Oxide Gas Research Articles

Collaborative performance of enzymatic saccharification and organic pollutant degradation from PHP (phosphoric acid coupled with hydrogen peroxide) pretreatment of lignocellulose.

As a newly developed technology, lignocellulose pretreatment of PHP (phosphoric acid coupled with hydrogen peroxide) can facilitate the enzymatic hydrolysis of pretreated lignocellulose for glucose production. It also has been found that the derived oxidative tail gas from pretreatment can facilely degrade organic pollutant. To balance the pollutant degradation and the glucose yield, the collaborative optimization on pretreatment was investigated. Results indicated that temperature, H3PO4 and H2O2 concentration were positively correlated with the model pollutant degradation (methylene blue) and enzymatic hydrolysis. Under the optimized conditions of temperature (55°C), H3PO4 concentration (65%), and H2O2 concentration (7%), three typical agricultural residues, including wheat straw, Jerusalem artichoke stalks and corn stover, achieved 95.2%, 94.0% and 98.3% methylene blue degradation, and the corresponding cellulose-glucose conversion was 100%, 97.6% and 100.0%, respectively. While two typical woody residues of oak and birch sawdust achieved methylene blue degradation of 70.2% and 68.0%, and the corresponding cellulose-glucose conversion reached 88.3% and 84.0%, respectively. 90.2-93.6% H3PO4 could be recovered with a stable performance of methylene blue degradation of 98.8-99.7% and cellulose-glucose conversion of 96.1-99.8% in the 5 recycling batches. Overall, this work achieved the "win-win" function on pollutant removal and glucose production, and efficient solvent recycling, which further improved the applicability of PHP pretreatment.

Multigas Identification by Temperature-Modulated Operation of a Single Anodic Aluminum Oxide Gas Sensor Platform and Deep Learning Algorithm.

Semiconductor metal oxide (SMO) gas sensors are gaining prominence owing to their high sensitivity, rapid response, and cost-effectiveness. These sensors detect changes in resistance resulting from oxidation-reduction reactions with target gases, responding to a variety of gases simultaneously. However, their inherent limitations lie in selectivity. Despite attempts to address this through new sensing materials and filters, achieving perfect selectivity remains challenging. This study addresses the selectivity issue by implementing temperature-modulated operation of a single SMO gas sensor utilizing an anodic aluminum oxide (AAO) microheater platform. The AAO-based sensor ensures a high thermal and mechanical stability during prolonged temperature modulation. A staircase waveform featuring six temperature conditions was applied to the microheater platform, and gas response data were collected for acetone, ammonia, ethanol, and nitrogen dioxide. Leveraging a convolutional neural network (CNN), gas patterns were trained and used to predict gas types and concentrations. The results demonstrated a high classification accuracy of 97.0%, with mean absolute percentage errors (MAPE) for concentration estimation of acetone, ammonia, ethanol, and nitrogen dioxide at 13.7, 19.2, 19.8, and 19.4%, respectively. The proposed method effectively classified four spices and accurately distinguished similar odors, which are difficult for human olfaction to differentiate. The results highlight that the combination of temperature modulation and deep learning algorithms proves to be highly effective in precisely determining gas types and concentrations.

Unraveling the Meaning of Effective Uptake Coefficients in Multiphase and Aerosol Chemistry.

