Magnetic,Mössbauer and optical spectroscopic properties of the AFe3O(PO4)3 (A = Ca,Sr, Pb) series of powder compounds

AFe₃O(PO₄)₃ (A = Ca, Sr and Pb) powder compounds were studied by means of X-ray diffraction (XRD), electron-probe microanalysis (EPMA) coupled with wavelength dispersion spectroscopy (WDS), Raman and diffuse reflectance spectroscopies, specific heat and magnetic properties measurements. Magnetization, magnetic susceptibility and specific heat measurements carried out on AFe₃O(PO₄)₃ (A = Sr, Ca and Pb) powders firmly establish a series of three ferromagnetic (FM)-like second order phase transitions spanned over the 32–8 K temperature range. Room temperature Mössbauer spectroscopy and associated DFT calculations confirm the existence of three crystallographically non equivalent Fe³⁺ sites in the three compounds. Mössbauer spectra recorded as a function of temperature in the PbFe₃O(PO₄)₃ compound also establishes the occurrence of two purely magnetic and reversible phase transitions at 32 and 10 K. Diffuse reflectance measurements reveal two broad absorption bands at 1047 and 837 nm, in both PbFe₃O(PO₄)₃ and SrFe₃O(PO₄)₃ powders, with peak cross sections ∼10⁻²⁰ cm² typical of spin-forbidden and forced electric dipole intraconfigurational transitions.     

Two-Dimensional Layered Metallic VSe2/SWCNTs/rGO Based Ternary Hybrid Materials for High Performance Energy Storage Applications

In this work, the ternary hybrid structure VSe₂/SWCNTs/rGO is reported for supercapacitor applications. The ternary composite exhibits a high specific capacitance of 450 F g⁻¹ in a symmetric cell configuration, with maximum energy density of 131.4 Wh kg⁻¹ and power density of 27.49 kW kg⁻¹. The ternary hybrid also shows a cyclic stability of 91 % after 5000 cycles. Extensive density functional theory (DFT) simulations on the structure as well as on the electronic properties of the binary hybrid structure VSe₂/SWCNTs and the ternary hybrid structure VSe₂/SWCNTs/rGO have been carried out. Due to a synergic effect, there are enhanced density of states near the Fermi level and higher quantum capacitance for the hybrid ternary structure compared to VSe₂/SWCNTs, leading to higher energy and power density for VSe₂/SWCNTs/rGO, supporting our experimental observation. Computed diffusion energy barrier of electrolyte ions (K⁺) predicts that ions move faster in the ternary structure, providing higher charge storage performance.     

Zn and Zr co-doped M-type strontium hexaferrite: Synthesis,characterization and hyperthermia application

In the present study, hard ferromagnetic (M-type strontium hexaferrite) SrFe₁₂O₁₉ was co-doped by Zn and Zr for magnetic hyperthermia applications. As a result of the high concentration of single domain SrFe₁₂O₁₉ nanoparticles (suspended in the ferrofluid), they found a large hydrodynamic diameter, which caused a long-time Brownian relaxation under the AC magnetic field. On the other hand, increasing the Zn-Zr content (low concentration of SrFe₁₂O₁₉) led to a drop in anisotropy, which coincided with a short-time N´eel relaxation. All of the substituted samples with a multi-disperse state in ferrofluid exhibited an almost equal amount of the N´eel and Brownian effects. Consequently, the magnetic saturation (M_s) was considered as the dominant factor in the specific absorption rate (SAR) of the substituted samples. Transformation to the mono-disperse state was followed by the decrease of the Brownian relaxation time and hence the increase of the SAR. The interesting point in mono-disperse state was the heat generation of pure SrFe₁₂O₁₉ under the AC magnetic field as a result of the decrement of the Brownian relaxation time.     

Impedance Response of a Thin Film on an Electrode: Deciphering the Influence of the Double Layer Capacitance

The different contributions of the interfacial capacitance are identified in the case of passive materials or thin protective coatings deposited on the electrode surface. The method is based on a graphical analysis of the EIS results to determine both the passive-film capacitance in the high-frequency domain and the double-layer capacitance in the low-frequency domain. The proposed analysis is shown to be independent of the physicochemical origins of the frequency dispersion of the interfacial capacitances which results, from an analysis point of view of the experimental results, in the use of a constant-phase element However, for a correct evaluation of the thin-film properties such as its thickness, the high-frequency data must be corrected for the double-layer contribution. In particular, it is shown that if the double-layer capacitance gives a frequency-dispersed response, it is necessary to correct the high-frequency part for the double-layer constant-phase elements. This is first demonstrated on synthetic data and then used for the determination of the thickness of thin oxide film formed on Al in neutral pH solution.     

