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Cu-doped CoFe2O4 spinel ferrites with composition CuxCo1-xFe2O4: x = 0.05, 0.1, 0.15, 0.2 have been synthesized by sol–gel self-combustion method. Cation distribution using XRD data by intensity ratio and Rietveld method revealed perfect inverse spinel structure, further confirmed with Vibration Sample Magnetometer (VSM) results explaining two sub-lattice collinear models. The room temperature VSM analysis reveals ferromagnetism in all compositions of the samples with a maximum saturation value of 73.587 emu/g at 1.5 T for the composition x = 0.15 and maximum coercivity 1754.67 G and squareness ratio 51% for the composition x = 0.2. The above result may be the highest value of coercivity and squareness ratio reported at room temperature for Cu- doped CoFe2O4 spinel ferrites. The electron density distribution using XRD data utilizing Maximum Entropy Method (MEM) visualizes the electronic structure. All compositions show strong tetrahedral A–O covalent bonding with Oxygen ions. Moderate covalent octahedral B–O ionic bonding for the compositions x = 0.05, 0.1 and 0.15 and ionic bonding for the composition x = 0.2 are observed. The composition Cu0.2Co0.8Fe2O4 with the maximum tetrahedral covalent and octahedral ionic bonding has the highest observed magnetic parameters. [ABSTRACT FROM AUTHOR]

Single-phase, nanocrystalline Zn2+ substituted cubic spinel CaFe2O4 with the composition ZnxCa1-x Fe2O4 (x = 0.0, 0.05, 0.1, 0.15) was prepared by solvothermal method. The magnetic properties of the prepared samples were analysed by vibration sample magnetometer (VSM), which reveals a switching from soft ferromagnetic behaviour to super-paramagnetic for an increase in Zn2+ doping concentration. The maximum coercivity of 405.54 G and squareness ratio of 35.8% is obtained for pure CaFe2O4, and the doping of nonmagnetic Zn2+ ions gradually loses the ferromagnetism. Neel's two sublattices' collinear model well explains the overall magnetic property. The surface morphology and elemental composition were analysed using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis. An optical bandgap analysis was carried out using UV–Visible spectroscopy, revealing a random variation of the optical energy gap with composition. X-ray peak analysis reveals the single-phase cubic spinel structure with Fd-3 m space group. The estimated crystallite sizes range from 22 to 39 nm, and lattice parameter varies in random fashion with the increase of Zn2+ doping concentration. Mixed cubic spinel structure is revealed from cation distribution analysis. Rietveld refinement technique is utilised for structural refinements. The maximum entropy method (MEM) is used for the experimental electron density analysis and hence bonding. The 3D, 2D and 1D MEM analyses reveal the weakest tetrahedral A–tetrahedral A bonding and the alteration in tetrahedral A–octahedral B and octahedral B–octahedral B bond strength with doping. Moderate A–O and B–O covalent bonding favours maximum saturation magnetism of 83.59 emu/g for the composition Zn0.05Ca0.95Fe2O4. [ABSTRACT FROM AUTHOR]

Cobalt and manganese-substituted zinc ferrite XZnFeO (X = Co, Mn) nanoparticles have been synthesized by co-precipitation method and characterized for structural, morphology, and magnetic properties by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). The Rietveld refinement method is employed to refine the XRD powder data, and the structural parameters are calculated from the refinement. Substitution of cobalt and manganese causes the lattice parameter to decrease. Particle size, measured from XRD, lies in the nanometer regime. A low saturation magnetization value is obtained in both samples, and the presence of non-collinear spin arrangement is found at octahedral sites. The maximum entropy method (MEM) is employed to study the strength of the bond between the atoms at tetrahedral and octahedral sites in the unit cell of ferrites. Optical band gap energy of the samples is determined by using UV-VIS techniques. [ABSTRACT FROM AUTHOR]

The dielectric properties such as dielectric constant both real and imaginary part, dielectric loss factor, and AC resistivity have been studied in this work on mechanically alloyed Ni0.5Zn0.5Fe2O4 nano ferrite particles sintered from 700 to 1200 °C as a function of frequency in the range of 0.1 Hz to 15 MHz. The dielectric constant (ε′) decreases with increase in sintering temperature and the decrease is explained with proper mechanism. The samples sintered at 900 and 1200 °C show slightly high ε′ value compared to their predecessor. The AC resistivity at room temperature is found to be of the order of 109 Ω-cm. [ABSTRACT FROM AUTHOR]

In this article, numerical values of the bond strength between tetrahedral-tetrahedral, octahedral-octahedral, and tetrahedral-octahedral site interactions in ferrites are evaluated by using maximum entropy method (MEM) and compared with that of existing theoretical predictions for the NiZnFe O nanoferrite particles prepared by mechanical alloying via high-energy ball milling and sintered at different temperatures from 1100 to 1400 C. Interestingly, octahedral-octahedral site interactions are found to have the weakest interaction in all the samples. The structural parameters of the prepared sample have been studied by employing the Rietveld refinement method, using JANA 2006 software. The magnetic properties and the optical band gap energy of the samples are determined using vibrating sample magnetometer and UV-VIS technique respectively. [ABSTRACT FROM AUTHOR]

Our aim was to investigate whether human insulin (HI) or insulin glargine treatment could promote the proliferation of thyroid cells and determine the association between type 2 diabetes and thyroid disease. Rats were treated with different doses of HI and insulin glargine. Plasma glucose and the phosphorylation levels of the insulin receptor (IR), insulin-like growth factor 1 receptor (IGF-1R), protein kinase B (Akt), and extracellular signal-regulated kinase 1/2 (ERK1/2) were measured. A total of 105 rats were randomly assigned to three groups as follows: control group, HI group, and glargine group. Both drugs promoted the phosphorylation of IR, Akt, and ERK1/2 in a dose-dependent manner (p < 0.05), and the effect of glargine persisted for longer period. Treatment with ultra-therapeutic doses of HI or glargine (p < 0.05) increased the expression of Ki-67 in thyroid cells. The results demonstrated that therapeutic doses of glargine have a longer-lasting hypoglycemic control than HI. Based on the results, HI or glargine did not stimulate thyroid cell proliferation at therapeutic doses, but high doses did.