Reactive Species Research Articles

In silico estimation of polyethylene glycol coating effect on metallic NPs radio-sensitization in kilovoltage energy beams

PurposeNanoparticles (NPs) as radiosensitizers present a promising strategy for enhancing radiotherapy effectiveness, but their potential is significantly influenced by the properties of their surface coating, which can impact treatment outcomes. Most Monte Carlo studies have focused on metallic NPs without considering the impact of coating layers on radiosensitization. In this study, we aim to assess both the physical and radiobiological effects of nanoparticle coatings in nanoparticle-based radiation therapy.Materials and methodsIn this simulation study, we used Geant4 Monte Carlo (MC) toolkit (v10.07.p02) and simulated the bismuth, gold, iridium and gadolinium NPs coated with polyethylene glycol (PEG-400: Density: 1.13 g/cm³, Molar mass: 380–420 g/mol) as radiosensitizer for photon beams of 30, 60 and 100 keV. Secondary electron number and reactive oxygen species enhancement factor were estimated. Also, dose enhancement factor (DEF) was determined in spherical shells with logarithmic scale thickness from the nanoparticle surface to 4 mm.ResultsSecondary electron emission was highest at 30 keV for gold, bismuth, and iridium NPs, while gadolinium NPs peaked at 60 keV. Coating reduced electron emissions across all energies, with thicker coatings leading to a more significant decrease. DEF values declined with increasing radial distance from the NP surface and were lower with thicker coatings. For gadolinium NPs, DEF behavior differed due to K-edge energy effects. Reactive species generation varied, showing maximum production at 30 keV for gold, bismuth, and iridium NPs, while gadolinium NPs showed peak activity at 60 keV. PEG coatings enhanced reactive species formation at 100 keV.ConclusionThe findings indicate that the coating layer thickness and material not only influence the emission of secondary particles and DEF but also affect the generation of reactive species from water radiolysis. Specifically, thicker coatings reduce secondary particle emission and DEF, while PEG coatings demonstrate a dual behavior, offering both protective and enhancing effects depending on photon energy. These insights underscore the importance of optimizing NP design and coating in future studies to maximize therapeutic efficacy in nanoparticle-based radiation therapy.

Insight into the Efficient Selective Reduction of Cr(VI) in Sulfite/UV Process under Near-Neutral Conditions: The Critical Role of In Situ-Generated Sulfite Radical.

Efficient removal of contaminants in complex water matrices under mild conditions is highly desirable but still challenging. In this study, we unraveled the overlooked but crucial role of sulfite radical (SO3·-) in the efficient selective reduction of toxic Cr(VI) under near-neutral conditions. Fast removal of Cr(VI) at around pH 7 in sulfite/UV was found to be attributable to high reactivity of SO3·- toward HCrO4- (∼5.3 × 106 M-1 s-1). Furthermore, SO3·- was fast generated in situ via one-electron oxidation of S(IV) by transient reactive protonated Cr(V) and Cr(IV) intermediates. Therefore, the specific reactivity of SO3·- and its in situ generation together resulted in the surprisingly positive effect of nitrate and the efficient reduction of Cr(VI) in authentic surface water and industrial wastewater. A mathematical model was developed to simulate Cr(VI) removal in the process, and thus quantitatively demonstrated the roles of reactive species, i.e., SO3·- contributed to ∼93% of Cr(VI) reduction in surface water. Overall, this study provides an insight into the pivotal role of SO3·- in Cr(VI) reduction, and underscores its significance in selective reduction and detoxification of contaminants.

