El-Remaily M.A.E.A.A.A.,Sohag University
Tetrahedron | Year: 2014
Magnetic Fe3O4 nanoparticles as a heterogeneous catalyst, were found to be efficient for the synthesis of a series of pyranopyrazoles by a four component reaction of a mixture of hydrazine hydrate, ethyl acetoacetate, aldehydes/ketones and malononitrile in water at room temperature. The products were attributed to the nanosize of about 16 nm in which the catalyst could act as a nanoreactor. The present protocol offers the advantages of clean reaction, short reaction time, high yield, easy purification and economic availability of the catalyst. © 2014 Elsevier Ltd. All rights reserved.
Ahmed S.A.,Sohag University
Solid State Communications | Year: 2010
We report here observation of ferromagnetism in pure and Mn doped SnO 2 powder with different Mn contents. Magnetic measurements revealed that all samples exhibit room temperature ferromagnetism (RTFM), which is identified as an intrinsic characteristic. The RTFM has been observed in the pure SnO2 powder, which is believed to be defect induced, with a saturation magnetization of ∼0.017 emug. The RTFM was enhanced considerably in the Mn doped samples and the magnetic properties strongly depend on doping content. A sample with 1% of Mn is ferromagnetic at room temperature with a saturation magnetization of ∼0.98 emug, a remanent magnetization of ∼27%, and a coercivity of ∼270 Oe. The average magnetic moment per Mn atom decreases with increasing Mn content. Our results reveal that the large RTFM observed in Mn doped SnO2 powder originates from a combination effect of oxygen vacancies and transition metal doping. © 2010 Elsevier Ltd. All rights reserved.
Noaman H.H.,Sohag University
Annals of Plastic Surgery | Year: 2013
Sixteen patients (11 men and 5 women), who formed the basis of the study, underwent surgery in the Hand and Reconstruction Microsurgical Unit, Orthopedic Department, Sohag Faculty of Medicine, from January 2001 to January 2009.The right side was involved in 7 cases and the left side in 9 cases. Average age was 35.2 years. The causes of bone defects were infected nonunion of both bone forearms in 5 cases, infected nonunion of the middle part of radius in 4 cases, posttraumatic bone loss of distal radius in 4 cases, and tumor of shaft humerus in 3 cases (aneurysmal bone cyst in 1 and osteosarcoma in 2 patients).The principle of treatment was debridement and excision of either infected unhealthy bone or tumor tissues with wide safety margin.The average bone defect was 8 cm (range, 6-14 cm). The defect was bridged by osteoseptocutaneous vascularized fibular bone graft. The donor bone was the right fibula in 7 cases and the left fibula in 10 cases. Two grafts were used in 1 patient because of soft tissue injuries, which included the peroneal vessels during osteotomy. The vascularized fibula was fixed by small dynamic compression plate. The operative time ranged between 7 and 11 hours. Blood transfusion was indicated in all the cases and its average transfusion was 1000 mL. The average follow-up was 84 months. Bone union was ultimately obtained in 15 patients except 1 who had failure of the graft. Arthrodesis of the distal ulna with the wrist joint was done during the follow-up. Arthrodesis of the wrist joint was also performed for 1 patient who had loss of carpal bones, distal radius, and wrist and finger extensors. The average time for union was 3.5 months. The hand function was normal in all cases. Stress fracture and fibular donor-site morbidity did not occur in this series. Neither shoulders nor elbows were affected postoperatively. There was no recurrence for either infection or tumor. © 2013 Lippincott Williams & Wilkins.
Mahmoud E.E.,Sohag University
Nonlinear Dynamics | Year: 2010
Our main objective in this work is to investigate complete synchronization (CS) of n-dimensional chaotic complex systems with uncertain parameters. An adaptive control scheme is designed to study the synchronization of chaotic attractors of these systems. We applied this scheme, as an example, to study complete synchronization of chaotic attractors of two identical complex Lorenz systems. The adaptive control functions and the parameters estimation laws are calculated analytically based on the complex Lyapunov function. We show that the error dynamical systems are globally stable. Numerical simulations are computed to check the analytical expressions of adaptive controllers. © 2010 Springer Science+Business Media B.V.
Mahmoud E.E.,Sohag University
Mathematical and Computer Modelling | Year: 2012
The aim of this paper is to introduce a new hyperchaotic complex Lorenz system. This hyperchaotic complex system is constructed by adding a linear controller to the second equation of the chaotic complex Lorenz system. The new system is a 7-dimensional continuous real autonomous hyperchaotic system. This system has hyperchaotic attractors and quasi-periodic solutions with three zero Lyapunov exponents, while the chaotic attractors exist for all the parameters values of this system with two zero Lyapunov exponents. The fractional Lyapunov dimension of the hyperchaotic attractors of this system is calculated. Bifurcation diagrams are used to demonstrate chaotic and hyperchaotic behaviors of new system. The active control method based on Lyapunov stability analysis is used to study synchronization of this system. Numerical simulations are implemented to verify the results of these investigations. © 2011 Elsevier Ltd.