Stability Of Matrices Research Articles

Determination of cefuroxime in human blood and urine using UHPLC-MS/MS and its application to stability study of cefuroxime over 278 days

Purpose: Forensically, the widespread use of antibiotics necessitates methods for their detection in biological materials to ascertain their role in adverse reactions or fatalities. Given the need to conduct toxicological studies on materials stored for extended periods under various temperature conditions, research on antibiotic stability in biological matrices over such durations is crucial for accurate toxicological assessments. Methods: The stability of cefuroxime in blood and urine was determined for 278 days at three different temperatures: -15°C, +4°C, +23°C. The analyses were conducted using ultra-high-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry. Results: The method met all validation requirements. This study also describes the results of the thermal stability of cefuroxime. Cefuroxime showed the greatest stability at -15°C and was highly unstable at room temperature (+23°C) in all types of studied biological matrices. Conclusions: The study confirms instability of cefuroxime in blood and urine samples. Therefore, the analysis of this antibiotic in biological matrices for purposes such as forensic toxicology should be performed as soon as possible after sampling to avoid decline in concentration. In cases of prolonged material storage, the concentrations should be cautiously interpreted in the prepared expertise.

Effect of Various Carbohydrates in Aqueous Solutions on Color Stability and Degradation Kinetics of Selected Anthocyanins During Storage.

Anthocyanins are flavonoid substances of plant origin with potential antioxidant effects. Because of their intense colors, they are used as natural dyes in food. However, their stability in food matrices is limited. This study aimed to verify the effect of selected carbohydrates on the stability of anthocyanins (cyanidin-3-O-β-glucopyranoside, cyanidin-3-O-β-galactopyranoside, cyanidin-3-O-β-rutinoside and delphinidin-3-O-β-rutinoside) during the accelerated storage test, since carbohydrates help to preserve the typical color of anthocyanins, increase their shelf-life and availability in the organism, and reduce losses during processing. Moreover, the kinetic parameters of anthocyanin degradation (Ea, k, t1/2) were determined. Sucrose was found to have the greatest potential for retarding anthocyanin degradation during storage, whereas fructose exerted an accelerating effect. Glycosidation of anthocyanin aglycone had no significant effect in terms of their stability. Anthocyanin degradation was significantly positively correlated with the change in the a* parameter (redness), and subsequently, a significant positive correlation was observed in the determination of the kinetic parameters for anthocyanins and the a* parameter. The highest stability of anthocyanins was observed in the presence of sucrose and their degradation can be predicted by the value of the a* parameter, which would also be a very fast and non-destructive method for food processing companies.

A Closed-Form Solution to Observer Design Problem for Ostensible Metzler Takagi-Sugeno Systems

This paper addresses the state estimation problems related to the generalized fuzzy observer design for ostensible Metzler Takagi-Sugeno (T-S) systems. Attention is focused on design constraints for the concept of diagonal stabilization and positivity of observer gain matrices. On the basis of some new interpretations, the parameterizations of ostensible Metzler T-S fuzzy systems is presented, which opens the way to the solution of the design problem using only the principle of linear matrix inequalities. The same approach is intended to ensure the stability of the dynamics of the estimation error. The presented method extends and generalizes the results that have been presented in the literature so far.

Toxicokinetic Profiles and Potential Endocrine Disruption Effects at the Reproductive Level Promoted by Siloxanes Used in Consumer Products.

