Search Results (213)

Despite their high effectiveness in reducing material flammability, modern brominated flame retardants (BFRs) remain poorly understood with respect to the toxic substances they generate during combustion. BFRs such as 1,2-bis(pentabromodiphenyl)ethane (DBDPE) and tetrabromophthalate diol (PHT4-DIOL) have been introduced following the limitations on legacy brominated additives. However, their thermal decomposition pathways and toxic product emission profiles under real fire conditions remain poorly characterized. Exposure to elevated temperatures may promote the formation of halogenated toxicants and environmentally persistent compounds, raising concerns that extend beyond conventional fire-safety performance. The combustion behavior of DBDPE-, PHT4-DIOL-, and BFR-containing epoxy resins was investigated using a steady-state tube furnace designed to reproduce realistic fire scenarios. Controlled temperature and ventilation conditions were applied to simulate representative stages of fire. Combustion emissions were comprehensively characterized using Fourier transform infrared spectroscopy (FT-IR) to analyze asphyxiant and irritant gases and solid-phase microextraction gas chromatography–mass spectrometry (SPME-GC-MS) for volatile and semi-volatile organic compounds. The results presented that the incorporation of BFRs substantially altered combustion emission profiles, promoting the formation of brominated and mixed-halogenated species alongside toxic gaseous products. Significant differences in the composition and distribution of combustion byproducts were observed between non-modified and BFR-containing materials, indicating that the environmental and toxicological consequences of these additives cannot be adequately assessed solely through flammability-reduction metrics. These conclusions provide new knowledge of the environmental impacts of brominated flame retardants and highlight the importance of integrated fire-safety assessment strategies that simultaneously consider flame-inhibition efficiency, combustion toxicity, and environmental persistence. Full article

Organophosphate flame retardants (OPFRs) are widely used as flame-retardant additives in plastics, electronics, and building materials. However, growing evidence suggests these compounds may pose significant neurotoxic risks. This study evaluated phenotypic alterations, such as cell viability, reactive oxygen species generation, and acetylcholinesterase activity, induced by seven widely detected OPFRs in SH-SY5Y human neuroblastoma cells. Aromatic OPFRs such as triphenyl phosphate (TPhP), 2-ethylhexyldiphenyl phosphate (EHDPhP) and tricresyl phosphate (TCP) exhibited the strongest effects, including decreased cell viability, increased oxidative stress and AChE inhibition. Therefore, 3D brain organoid models were used to further explore the potential lipidomic alterations induced by aromatic OPFRs. Lipidomic analysis of brain organoids exposed to aromatic OPFRs (TPhP, EHDPhP and TCP) showed significant alterations across major lipid classes, especially glycerophospholipids, sphingolipids, and glycerolipids. The depletion of bis(monoacylglycerol)phosphate (BMP) species suggests perturbations in endolysosomal lipid homeostasis and membrane trafficking pathways. Increased levels of ether-linked lysophosphatidylcholine (LPC-O) species, together with altered phosphatidylethanolamine (PE) and phosphatidylserine (PS) species, indicate extensive membrane lipid remodeling and changes in cellular signaling. Furthermore, the accumulation of diacylglycerol (DG) and triacylglycerol (TG) species points to disturbances in lipid storage and metabolism. Overall, these findings indicate that aromatic OPFRs induce cytotoxicity, oxidative stress, and alteration of cholinergic function, and are associated with lipid dysregulation linked to neurotoxicity in brain organoids. Future research should explore chronic low-dose exposure and long-term neurological effects. Full article

