Synthesis and Characterization of Zinc and Vanadium Co-Substituted CoFe2O4 Nanoparticles Synthesized by Using the Sol-Gel Auto-Combustion Method.

In recent years, cobalt ferrite has attracted considerable attention due to its unique physical properties. The present study aimed to produce cobalt ferrite magnetic nanoparticles doped with zinc and vanadium using the sol-gel auto-combustion method. For this purpose, Co1-xZnxFe2-yVyO4 (where x = 0.0, 0.1, 0.2, 0.5 and y = 0.00, 0.05, 0.15, 0.25) precursors were calcined at 800 °C for 3 h. The prepared samples were characterized with the X-ray diffraction (XRD) method in combination with Rietveld structure refinement, field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometery (VSM). The XRD patterns confirmed the formation of crystalline spinel structure for all samples. However, the diffraction peaks of hematite and iron vanadium oxide phases were observed in the patterns of some doped samples. The average crystallite size for all the synthesized samples was found to be in the range of ~45-24 nm, implying that it decreased by simultaneously doping cobalt ferrite with Zn and V. The FT-IR spectrum confirmed the formation of the spinal structure of ferrite through the observed vibrational bands assigned to the tetrahedral (υ2) and octahedral (υ1) interstitial complexes in the spinel structure. The FE-SEM images showed that morphology, average grain size, and agglomeration of the synthesized powders were affected by doping, which was due to the interactions of the magnetic surface of nanoparticles. The VSM curves demonstrated that saturation magnetization and coercivity values changed in the range of 30-83 emu/g and from 27-913 Oe, respectively. These changes occurred due to the alteration in cation distribution in the spinel structure. This can be attributed to the change in superexchange interactions between magnetic ions by co-substitution of Zn and V ions in Cobalt ferrite and the changes in magnetocrystalline anisotropy.

Isokinetic Analysis of Fe41Co7Cr15Mo14Y2C15B6 Bulk Metallic Glass: Effect of Minor Copper Addition.

In the present study, (Fe41Co7Cr15Mo14Y2C15B6)100-xCux (x = 0, 0.25 and 0.5 at.%) amorphous alloys were prepared by copper-mold casting. To clarify the effect of the minor addition of copper on the mechanism of nucleation and growth during the crystallization process, an isokinetic analysis was performed. The activation energies (E) of the various crystallization stages were calculated by using theoretical models including Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO), Augis-Bennett and Gao-Wang methods. In addition, Augis-Bennett, Gao-Wang and Matusita methods were used to investigate the nucleation and growth mechanisms and to determine other kinetic parameters including Avrami exponent (n), the rate constant (Kp) and dimensionality of growth (m). The obtained results revealed that the activation energy-as well as thermal stability-was changed with minor addition of copper. In addition, the obtained Avrami exponent values were confirmed by Johnson-Mehl-Avrami-Kolmogorov (JMAK) method. The research findings demonstrated that the value of Avrami exponent is changed with minor addition of copper, so that the Avrami exponents of all crystallization stages, except the second peak for copper-free amorphous alloy, were equal to integer values ranging from two to four, indicating that the growth mechanisms were controlled by interface. Moreover, the kinetic parameters of n and b for all peaks were increased by an increase in crystallization temperature, which can be attributed to the increase in the nucleation rate.

Function of vitrified mouse ovaries tissue under static magnetic field after autotransplantation.

This study was designed to investigate the effects of applying 1 mT static magnetic field (SMF) during the vitrification process, on the viability of ovarian follicles after vitrification-warming and autotransplantation. The study was conducted in two phases. In the first phase, ovaries of female NMRI mice (6 to 8 weeks old) were randomly divided into three groups: 1- Freshly isolated ovaries fixed in Bouin solution (control group), 2- Ovaries vitrified-warmed without exposure to magnetic field (V1 group) and 3- Ovaries exposed to magnetic field during equilibration step of the vitrification process (V2 group). In the second phase, the vitrified (V1 and V2 groups) and fresh ovarian tissues were autografted into the back muscles of the mice from which the ovaries were extracted. In both phases, morphological aspects and molecular characteristics of active-apoptotic caspase-3 antibody were evaluated. Results indicated the lower percentages of morphologically intact primordial, primary and antral follicles in the V1 group (67.6, 49.5 and 17.6%, respectively) than those of control (97.3, 85.4 and 42.1%, respectively) and V2 (94.1, 78.8 and 40.9%, respectively) groups. In addition, the mean percentages of morphologically intact follicles in the V1 group were statistically lower than those in other groups, after transplantation. The rate of apoptosis in preantral follicles of the V1 group was significantly higher than that in the other groups. It was concluded that exposure of mice ovaries to SMF during vitrification resulted in greater resistance to injuries.

