Magdi Mohamed Mashly

MFe2O4 (M = Mn2+, Ni2+, Co2+ and Cu2+) ferrite powders were prepared by flash auto-combustion reaction. The structural identification of the samples was carried out using X-ray diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction (SAED) and IR spectra. The study established the formation of sub-nanosized particles especially for MFe2O4 (M = Ni, Co and Cu) ferrites. MFe2O4/PEG (polyethylene glycol) composites were prepared by cold uniaxial pressing. The magnetic properties were studied by carrying out the hysteresis of MFe2O4 and PEG/MFe2O4 composite at room temperature. The data showed that MnFe2O4 has the highest saturation magnetization while CoFe2O4 has the largest coercive field due to the high anisotropy of Co2+ ions. The ac electrical conductivity as well as the dielectric constant ε′ and loss tangent tan δ were measured at different frequencies at room temperature. The highest conductivity is achieved for PEG/Ni Fe2O4 and the lowest value of tan δ is obtained for PEG/MnFe2O4 amongst all PEG/MFe2O4 nanocomposites. © 2010 Elsevier B.V. All rights reserved.

MFe2O4 (M = Mn2+, Ni2+, Co2+ and Cu2+) ferrite powders were prepared by flash auto-combustion reaction. The structural identification of the samples was carried out using X-ray diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction (SAED) and IR spectra. The study established the formation of sub-nanosized particles especially for MFe2O4 (M = Ni, Co and Cu) ferrites. MFe2O4/PEG (polyethylene glycol) composites were prepared by cold uniaxial pressing. The magnetic properties were studied by carrying out the hysteresis of MFe2O4 and PEG/MFe2O4 composite at room temperature. The data showed that MnFe2O4 has the highest saturation magnetization while CoFe2O4 has the largest coercive field due to the high anisotropy of Co2+ ions. The ac electrical conductivity as well as the dielectric constant ε′ and loss tangent tan δ were measured at different frequencies at room temperature. The highest conductivity is achieved for PEG/Ni Fe2O4 and the lowest value of tan δ is obtained for PEG/MnFe2O4 amongst all PEG/MFe2O4 nanocomposites. © 2010 Elsevier B.V. All rights reserved.

MFe2O4 (M = Mn2+, Ni2+, Co2+ and Cu2+) ferrite powders were prepared by flash auto-combustion reaction. The structural identification of the samples was carried out using X-ray diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction (SAED) and IR spectra. The study established the formation of sub-nanosized particles especially for MFe2O4 (M = Ni, Co and Cu) ferrites. MFe2O4/PEG (polyethylene glycol) composites were prepared by cold uniaxial pressing. The magnetic properties were studied by carrying out the hysteresis of MFe2O4 and PEG/MFe2O4 composite at room temperature. The data showed that MnFe2O4 has the highest saturation magnetization while CoFe2O4 has the largest coercive field due to the high anisotropy of Co2+ ions. The ac electrical conductivity as well as the dielectric constant ε′ and loss tangent tan δ were measured at different frequencies at room temperature. The highest conductivity is achieved for PEG/Ni Fe2O4 and the lowest value of tan δ is obtained for PEG/MnFe2O4 amongst all PEG/MFe2O4 nanocomposites. © 2010 Elsevier B.V. All rights reserved.

\{MFe2O4\} (M = Mn2+, Ni2+, Co2+ and Cu2+) ferrite powders were prepared by flash auto-combustion reaction. The structural identification of the samples was carried out using X-ray diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction (SAED) and İR\} spectra. The study established the formation of sub-nanosized particles especially for \{MFe2O4\} (M = Ni, Co and Cu) ferrites. MFe2O4/PEG (polyethylene glycol) composites were prepared by cold uniaxial pressing. The magnetic properties were studied by carrying out the hysteresis of \{MFe2O4\} and PEG/MFe2O4 composite at room temperature. The data showed that MnFe2O4 has the highest saturation magnetization while CoFe2O4 has the largest coercive field due to the high anisotropy of Co2+ ions. The ac electrical conductivity as well as the dielectric constant ɛ′ and loss tangent tan δ were measured at different frequencies at room temperature. The highest conductivity is achieved for PEG/Ni Fe2O4 and the lowest value of tan δ is obtained for PEG/MnFe2O4 amongst all PEG/MFe2O4 nanocomposites.

