Generation Of Reactive Species Research Articles

Efflux pumps mediate changes to fundamental bacterial physiology via membrane potential.

Efflux pumps are well known to be an important mechanism for removing noxious substances such as antibiotics from bacteria. Given that many antibiotics function by accumulating inside bacteria, efflux pumps contribute to resistance. Efflux pump inactivation is a potential strategy to combat antimicrobial resistance, as bacteria would not be able to pump out antibiotics. We recently discovered that the impact of loss of efflux function is only apparent in actively growing cells. We demonstrated that the global transcriptome of Salmonella Typhimurium is drastically altered during slower growth leading to stationary-phase cells having a remodeled, less permeable envelope that prevents antibiotics entering the cell. Here, we investigated the effects of deleting the major efflux pump of Salmonella Typhimurium, AcrB, on global gene transcription across growth. We revealed that an acrB knockout entered stationary phase later than the wild-type strain SL1344 and displayed increased and prolonged expression of genes responsible for anaerobic energy metabolism. We devised a model linking efflux and membrane potential, whereby deactivation of AcrB prevents influx of protons across the inner membrane and thereby hyperpolarization. Knockout or deactivation of AcrB was demonstrated to increase membrane potential. We propose that the global transcription regulator ArcBA senses changes to the redox state of the quinol pool (linked to the membrane potential of the bacterium) and coordinates the shift from exponential to stationary phase via the key master regulators RpoS, Rsd, and Rmf. Inactivation of efflux pumps therefore influences the fundamental physiology of Salmonella, with likely impacts on multiple phenotypes.IMPORTANCEWe demonstrate for the first time that deactivation of efflux pumps brings about changes to gross bacterial physiology and metabolism. Rather than simply being a response to noxious substances, efflux pumps appear to play a key role in maintenance of membrane potential and thereby energy metabolism. This discovery suggests that efflux pump inhibition or inactivation might have unforeseen positive consequences on antibiotic activity. Given that stationary-phase bacteria are more resistant to antibiotic uptake, late entry into stationary phase would prolong antibiotic accumulation by bacteria. Furthermore, membrane hyperpolarization could result in increased generation of reactive species proposed to be important for the activity of some antibiotics. Finally, changes in gross physiology could also explain the decreased virulence of efflux mutants.

Impact of metal ions on PMS/Cl− disinfection efficacy: Enhancing or impeding microbial inactivation?

Peroxymonosulfate (PMS) is an eco-friendly disinfectant gaining attention. This study examined the influence of metal ions (Co(II), Cu(II), Fe(II)) on PMS disinfection with chloride ions (Cl−) against waterborne microorganisms, encompassing both bacteria and fungal spores. The findings elucidated that metal ions augment the inactivation of bacteria in the PMS/Cl− system while concurrently impeding the inactivation of fungal spores. Specifically, the PMS/Co(II)/Cl− process increased E. coli inactivation rates by 2.25 and 2.75 times compared to PMS/Co(II) and PMS/Cl−, respectively. Conversely, PMS/Me(II)/Cl− generally exhibited a diminished inactivation capacity against the three fungal spores compared to PMS/Cl−, albeit surpassing the efficacy of PMS/Me(II). For instance, the inactivation levels of A. niger by PMS/Cl−, PMS/Cu(II)/Cl−, and PMS/Cu(II) are 4.47-log, 1.92-log, and 0.11-log, respectively. Notably, fungal spores demonstrated a substantially higher resistance to disinfectants compared to bacteria. Differences in microbial susceptibility were linked to cell wall structure, composition, antioxidant defenses, and reactive species generation, such as hydroxyl radicals (•OH), sulfate radicals (SO4•−), and reactive chlorine species (RCS). This study demonstrated the novel and unique phenomenon of metal ions' dual role in modulating the PMS/Cl− disinfection process, which has not been reported before and has important implications for the field of water treatment.

Unraveling the Impact of Oxygen Vacancy on Electrochemical Valorization of Polyester Over Spinel Oxides.

