Search Results (204)

Halogenated flame retardants have been amongst the most widely used and effective solutions for enhancing fire resistance. However, their use is currently strictly regulated due to serious health and environmental concerns. In this context, phosphorus-based and mineral flame retardants have emerged as promising alternatives. Despite this, their combined use is neither straightforward nor guaranteed to be effective. This study scrutinizes the interactions between these two classes of flame retardants (FR) through a systematic analysis aimed at elucidating the antagonistic pathways that arise from their coexistence. Specifically, this study focuses on two inorganic fillers, mineral huntite and chemically precipitated magnesium hydroxide, both of which produce basic oxides upon thermal decomposition. These fillers were incorporated into a poly(butylene terephthalate) (PBT) matrix to be utilized as advanced-mattress FR coating fabric and were subjected to a series of flammability tests. The pyrolysis products of the prepared polymeric composite compounds were isolated and thoroughly characterized using a combination of analytical techniques. Thermogravimetric analysis (TGA) and differential thermogravimetric analysis (dTGA) were employed to monitor decomposition behavior, while the char residues collected at different pyrolysis stages were examined spectroscopically, using FTIR-ATR and Raman spectroscopy, to identify their structure and the chemical reactions that led to their formation. X-ray diffraction (XRD) experiments were also conducted to complement the spectroscopic findings in the chemical composition of the resulting char residues and to pinpoint the different species that constitute them. The morphological changes of the char’s structure were monitored by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). Finally, the Limited Oxygen Index (LOI) and UL94 (vertical sample mode) methods were used to assess the relative flammability of the samples, revealing a significant drop in flame retardancy when both types of flame retardants are present. This reduction is attributed to the neutralization of acidic phosphorus species by the basic oxides generated during the decomposition of the basic inorganic fillers, as confirmed by the characterization techniques employed. These findings underscore the challenge of combining organophosphorus with popular flame-retardant classes such as mineral or basic metal flame retardants, offering insight into a key difficulty in formulating next-generation halogen-free flame-retardant composite coatings. Full article

Skin aging is mainly caused by external factors like sunlight, which triggers oxidative stress and chronic inflammation. Natural halogenated flavonoids have demonstrated anti-inflammatory properties. Inspired by the macroalgae-derived bromophenol BDDE, we investigated the anti-inflammatory potential of structure-related chalcones (1–7). Chalcones 1 and 7 showed the least cytotoxicity in keratinocyte and macrophage cells. Chalcones 1, 2, 4, and 5 exhibited the most significant anti-inflammatory effects in murine macrophages after lipopolysaccharide stimulation, with chalcone 1 having the lowest IC₅₀ value (≈0.58 μM). A SNAP assay confirmed that chalcones do not exert their effects through direct NO scavenging. Symmetrical bromine atoms and 3,4-dimethoxy groups on both aromatic rings improved the anti-inflammatory activity, indicating a relevant structure–activity relationship. Chalcones 1 and 2 were selected for study to clarify their mechanisms of action. At a concentration of 7.5 μM, chalcone 2 demonstrated a rapid and effective inhibitory action on the protein levels of inducible nitric oxide synthase (iNOS), while chalcone 1 exhibited a gradual inhibitory action. Moreover, chalcone 1 effectively activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway with around a 3.5-fold increase at the end of 24 h at 7.5 μM, highlighting its potential as a modulator of oxidative stress responses. These findings place chalcone 1 as a promising candidate for skincare products targeting inflammation and skin aging. Full article

Persistent organohalogen pollutants—including halogenated nitrophenols (HNCs), trichloroethylene (TCE), and per- and polyfluoroalkyl substances (PFAS)—pose serious environmental and health risks due to their stability, toxicity, and bioaccumulation potential. This review critically assesses current remediation technologies including advanced oxidation processes (AOPs), adsorption, membrane filtration, and thermal treatments. While these methods can be effective, they are often limited by high costs, energy demands, toxic byproduct formation, and sustainability concerns. Emerging biological approaches offer promising alternatives. Among these, fungal-based degradation methods (mycodegradation) remain significantly underrepresented in the literature, despite fungi demonstrating a high tolerance to contaminants and the ability to degrade structurally complex compounds. Key findings reveal that white-rot fungi such as Phanerochaete chrysosporium and Trametes versicolor possess enzymatic systems capable of breaking down persistent organohalogens under conditions that inhibit bacterial activity. This review also identifies critical research gaps, including the need for direct comparative studies between fungal and bacterial systems. The findings suggest that integrating mycodegradation into broader treatment frameworks could enhance the environmental performance and reduce the long-term remediation costs. Overall, this review highlights the importance of diversifying remediation strategies to include scalable, low-impact biological methods for addressing the global challenge of organohalogen contamination. Full article

