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The combination of ozone and hydrogen peroxide (O3/H2O2), or the peroxone process, has often been used as an advanced oxidation process (AOP) in groundwater remediation and drinking water applications. This historical precedent sometimes leads to the misconception that H2O2 addition is required to achieve AOP conditions during ozonation. This is not the case for secondary or tertiary wastewater effluent applications, in which ozone reacts with abundant dissolved organic carbon (DOC) to generate hydroxyl radicals (∙OH). This study demonstrates the use of ozone with and without H2O2 addition to yield ∙OH exposures (up to 10−9 M-s) capable of achieving > 0.5-log10 attenuation of the industrial contaminant and probable human carcinogen 1,4-dioxane. This low molecular weight compound is commonly used as a surrogate when establishing AOP design criteria for potable reuse applications. DOC-normalized ozone doses (i.e., O3/DOC ratios) of ~ 1.0 and ~ 1.3 achieved 0.5-log10 attenuation of 1,4-dioxane with O3/H2O2 and O3, respectively. Also, a predictive model based on ∙OH exposure was accurate within approximately ± 10%. These results suggest that ozonation's role as an AOP, even in the absence of H2O2, should be acknowledged in regulatory frameworks to reduce unnecessary treatment redundancy and facilitate broader implementation of potable reuse. [ABSTRACT FROM AUTHOR]

The electronically nonadiabatic reaction of preassociation H + O + N2 ↔ OH* + N2 is the main channel of formation of electronically excited chemiluminescent OH* molecules during the oxidation of hydrogen in mixtures with a high content of nitrogen, e.g., during the combustion of hydrogen in air. For this reaction, within the framework of the combined theoretical and experimental approach with the use of the earlier results of quantum-chemical calculations for the rate constant of the elementary process H + O → OH* in the limit of high pressures and experimental data on OH* glow in N2-diluted H2/O2 mixtures (including those obtained in this work), a physically substantiated dependence of the rate constant on temperature and pressure has been obtained for a broad range of thermodynamic parameters (T = 200–4000 K and p = 10–3–102 atm). It has been shown that the found rate constant is in reasonable agreement with the existing results of measurements in both shock tubes and flames, with the rate constant in the process under study in a nitrogen buff er gas (M = N2) turning out to be nearly 1.3–1.8 times lower (at atmospheric pressure) than for M = Ar. It has been noted that in interpreting measurements of the temporal intensity profiles of OH* emission collected from the entire combustible volume (from the end of a shock tube), taking account of the self-absorption of emission on combustion products is substantial. [ABSTRACT FROM AUTHOR]

Non-thermal plasma (NTP) is gaining increasing attention as a promising approach for advanced water treatment to degrade persistent organic pollutants. Aqueous solutions of sulfamethoxazole (4-amino-N-(5-methylisoxazol-3-yl)-benzensulfonamide, SMZ), an antibiotic largely employed for humans and animals and a widespread persistent pollutant of waters and wastewaters, were subjected to air NTP treatment in a dielectric barrier discharge (DBD) reactor. The effects of SMZ initial concentration and of the solution pH on SMZ decomposition kinetics and transformation products were investigated. Efficient degradation was achieved, resulting in the complete removal of SMZ (10 µM initial concentration) in less than 25 min treatments, in the exhaustive mineralization (a result never reported before in plasma treatments and seldom reached also with other advanced oxidation processes) of all organic carbon in 6 h and in an energy efficiency of 6.4 g/kWh at 50% conversion. By means of HPLC-UV/Vis and LC-ESI-MSn analyses, a number of organic transformation products was identified along the path to SMZ mineralization, all present always in very small amounts and in turn decomposed at short treatment times. The effect of the solution pH on the genesis and decay of transformation products was also investigated. Based on comparisons with literature data and on previous findings obtained with the DBD reactor used in this work, it is concluded that the major reactive species involved in the degradation of SMZ are the hydroxyl radical and ozone. Finally, toxicological analyses of water initially containing 0.5 mMSMZ and subjected to 4 h NTP treatment showed that the by-products are not toxic to Raphidocelis subcapitata and Daphnia magna, while residual toxicity was detected by Aliivibrio fischeri. [ABSTRACT FROM AUTHOR]

To solve the problem of unclear targeted inhibition of key free radicals by antioxidants, this paper took the hydroxyl radical with the highest oxidation activity of coal as the inhibition target and selected five antioxidants such as ethylene diamine tetraacetic acid, tea polyphenol, citric acid, vitamin C, and proanthocyanidins. Based on the theory of quantum chemistry, the characteristics and oxidation pathway of antioxidants inhibiting coal oxidation of hydroxyl radical were analyzed. Analyze the influence characteristics of antioxidants on the evolution of free radicals in coal through an electron paramagnetic resonance experiment (ESR). The results showed that the electron density of antioxidants was mainly distributed in the functional groups of carboxyl and hydroxyl, which played a key inhibitory role, and the vicinity of carboxyl and hydroxyl and other functional groups was positive potential, which was the active site of inhibiting hydroxyl radical. The order of inhibitory capacity of the five antioxidants was determined as GTP > PC > EDTA > CA > VC. It is concluded that the energy barrier of hydroxyl radical inhibition by citric acid is much lower than that of EDTA. For the hydrogen extraction reaction, VC inhibited the hydroxyl radical pathway with a higher energy barrier than the other three antioxidants. The mechanism of five antioxidants inhibiting •OH reaction was comprehensively analyzed. It was found that tea polyphenols have more active sites that can react with •OH to quench it, so the inhibition of tea polyphenols should be the most significant. When antioxidants inhibit coal spontaneous combustion, the type, complexity, concentration, and linewidth of free radicals in coal molecules are lower than those in raw coal, with GTP antioxidants having the best inhibitory effect. The research results have important theoretical and practical significance for revealing the mechanism of coal spontaneous combustion inhibition and developing directional coal spontaneous combustion inhibition technology. [ABSTRACT FROM AUTHOR]

