Ppm Nitric Oxide Research Articles

High-Performance Nitric Oxide Gas Sensors Based on an Ultrathin Nanoporous Poly(3-hexylthiophene) Film.

Conjugated polymer (CP)-based organic field-effect transistors (OFETs) have been considered a potential sensor platform for detecting gas molecules because they can amplify sensing signals by controlling the gate voltage. However, these sensors exhibit significantly poorer oxidizing gas sensing performance than their inorganic counterparts. This paper presents a high-performance nitric oxide (NO) OFET sensor consisting of a poly(3-hexylthiophene) (P3HT) film with an ultrathin nanoporous structure. The ultrathin nonporous structure of the P3HT film was created via deposition through the shear-coating-assisted phase separation of polymer blends and selective solvent etching. The ultrathin nonporous structure of the P3HT film enhanced NO gas diffusion, adsorption, and desorption, resulting in the ultrathin nanoporous P3HT-film-based OFET gas sensor exhibiting significantly better sensing performance than pristine P3HT-film-based OFET sensors. Additionally, upon exposure to 10 ppm NO at room temperature, the nanoporous P3HT-film-based OFET gas sensor exhibited significantly better sensing performance (i.e., responsivity ≈ 42%, sensitivity ≈ 4.7% ppm-1, limit of detection ≈ 0.5 ppm, and response/recovery times ≈ 6.6/8.0 min) than the pristine P3HT-film-based OFET sensors.

Efficient nitric oxide sensing on nanostructured La2MMnO6 (M: Co, Cu, Zn) electrodes

Selective detection of nitric oxide (NO) is a challenge for automotive exhaust monitoring systems due to the instability of sensing architectures operating under extreme environments. Herein, yttria-stabilized zirconia (YSZ) solid-electrolyte-based electrochemical gas sensor was developed using double perovskite electrodes (DPO) for selective detection of NO. The La2MMnO6 (M: Co, Cu, Zn) phases were synthesized by sol-gel processing of constituent salts and characterized for physicochemical and sensing properties to investigate the impact of transition metal cations present in octahedral environments on charge transport properties. The La2ZnMnO6 with a predominant Zn2+–Mn4+ charge ordering excelled in the sensing characteristics with high sensitivity (33 mV/decade for 3–80 ppm NO concentration), fast response/recovery time (52/42 s) and significant NO selectivity at 500 °C. The sensing behavior of double perovskites was comprehensively explored and found to abide by the mixed-potential model. Moreover, stable sensing properties over a period of three weeks indicate the here-described sensors to be potentially competitive for onboard exhaust monitoring in automobiles.

Induction zone length measurements by laser-induced fluorescence of nitric oxide in hydrogen-air detonations

This experimental study aims at presenting a proof-of-concept for induction zone length (Δi) measurements in H2-air detonations by using the laser-induced fluorescence (LIF) of nitric oxide (NO) technique. The proof-of-concept is evidenced on a stoichiometric H2-air detonation, propagating in a mixture initially at 18 kPa and 293 K, by using an excitation wavelength at 225.120 nm and seeding the H2-air mixture with 1900 ppm of NO. Both, experiments in an optical detonation duct with a rectangular section and numerical simulations with an in-house code, KAT-LIF, are conducted. After verifying that the NO seeding has a negligible effect on the detonation structure, the main results are the following. A single correlation between the NO-LIF signal evolution and the Δi is determined numerically, based on the LIF signal decay at the end of the induction zone. The Δi measurements have a satisfactory 2% theoretical accuracy, determined from comparisons between Zeldovich-von Neumann-Döring (ZND) and KAT-LIF simulations, and a ±160−μm experimental uncertainty. An evolution of the induction zone length as a function of the cellular cycle is observed experimentally but, due to line of sight integrated chemiluminescence imaging of the detonation structure, a correlation between induction length and cellular cycle could not be achieved. However, statistical analysis of the results revealed that the evolution of the experimental induction lengths well correlates with the ZND and KAT-LIF simulations.

A single breath of nitric oxide does not alter pulmonary perfusion pressure.

