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Organophosphorus flame retardants (PFRs) are a class of flame retardants and environmental pollutants with various biological effects. Recentstudies have evidenced activation of some PFRs by human CYP enzymes (including CYP2E1) for genotoxic effects. However, the activity of CYPs in fish species toward PFR metabolism remains unclear. This study was aimed on comparing the metabolism of triphenyl phosphate (TPHP) and 4-OH-TPHP in human, rat, and common carp, and the involvement of human CYP2E1 and its orthologs in the metabolism, by using fomepizole (4-MP, CYP2E1 inhibitor) as a modulator, in silico molecular docking and dynamics analyses. The rate of TPHP metabolism was apparently faster with human and rat, microsomes than with fish microsomes, the major metabolites were phosphodiester and hydroxylated phosphate, with 30-80 % of TPHP forming unidentified metabolites in the system of each species. 4-OH-TPHP was readily metabolized by both human and rat microsomes, whereas it was hardly metabolized in carp assays. Meanwhile, with 4-MP the transformation of TPHP to 4-OH-TPHP was enhanced in the human/rat systems while suppressed in the carp system. Moreover, the formation of unidentified metabolites in human and rat systems was mostly inhibited by 4-MP. Through molecular dynamics analysis TPHP and its primary metabolites showed high affinity for human and rat CYP2E1, as well as the carp ortholog (CYP2G1-like enzyme), however, the 4-OH-TPHP bond to the latter was too far from the heme to permit a biochemical reaction. This study suggests that the metabolism/activation of TPHP might be favored in mammals rather than carp, a fish species., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Both tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF) are the first-line treatments for chronic hepatitis B (CHB). We have showed switching from TDF to TAF for 96 weeks resulted in further alanine aminotransferase (ALT) improvement, but data remain lacking on the long-term benefits of TDF switching to TAF on hepatic fibrosis., Aim: To assess the benefits of TDF switching to TAF for 3 years on ALT, aspartate aminotransferase (AST), and hepatic fibrosis improvement in patients with CHB., Methods: A single center retrospective study on 53 patients with CHB who were initially treated with TDF, then switched to TAF to determine dynamic patterns of ALT, AST, AST to platelet ratio index (APRI), fibrosis-4 (FIB-4) scores, and shear wave elastography (SWE) reading improvement at switching week 144, and the associated factors., Results: The mean age was 55 (28-80); 45.3%, males; 15.1%, clinical cirrhosis; mean baseline ALT, 24.8; AST, 25.7 U/L; APRI, 0.37; and FIB-4, 1.66. After 144 weeks TDF switching to TAF, mean ALT and AST were reduced to 19.7 and 21, respectively. From baseline to switching week 144, the rates of ALT and AST < 35 (male)/25 (female) and < 30 (male)/19 (female) were persistently increased; hepatic fibrosis was also improved by APRI < 0.5, from 79.2% to 96.2%; FIB-4 < 1.45, from 52.8% to 58.5%, respectively; mean APRI was reduced to 0.27; FIB-4, to 1.38; and mean SWE reading, from 7.05 to 6.30 kPa after a mean of 109 weeks switching. The renal function was stable and the frequency of patients with glomerular filtration rate > 60 mL/min was increased from 86.5% at baseline to 88.2% at switching week 144., Conclusion: Our data confirmed that switching from TDF to TAF for 3 years results in not only persistent ALT/AST improvement, but also hepatic fibrosis improvement by APRI, FIB-4 scores, as well as SWE reading, the important clinical benefits of long-term hepatitis B virus antiviral treatment with TAF., Competing Interests: Conflict-of-interest statement: Hu KQ is on the Speaker Bureau for Gilead. Huynh T, Bui DM, and Zhou TX reported no conflict of interests related to this study., (©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.)

