Dynamic Evolution of S0_0∼\simS3_3 at the Oxygen Evolving Complex with the Spin Marker under the Photoelectric Polarization

Water oxidation in the oxygen evolving complex (OEC) of the photosystem II is catalyzed by the core cluster CaMn$_4$O$_5$ which was projected to experience five intermediate states S($\rm_i$) in the Kok's cycle since 1970's. However, the detailed dynamics of state evolutions still remains unclear, albeit with the general fact that the process is initiated by the transfer of photoelectrons with the steady electron donors of the water molecules. Based on density functional simulations, we find that the spin flips of Manganese atoms between the consecutive states in the electric polarization field can be used as a marker to uncover the intricate dynamic evolutions and the underlying dynamics. The dynamic electron and proton transfers and water insertion and dissociation are traced to reveal the evolution pathways of S$_0$$\sim$S$_3$ with commensurate spin flips towards the exact spin configuration of the next state. In particular, the various water insertions and dissociations at coordination sites of the S$_2$ open and closed cubane isomers are predicted with constraints on the necessary spin flips. Our study lays a solid ground for getting through the whole Kok's cycle via the pending S$_4$ state that is crucial for dioxygen generation.Comment: 8 pages, 5 figure

Relativistic symmetry breaking in light kaonic nuclei

As the experimental data from kaonic atoms and $K^{-}N$ scatterings imply that the $K^{-}$-nucleon interaction is strongly attractive at saturation density, there is a possibility to form $K^{-}$-nuclear bound states or kaonic nuclei. In this work, we investigate the ground-state properties of the light kaonic nuclei with the relativistic mean field theory. It is found that the strong attraction between $K^{-}$ and nucleons reshapes the scalar and vector meson fields, leading to the remarkable enhancement of the nuclear density in the interior of light kaonic nuclei and the manifest shift of the single-nucleon energy spectra and magic numbers therein. As a consequence, the pseudospin symmetry is shown to be violated together with enlarged spin-orbit splittings in these kaonic nuclei.Comment: 15 pages, 7 figure

Adiponectin protects against paraquat-induced lung injury by attenuating oxidative/nitrative stress.

The specific mechanisms underlying paraquat (PQ)-induced lung injury remain unknown, which limits understanding of its cytotoxic potential. Although oxidative stress has been established as an important mechanism underlying PQ toxicity, multiple antioxidants have proven ineffective in attenuating the deleterious effects of PQ. Adiponectin, which shows anti-oxidative and antinitrative effects, may have the potential to reduce PQ-mediated injury. The present study determined the protective action of globular domain adiponectin (gAd) on PQ-induced lung injury, and attempted to elucidate the underlying mechanism or mechanisms of action. BALB/c mice were administered PQ, with and without 12 or 36 h of gAd pre-treatment. The pulmonary oxidative/nitrative status was assessed by measuring pulmonary O2(•-), superoxide dismutase (SOD), malondialdehyde (MDA), nitric oxide (NO) and 8-hydroxy-2-dydeoxy guanosine (8-OHdG) production, and blood 3-Nitrotyrosine (3-NT). At a dose of 20 mg/kg, PQ markedly increased O2(•-), SOD, MDA, NO and 8-OHdG production 3 h post-administration, but did not significantly increase 3-NT levels until 12 h. gAd inhibited these changes in a dose-dependent manner, via transient activation of MDA, followed by attenuation of MDA formation from 6 h onwards. Histological analysis demonstrated that gAd decreased interstitial edema and inflammatory cell infiltration. These results suggest that gAd protects against PQ-induced lung injury by mitigating oxidative/nitrative stress. Furthermore, gAd may be a potential therapeutic agent for PQ-induced lung injury, and further pharmacological studies are therefore warranted