Effective periodate activation by the ball-milled bimetallic zero-valent iron/manganese oxides catalyst for sulfamethoxazole degradation

Developing a green and efficient catalyst for oxidant activation to tackle refractory organics pollution is challenging for water purification. In this study, we prepared a zero-valent iron-based bimetallic catalyst (ZVI/Mn3O4) for periodate (PI) activation using a simple and convenient ball-milling method. Electrochemical characterization and theoretical calculations confirm that the synergy between Fe and Mn enables the ZVI/Mn3O4 system to exhibit higher electron transfer efficiency compared to its individual components. Consequently, the ZVI/Mn3O4/PI system demonstrated enhanced PI activation and significantly improved removal of sulfamethoxazole (SMX), with reaction rates being 18.61 to 57.01 times higher than the comparison systems. The influence of various physicochemical parameters on SMX removal was investigated, confirming the wide tolerance ZVI/Mn3O4/PI system towards multiple aqueous matrices. Furthermore, the scalability of this system for industrial applications was validated through the preparation of larger batches of catalysts (4.21 g per batch) and testing in a custom-designed magnetic plate continuous-flow reactor. Quenching experiments and electron spin resonance tests confirmed that •O2– and 1O2 were the primary reactive species responsible for SMX degradation, with no toxic iodine byproducts detected, attributed to the carefully designed catalyst, which optimized the interaction between PI and the catalyst. Based on these findings, a potential catalytic mechanism and degradation pathway were proposed, highlighting ZVI's role as an electron pump to enhance Mn3O4's activation of PI. Additionally, toxicity assessments via prediction, zebrafish cultivation, wheat germination, and E. coli culture confirmed the excellent detoxification capability of ZVI/Mn3O4/PI system for SMX degradation. Overall, this work provides a new research paradigm for the convenient manufacture of ZVI-based catalysts and the development of advanced techniques for PI activation in water purification.

Rape straw biochar-assisted preparation of flower-like BiOCl with enriched oxygen vacancies for efficient photocatalytic CO2 reduction and pollutants degradation

Utilizing photocatalytic technology to transform CO2 into high added value chemical products has represented an effective strategy for alleviating the climate problems that have arisen due to excessive CO2 emissions. As a typical bismuth-based photocatalyst, BiOCl has garnered widespread attention due to its unique layered structure and low toxicity. However, the low light utilization efficiency and the rapid recombination of e−/h+ pairs severely hinder the practical application of BiOCl. Introducing oxygen vacancies (OVs) into BiOCl has been demonstrated to be one of the effective strategies for enhancing the photocatalytic performance of BiOCl. However, introduction of OVs through a mild and cost-effective approach remains a significant challenge. In this work, we developed a strategy for introducing OVs on BiOCl, which indues the growth of BiOCl into flower-like spherical structures and introduction of abundant OVs through addition of rape straw biochar (RC) under hydrothermal conditions. The synergistic interaction of RC and OVs endows with BiOCl more active sites as well as higher photogenerated carriers (e−/h+) separation efficiency. When the mass ratio of RC to BiOCl is 0.5 % (RC-0.5), the sample demonstrates the best performance, conversion of CO2 to CO on the sample is 4.0 μmol g−1 h−1, which is 3.08 times higher than that on the reference BiOCl. Additionally, versatility of the photocatalysts was further evaluated through photocatalytic degradation of rhodamine B (RhB) and perfluorooctanoic acid (PFOA). The degradation rate constant of RhB and PFOA on the RC-0.5 sample is 0.0642 min−1 and 0.00566 min−1, respectively, which is 2.26 times and 0.43 times higher than that on the reference BiOCl. Total organic carbon (TOC) experiments demonstrate that RhB can be effectively mineralized into CO2, H2O and small molecules on the photocatalyst. The main reactive species involved in the photocatalytic degradation process were investigated through active free radical trapping experiments and electron paramagnetic resonance (EPR). This work provides a viable strategy for the development of high-performance BiOCl photocatalysts for environmental applications.

