Long-Range and Short-Range Structure of Proton-Conducting Y:BaZrO3

Yttrium-doped barium zirconate (BZY) is the most promising candidate for proton-conducting ceramics and has been extensively studied in recent years. The detailed features of the crystal structure, both short-range and long-range, as well as the crystal chemistry driving the doping process, are largely unknown. We use very high resolution X-ray diffraction (HR-XRD) to resolve the crystal structure, which is very slightly tetragonally distorted in BZY, while the local environment around Zr4+ and Y3+ is probed with extended X-ray absorption fine structure (EXAFS), and the symmetry and vibrations are investigated by using Raman spectroscopy. It is found that barium zirconate shows some degree of local deviation from the cubic arystotype even if undoped, which upon substitution by the perceptibly larger Y3+, playing the role of a rigid inclusion, is further increased. This distortion is one limiting factor concerning the Y3+ solubility. The effects are correlated to the proton conduction properties of BZY

Effects of Ginger (Zingiberaceae) on Diabetes Mellitus Induced Changes in the Small Intestine of Rat

Introduction & Objective: Diabetes mellitus is the most common endocrine disorder and causes gastrointestinal complications .The aim of this study was to investigate the effects of ginger on the small intestine of diabetic rats. Materials & Methods: This experimental study was done in the anatomy department of Uremia Medical University in 1385. 24 adult male rats, weighing 250±20 gr were randomly selected and divided into 3 following groups: control, diabetic (induced by 60mg/kg STZ) and treatment groups. The treatment group was given ginger powder (5% of their consumed food weight during day/night period). After 8 weeks, all rats were anaesthetized and their small intestines were removed and measured for their weight and length. For histological assessment, samples from each part of duodenum, jejunum and ileum was fixed in 10% formalin and slides with hematoxilin & eosin staining were prepared. Villi length, crypt depth and muscular layer thickness were assessed by graticule eye piece of light microscope. Statistical analysis, one- way analysis of variance and Tukey’s SPSS software was used for data analysis. Results: The results showed that mean of intestinal length and weight, villi length and muscular layer thickness in all three parts and crypts depth in duodenum and jejunum in diabetic group increased significantly in comparison with control and treatment groups, but there was no significant difference between control and treatment groups. Conclusion: The results of this study demonstrate that ginger as an antioxidant, through decreasing oxidative stress, can prevent pathologic alterations induced by diabetes in small intestine

Experimental and Computational Investigation of Lepidocrocite Anodes for Sodium-Ion Batteries

In this work, we investigated several titanates with lepidocrocite-type structures (general formula AxTi1-yMyO4, with A = Na and M = Li or Mg), having potential utility as anode materials for sodium-ion batteries. First-principles calculations were used to determine key battery metrics, including potential profiles, structural changes during sodiation, and sodium diffusion energy barriers for several compositions, and were compared to experimental results. Site limitations were found to be critical determinants of the gravimetric capacities, which are also affected both by the stacking arrangement of the corrugated layers and the identity of M (Li or Mg). To explain the experimentally observed lattice parameter changes observed as a function of the state of charge, it was necessary to assume the participation of water/solvent during the sodium intercalation process. Sodium diffusion barriers were also found to vary as a function of state of charge and diffusion direction, with a spread of 0.06-1.3 eV at low sodium contents, narrowing to 0.3-0.5 eV at higher sodium contents. Based on these results, strategies for selecting and improving the performance of these electrode materials are suggested

High spatially resolved cation concentration profile at the grain boundaries of Sc-doped BaZrO3_{3}

Recent studies have demonstrated that a higher dopant concentration in the grain boundary region (which includes boundary core and neighboring layers) of acceptor-doped oxides results in a remarkable decrease of grain boundary electrical resistance. In the present work, the spatial distribution of cations in the proton conducting scandium doped barium zirconate is investigated by transmission electron microscopy with high lateral resolution. Cation profiles with a resolution of 0.5 nm obtained using electron energy-loss spectroscopy indicate segregation of a noticeable part of scandium into the grain boundary core. This direct observation is consistent with the measured grain boundary electrical behavior and is interpreted in terms of the space charge model