ConspectusReactions of gas phase molecules with surfaces play key roles in atmospheric and environmental chemistry. Reactive uptake coefficients (γ), the fraction of gas-surface collisions that yield a reaction, are used to quantify the kinetics in these heterogeneous and multiphase systems. Unlike rate coefficients for homogeneous gas- or liquid-phase reactions, uptake coefficients are system- and observation-dependent quantities that depend upon a multitude of underlying elementary steps. As such, uptake coefficients adopt complex scaling behavior with reactant concentrations and other physicochemical properties of the interface, making predictions of γ particularly challenging.Typically, γgas is obtained by measuring the loss rate of a gas-phase molecule above a liquid or solid surface, relative to its collision frequency. By definition, γgas ≤ 1. Highly efficient reactions proceed at or near the gas-surface collision frequency and exhibit values of γgas near unity. Alternatively, heterogeneous kinetics are often measured using the consumption rate of a condensed phase reactant normalized to the gas-surface collision frequency, yielding instead an effective uptake coefficient (γeff). In many cases, γeff and γgas are not equal, yielding additional insights into the nature of the reaction. For example, substantial diffusive limitations in the condensed phase may inhibit reactivity, yielding γeff ≪ γgas. In contrast, γeff > γgas in the presence of condensed phase secondary reactions, with values of γeff often exceeding 1 for the case of radical chain reactions.In this Account, we will discuss how measurements of γeff in aerosol can uniquely reveal the origins of complex physical and chemical behavior in multiphase reactions under laboratory conditions. For example, measurements of the scaling of γeff with shell thickness during the ozonolysis of core-shell aerosol yields insight into the relative transport and reaction time scales of gaseous oxidants, while measurements of γeff, as a function of relative humidity (RH) during OH radical oxidation of hygroscopic citric acid aerosol, highlight the role that mixing times of particle-phase reactants play in determining aerosol reaction kinetics. Additionally, the scaling of γeff with oxidant and trace gas concentrations during the oxidation of long-chain hydrocarbons in aerosols by OH radicals and chlorine atoms provides distinctive signatures of the underlying competition between free radical propagation and termination mechanisms. Finally, it is shown how changes in γeff that are induced by careful selection of the molecular structure of the particle-phase reactant help to identify new reaction pathways, such as alternative mechanisms for lipid peroxidation, and to report on the reaction kinetics of short-lived reactive species, including Criegee Intermediates. Together, these examples will demonstrate how proper experimental design and accurate measurements of an effective uptake coefficient can be used to interrogate the fundamental steps governing complex multiphase reaction mechanisms.

Recent Developments in the Design of Photoactivated Metal Oxide Gas Sensors and Application of Plasmonic Nanoparticles in Hydrogen‐Sensing Devices

Recent Developments in the Design of Photoactivated Metal Oxide Gas Sensors and Application of Plasmonic Nanoparticles in Hydrogen‐Sensing Devices

Microbial changing patterns across lateral and vertical horizons in recently formed permafrost after the outburst of Zonag Lake, Tibetan Plateau.

In polar and alpine regions, global warming and landform changes are draining lakes, transforming them into permafrost with altered microbial communities and element cycling. In this study, we investigated bacterial and archaeal (prokaryotic) community changes in the newly exposed sediment of Zonag Lake (Tibetan Plateau), focusing on prokaryotic diversity, community structure, and genes involved in carbon fixation and nitrogen cycling across lateral (up to 800m) and vertical (up to 80cm) horizons. The results showed that prokaryotic richness decreased across the lateral horizons, coinciding with reductions in carbon concentrations. Dramatic changes in community structure changes were also observed, primarily influenced by the distance from the lake and then by sediment depth, with environmental filtering and dispersal limitations shaping the lateral and vertical distributions, respectively. Based on PICRUSt2 results, the relative abundance of genes related to carbon fixation increased along the lateral horizon, suggesting that microbial carbon fixers are counteracting the carbon loss during permafrost formation. In contrast, the genes related to denitrification also increased, which may lead to nitrogen loss and contribute to global warming by releasing nitric oxide gas. This study highlights the resilience of prokaryotic communities in drained lake basins and their ecological implications under global warming.

The effectiveness of prolonged hypothermic preservation of isolated rat hearts using oxygen, medical nitrous oxide and carbon monoxide gas mixtures.