The presented results are a continuation of our research on the synthesis and biological properties of halogen benzofuran derivatives, particularly their anticancer potential. We examined the cytotoxicity of two derivatives, methyl 4-chloro-6-(dichloroacetyl)-5-hydroxy-2-methyl-1-benzofuran-3-carboxylate (7) and methyl 6-(dibromoacetyl)-5-methoxy-2-methyl-1-benzofuran-3-carboxylate (8), in the following human cancer cell lines: SW480, SW620, HCT116, HepG2, PC3, A549, and MDA. The MTT assay results showed that compound 7 exhibited the most promising activity against A549 cells, while compound 8 demonstrated significant activity against both A549 cells and HepG2 cells. The biological activity of these compounds was evaluated by the trypan blue assay, reactive oxygen species generation, lipid peroxidation and IL-6 secretion. To investigate the proapoptotic activity of these compounds, the two following types of tests were performed: Annexin V Apoptosis Detection Kit I and Caspase-Glo 3/7 assay. Moreover, we checked the effect of both tested derivatives on the cell cycle and tubulin polymerization. The obtained results revealed that the presence of bromine and methoxy group in the structure has an influence on the biological properties of compound 8. This derivative exhibited stronger pro-oxidative effects and proapoptotic properties compared to those observed for derivative 7. Both compounds decreased IL 6 secretion in the tested cancer cell lines; however, the stronger effect was observed for HepG2 cells. Analysis of the cell cycle in the presence of the tested compounds revealed that compound 7 induced G2/M phase arrest in HepG2 cells, while compound 8 caused cell cycle arrest at the S and G2/M phases in A549 cells. On the other hand, both derivatives had a minimal effect on tubulin polymerization. These findings suggest that compounds 7 and 8 could serve as starting points for further development of anticancer agents. Full article

Zinc-halogen batteries are usually based on two-electron transfer reactions from X⁻ to X₂. However, the halogen is capable of being further oxidized to higher valence states, thereby achieving the higher capacity of zinc- halogen batteries. Here, a six-electron reaction based on I⁻/I⁺ and Br⁻/Br⁰ is activated successfully by introducing KI into the electrolyte. ZIF-8-derived porous carbon (ZPC), serving as the host of halogen, effectively suppresses polybromide/polyiodide shuttle owing to the chemisorption/physical adsorption. Additionally, the adsorption of I⁻ on the surface of the zinc anode effectively inhibits the growth of dendrites and the formation of by-products. Consequently, zinc-bromine batteries exhibit outstanding electrochemical performance, including a specific capacity of 345 mAh g⁻¹ at 1 A g⁻¹ and an excellent capacity retention of 80% after 3000 cycles at 2 A g⁻¹. This strategy provides a novel way for enhancing the electrochemical performance of zinc-halogen batteries. Full article

Quinazolinones, a class of nitrogen-containing heterocyclic compounds, occupy a crucial position in medicinal chemistry and materials science due to their significant application potential. In recent years, the catalytic asymmetric synthesis of axially chiral quinazolinones has emerged as a prominent research area, driven by their prospective applications in the development of bioactive molecules, design of chiral ligands, and fabrication of functional materials. This review comprehensively summarizes recent advancements in the catalytic asymmetric synthesis of axially chiral quinazolinones, with a particular focus on the construction strategies for the three major structural types: the C–N axis, N–N axis, and C–C axis. Key synthetic methodologies, including atroposelective halogenation, kinetic resolution, condensation–oxidation, and photoredox deracemization, are discussed in detail. In addition, the review provides an in-depth analysis of the applications of various catalytic systems, such as peptide catalysis, enzymatic catalysis, metal catalysis, chiral phosphoric acid catalysis, and others. Despite the substantial progress made thus far, several challenges remain, including the expansion of the substrate scope, enhanced control over stereoselectivity, and further exploration of practical applications, such as drug discovery and asymmetric catalysis. These insights are expected to guide future research towards the development of novel synthetic strategies, the diversification of structural variants, and a comprehensive understanding of their biological activities and catalytic functions. Ultimately, this will foster the continued growth and evolution of this rapidly advancing field. Full article