Siloxanes, commonly known as silicones, are polymeric compounds made up of silicon and oxygen atoms bonded together alternately. Within this group of substances are linear methyl-siloxanes and cyclic methyl-siloxanes, with octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) being the most produced and used industrially. Due to their versatility, high production volume, stability, and local presence in environmental matrices and biological fluids such as breast milk, fat, and plasma, siloxanes have been considered persistent organic pollutants, representing a public health problem. This represents a public health concern, especially when different investigations have reported potential endocrine effects at the reproductive level in experimental animals exposed to D4 and D5. The objective of this study was to review the potential reproductive and endocrine effects derived from siloxanes present in personal care products (PCPs). The results of the literature review confirmed that D4 and D5 were the most used siloxanes as additives in PCP because they improve the emollient properties of the cosmetic and the physical appearance of hair and skin. Similarly the toxicological effects of siloxanes, particularly D4, D5, and D6 included significant endocrine disruption, reproductive toxicity, and liver toxicity. Studies in SD and F-344 rats, commonly used to assess these effects, have shown that D4 has low estrogenic activity, binding to ER-α receptors, whereas D5 does not bind to estrogen receptors. D4 exposure has been associated with increased uterine weight and estrous cycle alterations, leading to prolonged exposure to estrogens, which raises the risk of endometrial hyperproliferation and carcinogenesis. Recent research highlights that D5 exposure disrupts follicle growth, endometrial receptivity, and steroidogenesis, resulting in infertility and hormonal imbalances, potentially causing disorders like endometriosis and increased cancer risk. Chronic exposure to D5 has been linked to the development of uterine endometrial adenocarcinoma, with higher doses further elevating this risk.

A validated LC-MS/MS method for the simultaneous quantification of iothalamate and hippuran in serum and urine for non-radioactive kidney function assessment

A novel liquid chromatography-tandem mass spectrometry method is described for the quantitative determination of the kidney function markers iothalamate and hippuran in human serum and urine. It is based on protein precipitation with methanol followed by dilution of the supernatant for serum and simple dilution for urine. The polar analytes are chromatographically separated by a 6.5-min gradient on a low-ligand density reversed-phase column; detection is performed by electrospray ionization tandem mass spectrometry in the positive ion mode against stable-isotope labeled internal standards.The results of a thorough method validation show that iothalamate and hippuran can be simultaneously quantified in the concentration ranges 0.500–30.0 ng/mL and 10.0–5000 ng/mL for serum and urine, respectively, with values for CV and absolute bias not exceeding 10 %, and with sufficient stability in all relevant matrices and solvents. The method was successfully applied for the analysis of serum and urine samples of multiple individuals who received both iothalamate and hippuran.

Biosynthesis of mechanically recyclable 3D-Cu2O@megacatalyst for Fenton-like catalysis of tetracycline and the mechanistic insights

Treating sewage waters contaminated with persistent organic pollutants (POPs) presents a pressing environmental concern, mandating, affordable, implementable and sustainable remediations. Supported catalysts, wherein metal nanoparticles are grafted onto inert supports to endow porosity, reactant access, performance and catalyst re-use are emerging as sustainable catalytic platforms. Herein, size-controllable, mechanically recyclable 3D-Cu2O@megacatalyst of ∼81 ± 5 cm2, ∼37 ± 3 cm2 and ∼1 ± 0.6 cm2 were biofabricated by exploiting the innate metal binding feature of pristine eggshells. The as-fabricated Cu2O@megacatalyst was utilized for the Fenton-like treatment of POPs, with exceptional activities against diverse molecules: antibiotic (tetracycline (TC)), textile dye (methylene blue) and pharmaceutical precursor (4-nitrophenol) with the degradation efficiencies of 95.6 %, 96.8 % and 93.4 %, respectively. Optimization studies revealed that our megacatalyst can function consistently in the presence of various oxidising agents, free radical scavengers, wide pH, temperatures and inorganic and organic contaminants. The catalyst demonstrated stability and catalytic efficiency in different real-time water matrices: ultrapure water-95.6 %, tap water-84 %, lake water-86 %, and river water-91 %. Furthermore, plausible reaction mechanism and decomposition pathways for TC degradation were assessed using GC-MS, while evaluating the toxicity using ECOSAR and oxygen uptake assay, which revealed less toxic reaction intermediates and end products. Overall, our results provide new insight into the sustainable development of a generalized highly stable, scalable, ultra-efficient and mechanically recyclable Fenton-like supported catalyst for the detoxification of POPs in sewage waters.

