Search

The oxide glass system of the composition (10 – x)SrO–xFe2O3–90V2O5, (x = 0, 2, 4, 6 and 8 mol %) were prepared by a standard melt quenching technique. The amorphous nature of the prepared glass was confirmed using X-ray diffraction technique. The infrared spectra of these glasses were recorded over a continuous spectral range (850–1500 cm–1). The density of prepared sample was obtained by the Archimedes principle. The physical parameters of the glasses were also determined with respect to the composition. Density increases from 3.10 to 3.20 g/cm3, whereas the molar volume decreases with the increase in Fe2O3 concentration. In order to study optical properties, absorption spectra were measured at room temperature. Indirect optical energy band gap, optical dielectric constant, refractive index were calculated from optical energy band gap. The refractive index decreases gradually with the increase in Fe2O3 content due to increase of bridging oxygen’s. For temperatures from 300 to 500 K, the dc conductivity increased with the increasing Fe2O3 content. The dielectric properties like dielectric constant, dielectric loss factor and dielectric loss tangent investigated at the room temperature in the frequency range of 10 kHz to 1 MHz decreases with frequency. The dielectric behavior shows strong frequency as well as composition dependence.

The present work deals with the synthesis and characterizations of magnesium-substituted cobalt ferrite (Co 1−x Mg x Fe 2 O 4; x = 0.00, 0.25, 0.50, 0.75, 1.00) nanoparticles by sol-gel auto combustion method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques were used for the characterization of the prepared samples. The magnetic properties were studied through pulse field hysteresis loop technique at room temperature. The XRD patterns of all the samples show the reflection which belongs to the cubic spinel structure. The XRD analysis confirmed the single-phase formation of spinel structure for the present ferrite system. Various structural parameters such as tetrahedral ionic radius (r A), the octahedral ionic radius (r B), theoretical lattice constant (a th), hopping length (L A and L B), tetrahedral bond length (d AL), octahedral bond length (d BL), tetra edge (d AE) and octa edge (d BE) were calculated from the XRD data. The variation of these structural parameters in magnesium composition has been studied. The M-H curves recorded at room temperature exhibit a typical hysteresis loop indicating that the sample exhibits a magnetic nature, which decreases with an increase in Mg content x. The large coercivity (H c) values indicate a nanocrystalline nature of the present samples. The coercivity, saturation magnetization, remanence magnetization, and magneton number decreases with an increase in Mg content x.

The purpose of the present study was to determine whether adrenal androgen suppression with dexamethasone (DEX) during ovulation induction improves the outcome of in-vitro fertilization (IVF) cycles. A total of 25 patients with serum dehydroepiandrosterone sulphate (DHEAS) concentrations2.5 micrograms/ml were randomized to receive either 0.5 mg DEX daily or placebo during ovulation induction with leuprolide acetate down-regulation plus human menopausal gonadotrophins (HMG). Nine patients undergoing a subsequent IVF cycle were crossed over to the other treatment group. Ovarian responsiveness and IVF outcome variables analysed included number of follicles12 mm in diameter, serum oestradiol concentrations on the day of human chorionic gonadotrophin (HCG) administration, number of ampoules of HMG administered, number of oocytes retrieved, percentage of oocytes fertilized, number of embryos transferred, implantation rate and numbers of clinical pregnancies and live birth pregnancies. The 31 randomized IVF cycles revealed a trend towards a higher implantation rate for the placebo-treated group compared to the DEX-treated group (24 versus 10%; P = 0.07). The remainder of the IVF cycle variables revealed no statistically significant differences. In conclusion, the suppression of adrenal androgens with DEX in women with DHEAS concentrations2.5 micrograms/ml appears to have no beneficial effects on ovarian responsiveness or clinical or live birth pregnancy rates.