Mohammed El-Shahat

Ferrite samples having the general formula Ni1-xZn xLa0.05Fe1.95O4 were prepared using the standard ceramic method. The effect of sintering temperature, heating rate, and sintering time on the structural and the electrical properties was studied. The data show that electrical conductivity in σ as well as dielectric constant ε′ are highly dependent on both Zn content x and the sintering conditions. The data obtained show that 1250°C is a critical sintering temperature. At this sintering temperature the grain growth is increased as the formation of spinel structure reaches its maximum value, and the volume diffusion is predominant. The critical heating rate is 4°C/min where the full reaction and maximum densification occur simultaneously. The effect of sintering time was also studied at a constant heating rate of 4°C/min and sintering temperature of 1250°C. All the data obtained are nearly constant and begin to increase after 83 h. SEM and electrical properties confirmed the results obtained. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ferrite samples having the general formula Ni1-xZn xLa0.05Fe1.95O4 were prepared using the standard ceramic method. The effect of sintering temperature, heating rate, and sintering time on the structural and the electrical properties was studied. The data show that electrical conductivity in σ as well as dielectric constant ε′ are highly dependent on both Zn content x and the sintering conditions. The data obtained show that 1250°C is a critical sintering temperature. At this sintering temperature the grain growth is increased as the formation of spinel structure reaches its maximum value, and the volume diffusion is predominant. The critical heating rate is 4°C/min where the full reaction and maximum densification occur simultaneously. The effect of sintering time was also studied at a constant heating rate of 4°C/min and sintering temperature of 1250°C. All the data obtained are nearly constant and begin to increase after 83 h. SEM and electrical properties confirmed the results obtained. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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The effect of α-tocopherol, simvastatin and both on male fertility in hypercholesterolemic rats was studied. Induction of hypercholesterolemia was done by feeding rats on a diet containing 1% cholesterol for 30 days. Hypercholesterolemic rats were orally given α-tocopherol (3 mg kg−1 BW) or simvastatin (1 mg kg−1 BW) or both for 65 days. Fertility index, serum testosterone level, sex organs weight, semen analysis and histopathological examination of testes, seminal vesicles and prostate glands were the parameters used to evaluate the reproductive efficiency of rats. In hypercholesterolemic rats (control +ve), there was a marked decrease in fertility index, testicular weight, sperm cell count, and percentages of sperm motility and viability associated with a significant increase in sperm cell abnormalities. Oral administration of either α-tocopherol or simvastatin to hypercholesterolemic rats for 65 days significantly improved the fertility index, testicular weight and semen quality. Concomitant administration of α-tocopherol and simvastatin to hypercholesterolemic rats markedly increased fertility index and sperm motility and viability associated with a significant reduction of sperm cell abnormalities. Histopathological examination revealed that testes of hypercholesterolemic rats (control +ve) had degenerated, non-functioning and atrophied seminiferous tubules associated with arrest of spermatogenesis. Oral administration of α-tocopherol and simvastatin concomitantly to hypercholesterolemic rats resulted in active mature and full functioning seminiferous tubules. In conclusion, concomitant administration of α-tocopherol and simvastatin to hypercholesterolemic male rats improved their reproductive efficiency and produced additional protection against reduced fertility induced by hypercholesterolemia.

The effect of hexacontatetrapole deformation parameter on both the fusion cross-section and the barrier distribution have been studied for U238 + O16 nuclear pair using microscopically derived heavy ion (HI) potential. A method was described to extend the calculation of HI potential between two spherical nuclei using density dependent finite range NN forces to the spherical-deformed interacting pair. Density dependent and density independent effective NN forces were used in the generalized double folding model to derive the HI potential. We found that positive β6 has large effect on both the fusion cross-section and the barrier distribution in the presence of a small value of hexadecapole deformation parameter β4. In this case the fusion cross-section is less sensitive to the negative value of β6. In the presence of a large value of β4, negative and positive β6 values affect the fusion cross-section and have a small effect on the barrier distribution.