Electrochemical advanced oxidation processes (EAOPs) offer several advantages over conventional Advanced Oxidation Processes (AOPs) such as UV/H 2 O 2 and H 2 O 2 /O 3. This includes the absence of chemical additives and ease of control. However, high energy consumption hampers the industrial application of EAOPs. Currently, the hydrogen generated at the cathode is vented and wasted, because of its low gas purity and difficulty in collecting it. But it also underscores an opportunity where the reactor design can be improved to facilitate the collection of high-purity hydrogen for energy savings. In our study, The EAOPs reactor was designed with a proton exchange membrane (PEM) for hydrogen generation. The hydrogen at the cathode chamber is then supplied to a fuel cell to generate electricity. The energy efficiency of the EAOPs-fuel cell system is evaluated through the wastewater treatment performance and energy saving that fuel cells achieve. To optimize the EAOPs-fuel cell system, various operational conditions, including different anode types, salt concentrations, and target organic compounds, were examined to optimize the system. Our experimental results indicate that the EAOPs-fuel cell system exhibits energy-efficient performance across various operational conditions. Notably, the highest energy efficiency and recovery ratio were achieved when operating at 3 V with boron-doped diamond (BDD) as the anode. Furthermore, we investigated the impact of mass transfer on the system's energy efficiency, considering both the initial organic concentration and flow velocity. This study provided valuable insights into combining the effect of EAOPs and hydrogen fuel cells, contributing to the understanding and optimizing the oxidation performance. It also contributes to developing sustainable and cost-effective advanced oxidation technologies with wide-ranging water treatment applications. • Collecting high-purity hydrogen during wastewater treatment. • Energy recovery is achieved with hydrogen fuel cells in the design of EAOPs system. • Comparison of four common anodes' oxidation performance for energy recovery purposes. • Analysis of the relationship between the current efficiency and energy efficiency. • Gave a direction for the future development of the EAOPs system. [ABSTRACT FROM AUTHOR]

Mutations in the Microrchidia CW-type zinc finger 2 (MORC2) GHKL ATPase module cause a broad range of neuropathies, such as Charcot-Marie-Tooth disease type 2Z; however, the aetiology and therapeutic strategy are not fully understood. Previously, we reported that the Morc2a p.S87L mouse model exhibited neuropathy and muscular dysfunction through DNA damage accumulation. In the present study, we analysed the gene expression of Morc2a p.S87L mice and designated the primary causing factor. We investigated the pathological pathway using Morc2a p.S87L mouse embryonic fibroblasts and human fibroblasts harbouring MORC2 p.R252W. We subsequently assessed the therapeutic effect of gene therapy administered to Morc2a p.S87L mice. This study revealed that Morc2a p.S87L causes a protein synthesis defect, resulting in the loss of function of Morc2a and high cellular apoptosis induced by high hydroxyl radical levels. We considered the Morc2a GHKL ATPase domain as a therapeutic target because it simultaneously complements hydroxyl radical scavenging and ATPase activity. We used the adeno-associated virus (AAV)-PHP.eB serotype, which has a high CNS transduction efficiency, to express Morc2a or Morc2a GHKL ATPase domain protein in vivo. Notably, AAV gene therapy ameliorated neuropathy and muscular dysfunction with a single treatment. Loss-of-function characteristics due to protein synthesis defects in Morc2a p.S87L were also noted in human MORC2 p.S87L or p.R252W variants, indicating the correlation between mouse and human pathogenesis. In summary, CMT2Z is known as an incurable genetic disorder, but the present study demonstrated its mechanisms and treatments based on established animal models. This study demonstrates that the Morc2a p.S87L variant causes hydroxyl radical-mediated neuropathy, which can be rescued through AAV-based gene therapy. [ABSTRACT FROM AUTHOR]

The hydroxyl radical is the most aggressive and dangerous product of incomplete oxygen reduction in a body, making its determination and the effect of various antioxidants on the inhibition of OH radicals a pertinent task. We propose an impedance sensor for the determination of hydroxyl radicals, based on a graphite electrode modified with electrochemically deposited gold and a self-assembled monolayer of N-acetyl-L-cysteine (NAC). The use of NAC ensures the high selectivity of the sensor, and employing non-Faradaic impedance as a method of recording the analytical signal ensures the limit of detection for OH radicals at the level 0.01 nM with a linearity range of detectable concentrations from 0.08 to 8 nM. The developed sensor has been successfully used to assess the activity of certain antioxidants (ascorbic acid, glutathione, coenzyme Q10) towards OH radicals. [ABSTRACT FROM AUTHOR]

Context: An ab initio investigation into the potential energy landscape of the meta-aminotoluene + •OH reaction has been conducted in this study. The calculated results reveal that the reaction channel leading to the product (NHC6H4CH3 + H2O) prevails under the 300–1700 K temperature range, while the reaction path forming the product (NH2C6H4CH2 + H2O) dominates in the higher-temperature region (T ≥ 1800 K). Within the specified temperature range, the product branching ratio for the former declines from 48 to 30%, while the latter shows an increase, reaching 29%. The overall second-order rate constants of the titled reaction obtained at the pressure 760 Torr (N2) can be illustrated by the modified Arrhenius expression of ktotal = 1.46 × 10–13 T0.58 exp[(-0.759 kcal.mol−1)/RT] cm3 molecule−1 s−1 and ktotal = 1.86 × 10–22 T3.24 exp[(-5.086 kcal.mol−1)/RT] cm3 molecule−1 s−1, covering the temperature range of T = 300–600 K and T > 600 K, respectively. The total rate constant at the ambient conditions in this work, 1.43 × 10–11 cm3 molecule−1 s−1, has been found to be roughly one order of magnitude lower than the available experimental data, ~ 1.2 × 10–10 cm3 molecule−1 s−1, measured by Atkinson et al., Rinke et al., and Witte et al., or the theoretical value, 4.4 × 10–10 cm3 molecule−1 s−1, and calculated by Abdel-Rahman and co-workers for the aniline + •OH reaction. Methods: The structures of reactants, transition states, intermediate states, and products of the meta-aminotoluene + •OH reaction are calculated with the aug-cc-pVTZ basis set and the methods DFT/B3LYP and CCSD(T). The rate constants and branching ratios in the 300–2000 K temperature range are calculated with the statistical theoretical TST and RRKM master equation computations including tunneling corrections, with potential energy surface constructed by the CCSD(T)//B3LYP/aug-cc-pVTZ approach. Table of Content Graphic [ABSTRACT FROM AUTHOR]

