Addition Of Peroxide Research Articles

용액 내 플라즈마 반응을 이용한 아세틸살리실산 분해 연구

In this work, the plasma reaction in solution was applied to decompose acetylsalicylic acid, a nonsteroidal anti-inflammatory drugs detected in water and soil environment. In particular, the effects of electrical energy supply conditions and oxidation additives as hydrogen peroxide on the decomposition reaction rate of acetylsalicylic acid were evaluated. The amount of active species such as hydroxyl radicals and oxygen radicals generated by plasma reaction was determined by the electrical operating parameters. By increasing the electrical operation parameter, the decomposition rate constants of acetylsalicylic acid were proportionally increasing. The addition of hydrogen peroxide into solution showed the positive effect in decomposing the acetylsalicylic acid because the hydrogen peroxide promoted the generation of hydroxyl radical. On the other hands, the excess of hydrogen peroxide could occur the scavenger effect that formed the recombination of hydroxyl radical so that the decomposition rate of acetylsalicylic acid was decreased.

The Efficacy of Peroxide Solutions in Decreasing Cutibacterium acnes Burden Around the Shoulder.

Cutibacterium acnes is a common pathogen associated with surgical site infection after shoulder surgery; current standard of care products are largely ineffective at reducing C acnes bacterial burden before surgery. The purpose of this systematic meta-analysis was to assess the efficacy of peroxide-containing solutions (PCS) in decreasing the C acnes burden on the shoulder. This was a systematic review of all level I and II studies investigating the effect of peroxidase-containing products for skin preparation. We extracted data regarding demographics, treatment details and timing, study methodology, and culture positivity. Forest plots were used to determine the pooled efficacy of peroxide solutions versus control. Seven studies with 412 patients were eligible for inclusion. Notable heterogeneity was observed in the manner and timing of peroxide application. Two studies applied PCS at the time of surgery; four studies applied PCS in the 24- to 72-hour period leading up to culture acquisition. Compared with the placebo, peroxide significantly diminished C acnes culture positivity (Hazard Ratio 0.174, P = 0.009). When considering using peroxide-containing products in the period leading up to surgery or at the time of surgery, in addition to standard preparation, the addition of peroxide significantly diminished C acnes culture positivity (HR 0.467, P = 0.004). Owing to study heterogeneity, we could not make notable comparisons based on the timing or duration of benzoyl peroxides application. Despite heterogeneity in study design, pooled results of high-quality data suggest that the addition of PCS can markedly reduce C acnes bioburden. This review was not able to identify the ideal regimen for the utilization of PCS for reduction of C acnes burden. Level II.

Electrophoretic fabrication of a robust chitosan/polyethylene glycol/polydopamine composite film for UV-shielding application

The film-forming process of chitosan composite films is an important issue because it affects their experimental design, chemicals used, and feasibility of large-scaled fabrication. In this work, electrophoresis is employed to produce chitosan composite films with significantly reduced processing time and environmentally friendly chemicals. With the addition of hydrogen peroxide and polyethylene glycol, the parasitic hydrogen bubble formation during the electrophoresis of chitosan and polydopamine is effectively inhibited that leads to the formation of a defectless chitosan/polyethylene glycol/polydopamine composite film which could be removed from the substrate readily. In addition, the chitosan/polyethylene glycol/polydopamine composite film reveals significantly improved tensile strength and a slower decomposition rate as compared to those of chitosan film and chitosan/polyethylene glycol composite film. This is attributed to the strong interaction between chitosan and polydopamine. Lastly, the chitosan/polyethylene glycol/polydopamine composite film exhibits excellent UV-shielding ability without compromising its visible transparency.

Enhanced Performance of Hydrogen Peroxide Modified Pozzolan-Based Geopolymer for Abatement of Methylene Blue from Aqueous Medium

