We report on the preparation of cobalt-substituted nickel–zinc (Ni–Zn) ferrite aluminate nanoparticles (Ni0·3Zn0.7−xCoxFeAlO4) with x = 0.0–0.5 using sol–gel chemical synthesis method. The ...combination of metal ions forms the structure of a spinel cubic lattice for which the lattice parameter decreases and the crystallite size increases with increasing Co2+ substitution. We have determined the cation distribution of the ferrite aluminate with the help of X-ray diffraction analysis. Analysis of Fourier-transform infrared spectra demonstrates the formation of the spinel cubic structure. The nanocrystalline nature of the product with 28−34 nm sizes is determined from the transmission scanning-electron-microscope images. The saturation magnetization of the ferrite aluminates increases with increasing Co2+ ion substitution. The magnetocrystalline anisotropy also increases with increasing Co2+ substitution, influencing the coercivity of the ferrite aluminates. Analysis shows that the frequency-dependent complex permeability of the ferrite aluminates is controlled by domain-wall motion at lower frequencies and by spin rotations at higher frequencies.
The phase transition of bismuth-substituted nickel ferrite, synthesized by using a simple sol-gel autocombustion method, from cubic to perovskite is confirmed from the X-ray diffraction spectrums. ...The changes in isomer shift, hyperfine field and cation distribution are obtained from the Mossbauer spectroscopy analysis. The cation distribution demonstrates Ni2+ cations occupy tetrahedral sites, while Fe3+ and Bi3+ occupy both tetrahedral as well as octahedral sites. For higher concentrations of bismuth, saturation magnetization is increased whereas, coercivity is decreased which is related to phase change. The variations of dielectric constant, tangent loss and conductivity (ac) with frequency (10 Hz-5 MHz) have been explored with Bi3+-doping i.e. ‘x’. According to Maxwell-Wagener model, there is an involvement of electron hopping kinetics as both dielectric constant and tangent loss are decreased with increasing frequency. Increase of conductivity with frequency (measured at room temperature, 27 °C) is attributed to increase of number of carriers and mobility.
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•Due to phase change, for higher concentrations of bismuth, saturation magnetization is increased whereas, coercivity is decreased.•The cation distribution demonstrates Ni2+ cations occupy tetrahedral sites, while Fe3+ and Bi3+ occupy both tetrahedral as well as octahedral sites.•Dielectric constant, tangent loss and conductivity with frequency measurements confirm involvement of electron hopping kinetics.•Increase of number of carriers and mobility are evidenced.
Abstract
Cobalt substituted zinc ferrite aluminate series with compositional formula Zn
1‐
x
Co
x
FeAlO
4
(
x
= 0.0, 0.2, 0.4, and 0.6) is prepared by chemical sol–gel synthesis. The prepared ...samples are characterized by X‐ray diffraction (XRD), transmission electron microscope (TEM) technique. A cubic spinel phase is revealed by XRD analysis and confirmed from selected area electron diffraction (SAED) pattern. The true values of lattice constant are obtained from Nelson–Riley extrapolation plot, and lattice strain values are obtained with the help of Williamson‐Hall equation. The TEM image confirms average crystallite size of 31 nm. The dielectric study discloses the decrease of dielectric constant and loss tangent with the increasing frequency of applied field.
Plant saponins are widely distributed amongst plants and have a wide range of biological properties. Icosahydropicenic acid (IHPA), a new pentacyclic triterpenoid saponin was first time isolated from ...the roots of Clerodendrum Serratum (L) Moon (Verbenaceae). IHPA, at the dose of 100mg/kg, showed significant protection of mast cell degraualtion (59.62%) as compared to standard sodium cromoglycate (64.48%). The compound also revealed significant inhibitory activity on histamineinduced goat tracheal chain preparation. The study provides scientific basis for its clinical use in the treatment of asthma.
Drug degradation may change the pharmacological action and results in altered therapeutic and toxicological profile of drug. Identification of degradation product is good opportunity in the drug ...discovery, as non-toxic impurities can be considered for the new pharmacological potentials. Additionally, development of computer based in-silico model and methods further assist in prediction of pharmacokinetic, dynamic as well as biological activities which make drug discovery process more unfailing. In present work, Febuxotat (FEB) was subjected to forced degradation experiments and the formed degradation products were separated and resolved using optimized HPLC method. Further the study was extended to enrich its alkali degradation product and was ascertained using
1
H NMR spectroscopy and mass spectrometry. The ADME/Toxicological properties of alkali degradation product were determined by using Admet SAR 2.0. The method was validated as per ICH guidelines Q2 (R1). In forced degradation experiments, substantial degradation of FEB was observed under acid, alkali, wet heat, dry heat and oxidative conditions, however, FEB was found stable to photolytic conditions. The drug and its formed degradation products separated and resolved from each other on Waters SunFire C8 (250 × 4.6 mm, 5 µm) column using blend of methanol: 20 mM potassium phosphate buffer (pH 3.0) (80: 20 % v/v). From the
1
H NMR spectroscopy and mass spectrometry the enriched alkali degradation product was confirmed as 2-3-carboxy-4-(2-methylpropoxy) phenyl-4-methyl-1,3-thiazole-5-carboxylic acid (diacid FEB). Febuxostat and diacid Febuxostat was found non-toxic for carcinogenicity (binary), eye corrosion, eye irritation and Ames mutagenesis during ADME/Tox studies. However, both were found hepatotoxic. A simple, accurate, precise, and robust stability indicating HPLC method was developed and validated for the estimation of FEB in bulk and tablet dosage form. Based on ADME/Tox both were found to hepatotoxic. Henceforth, based on our evidences, one should use FEB with precaution in patient suffering from liver disease.
RECON UWB ANTENNA FOR COGNITIVE RADIO Niture, Deeplaxmi Vithalrao; Jadhav, Santosh S.; Mahajan, Shrinivas P.
Progress in electromagnetics research C Pier C,
2017, Volume:
79
Journal Article
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