Anodic oxidation is a promising method for removing organic pollutants from water due to its high nonselectivity and effectiveness. Nevertheless, its widespread application is limited due to its low current efficiency, high energy consumption and low treatment rates. These problems may be overcome by the optimization of the process parameters, reactor design and electrode geometry, by coupling the experimental investigations with mathematical modeling. Here we review the modeling of anodic oxidation with focus on basics of this process, the competition phenomenon in real wastewater, flow cells and batch cells, historical aspects, general modeling equations, modeling with plate electrodes, modeling with porous 3-dimension electrodes and the density functional theory. Mathematical modeling can provide current, voltage and concentration distributions in the system. Mathematical modeling can also determine the effects on the performance of parameters such as diffusion layer thickness, flow velocity, applied current density, solution treatment time, initial concentration and diffusion coefficients of organic pollutants, electrode surface area, and oxidation reaction rate constant. Mathematical models allow to determine whether the limiting factor of the process is kinetics or diffusion, and to study the impact of competition of phenomena. The density functional theory provides information on probable reaction pathways and by-products. [ABSTRACT FROM AUTHOR]

We revisit one of the most used techniques for quantifying the aqueous OH radicals (OHaq) in plasma–liquid systems, the molecular probe method which obtains the [OHaq] by measuring a stable material formed through a rapid reaction between the molecular probe and the OHaq. In this study, we used disodium terephthalate (NaTA) as the molecular probe; the experimental results with a theoretical analysis suggest that to obtain the correct OHaq concentration, the concentration of the molecular probe should be greater than a certain value, which depends on the types of the plasma–liquid systems. However, this is not the case in most of the existing reports in which the NaTA is often much less than the requisite value. [ABSTRACT FROM AUTHOR]

The objective of this study was to synthesize a novel antibacterial and anticancer nanoformulation using aloe vera-derived carbon quantum dots (Cdot) and chromium-doped alumina nanoparticles (Al2O3:Cr/Cdot NPs) via a sol–gel method. X-ray diffraction (XRD) analysis confirmed crystalline NPs with a size range of 10–12 nm, while energy-dispersive X-ray spectroscopy (EDS) revealed their elemental composition without impurities. Fourier-transform infrared spectroscopy (FT-IR) indicated strong interactions between Cdot and Al2O3:Cr NPs, forming a robust heterostructure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images provided visual confirmation of monodisperse, spherical NPs, ensuring uniformity for further applications. Evaluation of reactive oxygen species (ROS) demonstrated superior generation of singlet oxygen and hydroxyl radicals by Al2O3:Cr/Cdot NPs, essential for photodynamic therapy. Minimum inhibitory concentration (MIC) tests revealed potent antibacterial activity against drug-resistant bacteria, inhibiting biofilm formation by 89% and 95% for MRSA and P. aeruginosa PAO1, respectively. Furthermore, the anticancer activity of Al2O3:Cr/Cdot NPs was assessed using C26 cells, demonstrating enhanced cytotoxicity upon UVA exposure. The NPs exhibited an inhibitory concentration (IC50) of 20 μg/mL without UVA exposure, decreasing to 10 μg/mL with UVA exposure, highlighting the synergistic effect of UVA light in enhancing cytotoxicity. Overall, these findings underscore the significant potential of Al2O3:Cr/Cdot NPs as multifunctional agents for addressing drug-resistant bacteria and advancing cancer therapy, offering promising avenues for nanomedicine research and development. [ABSTRACT FROM AUTHOR]

Ionizing radiation induces many different types of DNA lesions. But one of its characteristics is to produce complex DNA damage, of which tandem DNA damage has received much attention, owing to its promise of distinctive biological properties. Oxidative stresses in response to inflammation in tissues and metal-catalyzed reactions that result in generation of radicals also form these DNA lesions. In this minireview, we have summarized the formation of the tandem lesions as well as the replication and repair studies carried out on them after site-specific synthesis. Many of these lesions are resistant to the traditional base excision repair, so that they can only be repaired by the nucleotide excision repair pathway. They also block DNA replication and, when lesion bypass occurs, it may be significantly error-prone. Some of these tandem DNA lesions may contribute to ageing, neurological diseases, and cancer. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) are increasingly recognized as theranostic agents in radiation oncology. Hence, the interaction of these nanoparticles with biomolecules viz DNA, RNA, and proteins needs to be investigated. In this study, the potential radioprotective role of AuNPs in preventing free radicalinduced changes in bovine serum albumin (BSA) was investigated using ultraviolet-visible (UV-Vis) spectroscopy, fluorescence, Fourier-transform infrared (FTIR) spectroscopy, circular dichroism (CD), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and 5,5'-Dithiobis-(2-nitrobenzoic acid) (DTNB) assay. γ-irradiation of the protein disrupts the ordered structure of the protein. AuNPs reduced the •OH-induced oxidation of tryptophan (Trp) to nearly half of that without the AuNPs. CD studies revealed that the % α helix of BSA post-irradiation in the presence of AuNPs was higher (62%) than that without AuNPs (53%). DTNB assay results showed that, following irradiation of BSA, 25% of the thiol content was retained in the presence of AuNPs, indicating that the thiol group was substantially protected with a retained thiol content of ~ 70%. This suggested that AuNPs protected the protein from degradation by scavenging the free radicals generated during radiation-induced oxidation. [ABSTRACT FROM AUTHOR]

A simple sol-gel method has been utilized to synthesize MAl2O4:Cr catalysts (M = Mg, Co, Zn). The spinel-type MAl1.9Cr0.1O4 was formed after Cr ions were introduced into MAl2O4, as confirmed by various characterization methods. The particle size of MAl2O4:Cr catalyst increases with the increasing of the M ion radius, and CoAl2O4:Cr catalyst has the highest uniformity with an average particle size of 60 nm. The CoAl2O4:Cr catalyst is effective in degrading oil and gas field wastewater through the combination of ultrasonic and simulated solar irradiation and has a high visible light absorption coefficient. The CoAl2O4:Cr catalyst has high cyclic stability, and its optimal catalyst content is 0.5 g/L. Capture experiment and possible mechanism analysis confirm that the electrons, holes, hydroxyl radicals and superoxide radicals are the main active species in CoAl2O4:Cr catalyst for the degradation of oil and gas field wastewater. [ABSTRACT FROM AUTHOR]