Polybrominated diphenyl ethers (PBDEs) are synthetic halogen compounds, industrially used as flame retardants in many flammable products. PBDEs are environmentally persistent and bioaccumulative substances that were used from the 1970s and discontinued in the 1990s. PBDEs are present in air, soil, water, and food, where they remain stable for a long time. Chronic exposure to PBDEs is associated with adverse human health effects, including cancer, immunotoxicity, hepatotoxicity, reproductive and metabolic disorders, motor and hormonal impairments, and neurotoxicity, especially in children. It has been demonstrated that PBDE exposure can cause mitochondrial and DNA damage, apoptosis, oxidative stress, epigenetic modifications, and changes in calcium and neurotransmitter levels. Here, we conduct a comprehensive review of the molecular mechanisms of the neurotoxicity of PBDEs using different approaches. We discuss the main neurotransmitter pathways affected by exposure to PBDEs in vitro and in vivo in different mammalian models. Excitatory and inhibitory signaling pathways are the putative target where PBDEs carry out their neurotoxicity. Based on this evidence, environmental PBDEs are considered a risk to human public health and a hazard to biota, underscoring the need for environmental monitoring to mitigate exposure to PBDEs. Full article

In this work, we report on the fabrication of a novel Organic Double-Layer Supercapacitor (ODLSC) using recycled palm as the substrate and electrodes based on halogenated indium and copper phthalocyanines. The electrodes were characterized using Reflectance, the Kulbeka–Munk function, and Fluorescence. Finally, their electrical behavior was evaluated, and the results were compared with those obtained for a more conventional supercapacitor fabricated on polyethylene terephthalate substrate and using indium tin oxide film for electrodes. Based on the experimental measurements of the fabricated ODLSC, the parameter identification of the classical equivalent circuit model was carried out using the Least Squares of Orthogonal Distances (LSOD) algorithm. The results indicated that the palm supercapacitor exhibited behavior more like that of traditional supercapacitors, as the root square mean error (RMSE) values in the model approximation of the experimental data were in the order of ${10}^{-7}$. Furthermore, the models obtained allowed a determination of the device’s Electrical Impedance Spectroscopy (EIS), revealing that the Palm SC-T1 exhibited capacitive behavior. In contrast, the manufactured Palm SC-T2, PET SC-T1, and PET SC-T2 devices exhibited inductive behavior. All the materials used in this work, such as the substrates, electrodes, separator membranes, and electrolytes, have a high potential to be used in organic supercapacitors. Full article

Tris(2-chloroethyl) phosphate (TCEP) is a representative chlorinated organophosphate flame retardant (OPFR) that demonstrates greater persistence than other non-halogenated alkyl or aryl OPFRs. Although TCEP has been shown to accumulate significantly in the environment and contribute to testicular toxicity and spermatogenic dysfunction, the precise underlying factors and mechanisms of action remain unclear. Herein, male ICR mice were gavaged with corn oil, 50 mg/kg body weight (bw) TCEP, or 100 mg/kg bw TCEP from postnatal day (PND) 22 to PND 35. TCEP exposure resulted in the disruption of blood-testis barrier (BTB) integrity and in abnormal testicular development. Considering that Sertoli cells constitute the primary target of toxicants and that TCEP induces oxidative stress in the testis and other organs, we focused on ferroptosis in Sertoli cells. Our findings revealed a significant increase in ferroptosis in the testes and Sertoli cells following TCEP exposure, and we observed functional restoration of Sertoli cell junctions upon treatment with the ferroptosis inhibitor ferrostatin-1. Furthermore, ferritin heavy chain 1 (FTH1) was markedly reduced in TCEP-exposed testes and Sertoli cells. Since nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy is essential for the degradation of FTH1, we assessed ferritinophagic activity and found significant upregulation of NCOA4, ATG5, ATG7, and LC3B II/I in TCEP-exposed testes and Sertoli cells. These results strongly suggest that TCEP triggers Sertoli cell ferroptosis by activating ferritinophagy that leads to reduced expression of BTB-associated proteins, ultimately causing BTB disruption and testicular developmental toxicity. Full article

