Comparative study of the electrical and dielectric properties of PVA–PEG–Al2O3–MI (M=Na,K, Ag) complex polymer electrolytes

Plasticized nanocomposite polymer electrolytes (PNCPEs) based on poly(vinyl alcohol) (PVA)–MI (M=Na, K, Ag) dispersed with nanofillers Al₂O₃ and plasticized with poly(ethylene glycol) (PEG) have been prepared by solution cast technique. The structural properties of the samples have been characterized using various experimental techniques such as XRD, DSC, FTIR and B-G spectroscopy. The ionic conductivity and dielectric constant of the samples have been estimated using a LCZ meter in a wide temperature range, i.e. from 30 to 170 °C. It has been observed that the presence of water molecules in polymer electrolytes significantly affects the mobility of ionic species. The temperature dependent ionic conductivity shows the Arrhenius type behavior separated in three distinct regions. The ionic transference number for all PNCPE samples is found to be ≈1, which strongly suggests their ionic nature.     

Some aspects of metal-support strong interactions in Rh/Al2O3 catalyst under oxidising and reducing conditions

The aim of the Letter is to elucidate the nature of metal-support interaction in the 2 wt% Rh/Al₂O₃ catalyst obtained by annealing Rh–O–Al xerogel at 1113 K in air.XPS, HRTEM, and XRD results reveal that during the Rh–O–Al xerogel annealing in air, rhodium incorporates into forming alumina, which results mostly in Rh⁴⁺/δ-Al₂O₃ solid solution formation.However, in the course of the catalyst reduction at 773 with H₂ and at 823 K with CH₄ the Rh⁴⁺/δ-Al₂O₃ solid solution transforms into Rh–Al alloy. The islands of rhodium form on the surface of the Rh–Al alloy nanocrystallites if the reduction is slow enough.     

Impact of cannibalism on dynamics of a structured predator–prey system

Cannibalism, as a behavioral trait, is prevalent in many species. To have better understanding of their dynamics, we investigate a structured predator-prey system with predator cannibalism, where the prey population follows the logistic growth in the absence of the predator. We study the effects of the cannibalism attack rate and the corresponding benefit rate of cannibals on the model dynamics. Complex phenomena, including the bistability, the existences of two positive equilibria and stable/unstable periodic solutions, are found. We define quantities with clear biological meanings, and establish conditions determining the local and global dynamics of the model based on these quantities. Our results show that, under certain conditions, the final states of the populations depend on not only the related model parameters but also the initial conditions of the solutions.     

Defect centres and thermoluminescence in SrS:Bi phosphor

Thermoluminescence (TL) and electron spin resonance studies have been carried out on SrS:Bi phosphor. The TL glow curve is broad and indicates a dominant peak at 120 ^°C with two additional peaks, not clearly resolved, appearing as shoulders at around 180 and 250 ^°C. Two defect centres are observed at room temperature. One of them is characterized by an isotropic g-value 2.0034 and is assigned to an F⁺ centre. Step annealing measurements indicate a possible association between the F⁺ centre and the three TL peaks.     

Spectrochemical analysis of powder using 355 nm Nd-YAG laser-induced low-pressure plasma

The applicability of spectrochemical analysis of minute amounts of powder samples was investigated using an ultraviolet Nd-YAG laser (355 nm) and low-pressure ambient air. A large variety of chemical powder samples of different composition were employed in the experiment. These included a mixture of copper(II) sulfate pentahydrate, zinc sulfide, and chromium(III) sulfate n-hydrate powders, baby powder, cosmetic powders, gold films, zinc supplement tablet, and muds and soils from different areas. The powder samples were prepared by pulverizing the original samples to an average size of around 30 μm in order to trap them in the tiny micro holes created on the surface of the quartz subtarget. It was demonstrated that in all cases studied, good quality spectra were obtained with low background, free from undesirable contamination by the subtarget elements and featuring ppm sensitivity. A further measurement revealed a linear calibration curve with zero intercept. These results clearly show the potential application of this technique for practical qualitative and quantitative spectrochemical analysis of powder samples in various fields of study and investigation.     

Dynamic conformational ensembles regulate casein kinase-1 isoforms: Insights from molecular dynamics and molecular docking studies

Casein kinase-1 (CK1) isoforms actively participate in the down-regulation of canonical Wnt signaling pathway; however recent studies have shown their active roles in oncogenesis of various tissues through this pathway. Functional loss of two isoforms (CK1-α/ε) has been shown to activate the carcinogenic pathway which involves the stabilization of of cytoplasmic β-catenin. Development of anticancer therapeutics is very laborious task and depends upon the structural and conformational details of the target. This study focuses on, how the structural dynamics and conformational changes of two CK1 isoforms are synchronized in carcinogenic pathway. The conformational dynamics in kinases is the responsible for their action as has been supported by the molecular docking experiments.