Pozzolan-based eco-adsorbents were synthesized by geopolymerization with addition of hydrogen peroxide (H2O2) with mass ratios 0% (GP0) and 1% (GP1) and the products used to sorb cationic methylene blue (MB) dye from water. The chemical composition, textural properties, mineral composition, surface functional groups, as well as morphology and internal structure of these samples were determined by the X-ray fluorescence, adsorption of nitrogen by the B.E.T (Bruamer Emmet Teller) method, X-ray diffraction, Fourier Transformed Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM), respectively. The effects of contact time, dye initial concentration, adsorbent dosage, pH and temperature were examined and are herein reported. Incorporation of 1% H2O2 increased the specific surface area from 4.344 to 5.610 m2/g representing ~29% increase in surface area. This translated to an increase in the MB adsorption capacity by 15 orders of magnitude from 24.4 to 366.2 mg/g for GP0 and GP1, respectively. The adsorption rates of methylene blue onto the two geopolymers were best described by the pseudo-second order kinetic model. The adsorption equilibrium data were best described by the Sips and Freundlich isotherms models for GP0 and GP1, respectively. Thermodynamically, it was determined that the adsorption of methylene blue onto GP0 and GP1 is a physical and endothermic process. The results show that incorporation of a low amount of hydrogen peroxide into pozzolan-based geopolymers increases their adsorption capacity for methylene blue dye stupendously while preserving the surface chemistry.

In situ produced hydrogen peroxide by biosynthesized Palladium nanoparticles and natural clay mineral for Highly-efficient Carbamazepine degradation

Fenton reaction is an effective method to remove refractory organics such as carbamazepine (CBZ) from water streams. Nevertheless, its application is greatly compromised by extra hydrogen peroxide (H2O2) addition and iron mud accumulation. Herein, Fenton-like process with in situ produced H2O2 by biosynthesized palladium nanoparticles (bioPd-NPs) and natural iron-bearing clay minerals is proposed for CBZ degradation. The bioPd-NPs prepared by Shewanella loihica PV-4 were in the size range of 5–20 nm, which catalyzed the in situ production of H2O2 from formic acid (FA) and oxygen. Then the in situ generated H2O2 underwent Fenton-like reactions with nontronite for CBZ degradation. With bioPd-NPs and nontronite dosage of 1 g/L and FA concentration of 20 mM, the complete CBZ (10 mg/L) degradation was achieved within 60 min. Oxidative radicals such as HO· and H2O2 generated in our constructed system played key roles in CBZ degradation. Intermediates/products identification and theoretical calculation revealed that hydroxylation was the main CBZ degradation pathway. This work provides a promising Fenton-like technology for elimination of CBZ from environment with prevention of additional H2O2 supplementation and excessive iron mud production.

Electrolytically Ionized Abrasive-Free CMP (EAF-CMP) for Copper

Chemical–mechanical polishing (CMP) is a planarization process that utilizes chemical reactions and mechanical material removal using abrasive particles. With the increasing integration of semiconductor devices, the CMP process is gaining increasing importance in semiconductor manufacturing. Abrasive-free CMP (AF-CMP) uses chemical solutions that do not contain abrasive particles to reduce scratches and improve planarization capabilities. However, because AF-CMP does not use abrasive particles for mechanical material removal, the material removal rate (MRR) is lower than that of conventional CMP methods. In this study, we attempted to improve the material removal efficiency of AF-CMP using electrolytic ionization of a chemical solution (electrolytically ionized abrasive-free CMP; EAF-CMP). EAF-CMP had a higher MRR than AF-CMP, possibly due to the high chemical reactivity and mechanical material removal of the former. In EAF-CMP, the addition of hydrogen peroxide (H2O2) and citric acid increased the MRR, while the addition of benzotriazole (BTA) lowered this rate. The results highlight the need for studies on diverse chemical solutions and material removal mechanisms in the future.

Effect of EVA and DCP addition on injection moldability and tensile properties of recycled PE from disposable drip tapes

Abstract The effects of ethylene-vinyl acetate copolymer (EVA) and dicumyl peroxide (DCP) addition on injection moldability and tensile properties of recycled polyethylene (PE) from disposable drip tapes were studied. DCP showed an adverse impact on the injection moldability of recycled PE materials, while EVA had positive effects on it. Tensile properties of the reproduced PE increased with the increasing amount of EVA up to 10 wt.% and decreased beyond it. The DCP addition reduced the elastic properties of the reproduced PE, while it enhanced the tensile strength. Overall, the co-addition of 6 wt.% EVA + 0.4 wt.% DCP could improve the tensile strength of the reproduced PE materials.

Evaluation of the effectiveness of skin preparation methods for the reduction of Cutibacterium acnes (formerly Propionibacterium acnes) in shoulder surgery: a systematic review.

