Ferroelectric Properties of CuFe2O4, BaFe2O4, Ba0.2La0.8Fe2O4 Nanoparticles

In this article, we report ferroelectric properties of copper ferrite CuFe2O4 nanoparticles (CFN), Barium ferrite nanoparticles BaFe2O4 (BFN) and La substituted barium ferrite Ba0.2La0.8Fe2O4 (BLFN) nanoparticles synthesized via hydrothermal technique. The X-Ray diffraction for the synthesized particles reflects the cubic phase formation for CuFe2O4, orthorhombic phase structure for the BaFe2O4 and cubic formation of Ba0.2La0.8Fe2O4 (BLFN). The structural parameters such as crystallite size and micro-strain are computed from XRD and Williamson-Hall(W-H) analysis. The polarization- electric field (P-E) loop studies gave information about the ferroelectric nature of the synthesized samples. It was noticed that the CFN particle has a lossy dielectric nature whereas BFN, BLFN samples exhibit a multiferroic nature

Structural Insights from Binding Poses of CCR2 and CCR5 with Clinically Important Antagonists: A Combined In Silico Study

Chemokine receptors are G protein-coupled receptors that contain seven transmembrane domains. In particular, CCR2 and CCR5 and their ligands have been implicated in the pathophysiology of a number of diseases, including rheumatoid arthritis and multiple sclerosis. Based on their roles in disease, they have been attractive targets for the pharmaceutical industry, and furthermore, targeting both CCR2 and CCR5 can be a useful strategy. Owing to the importance of these receptors, information regarding the binding site is of prime importance. Structural studies have been hampered due to the lack of X-ray crystal structures, and templates with close homologs for comparative modeling. Most of the previous models were based on the bovine rhodopsin and β2-adrenergic receptor. In this study, based on a closer homolog with higher resolution (CXCR4, PDB code: 3ODU 2.5 Å), we constructed three-dimensional models. The main aim of this study was to provide relevant information on binding sites of these receptors. Molecular dynamics simulation was done to refine the homology models and PROCHECK results indicated that the models were reasonable. Here, binding poses were checked with some established inhibitors of high pharmaceutical importance against the modeled receptors. Analysis of interaction modes gave an integrated interpretation with detailed structural information. The binding poses confirmed that the acidic residues Glu291 (CCR2) and Glu283 (CCR5) are important, and we also found some additional residues. Comparisons of binding sites of CCR2/CCR5 were done sequentially and also by docking a potent dual antagonist. Our results can be a starting point for further structure-based drug design

Barium titanate microspheres by low temperature hydrothermal method: studies on structural, morphological, and optical properties

The barium titanate (BT) microspheres were synthesized via the low temperature hydrothermal technique. The X-ray diffraction pattern confirmed the formation of cubic perovskite structure of the material. The average crystallite size (Dp) was found to be of 21 nm using the Scherrer method. The Williamson–Hall plot was drawn for evaluating the micro-strain and crystallite diameter. The relation between micro-strain (ε) and Dp was illustrated as a function of diffraction angle (2θ). The morphology was analyzed by field emission and transmission electron microscope. The results expressed the formation of microspheres. In addition to these, the optical bandgap (Eop) and maximum absorption wavelength (λm) were achieved to be of 3.23 eV and 340 nm, respectively. The presence of metal oxide bonds (M-O) was observed which in turn attributes the formation of cubic structure

Tropical stratopause features - Rayleigh lidar observations over Gadanki (13.5°N, 79.2°E), India

International audienceThe characteristics of straggle feature "Double stratopause" observed in temperature profiles using Rayleigh lidar at National Atmospheric Research Laboratary (NARL), Gadanki (13.5°N, 79.2°E), India is presented in this paper. Out of 216 nights of observations made during March 1998-April 2001, the double stratopause is observed for 122 days (~56.5 %). The two stratopause peaks are found to be separated by ~2-10 km. Applying third order polynomial fit to the mean temperature profiles provided the quantification on peak and trough stratopause heights and temperatures. The monthly percentages of occurrence of double stratopause show peaks in June and September with weak seasonal dependence. The splitting in stratopause is considered in terms of gravity wave breaking due to Kelvin Helmholtz instability. There appeared to be a sudden increase in gravity wave potential energy in stratopause region during the presence of its split and also observed a maximum speed in wind, derived from NCEP reanalysis data