Background/Objectives: Lavandula cariensis species is cultivated uncommonly in the western region of Turkey. The colloquial appellations avayianos, karabasi, and myra are used to refer to the L. cariensis plant. The essential oil of L. cariensis was studied for its potential antiglaucoma, antioxidant, antidiabetic, and acetylcholinesterase inhibitory effects. Methods: The inhibitory effect of the essential oil of L. cariensis on the acetylcholinesterase (AChE), carbonic anhydrase II (CA II), and α-amylase enzymes was determined. Therefore, chemical profiles of L. cariensis’ essential oil were identified using Gas Chromatography Mass Spectrometry (GC-MS) and as Chromatography with Flame Ionization Detection (GC-FID) analyses. Results: Camphor (39.73%), fenchone (19.49%), exobornyl acetate (6.81%), camphene (5.49%), and eucalyptol (5.49%) were the most abundant compounds in L. cariensis essential oil. Radical scavenging effect of the essential oil of L. cariensis was examined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC₅₀: 231.0 ± 0.094 μg/mL) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) (IC₅₀: 7.45 ± 0.013 μg/mL) radicals. Also, the ferric ions (Fe³⁺), cupric ions (Cu²⁺), and Fe³⁺-2,4,6-tri(2-pyridyl)-S-triazine (TPTZ) complex reducing capabilities were studied. Additionally, essential oil of L. cariensis indicated a comparable level of inhibition towards hCA II (IC₅₀: 276.42 μg/mL), AChE (IC₅₀: 14.22 μg/mL), and α-amylase (IC₅₀: 475.63 μg/mL) enzymes. Conclusions: The evaluation of the antioxidant capabilities and enzyme inhibition profiling of the essential oil of L. cariensis will be made possible by this comprehensive study, which serves as a springboard for further research. The essential oil of L. cariensis demonstrated enzyme-inhibitory activities against target enzymes associated with Alzheimer’s disease, diabetes, and glaucoma. Also, this study’s in vitro inhibition suggests promising prospects. Full article

The use of natural products as alternatives to synthetic fungicides has gained increasing importance in crop protection. Among these, clove (Syzygium aromaticum) and its active compound, eugenol, are well known for their antifungal properties. However, it remains unclear whether the antifungal activity of clove is primarily driven by its major constituent, eugenol, or whether the whole essential oil exhibits greater or synergistic efficacy. Addressing this question is crucial for optimizing their application as biofungicidal agents; The chemical composition of clove essential oil was characterized using gas chromatography–flame ionization detection (GC-FID) and gas chromatography–mass spectrometry(GC-MS). The antifungal activity of the essential oil and pure eugenol (300 µg/mL) was evaluated in vitro against Botryotinia fuckeliana, Rhizoctonia solani, and Verticillium dahliae on potato dextrose agar (PDA). Mycelial growth inhibition was quantified, and data were analyzed using two-way analysis of variance (ANOVA) followed by Tukey’s honestly significant difference (HSD) test (α = 0.05); Eugenol exhibited higher antifungal activity than the essential oil across all tested species. V. dahliae was completely inhibited (100%) by eugenol, while the essential oil showed lower efficacy. Despite the high eugenol content (87.3%) in the oil, its reduced activity suggests that minor constituents may modulate overall antifungal performance. These findings demonstrate that eugenol is more effective than clove essential oil as an antifungal agent. This highlights that the biological activity of clove is largely driven by its major active component, providing key insights for the development of more efficient biofungicidal strategies. Full article

Ambrosia arborescens Mill., a native medicinal plant traditionally used in the Andean region, has a poorly characterized essential oil (EO), with no prior reports on its anticholinesterase or antioxidant potential. As a first report and preliminary screening study, this work characterizes the chemical composition of the EO and evaluates its acetylcholinesterase (AChE) inhibitory and antioxidant activities. The EO was isolated by hydrodistillation and analyzed using gas chromatography coupled with mass spectrometry (GC–MS) and flame ionization detection (GC-FID). The biological activities were evaluated using the Ellman method to determine AChE inhibition and using ABTS and DPPH assays to determine antioxidant activity. Analysis of the chemical composition revealed 31 compounds, and the major components were γ-curcumene (28.63%), trans-muurola-4(14),5-diene (27.85%), and eucavone (18.46%). The EO showed moderate AChE inhibitory activity, with an IC₅₀ value of 28.04 ± 1.02 µg/mL, and limited antioxidant activity, with ABTS SC₅₀ = 373.75 ± 1.30 µg/mL and DPPH SC₅₀ = 1101.84 ± 1.63 µg/mL. These findings demonstrate that the EO possesses selective anticholinesterase activity and limited antioxidant capacity. Given the structural diversity of its constituents, the observed bioactivity is likely the result of the combined contributions of multiple components; however, the specific active constituents and potential synergistic interactions require further investigation through bioassay-guided fractionation. These findings represent the first preliminary screening of the biological activities of A. arborescens EO and provide a foundation for future bioactivity-guided investigations. Full article

