; Colloc'h, Nathalie

    2014-11-01

    The mechanisms by which general anesthetics, including xenon and nitrous oxide, act are only beginning to be discovered. However, structural approaches revealed weak but specific protein-gas interactions. To improve knowledge, we performed x-ray crystallography studies under xenon and nitrous oxide pressure in a series of 10 binding sites within four proteins. Whatever the pressure, we show (1) hydrophobicity of the gas binding sites has a screening effect on xenon and nitrous oxide binding, with a threshold value of 83% beyond which and below which xenon and nitrous oxide, respectively, binds to their sites preferentially compared to each other; (2) xenon and nitrous oxide occupancies are significantly correlated respectively to the product and the ratio of hydrophobicity by volume, indicating that hydrophobicity and volume are binding parameters that complement and oppose each other's effects; and (3) the ratio of occupancy of xenon to nitrous oxide is significantly correlated to hydrophobicity of their binding sites. These data demonstrate that xenon and nitrous oxide obey different binding mechanisms, a finding that argues against all unitary hypotheses of narcosis and anesthesia, and indicate that the Meyer-Overton rule of a high correlation between anesthetic potency and solubility in lipids of general anesthetics is often overinterpreted. This study provides evidence that the mechanisms of gas binding to proteins and therefore of general anesthesia should be considered as the result of a fully reversible interaction between a drug ligand and a receptor as this occurs in classical pharmacology.

  3. Health hazard evaluation report HETA 86-157-1678, Stag Dental Clinic, Boulder, Colorado. [Nitrous oxide exposure

    Energy Technology Data Exchange (ETDEWEB)

    Gunter, B.J.

    1986-03-01

    Employees of the Stag Dental Clinic, Boulder, Colorado requested an evaluation of nitrous oxide exposure during dental procedures. Direct reading measurements taken in the dental operatory immediately after nitrous oxide was administered showed levels exceeding 1000 parts per million (ppm) in the breathing zone of the dentist and his assistant. The levels remained high throughout the 1-hour procedure. The level of nitrous oxide in the hallway outside the operatory was 300 ppm and that in the adjacent operatory, 150 ppm (background). General-room air in the operatory in use was 800 ppm nitrous oxide. Levels of nitrous oxide decreased to 50 ppm 1.5 hours after the gas was turned off. The current NIOSH recommended time weighted average is 25 ppm. The author concludes that a health hazard existed at the dental office due to high exposures of nitrous oxide. It was recommended that a scavenging system should be installed. Recommendations also include routine maintenance on anesthetic and suction equipment, a follow-up evaluation after the exhaust systems have been in place, advising all dentists and other personnel in the clinic of the adverse health effects due to nitrous oxide, and use of more dilution ventilation.

  4. Short exposure to acetylene to distinguish between nitrifier and denitrifier nitrous oxide production in soil and sediment samples

    NARCIS (Netherlands)

    Kester, R.A.; De Boer, W.; Laanbroek, H.J.

    1996-01-01

    The contribution of nitrifiers and denitrifiers to the nitrous oxide production in slurries of calcareous silt loam and river bank sediment at different oxygen concentrations was determined using acetylene as nitrification inhibitor. The addition of 10 Pa acetylene resulted in inhibition of nitrous

  5. Medical workers' cognition of using 50% nitrous oxide in children with burns: a qualitative study.

    Science.gov (United States)

    Wang, Hai-Xia; Li, Yu-Xiang; Zhou, Ru-Zhen; Zhao, Ji-Jun

    2015-09-01

    Pain caused by dressing among children with burns is an issue worth discussing. Medical workers' understanding of pain during dressing in children with burns is correlated with the quality of pain management. Effective pain management is significant to improve anxiety and reduce pain and psychological distress during dressing for children with burns. We aimed to investigate medical workers' understanding of current pain management during dressing among children with burns and their attitudes toward the application of 50% nitrous oxide in pain management. Interviews were conducted with seven doctors and nurses from a burn center in East China. Data were collected by in-depth interviews and qualitative description after full transcription of each interview. Three themes were identified: (1) Medical workers felt sympathy for children with burns and believed that a gap existed between the current and expected situation in pain management. In addition, the prescription of analgesics during dressing for children with burns was not favored. (2) Given the fact that 50% nitrous oxide is effective in pain management for adult patients with burns, medical workers tended to apply it to children with burns during dressing after being provided the literature on the use of 50% nitrous oxide in children. (3) Guidelines for the application of 50% nitrous oxide during dressing for children with burns require further modification. Medical workers deemed the pain management for children with burns unsatisfactory, and they supported the application of 50% nitrous oxide during dressing for children with burns. Meanwhile, they hoped that administrators would also support it. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

  6. A Nurse-Directed Model for Nitrous Oxide Use During Labor.

    Science.gov (United States)

    Pinyan, Toni; Curlee, Kelly; Keever, Mellanie; Baldwin, Kathleen M

    Nitrous oxide has a long history of use and has been well documented in the literature as a safe, effective, and inexpensive option for pain management in labor in other countries, but it is underused in the United States. Pain relief options for laboring women in rural community hospitals with a small perinatal service are limited due to lack of availability of in-house anesthesia coverage. This quality improvement project involved development and implementation of a nurse-driven, self-administered, demand-flow nitrous oxide program as an option for pain relief for laboring women in a rural community hospital. Women's Services registered nurses developed the project using an interdisciplinary team approach based on an extensive literature review and consultation with experts across the country. The hospital is part of a large healthcare system; approval was sought and obtained by the system as part of the project. Cost analysis and patient satisfaction data were evaluated. Outcomes were monitored. Approximately one half of the patients who have given birth at the hospital since initiation of the project have used nitrous oxide during labor. The majority of women who participated in a survey after birth found it helpful during mild-to-moderate labor pain. No adverse effects have noted in either the mother or the baby following nitrous oxide use. Initiation and management of nitrous oxide by registered nurses is a safe and cost-effective option for labor pain. It may be especially beneficial in hospitals that do not have 24/7 in-house anesthesia coverage.

  7. Davy comes to America: Woodhouse, Barton, and the nitrous oxide crossing.

    Science.gov (United States)

    Wright, A J

    1995-06-01

    In the final decade of the eighteenth century, a new method of medical treatment appeared in England when physician Thomas Beddoes developed a systematic application of Joseph Priestley's "factitious airs", or gases, to treat consumptive patients. Supported by peers such as Erasmus Darwin and using applications designed for him by James Watt and other inventors, Beddoes combined technological innovation and gas inhalation in an attempt to cure his patients. Late in the decade Beddoes hired young Humphry Davy as his assistant; Davy quickly added nitrous oxide to the armamentarium. The prominent group Davy assembled to help him test nitrous oxide and record their experiences has seldom been equaled in medical history as a research population. Davy left the Pneumatic Institution in March 1801 and joined the staff of the infant Royal Institution in London, but news of the nitrous oxide soon reached American. Physician James Woodhouse, a professor of chemistry at the University of Pennsylvania since July 1795, left in early 1802 for England, where he met Davy. A few years later one of his chemistry students preserved an account of the extensive nitrous oxide trials that took place in Woodhouse's classroom throughout 1807. In that work William Barton discussed and replicates Davy's research and agrees with his conclusions. Such intermittent experimentation continued in the United States and Europe until Horace Well's public demonstration of ether inhalation in January 1845. This paper describes how nitrous oxide inhalation survived in America through the work of Woodhouse and Wells. Traveling showmen like Samuel Colt and Gardner Quincy Colton demonstrated the gas' effects at popular lectures.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Oxygen concentrators performance with nitrous oxide at 50:50 volume

    Directory of Open Access Journals (Sweden)

    Jorge Ronaldo Moll

    2014-06-01

    Full Text Available Background and objectives: Few investigations have addressed the safety of oxygen from concentrators for use in anesthesia in association with nitrous oxide. This study evaluated the percent of oxygen from a concentrator in association with nitrous oxide in a semi-closed rebreathing circuit. Methods: Adult patients undergoing low risk surgery were randomly allocated into two groups, receiving a fresh gas flow of oxygen from concentrators (O293 or of oxygen from concentrators and nitrous oxide (O293N2O. The fraction of inspired oxygen and the percentage of oxygen from fresh gas flow were measured every 10 min. The ratio of FiO2/oxygen concentration delivered was compared at various time intervals and between the groups. Results: Thirty patients were studied in each group. There was no difference in oxygen from concentrators over time for both groups, but there was a significant improvement in the FiO2 (p < 0.001 for O293 group while a significant decline (p < 0.001 for O293N2O. The FiO2/oxygen ratio varied in both groups, reaching a plateau in the O293 group. Pulse oximetry did not fall below 98.5% in either group. Conclusion: The FiO2 in the mixture of O293 and nitrous oxide fell during the observation period although oxygen saturation was higher than 98.5% throughout the study. Concentrators can be considered a stable source of oxygen for use during short anesthetic procedures, either pure or in association with nitrous oxide at 50:50 volume.

  9. Emission of nitrous oxide (N[sub 2]O) from denitrificating wastewater treatment plants. Die Emission von Lachgas (N[sub 2]O) in denitrifizierenden Belebungsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Schulthess, R. von.

    1994-01-01

    The human intrusion in the nitrogen cycle has reached a dimension that disturbs its natural balance. As nitrogen is the growth limiting factor of algae in the sea, the epidemic occurrences of algae in the North- und East Sea in the last years are explained by the increased impact of nitrogen. Switzerland is among other countries responsible for the nitrogen pollutant of the North Sea. Therefore, nitrogen removal (denitrification) has to be incorporated into waste water treatment within the next years. Denitrification is the microbiological reduction of nitrate to elementary nitrogen. Nitrite, nitric oxide and nitrous oxide are intermediate product of this process. Nitrous oxide affects the global climate as a greenhouse gas and via chemical destruction of the ozone layer. Therefore, the waste water treatment plants must operate with a minimum of nitrous oxide emission. The goal of this work was to estimate the N[sub 2]O emission of waste water treatment plants, to identify critical operating conditions and to determine the main mechanisms of the emission. Batch experiments in a bench scale reactor were performed in which under controlled conditions all involved nitrogen species could be analysed. It could be seen that under normal operating conditions no significant amount of nitrous oxide is emitted. However, high nitrite conditions and low oxygen concentrations favour the emission of N[sub 2]O but not of nitric oxide. With a mathematical model that includes the reduction of nitrate, nitrite and nitrous oxide, segments of the experiments can be described satisfactorily. By including the enzyme synthesis and decay of denitrification enzymes in the model the whole experiments can be described. Even when the kinetic parameters could not be determined precisely, some general conclusions could be drawn. (author) figs., tabs., refs.

  10. Simulation of nitrous oxide emissions at field scale using the SPACSYS model

    Science.gov (United States)

    Wu, L.; Rees, R.M.; Tarsitano, D.; Zhang, Xubo; Jones, S.K.; Whitmore, A.P.

    2015-01-01

    Nitrous oxide emitted to the atmosphere via the soil processes of nitrification and denitrification plays an important role in the greenhouse gas balance of the atmosphere and is involved in the destruction of stratospheric ozone. These processes are controlled by biological, physical and chemical factors such as growth and activity of microbes, nitrogen availability, soil temperature and water availability. A comprehensive understanding of these processes embodied in an appropriate model can help develop agricultural mitigation strategies to reduce greenhouse gas emissions, and help with estimating emissions at landscape and regional scales. A detailed module to describe the denitrification and nitrification processes and nitrogenous gas emissions was incorporated into the SPACSYS model to replace an earlier module that used a simplified first-order equation to estimate denitrification and was unable to distinguish the emissions of individual nitrogenous gases. A dataset derived from a Scottish grassland experiment in silage production was used to validate soil moisture in the top 10 cm soil, cut biomass, nitrogen offtake and N2O emissions. The comparison between the simulated and observed data suggested that the new module can provide a good representation of these processes and improve prediction of N2O emissions. The model provides an opportunity to estimate gaseous N emissions under a wide range of management scenarios in agriculture, and synthesises our understanding of the interaction and regulation of the processes. PMID:26026411

  11. From the Gut of an Insect to the Global Climate: Denitrification and Nitrous Oxide Production inside Lake Chironomidae

    DEFF Research Database (Denmark)

    Stief, Peter; Nielsen, Lars Peter; Revsbech, Niels Peter

    2006-01-01

    an environmentally relevant ecosystem function by reducing nitrate to dinitrogen gas. Thereby, they remove inorganic nitrogen that originates from organic matter mineralisation and anthropogenic pollution. Nitrous oxide, a greenhouse gas 300 times more potent than carbon dioxide, is emitted from lakes only...... nitrate pollution of these ecosystems, the gut of benthic invertebrates might constitute an increasingly important yet hitherto overlooked link in the global nitrous oxide budget....... as a minor fraction of the nitrate reduced. However, when lake sediments are densely colonised by macrofauna, the rates of nitrous oxide emission increase significantly. We hypothesise that the guts of bacterivorous macrofauna represent short-term habitats in which high denitrification activity...

  12. How much Nitrous Oxide is produced in cultivation of biofuels on arable land in Sweden?; Hur mycket lustgas blir det vid odling av biobraenslen paa aakermark i Sverige?

    Energy Technology Data Exchange (ETDEWEB)

    Kasimir Klemedtsson, Aasa (Univ. of Goeteborg, Dept. of Earth Sciences, Goeteborg (Sweden). Physical Geography)

    2010-03-15

    Several methods that can be used to estimate the emission of nitrous oxide from arable land are discussed, all of them with their pros and cons. 1 The base for all estimation methods is field measurements, well executed with a technique designed for the production of high quality data. Published field data of good quality were collected from areas in north Europe and America, both from grain and rape crops and unfertilised grasslands where natural background emission is assumed. The compilation shows that grasslands emit in average 0.3 +- 0.1 kg N{sub 2}O-N/ha/year. In crop systems where a high amount of nitrogen is repeatedly added to the soil, the soil N store will contribute to N{sub 2}O emission coming years. This is one reason why emission is higher for unfertilised arable land (where nitrogen have been added previous years) compared to unfertilised grassland, 1 +- 0.1 kg N{sub 2}O-N/ha/year. Fertilised arable lands have higher emission, in average around 3 kg N{sub 2}O-N/ha/year. In comparison, field measurements in Sweden have shown lower emission, 0.6 and 2 kg N{sub 2}O-N/ha/year from clay and sandy soil respectively. 2 The IPCC method is the best known, where the emission from arable land is estimated as a function of added nitrogen. In reality there is no correlation between a low N-addition and the emission of nitrous oxide since the N-addition needs to be high to have influence on the nitrous oxide emission..25 or the new factor 1% of added N has been used in many LCA's as an estimator for nitrous oxide and the uncertainty span of 0,3 and 3% is seldom used. The method underestimates the size of nitrous oxide emission in many systems and cannot estimate a true emission from individual fields. 3 Globally there is a connection between the increase in reactive nitrogen and the increase of atmospheric nitrous oxide, which is the base for a method suggested by Crutzen et al. Nitrous oxide emission has been estimated to be 3-5% of both biological nitrogen

  13. Nitrous oxide emission related to ammonia-oxidizing bacteria and mitigation options from N fertilization in a tropical soil

    NARCIS (Netherlands)

    Soares, Johnny R.; Cassman, N.; Kielak, A.M.; Pijl, A.S.; do Carmo, J.B.; Lourenço, Késia S.; Laanbroek, H.J.; Cantarella, H.; Kuramae, E.E.

    2016-01-01

    Nitrous oxide (N2O) from nitrogen fertilizers applied to sugarcane has high environmental impact on ethanol production. This study aimed to determine the main microbial processes responsible for the N2O emissions from soil fertilized with different N sources, to identify options to mitigate N2O

  14. GOZCARDS Merged Data for Nitrous Oxide Monthly Zonal Means on a Geodetic Latitude and Pressure Grid V1.01

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOZCARDS Merged Data for Nitrous Oxide Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozMmlpN2O) contains zonal means and related...

  15. GOZCARDS Source Data for Nitrous Oxide Monthly Zonal Means on a Geodetic Latitude and Pressure Grid V1.01

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOZCARDS Source Data for Nitrous Oxide Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozSmlpN2O) contains zonal means and related...

  16. Physical mapping of transposon Tn5 insertions defines a gene cluster functional in nitrous oxide respiration by Pseudomonas stutzeri.

    OpenAIRE

    Viebrock, A; Zumft, W G

    1987-01-01

    By transposon Tn5 mutagenesis, 19 strains of Pseudomonas stutzeri were acquired that had defects in nitrous oxide respiration (Nos- phenotype). A physical map of the mutants showed nearly random Tn5 insertions into genomic DNA within a single region ca. 8 kilobases long. Mutants were characterized immunochemically, enzymatically, and chemically. Several functions related to the synthesis and regulation of nitrous oxide reductase were associated with this DNA region, indicating that in P. stut...

  17. Catalytic reduction of nitrous oxide by hydrocarbons over a Fe-zeolite monolith under fluidised bed combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Martinez, E.; Sanchez-Hervas, J.M.; Otero-Ruiz, J. [Departamento de Combustibles Fosiles, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), 28040 Madrid (Spain)

    2004-07-08

    Fluidised bed combustion (FBC) is an important source of nitrous oxide emissions. The catalytic reduction of nitrous oxide with different hydrocarbons was carried out over the catalytic system Fe-ZSM-5 supported on ceramic monoliths, under conditions representative of the off-gases of FBC. The selective catalytic reduction (SCR) of nitrous oxide by propane and propene is activated in the presence of oxygen, whereas its conversion is not affected by the increase of oxygen concentration in the feed gas. The SCR of nitrous oxide by methane is inhibited in the presence of oxygen and the increment of oxygen content in the feed gas leads to a decrease in the catalyst activity and selectivity. Water strongly inhibits the nitrous oxide catalytic reduction independently of the type of hydrocarbon. This effect is more pronounced as water concentration in the process gas increases. Propane resulted to be the most appropriate hydrocarbon of those easily available for the SCR of nitrous oxide over the catalytic system. Methane is little active, whereas propane is slightly more active and selective than propene and results in lower hydrocarbon residual emissions, at oxygen and water levels similar to those found in real combustion off-gases. Furthermore, with respect to methane, propane allows lower reaction temperatures in addition to higher reduction efficiency. Moreover, the emission of unreacted hydrocarbon is higher in the case of methane, whose emission is unwanted, because methane is a greenhouse gas itself.

  18. Compact, Low-power Nitrous Oxide Monitor for Eddy Flux Soil Emission Measurements

    Science.gov (United States)

    Shorter, Joanne; Nelson, David; McManus, Barry; Zahniser, Mark

    2015-04-01

    Nitrous oxide, N2O, is one of the most important greenhouse and ozone-depleting gases. The concentration of N2O in the atmosphere has been increasing at a rate of 0.3% per year, with this rise believed to be largely due to soil emissions and agricultural practices (Park et al. 2011; Park et al. 2012). The eddy covariance technique, which requires fast (~10 Hz) measurement of mixing ratios and wind data, is perhaps the most effective technique available to quantify the exchange of gases between the atmosphere and the biosphere. It is very useful for addressing the high spatial and temporal variability of nitrous oxide emissions from soils. Nitrous oxide monitors appropriate for eddy covariance measurements generally require large flow rates (~10 - 15 slpm) and high speed, high power vacuum pumps (500 lpm, 600 W). These requirements complicate and in some environments prevent successful field deployment. We have addressed this by developing a compact, low-power nitrous oxide monitor for eddy flux or soil chamber measurements with a dramatically reduced sample cell volume. The sample volume is reduced nearly 5 fold (from 500 to 108 cm3) with only a two-fold reduction in optical path length (from 76 m to 36 m). The new multi-pass cell has an aluminum tube insert with a tapered internal volume that follows the mode envelope of the multi-pass spot pattern. This permits the use of a much smaller, lower power pump while still achieving high precision and fast response. Precision of 26 parts per trillion (ppt) in 1 sec was achieved with a 1/e response time of 0.14 s using a relatively low speed vacuum pump (100 lpm, 350 W). Further reductions in cell volume are planned which should permit sensitive eddy covariance measurements of nitrous oxide using an even smaller, lower power pump (60 lpm, 160 W) and modest sample flow rates (~2 slpm). We have also recently studied the application of a standard ARI nitrous oxide monitor to measurement of N2O isotopologues emitted into

  19. Myeloneuropathy following nitrous oxide anesthaesia in a patient with macrocytic anaemia

    Energy Technology Data Exchange (ETDEWEB)

    Sesso, R.M.C.C.; Iunes, Y.; Melo, A.C.P. [Department of Neurology, Instituto de Assistencia Medica ao Servidor Publico Estadual, Sao Paulo (Brazil)

    1999-08-01

    The neurological condition triggered by anaesthesia with nitrous oxide involves the cyanocobalamine pathway and is characterised by progressive demyelination and axonal lesions of the peripheral nerves and cervicothoracic spinal cord (posterior and anterolateral columns) giving a peripheral neuropathy and very frequently subacute combined degeneration of the spinal cord. It is possible to show these demyelinating lesions by MRI of the spine, allowing early diagnosis and follow-up. We describe a case of myeloneuropathy with onset a few hours after nitrous oxide anaesthesia in a patient with macrocytic anaemia and possible subclinical vitamin B{sub 12} deficiency and MRI evidence of a lesion of the cervical spinal cord. Neurological and haematological improvement followed cyanocobalamine replacement. (orig.) With 2 figs., 15 refs.

  20. Protonated Nitrous Oxide, NNOH(+): Fundamental Vibrational Frequencies and Spectroscopic Constants from Quartic Force Fields

    Science.gov (United States)

    Huang, Xinchuan; Fortenberry, Ryan C.; Lee, Timothy J.

    2013-01-01

    The interstellar presence of protonated nitrous oxide has been suspected for some time. Using established high-accuracy quantum chemical techniques, spectroscopic constants and fundamental vibrational frequencies are provided for the lower energy O-protonated isomer of this cation and its deuterated isotopologue. The vibrationally-averaged B0 and C0 rotational constants are within 6 MHz of their experimental values and the D(subJ) quartic distortion constants agree with experiment to within 3%. The known gas phase O-H stretch of NNOH(+) is 3330.91 cm(exp-1), and the vibrational configuration interaction computed result is 3330.9 cm(exp-1). Other spectroscopic constants are also provided, as are the rest of the fundamental vibrational frequencies for NNOH(+) and its deuterated isotopologue. This high-accuracy data should serve to better inform future observational or experimental studies of the rovibrational bands of protonated nitrous oxide in the ISM and the laboratory.

  1. Treatment-Resistant Major Depression: Rationale for NMDA Receptors as Targets and Nitrous Oxide as Therapy

    Science.gov (United States)

    Zorumski, Charles F.; Nagele, Peter; Mennerick, Steven; Conway, Charles R.

    2015-01-01

    Major depressive disorder (MDD) remains a huge personal and societal encumbrance. Particularly burdensome is a virulent subtype of MDD, treatment resistant major depression (TMRD), which afflicts 15–30% of MDD patients. There has been recent interest in N-methyl-d-aspartate receptors (NMDARs) as targets for treatment of MDD and perhaps TMRD. To date, most pre-clinical and clinical studies have focused on ketamine, although psychotomimetic and other side effects may limit ketamine’s utility. These considerations prompted a recent promising pilot clinical trial of nitrous oxide, an NMDAR antagonist that acts through a mechanism distinct from that of ketamine, in patients with severe TRMD. In this paper, we review the clinical picture of TRMD as a subtype of MDD, the evolution of ketamine as a fast-acting antidepressant, and clinical and basic science studies supporting the possible use of nitrous oxide as a rapid antidepressant. PMID:26696909

  2. Aeration Strategies To Mitigate Nitrous Oxide Emissions from Single-Stage Nitritation/Anammox Reactors

    DEFF Research Database (Denmark)

    Domingo Felez, Carlos; Mutlu, A. Gizem; Jensen, Marlene Mark

    2014-01-01

    Autotrophic nitrogen removal is regarded as a resource efficient process to manage nitrogen-rich residual streams. However, nitrous oxide emissions of these processes are poorly documented and strategies to mitigate emissions unknown. In this study, two sequencing batch reactors performing single......-stage nitritation/anammox were operated under different aeration strategies, gradually adjusted over six months. At constant but limiting oxygen loading, synthetic reject water was fed (0.75g-N/L.d) and high nitrogen removal efficiencies (83 +/- 5 and 88 +/- 2%) obtained. Dynamics of liquid phase nitrous (N2O......) and nitric oxide (NO) concentrations were monitored and N2O emissions calculated. Significant decreases in N2O emissions were obtained when the frequency of aeration was increased while maintaining a constant air flow rate (from >6 to 1.7% Delta N2O/Delta TN). However, no significant effect on the emissions...

  3. Determination of emissions of methane and nitrous oxide in rice plantations in Guanacaste, Costa Rica

    Directory of Open Access Journals (Sweden)

    Jorge Herrera

    2013-12-01

    Full Text Available Methane and nitrous oxide emissions fluxes were measured in 10 rice plantations located in Liberia, Guanacaste, working at least with 04 varieties of rice and two types of soil in the period August 2012 - April 2013. For the determination of flows static camera technique were used taking four air gas samples located in the headspace of the chamber using a plastic syringe of 12 ml at 0, 10, 20 and 30 min after camera location. The gas samples were analyzed with a gas chromatograph, equipped with FID and ECD. Averages of flow methane and nitrous oxide were recorded between 0,12 to 1,9 kg ha-1d-1 and 0,11 - 1,1 mg ha-1d-1, respectively, and no significant difference was found (p < 0,05 in the values between different rice varieties and soil types subject experimental design.

  4. Prophylactic Modulation of Methane and Nitrous Oxide Emitted from Ruminants Livestock for Sustainable Animal Agriculture

    OpenAIRE

    J. Takahashi

    2014-01-01

    Major greenhouse gases (GHG) attributed to animal agriculture sector are methane (CH4) and nitrous oxide (N2O), either generated from enteric fermentation or manure. The abatement mechanism of rumen CH4 emission may be divided to direct and indirect suppression to methanogens in the rumen.The most significant strategy to mitigate ruminal CH4 emission in indirect manner is to promote alternative metabolic pathway to dispose of the reducing power, competing with methanogenesis for H2 uptake. Th...

  5. Evaluation of nitrous oxide-oxygen and triclofos sodium as conscious sedative agents

    Directory of Open Access Journals (Sweden)

    Priya Subramaniam

    2017-01-01

    Full Text Available Background: Conscious sedation is used in the pediatric dentistry to reduce fear and anxiety in children and promote favorable treatment outcomes. To achieve them, the primary clinical need is for a well-tolerated, effective, and expedient analgesic and sedative agent that is safe to use. Aim: The aim of the present study was to evaluate the efficacy of nitrous oxide-oxygen and triclofos sodium as conscious sedative agents in 5–10-year-old children. Methodology: Sixty children aged 5–10 years showing anxious, uncooperative, and apprehensive behavior were randomly divided and assigned into two groups (Groups A and B such that Group A received 40% nitrous oxide-60% oxygen and Group B received triclofos sodium in the dose of 70 mg/kg body weight, given 30 min before the treatment procedure. During the whole course of sedation procedure, the response of the child was assessed using Houpt's behavior rating scale. The acceptance of route of drug administration by the patient and parent was also assessed. Data obtained were statistically evaluated using the Mann–Whitney U-test and Chi-square test. Results: Children sedated with triclofos sodium were significantly more drowsy and disoriented compared to those sedated with nitrous oxide. The overall behavior of children in both the groups was similar. Good parental acceptance was observed for both the routes of administration. Patients accepted the oral route significantly better than inhalation route. Conclusion: Both nitrous oxide-oxygen and triclofos sodium were observed to be effective sedative agents, for successful and safe use in 5–10-year-old dental patients. Patients showed a good acceptance of the oral route compared to the inhalation route for sedation.

  6. Synergistic growth inhibiting effect of nitrous oxide and cycloleucine in experimental rat leukaemia.

    OpenAIRE

    Kroes, A. C.; Lindemans, J.; Abels, J.

    1984-01-01

    Nitrous oxide (N2O) inactivates the vitamin B12-dependent enzyme methionine synthetase with subsequent impairment of folate metabolism and a reduction of cellular proliferation. Indications exist that this effect is antagonized by S-adenosylmethionine (SAM), and it was investigated whether combination with an inhibitor of SAM synthesis, cycloleucine, would result in increased inhibition of growth in rat leukaemia model (BNML). Leukaemic growth was compared in untreated rats, in rats treated w...

  7. Prophylactic Modulation of Methane and Nitrous Oxide Emitted From Ruminants Livestock for Sustainable Animal Agriculture (REVIEW)

    OpenAIRE

    Takahashi, J.

    2014-01-01

    Major greenhouse gases (GHG) attributed to animal agriculture sector are methane (CH4) and nitrous oxide (N2O), either generated from enteric fermentation or manure. The abatement mechanism of rumen CH4 emission may be divided to direct and indirect suppression to methanogens in the rumen.The most significant strategy to mitigate ruminal CH4 emission in indirect manner is to promote alternative metabolic pathway to dispose of the reducing power, competing with methanogenesis for H2 uptake. Th...

  8. Nitrous Oxide Persistently Alleviates Pain Hypersensitivity in Neuropathic Rats: A Dose-Dependent Effect

    Directory of Open Access Journals (Sweden)

    Meric Ben Boujema

    2015-01-01

    Full Text Available BACKGROUND: Despite numerous pharmacological approaches, there are no common analgesic drugs that produce meaningful relief for the majority of patients with neuropathic pain. Although nitrous oxide (N2O is a weak analgesic that acts via opioid-dependent mechanisms, it is also an antagonist of the N-methyl-D-aspartate receptor (NMDAR. The NMDAR plays a critical role in the development of pain sensitization induced by nerve injury.

  9. Cryptogamic stem covers may contribute to nitrous oxide consumption by mature beech trees

    Czech Academy of Sciences Publication Activity Database

    Macháčová, Kateřina; Maier, M.; Svobodová, Kateřina; Lang, F.; Urban, Otmar

    2017-01-01

    Roč. 7, OCT (2017), č. článku 13243. ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LO1415; GA MŠk(CZ) LM2015061; GA ČR(CZ) GJ17-18112Y Institutional support: RVO:67179843 Keywords : nitrous oxide * N2O * field conditions * cryptogamic stem Subject RIV: CE - Biochemistry Impact factor: 4.259, year: 2016

  10. Tidal variability in methane and nitrous oxide emissions along a subtropical estuarine gradient

    Science.gov (United States)

    Sturm, Katrin; Werner, Ursula; Grinham, Alistair; Yuan, Zhiguo

    2017-06-01

    This study investigates the tidal variability in methane (CH4) and nitrous oxide (N2O) emissions along a gradient of the subtropical Brisbane River estuary. Sampling was conducted at the upper, middle and lower reaches over two tidal cycles in 2013 and 2014. Methane and N2O emissions varied significantly over tidal cycles at all sites. Methane and N2O emissions measured at all locations and in both campaigns varied substantially in time, with the maximum to minimum flux ratio in a cycle varying between 2.5 - 9 and 1.7-4.7 times, respectively. Methane emissions peaked just before or at slack tides. In comparison, no clear patterns were observed between the N2O emissions and the tidal cycle despite there being large variations in N2O emissions in some cases. Methane concentrations were elevated during low tides whereas N2O concentrations showed no clear pattern over the tidal cycle. Surface water concentrations and tidal currents played important roles in CH4 and N2O emissions, but wind did not. Our findings show that measurements at a single point in time and site would result in significant errors in CH4 and N2O emission estimates. An adequate and careful sampling scheme is required to capture spatial and temporal variations of CH4 and N2O emissions and surface water concentrations which should cover at least one tidal cycle in different estuarine sections.

  11. Modeling nitrous oxide production and reduction in soil through explicit representation of denitrification enzyme kinetics.

    Science.gov (United States)

    Zheng, Jianqiu; Doskey, Paul V

    2015-02-17

    An enzyme-explicit denitrification model with representations for pre- and de novo synthesized enzymes was developed to improve predictions of nitrous oxide (N2O) accumulations in soil and emissions from the surface. The metabolic model of denitrification is based on dual-substrate utilization and Monod growth kinetics. Enzyme synthesis/activation was incorporated into each sequential reduction step of denitrification to regulate dynamics of the denitrifier population and the active enzyme pool, which controlled the rate function. Parameterizations were developed from observations of the dynamics of N2O production and reduction in soil incubation experiments. The model successfully reproduced the dynamics of N2O and N2 accumulation in the incubations and revealed an important regulatory effect of denitrification enzyme kinetics on the accumulation of denitrification products. Pre-synthesized denitrification enzymes contributed 20, 13, 43, and 62% of N2O that accumulated in 48 h incubations of soil collected from depths of 0-5, 5-10, 10-15, and 15-25 cm, respectively. An enzyme activity function (E) was defined to estimate the relative concentration of active enzymes and variation in response to environmental conditions. The value of E allows for activities of pre-synthesized denitrification enzymes to be differentiated from de novo synthesized enzymes. Incorporating explicit representations of denitrification enzyme kinetics into biogeochemical models is a promising approach for accurately simulating dynamics of the production and reduction of N2O in soils.

  12. Nitrous Oxide and Dinitrogen: The Missing Flux in Nitrogen Budgets of Forested Catchments?

    Science.gov (United States)

    Enanga, Eric M; Casson, Nora J; Fairweather, Tarrah A; Creed, Irena F

    2017-06-06

    Most forest nitrogen budgets are imbalanced, with nitrogen inputs exceeding nitrogen outputs. The denitrification products nitrous oxide (N2O) and dinitrogen (N2) represent often-unmeasured fluxes that may close the gap between explained nitrogen inputs and outputs. Gaseous N2O and N2 effluxes, dissolved N2O flux, and traditionally measured dissolved nitrogen species (i.e., nitrate, ammonium, and dissolved organic nitrogen) were estimated to account for the annual nitrogen output along hillslope gradients from two catchments in a temperate forest. Adding N2O and N2 effluxes to catchment nitrogen output not only reduced the discrepancy between nitrogen inputs and outputs (9.9 kg ha-1 yr-1 and 6.5 or 6.3 kg ha-1 yr-1, respectively), but also between nitrogen outputs from two catchments with different topographies (6.5 kg ha-1 yr-1 for the catchment with a large wetland, 6.3 kg ha-1 yr-1 for the catchment with a very small wetland). Dissolved N2O comprised a very small portion of the annual nitrogen outputs. Nitrogen inputs exceeded nitrogen outputs throughout the year except during spring runoff, and also during autumn storms in the catchment with the large wetland. Failing to account for denitrification products, especially during summer rainfall events, may lead to underestimation of annual nitrogen losses.

  13. Nitrous oxide emissions from a large, impounded river: the Ohio River.

    Science.gov (United States)

    Beaulieu, J J; Shuster, W D; Rebholz, J A

    2010-10-01

    Models suggest that microbial activity in streams and rivers is a globally significant source of anthropogenic nitrous oxide (N(2)O), a potent greenhouse gas, and the leading cause of stratospheric ozone destruction. However, model estimates of N(2)O emissions are poorly constrained due to a lack of direct measurements of microbial N(2)O production and consequent emissions, particularly from large rivers. We report the first N(2)O budget for a large, nitrogen enriched river, based on direct measurements of N(2)O emissions from the water surface and N(2)O production in the sediments and water column. Maximum N(2)O emissions occurred downstream from Cincinnati, Ohio, a major urban center on the river, due to direct inputs of N(2)O from wastewater treatment plant effluent and higher rates of in situ production. Microbial activity in the water column and sediments was a source of N(2)O, and water column production rates were nearly double those of the sediments. Emissions exhibited strong seasonality with the highest rates observed during the summer and lowest during the winter. Our results indicate N(2)O dynamics in large temperate rivers may be characterized by strong seasonal cycles and production in the pelagic zone.

  14. Statistical analysis of nitrous oxide emission factors from pastoral agriculture field trials conducted in New Zealand.

    Science.gov (United States)

    Kelliher, F M; Cox, N; van der Weerden, T J; de Klein, C A M; Luo, J; Cameron, K C; Di, H J; Giltrap, D; Rys, G

    2014-03-01

    Between 11 May 2000 and 31 January 2013, 185 field trials were conducted across New Zealand to measure the direct nitrous oxide (N2O) emission factors (EF) from nitrogen (N) sources applied to pastoral soils. The log(EF) data were analysed statistically using a restricted maximum likelihood (REML) method. To estimate mean EF values for each N source, best linear unbiased predictors (BLUPs) were calculated. For lowland soils, mean EFs for dairy cattle urine and dung, sheep urine and dung and urea fertiliser were 1.16 ± 0.19% and 0.23 ± 0.05%, 0.55 ± 0.19% and 0.08 ± 0.02% and 0.48 ± 0.13%, respectively, each significantly different from one another (p 12°, mean EFs were significantly lower. Thus, urine and dung EFs should be disaggregated for sheep and cattle as well as accounting for terrain. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Biogeochemical controls and isotopic signatures of nitrous oxide production by a marine ammonia-oxidizing bacterium

    Directory of Open Access Journals (Sweden)

    C. H. Frame

    2010-09-01

    Full Text Available Nitrous oxide (N2O is a trace gas that contributes to the greenhouse effect and stratospheric ozone depletion. The N2O yield from nitrification (moles N2O-N produced per mole ammonium-N consumed has been used to estimate marine N2O production rates from measured nitrification rates and global estimates of oceanic export production. However, the N2O yield from nitrification is not constant. Previous culture-based measurements indicate that N2O yield increases as oxygen (O2 concentration decreases and as nitrite (NO2 concentration increases. Here, we have measured yields of N2O from cultures of the marine β-proteobacterium Nitrosomonas marina C-113a as they grew on low-ammonium (50 μM media. These yields, which were typically between 4 × 10−4 and 7 × 10−4 for cultures with cell densities between 2 × 102 and 2.1 × 104 cells ml−1, were lower than previous reports for ammonia-oxidizing bacteria. The observed impact of O2 concentration on yield was also smaller than previously reported under all conditions except at high starting cell densities (1.5 × 106 cells ml−1, where 160-fold higher yields were observed at 0.5% O2 (5.1 μM dissolved O2 compared with 20% O2 (203 μM dissolved O2. At lower cell densities (2 × 102 and 2.1 × 104 cells ml−1, cultures grown under 0.5% O2 had yields that were only 1.25- to 1.73-fold higher than cultures grown under 20% O2. Thus, previously reported many-fold increases in N2O yield with dropping O2 could be reproduced only at cell densities that far exceeded those of ammonia oxidizers in the ocean. The presence of excess NO2 (up to 1 mM in the growth

  16. Interest of 50% nitrous oxide and oxygen premix sedation in gerodontology

    Directory of Open Access Journals (Sweden)

    Emmanuel Nicolas

    2008-12-01

    Full Text Available Emmanuel Nicolas1,2, Claire Lassauzay1,21CHU de Clermont-Ferrand, 63000 Clermont-Ferrand, France; 2Université Clermont 1, EA 3847, Faculty of Dentistry, 63000 Clermont-Ferrand, FranceAbstract: Elderly patients presenting cardiovascular, respiratory, or neurological disorders require a specific dental care approach, especially patients presenting Alzheimer’s disease. Sedative procedures can prevent dental care-induced stress, even when there is effective pain control, but they have to be adapted to accommodate age-induced physiological modifications, age-related pathologies, and the concomitant treatments. In many situations, routine sedative prescriptions for dental care, such as benzodiazepine or antihistaminics, are not recommended for these patients. Nitrous oxide inhalation together with a specific behavioral threshold is currently the only sedative procedure adapted to cognitively-impaired elderly patients. Nitrous oxide is able to curb stress and its cardiovascular consequences, improve oxygenation, and optimize cooperation during dental care, making not only rehabilitation treatments but also routine dental care a viable option.Keywords: nitrous oxide, oxygen, premix, sedation, gerodontology, dental care

  17. Treatment of alcohol withdrawal syndrome with carbamazepine, gabapentin, and nitrous oxide.

    Science.gov (United States)

    Prince, Valerie; Turpin, Kelly R

    2008-06-01

    To evaluate the potential use of carbamazepine, gabapentin, and nitrous oxide as alternatives to symptom-triggered benzodiazepine administration for the treatment of alcohol withdrawal syndrome (AWS), a literature review was conducted. English-language reports of clinical trials of these agents in AWS, particularly trials that compared them with benzodiazepines or anticonvulsants or used them as benzodiazepine-sparing therapy, were reviewed. Six randomized, double-blind trials compared carbamazepine with agents used in the United States. The results suggest that carbamazepine may be useful for this indication, particularly in outpatient settings, although adverse effects and drug interactions may limit its usefulness. The role of gabapentin is unclear because of the lack of randomized, double-blind, controlled trials and the conflicting results of existing case series and open-label trials. Two poorly designed trials of nitrous oxide had conflicting results. Because of the limitations in evidence accrued so far, the routine use of carbamazepine and gabapentin for the treatment of AWS cannot be recommended, and nitrous oxide should be avoided for this indication.

  18. Nitrogen transformations and nitrous oxide flux in a tropical deciduous forest in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Mendez, G.; Maass, J.M.; Matson, P.A.; Vitousek, P.M. (Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Centro de Ecologia)

    1991-01-01

    Emissions of nitrous oxide and soil nitrogen pools and transformations were measured over an annual cycle in two forests and one pasture in tropical deciduous forest near Chamela, Mexico. Nitrous oxide flux was moderately high 0.5-2.5 ng cm{sup -2}h{sup -1} during the wet season and low ({lt}0.3 ng cm{sup -2}h{sup -1}) during the dry season. Annual emissions of nitrogen as nitrous oxide were calculated to be 0.5-0.7 kg ha{sup -1}y{sup -1}, with no substantial difference between the forests and pasture. Wetting of dry soil caused a large but short-lived pulse of N{sub 2}O flux that accounted for {lt}2% of annual flux. Variation in soil water through the season was the primary controlling factor for pool sizes of ammonium and nitrate, nitrogen transformations, and N{sub 2}O flux. 26 refs., 4 figs., 3 tabs.

  19. Measurement of nitrous oxide concentrations in a simulated post anesthesia care unit environment.

    Science.gov (United States)

    Austin, P R; Austin, P J

    1996-08-01

    The postanesthesia care unit (PACU) nurse works in close proximity to patients during early stages of recovery. It is during this time that the patient exhales the highest levels of anesthetic gases. The National Institute for Occupational Health and Safety has established standards for exposure to waste anesthetic gases which state that sampling should be done in the breathing zone of those most heavily exposed. Thus, it is important that a sampling methodology, data acquisition system, and statistical analysis technique be developed which accurately measures waste anesthetic gas levels at a point representing the breathing zone of nurses providing bedside care. A study was conducted to obtain an understanding of how the concentration of nitrous oxide varies with distance from a recovering patient. The study found that concentration of nitrous oxide decreases with distance from the patient; the patient's respiration increases the level of nitrous oxide at the location of the nurse; and the respiration of the nurse pulls the flow field toward them, increasing their exposure to the gas. The results show the inadequacy of attempting to measure levels of gas exposure for PACU nurses by a sampling protocol which calls for samples taken at random points in the room.

