Low Levels Of NO Research Articles

Evaluation of Real-World Gaseous Emissions Performance of Selective Catalytic Reduction and Diesel Particulate Filter Bus Retrofits.

This study reports on the results of gaseous pollutants emission measurements of double-decker buses in an urban road network, using portable emission measurement systems (PEMS). Measured vehicles were tested by following in-service buses on regular routes. Six Euro II and Euro III buses were retrofitted with diesel particulate filters (DPF) and selective catalytic reduction (SCR) or a combined SCR+DPF (SCRT) device. Substantial and statistically significant technology impacts were observed for several pollutants. Optimized SCR and SCRT retrofit technology reduced real-world NO x emissions by approximately 70%, on average. Retrofit DPF slightly reduced NO x emissions but increased direct NO2 emissions by more than a factor of 8, on average. SCRT led to about 70% lower NO2 levels than DPF alone, but for some vehicles higher NO2 levels were observed as compared with the "no retrofit" situation, warranting further investigation. None of the SCR systems were found to lead to a substantial increase in NH3 emissions after operation optimization. High NH3 and N2O emissions were occasionally observed while experience with the system calibration was being accumulated. Observed average N2O emission levels for "DPF+SCR" technology were relatively high at 182 mg/kg fuel, corresponding to 1.5% of total greenhouse gas emissions. The study shows that SCR retrofit programs can be effective for NO x reduction of transit buses but that proper calibration and regular emission monitoring are required.

MONITORING OF CHRONIC SINUSITIS USING NASAL NITRIC OXIDE AS A MARKER OF SINUS HEALTH: A SYSTEMATIC REVIEW

It was reported that, nasal nitric oxide (nNO) is continuously released in the paranasal sinuses which acts as antibacterial and antiviral agent and improves mucociliary clearance in sinuses environment. The levels of nasal nitric oxide (nNO) are significantly changed with inflammatory stimuli as well as with medical or surgical treatment for chronic sinusitis. The present systematic review is aimed at evaluating the role of nNO as biomarker for monitoring chronic sinusitis. A web-based search was conducted in MEDLINE with inclusion criteria of human studies in English language that aimed to evaluate the role of nNO as in monitoring chronic sinusitis. Study designs adoptedwereobservational studies or clinical trials with comparisons between patient with chronic sinusitis in study group and control group of patients with flu or healthy population. The outcome assessed was the level of nNO in both groups. Data were collected for characteristics of included study such as study design, sample size, mean age, type and location of sinusitis, and technique and procedures used to monitor nitric oxide. The search on the monitoring of chronic sinusitis using nasal Nitric oxide (nNO) as marker of sinus health resulted in 97 articles, of them 81 articles were irrelevant and six articles were reviews. The included studies in this review were 10 studies. Overall findings showed that significantly lower levels of Nasal NO were reported in the patients with chronic rhinosinusitis (CRS) (irrespective of nasal polyps or allergic rhinitis concomitance) compared to healthy volunteers. The lower levels of Nasal NO in chronic rhinosinusitis are related to the decreasing of NO metabolites. The nasal nitric oxide could be employed as a good biomarker for monitoring the sinus health. The lower levels of nasal NO are indicators to the incidence ofchronic sinus inflammation in patients with chronic rhinosinusitis (CRS) These lower levels of nasal nitric oxide increase significantly after sinus therapy or surgical treatment.