In this study, the mechanism of the reaction between 4-methyl aniline and hydroxyl free radicals was computed using the M06-2X and CCSD(T) methods, along with the 6-311++G(3df,2p) basis set. The kinetics of the reaction were calculated utilizing the transition state theory and the microcanonical Rice–Ramsperger–Kassel–Marcus theory. The calculated results revealed that NH-C6H4-CH3 was the key product of the system. The total rate coefficient of the system, k_total = 2.04 × 10−18 T2.07 exp[(11.2 kJ/mol)/RT] cm3/s, was found under the 300–2000 K interval, with P = 760 Torr. At the ambient conditions, the velocity of this reaction was about ten times larger than that of the reaction between C6H5CH3 and hydroxyl free radicals, but it was smaller than the aniline + OH rate. [ABSTRACT FROM AUTHOR]

Air cleaning technologies are needed to reduce indoor concentrations and exposure to volatile organic compounds (VOCs). Currently, air cleaning technologies lack an accepted test standard to evaluate their VOC removal performance. A protocol to evaluate the VOC removal performance of air cleaning devices was developed and piloted with two devices. This method injects a VOC mixture and carbon dioxide into a test chamber, supplies outdoor air at a standard building ventilation rate, periodically measures the VOC concentrations in the chamber using solid phase microextraction-gas chromatography-mass spectrometry over a 3-h decay period, and compares the decay rate of VOCs to carbon dioxide to measure the VOC removal air cleaning performance. The method was demonstrated with both a hydroxyl radical generator and an activated carbon air cleaner. It was shown that the activated carbon air cleaner device tested had a clean air delivery rate an order of magnitude greater than the hydroxyl radical generator device (72.10 vs 6.32 m3/h).

The hydroxyl radical (OH) is the dominant oxidant in the outdoor environment, controlling the lifetimes of volatile organic compounds (VOCs) and contributing to the growth of secondary organic aerosols. Despite its importance outdoors, there have been relatively few measurements of the OH radical in indoor environments. During the House Observations of Microbial and Environmental Chemistry (HOMEChem) campaign, elevated concentrations of OH were observed near a window during cooking events, in addition to elevated mixing ratios of nitrous acid (HONO), VOCs, and nitrogen oxides (NOX). Particularly high concentrations were measured during the preparation of a traditional American Thanksgiving dinner, which required the use of a gas stove and oven almost continually for 6 h. A zero-dimensional chemical model underpredicted the measured OH concentrations even during periods when direct sunlight illuminated the area near the window, which increases the rate of OH production by photolysis of HONO. Interferences with measurements of nitrogen dioxide (NO2) and ozone (O3) suggest that unmeasured photolytic VOCs were emitted during cooking events. The addition of a VOC that photolyzes to produce peroxy radicals (RO2), similar to pyruvic acid, into the model results in better agreement with the OH measurements. These results highlight our incomplete understanding of the nature of oxidation in indoor environments.

Oxidative potential (OP) has been proposed as a possible integrated metric for particles smaller than 2.5 μm in diameter (PM2.5) to evaluate adverse health outcomes associated with particulate air pollution exposure. Here, we investigate how OP depends on sources and chemical composition and how OP varies by land use type and neighborhood socioeconomic position in the Los Angeles area. We measured OH formation (OPOH), dithiothreitol loss (OPDTT), black carbon, and 52 metals and elements for 54 total PM2.5 samples collected in September 2019 and February 2020. The Positive Matrix Factorization source apportionment model identified four sources contributing to volume-normalized OPOH: vehicular exhaust, brake and tire wear, soil and road dust, and mixed secondary and marine. Exhaust emissions contributed 42% of OPOH, followed by 21% from brake and tire wear. Similar results were observed for the OPDTT source apportionment. Furthermore, by linking measured PM2.5 and OP with census tract level socioeconomic and health outcome data provided by CalEnviroScreen, we found that the most disadvantaged neighborhoods were exposed to both the most toxic particles and the highest particle concentrations. OPOH exhibited the largest inverse social gradients, followed by OPDTT and PM2.5 mass. Finally, OPOH was the metric most strongly correlated with adverse health outcome indicators.

Ionizing radiation induces many different types of DNA lesions. But one of its characteristics is to produce complex DNA damage, of which tandem DNA damage has received much attention, owing to its promise of distinctive biological properties. Oxidative stresses in response to inflammation in tissues and metal-catalyzed reactions that result in generation of radicals also form these DNA lesions. In this minireview, we have summarized the formation of the tandem lesions as well as the replication and repair studies carried out on them after site-specific synthesis. Many of these lesions are resistant to the traditional base excision repair, so that they can only be repaired by the nucleotide excision repair pathway. They also block DNA replication and, when lesion bypass occurs, it may be significantly error-prone. Some of these tandem DNA lesions may contribute to ageing, neurological diseases, and cancer.

In this study, the mechanism of the reaction between 4-methyl aniline and hydroxyl free radicals was computed using the M06-2X and CCSD(T) methods, along with the 6-311++G(3df,2p) basis set. The kinetics of the reaction were calculated utilizing the transition state theory and the microcanonical Rice–Ramsperger–Kassel–Marcus theory. The calculated results revealed that NH-C6H4-CH3 was the key product of the system. The total rate coefficient of the system, k_total = 2.04 × 10−18 T2.07 exp[(11.2 kJ/mol)/RT] cm3/s, was found under the 300–2000 K interval, with P = 760 Torr. At the ambient conditions, the velocity of this reaction was about ten times larger than that of the reaction between C6H5CH3 and hydroxyl free radicals, but it was smaller than the aniline + OH rate.

To investigate the electrocatalytic degradation effect of anthracene in coking wastewater, Ti/PbO2, Ti/PANI/PbO2 and Ti/PANI/PbO2-Ce electrodes were prepared by electrodeposition, and the electrodes were subjected to scanning electron microscopy and X-ray diffraction characterization, electrochemical performance test, hydroxyl radical (·OH) production capacity test and accelerated lifetime test.The results showed that the Ti/PANI/PbO2-Ce electrode modified with polyaniline (PANI) and cerium (Ce) had better surface morphology and higher catalytic activity, and could produce more ·OH with an oxygen precipitation potential of 1.83 V and an accelerated lifetime of 720 min.The Ti/PANI/PbO2-Ce electrode was used for the degradation of anthracene in coking wastewater, and the effects of the main factors on the degradation effect were investigated, and the optimal degradation conditions for anthracene were obtained as voltage 14 V, plate spacing of 1.0 cm, electrolyte concentration of 0.35 mol/L, reaction time of 120 min, pH value of 10.The Ti/PANI/PbO2-Ce electrode showed good electrocatalytic performance.