  20. Kinetics of abiotic nitrous oxide production via oxidation of hydroxylamine by particulate metals in seawater

    Science.gov (United States)

    Cavazos, A. R.; Taillefert, M.; Glass, J. B.

    2016-12-01

    The oceans are a significant of nitrous oxide (N2O) to the atmosphere. Current models of global oceanic N2­O flux focus on microbial N2O cycling and often ignore abiotic reactions, such as the thermodynamically favorable oxidation of the nitrification intermediate hydroxylamine (NH2OH) by Mn(IV) or Fe(III). At circumneutral pH, NH2OH oxidation is more thermodynamically favorable via Mn(IV) than Fe(III) reduction. We characterized the kinetics of NH2OH oxidation in synthetic ocean water at pH 5.1-8.8 using microsensor electrodes to measure real-time N2O production. N2O production rates and yield were greater when NH2OH was oxidized by Mn(IV) than Fe(III). Accordingly, the reduction of Mn(IV) was first order with respect to NH2OH whereas the reduction of Fe(III) was zero order with respect to NH2OH. Interestingly, the order of the reaction with respect to Mn(IV) appears to be negative whereas the reaction is second order with respect to Fe(III). The inverse order with respect to Mn(IV) may be due to the aggregation of particles in seawater, which decreases their surface area and changes their reactivity. Finally, the reaction is first order with respect to protons with Fe(III) as the oxidant but zero order with Mn(IV). The stronger effect of the pH on the reaction with Fe(III) as the oxidant compared to Mn(IV) reflects the stoichiometry of these two reactions, as each mole of N2O produced by Fe(III) reduction consumes eight protons while each mole of N2O produced with Mn(IV) as the oxidant requires only four protons. Our data show that abiotic NH2OH oxidation by Mn(IV) or Fe(III) particles may represent a significant source of N2O in seawater. These findings suggest that abiotic N2O production in marine waters may be significant in areas of the oceans where particulate metals originating from aerosols, dust, or rivers may react with NH2OH released from ammonia-oxidizing microorganisms.

  1. Soil fluxes of methane, nitrous oxide, and nitric oxide from aggrading forests in coastal Oregon

    Science.gov (United States)

    Erickson, Heather E.; Perakis, Steven S.

    2014-01-01

    Soil exchanges of greenhouse and other gases are poorly known for Pacific Northwest forests where gradients in nutrient availability and soil moisture may contribute to large variations in fluxes. Here we report fluxes of methane (CH4), nitrous oxide (N2O), and nitric oxide (NO) over multiple seasons from three naturally N-rich, aggrading forests of coastal Oregon, USA. Mean methane uptake rates (3.2 mg CH4 m−2 d−1) were high compared with forests globally, negatively related to water-filled pore space (WFPS), but unrelated to N availability or temperature. Emissions of NO (6.0 μg NO–N m−2 h−1) exceeded N2O (1.4 μg N2O–N m−2 h−1), except when WFPS surpassed 55%. Spatial variation in NO fluxes correlated positively with soil nitrate concentrations (which generally exceeded ammonium concentrations, indicating the overall high N status for the sites) and negatively with soil pH, and at one site increased with basal area of N2-fixing red alder. Combined NO and N2O emissions were greatest from the site with highest annual net N mineralization and lowest needle litterfall C/N. Our findings of high CH4 uptake and NO/N2O ratios generally >1 most likely reflect the high porosity of the andic soils underlying the widespread regenerating forests in this seasonally wet region.

  2. Phenol by direct hydroxylation of benzene with nitrous oxide - role of surface oxygen species in the reaction pathways

    Energy Technology Data Exchange (ETDEWEB)

    Reitzmann, A.; Klemm, E.; Emig, G. [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Technische Chemie 1; Buchholz, S.A.; Zanthoff, H.W. [Bochum Univ. (Germany). Inst. of Technical Chemistry

    1998-12-31

    Transient experiments in a Temporal Analysis of Products (TAP) Reactor were performed to elucidate the role of surface oyxgen species in the oxidation of benzene to phenol on ZSM-5 type zeolites with nitrous oxide as a selective oxidant. It was shown by puls experiments with nitrous oxide that the mean lifetime of the generated surface oxygen species is between 0.2s at 500 C and about 4.2 s at 400 C. Afterwards the surface oxygen species desorb as molecular oxygen into the gas phase where total oxidation will take place if hydrocarbons are present. Dual puls experiments consisting of a nitrous oxide puls followed by a benzene puls allowed studying the reactivity of the surface oxygen species formed during the first puls. The observation of the phenol formation was impeded due to the strong sorption of phenol. Multipulse experiments were necessary to reach a pseudo steady state phenol yield. (orig.)

  3. Simulation of nitrous oxide emissions at field scale using the SPACSYS model

    Energy Technology Data Exchange (ETDEWEB)

    Wu, L., E-mail: Lianhai.Wu@rothamsted.ac.uk [Sustainable Soils and Grassland Systems Department, Rothamsted Research, North Wyke, Okehampton EX20 2SB (United Kingdom); Rees, R.M.; Tarsitano, D. [Scotland' s Rural College (SRUC), West Mains Road, Edinburgh EH9 3JG (United Kingdom); Zhang, Xubo [Sustainable Soils and Grassland Systems Department, Rothamsted Research, North Wyke, Okehampton EX20 2SB (United Kingdom); Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081 (China); Jones, S.K. [Scotland' s Rural College (SRUC), West Mains Road, Edinburgh EH9 3JG (United Kingdom); Whitmore, A.P. [Sustainable Soils Grassland Systems Department, Rothamsted Research, Harpenden AL5 2JQ (United Kingdom)

    2015-10-15

    Nitrous oxide emitted to the atmosphere via the soil processes of nitrification and denitrification plays an important role in the greenhouse gas balance of the atmosphere and is involved in the destruction of stratospheric ozone. These processes are controlled by biological, physical and chemical factors such as growth and activity of microbes, nitrogen availability, soil temperature and water availability. A comprehensive understanding of these processes embodied in an appropriate model can help develop agricultural mitigation strategies to reduce greenhouse gas emissions, and help with estimating emissions at landscape and regional scales. A detailed module to describe the denitrification and nitrification processes and nitrogenous gas emissions was incorporated into the SPACSYS model to replace an earlier module that used a simplified first-order equation to estimate denitrification and was unable to distinguish the emissions of individual nitrogenous gases. A dataset derived from a Scottish grassland experiment in silage production was used to validate soil moisture in the top 10 cm soil, cut biomass, nitrogen offtake and N{sub 2}O emissions. The comparison between the simulated and observed data suggested that the new module can provide a good representation of these processes and improve prediction of N{sub 2}O emissions. The model provides an opportunity to estimate gaseous N emissions under a wide range of management scenarios in agriculture, and synthesises our understanding of the interaction and regulation of the processes. - Highlights: • Microbe-controlled denitrification and N{sub 2}O emissions were built in SPACSYS. • Simulated outputs agreed well with a Scottish grassland dataset. • The simulated emission factors vary with climate, management and forms of applied N. • SPACSYS is capable of simulating the components in C and N cycling in grassland.

  4. Management matters: Testing a mitigation strategy of nitrous oxide emissions on managed grassland

    Science.gov (United States)

    Fuchs, Kathrin; Hörtnagl, Lukas; Eugster, Werner; Koller, Patrick; Käslin, Florian; Merbold, Lutz

    2017-04-01

    The magnitude of greenhouse gas (GHG) exchange between managed grasslands and the atmosphere depends besides climate predominantly on management practices. While natural or extensively managed grasslands are known to function as GHG sinks, intensively managed grasslands are characterized by substantial nitrous oxide (N2O) emissions diminishing their sink function. One potential N2O mitigation strategy is to reduce the required amount of nitrogen (N) fertilizer input by using biological nitrogen fixation (BNF) via legumes. However, the effect of legumes on nitrous oxide emissions is still not fully understood. In this study we quantify net GHG fluxes from two differently managed grassland parcels (mitigation, control) and relate our results to productivity (yields). In addition, we aim at revealing the influence of various driver variables on N2O exchange. Our experimental setup consisted of an eddy covariance tower that measured the net exchange of the three major anthropogenic GHGs, nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2). Both grassland parcels can be covered with this tower due to two prevailing wind directions. GHG flux measurements were accompanied by measurements of commonly known driver variables such as water filled pore space, soil temperature, soil oxygen concentrations and mineral N to disentangle the soil meteorological influence of N2O fluxes from human drivers. Following organic fertilizer application, we measured elevated N2O emissions (>1 nmol m-2 s-1) at the control parcel and unchanged N2O emissions at the treatment parcel. Net annual fluxes were 54% and 50% lower at the experimental parcel in 2015 and 2016, respectively. Annual yields did not significantly differ between parcels, but were slightly lower at the experimental parcel compared to the control parcel. Significantly lower nitrous oxide fluxes under experimental management indicate that nitrous oxide emissions can be effectively reduced at very low costs with a clover

  5. Nitrous oxide production in intermittently aerated Partial Nitritation-Anammox reactor: oxic N2O production dominates and relates with ammonia removal rate

    DEFF Research Database (Denmark)

    Blum, Jan-Michael; Jensen, Marlene Mark; Smets, Barth F.

    2018-01-01

    to an effective control of accumulation of nitrogen intermediates. However, due to frequent changes of redox conditions under intermittent aeration regimes, nitrous oxide production and emissions are dynamic. In this study the production and emission dynamics of nitrous oxide in an intermittently aerated......-production rates were observed at ammonia removal rates below 5 mg NH3-N*gVSS−1*L−1, when the fraction of nitrous oxide produced was 0.011 ± 0.004% (per ammonia removed). Based on the nitrous oxide dynamics and correlations, reactor operation at relatively low nitrogen loadings (below 100 mg NH4+-N*L−1), ammonia...

  6. Reevaluation of the global warming impacts of algae-derived biofuels to account for possible contributions of nitrous oxide.

    Science.gov (United States)

    Bauer, Sarah K; Grotz, Lara S; Connelly, Elizabeth B; Colosi, Lisa M

    2016-10-01

    The environmental impacts of algae biofuels have been evaluated by life-cycle assessment (LCA); however, these analyses have overlooked nitrous oxide (N2O), a potent greenhouse gas. A literature analysis was performed to estimate algal N2O emissions and assess the impacts of growth conditions on flux magnitudes. Nitrogen source and dissolved oxygen concentration were identified as possible key contributors; therefore, their individual and combined impacts were evaluated using bench-scale experiments. It was observed that maximum N2O emissions (77.5μg/galgae/day) occur under anoxic conditions with nitrite. Conversely, minimum emissions (6.25μg/galgae/day) occur under oxic conditions with nitrate. Aggregated N2O flux estimates were then incorporated into a LCA framework for algae biodiesel. Accounting for "low" N2O emissions mediated no significant increase (algae biofuels. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Analysis of High Frequency Site-Specific Nitrogen and Oxygen Isotopic Composition of Atmospheric Nitrous Oxide at Mace Head, Ireland

    Science.gov (United States)

    McClellan, M. J.; Harris, E. J.; Olszewski, W.; Ono, S.; Prinn, R. G.

    2014-12-01

    Atmospheric nitrous oxide (N2O) significantly impacts Earth's climate due to its dual role as an inert potent greenhouse gas in the troposphere and as a reactive source of ozone-destroying nitrogen oxides in the stratosphere. However, there remain significant uncertainties in the global budget of this gas. The marked spatial divide in its reactivity means that all stages in the N2O life cycle—emission, transport, and destruction—must be examined to understand the overall effect of N2O on climate. Source and sink processes of N2O lead to varying concentrations of N2O isotopologues (14N14N16O, 14N15N16O, 15N14N16O, and 14N14N18O being measured) due to preferential isotopic production and elimination in different environments. Estimation of source and sink fluxes can be improved by combining isotopically resolved N2O observations with simulations using a chemical transport model with reanalysis meteorology and treatments of isotopic signatures of specific surface sources and stratospheric intrusions. We present the first few months of site-specific nitrogen and oxygen isotopic composition data from the Stheno-TILDAS instrument (Harris et al, 2013) at Mace Head, Ireland and compare these to results from MOZART-4 (Model for Ozone and Related Chemical Tracers, version 4) chemical transport model runs including N2O isotopic fractionation processes and reanalysis meterological fields (NCEP/NCAR, MERRA, and GEOS-5). This study forms the basis for future inverse modeling experiments that will improve the accuracy of isotopically differentiated N2O emission and loss estimates. Ref: Harris, E., D. Nelson, W. Olszewski, M. Zahniser, K. Potter, B. McManus, A. Whitehill, R. Prinn, and S. Ono, Development of a spectroscopic technique for continuous online monitoring of oxygen and site-specific nitrogen isotopic composition of atmospheric nitrous oxide, Analytical Chemistry, 2013; DOI: 10.1021/ac403606u.

  8. Extending the benchmark simulation model no2 with processes for nitrous oxide production and side-stream nitrogen removal

    DEFF Research Database (Denmark)

    Boiocchi, Riccardo; Sin, Gürkan; Gernaey, Krist V.

    2015-01-01

    In this work the Benchmark Simulation Model No.2 is extended with processes for nitrous oxide production and for side-stream partial nitritation/Anammox (PN/A) treatment. For these extensions the Activated Sludge Model for Greenhouse gases No.1 was used to describe the main waterline, whereas...... increased the total nitrogen removal by 10%; (ii) reduced the aeration demand by 16% compared to the base case, and (iii) the activity of ammonia-oxidizing bacteria is most influencing nitrous oxide emissions. The extended model provides a simulation platform to generate, test and compare novel control...... strategies to improve operation performance and to meet the new plant performance criteria such as minimization of greenhouse gas (in particular of nitrous oxide) emissions....

  9. Effect of nitrous oxide on the efficacy of the inferior alveolar nerve block in patients with symptomatic irreversible pulpitis.

    Science.gov (United States)

    Stanley, William; Drum, Melissa; Nusstein, John; Reader, Al; Beck, Mike

    2012-05-01

    The inferior alveolar nerve (IAN) block does not always result in successful pulpal anesthesia. Anesthetic success rates might be affected by increased anxiety. Nitrous oxide has been shown to have both anxiolytic and analgesic properties. Therefore, the purpose of this prospective, randomized, double-blind, placebo-controlled study was to determine the effect of nitrous oxide on the anesthetic success of the IAN block in patients experiencing symptomatic irreversible pulpitis. One hundred emergency patients diagnosed with symptomatic irreversible pulpitis of a mandibular posterior tooth were enrolled in this study. Each patient was randomly assigned to receive an inhalation regimen of nitrous oxide/oxygen mix or room air/oxygen mix (placebo) 5 minutes before the administration of the IAN block. Endodontic access was begun 15 minutes after completion of the IAN block, and all patients had profound lip numbness. Success was defined as no or mild pain (visual analog scale recordings) on access or instrumentation. The success rate for the IAN block was 50% for the nitrous oxide group and 28% for the placebo group. There was a statistically significant difference between the 2 groups (P = .024). For mandibular teeth diagnosed with symptomatic irreversible pulpitis, administration of 30%-50% nitrous oxide resulted in a statistically significant increase in the success of the IAN block compared with room air/oxygen. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  10. Subtropical freshwater storages: a major source of nitrous oxide and methane?

    Science.gov (United States)

    Sturm, Katrin; Grinham, Alistair; Yuan, Zhiguo

    2013-04-01

    Studies of greenhouse gas cycling in subtropical water bodies, particularly in the Southern Hemisphere, are very limited. This represents an important gap in our understanding of global emissions as the higher temperatures experienced in the subtropics will likely accelerate greenhouse gas production and consumption. Critical to understanding the net impact of these accelerated rates are detailed studies of representative systems within this region. In this paper we present a model artificial freshwater storage: Gold Creek Dam in South East Queensland, Australia. Freshwater storages are commonplace for drinking water and irrigation purposes in Australia as unpredictable rainfall patterns make river and ground water sources unreliable. Over 85 % of Australian rivers are modified with weirs and dams providing permanent inundation of previously terrestrial environments. The higher temperatures experienced at these latitudes drive thermal stratification of these systems as well as rapidly deoxygenate bottom waters. High organic matter availability in the sediment zone as well as the anoxic overlying water provide ideal conditions for reduced products (including methane and ammonia) from microbial processing to be formed and diffuse into bottom waters. A mid-water metalimnion is generally associated with large gradients in dissolved oxygen availability and reduced metabolites undergo oxidation prior to their emission from water surface. An intensive field study was undertaken to improve understanding of production and transformation rates of methane and nitrous oxide from the sediments, through the water column and to the atmosphere. Sediment nutrient (ammonia, nitrite/nitrate and filterable reactive phosphorus) and greenhouse gas (methane and nitrous oxide) porewater samples were collected at selected sites. To determine the magnitude of the benthic sediment contribution of methane and nitrous oxide to the water column sediment incubations were conducted in the

  11. Nitrous oxide production pathways in a partial nitritation-anammox reactor: Isotopic evidence for nitrous oxide production associated anaerobic ammonium oxidation?

    Science.gov (United States)

    Wunderlin, P.; Harris, E. J.; Joss, A.; Emmenegger, L.; Kipf, M.; Mohn, J.; Siegrist, H.

    2014-12-01

    Nitrous oxide (N2O) is a strong greenhouse gas and a major sink for stratospheric ozone. In biological wastewater treatment N2O can be produced via several pathways. This study investigates the dynamics of N2O emissions from a nitritation-anammox reactor, and links its interpretation to the nitrogen and oxygen isotopic signature of the emitted N2O. A 400-litre single-stage nitritation-anammox reactor was operated and continuously fed with digester liquid. The isotopic composition of N2O emissions was monitored online with quantum cascade laser absorption spectroscopy (QCLAS; Aerodyne Research, Inc.; Waechter et al., 2008). Dissolved ammonium and nitrate were monitored online (ISEmax, Endress + Hauser), while nitrite was measured with test strips (Nitrite-test 0-24mgN/l, Merck). Table 1. Summary of experiments conducted to understand N2O emissions Experimental conditions O2[mgO2/L] NO2-[mgN/L] NH4+[mgN/L] N2O/NH4+[%] Normal operation reactor. Our data reveal that N2O emissions increased when reactor operation was not ideal, for example when dissolved oxygen was too high (Table 1). SP measurements confirmed that these N2O peaks were due to enhanced nitrifier denitrification, generally related to nitrite build-up in the reactor (Figure 1; Table 1). Overall, process control via online N2O monitoring was confirmed to be an ideal method to detect imbalances in reactor operation and regulate aeration, to ensure optimal reactor conditions and minimise N2O emissions. ReferencesWaechter H. et al. (2008) Optics Express, 16: 9239-9244. Wunderlin, P et al. (2013) Environmental Science & Technology 47: 1339-1348.

  12. Biochemical characterization of the purple form of Marinobacter hydrocarbonoclasticus nitrous oxide reductase

    Science.gov (United States)

    Dell'Acqua, Simone; Pauleta, Sofia R.; Moura, José J. G.; Moura, Isabel

    2012-01-01

    Nitrous oxide reductase (N2OR) catalyses the final step of the denitrification pathway—the reduction of nitrous oxide to nitrogen. The catalytic centre (CuZ) is a unique tetranuclear copper centre bridged by inorganic sulphur in a tetrahedron arrangement that can have different oxidation states. Previously, Marinobacter hydrocarbonoclasticus N2OR was isolated with the CuZ centre as CuZ*, in the [1Cu2+ : 3Cu+] redox state, which is redox inert and requires prolonged incubation under reductive conditions to be activated. In this work, we report, for the first time, the isolation of N2OR from M. hydrocarbonoclasticus in the ‘purple’ form, in which the CuZ centre is in the oxidized [2Cu2+ : 2Cu+] redox state and is redox active. This form of the enzyme was isolated in the presence of oxygen from a microaerobic culture in the presence of nitrate and also from a strictly anaerobic culture. The purple form of the enzyme was biochemically characterized and was shown to be a redox active species, although it is still catalytically non-competent, as its specific activity is lower than that of the activated fully reduced enzyme and comparable with that of the enzyme with the CuZ centre in either the [1Cu2+ : 3Cu+] redox state or in the redox inactive CuZ* state. PMID:22451106

  13. Nitrous oxide production from sequencing batch reactor sludge under nitrifying conditions: effect of nitrite concentrations.

    Science.gov (United States)

    Gong, Youkui; Wang, Shuying; Wang, Sai; Peng, Yongzhen

    2012-01-01

    Nitrous oxide (N2O), a greenhouse gas which contributes to the destruction of the stratospheric ozone layer, can be emitted from nitrifying processes during wastewater treatment. The pathway of N2O production was studied using a lab-scale nitrifying reactor. Allylthiourea was used to inhibit NH4+ oxidation and provide information on processes that happen under nitrifying condition. Our study confirmed that besides heterotrophic bacteria, ammonium-oxidizing bacteria could perform denitrification processes, during which NO2- was the electron acceptor and NH4+ was the electron donor, with N2 and N2O as final products. The relative contribution of the heterotrophic denitrification process to total N2O emissions varied from 46.1% to 60.4% depending on NO2(-)-N addition. Correspondingly, 21.8% to 51.5% of total N2O emissions can be attributed to nitrifier denitrification. Little N2O is emitted during the NO2- oxidation process.

  14. Ammonia and Nitrous Oxide Emissions from Broiler Houses with Downtime Windrowed Litter.

    Science.gov (United States)

    Ro, Kyoung S; Moore, Philip A; Szogi, Ariel A; Millner, Patricia D

    2017-05-01

    An emerging poultry manure management practice is in-house windrowing to disinfect the litter. However, this practice is likely to increase emissions of ammonia (NH) and nitrous oxide (NO) from the windrowed litter. The objective of this study was to quantitatively compare NH and NO emissions from broiler houses with and without in-house windrowing. Two broiler houses at a commercial farm were used to compare the NH and NO emissions. Gas emission measurements were conducted continuously and simultaneously for both the control house (without windrowing) and the house with windrowing during the same production periods. The house emission rates were calculated by multiplying the hourly mean gas concentrations and the ventilation rates. The windrowed litter temperature was significantly higher than that of the control litter. The impact of downtime (the time lapse between flocks, during which the bird house is empty) windrowing litter on pathogen reduction was inconclusive because of very low or no recovery of both and spp. from control or windrowed litter samples, respectively. The windrowing house NH emissions were 26.2 and 16.6 kg d house, whereas for the control house, they were 14.6 and 12.8 kg d house in 2012 and 2013, respectively. The NO emissions from the windrowing house were also higher than those from the control house. The total NH and NO emissions from broiler houses practicing windrowing litter management were estimated to be 35.0 and 4.43 g bird, respectively, compared with 31.9 and 3.89 g bird for the control house, respectively. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  15. Acetylene and oxygen as inhibitors of nitrous oxide production in Nitrosomonas europaea and Nitrosospira briensis: a cautionary tale

    NARCIS (Netherlands)

    Wrage, N.; Velthof, G.L.; Oenema, O.; Laanbroek, H.J.

    2004-01-01

    Autotrophic ammonia-oxidizing bacteria produce nitrous oxide (N2O) as a by-product of nitrification or as an intermediate of nitrifier denitrification. In soil incubations, acetylene (C2H2) and large partial pressures of oxygen (O-2) are used to distinguish between these sources. C2H2 inhibits

  16. Acetylene and oxygen as inhibitors of nitrous oxide production in Nitrosomonas europaea and Nitrosospira briensis: a cautionary tale

    NARCIS (Netherlands)

    Wrage, N.; Velthof, G.L.; Oenema, O.; Laanbroek, H.J.

    2004-01-01

    Autotrophic ammonia-oxidizing bacteria produce nitrous oxide (N2O) as a by-product of nitrification or as an intermediate of nitrifier denitrification. In soil incubations, acetylene (C2H2) and large partial pressures of oxygen (O2) are used to distinguish between these sources. C2H2 inhibits

  17. Acetylene and oxygen as inhibitors of nitrous oxide production in Nitrosomonas euroepaea and Nitrosospir briensis: a cautionary tale

    NARCIS (Netherlands)

    Wrage, N.; Velthof, G.L.; Oenema, O.; Laanbroek, H.J.

    2004-01-01

    Autotrophic ammonia-oxidizing bacteria produce nitrous oxide (N2O) as a by-product of nitrification or as an intermediate of nitrifier denitrification. In soil incubations, acetylene (C2H2) and large partial pressures of oxygen (O2) are used to distinguish between these sources. C2H2 inhibits

  18. Land use and land use change effects on nitrous oxide emissions in the seasonally dry ecosystems of Zimbabwe

    DEFF Research Database (Denmark)

    Nyamadzawo, G; Chirinda, Ngoni; Mapanda, F

    2012-01-01

    . The savanna woodlands cover over 95% of Zimbabwe’s forest area, and are divided into five woodland types: Acacia, miombo, mopane, teak (Baikiaea Plurijuga) and Terminalia-Combretaceae. This review is aimed at exploring the effects of land-use changes and land management practices on N2O emissions in Zimbabwe......Nitrous oxide (N2O) is a greenhouse gas (GHG) with a considerable warming potential and involvement in the destruction of stratospheric ozone. The conversion of savannas to agricultural land has the potential of changing the characteristics and gas exchange of the ecosystems dramatically....... Available data on N2O emission were collected from standing and deforested miombo woodlands, grasslands and agricultural lands. Estimated mean annual N2O emissions from savanna ecosystems in Zimbabwe were 17.1 Gg N2O, while annual fluxes from arable land (cultivated and fallow) was 3.19 Gg N2O. Biogenic N2O...

  19. Assessment of reinforcement enhancing effects of toluene vapor and nitrous oxide in intracranial self-stimulation

    Science.gov (United States)

    Tracy, Matthew E.; Slavova-Hernandez, Galina G.; Shelton, Keith L.

    2013-01-01

    Rationale Despite widespread abuse there are few validated methods to study the rewarding effects of inhalants. One model that that may have utility for this purpose is intracranial self-stimulation (ICSS). Objectives We wished to compare and contrast the ICSS reward-facilitating effects of abused inhalants to other classes of abused drugs. Compounds were examined using two different ICSS procedures in mice to determine the generality of each drug's effects on ICSS and the sensitivity of the procedures. Methods Male C57BL/6J mice with electrodes implanted in the medial forebrain bundle were trained under a three component rate-frequency as well as a progressive ratio (PR) ICSS procedure. The effects of nitrous oxide, toluene vapor, cocaine and diazepam on ICSS were then examined. Results Concentrations of 1360-2900 ppm inhaled toluene vapor significantly facilitated ICSS in the rate frequency procedure and 1360 ppm increased PR breakpoint. A concentration of 40% nitrous oxide facilitated ICSS in the rate-frequency procedure but reduced PR breakpoint. Doses of 3-18 mg/kg cocaine facilitated ICSS in the rate frequency procedure and 10 and 18 mg/kg increased PR breakpoint. Doses of 1 and 3 mg/kg diazepam facilitated ICSS in the rate frequency procedure and 3 mg/kg increased PR breakpoint. Conclusions The reinforcement facilitating effect of toluene in ICSS is at least as great as diazepam. In contrast, nitrous oxide weakly enhances ICSS in only the rate frequency procedure. The data suggest that the rate frequency procedure may be more sensitive than the PR schedule to the reward facilitating effects of abused inhalants. PMID:24186077

  20. Investigations on measures to reduce nitrous oxide (N2O); Asanka chisso (N2O) no teigen taisaku ni kansuru chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Discussions were given on measures to reduce N2O as part of the measures to prevent global warming. Nitrous oxide has a long atmospheric lifetime of 150 years, and its greenhouse warming potential will increase by 310 times that of CO2 after 100 years. It can also be a cause of ozone layer destruction. Nitrous oxide is estimated to have influence of about 10% as compared with CO2 even under the present conditions. Discharge of N2O from manufacturing process of adipic acid is aimed to be eliminated totally by 1998. Improvement in efficiency of combustion of fossil fuels and wastes serves most effectively to reduce not only N2O but also CO2. Nitrous oxide generated in sewage treatment as in sewage purifier may be reduced if the batch process is turned into a continuous process, but assistance from policy side would be required for wider adoption of the process conversion. No environmental regulations are applicable to N2O, whereas a problem is present that the number of system installation would not grow because of economic reasons even if the system is feasible technically. Another problem is that the N2O reducing technology is in trade-off relation with other warming gases such as NOx and methane. Comprehensive technological evaluations aimed at optimization must be moved forward in the future. 236 refs., 102 figs., 78 tabs.

  1. Emissions of nitrous oxide from Irish arable soils: effects of tillage and reduced N input

    DEFF Research Database (Denmark)

    Abdalla, M.; Jones, M.B.; Ambus, Per

    2010-01-01

    Nitrous oxide (N2O) flux measurements from an Irish spring barley field managed under conventional and reduced tillage and different N fertilizer applications at the Teagasc Oak Park Research Centre were made for two consecutive seasons. The aim was to investigate the efficacy of reduced tillage....... Reduced tillage had no significant effect on N2O fluxes from soils or crop grain yield. Multiple regression analysis revealed that soil moisture and an interaction between soil moisture and soil nitrate are the main significant factors affecting N2O flux. The derived emission factor was 0...

  2. Direct nitrous oxide emission from the aquacultured Pacific white shrimp (Litopenaeus vannamei)

    OpenAIRE

    Heisterkamp, Ines M; Schramm, Andreas; de Beer, Dirk; Stief, Peter

    2016-01-01

    The Pacific white shrimp (Litopenaeus vannamei) is widely used in aquaculture, where it is reared at high stocking densities, temperatures, and nutrient concentrations. Here we report that adult L. vannamei shrimp emit the greenhouse gas nitrous oxide (N2O) at an average rate of 4.3 nmol N2O/individual × h, which is 1 to 2 orders of magnitude higher than previously measured N2O emission rates for free-living aquatic invertebrates. Dissection, incubation, and inhibitor experiments with specime...

  3. Powerful greenhouse gas nitrous oxide adsorption onto intrinsic and Pd doped Single walled carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Yoosefian, Mehdi, E-mail: m.yoosefian@kgut.ac.ir

    2017-01-15

    Highlights: • Investigation of the adsorption of Nitrous oxide on SWCNT and Pd/SWCNT. • Nitrous oxide adsorbed on Pd/SWCNT system demonstrates a strong adsorption. • The Pd/SWCNT is potential sensor for the Nitrous oxide gaseous molecule detection. - Abstract: Density functional studies on the adsorption behavior of nitrous oxide (N{sub 2}O) onto intrinsic carbon nanotube (CNT) and Pd-doped (5,5) single-walled carbon nanotube (Pd-CNT) have been reported. Introduction of Pd dopant facilitates in adsorption of N{sub 2}O on the otherwise inert nanotube as observed from the adsorption energies and global reactivity descriptor values. Among three adsorption features of N{sub 2}O onto CNT, the horizontal adsorption with E{sub ads} = −0.16 eV exhibits higher adsorption energy. On the other hand the Pd-CNT exhibit strong affinity toward gas molecule and would cause a huge increase in N{sub 2}O adsorption energies. Chemical and electronic properties of CNT and Pd-CNT in the absence and presence of N{sub 2}O were investigated. Adsorption of N{sub 2}O gas molecule would affect the electronic conductance of Pd-CNT that can serve as a signal of gas sensors and the increased energy gaps demonstrate the formation of more stable systems. The atoms in molecules (AIM) theory and the natural bond orbital (NBO) calculations were performed to get more details about the nature and charge transfers in intermolecular interactions within adsorption process. As a final point, the density of states (DOSs) calculations was achieved to confirm previous results. According to our results, intrinsic CNT cannot act as a suitable adsorbent while Pd-CNT can be introduced as novel detectable complex for designing high sensitive, fast response and high efficient carbon nanotube based gas sensor to detect N{sub 2}O gas as an air pollutant. Our results could provide helpful information for the design and fabrication of the N{sub 2}O sensors.

  4. The synthesis and exchange chemistry of frustrated Lewis pair–nitrous oxide complexes

    NARCIS (Netherlands)

    Neu, Rebecca C.; Otten, Edwin; Lough, Alan; Stephan, Douglas W.

    2011-01-01

    Facile activation of nitrous oxide is achieved using a series of fluoroarylboranes, B(C6F5)3, PhB(C6F5)2, MesB(C6F5)2, (C6F5)2BOC6F5, B(C6F4-p-H)3, B(C6H4-p-F)3 and 1,4-(C6F5)2BC6F4B(C6F5)2 in the presence of the basic, bulky phosphine tBu3P. Room temperature reaction yields mono- and

  5. Clinical experience with TENS and TENS combined with nitrous oxide-oxygen. Report of 371 patients.

    OpenAIRE

    Quarnstrom, F. C.; Milgrom, P.

    1989-01-01

    Transcutaneous electrical nerve stimulation (TENS) alone or TENS combined with nitrous oxide-oxygen (N2O) was administered for restorative dentistry without local anesthesia to 371 adult patients. A total of 55% of TENS alone and 84% of TENS/N2O visits were rated successful. A total of 53% of TENS alone and 82% of TENS/N2O patients reported slight or no pain. In multivariable analyses, pain reports were related to the anesthesia technique and patient fear and unrelated to sex, race, age, toot...

  6. Bispectral EEG index monitoring of high-dose nitrous oxide and low-dose sevoflurane sedation.

    OpenAIRE

    Hall, David L; Weaver, Joel; Ganzberg, Steven; Rashid, Robert; Wilson, Stephen

    2002-01-01

    This single-blind controlled clinical study characterized the effects of 30-70% nitrous oxide (N2O) and 0.2-0.8% sevoflurane conscious sedation on quantitative electroencephalographic (EEG) readings of 22 healthy dental students as measured by the bispectral index (BIS). The study verified the 2 previously published BIS/N2O investigations showing no correlation between N2O dosage up to 70% and BIS. Observer's Assessment of Alertness and Sedation scores (OAA/S), however, correlated well with i...

  7. Dynamic modelling of nitrous oxide emissions from three Swedish sludge liquor treatment systems

    DEFF Research Database (Denmark)

    Lindblom, E.; Arnell, M.; Flores-Alsina, X.

    2014-01-01

    The objective of this paper is to model the dynamics and validate the results of nitrous oxide (N2O)emissions from three Swedish nitrifying/denitrifying, nitritation and anammox systems treating real anaerobic digester sludge liquor. The Activated Sludge Model No. 1 is extended to describe N2O...... production by both heterotrophic and autotrophic denitrification. In addition, mass transfer equations are implemented to characterize the dynamics of N2O in the water and the gas phases.The biochemical model is simulated and validated for two hydraulic patterns: (1) a sequencing batch reactor; and, (2...

  8. Nitrous oxide emission budgets and land-use-driven hotspots for organic soils in Europe

    DEFF Research Database (Denmark)

    Leppelt, T; Dechow, R; Gebbert, S

    2014-01-01

    relating the upscaling process to a priori-identified key drivers by using available N2O observations from plot scale in empirical approaches. We used the empirical fuzzy modelling approach MODE to identify main drivers for N2O and utilize them to predict the spatial emission pattern of European organic......Organic soils are a main source of direct emissions of nitrous oxide (N2O), an important greenhouse gas (GHG). Observed N2O emissions from organic soils are highly variable in space and time, which causes high uncertainties in national emission inventories. Those uncertainties could be reduced when...

  9. Proposed reference models for nitrous oxide and methane in the middle atmosphere

    Science.gov (United States)

    Taylor, F. W.; Dudhia, A.; Rodgers, C. D.

    1989-01-01

    Data from the Stratospheric and Mesospheric Sounder (SAMS) on the Nimbus 7 satellite, for the period from Jan. 1979 - Dec. 1981, are used to prepare a reference model for the long-lived trace gases, methane and nitrous oxide, in the stratosphere. The model is presented in tabular form on seventeen pressure surfaces from 20 to 0.1 mb, in 10 degree latitude bins from 50S to 70N, and for each month of the year. The means by which the data quality and interannual variability, and some of the more interesting globally and seasonally variable features of the data are discussed briefly.

  10. Spatial and temporal variability of nitrous oxide emissions in a mixed farming landscape of Denmark

    DEFF Research Database (Denmark)

    Schelde, Kirsten; Cellier, P; Bertolini, T

    2012-01-01

    Nitrous oxide (N2O) emissions from agricultural land are variable at the landscape scale due to variability in land use, management, soil type, and topography. A field experiment was carried out in a typical mixed farming landscape in Denmark, to investigate the main drivers of variations in N2O...... emissions during spring 2009 were relatively low, with maximum values below 20 ng N m−2 s−1. This applied to all land use types including winter grain crops, grasslands, meadows, and wetlands. Slurry application to wheat fields resulted in short-lived two-fold increases in emissions. The moderate N2O fluxes...

  11. Methoxyflurane and Nitrous Oxide as Obstetric Analgesics. II.—A Comparison by Self-administered Intermittent Inhalation

    Science.gov (United States)

    Jones, Peter L.; Rosen, M.; Mushin, W. W.; Jones, E. V.

    1969-01-01

    Methoxyflurane (0·35%) in air and nitrous oxide/oxygen (50%/50%) self-administered intermittently in the usual way have been compared as analgesics for labour. There were 25 patients in each group. Objective assessment by an anaesthetist showed that methoxyflurane is the more effective analgesic, and this was supported by the opinion of the multiparae. Nausea and vomiting were significantly less with methoxyflurane. Fifty per cent. nitrous oxide in oxygen given intermittently does not appear to be the best analgesic concentration. Nevertheless, since a considerable variation in sensitivity exists, it would probably be unwise to consider the introduction of higher concentrations for use by unsupervised midwives. This trial confirms the predictions made by us using a method for screening inhalational analgesics, in which methoxyflurane and nitrous oxide were given continuously. PMID:4895339

  12. Peripheral Neuropathy Due to Recreational Use of Nitrous Oxide Presenting After an Ankle Sprain With Foot Drop.

    Science.gov (United States)

    Middleton, Jackson A; Roffers, John A

    2017-11-08

    A 22-year-old man was referred for orthopedic follow-up after an ankle injury. Initial evaluation in urgent care included radiographs with negative findings. After a delayed presentation, a course of functional treatment was recommended. Subsequently, he developed a deep venous thrombosis and pulmonary emboli. He was found to be factor V Leiden deficient and was fully anticoagulated on warfarin. Later reevaluation revealed a steppage gait and foot drop. Electrodiagnostic studies (ie, electromyography and nerve conduction studies) revealed a severe peripheral polyneuropathy. The patient admitted to engaging in high-volume recreational use of nitrous oxide. Neurological evaluation confirmed vitamin B12 deficiency consistent with the toxic effects of nitrous oxide. The patient's condition improved with vitamin B supplementation, bracing, and avoidance of nitrous oxide and similar neurotoxins. He participated in a 3-month physical rehabilitation program, and he displayed partial recovery at most recent follow-up. [Orthopedics. 201x; xx(x):xx-xx.]. Copyright 2017, SLACK Incorporated.

  13. [The effects of hyperventilation upon spinal dorsal horn neuronal single-unit activities under nitrous oxide anesthesia].

    Science.gov (United States)

    Ide, Yasuo; Tagami, Megumu; Sumida, Toshinobu; Hanaoka, Kazuo

    2005-07-01

    The purpose of this study is to investigate the effects of hyperventilation upon spinal dorsal horn neuronal single-unit activities under nitrous oxide anesthesia. Eight decerebrated spinal cats with laminectomy were maintained with oxygen and pancuronium bromide. Following the control period of normocapnia, 50% nitrous oxide was administered for 30 minutes after a hypocapnia period of 20-25 mmHg for 20 minutes. The recoveries of activities followed with normocapnia and pure oxygen administration. The changes of spontaneous and evoked activities by the pinching were investigated every 5 minutes after control study. Inhalation of 50% nitrous oxide suppressed the WDR neuronal activities and with hyperventilation the suppressions significantly increased. These results were compatible with clinical reports on the effectiveness of hyperventilation as a maintenance method under N2O anesthesia.

  14. Nitrogen retention, removal, and nitrous oxide production in the Elbe Estuary

    Science.gov (United States)

    Dähnke, Kirstin; Brase, Lisa; Jacob, Juliane; Sanders, Tina

    2017-04-01

    The Elbe River, an important tributary to the coastal North Sea, is subject to massive anthropogenic pressures from, for example, fertilization and dredging of the river and its estuary. Despite clear improvements in nutrient loads, we find that these changes have impacted the river's capacity to cope with surplus inputs of nutrients. Based on measurements of nitrate stable isotopes and N2O concentration profiles, we investigated the estuarine capacity of nitrogen retention and denitrification, and compared it to the situation several decades ago. A combined water-column and sediment-based approach suggests that the denitrification capacity has decreased significantly to no more than 5-10% of summer nitrate loads, while nitrate regeneration via nitrification has in turn gained in importance. Active biogeochemical nitrogen cycling, seems to be almost exclusively restricted to the deeper areas of the port of Hamburg, where deepening of the riverbed has led to immense recycling activity. Overall, we find that the remineralization and oxidation of organic matter dominates the riverine N-budget. This is apparent in stable isotope signatures in the estuary and the limnic water sections, for which we calculated relative ratios of denitrification and nitrification. This shift from denitrification to nitrification is also mirrored in the production of nitrous oxide, which, despite improved nutrient status of the river and estuary, remained high. In combination, our data suggest that high loads of dissolved inorganic nitrogen and nitrous oxide production are a legacy of the past eutrophication period, and of enhanced upstream primary production.

  15. Fluxes of nitrous oxide and carbon dioxide over four potential biofuel crops in Central Illinois

    Science.gov (United States)

    Zeri, M.; Hickman, G. C.; Bernacchi, C.

    2009-12-01

    -Obukhov stability parameter L. The last two variables are provided by eddy covariance systems in each field. Preliminary results show a good agreement between CO2 fluxes derived from the flux-gradient and eddy covariance methods for daytime conditions. This agreement is a good validation of the calculations and confirms that the N2O fluxes are being correctly estimated. The two methods disagree during nighttime due to the underestimation of eddy covariance fluxes for non-turbulent conditions. The fluxes of nitrous oxide at the corn plot were stronger and responded faster to precipitation. The highest fluxes were observed during the second half of June 2009 after a series of rain events. The highest emission at this time occurred for corn, followed by Miscanthus (half of what was observed for corn). Prairie and switchgrass presented half and a quarter, respectively, of what was observed for miscanthus.