The possibility of using an oxygen-nitrous oxide mixture for prolonged hypothermic preservation of rat heart for 24h was investigated. A comparative analysis of restoration of functional activity of hearts in the groups of 24-h preservation at +4°C with different gases (O2, N2) and gas mixtures (CO+O2, N2O+O2, N2+O2, N2O+N2) was carried out. It was shown that the presence of oxygen in the gas mixture was the key factor for heart preservation. No stable heart preservation was observed in oxygen-free mixtures. At the same time, preservation in pure oxygen showed a significantly lower level of cardiac recovery compared to preservation in gas mixtures O2+CO (6.5 atm.) and O2+N2O (6.5 atm.). LVDP (left ventricular developed pressure) values were 30±19mmHg and 46±9mmHg, respectively, with no significant differences found. The decrease in LDVP after 24h of storage was 26-40% of the intact control. The results obtained indicate the presence of pronounced synergistic effects of both gases during 24-h heart preservation, which is confirmed by data of marker genes Nfe2l2, Nox1, Prdx1, Hif1a, Nos2, Slc2a4, Ucp-1, Jun, Casp3 expression analysis and myocardial infarction damage level data. The more frequent occurrence of arrhythmias was observed in the oxygen-nitrous oxide group compared with the CO group, and the mechanism of this phenomenon is unclear. Nevertheless, the already medically approved N2O+O2 gas mixture could serve as a balanced choice for future improvements, offering a shorter duration of cardiac preservation compared to the CO+O2 mixture, while ensuring safety in its use.

Characteristics of low-temperature oxidative heating and gas production in coal storage under forced convection: Influencing factors and mechanisms.

Slow oxidation of coal during storage and transportation poses significant risks, making it essential to identify hot spots and understand the heat generation and gas production patterns in coal stockpiles. This study leverages the advantages of adiabatic oxidation experiments, which account for time effects, to accurately describe the low-temperature oxidation process of coal through warming and gas production dimensions. Additionally, the warming and gas production patterns of three-dimensional coal stockpiles with varying stacking parameters were investigated. The results indicate that activation energy for heat generation increases linearly with particle size. In anthracite and bituminous coals, the activation energy for gas production was lower than that for heat generation below 70°C, but higher above 70°C. Lignite showed a general trend of lower activation energy for heat generation compared to gas production. Under forced convection, airflow paths within the three-dimension coal stockpile became more complex, resulting in 3 distinct flow patterns. As external wind speed increased, the dominant factor in coal oxidation shifted from oxygen concentration control to heat dissipation control. Maintaining porosity below 0.15, particle size under 5mm, height under 8m, and slope angle below 40° can effectively delay the oxidation process. The factors influencing coal storage efficiency, ranked by importance, are wind speed, porosity, geometry, and particle size. This study offers theoretical insights for optimizing coal storage and transportation processes.

Preliminary mechanistic insights into the detection of ethanol vapour using MnO2 NRs-CNPs-poly-4-(vinylpyridine) based solid-state sensor operating at room temperature.

Semiconductor metal oxide gas sensors are widely used to detect ethanol vapours, commonly used in industrial productions, road safety detection, and solvent production; however, they operate at extremely high temperatures. In this work, we present manganese dioxide nanorods (MnO2 NRs) prepared via hydrothermal synthetic route, carbon soot (CNPs) prepared via pyrolysis of lighthouse candle, and poly-4-vinylpyridine (P4VP) composite for the detection of ethanol vapour at room temperature. MnO2, CNPs, P4VP, and MnO2 NRs-CNPs-P4VP composite were characterised using scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. Five sensors were prepared, namely, sensor 1 (MnO2 -NRs), sensor 2 (CNPs), sensor 3 (CNPs-P4VP composite of a mass ratio of 1:3), sensor 4 (MnO2 NRs-CNPs-P4VP composite of a mass ratio 1:1:3), and sensor 5 (MnO2 NRs-CNPs-P4VP composite of a mass ratio 2:1:3). All the five sensors were used detect to 2-propanol, acetone, ethanol, methanol, and mesitylene vapours at room temperature, but among all the tested sensors, sensor 4 was highly sensitive to ethanol vapour and less sensitive to 2-propanol, methanol, acetone, and mesitylene vapours. The response and recovery time of sensor 4 towards ethanol vapour at 20.4ppm were 82seconds and 74seconds, respectively. The limit of detection on ethanol vapour using sensor 4 was 789ppb. During detection, the ethanol vapour undergoes total deep oxidation on the surface of sensor 4.

