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Arish, Egypt

Abou-El-Naga I.F.,Alexandria University | Radwan E.H.,Damnhour University
Revista de Biologia Tropical | Year: 2012

In Egypt, Biomphalaria alexandrina is the intermediate host for Schistosoma mansoni. The fates of Schistosoma miracidia in the snails varies between different species of Biomphalaria. The internal defense system is one of the factors that influence the susceptibility pattern of the snails. The interaction between Biomphalaria snails and S. mansoni needs to be identified for each species, and even between the members of the same species with different degrees of susceptibility. In the present study, the first generation of susceptible and resistant parents of B. alexandrina was examined histologically at the 30th day post exposure. The study includes the characterization of the immune response, as expressed by tissue reactions, of susceptible and resistant B. alexandrina snails against S. mansoni. It was also designed to determine the impact of the resistance increase in parent snails, on the mechanisms of interaction of their offspring against infection. The results showed that the infection rate of the offspring from the susceptible parents was 92%. No susceptible offspring was produced from the resistant parents. When the parents were of equal number of susceptible and resistant snails, they gave an offspring with an infection rate of 20%. Susceptible snails that had susceptible parents showed a higher degree of susceptibility than those that had both susceptible and resistant parents. A common feature of the resistant snails was the absence of any viable parasites. The tissue reactions of the resistant snails having only resistant parents occurred at the site of miracidial penetration. In resistant snails for which susceptible ones were included in their parents, the reactions occurred in the deep tissues. These results characterized the immune response of B. alexandrina snails against Schistosoma infection which was found to occur by two different mechanisms. One type of defense occurs in highly resistant snails, and employs direct miracidial destruction soon after parasite penetration. The other type occurs in less resistant snails where a delayed resistance development occurs after the dissemination of the sporocysts in the snail tissues. It seems that B. alexandrina snails respond more or less similar to B. glabrata. The results also proved that the immune response of the internal defense system increased with increasing the number of the inherited resistant genes. Source

Aly A.A.,Damnhour University | Selim M.M.,Damietta University
European Physical Journal Plus | Year: 2015

The f(T) modified gravity model is considered in the framework of fractal space-time. Assuming only the time has a fractal profile while the other spatial coordinates have their normal geometrical descriptions, the Hubble parameter, H, the dark energy density, (Formula presented.) , the deceleration parameter, q, the pressure P, and state finder parameters r and s are reconstructed for our model. It is interesting to mention here that all the results are consistent with the recent present observations. © 2015, Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg. Source

Aly A.A.,Damnhour University | Fekry M.,King Saud University | Mansour H.,Cairo University
International Journal of Modern Physics D | Year: 2015

Within the framework of Chern-Simons (CS) modified gravity, we studied dark energy models. The new agegraphic dark energy (NADE) model, entropy-corrected new agegraphic dark energy (ECNADE) model and NADE model with generalized uncertainty principle (GUP) are investigated. For these models, we studied the evolution of scale factor a, Hubble parameter H and deceleration parameter q. On meantime, we studied the state finder parameters s and r. These models show some similar behavior with modified Chaplygin gas model in some regions, while in other regions some similarity with phantom and quintessence dark energy is noticed. © 2015 World Scientific Publishing Company. Source

Pasqua A.,University of Trieste | Aly A.A.,Damnhour University
European Physical Journal Plus | Year: 2014

This paper reports a study on the cosmological application of interacting Ricci Dark Energy (RDE) density in the scalar Gauss-Bonnet framework. The interacting holographic RDE model has been employed to obtain the equation of state (EoS) in a spatially flat universe. The main results of this paper are that the reconstructed potential of scalar Gauss-Bonnet gravity for the interacting RDE model decays with the evolution of the universe. However, it is an increasing function of the scalar field (Formula presented.) . Both the strong and weak energy conditions are violated. A phantom-like behavior of the EoS parameter has been obtained. The effective EoS parameter (Formula presented.) stays below -1 but tends to -1 with the evolution of the universe. However, it cannot cross the phantom boundary. Finally, the interacting RDE model in Gauss-Bonnet gravity gives accelerated expansion of the universe. © 2014, Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg. Source

Mona M.H.,Tanta University | Elkhodary G.M.,Damnhour University | Khalil A.M.,Zagazig University
Life Science Journal | Year: 2011

The effect of varying algal cell concentration, food items and temperature on the filtration and ingestion rates of the eyed larva of Crassostrea gigas were investigated under laboratory condition. The filtration and ingestion rates were measured according to the indirect method in which the flow of water into the passage cavity is inferred from the rate of removal of suspended particles. Cultures of the unicellular alga Isochrysis galbana and Pavlovia lutheri were used in the test solutions. Three different concentrations of the two algal species (100,50 and 25 cells/μl) and three temperature degrees (25 °c, 20 °c and 13 °c) were used to study the effect of these factors at different time intervals from starting the experiments (1, 6 and 12 days) on the filtration and ingestion rates of the eyed-larvae. The filtration and ingestion rates of the larvae of C.gigas that recorded by using I. galbana were large than that of P. lutheri. These results might depend on the size of the filtered particles. Moreover, the larvae of C. gigas regulate filtration rates according to the particle concentration in the surrounding medium, filtration was more actively in lower concentrations (25 × 106 L-1I. galbana) than at the higher ones (100 × 106 L-1I galbana). The mean value of filtration and ingestion rates of C.gigas were significantly increased by the increase in temperature degree and 25°c were considerable the perfect temperature to achieve high values of both filtration and ingestion rates if it is compared by 20 °c and 13 °c. These results help to explain the feeding behavior of C.gigas. Source

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