As high-grade gold deposits are progressively depleted, the proportion of refractory gold ores in total reserves is continuously increasing, making gold recovery from refractory ores an inevitable trend in the future development of the gold industry. This study briefly analyzes the challenges faced during the leaching process of refractory gold ores under ambient conditions, and provides a detailed discussion on two acidic pretreatment technologies—pressure oxidation and bio-oxidation—as well as three acidic gold recovery technologies—thiosulfate leaching process, halogen leaching process, and thiocyanate leaching process. Additionally, this paper compares and analyzes the advantages and limitations of these acidic pretreatment and hydrometallurgical gold recovery technologies. The goal is to provide a comprehensive review of pretreatment technologies and leaching agents for refractory gold ores under acidic conditions (pH = 1–5), offering a reference for selecting appropriate treatment processes in the future, and to explore the potential development of acidic pretreatment and recovery technologies for refractory gold ores. Full article

Polyamide-based glass fibre-reinforced composites are extensively used in electrical and automotive applications due to their excellent mechanical, thermal, and electrical properties. However, prolonged exposure to high temperatures can lead to significant degradation, affecting their long-term performance and reliability. This study investigates the thermal ageing behaviour of polyamide 6,6 composites containing halogenated flame retardants used for electrical applications. The objective of this research is to evaluate the extent of degradation through accelerated ageing tests and to develop an Arrhenius-type ageing model to predict the long-term performance of these materials. This study examines the effects of thermal ageing at temperatures between 160 and 210 °C on flexural properties and explores the underlying degradation mechanisms. Results indicate that short-term exposure to high temperatures can enhance flexural strength due to annealing effects, which are eventually outweighed by thermal oxidation and increased crystallinity, leading to an increase in brittleness. The derived Arrhenius model, with an activation energy of 93 kJ/mol, predicts a service life of approximately 25 years at 80 °C, but a significantly shorter one at 130 °C. These findings underscore the importance of considering thermal ageing effects in the design and application of PA66 composites in high-temperature environments. Full article

One-component or bifunctional organocatalysts are some of the most capable compounds to perform the synthesis of cyclic carbonates from epoxides and carbon dioxide (CO₂) since the presence of a co-catalyst is not required. In this study, we designed, synthesized, and evaluated five halogenated compounds as bifunctional organocatalysts for this catalytic transformation. Among them, 1,3-dimethylimidazolium iodide (1) exhibited the highest catalytic efficiency, enabling the synthesis of a broad range of monosubstituted cyclic carbonates with diverse functional groups under mild conditions (80 °C, 20 bar CO₂) within 1 h, using only 1 mol% catalyst loading. Remarkably, this organocatalyst also facilitated the synthesis of five internal cyclic carbonates and a carvone-derived exo-cyclic carbonate, which was obtained for the first time without the use of a metal catalyst, under more demanding conditions. A mechanistic proposal was developed through a combination of ¹H-NMR studies and density functional theory (DFT) simulations. Styrene oxide and cyclohexene oxide were used as model substrates to investigate the reaction pathway, which was computed using an optimized climbing-image nudged elastic band (CI-NEB) method. The results revealed the critical role of 1,3-dimethylimidazolium iodide in key reaction steps, particularly in facilitating the epoxy ring opening process. These findings highlight the potential use of bifunctional compounds as efficient and versatile catalysts for CO₂ valorization. Full article