Carbon metabolism mechanisms and evolution characteristics analysis of the food-water-energy nexus system under blue-green infrastructure changes

Food, water, and energy comprise a complex system (FWE nexus) that generates much carbon emissions during operation. At the same time, urban blue-green infrastructure (BGI) has a critical carbon sequestration function. This paper combines the functions of the FWE nexus and BGI and uses ecological network analysis (ENA) and the Markov model to measure the carbon metabolism (CM) mechanisms and evolutionary characteristics of BGI and FWE nexus (BGI-FWE nexus) complex systems. The results show that Guangzhou has high carbon emissions, and Zhaoqing and Huizhou have high carbon sequestration. Resident land and industrial and transportation land transfers to different land uses are more likely to produce positive carbon flows, while BGI transfers to other types are more likely to produce negative carbon flows. The study of CM mechanisms reveals a high proportion of competition relationships and a low proportion of mutualism relationships. The ecological utility index (EUI) tends to fall initially and then increase, peaking at 0.84 in 2015–2020, the highest value for the study period. The CM network has less system robustness (SR) and is in an unsustainable state of high redundancy and low efficiency. The mechanism evolution characterization study’s findings show a decreased likelihood of remaining original and less stability in the spatial transfer probability matrices of EUI and SR. In this study, we constructed a BGI-FWE nexus research framework based on the different CM functions of BGI and FWE nexus. The research framework contributes to the realization of carbon reduction in the FWE nexus system and is essential for the planning and management of urban BGI.

Effects of Sequential Induction Combining Thermal Treatment with Ultrasound or High Hydrostatic Pressure on the Physicochemical and Mechanical Properties of Pea Protein-Psyllium Hydrogels as Elderberry Extract Carriers.

Entrapping bioactive ingredients like elderberry extract in hydrogels improves their stability and functionality in food matrices. This study assessed the effect of sequential thermal treatment with ultrasound (US) or high hydrostatic pressure (HHP) and treatment duration on pea protein-psyllium hydrogels as elderberry extract carriers. Measurements included color parameters, extract entrapment efficiency, physical stability, textural properties, microrheology, FT-IR, thermal degradation (TGA), SEM images, total polyphenols content, antioxidant activity, and reducing power. The control hydrogel was obtained using only thermal induction. Both treatments impacted physical stability by affecting biopolymer aggregate structures. Thermal and US combined induction resulted in hydrogels with noticeable color changes and reduced entrapment efficiency. Conversely, thermal and HHP-combined induction, especially with extended secondary treatment (10 min), enhanced hydrogel strength, uniformity, and extract entrapment efficiency (EE = 33% for P10). FT-IR and TGA indicated no chemical structural alterations post-treatment. Sequential thermal and HHP induction preserved polyphenol content, antioxidant activity (ABTS = 5.8 mg TE/g d.m.; DPPH = 11.1 mg TE/g d.m.), and reducing power (RP = 1.08 mg TE/g d.m.) due to the dense hydrogel structure effectively enclosing the elderberry extract. Sequential thermal and HHP induction was more effective in developing pea protein-psyllium hydrogels for elderberry extract entrapment.

Coordination-Driven Nanomedicine Mitigates One-Lung Ventilation-Induced Lung Injury via Radicals Scavenging and Cell Pyroptosis Inhibition.

One-lung ventilation (OLV) during thoracic surgery often leads to post-operative complications, yet effective pharmacological interventions are lacking. This study reports a baicalin-based metal-coordination nanomedicine with disulfiram (DSF) co-loading to address one-lung ventilation-induced lung injury and reperfusion injury (OLV-LIRI). Baicalin, known for its robust antioxidant properties, suffers from poor water solubility and stability. Leveraging nanotechnology, baicalin's coordination is systematically explored with seven common metal ions, designing iron/copper-mediated binary coordination nanoparticles to overcome these limitations. The self-assembled nanoparticles, primarily formed through metal coordination and π-π stacking forces, encapsulated DSF, ensuring high colloidal stability in diverse physiological matrices. Upon a single-dose administration via endotracheal intubation, the nanoparticles efficiently accumulate in lung tissues and swiftly penetrate the pulmonary mucosa. Intracellularly, baicalin exhibits free radical scavenging activity to suppress inflammation. Concurrently, the release of Cu2+ and DSF enables the in situ generation of CuET, a potent inhibitor of cell pyroptosis. Harnessing these multifaceted mechanisms, the nanoparticles alleviate lung injury symptoms without notable toxic side effects, suggesting a promising preventive strategy for OLV-LIRI.