Where the rubber meets the hand: Unlocking the sensing potential of dielectric elastomers

Practice makes perfect to some extent. Research has shown that musicians who practice the piano for long periods of time can suffer a range of hand problems from loss of control to diminished speed. Now imagine a rubber keyboard that is springy, soft, and elastic. This is the new type of input device that dielectric elastomers (DE) can create. However their usage in large sensing systems is limited by a scalability challenge. Each DE sensor is married to a pair of connection cables and electronics, adding to the complexity of the background overheads. A new efficient multi‐frequency method is presented that is capable of detecting internal pressure changes from a difference in the DE's capacitance without the need for any additional wires or connections. This effectively segments the DE into smaller sections, achieving information from a single sensor equivalent to multiple sensors. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 465–472     

PPy modified titanium foam electrode with high performance for supercapacitor

Pyrrole was polymerized on the surface of titanium foam using FeCl₃ as oxidant and the as-synthesized product could be directly used as electrode for supercapacitor. The globular polypyrrole (PPy) particles were firmly loaded on the substrate with high density. The morphology study of PPy film is observed in SEM images, the XRD, FTIR and UV–vis spectra reveal the structure and crystalline of PPy nanoparticles. The electrochemical properties of PPy modified electrode are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and cycle life techniques. The electrochemical measurements showed such a PPy–Ti electrode had a wide working potential window, a high specific capacitance of 855 F g⁻¹ and excellent cycle stability at a discharge current density of 1 A g⁻¹.     

Mutation scanning analysis of genetic variation within and among Echinococcus species: Implications and future prospects

Adult tapeworms of the genus Echinococcus (family Taeniidae) occur in the small intestines of carnivorous definitive hosts and are transmitted to particular intermediate mammalian hosts, in which they develop as fluid‐filled larvae (cysts) in internal organs (usually lung and liver), causing the disease echinococcosis. Echinococcus species are of major medical importance and also cause losses to the meat and livestock industries, mainly due to the condemnation of infected offal. Decisions regarding the treatment and control of echinococcosis rely on the accurate identification of species and population variants (strains). Conventional, phenetic methods for specific identification have some significant limitations. Despite advances in the development of molecular tools, there has been limited application of mutation scanning methods to species of Echinococcus. Here, we briefly review key genetic markers used for the identification of Echinococcus species and techniques for the analysis of genetic variation within and among populations, and the diagnosis of echinococcosis. We also discuss the benefits of utilizing mutation scanning approaches to elucidate the population genetics and epidemiology of Echinococcus species. These benefits are likely to become more evident following the complete characterization of the genomes of E. granulosus and E. multilocularis.     

Neuroprotective glucosides of magnolol and honokiol from microbial-specific glycosylation

Thirteen new glucosides (1–13) of magnolol and honokiol were obtained from specific O-glycosylation by two filamentous fungi, Cunninghamella echinulata AS 3.3400 and Rhizopus japonicus ZW-4. The glucosides' structures were determined on the basis of extensive spectroscopic (HRESIMS, 1D and 2D NMR, and CD) analyses and a chemical method. C. echinulata appeared to transfer a glucosyl moiety to 2-OH of magnolol and honokiol, whereas R. japonicus preferred to regio-specifically transfer a glucosyl moiety to 4′-OH when honokiol was as the substrate. In addition, hydroxylation by C. echinulata and specific 6″-O-acylation of the introduced glucosyl moiety by R. japonicus were observed as minor reactions. Bioassay results indicated that glucosides 1–12 together with magnolol and honokiol at 10 μM attenuated the glutamate-induced toxicity in SK-N-SH cells to levels comparable to the results for MK-801, a positive control. However, the water-solubility of major glucosylated products (1, 8, and 11) increased greatly.     

GPCR A2A AR腺苷受体蛋白的激动剂结合及其诱导的蛋白活性开关构象变化

运用分子动力学模拟,研究了腺苷酸（激动剂）与A2AAR腺苷受体蛋白的相互作用和配体结合诱导的蛋白动力学变化．识别了与腺苷酸结合力强于0．5kcal／mol的关键基团：A63^2．61,I66^2．64,V84^3.32,L85^3.33,T88^3.36,F168^5.29,M177^5.38,L249^6.51,H250^6.52和N253^6.55,观察到腺苷酸没有与L167^5.28相互作用,这一结果支持了L167^5.28是抑制剂特异性结合位点,不与激动剂结合．未结合配体（激动剂或抑制剂）的单体A2AAR和腺苷酸结合后的A2AAR在构象上有三个不同功能性开关．腺苷酸结合可以诱导A2AAR腺苷受体蛋白的构象调整,使得三个功能性开关器件的构象与单体A2AAR不同．