Abstract Advanced oxidation processes are the most efficient tool to thwart the overaccumulation of harmful organic compounds in the environment. In this direction bioinspired metal complexes may be a viable solution for oxidative degradations in water. However, their synthesis is often elaborated and their scalability consequently low. This study presents alternative easy-to-synthesize bioinspired metal complexes to promote degradations in water. The metals employed were iron and manganese ions, hence cheap and highly accessible ions. The complexes were tested toward Phenol, Estrone, Triclosan, Oxybenzone, Diclofenac, Carbamazepine, Erythromycin, Aspartame, Acesulfame K, Anisole and 2,4-Dinitrotoluene. The reaction favoured electron-rich compounds reaching a removal efficiency of over 90%. The central ion plays a crucial role. Specifically, Mn(II) induces a non-radical pathway while iron ions a predominant radical one (⋅OH is predominant). The iron systems resulted more versatile toward contaminants, while the manganese ones showed a higher turn-over number, hence higher catalytic behaviour.

Qianyu Bai,1,* Yichi Zhang,1,* Runqiu Cai,1 Haiyan Wu,1 Huiqun Fu,2 Xuemei Zhou,2 Jie Chai,3 Xuepeng Teng,3 Tianlong Liu1 1National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agriculture University, Beijing, People’s Republic of China; 2 101 Institute of the Ministry of Civil Affairs, Beijing, People’s Republic of China; 3Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xuemei Zhou, 101 Institute of the Ministry of Civil Affairs, South Fourth Ring West Road No.188, Beijing, 100070, Email zxmcaur@126.com; Tianlong Liu, College of Veterinary Medicine, China Agriculture University, Yuanmingyuan West Road No. 2, Beijing, 100193, Email liutianlong@cau.edu.cnBackground: In the past decades, antimicrobial resistance (AMR) has been a major threat to global public health. Long-term, chronic otitis media is becoming more challenging to treat, thus the novel antibiotic alternative agents are much needed.Methods: ZnO@TiO2@AMP (ATZ NPs) were synthesized through a solvothermal method and subjected to comprehensive characterization. The in vitro and in vivo antibacterial effect and biocompatibility of ATZ NPs were evaluated. For the antibacterial mechanism exploration, we utilized the Electron Paramagnetic Resonance (EPR) Spectrometer to detect and analyze the hydroxyl radicals produced by ATZ NPs.Results: ATZ NPs exhibited a spherical structure of 99.85 nm, the drug-loading rate for ZnO was 20.73%, and AMP within ATZ NPs was 41.86%. Notably, the Minimum Inhibitory Concentration (MIC) value of ATZ NPs against Staphylococcus aureus (S. aureus), methicillin-resistant Staphylococcus aureus (MRSA), and Streptococcus pneumoniae (S. pneumoniae) were 10 μg/mL, and Minimum Bactericidal Concentration (MBC) value of ATZ NPs against S. aureus, and S. pneumoniae were 50 μg/mL. In comparison to the model group, the treatment of otitis media with ATZ NPs significantly reduces inflammatory exudation in the middle ear cavity, with no observable damage to the tympanic membrane. Both in vivo and in vitro toxicity tests indicating the good biocompatibility of ATZ NPs. Moreover, EPR spectroscopy results highlighted the superior ability of ATZ NPs to generate hydroxyl radicals (·OH) compared to ZnO NPs.Conclusion: ATZ NPs exhibited remarkable antibacterial properties both in vivo and in vitro. This innovative application of advanced ATZ NPs, bringing great promise for the treatment of otitis media.Keywords: nanoparticles, otitis media, zinc oxide, mesoporous titanium dioxide, antimicrobial peptide, antimicrobial, hydroxyl radical

Phenolic compounds are industrially versatile chemicals that have been successfully produced in microbial cell factories. Unfortunately, most phenolic compounds are highly toxic to cells in specific cellular environments or above a particular concentration because they form a complex with iron and promote hydroxyl radical production in Fenton reactions, resulting in the ferroptosis of cells. Here, we demonstrated that overexpression of efflux pumps and porins, including porins LamB and OmpN, and efflux pumps EmrAB, MdtABC, and SrpB, can enhance Escherichia coli phloroglucinol (PG) tolerance by inhibiting the generation of hydroxyl radicals. In addition, LamB and OmpN overexpression improved the bioproduction of PG. Furthermore, efflux pumps and porins can enhance bacterial tolerance to various phenolic compounds, including phenol, catechol, resorcinol, pyrogallol, and 2-naphthol. LamB and MdtABC confer a generalized tolerance to phenols. However, EmrAB, OmpN, and SrpB showed inconsistent effects of bacterial tolerance to different phenolic compounds. Our results will theoretically support the construction of phenolic compound-tolerant bacteria strains, which should be more efficient in the biosynthesis of phenols.

Photochemical oxidation is usually used for mild surface treatment rather than graphene patterning and is acknowledged to be far inferior to the traditional reactive ion etching. Some strategies have even been taken gradually to widen its applications, but the low efficiency makes it a big challenge. In this study, we report a way to pattern graphene in a highly efficient, anisotropic, and clean way by the H2O-based photochemical oxidation under irradiation of the xenon excimer lamp (λ = 172 nm). In a gradient magnetic field, the photodissociated paramagnetic OH-(X2Π) and H-(12S) radicals drift directionally toward graphene at a speed of wind. The anisotropic photochemical etching is tunable and has an etching rate exceeding 21 nm/min, applicable to making higher quality graphene micro/nanostructures under shadow masks. When combined with the traditional e-beam lithography, the photoinduced cross-linking of poly-(methyl methacrylate) 495 resist leads to fabricating clean graphene patterns by peeling off the mask, even removing the initial organic residues. The surface chemical analyses and first-principles calculation reveal that the directional OH-(X2Π) radical plays a vital role in etching graphene. This study opens up an avenue of photochemical oxidation for material functionalization, etching, and clean patterning. [ABSTRACT FROM AUTHOR]