Polybrominated diphenyl ethers (PBDEs), widely used as brominated flame retardants, are known to exert persistent adverse effects on the immune systems of humans and other organisms. Previous studies have demonstrated that 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47), a prevalent congener, induces apoptosis, impairs phagocytic function, and triggers aberrant immune-inflammatory reactions in RAW264.7 macrophages via the induction of elevated intracellular reactive oxygen species (ROS). However, the underlying regulatory mechanism remains unclear. The nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) signaling pathway is a key cellular defense system against oxidative stress. In this study, we investigated the role of the Nrf2/ARE pathway in BDE-47-induced macrophage immunotoxicity. Network toxicology analysis identified Nrf2 as a hub gene within the BDE-47-associated immunotoxicity network. Molecular docking and molecular dynamics simulations suggested a potential interaction between BDE-47 and the Keap1-Nrf2 complex, with moderate binding affinity. Experimental studies in RAW264.7 cells showed that BDE-47 exposure activated the Nrf2/ARE pathway, as evidenced by Nrf2 nuclear translocation and the differential upregulation of downstream genes (GCLC, GCLM, HO-1, NQO1, SOD1, and CAT). Importantly, Nrf2 knockdown via lentiviral shRNA or pharmacological inhibition with brusatol significantly exacerbated BDE-47-induced apoptosis and immune dysfunction, including enhanced pro-inflammatory cytokine production and impaired phagocytosis. These results demonstrate that Nrf2/ARE pathway activation represents an adaptive antioxidant response and contributes to limiting BDE-47-induced cytotoxicity and immune impairment in macrophages. Full article

Oxy-fuel combustion is a near-zero emission technology that utilizes high-concentration O₂ in place of air, combined with recycled flue gas, to achieve efficient combustion and enable effective CO₂ capture. In this study, air (21% O₂/79% N₂) was used as the control atmosphere, and rice straw combustion experiments were conducted using thermogravimetric analysis and differential scanning calorimetry and differential scanning calorimetry coupled with mass spectrometry (TG-MS) at heating rates of 10, 20, and 30 °C/min under oxy-fuel conditions of 30% O₂/70% CO₂, 50% O₂/50% CO₂, and 70% O₂/30%CO₂. The combustion behavior, pollutant emissions, reaction kinetics, and underlying mechanisms were systematically evaluated. The results show that CO₂ in oxy-fuel atmospheres exhibits a higher thermal inertia, due to its greater density and specific heat capacity, thereby enhancing flame stability. Oxy-fuel atmospheres reduce the ignition temperature (Tᵢ) and burnout temperature (T_f), shorten the combustion duration, shift DTG and DSC peaks to lower temperatures, and result in sharper peaks along with an increased ignition index (Cᵢ), burnout index (C_b), and comprehensive combustion index (S). Mass spectrometry (MS) analysis reveals that oxy-fuel atmospheres combined with heating rates of 20–30 °C/min suppress O₂ diffusion and thermal NO formation, reducing NO_x emissions by over 75% and simultaneously inhibiting the release of SO₂ and COS. Kinetic analysis using the FWO and Friedman methods shows that the activation energy decreases from 210.5 kJ/mol and 219.1 kJ/mol under air conditions to 110.5 kJ/mol and 114.6 kJ/mol in oxy-fuel atmospheres, representing a reduction in reaction barriers of 47.5% and 47.7%, respectively. The reaction mechanisms were identified as three-dimensional diffusion-controlled processes at heating rates of 20–30 °C/min, and random nucleation followed by growth under high O₂ concentration conditions at a heating rate of 30 °C/min. Optimizing the combustion atmosphere and heating rate enhances the rice straw combustion efficiency and reduces pollutant emissions, thereby providing theoretical support for its clean and efficient utilization. Full article

