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  1. In this paper, we investigate the dynamical behavior for a hybrid non-autonomous predator–prey system with Holling Type II functional response, impulsive effects and generalist predator on time scales, where our proposed model commutes between a continuous-time dynamical system and discrete-time dynamical system. By using comparison theorems, we first study the permanence results of the proposed model. Also, we established the uniformly asymptotic stability for the almost periodic solution of the proposed model. Finally, in the last section, we provide some examples with numerical simulation.
    Free, publicly-accessible full text available January 1, 2024
  2. Abstract We evaluate the allowed $\beta^-$-decay properties of nuclei with $Z = 8$–$15$ systematically under the framework of the nuclear shell model using the valence space Hamiltonians derived from modern ab initio methods, such as in-medium similarity renormalization group and coupled-cluster theory. For comparison we also show results obtained with fitted interaction derived from chiral effective field theory and phenomenological universal $sd$-shell Hamiltonian version B interaction. We have performed calculations for O $\rightarrow$ F, F $\rightarrow$ Ne, Ne $\rightarrow$ Na, Na $\rightarrow$ Mg, Mg $\rightarrow$ Al, Al $\rightarrow$ Si, Si $\rightarrow$ P, and P $\rightarrow$ S transitions. Theoretical results for $B(GT)$, $\log ft$ values, and half-lives are discussed and compared with the available experimental data.
  3. Of particular interest in radiation-induced charge transfer processes in DNA is the extent of hole localization immediately after ionization and subsequent relaxation. To address this, we considered double stranded oligomers containing guanine (G) and 8-oxoguanine (8OG), i.e. , ds(5′-GGG-3′) and ds(5′-G8OGG-3′) in B-DNA conformation. Using DFT, we calculated a variety of properties, viz. , vertical and adiabatic ionization potentials, spin density distributions in oxidized stacks, solvent and solute reorganization energies and one-electron oxidation potential ( E 0 ) in the aqueous phase. Calculations for the vertical state of the -GGG- cation radical showed that the spin was found mainly (67%) on the middle G. However, upon relaxation to the adiabatic -GGG- cation radical, the spin localized (96%) on the 5′-G, as observed in experiments. Hole localizations on the middle G and 3′-G were higher in energy by 0.5 kcal mol −1 and 0.4 kcal mol −1 , respectively, than that of 5′-G. In the -G8OGG- cation radical, the spin localized only on the 8OG in both vertical and adiabatic states. The calculated vertical ionization potentials of -GGG- and -G8OGG- stacks were found to be lower than that of the vertical ionization potential of a single G in DNA. The calculatedmore »E 0 values of -GGG- and -G8OGG- stacks are 1.15 and 0.90 V, respectively, which owing to stacking effects are substantially lower than the corresponding experimental E 0 values of their monomers (1.49 and 1.18 V, respectively). SOMO to HOMO level switching is observed in these oxidized stacks. Consequently, our calculations predict that local double oxidations in DNA will form triplet diradical states, which are especially significant for high LET radiations.« less
  4. This review article provides a concise overview of electron involvement in DNA radiation damage. The review begins with the various states of radiation-produced electrons: Secondary electrons (SE), low energy electrons (LEE), electrons at near zero kinetic energy in water (quasi-free electrons, (e−qf)) electrons in the process of solvation in water (presolvated electrons, e−pre), and fully solvated electrons (e−aq). A current summary of the structure of e−aq, and its reactions with DNA-model systems is presented. Theoretical works on reduction potentials of DNA-bases were found to be in agreement with experiments. This review points out the proposed role of LEE-induced frank DNA-strand breaks in ion-beam irradiated DNA. The final section presents radiation-produced electron-mediated site-specific formation of oxidative neutral aminyl radicals from azidonucleosides and the evidence of radiosensitization provided by these aminyl radicals in azidonucleoside-incorporated breast cancer cells.