Non-Fermi-liquid behavior in cubic phase BaRuO3_{3}: A dynamical mean-field study

Motivated by the recently synthesized cubic phase BaRuO$_{3}$ under high pressure and high temperature, a thorough study has been conducted on its temperature-dependent electronic properties by using the state-of-the-art \textit{ab inito} computing framework of density functional theory combined with dynamical mean-field theory. At ambient condition the cubic phase BaRuO$_{3}$ should be a weakly correlated Hund's metal with local magnetic moment. The spin-spin correlation function and local magnetic susceptibility can be well described by the Curie-Weiss law over a wide temperature range. The calculated low-frequency self-energy functions of Ru-4d states apparently deviate from the behaviors predicted by Landau Fermi-liquid theory. Beyond that, the low-frequency optical conductivity can be fitted to a power-law $\Re\sigma(\omega) \sim \omega^{-0.98}$, which further confirms the Non-Fermi-liquid metallic state.Comment: 6 pages, 4 figure

Differential responses of osteoblasts and macrophages upon Staphylococcus aureus infection

Background Staphylococcus aureus (S. aureus) is one of the primary causes of bone infections which are often chronic and difficult to eradicate. Bacteria like S. aureus may survive upon internalization in cells and may be responsible for chronic and recurrent infections. In this study, we compared the responses of a phagocytic cell (i.e. macrophage) to a non-phagocytic cell (i.e. osteoblast) upon S. aureus internalization. Results We found that upon internalization, S. aureus could survive for up to 5 and 7 days within macrophages and osteoblasts, respectively. Significantly more S. aureus was internalized in macrophages compared to osteoblasts and a significantly higher (100 fold) level of live intracellular S. aureus was detected in macrophages compared to osteoblasts. However, the percentage of S. aureus survival after infection was significantly lower in macrophages compared to osteoblasts at post-infection days 1–6. Interestingly, macrophages had relatively lower viability in shorter infection time periods (i.e. 0.5-4 h; significant at 2 h) but higher viability in longer infection time periods (i.e. 6–8 h; significant at 8 h) compared to osteoblasts. In addition, S. aureusinfection led to significant changes in reactive oxygen species production in both macrophages and osteoblasts. Moreover, infected osteoblasts had significantly lower alkaline phosphatase activity at post-infection day 7 and infected macrophages had higher phagocytosis activity compared to non-infected cells. Conclusions S. aureus was found to internalize and survive within osteoblasts and macrophages and led to differential responses between osteoblasts and macrophages. These findings may assist in evaluation of the pathogenesis of chronic and recurrent infections which may be related to the intracellular persistence of bacteria within host cells

Non-Fermi-liquid behavior in cubic phase BaRuO₃: A dynamical mean-field study

Motivated by the recently synthesized cubic phase BaRuO₃ under high pressure and high temperature, a thorough study has been conducted on its temperature-dependent electronic properties by using the state-of-the-art ab initio computing framework of density-functional theory combined with dynamical mean-field theory. At ambient condition the cubic phase BaRuO₃ should be a correlated Hund's metal with frozen spin magnetic moment. The spin-spin correlation function and local magnetic susceptibility can be well described by the Curie-Weiss law over a wide temperature range. The calculated low-frequency self-energy functions of Ru 4d states apparently deviate from the behaviors predicted by Landau Fermi-liquid theory. Beyond that, the low-frequency optical conductivity can be fitted to a power law ℜσ(ω)∼ω−0.98, which further confirms the non-Fermi-liquid metallic stat

Influences of Surface Substitutional Ti Atom on Hydrogen Adsorption, Dissociation, and Diffusion Behaviors on the α‑U(001) Surface

The hydrogen adsorption, dissociation, and diffusion behaviors on both clean and Ti-doped α-U(001) surfaces are systematically studied with density functional theory method. Through detailed potential energy surface calculations, we find that the dissociation at the bridge sites is energetically more favorable, where the H₂ molecule dissociates without any energy barrier and the dissociated hydrogen atoms move into two neighboring 3-fold sites. Once a substitutional Ti atom exists on the α-U(001) surface, the hydrogen molecule similarly dissociates without any energy barriers. However, the diffusion of the dissociated hydrogen atoms is dramatically changed after introduction of a surface substitutional Ti atom. The into-bulk penetration of a hydrogen atom through a defect-free surface is endothermic and needs to overcome an energy barrier of 0.8–0.9 eV. In contrast, the penetration to the subsurface sites near the doped Ti atom is exothermic, and the activation barrier decreases by 0.3–0.4 eV. Our results indicate that surface doped titanium atoms in the outermost layer may behave like hydrogen trapping sites for α-U

New Insights into the Crystal Structures of Plutonium Hydrides from First-Principles Calculations

One of the important research contents on hydrogen corrosion of plutonium is the determination of the complex crystal structures of plutonium hydrides and the bonding interactions between plutonium and hydrogen. However, it is very difficult to carry out the structural characterization of plutonium hydrides because of their high activity, high toxicity, and radioactivity. In this work, the crystal structures, lattice vibrations, and bonding properties of plutonium hydrides under ambient pressure are investigated by means of the density functional theory + <i>U</i> approach. Results show that PuH₃ exhibits many competition phase structures. After considering spin polarization, strong correlation (<i>U</i>), and spin–orbit coupling effects on the total energy and lattice dynamics stability, it is found that PuH₃ at ambient pressure is more likely to be hexagonal <i>P</i>6₃<i>cm</i> or trigonal <i>P</i>3<i>c</i>1 structure, instead of the usual supposed structures of hexagonal <i>P</i>6₃/<i>mmc</i> (LaF₃-type) and face-centered cubic (BiF₃-type). The calculated electronic structures clearly indicate that <i>P</i>6₃<i>cm</i> (<i>P</i>3<i>c</i>1) PuH₃ is a semiconductor with a small band gap about 0.87 eV (0.85 eV). The Pu–H bonds in Pu hydrides are dominated by the ionic interactions