The hydroxyl radical (OH) largely controls the tropospheric self-cleansing capacity by reacting with gases harmful to the environment and human health. OH concentrations are determined locally by competing production and loss processes. Lacking strong observational constraints, models differ in how they balance these processes, such that the sign of past and future OH changes is uncertain. In a warmer climate, OH production will increase due to its water vapor dependence, partially offset by faster OH-methane loss. Weather-sensitive emissions will also likely increase, although their net impact on global mean OH depends on the balance between source (nitrogen oxides) and sink (reactive carbon) gases. Lightning activity increases OH, but its response to climate warming is of uncertain sign. To enable confident projections of OH, we recommend efforts to reduce uncertainties in kinetic reactions, in measured and modeled OH, in proxies for past OH concentrations, and in source and sink gas emissions. OH is strongly modulated by internal climate variability despite its lifetime of a few seconds at most, with implications for interpreting trends in methane. Improved kinetic constraints on key reactions would strengthen confidence in regional and global OH budgets, and in the response of OH to climate change. Future OH changes will depend on uncertain and compensating processes involving weather-sensitive chemistry and emissions, plus human choices. Technological solutions to climate change will likely impact tropospheric oxidizing capacity and merit further study prior to implementation. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) calculation at the M06-2X/6-311+G(d,p) level was carried out to investigate aqueous degradation reactions of neutral and anionic forms of flumequine (FLU(N) and FLU(A)) induced by hydroxyl () and sulfate radicals (), including () addition (ADD), H atom abstraction (HAA) and single electron transfer (SET). The oxidation performance of and as an oxidant was analyzed. The computational results indicated that the degradation reactions of FLU(N) and FLU(A) involving () have some common features, namely, two ADD pathways involving C2 and C4 positions or C1 and C2 atoms in all six addition reactions are kinetically the most favorable, while the ADD pathway related to C3 atom is always the most unfavorable. Two HAA pathways associated with C7 and C9 atoms are the most advantageous in all HAA reactions. Moreover, the ADD pathway involving a C(sp2)−H bond is always easier to proceed than the HAA channel related to the same C atom. In addition, all SET reactions between FLU(N) or FLU (A) and () were found to have the highest Gibbs free energy of activation (ΔrG≠) compared with other parallel channels, and hence could be ruled out from the degradation mechanism of FLU. In most cases, the ADD pathway is the most favorable of all possible reaction channels. The reactivity of FLU(A) was found to be higher than that of FLU(N). Compared with , is a stronger oxidant in degrading FLU(N). However, the opposite situation can be observed for degradation of FLU(A). Hydroxylation and ring-opening of quinolone ring are important subsequent processes for favorable ADD and HAA intermediates. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes are the most efficient tool to thwart the overaccumulation of harmful organic compounds in the environment. In this direction bioinspired metal complexes may be a viable solution for oxidative degradations in water. However, their synthesis is often elaborated and their scalability consequently low. This study presents alternative easy-to-synthesize bioinspired metal complexes to promote degradations in water. The metals employed were iron and manganese ions, hence cheap and highly accessible ions. The complexes were tested toward Phenol, Estrone, Triclosan, Oxybenzone, Diclofenac, Carbamazepine, Erythromycin, Aspartame, Acesulfame K, Anisole and 2,4-Dinitrotoluene. The reaction favoured electron-rich compounds reaching a removal efficiency of over 90%. The central ion plays a crucial role. Specifically, Mn(II) induces a non-radical pathway while iron ions a predominant radical one (⋅OH is predominant). The iron systems resulted more versatile toward contaminants, while the manganese ones showed a higher turn-over number, hence higher catalytic behaviour. [ABSTRACT FROM AUTHOR]

Traditional H2O2 cleavage mediated by macroscopic electron transfer (MET) not only has low utilization of H2O2, but also sacrifices the stability of catalysts. We present a non‐redox hydroxyl‐enriched spinel (CuFe2O4) catalyst with dual Lewis acid sites to realize the homolytic cleavage of H2O2. The results of systematic experiments, in situ characterizations, and theoretical calculations confirm that tetrahedral Cu sites with optimal Lewis acidity and strong electron delocalization can synergistically elongate the O−O bonds (1.47 Å → 1.87 Å) in collaboration with adjacent bridging hydroxyl (another Lewis acid site). As a result, the free energy of H2O2 homolytic cleavage is decreased (1.28 eV → 0.98 eV). H2O2 can be efficiently split into ⋅OH induced by hydroxyl‐enriched CuFe2O4 without MET, which greatly improves the catalyst stability and the H2O2 utilization (65.2 %, nearly 2 times than traditional catalysts). The system assembled with hydroxyl‐enriched CuFe2O4 and H2O2 affords exceptional performance for organic pollutant elimination. The scale‐up experiment using a continuous flow reactor realizes long‐term stability (up to 600 mL), confirming the tremendous potential of hydroxyl‐enriched CuFe2O4 for practical applications. [ABSTRACT FROM AUTHOR]

Hydroxyl radical (•OH), a highly reactive oxygen species (ROS), is assumed as one of the most aggressive free radicals. This radical has a detrimental impact on cells as it can react with different biological substrates leading to pathophysiological disorders, including inflammation, mitochondrion dysfunction, and cancer. Quantification of this free radical in‐situ plays critical roles in early diagnosis and treatment monitoring of various disorders, like macrophage polarization and tumor cell development. Luminescence analysis using responsive probes has been an emerging and reliable technique for in‐situ detection of various cellular ROS, and some recently developed •OH responsive nanoprobes have confirmed the association with cancer development. This paper aims to summarize the recent advances in the characterization of •OH in living organisms using responsive nanoprobes, covering the production, the sources of •OH, and biological function, especially in the development of related diseases followed by the discussion of luminescence nanoprobes for •OH detection. [ABSTRACT FROM AUTHOR]

It is well-known that highly reactive hydroxyl radicals (HO) can be produced by the classic Fenton system and our recently discovered haloquinone/H2O2 system, but rarely from thiol-derivatives. Here, we found, unexpectedly, that HO can be generated from H2O2 and thiourea dioxide (TUO2), a widely used and environmentally friendly bleaching agent. A carbon-centered radical and sulfite were detected and identified as the transient intermediates, and urea and sulfate as the final products, with the complementary application of electron spin-trapping, oxygen-18 isotope labeling coupled with HPLC/ MS analysis. Density functional theory calculations were conducted to further elucidate the detailed pathways for HO production. Taken together, we proposed that the molecular mechanism for HO generation by TUO2/H2O2: TUO2 tautomerizes from sulfinic acid into ketone isomer (TUO2-K) through proton transfer, then a nucleophilic addition of H2O2 on the S atom of TUO2-K, forming a S-hydroperoxide intermediate TUO2-OOH, which dissociates homolytically to produce HO. Our findings represent the first experimental and computational study on an unprecedented new molecular mechanism of HO production from simple thiol-derived sulfinic acids, which may have broad chemical, environmental, and biomedical significance for future research on the application of the well-known bleaching agent and its analogs. [ABSTRACT FROM AUTHOR]