Enhancing Nitric Oxide Gas Detection by Tuning the Structural Dimension of Electrospun ZnO Nanofibers Fibers and Polymers

Enhancing Nitric Oxide Gas Detection by Tuning the Structural Dimension of Electrospun ZnO Nanofibers Fibers and Polymers

Engineering Mild-Photothermal Responsive and NO Donor Prussian Blue Nanozymes Using Mild Synthesis for Inflammation Regulation and Bacterial Eradication in Periodontal Disease.

Periodontitis, an infectious disease of periodontal tissues caused by oral bacterial biofilms, is characterized by reactive oxygen species (ROS) accumulation and immune microenvironment imbalance. Multifunctional nanozymes, leveraging their physiochemical properties and enzymatic activities, offer promising antibacterial and anti-inflammatory strategies for managing periodontitis. In particular, Prussian blue nanozymes (PBzymes) exhibit exceptional ROS control due to their robust catalytic activity, diverse antioxidant functions, and high biocompatibility. However, the practical application of traditional high-temperature synthesis methods is limited. This study introduces a class of metal-engineered PBzymes synthesized at room temperature, identified for their potent antioxidative activity and excellent photothermal performance at mild temperatures. Nitric oxide (NO) gas therapy offers promising strategies for targeting deep infections in periodontal tissues. Thus, sodium nitroprusside is introduced into PBzyme to create SPBzyme via an in situ loading method. NO release by SPBzyme enhances antibacterial effects and overcomes resistance linked to bacterial biofilms, resulting in mild-photothermal antibacterial properties and synergistic antioxidant effects. In vitro antibacterial assays demonstrate the superior efficacy of SPBzyme under mild temperature conditions and near-infrared light exposure. Furthermore, SPBzyme effectively reduces inflammation and has positive therapeutic effects in periodontal animal models. Overall, mild-temperature photothermal NO release nanozyme therapy represents a novel approach for treating periodontitis.

Ro-Vibrational Spectrum of Vanadium Monoxide (VO) at 10 μm.

The high resolution ro-vibrational spectrum of the diatomic molecule vanadium oxide (VO) in the gas phase was measured around 1000 cm-1. In total, 1529 ro-vibrational transitions were assigned, in a spectral range of 984-1036 cm-1. For many transitions, the hyperfine structure resulting from the nuclear spin of 51V were resolved and the molecular parameters for the first (v = 1) and second (v = 2) excited vibrational state of VO were derived. The molecules were generated using a laser ablation source in which a vanadium rod was laser ablated and gaseous nitrous oxide (N2O) was introduced, as an oxygen donor. Subsequent supersonic adiabatic expansion cooled the molecules. The spectrum of VO was measured with quantum cascade lasers where the laser beams were perpendicularly oriented to the supersonic jet.

Pulse Ultrasound-Based Response Enhancement of a MOX Gas Sensor.

In this work, a new method to enhance the sensing response of an ultrasonically catalyzed metal oxide gas sensor has been proposed and developed, in which pulse ultrasound is employed to enhance the redox reaction at the sensing surface. It is experimentally confirmed that with a proper pulse width, the negative effect of acoustic streaming on the ultrasonic enhancement process can be effectively suppressed. Comparing the steady responses of five target gases under the pulse and continuous ultrasound, respectively, it is found that the pulse ultrasound causes a better catalysis effect, and response enhancement (RE) by the pulse ultrasound with an optimal pulse width depends on the ultrasonic strength as well as the species and concentration of the target gas. For 2 ppm methanol, the RE by the pulse ultrasound is 50%, relative to the continuous ultrasound, when the pulse width, duty ratio, and working frequency are 0.4 ms, 50%, and 110.1 kHz, respectively. The optimal pulse width decreases when the ultrasonic strength increases and is not affected by the target gas species and concentration. The lower the target gas concentration, the larger the optimal RE caused by pulse ultrasound. Moreover, for a given pulse width, the interpulse time also affects the RE.

Guideline on the Use of Intravenous Ketamine for Procedural Sedation in the Children's Emergency Department: A Quality Improvement Project.