Electrochemical upcycling of end-of-life polyethylene terephthalate (PET) using renewable electricity offers a route to generate valuable chemicals while processing plastic wastes. However, it remains a huge challenge to design an electrocatalyst with reliable structure-property relationships for PET valorization. Herein, spinel Co3O4 with rich oxygen vacancies for improved activity toward formic acid (FA) production from PET hydrolysate is reported. Experimental investigations combined with theoretical calculations reveal that incorporation of VO into Co3O4 not only promotes the generation of reactive hydroxyl species (OH*) species at adjacent tetrahedral Co2+ (Co2+ Td), but also induces an electronic structure transition from octahedral Co3+ (Co3+ Oh) to octahedral Co2+ (Co2+ Oh), which typically functions as highly-active catalytic sites for ethylene glycol (EG) chemisorption. Moreover, the enlarged Co-O covalency induced by VO facilitates the electron transfer from EG* to OH* via Co2+ Oh-O-Co2+ Td interaction and the following C─C bond cleavage via direct oxidation with a glyoxal intermediate pathway. As a result, the VO-Co3O4 catalyst exhibits a high half-cell activity for EG oxidation, with a Faradaic efficiency (91%) and productivity (1.02mmol cm-2 h-1) of FA. Lastly, it is demonstrated that hundred gram-scale formate crystals can be produced from the real-world PET bottles via two-electrode electroreforming, with a yield of 82%.

Photo-assisted conversion of tetracycline in regulated persulfate system: Multiple roles of natural dissolved organic matter

Advanced oxidation processes (AOPs) using persulfate system can effectively remove organic pollutants. However, dissolved organic matter (DOM) has multiple effects on AOPs efficiency, and the influence of DOMs from natural sources on AOPs is still unclear. In this study, we explored the effects of soil DOM (SDOM) and fertilizer DOM (FDOM) on tetracycline (TC) removal by persulfate systems. DOMs introduction decreased light transmittance, slightly increased the pH of the systems, and destroyed original adsorption–desorption equilibrium. SDOM promoted most reactive species generation in the initial stage, thus improving the initial TC degradation rate. However, introduction of SDOM and FDOM increased the final TC residual rate. FDOM produced more obvious inhibitory effects on TC degradation. The final TC residual rates in systems containing 7.5 and 15 mg L-1 FDOM (F7.5-TC-PS and F15-TC-PS, respectively) were 25.85 % and 25.52 %, respectively. The inhibitory effects of FDOM on TC degradation were related to the combination between TC and FDOM, with humic acid-like component in FDOM being the main contributor. Besides, the main components in DOMs underwent transformation in the persulfate systems. This study sought to provide insights into the regulatory effects of DOM on TC photo-assisted conversion by AOPs.

Activated carbon-mediated arsenopyrite oxidation and arsenic immobilization: ROS formation and its role

The oxidative dissolution of arsenopyrite (FeAsS) is a significant source of arsenic contamination in nature. Activated biochar (AC), a widely used environmental remediation agent, is prevalent in ecosystems and participated in various geochemical processes of arsenic and iron-containing sulfide minerals. However, the impact of AC-arsenopyrite association on reactive oxidation species (ROS) generation and its contribution to As transformation were rarely explored. Here, ROS formation and the redox conversion of As during the interaction between AC and arsenopyrite were investigated. AC-mediated arsenopyrite oxidation was a two-stage process. At stage I, the heterogeneous electron transfer from arsenopyrite facilitated O2 reduction on AC, enhancing arsenopyrite dissolution and ROS formation. TBA, PBQ and catalase inhibited 86.40%, 79.39% and 49.66% of As(III) oxidation, respectively, indicating indicated that HO˙, (O2•)- and H2O2 were responsible for As(III) oxidation. However, at stage II, the mobility of As was highly restricted, especially increasing AC addition. Besides adsorption, AC retained appreciable As through catalyzing insoluble ferric arsenate formation and growth by promoting Fe(II) and As(III) oxidation and functioning as nuclei. These findings deepen our understanding of the coupling behavior of AC-arsenopyrite and its influence on geochemical cycling of arsenic in mined surroundings, which has important implications for mitigating arsenic pollution.