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.

Unveiling the Potential of Spirulina Biomass—A Glimpse into the Future Circular Economy Using Green and Blue Ingredients

The present work aims to explore Spirulina biomass’ functional and technological marvels and its components, such as C-phycocyanin (C-PC), in modern food systems from a circular economy perspective, evaluating a decade of insights and innovations. This comprehensive review delves into the pivotal studies of the past decade, spotlighting the vital importance of maintaining stability in various food matrices to unleash the full biological impacts. Through the lens of food science intertwined with circular economy principles, this analysis meets health and environmental requisites and explores the harmonious synergy between food systems, economy, and industry. While Spirulina has typically served as a supplement, its untapped potential as a fundamental food ingredient has been unveiled, showcasing its abundant nutritional and functional attributes. Technological hurdles in preserving the vibrant color of C-PC have been triumphantly surmounted through simple temperature control methods or cutting-edge nanotechnology applications. Despite the gap in sensory acceptance studies, the emergence of blue foods introduces groundbreaking functional and innovative avenues for the food industry.

Simultaneous TG―FTIR studies show high thermal resilience in core organic matrix of molluscan gastropod shell of N. josephinia

Nacre—a biological composite of alternating layers of aragonite platelets and organic matrices, derived from biomaterials like molluscan shells has recently attracted a lot of interest as a potential substitute for ceramic material in orthopedic tissue engineering. It is formed as a result of interesting biomineralization processes. Molluscs use a striking variety of structural motifs to build their shells composed of calcium carbonate and a small percentage of proteins. These integral proteins determine the structural organization and properties of the mineralized composite. However, the composition and thermal stability of these proteinous matrices remains a mystery. Until now it was presumed that the organic matrix in a shell degrades completely up to 500 °C (stage―I). Stage―II comprises degradation of CaCO3 to CaO spanning about 600 °C to 850 °C. However, in case of a gastropod mollusc shell of Neverita josephinia, stage―III was also observed, in which majority weight loss of core organic proteinous matrix (OPM) exceeding 6 wt%, starts after about 1000 °C of thermal heating. It is observed that the core organic matrix (OM) has varied composition throughout the shell, stronger bonding, complex topology and has very high thermal resilience even up to 1400 °C. Simultaneous analysis of evolved gases by FTIR spectrometer coupled with thermogravimetric analyzer shows the composition of non-mineral species is more than 8 wt%. The results are supported by room temperature as well as gas phase by FTIR spectroscopy, XRD, SEM, CHNS analyses. The XRD spectra of the pristine shell powder and that calcined at 550 °C reveal aragonite to calcite phase transformation in calcium carbonate. The SEM shows the cross-lamellar morphology of the gastropod mollusk shell. There are two different sets of organic matrices: one with complex topology and a very tight binding to the mineral components (intra-crystalline), and the other with a loose binding to the mineral (inter-platelet area). Elemental analysis (CHNS) data, also supports this. This study identifies that the organic matrix, comprising proteins, peptides, lipids, and carbohydrates, exhibits complex topology and strong mineral bonding, contributing to the shell's notable mechanical strength and resistance to thermal degradation. The implications of this high thermal resilience for the shell's mechanical properties and potential biomineralization processes are discussed, suggesting a reevaluation of the organic matrix's role in molluscan shells.

