Revealing the Interaction of Charge Carrier-Phonon Coupling by Quantification of Electronic Properties at the SrTiO3/TiO2 Heterointerface.

Oxide heterointerfaces with high carrier density can interact strongly with the lattice phonons, generating considerable plasmon-phonon coupling and thereby perturbing the fascinating optical and electronic properties, such as two-dimensional electron gas, ferromagnetism, and superconductivity. Here we use infrared-spectroscopic nanoimaging based on scattering-type scanning near-field optical microscopy (s-SNOM) to quantify the interaction of electron-phonon coupling and the spatial distribution of local charge carriers at the SrTiO3/TiO2 interface. We found an increased high-frequency dielectric constant (ε∞ = 7.1-9.0) and charge carrier density (n = 6.5 × 1019 to 1.5 × 1020 cm-3) near the heterointerface. Moreover, quantitative information between the charge carrier density and extension thickness across the heterointerface has been extracted by monochromatic near-field imaging. A direct evaluation of the relationship between the thickness and the interaction of charge carrier-phonon coupling of the heterointerface would provide valuable information for the development of oxide-based electronic devices.

The dietary inflammatory index and metabolic health of population-based Chinese elderly.

BACKGROUND AND OBJECTIVES: This study evaluated the relationship between dietary inflammatory index (DII) and metabolic health in the Chinese elderly. METHODS AND STUDY DESIGN: A total of 6,730 participants from the "Community-based Cardiovascular and Health Promotion Study" (CoCHPS) cohort were included in this study. The DII scores were acquired using a validated 125-item food-frequency questionnaire (FFQ) (ranged -5.84 to 3.90). The correlation of DII with metabolic health indexes was evaluated with logistic regression and multivariable cox regression using SPSS and R software. RESULTS: Compared with low DII scores, subjects in the highest DII score quartiles had higher odds of metabolic dysfunction (OR=1.36, 95% CI: 1.07-1.68, p trend=0.023). In the subgroup analyses, the effect of a pro-inflammatory diet on metabolic dysfunction was particularly evident among people with hyperglycaemia (HR=1.58, 95% CI: 1.35-2.14), hypertension (HR=1.48, 95% CI: 1.07-2.09), dyslipidemia (HR=1.45, 95% CI: 1.24-1.87), abdominal obesity (HR=2.16, 95% CI: 1.57-2.96), and ≥60 years old (HR=1.32, 95% CI: 1.04-1.56) or who were women (HR=1.35, 95% CI: 1.08-1.67). CONCLUSIONS: DII score was associated with metabolic health. Further studies are needed to deepen our understanding of dietary parameters and different populations.

Facilitating the Deprotonation of OH to O through Fe4+ -Induced States in Perovskite LaNiO3 Enables a Fast Oxygen Evolution Reaction.

Aliovalent doping is widely adopted to tune the electronic structure of transition-metal oxides for design of low-cost, active electrocatalysts. Here, using single-crystalline thin films as model electrocatalysts, the structure-activity relationship of Fe states doping in perovskite LaNiO3 for oxygen evolution reaction (OER) is studied. Fe4+ state is found to be crucial for enhancing the OER activity of LaNiO3 , dramatically increasing the activity by six times, while Fe3+ has negligible effect. Spectroscopic studies and DFT calculations indicate Fe4+ states enhance the degree of Ni/Fe 3d and O 2p hybridization, and meanwhile produce down-shift of the unoccupied density of states towards lower energies. Such electronic features reduce the energy barrier for interfacial electron transfer for water oxidization by 0.2 eV. Further theoretical calculations and H/D isotope experiments reveal the electronic states associated with Fe4+ -O2- -Ni3+ configuration accelerate the deprotonation of *OH to *O (rate-determining step), and thus facilitate fast OER kinetics.