Chemosphere最新文献

The objective of the subsequent study was to examine the probability of PFAS (per- and polyfluorinated alkyl substances) binding to various NHRs (nuclear hormone receptors) and to identify their structural features that contribute most to the binding score (BS). We evaluated the BS for PFAS in relation to 7 selected NHRs - 4 with additional antagonist forms (Retinoid X receptor alpha - RXRα, Liver X receptor alpha - LXRα, Liver X receptor beta - LXRβ, Estrogen receptor alpha - ERα, Estrogen receptor alpha antagonist - anti-ERα, Estrogen receptor beta - ERβ, Estrogen receptor beta antagonist - anti-ERβ, Glucocorticoid receptor - GR, Glucocorticoid receptor antagonist - anti-GR, Androgen receptor - AR, Androgen receptor antagonist - anti-AR). We based our study on the results of molecular docking, which we used to develop MLR-QSAR (Multiple Linear Regression - Quantitative Structure-Activity Relationship) models. The models we developed allowed us to predict the BS for an extensive set of PFAS compounds from the NORMAN database (more than 4000) - virtual screening. The probability of PFAS binding to selected receptors was determined by structural features such as particle size, branching, and fluorine content. These variables were also identified in the literature reports of experimental studies as the most important for this group of compounds. The research focused on receptors from the terpenoid group. The RXRα, LXRα and β, GR, and anti-GR receptors were shown to be the group less likely to be affected by PFAS. Sex hormones such as AR, anti-AR, ERα and ERβ with their antagonist forms are the most affected.

This study investigated the green synthesis of silver nanoparticles (Ag-NPs) and zinc oxide nanoparticles (ZnO-NPs) using an aqueous extract of stingless bee honey (SBH) as a reducing and stabilising agent. The rich compositions of SBH containing flavonoids, phenolics, organic acids, sugars, and enzymes makes the SBH extract an ideal biocompatible precursor for the NPs synthesis. Physicochemical characterisation of the synthesised NPs was performed using UV-Vis spectroscopy, FESEM, TEM, XRD, and FTIR spectroscopy. The results revealed that the Ag-NPs and ZnO-NPs exhibited polydispersity, with size ranges between 25-50 nm and 15-30 nm, respectively. A majority of the NPs possessed a spherical morphology. Furthermore, the study evaluated the antimicrobial activity of the SBH-based NPs against gram-positive (Staphylococcus aureus, ATCC 43300) and gram-negative (Escherichia coli, ATCC 25922) bacteria. The findings demonstrated significantly higher antimicrobial efficacy of the Ag-NPs with a zone of inhibition (ZOI) of 16.91 mm against S. aureus, and 17.43 mm against E. coli compared to the ZnO-NPs which having a ZOI of 13.05 mm and 14.01 mm, respectively. Notably, cytotoxicity assays revealed no adverse effects of the synthesised NPs on normal mouse fibroblast (3T3) and human lung fibroblast (MRC5) cells up to 100 μg/ml of concentration. These findings suggest the potential of SBH-based Ag-NPs and ZnO-NPs as safe and effective antibacterial agents for various applications, including pharmaceuticals, cosmetics, ointments, and lotions.

Exploiting solid powder fluorescence holds significant potential in diverse domains including medicine and forensics. Conventional fingerprint detection methods often fall short due to low contrast, sensitivity, and high toxicity. To addressing these challenges, we present a novel method for latent fingerprint detection using fluorescent carbon dots (CDs) encapsulated into conventional or mesoporous SiO₂ colloidal spheres (CD@SiO₂ or CDs@m-SiO₂) through a surface functionalization-assisted cooperative assembly process. The synthesized monodisperse CDs@SiO₂ and CDs@m-SiO₂ spheres, with tuning particle size, adjustable porosity and pore size, and highly dispersed CDs, exhibit improved fingerprint visibility and contrast on various substrates such as glass, stainless steel, and plastic. CDs located in SiO₂ with excellent affinity effectively avoids their solid-state self-quenching phenomenon, which, coupling with mesoporous SiO₂ shell, maximumly retains their fluorescence properties. Our method demonstrates a high contrast, selectivity, and sensitivity in fingerprint detection, offering an environmentally friendly and healthy alternative to conventional techniques, and showcasing a facile route to novel solid-state CDs-based fluorescent materials for forensic analysis.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). .

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). .

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). .

This study (June 2022-July 2023) investigates the atmospheric concentrations of carbonaceous species, including organic carbon (OC) and elemental carbon (EC), in PM_2.5 in two major cities in Kazakhstan. Samples were collected from two sites in Almaty (Seifullin and KazNU) and one in Astana. The results showed that Almaty had significantly higher annual average concentrations of OC (10.8 and 10.5 μg/m³) and EC (1.68 and 1.87 μg/m³) compared to Astana (OC: 7.1 μg/m³, EC: 0.61 μg/m³). Both cities exhibited pronounced seasonal variations, with significantly elevated concentrations (1.5-3.4 times for OC, 2.1-4.8 times for EC) during the heating season compared to the non-heating season. This indicates a significant influence of coal and biomass combustion for heating on carbonaceous aerosol concentrations. Both cities' OC/EC ratios varied widely (2.6-39.4), showing strong positive correlations (0.61-0.94) across all seasons except summer, suggesting a common primary emission source. Primary organic carbon dominated OC levels in winter (71-74%), whereas secondary organic carbon contributed significantly to OC concentrations in summer (43-50%). Higher OC-EC concentrations correlated with lower atmospheric visibility values. The OC-EC contributions to the total light extinction coefficient were estimated to be 15.3-15.9% for Almaty and 12.0% for Astana stations.

The production and use of polychlorinated naphthalenes (PCNs) were banned several decades ago, but they continue to be detected due to their persistence in surface environments and ongoing emissions from combustion-related sources. This study presents the first nationwide monitoring data for PCNs in soils collected from 61 sites across South Korea. Industrial sites (mean: 127 pg/g, median: 91.4 pg/g) exhibited higher concentrations of Σ₆₃ PCNs than urban (mean: 53.1 pg/g, median: 50.0 pg/g) and suburban (mean: 52.2 pg/g, median: 23.3 pg/g) sites. Tri- and tetra-CNs were the dominant homologues, with CN-14/24 being the most abundant congeners. The majority of PCN contamination at these sites was attributed to combustion sources and historical emissions from Halowax mixtures. Σ₆₃ PCNs and toxic equivalencies (TEQs) were moderately correlated with the number of companies potentially emitting PCNs, industrial electricity usage, and SO₂ concentrations, indicating a significant influence of anthropogenic sources on PCN contamination. The 95th percentile cancer risks for both adults and children across all sites were within the acceptable range (<10^-6) set by the US EPA. However, the higher risks observed for children underscore the importance of ongoing PCN monitoring. This study provides valuable insights into the spatial distribution and human exposure to PCNs in soils across South Korea. Based on these initial nationwide findings, comprehensive monitoring of PCNs and other dioxin-like compounds in industrial areas is recommended.