Mechanism of β-MnO2 particle for the peroxymonosulfate activation under electric field: the promoting effect of carbamazepine on Mn(III) and reactive oxygen species production

In this study, β-MnO2 was introduced into electro-peroxymonosulfate process as particle electrodes (E/PMS/β-MnO2) to reveal the pathway of reactive manganese species (RMnS) and its promoting effect on reactive oxygen species (ROS) production. A significant synergistic was observed in the E/PMS/β-MnO2 process, the reaction constant was 3 times higher than that in the E/PMS process. The mechanism experiments revealed the generation pathway of Mn(III)aq during the E/PMS/β-MnO2 process. The pyrophosphate complex experiments and electrochemical analysis demonstrated that Mn(III)aq was dominantly generated through the electron transfer between carbamazepine (CBZ) and Mn(IV) under electric field conditions, rather than the reduction process in the cathode area. Furthermore, quenching experiments and competition kinetics method demonstrated the production of Mn(III)aq has the potential to enhance the formation of reactive oxygen species (ROS), especially •OH and SO4•−. In addition, Mn(V)aq and Mn(VI)aq was proved unable to be produced during the E/PMS/β-MnO2 process. Different from other similar electrochemical studies, 1O2 was mainly generated by the reaction betweenO2•− and •OH in this research. It was observed that the inclusion of Cl— facilitated the removal of CBZ, whereas the addition of humic acid (HA) had negligible impact on CBZ removal during the E/PMS/β-MnO2 process. At last, the results of various water matrices effects and toxicology analysis showed that the E/PMS/β-MnO2 process has satisfactory performance in practical application. This study could provide new insights for electro-persulfate treatment processes.

Sustainable photodegradation of tetracycline by surface-functionalized carbon nitride: Mechanism insight and toxicity assessment

Here, we report the facile preparation of amino- and vacancies-abundant carbon nitride photocatalyst using acetone as a low-boiling-point solvent and describe its successful performance of environmental purification. As a demonstration of the notion, tetracycline (TC) antibiotic as an emerging aqueous contaminant has been used as a model substrate for assessing the photoactivity of the modified carbon nitride and clarifying its intrinsic mechanism. 96 % of TC can be photocatalytically removed within 30 min, accompanied by a discernible mitigation in ecotoxicological impact. Reactive species, including •OH, •O2-, and photogenerated holes, are considered the critical oxidants. Meanwhile, the possible intermediates and transformation pathways of TC degradation were investigated utilizing the LC-MS technique, the Fukui function, and the T.E.S.T. software. The comprehensive approach furnishes valuable insights for assessing the evolutionary dynamics of tetracycline in an advanced oxidation process (AOP). This study offers a sustainable, cost-effective, and eco-friendly approach to preparing carbon nitride material, which is believed to open an avenue for the facile design of heterogeneous environmental photocatalysts and to provide insights into the various environmental applications.

The MICOS Complex Subunit Mic60 is Hijacked by Intracellular Bacteria to Manipulate Mitochondrial Dynamics and Promote Bacterial Pathogenicity.

Host mitochondria undergo fission and fusion, which bacteria often exploit for their infections. In this study, the underlying molecular mechanisms are aimed to clarify through which Listeria monocytogenes (L. monocytogenes), a human bacterial pathogen, manipulates mitochondrial dynamics to enhance its pathogenicity. It is demonstrated that L. monocytogenes triggers transient mitochondrial fission through its virulence factor listeriolysin O (LLO), driven by LLO's interaction with Mic60, a core component of the mitochondrial contact site and the cristae organizing system (MICOS). Specifically, Phe251 within LLO is identify as a crucial residue for binding to Mic60, crucial for LLO-induced mitochondrial fragmentation and bacterial pathogenicity. Importantly, it is that Mic60 affect the formation of F-actin tails recruited by L. monocytogenes, thereby contributing to intracellular bacterial infection. Mic60 plays a critical role in mediating changes in mitochondrial morphology, membrane potential, and reactive oxidative species (ROS) production, and L. monocytogenes infection exacerbates these changes by affecting Mic60 expression. These findings unveil a novel mechanism through which intracellular bacteria exploit host mitochondria, shedding light on the complex interplay between hosts and microbes during infections. This knowledge holds promise for developing innovative strategies to combat bacterial infections.