In pediatric emergency medicine, sedation is crucial for performing some therapeutic procedures in children. Ketamine is still not widely used, despite being the preferred agent due to its effectiveness and safety profile. Implementing a guideline for intravenous ketamine in emergencies requiring procedural sedation in children, as well as training and evaluating staff competencies in performing this procedure, are the aims of this study. Senior and mid-level physicians, including pediatric nurses working in the children's emergency department (ED), have easy access to this concise repository for carrying out this procedure safely and effectively. The main objective was to implement a policy (guideline) for sedation in the children's ED. The secondary objectives were to determine whether the introduction of this policy increased the overall satisfaction rating of procedural sedation as a service offered in the Trust, to close skillgaps among staff through targeted training, and to assess the degree of recommendation for this ongoing standard of practice, in line with the current best evidence. A retrospective review of pediatric sedation cases with fractures in the children's ED of Buckinghamshire Healthcare National Health Service (NHS) Trust was conducted between June 2022 and August 2023. Surveys were sent out to assess attitudes, sedation skills, and compliance with the Royal College of Emergency Medicine (RCEM) guidelines. A policy for pediatric sedation with intravenous ketamine was later created and put into effect. Pre- and post-intervention data were compared to assess changes in sedation competency, compliance, and confidence. Out of the 103 pediatric fracture cases reviewed, 16 were identified as needing reduction upon initial evaluation, based on the child's condition at presentation. However, only one (6%) was treated with ketamine sedation in the children's ED, whereas nine cases (56%) were reduced under general anesthesia. The remainder was treated with varying use of nitrous oxide gas (Entonox) and diamorphine. Significant progress had been made after a clinical guideline for intravenous ketamine-assisted sedation in children was put into practice. Physicians reported improved knowledge of sedation techniques, knowledge of airway control, and safety in administering ketamine sedation. The percentage of respondents supporting the guidelines increased from 61% before the intervention (nValue=11) to 94% after (nValue​=17), using various metrics. These results demonstrated how well evidence-based policies and training can improve performance, competence, and safety. The use of procedural sedation in the children's EDincreased and the need for general anesthesia was significantly reduced after a uniform pediatric ketamine sedation policy was implemented. Targeted training to address skillgaps increased employee confidence and adherence to best practices.

Effect of fuel modification and after treatment techniques on emissions fuelled by diesel tyre oil blend

ABSTRACT Reusing used tires as fuel has the potential to reduce environmental harm and the quick depletion of fossil fuel resources. Fuel modifications and after-treatment techniques are the two main strategies for reducing emissions. The fuel has been blended with an antioxidant ingredient and after-treatment technology in an effort to lower the NO emission. Tire oil is produced from old tires by the pyrolysis method. Based on the test results, it looks like used tire oil could be a decent fossil fuel alternative. Fuel modification is done by adding the A-tocopherol acetate as an antioxidant additive of 300 ppm with an 80:20 diesel-to-tire oil blend powering a four-stroke, mono-barrel diesel engine. A notable reduction in NO emissions up to 15.3% was observed. A copper-based catalytic converter is used as an after-treatment technique in the exhaust of the antioxidant-doped blend, resulting in a 27.35% reduction in NO emissions. Oxidative analysis and gas chromatography-mass spectrometry were used to examine the tire oil and blend. The results showed that the pure blend had an oxidative stability of 17 hours. It was discovered by the GC-MS analysis that the blend is better suited for engine use than pure tire oil.

Silver Doped Polypyrrole Nanocomposite-based Gas sensor for Enhanced Ammonia Gas Sensing Performance at Room Temperature

Nanocomposite, which comprise organic and inorganic materials have gained increasing interest in the application for enhanced sensing response to both reducing and oxidation gases. In this study, a nanocomposite is chemical polymerization synthesized by reinforcing Ag nanoparticles with different concentration doped into the matrix of Polypyrrole (PPy). This nanocomposite is used as a sensing platform for ammonia detection with different concentration (ppm). The homogeneous distribution of Ag nanoparticles onto the PPy matrix provides a smooth and dense surface area, further accelerating the transmission of electrons. The synergistic effect of PPy@Ag matrix is responsible for the outstanding conductivity, compatibility and catalytic power of the proposed gas sensor. The structure, morphology, and surface composition of as-synthesized samples were respectively, examined via X-ray diffraction, field emission scanning electron microscopy, Ultraviolet-visible spectroscopy, Thermogravimetric analysis and Fourier transform infrared spectroscopy. The results indicated that sensor based on the PPy@Ag5 (2 gm) nanocomposite showed the highest response toward ammonia as compare to pure PPy at room temperature with a response value is 58 % to 100 ppm. Overall, the obtained findings demonstrated that the PPy@Ag nanocomposite are promising materials for gas sensing applications in environmental monitoring.