Cutibacterium acnes (C. acnes) is the most common pathogen responsible for post-operative shoulder infections. The purpose of this study was to evaluate the effectiveness of skin preparation methods against C. acnes in shoulder surgery. A systematic review was conducted evaluating the effectiveness of skin preparation methods in the reduction of C. acnes in patients undergoing shoulder surgery. Outcomes were assessed based on the effectiveness of the method used; side effects and cost were also analysed. Of the 19 included studies, 9 evaluated pre-surgical home treatments: 8 assessed benzoyl peroxide (BPO) and 6 concluded it is effective in reducing C. acnes. Nine studies assessed surgical skin preparation and concluded that Chlorhexidine gluconate (CHG) was not effective; in contrast hydrogen peroxide reduced C. acnes. Finally, one study evaluated an aseptic protocol using CHG and concluded that it was not effective. It was demonstrated that BPO as home treatment is effective in reducing C. acnes load on skin; it rarely causes side effects and is also cost-effective. This study highlights non-effectiveness of CHG. There was some evidence that the addition of hydrogen peroxide could have a positive effect in the reduction of C. acnes skin load; however, more studies are required.

Photochemical degradation of β-hexachlorocyclohexane in snow and ice.

Hexachlorocyclohexane (HCH), a typical organochloride pesticide, is one of the persistent organic pollutants. Despite the ban on technical grade HCH, it has been continuously observed at a steady level in the environment. The photochemical degradation of β-HCH in snow and ice under ultraviolet (UV) irradiation was investigated in this study. The effects of pH as well as common chemical components in snow on the degradation kinetics were investigated. In addition, the photodegradation products were determined and the reaction mechanism was hypothesized. The results showed that under UV irradiation, β-HCH can be photolyzed in snow and ice, with the photochemical degradation process conforming to the first-order kinetic equation. Changing the pH and adding Fe2+ had minimal effect on the photochemical degradation kinetics, while the presence of acetone, NO2-, NO3- and Fe3+ significantly inhibited the process. The addition of hydrogen peroxide slightly inhibited the photochemical degradation of β-HCH. Finally, the reaction rate, products and degradation mechanism of β-HCH in snow were compared with those in the ice phase. The photochemical degradation rate of β-HCH in snow was approximately 24 times faster than that in the ice phase. The photolysis product of β-HCH in snow was α-HCH, produced by the isomerization of β-HCH. However, in ice, in addition to α-HCH, pentachlorocyclohexene was produced by dechlorination. The results of this study are helpful in understanding the transformation of organochlorine pesticides in snow and ice, as well as in providing a theoretical basis for snow and ice pollution prevention and control.

Design of 3D-supramolecular metal organic framework of zinc as photocatalyst for the degradation of methylene blue through advanced oxidation process

A 3D- supramolecular zinc incorporated metal organic framework has been synthesized using 2,6-naphthalene disulphonic acid as the ligand and 4,4’-bipyridine as the co-ligand by adopting a hydrothermal strategy. The MOF was characterized for its composition, functional groups, morphology as well as crystal structure, by resorting to various analytical techniques. The visible light driven photocatalytic activity of the MOF was analyzed with respect to the degradation of methylene blue. The addition of hydrogen peroxide as the electron acceptor to an analyte system of Zn-MOF and the dye remarkably enhanced the photocatalytic activity. The degradation of the dye proceeds through ligand-to-metal charge transfer (L-MCT). The enhanced photocatalytic activity in the presence of the electron acceptor is attributed to advanced oxidation process. The trapping experiments using scavengers indicate that hydroxyl radicals and holes are the species responsible for photocatalytic degradation of MB using Zn-MOF. Leaching experiments prove the stability of the MOF. Recycling experiments proves the long term stability of the MOF photocatalyst in the degradation of methylene blue.

Effects of organic matter, ammonia, bromide, and hydrogen peroxide on bromate formation during water ozonation