  16. Flood effects on efflux and net production of nitrous oxide in river floodplain soils

    Science.gov (United States)

    Riaz, Muhammad; Bruderer, Christian; Niklaus, Pascal A.; Luster, Jörg

    2016-04-01

    Floodplain soils are often rich in nutrients and exhibit high spatial heterogeneity in terms of geomorphology, soil environmental conditions and substrate availability for processes involved in carbon and nutrient cycling. In addition, fluctuating water tables lead to temporally changing redox conditions. In such systems, there are ideal conditions for the occurrence of hot spots and moments of nitrous oxide emissions, a potent greenhouse gas. The factors that govern the spatial heterogeneity and dynamics of N2O formation in floodplain soils and the surface efflux of this gas are not fully understood. A particular issue is the contribution of N2O formation in the subsoil to surface efflux. We studied this question in the floodplain of a restored section of the Thur river (NE Switzerland) which is characterized by a flashy flow regime. As a consequence, the floodplain soils are unsaturated most of the time. We showed earlier that saturation during flood pulses leads to short phases of generally anoxic conditions followed by a drying phase with anoxic conditions within aggregates and oxic conditions in larger soil pores. The latter conditions are conducive for spatially closely-coupled nitrification-denitrification and related hot moments of nitrous oxide formation. In a floodplain zone characterized by about one meter of young, sandy sediments, that are mostly covered by the tall grass Phalaris arundinacea, we measured at several time points before and after a small flood event N2O surface efflux with the closed-chamber method, and assessed N2O concentrations in the soil air at four different depths using gas-permeable tubings. In addition, we calculated the N2O diffusivity in the soil from Radon diffusivity. The latter was estimated in-situ from the recovery of Radon concentration in the gas-permeable tubings after purging with ambient air. All these data were then used to calculate net N2O production rates at different soil depths with the gradient method. In

  17. Environmental and microbial factors influencing methane and nitrous oxide fluxes in Mediterranean cork oak woodlands: trees make a difference

    Directory of Open Access Journals (Sweden)

    Alla eShvaleva

    2015-10-01

    Full Text Available Cork oak woodlands (montado are agroforestry systems distributed all over the Mediterranean basin with a very important social, economic and ecological value. A generalized cork oak decline has been occurring in the last decades jeopardizing its future sustainability. It is unknown how loss of tree cover affects microbial processes that are consuming greenhouse gas fluxes in the montado ecosystem. The study was conducted under two different conditions in the natural understory of a cork oak woodland in center Portugal: under tree canopy (UC and open areas without trees (OA. Fluxes of methane and nitrous oxide were measured with a static chamber technique. In order to quantify methanotrophs and bacteria capable of nitrous oxide consumption, we used quantitative real-time PCR targeting the pmoA and nosZ gene encoding the subunit of particulate methane mono-oxygenase and catalytic subunit of the nitrous oxide reductase, respectively. A significant seasonal effect was found on CH4 and N2O fluxes and pmoA and nosZ gene abundance. Tree cover had no effect on methane fluxes; conversely, whereas the UC plots were net emitters of nitrous oxide, the loss of tree cover resulted in a shift in the emission pattern such that the OA plots were a net sink for nitrous oxide. In a seasonal time scale, the UC had higher gene abundance of Type I methanotrophs. Methane flux correlated negatively with abundance of Type I methanotrophs in the UC plots. Nitrous oxide flux correlated negatively with nosZ gene abundance at the OA plots in contrast to that at the UC plots. In the UC soil, SOM had a positive effect on soil extracellular enzyme activities (EEA, which correlated positively with the N2O flux. Our results demonstrated that tree cover affects soil properties, key enzyme activities and abundance of microorganisms and, consequently net CH4 and N2O exchange.

  18. Effect of nitrous oxide on folate coenzyme distribution and de novo synthesis of thymidylate in human bone marrow cells

    OpenAIRE

    Ermens, Anton; Schoester, Martijn; Lindemans, Jan; Abels, J.

    1992-01-01

    markdownabstractAbstract The effect of nitrous oxide on intracellular folate metabolism of the human bone marrow was studied in vitro. Bone marrow cells, obtained from healthy volunteers, were incubated with 5 × 10−8m-[3H]5-formyltetrahydrofolate (5-formylTHF) for 18 hr to label intracellular folate pools. Subsequently the cells were exposed to nitrous oxide for up to 10 hr, and the intracellular folate coenzyme levels were quantitated by HPLC. The dU suppression test was carried out on part ...

  19. Effect of Nitrous Oxide Anaesthesia on Endotracheal Cuff Pressure

    Directory of Open Access Journals (Sweden)

    Özlem Koşar

    2017-03-01

    Full Text Available Aim: When N2Ois used for general anaesthesia, it diffuses into the air-filled endotracheal cuff causing the cuff pressure to rise by over inflating the cuff, which results in tracheal damage. This study aimed to estimate changes in the endotracheal-cuff pressure with time during oxygen-air- and oxygen-N2O -induced anaesthesia and to determine its sore throat and hoarseness incidence. Methods: Fifty patients with American Society of Anesthesiologists physical status 1-2, aged 18-60 years were icluded to our study. Orotracheal intubation was performed using polyvinyl chloride high volume-low pressure endotracheal tubes. The AIR group 40% O2/60% air and N2O group 40% O2/60% N2O was used. The endotracheal cuff pressure at 5, 10, 15, 20 minutes immediately after intubation and at 10-minute intervals were recorded. When the cuff pressure reached 45 cm H2O, was attenuated to 25-30-cm H2O. At the post operative first and the 24th hour, the patients were queried for sore throat and hoarseness. Results: The N2O -group cuff pressure rose from the fifth minute onwards. Also, the N2O group had a higher incidence of sore throat and hoarseness. Conclusion: N2O results in elevated cuff pressure and tracheal morbidities. Cuff-pressure should be routinely monitored during anaesthesia using N2O.

  20. Biologically-associated Nitrous Oxide Accumulation in the Euphotic Zone

    Science.gov (United States)

    Xianhui, W. S.

    2016-02-01

    The largest uncertainty and inconsistency in global marine N2O emission estimate appear in the euphotic zone, where light and phytoplankton competition inhibit nitrification, a major contributor to N2O production. The rigorous physical disturbance in the surface ocean prevents the N2O accumulation thus potentially masking the role of biological N2O production. Here we presented high vertical resolution N2O profiles in the euphotic zone from the oligotrophic South China Sea and mid-latitude northwestern Pacific Ocean. Distinctive N2O peaks, which deviated from the vertical mixing curve, were observed near the nitracline, of which the maximum of Chl-a and nitrite appeared correspondingly. The intimate association between N2O excursion and biological parameters suggests that extra source in the euphotic zone is required to support such N2O offset. By using 15NH4+ and 15NO2- tracers, we measured rates and explored the potential processes associated with N2O production. More high vertical resolution observation and process studies are urgently needed to explore the spatial-temporal distribution of euphotic zone N2O production and its controlling mechanisms to fill the knowledge gap. In addition, innovative methods are required to discern pathways biologically produced N2O in mixed layer from physical supply from deeper ocean.

  1. Nitrous oxide uptake rates in boreal coniferous forests are associated with soil characteristics

    Science.gov (United States)

    Siljanen, Henri; Biasi, Christina; Martikainen, Pertti

    2014-05-01

    Nitrous oxide (N2O) is a strong greenhouse gas and a significant contributor to the destruction of the ozone layer. The radiative forcing of N2O is considered to be 320 more efficient than carbon dioxide.The major portion of global N2O is emitted from agricultural soils. There are studies suggesting that N2O has also a sink in forest soils. However there is relatively limited knowledge on factors controlling N2O consumption in forest soils. Hence N2O consumption was studied in boreal coniferous forests having different forest cover, soil chemical and physical structure and land-use history. The N2O consumption was measured by static chamber technique in the field across spatio-seasonal sampling design. Typical and atypical denitrifiers were quantified with nosZ functional gene marker. Additionally chemical and physical environmental parameters were analyzed to link N2O flux, microbial community and composition of soils. Nitrous oxide uptake could be associated with specific ecosystem and environmental conditions. Soil physical structure and land-use history were shown to be prior factors determining the strength of the uptake rate.

  2. Survey of American Academy of Pediatric Dentistry on Nitrous Oxide and Sedation: 20 Years Later.

    Science.gov (United States)

    Wilson, Stephen; Gosnell, Elizabeth S

    2016-10-15

    The purpose of this study was to survey the membership of the American Academy of Pediatric Dentistry (AAPD) and determine the current status of nitrous oxide (N2O) utilization in their dental practices while also comparing the findings to a similar survey completed 20 years ago. A 55-item questionnaire on the use of N2O was sent to the AAPD membership. The total number of respondents was 1,632 (26 percent). Sixty-two percent are board-certified, 97 percent use N2O in their office, 18 percent indicated greater than 80 percent of their patient pool required N2O versus six percent in 1996. Fifty percent of parents expressed concerns about N2O use. Changes have occurred in the use of nitrous oxide since 1996, including: (1) a greater percentage of practitioners using N2O; (2) perceptions that more pediatric patients need N2O; (3) a shift in use of N2O by duration of practitioner experience; (4) an increased percentage of board-certified respondents; and (5) possible increasing parental concerns about N2O.

  3. Do lagoons near concentrated animal feeding operations promote nitrous oxide supersaturation?

    Energy Technology Data Exchange (ETDEWEB)

    Makris, Konstantinos C., E-mail: kcmakris@gmail.co [Cyprus International Institute for the Environment and Public Health in association with the Harvard School of Public Health, 5 Iroon Street, 1105 Nicosia (Cyprus); Sarkar, Dibyendu [Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ (United States); Andra, Syam S. [Environmental Geochemistry Laboratory, University of Texas at San Antonio, San Antonio, TX (United States); Bach, Stephan B.H. [Department of Chemistry, University of Texas at San Antonio, San Antonio, TX (United States); Datta, Rupali [Department of Biology, Michigan Technological University, Houghton, MI (United States)

    2009-06-15

    Animal wastewater lagoons nearby concentrated animal feeding operations (CAFOs) represent the latest tendency in global animal farming, severely impacting the magnitude of greenhouse gas emissions, including nitrous oxide (N{sub 2}O). We hypothesized that lagoon wastewater could be supersaturated with N{sub 2}O as part of incomplete microbial nitrification/denitrification processes, thereby regulating the N{sub 2}O partitioning in the gaseous phase. The objectives of this study were: (i) to investigate the magnitude of dissolved N{sub 2}O concentrations in the lagoon; and (ii) to determine the extent to which supersaturation of N{sub 2}O occurs in wastewater lagoons. Dissolved N{sub 2}O concentrations in the wastewater samples were high, ranging from 0.4 to 40.5 mug N{sub 2}O mL{sup -1}. Calculated dissolved N{sub 2}O concentrations from the experimentally measured partition coefficients were much greater than those typically expected in aquatic systems (nitrous oxide may occur in lagoons near concentrated animal feeding operations.

  4. Biological sources and sinks of nitrous oxide and strategies to mitigate emissions

    Science.gov (United States)

    Thomson, Andrew J.; Giannopoulos, Georgios; Pretty, Jules; Baggs, Elizabeth M.; Richardson, David J.

    2012-01-01

    Nitrous oxide (N2O) is a powerful atmospheric greenhouse gas and cause of ozone layer depletion. Global emissions continue to rise. More than two-thirds of these emissions arise from bacterial and fungal denitrification and nitrification processes in soils, largely as a result of the application of nitrogenous fertilizers. This article summarizes the outcomes of an interdisciplinary meeting, ‘Nitrous oxide (N2O) the forgotten greenhouse gas’, held at the Kavli Royal Society International Centre, from 23 to 24 May 2011. It provides an introduction and background to the nature of the problem, and summarizes the conclusions reached regarding the biological sources and sinks of N2O in oceans, soils and wastewaters, and discusses the genetic regulation and molecular details of the enzymes responsible. Techniques for providing global and local N2O budgets are discussed. The findings of the meeting are drawn together in a review of strategies for mitigating N2O emissions, under three headings, namely: (i) managing soil chemistry and microbiology, (ii) engineering crop plants to fix nitrogen, and (iii) sustainable agricultural intensification. PMID:22451101

  5. Ammonia, nitrous oxide and hydrogen cyanide emissions from five passenger vehicles.

    Science.gov (United States)

    Karlsson, Hua Lu

    2004-12-01

    In this paper, three unregulated components, ammonia, nitrous oxide and hydrogen cyanide, emitted from five passenger vehicles are investigated. With focus upon emission factors from existing production technology, vehicles produced between 1989 and 1998 with considerable mileage (7000 to 280,000) are chosen. Among the five vehicles, four were sold in the European market, whereas one was sold in the US market. The vehicles are tested on a chassis dynamometer. An EU2000 Driving Cycle (NEDC) and a US Urban Driving Cycle (UDC) of the Federal Test Procedure 75 (FTP-75) are used in the study. The regulated emissions are measured using a Horiba Mexa series. Unregulated emissions, ammonia (NH(3)), nitrous oxide (N(2)O) and hydrogen cyanide (HCN) are analysed by mass spectrometer, gas chromatography and CNT-NA, TIM315-74W method, respectively. Both the unregulated emissions and the regulated emissions show driving cycle dependency; and they are also improved with newer vehicle and emission control technology. However, a gasoline direct injection vehicle (relatively new technology in this study) has rather high regulated emissions, whereas the NH(3), N(2)O and HCN emissions are low.

  6. Nitrogen source effects on soil nitrous oxide emissions from strip-till corn.

    Science.gov (United States)

    Halvorson, Ardell D; Del Grosso, Stephen J; Jantalia, Claudia Pozzi

    2011-01-01

    Nitrogen (N) application to crops generally results in increased nitrous oxide (NO) emissions. Commercially available, enhanced-efficiency N fertilizers were evaluated for their potential to reduce NO emissions from a clay loam soil compared with conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated strip-till (ST) corn ( L.) production system. Enhanced-efficiency N fertilizers evaluated were a controlled-release, polymer-coated urea (ESN), stabilized urea, and UAN products containing nitrification and urease inhibitors (SuperU and UAN+AgrotainPlus), and UAN containing a slow-release N source (Nfusion). Each N source was surface-band applied (202 kg N ha) at corn emergence and watered into the soil the next day. A subsurface-band ESN treatment was included. Nitrous oxide fluxes were measured during two growing seasons using static, vented chambers and a gas chromatograph analyzer. All N sources had significantly lower growing season NO emissions than granular urea, with UAN+AgrotainPlus and UAN+Nfusion having lower emissions than UAN. Similar trends were observed when expressing NO emissions on a grain yield and N uptake basis. Loss of NO-N per kilogram of N applied was fertilizer source can be a mitigation practice for reducing NO emissions in strip-till, irrigated corn in semiarid areas. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  7. Experimental testing of a liquid bipropellant rocket engine using nitrous oxide and ethanol diluted with water

    Science.gov (United States)

    Phillip, Jeff; Morales, Rudy; Youngblood, Stewart; Saul, W. Venner; Grubelich, Mark; Hargather, Michael

    2016-11-01

    A research scale liquid bipropellant rocket engine testing facility was constructed at New Mexico Tech to perform research with various propellants. The facility uses a modular engine design that allows for variation of nozzle geometry and injector configurations. Initial testing focused on pure nitrous oxide and ethanol propellants, operating in the range of 5.5-6.9 MPa (800-1000 psi) chamber pressure with approximately 667 N (150 lbf) thrust. The system is instrumented with sensors for temperature, pressure, and thrust. Experimentally found values for specific impulse are in the range of 250-260 s which match computational predictions. Exhaust flow visualization is performed using high speed schlieren imaging. The engine startup and steady state exhaust flow features are studied through these videos. Computational and experimental data are presented for a study of dilution of the ethanol-nitrous oxide propellants with water. The study has shown a significant drop in chamber temperature compared to a small drop in specific impulse with increasing water dilution.

  8. Effect of biochar on nitrous oxide emission and its potential mechanisms.

    Science.gov (United States)

    Liu, Liang; Shen, Guoqing; Sun, Mingxing; Cao, Xinde; Shang, Guofeng; Chen, Ping

    2014-08-01

    Extensive use of biochar to mitigate nitrous oxide (N2O) emission is limited by the lack of understanding on the exact mechanisms altering N2O emission from biochar-amended soil. Biochars produced from rice straw and dairy manure at 350 and 500 degrees C by oxygen-limited pyrolysis were used to investigate their influence on N2O emission. A quadratic effect of biochar levels was observed on the N2O emissions. The potential mechanisms were explored by terminal restriction fragment length polymorphism (T-RFLP) and real-time polymerase chain reaction (qPCR). A lower relative abundance of bacteria, which included ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), was observed at 4% biochar application rate. Reduced copy numbers of the ammonia monooxygenase gene amoA and the nitrite reductase gene nirS coincided with decreased N2O emissions. Therefore, biochar may potentially alter N2O emission by affecting ammonia-oxidizing and denitrification bacteria, which is determined by the application rate of biochar in soil. Implications: Biochar research has received increased interest in recent years because of the potential beneficial effects of biochar on soil properties. Recent research shows that biochar can alter the rates of nitrogen cycling in soil systems by influencing nitrification and denitrification, which are key sources of the greenhouse gas nitrous oxide (N2O). However, there are still some controversial data. The purpose of this research was to (1) examine how applications of different dose of biochar to soil affect emission of N2O and (2) improve the understanding of the underlying mechanisms.

  9. Quantifying methane and nitrous oxide emissions from the UK using a dense monitoring network

    Science.gov (United States)

    Ganesan, A. L.; Manning, A. J.; Grant, A.; Young, D.; Oram, D. E.; Sturges, W. T.; Moncrieff, J. B.; O'Doherty, S.

    2015-01-01

    The UK is one of several countries around the world that has enacted legislation to reduce its greenhouse gas emissions. Monitoring of emissions has been done through a detailed sectoral level bottom-up inventory (UK National Atmospheric Emissions Inventory, NAEI) from which national totals are submitted yearly to the United Framework Convention on Climate Change. In parallel, the UK government has funded four atmospheric monitoring stations to infer emissions through top-down methods that assimilate atmospheric observations. In this study, we present top-down emissions of methane (CH4) and nitrous oxide (N2O) for the UK and Ireland over the period August 2012 to August 2014. We used a hierarchical Bayesian inverse framework to infer fluxes as well as a set of covariance parameters that describe uncertainties in the system. We inferred average UK emissions of 2.08 (1.72-2.47) Tg yr-1 CH4 and 0.105 (0.087-0.127) Tg yr-1 N2O and found our derived estimates to be generally lower than the inventory. We used sectoral distributions from the NAEI to determine whether these discrepancies can be attributed to specific source sectors. Because of the distinct distributions of the two dominant CH4 emissions sectors in the UK, agriculture and waste, we found that the inventory may be overestimated in agricultural CH4 emissions. We also found that N2O fertilizer emissions from the NAEI may be overestimated and we derived a significant seasonal cycle in emissions. This seasonality is likely due to seasonality in fertilizer application and in environmental drivers such as temperature and rainfall, which are not reflected in the annual resolution inventory. Through the hierarchical Bayesian inverse framework, we quantified uncertainty covariance parameters and emphasized their importance for high-resolution emissions estimation. We inferred average model errors of approximately 20 and 0.4 ppb and correlation timescales of 1.0 (0.72-1.43) and 2.6 (1.9-3.9) days for CH4 and N2O

  10. Aeration strategies to mitigate nitrous oxide emissions from single-stage nitritation/anammox reactors.

    Science.gov (United States)

    Domingo-Félez, Carlos; Mutlu, A Gizem; Jensen, Marlene M; Smets, Barth F

    2014-01-01

    Autotrophic nitrogen removal is regarded as a resource efficient process to manage nitrogen-rich residual streams. However, nitrous oxide emissions of these processes are poorly documented and strategies to mitigate emissions unknown. In this study, two sequencing batch reactors performing single-stage nitritation/anammox were operated under different aeration strategies, gradually adjusted over six months. At constant but limiting oxygen loading, synthetic reject water was fed (0.75 g-N/L · d) and high nitrogen removal efficiencies (83 ± 5 and 88 ± 2%) obtained. Dynamics of liquid phase nitrous (N2O) and nitric oxide (NO) concentrations were monitored and N2O emissions calculated. Significant decreases in N2O emissions were obtained when the frequency of aeration was increased while maintaining a constant air flow rate (from >6 to 1.7% ΔN2O/ΔTN). However, no significant effect on the emissions was noted when the duration of aeration was increased while decreasing air flow rate (10.9 ± 3.2% ΔN2O/ΔTN). The extant ammonium oxidation activity (mgNH4(+)-N/gVSS · min) positively correlated with the specific N2O production rate (mgN2O-N/gVSS · min) of the systems. Operating under conditions where anaerobic exceeds aerobic ammonium oxidation activity is proposed to minimize N2O emissions from single-stage nitritation/anammox reactors; increasing the frequency of aeration cycling is an efficient way of obtaining those conditions.

  11. MLS/Aura Near-Real-Time L2 Nitrous Oxide (N2O) Mixing Ratio V003

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2N2O_NRT is the EOS Aura Microwave Limb Sounder (MLS) Near-Real-Time (NRT) product for nitrous oxide (N2O). This product contains daily N2O profiles taken from the...

  12. Update of emission factors for nitrous oxide from agricultural soils on the basis of measurements in the Netherlands

    NARCIS (Netherlands)

    Kuikman, P.J.; Hoek, van der K.W.; Smit, A.; Zwart, K.B.

    2006-01-01

    Emissions of nitrous oxide (N2O) in the Netherlands are reported to the UNFCCC on the basis of a country specific methodology. In this study we have identified and analysed the values for emission factors in measurement from in the Netherlands in the period 1993 – 2003. The overall averaged emission

  13. Comparing the effects of cryotherapy with nitrous oxide gas versus topical corticosteroids in the treatment of oral lichen planus

    Directory of Open Access Journals (Sweden)

    Dariush Amanat

    2014-01-01

    Conclusion: Cryotherapy with nitrous oxide gas is as effective as topical triamcinolone acetonide in the treatment of OLP with no systemic side effects and needs less patient compliance. It can be considered as an alternative or adjuvant therapy in OLP patients to reduce the use of treatments with adverse effects.

  14. Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

    Science.gov (United States)

    Debasish Saha; Benjamin M. Rau; Jason P. Kaye; Felipe Montes; Paul R. Adler; Armen R. Kemanian

    2016-01-01

    Future liquid fuel demand from renewable sources may, in part, be met by converting the seasonally wet portions of the landscape currently managed for soil and water conservation to perennial energy crops. However, this shift may increase nitrous oxide (N2O) emissions, thus limiting the carbon (C) benefits of energy crops. Particularly high emissions may occur during...

  15. Short-term nitrous oxide profile dynamics and emissions response to water, nitrogen and carbon additions in two tropical soils

    Science.gov (United States)

    A. D. Nobre; M. Keller; P. M. Crill; R. C. Harriss

    2001-01-01

    Tropical soils are potentially the highest and least studied nitrous oxide (N2O) production areas in the world. The effect of water, nitrate and glucose additions on profile concentrations and episodic emissions of N2O for two volcanic soils in Costa Rica was examined. Magnitudes of episodic N2O pulses, as well as overall N2O emissions, varied considerably and...

  16. Short exposure to acetylene to distinguish between nitrifier and denitrifier nitrous oxide production in soil and sediment samples

    NARCIS (Netherlands)

    Kester, R.A.; Boer, W. de; Laanbroek, H.J.

    1996-01-01

    The contribution of nitrifiers and denitrifiers to the nitrous oxide production in slurries of calcareous silt loam and river bank sediment at different oxygen concentrations was determined using acetylene as nitrification inhibitor. The addition of 10 Pa acetylene resulted in inhibition of

  17. Source Tracking of Nitrous Oxide using A Quantum Cascade Laser System in the Field and Laboratory Environments

    Science.gov (United States)

    Nitrous oxide is an important greenhouse gas and ozone depleting substance. Nitrification and denitrification are two major biological pathways that are responsible for soil emissions of N2O. However, source tracking of in-situ or laboratory N2O production is still challenging to...

  18. Effect of nitrous oxide on folate coenzyme distribution and de novo synthesis of thymidylate in human bone marrow cells

    NARCIS (Netherlands)

    A.A.M. Ermens (Anton); M. Schoester (Martijn); J. Lindemans (Jan); J. Abels

    1992-01-01

    markdownabstractAbstract The effect of nitrous oxide on intracellular folate metabolism of the human bone marrow was studied in vitro. Bone marrow cells, obtained from healthy volunteers, were incubated with 5 × 10−8m-[3H]5-formyltetrahydrofolate (5-formylTHF) for 18 hr to label intracellular

  19. Modeling Nitrous Oxide Production during Biological Nitrogen Removal via Nitrification and Denitrification: Extensions to the General ASM Models

    DEFF Research Database (Denmark)

    Ni, Bing-Jie; Ruscalleda, Maël; Pellicer i Nàcher, Carles

    2011-01-01

    Nitrous oxide (N2O) can be formed during biological nitrogen (N) removal processes. In this work, a mathematical model is developed that describes N2O production and consumption during activated sludge nitrification and denitrification. The well-known ASM process models are extended to capture N2O...

  20. Nitrous oxide fluxes from grassland in the Netherlands. 2. Effects of soil type, nitrogen fertilizer application and grazing

    NARCIS (Netherlands)

    Velthof, G.L.; Oenema, O.

    1995-01-01

    Intensively managed grasslands are potentially a large source of nitrous oxide (N2O) in the Netherlands because of the large nitrogen (N) input and the fairly wet soil conditions. To quantify the effects of soil type, N-fertilizer application and gra

  1. Nitrous oxide emissions from European agriculture - an analysis of variability and drivers of emissions from field experiments

    DEFF Research Database (Denmark)

    Rees, R M; Agustin, J; Alberti, G

    2013-01-01

    Nitrous oxide emissions from a network of agricultural experiments in Europe were used to explore the relative importance of site and management controls of emissions. At each site, a selection of management interventions were compared within replicated experimental designs in plot-based experime...

  2. A comparison of myogenic motor evoked responses to electrical and magnetic transcranial stimulation during nitrous oxide/opioid anesthesia

    NARCIS (Netherlands)

    Ubags, L. H.; Kalkman, C. J.; Been, H. D.; Koelman, J. H.; Ongerboer de Visser, B. W.

    1999-01-01

    Transcranial motor evoked potentials (tc-MEPs) are used to monitor spinal cord integrity intraoperatively. We compared myogenic motor evoked responses with electrical and magnetic transcranial stimuli during nitrous oxide/opioid anesthesia. In 11 patients undergoing spinal surgery, anesthesia was

  3. Detecting nitrous oxide reductase (nosZ) genes in soil metagenomes: method development and implications for the nitrogen cycle

    Science.gov (United States)

    Incomplete denitrification in soils represents a major source of nitrous oxide (N2O), a potent greenhouse gas. The key enzyme for mitigating N2O emissions is NosZ, which catalyzes N2O reduction to N2 and is generally attributed to denitrifiers. We recently described an “atypical” functional NosZ enz...

  4. Mitigation of methane and nitrous oxide emissions from animal operations: II. A review of manure management mitigation options

    NARCIS (Netherlands)

    Montes, F.; Meinen, R.; Dell, C.; Rotz, A.; Hristov, A.N.; Oh, J.; Waghorn, G.; Gerber, P.J.; Henderson, B.L.; Makkar, H.P.S.; Dijkstra, J.

    2013-01-01

    This review analyzes published data on manure management practices used to mitigate methane (CH4) and nitrous oxide (N2O) emissions from animal operations. Reducing excreted nitrogen (N) and degradable organic carbon (C) by diet manipulation to improve the balance of nutrient inputs with production

  5. Nitrification gene ratio and free ammonia explain nitrite and nitrous oxide production in urea-amended soils

    Science.gov (United States)

    Substantial efforts have been made to characterize soil nitrous oxide (N2O) emissions following N fertilizer addition. While nitrite (NO2-) is a central regulator of N2O production, NO2- and N2O responses to nitrogen (N) fertilizer amendments still cannot be readily predicted. Our objective was to...

  6. Nitrous oxide emission from urine-treated soil as influenced by urine composition and soil physical conditions

    NARCIS (Netherlands)

    Groenigen, van J.W.; Kuikman, P.J.; Groot, de W.J.M.; Velthof, G.L.

    2005-01-01

    Urine patches from cattle and sheep on pastures represent considerable, highly localized N applications. Subsequent nitrification and denitrification of the nitrogenous compounds may result in high nitrous oxide (N2O) emissions. Not much is known about the extent of these emissions, or about

  7. Mitigation of ammonia, nitrous oxide and methane emissions from manure management chains: a meta-analysis and integrated assessment

    NARCIS (Netherlands)

    Yong, Y.; Velthof, G.L.; Oenema, O.

    2015-01-01

    Livestock manure contributes considerably to global emissions of ammonia (NH3) and greenhouse gases (GHG), especially methane (CH4) and nitrous oxide (N2O). Various measures have been developed to mitigate these emissions, but most of these focus on one specific gas and/or emission source. Here, we

  8. Mitigating Sources of Indirect Nitrous Oxide Emissions from Tile Drain by On-Site Wood-Chip Bioreactors

    Science.gov (United States)

    Indirect nitrous oxide (N2O) emissions originating from nitrate-laden agricultural drainage waters represent a substantial fraction of total N2O emissions in the USA. Typical strategies to mitigate indirect N2O emissions are either improving fertilization methods or on-site treatment of drainage wat...

  9. On-site wood-chip bioreactors could reduce indirect nitrous oxide emissions from tile drain waters

    Science.gov (United States)

    Indirect nitrous oxide (N2O) emissions originating from nitrate-laden agricultural drainage waters represent approximately 21% of total N2O emissions in the USA. Typical strategies to mitigate indirect N2O emissions are either improving fertilization methods or on-site treatment of drainage water. R...

  10. Sheep Excreta as Source of Nitrous Oxide in Ryegrass Pasture in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Michely Tomazi

    2015-10-01

    Full Text Available ABSTRACT Livestock urine and dung are important components of the N cycle in pastures, but little information on its effect on soil nitrous oxide (N2O emissions is available. We conducted a short-term (39-day trial to quantify the direct N2O-N emissions from sheep excreta on an experimental area of ryegrass pasture growing on a Typic Paleudult in southern Brazil. Four rates of urine-N (161, 242, 323, and 403 kg ha-1 N and one of dung-N (13 kg ha-1 N were applied, as well as a control plot receiving no excreta. The N2O-N emission factor (EF = % of added N released as N2O-N for urine and dung was calculated, taking into account the N2O fluxes in the field, over a period of 39 days. The EF value of the urine and dung was used to estimate the emissions of N2O-N over a 90-day period of pasture in the winter under two grazing intensities (2.5 or 5.0 times the herbage intake potential of grazing lambs. The soil N2O-N fluxes ranged from 4 to 353 µg m-2h-1. The highest N2O-N fluxes occurred 16 days after application of urine and dung, when the highest soil nitrate content was also recorded and the water-filled pore space exceeded 60 %. The mean EF for urine was 0.25 % of applied N, much higher than that for dung (0.06 %. We found that N2O-N emissions for the 90-day winter pasture period were 0.54 kg ha-1 for low grazing intensity and 0.62 kg ha-1 for moderate grazing intensity. Comparison of the two forms of excreta show that urine was the main contributor to N2O-N emissions (mean of 36 %, whereas dung was responsible for less than 0.1 % of total soil N2O-N emissions.

  11. Differentiating Nitrification and Denitrification Sources of Nitrous Oxide Based on the Isotopomeric Composition

    Science.gov (United States)

    Sutka, R. L.; Pitt, A. J.; Ostrom, N. E.; Ostrom, P. H.; Gandhi, H.; Breznak, J.; Bergsma, T.

    2003-12-01

    Atmospheric concentrations of nitrous oxide (N2O) are steadily increasing primarily due to microbial activity in the environment. This has prompted efforts to apportion microbial sources of N2O to specific microbial processes. We investigated the isotopomeric composition N2O as a possible aid in differentiating microbial production mechanisms. Isotopomer refers not only to the isotopic abundance of N2O (δ 15N and δ 18O), but also to the 15N abundance within each of the nitrogen atoms comprising this molecule. In the linear N2O molecule, the central atom is referred to as alpha (α ) and the terminal nitrogen atom is referred to as beta (β ). The site preference refers to the difference between δ 15Nα and δ 15Nβ . We conducted experiments with pure bacterial cultures and agricultural soil mesocosms. Four microbial pathways for the production of N2O were investigated including hydroxylamine oxidation via autotrophic nitrifiers and methane oxidizers and nitrite reduction via denitrifiers and autotrophic nitrifiers. We used concentrated cell suspensions of a nitrifier (Nitrosomonas europaea), a methane oxidizer (Methylococcus capsulatus Bath) and a denitrifier that lacks N2O reductase (Pseudomonas chlororaphis). The average site preference of N2O produced by the oxidation of hydroxylamine by M. capsulatus Bath (5.5 +/- 3.5 per mil) and N. europaea(-2.3 +/- 1.9 per mil) was significantly different. Nitrous oxide produced by the reduction of nitrite by N. europaea and P. chlororaphis had a site preference of -8.3 +/- 3.6 per mil and -8.1 +/- 3.4 per mil, respectively. These results demonstrate that site preference can distinguish N2O produced by hydroxylamine oxidation by two distinct organisms. Furthermore, N2O derived by hydroxylamine oxidation differed significantly from that derived from nitrite reduction by the same nitrifying organism. Soil mesocosm experiments were used to determine that consumption of N2O did not change the isotopomeric composition. Since

  12. Direct and indirect nitrous oxide emissions from agricultural soils, 1990 - 2003. Background document on the calculation method for the Dutch National Inventory Report

    NARCIS (Netherlands)

    Hoek KW van der; Schijndel MW van; Kuikman PJ; MNP; Alterra; LVM

    2007-01-01

    Since 2005 the Dutch method to calculate the nitrous oxide emissions from agricultural soils has fully complied with the Intergovernmental Panel on Climate Change (IPCC) Good Practice Guidelines. In order to meet the commitments of the Convention on Climate Change and the Kyoto Protocol, nitrous

  13. Identification of nitrous oxide emissions from green areas of Chihuahua City irrigated with treated wastewater.

    Science.gov (United States)

    Navarro-Gómez, Carmen Julia; Herrera-Peraza, Eduardo F; Alcocer-Yamanaka, Victor Hugo; Collins-Martínez, Virginia H; Quiñones-Montenegro, Luisa Y; Trujillo-Navarrete, Balter; Espino-Valdes, Maria Socorro

    2013-03-01

    Since 2000, the city of Chihuahua had a distribution system of treated wastewater for irrigation of green areas and has replaced this water for processes that do not require the consumption of drinking water. This replacement was necessary in order to meet the growing demand for potable water which has exceeded the current supply of 700 L (184,88 gallons) per second. Nowadays it is necessary to identify and assess the risks to public health and the environment due to the substitution of drinking water by treated wastewater in the last 10yr. Treated wastewater contains compounds whose effects have not been evaluated when used for irrigation in public green areas. Therefore, it is not known whether there is a danger to the health of park visitors due to exposure and/or inhalation of the emitted gases, accidental ingestion of water, or impact to the environment. The purpose of the research, using an experimental prototype, is to identify the changes from nitrogen present in the treated wastewater to nitrous oxide. The research objective is the generation of data to simulate a regional scale at this stage, which will be analyzed and statistically validated using Minitab and Origin software. The experiment was performed using three different samples to compare water quality: drinking water treated wastewater, and water with nitrogen-based fertilizer (urea). Prototypes were filled with two types of soil: sand and clay Each type of water was sprinkled on the prototype, grass was planted in it, and the prototype was equipped with samplers to capture the gas in the root zone. The authors found high emissions of nitrous oxide in the clay-filled lysimeters, and climate and growing conditions of vegetation were the most important factors for producing nitrous oxide. Major problems in the ecosystem arise from solutions that are not based on environmental public policy research or experimentation. For example, before application a specific policy or regulation, research should

  14. Designing bioenergy crop buffers to mitigate nitrous oxide emissions and water quality impacts from agriculture

    Science.gov (United States)

    Gopalakrishnan, G.; Negri, C. M.

    2010-12-01

    There is a strong societal need to evaluate and understand the environmental aspects of bioenergy production, especially due to the significant increases in production mandated by many countries, including the United States. Bioenergy is a land-based renewable resource and increases in production are likely to result in large-scale conversion of land from current uses to bioenergy crop production; potentially causing increases in the prices of food, land and agricultural commodities as well as disruption of ecosystems. Current research on the environmental sustainability of bioenergy has largely focused on the potential of bioenergy crops to sequester carbon and mitigate greenhouse gas (GHG) emissions and possible impacts on water quality and quantity. A key assumption in these studies is that bioenergy crops will be grown in a manner similar to current agricultural crops such as corn and hence would affect the environment similarly. This study presents a systems approach where the agricultural, energy and environmental sectors are considered as components of a single system, and bioenergy crops are used to design multi-functional agricultural landscapes that meet society’s requirements for food, energy and environmental protection. We evaluate the production of bioenergy crop buffers on marginal land and using degraded water and discuss the potential for growing cellulosic bioenergy crops such as miscanthus and switchgrass in optimized systems such that (1) marginal land is brought into productive use; (2) impaired water is used to boost yields (3); clean freshwater is left for other uses that require higher water quality; and (4) feedstock diversification is achieved that helps ecological sustainability, biodiversity, and economic opportunities for farmers. The process-based biogeochemical model DNDC was used to simulate crop yield, nitrous oxide production and nitrate concentrations in groundwater when bioenergy crops were grown in buffer strips adjacent to

  15. Microbial production of nitrous oxide and nitric oxide in boreal peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Regina, K.

    1998-12-31

    Soils are an important source of nitrous oxide (N{sub 2}O) and nitric oxide (NO). N{sub 2}O is a greenhouse gas participating in both warming of the climate and the destruction of ozone, and NO is active in tropospheric chemistry. The fluxes and formation mechanisms of these gases in boreal Finnish peatlands were studied by both laboratory and field techniques. Special attention was paid to factors regulating their production, e.g. height of the water table, pH, temperature, nutrient level and nitrification activity. Both N{sub 2}O and NO fluxes were detected in the peatlands, some of which were sources of these trace gases and some sinks. The flux rates of N{sub 2}O ranged from negative values to several milligrammes per square metre per day. Natural peatlands were the lowest sources of N{sub 2}O, often showing negative fluxes, whereas sites drained for forestry some decades ago had markedly higher fluxes. A site drained for agriculture (grassland) was the highest source found. NO fluxes were observed on the two drained sites studied, a forested fen and the same field of grass, but not on a natural fen with a high water table. NO fluxes amounted to 16-30 % of the N{sub 2}O flux rates. The importance of the water table in regulating N{sub 2}0 fluxes was demonstrated in field and laboratory studies. It was shown in the laboratory that even a short lowering of the water table, for 14 weeks at 20 deg C, induced N{sub 2}0 fluxes from the fens that normally acted as sinks or only low sources. Raising the water table in peat monoliths from drained sites reduced the flux of N{sub 2}O. Nutrient-rich peatlands had much higher capacities for N{sub 2}O and NO production than poorer ones. The addition of KNO{sub 3}, NH{sub 4}Cl or urea to minerotrophic peat further increased the fluxes of N{sub 2}O and NO, and also nitrogen mineralisation. There was a clear connection between the fluxes of N{sub 2}0 and NO and nitrification activity measured as the numbers of nitrite

  16. Using a fourth-generation cavity enhanced spectrometer to isotopically investigate nitrous oxide emissions from biochar amended soils.

    Science.gov (United States)

    Grabenhofer, Jutta; Dercon, Gerd; Heiling, Maria; Mayr, Leo; Resch, Christian; Hood-Nowotny, Rebecca

    2016-04-01

    Research into the impacts of biochar on key processes in the nitrogen cycle is important to understand biochar's potential role in sustainable agriculture. There is conflicting evidence that biochar can reduce globally significant greenhouse gas emissions, especially N2O, one of the most important greenhouse gases in agriculture. However to date there is little information on the mechanisms involved. The source of N2O is dependent on the physical, chemical and biological status of the soil at a microbial scale and we need to understand how biochar influences it. Using the 15N2O gas flux method combined with gross rate measurements of nitrification and modelling, it should be possible to determine the parameters which drive N2O emissions and to evaluate the specific impact of biochar on these important N loss processes. To date the scope of isotopic studies on nitrous oxide emissions have been limited, due in part to technical and infrastructural access to complex and expensive mass spectrometry. With the advent of laser based systems these logistical and analytical constraints could be overcome and allow for a deeper and geographically more representative, understanding and assessment of the role of biochar in reducing nitrous oxide emissions from soil. In this study we have developed a simple method for investigated nitrous oxide emissions from soils amended with biochar, employing state of the art stable isotope techniques, using a fourth-generation cavity enhanced absorption technique a variant of conventional Cavity Ringdown Spectroscopy (CRDS) for measurement of isotopes of nitrous oxide. We will present methodologies used and results from these experiments, techniques that should path the way for a greater global understand nitrous oxide emissions from soils.

  17. Optimum time for intravenous cannulation after induction with sevoflurane, oxygen, and nitrous oxide in children without any premedication.

    Science.gov (United States)

    Hasan, Abm Kamrul; Sivasankar, Raman; Nair, Salil G; Hasan, Wamia U; Latif, Zulaidi

    2018-02-01

    Intravenous cannulation is usually done in children after inhalational induction with volatile anesthetic agents. The optimum time for safe intravenous cannulation after induction with sevoflurane, oxygen, and nitrous oxide has been studied in premedicated children, but there is no information for the optimum time for cannulation with inhalational induction in children without premedication. The aim of this study was to determine the optimum time for intravenous cannulation after the induction of anesthesia with sevoflurane, oxygen, and nitrous oxide in children without any premedication. This is a prospective, observer-blinded, up-and-down sequential allocation study in unpremedicated ASA grade 1 children aged 2-6 years undergoing elective dental surgery. Intravenous cannulation was attempted after inhalational induction with sevoflurane, oxygen, and nitrous oxide. The timing of cannulation was considered adequate if there was no movement, coughing, or laryngospasm. The cannulation attempt for the first child was set at 4 minutes after the loss of eyelash reflex and the time for intravenous cannulation was determined by the up-and-down method using 15 seconds as step size. Probit test was used to analyze the up-down sequences for the study. The adequate time for effective cannulation after induction with sevoflurane, oxygen, and nitrous oxide in 50% and 95% of patients was 53.02 seconds (95% confidence limits, 20.23-67.76 seconds) and 87.21 seconds (95% confidence limits, 70.77-248.03 seconds), respectively. We recommend waiting for 1 minute 45 seconds (105 seconds) after the loss of eyelash reflex before attempting intravenous cannulation in pediatric patients induced with sevoflurane, oxygen, and nitrous oxide without any premedication. © 2018 John Wiley & Sons Ltd.

  18. The influence of nitrous oxide on propofol dosage and recovery after total intravenous anaesthesia for day-case surgery.