Triphenyl phosphate (TPHP), a typical organophosphate flame retardant, has been listed as an emerging pollutant, yet its biodegradation remains poorly studied. Herein, an efficient TPHP-degrading marine bacterium, Pseudomonas abyssi RL-WG04, was isolated from mangrove sediments, which could degrade 95.22% of 100 mg/L TPHP within 120 h. RL-WG04 exhibited good tolerance to varied environmental conditions, maintaining over 70% TPHP degradation percentages (100 mg/L, 7 d) across 20–50 °C, pH 7.0–9.0, and salinity 2.0–4.0% (NaCl, w/v). Organic solvents (p-xylene, biphenyl, toluene and ethyl acetate, 0.5% v/v) had a negligible impact, whereas metal ions (Mn²⁺, Fe³⁺, Ca²⁺, Cu²⁺, Mg²⁺, Zn²⁺, and Co²⁺) strongly inhibited degradation, especially at 1 mM. Under optimized conditions, TPHP degradation by RL-WG04 followed the improved Gompertz model (R² = 0.99927). Metabolite identification indicated that RL-WG04 transformed TPHP into phenol but failed to utilize phenol for growth because of the phenol 2-monooxygenase deficiency. Nevertheless, the constructed consortia of RL-WG04 and Pseudomonas sp. RL-LY03 (phenol-degrading bacterium) achieved complete TPHP degradation and cell proliferation. Additionally, RL-WG04 could efficiently remove TPHP (25 mg/kg) from clay and sandy mangrove sediments with 100% and 90.04% removal percentages, respectively. Overall, this work provides novel insights into the fate of TPHP and a potential approach for its remediation. Full article

Tri-o-cresyl phosphate (TOCP) is widely used as a plasticizer, flame retardant, and lubricant additive, but has been reported to impair spermatogenesis. However, how TOCP affects spermatogenesis remains unclear. Therefore, the objective of this study is to investigate the underlying mechanism by which TOCP disrupts spermatogenesis. In order to achieve this, adult male mice were orally administered TOCP at doses of 0, 200, or 400 mg/kg for two weeks, and we found that TOCP exposure reduced the number of germ cells and decreased sperm density. Moreover, the numbers of PCNA-positive cells and phospho-histone H3 (Ser10)-positive cells in mouse testicular tissues were significantly decreased following TOCP treatment, indicating that germ cell proliferation may be impaired. In addition, TOCP did not affect the protein expression of neuropathy target esterase (NTE) in testicular tissues but markedly inhibited its enzymatic activity (by approximately 30% relative to the control level). In vitro experiments further demonstrate that TOCP suppressed cell proliferation and mitotic progression in mouse GC-1 spg cells and excessively activated endoplasmic reticulum (ER) stress. Treatment with 4-phenylbutyric acid (4-PBA), an ER stress inhibitor, partially reversed the TOCP-induced inhibition of cell proliferation and mitosis. Furthermore, TOCP inhibited NTE activity in GC-1 spg cells, and NTE knockdown produced a phenotype similar to that observed after TOCP exposure, characterized by suppressed cell proliferation and mitotic progression. Surprisingly, ER stress was not activated in GC-1 spg cells following NTE knockdown. Collectively, these findings suggest that TOCP may impair spermatogenesis by inhibiting the proliferation and mitotic progression of mouse germ cells, potentially through mechanisms involving excessive activation of ER stress or suppression of NTE activity. Full article

Against the backdrop of a low-carbon economy, the control of soot emissions from combustion processes is of paramount importance. In this study, the effects of CO₂ dilution on soot formation in ethylene laminar diffusion flames are investigated through a combination of experimental measurements and numerical simulations. In addition, a virtual species, denoted as F_xCO₂, is introduced to progressively decouple the individual mechanisms by which different effects suppress soot formation. The results indicate that increasing the CO₂/N₂ dilution ratio leads to reductions in both the peak flame temperature and the soot volume fraction, with CO₂ exhibiting a more pronounced inhibitory effect than N₂. The decoupling analysis reveals that the dilution effect and the chemical effect are the dominant contributors to flame temperature reduction. The soot-inhibiting effectiveness of the individual effects follows the order: dilution effect > thermal effect > chemical effect > density effect > transport effect. With respect to their influence on C₂H₂ concentration, the effects are ranked as: dilution effect > chemical effect > transport effect > thermal effect > density effect. The chemical effect suppresses the formation of OH radicals, thereby reducing the flame temperature and H radical concentration. In contrast, the dilution effect enhances soot oxidation by increasing the OH radical concentration, effectively inhibiting soot particle formation. Full article