Background/Objectives: Brain cancer is notoriously resistant to traditional treatments, including radiotherapy. Microbeam radiation therapy (MRT), arrays of ultra-fast synchrotron X-ray beams tens of micrometres wide (called peaks) and spaced hundreds of micrometres apart (valleys), is an effective alternative to conventional treatments. MRT’s advantage is that normal tissues can be spared from harm whilst maintaining tumour control. Combining MRT with targeted radiosensitisers, such as nanoparticles, chemotherapeutic drugs, and halogenated pyrimidine drugs, can further improve radiotherapy by enhancing radiation damage. However, the underlying mechanisms of MRT are still being understood, which is essential to ensuring the reliable and successful use of MRT. Methods: An in vitro study was performed using γH2AX imaging, and quantification was performed via confocal microscopy and a clonogenic cell survival assay. Results: We show that methotrexate chemotherapeutics and iododeoxyuridine enhance MRT cell-killing and thulium oxide nanoparticles (TmNPs) broaden MRT peaks, and using γH2AX immunofluorescent confocal microscopy to quantify DNA damage, we further our knowledge of MRT mechanisms. γH2AX images verify the biological responses of cells aligning with the physical collimation of MRT, and we can accurately measure MRT microbeam characteristics bio-dosimetrically. The peak-to-valley dose ratio (PVDR), the ratio of the peak dose to the valley dose that characterises an MRT field, was accurately measured biologically using γH2AX imaging, despite studies previously finding this challenging. Conclusions: The measurement of biological PVDR has been performed for the first time with high-Z radiosensitisers, including nanoparticles, and several novel radiosensitiser-enhanced MRT mechanisms were discovered. Our results deepen our understanding of MRT with radiosensitisers, and can contribute to its accurate and future successful use in treating cancer. Full article

Photocatalysis offers a powerful approach for water purification from toxic organics, hydrogen production, biosolids processing, and the conversion of CO₂ into useful products. Further advancements in photocatalytic technologies depend on the development of novel, highly efficient catalysts and optimized synthesis methods. This study aimed to develop a laser synthesis technique for bismuth oxyhalide nanoparticles (NPs) as efficient and multifunctional photocatalysts. Laser ablation of a Bi target in a solution containing halogen salt precursors, followed by laser plasma treatment of the resulting colloid, yielded crystalline bismuth oxyhalides (Bi_xO_yX_z, where X = Cl, Br, or I) NPs without the need for additional annealing. The composition, structure, morphology, and optical properties of the synthesized Bi_xO_yX_z (X = Cl, Br, I) NPs were characterized using XRD analysis, electron microscopy, Raman spectroscopy, and UV-Vis spectroscopy. The effect of the halogen on the photocatalytic activity of the double oxides was investigated. The materials exhibited high photocatalytic activity in the degradation of persistent model pollutants like Rhodamine B, tetracycline, and phenol. Furthermore, the Bi_xO_yX_z NPs demonstrated good efficiency and high yield in the selective oxidation of 5-hydroxymethylfurfural (5-HMF) to 2,5-furandicarboxylic acid (FDCA). The obtained results highlight the promising potential of this laser synthesis approach for producing high-performance bismuth oxyhalide photocatalysts. Full article

Anesthetic gases enter the environment primarily through patient exhalation and venting from scavenging systems directly into the atmosphere. Emissions of halogenated anesthetic gases like halothane, isoflurane and sevoflurane are of concern due to their high global warming potential, highlighting the need to mitigate their environmental impact. Photocatalytic oxidation has been proposed as a potential option for emission control and indoor air treatment, but data on its use for various halogenated anesthetics is very limited. In this work, photocatalytic oxidation efficiency for the degradation of halothane was studied by varying the method for catalyst support and catalyst mass loading. Approximately 99.9% of halothane (1296 mg/m³) in air was degraded with a TiO₂ photocatalyst under UVC light (254 nm) in 35 min in a recirculating batch photoreactor. The optimized conditions for halothane demonstrated a similar although faster photocatalytic degradation efficiency for isoflurane (99.8% in 20 min, 911 mg/m³) and sevoflurane (>98% in 10 min, 847 mg/m³). The results presented here suggest that a UV–photocatalysis is a promising technique to treat such anesthetic gases before being released into the environment by scavenging systems, although significant work remains to identify the potential by-products and optimal photoreactor designs for efficient long-term operation. Full article