What is the central question of this study? Is the amount of inhaled nitric oxide (NO) used during a diffusing capacity for inhaled NO manoeuvre sufficient to reduce pulmonary artery systolic pressure (PASP)? What is the main finding and its importance? These findings suggest that a single breath of inhaled NO does not change PASP, and combined with previous correlational work, further validates the use of the diffusing capacity for NO manoeuvre as a technique to determine pulmonary capillary blood volume and membrane diffusing capacity. The measurement of diffusing capacity is an important pulmonary function test to evaluate gas exchange. Using both carbon monoxide and nitric oxide (NO), the diffusing capacity for nitric oxide (DL,NO ) technique allows for the partitioning of capillary blood volume and membrane diffusing capacity. However, inhaled NO is known to dilate pulmonary arterioles in both health and disease and therefore could alter the outcomes that the DL,NO technique aims to quantify. The purpose of the study was to determine if a DL,NO manoeuvre alters pulmonary perfusion pressure. Nine participants completed 12 simulated 10-s breath-hold DL,NO manoeuvres (n=6 placebo inhalations and n=6 with 40ppm NO; order randomized) during which tricuspid regurgitant jet velocity was recorded continuously using Doppler ultrasound to estimate pulmonary artery systolic pressure (PASP) as a surrogate for pulmonary perfusion pressure. The PASP was not different between the placebo and NO conditions (P=0.742). These data indicate that a single DL,NO manoeuvre does not alter PASP and therefore would not be expected to acutely alter pulmonary capillary blood volume or membrane diffusing capacity.

Engineering CuMOF in TiO2 Nanochannels as Flexible Gas Sensor for High-Performance NO Detection at Room Temperature.

As a marker molecule in respiratory gases for the pulmonary disease asthma, nitric oxide (NO) has attracted much attention for real-time gas monitoring. However, low sensitivity, poor selectivity, and high operating temperature limit the practical applications of metal oxide semiconductor (MOS) based chemiresistor gas sensors. Herein, by deliberately introducing metal-organic frameworks (MOFs) in free-standing TiO2 nanochannels (NCs), a chemiresistor gas sensor with excellent detection ability and outstanding selective traits is developed for sensing NO at room temperature (RT). The precisely engineered Cu(II)-based MOF Cu-TCA (H3TCA = tricarboxytriphenyl amine) induces more active surface in the NCs, causing the buildup of CuTCA/TiO2 p-n heterojunctions that improve the sensing response at RT just via a simple UV irradiation (λ = 365 nm). Importantly, the specialized reductive reaction of Cu(II) by NO enables a remarkable selectivity toward NO analysis. Owing to the synergistic large active surface and chemical sensitization effects from Cu-TCA, the resulting Cu-TCA/TiO2 NCs show outstanding sensing performance; i.e., the response ((Rgas - Rair)/Rair) reaches 124% at 50 ppm of NO with a detection limit of 140 ppb at RT. In addition, the response time decreases to 25.6% if the system is subjected to UV irradiation. The as-formed sensing membrane is also demonstrated to be practically effective for flexible and wearable sensing devices for quantitative NO analysis. This study facilitates the use of MOFs to achieve synergistically enhanced selectivity and sensitivity to develop high-performance gas sensors.

Using biochar to control nitric oxide air pollution

This study deals with the ability of Rice Husk Biochar (RHB) to adsorb and reduce the concentration of 90 ppm Nitric Oxide (NO) gas which passed through it with a 1.2 liter/min flow rate within 8 minutes. The characteristics of biochar before and after adsorption were studied by SEM, EDAX, and FTIR analyses. To study the effect of different factors on adsorption the effect of manufacturing temperatures of biochar was studied by using two degrees 450 °C and 500 °C. It has also been measured the effect of biochar particles size using two types of size, coarse (C) and fine (F). The effect of the shape of the measurement system on the adsorption was also measured using two types of systems A and B. In general, the RHB450C A gives the best adsorption capacity for NO (95.7 mg/g) followed by RHB450F A (41.9 mg/g) followed by RHB500C A (24.8 mg/g). Both Langmuir and Freundlich isothermal models were applied to mathematical modelling of NO adsorption, and based on the coefficient of determination (r2) Langmuir’s model provided a perfect fit to the experimental data. It was also found that the pseudo-first-order model is suitable for studying adsorption kinetics.