Unraveling Urban NOx Emission Sources in Polluted Arctic Wintertime Using NO2 Nitrogen Isotopes

AbstractNitrogen (N) isotopic fractionation during nitrogen oxides (NOx) cycling and conversion into atmospheric nitrate alters the original N isotopic composition (δ15N) of NOx emissions. Limited quantification of these isotopic effects in urban settings hampers the δ15N‐based identification and apportionment of NOx sources. δ15N of nitrogen dioxide (NO2) measured during winter in downtown Fairbanks, Alaska, displayed a large temporal variability, from −10.2 to 24.1‰. δ15N(NO2) records are found to be driven by equilibrium isotopic fractionation, at a rate in very close agreement with theoretical predictions. This result confirms that N isotopic partitioning between NO and NO2 can be accurately predicted over a wide range of conditions. This represents an important step for inferring NOx emission sources from isotopic composition measurement of reactive nitrogen species. After correcting our δ15N(NO2) measurements for N fractionation effects, a δ15N‐based source apportionment analysis identifies vehicle and space heating oil emissions as the dominant sources of breathing‐level NOx at this urban site. Despite their large NOx emissions, coal‐fired power plants with elevated chimney stacks (>26 m) appear to make a small contribution to surface NOx levels in downtown Fairbanks (likely less than 18% on average). The combined uncertainties of the δ15N of NOx from heating oil combustion and of the influence of low temperatures on the δ15N of NOx emitted by vehicle exhaust prevent a more detailed partitioning of surface NOx sources in Fairbanks.

Simultaneous Quantitation of Persulfides, Biothiols, and Hydrogen Sulfide through Sulfur Exchange Reaction with Trityl Spin Probes.

Reactive sulfur species (RSS) including persulfides (RSSHs), biothiols, and hydrogen sulfide (H2S) are key regulators in various physiological processes. To better understand the symbiotic relationship and interconversion of these RSS, it is highly desirable but challenging to develop analytical techniques that are capable of detecting and quantifying them. Herein, we report the rational design and synthesis of novel trityl-radical-based electron paramagnetic resonance (EPR) probes dubbed CT02-TNB and OX-TNB. CT02-TNB underwent fast sulfur exchange reactions with two reactive RSSHs (PS1 and PS2) which were released from their corresponding donors PSD1 and PSD2 to afford the specific conjugates. The resulting conjugates exhibit characteristic EPR spectra, thus enabling discriminative detection and quantitation of the two RSSHs. Moreover, CT02-TNB showed good response toward other RSS including glutathione (GSH), cysteine (Cys), H2S, and sulfite as well. Importantly, based on the updated EPR spectral simulation program, simultaneous quantitation of multiple RSS (e.g., PS1/GSH/Cys or PS1/GSH/H2S) by CT02-TNB was also achieved. Finally, the levels of released PS1 from PSD1 and endogenous GSH in isolated mouse livers were measured by the hydrophilic OX-TNB. This work represents the first study achieving discriminative and quantitative detection of different persulfides and other RSS by a spectroscopic method.

O6-Alkylguanine-DNA Alkyltransferase Maintains Genome Integrity by Forming DNA-Protein Cross-Links during Inflammation-Associated Peroxynitrite-Mediated DNA Damage.

Inflammation is an early immune response against invading pathogens and damaged tissue. Although beneficial, uncontrolled inflammation leads to various diseases including cancer in a chronic setting. Peroxynitrite (PN) is a major reactive nitrogen species generated during inflammation. It produces various DNA lesions including 8-nitro-guanine which spontaneously converts into abasic sites, resulting in DNA strand breakage, and is suspected to be mutagenic. Here, we report the discovery of a previously unrecognized function of the human repair protein O6-alkylguanine-DNA alkyltransferase (hAGT or MGMT). We showed that hAGT through its active site nucleophilic Cys145 thiolate spontaneously reacts with 8-nitro-guanine in DNA to form a stable DNA-protein cross-link (DPC). Interestingly, the process of DPC formation provided protection from PN-mediated genome instability, growth arrest, and apoptosis. The Cys145 mutant of hAGT failed to form a DPC and was unable to protect cells from inflammation-associated PN-mediated cytotoxicity. Gel-shift, dot blot, and UV-vis assays showed formation of a covalent linkage between PN-damaged DNA and hAGT through its active site Cys145. Finally, expression of hAGT was found to be significantly increased by induced macrophages and PN. The data presented here clearly demonstrated hAGT as a dual-function protein that along with DNA repair is capable of maintaining genomic integrity and providing protection from the toxicity caused by PN-mediated DNA damage. Although DPCs are known to be detrimental to the cell, recently, multiple pathways have been identified in normal cells for their repair.