Ozone is widely applied for disinfection in drinking water treatment and the disinfection by-product bromate would be produced during the ozonation of bromide-bearing water. Hydrogen peroxide (H2O2) addition could effectively control the formation of bromate. However, the bromate depression performance would be impacted by water qualities. In this study, typical source water containing bromide in eastern China was selected to investigate bromate depression effect under different organic matter, ammonia and bromide concentrations during the H2O2–O3 process. The results display that organic matter, ammonia and bromide concentration could influence the formation of bromate significantly. As tyrosine was applied to increase the dissolved organic carbon (DOC) concentration of source water by 2.0 and 3.0 mg/L, the total concentration of bromate produced decreased gradually as the H2O2/O3 (g/g) doses increased from 0 to 1.0 and bromate concentration could be controlled below 10 μg/L as H2O2/O3 (g/g) was 0.5 and 1.0. As ammonia concentration increased by 0.1 and 0.5 mg/L, lower H2O2/O3 (g/g) doses would lead to an increase in bromate generation. As more H2O2 was added in water, the bromate formation would be suppressed. The increase of bromide concentration induced higher bromate formation. When the bromide concentration increased by 50 and 200 μg/L, bromate concentration was 10.7 μg/L and 41.2 μg/L respectively at the H2O2/O3 (g/g) of 1.0, higher than the standard level. As 200 μg/L of bromide was added to the water, bromate concentration increased significantly and then decreased as H2O2/O3 (g/g) increased and more H2O2 would be needed for bromate control.

Reusable System for Phenol Detection in an Aqueous Medium Based on Nanodiamonds and Extracellular Oxidase from Basidiomycete Neonothopanus nambi.

A reusable system for phenol determination in an aqueous medium was obtained by adsorption of extracellular oxidase from fungus Neonothopanus nambi onto modified nanodiamonds (MND) synthesized by detonation. It was found that the enzyme strongly binds to MND and exhibits catalytic activity in the reaction of co-oxidation of phenol with 4-aminoantipyrine without the addition of hydrogen peroxide. In the presence of the MND-oxidase complex, a significantly (by an order of magnitude) higher yield of the reaction product is recorded as compared to the yield in the presence of a free enzyme; the mechanism of the revealed effect is discussed. Model experiments have demonstrated the multiple use of the MND-oxidase complex for testing phenol in aqueous samples. The immobilized enzyme exhibits functional activity during long-term (2 months) storage of the MND-oxidase complex at 4°C. The data obtained create the prerequisites for using the created system in environmental monitoring of water pollution with phenol.

Structural and morphological optimization of Ni doped ZnO decorated silicon nanowires for photocatalytic degradation of methylene blue

In the current work, nickel doped zinc oxide decorated silicon nanowires (SiNWs) were elaborated and applied for photocatalytic degradation of organic dyes. Nickel doped zinc oxide (Ni-ZnO) was synthesized via a facile sol-gel process of metal acetates by varying Ni content from 0 to 5% followed by the annealing process. As-prepared Ni-ZnO was subsequently spin-coated on to silicon nanowires to get ZnO-Ni/SiNWs nanohybrids. The effect of Ni doping on structural, morphological and photocatalytic properties of ZnO-Ni/SiNWs was investigated. Fourier Transform InfraRed spectroscopy (FTIR) analysis confirms the complete removal of organic moieties from as-prepared Ni-ZnO after annealing at 300˚ C. X-ray diffraction studies proved the presence of pure phase hexagonal wurtzite structure while showing a decrease of crystalline size with the increase in Ni dopant. Further, SEM and Raman mapping confirm homogeneous distribution of Ni-ZnO on Si nanowires. Photocatalysis studies showed that Ni doping enhances slightly the photocatalytic degradation of methylene blue. Highest degradation efficiency of 97% with best kinetic rate constant value was obtained for Ni-ZnO (5%)/SiNWs with hydrogen peroxide addition. The developed structure stands as promising candidates as efficient, cost-effective and reusable photocatalytic systems for organic dye decomposition.

Application Enzymatic Method for Analysis Vaginal Tabletas “Fluomizin”

Introduction: Development of a new enzymatic kinetic-photometric method for analysis of Dequalinium chloride, based on the use of enzymatic hydrolysis of acetylcholine, for determine the amount of Dequalinium chloride in the vaginal tablets “Fluomizin” No 6.
 Method: The amount of Dequalinium chloride (DCh) was determined by the degree of inhibition of the enzymatic reaction, which was evaluated by the residual unreacted substrate - acetylcholine. Determination of the residual amount of acetylcholine in the reaction mixture was performed by a kinetic-photometric method using an indicator oxidation reaction of p-phenetidine with peracetic acid, which is formed during the auxiliary reaction of perhydrolysis with addition of excess hydrogen peroxide in the reaction mixture over a period of time.
 Results: Optimal conditions were determined: pH 8.35 was selected, influence of nature of buffer solution, concentration of acetylcholine (0.05 mg / ml), cholinesterase (0.4 mg / ml), hydrogen peroxide (10,0%) and p-phenethedine (1 %), the incubation time (10 min).
 Conclusions: The procedure for determination of Dequalinium chloride content in the vaginal tablets “Fluomizin” No 6 was developed. The kinetic parameters Km (Michaelis–Menten constant) and Vmax (maximal velocity) were determined.