Tailoring performance for biomass tar reforming using magnetically assisted gliding arc discharges

Gliding arc discharge (GAD) holds significant potential for energy and environmental applications, particularly in biomass tar reforming. In this study, we developed two GAD reactors coupled with a magnetic field for biomass tar reforming. The reactors were designed with two different configurations by varying the magnetic field direction relative to the electrodes: magnetically accelerated gliding arc discharge (MAGAD) and magnetically stabilized gliding arc discharge (MSGAD). The reforming performance and discharge characteristics of these two configurations were systematically evaluated and compared with those of a normal GAD (NGAD). MAGAD demonstrated superior reforming performance, achieving the highest conversion for toluene (71.4 %) and phenol (87.5 %), as well as the highest yields of H2 (22.4 %) and C2H2 (12.6 %) at a magnetic field intensity of 133 mT. In contrast, MSGAD achieved the highest energy yield (47.1 g/kWh) but exhibited lower tar conversion due to reduced discharge power. In the MAGAD system, the magnetic field generates a synergistic effect between the Lorenz force and gas thrust, accelerating and elongating the arc along the electrodes. This results in increased discharge power and frequency, as well as an expanded discharge region. This leads to the generation of more reactive species, which enhances the breakdown of benzene rings into short-chain hydrocarbons and reduces the formation of liquid byproducts. These findings demonstrate the potential of manipulating magnetic fields to optimize GAD systems for efficient biomass tar reforming, offering a promising strategy to improve the performance of plasma-based chemical reactions.

Cold plasma/alkaline pretreatment facilitates corn stalk fractionation and valorization towards zero-waste approach

The present study employed alkaline hydrogen peroxide pretreatment coupled with cold plasma for corn stalk’s complex biopolymers fractionation and valorization through enzymatic hydrolysis. This hurdle approach enables the prolonged generation of reactive oxidative species, initiating chemical reactions otherwise hardly possible under ambient conditions. A delignification rate between 76±1 and 86±2 % was obtained under different process parameters in a significantly shorter time compared to conventional alkaline pretreatment. Up to 94±4 % of cellulose in treated biomass was converted to glucose after enzymatic hydrolysis, achieving around 3.5 times higher glucose yield than the raw biomass. Different spectroscopic analyses confirmed specific alterations in the structure of the lignin-rich fraction caused by cold plasma. Micro- and nanoscale lignin particles obtained were rich in total phenolic content, reaching up to 140±20 and 107±12 µg gallic acid equivalents (GAE) per mg of lignin, respectively. The proposed concept of corn stalk fractionation through biorefinery can open new opportunities for valorizing different agricultural waste types.

NOX1-mediated oxidative stress induces chondrocyte ferroptosis by inhibiting the Nrf2/HO-1 pathway

Osteoarthritis (OA) is a common joint disease associated with the aging of the population, and it reduces the quality of life of patients. It is characterized by the destruction of articular cartilage and the secretion of inflammatory cytokines. Owing to the unclear pathogenesis of OA, current treatment methods have significant limitations. Oxidative stress has been revealed to play an important role in the development of OA. Our experiments indicated that the levels of GSH decreased and the level of MDA increased in chondrocytes, which induced ferroptosis in chondrocytes in OA. We also revealed that ferroptosis was the main mechanism of cartilage destruction caused by the addition of the ferroptosis activator erastin and the ferroptosis inhibitor ferrostatin-1. NOX1 is the main modulator of oxidative stress by increasing the generation of reactive oxidative species (ROS). We suppressed the expression of NOX1 in chondrocytes through cell transfection. The expression of collagen II and MMP13, and the secretion of IL-1β and TNF-α were reversed. An increase in the mitochondrial membrane potential and a decrease in the level of intracellular ROS indicate an improvement in oxidative damage. Additionally, we determined the effect of the Nrf2/HO-1 pathway on NOX1-mediated chondrocyte injury. We found that NOX1 inhibited the expression of Nrf2/HO-1, but the activation of Nrf2 improved the oxidative damage to chondrocytes in vivo and vitro. This study revealed that NOX1-mediated oxidative stress induces chondrocyte ferroptosis by inhibiting the Nrf2/HO-1 pathway. Our findings contribute to revealing the pathogenesis of OA, providing targets for drug design and optimizing the clinical treatment of OA.

Fluorocarbon polymers mediated contact-electro-catalysis activating peroxymonosulfate for emerging pollutants degradation: The key role of fluorine density in electron transfer