Evaluating the Effect of Argon and Helium Atmospheric Cold Plasma Jets on Wound Healing in Rats: A Comparative Histopathological and Biochemical Analysis

Background: Cold atmospheric plasma (CAP) has emerged as a promising therapy for wound healing to deliver controlled doses of reactive species to tissues. Argon and helium, as gases used in CAP, are noted for their unique properties and therapeutic potential. Objectives: This study compared the effects of argon and helium atmospheric cold plasma jets on wound healing in a rat model, assessing histopathological changes and biochemical parameters. Methods: This randomized, controlled experimental study involved 18 male Wistar rats randomly assigned to control, helium-treated, and argon-treated groups. Wounds were created between the shoulders under anesthesia, treated with respective plasmas, and monitored for healing progress through macroscopic and microscopic evaluations. Results: Hemoglobin (HGB) and hematocrit (HCT) levels were significantly higher in experimental groups compared to controls (P < 0.05), while mean corpuscular volume (MCV) was lower (P < 0.05). Tumor necrosis factor alpha (TNF-α) levels were highest in helium-treated and lowest in argon-treated rats (P < 0.05). Argon-treated rats showed enhanced IL-6, hyperemia, angiogenesis, and re-epithelialization, with lower TNF-α and necrotic layer thickness than other groups (P < 0.05). Conclusions: Both argon and helium atmospheric cold plasma jets enhanced wound healing in rat models, demonstrating superior efficacy in promoting angiogenesis and re-epithelialization processes.

Development of chitosan-acrylic acid based hydrogels with incorporated polyaniline and plasma treatment

Hybrid hydrogels are materials that incorporate features from multicomponent systems of polymers, significantly improving their functionality and making them ideal for biomedical applications. Both natural and synthetic polymers are utilized, further enhancing their functionality. The combination of polyaniline (PANI), chitosan (CS), and acrylic acid (AA) can result in a multifunctional hybrid hydrogel that is antibacterial, hydrophilic, and salt-sensitive. A multifunctional PANI-CS-AA with varying PANI weight ratio was synthesized in this study. In addition, improving the surface of the multifunctional hydrogels by atmospheric pressure plasma (APP) treatment was also investigated. During APP treatment, the production of reactive species (e.g., OH and N2 radicals) responsible for the functionalization of the hydrogel surface was confirmed through optical emission spectroscopy. The integration of three polymer components in the synthesized hydrogels was confirmed through the presence of their mid-FTIR spectral characteristics, particularly in the AA and CS C=O, PANI quinonoid and benzenoid units, AA COO−, and the PANI aromatic and C—H vibration regions. Moreover, the hybrid hydrogels with incorporated PANI and APP treatment improved their wettability and surface free energy (SFE) characteristics. The hybrid hydrogels with 0.25 wt. % PANI and exposed to 2 min air plasma yielded the highest hydrophilicity and total SFE with values 41.27° ± 2.15° and 135.68 ± 4.72 mJ/m2, respectively. The plasma-treated 0.25PANI-2.5CS-4AA samples exhibit improved swelling response in water (Smax = 1310 ± 100; ks = 0.005) and saline media (Smax = 1280 ± 80; ks = 0.001) due to enhanced polymeric chains and affinity toward polar liquids. Synthesized hydrogels exhibited antibacterial activity, as evidenced by the zone of inhibition test. Clearing zones measured were in the range of 16–27 mm. The study developed an APP-treated tricomponent hydrogel consisting of PANI, CS, and AA that has improved hydrophilicity, salt sensitivity, and antibacterial features.