Degradation of antibiotic Cephalosporin C in different water matrices by ionizing radiation: Degradation kinetics, pathways, and toxicity

Cephalosporin antibiotics are ubiquitous emerging pollutants in various aquatic environments due to their extensive production and application. Herein, the radiolytic degradation of antibiotic Cephalosporin C (CEP-C) in different water matrices was comprehensively investigated using gamma radiation at various experimental conditions. The results revealed that CEP-C oxidation obeyed pseudo first-order kinetics, and 100%, 94.9%, 67.0%, 44.6% and 34.5% removal of CEP-C with 10–200 mg/L was achieved at 0.4 kGy, respectively. The degradation was faster at higher absorbed dose and acidic conditions (pH = 3.5). The inorganic anions, including SO42−, NO3−, and HCO3−, had negative influence on the degradation of CEP-C, the corresponding rate constant decreased from 4.603 to 3.667, 1.677 and 2.509 kGy−1 respectively in the presence of SO42−, NO3−, and HCO3−. The analysis of intermediate products indicated that CEP-C was oxidized to generate about 10 intermediate products. Besides, it was inferred that the thioether sulfur oxidation, β-lactam ring opening, acetyl dissociation from dihydrothiazine ring and D-α-aminohexylamide group abscission were the major reaction mechanisms of CEP-C degradation by gamma radiation. Importantly, the antibacterial activity of CEP-C could be completely vanished by gamma radiation alone, while more toxic intermediate products might be formed. Addition of hydrogen peroxide and peroxymonosulfate could significantly improve the CEP-C degradation, and reduce the toxicity of intermediates of CEP-C degradation. Similar degradation behavior was observed in the groundwater and wastewater, implying that ionizing radiation can be used for degradation of Cephalosporin in water and wastewater.

Computational analysis of the effect of hydrogen peroxide addition on premixed laminar hydrogen/air flames

In the current work, the effect of H2O2 addition on the flame structure, laminar flame speed and NOx emissions is investigated in the context of 1D laminar premixed H2/air flames at Tu = 300 and 600 K, p = 1 and 30 atm, ϕ = 0.5. Mathematical tools from the computational singular perturbation approach are used in order to identify the key chemical and transport mechanisms. The H2O2 addition causes a significant increase to the laminar flame speed (sL), heat release (Q) and NOx emissions. Indicatively, 10% H2O2 addition (per fuel volume) at Tu = 300 K, p = 1 atm results in 72% increase of sL, 100% increase of Q, and 140% increase of the mass fraction of NO. Depending the conditions the flame structure is altered through the chain carrying reaction 10f (H2O2 + H → H2O + OH) or the chain branching 9f (H2O2 (+M) → 2OH (+M)); the first is favored at low temperatures/pressures while the latter is favored at sufficiently high temperatures/pressures. Both reactions boost the radical pool generation, therefore contributing to the broadening of the reaction zone. The reaction with the largest contribution to Q that is mostly affected (decreased) by the addition of H2O2 is reaction 21 (H + O2 (+M) ↔ HO2 (+M)). Moreover, the H2O2 addition enhances the stability of the flame. Finally, the increased production of NO is mainly associated with the increased temperature that is reached with the addition of H2O2.

Improved Performance of Environmentally Friendly Blends of Biobased Polyethylene and Kraft Lignin Compatibilized by Reactive Extrusion with Dicumyl Peroxide

AbstractIn this work, different contents (0.25, 0.50, 0.75, and 1 phr) of dicumyl peroxide (DCP) are incorporated into the bio‐based high‐density polyethylene (bioPE)/kraft lignin (KL) blends with a composition of 80 and 20 wt%, respectively with the aim of improving overall performance. The samples are obtained by reactive extrusion and injection‐molding process, and then their overall performance is assessed by tensile tests, thermal analysis, optical and surface appearance, and wettability studies. The obtained mechanical properties confirm the successful interaction between bioPE and KL due to the addition of organic peroxide, which plays a key role in compatibilization. In particular, bioPE/KL blends with 1 phr of DCP achieve an increase in elongation at break of about 300% together with a noticeable increase in the impact strength of about 29% higher than the uncompatibilized bioPE/KL blend, while the tensile modulus decreases 42%. In addition, images obtained by field emission scanning electron microscopy show that the presence of DCP in the blends enhances better dispersion of KL into the bioPE matrix. The wettability analysis indicates that KL and DCP affect the hydrophobicity of the neat bioPE. Therefore, the resultant blends can be considered as potential sustainable polymers with balanced properties.