Peroxymonosulfate-based advanced oxidation processes (PMS-AOPs) have been extensively investigated for environmental pollutants remediation. Moreover, systematic exploration of catalysts with the high-efficient, cost-effective, and environment-durable properties has been usually recognized as the crucial pathway to boost PMS activation and enhance pollutants degradation. Herein, we demonstrated that the inert fluorocarbon polymers (FCPs) mediated contact-electro-catalysis (CEC) under ultrasound can be utilized to activate PMS (FCPs/PMS/US) for high-efficient degradation and detoxication of emerging pollutants (EPs). The catalytic EPs degradation process was dominant with 1O2 pathway, accompanied by radical pathways (•OH, SO4•−, and O2•−). Density functional theory calculations and correlation analysis provided strong evidence for the fluorine (–F) density-dependent electron transfer among H2O-FCPs-electron acceptors, which determined the generation of reactive oxidative species and EPs degradation rate in FCPs/PMS/US. Consequently, fluorinated ethylene propylene (FEP) with the highest –F density exhibited higher degradation rate of sulfadiazine (kobs = 0.043 min−1, at an FEP dosage of 0.25 g·L−1) compared to polytetrafluoroethylene and polyvinylidene fluoride. Besides, the FCPs/PMS/US system showed excellent stability, durability, and promising applicability for high-salinity seawater remediation, with the electrical energy per log order of 0.53 kWh·m−3. This study provided a novel route for PMS activation and stimulates further exploration of CEC for environmental remediation.

CuFeS2/GAC particle combined with electrochemical activation of persulfates for efficient degradation of carbamazepine

Electrochemically activated persulfate is a potential advanced oxidation process due to its advantages of environmental friendliness, high efficiency, and convenient operation. An Fe–Cu–S granular activated carbon (CuFeS2/GAC, abbreviated as FCSG) particles electrode was developed and applied to degrade carbamazepine (CBZ) combined with electrochemical activation of persulfate (E-PDS-FCSG) in this work. Compared to two-dimensional electrochemical process (E-PDS), the three-dimensional (3D) E-PDS-FCSG process exhibited higher removal efficiency of CBZ and lower energy consumption. The removal efficiency of CBZ and power consumption increased by 96% and reduced by 67%, respectively. Over 98% of CBZ removal rate was reached within 25 min. Apart from the same free radicals in two-dimensional electrochemical process, both Fe2+ and Cu+ on the surface of three-dimensional particle electrodes can directly activate PDS to produce SO4•–, and the existence of S2− strengthens the circulation of Fe3+/Fe2+ and Cu2+/Cu+. Furthermore, FCSG particle electrode can not only directly enhance the activation of PDS, but also accelerate the electron transfer, and then effectively promoting reactive species generation. LC-MS analysis showed that the main degradation pathways of CBZ involved decarbonylation, deamination, dealkylation, ring opening and mineralization. Moreover, after five cycle experiments, over 80% of CBZ removal rate could be achieved, demonstrating that the E-PDS-FCSG system had excellent electrocatalytic performance and good stability. These findings indicate that FCSG is a promising material and could be used as a particle electrode for removing organic pollutants from water.

Indoor air disinfection by non thermal atmospheric pressure plasma: a comparative study of performance in low and high humidity environments

Atmospheric pressure plasma (APP) has intrigued the interest of researchers for various applications such as disinfection, air purification, etc. In this context, a deeper understanding of the correlation between APP’s characteristics like discharge parameters, active species composition, and eradication of airborne microorganisms with varying relative humidity (RH) has been examined using a dielectric barrier discharge based atmospheric pressure plasma (DBD-APP) source. One of the electrodes of the developed DBD-APP source has been coated with TiO2 nanoparticles to enhance the generation of reactive species during the discharge process. The results show that, even with the same peak-to-peak applied voltage, the peak-to-peak current and discharge power decrease with increasing RH. Optical emission spectroscopy (OES) is used to determine the relative emission intensity of the reactive species, whereas spectrophotometry is used to quantify the reactive species produced by the plasma at various parameters. Instead of UV radiation, the plasma-produced highly energetic electrons activates the TiO2 nanoparticles for electron–hole pair generation. The geometry of the plasma device has played an important role in generating high energy electrons. From the developed DBD-APP source, the airborne microorganism’s disinfection efficiency of ∼95.8% and ∼98.7% has been achieved in the total bacterial counts (TBCs) and total fungal counts (TFCs) at an RH range of 70%–90%, in just 20 min of continuous operation. However, in the RH range of 20%–40%, the inactivation efficiency dropped to ∼78.8% and ∼87.5% for the TBCs and TFCs, respectively. The outcome indicates that higher humidity levels are better for indoor air purification using DBD-APP sources and that plasma with a circulation system can effectively disinfect indoor environments.