Potential benefits and toxicity of nanoselenium and nitric oxide in peppermint

Taking account of nano-compounds and biofortification, this research was conducted to evaluate peppermint (Mentha x piperita L.) responses to nano-selenium (nSe; 0, 2, and 20 mg l-1) and/or nitric oxide (NO; 0 and 8 mg l-1). Significant increases in leaf length, and area, and shoot fresh mass were enhanced by the low level of nSe and/or NO, contrasted with the high dose. The inhibitory effects of the high dose of nSe on the growth-related characteristics were significantly mitigated by NO. The adverse impact of nSe20 on chlorophyll concentration was alleviated by NO. The individual and combined treatments of nSe2 led to the significant inductions in the activities of nitrate reductase and peroxidase, whereas nSe20 inhibited. The proline contents in the nSe and/or NO-treated plants were higher than in the control. The nSe and/or NO provoked stimulation in activities of phenylalanine ammonia lyase enzyme. The foliar applications of nSe and/or NO triggered the accumulations of soluble phenols. Interestingly, the toxicity of nSe at the high dose led to the severe cell destruction in the cortex layer of the basal stem, which was partially alleviated by NO. The simultaneous applications of these supplements may consider as an alternative strategy for fortifying and improving plant protection, regarding sustainable agriculture.

Reduced nasal nitric oxide levels in patients with eosinophilic chronic rhinosinusitis

BackgroundIn Eosinophilic chronic rhinosinusitis (ECRS), it is difficult to estimate the refractoriness and recurrence risk for each patient. Fraction of exhaled nitric oxide (FeNO) is known as a biomarker of eosinophilic inflammation in lower airway. It has been reported that nasal NO has some crucial functions in the upper and lower airways. However, in upper airway, paranasal sinuses, the usefulness of NO measurement remains controversial. The purpose of this study is to identify the usefulness of nasal NO measurement in ECRS and the involvement of nasal NO in the pathogenesis of ECRS. MethodsWe compared the nasal NO levels of ECRS, non-ECRS, and normal control groups. Correlation between nasal NO levels and clinical findings were observed. Then, we compared nasal NO levels before and after endoscopic sinus surgery (ESS). We also examine whether nasal NO levels might discriminate ECRS by the receiver operating characteristic (ROC) curve analysis. ResultsNasal NO levels were significantly decreased in ECRS compared to the other two groups. Moreover, nasal NO levels in ECRS significantly and negatively correlated with eosinophil levels and CT score. However, they did not correlate with the nasal polyp score. Nasal NO levels were not upregulated soon after opening the sinus ostium by ESS. The ROC curves for nasal NO levels were used to discriminate all CRS patients and ECRS patients from normal controls. ConclusionsNasal NO may be useful as a marker of ECRS severity and low nasal NO levels in ECRS may contribute to its pathogenesis.

Exposure to Metal Fume Particulate Matter and NO in Exhaled Breath in Shipyard Welders

Exposure to metal fume particulate matter has been linked to numerous adverse health endpoints. Clinical researches have been clarifying the relation of Fractional nitric oxide (FeNO) with airway inflammation in asthma. Despite this, limited data examining the relation of metal fume particulate matter exposure and NO in exhaled breath in welders.We conducted a cross-sectional study. Study participants consisted of 52 welders and 29 office workers. Exposure assessment was based on eight-hour measurement with a personal PM2.5 sampler of exposure to metal fume fine particle matter on Monday. On Tuesday morning, participants were instructed to fast for at least 10 hours prior to urine sampling. The concentration of NO in exhaled breath, an indicator of acute bronchial inflammation and oxidative stress, was measured first, using the portable analyzer. Then a portable spirometer was used to perform the forced expiratory measurements.PM2.5 exposure concentrations were 379.9±4.7 μg/m3 and 154.5±3.6 μg/m3 in welders and office workers, respectively. Welders had lower levels of NO in exhaled breath than that of office workers after adjusting for confounds, though the difference was not significant. Participants with current smoking habit had significant lower NO levels compared to non-smokers. Individual urinary metal such as Mn, Co, Ni, and Fe was associated with NO in exhaled breath in all workers after adjusting for confounds. However, only individual urinary Ni, or Fe metal was associated with NO in exhaled breath in welders. No association between any lung function indicators and NO level in exhaled breath was found.We concluded that some particular metals from metal fume particulate matter exposure may be associated with decreasing NO level in exhaled breath in welders.

Asymmetric dimethylarginine and angiogenesis: biological significance.