Methane oxy-combustion is a promising carbon capture pathway due to the high CO₂ concentration in the exhaust; however, combustion in pure oxygen produces excessively high flame temperatures that impair ignition and operational stability. To mitigate these effects, steam dilution is commonly applied, but it significantly prolongs ignition delay time (IDT). To address these limitations, hydrogen enrichment is proposed as a reactivity-enhancement strategy. The objective of this study is to quantify the combined effects of steam dilution and hydrogen enrichment on ignition behaviour, carbon species formation, and flame temperature in methane oxy-combustion, considering both ignition onset and equilibrium combustion states. A detailed numerical investigation is conducted using zero-dimensional constant-pressure simulations with detailed chemical kinetics implemented in Cantera, formulated in mixture-fraction space. IDT, CO/CO₂ formation, and adiabatic flame temperature are analysed over steam dilution levels of 0–40%, hydrogen enrichment up to 5% by mass, and initial temperatures between 1050 and 1200 K. The model is validated against experimental data for adiabatic flame temperature and key radical species. Results demonstrate that steam dilution effectively reduces the peak adiabatic flame temperature (by more than 300 K at 40% steam) and enhances the CO₂ mass fraction in the equilibrium state near the stoichiometric mixture fraction, but increases IDT by approximately 100–200% across the mixture-fraction range. Hydrogen enrichment strongly counteracts this inhibition, reducing IDT by up to one order of magnitude under high steam dilution (30–40%) while simultaneously suppressing CO. At the stoichiometric mixture fraction, H₂ addition decreases equilibrium CO₂ formation, indicating a trade-off between enhanced ignition reactivity and ultimate carbon conversion under equilibrium conditions. The use of steam dilution as a temperature-control strategy and hydrogen enrichment as a reactivity enhancer identifies a favourable mixture-fraction window. Full article

Cotton fabrics are widely used in textiles due to their comfort and breathability, but their high flammability (limiting oxygen index (LOI) ≤ 18%) poses serious safety risks. While conventional flame-retardant treatments often rely on synthetic chemicals or toxic additives, biobased alternatives remain underdeveloped. The flame resistance of cotton fabrics may be enhanced using multilayer biocoatings of chitosan and sodium alginate applied via layer-by-layer (LBL) assembly—a sustainable and scalable approach. Cotton samples were coated with chitosan and sodium alginate bilayers (1, 2, 5, and 10 layers) using the LBL method. Flame resistance was evaluated using vertical flame tests and limiting oxygen index (LOI) testing according to ASTM D2863-09. The sample coated with 10 bilayers significantly outperformed uncoated cotton and lower-layer samples. With a char length of 9.72 cm (68% reduction), no dripping was observed in the vertical flame tests, and the LOI value was 23.47% compared to uncoated cotton (LOI = 18.04%). These improvements were attributed to the formation of a cohesive and protective carbon layer, which is likely capable of inhibiting the formation of flammable gases. Biomaterial multilayer coatings made from biomaterials, such as chitosan and sodium alginate, represent a promising and environmentally friendly alternative to traditional methods in improving cotton’s flame resistance. The development of this technology points to potential applications in protective textiles and industrial safety clothing. Notably, chitosan and sodium alginate coatings are biocompatible. The term “biomaterials” refers to materials intended for interaction with biological systems, particularly for biomedical-related applications. The term “biobased materials” is used exclusively to describe materials derived from renewable biological sources. Full article