Abstract 1283: Single intra-tumoral injection of gaseous nitric oxide induces an adaptive immune response in a mouse CT-26 solid tumor model

Abstract Background: Metastases are responsible for a significant portion of the morbidity and mortality in cancer patients. In situ destruction of tumor mass has been reported to provide the immune system with an antigen source for the induction of antitumor immunity, which can then attack distant metastases. Nitric oxide (NO) acts as a signaling molecule in multiple disease states, including cancer. NO has been shown to activate innate and adaptive responses of the immune system against tumors. In a previous Beyond Air study, 89% of CT26 tumor bearing mice treated with 50,000 parts per million (ppm) gaseous NO (gNO), rejected a secondary tumor induction. Here, we assessed the effects of a single intra-tumoral injection of gNO at concentrations of 20,000-50,000 ppm on immune cell recruitment in the tumor, spleen, and blood. Methods: Mouse colon carcinoma (CT26) tumor bearing Balb/c mice underwent a single intra-tumoral treatment with 20,000 (n=3) or 50,000 (n=4) ppm gNO for 5 minutes. Mice treated with N2 (n=3), under the same conditions, served as a control. Tumors were removed 14 days post treatment and were histologically analyzed to test for immune cell penetration, inflammation, and necrosis. Immune cells from the spleen and blood were harvested 21 days post treatment and assessed via flow cytometry. Results: 1. Treatment with 50,000 ppm gNO resulted in higher levels of inflammation, lymphocytes and T-cell infiltration, and necrosis within the tumor compared to both N2 and 20,000 ppm NO, as viewed histologically. 2. Flow cytometry analysis of immune cells from the spleen revealed a 1.3-fold increase of both B cells and IFN-γ expressing T cells with 50,000 NO treatment, and a 1.3-fold increase of B cells and 1.1-fold increase of IFN-γ expressing T cells with 20,000 NO treatment, compared to N2. 3. A 29% reduction of myeloid-derived suppressor cells (MDSCs) was detected in spleens of mice treated with 50,000 ppm gNO, and 40% for 20,000 ppm, compared to mice treated with N2. Conclusion: Intra-tumoral injection of ultra-high doses of NO at 20,000 and 50,000 ppm gNO led to an increased recruitment and concentration of T and B cells. Additionally, 50,000 ppm NO led to an increase of lymphocyte infiltration to the tumor. Taken together, the data suggest that the increase in lymphocyte infiltration, B and T cell population, and the reduction of MDSCs, are indicative of an adaptive immune response that results in rejection of secondary tumors in gNO-treated mice. Citation Format: Hila Confino, Matan Goldshtein, Yakir Levi, Lidor Malka, Amir Avniel, Steve Lisi, Ido Wolf. Single intra-tumoral injection of gaseous nitric oxide induces an adaptive immune response in a mouse CT-26 solid tumor model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1283.

Compact and Versatile QEPAS-Based Sensor Box for Simultaneous Detection of Methane and Infrared Absorber Gas Molecules in Ambient Air

In this work we report on an innovative sensor box employing two acoustic detection modules connected in series for quartz-enhanced photoacoustic multi-gas detection. One detection module is coupled with an internal distributed-feedback quantum cascade laser (DFB-QCL) emitting at ∼7.719 µm for methane (CH4) sensing, while the second module has been designed to be coupled with an external laser source targeting the absorption features of a specific gas molecule Mx in the infrared spectral range. The sensor box can thus be employed for any application, depending on the CH4/Mx gas combination to be detected. The ∼7.719 µm DFB-QCL also allowed water vapor monitoring. To demonstrate the sensor versatility, we report on the QEPAS-box environmental monitoring application by simultaneously detecting in air methane, which is a greenhouse gas, nitric oxide (NO), an ozone depleting substance, and water vapor. Sensitivity levels of 4.30 mV ppm−1 and 17.51 mV ppm−1 and minimum detection limits of 48 ppb and 11 ppb for methane and nitric oxide detection were achieved, respectively. The sensor box operation was tested by analysing ambient air. Average concentrations of ∼1.73 ppm of CH4, ∼0.134 ppm of NO and 1.8% of H2O were measured.