Competitive inhibition of endothelial nitric oxide synthase (eNOS) is the main biological effect of asymmetric dimethylarginine (ADMA), i.e. the methylated derivative of L-arginine. The resulting low level of NO is becoming one of the elements of pathogenesis of numerous cardiovascular disorders, mainly related to atherosclerosis, but also other metabolic diseases including type 2 diabetes. It appears that a high level of ADMA is not only a marker of pathological conditions such as chronic kidney failure, but also a significant factor which damages the endothelium. Despite multiple studies, the mechanisms of reducing the level of ADMA, which would allow to inhibit the progression of cardiovascular diseases and effective treatment, e.g. by means of L-arginine supplementation or medicines which are lowering ADMA levels, are still unclear. Perhaps, linking ADMA with the processes of new blood cell formation (angiogenesis) will allow us to explain these multifactor mechanisms.

The Australian Child Health and Air Pollution Study (ACHAPS): A national population-based cross-sectional study of long-term exposure to outdoor air pollution, asthma, and lung function

Most studies of long-term air pollution exposure and children's respiratory health have been performed in urban locations with moderate pollution levels. We assessed the effect of outdoor nitrogen dioxide (NO2), as a proxy for urban air pollution, on current asthma and lung function in Australia, a low-pollution setting.We undertook a national population-based cross-sectional study of children aged 7–11 years living in 12 Australian cities. We collected information on asthma symptoms from parents via questionnaire and measured children's lung function (forced expiratory volume in 1 s [FEV1], forced vital capacity [FVC]) and fractional exhaled nitric oxide [FeNO]). We estimated recent NO2 exposure (last 12 months) using monitors near each child's school, and used a satellite-based land-use regression (LUR) model to estimate NO2 at each child's school and home.Our analysis comprised 2630 children, among whom the prevalence of current asthma was 14.9%. Mean (±SD) NO2 exposure was 8.8 ppb (±3.2) and 8.8 ppb (±2.3) for monitor- and LUR-based estimates, respectively. Mean percent predicted post-bronchodilator FEV1 and FVC were 101.7% (±10.5) and 98.8% (±10.5), respectively. The geometric mean FeNO concentration was 9.4 ppb (±7.1).An IQR increase in NO2 (4.0 ppb) was significantly associated with increased odds of having current asthma; odds ratios (ORs) were 1.24 (95% CI: 1.08, 1.43) and 1.54 (95% CI: 1.26, 1.87) for monitor- and LUR-based estimates, respectively. Increased NO2 exposure was significantly associated with decreased percent predicted FEV1 (−1.35 percentage points [95% CI: −2.21, −0.49]) and FVC (−1.19 percentage points [95% CI: −2.04, −0.35], and an increase in FeNO of 71% (95% CI: 38%, 112%).Exposure to outdoor NO2 was associated with adverse respiratory health effects in this population-based sample of Australian children. The relatively low NO2 levels at which these effects were observed highlight the potential benefits of continuous exposure reduction.

MicroRNA Microarray-Based Identification of Involvement of miR-155 and miR-19a in Development of Oral Lichen Planus (OLP) by Modulating Th1/Th2 Balance via Targeting eNOS and Toll-Like Receptor 2 (TLR2).

