Nitric Oxide SynthaseNitrogen FixationNitrogen OxidesNitrogen CompoundsNitrogen IsotopesNitrogen CycleNitric Oxide Synthase Type IINitrogen DioxideBlood Urea NitrogenPositron-Emission TomographyOxidesOtoacoustic Emissions, SpontaneousReactive Nitrogen SpeciesTomography, Emission-ComputedNitric Oxide Synthase Type IIINitratesVehicle EmissionsNitric Oxide Synthase Type IFluorodeoxyglucose F18RadiopharmaceuticalsCarbonAmmoniaNitritesFertilizersPII Nitrogen Regulatory ProteinsZinc OxideTomography, Emission-Computed, Single-PhotonArginineAir PollutantsGreenhouse EffectSoilNG-Nitroarginine Methyl EsterDenitrificationQuaternary Ammonium CompoundsFluorine RadioisotopesSpectrometry, FluorescenceAtmosphereMethaneomega-N-MethylarginineEnvironmental MonitoringEnzyme InhibitorsGlutamate-Ammonia LigaseUreaTime FactorsCarbon DioxideCarbon FootprintGasesAmino Acid OxidoreductasesBiomassOxidation-ReductionManureAir PollutionNitrogen Mustard CompoundsAmino AcidsNitrous OxideBrainVolatilizationOxygenFossil FuelsNitrogenaseNitroso CompoundsSymbiosisPlant LeavesCarbon RadioisotopesS-Nitroso-N-AcetylpenicillaminePentanesMultimodal ImagingKineticsMolecular Sequence DataCyclic GMPPlant RootsTomography, X-Ray ComputedNitroprussideRats, Sprague-DawleyFluorescent DyesPenicillamineAgricultureDose-Response Relationship, DrugLuminescenceEcosystemEndothelium, VascularBacterial ProteinsGasolineGlutamineDigestionFluorescenceFerrosoferric OxideHydrogen-Ion ConcentrationCerebrovascular CirculationSpectrometry, X-Ray EmissionMolsidomineNitrificationFerric CompoundsModels, BiologicalVasodilationAnimal FeedPeroxynitrous AcidTemperatureVolatile Organic CompoundsParticulate Matter