Iron–Cobalt Bimetallic Metal–Organic Framework-Derived Carbon Materials Activate PMS to Degrade Tetracycline Hydrochloride in Water

Organic pollutants entering water bodies lead to severe water pollution, posing a threat to human health. The activation of persulfate advanced oxidation processes using carbon materials derived from MOFs as substrates can efficiently treat wastewater contaminated with organic pollutants. This research uses NH2-MIL-101(Fe) as a substrate, doped with Fe2+ and Co2+, to prepare Fe/Co-CNs through a one-step carbonization method. The surface morphology, pore structure, and chemical composition of Fe/Co-CNs were investigated using characterization techniques such as XRD, SEM, TEM, XPS, FT-IR, BET, and Raman. A comparative study was conducted on the performance of catalysts with different Fe/Co ratios in activating PMS for the degradation of organic pollutants, as well as the effects of various influencing factors (the dosage of Fe/Co-CNs, the amount of peroxymonosulfate (PMS), the initial pH of the solution, the TC concentration, and inorganic anions) on the catalyst’s activation of persulfate for TC degradation. Through radical quenching experiments and post-degradation XPS analysis, the active radicals in the FeCo-CNs/PMS system were investigated to explain the possible mechanism of TC degradation in the Fe/Co-CNs/PMS system. The results indicate that Fe/Co-CNs-2 (with a Co2+ doping amount of 20%) achieves a degradation rate of 93.34% for TC (tetracycline hydrochloride) within 30 min when activating PMS, outperforming other Co2+ doping amounts. In addition, singlet oxygen (1O2) is the main reactive species in the reaction system.

Recent Insights Into Interfacial Transport and Chemical Reactions of Plasma‐Generated Species in Liquid

ABSTRACTThe chemistry of plasma–liquid interactions involves a complex interplay of physical and chemical processes at the plasma–liquid interface. These interactions give rise to the generation, transport, and transformation of various reactive species. Since the publication of the Lorenz Roadmap in 2016, significant progress has been made in understanding the interfacial transport and coupled reactions of plasma‐generated species with inorganic and organic compounds. However, critical aspects of plasma–liquid chemistry and mass transfer still require further investigation. This review summarizes recent work on processes at the plasma–liquid interface and the coupled reactions in the liquid phase. We highlight key findings related to the involvement of O atoms, H radicals, solvated electrons, photons, and nitrogen‐derived species at the interface and within the bulk liquid.

The Interplay of Nitric Oxide and Nitrosative Modifications in Maize: Implications for Aphid Herbivory and Drought Stress.

Nitric oxide (NO) and other reactive nitrogen species (RNS) are considered to be signaling molecules in higher plants involved in the regulation of growth and development processes. However, the molecular mechanisms of their formation, removal, and participation in plant responses to adverse environmental stimuli remain largely unclear. Therefore, the aim of this study was to assess the influence of selected single stresses and combined stresses (i.e., Rhopalosiphum padi L. aphid infestation, drought, aphid infestation, and drought) and post-stress recovery on the contents of NO and peroxynitrite anion (ONOO-), as well as the levels of mRNA and protein nitration (i.e., the 8-nitroguanine and protein 3-nitrotyrosine amounts, respectively), in maize seedlings (Zea mays L.). Moreover, the expression patterns of the two tested genes (nos-ip, encoding nitric oxide synthase-interacting protein, and nr1, encoding nitrate reductase 1) involved in NO metabolism in maize plants were quantified. We identified significant intervarietal, time-course, and stress-dependent differences in the levels of the quantified parameters. Under the investigated stress conditions, the aphid-resistant Waza cv. seedlings were characterized by a higher and earlier NO accumulation and mRNA nitration level and an increased expression of the two target genes (nos-ip and nr1), compared to the aphid-susceptible Złota Karłowa cv. seedlings. Conversely, the Złota Karłowa plants responded with a greater elevation in the content of ONOO- and protein 3-nitrotyrosine than the Waza cv. plants The multifaceted role of NO and its derivatives in maize plants challenged by single and combined stresses, as well as during post-stress recovery, is discussed.