BackgroundA wide range of microRNAs (miRNAs) have been shown to play a significant role in disease regulation. The objective of this study was to explore the role of miR-155 and miR-19a in the regulation of oral lichen planus (OLP).Material/MethodsMicroarray assay, real-time PCR, Western blot assay, computational analysis, luciferase assay, ELISA, and immunohistochemistry analysis were carried out to investigate the role of miR-155 and miR-19a in OLP.ResultsAccording to microarray assay and real-time PCR results, the expression of miR-155 was most significantly decreased among the 16 candidate miRNAs in the OLP group, whereas the expression of miR-19a was most significantly increased. MiR-155 and miR-19a directly targeted endothelial nitric oxide synthase (eNOS) and TLR2, respectively, since only the cells co-transfected with miR-155/wild-type eNOS 3′UTR or cells co-transfected with miR-19a/wild-type TLR2 3′UTR exhibited decreased luciferase activity. In addition, the expression of TLR2 was highly upregulated in OLP, whereas the expression of eNOS was significantly downregulated. A negative correlation was found between miR-19a and TLR2 mRNA, with a coefficient value of −0.40. Similarly, a negative correlation was found between miR-155 and eNOS mRNA, with a coefficient value of −0.54. A lower level of NO, IL-4, IL-5, and IL-10 was observed in OLP, which was also accompanied by a higher level of TNF-α and IFN-γ. Finally, the upregulation in miR-155 directly decreased the expression of eNOS and further inhibited the production of NO. Downregulation of miR-19a directly increased the expression of TLR2. The inhibition of NO production and the enhancement in TLR2 expression synergistically increased the production of TNF-α and IFN-γ, while decreasing the levels of IL-4, IL-5, and IL-10.ConclusionsIn this study, the peripheral blood mononuclear cells (PBMCs) from subjects with or without OLP were collected and their gene expression profiles were compared. It was found that OLP changed the expression profile of miR-155 and miR-19a, which in turn directly affected the production of eNOS and TLR2, respectively. In addition, by synergistically inducing an imbalance between Th1 and Th2, the simultaneous deregulation of miR-155/eNOS and miR-19a/TLR2 was responsible for an elevated risk of OLP.

Astraglaus polysaccharide protects diabetic cardiomyopathy by activating NRG1/ErbB pathway.

Diabetic cardiomyopathy (DCM) is one of the main cardiac complications among diabetic patients. According to previous studies, the pathogenesis of DCM is associated with oxidative stress, apoptosis and proliferation of local cardiac cells. It showed, NRG1 can improve the function of mitochondria, and thereby, increasing proliferation and decreasing apoptosis of cardiac muscle cell via ErbB/AKT signaling, also, exert antioxidative function. Besides, NRG1/ErbB pathway was impaired in the DCM model which suggested this signaling played key role in DCM. Astraglaus polysaccharide (APS), one of the active components of Astragalus mongholicus, showed striking antioxidative effect. Here, in this study, our data showed that APS can promote proliferation and decrease apoptosis in AGE-induced DCM cell model, besides, APS can decrease intracellular ROS level, increase activity of SOD, GSH-Px and lower level of MDA and NO in DCM cell model, indicating APS exerted antioxidative function in DCM model cells. Besides, western blot results revealed APS induced NRG1 expressing and the phosphorylation level of ErbB2/4. In addition, the elevated NRG1 promoted AKT and PI3k phosphorylation which indicated APS may exert its function by NRG1/ErbB and the downstream AKT/PI3K signaling. Canertinib is ErbB inhibitor. The effect of APS on proliferation, apoptosis, antioxidation and NRG1/ErbB pathway was partly abolished after the cells were co-treated with APS and canertinib. Taken together, these results suggested APS may display its protective function in DCM cells by activating NGR1/ErbB signaling pathway. And our study increased potential for prevention and therapy to DCM.

Long breathing lean NOx trap regeneration with supplemental n-butanol

This paper evaluates a long breathing strategy of lean NO x trap for achieving ultra-low nitrogen oxide (NO x) emissions, with an aim to reduce the associated fuel penalty. The fuel impacts on the long breathing strategy of lean NO x trap operation are examined on a heated flow bench with diesel and n-butanol as the reductants. Engine tests are performed to identify suitable working regions for the lean NO x trap strategies. For a very low engine-out NO x emission level of ~30 ppm, the long breathing adsorption of the lean NO x trap shows a significant improvement in NO x storage efficiency compared to a conventional lean NO x trap operational strategy for a moderate level of NO x emissions. The use of n-butanol fuel in diesel engines produces much lower NO x and particulate matter emissions, which is deemed advantageous for operating the long breathing lean NO x trap strategy. As a reductant for lean NO x trap regeneration, n-butanol is found to be more effective in terms of regeneration effectiveness, NO x conversion efficiency, and potential hydrogen (H2) yield compared to using diesel fuel in the after-treatment. A fuel penalty analysis is conducted for the selected cases with combinations of different combustion modes and lean NO x trap strategies. Given a low level of NO x emissions from n-butanol combustion, the long breathing lean NO x trap strategy can potentially achieve ultra-low NO x emissions with a minimum fuel penalty.