Metoprolol and Its Degradation and Transformation Products Using AOPs-Assessment of Aquatic Ecotoxicity Using QSAR.

Pharmaceuticals are found in waterbodies worldwide. Conventional sewage treatment plants are often not able to eliminate these micropollutants. Hence, Advanced Oxidation Processes (AOPs) have been heavily investigated. Here, metoprolol is exposed to UV irradiation, hydrogen peroxide, and ozonation. Degradation was analyzed using chemical kinetics both for initial and secondary products. Photo-induced irradiation enhanced by hydrogen peroxide addition accelerated degradation more than ozonation, leading to complete elimination. Degradation and transformation products were identified by high-performance liquid-chromatography coupled to high-resolution higher-order mass spectrometry. The proposed structures allowed to apply Quantitative Structure-Activity Relationship (QSAR) analysis to predict ecotoxicity. Degradation products were generally associated with a lower ecotoxicological hazard to the aquatic environment according to OECD QSAR toolbox and VEGA. Comparison of potential structural isomers suggested forecasts may become more reliable with larger databases in the future.

Intensification of advanced oxidation processes (AOPs) for the degradation of bisphenol-A

Abstract Bisphenol-A (BPA), a precursor for many polymers, is a harmful compound for living organisms if present beyond permissible limits in aqueous streams. The combinations of oxidation processes like Hydrodynamic Cavitation (HC), hydrogen peroxide (H2O2), and Fenton’s reagent (H2O2 + FeSO4) were examined for the degradation of BPA in the present study. The effects of operating parameters like inlet pressure, initial concentration of BPA, orifice geometry were investigated on BPA degradation. The degradation rates of BPA increased with inlet pressure up to 0.5 MPa and then showed a decreasing trend beyond 0.5 MPa. The initial concentration of BPA had an inverse relation with the degradation percentage. The multiple hole orifice plate showed better degradation of BPA compared to the single hole orifice plate. In the intensification studies, the addition of hydrogen peroxide to BPA in the cavitation reactor favored BPA degradation. A combination of HC + Fenton’s reagent (0.1 M H2O2 + 0.01 M FeSO4) significantly degraded BPA present in the aqueous streams.

Scavenging of reactive oxygen species mimics the anoxic response in goldfish pyramidal neurons.

Goldfish are one of a few species able to avoid cellular damage during month-long periods in severely hypoxic environments. By suppressing action potentials in excitatory glutamatergic neurons, the goldfish brain decreases its overall energy expenditure. Coincident with reductions in O2 availability is a natural decrease in cellular reactive oxygen species (ROS) generation, which has been proposed to function as part of a low-oxygen signal transduction pathway. Using live-tissue fluorescence microscopy, we found that ROS production decreased by 10% with the onset of anoxia in goldfish telencephalic brain slices. Employing whole-cell patch-clamp recording, we found that, similar to severe hypoxia, the ROS scavengers N-acetyl cysteine (NAC) and MitoTEMPO, added during normoxic periods, depolarized membrane potential (severe hypoxia -73.6 to -61.4 mV, NAC -76.6 to -66.2 mV and MitoTEMPO -71.5 mV to -62.5 mV) and increased whole-cell conductance (severe hypoxia 5.7nS to 8.0 nS, NAC 6.0 nS to 7.5 nS and MitoTEMPO 6.0 nS to 7.6 nS). Also, in a subset of active pyramidal neurons, these treatments reduced action potential firing frequency (severe hypoxia 0.18 Hz to 0.03 Hz, NAC 0.27 Hz to 0.06 Hz and MitoTEMPO 0.35 Hz to 0.08 Hz). Neither severe hypoxia nor ROS scavenging impacted action potential threshold. The addition of exogenous hydrogen peroxide could reverse the effects of the antioxidants. Taken together, this supports a role for a reduction in [ROS] as a low-oxygen signal in goldfish brain.