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Full-Text Articles in Physical Sciences and Mathematics
Four Novel Co-Precipitation Procedures For The Synthesis Of Lanthanum-Strontium Manganites, Vuk Uskoković, Miha Drofenik
Four Novel Co-Precipitation Procedures For The Synthesis Of Lanthanum-Strontium Manganites, Vuk Uskoković, Miha Drofenik
Pharmacy Faculty Articles and Research
Lanthanum-strontium manganites were synthesized using co-precipitation method with a reverse micellar microemulsion. Either oxalic acid, sodium hydroxide or tetramethylammonium hydroxide was used for the precipitation of precursor cations in a form that was subsequently calcined under various conditions in order to obtain perovskite manganite phase. Correlations between the properties of the synthesized powder and the calcination conditions have been put forth. The properties of the microemulsion-assisted synthesized material were compared with the samples prepared by following the supposedly similar chemical recombinations in bulk solutions, with an aim to challenge the fact that microemulsions in general have only templating effects on …
Coupling Coherence Distinguishes Structure Sensitivity In Protein Electron Transfer, Tatiana Prytkova, Igor V. Kurnikov, David Beratan
Coupling Coherence Distinguishes Structure Sensitivity In Protein Electron Transfer, Tatiana Prytkova, Igor V. Kurnikov, David Beratan
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Quantum mechanical analysis of electron tunneling in nine thermally fluctuating cytochrome b562 derivatives reveals two distinct protein-mediated coupling limits. A structure-insensitive regime arises for redox partners coupled through dynamically averaged multiple-coupling pathways (in seven of the nine derivatives) where heme-edge coupling leads to the multiple-pathway regime. A structure-dependent limit governs redox partners coupled through a dominant pathway (in two of the nine derivatives) where axial-ligand coupling generates the single-pathway limit and slower rates. This two-regime paradigm provides a unified description of electron transfer rates in 26 ruthenium-modified heme and blue-copper proteins, as well as in numerous photosynthetic proteins.
Flavin Charge Transfer Transitions Assist Dna Photolyase Electron Transfer, Spiros S. Skourtis, Tatiana Prytkova, David Beratan
Flavin Charge Transfer Transitions Assist Dna Photolyase Electron Transfer, Spiros S. Skourtis, Tatiana Prytkova, David Beratan
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
This contribution describes molecular dynamics, semi-empirical and ab-initio studies of the primary photo-induced electron transfer reaction in DNA photolyase. DNA photolyases are FADH−-containing proteins that repair UV-damaged DNA by photo-induced electron transfer. A DNA photolyase recognizes and binds to cyclobutatne pyrimidine dimer lesions of DNA. The protein repairs a bound lesion by transferring an electron to the lesion from FADH−, upon photo-excitation of FADH− with 350–450 nm light. We compute the lowest singlet excited states of FADH− in DNA photolyase using INDO/S configuration interaction, time-dependent density-functional, and time-dependent Hartree-Fock methods. The calculations identify the lowest singlet excited state of FADH− …