Mediation of inducible nitric oxide and immune-reactive lysozymes biosynthesis by eicosanoid and biogenic amines in flesh flies

AbstractNitric oxide (NO) plays various roles in insect immunity: as a cytotoxic component and as a signalling molecule; and immune-reactive lysozymes (IrLys) provide a first line of humoral immune functions against invading bacteria. Although there is considerable literature on eicosanoid and biogenic monoamine actions on insect immunity, there is no information on the role(s) of these chemicals in inducing NO and IrLys. We addressed this gap by challenging third instarSarcophaga(Liopygia)argyrostoma(Robineau-Desvoidy) with the Gram-positive bacteriumMicrococcus luteus. Here, we report that bacterial challenge induces elevation of NO and IrLys concentrations in haemocytes and in the fat body. The plasma pool content is comparatively low. Eicosanoid biosynthesis inhibitors (EBIs) lead to suppression of both NO and IrLys levels. Control larvae have low constitutive levels of NO and lysozyme concentrations. Octopamine (OA) elicits elevation of NO and IrLys concentrations. A similar effect is obtained by 5-hydroxytryptamine (5-HT) for NO. These data indicate immune-mediating roles of eicosanoids, OA and 5-HT in NO and IrLys activities.

Nasal Nitric Oxide Levels in HIV Infection: A Cross-Sectional Study.

Introduction Low levels of nasal NO have been associated with increased propensity to rhinosinusitis and respiratory tract infections. Our objective was to describe nasal NO levels in HIV-infected individuals versus healthy controls and determine possible risk factors for reduced nasal NO levels. Materials and Methods HIV-infected individuals and healthy controls were recruited. Participants underwent nasal NO testing by standardized methods using a CLD88 chemiluminescence analyzer and completed the Sinonasal Outcome Test-20 (SNOT-20) on symptoms of rhinosinusitis. Results Participants included 41 HIV-infected individuals with suppressed VL on antiretroviral therapy (ART group), 5 HIV-infected individuals with detectable VL off ART (viremic group), and 12 healthy controls (HC group). Mean nasal NO level was 253 (±77) nL/min in the ART group, 213 (±48) nL/min in the viremic group, and 289 (±68) nL/min in the HC group (p = 0.133; ANOVA). There was no correlation between nasal NO level and VL in viremic individuals (r = −0.200; p = 0.747). Differences were observed in mean total points on the SNOT-20 which were 19 (±16)/100, 18 (±26)/100, and 4 (±4)/100 in the ART, viremic, and HC groups, respectively (p = 0.013; ANOVA). Conclusion Healthy individuals, HIV patients on ART, and viremic individuals off ART display similar nasal NO levels. However, rhinosinusitis symptoms remain prominent despite ART-treatment.

Effect of total flavonoid in rabdosia rubescens on tolerant mice models under cerebral anoxia.