    Science.gov (United States)

    Lindekaer, A L; Skielboe, M; Guldager, H; Jensen, E W

    1995-05-01

    We studied the influence of nitrous oxide on the maintenance dose of propofol and recovery characteristics in 42 patients, aged 18-62 years, ASA 1 or 2, scheduled for day case inguinal herniotomy. Using a double-blind, randomised design, patients received anaesthesia with propofol-alfentanil-vecuronium-oxygen and either nitrous oxide or room air (FIO2 = 0.30). The rate of propofol infusion was adjusted depending on anaesthetic depth as judged using standard clinical criteria; alfentanil was administered on a weight basis. Patients' lungs were manually ventilated after tracheal intubation and muscle relaxation was reversed at the end of surgery with neostigmine and atropine. A series of psychomotor tests was performed pre-operatively and 30 and 120 min postoperatively. The mean maintenance doses of propofol were 0.084 mg.kg-1.min-1 in the N2O group and 0.088 mg.kg-1.min-1 in the air group (p = 0.97). In the nitrous oxide group the mean (SD) interval to spontaneous eye opening was 13.1 (7.3) min compared to 8.1 (4.9) min in the air group (p = 0.01). Similarly, the interval until obtaining a standardised response was 13.5 (5.3) min and 9.8 min (5.4) in the nitrous oxide and air groups, respectively (p = 0.04). The addition of nitrous oxide to propofol-alfentanil-vecuronium anaesthesia does not reduce propofol requirements and prolongs early recovery compared to air.

  19. Interannual Variability of Methane and Nitrous Oxide in the North Pacific Subtropical Gyre

    Science.gov (United States)

    Wilson, Samuel T.; Ferrón, Sara; Karl, David M.

    2017-10-01

    The temporal variability of two important greenhouse gases, methane (CH4) and nitrous oxide (N2O), is reported for the upper water column at Station ALOHA in the North Pacific Subtropical Gyre. Measured concentrations of N2O conform to predicted values with an increase in saturation during the summer period. In contrast, CH4 is less predictable and shows an approximate 2 year transition from a state of oversaturation in surface waters to equilibrium values in 2015, implying a change in net CH4 production. The decrease in CH4 followed on from fluctuations in phosphate concentrations supporting the hypothesized link between microbial metabolism of phosphorus and the global biogeochemical cycle of CH4. At this current time, future trends in the net CH4 production in the North Pacific Subtropical Gyre are uncertain and specifically whether the surface ocean will be a net source or sink for CH4.

  20. Quantum cascade laser photoacoustic detection of nitrous oxide released from soils for biofuel production

    Science.gov (United States)

    Couto, F. M.; Sthel, M. S.; Castro, M. P. P.; da Silva, M. G.; Rocha, M. V.; Tavares, J. R.; Veiga, C. F. M.; Vargas, H.

    2014-12-01

    In order to investigate the generation of greenhouse gases in sugarcane ethanol production chain, a comparative study of N2O emission in artificially fertilized soils and soils free from fertilizers was carried out. Photoacoustic spectroscopy using quantum cascade laser with an emission ranging from 7.71 to 7.88 µm and differential photoacoustic cell were applied to detect nitrous oxide (N2O), an important greenhouse gas emitted from soils cultivated with sugar cane. Owing to calibrate the experimental setup, an initial N2O concentration was diluted with pure nitrogen and detection limit of 50 ppbv was achieved. The proposed methodology was selective and sensitive enough to detect N2O from no fertilized and artificially fertilized soils. The measured N2O concentration ranged from ppmv to ppbv.

  1. Ab initio intermolecular potential energy surface and thermophysical properties of nitrous oxide

    Energy Technology Data Exchange (ETDEWEB)

    Crusius, Johann-Philipp, E-mail: johann-philipp.crusius@uni-rostock.de; Hassel, Egon [Lehrstuhl für Technische Thermodynamik, Universität Rostock, 18059 Rostock (Germany); Hellmann, Robert, E-mail: robert.hellmann@uni-rostock.de; Bich, Eckard [Institut für Chemie, Universität Rostock, 18059 Rostock (Germany)

    2015-06-28

    We present an analytical intermolecular potential energy surface (PES) for two rigid nitrous oxide (N{sub 2}O) molecules derived from high-level quantum-chemical ab initio calculations. Interaction energies for 2018 N{sub 2}O–N{sub 2}O configurations were computed utilizing the counterpoise-corrected supermolecular approach at the CCSD(T) level of theory using basis sets up to aug-cc-pVQZ supplemented with bond functions. A site-site potential function with seven sites per N{sub 2}O molecule was fitted to the pair interaction energies. We validated our PES by computing the second virial coefficient as well as shear viscosity and thermal conductivity in the dilute-gas limit. The values of these properties are substantiated by the best experimental data.

  2. Nitrous Oxide Inhalation as a Fad—Dangers in Uncontrolled Sniffing for Psychedelic Effect

    Science.gov (United States)

    Dillon, John B.

    1967-01-01

    “LAUGHING GAS is the newest thing for kids seeking kicks,” the Stanford Daily reports. “They sniff it.” So begins a news story in the Los Angeles Times of 26 January 1967. The story continues: “It's the latest way to travel, or so say a growing group of devotees on the campus,” the university student paper said. “It can produce much the same effects as psychedelic drugs, they claim, and it's cheaper to obtain.” “One student said he buys the gas, nitrous oxide, from a medical supply house. `They think I am anesthetizing rats,' he explained. “Campus medical authorities said the gas, sniffed `in sufficient amounts... could produce all the states of anesthesia, including the final stage—death.'” PMID:6045472

  3. Quantifying nitrous oxide production pathways in wastewater treatment systems using isotope technology - A critical review.

    Science.gov (United States)

    Duan, Haoran; Ye, Liu; Erler, Dirk; Ni, Bing-Jie; Yuan, Zhiguo

    2017-10-01

    Nitrous oxide (N2O) is an important greenhouse gas and an ozone-depleting substance which can be emitted from wastewater treatment systems (WWTS) causing significant environmental impacts. Understanding the N2O production pathways and their contribution to total emissions is the key to effective mitigation. Isotope technology is a promising method that has been applied to WWTS for quantifying the N2O production pathways. Within the scope of WWTS, this article reviews the current status of different isotope approaches, including both natural abundance and labelled isotope approaches, to N2O production pathways quantification. It identifies the limitations and potential problems with these approaches, as well as improvement opportunities. We conclude that, while the capabilities of isotope technology have been largely recognized, the quantification of N2O production pathways with isotope technology in WWTS require further improvement, particularly in relation to its accuracy and reliability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Hemodynamics and Gas Exchange Effects of Inhaled Nitrous Oxide in Patients with Acute Respiratory Distress Syndrome

    Directory of Open Access Journals (Sweden)

    V. N. Poptsov

    2006-01-01

    Full Text Available Inhaled nitrous oxide (iNO therapy aimed at improving pulmonary oxygenizing function and at decreasing artificial ventilation (AV load has been used in foreign clinical practice in the past decade. The study was undertaken to evaluate the hemodynamic and gas exchange effects of iNO in acute respiratory distress syndrome (ARDS that developed after car-diosurgical operations. Fifty-eight (43 males and 15 females patients aged 21 to 76 (55.2±2.4 years were examined. The study has demonstrated that in 48.3% of cases, the early stage of ARDS is attended by the increased tone pulmonary vessels due to impaired NO-dependent vasodilatation. In these patients, iNO therapy is an effective therapeutic method for correcting hemodynamic disorders and lung oxygenizing function.

  5. The effects of plant diversity on nitrous oxide emissions in hydroponic microcosms

    Science.gov (United States)

    Sun, Hongying; Zhang, Chongbang; Song, Changchun; Chang, Scott X.; Gu, Baojing; Chen, Zhengxin; Peng, Changhui; Chang, Jie; Ge, Ying

    2013-10-01

    Previous studies have shown that plant diversity can improve the wastewater purification efficiency of constructed wetlands (CWs), but its effect on the nitrous oxide (N2O) emission in CWs has been unknown. To investigate the effect of plant diversity on the N2O emission, we established four plant species richness levels (each level containing 1, 2, 3 and 4 species, respectively) by using 96 hydroponic microcosms. Results showed that plant species richness enhanced the N2O emission, ranging from 27.1 to 115.4 μg N2O m-2 d-1, and improved nitrate removal (P 0.05), but improved nitrogen removal (P < 0.001). Hence, our study highlights the importance of both plant species richness and species identity in mediating the N2O emission and nitrogen removal in CWs.

  6. Interdisciplinary research in global biogeochemical cycling Nitrous oxide in terrestrial ecosystems

    Science.gov (United States)

    Norman, S. D.; Peterson, D. L.

    1984-01-01

    NASA has begun an interdisciplinary research program to investigate various aspects of Global Biology and Global Habitability. An important element selected for the study of global phenomena is related to biogeochemical cycling. The studies involve a collaboration with recognized scientists in the areas of plant physiology, microbiology, nutrient cycling theory, and related areas. Selected subjects of study include nitrogen cycling dynamics in terrestrial ecosystems with special attention to biosphere/atmosphere interactions, and an identification of sensitive response variables which can be used in ecosystem models based on parameters derived from remotely sensed variables. A description is provided of the progress and findings over the past two years. Attention is given to the characteristics of nitrous oxide emissions, the approach followed in the investigations, the selection of study sites, radiometric measurements, and research in Sequoia.

  7. Relationship between respiratory quotient, nitrification, and nitrous oxide emissions in a forced aerated composting process.

    Science.gov (United States)

    Tsutsui, Hirofumi; Fujiwara, Taku; Inoue, Daisuke; Ito, Ryusei; Matsukawa, Kazutsugu; Funamizu, Naoyuki

    2015-08-01

    We assessed the relationship between respiratory quotient (RQ) and nitrification and nitrous oxide (N2O) emission in forced aerated composting using lab-scale reactors. Relatively high RQ values from degradation of readily degradable organics initially occurred. RQ then stabilized at slightly lower values, then decreased. Continuous emission of N2O was observed during the RQ decrease. Correlation between nitrification and N2O emission shows that the latter was triggered by nitrification. Mass balances demonstrated that the O2 consumption of nitrification (∼24.8mmol) was slightly higher than that of CO2 emission (∼20.0mmol), indicating that the RQ decrease was caused by the occurrence of nitrification. Results indicate that RQ is a useful index, which not only reflects the bioavailability of organics but also predicts the occurrence of nitrification and N2O emission in forced aerated composting. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. [Contribution of fungi to soil nitrous oxide emission and their research methods: a review].

    Science.gov (United States)

    Huang, Ying; Long, Xi-En

    2014-04-01

    Nitrous oxide is an important greenhouse gas. Soil is one major emission source of N2O, which is a by-product of microorganisms-driven nitrification and denitrification processes. Extensive research has demonstrated archaea and bacteria are the predominant contributors in nitrification and denitrification. However, fungi may play a predominant role in the N transformation in a certain soil ecosystem. The fungal contribution to N2O production has been rarely investigated. Here, we reviewed the mechanism of N2O production by soil fungi. The mechanisms of denitrification, autotrophic and heterotrophic nitrification and their key microbes and functional genes were described, respectively. We discriminated the differences in denitrification between bacteria and fungi and discussed the methods being used to determine the contribution of fungi to soil N2O emission, including selective inhibitors, 15N stable isotope probing, isolation and pure culturing and uncultured molecular detection methods. The existing problems and research prospects were also presented.

  9. A compact QCL based methane and nitrous oxide sensor for environmental and medical applications.

    Science.gov (United States)

    Jahjah, Mohammad; Ren, Wei; Stefański, Przemysław; Lewicki, Rafał; Zhang, Jiawei; Jiang, Wenzhe; Tarka, Jan; Tittel, Frank K

    2014-05-07

    A methane (CH4) and nitrous oxide (N2O) sensor based on a sensitive, selective and well established technique of quartz enhanced photoacoustic spectroscopy (QEPAS) was developed for environmental and biomedical measurements. A thermoelectrically cooled (TEC) distributed feedback quantum cascade laser (DFB-QCL), capable of continuous wave (CW) mode hop free emission in the 7.83 μm wavelength range, was used as an excitation source. For the targeted CH4 and N2O absorption lines located at 1275.04 cm(-1) and 1275.49 cm(-1) detection limits (1σ) of 13 ppbv and 6 ppbv were achieved with a 1 second data acquisition time, respectively. Environmental data of CH4 and N2O mixing ratios acquired using the QEPAS sensor system are also reported.

  10. Standards development of global warming gas species: methane, nitrous oxide, trichlorofluoromethane, and dichlorodifluoromethane.

    Science.gov (United States)

    Rhoderick, George C; Dorko, William D

    2004-05-01

    Environmental scientists from federal agencies, such as the National Oceanic and Atmospheric Administration (NOAA), and academia have long suspected that increasing anthropogenic inputs of various trace gases into the atmosphere can cause changes in the earth's climate and protective ozone layer. Nitrous oxide and methane, cited in the Kyoto Protocol, as well astrichlorofluoromethane (CFC-11) and dichlorodifluoromethane (CFC-12), cited in the Montreal Protocol, are all greenhouse gases and are implicated in the destruction of the stratospheric ozone layer. The lack of national standards prompted research to determine the feasibility of preparing accurate and stable standards containing these four compounds. Development of these standards would support the measurement of these species by those in the atmospheric research community not having their own source of standards. A suite of eight primary gas standards containing methane, nitrous oxide, CFC-11, and CFC-12 in a balance of air were prepared gravimetrically to bracket the ambient atmospheric concentrations. The combined uncertainties (uc) were calculated from error propagation analysis that included the weighing data from the gravimetric preparation and other sources of error such as the purity analysis of the compounds and air matrix. The expanded uncertainties (U) for the gravimetric standards were < 0.5% as calculated from the equation U = kuc, where the coverage factor k is equal to 2 for a 95% confidence interval. Analyses of the suite of standards by gas chromatography with flame-ionization and electron capture detection resulted in average absolute residuals of < 0.25% from regression models. The NIST suite of eight gravimetric standards was used to determine the concentrations in two standardsfrom NOAA. Those analyses resulted in bias across the two laboratories of < or = 2.1%.

  11. Physical Processes and Nitrous Oxide Emissions Pre and Post-Freezing

    Science.gov (United States)

    Phillips, R. L.; Giltrap, D.; Kirschbaum, M.; Mcmillan, A. M.; Savage, K. E.; Davidson, E. A.

    2014-12-01

    Soil nitrous oxide (N2O) fluxes may be moderated by physical and biological processes, particularly when soils freeze and then thaw. There is a need to understand how physical processes affect above- canopy fluxes of N2O. There is also a need to understand the magnitude and duration of N2O emission peaks for agricultural fields, particularly the nitrogen-fixing legumes, which can produce and consume N2O in the plant root symbiosome. There are multiple potential sources of N2O, including bacteria and fungi in soil and in root symbiosomes. Further, N2O can be released when trapped in ice or dissolved in solution. These physical and biological processes can contribute to N2O fluxes measured above the canopy. In 2012-2013, we evaluated canopy, surface and belowground N2O data for a field seeded to lucerne (Medicago sativa). We used high-frequency data to determine above-canopy N2O fluxes using an Aerodyne Quantum Cascade Laser integrated with an eddy covariance system, and compared these with low-frequency flux and concentration data collected at the surface and belowground. Belowground moisture, temperature and soil data were used to partition measured N2O and CH4 into gaseous and dissolved phases. Pre and post-freeze data indicated the proportion of post-freeze flux previously trapped in ice. Nitrous oxide fluxes following a thaw event were compared with the amount of N2O trapped during freezing to determine the proportion of the flux resulting from previously trapped gases versus de novo N2O production.

  12. Do glucosinolate hydrolysis products reduce nitrous oxide emissions from urine affected soil?

    Science.gov (United States)

    Balvert, S F; Luo, J; Schipper, L A

    2017-12-15

    New Zealand agriculture is predominantly comprised of pastoral grazing systems and deposition of animal excreta during grazing has been identified as a major source of nitrous oxide (N2O) emissions. Nitrification inhibitors have been shown to significantly reduce nitrous oxide emissions from grazing pastoral systems, and some plants have been identified as having nitrification inhibiting properties. Brassica crops are one such example as they contain the secondary metabolite glucosinolate (GLS) whose hydrolysis products are thought to slow soil nitrogen cycling. Forage brassicas have been increasingly used to supplement the diet of grazing animals. The aim of this study was to determine if GLS hydrolysis products (phenylethyl isothiocyanate, 4-pent-1-yl isothiocyanate, 2-propenyl nitrile, 2 propenyl isothiocyanate, 4-pentene nitrile) produced in brassica crops reduced N2O emissions from soil amended with urea or animal urine. In the laboratory, some GLS hydrolysis products added with urea to soil were found to decrease N2O emissions and the most effective product (phenylethyl isothiocyante) reduced N2O emissions by 51% during the study. There was some evidence that the reduction in N2O emissions found in the lab could be attributed to inhibition of nitrification. Results suggest that the inhibition by GLS hydrolysis products was short-lived and, if considered for use, multiple applications may be necessary to achieve effective inhibition of N2O emissions. This reduction, however, was not observed under field conditions. Further investigation is required to test more GLS hydrolysis products to fully understand their impact on N2O emissions from urine affected soil. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Nitrogen source and placement effects on soil nitrous oxide emissions from no-till corn.

    Science.gov (United States)

    Halvorson, Ardell D; Del Grosso, Stephen J

    2012-01-01

    A nitrogen (N) source comparison study was conducted to further evaluate the effects of inorganic N source and placement on growing-season and non-crop period soil nitrous oxide (NO). Commercially available controlled-release N fertilizers were evaluated for their potential to reduce NO emissions from a clay loam soil compared with conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated no-till (NT) corn ( L.) production system. Controlled-release N fertilizers evaluated were: a polymer-coated urea (ESN), stabilized urea (SuperU), and UAN+AgrotainPlus (SuperU and AgrotainPlus contain nitrification and urease inhibitors). Each N source was surface band applied (202 kg N ha) near the corn row at emergence and watered into the soil the next day. Subsurface banded ESN (ESNssb) and check (no N applied) treatments were included. Nitrous oxide fluxes were measured during two growing seasons and after harvest using static, vented chambers. All N sources had significantly lower growing-season NO emissions than granular urea (0.7% of applied N), with UAN+AgrotainPlus (0.2% of applied N) and ESN (0.3% of applied N) having lower emissions than UAN (0.4% of applied N). Similar trends were observed when expressing NO emissions on a grain yield and N uptake basis. Corn grain yields were not different among N sources but were greater than the check. Selection of N fertilizer source can be a mitigation practice for reducing NO emissions in NT, irrigated corn in semiarid areas. In our study, UAN+AgrotainPlus consistently had the lowest level of NO emissions with no yield loss. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  14. Nitrogen source effects on nitrous oxide emissions from irrigated no-till corn.

    Science.gov (United States)

    Halvorson, Ardell D; Del Grosso, Stephen J; Francesco, Alluvione

    2010-01-01

    Nitrogen fertilization is essential for optimizing crop yields; however, it may potentially increase nitrous oxide (N2O) emissions. The study objective was to assess the ability of commercially available enhanced-efficiency N fertilizers to reduce N2O emissions following their application in comparison with conventional dry granular urea and liquid urea-ammonium nitrate (UAN) fertilizers in an irrigated no-till (NT) corn (Zea mays L.) production system. Four enhanced-efficiency fertilizers were evaluated: two polymer-coated urea products (ESN and Duration III) and two fertilizers containing nitrification and urease inhibitors (SuperU and UAN+AgrotainPlus). Nitrous oxide fluxes were measured during two growing seasons using static, vented chambers and a gas chromatograph analyzer. Enhanced-efficiency fertilizers significantly reduced growing-season N2O-N emissions in comparison with urea, including UAN. SuperU and UAN+AgrotainPlus had significantly lower N2O-N emissions than UAN. Compared with urea, SuperU reduced N2O-N emissions 48%, ESN 34%, Duration III 31%, UAN 27%, and UAN+AgrotainPlus 53% averaged over 2 yr. Compared with UAN, UAN+AgrotainPlus reduced N2O emissions 35% and SuperU 29% averaged over 2 yr. The N2O-N loss as a percentage of N applied was 0.3% for urea, with all other N sources having significantly lower losses. Grain production was not reduced by the use of alternative N sources. This work shows that enhanced-efficiency N fertilizers can potentially reduce N2O-N emissions without affecting yields from irrigated NT corn systems in the semiarid central Great Plains.

  15. Snowcover Influences Upon Episodic Release of Nitrous Oxide from Agricultural Soils During Spring Thaw

    Science.gov (United States)

    Helgason, W.; Farrell, R.; Ens, J.; Lemke, R.; David, C.

    2015-12-01

    In regions where agricultural soils seasonally freeze, such as the Canadian prairies, up to 60-70% of the annual nitrous oxide (N2O) emission can occur during the soil thaw period. The conditions responsible for this episodic release of N2O are poorly understood. In order to elucidate the influencing factors a replicated plot study was conducted in Outlook, Saskatchewan, Canada (51.5°N) during the 2014-2015 winter period. The study compared soil thermal conditions and soil gas fluxes (nitrous oxide and carbon dioxide) from plots that had the snow periodically removed and those on which snow was allowed to accumulate. Soil gas fluxes were measured using an automated chamber system (Gasmet DX4030 FTIR analyzer and Licor Li-8100 chamber system) and analyzer. Soil conditions were continuously monitored throughout the winter and thaw periods. Owing to the insulating effect of snow, the snow free plots were colder during the mid-winter period, but thawed 3-4 days earlier than the snow covered treatment. Following thaw, the snow-free plots were 2-3 degrees warmer than the snow-covered plots for 5-7 days before reaching a similar thermal regime. Due to the differences in the timing of soil thaw and the pre- and post-thaw thermal conditions, cumulative and peak N2O emissions were much higher from the plots that had been kept snow-free. These results suggest that agricultural practices which influence snow redistribution may have an effect upon spring soil gas fluxes. This study also highlights the importance of incorporating snowmelt and soil thaw physics into process-based greenhouse gas models.

  16. Response of nitric and nitrous oxide fluxes to N fertilizer application in greenhouse vegetable cropping systems in southeast China.

    Science.gov (United States)

    Zhang, Yaojun; Lin, Feng; Jin, Yaguo; Wang, Xiaofei; Liu, Shuwei; Zou, Jianwen

    2016-02-05

    It is of great concern worldwide that active nitrogenous gases in the global nitrogen cycle contribute to regional and global-scale environmental issues. Nitrous oxide (N2O) and nitric oxide (NO) are generally interrelated in soil nitrogen biogeochemical cycles, while few studies have simultaneously examined these two gases emission from typical croplands. Field experiments were conducted to measure N2O and NO fluxes in response to chemical N fertilizer application in annual greenhouse vegetable cropping systems in southeast China. Annual N2O and NO fluxes averaged 52.05 and 14.87 μg N m(-2) h(-1) for the controls without N fertilizer inputs, respectively. Both N2O and NO emissions linearly increased with N fertilizer application. The emission factors of N fertilizer for N2O and NO were estimated to be 1.43% and 1.15%, with an annual background emission of 5.07 kg N2O-N ha(-1) and 1.58 kg NO-N ha(-1), respectively. The NO-N/N2O-N ratio was significantly affected by cropping type and fertilizer application, and NO would exceed N2O emissions when soil moisture is below 54% WFPS. Overall, local conventional input rate of chemical N fertilizer could be partially reduced to attain high yield of vegetable and low N2O and NO emissions in greenhouse vegetable cropping systems in China.

  17. Impact of future nitrous oxide and carbon dioxide emissions on the stratospheric ozone layer

    Science.gov (United States)

    Stolarski, Richard S.; Douglass, Anne R.; Oman, Luke D.; Waugh, Darryn W.

    2015-03-01

    The atmospheric levels of human-produced chlorocarbons and bromocarbons are projected to make only small contributions to ozone depletion by 2100. Increases in carbon dioxide (CO2) and nitrous oxide (N2O) will become increasingly important in determining the future of the ozone layer. N2O increases lead to increased production of nitrogen oxides (NOx), contributing to ozone depletion. CO2 increases cool the stratosphere and affect ozone levels in several ways. Cooling decreases the rate of many photochemical reactions, thus slowing ozone loss rates. Cooling also increases the chemical destruction of nitrogen oxides, thereby moderating the effect of increased N2O on ozone depletion. The stratospheric ozone level projected for the end of this century therefore depends on future emissions of both CO2 and N2O. We use a two-dimensional chemical transport model to explore a wide range of values for the boundary conditions for CO2 and N2O, and find that all of the current scenarios for growth of greenhouse gases project the global average ozone to be larger in 2100 than in 1960.

  18. GOZCARDS Source Nitrous Oxide 1 month L3 10 degree Zonal Means on a Vertical Pressure Grid V1 (GozSmlpN2O) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOZCARDS Source Data for Nitrous Oxide 1 month L3 10 degree Zonal Averages on a Vertical Pressure Grid product (GozSmlpN2O) contains zonal means and related...

  19. MLS/Aura Level 2 Nitrous Oxide (N2O) Mixing Ratio V003 (ML2N2O) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2N2O is the EOS Aura Microwave Limb Sounder (MLS) standard product for nitrous oxide derived from radiances measured primarily by the 640 GHz radiometer (Band 12)...

  20. GOZCARDS Merged Nitrous Oxide 1 month L3 10 degree Zonal Means on a Vertical Pressure Grid V1 (GozMmlpN2O) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOZCARDS Merged Data for Nitrous Oxide 1 month L3 10 degree Zonal Averages on a Vertical Pressure Grid product (GozMmlpN2O) contains zonal means and related...

  1. HIRDLS/Aura Level 3 Nitrous Oxide (N2O) 1deg Lat Zonal Fourier Coefficients V007 (H3ZFCN2O) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Nitrous Oxide (N2O) Zonal Fourier Coefficients" version 7 data product (H3ZFCN2O) contains the entire mission (~3 years) of HIRDLS data...

  2. Does anaesthesia with nitrous oxide affect mortality or cardiovascular morbidity? A systematic review with meta-analysis and trial sequential analysis.

    Science.gov (United States)

    Imberger, G; Orr, A; Thorlund, K; Wetterslev, J; Myles, P; Møller, A M

    2014-03-01

    The role of nitrous oxide in modern anaesthetic practice is contentious. One concern is that exposure to nitrous oxide may increase the risk of cardiovascular complications. ENIGMA II is a large randomized clinical trial currently underway which is investigating nitrous oxide and cardiovascular complications. Before the completion of this trial, we performed a systematic review and meta-analysis, using Cochrane methodology, on the outcomes that make up the composite primary outcome. We used conventional meta-analysis and trial sequential analysis (TSA). We reviewed 8282 abstracts and selected 138 that fulfilled our criteria for study type, population, and intervention. We attempted to contact the authors of all the selected publications to check for unpublished outcome data. Thirteen trials had outcome data eligible for our outcomes. We assessed three of these trials as having a low risk of bias. Using conventional meta-analysis, the relative risk of short-term mortality in the nitrous oxide group was 1.38 [95% confidence interval (CI) 0.22-8.71] and the relative risk of long-term mortality in the nitrous oxide group was 0.94 (95% CI 0.80-1.10). In both cases, TSA demonstrated that the data were far too sparse to make any conclusions. There were insufficient data to perform meta-analysis for stroke, myocardial infarct, pulmonary embolus, or cardiac arrest. This systematic review demonstrated that we currently do not have robust evidence for how nitrous oxide used as part of general anaesthesia affects mortality and cardiovascular complications.

  3. Introduction of Inhaled Nitrous Oxide and Oxygen for Pain Management during Labour – Evaluation of Patientsʼ and Midwivesʼ Satisfaction

    Science.gov (United States)

    Dammer, U.; Weiss, C.; Raabe, E.; Heimrich, J.; Koch, M. C.; Winkler, M.; Faschingbauer, F.; Beckmann, M. W.; Kehl, S.

    2014-01-01

    Aim: Effective pain management during labour is important because pain affects the birth experience. Epidural analgesia is effective but often it may not be possible; however, inhaled analgesia offers another option. Use of inhaled nitrous oxide and oxygen for pain management in labour is well established in obstetrics but is still not used much in Germany. This study aimed to investigate the acceptance of the inhaled analgesia of inhaled nitrous oxide and oxygen by midwives and pregnant women during labour. Material and Methods: In this observational study carried out between April and September 2013, a total of 66 pregnant women received inhaled nitrous oxide and oxygen during labour on request and after prior assessment of suitability. After the birth, all of the women and the responsible midwives were interviewed about their experience and satisfaction with the inhaled analgesia. Results: A statistically significant reduction of pain was achieved with nitrous oxide and oxygen. The inhaled analgesia was mostly used by women who refused epidural analgesia. The likelihood of using inhaled nitrous oxide and oxygen again was reported as higher for patients who tolerated it well (p = 0.0129) and used it in the second stage of labour (p = 0.0003) and when bearing down (p = 0.0008). Conclusion: Inhaled nitrous oxide and oxygen is an effective method for pain management during labour and is accepted well by women in labour and by midwives. PMID:25100880

  4. Nitrous oxide production and consumption: regulation of gene expression by gas-sensitive transcription factors

    Science.gov (United States)

    Spiro, Stephen

    2012-01-01

    Several biochemical mechanisms contribute to the biological generation of nitrous oxide (N2O). N2O generating enzymes include the respiratory nitric oxide (NO) reductase, an enzyme from the flavo-diiron family, and flavohaemoglobin. On the other hand, there is only one enzyme that is known to use N2O as a substrate, which is the respiratory N2O reductase typically found in bacteria capable of denitrification (the respiratory reduction of nitrate and nitrite to dinitrogen). This article will briefly review the properties of the enzymes that make and consume N2O, together with the accessory proteins that have roles in the assembly and maturation of those enzymes. The expression of the genes encoding the enzymes that produce and consume N2O is regulated by environmental signals (typically oxygen and NO) acting through regulatory proteins, which, either directly or indirectly, control the frequency of transcription initiation. The roles and mechanisms of these proteins, and the structures of the regulatory networks in which they participate will also be reviewed. PMID:22451107

  5. Does zinc in livestock wastewater reduce nitrous oxide (N2O) emissions from mangrove soils?

    Science.gov (United States)

    Chen, Guang C; Tam, Nora F Y; Ye, Yong

    2014-11-15

    Zinc (Zn) affects nitrogen cycling but the effect of Zn in wastewater on the emission of nitrous oxide (N2O) from the soil has not been reported. This study compared N2O emissions from mangrove soil receiving livestock wastewater containing various Zn(2+) concentrations and evaluated how long the effects of Zn would last in these soil-wastewater microcosms. Significant increases in N2O flux were observed soon after the discharge of wastewater with a low Zn content. On the other hand, the flux was reduced significantly in the wastewater with high Zn levels but such inhibitory effect was not observed after tidal flushing. Continuous monitoring of the N2O fluxes also confirmed that the inhibitory effect of Zn was confined within a few hours and the fluxes recovered in 6-9 h after the wastewater was completely drained away. These results indicated that the inhibitory effect of Zn on N2O fluxes occurred immediately after wastewater discharge and disappeared gradually. In the surface soil, nitrate levels increased with the addition of wastewater but there was no significant accumulation of NH4(+)-N, irrespective of the Zn content in the wastewater. The study also showed that nitrification potential and immediate N2O emissions were inhibited by high Zn levels in the soil, but the total oxidation of ammonium to nitrate was not affected. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Nitrous oxide emission from polyculture constructed wetlands: Effect of plant species

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yanhua [School of Environmental Science and Engineering, Shanghai Jiaotong University, 800 Dong Chuan Road, Min Hang, Shanghai 200240 (China); Inamori, Ryuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan); Kong Hainan [School of Environmental Science and Engineering, Shanghai Jiaotong University, 800 Dong Chuan Road, Min Hang, Shanghai 200240 (China)], E-mail: remanda@126.com; Xu Kaiqin [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506 (Japan); State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan Unviversity, Wuhan 430072 (China); Inamori, Yuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan); Kondo, Takashi [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506 (Japan); Zhang Jixiang [School of Economics and Management, Southeast University, Nanjing, Jiangsu 210096 (China)

    2008-03-15

    Loss of nitrogen from the soil-plant system has raised environmental concern. This study assessed the fluxes of nitrous oxide (N{sub 2}O) in the subsurface flow constructed wetlands (CWs). To better understand the mechanism of N{sub 2}O emission, spatial distribution of ammonia-oxidizing bacteria (AOB) in four kinds of wetlands soil were compared. N{sub 2}O emission data showed large temporal and spatial variation ranging from -5.5 to 32.7 mg N{sub 2}O m{sup -2} d{sup -1}. The highest N{sub 2}O emission occurred in the cell planted with Phragmites australis and Zizania latifolia. Whereas, the lower emission rate were obtained in the cell planted with P. australis and Typha latifolia. These revealed that Z. latifolia stimulated the N{sub 2}O emission. Transportation of more organic matter and oxygen for AOB growth may be the reason. The study of AOB also supported this result, indicating that the root structure of Z. latifolia was favored by AOB for N{sub 2}O formation. - Zizania latifolia has a large contribution to global warming.

  7. Relationship between respiratory quotient, nitrification, and nitrous oxide emissions in a forced aerated composting process

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsui, Hirofumi, E-mail: jm-tsutsuih@kochi-u.ac.jp [Research and Education Faculty, Natural Sciences Cluster, Agriculture Unit, Kochi University, B200 Monobe, Nankoku, Kochi (Japan); Japan Science and Technology Agency, CREST (Japan); Fujiwara, Taku [Research and Education Faculty, Natural Sciences Cluster, Agriculture Unit, Kochi University, B200 Monobe, Nankoku, Kochi (Japan); Japan Science and Technology Agency, CREST (Japan); Inoue, Daisuke [Department of Health Science, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Sagamihara-Minami, Kanagawa (Japan); Japan Science and Technology Agency, CREST (Japan); Ito, Ryusei [Department of Environmental Engineering, Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido (Japan); Japan Science and Technology Agency, CREST (Japan); Matsukawa, Kazutsugu [Research and Education Faculty, Multidisciplinary Science Cluster, Life and Environmental Medicine Science Unit, Kochi University, B200 Monobe, Nankoku, Kochi (Japan); Japan Science and Technology Agency, CREST (Japan); Funamizu, Naoyuki [Department of Environmental Engineering, Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido (Japan); Japan Science and Technology Agency, CREST (Japan)

    2015-08-15

    Highlights: • RQ can be an indicator of N{sub 2}O emission in forced aerated composting process. • Emission of N{sub 2}O with nitrification was observed with RQ decrease. • Mass balances demonstrated the RQ decrease was caused by nitrification. • Conversion ratio of oxidized ammonia and total N to N{sub 2}O were ∼2.7%. - Abstract: We assessed the relationship between respiratory quotient (RQ) and nitrification and nitrous oxide (N{sub 2}O) emission in forced aerated composting using lab-scale reactors. Relatively high RQ values from degradation of readily degradable organics initially occurred. RQ then stabilized at slightly lower values, then decreased. Continuous emission of N{sub 2}O was observed during the RQ decrease. Correlation between nitrification and N{sub 2}O emission shows that the latter was triggered by nitrification. Mass balances demonstrated that the O{sub 2} consumption of nitrification (∼24.8 mmol) was slightly higher than that of CO{sub 2} emission (∼20.0 mmol), indicating that the RQ decrease was caused by the occurrence of nitrification. Results indicate that RQ is a useful index, which not only reflects the bioavailability of organics but also predicts the occurrence of nitrification and N{sub 2}O emission in forced aerated composting.

  8. Reduction of nitrous oxide emissions from partial nitrification process by using innovative carbon source (mannitol).

    Science.gov (United States)

    Zhang, Xinwen; Wang, Xiaoqing; Zhang, Jian; Huang, Xiaoyu; Wei, Dong; Lan, Wei; Hu, Zhen

    2016-10-01

    The purpose of this study was to evaluate the effect of mannitol as carbon source on nitrogen removal and nitrous oxide (N2O) emission during partial nitrification (PN) process. Laboratory-scale PN sequencing batch reactors (SBRs) were operated with mannitol and sodium acetate as carbon sources, respectively. Results showed that mannitol could remarkably reduce N2O-N emission by 41.03%, without influencing the removal efficiency of NH4(+)-N. However, it has a significant influence on nitrite accumulation ratio (NAR) and TN removal, which were 19.97% and 13.59% lower than that in PN with sodium acetate, respectively. Microbial analysis showed that the introduction of mannitol could increase the abundance of bacteria encoding nosZ genes. In addition, anti-oxidant enzymes (T-SOD, POD and CAT) activities were significantly reduced and the dehydrogenase activity had an obvious increase in mannitol system, indicating that mannitol could alleviate the inhibition of N2O reductase (N2OR) activities caused by high NO2(-)-N concentration. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Reduced Nitrous Oxide Emissions in Tomato Cropping Systems under Drip Irrigation and Fertigation

    Science.gov (United States)

    Kennedy, T.; Suddick, E. C.; Six, J. W.

    2011-12-01

    In California, agriculture and forestry account for 8% of the total greenhouse gas (GHG) emissions, of which 50% is accounted for by nitrous oxide (N2O). Furrow irrigation and high temperatures in the Central Valley, together with conventional fertilization, are ideal for the production of food, but also N2O. These conditions lead to high N2O fluxes, but also mean there is great potential to reduce N2O emissions by optimizing fertilizer use and irrigation practices. Improving fertilizer use by better synchronizing nitrogen (N) availability and crop demand can reduce N losses and fertilizer costs. Smaller, more frequent fertilizer applications can increase the synchrony between available soil N and crop N uptake. Fertigation allows for more control over how much N is being added and can therefore allow for better synchrony throughout the growing season. In our study, we determined how management practices, such as fertilization, irrigation, tillage and harvest, affect direct N2O emissions in typical tomato cropping systems. We evaluated two contrasting irrigation managements and their associated fertilizer application method, i.e. furrow irrigation and knife injection versus drip irrigation and fertigation. Across two tomato-growing seasons, we found that shifts in fertilizer and irrigation water management directly affect GHG emissions. Seasonal N2O fluxes were 3.4 times lower under drip versus furrow irrigation. In 2010, estimated losses of fertilizer N as N2O were 0.60 ± 0.06 kg N2O-N ha-1 yr-1 in the drip system versus 2.06 ± 0.11 N2O-N kg ha-1 yr-1 in the furrow system, which was equivalent to 0.29% and 0.87% of the added fertilizer, respectively. Carbon dioxide (CO2) emissions were also lower in the drip system (2.21 ± 0.16 Mg CO2-C ha-1 yr-1) than the furrow system (4.65 ± 0.23 Mg CO2-C ha-1 yr-1). Soil mineral N, dissolved organic carbon and soil moisture also varied between the two systems and correlated positively with N2O and CO2 emissions, depending

  10. Intercomparison of fast response commercial gas analysers for nitrous oxide flux measurements under field conditions

    Science.gov (United States)

    Rannik, Ü.; Haapanala, S.; Shurpali, N. J.; Mammarella, I.; Lind, S.; Hyvönen, N.; Peltola, O.; Zahniser, M.; Martikainen, P. J.; Vesala, T.

    2015-01-01

    Four gas analysers capable of measuring nitrous oxide (N2O) concentration at a response time necessary for eddy covariance flux measurements were operated from spring until winter 2011 over a field cultivated with reed canary grass (RCG, Phalaris arundinacea, L.), a perennial bioenergy crop in eastern Finland. The instruments were TGA100A (Campbell Scientific Inc.), CW-TILDAS-CS (Aerodyne Research Inc.), N2O / CO-23d (Los Gatos Research Inc.) and QC-TILDAS-76-CS (Aerodyne Research Inc.). The period with high emissions, lasting for about 2 weeks after fertilization in late May, was characterized by an up to 2 orders of magnitude higher emission, whereas during the rest of the campaign the N2O fluxes were small, from 0.01 to 1 nmol m-2 s-1. Two instruments, CW-TILDAS-CS and N2O / CO-23d, determined the N2O exchange with minor systematic difference throughout the campaign, when operated simultaneously. TGA100A produced the cumulatively highest N2O estimates (with 29% higher values during the period when all instruments were operational). QC-TILDAS-76-CS obtained 36% lower fluxes than CW-TILDAS-CS during the first period, including the emission episode, whereas the correspondence with other instruments during the rest of the campaign was good. The reasons for systematic differences were not identified, suggesting further need for detailed evaluation of instrument performance under field conditions with emphasis on stability, calibration and any other factors that can systematically affect the accuracy of flux measurements. The instrument CW-TILDAS-CS was characterized by the lowest noise level (with a standard deviation of around 0.12 ppb at 10 Hz sampling rate) as compared to N2O / CO-23d and QC-TILDAS-76-CS (around 0.50 ppb) and TGA100A (around 2 ppb). We identified that for all instruments except CW-TILDAS-CS the random error due to instrumental noise was an important source of uncertainty at the 30 min averaging level and the total stochastic error was frequently

  11. A comparison of the sedative effect of oral versus nasal midazolam combined with nitrous oxide in uncooperative children.

    Science.gov (United States)

    Musani, I E; Chandan, N V

    2015-10-01

    To compare a combination of oral midazolam (0.2 mg/kg body weight) and nitrous oxide-oxygen sedation with a combination of intranasal midazolam (0.1 mg/kg body weight) and nitrous oxide-oxygen sedation for effectiveness, patient acceptability and safety profile in controlling the behaviour of uncooperative children. Thirty children, 4-10 years of age, referred for dental treatment were included in the study with a crossover design. Each patient was sedated with a combination of either oral midazolam and nitrous oxide-oxygen sedation or intranasal midazolam and nitrous oxide-oxygen sedation at subsequent dental treatment visits. During the treatment procedure, the study recorded scales for drug acceptability, onset of sedation, acceptance of nasal mask, sedation, behavioural, safety, overall behaviour and alertness. The grade of acceptability of midazolam in both groups was consistently good. There was a significant difference (p < 0.001) in the time of onset of sedation, which was significantly quicker with the intranasal administration of midazolam. The mean time of onset for oral midazolam was 20.1 (17-25) min and for intranasal midazolam 12.1 (8-18) min. The efficacy profile of the present study included: acceptance of nasal mask, sedation score, crying levels, motor movements and overall behaviour scores. The results did not show any statistically significant differences. All the parameters were highly satisfactory. The difference in alertness was statistically significant (p value <0.05), being higher in the intranasal group than the oral group and suggestive of faster recovery using intranasal midazolam. The intranasal route of midazolam administration has a quick onset of action and a quick recovery of the patient from sedation as compared to the oral route of midazolam administration. Midazolam administered through the intranasal route is as effective as the oral route at a lower dosage. Therefore, it is an effective alternative to oral route for a

  12. Contamination of the operating room by anesthetic gases and vapors. II. Gas chromatographic analysis of nitrous oxide

    Energy Technology Data Exchange (ETDEWEB)

    Cattaneo, A.D.; Ferraiolo, G.; Rovatti, M.; Zattoni, J.; Donato, A.