Overturned doping inert Ce into mesoporous CuO for enhanced peroxydisulfate activation and bisphenols degradation

Transition metal oxides have been recently investigated as excellent catalyst for peroxydisulfate (PDS) activation, but suffers from slow redox cycle of metal species. In this work, a novel avenue for facilitating valence cycles of Cu2+/Cu+ was proposed by overturned doping inert Ce into mesoporous CuO. Increased formation of active sites (Cu-Ce interface) and oxygen vacancy was achieved, resulting in accelerated interfacial electron transfer and facilitated valence cycles of Cu2+/Cu+. The Ce-doped mesoporous CuO (CeCuOx) exhibited greatly enhanced activity toward PDS activation and efficient removal of different bisphenols in a wide pH working range. The degradation of bisphenols followed a nonradical oxidation pathway based on electron transfer process (ETP), and CeCuOx@PDS complex was proved to be the primary reactive species. The CeCuOx/PDS system exhibited good stability and superior catalytic performance in complicated water matrix, and would be a promising catalyst for wastewater purification. This work provides a new prospect for boosting the redox behavior of metal active sites for environmental remediation.

Photocatalytic degradation of ampicillin antibiotics in aqueous solution utilizing ZnFe2O4/MWCNTs/TiO2 ternary nanocomposite under solar light irradiation

In this study, a novel photocatalyst composed of zinc ferrite (ZnFe₂O₄), titanium dioxide (TiO₂), and multi-walled carbon nanotubes (MWCNTs) was successfully synthesized via the hydrothermal method, and evaluated for the degradation of ampicillin (AMP) in aqueous solutions. The synthesized nanocomposites were thoroughly characterized using various analytical techniques, including XRD, HR-SEM, HR-TEM, EDX, UV-Vis, FT-IR, BET, and XPS analysis. Crystallite sizes of 24.18 nm for ZnFe₂O₄ and 17.8 nm for TiO₂ were determined. The composite exhibited a band gap of 1.4 eV, indicating its enhanced photocatalytic activity. The photocatalytic performance was assessed under varying conditions, including different nanocomposite dosages (0.3–1 g/L), AMP concentrations (10–50 mg/L), and pH values (2–12). The optimal AMP degradation efficiency of 99.2 % was achieved using 0.7 g/L of the photocatalyst, 10 mg/L of AMP, and a pH of 12 under 90 min of solar irradiation. These optimal parameters were then applied to evaluate AMP degradation using ZnFe2O4, TiO2, and ZnFe2O4/MWCNTs individually, with the degradation rate analyzed using a pseudo-first-order model. The superior photocatalytic efficiency can be primarily attributed to improved charge transfer dynamics and effective electron-hole separation, enabled by the doping of MWCNTs. Hydroxyl radicals (OH•) were identified as the primary reactive species responsible for AMP degradation. Furthermore, the catalyst retained 91 % of its photocatalytic efficiency after eight consecutive cycles, demonstrating excellent stability and reusability. These results underscore the potential of the ZnFe₂O₄/MWCNTs/TiO₂ composite as a highly effective and sustainable photocatalyst for removing pharmaceutical pollutants from aquatic environments.

A comprehensive review of sensors of radiation-induced damage, radiation-induced proximal events, and cell death.