ObjectiveTo study the protective effect of total flavonoid in rabdosia rubescens on BIT model by brain ischemic tolerance (hereinafter BIT) model of mice.MethodBIT model is used to block bilateral common carotid arteries and to copy BIT model of mice. After 10 min of transient ischemia for rats in preconditioning group, the mice in the nimodipine group and naoluotong capsule group were given the total flavonoid in rabdosia rubescens (300 mg/kg, 150 mg/kg, 75 mg/kg) for gavage, sham operation group, ischemia/reperfusion injury (hereinafter IRI) group and BIT group were fed with the same volume of 0.5% sodium carboxymethyl cellulose (CMC) once a day for 5 days. After administration for 1 h on day 5 (120 h), the rats in the other groups except for the sham operation group were treated with blood flow block for 30 min and reperfusion for 22 h. The serum NSE level were measured and the brain NO content and NOS activity changes was measured to observe the histopathological changes of brain tissue.ResultsBIT models of mice and in rats were both successfully replicated. The total flavonoid in rabdosia rubescens can decrease the mortality of mice, decrease serum NSE level, increase the content of NO and the activity of NOS in the brain tissue of mice, and improve the pathological damage of cortex and hippocampus of mice.ConclusionThe total flavonoid in rabdosia rubescens can stimulate an endogenous protective mechanism by inducing the release of low levels of cytokines NO and NOS, which reduces the release of serum NSE, relieves the brain tissue ischemia-reperfusion injury, and further improves the protection effect of ischemic preconditioning on brain injury. The damage of brain tissue ischemia and reperfusion, and further improve the ischemia Protective effect of preconditioning on brain injury.

Components of human placental extract and its protective effect to rat from D-GalN induced acute liver injury

Objective: To evaluate the effect of human placental extracts (HPE) on the protection from acute liver injury (ALI) induced by D-GalN and analyze the components of HPE. Methods: (1)Fourty male mice were randomly divided into five groups (Blank, Model, MgIG, HPE and HPE+ MgIG) for the ALI model and treatments.The serum alanine aminotransferase (ALT) and aspartate transaminase (AST) were determined by biochemical assays.Nitric monoxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), total antioxidant capacity (T-AOC) in serum and hepatic tissue were detected by assay kits.The extent of liver damage was evaluated by histological examination.(2)Relative molecular mass of HPE was determined by SDS-PAGE.(3) Component identification was performed by using LCMS-TOF.(4)Selected functional molecules in HPE were detected by protein array. Results: (1) A lower level of NO and MDA and a higher SOD and T-AOC were observed in rats treated with HPE compared to the non-treated rats in an acute liver failure disease model.(2) The size of HPE was about 1 200-4 600 by electrophores.(3) 7 peaks of HPE were identified, including uracil, hypoxanthine, tyrosine, phenylalanine, tryptophan, xanthine and thymine.(4) Comparable high concentrations of TGF-β, IGF-1, IL-9, IL-29 and TNF-α of HPE were revealed by protein array. Conclusions: (1) HPE protects rat from liver damage induced by D-GalN. (2) HPE contains Uracil, hypoxanthine, xanthine, thymine, and functional proteins as TGF-β, IGF-1, IL-9, IL-29 and TNF-α.

Effect of reducing the methane concentration on the combustion and performance of a biogas diesel predominantly premixed charge compression ignition engine

In a biogas diesel predominantly premixed charge compression ignition (BDPPCCI) engine the effect of composition of biogas on combustion, performance and emissions was experimentally investigated. A twin cylinder automotive common rail engine with an open electronic control unit was run on one of its cylinders in this mode while the other cylinder was nonfunctional. Three biogas compositions with methane (CH4) proportions of 53–58% (as obtained from the plant), 67% and 22–25% were used at a constant engine speed of 1800rpm. Stable engine operation in the BDPPCCI mode even with very low methane fractions was possible without adverse effects on efficiency and emissions. Reducing the methane proportion (i.e. high proportion of CO2) enabled the brake mean effective pressure (BMEP) to be extended from 4bar to 5bar with sufficient margin for start of injection (SOI). Lower CH4 (i.e. increased CO2 proportion) also allowed the use of retarded SOI for diesel which resulted in reduced smoke emissions. This not only improved the combustion phasing but also lowered the peak heat release rate leaving the thermal efficiency relatively unaffected. Results indicate that extremely low levels of NO and smoke can be reached in the BDPPCCI mode at the best efficiency operating condition if the biogas composition is altered based on the output.