    1981-12-01

    The contamination by nitrous oxide of an operating room atmosphere was studied in a number of experiments, in the absence of personnel and using a gaschromatographic method. The evacuating device of the anesthesia machine proved to be ineffective to overcome the hazard of leaks in the breathing system, whereas the air conditioning flow rates (12 outside air changes per hour) minimized waste anesthetic gas concentrations.

  13. A Study on Methane and Nitrous Oxide Emissions Characteristics from Anthracite Circulating Fluidized Bed Power Plant in Korea

    Directory of Open Access Journals (Sweden)

    Seehyung Lee

    2012-01-01

    Full Text Available In order to tackle climate change effectively, the greenhouse gas emissions produced in Korea should be assessed precisely. To do so, the nation needs to accumulate country-specific data reflecting the specific circumstances surrounding Korea’s emissions. This paper analyzed element contents of domestic anthracite, calorific value, and concentration of methane (CH4 and nitrous oxide (N2O in the exhaust gases from circulating fluidized bed plant. The findings showed the concentration of CH4 and N2O in the flue gas to be 1.85 and 3.25 ppm, respectively, and emission factors were 0.486 and 2.198 kg/TJ, respectively. The CH4 emission factor in this paper was 52% lower than default emission factor presented by the IPCC. The N2O emission factor was estimated to be 46% higher than default emission factor presented by the IPCC. This discrepancy can be attributable to the different methods and conditions of combustion because the default emission factors suggested by IPCC take only fuel characteristics into consideration without combustion technologies. Therefore, Korea needs to facilitate research on a legion of fuel and energy consumption facilities to develop country-specific emission factors so that the nation can have a competitive edge in the international climate change convention in the years to come.

  14. A Study on Methane and Nitrous Oxide Emissions Characteristics from Anthracite Circulating Fluidized Bed Power Plant in Korea

    Science.gov (United States)

    Lee, Seehyung; Kim, Jinsu; Lee, Jeongwoo; Jeon, Eui-Chan

    2012-01-01

    In order to tackle climate change effectively, the greenhouse gas emissions produced in Korea should be assessed precisely. To do so, the nation needs to accumulate country-specific data reflecting the specific circumstances surrounding Korea's emissions. This paper analyzed element contents of domestic anthracite, calorific value, and concentration of methane (CH4) and nitrous oxide (N2O) in the exhaust gases from circulating fluidized bed plant. The findings showed the concentration of CH4 and N2O in the flue gas to be 1.85 and 3.25 ppm, respectively, and emission factors were 0.486 and 2.198 kg/TJ, respectively. The CH4 emission factor in this paper was 52% lower than default emission factor presented by the IPCC. The N2O emission factor was estimated to be 46% higher than default emission factor presented by the IPCC. This discrepancy can be attributable to the different methods and conditions of combustion because the default emission factors suggested by IPCC take only fuel characteristics into consideration without combustion technologies. Therefore, Korea needs to facilitate research on a legion of fuel and energy consumption facilities to develop country-specific emission factors so that the nation can have a competitive edge in the international climate change convention in the years to come. PMID:22666126

  15. Direct Nitrous Oxide Emissions From Tropical And Sub-Tropical Agricultural Systems - A Review And Modelling Of Emission Factors

    Science.gov (United States)

    Albanito, Fabrizio; Lebender, Ulrike; Cornulier, Thomas; Sapkota, Tek B.; Brentrup, Frank; Stirling, Clare; Hillier, Jon

    2017-03-01

    There has been much debate about the uncertainties associated with the estimation of direct and indirect agricultural nitrous oxide (N2O) emissions in developing countries and in particular from tropical regions. In this study, we report an up-to-date review of the information published in peer-review journals on direct N2O emissions from agricultural systems in tropical and sub-tropical regions. We statistically analyze net-N2O-N emissions to estimate tropic-specific annual N2O emission factors (N2O-EFs) using a Generalized Additive Mixed Model (GAMM) which allowed the effects of multiple covariates to be modelled as linear or smooth non-linear continuous functions. Overall the mean N2O-EF was 1.2% for the tropics and sub-tropics, thus within the uncertainty range of IPCC-EF. On a regional basis, mean N2O-EFs were 1.4% for Africa, 1.1%, for Asia, 0.9% for Australia and 1.3% for Central & South America. Our annual N2O-EFs, estimated for a range of fertiliser rates using the available data, do not support recent studies hypothesising non-linear increase N2O-EFs as a function of applied N. Our findings highlight that in reporting annual N2O emissions and estimating N2O-EFs, particular attention should be paid in modelling the effect of study length on response of N2O.

  16. Nitrous Oxide and Nitrous Oxide-Free Low-Flow Anesthesia Using Bispectral Index Monitoring: Effects on Hemodynamics, Recovery Times, Volatile Anesthetic Consumption and Costs

    Directory of Open Access Journals (Sweden)

    Bengü Gülhan Köksal

    2010-12-01

    Full Text Available Aim: In this study, we aimed to compare the effects of desfluraneN2O and desflurane-fentanyl combinations on hemodynamics, recovery times, volatile anesthetic consumption and costs in low-flow desflurane anesthesia by bispectral index (BIS monitoring of depth of anesthesia. Methods: After approval of ethics committee and obtaining patient consents, 60 patients were divided into two equal groups randomly. Non-invasive blood pressure measurement, ECG, SpO2 and BIS were monitored. All patients received 10 L .min-1 100% oxygen with mask for 5 minute before intubation. 2 mg.kg-1 propofol, 2 μg.kg-1 fentanyl and 0.6 mg.kg-1 rocuronium bromide were administered at induction in both groups. Desfluran 6% was chosen for anesthesia maintenance. Group 1 received 50% O2-N2O mixture in 6 L.min-1 and Group 2 received 50% O2-air mixture in 6 L.min-1 as carrier gas. Low-flow anesthesia (1 L.min-1 was started after a 10-min period of initial high flow (6 L.min-1. In Group 2, infusion of fentanyl was begun in 1 μg.kg.hour-1 rate. Desflurane level was adjusted at a main BIS value of 40-60. Blood pressure, heart rate, FiO2, etO2, FiN22, EtN2O, FiCO2, EtCO2, Fidesfluran and Etdesflurane were recorded. Results: There were no significant differences between the two groups in terms of heart rate, arterial blood pressure, settings of desfluran and recovery time. BIS values (p<0.001 and anesthetic agent costs (p<0.001 were higher in Group 2. Conclusion: Using fentanyl infusion instead of nitrous oxide in low flow-anesthesia with desflurane did not alter the hemodynamic parameters. Fentanyl infusion with medical air-oxygen as carrier gas is an alternative technique, but increases BIS values and anesthetic agent costs. (The Medical Bulletin of Haseki 2010; 48: 132-8

  17. Nitrous Oxide Metabolism in Nitrate-Reducing Bacteria: Physiology and Regulatory Mechanisms.

    Science.gov (United States)

    Torres, M J; Simon, J; Rowley, G; Bedmar, E J; Richardson, D J; Gates, A J; Delgado, M J

    2016-01-01

    Nitrous oxide (N2O) is an important greenhouse gas (GHG) with substantial global warming potential and also contributes to ozone depletion through photochemical nitric oxide (NO) production in the stratosphere. The negative effects of N2O on climate and stratospheric ozone make N2O mitigation an international challenge. More than 60% of global N2O emissions are emitted from agricultural soils mainly due to the application of synthetic nitrogen-containing fertilizers. Thus, mitigation strategies must be developed which increase (or at least do not negatively impact) on agricultural efficiency whilst decrease the levels of N2O released. This aim is particularly important in the context of the ever expanding population and subsequent increased burden on the food chain. More than two-thirds of N2O emissions from soils can be attributed to bacterial and fungal denitrification and nitrification processes. In ammonia-oxidizing bacteria, N2O is formed through the oxidation of hydroxylamine to nitrite. In denitrifiers, nitrate is reduced to N2 via nitrite, NO and N2O production. In addition to denitrification, respiratory nitrate ammonification (also termed dissimilatory nitrate reduction to ammonium) is another important nitrate-reducing mechanism in soil, responsible for the loss of nitrate and production of N2O from reduction of NO that is formed as a by-product of the reduction process. This review will synthesize our current understanding of the environmental, regulatory and biochemical control of N2O emissions by nitrate-reducing bacteria and point to new solutions for agricultural GHG mitigation. © 2016 Elsevier Ltd. All rights reserved.

  18. Nitrate denitrification with nitrite or nitrous oxide as intermediate products: Stoichiometry, kinetics and dynamics of stable isotope signatures.

    Science.gov (United States)

    Vavilin, V A; Rytov, S V

    2015-09-01

    A kinetic analysis of nitrate denitrification by a single or two species of denitrifying bacteria with glucose or ethanol as a carbon source and nitrite or nitrous oxide as intermediate products was performed using experimental data published earlier (Menyailo and Hungate, 2006; Vidal-Gavilan et al., 2013). Modified Monod kinetics was used in the dynamic biological model. The special equations were added to the common dynamic biological model to describe how isotopic fractionation between N species changes. In contrast to the generally assumed first-order kinetics, in this paper, the traditional Rayleigh equation describing stable nitrogen and oxygen isotope fractionation in nitrate was derived from the dynamic isotopic equations for any type of kinetics. In accordance with the model, in Vidal-Gavilan's experiments, the maximum specific rate of nitrate reduction was proved to be less for ethanol compared to glucose. Conversely, the maximum specific rate of nitrite reduction was proved to be much less for glucose compared to ethanol. Thus, the intermediate nitrite concentration was negligible for the ethanol experiment, while it was significant for the glucose experiment. In Menyailo's and Hungate's experiments, the low value of maximum specific rate of nitrous oxide reduction gives high intermediate value of nitrous oxide concentration. The model showed that the dynamics of nitrogen and oxygen isotope signatures are responding to the biological dynamics. Two microbial species instead of single denitrifying bacteria are proved to be more adequate to describe the total process of nitrate denitrification to dinitrogen. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. The effects of nitrous oxide on vitamin B12 and homocysteine levels in methyltetrahydrofolate reductase gene mutation.

    Science.gov (United States)

    Hakimoglu, S; Hanci, V; Hakimoglu, Y; Cicek, S; Yurtlu, S; Okyay, R D; Ayoglu, H; Can, M; Mungan, G; Dursun, A; Turan, I

    2013-01-01

    We aimed to investigate the effects of nitrous oxide on plasma total homocysteine and vitamin B12 levels in patients with or without methyltetrahydrofolate reductase (MTHRF) gene mutation. After obtaining the ethics committee approval and written informed consents of patients, 93 patients between 18-70 years of age scheduled for surgery anticipated to last 1-4 hours were enrolled in the study. Patients with contraindications for nitrous oxide use were excluded. Preoperatively, blood samples were obtained from all patients for the determination of MTHFR gene mutation. Anesthesia induction was achieved with 3 mg.kg-1 of propofol and 1 µg.kg-1 of fentanyl. Anesthesia maintenance was performed with sevoflurane and with a carrier gas composed of 40 % O2 and 60 % N2O. Venous blood samples were obtained after venous canulation, and 24 hours after extubation for the analysis of plasma total homocysteine, vitamin B12 levels. Eighty-one patients were included in the study. Postoperative vitamin B12 levels were found to be significantly lower when compared with their preoperative levels (p0.05). Postoperative plasma total homocysteine levels were found to be significantly different between patients with operation times under and over 3 hours (p=0.028). We conclude that MTHRF gene polymorphism had no significant effects on postoperative plasma total homocysteine levels. However, we found that homocysteine levels might rise in patients who received general anesthesia with nitrous oxide for longer than 3 hours (Tab. 7, Ref. 26).

  20. Laparoscopic peritoneal dialysis catheter implantation using a Tenckhoff trocar under local anesthesia with nitrous oxide gas insufflation.

    Science.gov (United States)

    Keshvari, Amir; Najafi, Iraj; Jafari-Javid, Mihan; Yunesian, Masud; Chaman, Reza; Taromlou, Mohammadkazem Nouri

    2009-01-01

    Laparoscopic implantation of peritoneal dialysis catheters has many advantages over conventional methods. The ability to perform laparoscopy with the patient under local anesthesia allows renal failure patients, who ordinarily might not be considered candidates for general anesthesia, an opportunity to undergo this procedure. Using local anesthesia and nitrous oxide pneumoperitoneum, 175 catheters were implanted in long musculofascial tunnels under laparoscopic guidance to minimize the risk of catheter migration and flow dysfunction. Nitrous oxide pneumoperitoneum was well tolerated, allowing all procedures to be safely completed with the patients under local anesthesia. The overall 1- and 2-year catheter survival rates were 92.7% and 91.3%, respectively. The incidence of catheter tip migration and omental entrapment was 1.7% and 2.9%, respectively. Temporary pericatheter leak occurred in 7.4% of cases. Nitrous oxide insufflation enables safe performance of laparoscopic surgery with the patient under local anesthesia. Patients benefit from a minimally invasive technique with the assurance of obtaining successful long-term catheter function.

  1. Nitrous oxide emission from an agricultural field fertilized with liquid lagoonal swine effluent

    Science.gov (United States)

    Whalen, S. C.; Phillips, R. L.; Fischer, E. N.

    2000-06-01

    Contemporary agriculture is characterized by the intensive production of livestock in confined facilities and land application of stored waste as an organic fertilizer. Emission of nitrous oxide (N2O) from receiving soils is an important but poorly constrained term in the atmospheric N2O budget. In particular, there are few data for N2O emissions from spray fields associated with industrial scale swine production facilities that have rapidly expanded in the southeastern United States. In an intensive, 24-day investigation over three spray cycles, we followed the time course for changes in N2O emission and soil physicochemical variables in an agricultural field irrigated with liquid lagoonal swine effluent. The total N (535 mg L-1) of the liquid waste was almost entirely NH4+-N (>90%) and thus had a low mineralization potential. Soil profiles for nitrification and denitrification indicated that >90% of potential activity was localized in the surface 20 cm. Application of this liquid fertilizer to warm (19° to 28°C) soils in a form that is both readily volatilized and immediately utilizable by the endogenous N-cycling microbial community resulted in a sharp decline in soil NH4+-N and supported a rapid but short-lived (i.e., days) burst of nitrification, denitrification, and N2O emission. Nitrous oxide fluxes as high as 9200 μg N2O-N m-2 h-1 were observed shortly after fertilization, but emissions decreased to prefertilization levels within a few days. Poor correlations between N2O efflux and soil physicochemical variables (temperature, moisture, NO3--N, NH4+-N) and fertilizer loading rate point to the complexity of interacting factors affecting N2O production and emission. Total fertilizer N applied and N2O-N emitted were 29.7 g m-2 (297 kg N ha-1) and 395 mg m-2, respectively. The fractional loss of applied N to N2O (corrected for background emission) was 1.4%, in agreement with the mean of 1.25% reported for mineral fertilizers. The direct effects of fertilizer

  2. Mitigating Nitrous Oxide Emissions from Agricultural Landscape: The Role of Isotopic Techniques

    Science.gov (United States)

    Zaman, Mohammad; Nguyen, Minh Long

    2014-05-01

    A review of studies from agricultural landscapes indicate that intensification of agricultural activities, inefficient use of reactive nitrogen (N) fertilizers and irrigation water, increasing human population and changes in their diet (more protein demand), high stocking rate (number of grazing livestock per hectare) and intensive cultivation are the major influencing factors for nitrous oxide (N2O) emissions into the atmosphere. Nitrification (both autotrophic and heterotrophic), denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are the three major microbial processes that produce greenhouse N2O and non-greenhouse gas (N2) and can sometimes occur concurrently in a given soil system. The contribution of N2O production from each of these microbial processes is inconclusive because of the complex interactions between various microbial processes and the physical and chemical conditions in soil microsite (s). Nitrous oxide emissions across an agricultural landscape from different N inputs (chemical fertilizers and animal manure) and soil types are also extremely variable both temporally and spatially and range from 1-20% of the applied N and could therefore represent agronomic loss. The available conventional methods such as acetylene (C2H2) inhibition and helium (He) cannot accurately measure both N2O and N2 and their ratio in a given soil. The use of 15N stable isotopic technique offers the best option to measure both N2O and N2 and to identify their source (nitrification and denitrification) with a greater accuracy. Manipulating soil and fertilizer management practices can minimise these gaseous N losses. For example the combined use of urease inhibitor like (N-(n-butyl) thiophosphoric triamide (nBTPT) (trade name Agrotain®) and nitrification inhibitor dicyandiamide (DCD) with urea (100 kg N ha-1) or animal urine (600 kg N ha-1) was shown to reduce N losses by 39-53 % via denitrification-nitrification-DNRA processes. Other farm management

  3. Nitrous oxide fluxes and nitrogen cycling along a pasture chronosequence in Central Amazonia, Brazil

    Directory of Open Access Journals (Sweden)

    B. Wick

    2005-01-01

    Full Text Available We studied nitrous oxide (N2O fluxes and soil nitrogen (N cycling following forest conversion to pasture in the central Amazon near Santarém, Pará, Brazil. Two undisturbed forest sites and 27 pasture sites of 0.5 to 60 years were sampled once each during wet and dry seasons. In addition to soil-atmosphere fluxes of N2O we measured 27 soil chemical, soil microbiological and soil physical variables. Soil N2O fluxes were higher in the wet season than in the dry season. Fluxes of N2O from forest soils always exceeded fluxes from pasture soils and showed no consistent trend with pasture age. At our forest sites, nitrate was the dominant form of inorganic N both during wet and dry season. At our pasture sites nitrate generally dominated the inorganic N pools during the wet season and ammonium dominated during the dry season. Net mineralization and nitrification rates displayed large variations. During the dry season net immobilization of N was observed in some pastures. Compared to forest sites, young pasture sites (≤2 years had low microbial biomass N and protease activities. Protease activity and microbial biomass N peaked in pastures of intermediate age (4 to 8 years followed by consistently lower values in older pasture (10 to 60 years. The C/N ratio of litter was low at the forest sites (~25 and rapidly increased with pasture age reaching values of 60-70 at pastures of 15 years and older. Nitrous oxide emissions at our sites were controlled by C and N availability and soil aeration. Fluxes of N2O were negatively correlated to leaf litter C/N ratio, NH4+-N and the ratio of NO3--N to the sum of NO3--N + NH4+-N (indicators of N availability, and methane fluxes and bulk density (indicators of soil aeration status during the wet season. During the dry season fluxes of N2O were positively correlated to microbial biomass N, β-glucosidase activity, total inorganic N stocks and NH4+-N. In our study region, pastures of all age emitted less N2O than

  4. Antibiotics and Manure Effects on Microbial Communities Responsible for Nitrous Oxide Emissions from Grasslands

    Science.gov (United States)

    Semedo, M.; Song, B.; Sparrer, T.; Crozier, C.; Tobias, C. R.; Phillips, R. L.

    2015-12-01

    Agroecosystems are major contributors of nitrous oxide (N2O) emissions. Denitrification and nitrification are the primary pathways of N2O emission in soils. However, there is uncertainty regarding the organisms responsible for N2O production. Bacteria were previously considered the only microbial N2O source, however, current studies indicate that fungi also produce N2O by denitrification. Denitrifying bacteria can be a source or sink of N2O depending on the presence and expression of nitrous oxide reductase genes (nosZ), encoding for the enzyme converting N2O to N2. Fungal denitrification may produce only N2O as an end product due to missing the nosZ gene. Animal manures applied to agricultural fields can transfer antibiotics to soils as a result of antibiotic use in the livestock industry. These antibiotics target mostly bacteria and may promote fungal growth. The growth inhibition of denitrifying bacteria may favor fungal denitrifiers potentially enhancing N2O emissions. Our objective is to examine the effects of antibiotic exposure and manure fertilization on the microbial communities responsible for N2 and N2O production in grasslands. Soil slurry incubations were conducted with tetracycline at different concentrations. A mesocosm experiment was also performed with soil cores exposed to tetracycline and cow manure. Production of N2O and N2 was measured using gas chromatography with electron capture detector (GC-ECD) and isotope ratio mass spectrometry (IRMS), respectively. Antibiotic inhibition of soil N2 production was found to be dose dependent, reaching up to 80% inhibition with 1g Kg-1 of tetracycline treatment, while N2O production was enhanced up to 8 times. These results suggest higher fungal denitrification with a concomitant decrease in bacterial denitrification after antibiotic exposure. We also found higher N2O fluxes in the soil mesocosms treated with manure plus tetracycline. Quantitative PCR (qPCR) will be conducted to examine the changes in

  5. Nitrous Paraffin Hybrid Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Nitrous Oxide Paraffin Hybrid engine (N2OP) is a proposed technology designed to provide small launch vehicles with high specific impulse, indefinitely storable...

  6. Nitrous acid in a street canyon environment: Sources and contributions to local oxidation capacity

    Science.gov (United States)

    Yun, Hui; Wang, Zhe; Zha, Qiaozhi; Wang, Weihao; Xue, Likun; Zhang, Li; Li, Qinyi; Cui, Long; Lee, Shuncheng; Poon, Steven C. N.; Wang, Tao

    2017-10-01

    Nitrous acid (HONO) plays an important role in radical formation and photochemical oxidation processes in the boundary layer. However, its impact on the chemistry in a street canyon microenvironment has not been thoroughly investigated. In this study, we measured HONO in a street canyon in urban Hong Kong and used an observation-based box model (OBM) with the Master Chemical Mechanism (MCM v3.3.1) to investigate the contribution of HONO to local oxidation chemistry. The observed HONO mixing ratios were in the range of 0.4-13.9 ppbv, with an average of 3.91 ppbv in the daytime and 2.86 ppbv at night. A mean HONO/NOx emission ratio of 1.0% (±0.5%) from vehicle traffic was derived. OBM simulations constrained by the observed HONO showed that the maximum concentrations of OH, HO2, and RO2 reached 4.65 × 106, 4.40 × 106, and 1.83 × 106 molecules cm-3, which were 7.9, 5.0, and 7.5 times, respectively, the results in the case without HONO constrained. Photolysis of HONO contributed to 86.5% of the total primary radical production rates and led to efficient NO2 and O3 production under the condition of weak regional transport of O3. The formation of HNO3 contributed to 98.4% of the total radical termination rates. Our results suggest that HONO could significantly increase the atmospheric oxidation capacity in a street canyon and enhance the secondary formation of HNO3 and HCHO, which can damage outdoor building materials and pose health risks to pedestrians.

  7. A prospective, randomized controlled trial of conscious sedation using propofol combined with inhaled nitrous oxide for dental treatment.

    Science.gov (United States)

    Yokoe, Chizuko; Hanamoto, Hiroshi; Sugimura, Mitsutaka; Morimoto, Yoshinari; Kudo, Chiho; Niwa, Hitoshi

    2015-03-01

    Adverse reactions during propofol sedation include a decrease in arterial blood pressure, propofol-induced pain on injection, and airway complications. The purpose of this study was to investigate whether combined use of intravenous propofol and inhaled nitrous oxide could decrease the hypotensive and other adverse effects of propofol. We designed and implemented a prospective, randomized controlled trial. Patients undergoing dental procedures requiring intravenous sedation were randomly allocated to 2 groups: group P comprised those receiving sedation with propofol alone, and group N+P comprised those receiving sedation with 40% nitrous oxide inhalation and propofol. During the dental procedures, the sedation level was maintained at an Observer's Assessment of Alertness/Sedation scale score of 4 by adjusting propofol's target plasma concentration. Nitrous oxide inhalation was the predictor variable, whereas the hemodynamic changes, amount and concentration of propofol, and adverse events were the outcome variables. Eighty-eight patients were successfully analyzed without any complications. The total amount of propofol was significantly less in group N+P (249.8 ± 121.7 mg) than in group P (310.3 ± 122.4 mg) (P = .022), and the mean concentration of propofol was significantly less in group N+P (1.81 ± 0.34 μg/mL) than in group P (2.05 ± 0.44 μg/mL) (P = .006). The mean blood pressure reduction in group N+P (11.0 ± 8.0 mm Hg) was significantly smaller than that in group P (15.8 ± 10.2 mm Hg) (P = .034). Pain associated with the propofol injection and memory of the procedure were less in group N+P (P = .011 and P = .048, respectively). Nitrous oxide did not affect respiratory conditions or recovery characteristics. The results of this study suggest that nitrous oxide inhalation combined with propofol sedation attenuates the hypotensive effect and pain associated with propofol injections, along with potentiating the amnesic effect. Copyright © 2015 American

  8. Nitrous oxide emissions from temperate grassland ecosystems in the Northern and Southern Hemispheres

    Science.gov (United States)

    Müller, Christoph; Sherlock, Robert R.

    2004-03-01

    Nitrogen (N) fertilized or grazed grasslands in temperate regions of the Northern and Southern Hemisphere are important sources for atmospheric nitrous oxide (N2O). Following synthetic urine applications in a New Zealand grassland ecosystem, and ammonium (NH4+) and nitrate (NO3-) applications to a German grassland ecosystem, approximately 31, 16, and 5%, respectively, of the total emitted N2O (N2Otot) was produced by nitrification (N2Onit) with the rest being produced by denitrification (N2Oden). Analyses of the combined data set showed that 75% of all N2O emissions occurred above 60% water filled porosity (WFPS) and that more than 80% of all N2O emissions occurred at soil temperatures between 10° and 15°C. N2Oden emissions were associated with a WFPS value at around 80% at relatively low NO3- concentrations, while N2Onit emissions only occurred at high NH4+ levels shortly after N application at soil temperatures around 10°C. To increase the accuracy of predictions with simple mathematical models, such as the "hole-in-the-pipe-model," long-term validation data sets are needed where driving variables are related to measured N2Onit and N2Oden data.

  9. Nitrous oxide production and consumption potential in an agricultural and a forest soil

    DEFF Research Database (Denmark)

    Yu, Kewei; Struwe, Sten; Kjøller, Annelise

    2008-01-01

    Both a laboratory incubation experiment using soils from an agricultural field and a forest and field measurements at the same locations were conducted to determine nitrous oxide (N2O) production and consumption (reduction) potentials using the acetylene (C2H2) inhibition technique. Results from...... the laboratory experiment show that the agricultural soil had a stronger N2O reduction potential than the forest soil, as indicated by the N2O/N2 ratio in denitrification products. Without C2H2 inhibition, N2O could reach a maximum concentration of 51 and 296 ppmv in headspace of the agricultural and forest soil...... slurries, respectively. Addition of glucose decreased the maximum N2O concentration to 22 ppmv in headspace of the agricultural soil slurries, but increased to 520 ppmv in the forest soil slurries. Addition of exogenous N2O did not change such N2O accumulation maxima during the incubations. The field...

  10. Ecosystem respiration, methane and nitrous oxide fluxes from ecotopes in a rewetted extracted peatland in Sweden

    Directory of Open Access Journals (Sweden)

    S. Jordan

    2016-09-01

    Full Text Available Ecosystem respiration (carbon dioxide; CO2, methane (CH4 and nitrous oxide (N2O fluxes to the atmosphere were determined using an opaque closed chamber method within various ecotopes (vegetation covered, bare peat and open water in a rewetted extracted peatland and within an adjacent open poor fen in Sweden. Ecotopes had a significant impact on CO2 and CH4 fluxes to the atmosphere. Ecosystem respiration and CH4 emissions from the bare peat site, the constructed shallow lake and the open poor fen were low but were much higher from ecotopes with Eriophorum vaginatum tussocks and Eriophorum angustifolium. A combination of vascular plant cover and high soil temperatures enhanced ecosystem respiration, while a combination of vascular plant cover, high water table levels and high soil temperatures enhanced CH4 emissions. N2O emissions contributed little to total greenhouse gas (GHG fluxes from the soil-plant-water systems to the atmosphere. However, the overall climate impact of CH4 emissions from the study area did not exceed the impact of soil and plant respiration. With regard to management of extracted peatlands, the construction of a nutrient-poor shallow lake showed great potential for lowering GHG fluxes to the atmosphere.

  11. Nitrous oxide production in the eastern tropical South Pacific oxygen minimum zone

    Science.gov (United States)

    Ji, Qixing; Altabet, Mark; Arevalo-Martinez, Damian; Bange, Hermann; Ma, Xiao; Marandino, Christa; Sun, Mingshuang; Grundle, Damian

    2017-04-01

    Nitrous oxide (N2O) is an important climate active trace gas that contributes to both atmospheric warming and ozone destruction, and the ocean is an important source of N2O to the atmosphere. Dissolved oxygen concentrations play an important role in regulating N2O production in the ocean, such that under low oxygen conditions major shifts in the predominant production pathways (i.e. nitrification vs. denitrification) can occur and the magnitude of production may increase substantially. To this end, major oceanic oxygen minimum zones (OMZs) are responsible for a disproportionately high amount of marine N2O production. During the October 2015 ASTRA-OMZ cruise to the eastern tropical South Pacific (ETSP), one of the three major oceanic OMZs, we measured a suite of N2O parameters which included N2O concentrations, N2O production, and natural abundance N2O isotope (i.e. del 15N and del 18O) and isotopomer (i.e. 15N site-preference) signatures. Based on the results from these measurements, our presentation will demonstrate how N2O production and the different production pathways change along the oxygen concentration gradients from the oxygenated surface waters through the oxygen minimum layer. Our data could better constrain the importance of the ETSP-OMZ as source of marine N2O. Results from this work will provide insights into how N2O cycling responds to ocean deoxygenation as a result of climate change.

  12. Potential rates and environmental controls of denitrification and nitrous oxide production in a temperate urbanized estuary.

    Science.gov (United States)

    Teixeira, Catarina; Magalhães, Catarina; Boaventura, Rui A R; Bordalo, Adriano A

    2010-12-01

    Denitrification may play a major role in inorganic nitrogen removal from estuarine ecosystems, particularly in those subjected to increased nitrate and organic matter loads. The Douro estuary (NW Portugal) suffers from both problems: freshwater input of nitrate and organic load from untreated wastewater discharges. To assess how these factors might control sediment denitrification, a 12-month survey was designed. Denitrification potential and nitrous oxide (N(2)O) production were measured at different locations using the slurry acetylene blockage technique. Denitrification rate ranged from 0.4 to 38 nmol N g⁻¹ h⁻¹, increasing towards the river mouth following an urban pollution gradient. N(2)O production, a powerful greenhouse gas implicated on the destruction of the ozone layer, was significantly related with sediment organic matter and accounted for 0.5-47% of the N gases produced. Additional enrichment experiments were consistent with the results found in the environment, showing that sediments from the upper less urban stretch of the estuary, mostly sandy, respond positively to carbon and, inversely, in organic rich sediments from the lower estuary, the denitrification potential was limited by nitrate availability. The obtained results confirmed denitrification as an important process for the removal of nitrate in estuaries. The presence of wastewater discharges appears to stimulate nitrogen removal but also the production of N(2)O, a powerful greenhouse gas, exacerbating the N(2)O:N(2) ratio and thus should be controlled. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Thermocamera, a macroscopic method for the study of pollution with nitrous oxide in operating theatres.

    Science.gov (United States)

    Allander, C; Carlsson, P; Hallén, B; Ljungqvist, B; Norlander, O

    1981-02-01

    Nitrous oxide (N2O) is used in high concentrations in inhalation anaesthesia and can serve as a tracer of other, more potent anaesthetic agents polluting the air of operating theatres. It has the quality of absorbing infra-red light with a characteristic peak of 4.5 micrometer in the absorption spectrum. N2O in the operating-room atmosphere will absorb infra-red light emitted from a heat screen, and can therefore be registered by an infra-red-camera equipped with a filter eliminating waves outside the 4.5 micrometer waveband. The method was tested during paediatric inhalation anaesthesia. The infra-red-camera measurements are semi-quantitative and sensitive to an extinction of about 1000 ppmcm, comparable to a N2O concentration of 100 ppm measured by an infra-red N2O monitor. It was demonstrated that major pollution occurs during mask anaesthesia and after extubation. The polluting gas is insufficiently evacuated by the operating theatre ventilation. The method makes it possible to visualize the dispersion of spilled or leaking N2O, and is therefore of value when constructing and evaluating new scavenging equipment and in producing educational material.

  14. Prophylactic Modulation of Methane and Nitrous Oxide Emitted from Ruminants Livestock for Sustainable Animal Agriculture

    Directory of Open Access Journals (Sweden)

    J. Takahashi

    2014-12-01

    Full Text Available Major greenhouse gases (GHG attributed to animal agriculture sector are methane (CH4 and nitrous oxide (N2O, either generated from enteric fermentation or manure. The abatement mechanism of rumen CH4 emission may be divided to direct and indirect suppression to methanogens in the rumen.The most significant strategy to mitigate ruminal CH4 emission in indirect manner is to promote alternative metabolic pathway to dispose of the reducing power, competing with methanogenesis for H2 uptake. This includes prebiotics and probiotics (mostly propionate enhancers which consume metabolic hydrogen (H2 compete with methanogens and abate rumen methanogenesis in indirect manner. With regard to mitigate GHG emissions from manure, such waste has been proposed as a renewable energy and nitrogen sources through biogas plant. Furthermore, in advanced new biogas system, the ammonia stripping from digested slurry of livestock manure in biogas plant has been examined to apply to nitrogen recycling-options mitigating N2O emission. These options are: (1 ammonolysis on fiber-rich feedstuffs, (2 saccharification of the NH3 treated cellulose biomass to produce bio-ethanol, and (3 reformed hydrogen into NH3 fuel cell to generate electricity with proton exchange membrane fuel cell (PEM.

  15. Meta-analysis of environmental impacts on nitrous oxide release in response to N amendment

    Directory of Open Access Journals (Sweden)

    Emma eAronson

    2012-07-01

    Full Text Available Atmospheric nitrous oxide (N2O accounts for approximately 5% of the global greenhouse effect and destroys stratospheric ozone. Soils are the most important source of N2O, which is produced during nitrification and denitrification. To assess the impact of environmental variables and ecosystems on N2O flux, we performed a meta-analysis comparing N2O flux in N amended and matched control plots in non-agricultural soils. We found that N2O release increased with N amendment in the short term. Although there were few studies in shrubland, this ecosystem showed the greatest response. The N2O response to N amendment was greater in year-round studies and in studies with more measurements, but lower in longer studies. The N2O response was greater at higher latitudes and precipitation rates. We also observed an unexpected 55% decline in the N2O response to N amendment over the 23 years covered by the studies. This pattern may reflect a suppression of the N2O response from long-term N deposition accumulation, particularly in temperate regions. Although short-term increases in reactive N entering natural systems may cause positive feedbacks to the release of N2O, this effect may diminish over time in locations with high rates of N deposition.

  16. Soil nitrate reducing processes – drivers, mechanisms for spatial variation and significance for nitrous oxide production

    Directory of Open Access Journals (Sweden)

    Madeline Eleanore Giles

    2012-12-01

    Full Text Available The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate (NO3-¬ and production of the potent greenhouse gas, nitrous oxide (N2O. A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH and the size and community structure of nitrate reducing organisms responsible for the processes. There is an increasing understanding associated with many of these controls on flux through the nitrogen cycle in soil systems. However, there remains uncertainty about how the nitrate reducing communities are linked to environmental variables and the flux of products from these processes. The high spatial variability of environmental controls and microbial communities across small sub cm areas of soil may prove to be critical in determining why an understanding of the links between biotic and abiotic controls has proved elusive. This spatial effect is often overlooked as a driver of nitrate reducing processes. An increased knowledge of the effects of spatial heterogeneity in soil on nitrate reduction processes will be fundamental in understanding the drivers, location and potential for N2O production from soils.

  17. Nitrous oxide supersaturation at the liquid/air interface of animal waste

    Energy Technology Data Exchange (ETDEWEB)

    Makris, Konstantinos C., E-mail: kcmakris@gmail.co [Cyprus International Institute for the Environment and Public Health in association with the Harvard School of Public Health, 5 Iroon Street, Nicosia 1105 (Cyprus); Andra, Syam S. [Environmental Geochemistry Laboratory, University of Texas at San Antonio, San Antonio, TX (United States); Hardy, Michael; Sarkar, Dibyendu [Department of Earth and Environmental Studies, Montclair State University, Montclair, NJ (United States); Datta, Rupali [Department of Biological Sciences, Michigan Technological University, Houghton, MI (United States); Bach, Stephan B.H.; Mullens, Conor P. [Department of Chemistry, University of Texas at San Antonio, San Antonio, TX (United States)

    2009-12-15

    Concentrated animal feeding operations around the globe generate large amounts of nitrous oxide (N{sub 2}O) in the surrounding atmosphere. Liquid animal waste systems have received little attention with respect to N{sub 2}O emissions. We hypothesized that the solution chemistry of animal waste aqueous suspensions would promote conditions that lead to N{sub 2}O supersaturation at the liquid/air interface. The concentration of dissolved N{sub 2}O in poultry litter (PL) aqueous suspensions at 25 deg. C was 0.36 mug N{sub 2}O mL{sup -1}, at least an order of magnitude greater than that measured in water in equilibrium with ambient air, suggesting N{sub 2}O supersaturation. There was a nonlinear increase in the N{sub 2}O Henry constants of PL from 2810 atm/mole fraction at 35 deg. C to 17 300 atm/mole fraction at 41 deg. C. The extremely high N{sub 2}O Henry constants were partially ascribed to N{sub 2}O complexation with aromatic moieties. Complexed N{sub 2}O structures were unstable at temperatures > 35 deg. C, supplying the headspace with additional free N{sub 2}O concentrations. - Temperature-dependent N{sub 2}O supersaturation at the liquid/air interface of animal waste.

  18. Effects of temperature on nitrous oxide (N2O) emission from intensive aquaculture system.

    Science.gov (United States)

    Paudel, Shukra Raj; Choi, Ohkyung; Khanal, Samir Kumar; Chandran, Kartik; Kim, Sungpyo; Lee, Jae Woo

    2015-06-15

    This study examines the effects of temperature on nitrous oxide (N2O) emissions in a bench-scale intensive aquaculture system rearing Koi fish. The water temperature varied from 15 to 24 °C at interval of 3 °C. Both volumetric and specific rate for nitrification and denitrification declined as the temperature decreased. The concentrations of ammonia and nitrite, however, were lower than the inhibitory level for Koi fish regardless of temperature. The effects of temperature on N2O emissions were significant, with the emission rate and emission factor increasing from 1.11 to 1.82 mg N2O-N/d and 0.49 to 0.94 mg N2O-N/kg fish as the temperature decreased from 24 to 15 °C. A global map of N2O emission from aquaculture was established by using the N2O emission factor depending on temperature. This study demonstrates that N2O emission from aquaculture is strongly dependent on regional water temperatures as well as on fish production. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Pinus sylvestris as a missing source of nitrous oxide and methane in boreal forest.

    Science.gov (United States)

    Machacova, Katerina; Bäck, Jaana; Vanhatalo, Anni; Halmeenmäki, Elisa; Kolari, Pasi; Mammarella, Ivan; Pumpanen, Jukka; Acosta, Manuel; Urban, Otmar; Pihlatie, Mari

    2016-03-21

    Boreal forests comprise 73% of the world's coniferous forests. Based on forest floor measurements, they have been considered a significant natural sink of methane (CH4) and a natural source of nitrous oxide (N2O), both of which are important greenhouse gases. However, the role of trees, especially conifers, in ecosystem N2O and CH4 exchange is only poorly understood. We show for the first time that mature Scots pine (Pinus sylvestris L.) trees consistently emit N2O and CH4 from both stems and shoots. The shoot fluxes of N2O and CH4 exceeded the stem flux rates by 16 and 41 times, respectively. Moreover, higher stem N2O and CH4 fluxes were observed from wet than from dry areas of the forest. The N2O release from boreal pine forests may thus be underestimated and the uptake of CH4 may be overestimated when ecosystem flux calculations are based solely on forest floor measurements. The contribution of pine trees to the N2O and CH4 exchange of the boreal pine forest seems to increase considerably under high soil water content, thus highlighting the urgent need to include tree-emissions in greenhouse gas emission inventories.

  20. The variability of methane, nitrous oxide and sulfur hexafluoride in Northeast India

    Directory of Open Access Journals (Sweden)

    A. L. Ganesan

    2013-11-01

    Full Text Available High-frequency atmospheric measurements of methane (CH4, nitrous oxide (N2O and sulfur hexafluoride (SF6 from Darjeeling, India are presented from December 2011 (CH4/March 2012 (N2O and SF6 through February 2013. These measurements were made on a gas chromatograph equipped with a flame ionization detector and electron capture detector, and were calibrated on the Tohoku University, the Scripps Institution of Oceanography (SIO-98 and SIO-2005 scales for CH4, N2O and SF6, respectively. The observations show large variability and frequent pollution events in CH4 and N2O mole fractions, suggesting significant sources in the regions sampled by Darjeeling throughout the year. By contrast, SF6 mole fractions show little variability and only occasional pollution episodes, likely due to weak sources in the region. Simulations using the Numerical Atmospheric dispersion Modelling Environment (NAME particle dispersion model suggest that many of the enhancements in the three gases result from the transport of pollutants from the densely populated Indo-Gangetic Plains of India to Darjeeling. The meteorology of the region varies considerably throughout the year from Himalayan flows in the winter to the strong south Asian summer monsoon. The model is consistent in simulating a diurnal cycle in CH4 and N2O mole fractions that is present during the winter but absent in the summer and suggests that the signals measured at Darjeeling are dominated by large-scale (~100 km flows rather than local (<10 km flows.

  1. Effects of temperature, water content and nitrogen fertilisation on emissions of nitrous oxide by soils

    Science.gov (United States)

    Smith, K. A.; Thomson, P. E.; Clayton, H.; Mctaggart, I. P.; Conen, F.

    Nitrous oxide emissions were measured from several grassland and arable soils in the field, and from two of these soils and a forest soil transferred in large monoliths to a greenhouse. The effects of fertiliser N additions and of soil water content and temperature were investigated. Emissions were in the order grazed grassland>grassland cut for conservation>potatoes>cereal crops, and generally were higher than those from temperate natural ecosystems. Based on these data, agricultural soils constitute the major soil source of N 2O in the U.K. The highest emission recorded was 8 kg N 2O-N ha -1 over 10 months, from a grazed grassland site. Emissions varied from year to year, depending particularly on rainfall at the time of fertilisation. When soil mineral N was not limiting, exponential relationships between N 2O flux and both water-filled pore space (WFPS) and temperature were observed. The Q10 value for a sandy loam was 1.6, but ranged up to 12 for a clay loam soil at high WFPS. The high values were attributed to the increase in anaerobic zones where denitrification could take place, as respiratory demand for O 2 increased. A forest soil (peaty gley) showed an optimum water potential for N 2O emission. Diurnal fluctuations in emissions were associated with diurnal cycles in soil temperature, but with varying time lags, which could be explained by the N 2O being produced at different depths.

  2. Stimulation of nitrous oxide production resulted from soil fumigation with chloropicrin

    Science.gov (United States)

    Spokas, K.; Wang, D.