Activating peroxymonosulfate with MOF-derived NiO-NiCo2O4/titanium membrane for water treatment: A non-radical dominated oxidation mechanism

Traditional peroxymonosulfate (PMS) catalytic membranes dominated by radical pathways often face interference from complex components in water bodies. Herein, we employed a controlled electro-deposition technique to coat a Ni-Co metal–organic framework (MOF) precursor onto titanium hollow fiber membrane (THFM), followed by high-temperature calcination to synthesize a MOF-derived NiO-NiCo2O4/THFM (M−NNCO−THFM) PMS catalytic membrane. Then, the M−NNCO−THFM filtration integrated with PMS activation (MFPA process) for water treatment. Experimental results demonstrated that the M−NNCO−THFM MFPA process successfully achieved complete phenol (PE) removal via a non-radical-dominated degradation pathway, involving singlet oxygen (1O2) and electron transfer, while exhibiting wide pH adaptability and exceptional stability in complex water matrices. Mechanism analysis revealed that the electron transfer process was significantly enhanced by the MOF-derived heterojunction structure, which increased the flat-band potential from 0.39 eV to 0.56 eV, thereby facilitating efficient electron transfer for PE removal. The non-radical 1O2 pathway was primarily due to the cycling of metal valence states (Ni2+/Co3+), leading to the reduction of Co2+ and its reaction with PMS, resulting in the generation of reactive species. Furthermore, electrochemical measurements indicated that the M−NNCO−THFM exhibited lower charge transfer resistance and enhanced charge transfer efficiency compared to non-MOF-derived NNCO-THFM, corresponding to the superior catalytic performance and electrochemically active surface area of M−NNCO−THFM.

Holistic analysis of a gliding arc discharge using 3D tomography and single-shot fluorescence lifetime imaging

Gliding arc plasmas, a versatile form of non-thermal plasma discharges, hold great promise for sustainable chemical conversion in electrified industrial applications. Their relatively high temperatures compared to other non-thermal plasmas, reactive species generation, and efficient energy transfer make them ideal for an energy-efficient society. However, plasma discharges are transient and complex 3D entities influenced by gas pressure, mixture, and power, posing challenges for in-situ measurements of chemical species and spatial dynamics. Here we demonstrate a combination of innovative approaches, providing a comprehensive view of discharges and their chemical surroundings by combining fluorescence lifetime imaging of hydroxyl (OH) radicals with optical emission 3D tomography. This reveals variations in OH radical distributions under different conditions and local variations in fluorescence quantum yield with high spatial resolution from a single laser shot. Our results and methodology offer a multidimensional platform for interdisciplinary research in plasma physics and chemistry.

Cold atmospheric plasma-activated medium for potential ovarian cancer therapy.

Cold atmospheric plasma (CAP) has emerged as an innovative tool with broad medical applications, including ovarian cancer (OC) treatment. By bringing CAP in close proximity to liquids such as water or cell culture media, solutions containing reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated, called plasma-activated media (PAM). In this systematic review, we conduct an in-depth analysis of studies focusing on PAM interactions with biological substrates. We elucidate the diverse mechanisms involved in the activation of different media and the complex network of chemical reactions underlying the generation and consumption of the prominent reactive species. Furthermore, we highlight the promises of PAM in advancing biomedical applications, such as its stability for extended periods under appropriate storage conditions. We also examine the application of PAM as an anti-cancer and anti-metastatic treatment for OC, with a particular emphasis on its ability to induce apoptosis via distinct signaling pathways, inhibit cell growth, suppress cell motility, and enhance the therapeutic effects of chemotherapy. Finally, the future outlook of PAM therapy in biomedical applications is speculated, with emphasis on the safety issues relevant to clinical translation.

High-efficient M-NC single-atom catalysts for catalytic ozonation in water purification: Performance and mechanisms

Heterogeneous catalytic ozonation (HCO) holds promise in water purification but suffers from limited accessible metal sites, metal leaching, and unclear structure-activity relationships. This work reported M-NC (M=Co, Ni, Fe, and Mn) single-atom catalysts (SACs) with high atomic efficiency and minimal metal release. The new HCO systems, especially the Co-based system, exhibited impressive performance in various refractory contaminant removal, involving various reactive species generation, such as •OHads, •OHfree, *O, and 1O2. For sulfamethoxazole removal, the normalized kobs for Co-NC, Ni-NC, Fe-NC, and Mn-NC were determined as 13.53, 3.94, 3.55, and 4.13 min−1·mMmetal−1·g·m−2 correspondingly, attributed to the abundant acid sites, faster electron transfer, and lower energy required for O3 decomposition and conversion. The metal atoms and hydroxyl groups, individually serving as Lewis and Bronsted acid sites (LAS and BAS), were the primary centers for •OH generation and O3 adsorption. The relationships between active sites and both O3 utilization and •OH generation were found. LAS and BAS were responsible for O3 adsorption, while strong LAS facilitated O3 conversion into •OH. Theoretical calculations revealed the catalytic mechanisms involved O3→ *O→ *OO→ O3•−→ •OH. This work highlights the significance of SAC design for HCO and advances the understanding of atomic-level HCO behavior.