The effect of the addition of nitrogen oxides on the oxidation of ethane: An experimental and modelling study

This study reports new ignition delay time (IDT) measurements of ethane (C2H6)/‘air’ mixtures with NOx (nitric oxide (NO), nitrogen dioxide (NO2), and nitrous oxide (N2O)) addition in the range 0 – 1000 ppm at stoichiometric fuel to air (φ) ratios, at compressed temperatures (TC) of 851 – 1390 K and at compressed pressures (pC) of 20 – 30 bar. In addition, new IDT measurements of three highly diluted C2H6/NO2 mixtures at φ = 0.5, TC = 805 – 1038 K, and pC = 20 – 30 bar are also studied. These new experimental data, together with data already available in the literature, are used to validate NUIGMech1.2 with an updated NOx sub-mechanism. Although the addition of 200 ppm of NO or NO2 to ethane shows a minimal promoting effect, the addition of 1000 ppm significantly promotes its reactivity. The similarity of the effect of the addition of both NO and NO2 addition is due to the fast conversion of NO into NO2 in the presence of molecular oxygen. However, the 1000 ppm NO doped ethane mixtures exhibit ∼20% shorter IDTs compared to the NO2 blended ones. The addition of 1000 ppm of N2O exhibits no effect on ethane oxidation at the conditions studied. The NUIGMech1.2 predictions can reproduce the sensitisation effect of NOx on ethane with good agreement over a wide range of pressure, temperature, equivalence ratio, and percentage dilution. Sensitivity and flux analyses of C2H6/NOx are performed to highlight the key reactions controlling ignition over the different temperature regimes studied. The analyses show that there is a competition between the reactions Ṙ + NO2 ↔ RȮ + NO and Ṙ + NO2 (+M) ↔ RNO2 (+M). This governs NOx sensitization on C2H6 ignition.

Graphene quantum dots/carbon nitride heterojunction with enhanced visible-light driven photocatalysis of nitric oxide: An experimental and DFT study

Visible light-driven photocatalysis for the degradation of nitric oxide (NO) has attracted considerable attention. Graphene quantum dots/graphite phase carbon nitride (GQDs/CN) heterojunctions were proposed as efficient visible-light responsive photocatalysts for NO treatment under the guidance of density function theory (DFT) simulation. Then, the GQDs/CN was synthesized via hydrothermal combination of GQDs and g-C3N4 (CN) produced from pyrolysis of citric acid (CA) and melamine, respectively. Afterwards, the GQDs/CN composite samples were characterized using XRD, XPS, FE-SEM, TEM, HR-TEM, BET, UV–Vis DRS, PL, photocurrent tests, and EIS. Later, the photocatalytic activity of the prepared GQDs/CN composites was evaluated by degrading NO at ppm level under visible light irradiation at conditions of 20 ppm of NO, 5% of O2, and 50% of relative humidity. Results show that 9GQDs/CN outperforms its counterparts. Compared to CN, the 9GQDs/CN increases the NO conversion rate from 61% to 90%, the selectivity of nitrate formation from 53% to 74%, and the value of DeNOx index from −0.25 to 0.19. The enhanced performance results from the inclusion of GQDs, which increases the specific surface area, promotes the absorption of light, boosts the separation of photogenerated electrons and holes, and inhibits their recombination. Furthermore, we used active species detection experiment, IC, in-situ DRIFTS, ESR measurement, XPS VB, Mott-Schottky, and DFT calculations to systematically explore the mechanism behind the degradation of NO using GQDs/CN, and confirmed the formation of Type-Ⅱ heterojunction between GQDs and g-C3N4. In addition, 9GQDs/CN maintains a high NO conversion rate after 5 cycles of experiments, indicating its potential in industrial applications.

High-temperature NO sensing performance of WO3 deposited by spray coating.