0D/1D CuO-Cu2O/ZnO p-n heterojunction with high photocatalytic activity for the degradation of dyes and Naproxen

The development of highly active photocatalysts with broad spectrum response is of paramount importance for photocatalytic applications. Herein, heterostructured CuO-Cu2O/ZnO photocatalysts were prepared in a single step and under mild conditions using a photodeposition process which allows to deposit CuO-Cu2O particles with an average size of ca. 2.4 nm on the surface of ZnO nanorods. The p-n heterojunction built between CuO-Cu2O and ZnO allows to increase both the visible light response of the photocatalyst and the charge separation. The CuO-Cu2O(10%)/ZnO catalyst exhibits the highest activity for the degradation of dyes (Rhodamine B and Remazol Brilliant Blue R) and of Naproxen under simulated solar light irradiation. Based on scavenging experiments, holes, superoxide radicals O2●- and singlet oxygen 1O2 are the dominant species involved in the photocatalytic degradation and a mechanism is proposed. Due to its high stability and photocatalytic performance in various water matrices, the CuO-Cu2O(10%)/ZnO nanohybrid is of high potential for the large scale remediation of organic pollutants in wastewater.

Human cardiac troponin complex stability in various matrices

Human cardiac troponin complex stability in various matrices

Recent Advances in Aptamer-Based Biosensors for Bacterial Detection.

The rapid and sensitive detection of pathogenic bacteria is becoming increasingly important for the timely prevention of contamination and the treatment of infections. Biosensors based on nucleic acid aptamers, integrated with optical, electrochemical, and mass-sensitive analytical techniques, have garnered intense interest because of their versatility, cost-efficiency, and ability to exhibit high affinity and specificity in binding bacterial biomarkers, toxins, and whole cells. This review highlights the development of aptamers, their structural characterization, and the chemical modifications enabling optimized recognition properties and enhanced stability in complex biological matrices. Furthermore, recent examples of aptasensors for the detection of bacterial cells, biomarkers, and toxins are discussed. Finally, we explore the barriers to and discuss perspectives on the application of aptamer-based bacterial detection.

Antimicrobial Efficacy of a Vegetable Oil Plasticizer in PVC Matrices.

The growing prevalence of bacterial and viral infections, highlighted by the recent COVID-19 pandemic, urgently calls for new antimicrobial strategies. To this end, we have synthesized and characterized a novel fatty acid epoxy-ester plasticizer for polymers, named GDE. GDE is not only sustainable and user-friendly but also demonstrates superior plasticizing properties, while its epoxy components improve the heat stability of PVC-based matrices. A key feature of GDE is its ability to confer antimicrobial properties to surfaces. Indeed, upon contact, this material can effectively kill enveloped viruses, such as herpes simplex virus type 1 (HSV-1) and the β-coronavirus prototype HCoV-OC43, but it is ineffective against nonenveloped viruses like human adenovirus (HAdV). Further analysis using transmission electron microscopy (TEM) on HSV-1 virions exposed to GDE showed significant structural damage, indicating that GDE can interfere with the viral envelope, potentially causing leakage. Moreover, GDE demonstrates antibacterial activity, albeit to a lesser extent, against notorious pathogens such as Staphylococcus aureus and Escherichia coli. Overall, this newly developed plasticizer shows significant potential as an antimicrobial agent suitable for use in both community and healthcare settings to curb the spread of infections caused by microorganisms contaminating physical surfaces.

A hybrid kernel-based meshless method for numerical approximation of multidimensional Fisher’s equation

We propose and analyze a meshless method of lines by considering some hybrid radial kernels. These hybrid kernels are constructed by linearly combining infinite smooth radial functions to piecewise smooth radial functions; which are then used for spatial approximation on trial spaces spanned by translates of positive definite radial functions. After spatial approximation, a high-order ODE solver is invoked for efficient and stable time-integration of the resultant semi-discrete system of ordinary differential equations (ODEs). Unlike the mesh-based method of lines, the proposed method works for arbitrary scattered data points and is equally effective for problems over non-rectangular domains. The proposed method is tested on one-, two- and three-dimensional reaction–diffusion Fisher equation for its numerical stability, accuracy, and efficiency against the contemporary meshless and mesh-based methods. The economical computational cost, improved accuracy, eigenvalues stability, and well-conditioning of system matrices are observed against RBF collocation and RBF-PS methods.