It is well-known that highly reactive hydroxyl radicals (HO) can be produced by the classic Fenton system and our recently discovered haloquinone/H2O2 system, but rarely from thiol-derivatives. Here, we found, unexpectedly, that HO can be generated from H2O2 and thiourea dioxide (TUO2), a widely used and environmentally friendly bleaching agent. A carbon-centered radical and sulfite were detected and identified as the transient intermediates, and urea and sulfate as the final products, with the complementary application of electron spin-trapping, oxygen-18 isotope labeling coupled with HPLC/ MS analysis. Density functional theory calculations were conducted to further elucidate the detailed pathways for HO production. Taken together, we proposed that the molecular mechanism for HO generation by TUO2/H2O2: TUO2 tautomerizes from sulfinic acid into ketone isomer (TUO2-K) through proton transfer, then a nucleophilic addition of H2O2 on the S atom of TUO2-K, forming a S-hydroperoxide intermediate TUO2-OOH, which dissociates homolytically to produce HO. Our findings represent the first experimental and computational study on an unprecedented new molecular mechanism of HO production from simple thiol-derived sulfinic acids, which may have broad chemical, environmental, and biomedical significance for future research on the application of the well-known bleaching agent and its analogs. [ABSTRACT FROM AUTHOR]

A one-step solvothermal synthesis technique was employed to fabricate C60/MIL-101(Fe) composites. The C60/MIL-101(Fe) composites showed a better performance in the degradation of methylene blue (MB) and tetracycline hydrochloride (TCH) when compared to MIL-101(Fe) in the photo-Fenton system, which can be credited to the charge transfer and separation facilitated by the addition of C60. Results showed that C60/MIL-101(Fe) had the capacity to nearly completely eliminate TCH and MB over a broad pH range. The catalysts demonstrated remarkable catalytic degradation on various organic pollutants and water samples. Through active substance quenching experiments and EPR, it was determined that hydroxyl radical (·OH) is the main factor in the photocatalytic reaction process. [ABSTRACT FROM AUTHOR]

Benzene is the typical volatile organic compound (VOC) of indoor and outdoor air pollution, which harms human health and the environment. Due to the stability of their aromatic structure, the catalytic oxidation of benzene rings in an environment without an external energy input is difficult. In this study, the efficient degradation of benzene at room temperature was achieved by constructing Ag and Ni bimetallic active site catalysts (AgNi/BCN) supported on boron–carbon–nitrogen aerogel. The atomic-scale Ag and Ni are uniformly dispersed on the catalyst surface and form Ag/Ni-C/N bonds with C and N, which were conducive to the catalytic oxidation of benzene at room temperature. Further catalytic reaction mechanisms indicate that benzene reacted with ·OH to produce R·, which reacted with O2 to regenerate ·OH. Under the strong oxidation of ·OH, benzene was oxidized to form alcohols, carboxylic acids, and eventually CO2 and H2O. This study not only significantly reduces the energy consumption of VOC catalytic oxidation, but also improves the safety of VOC treatment, providing new ideas for the low energy consumption and green development of VOC treatment. [ABSTRACT FROM AUTHOR]

The present work used the Behnajady–Modirshahla–Ghanbary (BMG) kinetic model to determine the initial reaction rates (1/m), which were used to calculate the activation energy (Ea) from the decolorization of synthetic dyes by Fenton processes (Fe2+/H2O2, Fe2+/H2O2/reducer and Fe3+/H2O2/reducer). When increasing the temperature and adding Fe3+-reducing compounds (3-Hydroxyanthranilic Acid, Hydroquinone, Gallic Acid, Cysteine or Ascorbic Acid), increases in the 1/m values were observed. When studying the classical Fenton reaction (Fe2+/H2O2), almost all added reducers had decreased Ea. For example, 3-Hydroxyanthranilic Acid decreased the Ea related to the decolorization of the Phenol Red dye by 39%, while Ascorbic Acid decreased the Ea of Safranin T decolorization by 23%. These results demonstrate that the reducers increased the initial reaction rate and decreased the energy barrier to improve Fenton-based decolorization of dyes. When comparing the reaction systems in presence of reducers (Fen+/H2O2/reducer), the reactions initially containing Fe2+ presented lower Ea than reactions catalyzed by Fe3+. That way, the activation energy obtained through the 1/m values of the BMG model highlighted the pro-oxidant effect of reducers in Fenton processes to degrade dyes. [ABSTRACT FROM AUTHOR]

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Micro–nanobubbles (MNBs) can generate ·OH in situ, which provides a new idea for the safe and efficient removal of pollutants in water supply systems. However, due to the difficulty in obtaining stable MNBs, the generation efficiency of ·OH is low, and the removal efficiency of pollutants cannot be guaranteed. This paper reviews the application research of MNB technology in water security from three aspects: the generation process of MNBs in water, the generation rule of ·OH during MNB collapse, and the control mechanisms of MNBs on pollutants and biofilms. We found that MNB generation methods are divided into chemical and mechanical (about 10 kinds) categories, and the instability of the bubble size restricts the application of MNB technology. The generation of ·OH by MNBs is affected by the pH, gas source, bubble size, temperature, and external stimulation. And the pH and external stimulus have more influence on ·OH generation in situ than the other factors. Adjusting the pH to alkaline or acidic conditions and selecting ozone or oxygen as the gas source can promote ·OH generation. MNB collapse also releases a large amount of energy, during which the temperature and pressure can reach 3000 K and 5 Gpa, respectively, making it efficient to remove ≈90% of pollutants (i.e., trichloroethylene, benzene, and chlorobenzene). The biofilm can also be removed by physical, chemical, and thermal effects. MNB technology also has great application potential in drinking water, which can be applied to improve water quality, optimize household water purifiers, and enhance the taste of bottled water. Under the premise of safety, after letting people of different ages taste water samples, we found that compared with ordinary drinking water, 85.7% of people think MNB water is softer, and 73.3% of people think MNB water is sweeter. This further proves that MNB water has a great prospect in drinking water applications. This review provides innovative theoretical support for solving the problem of drinking water safety. [ABSTRACT FROM AUTHOR]