Nitric oxide (NO) selective sensors capable of sensing in a hot-gas environment are increasingly required for monitoring combustion and processes yielding high temperature gas containing NO. This work reports the fabrication of sensors by a facile deposition of water-based ink blended commercial WO3 powders via spray coating on sensor platforms fitted with Au-interdigitated electrodes (IDEs) and the characterization of their sensing performances under hot NO-containing air at temperatures exceeding 500 °C. After deposition and heat treatment of the sensing material on the substrate fitted with Au-IDE at 700 °C, the composition and morphology of the active material were analyzed and the presence of a single phase, fine particulates of WO3, has been confirmed by XRD and SEM, respectively. The investigation of the sensing properties revealed that, contrary to the previous reports, this WO3 sensor can detect NO with a good sensitivity (∼22% for 200 ppm NO) and selectivity at 700 °C under humidity. The effect of relative humidity on sensing performance was also investigated. Also, under humidity values as high as 10% RH and at gas temperatures as high as 700 °C, a reasonably good sensor performance has been observed. It is likely that the improved response towards NO at moderately elevated temperatures resulted from the humidity related water molecules which are adsorbed on the surfaces of WO3 particles, providing high affinity hydrogen bonds between NO and OH.

Inhaled Nitric Oxide: In Vitro Analysis of Continuous Flow Noninvasive Delivery via Nasal Cannula.

Inhaled nitric oxide (NO) is most frequently delivered to mechanically ventilated patients in critical care, but it can also be administered noninvasively. The delivered dose and efficiency of continuous flow NO supplied through a nasal cannula has yet to be established. This study aimed to determine the influence of nasal cannula type, supply flow, and breathing pattern on delivered NO using a realistic adult airway replica and lung simulator. Simulated breathing patterns were selected to represent rest, sleep, and light exercise, and were varied to investigate the effects of tidal volume and breathing frequency independently. Supplied gas flows targeted tracheal concentrations at rest of 5 or 20 ppm NO and were supplied with 2 L/min O2. Three different cannulas were tested. Tracheal NO concentrations and NO mass flow past the trachea were evaluated. Cannula type had a minor influence on delivered dose. Tracheal NO concentrations differed significantly based on breathing pattern (P < 0.01); for a target NO concentration of 20 ppm at rest, average inhaled NO concentrations were 23.3 ± 0.5 ppm, 36.5 ± 1.4 ppm, and 17.2 ± 0.3 ppm for the rest, sleep, and light exercise breathing patterns, respectively. For the same test conditions, mass flow of NO past the trachea was less sensitive to breathing pattern: 20.3 ± 0.5 mg/h, 19.9 ± 0.8 mg/h, and 24.3 ± 0.4 mg/h for the rest, sleep, and light exercise breathing patterns, respectively. Mass flow and delivery efficiency increased when minute volume increased. These results indicate that inhaled NO concentration is strongly influenced by breathing pattern, whereas inhaled NO mass flow is not. NO mass flow may therefore be a useful dose metric for continuous flow delivery via nasal cannula.

Design and study of nitric oxide portable producing device using continuous discharging arc plasma reaction keeping low energy efficiency for viral pneumonia emergency therapy.

This study investigated the efficiency of a portable nitric oxide (NO) inhalation device through optimizing its design and structure. The portable rescue device could be used in clinical applications in outbreaks of viral pneumonia such as SARS. To reduce energy consumption for battery-powered portable usage, NO micro-channel plasma reactions induced by a continuous discharge arc were employed. A single-use airway tube could be combined with an intubation tube in clinical applications. In the experiment, a switching transistor controlled high frequency DC (12.5 kHz) was used to create a continuous discharge arc between two stainless steel electrodes (1-mm separation) after high-voltage breakthrough. A rotate instrument was employed to change the direction angle between the airflow and discharge arc, tube filled with Calcium hydroxide connected with gas outlet for reducing NO2, gas flow rate and input voltage were evaluated separately with concentration of NO and NO2/NO ratio. Results showed that a 2 L/min air flow direction from the cathode to the anode of electrodes (direction angle was zero) under 4 V input voltages produced 32.5±3.8 ppm NO, and the NO2/NO ratio reduced to less than 10%, stable output of nitric oxide might be convenient and effective for NO inhalation therapy. Modularization of the design produced a portable NO inhalation device that has potential for use in clinical applications as it is low cost, easy to disinfect, consumes low levels of energy and is ready to use.