Radiation, a universal component of Earth's environment, is categorized into non-ionizing and ionizing forms. While non-ionizing radiation is relatively harmless, ionizing radiation possesses sufficient energy to ionize atoms and disrupt DNA, leading to cell damage, mutation, cancer, and cell death. The extensive use of radionuclides and ionizing radiation in nuclear technology and medical applications has sparked global concern for their capacity to cause acute and chronic illnesses. Ionizing radiation induces DNA damage either directly through strand breaks and base change or indirectly by generating reactive oxygen species (ROS) and reactive nitrogen species (RNS) via radiolysis of water. This damage triggers a complex cellular response involving recognition of DNA damage, cell cycle arrest, DNA repair mechanisms, release of pro-inflammatory cytokines, and cell death. This review focuses on the mechanisms of radiation-induced cellular damage, recognition of DNA damage and subsequent activation of repair processes, and the critical role of the innate immune response in resolution of the injury. Emphasis is placed on pattern recognition receptors (PRRs) and related receptors that detect damage-associated molecular patterns (DAMPs) and initiate downstream signaling pathways. Radiation-induced cell death pathways are discussed in detail. Understanding these processes is crucial for developing strategies to mitigate the harmful effects of radiation and improve therapeutic outcomes.

A highly permeable nanoplatform based on functionalized carbon dots for synergistic reactive oxygen/nitrogen species tumor therapy

Reactive oxygen species (ROS)-based antitumor strategies, particularly chemodynamic therapy, have garnered considerable attention. However, challenges such as difficulties in achieving deep penetration, relatively low H2O2 levels in the tumor microenvironment, the requirement for low pH by the Fenton reaction, and their short lifespan have impeded satisfactory therapeutic outcomes. Hence, we have developed a nanoplatform with enhanced permeability that not only generates significant amounts of ROS but also converts them into longer-lasting reactive nitrogen species (RNS), thereby improving tumor therapy efficacy. In our study, carbon dots were functionalized by doping with gold atoms and grafting nitrosoglutathione (GSNO) to form ACN, which exhibits glucose oxidase-like properties and enables laser-responsive NO release. ACN and indocyanine green (ICG) were then loaded onto MnO2 nanoflowers to form MnO2@AI. Upon arrival at the tumor site, MnO2 reacts with H2O2 and GSH, leading to its degradation and the subsequent release of ACN, which is characterized by three permeation-promoting properties: ultra-small size, positive charge, and NO content. In addition, ACN promotes H2O2 production through glucose metabolism and reduces pH, both of which enhance the Fenton-like reaction of MnO2, thereby amplifying ROS generation. The ICG in MnO2@AI enhances its photothermal properties, leading to the responsive release of NO from GSNO grafted onto ACN, which then reacts with the increased ROS to generate more toxic RNS. Collectively, the approach described herein offers substantial potential for advancing the treatment of malignant tumors.

Enhancing the degradation of microplastics through combined KMnO4 oxidation and UV radiation

The pervasive issue of microplastics in aquatic environments presents a formidable challenge to traditional water treatment methodologies, including those utilizing KMnO4. This study pioneers advanced oxidation processes (AOPs) method aimed at improving the degradation of PE microplastics by employing a dual treatment strategy that combines KMnO4 oxidation with UV irradiation. Detailed analysis of the surface modifications and chemical functional groups of the treated PE microplastics revealed the establishment of Mn-O-Mn linkages on their surfaces. Weight reductions of 3.9%, 4.9%, and 7.5% were observed for the KMnO4/UVA, KMnO4/UVB, and KMnO4/UVC treatments over seven days, respectively. The emergence of carboxyl and hydroxyl groups played a crucial role in accelerating the degradation process. Notably, the combined application of UVC rays and KMnO4 resulted in the most effective degradation of PE microplastics observed in our study. The process significantly enhanced the formation of MnO2 particles from KMnO4 oxidation, with concentrations ranging from 0.036 to 0.070 mM for KMnO4/UVA, 0.066–0.097 mM for KMnO4/UVB, and 0.086–0.180 mM for KMnO4/UVC. Furthermore, the influence of varying pH levels, KMnO4 concentrations, and different water sources on the degradation efficacy was investigated. The pivotal role of free radicals and reactive manganese species in promoting the degradation of PE microplastics was identified. A comparative evaluation with treatments solely utilizing KMnO4 or UV light highlighted the enhanced effectiveness of the combined approach, demonstrating its potential as an efficient solution for reducing microplastic contamination in aquatic systems.