Intraocular Pressure and Safety of Vitrectomy with Vitreous Gas Replacement using Low-concentration Nitrous Oxide Gas Anesthesia.

This study aims to evaluate the efficacy and safety of vitrectomy with vitreous gas replacement using low-concentration nitrous oxide (N2O) gas anesthesia, focusing on intraocular pressure (IOP) changes, pain, anxiety, and safety outcomes. This retrospective study analyzed 133 patients undergoing fluid-air exchange without use of such as SF6 or C3F8, at Saneikai Tsukazaki Hospital, Japan, from April 2019 to March 2022. Participants were divided into two groups: those receiving low-concentration nitrous oxide gas anesthesia (N2O group) and those receiving local anesthesia with room air inhalation (Air group). IOP, pain, anxiety levels, and intraoperative complications were assessed. No significant differences were found in IOP changes postoperatively between the N2O and Air groups. The N2O group reported significantly lower pain scores and had lower intraoperative systolic blood pressure and heart rate changes compared with the Air group. No significant intraoperative or postoperative complications were observed in either group. Vitrectomy with fluid-air exchange using low-concentration nitrous oxide gas anesthesia is safe, does not increase IOP, and may offer benefits in reducing intraoperative pain and stabilizing vital signs compared with traditional local anesthesia methods. This approach could be considered a viable option for vitreous surgery requiring fluid-air exchange.

Study on Room Temperature Oxidation Characteristics of Primary Active Sites in Low-Rank Coal from Western Mining Areas After Vacuum Desorption

ABSTRACT CO exceeding safety limits during room temperature oxidation (RTO) in low-rank coal mines, particularly in western regions, has garnered significant attention. This study systematically investigates the oxidation behavior of primary active sites in low-rank coal and their role in CO generation and safety limit exceedance. A vacuum desorption apparatus combining vacuum drying with cyclic oxidation technology was used to remove moisture and gases from coal samples under low-temperature, high-vacuum conditions, while accumulating oxidation gases. The oxidation process was studied comprehensively through RTO experiments across different coal types, cyclic desorption-oxidation tests on a single coal sample, and analyses using low-temperature nitrogen adsorption, XPS, and in-situ ESR. The results showed that CO and CO₂ concentrations continuously increased during RTO for all coal types. Samples subjected to vacuum desorption exhibited significantly higher oxidation activity, revealing the involvement of previously concealed active sites. As desorption cycles increased, oxidation capacity gradually weakened, with a marked decrease in the initial oxidation rate by Cycle 4, suggesting progressive depletion of exposed active sites. Changes in pore structure and functional groups indicate that pore characteristics and C-C/C-H structures influence oxidation reactions. In-situ free radical experiments revealed that when primary active sites remained intact, desorption significantly exposed concealed free radicals, particularly alkyl radicals. However, as active sites were depleted, subsequent desorption did not significantly increase free radical exposure, limiting further oxidation. CO was less affected by coal pore adsorption compared to CO₂, making it a more reliable indicator of oxidation intensity. This study provides insights into gas evolution during RTO of primary active sites in coal and offers theoretical guidance for addressing Coal spontaneous combustion and CO exceedance in low-rank coal mines.

Oxidative Injury to Lung Mitochondrial DNA is a Key Contributor for the Development of Chemical Lung Injury.