This study presents a sustainable strategy for improving the thermal properties of pine wood through the application of calcium carbonate nanopowder (CCNP) chelated with polycarboxylic acids (citric acid (CA) and tartaric acid (TA)) as coatings. The chelation reaction was confirmed by the detection of carbon dioxide (CO₂) gas. CCNP was characterized using microscopy and particle size analysis. The formation of crystalline calcium citrate and calcium tartrate was verified using FTIR and Raman spectroscopies, and XRD analysis. Wood treatment was conducted using different volumetric ratios of CA and TA. The CA-TA-treated (coated) wood blocks achieved the highest mass gain after treatment of around 89%, while the pure TA treatment exhibited enhanced leaching resistance, maintaining around 69% mass gain after leaching test. TGA conducted under oxidative (air) conditions showed that the coatings promoted char formation and produced inorganic residues from 6.4% to 7.8%, with the control resulting in negligible residual mass. Flame retardancy tests showed that the chelated coatings effectively delayed combustion and inhibited heat transfer, with the TA treatment showing improved flame retardancy performance by limiting the surface temperature to ~200 °C after 60 s of exposure, as compared to >550 °C for the control. Full article

Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) is a ubiquitous organophosphate flame retardant posing potential threats to reproductive health. Given that TDCIPP toxicity is often linked to oxidative stress, pyrroloquinoline quinone (PQQ), a potent natural antioxidant and mitochondrial nutrient, was hypothesized to mitigate these adverse effects. This study investigated the impact of TDCIPP exposure on the in vitro maturation of mouse oocytes and evaluated the protective role of PQQ. Using an in vitro maturation model, we assessed the toxic effects of TDCIPP by examining the first polar body extrusion (PBE) rate and cumulus expansion, followed by analyses of oxidative stress (ROS and GSH), mitochondrial integrity (ATP content and distribution), and apoptosis-related markers through transcriptome sequencing (Smart RNA-seq), quantitative real-time PCR, and immunofluorescence. The results demonstrated that TDCIPP significantly suppressed cumulus expansion and reduced the PBE rate. Mechanistically, TDCIPP induced severe oxidative stress, disrupted mitochondrial function, and activated the apoptotic pathway. Furthermore, TDCIPP triggered early apoptotic signaling by downregulating Bcl-2 and upregulating Bax. Notably, supplementation with PQQ effectively reversed these detrimental effects by reducing intracellular ROS levels, maintaining GSH content, preserving mitochondrial density and ATP production, and inhibiting apoptosis. In conclusion, our findings provide new insights into the gamete toxicity of TDCIPP and suggest that PQQ may serve as a potential therapeutic agent to protect oocyte quality against environmental pollutant-induced damage. Full article

Essential oils (EOs) have gained attention as biodegradable biopesticides for sustainable crop protection. This study investigated the chemical composition, antifungal activity and antioxidant potential of EOs from Mentha pulegium (EO-MP) and Cymbopogon citratus (EO-CC) against Bipolaris oryzae, the causal agent of rice brown spot, including the first quantitative determination of IC₅₀ values through standardized dose–response modeling and temporal evaluation of antifungal efficacy. Volatile profiles of both EOs were characterized by gas chromatography coupled with flame ionization detection (GC-FID) and gas chromatography–mass spectrometry (GC-MS). Antifungal activity was evaluated in vitro by a poisoned food assay at six concentrations ranging from 9.375 to 300 µL per plate (0.469–15.000 µL/mL PDA medium). Mycelial growth inhibition was assessed after 7 and 14 days of incubation. Antioxidant potential was determined by ferric reducing antioxidant power (FRAP) assay while protection against lipid oxidative damage was evaluated through inhibition of lipid peroxidation by the thiobarbituric acid reactive substances (TBARS) method. Both EO-MP and EO-CC exhibited strong, dose-dependent antifungal effects and achieved complete inhibition of mycelial growth at ≥37.50 µL per plate (1.875 µL/mL PDA) and ≥18.75 µL per plate (0.938 µL/mL PDA), respectively. EO-MP showed high reducing capacity (its FRAP value was 1.45 Trolox equivalent antioxidant capacity—TEAC) and high inhibition of lipid peroxidation (89.09%). Similarly, EO-CC exhibited a FRAP value of 1.55 TEAC and lipid peroxidation inhibition of 87.66%. These findings highlight the biofungicidal activity and multifunctional antioxidant-related properties of EOs from M. pulegium and C. citratus, supporting their potential application as eco-friendly tools for sustainable rice brown spot management. Full article