Simultaneous Removal of NO and SO2 with a Novel Oxidation-Absorption Process Based on Air Microbubble Water System

Microbubbles (MBs) can spontaneously generate hydroxyl radicals (·OH) with high oxidizing capacity. In this study, a novel oxidation-absorption process based on a microbubble system in the indirect removal mode was proposed for the simultaneous removal of nitric oxide (NO) and sulfur dioxide (SO2). In this process, an air microbubble water system (AMBW) was produced by a microbubble generator (MBG) inhaling air and tap water and injected into an oxidation-absorption column reactor by the MBG, meanwhile the mixed gas composed of NO and SO2 passed through a micron-sized gas distributor at the bottom of the reactor and flowed into the AMBW. Important parameters including initial pH and temperature of tap water, operation time, NO concentration, SO2 concentration, and NaCl concentration were assessed to investigate the feasibility of the AMBW for the simultaneous removal of NO and SO2. The results showed that ·OH generated from the collapsed MBs played a critical role in the removal and the simultaneous removal of NO and SO2 was successfully achieved with the AMBW. Even with only tap water used as the absorbent, the removal efficiencies of NO and SO2 reached 92.7% and above 99%, respectively, when the experiment conditions were initial water pH 11.5, initial water temperature 298 K, 600 ppm NO, and 3,000 ppm SO2. Compared with the microbubble system in the direct removal mode, this new system is more suitable for the treatment of flue gases with low NO concentration and high volume. Moreover, this novel process should have a good prospect of industrial application in the flue gas treatment due to its high efficiencies of desulfurization and denitration and some advantages such as low usage cost of the reagents, simple system, and small occupation space.

NOx Gas Sensing Properties of Fe-Doped ZnO Nanoparticles

Herein, NOx, i.e., nitric oxide (NO) and nitrogen dioxide (NO2), gas sensors were fabricated using iron (Fe)-doped ZnO nanoparticles prepared via the facile hydrothermal process. The synthesized Fe-doped ZnO nanoparticles were analyzed through several techniques that revealed the well-crystallinity and dense growth of nanoparticles with the typical diameters of 25 ± 5 nm. The synthesized nanoparticles were utilized as a prospective material for the fabrication of NOx gas sensors operating at different temperatures, i.e., 350 °C, 400 °C, and 450 °C. The detailed sensing performances revealed that the optimum and most suitable sensing temperature for the fabricated sensors is 400 °C. In presence of 10 ppm NO gas, the fabricated sensor exhibited the highest gas response of 1.35 with a response (tresponse) and recovery (trecovery) time of 44 s and 402 s, respectively. Similarly, the fabricated NO2 gas sensor, in presence of 10 ppm gas shows the highest gas response of 1.33 with a response and recovery times of 50 s and 281 s, respectively. The presented results demonstrate that Fe-doped ZnO nanomaterials are capable to fabricate efficient NOx gas sensors.

Inhaled nitric oxide to control platelet hyper-reactivity in patients with acute submassive pulmonary embolism

BackgroundWe test if inhaled nitric oxide (NO) attenuates platelet functional and metabolic hyper-reactivity in subjects with submassive pulmonary embolism (PE). MethodsParticipants with PE were randomized to either 50 ppm NO + O2 or O2 only for 24 h with blood sampling at enrollment and after treatment; results were compared with healthy controls. Platelet metabolic activity was assessed by oxygen consumption (basal and uncoupled) and reactivity was assessed with agonist-stimulated thromboelastography (TEG) and fluorometric measurement of agonist-stimulated cytosolic [Ca++] without and with pharmacological soluble guanylate (sGC) modulation. ResultsParticipants (N = 38 per group) were well-matched at enrollment for PE severity, comorbidities as well as TEG parameters and platelet O2 consumption. NO treatment doubled the mean plasma [NO3-] (P < 0.001) indicating successful delivery, but placebo treatment produced no change. After 24 h, neither TEG nor O2 consumption parameters differed significantly between treatment groups. Platelet cytosolic [Ca++] was elevated with PE versus controls, and was decreased by treatment with cinaciguat (an sGC activator), but not riociguat (an sGC stimulator). Stimulated platelet lysate sGC activity was increased with PE compared with controls. ConclusionsIn patients with acute submassive PE, despite evidence of adequate drug delivery, inhaled NO had no major effect on platelet O2 consumption or agonist-stimulated parameters on TEG. Pharmacological activation, but not stimulation, of sGC effectively decreased platelet cytosolic [Ca++], and platelet sGC activity was increased with PE, confirming the viability of sGC as a therapeutic target.

