Naturally occurring intrastrand oxidative cross-link lesions have proven to be a potent source of endogenous DNA damage. Among the variety of lesions that can be formed and have been identified, G[8-5]C damage (in which the C8 atom of a guanine is covalently bonded to the C5 atom of a nearby cytosine belonging to the same strand) occurs with a low incidence yet takes on special importance because of its high mutagenicity. Hybrid Car-Parrinello molecular dynamics simulations, rooted in density functional theory and coupled to molecular mechanics, have been performed to shed light on the cyclization process. The activation free energy of the reacting subsystem embedded in a solvated dodecamer is estimated to be ∼12.4 kcal/mol, which is ∼3 kcal/mol higher than the value for the prototypical G[8-5m]T lesion inferred employing the same theoretical framework [Garrec, J., Patel, C., Rothlisberger, U., and Dumont, E. (2012) J. Am. Chem. Soc.134, 2111-2119]. This study also situates the G[8-5m]mC lesion at an intermediate activation free energy (∼10.5 kcal/mol). The order of reactivity in DNA (T(•) > mC(•) > C(•)) is reversed compared to that in the reacting subsystems in the gas phase (C(•) > mC(•) > T(•)), stressing the crucial role of the solvated B-helix environment. The results of our simulations also characterize a more severe distortion for G[8-5]C than for methylene-bridged intrastrand cross-links.
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Sci Adv
January 2025
Department of Convergence IT Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Pohang 37673, Republic of Korea.
Pressure and temperature sensing simultaneously and independently is crucial for creating electronic skin that replicates complex sensory functions of human skin. Thin-film transistor (TFT) arrays with sensors have enabled cross-talk-free spatial sensing. However, the thermal dependence of charge transport in semiconductors has resulted in interference between thermal and pressure stimuli.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
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Department of Electrical & Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130.
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View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
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Research Institute of the, McGill University Health Centre, Montreal, QC, Canada.
The increasing shift from cannabis smoking to cannabis vaping is largely driven by the perception that vaping to form an aerosol represents a safer alternative to smoking and is a form of consumption appealing to youth. Herein, we compared the chemical composition and receptor-mediated activity of cannabis smoke extract (CaSE) to cannabis vaping extract (CaVE) along with the biological response in human bronchial epithelial cells. Chemical analysis using HPLC and GC/MS revealed that cannabis vaping aerosol contained fewer toxicants than smoke; CaSE and CaVE contained teratogens, carcinogens, and respiratory toxicants.
View Article and Find Full Text PDFChem Asian J
January 2025
University of Queensland, School of Chemical Engineering, AUSTRALIA.
The activation mechanism of Li-rich cathode has been discussed for many years, yet there is still debate on different theories. Potassium doping can assist the investigation on activation mechanism through its unique function in terms of blocking TM migration during activation. K-doping works by occupying Li sites even after Li has been extracted, increasing stability by blocking transition metals from migrating into these sites, which can help us distinguish the pathway of activation.
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