Tuning interfacial oxygen vacancy level of bismuth oxybromide to enhance photocatalytic degradation of bisphenol A

Oxygen vacancies (OVs) have garnered significant interest for their role as active sites, enhancing the catalytic efficiency of various catalysts. Despite their widespread application in environmental purification processes, the generation of OVs conventionally depends on high-temperature conditions and strong reducing agents for the extraction of surface partial oxygen atoms from catalysts. In this work, bismuth oxybromide (BiOBr) nanosheets with varying levels of OVs were synthesized via a simple and effective solvothermal method. This novel method affords precise control over the conduction band (CB) and valence band (VB) positions of BiOBr. The presence of different OVs exhibited varying photocatalytic efficiencies in the degradation of bisphenol A (BPA) under visible light irradiation, with higher levels of OVs resulting in superior photocatalytic performance. Furthermore, radical scavenger experiments demonstrated that superoxide oxides (O2•−) and holes (h+) were the primary reactive oxygen species for BPA degradation. Additionally, BiOBr-OVs exhibited excellent anti-interference and stability in water matrices containing diverse inorganic anions and organic compounds. This work provides a simple and effective approach for the fine-regulating of catalysts through interfacial defect engineering, paving the way for their practical application in environmental decontamination.

Fabrication and biomechanical characterization of a spider silk reinforced fibrin-based vascular prosthesis

With fibrin-based vascular prostheses, vascular tissue engineering offers a promising approach for the fabrication of biologically active regenerative vascular grafts. As a potentially autologous biomaterial, fibrin exhibits excellent hemo- and biocompatibility. However, the major problem in the use of fibrin constructs in vascular tissue engineering, which has so far prevented their widespread clinical application, is the insufficient biomechanical stability of unprocessed fibrin matrices.In this proof-of-concept study, we investigated to what extent the addition of a spider silk network into the wall structure of fibrin-based vascular prostheses leads to an increase in biomechanical stability and an improvement in the biomimetic elastic behavior of the grafts. For the fabrication of hybrid prostheses composed of fibrin and spider silk, a statically cast tubular fibrin matrix was surrounded with an envelope layer of Trichonephila edulis silk using a custom built coiling machine. The fibrin matrix was then compacted and pressed into the spider silk network by transluminal balloon compression.This manufacturing process resulted in a hybrid prosthesis with a luminal diameter of 4 mm. Biomechanical characterization revealed a significant increase in biomechanical stability of spider silk reinforced grafts compared to exclusively compacted fibrin segments with a mean burst pressure of 362 ± 74 mmHg vs. 213 ± 14 mmHg (p < 0.05). Dynamic elastic behavior of the spider silk reinforced grafts was similar to native arteries. In addition, the coiling with spider silk allowed a significant increase in suture retention strength and resistance to external compression without compromising the endothelialization capacity of the grafts.Thus, spider silk reinforcement using the abluminal coiling technique represents an efficient and reproducible technique to optimize the biomechanical behavior of small-diameter fibrin-based vascular grafts.

Efficient degradation of sulfamethoxazole by a peroxymonosulfate system activated by g-C3N4@polyethylene glycol-derived carbon-nitrogen nanosheets: The key roles of N and O groups

A simultaneous thermal polymerization reaction was performed with graphitic carbon nitride and polyethylene glycol to synthesize a novel metal-free carbon–nitrogen (CN) material, and the prepared material was applied to activate a peroxymonosulfate (PMS) system. Sulfamethoxazole (SMX) removal by CN7/PMS reached 93.75 % in 10 min, which was 39.86 times higher than that achieved by PMS systems alone. Material characterization showed that the pyrolysis temperature could be adjusted to modulate the N atom and functional group contents. As determined by experimental validation and DFT calculations, C = O/C-N, graphitic N and defects were the main active sites. This finding indicates that CN7 activated PMS to produce hydroxyl radicals (•OH), sulfate radicals (SO4•-) and singlet oxygen (1O2) through electrostatic interactions, nucleophilic addition, electron transfer and other pathways. Moreover, 1O2 was dominant, with a 91.58 % contribution. In addition, the materials maintained high catalytic stability in different water matrices and multiple cycling experiments. The present study innovatively illustrated the mechanism by which nitrogen-doped carbon materials activated PMS, providing a new insight into the development of highly active metal-free catalysts applied in PMS systems.