Comparison of Allotransplantation of Fresh and Vitrified Mouse Ovaries to The Testicular Tissue under Influence of The Static Magnetic Field.

OBJECTIVES: The aim of this study was to investigate the effects of static magnetic field (SMF) during transplantation of the ovarian tissue into the testis. MATERIALS AND METHODS: In this experimental study, ovaries of 6- to 8-week-old female Naval Medical Research Institute (NMRI) mice were randomly divided into four groups: i. Fresh ovaries were immediately transplanted into the testicular tissue (FOT group), ii. Fresh ovaries were exposed to the SMF for 10 minutes and then transplanted into the testicular tissue (FOT+ group), iii. Vitrified-warmed ovaries were transplanted into the testicular tissue (VOT group), and iv. Vitrified-warmed ovaries were transplanted into the testicular tissue and the transplantation site was then exposed to the SMF for 10 minutes (VOT+ group). RESULTS: The lowest percentages of morphologically dead primordial follicles and the highest percentages of morphologically intact primordial follicles were seen in the FOT+ group (4.11% ± 2.88 and 41.26% ± 0.54, respectively). Although the lowest significant percentage of maturation, embryonic development and fertility was observed in the VOT group as compared to the other groups, the difference in the fertility rate was not significant between the VOT and VOT+ groups. Estrogen and progesterone concentrations were significantly higher in the FOT+ group than those of the control mice. CONCLUSIONS: It is concluded that, exposure of the vitrified-warmed ovaries to SMF retains the structure of the graft similar to that of fresh ovaries.

Polymorphism of Myostatin Gene in Intron 1 and 2 and Exon 3, and Their Associations with Yearling Weight, Using PCR-RFLP and PCR-SSCP Techniques in Zel Sheep.

The aim of present study was to investigate myostatin gene polymorphism and its association with yearling weight records in Zel sheep using PCR-RFLP and PCR-SSCP methods. Blood samples were collected from 200 Zel sheep, randomly, and DNA was extracted using modified salting out method. Polymerase chain reaction was carried out to amplify 337, 222, and 311 bp fragments, respectively, comprising a part of exon 3, intron 1, and intron 2 of myostatin gene. In addition, exon 3 was digested by HaeIII enzyme under RFLP method, and introns 1 and 2 were studied using SSCP. Under RFLP method, all samples showed mm genotype. Under SSCP method, intron 1 was also monomorph but intron 2 was polymorph (AA, AB, and BB). The allelic frequencies for A and B were 75.5 and 24.5%, respectively. This locus was not in Hardy-Weinberg equilibrium (P < 0.05), and there was no significant effect of myostatin gene on yearling weights.

Effect of Papaver rhoeas extract on in vitro maturation and developmental competence of immature mouse oocytes.

PURPOSE: This experiment examined the effect of Papaver rhoeas L. extract on in vitro maturation, in vitro fertilization (IVF) and subsequent developmental competence of mouse oocytes. MATERIALS AND METHODS: Cumulus oocyte complexes (COCs) at germinal vesicle stage were collected from female Naval Medical Research Institute (NMRI) mouse ovaries. The COCs were transferred to maturation medium supplemented with different concentrations of P. rhoeas extract. Two trials were carried out to examine the effect of low concentrations (0, 10, 15, 20, 25 µg/ml) and high concentrations (0, 50, 100, 200 µg/ml) of the extract. The maturation rate was recorded. After IVF, embryos were cultured and their developmental process was monitored for 96 h. RESULTS: Maturation rate and blastocyst formation improved by using low concentrations of the extract; however, no significant increase was observed when compared to the control group. In addition no significant differences were observed in the fertilization rates of oocytes treated with both low and high concentrations compared to the control group. However, among higher concentrations, 100 µg/ml, P. rhoeas extract significantly increased both the in vitro maturation rate and in vitro developmental (IVD) competence when compared to the control group (P < 0.05). CONCLUSIONS: It was concluded that natural extracts increase the IVD competence of oocytes. The improved effect on oocyte maturation was dependent on the addition of optimum concentrations of P. rhoeas extract to the maturation medium.