    Agricultural soils are a major source of the atmospheric greenhouse gas nitrous oxide (N 2O). Agronomic practices such as tillage and fertilizer applications can significantly affect the production and consumption of N 2O because of alteration in soil physical, chemical, and biochemical activities. Soil fumigation is an agronomic practice used to control soil-borne disease pathogens, weeds, plant-parasitic nematodes, and fungi. The strong impact of fumigants on soil microorganisms can indirectly affect the production and/or consumption of N 2O and would potentially alter net emissions from agricultural soils. Laboratory incubation and field soil fumigation studies were conducted to determine the potential impact of soil fumigation on the dynamics of N 2O production. Laboratory soil incubations showed an eight-fold increase in the production rate of N 2O as a consequence of chloropicrin (CP) fumigation. This stimulation effect was confirmed by a seven-fold increase in N 2O emission rates in field plots following CP fumigation. The mechanism of N 2O production appeared to be microbial related; however, additional work is needed to fully elucidate the pathways.

  3. Mitigating nitrous oxide emissions from tea field soil using bioaugmentation with a Trichoderma viride biofertilizer.

    Science.gov (United States)

    Xu, Shengjun; Fu, Xiaoqing; Ma, Shuanglong; Bai, Zhihui; Xiao, Runlin; Li, Yong; Zhuang, Guoqiang

    2014-01-01

    Land-use conversion from woodlands to tea fields in subtropical areas of central China leads to increased nitrous oxide (N2O) emissions, partly due to increased nitrogen fertilizer use. A field investigation of N2O using a static closed chamber-gas chromatography revealed that the average N2O fluxes in tea fields with 225 kg N ha(-1) yr(-1) fertilizer application were 9.4 ± 6.2 times higher than those of woodlands. Accordingly, it is urgent to develop practices for mitigating N2O emissions from tea fields. By liquid-state fermentation of sweet potato starch wastewater and solid-state fermentation of paddy straw with application of Trichoderma viride, we provided the tea plantation with biofertilizer containing 2.4 t C ha(-1) and 58.7 kg N ha(-1). Compared to use of synthetic N fertilizer, use of biofertilizer at 225 kg N ha(-1) yr(-1) significantly reduced N2O emissions by 33.3%-71.8% and increased the tea yield by 16.2%-62.2%. Therefore, the process of bioconversion/bioaugmentation tested in this study was found to be a cost-effective and feasible approach to reducing N2O emissions and can be considered the best management practice for tea fields.

  4. Mitigating Nitrous Oxide Emissions from Tea Field Soil Using Bioaugmentation with a Trichoderma viride Biofertilizer

    Directory of Open Access Journals (Sweden)

    Shengjun Xu

    2014-01-01

    Full Text Available Land-use conversion from woodlands to tea fields in subtropical areas of central China leads to increased nitrous oxide (N2O emissions, partly due to increased nitrogen fertilizer use. A field investigation of N2O using a static closed chamber-gas chromatography revealed that the average N2O fluxes in tea fields with 225 kg N ha−1 yr−1 fertilizer application were 9.4 ± 6.2 times higher than those of woodlands. Accordingly, it is urgent to develop practices for mitigating N2O emissions from tea fields. By liquid-state fermentation of sweet potato starch wastewater and solid-state fermentation of paddy straw with application of Trichoderma viride, we provided the tea plantation with biofertilizer containing 2.4 t C ha−1 and 58.7 kg N ha−1. Compared to use of synthetic N fertilizer, use of biofertilizer at 225 kg N ha−1 yr−1 significantly reduced N2O emissions by 33.3%–71.8% and increased the tea yield by 16.2%–62.2%. Therefore, the process of bioconversion/bioaugmentation tested in this study was found to be a cost-effective and feasible approach to reducing N2O emissions and can be considered the best management practice for tea fields.

  5. Does Plant Biomass Manipulation in Static Chambers Affect Nitrous Oxide Emissions from Soils?

    Science.gov (United States)

    Collier, Sarah M; Dean, Andrew P; Oates, Lawrence G; Ruark, Matthew D; Jackson, Randall D

    2016-03-01

    One of the most widespread approaches for measurement of greenhouse gas emissions from soils involves the use of static chambers. This method is relatively inexpensive, is easily replicated, and is ideally suited to plot-based experimental systems. Among its limitations is the loss of detection sensitivity with increasing chamber height, which creates challenges for deployment in systems including tall vegetation. It is not always possible to avoid inclusion of plants within chambers or to extend chamber height to fully accommodate plant growth. Thus, in many systems, such as perennial forages and biomass crops, plants growing within static chambers must either be trimmed or folded during lid closure. Currently, data on how different types of biomass manipulation affect measured results is limited. Here, we compare the effects of cutting vs. folding of biomass on nitrous oxide measurements in switchgrass ( L.) and alfalfa ( L.) systems. We report only limited evidence of treatment effects during discrete sampling events and little basis for concern that effects may intensify over time as biomass manipulation is repeatedly imposed. However, nonsignificant treatment effects that were consistently present amounted to significant overall trends in three out of the four systems studied. Such minor disparities in flux could amount to considerable quantities over time, suggesting that caution should be exercised when comparing cumulative emission values from studies using different biomass manipulation strategies. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  6. Aircraft emissions of methane and nitrous oxide during the alternative aviation fuel experiment.

    Science.gov (United States)

    Santoni, Gregory W; Lee, Ben H; Wood, Ezra C; Herndon, Scott C; Miake-Lye, Richard C; Wofsy, Steven C; McManus, J Barry; Nelson, David D; Zahniser, Mark S

    2011-08-15

    Given the predicted growth of aviation and the recent developments of alternative aviation fuels, quantifying methane (CH(4)) and nitrous oxide (N(2)O) emission ratios for various aircraft engines and fuels can help constrain projected impacts of aviation on the Earth's radiative balance. Fuel-based emission indices for CH(4) and N(2)O were quantified from CFM56-2C1 engines aboard the NASA DC-8 aircraft during the first Alternative Aviation Fuel Experiment (AAFEX-I) in 2009. The measurements of JP-8 fuel combustion products indicate that at low thrust engine states (idle and taxi, or 4% and 7% maximum rated thrusts, respectively) the engines emit both CH(4) and N(2)O at a mean ± 1σ rate of 170 ± 160 mg CH(4) (kg Fuel)(-1) and 110 ± 50 mg N(2)O (kg Fuel)(-1), respectively. At higher thrust levels corresponding to greater fuel flow and higher engine temperatures, CH(4) concentrations in engine exhaust were lower than ambient concentrations. Average emission indices for JP-8 fuel combusted at engine thrusts between 30% and 100% of maximum rating were -54 ± 33 mg CH(4) (kg Fuel)(-1) and 32 ± 18 mg N(2)O (kg Fuel)(-1), where the negative sign indicates consumption of atmospheric CH(4) in the engine. Emission factors for the synthetic Fischer-Tropsch fuels were statistically indistinguishable from those for JP-8.

  7. Iron: the forgotten driver of nitrous oxide production in agricultural soil.

    Directory of Open Access Journals (Sweden)

    Xia Zhu

    Full Text Available In response to rising interest over the years, many experiments and several models have been devised to understand emission of nitrous oxide (N2O from agricultural soils. Notably absent from almost all of this discussion is iron, even though its role in both chemical and biochemical reactions that generate N2O was recognized well before research on N2O emission began to accelerate. We revisited iron by exploring its importance alongside other soil properties commonly believed to control N2O production in agricultural systems. A set of soils from California's main agricultural regions was used to observe N2O emission under conditions representative of typical field scenarios. Results of multivariate analysis showed that in five of the twelve different conditions studied, iron ranked higher than any other intrinsic soil property in explaining observed emissions across soils. Upcoming studies stand to gain valuable information by considering iron among the drivers of N2O emission, expanding the current framework to include coupling between biotic and abiotic reactions.

  8. [Nitrous oxide emissions from municipal solid waste landfills and its measuring methodology: a review].

    Science.gov (United States)

    Jia, Ming-Sheng; Wang, Xiao-Jun; Chen, Shao-Hua

    2014-06-01

    Nitrous oxide (N2O) is one of three major greenhouse gases and the dominant ozone-depleting substance. Landfilling is the major approach for the treatment and disposal of municipal solid waste (MSW), while MSW landfills can be an important anthropogenic source for N2O emissions. Measurements at lab-scale and full-scale landfills have demonstrated that N2O can be emitted in substantial amounts in MSW landfills; however, a large variation in reported emission values exists. Currently, the mechanisms of N2O production and emission in landfills and its contribution to global warming are still lack of sufficient studies. Meanwhile, obtaining reliable N2O fluxes data in landfills remains a question with existing in-situ measurement techniques. This paper summarized relevant literature data on this issue and analyzed the potential production and emission mechanisms of N2O in traditional anaerobic sanitary landfill by dividing it into the MSW buried and the cover soil. The corresponding mechanisms in nitrogen removal bioreactor landfills were analyzed. Finally, the applicability of existing in-situ approaches measuring N2O fluxes in landfills, such as chamber and micrometeorological methods, was discussed and areas in which further research concerning N2O emissions in landfills was urgently required were proposed as well.

  9. Nitrous oxide fluxes at Cobb Mill Creek marsh on the eastern shore of Virginia

    Science.gov (United States)

    Funk, C. S.; Scanlon, T. M.

    2009-12-01

    Atmospheric nitrous oxide (N2O) concentrations are increasing at a rate unaccounted for with current detection methods and modeled budgets. Fertilizer nitrate (NO3-) additions in coastal watersheds could potentially lead to significant increases in N2O emissions from salt marsh ecosystems when naturally rapid microbial processes are subject to high levels of nitrate in stream and ground water. We employ a tunable diode laser trace gas analyzer (TGA) connected to a portable flow-through chamber to study N2O emissions at Cobb Mill Creek marsh, which drains a small agricultural watershed in Oyster, VA. Spatial variability of fluxes is determined by deploying the chamber at 12 sites across the marsh during exposure at low tide. Temporal variability is captured by deploying the chamber over a range of tidal regimes. Using these fluxes, we determine the spatial variability of N2O emissions (according to NO3- availability and degree of wetting which varies according to elevation), elucidate the factors that drive temporal variation of N2O emissions, and compare N2O fluxes from vegetated and non-vegetated areas of the marsh. Insight into the driving forces behind the pulsed nature of N2O emissions from salt water marshes can be used to improve modeled N2O budgets.

  10. Nitrous Oxide and Methane Fluxes Following Ammonium Sulfate and Vinasse Application on Sugar Cane Soil.

    Science.gov (United States)

    Paredes, Debora da S; Alves, Bruno J R; dos Santos, Marco A; Bolonhezi, Denizart; Sant'Anna, Selenobaldo A C; Urquiaga, Segundo; Lima, Magda A; Boddey, Robert M

    2015-09-15

    This study aimed to quantify nitrous oxide (N2O) and methane (CH4) emission/sink response from sugar cane soil treated with fertilizer nitrogen (N) and vinasse applied separately or in sequence, the latter being investigated with regard to the time interval between applications for a possible effect on emissions. The study was carried out in a traditional area of unburned sugar cane in São Paulo state, Brazil. Two levels of N fertilization (0 and 100 kg N ha(-1)) with no added vinasse and combined with vinasse additions at different times (100 m(-3) ha(-1) at 3 and 15 days after N fertilization) were evaluated. Methane and N2O fluxes were monitored for 211 days. On average, the soil was a sink for CH4, which was not affected by the treatments. Emissions of N2O were induced by N fertilizer and vinasse applications. For ammonium sulfate, 0.6% of the added N was emitted as N2O, while for vinasse, this ranged from 1.0 to 2.2%. Changes in N2O fluxes were detected the day after application of vinasse on the N fertilized areas, but although the emission factor (EF) was 34% greater, the EF was not significantly different from fertilizer N alone. Nevertheless, we recommend to not apply vinasse after N fertilization to avoid boosting N2O emissions.

  11. Influence of operatory size and nitrous oxide concentration upon scavenger effectiveness

    Energy Technology Data Exchange (ETDEWEB)

    Henry, R.J.; Primosch, R.E. (Department of Pediatric Dentistry, University of Florida College of Dentistry, J. Hillis Miller Health Center, Gainesville (United States))

    1991-09-01

    Concern regarding environmental health hazards for dental personnel chronically exposed to waste nitrous oxide (N2O) prompted this investigation. The influence on ambient N2O levels of scavenging, operatory size, and N2O concentration delivered to the patient was evaluated during treatment of 36 pediatric dental patients. The results showed that scavenging significantly reduced ambient N2O levels measured at 50-56 cm from the patient's nose. Scavenged ambient N2O levels were also observed to decrease when N2O concentrations administered to the patient were reduced from 50 to 30%. This concentration effect was not observed in the non-scavenged groups. ANOVA showed that operatory size exerted a non-significant influence on ambient N2O. The data collected during routine treatment of pediatric dental patients demonstrated that the scavenging system tested significantly reduced waste N2O in the operator's breathing zone, nearly approximating the 25-ppm recommendation established by the National Institute for Occupational Safety and Health (NIOSH).

  12. Effects of nitrous oxide on cerebral haemodynamics and metabolism during isoflurane anaesthesia in man

    Energy Technology Data Exchange (ETDEWEB)

    Algotsson, L.; Messeter, K. (Department of Anaesthesiology, University Hospital, Lund (Sweden)); Rosen, I. (Department of Clinical Neurophysiology, University Hospital, Lund (Sweden)); Holmin, T. (Department of Surgery, University Hospital, Lund (Sweden))

    1992-01-01

    Seven normoventilated and five hyperventilated healthy adults undergoing cholecystectomy and anaesthetized with methohexitone, fentanyl and pancuronium were studied with measurement of cerebral blood flow (CBF), cereal metabolic rate of oxygen (CMRo[sub 2]), and quantified electroencephalography (EEG) under two sets of conditions: (1) 1.7% end-tidal concentration of isoflurane in air/oxygen: (2) 0.85% end-tidal concentration of isoflurane in nitrous oxide (N[sub 2]O)/oxygen. The object was to study the effects of N[sub 2]O during isoflurane anaesthesia on cerebral circulation, metabolism and neuroelectric activity. N[sub 2]O in the anaesthetic gas mixture caused a 43% (P<0.05) increase in CBF during normocarbic conditions but no significant change during hypocapnia. CMRo[sub 2] was not significantly altered by N[sub 2]O. EEG demonstrated an activated pattern with decreased low frequency activity and increased high frequency activity. The results confirm that N[sub 2]O is a potent cerebral vasodilator in man, although the mechanisms underlying the effects on CBF are still unclear. (au).

  13. Stratospheric ozone depletion due to nitrous oxide: influences of other gases.

    Science.gov (United States)

    Portmann, R W; Daniel, J S; Ravishankara, A R

    2012-05-05

    The effects of anthropogenic emissions of nitrous oxide (N(2)O), carbon dioxide (CO(2)), methane (CH(4)) and the halocarbons on stratospheric ozone (O(3)) over the twentieth and twenty-first centuries are isolated using a chemical model of the stratosphere. The future evolution of ozone will depend on each of these gases, with N(2)O and CO(2) probably playing the dominant roles as halocarbons return towards pre-industrial levels. There are nonlinear interactions between these gases that preclude unambiguously separating their effect on ozone. For example, the CH(4) increase during the twentieth century reduced the ozone losses owing to halocarbon increases, and the N(2)O chemical destruction of O(3) is buffered by CO(2) thermal effects in the middle stratosphere (by approx. 20% for the IPCC A1B/WMO A1 scenario over the time period 1900-2100). Nonetheless, N(2)O is expected to continue to be the largest anthropogenic emission of an O(3)-destroying compound in the foreseeable future. Reductions in anthropogenic N(2)O emissions provide a larger opportunity for reduction in future O(3) depletion than any of the remaining uncontrolled halocarbon emissions. It is also shown that 1980 levels of O(3) were affected by halocarbons, N(2)O, CO(2) and CH(4), and thus may not be a good choice of a benchmark of O(3) recovery.

  14. Effect of nitrous oxide on fentanyl consumption in burned patients undergoing dressing change

    Directory of Open Access Journals (Sweden)

    Arthur Halley Barbosa do Vale

    2016-02-01

    Full Text Available BACKGROUND AND OBJECTIVES: Thermal injuries and injured areas management are important causes of pain in burned patients, requiring that these patients are constantly undergoing general anesthesia for dressing change. Nitrous oxide (N2O has analgesic and sedative properties; it is easy to use and widely available. Thus, the aim of this study was to evaluate the analgesic effect of N2O combined with fentanyl in burned patients during dressing change. METHOD: After approval by the institutional Ethics Committee, 15 adult burned patients requiring daily dressing change were evaluated. Patient analgesia was controlled with fentanyl 0.0005% administered by intravenous pump infusion on-demand. Randomly, in one of the days a mixture of 65% N2O in oxygen (O2 was associated via mask, with a flow of 10 L/min (N2O group and on the other day only O2 under the same flow (control group. RESULTS: No significant pain reduction was seen in N2O group compared to control group. VAS score before dressing change was 4.07 and 3.4, respectively, in N2O and control groups. Regarding pain at the end of the dressing, patients in N2O group reported pain severity of 2.8; while the control group reported 2.87. There was no significant difference in fentanyl consumption in both groups. CONCLUSIONS: The association of N2O was not effective in reducing opioid consumption during dressing changes.

  15. Potential of nitrous oxide recovery from an aerobic/oxic/anoxic SBR process.

    Science.gov (United States)

    Zhao, Jianqiang; Huang, Nan; Hu, Bo; Jia, Luwei; Ge, Guanghuan

    2016-01-01

    A single sequencing batch reactor (SBR) with an operating mode of anaerobic/oxic/anoxic (A/O/A) was developed to determine a simpler process to recover nitrous oxide (N2O) from synthetic wastewater containing ammonia and glucose. This SBR system was initiated in A/O mode to implement nitritation (ammonia to nitrite) and then switched to A/O/A mode. Using measurements of the dissolved N2O concentration and release rate, the total production and conversion rate of N2O were calculated to reveal the potential of producing and recovering N2O in the extended anoxic phase. Results showed that the A/O/A SBR could convert the majority of the nitrite available in the system into N2O by heterotrophic denitritation over longer anoxic periods, and a conversion rate of 77% could be achieved. As a consequence, the A/O/A SBR presents potential ability to produce and recover N2O from wastewater containing ammonia and organic carbon.

  16. Nitrous Oxide sedation for intra-articular injection in juvenile idiopathic arthritis

    Directory of Open Access Journals (Sweden)

    Harel Liora

    2008-01-01

    Full Text Available Abstract Background Intra-articular corticosteroid injection in juvenile idiopathic arthritis (JIA is often associated with anxiety and pain. Recent reports advocate the use of nitrous oxide (NO, a volatile gas with analgesic, anxiolytic and sedative properties. Objective To prospectively evaluate the effectiveness and safety of NO analgesia for intra-articular corticosteroid injection in JIA, and to assess patients and staff satisfaction with the treatment. Methods NO was administered to JIA patients scheduled for joint injection. The patient, parent, physician and nurse completed visual-analog scores (VAS (0–10 for pain, and a 5-point satisfaction scale. Change in heart rate (HR during the procedure was recorded in order to examine physiologic response to pain and stress. Patient's behavior and adverse reactions were recorded. Results 54 procedures (72 joints were performed, 41 females, 13 males; 39 Jewish, 13 Arab; mean age was 12.2 ± 4.7 year. The median VAS pain score for patients, parents, physicians and nurses was 3. The HR increased ≥ 15% in 10 patients. They had higher VAS scores as evaluated by the staff. The median satisfaction level of the parents and staff was 3.0 and 5.0 respectively. Adverse reactions were mild. Conclusion NO provides effective and safe sedation for JIA children undergoing intra-articular injections.

  17. Assessment of nitric oxide (NO) redox reactions contribution to nitrous oxide (N2 O) formation during nitrification using a multispecies metabolic network model.

    Science.gov (United States)

    Perez-Garcia, Octavio; Chandran, Kartik; Villas-Boas, Silas G; Singhal, Naresh

    2016-05-01

    Over the coming decades nitrous oxide (N2O) is expected to become a dominant greenhouse gas and atmospheric ozone depleting substance. In wastewater treatment systems, N2O is majorly produced by nitrifying microbes through biochemical reduction of nitrite (NO2(-)) and nitric oxide (NO). However it is unknown if the amount of N2O formed is affected by alternative NO redox reactions catalyzed by oxidative nitrite oxidoreductase (NirK), cytochromes (i.e., P460 [CytP460] and 554 [Cyt554 ]) and flavohemoglobins (Hmp) in ammonia- and nitrite-oxidizing bacteria (AOB and NOB, respectively). In this study, a mathematical model is developed to assess how N2O formation is affected by such alternative nitrogen redox transformations. The developed multispecies metabolic network model captures the nitrogen respiratory pathways inferred from genomes of eight AOB and NOB species. The performance of model variants, obtained as different combinations of active NO redox reactions, was assessed against nine experimental datasets for nitrifying cultures producing N2O at different concentration of electron donor and acceptor. Model predicted metabolic fluxes show that only variants that included NO oxidation to NO2(-) by CytP460 and Hmp in AOB gave statistically similar estimates to observed production rates of N2O, NO, NO2(-) and nitrate (NO3(-)), together with fractions of AOB and NOB species in biomass. Simulations showed that NO oxidation to NO2(-) decreased N2O formation by 60% without changing culture's NO2(-) production rate. Model variants including NO reduction to N2O by Cyt554 and cNor in NOB did not improve the accuracy of experimental datasets estimates, suggesting null N2O production by NOB during nitrification. Finally, the analysis shows that in nitrifying cultures transitioning from dissolved oxygen levels above 3.8 ± 0.38 to <1.5 ± 0.8 mg/L, NOB cells can oxidize the NO produced by AOB through reactions catalyzed by oxidative NirK. © 2015 Wiley Periodicals, Inc.

  18. The biosynthesis of nitrous oxide in the green alga Chlamydomonas reinhardtii.

    Science.gov (United States)

    Plouviez, Maxence; Wheeler, David; Shilton, Andy; Packer, Michael A; McLenachan, Patricia A; Sanz-Luque, Emanuel; Ocaña-Calahorro, Francisco; Fernández, Emilio; Guieysse, Benoit

    2017-07-01

    Over the last decades, several studies have reported emissions of nitrous oxide (N2 O) from microalgal cultures and aquatic ecosystems characterized by a high level of algal activity (e.g. eutrophic lakes). As N2 O is a potent greenhouse gas and an ozone-depleting pollutant, these findings suggest that large-scale cultivation of microalgae (and possibly, natural eutrophic ecosystems) could have a significant environmental impact. Using the model unicellular microalga Chlamydomonas reinhardtii, this study was conducted to investigate the molecular basis of microalgal N2 O synthesis. We report that C. reinhardtii supplied with nitrite (NO2- ) under aerobic conditions can reduce NO2- into nitric oxide (NO) using either a mitochondrial cytochrome c oxidase (COX) or a dual enzymatic system of nitrate reductase (NR) and amidoxime-reducing component, and that NO is subsequently reduced into N2 O by the enzyme NO reductase (NOR). Based on experimental evidence and published literature, we hypothesize that when nitrate (NO3- ) is the main Nitrogen source and the intracellular concentration of NO2- is low (i.e. under physiological conditions), microalgal N2 O synthesis involves the reduction of NO3- to NO2- by NR followed by the reduction of NO2- to NO by the dual system involving NR. This microalgal N2 O pathway has broad implications for environmental science and algal biology because the pathway of NO3- assimilation is conserved among microalgae, and because its regulation may involve NO. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  19. Impact of dicyandiamide on emissions of nitrous oxide, nitric oxide and ammonia from agricultural field in the North China Plain.

    Science.gov (United States)

    Zhou, Yizhen; Zhang, Yuanyuan; Tian, Di; Mu, Yujing

    2016-02-01

    Nitrous oxide (N2O), nitric oxide (NO) and ammonia (NH3) emissions from an agricultural field in the North China Plain were compared for three treatments during a whole maize growing period from 26 June to 11 October, 2012. Compared with the control treatment (without fertilization, designated as CK), remarkable pulse emissions of N2O, NO and NH3 were observed from the normal fertilization treatment (designated as NP) just after fertilization, whereas only N2O and NH3 pulse emissions were evident from the nitrification inhibitor treatment (designated as ND). The reduction proportions of N2O and NO emissions from the ND treatment compared to those from the NP treatment during the whole maize growing period were 31% and 100%, respectively. A measurable increase of NH3 emission from the ND treatment was found with a cumulative NH3 emission of 3.8 ± 1.2 kg N/ha, which was 1.4 times greater than that from the NP treatment (2.7 ± 0.7 kg N/ha). Copyright © 2015. Published by Elsevier B.V.

  20. Nitrous oxide emission related to ammonia-oxidizing bacteria and mitigation options from N fertilization in a tropical soil

    Science.gov (United States)

    Soares, Johnny R.; Cassman, Noriko A.; Kielak, Anna M.; Pijl, Agata; Carmo, Janaína B.; Lourenço, Kesia S.; Laanbroek, Hendrikus J.; Cantarella, Heitor; Kuramae, Eiko E.

    2016-07-01

    Nitrous oxide (N2O) from nitrogen fertilizers applied to sugarcane has high environmental impact on ethanol production. This study aimed to determine the main microbial processes responsible for the N2O emissions from soil fertilized with different N sources, to identify options to mitigate N2O emissions, and to determine the impacts of the N sources on the soil microbiome. In a field experiment, nitrogen was applied as calcium nitrate, urea, urea with dicyandiamide or 3,4 dimethylpyrazone phosphate nitrification inhibitors (NIs), and urea coated with polymer and sulfur (PSCU). Urea caused the highest N2O emissions (1.7% of N applied) and PSCU did not reduce cumulative N2O emissions compared to urea. NIs reduced N2O emissions (95%) compared to urea and had emissions comparable to those of the control (no N). Similarly, calcium nitrate resulted in very low N2O emissions. Interestingly, N2O emissions were significantly correlated only with bacterial amoA, but not with denitrification gene (nirK, nirS, nosZ) abundances, suggesting that ammonia-oxidizing bacteria, via the nitrification pathway, were the main contributors to N2O emissions. Moreover, the treatments had little effect on microbial composition or diversity. We suggest nitrate-based fertilizers or the addition of NIs in NH4+-N based fertilizers as viable options for reducing N2O emissions in tropical soils and lessening the environmental impact of biofuel produced from sugarcane.

  1. Annual methane and nitrous oxide emissions from rice paddies and inland fish aquaculture wetlands in southeast China

    Science.gov (United States)

    Wu, Shuang; Hu, Zhiqiang; Hu, Tao; Chen, Jie; Yu, Kai; Zou, Jianwen; Liu, Shuwei

    2018-02-01

    Inland aquaculture ponds have been documented as important sources of atmospheric methane (CH4) and nitrous oxide (N2O), while their regional or global source strength remains unclear due to lack of direct flux measurements by covering more typical habitat-specific aquaculture environments. In this study, we compared the CH4 and N2O fluxes from rice paddies and nearby inland fish aquaculture wetlands that were converted from rice paddies in southeast China. Both CH4 and N2O fluxes were positively related to water temperature and sediment dissolved organic carbon, but negatively related to water dissolved oxygen concentration. More robust response of N2O fluxes to water mineral N was observed than to sediment mineral N. Annual CH4 and N2O fluxes from inland fish aquaculture averaged 0.51 mg m-2 h-1 and 54.78 μg m-2 h-1, amounting to 42.31 kg CH4 ha-1 and 2.99 kg N2O-N ha-1, respectively. The conversion of rice paddies to conventional fish aquaculture significantly reduced CH4 and N2O emissions by 23% and 66%, respectively. The emission factor for N2O was estimated to be 0.46% of total N input in the feed or 1.23 g N2O-N kg-1 aquaculture production. The estimate of sustained-flux global warming potential of annual CH4 and N2O emissions and the net economic profit suggested that such conversion of rice paddies to inland fish aquaculture would help to reconcile the dilemma for simultaneously achieving both low climatic impacts and high economic benefits in China. More solid direct field measurements from inland aquaculture are in urgent need to direct the overall budget of national or global CH4 and N2O fluxes.

  2. Tracking nitrous oxide emission processes at a suburban site with semicontinuous, in situ measurements of isotopic composition

    Science.gov (United States)

    Harris, Eliza; Henne, Stephan; Hüglin, Christoph; Zellweger, Christoph; Tuzson, Béla; Ibraim, Erkan; Emmenegger, Lukas; Mohn, Joachim

    2017-02-01

    The isotopic composition of atmospheric nitrous oxide (N2O) was measured semicontinuously, at ˜35 min frequency in intermittent periods of 1-6 days over one and a half years, using preconcentration coupled to a quantum cascade laser spectrometer at the suburban site of Dübendorf, Switzerland. The achieved measurement repeatability was 0.08‰, 0.11‰, and 0.10‰ for δ18O, site preference, and δ15Nbulk respectively, which is better than or equal to standard flask sampling-based isotope ratio mass spectrometry performance. The observed mean diurnal cycle reflected the buildup of N2O from isotopically light sources on an isotopically heavy tropospheric background. The measurements were used to determine the source isotopic composition, which varied significantly compared to chemical and meteorological parameters monitored at the site. FLEXPART-COSMO transport modeling in combination with modified Emissions Database for Global Atmospheric Research inventory emissions was used to model N2O mole fractions at the site. Additionally, isotopic signatures were estimated for different source categories using literature data and used to simulate N2O isotopic composition over the measurement period. The model was able to capture variability in N2O mole fraction well, but simulations of isotopic composition showed little agreement with observations. In particular, measured source isotopic composition exhibited one magnitude larger variability than simulated, clearly indicating that the range of isotopic source signatures estimated from literature significantly underestimates true variability of source signatures. Source δ18O signature was found to be the most sensitive tracer for urban/industry versus agricultural N2O. δ15Nbulk and site preference may provide more insight into microbial and chemical emission processes than partitioning of anthropogenic source categories.

  3. The safety of addition of nitrous oxide to general anaesthesia in at-risk patients having major non-cardiac surgery (ENIGMA-II): a randomised, single-blind trial.

    Science.gov (United States)

    Myles, Paul S; Leslie, Kate; Chan, Matthew T V; Forbes, Andrew; Peyton, Philip J; Paech, Michael J; Beattie, W Scott; Sessler, Daniel I; Devereaux, P J; Silbert, Brendan; Schricker, Thomas; Wallace, Sophie

    2014-10-18

    Nitrous oxide is commonly used in general anaesthesia but concerns exist that it might increase perioperative cardiovascular risk. We aimed to gather evidence to establish whether nitrous oxide affects perioperative cardiovascular risk. We did an international, randomised, assessor-blinded trial in patients aged at least 45 years with known or suspected coronary artery disease having major non-cardiac surgery. Patients were randomly assigned via automated telephone service, stratified by site, to receive a general anaesthetic with or without nitrous oxide. Attending anaesthetists were aware of patients' group assignments, but patients and assessors were not. The primary outcome measure was a composite of death and cardiovascular complications (non-fatal myocardial infarction, stroke, pulmonary embolism, or cardiac arrest) within 30 days of surgery. Our modified intention-to-treat population included all patients randomly assigned to groups and undergoing induction of general anaesthesia for surgery. This trial is registered at ClinicalTrials.gov, number NCT00430989. Of 10,102 eligible patients, we enrolled 7112 patients between May 30, 2008, and Sept 28, 2013. 3543 were assigned to receive nitrous oxide and 3569 were assigned not to receive nitrous oxide. 3483 patients receiving nitrous oxide and 3509 not receiving nitrous oxide were assessed for the primary outcome. The primary outcome occurred in 283 (8%) patients receiving nitrous oxide and in 296 (8%) patients not receiving nitrous oxide (relative risk 0·96, 95% CI 0·83–1·12; p=0·64). Surgical site infection occurred in 321 (9%) patients assigned to nitrous oxide, and in 311 (9%) patients in the no-nitrous oxide group (p=0·61), and severe nausea and vomiting occurred in 506 patients (15%) assigned to nitrous oxide and 378 patients (11%) not assigned to nitrous oxide (pnitrous oxide use in major non-cardiac surgery. Nitrous oxide did not increase the risk of death and cardiovascular complications or

  4. Concomitant administration of nitrous oxide and remifentanil reduces oral tissue blood flow without decreasing blood pressure during sevoflurane anesthesia in rabbits.

    Science.gov (United States)

    Kasahara, Masataka; Ichinohe, Tatsuya; Okamoto, Sota; Okada, Reina; Kanbe, Hiroaki; Matsuura, Nobuyuki

    2015-06-01

    To determine whether continuous administration of nitrous oxide and remifentanil—either alone or together—alters blood flow in oral tissues during sevoflurane anesthesia. Eight male tracheotomized Japanese white rabbits were anesthetized with sevoflurane under mechanical ventilation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), common carotid arterial blood flow (CCBF), tongue mucosal blood flow (TMBF), mandibular bone marrow blood flow (BBF), masseter muscle blood flow (MBF), upper alveolar tissue blood flow (UBF), and lower alveolar tissue blood flow (LBF) were recorded in the absence of all test agents and after administration of the test agents (50 % nitrous oxide, 0.4 μg/kg/min remifentanil, and their combination) for 20 min. Nitrous oxide increased SBP, DBP, MAP, CCBF, BBF, MBF, UBF, and LBF relative to baseline values but did not affect HR or TMBF. Remifentanil decreased all hemodynamic variables except DBP. Combined administration of nitrous oxide and remifentanil recovered SBP, DBP, MAP, and CCBF to baseline levels, but HR and oral tissue blood flow remained lower than control values. Our findings suggest that concomitant administration of nitrous oxide and remifentanil reduces blood flow in oral tissues without decreasing blood pressure during sevoflurane anesthesia in rabbits.

  5. Comparison of oral midazolam with a combination of oral midazolam and nitrous oxide-oxygen inhalation in the effectiveness of dental sedation for young children

    Directory of Open Access Journals (Sweden)

    Al-Zahrani A

    2009-03-01

    Full Text Available Aim: To compare the effectiveness of 0.6 mg/kg oral midazolam sedation alone and a combination of 0.6 mg/kg oral midazolam plus nitrous oxide-oxygen inhalation sedation, in controlling the behavior of uncooperative children during dental treatment. Study Design: The study had a crossover design where the same patient received two different sedation regimens, that is, oral midazolam 0.6 mg/kg and oral midazolam 0.6 mg/kg with nitrous oxide-oxygen inhalation during two dental treatment visits. Materials and Methods: Thirty children (17 males and 13 females were randomly selected for the study, with a mean age of 55.07 (± 9.29 months, ranging from 48 - 72 months. A scoring system suggested by Houpt et al. (1985 was utilized for assessment of the children′s behavior. Results : There was no significant (p > 0.05 difference in the overall behavior assessment between the two sedation regimens, that is, oral midazolam alone and oral midazolam plus nitrous oxide-oxygen. However, the combination of midazolam and nitrous oxide-oxygen showed significantly (p < 0.05 superior results as compared to midazolam alone, in terms of controlling movement and crying during local anesthesia administration and restorative procedures. Conclusion: Compared to oral midazolam alone, a combination of oral midazolam and nitrous oxide inhalation sedation appears to provide more comfort to pediatric dental patients and operators during critical stages of dental treatment.

  6. Nitrous oxide emissions from sugarcane straw left on the soil surface in Brazil

    Science.gov (United States)

    Galdos, M. V.; Cerri, C. E.; Carvalho, J. L.; Cerri, C. C.

    2012-12-01

    In Brazil, the largest exporter of ethanol from sugarcane in the world, burning the dry leaves and tops in order to facilitate the harvest and transportation of the stalks is still a common practice. Burning plant residues causes emissions of greenhouse gases (GHGs) such as CO2, CH4 and N2O, besides the release of charcoal particles into the atmosphere. Due to a combination of pressure from changes in the public opinion and economical reasons, in Brazil sugarcane harvest is changing from a burned into an unburned system. Since manual harvest of sugarcane without burning is not economically feasible, mechanical harvesters have been developed that can take the stalk and leave the residues on the field, forming a mulch, in a system called green cane management. It is expected that 80% of the cane harvested in the main producing regions in Brazil will be harvested without burning by 2014. The conversion from burning sugarcane to green management of sugarcane will have impacts on the biogeochemical cycling of carbon and nitrogen in the plant soil system. The green cane management results in the deposition of large amounts of plant litter on the soil surface after harvest, ranging from 10 to 20 tons per hectare, which impact the whole production process of sugarcane, influencing yields, fertilizer management and application, soil erosion, soil organic matter dynamics as well as greenhouse gas emissions (CO2, N2O, CH4). From a GHG perspective, the conservation of sugarcane residues prevents emissions from the burning process, may promote carbon sequestration in soils and releases nitrogen during the decomposition process replacing the need for, and GHG emissions from, fossil fuel based nitrogen fertilizer sources. Measurements of soil C and N stocks and associated greenhouse gas emissions from the burned and unburned sugarcane systems and in the sugarcane expansion areas are still scarce. Therefore, the main objective of this work was to quantify the nitrous oxide

  7. Effects of lignite application on ammonia and nitrous oxide emissions from cattle pens

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jianlei, E-mail: su@unimelb.edu.au [Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC 3010 (Australia); Bai, Mei [Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC 3010 (Australia); Shen, Jianlin [Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China); Griffith, David W.T. [Department of Chemistry, University of Wollongong, NSW 2522 (Australia); Denmead, Owen T. [Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC 3010 (Australia); Hill, Julian [Ternes Agricultural Consulting Pty Ltd, Upwey, VIC 3158 (Australia); Lam, Shu Kee; Mosier, Arvin R. [Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC 3010 (Australia); Chen, Deli, E-mail: delichen@unimelb.edu.au [Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC 3010 (Australia)

    2016-09-15

    Beef cattle feedlots are a major source of ammonia (NH{sub 3}) emissions from livestock industries. We investigated the effects of lignite surface applications on NH{sub 3} and nitrous oxide (N{sub 2}O) emissions from beef cattle feedlot pens. Two rates of lignite, 3 and 6 kg m{sup −2}, were tested in the treatment pen. No lignite was applied in the control pen. Twenty-four Black Angus steers were fed identical commercial rations in each pen. We measured NH{sub 3} and N{sub 2}O concentrations continuously from 4th Sep to 13th Nov 2014 using Quantum Cascade Laser (QCL) NH{sub 3} analysers and a closed-path Fourier Transform Infrared Spectroscopy analyser (CP-FTIR) in conjunction with the integrated horizontal flux method to calculate NH{sub 3} and N{sub 2}O fluxes. During the feeding period, 16 and 26% of the excreted nitrogen (N) (240 g N head{sup −1} day{sup −1}) was lost via NH{sub 3} volatilization from the control pen, while lignite application decreased NH{sub 3} volatilization to 12 and 18% of the excreted N, for Phase 1 and Phase 2, respectively. Compared to the control pen, lignite application decreased NH{sub 3} emissions by approximately 30%. Nitrous oxide emissions from the cattle pens were small, 0.10 and 0.14 g N{sub 2}O-N head{sup −1} day{sup −1} (< 0.1% of excreted N) for the control pen, for Phase 1 and Phase 2, respectively. Lignite application increased direct N{sub 2}O emissions by 40 and 57%, to 0.14 and 0.22 g N{sub 2}O-N head{sup −1} day{sup −1}, for Phase 1 and Phase 2, respectively. The increase in N{sub 2}O emissions resulting from lignite application was counteracted by the lower indirect N{sub 2}O emission due to decreased NH{sub 3} volatilization. Using 1% as a default emission factor of deposited NH{sub 3} for indirect N{sub 2}O emissions, the application of lignite decreased total N{sub 2}O emissions. - Graphical abstract: Lignite application substantially decreased NH{sub 3} emissions from cattle feedlots and increased

  8. PKQuest: volatile solutes - application to enflurane, nitrous oxide, halothane, methoxyflurane and toluene pharmacokinetics.

    Science.gov (United States)

    Levitt, David G

    2002-08-15

    BACKGROUND: The application of physiologically based pharmacokinetic models (PBPK) to human studies has been limited by the lack of the detailed organ information that is required for this analysis. PKQuest is a new generic PBPK that is designed to avoid this problem by using a set of "standard human" default parameters that are applicable to most solutes. RESULTS: PKQuest is used to model the human pharmacokinetics of the volatile solutes. A "standard human" value for the lipid content of the blood and each organ (klip) was chosen. This set of klip and the oil/water partition coefficient then specifies the organ/blood partition for each organ. Using this approach, the pharmacokinetics of inert volatile solute is completely specified by just 2 parameters: the water/air and oil/water partition coefficients. The model predictions of PKQuest were in good agreement with the experimental data for the inert solutes enflurane and nitrous oxide and the metabolized solutes halothane and toluene. METHODS: The experimental data that was modeled was taken from previous publications. CONCLUSIONS: This approach greatly increases the predictive power of the PBPK. For inert volatile solutes the pharmacokinetics are determined just from the water/air and oil/water partition coefficient. Methoxyflurane cannot be modeled by this PBPK because the arterial and end tidal partial pressures are not equal (as assumed in the PBPK). This inequality results from the "washin-washout" artifact in the large airways that is established for solutes with large water/air partition coefficients.PKQuest and the worked examples are available on the web www.pkquest.com.

  9. Nitrous oxide for pain management during in-office hysteroscopic sterilization: a randomized controlled trial.

    Science.gov (United States)

    Schneider, Emily N; Riley, Regan; Espey, Eve; Mishra, Shiraz I; Singh, Rameet H

    2017-03-01

    To evaluate whether inhaled nitrous oxide with oxygen (N 2 O/O 2 ) is associated with less pain compared to oral sedation for pain management during in-office hysteroscopic sterilization. This double blinded randomized controlled trial enrolled women undergoing in-office hysteroscopic sterilization. All participants received pre-procedure intramuscular ketorolac and a standardized paracervical block. The intervention group also received N 2 O/O 2 via a nasal mask titrated to a maximum 70%:30% mixture by a nurse during the procedure and placebo pills pre-procedure and the active control group received inhaled O 2 during the procedure and 5/325 mg hydrocodone/acetaminophen and 1 mg lorazepam pre-procedure. The primary outcome was maximum procedure pain on a 100 mm Visual Analog Scale (VAS with anchors at 0=no pain and 100=worst imaginable pain) assessed 3-5 min post procedure. Thirty women per treatment arm were required to detect a clinically significant pain difference of 20 mm. Seventy-two women, 36 per study arm, were randomized. Mean age of participants was 34.1±5.7 years and mean BMI was 30.1±6.6kg/m 2 . Mean maximum procedure pain scores were 22.8±27.6 mm and 54.5±32.7 mm for intervention and control groups, respectively (psterilization compared to oral sedation and is an effective pain management option for this procedure. Given its safety and favorable side effect profile, N 2 O/O 2 can be used for pain management for in-office hysteroscopic sterilization and adds a safe, easily administered option to currently available strategies. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Nitrous oxide production from temperate and tropical oyster species in response to nutrient loading

    Science.gov (United States)

    Chan, H.; Garate, M.; Moseman-Valtierra, S.