The structure of some even-even superheavy nuclei with the proton number Z = 98-120 is studied using a semi-microscopic but not self-consistent model. The macroscopic energy part is obtained from the Skyrme nucleon-nucleon interaction in the semi-classical extended Thomas-Fermi approach. A simple but accurate method is derived for calculating the direct part of the Coulomb energy. The microscopic shell plus pairing energy corrections are calculated from the traditional Strutinsky method. Within this semi-microscopic approach, the total energy curves with the quadrupole deformation of the studied superheavy nuclei were calculated. The same approach features the well known 208Pb or 238U nuclei. For each nucleus the model predictions for the binding energy, the deformation parameters, the half-density radii and comparison with other theoretical models are made. The calculated binding energies are in good agreement with the available experimental data. © 2010 Pleiades Publishing, Ltd.

The structure of some even-even superheavy nuclei with the proton number Z = 98-120 is studied using a semi-microscopic but not self-consistent model. The macroscopic energy part is obtained from the Skyrme nucleon-nucleon interaction in the semi-classical extended Thomas-Fermi approach. A simple but accurate method is derived for calculating the direct part of the Coulomb energy. The microscopic shell plus pairing energy corrections are calculated from the traditional Strutinsky method. Within this semi-microscopic approach, the total energy curves with the quadrupole deformation of the studied superheavy nuclei were calculated. The same approach features the well known 208Pb or 238U nuclei. For each nucleus the model predictions for the binding energy, the deformation parameters, the half-density radii and comparison with other theoretical models are made. The calculated binding energies are in good agreement with the available experimental data. © 2010 Pleiades Publishing, Ltd.

The aim of this work was to study the effect on body composition, serum metabolic parameters and ovarian status of early weaning at 25 Days post-partum (dpp) as a strategy to decrease energy deficit of primiparous lactating rabbit does prior to insemination at 32 dpp following an extensive rhythm. A total of 34 primiparous lactating rabbit does were used and distributed in three groups: 10 lactating does euthanized at 25 dpp (group L25), 13 does weaned at 25 dpp and euthanized at 32 dpp (group NL32), and 11 non weaned lactating does euthanized at 32 dpp (group L32). No significant differences were observed in live body weight, ovary weight, serum NEFA and total protein concentration among groups. Although NL32 does had a low feed intake (122+/-23.5g/Day; P<0.001), their estimated lipids (16.9+/-1.09%, P<0.008), protein (19.7+/-0.07%, P<0.0001), and energy (1147+/-42.7MJ/kg, P<0.006) body contents were higher and their serum glucose concentrations (158+/-24.5mg/dl, P<0.04) were lower compared to L25 does (11.9+/-1.3%, 18.5+/-0.08%, 942+/-51.3MJ/kg and 212+/-27.9mg/dl) and L32 does (13.4+/-1.03%, 18.5+/-0.1%, 993+/-40.4MJ/kg and 259+/-29.5mg/dl), respectively. In the ovarian surface of L25 does a lower number of follicles > or =1mm was observed compared to NL32 and L32 groups (12.7+/-1.5 vs. 18.0+/-1.45 and 17.6 +/-1.67; P<0.05). Follicular population in the histological ovarian sections and immunolocalization of prolactin receptor were similar between groups. In group L25, both nuclear maturation of oocytes in terms of Metaphase II rate (67.0 vs. 79.7 and 78.3%; P<0.05) and cytoplasmic maturation measured by percentage of cortical granules (CG) totally or partially migrated in oocytes were significantly lower than in groups NL32 and L32 (16.0 vs. 38.3 and 60.0%; P<0.05). Consequently, a higher rate of oocytes with non-migrated CGs was found in group L25 than in groups NL32 and L32 (76.0 vs. 46.8 and 33.3%; P<0.05). In conclusion, even though early weaning at 25 dpp seemed to improve body energy stores of primiparous does, this fact was not well reflected on the ovarian status at 32 dpp, which was similar regardless of weaning time and it could be performed later.