The combined effects of electrolysis and ultrasound on the population of E. coli bacteria in an aqueous solution of sodium sulfate have been studied. The kinetics of bacterial inactivation with this method for water purification have been determined. It has been shown that the combined effect of ultrasonic and electrochemical treatment of an aqueous solution significantly increased the rate of bacterial inactivation. It has been suggested that hydroxyl radicals formed during combined treatment are responsible for the death of bacteria. A correlation has been found between the rate of formation of hydroxyl radicals and the rate of inactivation of bacteria. [ABSTRACT FROM AUTHOR]

The catalyst of Cu-Ce/γ-Al2O3 was prepared by the sol–gel method, and its catalytic degradation ability of phenol in a heterogeneous Fentonlike system was studied. Results show that the catalyst exhibited excellent catalytic degradation performance for phenol at a calcination time of 6 h, calcination temperature of 600 °C, and a Cu/Ce molar ratio of 2:1. Under conditions of catalyst dosage of 1.2 g/L, H2O2 concentration of 45 mmol/L, and pH of 6, the phenol removal rate reached 98%. Subsequently, the catalyst of Cu-Ce/γ-Al2O3 was characterized by X-ray difraction analysis (XRD) and scanning electron microscopy (SEM). Results showed that Cu and Ce were successfully loaded onto the surface of alumina, and the catalyst has a honeycomb structure on the surface. Our data suggest that •OH is likely the main active species, and the interaction between Ce and Cu increases the content of •OH in the solution, thereby promoting Fenton-like reactions. Our study hints at the potential for the application of Cu and Ce as active components, providing new insights for the design of Fenton-like catalysts. Furthermore, this study highlights the potential of Cu-Ce/γ-Al2O3 for Fenton-like degradation of phenol wastewater. [ABSTRACT FROM AUTHOR]

Nowadays, antibiotics are widely used, increasing the risk of contamination of the water body and further threatening human health. The traditional water treatment process is less efficient in degrading antibiotics, and the advanced oxidation process (AOPs) is cleaner and more efficient than the traditional biochemical degradation process. The combined ozone/peroxymonosulfate (PMS) advanced oxidation process (O3/PMS) based on sulfate radical (SO4•−) and hydroxyl radical (•OH) has developed rapidly in recent years. The O3/PMS process has become one of the most effective ways to treat antibiotic wastewater. The reaction mechanism of O3/PMS was reviewed in this paper, and the research and application progress of the O3/PMS process in the degradation of antibiotics in drinking water and wastewater effluent were evaluated. The operation characteristics and current application range of the process were summarized, which has a certain reference value for further research on O3/PMS process. [ABSTRACT FROM AUTHOR]

Hydroxyl radical (•OH) detection is pivotal in medicine, biochemistry and environmental chemistry. Yet, electrochemical method–specific detection is challenging because of hydroxyl radicals' high reactivity and short half-life. In this study, we aimed to modify the electrode surface with a specific recognition probe for •OH. To achieve this, we conducted a one-step hydrothermal process to fabricate a CoZnMOF bimetallic organic framework directly onto conductive graphite paper (Gp). Subsequently, we introduced salicylic acid (SA) and methylene blue (MB), which easily penetrated the pores of CoZnMOF. By selectively capturing •OH by SA and leveraging the electrochemical signal generated by the reaction product, we successfully developed an electrochemical sensor Gp/CoZnMOF/SA + MB. The prepared sensor exhibited a good linear relationship with •OH concentrations ranging from 1.25 to 1200 nM, with a detection limit of 0.2 nM. Additionally, the sensor demonstrated excellent reproducibility and accuracy due to the incorporation of an internal reference. It exhibited remarkable selectivity for •OH detection, unaffected by other electrochemically active substances. The establishment of this sensor provides a way to construct MOF-modified sensors for the selective detection of other reactive oxygen species (ROS), offering a valuable experimental basis for ROS-related disease research and environmental safety investigations. [ABSTRACT FROM AUTHOR]

In most of advanced oxidation processes (AOPs) used to destroy harmful organic chemicals in water/wastewater hydroxyl radical (•OH) reactions oxidize (increasing the oxygen/carbon ratio in the molecules) and mineralize (transforming them to inorganic molecules, H2O, CO2, etc.) these contaminants. In this paper, we used the radiolysis of water to produce •OH and characterised the rate of oxidation and mineralization by the dose dependences of the Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) content values. Analysis of the dose dependences for 34 harmful organic compounds showed large differences in the oxidation and mineralization rates and these parameters are characteristic to the given group of chemicals. E.g., the rate of oxidation is relatively low for fluoroquinolone antibiotics; it is high for β-blocker medicines. Mineralization rates are low for both fluoroquinolones and β-blockers. The one-electron-oxidant •OH in most cases induces two − four-electron-oxidations. Most of the degradation takes place gradually, through several stable molecule intermediates. However, based on the results it is likely, that some part of the oxidation and mineralization takes place parallel. The organic radicals formed in •OH reactions react with several O2 molecules and release several inorganic fragments during the radical life cycle.

The activation of ferroptosis is being pursued in cancer research as a strategy to target apoptosis-resistant cells. By contrast, in various diseases that affect the cardiovascular system, kidneys, liver, and central and peripheral nervous systems, attention is directed toward interventions that prevent ferroptotic cell death. Mechanistic insights into both research areas stem largely from studies using cellular in vitro models. However, intervention strategies that show promise in cellular test systems often fail in clinical trials, which raises concerns regarding the predictive validity of the utilized in vitro models.In this study, the human LUHMES cell line, which serves as a model for human dopaminergic neurons, was used to characterize factors influencing the activation of ferroptosis. Erastin and RSL-3 induced cell death that was distinct from apoptosis. Parameters such as the differentiation state of LUHMES cells, cell density, and the number and timing of medium changes were identified as determinants of sensitivity to ferroptosis activation. In differentiated LUHMES cells, interventions at mechanistically divergent sites (iron chelation, coenzyme Q10, peroxidase mimics, or inhibition of 12/15-lipoxygenase) provide almost complete protection from ferroptosis. LUHMES cells allowed the experimental modulation of intracellular iron concentrations and demonstrated a correlation between intracellular iron levels, the rate of lipid peroxidation, as well as the sensitivity of the cells to ferroptotic cell death.These findings underscore the importance of understanding the various factors that influence ferroptosis activation and highlight the need for well-characterized in vitro models to enhance the reliability and predictive value of observations in ferroptosis research, particularly when translating findings into in vivo contexts.