The mechanisms and extent to which inhalation of oxidant gases damage the mitochondrial genome contributing to the development of acute and chronic lung injury have not been investigated. C57BL/6 mice exposed to chlorine (Cl 2 ) gas and returned to room air, developed progressive loss of lung DNA glycosylase OGG1, significant oxidative injury to mtDNA, decreased intact lung mitochondrial (mt) DNA, generation of inflammatory pathway by DAMPs causing airway and alveolar injury with significant mortality. Global proteomics identified over 1400 lung proteins with alteration of key mitochondrial proteins at 24 h post Cl 2 exposure. Intranasal instillation of a recombinant protein containing mitochondrial targeted OGG1 (mitoOGG1) post exposure, decreased oxidative injury to mtDNA, lung mitochondrial proteome, severity of the acute and chronic lung injury and increased survival. These data show that injury to the mt-genome is a key contributor to the development of acute and chronic lung injury.

Low-Dose Ozone as a Eustress Inducer: Experimental Evidence of the Molecular Mechanisms Accounting for Its Therapeutic Action.

Ozone (O3) is an unstable, highly oxidative gas that rapidly decomposes into oxygen. The therapeutic use of O3 dates back to the beginning of 20th century and is currently based on the application of low doses, inducing moderate oxidative stress that stimulates the antioxidant cellular defences without causing cell damage. In recent decades, experimental investigations allowed the establishment of some basic mechanisms accounting for the therapeutic effects of eustress-inducing low-dose O3. In this review, special attention was given to the impact of O3 administration on the cell oxidant-antioxidant status, O3 anti-inflammatory and analgesic properties, efficacy in improving tissue regeneration, and potential anticancer action. Low O3 concentrations proved to drive the cell antioxidant response mainly by activating nuclear factor erythroid 2-related factor 2. The anti-inflammatory effect relies on the downregulation of pro-inflammatory factors and the modulation of cytokine secretion. The painkilling action is related to anti-inflammatory processes, inhibition of apoptosis and autophagy, and modulation of pain receptors. The regenerative potential depends on antioxidant, anti-inflammatory, anti-apoptotic, and pro-proliferative capabilities, as well as fibroblast activation. Finally, the anticancer potential is based on oxidant and anti-inflammatory properties, as well as the inhibition of cell proliferation, invasion, and migration and the induction of apoptosis.

Investigation of the Effect of Ammonia As Ambient Air Contaminant on PEM Fuel Cell Stack Performance and Degradation Using EIS, Thda and Different Gas Analysis Methods

The negative effects of airborne contaminants on polymer electrolyte membrane fuel cell (PEMFC) have already been shown in several publications. [1] Among these contaminants, ammonia (NH3) with its multistep reversible and irreversible effects is particularly significant. Recent studies on air quality in urban areas have revealed a notable increase in ammonia levels within a span of two years. [2] This rapid increase can be attributed to the growing prevalence of EURO-6 diesel vehicles equipped with selective catalytic reduction (SCR) cats, which results in ammonia slip during the nitrogen oxide reduction process in diesel engines. [2]Ambient air is the most common used oxidant gas in mobile and stationary PEM fuel cell systems. The performance of fuel cell can suffer beyond the oxygen gain from airborne contaminants, which also have the potential to accelerate degradation. To prevent that airborne contaminants reach the fuel cell cathode, air filter systems consisting of particle filter and specially for fuel cell requirements developed filter are installed at the cathode inlet. Despite the installation of an air filter system, airborne contaminants can still reach the fuel cell cathode.The focus of this investigation is on the effects of ammonia in PEM fuel cell stacks. In contrast to single cell operation, stack operation can introduce additional effects such as cell-to-cell inhomogeneities and varying degrees of ammonia-induced degradation among cells. For the investigation, experiments with a PEMFC stack are going to be done on a fuel cell testbed equipped with an impedance analyzer. Ammonia is going to be mixed into the cathode air in the ppb range. Its effects on PEMFC stack performance are going to be investigated with electrochemical impedance spectroscopy (EIS) and total harmonic distortion analysis (THDA). The cathode exhaust gas is also going to be analyzed by gas analyzers such as FTIR gas analyzer and mass spectrometry.It is planned to test the PEMFC stack under different operating conditions like temperature, relative humidity and pressure of inlet gases, with various parameters and different cathode gas mix ratios while monitoring possible conversion of impurities via FTIR and the stack state of health using THDA and conventional technologies to understand the link between the effect of ammonia on fuel cell stack performance, on its lifetime and to determine possible early indicators.