    2016-02-01

    Anthropogenic pollution, such as nitrogen (N), has the potential to increase greenhouse gas (GHG) emissions in marine ecosystems. Some organisms can be used as important biological indicators for GHG emissions to their environment based on their feeding habits. With large inputs of these anthropogenic pollutants, emissions of nitrous oxide (N2O), a potent GHG, can be potentially increased from temperate invertebrates, though not much is known about tropical invertebrates. Thus, we compared N2O emissions in response to N additions from the temperate oyster species Crassostrea virginica and compared it to a tropical species, Isognomon alatus, found in Puerto Rico. Oysters were exposed to two seawater treatments: (1) no nutrient addition (control) and (2) 100µM ammonium nitrate. Each treatment had 4-5 replicates. Measurements for dissolved N2O and nutrients were taken at the start of the incubation and then at two, four, and five hours by collecting water samples of each tank. Dissolved N2O concentrations were analyzed using gas chromatography. We hypothesized that the N addition treatment would produce more N2O for both Rhode Island and Puerto Rico. We found that there was no significant difference between the control and N enriched treatments for C. virginica over the short timespan, although the N enriched treatment did have a steady trend in increasing in N2O concentration over time. Further analysis is needed for the I. alatus, though we expect an increase in N2O emissions due to warmer water temperatures, which might enhance microbial metabolism and production of N2O. This differs from work previously done in a long-term experiment on C. virginica, which showed that N2O significantly in the N enriched treatment over 28-days. Our study shows that short-term pulses of N may not potentially increase N2O emissions, though further analysis is needed for longer-term exposures.

  11. Spatial and temporal variability of nitrous oxide emissions in a mixed farming landscape of Denmark

    Directory of Open Access Journals (Sweden)

    K. Schelde

    2012-08-01

    Full Text Available Nitrous oxide (N2O emissions from agricultural land are variable at the landscape scale due to variability in land use, management, soil type, and topography. A field experiment was carried out in a typical mixed farming landscape in Denmark, to investigate the main drivers of variations in N2O emissions, measured using static chambers. Measurements were made over a period of 20 months, and sampling was intensified during two weeks in spring 2009 when chambers were installed at ten locations or fields to cover different crops and topography and slurry was applied to three of the fields. N2O emissions during spring 2009 were relatively low, with maximum values below 20 ng N m−2 s−1. This applied to all land use types including winter grain crops, grasslands, meadows, and wetlands. Slurry application to wheat fields resulted in short-lived two-fold increases in emissions. The moderate N2O fluxes and their moderate response to slurry application were attributed to dry soil conditions due to the absence of rain during the four previous weeks. Cumulative annual emissions from two arable fields that were both fertilized with mineral fertilizer and manure were large (17 kg N2O-N ha−1 yr−1 and 5.5 kg N2O-N ha−1 yr−1 during the previous year when soil water conditions were favourable for N2O production during the first month following fertilizer application. Our findings confirm the importance of weather conditions as well as nitrogen management on N2O fluxes.

  12. A review of nitrous oxide mitigation by farm nitrogen management in temperate grassland-based agriculture.

    Science.gov (United States)

    Li, Dejun; Watson, Catherine J; Yan, Ming Jia; Lalor, Stan; Rafique, Rashid; Hyde, Bernard; Lanigan, Gary; Richards, Karl G; Holden, Nicholas M; Humphreys, James

    2013-10-15

    Nitrous oxide (N2O) emission from grassland-based agriculture is an important source of atmospheric N2O. It is hence crucial to explore various solutions including farm nitrogen (N) management to mitigate N2O emissions without sacrificing farm profitability and food supply. This paper reviews major N management practices to lower N2O emission from grassland-based agriculture. Restricted grazing by reducing grazing time is an effective way to decrease N2O emissions from excreta patches. Balancing the protein-to-energy ratios in the diets of ruminants can also decrease N2O emissions from excreta patches. Among the managements of synthetic fertilizer N application, only adjusting fertilizer N rate and slow-released fertilizers are proven to be effective in lowering N2O emissions. Use of bedding materials may increase N2O emissions from animal houses. Manure storage as slurry, manipulating slurry pH to values lower than 6 and storage as solid manure under anaerobic conditions help to reduce N2O emissions during manure storage stage. For manure land application, N2O emissions can be mitigated by reducing manure N inputs to levels that satisfy grass needs. Use of nitrification inhibitors can substantially lower N2O emissions associated with applications of fertilizers and manures and from urine patches. N2O emissions from legume based grasslands are generally lower than fertilizer-based systems. In conclusion, effective measures should be taken at each step during N flow or combined options should be used in order to mitigate N2O emission at the farm level. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. EFFECT OF RICE STRAW AND NITRATE LEVELS IN SOIL SOLUTION ON NITROUS OXIDE EMISSION

    Directory of Open Access Journals (Sweden)

    André Carlos Cruz Copetti

    2015-04-01

    Full Text Available Among the greenhouse gases, nitrous oxide (N2O is considered important, in view of a global warming potential 296 times greater than that of carbon dioxide (CO2 and its dynamics strongly depend on the availability of C and mineral N in the soil. The understanding of the factors that define emissions is essential to develop mitigation strategies. This study evaluated the dynamics of N2O emissions after the application of different rice straw amounts and nitrate levels in soil solution. Pots containing soil treated with sodium nitrate rates (0, 50 and 100 g kg-1 of NO−3-N and rice straw levels (0, 5 and 10 Mg ha-1, i.e., nine treatments, were subjected to anaerobic conditions. The results showed that N2O emissions were increased by the addition of greater NO−3 amounts and reduced by large straw quantities applied to the soil. On the 1st day after flooding (DAF, significantly different N2O emissions were observed between the treatments with and without NO−3 addition, when straw had no significant influence on N2O levels. Emissions peaked on the 4th DAF in the treatments with highest NO−3-N addition. At this moment, straw application negatively affected N2O emissions, probably due to NO−3 immobilization. There were also alterations in other soil electrochemical characteristics, e.g., higher straw levels raised the Fe, Mn and dissolved C contents. These results indicate that a lowering of NO−3 concentration in the soil and the increase of straw incorporation can decrease N2O emissions.

  14. Unexpected nondenitrifier nitrous oxide reductase gene diversity and abundance in soils.

    Science.gov (United States)

    Sanford, Robert A; Wagner, Darlene D; Wu, Qingzhong; Chee-Sanford, Joanne C; Thomas, Sara H; Cruz-García, Claribel; Rodríguez, Gina; Massol-Deyá, Arturo; Krishnani, Kishore K; Ritalahti, Kirsti M; Nissen, Silke; Konstantinidis, Konstantinos T; Löffler, Frank E

    2012-11-27

    Agricultural and industrial practices more than doubled the intrinsic rate of terrestrial N fixation over the past century with drastic consequences, including increased atmospheric nitrous oxide (N(2)O) concentrations. N(2)O is a potent greenhouse gas and contributor to ozone layer destruction, and its release from fixed N is almost entirely controlled by microbial activities. Mitigation of N(2)O emissions to the atmosphere has been attributed exclusively to denitrifiers possessing NosZ, the enzyme system catalyzing N(2)O to N(2) reduction. We demonstrate that diverse microbial taxa possess divergent nos clusters with genes that are related yet evolutionarily distinct from the typical nos genes of denitirifers. nos clusters with atypical nosZ occur in Bacteria and Archaea that denitrify (44% of genomes), do not possess other denitrification genes (56%), or perform dissimilatory nitrate reduction to ammonium (DNRA; (31%). Experiments with the DNRA soil bacterium Anaeromyxobacter dehalogenans demonstrated that the atypical NosZ is an effective N(2)O reductase, and PCR-based surveys suggested that atypical nosZ are abundant in terrestrial environments. Bioinformatic analyses revealed that atypical nos clusters possess distinctive regulatory and functional components (e.g., Sec vs. Tat secretion pathway in typical nos), and that previous nosZ-targeted PCR primers do not capture the atypical nosZ diversity. Collectively, our results suggest that nondenitrifying populations with a broad range of metabolisms and habitats are potentially significant contributors to N(2)O consumption. Apparently, a large, previously unrecognized group of environmental nosZ has not been accounted for, and characterizing their contributions to N(2)O consumption will advance understanding of the ecological controls on N(2)O emissions and lead to refined greenhouse gas flux models.

  15. Microbial Abundances Predict Methane and Nitrous Oxide Fluxes from a Windrow Composting System

    Science.gov (United States)

    Li, Shuqing; Song, Lina; Gao, Xiang; Jin, Yaguo; Liu, Shuwei; Shen, Qirong; Zou, Jianwen

    2017-01-01

    Manure composting is a significant source of atmospheric methane (CH4) and nitrous oxide (N2O) that are two potent greenhouse gases. The CH4 and N2O fluxes are mediated by methanogens and methanotrophs, nitrifying and denitrifying bacteria in composting manure, respectively, while these specific bacterial functional groups may interplay in CH4 and N2O emissions during manure composting. To test the hypothesis that bacterial functional gene abundances regulate greenhouse gas fluxes in windrow composting systems, CH4 and N2O fluxes were simultaneously measured using the chamber method, and molecular techniques were used to quantify the abundances of CH4-related functional genes (mcrA and pmoA genes) and N2O-related functional genes (amoA, narG, nirK, nirS, norB, and nosZ genes). The results indicate that changes in interacting physicochemical parameters in the pile shaped the dynamics of bacterial functional gene abundances. The CH4 and N2O fluxes were correlated with abundances of specific compositional genes in bacterial community. The stepwise regression statistics selected pile temperature, mcrA and NH4+ together as the best predictors for CH4 fluxes, and the model integrating nirK, nosZ with pmoA gene abundances can almost fully explain the dynamics of N2O fluxes over windrow composting. The simulated models were tested against measurements in paddy rice cropping systems, indicating that the models can also be applicable to predicting the response of CH4 and N2O fluxes to elevated atmospheric CO2 concentration and rising temperature. Microbial abundances could be included as indicators in the current carbon and nitrogen biogeochemical models. PMID:28373862

  16. Nitrous Oxide and Ammonia Emissions from Injected and Broadcast-Applied Dairy Slurry.

    Science.gov (United States)

    Duncan, E W; Dell, C J; Kleinman, P J A; Beegle, D B

    2017-01-01

    Trade-offs associated with surface application or injection of manure pose important environmental and agronomic concerns. Manure injection can conserve nitrogen (N) by decreasing ammonia (NH) volatilization. However, the injection band also creates conditions that potentially favor nitrous oxide (NO) production: an abundant organic substrate-promoting microbial activity, anaerobic conditions favoring denitrification, and large local concentrations of N. We assessed differences in NH volatilization and NO emissions with broadcast application versus shallow disk injection of dairy slurry during the 2011 to 2013 growing seasons on a well-drained silt loam that received average manure-N application rates of 180 kg N ha via injection or 200 kg N ha via broadcast. Ammonia emissions were measured using a photoacoustic gas analyzer and chambers, and NO emissions were measured using syringes to draw timed samples from vented chambers with analysis by gas chromatograph. Results point to a 92 to 98% (3.02-11.05 kg NH-N ha) reduction in NH volatilization (for the initial sampling) with injection compared with broadcasting manure but also reveal 84 to 152% (725.9-3187.8 g NO-N ha) greater cumulative NO emissions. Although losses of N via NO emission were at least three orders of magnitude less than NH volatilization, their potential role as a greenhouse gas is of concern. Despite the potential greenhouse gas trade-offs associated with shallow disk injection of manure, decreasing NH volatilization provides a substantial benefit, especially to farmers who are trying to conserve N and improve the N/P ratio of soil-applied manure. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  17. Modulation of Functional EEG Networks by the NMDA Antagonist Nitrous Oxide

    Science.gov (United States)

    Kuhlmann, Levin; Foster, Brett L.; Liley, David T. J.

    2013-01-01

    Parietal networks are hypothesised to play a central role in the cortical information synthesis that supports conscious experience and behavior. Significant reductions in parietal level functional connectivity have been shown to occur during general anesthesia with propofol and a range of other GABAergic general anesthetic agents. Using two analysis approaches (1) a graph theoretic analysis based on surrogate-corrected zero-lag correlations of scalp EEG, and (2) a global coherence analysis based on the EEG cross-spectrum, we reveal that sedation with the NMDA receptor antagonist nitrous oxide (N2O), an agent that has quite different electroencephalographic effects compared to the inductive general anesthetics, also causes significant alterations in parietal level functional networks, as well as changes in full brain and frontal level networks. A total of 20 subjects underwent N2O inhalation at either 20%, 40% or 60% peak N2O/O2 gas concentration levels. N2O-induced reductions in parietal network level functional connectivity (on the order of 50%) were exclusively detected by utilising a surface Laplacian derivation, suggesting that superficial, smaller spatial scale, cortical networks were most affected. In contrast reductions in frontal network functional connectivity were optimally discriminated using a common-reference derivation (reductions on the order of 10%), indicating that the NMDA antagonist N2O induces spatially coherent and widespread perturbations in frontal activity. Our findings not only give important weight to the idea of agent invariant final network changes underlying drug-induced reductions in consciousness, but also provide significant impetus for the application and development of multiscale functional analyses to systematically characterise the network level cortical effects of NMDA receptor related hypofunction. Future work at the source space level will be needed to verify the consistency between cortical network changes seen at the source

  18. Modulation of functional EEG networks by the NMDA antagonist nitrous oxide.

    Directory of Open Access Journals (Sweden)

    Levin Kuhlmann

    Full Text Available Parietal networks are hypothesised to play a central role in the cortical information synthesis that supports conscious experience and behavior. Significant reductions in parietal level functional connectivity have been shown to occur during general anesthesia with propofol and a range of other GABAergic general anesthetic agents. Using two analysis approaches (1 a graph theoretic analysis based on surrogate-corrected zero-lag correlations of scalp EEG, and (2 a global coherence analysis based on the EEG cross-spectrum, we reveal that sedation with the NMDA receptor antagonist nitrous oxide (N2O, an agent that has quite different electroencephalographic effects compared to the inductive general anesthetics, also causes significant alterations in parietal level functional networks, as well as changes in full brain and frontal level networks. A total of 20 subjects underwent N2O inhalation at either 20%, 40% or 60% peak N2O/O2 gas concentration levels. N2O-induced reductions in parietal network level functional connectivity (on the order of 50% were exclusively detected by utilising a surface Laplacian derivation, suggesting that superficial, smaller spatial scale, cortical networks were most affected. In contrast reductions in frontal network functional connectivity were optimally discriminated using a common-reference derivation (reductions on the order of 10%, indicating that the NMDA antagonist N2O induces spatially coherent and widespread perturbations in frontal activity. Our findings not only give important weight to the idea of agent invariant final network changes underlying drug-induced reductions in consciousness, but also provide significant impetus for the application and development of multiscale functional analyses to systematically characterise the network level cortical effects of NMDA receptor related hypofunction. Future work at the source space level will be needed to verify the consistency between cortical network changes seen

  19. Emissions of ammonia, nitrous oxide and methane from cattle manure heaps: effect of compaction and covering

    Science.gov (United States)

    Chadwick, D. R.

    The effect of compaction and covering during storage of beef cattle ( Bos taurus) farmyard manure (FYM) on ammonia (NH 3), nitrous oxide (N 2O) and methane (CH 4) emissions was determined. Gaseous emission measurements were made over three separate storage periods of between 90 and 109 days. The effect of the different storage treatments on manure chemical composition was also determined. Compaction was carried out as the manure was put into store and the compacted manures covered with plastic sheeting. Compaction and covering significantly reduced NH 3 emissions from manure by over 90% during the first summer storage period (P<0.05). Over the subsequent storage periods NH 3 emissions from the FYM were small and unaffected by storage treatment. However, during the second storage period heavy and persistent rainfall during heap establishment and the following week appeared to reduce NH 3 emissions markedly. The low ammonium-N content of the FYM in the third storage period may have reduced the risk of NH 3 emission and reduced the relative effect of the compaction/covering treatment. Compaction and covering also significantly reduced N 2O emissions from cattle FYM (P<0.05) by ca. 30% during the first storage period. Subsequent N 2O emissions were unaffected by treatment. Methane emissions from cattle FYM were unaffected by treatment over the first storage period and were decreased by compaction in the second storage period yet was increased by compaction during the third storage period. It would appear that compacting and covering manure heaps does have the potential to reduce emissions of both NH 3 and N 2O when the manure contains relatively high ammonium-N contents. Additional benefits are that N and K are retained in the manure heap for agronomic benefit.

  20. Effect of topography on nitrous oxide emissions from winter wheat fields in Central France

    Energy Technology Data Exchange (ETDEWEB)

    Gu Jiangxin, E-mail: Jiangxin.Gu@orleans.inra.fr [INRA, UR 0272 Science du sol, Centre de recherche d' Orleans, CS 40001 Ardon, 45075 Orleans Cedex 2 (France); Nicoullaud, Bernard [INRA, UR 0272 Science du sol, Centre de recherche d' Orleans, CS 40001 Ardon, 45075 Orleans Cedex 2 (France); Rochette, Philippe [Agriculture and Agri-Food Canada, 2560 Hochelaga Blvd, Quebec, QC G1V 2J3 (Canada); Pennock, Daniel J. [Department of Soil Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, Saskatchewan S7N 5A8 (Canada); Henault, Catherine [INRA, UR 0272 Science du sol, Centre de recherche d' Orleans, CS 40001 Ardon, 45075 Orleans Cedex 2 (France); Cellier, Pierre [UMR Environnement et Grandes Cultures, INRA-AgroParisTech, 78850 Thiverval-Grignon (France); Richard, Guy [INRA, UR 0272 Science du sol, Centre de recherche d' Orleans, CS 40001 Ardon, 45075 Orleans Cedex 2 (France)

    2011-11-15

    We assessed nitrous oxide (N{sub 2}O) emissions at shoulder and foot-slope positions along three sloping sites (1.6-2.1%) to identify the factors controlling the spatial variations in emissions. The three sites received same amounts of total nitrogen (N) input at 170 kg N ha{sup -1}. Results showed that landscape positions had a significant, but not consistent effect on N{sub 2}O fluxes with larger emission in the foot-slope at only one of the three sites. The effect of soil inorganic N (NH{sub 4}{sup +} + NO{sub 3}{sup -}) contents on N{sub 2}O fluxes (r{sup 2} = 0.55, p < 0.001) was influenced by water-filled pore space (WFPS). Soil N{sub 2}O fluxes were related to inorganic N at WFPS > 60% (r{sup 2} = 0.81, p < 0.001), and NH{sub 4}{sup +} contents at WFPS < 60% (r{sup 2} = 0.40, p < 0.01), respectively. Differences in WFPS between shoulder and foot-slope correlated linearly with differences in N{sub 2}O fluxes (r{sup 2} = 0.45, p < 0.001). We conclude that spatial variations in N{sub 2}O emission were regulated by the influence of hydrological processes on soil aeration intensity. - Highlights: > Soil inorganic N content was the major factor controlling N{sub 2}O emission. > Soil water content influenced the effect of soil inorganic N content on N{sub 2}O emission. > The position-by-site interactions affected the cumulative fluxes significantly. - Spatial variations in N{sub 2}O fluxes were in part the result of variations in soil water content.

  1. Isotopic evidence for nitrous oxide production pathways in a partial nitritation-anammox reactor.

    Science.gov (United States)

    Harris, Eliza; Joss, Adriano; Emmenegger, Lukas; Kipf, Marco; Wolf, Benjamin; Mohn, Joachim; Wunderlin, Pascal

    2015-10-15

    Nitrous oxide (N2O) production pathways in a single stage, continuously fed partial nitritation-anammox reactor were investigated using online isotopic analysis of offgas N2O with quantum cascade laser absorption spectroscopy (QCLAS). N2O emissions increased when reactor operating conditions were not optimal, for example, high dissolved oxygen concentration. SP measurements indicated that the increase in N2O was due to enhanced nitrifier denitrification, generally related to nitrite build-up in the reactor. The results of this study confirm that process control via online N2O monitoring is an ideal method to detect imbalances in reactor operation and regulate aeration, to ensure optimal reactor conditions and minimise N2O emissions. Under normal operating conditions, the N2O isotopic site preference (SP) was much higher than expected - up to 40‰ - which could not be explained within the current understanding of N2O production pathways. Various targeted experiments were conducted to investigate the characteristics of N2O formation in the reactor. The high SP measurements during both normal operating and experimental conditions could potentially be explained by a number of hypotheses: i) unexpectedly strong heterotrophic N2O reduction, ii) unknown inorganic or anammox-associated N2O production pathway, iii) previous underestimation of SP fractionation during N2O production from NH2OH, or strong variations in SP from this pathway depending on reactor conditions. The second hypothesis - an unknown or incompletely characterised production pathway - was most consistent with results, however the other possibilities cannot be discounted. Further experiments are needed to distinguish between these hypotheses and fully resolve N2O production pathways in PN-anammox systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. PKQuest: volatile solutes – application to enflurane, nitrous oxide, halothane, methoxyflurane and toluene pharmacokinetics

    Directory of Open Access Journals (Sweden)

    Levitt David G

    2002-08-01

    Full Text Available Abstract Background The application of physiologically based pharmacokinetic models (PBPK to human studies has been limited by the lack of the detailed organ information that is required for this analysis. PKQuest is a new generic PBPK that is designed to avoid this problem by using a set of "standard human" default parameters that are applicable to most solutes. Results PKQuest is used to model the human pharmacokinetics of the volatile solutes. A "standard human" value for the lipid content of the blood and each organ (klip was chosen. This set of klip and the oil/water partition coefficient then specifies the organ/blood partition for each organ. Using this approach, the pharmacokinetics of inert volatile solute is completely specified by just 2 parameters: the water/air and oil/water partition coefficients. The model predictions of PKQuest were in good agreement with the experimental data for the inert solutes enflurane and nitrous oxide and the metabolized solutes halothane and toluene. Methods The experimental data that was modeled was taken from previous publications. Conclusions This approach greatly increases the predictive power of the PBPK. For inert volatile solutes the pharmacokinetics are determined just from the water/air and oil/water partition coefficient. Methoxyflurane cannot be modeled by this PBPK because the arterial and end tidal partial pressures are not equal (as assumed in the PBPK. This inequality results from the "washin-washout" artifact in the large airways that is established for solutes with large water/air partition coefficients. PKQuest and the worked examples are available on the web http://www.pkquest.com.

  3. The influence of solid retention time on IFAS-MBR systems: Assessment of nitrous oxide emission.

    Science.gov (United States)

    Mannina, Giorgio; Capodici, Marco; Cosenza, Alida; Laudicina, Vito Armando; Di Trapani, Daniele

    2017-12-01

    The aim of the present study was to investigate the nitrous oxide (N2O) emissions from a moving bed based Integrated Fixed Film Activated Sludge (IFAS) - membrane bioreactor (MBR) pilot plant, designed according to the University of Cape Town (UCT) layout. The experimental campaign had a duration of 110 days and was characterized by three different sludge retention time (SRT) values (∞, 30 d and 15 d). Results highlighted that N2O concentrations decreased when the biofilm concentrations increased within the aerobic reactor. Results have shown an increase of N2O with the decrease of SRT. Specifically, an increase of N2O-N emission factor occurred with the decrease of the SRT (0.13%, 0.21% and 0.76% of influent nitrogen for SRT = ∞, SRT = 30 d and SRT = 15 d, respectively). Moreover, the MBR tank resulted the key emission source (up to 70% of the total N2O emission during SRT = ∞ period) whereas the highest N2O production occurred in the anoxic reactor. Moreover, N2O concentrations measured in the permeate flow were not negligible, thus highlighting its potential detrimental contribution for the receiving water body. The role of each plant reactor as N2O-N producer/consumer varies with the SRT variation, indeed the aerobic reactor was a N2O consumer at SRT = ∞ and a producer at SRT = 30 d. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Nitrous oxide emissions from soils: how well do we understand the processes and their controls?

    Science.gov (United States)

    Butterbach-Bahl, Klaus; Baggs, Elizabeth M.; Dannenmann, Michael; Kiese, Ralf; Zechmeister-Boltenstern, Sophie

    2013-01-01

    Although it is well established that soils are the dominating source for atmospheric nitrous oxide (N2O), we are still struggling to fully understand the complexity of the underlying microbial production and consumption processes and the links to biotic (e.g. inter- and intraspecies competition, food webs, plant–microbe interaction) and abiotic (e.g. soil climate, physics and chemistry) factors. Recent work shows that a better understanding of the composition and diversity of the microbial community across a variety of soils in different climates and under different land use, as well as plant–microbe interactions in the rhizosphere, may provide a key to better understand the variability of N2O fluxes at the soil–atmosphere interface. Moreover, recent insights into the regulation of the reduction of N2O to dinitrogen (N2) have increased our understanding of N2O exchange. This improved process understanding, building on the increased use of isotope tracing techniques and metagenomics, needs to go along with improvements in measurement techniques for N2O (and N2) emission in order to obtain robust field and laboratory datasets for different ecosystem types. Advances in both fields are currently used to improve process descriptions in biogeochemical models, which may eventually be used not only to test our current process understanding from the microsite to the field level, but also used as tools for up-scaling emissions to landscapes and regions and to explore feedbacks of soil N2O emissions to changes in environmental conditions, land management and land use. PMID:23713120

  5. From the ground up: global nitrous oxide sources are constrained by stable isotope values.

    Directory of Open Access Journals (Sweden)

    David M Snider

    Full Text Available Rising concentrations of nitrous oxide (N2O in the atmosphere are causing widespread concern because this trace gas plays a key role in the destruction of stratospheric ozone and it is a strong greenhouse gas. The successful mitigation of N2O emissions requires a solid understanding of the relative importance of all N2O sources and sinks. Stable isotope ratio measurements (δ15N-N2O and δ18O-N2O, including the intramolecular distribution of 15N (site preference, are one way to track different sources if they are isotopically distinct. 'Top-down' isotope mass-balance studies have had limited success balancing the global N2O budget thus far because the isotopic signatures of soil, freshwater, and marine sources are poorly constrained and a comprehensive analysis of global N2O stable isotope measurements has not been done. Here we used a robust analysis of all available in situ measurements to define key global N2O sources. We showed that the marine source is isotopically distinct from soil and freshwater N2O (the continental source. Further, the global average source (sum of all natural and anthropogenic sources is largely controlled by soils and freshwaters. These findings substantiate past modelling studies that relied on several assumptions about the global N2O cycle. Finally, a two-box-model and a Bayesian isotope mixing model revealed marine and continental N2O sources have relative contributions of 24-26% and 74-76% to the total, respectively. Further, the Bayesian modeling exercise indicated the N2O flux from freshwaters may be much larger than currently thought.

  6. Effect of nitrous oxide on fentanyl consumption in burned patients undergoing dressing change.

    Science.gov (United States)

    do Vale, Arthur Halley Barbosa; Videira, Rogério Luiz da Rocha; Gomez, David Souza; Carmona, Maria José Carvalho; Tsuchie, Sara Yume; Flório, Cláudia; Vane, Matheus Fachini; Posso, Irimar de Paula

    2016-01-01

    Thermal injuries and injured areas management are important causes of pain in burned patients, requiring that these patients are constantly undergoing general anesthesia for dressing change. Nitrous oxide (N2O) has analgesic and sedative properties; it is easy to use and widely available. Thus, the aim of this study was to evaluate the analgesic effect of N2O combined with fentanyl in burned patients during dressing change. After approval by the institutional Ethics Committee, 15 adult burned patients requiring daily dressing change were evaluated. Patient analgesia was controlled with fentanyl 0.0005% administered by intravenous pump infusion on-demand. Randomly, in one of the days a mixture of 65% N2O in oxygen (O2) was associated via mask, with a flow of 10 L/min (N2O group) and on the other day only O2 under the same flow (control group). No significant pain reduction was seen in N2O group compared to control group. VAS score before dressing change was 4.07 and 3.4, respectively, in N2O and control groups. Regarding pain at the end of the dressing, patients in N2O group reported pain severity of 2.8; while the control group reported 2.87. There was no significant difference in fentanyl consumption in both groups. The association of N2O was not effective in reducing opioid consumption during dressing changes. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

  7. Historical mining of soil nitrogen was a likely source of atmospheric nitrous oxide

    Science.gov (United States)

    Davidson, E. A.

    2009-12-01

    Prior to the advent of use of synthetic nitrogen (N) fertilizers, agricultural expansion was often followed by depletion of soil carbon and N stocks. While the mining of soil N permits a period of productive agriculture, it may also result in transfers of soil N to groundwater, surface water, and the atmosphere. Atmospheric nitrous oxide (N2O) concentrations have been increasing since the industrial revolution and currently account for 6% of total anthropogenic radiative forcing. Microbial production in soils is the dominant N2O source. The use of synthetic N fertilizers alone cannot account for the historical trends of atmospheric concentrations of N2O, because the increase in atmospheric N2O began well before N fertilizers were widely used. Here, I analyze atmospheric concentrations, industrial sources of N2O, and fertilizer and manure production since 1860. Prior to 1960, agricultural expansion, including livestock production, appears to have caused globally significant mining of soil N, fuelling a steady increase in atmospheric N2O. Post 1960, the rate of the increase rose, due to accelerating use of synthetic N fertilizers. Using a regression model, I show that 2% of manure N and 2.5% of fertilizer N were converted to N2O between 1860 and 2005; these percentage contributions explain the entire pattern of increasing N2O concentrations over this period. Consideration of processes that re-concentrate soil N, such as manure production by livestock, improved hind-casting of N2O emissions. Any process in the past, present, or future that causes either accumulation or depletion of N reservoirs in soils or sediments could affect N2O emissions. As animal protein consumption in human diets increases globally, management of manure will be an important component of future mitigation efforts to reduce anthropogenic N2O sources.

  8. Potential denitrification and nitrous oxide production in the sediments of the Seine River Drainage Network (France).

    Science.gov (United States)

    Garnier, Josette A; Mounier, Emmanuelle M; Laverman, Anniet M; Billen, Gilles F

    2010-01-01

    To investigate bottom sediment denitrification at the scale of the Seine drainage network, a semi-potential denitrification assay was used in which river sediments (and riparian soils) were incubated for a few hours under anaerobic conditions with non limiting nitrate concentrations. This method allowed the nitrous oxide (N(2)O) concentration in the headspace, as well as the nitrate, nitrite, and ammonium concentrations to be determined during incubation. The rates at which nitrate decreased and N(2)O increased were then used to assess the potential denitrification activity and associated N(2)O production in the Seine River Basin. We observed a longitudinal pattern characterized by a significant increase of the potential rate of denitrification from upstream sectors to large downstream rivers (orders 7-8), from approximately 3.3 to 9.1 microg NO(3)(-)-N g(-1) h(-1), respectively, while the N(2)O production rates was the highest both in headwaters and in large order rivers (0.14 and 0.09 N(2)O-N g(-1) h(-1), respectively) and significantly lower in the intermediate sectors (0.01 and 0.03 N(2)O-N g(-1) h(-1)). Consequently, the ratio N(2)O production:NO(3) reduction was found to reach 5% in headstreams, whereas it averaged 1.2% in the rest of the drainage network, an intermediate percentage being found for the riparian soils. Finally, the ignition loss of sediments, together with other redundant variables (particulate organic carbon content: g C 100 g(-1) dry weight [dw], moisture: g water 100 g(-1) dw, sediment size <50 mum: g material size <50 mum 100 g(-1) dw) were found to control these activities. However, the biodegradability of organic matter must be measured to better understand the factor controlling denitrification and its associated N(2)O production.

  9. Nitrous oxide emissions are enhanced in a warmer and wetter world

    Science.gov (United States)

    Griffis, Timothy J.; Chen, Zichong; Baker, John M.; Wood, Jeffrey D.; Millet, Dylan B.; Lee, Xuhui; Venterea, Rodney T.; Turner, Peter A.

    2017-11-01

    Nitrous oxide (N2O) has a global warming potential that is 300 times that of carbon dioxide on a 100-y timescale, and is of major importance for stratospheric ozone depletion. The climate sensitivity of N2O emissions is poorly known, which makes it difficult to project how changing fertilizer use and climate will impact radiative forcing and the ozone layer. Analysis of 6 y of hourly N2O mixing ratios from a very tall tower within the US Corn Belt—one of the most intensive agricultural regions of the world—combined with inverse modeling, shows large interannual variability in N2O emissions (316 Gg N2O-Nṡy‑1 to 585 Gg N2O-Nṡy‑1). This implies that the regional emission factor is highly sensitive to climate. In the warmest year and spring (2012) of the observational period, the emission factor was 7.5%, nearly double that of previous reports. Indirect emissions associated with runoff and leaching dominated the interannual variability of total emissions. Under current trends in climate and anthropogenic N use, we project a strong positive feedback to warmer and wetter conditions and unabated growth of regional N2O emissions that will exceed 600 Gg N2O-Nṡy‑1, on average, by 2050. This increasing emission trend in the US Corn Belt may represent a harbinger of intensifying N2O emissions from other agricultural regions. Such feedbacks will pose a major challenge to the Paris Agreement, which requires large N2O emission mitigation efforts to achieve its goals.

  10. Humphry Davy, nitrous oxide, the Pneumatic Institution, and the Royal Institution.

    Science.gov (United States)

    West, John B

    2014-11-01

    Humphry Davy (1778-1829) has an interesting place in the history of respiratory gases because the Pneumatic Institution in which he did much of his early work signaled the end of an era of discovery. The previous 40 years had seen essentially all of the important respiratory gases described, and the Institution was formed to exploit their possible value in medical treatment. Davy himself is well known for producing nitrous oxide and demonstrating that its inhalation could cause euphoria and heightened imagination. His thinking influenced the poets Samuel Taylor Coleridge and William Wordsworth, and perhaps we can claim that our discipline colored the poetry of the Romantic Movement. Davy was also the first person to measure the residual volume of the lung. The Pneumatic Institution was the brainchild of Thomas Beddoes, who had trained in Edinburgh under Joseph Black, who discovered carbon dioxide. Later Davy moved to the Royal Institution in London formed, in part, to diffuse the knowledge of scientific discoveries to the general public. Davy was a brilliant lecturer and developed an enthusiastic following. In addition he exploited the newly described electric battery to discover several new elements. He also invented the safety lamp in response to a series of devastating explosions in coal mines. Ultimately Davy became president of the Royal Society, a remarkable honor for somebody with such humble origins. Another of his important contributions was to introduce Michael Faraday (1791-1867) to science. Faraday became one of the most illustrious British scientists of all time. Copyright © 2014 the American Physiological Society.

  11. Nitrous Oxide Emissions from a Golf Course Fairway and Rough after Application of Different Nitrogen Fertilizers.

    Science.gov (United States)

    Gillette, Katrina L; Qian, Yaling; Follett, Ronald F; Del Grosso, Stephen

    2016-09-01

    Few studies have quantified nitrous oxide (NO) emissions from intensively managed turfgrass systems on golf courses. Fertilizer treatments consisting of urea with inhibitors of nitrification and urease (INU), polymer-coated urea (PCU), and uncoated balanced methylene urea (BMU) chain, which use different mechanisms to control the release of N substrate, were applied to a golf course fairway and rough three times during the 2011 growing season at a rate of 50 kg N ha per application. The vented chamber method was used to measure turf-soil-atmospheric NO exchange. Cumulative emissions from fairway INU, PCU, and BMU treatments totaled 6.5, 1.9, and 7.6 kg NO-N ha yr, representing a 4.02, 1.25, and 4.75% loss of total N applied, respectively. Summer INU and BMU fertilization to the fairway produced the greatest NO fluxes. Rapid fluxes during the summer were likely related to low physiological activity in cool-season turfgrass and to warm, wet soil conditions that increased denitrification rates. However, PCU applied to the fairway was more resistant to NO losses than other fertilizer treatments. Fertilizer treatments applied to the rough had cumulative emissions of 2.4, 1.50, and 1.49 kg NO-N ha yr from INU, PCU, and BMU treatments, corresponding to a 1.21, 0.62, and 0.61% loss of total N applied, respectively. The lower NO emission on roughs was likely associated with greater carbon pools, lower soil moisture, and lower temperatures. This study supports the effectiveness of PCU to reduce NO emission from cool-season turfgrass fairways when soil conditions favored denitrification during warm periods. Applying INU and BMU when soil was cool and dry was effective in moderating NO losses. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  12. Nitrous oxide persistently alleviates pain hypersensitivity in neuropathic rats: A dose-dependent effect

    Science.gov (United States)

    Ben Boujema, Meric; Laboureyras, Emilie; Pype, Jan; Bessière, Baptiste; Simonnet, Guy

    2015-01-01

    BACKGROUND: Despite numerous pharmacological approaches, there are no common analgesic drugs that produce meaningful relief for the majority of patients with neuropathic pain. Although nitrous oxide (N2O) is a weak analgesic that acts via opioid-dependent mechanisms, it is also an antagonist of the N-methyl-D-aspartate receptor (NMDAR). The NMDAR plays a critical role in the development of pain sensitization induced by nerve injury. OBJECTIVE: Using the chronic constriction injury of the sciatic nerve in male rats as a preclinical model of neuropathic pain, the first aim of the present study was to evaluate the lowest N2O concentration and the shortest time of N2O postinjury exposure that would produce persistent relief of neuropathic pain. The second aim was to compare the effects of N2O with gabapentin, a reference drug used in human neuropathic pain relief. METHODS: Changes in the nociceptive threshold were evaluated using the paw pressure vocalization test in rats. RESULTS: Among the various N2O concentrations tested, which ranged from 25% to 50%, only 50% N2O single exposure for 1 h 15 min induced a persistent (minimum of three weeks) and significant (60%) reduction in pain hypersensitivity. A single gabapentin dose (75 mg/kg to 300 mg/kg, intraperitoneally) induced an acute (1 h to 1 h 30 min) dose-dependent effect, but not a persistent effect such as that observed with N2O. CONCLUSIONS: These preclinical results suggest that N2O is advantageous for long-lasting neuropathic pain relief after sciatic nerve injury compared with other drugs used in humans such as gabapentinoids or NMDAR antagonists. The present preclinical study provides a rationale for developing comparative clinical studies. PMID:26371891

  13. Simultaneous detection of atmospheric nitrous oxide and carbon monoxide using a quantum cascade laser

    Science.gov (United States)

    Khan, Amir; Sun, Kang; Miller, David J.; Zondlo, Mark A.

    2011-06-01

    We describe a non-intrusive, open-path, fast-response compact sensor for simultaneous measurements of nitrous-oxide (N2O) and carbon-monoxide (CO) primarily designed for UAV applications. N2O is the third most important anthropogenic greenhouse gas, but the spatial and temporal distributions of N2O emissions are poorly quantified. On the other hand, CO is an important tracer to distinguish between fossil fuel and biogenic sources. We use a 4.5 micron thermoelectrically-cooled, distributed feedback, continuous wave quantum cascade laser as a mid-infrared radiation source to scan CO and N2O transitions centered at 4538.9 nm and 4539.8 nm respectively. Detection was achieved by a thermo-electrically (TE) cooled 5 micron Indium-Phosphide (InSb) infrared detector. For the first time in this application, a compact cylindrical cell with a pattern configuration to minimize the sensor size with a pathlength of 10 meters (2.54 cm radius mirrors, 25 cm basepath). Wavelength modulation spectroscopy was employed to achieve high sensitivity detection. The detection limit of 10-5 fractional absorbance was achieved at a 10 sec. averaging time. This is equivalent to less than 1 ppbv of N2O and 2 ppbv of CO out of 320 ppbv and 200 ppbv ambient levels respectively. In summary we report a cryogen-free, consumable-free sensor that can operate with 10s W of electrical power and packaged in a small shoe-box size which is ideal for UAV or airborne applications.

  14. Nitrous oxide emissions from a peatbog after 13 years of experimental nitrogen deposition

    Science.gov (United States)

    Leeson, Sarah R.; Levy, Peter E.; van Dijk, Netty; Drewer, Julia; Robinson, Sophie; Jones, Matthew R.; Kentisbeer, John; Washbourne, Ian; Sutton, Mark A.; Sheppard, Lucy J.

    2017-12-01

    Nitrogen deposition was experimentally increased on a Scottish peatbog over a period of 13 years (2002-2015). Nitrogen was applied in three forms, NH3 gas, NH4Cl solution, and NaNO3 solution, at rates ranging from 8 (ambient) to 64 kg N ha-1 yr-1, and higher near the NH3 fumigation source. An automated system was used to apply the nitrogen, such that the deposition was realistic in terms of rates and high frequency of deposition events. We measured the response of nitrous oxide (N2O) flux to the increased nitrogen input. Prior expectations, based on the IPCC default emission factor, were that 1 % of the added nitrogen would be emitted as N2O. In the plots treated with NH4+ and NO3- solution, no response was seen, and there was a tendency for N2O fluxes to be reduced by additional nitrogen, though this was not significant. Areas subjected to high NH3 emitted more N2O than expected, up to 8.5 % of the added nitrogen. Differences in the response are related to the impact of the nitrogen treatments on the vegetation. In the NH4+ and NO3- treatments, all the additional nitrogen is effectively immobilised in the vegetation and top 10 cm of peat. In the NH3 treatment, much of the vegetation was killed off by high doses of NH3, and the nitrogen was presumably more available to denitrifying bacteria. The design of the wet and dry experimental treatments meant that they differed in statistical power, and we are less likely to detect an effect of the NH4+ and NO3- treatments, though they avoid issues of pseudo-replication.

  15. Impact of Cover Cropping and Landscape Positions on Nitrous Oxide Emissions in Northeastern Agroecosystems

    Science.gov (United States)

    Han, Z.; Walter, M. T.; Drinkwater, L. E.

    2015-12-01

    Studies investigating agricultural nitrous oxide (N2O) emissions tend to rely on plot-scale experiments. However, to understand the impacts of agricultural practices at a larger scale, it is essential to consider the variability of landscape characteristics along with management treatments. This study compared N2O emissions from a fertilizer-based, conventionally managed farm and an organically managed farm that uses legume cover crops as a primary nutrient source. The objective of the study was to assess how management regimes and slope positions interact to impact N2O emissions and soil characteristics. The field experiment was conducted in two adjacent grain farms in upstate New York that both have been under consistent management for 20 years. In the organic farm, red clover was frost-seeded into a winter grain (spelt), and then incorporated in the spring as a nutrient source for the subsequent corn plants. In contrast, the conventionally managed farm used inorganic fertilizer as the nutrient source. Gas measurement was conducted at two landscape positions at both farms: 1) shoulder and 2) toeslope positions. Comparable N2O emissions were found in the clover-corn phase in the organic site and the bare fallow-corn phase in the conventional site. The spelt-corn phase in the organic farm had the lowest N2O emissions. Soil nitrate concentration was the best predictor for seasonal average N2O emissions. The impact of landscape position on N2O emissions was only found in the conventional site, which was driven by higher denitrfication at toeslopes. In the organic farm, such effect was confounded by higher clover biomass at shoulder slopes. Our study shows that the impact of landscape characteristics on N2O emissions could differ across sites based on the complex interplay between environmental conditions and management.