Electrocatalytically active and charged natural chalcopyrite for nitrate-contaminated wastewater purification extended to energy storage Zn-NO3− battery

Charged natural chalcopyrite (CuFeS2, Ncpy) was developed for a three-dimensional electrochemical nitrate reduction (3D ENO3−RR) system with carbon fiber cloth cathode and Ti/IrO2 anode and Zn-NO3− battery. The 3D ENO3−RR system with Ncpy particle electrodes (PEs) possessed superior nitrate removal of 95.6 % and N2 selectivity of 76 % with excellent reusability under a broad pH range of 2–13 involving heterogeneous and homogeneous radical mechanisms. The Zn-NO3− battery with Ncpy cathode delivered an open-circuit voltage of 1.03 V and a cycling stability over 210 h. It was found that Ncpy PEs functioned through self-oxidation, surface dynamic reconstruction (Cu1.02Fe1.0S1.72O1.66 to Cu0.61Fe1.0S0.27O2.98), intrinsic micro-electric field (CuI, S2− anodic and FeIII cathodic poles), and reactive species (•OH, SO4•−, 1O2, •O2− and •H) generation. Computational analyses reveal that CuFeS2(112) surface with the lowest surface energy preferentially exposes Fe and Cu atoms. Cu site is beneficial for reducing NO3− to NO2−, Fe and Fe−Cu dual sites are conducive to N2 selectivity, lowering the overall reaction barriers. It paves the way for selective NO3− reduction in wastewater treatment and can be further extended to energy storage devices by utilizing low-cost Ncpy.

Degradation of emerging contaminants in synthetic hydrolyzed urine by UV/peracetic acid: Free radical chemistry, and toxicity analysis

The ecological impact of emerging contaminants (ECs) in aquatic environments has raised concerns, particularly with regards to urine as a significant source of such contaminants in wastewater. The current investigation used the UV/Peracetic Acid (UV/PAA) processes, an innovative advanced oxidation technology, to effectively separate two emerging pollutants from urine at its source, namely, ciprofloxacin (CIP) and bisphenol A(BPA). The research findings demonstrate that the presence of the majority of characteristic ions has minimal impact on the degradation of ECs. However, in synthetic hydrolyzed urine, only NH4+ inhibits the degradation of two types of ECs, with a more pronounced effect observed on CIP degradation compared to BPA.The impact of halogen ions, specifically Cl− and I−, on the degradation of CIP in synthetic hydrolyzed urine was a complex phenomenon. When these two halogen ions are present individually, the generation of reactive halogen species (RHS) within the system enhances the degradation of CIP. However, when both types of ions coexist, the formation of diatomic radical species partially inhibits degradation. In terms of BPA degradation, while the production of reactive chlorine species (RCS) to some extent hinders the reaction rate, the generation of reactive iodine species (RIS) promotes the overall process. CIP undergoes fragmentation of the piperazine and quinoline rings, decarboxylation, defluorination reactions, as well as substitution reactions, leading to the formation of products with simplified structures. The degradation of BPA occurs gradually through hydroxyl and halogen substitution as well as isopropyl cleavage. The preliminary toxicity analysis confirmed that the presence of halogen ions in urine resulted in the formation of halogenated products in two types of ECs, albeit with an overall reduction in toxicity. The UV/PAA processes was considered to be an effective and relatively safe approach for the separation of ECs in urine.

Metabolic Profiling of Cochlear Organoids Identifies α-Ketoglutarate and NAD+ as Limiting Factors for Hair Cell Reprogramming.