La0.75Sr0.25Cr0.5Mn0.5O3-δ-Ce0.8Sm0.2O1.9 as composite electrodes in symmetric solid electrolyte cells for electrochemical removal of nitric oxide

Symmetric solid electrolyte cells with La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCM)-Ce0.8Sm0.2O1.9 (SDC) composite electrodes are employed for nitric oxide (NO) removal. The LSCM powders are synthesized and the cells with LSCM-SDC composite electrodes are fabricated successfully. The results show that moderate SDC addition in LSCM electrode improves the cell performance due to the expansion of three phase boundaries (TPBs). The electrode with 30 wt% SDC has the highest NO conversion of 69.2% and the lowest polarization resistance at 750 °C in 1000 ppm NO. The cathodic polarization activates the cathode because of the Cr/Mn ions reduction, more surface oxygen vacancies and Cr metal exsolution. The cell has good tolerances for H2O, CO2, and SO2, but excess O2 competes with NO for TPBs seriously. The sufficient stability and flexible operation mode of the cell are also proved. Finally, the NO adsorption mechanism on LSCM surface is revealed by density functional theory (DFT) calculations.

Nitric Oxide Attenuates the Inflammatory Effects of Air During Extracorporeal Circulation.

Cardiopulmonary bypass causes a systemic inflammatory response reaction that may contribute to postoperative complications. One cause relates to the air/blood interface from the extracorporeal circuit. The modulatory effects of blending nitric oxide (NO) gas into the ventilation/sweep gas of the membrane lung was studied in a porcine model of air-induced inflammation in which NO gas was added and compared with controls with or without an air/blood interface. Healthy swine were supported on partial bypass under four different test conditions. Group 1: no air exposure, group 2: air alone, group 3: air plus 50 ppm NO, and group 4: air plus 500 ppm NO. The NO gas was blended into the ventilation/sweep site of the membrane lung. The platelets and leucocytes were activated by air alone. Addition of NO to the sweep gas attenuated the inflammatory response created by the air/blood interface in this model.

The Effects of Nitric Oxide in Oxygenator Sweep Gas During Extracorporeal Circulation in a Neonatal Ovine Model.

Extracorporeal membrane oxygenation is a life-saving intervention, but bleeding complications are frequent. Given that the combination of platelet loss and dysfunction is a major contributor to this acquired bleeding diathesis, efforts to combat these phenomena are of great clinical importance. In this study, we investigated the effects of nitric oxide (NO) added to the sweep gas of an extracorporeal circuit in a neonatal ovine model. Eight lambs (age 9.6 ± 1.9 days) were cannulated via the neck vessels and maintained on a pumpless arteriovenous extracorporeal membrane oxygenation circuit with blood flow restricted to 100 ml/min for 72 hours. All animals were heparinized, and a subset (n = 4) also received NO in the sweep gas at a concentration of 200 ppm. We observed no adverse effects from NO administration, and methemoglobin levels remained unchanged. Platelet counts significantly declined in all animals over the course of the study; however, mean counts were higher in the NO-treated group, and this difference was statistically significant at 24 hours (62 ± 3% vs. 32 ± 7% of baseline, P < 0.01). Likewise, mean plasma levels of beta-thromboglobulin, a marker of platelet activation, were lower in the NO-treated group, and this difference was also significant at the 24 hour time point (9.5 ± 2.2 vs. 19.7 ± 6.5 pg/mL/10 platelets, P < 0.05). We conclude that 200 ppm NO can be safely blended into the oxygenator sweep gas of a low-flow extracorporeal circuit and that it may transiently attenuate platelet consumption and activation.

Protocol of a randomised controlled trial in cardiac surgical patients with endothelial dysfunction aimed to prevent postoperative acute kidney injury by administering nitric oxide gas

IntroductionPostoperative acute kidney injury (AKI) is a common complication in cardiac surgery. Levels of intravascular haemolysis are strongly associated with postoperative AKI and with prolonged (>90 min) use of cardiopulmonary...