  16. Nitrous oxide and methane fluxes in six different land use systems in the Peruvian Amazon

    Science.gov (United States)

    Palm, C. A.; Alegre, J. C.; Arevalo, L.; Mutuo, P. K.; Mosier, A. R.; Coe, R.

    2002-12-01

    The contribution of different land-use systems in the humid tropics to increasing atmospheric trace gases has focused on forests, pastures, and crops with few measurements from managed, tree-based systems that dominate much of the landscape. This study from the Peruvian Amazon includes monthly nitrous oxide and methane fluxes from two cropping systems, three tree-based systems, and a 23-year secondary forest control. Average N2O fluxes from the cropping systems were two to three times higher than the secondary forest control (9.1 μg N m-2 h-1), while those of the tree-based systems were similar to the secondary forest. Increased fluxes in the cropping systems were attributed to N fertilization, while fluxes from the tree-based systems were related to litterfall N. Average CH4 consumption was reduced by up to half that of the secondary forest (-30.0 μg C m-2 h-1) in the tree-based and low-input cropping systems. There was net CH4 production in the high-input cropping system. This switch to net production was a result of increased bulk density and increased soil respiration resulting in anaerobic conditions. Reduced rates of N2O emissions, similar CH4 consumption, and high C sequestration rates in these tree-based systems compared with mature forests, coupled with the large area of these systems in the humid tropics, may partially offset the past effects of deforestation on increased atmospheric trace gas concentrations. In contrast, cropping systems with higher N2O emissions, substantially reduced CH4 consumption or even net CH4 emissions, and little C sequestration exacerbate those effects.

  17. Stable isotopic indicators of nitrous oxide and methane sources in Los Angeles, California

    Science.gov (United States)

    Townsend-Small, A.; Pataki, D.; Tyler, S.; Trumbore, S.

    2008-12-01

    As urbanization increasingly encroaches upon agricultural landscapes, there are greater potential sources of greenhouse gases and other atmospheric contaminants. Measurements of the isotopic composition of trace gases have the potential to distinguish between pollutant sources and quantify the proportional contribution of agricultural activities to the total atmospheric pool. In this study, we are measuring the isotopic composition of greenhouse gases N2O and CH4 emitted from cropland, animal feeding operations, and urban activities in the South Coast Air Basin in southern California. The ultimate goal of our project is to utilize atmospheric measurements of the isotopic composition of N2O and CH4 combined with studies of source signatures to determine the proportional contributions of cropland, animal operations, and urban sources of greenhouse gases to the atmosphere. Measurements of the δ13C of methane show excellent separation between urban sources, such as vehicle emissions, power plants, oil refineries, landfills, and sewage treatment plants and agricultural sources like cows, biogas, and cattle feedlots. For nitrous oxide, soil N2O sources showed good separation from wastewater treatment facilities using δ15N and δ18O. Within soil N2O sources, the isotopic composition of N2O from cropland soils was similar to N2O emissions from urban turfgrass. These data indicate that nitrification may be as important a source of N2O as denitrification in urban soils. We are also measuring N2O fluxes from soils and from sewage treatment processes, and preliminary data indicate that urban N2O fluxes are higher than initially assumed by managers and regulatory agencies.

  18. Nitrous oxide emissions are enhanced in a warmer and wetter world.

    Science.gov (United States)

    Griffis, Timothy J; Chen, Zichong; Baker, John M; Wood, Jeffrey D; Millet, Dylan B; Lee, Xuhui; Venterea, Rodney T; Turner, Peter A

    2017-11-07

    Nitrous oxide (N2O) has a global warming potential that is 300 times that of carbon dioxide on a 100-y timescale, and is of major importance for stratospheric ozone depletion. The climate sensitivity of N2O emissions is poorly known, which makes it difficult to project how changing fertilizer use and climate will impact radiative forcing and the ozone layer. Analysis of 6 y of hourly N2O mixing ratios from a very tall tower within the US Corn Belt-one of the most intensive agricultural regions of the world-combined with inverse modeling, shows large interannual variability in N2O emissions (316 Gg N2O-N⋅y(-1) to 585 Gg N2O-N⋅y(-1)). This implies that the regional emission factor is highly sensitive to climate. In the warmest year and spring (2012) of the observational period, the emission factor was 7.5%, nearly double that of previous reports. Indirect emissions associated with runoff and leaching dominated the interannual variability of total emissions. Under current trends in climate and anthropogenic N use, we project a strong positive feedback to warmer and wetter conditions and unabated growth of regional N2O emissions that will exceed 600 Gg N2O-N⋅y(-1), on average, by 2050. This increasing emission trend in the US Corn Belt may represent a harbinger of intensifying N2O emissions from other agricultural regions. Such feedbacks will pose a major challenge to the Paris Agreement, which requires large N2O emission mitigation efforts to achieve its goals. Published under the PNAS license.

  19. Effects of dissolved oxygen and pH on nitrous oxide production rates in autotrophic partial nitrification granules.

    Science.gov (United States)

    Rathnayake, Rathnayake M L D; Oshiki, Mamoru; Ishii, Satoshi; Segawa, Takahiro; Satoh, Hisashi; Okabe, Satoshi

    2015-12-01

    The effects of dissolved oxygen (DO) and pH on nitrous oxide (N2O) production rates and pathways in autotrophic partial nitrification (PN) granules were investigated at the granular level. N2O was primarily produced by betaproteobacterial ammonia-oxidizing bacteria, mainly Nitrosomonas europaea, in the oxic surface layer (<200μm) of the autotrophic PN granules. N2O production increased with increasing bulk DO concentration owing to activation of the ammonia (i.e., hydroxylamine) oxidation in this layer. The highest N2O emissions were observed at pH 7.5, although the ammonia oxidation rate was unchanged between pH 6.5 and 8.5. Overall, the results of this study suggest that in situ analyses of PN granules are essential to gaining insight into N2O emission mechanisms in a granule. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Low nitrous oxide production through nitrifier-denitrification in intermittent-feed high-rate nitritation reactors

    DEFF Research Database (Denmark)

    Su, Qingxian; Ma, Chun; Domingo-Felez, Carlos

    2017-01-01

    Nitrous oxide (N2O) production from autotrophic nitrogen conversion processes, especially nitritation systems, can be significant, requires understanding and calls for mitigation. In this study, the rates and pathways of N2O production were quantified in two lab-scale sequencing batch reactors...... operated with intermittent feeding and demonstrating long-term and high-rate nitritation. The resulting reactor biomass was highly enriched in ammonia-oxidizing bacteria, and converted ∼93 ± 14% of the oxidized ammonium to nitrite. The low DO set-point combined with intermittent feeding was sufficient...... to maintain high nitritation efficiency and high nitritation rates at 20-26 °C over a period of ∼300 days. Even at the high nitritation efficiencies, net N2O production was low (∼2% of the oxidized ammonium). Net N2O production rates transiently increased with a rise in pH after each feeding, suggesting...

  1. Nitrous oxide emissions and dissolved oxygen profiling in a full-scale nitrifying activated sludge treatment plant.

    Science.gov (United States)

    Aboobakar, Amina; Cartmell, Elise; Stephenson, Tom; Jones, Mark; Vale, Peter; Dotro, Gabriela

    2013-02-01

    This paper reports findings from online, continuous monitoring of dissolved and gaseous nitrous oxide (N₂O), combined with dissolved oxygen (DO) and ammonia loading, in a full-scale nitrifying activated sludge plant. The study was conducted over eight weeks, at a 210,000 population equivalent sewage treatment works in the UK. Results showed diurnal variability in the gaseous and dissolved N₂O emissions, with hourly averages ranging from 0 to 0.00009 kgN₂O-N/h for dissolved and 0.00077-0.0027 kgN₂O-N/h for gaseous nitrous oxide emissions respectively, per ammonia loading, depending on the time of day. Similarly, the spatial variability was high, with the highest emissions recorded immediately after the anoxic zone and in the final pass of the aeration lane, where ammonia concentrations were typically below 0.5 mg/L. Emissions were shown to be negatively correlated to dissolved oxygen, which fluctuated between 0.5 and 2.5 mgO₂/L, at the control set point of 1.5 mgO₂/L. The resulting dynamic DO conditions are known to favour N₂O production, both by autotrophic and heterotrophic processes in mixed cultures. Average mass emissions from the lane were greater in the gaseous (0.036% of the influent total nitrogen) than in the dissolved (0.01% of the influent total nitrogen) phase, and followed the same diurnal and spatial patterns. Nitrous oxide emissions corresponded to over 34,000 carbon dioxide equivalents/year, adding 13% to the carbon footprint associated with the energy requirements of the monitored lane. A clearer understanding of emissions obtained from real-time data can help towards finding the right balance between improving operational efficiency and saving energy, without increasing N₂O emissions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Assessment of Nitrous Oxide Concentration in the Operating and Recovery Rooms of Babol University of Medical Sciences

    Directory of Open Access Journals (Sweden)

    Yusef Mortazavi

    2013-09-01

    Full Text Available Background & purpose: There are occupational hazards related to Nitrous Oxide (N2O in hospitals operating and recovery rooms. These hazards include the decrease of mental performance and audio-visual ability, and reduced fertility, spontaneous abortion and neurological, renal and liver diseases. In this survey, the concentration of Nitrous Oxide in indoor air of hospitals operating and recovery rooms in Babol University of medical sciences was determined. Materials & Methods: This descriptive study was performed in 23 operating rooms and 3 recovery rooms in 3 educational hospitals of Babol medical sciences university. The rooms with continuous usage of N2O with 2-3 lit/min of flow of general anesthesia were studied. For sampling and detecting N2O concentration as part per million (ppm, a portable IR spectrophotometer (3015 model of Bacharach Inc. was used. The sampling was performed in 5 different zones of the operating rooms and 1zone of recovery room in 3 different hours of work time (8:30-9AM, 10:30-11AM and 12:30-1:00PM. One-way ANOVA ,SPSS 18 was used to analyze data and comparing the means. Results: N2O concentration mean in 5 different zones of the operating rooms was 318± 22.6, 325.5± 24.1, 299± 21.8, and 301± 22, 314± 23.7 ppm and in recovery room, it was 51± 15 ppm. There was no significant difference between the means of N2O concentration in different zones of the operating rooms, but the means of N2O concentration in different zones of the operating rooms and recovery room were significant (p<0.05. Conclusion: Considering high average concentration of Nitrous Oxide in different operating and recovery rooms with maximum contamination levels of N2O, this situation subjects the health personnel to risk. Therefore, further research and applying protection utilities are recommended.

  3. Effects of contrasting catch crops on nitrogen availability and nitrous oxide emissions in an organic cropping system

    OpenAIRE

    Li, Xiaoxi; Petersen, Søren O.; Sørensen, Peter; Olesen, Jørgen E.

    2015-01-01

    Abstract Legume-based catch crops (LBCCs) may act as an important source of nitrogen (N) in organic crop rotations because of biological N fixation. However, the potential risk of high nitrous oxide (N2O) emissions needs to be taken into account when including LBCCs in crop rotations. Here, we report the results from a one-year field experiment, which investigated N availability and N2O emissions as affected by three LBCCs, i.e., red clover (CL), red clover–ryegrass mixture (GC) and winter ve...

  4. Coupling simultaneous dissolved nitrate measurements with quantum cascade laser based nitrous oxide flux and isotopocule analysis to investigate the biogeochemical processes occurring in a denitrifying bioreactor.

    Science.gov (United States)

    Williams, D. J.; Maxwell, B.; Deshmukh, P.; Chen, H.

    2016-12-01

    Denitrifying bioreactors are used to treat nitrogen enriched water from agricultural operations. These systems may also be an important source of nitrous oxide emissions, a potent greenhouse gas. Bioreactors also provide researchers with an opportunity to investigate the biogeochemical processes occurring in soils under controlled conditions. A pilot-scale bioreactor with woodchip media was injected with KNO3 at a constant flow rate through the system. The water-filled-pore-space (WFPS) was varied in separate experiments to create differing aerobic conditions. A quantum cascade laser spectroscopy system was used to determine the flux and isotopic signature of N2O emissions from woodchip bioreactor media over time. Simultaneous nitrate concentration measurements were made using an optical method at multiple points in the bioreactor. Isotopic site-preference (SP) characterization of N2O emissions was used to estimate production sources from soil nitrification and denitrification. A dynamic gas sampling method was used to measure N2O mixing ratios, which required ambient air to equalize chamber atmospheric pressure during sampling. Precise instrument calibration using gas samples of known isotopic abundances, provided by the Swiss Federal Labs (EMPA), together with a Keeling plot method to account for variations in isotopocule composition in ambient air, produced reliable SP estimates. Initial experiments during 100% WFPS show that SP and δ15Nbulk values were varied from -6‰ to 3‰ and -23‰ to -12‰, respectively. The trend of these values indicated that the N2O source was slightly changed from partial nitrification to denitrification during the measuring period of time. The peak rate of nitrous oxide production occurred 7 hours after peak nitrate removal. These results and others to be presented show the utility of coupling real-time dissolved and gas phase measurements for studying nitrogen cycling in soils.

  5. Nitrous oxide distribution and its origin in the central and eastern South Pacific Subtropical Gyre

    Directory of Open Access Journals (Sweden)

    J. Charpentier

    2007-09-01

    Full Text Available The mechanisms of microbial nitrous oxide (N2O production in the ocean have been the subject of many discussions in recent years. New isotopomeric tools can further refine our knowledge of N2O sources in natural environments. This study compares hydrographic, N2O concentration, and N2O isotopic and isotopomeric data from three stations along a coast-perpendicular transect in the South Pacific Ocean, extending from the center (Sts. GYR and EGY of the subtropical oligotrophic gyre (~26° S; 114° W to the upwelling zone (St. UPX off the central Chilean coast (~34° S. Although AOU/N2O and NO3 trends support the idea that most of the N2O (mainly from intermediate water (200–600 m comes from nitrification, N2O isotopomeric composition (intramolecular distribution of 15N isotopes expressed as SP (site preference of 15N shows low values (10 to 12permil that could be attributed to the production through of microbial nitrifier denitrification (reduction of nitrite to N2O mediated by ammonium oxidizers. The coincidence of this SP signal with high – stability layer, where sinking organic particles can accumulate, suggests that N2O could be produced by nitrifier denitrification inside particles. It is postulated that deceleration of particles in the pycnocline can modify the advection - diffusion balance inside particles, allowing the accumulation of nitrite and O2 depletion suitable for nitrifier denitrication. As lateral advection seems to be relatively insignificant in the gyre, in situ nitrifier denitrification could account for 40–50% of the N2O produced in this layer. In contrast, coastal upwelling system is characterized by O2 deficient condition and some N deficit in a eutrophic system. Here, N2O accumulates up to 480% saturation, and isotopic and

  6. Drought effect on methane, nitrous oxide and carbon dioxide dynamics along boreal forest-mire ecotone

    Science.gov (United States)

    Ťupek, Boris; Minkkinen, Kari; Vesala, Timo; Kolari, Pasi; Starr, Mike; Alm, Jukka; Pumpanen, Jukka; Berninger, Frank; Laine, Jukka; Nikinmaa, Eero

    2013-04-01

    The effect of drought on CH4, N2O and CO2 dynamics of boreal forest and mires has been seldom observed in a continuum between xeric and wet habitats. Such a continuum includes a transitional zone between forests and mires which is frequently exposed to large soil moisture differences, but generally overlooked due to a relatively narrow extent. Although, it's known that CH4, N2O and CO2 dynamics are sensitive to soil moisture. We evaluated spatiotemporal effects of drought on CH4, N2O and CO2 dynamics in continuum of nine distinct forest/mire types. Soils changed from well-drained podzols to poorly-drained histosols and ground water raised downslope from the depth of 10 m in upland forests to 0.1 m in mires. Meteorological conditions, forest floor respiration, methane, and nitrous oxide flux data were collected during growing season of exceptionally wet (2004), intermediate (2005), and exceptionally dry (2006) year. The CH4, N2O and CO2 fluxes were studied by chamber methods. The seasonal median forest floor CH4, N2O, and CO2 dark fluxes between forest/mire types and between rainy, intermediate, and dry years varied from -0.07 to 1.68 mgCH4 m2 h-1, from 1.5 to 24.65 μgN2O m2 h-1, and from 0.26 to 0.76 gCO2 m2 h-1. The CH4 oxidation in upland forest and transitional types was similar between wet and dry years, though the CH4 production of mires was reduced in dry year. Probably due to low nitrification potential, larger soil water differences between years 2005 and 2006 did not seem to trigger corresponding changes in small N2O fluxes. The forest floor dark CO2 efflux during drought was in comparison to wetter periods significantly reduced in upland forest and transitional types, but stayed similar or even increased in mires. In the carbon rich soil of forest/mire transitions mainly soil CO2 efflux were sensitive to short term fluctuations between water level drawdown and water saturation, whereas CH4 and N2O fluxes changed minimally.

  7. Nitrous Oxide (N2O Emissions by Termites: Does the Feeding Guild Matter?

    Directory of Open Access Journals (Sweden)

    Alain Brauman

    Full Text Available In the tropics, termites are major players in the mineralization of organic matter leading to the production of greenhouse gases including nitrous oxide (N2O. Termites have a wide trophic diversity and their N-metabolism depends on the feeding guild. This study assessed the extent to which N2O emission levels were determined by termite feeding guild and tested the hypothesis that termite species feeding on a diet rich in N emit higher levels of N2O than those feeding on a diet low in N. An in-vitro incubation approach was used to determine the levels of N2O production in 14 termite species belonging to different feeding guilds, collected from a wide range of biomes. Fungus-growing and soil-feeding termites emit N2O. The N2O production levels varied considerably, ranging from 13.14 to 117.62 ng N2O-N d(-1 (g dry wt.(-1 for soil-feeding species, with Cubitermes spp. having the highest production levels, and from 39.61 to 65.61 ng N2O-N d(-1 (g dry wt.(-1 for fungus-growing species. Wood-feeding termites were net N2O consumers rather than N2O producers with a consumption ranging from 16.09 to 45.22 ng N2O-N d(-1 (g dry wt.(-1. Incubating live termites together with their mound increased the levels of N2O production by between 6 and 13 fold for soil-feeders, with the highest increase in Capritermes capricornis, and between 14 and 34 fold for fungus-growers, with the highest increase in Macrotermes muelleri. Ammonia-oxidizing (amoA-AOB and amoA-AOA and denitrifying (nirK, nirS, nosZ gene markers were detected in the guts of all termite species studied. No correlation was found between the abundance of these marker genes and the levels of N2O production from different feeding guilds. Overall, these results support the hypothesis that N2O production rates were higher in termites feeding on substrates with higher N content, such as soil and fungi, compared to those feeding on N-poor wood.

  8. Nitrous Oxide (N2O) Emissions by Termites: Does the Feeding Guild Matter?

    Science.gov (United States)

    Brauman, Alain; Majeed, Muhammad Zeeshan; Buatois, Bruno; Robert, Alain; Pablo, Anne-Laure; Miambi, Edouard

    2015-01-01

    In the tropics, termites are major players in the mineralization of organic matter leading to the production of greenhouse gases including nitrous oxide (N2O). Termites have a wide trophic diversity and their N-metabolism depends on the feeding guild. This study assessed the extent to which N2O emission levels were determined by termite feeding guild and tested the hypothesis that termite species feeding on a diet rich in N emit higher levels of N2O than those feeding on a diet low in N. An in-vitro incubation approach was used to determine the levels of N2O production in 14 termite species belonging to different feeding guilds, collected from a wide range of biomes. Fungus-growing and soil-feeding termites emit N2O. The N2O production levels varied considerably, ranging from 13.14 to 117.62 ng N2O-N d(-1) (g dry wt.)(-1) for soil-feeding species, with Cubitermes spp. having the highest production levels, and from 39.61 to 65.61 ng N2O-N d(-1) (g dry wt.)(-1) for fungus-growing species. Wood-feeding termites were net N2O consumers rather than N2O producers with a consumption ranging from 16.09 to 45.22 ng N2O-N d(-1) (g dry wt.)(-1). Incubating live termites together with their mound increased the levels of N2O production by between 6 and 13 fold for soil-feeders, with the highest increase in Capritermes capricornis, and between 14 and 34 fold for fungus-growers, with the highest increase in Macrotermes muelleri. Ammonia-oxidizing (amoA-AOB and amoA-AOA) and denitrifying (nirK, nirS, nosZ) gene markers were detected in the guts of all termite species studied. No correlation was found between the abundance of these marker genes and the levels of N2O production from different feeding guilds. Overall, these results support the hypothesis that N2O production rates were higher in termites feeding on substrates with higher N content, such as soil and fungi, compared to those feeding on N-poor wood.

  9. Mechanisms of inorganic nitrous oxide production in soils during nitrification and their dependence on soil properties

    Science.gov (United States)

    Heil, Jannis; Liu, Shurong; Vereecken, Harry; Brüggemann, Nicolas

    2014-05-01

    Nitrous oxide (N2O) is an important anthropogenic greenhouse gas and today's single most ozone depleting substance. Soils have been identified as the major source of N2O. Microbial nitrification and denitrification are considered the major N2O emission sources. However, N2O production in soils, especially during nitrification, is far from being completely understood. Several abiotic reactions involving the nitrification intermediate hydroxylamine (NH2OH) have been identified leading to N2O emissions, but are being neglected in most current studies. However, it is known that NH2OH can be oxidized by several soil constituents to form N2O. For better mitigation strategies it is mandatory to understand the underlying processes of N2O production during nitrification and their controlling factors. We studied N2O emissions from different soils in laboratory incubation experiments. Soils covered a wide range of land use types from arable to grassland and forest. Soil incubations were conducted with and without the addition of NH2OH at conditions favorable for nitrification with non-sterile as well as with sterile samples. N2O and, additionally, CO2 evolution were analyzed using gas chromatography. To get insight into the dynamics of N2O formation, N2O production from NH2OH was quantified online using quantum cascade laser absorption spectroscopy. Furthermore, isotope ratio mass spectrometry was used to analyze the isotopic signature of the produced N2O (i.e. δ15N, δ18O, and 15N site preference). We observed large differences in N2O emissions between different soils upon the addition of NH2OH. While a forest soil sample with pH caused by NH2OH addition. Although it was shown in the past that NH2OH can react with Fe(III) to form N2O, we could not find any correlation between Fe concentration in soils and N2O emission rates. Our results suggest a coupled biotic-abiotic production of N2O during nitrification. We hypothesize that N2O production is the result of a leakage of

  10. The response of methane and nitrous oxide fluxes to forest change in Europe

    Science.gov (United States)

    Gundersen, P.; Christiansen, J. R.; Alberti, G.; Brüggemann, N.; Castaldi, S.; Gasche, R.; Kitzler, B.; Klemedtsson, L.; Lobo-do-Vale, R.; Moldan, F.; Rütting, T.; Schleppi, P.; Weslien, P.; Zechmeister-Boltenstern, S.

    2012-10-01

    Forests in Europe are changing due to interactions between climate change, nitrogen (N) deposition and new forest management practices. The concurrent impact on the forest greenhouse gas (GHG) balance is at present difficult to predict due to a lack of knowledge on controlling factors of GHG fluxes and response to changes in these factors. To improve the mechanistic understanding of the ongoing changes, we studied the response of soil-atmosphere exchange of nitrous oxide (N2O) and methane (CH4) at twelve experimental or natural gradient forest sites, representing anticipated future forest change. The experimental manipulations, one or more per site, included N addition (4 sites), changes of climate (temperature, 1 site; precipitation, 2 sites), soil hydrology (3 sites), harvest intensity (1 site), wood ash fertilisation (1 site), pH gradient in organic soil (1 site) and afforestation of cropland (1 site). On average, N2O emissions increased by 0.06 ± 0.03 (range 0-0.3) g N2O-N m-2 yr-1 across all treatments on mineral soils, but the increase was up to 10 times higher in an acidic organic soil. Soil moisture together with mineral soil C / N ratio and pH were found to significantly influence N2O emissions across all treatments. Emissions were increased by elevated N deposition, especially in interaction with increased soil moisture. High pH reduced the formation of N2O, even under otherwise favourable soil conditions. Oxidation (uptake) of CH4 was on average reduced from 0.16 ± 0.02 to 0.04 ± 0.05 g CH4-C m-2 yr-1 by the investigated treatments. The CH4 exchange was significantly influenced by soil moisture and soil C / N ratio across all treatments, and CH4 emissions occurred only in wet or water-saturated conditions. For most of the investigated forest manipulations or natural gradients, the response of both N2O and CH4 fluxes was towards reducing the overall GHG forest sink. The most resilient forests were dry Mediterranean forests, as well as forests with high

  11. Nitric oxides and nitrous oxide fluxes from typical vegetables cropland in China: Effects of canopy, soil properties and field management

    Science.gov (United States)

    Pang, Xiaobing; Mu, Yujing; Lee, Xinqing; Fang, Shuangxi; Yuan, Juan; Huang, Daikuan

    In China, vegetable croplands are characterized by intensive fertilization and cultivation, which produce significant nitrogenous gases to the atmosphere. In this study, nitric oxides (NO X) and nitrous oxide (N 2O) emissions from the croplands cultivated with three typical vegetables had been measured in Yangtze River Delta of China from September 2 to December 16, 2006. The NO fluxes varied in the ranges of 1.6-182.4, 1.4-2901 and 0.5-487 ng Nm -2 s -1 with averages of 33.8 ± 44.2, 360 ± 590 and 76 ± 112 (mean ± SD) ngNm -2 s -1 for cabbage, garlic, and radish fields ( n = 88), respectively. N 2O fluxes from the three vegetable fields were found to occur in pulses and significantly promoted by tillage with average values of 5.8, 8.8, and 4.3 ng Nm -2 h -1 for cabbage, garlic, and radish crops, respectively. Influence of vegetables canopy on the NO emission was investigated and quantified. It was found that on cloudy days the canopy can only shield NO emission from croplands soil while on sunny days it cannot only prevent NO emission but also assimilate NO through the open leaves stomas. Multiple linear regression analysis indicated that soil temperature was the most important factor in controlling NO emission, followed by fertilizer amount and gravimetric soil water content. About 1.2%, 11.56% and 2.56% of applied fertilizers N were emitted as NO-N and N 2O-N from the cabbage, garlic and radish plots, respectively.

  12. Nitric Oxide and Nitrous Oxide Production by Soybean and Winged Bean during the in Vivo Nitrate Reductase Assay.

    Science.gov (United States)

    Dean, J V; Harper, J E

    1986-11-01

    This study was conducted to determine by gas chromatography (GC) and mass spectrometry (MS) the identity and the quantity of volatile N products produced during the helium-purged in vivo NR assay of soybean (Glycine max [L.] Merr. cv Williams) and winged bean (Psophocarpus tetragonolobus [L.] DC. cv Lunita) leaflets. Gaseous material for identification and quantitation was collected by cryogenic trapping of volatile compounds carried in the He-purge gas stream. As opposed to an earlier report, acetaldehyde oxime production was not detected by our GC method, and acetaldehyde oxime was shown to be much more soluble in water than the compound(s) evolved from soybean leaflets. Nitric oxide (NO) and nitrous oxide (N(2)O) were identified by GC and GC/MS as the main N products formed. NO and N(2)O produced from soybean leaflets were both labeled with (15)N when (15)N-nitrate was used in the assay medium, demonstrating that both were produced from nitrate during nitrate reduction. Other compounds co-trapped with NO and N(2)O were identified as air (N(2), O(2)), CO(2), methanol, acetaldehyde, and ethanol. Leaves of winged bean, subjected to the purged in vivo NR assay, evolved greater quantities of NO and N(2)O (13.9 and 0.37 micromole per gram fresh weight per 30 minutes, respectively) than did the soybean cv Williams (1.67 and 0.09 micromole per gram fresh weight per 30 minutes, respectively). In both species NO production was dominant. In contrast, with similar assays, NO and N(2)O were not evolved from leaves of the nr(1) soybean mutant which lacks the constitutive NR enzymes. In addition to soybean cv Williams, six other Glycine sp. examined evolved significant quantities of NO((x)) (NO and NO(2)). Other species including Neonotonia wightii (Arn.) Lackey comb. nov., Pueraria montana (Lour.) Merr., and Pueraria thunbergiana Benth. evolved lower levels of NO((x)).

  13. Nitrous-acid-mediated synthesis of iron-nitrosyl-porphyrin: pH-dependent release of nitric oxide.

    Science.gov (United States)

    Bhuyan, Jagannath; Sarkar, Sabyasachi

    2012-11-01

    Two iron-nitrosyl-porphyrins, nitrosyl[meso-tetrakis(3,4,5-trimethoxyphenylporphyrin]iron(II) acetic acid solvate (3) and nitrosyl[meso-tetrakis(4-methoxyphenylporphyrin]iron(II) CH(2)Cl(2) solvate (4), were synthesized in quantitative yield by using a modified procedure with nitrous acid, followed by oxygen-atom abstraction by triphenylphosphine under an argon atmosphere. These nitrosyl porphyrins are in the {FeNO}(7) class. Under an argon atmosphere, these compounds are relatively stable over a broad range of pH values (4-8) but, under aerobic conditions, they release nitric oxide faster at high pH values than that at low pH values. The generated nitric-oxide-free iron(III)-porphyrin can be re-nitrosylated by using nitrous acid and triphenylphosphine. The rapid release of NO from these Fe(II) complexes at high pH values seems to be similar to that in nitrophorin, a nitric-oxide-transport protein, which formally possesses Fe(III). However, because the release of NO occurs from ferrous-nitrosyl-porphyrin under aerobic conditions, these compounds are more closely related to nitrobindin, a recently discovered heme protein. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Effects of nitrous oxide on the production of cytokines and chemokines by the airway epithelium during anesthesia with sevoflurane and propofol.

    Science.gov (United States)

    Kumakura, Seiichiro; Yamaguchi, Keisuke; Sugasawa, Yusuke; Murakami, Taisuke; Kikuchi, Toshihiro; Inada, Eiichi; Nagaoka, Isao

    2013-12-01

    The aim of this study was to evaluate the effects of nitrous oxide (a gaseous anesthetic) on the in vivo production of inflammatory cytokines and chemokines by the airway epithelium, when combined with sevoflurane or propofol. Subjects undergoing simple or segmental mastectomy were randomly assigned to the sevoflurane and nitrous oxide, sevoflurane and air, propofol and nitrous oxide, or propofol and air group (all n=13). Epithelial lining fluid (ELF) was obtained using the bronchoscopic microsampling method prior to and following the mastectomy to enable measurement of the pre- and post-operative levels of certain inflammatory cytokines and chemokines using a cytometric bead array system. Notably, the levels of interleukin (IL)-1β, IL-8 and monocyte chemotactic protein-1 (MCP-1) in the ELF were significantly increased following the operations which involved the inhalation of sevoflurane and nitrous oxide, although the levels of these molecules were not significantly changed by the inhalation of sevoflurane and air. Furthermore, the IL-12p70 levels were significantly reduced in the ELF following the operations that involved the inhalation of sevoflurane and air, although the IL-12p70 levels were not significantly changed by the inhalation of nitrous oxide and sevoflurane. These observations suggest that the combination of sevoflurane and nitrous oxide induces an inflammatory response (increased production of IL-1β, IL-8 and MCP-1) and suppresses the anti-inflammatory response (reduced production of IL-12p70) in the local milieu of the airway. Thus, the combination of these compounds should be carefully administered for anesthesia.

  15. Nitrous oxide/oxygen mixture for analgesia in adult cancer patients with breakthrough pain: A randomized, double-blind controlled trial.

    Science.gov (United States)

    Liu, Q; Gao, L-L; Dai, Y-L; Li, Y-X; Wang, Y; Bai, C-F; Mu, G-X; Chai, X-M; Han, W-J; Zhou, L-J; Zhang, Y-J; Tang, L; Liu, J; Yu, J-Q

    2017-12-11

    The aim of this study was to assess the efficacy of a fixed nitrous oxide/oxygen mixture for the management of breakthrough cancer pain. A double-blind, placebo-controlled, randomized clinical trial was undertaken in the Medical ward of Tumor Hospital of General Hospital of Ningxia Medical University. 240 cancer patients with breakthrough pain were recruited and randomly received a standard pain treatment (morphine sulphate immediate release) plus a pre-prepared nitrous oxide/oxygen mixture, or the standard pain treatment plus oxygen. The primary endpoint measure was the numerical rating scale (NRS) score measured at baseline, 5 and 15 min after the beginning of treatment, and at 5 min post treatment. In all, analysis of pain score (NRS) at 5 min after the beginning of treatment shown a significant decrease in nitrous oxide/oxygen mixture treated patients with 2.8 ± 1.3 versus 5.5 ± 1.2 in controls (p nitrous oxide/oxygen was 2.0 ± 1.1 compared with 5.6 ± 1.3 for oxygen (p nitrous oxide/oxygen mixture was effective in reducing moderate to severe breakthrough pain among patients with cancer. The management of breakthrough cancer pain is always a challenge due to its temporal characteristics of rapid onset, moderate to severe in intensity, short duration (median 30-60 min). Our study find that self-administered nitrous oxide/oxygen mixture was effective in reducing moderate to severe breakthrough cancer pain. © 2017 European Pain Federation - EFIC®.

  16. Nitric oxide and nitrous oxide turnover in natural and engineered microbial communities: biological pathways, chemical reactions, and novel technologies

    Science.gov (United States)

    Schreiber, Frank; Wunderlin, Pascal; Udert, Kai M.; Wells, George F.

    2012-01-01

    Nitrous oxide (N2O) is an environmentally important atmospheric trace gas because it is an effective greenhouse gas and it leads to ozone depletion through photo-chemical nitric oxide (NO) production in the stratosphere. Mitigating its steady increase in atmospheric concentration requires an understanding of the mechanisms that lead to its formation in natural and engineered microbial communities. N2O is formed biologically from the oxidation of hydroxylamine (NH2OH) or the reduction of nitrite (NO−2) to NO and further to N2O. Our review of the biological pathways for N2O production shows that apparently all organisms and pathways known to be involved in the catabolic branch of microbial N-cycle have the potential to catalyze the reduction of NO−2 to NO and the further reduction of NO to N2O, while N2O formation from NH2OH is only performed by ammonia oxidizing bacteria (AOB). In addition to biological pathways, we review important chemical reactions that can lead to NO and N2O formation due to the reactivity of NO−2, NH2OH, and nitroxyl (HNO). Moreover, biological N2O formation is highly dynamic in response to N-imbalance imposed on a system. Thus, understanding NO formation and capturing the dynamics of NO and N2O build-up are key to understand mechanisms of N2O release. Here, we discuss novel technologies that allow experiments on NO and N2O formation at high temporal resolution, namely NO and N2O microelectrodes and the dynamic analysis of the isotopic signature of N2O with quantum cascade laser absorption spectroscopy (QCLAS). In addition, we introduce other techniques that use the isotopic composition of N2O to distinguish production pathways and findings that were made with emerging molecular techniques in complex environments. Finally, we discuss how a combination of the presented tools might help to address important open questions on pathways and controls of nitrogen flow through complex microbial communities that eventually lead to N2O build

  17. Nitric oxide and nitrous oxide turnover in natural and engineered microbial communities: biological pathways, chemical reactions and novel technologies

    Directory of Open Access Journals (Sweden)

    Frank eSchreiber

    2012-10-01

    Full Text Available Nitrous oxide (N2O is an environmentally important atmospheric trace gas because it is an effective greenhouse gas and it leads to ozone depletion through photo-chemical nitric oxide (NO production in the stratosphere. Mitigating its steady increase in atmospheric concentration requires an understanding of the mechanisms that lead to its formation in natural and engineered microbial communities. N2O is formed biologically from the oxidation of hydroxylamine (NH2OH or the reduction of nitrite (NO2- to NO and further to N2O. Our review of the biological pathways for N2O production shows that apparently all organisms and pathways known to be involved in the catabolic branch of microbial N-cycle have the potential to catalyze the reduction of NO2- to NO and the further reduction of NO to N2O, while N2O formation from NH2OH is only performed by ammonia oxidizing bacteria. In addition to biological pathways, we review important chemical reactions that can lead to NO and N2O formation due to the reactivity of NO2-, NH2OH and nitroxyl (HNO. Moreover, biological N2O formation is highly dynamic in response to N-imbalance imposed on a system. Thus, understanding NO formation and capturing the dynamics of NO and N2O build-up are key to understand mechanisms of N2O release. Here, we discuss novel technologies that allow experiments on NO and N2O formation at high temporal resolution, namely NO and N2O microelectrodes and the dynamic analysis of the isotopic signature of N2O with quantum cascade laser based absorption spectroscopy. In addition, we introduce other techniques that use the isotopic composition of N2O to distinguish production pathways and findings that were made with emerging molecular techniques in complex environments. Finally, we discuss how a combination of the presented tools might help to address important open questions on pathways and controls of nitrogen flow through complex microbial communities that eventually lead to N2O build-up.

  18. Quantification and modeling of nitrate consumption, and nitrous oxide and nitrite production during push-pull tracer tests

    Science.gov (United States)

    Boisson, A.; De Anna, P.; Bour, O.; Le Borgne, T.; Aquilina, L.

    2011-12-01

    Field quantitative estimation of reaction kinetics is required to enhance our understanding of biogeochemical reactions in aquifers and to model the different element production/consumption. In this study, we quantify kinetics of nitrate consumption and by-products formation (nitrites and nitrous oxide) during autotrophic denitrification using push-pull tracer tests in a fractured crystalline aquifer (Ploemeur, French Brittany). Previous studies (Tarits et al., 2006) have shown that this very heterogeneous aquifer was characterized by the occurrence of an autotrophic denitrification reaction related to pyrite bearing fractures. Reactivity assessment by push-pull tests consists in injecting a well known solution composed of a reactive (NO3-) and a non reactive tracer (Br-) in a borehole (push phase). After a time lag the solution is pumped (pull phase) from the same borehole to obtain breakthrough curves. Comparison of the breakthrough curves of both tracers provides the consumed mass. Comparison of Br- and NO3- breakthrough curves shows that 10 % of the injected nitrate molar mass was transformed during the 12 hours experiment (2% in NO2-, 1% in N2O and the rest in N2 and NO). This experiment shows that push pull tests are reliable to assess autotrophic denitrification reaction by providing an in situ quantification of nitrate reduction and by-products formation. Similar results with comparable kinetics are obtained from laboratory experiments in reactors. To model the whole denitrification reaction, we extend the simplified analytical solution developed by Haggerty et al. (1998) through a first order reaction chain for push pull experiments analysis allowing the estimation of kinetic parameters for each reaction step. Then we assess the ability of this reaction chain to model biogeochemical reactions by comparing it to our experimental results. Good fit between model and experimental results indicate the possibility to consider the complete denitrification process

  19. Effects of irrigation on nitrous oxide, methane and carbon dioxide fluxes in an Inner Mongolian steppe

    Science.gov (United States)

    Liu, Chunyan; Holst, Jirko; Brüggemann, Nicolas; Butterbach-Bahl, Klaus; Yao, Zhisheng; Han, Shenghui; Han, Xingguo; Zheng, Xunhua

    2008-09-01

    Increased precipitation during the vegetation periods was observed in and further predicted for Inner Mongolia. The changes in the associated soil moisture may affect the biosphere-atmosphere exchange of greenhouse gases. Therefore, we set up an irrigation experiment with one watered (W) and one unwatered plot (UW) at a winter-grazed Leymus chinensis-steppe site in the Xilin River catchment, Inner Mongolia. UW only received the natural precipitation of 2005 (129 mm), whereas W was additionally watered after the precipitation data of 1998 (in total 427 mm). In the 3-hour resolution, we determined nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) fluxes at both plots between May and September 2005, using a fully automated, chamber-based measuring system. N2O fluxes in the steppe were very low, with mean emissions (±s.e.) of 0.9±0.5 and 0.7±0.5 µg N m-2 h-1 at W and UW, respectively. The steppe soil always served as a CH4 sink, with mean fluxes of -24.1±3.9 and -31.1±5.3 µg C m-2 h-1 at W and UW. Nighttime mean CO2 emissions were 82.6±8.7 and 26.3±1.7 mg C m-2 h-1 at W and UW, respectively, coinciding with an almost doubled aboveground plant biomass at W. Our results indicate that the ecosystem CO2 respiration responded sensitively to increased water input during the vegetation period, whereas the effects on CH4 and N2O fluxes were weak, most likely due to the high evapotranspiration and the lack of substrate for N2O producing processes. Based on our results, we hypothesize that with the gradual increase of summertime precipitation in Inner Mongolia, ecosystem CO2 respiration will be enhanced and CH4 uptake by the steppe soils will be lightly inhibited.

  20. Nitrous oxide production and consumption by denitrification in a grassland: Effects of grazing and hydrology.

    Science.gov (United States)

    Hu, Jing; Inglett, Kanika S; Clark, Mark W; Inglett, Patrick W; Ramesh Reddy, K

    2015-11-01

    Denitrification is generally recognized as a major mechanism contributing to nitrous oxide (N2O) production, and is the only known biological process for N2O consumption. Understanding factors controlling N2O production and consumption during denitrification will provide insights into N2O emission variability, and potentially predict capacity of soils to serve as sinks or sources of N2O. This study investigated the effects of hydrology and grazing on N2O production and consumption in a grassland based agricultural watershed. A batch incubation study was conducted on soils (0-10 cm) collected along a hydrological gradient representing isolated wetland (Center), transient zone (Edge) and pasture upland (Upland), from both grazed and ungrazed areas. Production and consumption potentials of N2O were quantified on soils under four treatments, including (i) ambient condition, and amended with (ii) NO3(-), (iii) glucose-C, and (iv) NO3(-) +glucose-C. The impacts of grazing on N2O production and consumption were not observed. Soils in hydrologically distinct zones responded differently to N2O production and consumption. Under ambient conditions, both production and consumption rates of Edge soils were higher than those observed for Center and Upland soils. Results of amended incubations suggested NO3(-) was a key factor limiting N2O production and consumption rates in all hydrological zones. Over 5-d incubation with NO3(-) amendment, cumulative production and consumption of N2O for Center soils were 1.6 and 3.3 times higher than Edge soils, and 3.6 and 7.6 times higher than Upland soils, respectively. However, cumulative N2O net production for Edge soils was the highest, with 2 to 3 times higher than Upland and Center soils. Our results suggest that the transient areas between wetland and upland are likely to be "hot spots" of N2O emissions in this ecosystem. Wetlands within agricultural landscapes can potentially function to reduce both NO3(-) leaching and N2O emissions