Persistent organic pollutants pose a great threat to amphibian populations, but information on the bioaccumulation of contaminants in amphibians remains scarce. To examine the tissue distribution and maternal transfer of organic halogenated pollutants (OHPs) in frogs, seven types of tissues from black-spotted frog (muscle, liver, kidney, stomach, intestine, heart, and egg) were collected from an e-waste-polluted area in South China. Among the seven frog tissues, median total OHP concentrations of 2.3 to 9.7 μg/g lipid weight were found (in 31 polychlorinated biphenyl [PCB] individuals and 15 polybrominated diphenyl ether [PBDE], dechlorane plus [syn-DP and anti-DP], bexabromobenzene [HBB], polybrominated biphenyl] PBB153 and -209], and decabromodiphenyl ethane [DBDPE] individuals). Sex-specific differences in contaminant concentration and compound compositions were observed among the frog tissues, and eggs had a significantly higher contaminant burden on the whole body of female frogs. In addition, a significant sex difference in the concentration ratios of other tissues to the liver was observed in most tissues except for muscle. These results suggest that egg production may involve the mobilization of other maternal tissues besides muscle, which resulted in the sex-specific distribution. Different parental tissues had similar maternal transfer mechanisms; factors other than lipophilicity (e.g., molecular size and proteinophilic characteristics) could influence the maternal transfer of OHPs in frogs. Environ Toxicol Chem 2024;43:1557-1568. © 2024 SETAC., (© 2024 SETAC.)

The attributes of good solubility and the redox-neutral nature of molten salt fluxes enable them to be useful for the synthesis of novel crystalline actinide compounds. In this work, a flux growth method under an inert atmosphere is proposed to explore the valence diversity of uranium, and a series of five uranium silicate structures, [K 3 Cl][(U VI O 2 )(Si 4 O 10 )] ( 1 ), Cs 3 [(U V O 2 )(Si 4 O 10 )] ( 2 ), K 2 [U IV (Si 2 O 7 )] ( 3 ), K 8 [(U VI O 2 )(U V O 2 ) 2 (Si 8 O 22 )] ( 4 ), and Cs 6 [U IV (U V O) 2 (Si 12 O 32 )] ( 5 ), were synthesized using different metal halide salt and feeding U/Si ratios. Crystal structure analysis reveals that the utilization of argon atmosphere that helps to avoid possible oxidation of low-valence uranium generates a variety of oxidation states of uranium including U(VI), U(V), U(IV), mixed-valence U(V) and U(VI), and mixed-valence U(IV) and U(V). Characterization of physicochemical properties of representative compounds shows that all these uranium silicate compounds have bandgaps among the range of 2.0-3.4 eV, and mixed-valence uranium silicate compounds have relatively narrower bandgaps. Density functional theory calculations on formation enthalpies, lattice energies, and bandgaps of all five compounds were also performed to provide more structural information about these uranium silicates. This work enriches the library of variable-valence uranium silicate compounds and provides a feasible way to produce novel actinide compounds with intriguing properties through the flux growth method that might show potential application in relevant fields such as storage media for nuclear waste.

Dilanthanide complexes with one-electron delocalization are important targets for understanding the specific 4f/5d-bonding feature in lanthanide chemistry. Here, we report an isolable azide-bridged dicerium complex 3 [{(Trapen TMS )Ce} 2 (μ-N 3 )] • [Trapen = tris (2-aminobenzyl)amine; TMS = SiMe 3 ], which is synthesized by the reaction of tripodal ligand-supported (Trapen TMS )Ce IV Cl complex 2 with NaN 3 . The structure and bonding nature of 3 are fully characterized by X-ray crystal diffraction analysis, electron paramagnetic resonance (EPR), magnetic measurement, cyclic voltammetry, X-ray absorption spectroscopy, and quantum-theoretical studies. Complex 3 presents a trans-bent central Ce-N 3 -Ce unit with a single electron of two mixed-valent Ce atoms. The unique low-temperature (2 K) anisotropic EPR signals [ g = 1.135, 2.003, and 3.034] of 3 indicate that its spin density is distributed on the central Ce-N 3 -Ce unit with marked electron delocalization. Quantum chemical analyses show strong 4f/5d orbital mixing in the singly occupied molecular orbital of 3 , which allows for the unpaired electron to extend throughout the cerium-azide-cerium unit via a multicentered one-electron (Ce-N 3 -Ce) interaction. This work extends the family of mixed-valent dilanthanide complexes and provides a paradigm for understanding the bonding motif of ligand-bridged dilanthanide complexes.