Cochlear hair cells are the sensory cells responsible for transduction of acoustic signals. In mammals, damaged hair cells do not regenerate, resulting in permanent hearing loss. Reprogramming of the surrounding supporting cells to functional hair cells represent a novel strategy to hearing restoration. However, cellular processes governing the efficient and functional hair cell reprogramming are not completely understood. Employing the mouse cochlear organoid system, detailed metabolomic characterizations of the expanding and differentiating organoids are performed. It is found that hair cell differentiation is associated with increased mitochondrial electron transport chain (ETC) activity and reactive oxidative species generation. Transcriptome and metabolome analyses indicate reduced expression of oxidoreductases and tricyclic acid (TCA) cycle metabolites. The metabolic decoupling between ETC and TCA cycle limits the availability of the key metabolic cofactors, α-ketoglutarate (α-KG) and nicotinamide adenine dinucleotide (NAD+). Reduced expression of NAD+ in cochlear supporting cells by PGC1α deficiency further impairs hair cell reprogramming, while supplementation of α-KG and NAD+ promotes hair cell reprogramming both in vitro and in vivo. These findings reveal metabolic rewiring as a central cellular process during hair cell differentiation, and highlight the insufficiency of key metabolites as a metabolic barrier for efficient hair cell reprogramming.

Roles of soil minerals in the degradation of chlorpyrifos and its intermediate by microwave activated peroxymonosulfate

Soil mineral is one of the important factors that affecting oxidant decomposition and pollutants degradation in soil remediation. In this study, the effects of iron minerals, manganese minerals and clay minerals on the degradation of chlorpyrifos (CPF) and its intermediate product 3,5,6-trichloro-2-pyridinol (TCP) by microwave (MW) activated peroxymonosulfate (PMS) were investigated. As a result, the addition of minerals had slight inhibitory effect on the degradation efficiency of CPF by MW/PMS, but the degradation efficiency of TCP was improved by the addition of some specific minerals, including ferrihydrite, birnessite, and random symbiotic mineral of pyrolusite and ramsdellite (Pyr-Ram). The stronger MW absorption ability of minerals is beneficial for PMS decomposition, but the MW absorption ability of minerals cannot be fully utilized because of the weaker MW radiation intensity under constant temperature conditions. Through electron spin resonance test, quenching experiment and electrochemical experiment, electron transfer, SO4− and OH, SO4− dominated TCP degradation by MW/PMS with the addition of birnessite, Pyr-Ram and ferrihydrite, respectively. Besides, the adsorption effect of ferrihydrite also enhanced the removal of TCP. The redox of Mn (III)/Mn (IV) or Fe (II)/Fe (III) in manganese/iron minerals participated in the generation of reactive species. In addition, the addition of minerals not only increased the variety of alkyl hydroxylation products of CPF, causing different degradation pathways from CPF to TCP, but also further degraded TCP to dechlorination or hydroxylation products. This study demonstrated the synergistic effect of minerals and MW for PMS activation, provided new insights for the effects of soil properties on soil remediation by MW activated PMS technology.

Development of efficient nonthermal atmospheric-pressure Ar-plasma jet through simultaneous spectroscopic characterization and radical quantification

The work investigates the correlation between the plasma characteristics and reactive chemical species generation in an Ar-nonthermal atmospheric pressure plasma-jet (Ar-NTAPPJ) under various operating conditions such as gas flow rate, excitation voltage, and electrode gap and demonstrates the application of such understanding in developing efficient nonthermal plasma systems. The critical plasma parameters such as electron temperature (T e) and electron density (n e) under the various operating conditions were estimated using optical emission spectroscopy coupled with the collision radiative model and Stark broadening methods. At optimal setting of 5 LPM gas flow rate, 4 kV excitation voltage, and 6 mm electrode gap resulted in maximum T e (0.6 eV), enhancing •OH production (0.056 mM) in the liquid phase and OH(A-X) emission in the gas phase, highlighting the significance of operating conditions on building energy efficient plasma systems. The enhanced performance of the optimized Ar-NTAPPJ is demonstrated by taking atrazine as a model herbicide. The degradation performance data was correlated and validated with results obtained from spectroscopic diagnostics. By adequately tuning the operating parameters, four times enhancement in energy yield (∼150 mg kWh−1) was obtained without perturbing the nonthermal plasma mode. In nonthermal mode, to best of the authors knowledge, it is the highest reported energy yield for atrazine degradation. The scalability aspect of the present plasma jet was also investigated by Intensified Charge-Coupled Device camera-based imaging technique. The study establishes the importance of adequate diagnostics in developing efficient next-generation plasma reactors.