Co-Firing of Fast Pyrolysis Bio-Oil and Heavy Fuel Oil in a 300-kWth Furnace

Combustion characteristics and pollutant emissions of burning fast pyrolysis bio-oil/heavy fuel oil (HFO) blends in a 300-kWth furnace are investigated. Lauan (shorea) wood is used as biomass feedstock for making bio-oil via a fast pyrolysis process. The bio-oil has high viscosity, high water and oxygen content, as well as a low heating value. A furnace test is conducted for pure HFO and bio-oil/HFO blends with various mixing ratios. The results show that instability occurs during the test for cases with more than 5% bio-oil in the emulsion. Notably, it is verified that burning a bio-oil/HFO blend with a 2.5% bio-oil and a 97.5% HFO exhibits similar furnace performance and has lower NO and SO2 emission levels as compared to burning pure HFO. The reductions of NO and SO2 emissions are 2.6% and 7.9% for this blend, respectively.

Comparison of OMI NO<sub>2</sub> observations and their seasonal and weekly cycles with ground-based measurements in Helsinki

Abstract. We present the comparison of satellite-based OMI (Ozone Monitoring Instrument) NO2 products with ground-based observations in Helsinki. OMI NO2 total columns, available from NASA's standard product (SP) and KNMI DOMINO product, are compared with the measurements performed by the Pandora spectrometer in Helsinki in 2012. The relative difference between Pandora no. 21 and OMI SP total columns is 4 and −6 % for clear-sky and all-sky conditions, respectively. DOMINO NO2 retrievals showed slightly lower total columns with median differences about −5 and −14 % for clear-sky and all-sky conditions, respectively. Large differences often correspond to cloudy fall–winter days with solar zenith angles above 65°. Nevertheless, the differences remain within the retrieval uncertainties. The average difference values are likely the result of different factors partly canceling each other: the overestimation of the stratospheric columns causes a positive bias partly compensated by the limited spatial representativeness of the relatively coarse OMI pixel for sharp NO2 gradients. The comparison between Pandora and the new version (V3) of OMI NO2 retrievals shows a larger negative difference (about −30 %) than the current version (V2.1) because the revised spectral fitting procedure reduces the overestimation of the stratospheric column. The weekly and seasonal cycles from OMI, Pandora and NO2 surface concentrations are also compared. Both satellite- and ground-based data show a similar weekly cycle, with lower NO2 levels during the weekend compared to the weekdays as a result of reduced emissions from traffic and industrial activities. The seasonal cycle also shows a similar behavior, even though the results are affected by the fact that most of the data are available during spring–summer because of cloud cover in other seasons. This is one of few works in which OMI NO2 retrievals are evaluated in a urban site at high latitudes (60° N). Despite the city of Helsinki having relatively small pollution sources, OMI retrievals have proved to be able to describe air quality features and variability similar to surface observations. This adds confidence in using satellite observations for air quality monitoring also at high latitudes.

Ruthenium-Modified Sensitive NO Sensors: Quantifying Nitric Oxide in the Pathobiology of Cystic Fibrosis

This is a preliminary work towards preparing a device capable to measure nitric oxide levels in a cystic fibrosis cell line model. It has been found that exhaled NO levels remains unchanged or reduced in cystic fibrosis patients unlike other inflammatory lung diseases like asthma where it increases. However it is not clear whether the lower NO levels in cystic fibrosis correlate with lowered production of this metabolite in the bronchial epithelium. We will present preliminary results of our ruthenium oxide modified combined electrodes and how they can be applied to the study of cystic fibrosis at the cellular level. In this work, we explore the performance of combined reference/working electrodes modified with ruthenium oxide and Poly(3,4-ethylenedioxythiophene) (PEDOT) in the detection of nitric oxide with the goal to measure nitric oxide at the level of single or collective cultured cells. The synergistic effect of the electrocatalytic activity of ruthenium oxide and the enhanced surface area for catalytic activity provided by the polymer greatly enhanced the analytical performance of our sensors in terms of sensitivity, selectivity and stability. With the incorporation of a layer by layer method of electrodeposition we attained a normalized sensitivity of 8.38E-4 pA/nM/μM2 and 1.16E-2 pA/nM/μM2 towards NO in the linear range of 0.2-1.6 mM and 2-16 nM respectively, at an applied potential of 0.8 V vs Ag/AgCl and a detection limit in the vicinity of 500 pM. In order to improve the selectivity of our sensors we coated the surface with nafion and also an ionic liquid composite and lowered the applied to 0.6 V vs. Ag/AgCl. We also measured the response to NO using Differential Pulse Amperometry to further decrease response from biological interferents especially nitrite and ascorbic acid.

A space‐based, high‐resolution view of notable changes in urban NOx pollution around the world (2005–2014)

AbstractNitrogen oxides (NOx = NO + NO2) are produced during combustion processes and, thus may serve as a proxy for fossil fuel‐based energy usage and coemitted greenhouse gases and other pollutants. We use high‐resolution nitrogen dioxide (NO2) data from the Ozone Monitoring Instrument (OMI) to analyze changes in urban NO2 levels around the world from 2005 to 2014, finding complex heterogeneity in the changes. We discuss several potential factors that seem to determine these NOx changes. First, environmental regulations resulted in large decreases. The only large increases in the United States may be associated with three areas of intensive energy activity. Second, elevated NO2 levels were observed over many Asian, tropical, and subtropical cities that experienced rapid economic growth. Two of the largest increases occurred over recently expanded petrochemical complexes in Jamnagar (India) and Daesan (Korea). Third, pollution transport from China possibly influenced the Republic of Korea and Japan, diminishing the impact of local pollution controls. However, in China, there were large decreases over Beijing, Shanghai, and the Pearl River Delta, which were likely associated with local emission control efforts. Fourth, civil unrest and its effect on energy usage may have resulted in lower NO2 levels in Libya, Iraq, and Syria. Fifth, spatial heterogeneity within several megacities may reflect mixed efforts to cope with air quality degradation. We also show the potential of high‐resolution data for identifying NOx emission sources in regions with a complex mix of sources. Intensive monitoring of the world's tropical/subtropical megacities will remain a priority, as their populations and emissions of pollutants and greenhouse gases are expected to increase significantly.

Maternal plasma nitric oxide metabolites and cervical length assessment in predicting the tocolytic therapy in preterm labor in Isfahan.

Background:Preterm labor (PTL) is the main challenge in prenatal health care, leads to high rate of mortality and increases cost of health services. To evaluate the preterm delivery (PTD)-related risk factors, we decided to measure nitrite oxide metabolites and cervical length (CL) as the diagnostic and predictive tools for PTD in women and response to tocolytic therapy.Materials and Methods:In this case–control study, sixty women of 18–35 years with first pregnancy during the 24–34 gestational weeks with PTL in case group admitted to the delivery section of Beheshti Hospital, Isfahan, Iran were included. Sixty women in control group have the same specifications. NO and CL level were assessed, and the collected data were analyzed by SPSS software, version 20 and MedCalc software, version 15.1.Results:The two groups were similar regarding maternal and gestational age (P > 0.05). Lower level of NO was observed in PTL women with a mean of 35.30 ± 8.27 μmol/L compared to the normal gestation group with a mean of 39.05 ± 10.17 μmol/L (P = 0.035). In addition, the diagnostic accuracy of both PTL-predicting factors was determined (NO ≤31, sensitivity 99.7%, specificity 82.5% and CL ≤22, sensitivity 80%, specificity 99.9%).Conclusion:As the previous investigations stated, it can be claimed that NO might be the reliable marker for predicting the PTL, and administration of NO synthesis could be a candidate for the future therapeutic target.