Phytochemical composition, protective and therapeutic effect on gastric ulcer and a-amylase inhibitory activity of Achillea biebersteinii Afan.

Howaida I. Abd-Alla,Nagwa M. M. Shalaby,Manal A. Hamed,Nagy Saba El-Rigal,Samira N. Al-Ghamdi,Jalloul Bouajila 대한약학회 2016 Archives of Pharmacal Research Vol.39 No.1

Three sesquiterpene lactones [two germacranolides (micranthin and sintenin) and one guaianolide (4b,10adihydroxy- 5b,7b,8bH-guaia-1,11(13)dien-12,8a-olide)] and four derivatives of 3-methoxy flavones (santin, quercetagetin- 3,6,30-trimethyl ether, quercetagetin-3,6-dimethyl ether, and 5,7 dihydroxy 3,30,40-trimethoxy flavone) were isolated from the ethyl acetate extract (EAE) of the aerial parts of Achillea biebersteinii Afan. (Asteraceae). Evaluation of protective and therapeutic effects of EAE against ethanol-induced gastric ulcer in rats was carried. Antiulcer activity evaluation was done through measuring ulcer indices, stomach acidity, gastric volume and lesion counts. Oxidative stress markers; malondialdehyde, glutathione and superoxide dismutase were also estimated. The work was extended to determine the histopathological assessment of the stomach. Gastric ulcer exhibited a significant elevation of the ulcer index and oxidative stress markers. The extract attenuated these increments and recorded protective and therapeutic effects against gastric ulcer. Hyperglycaemia increases the mucosal susceptibility to ulcerogenic stimuli and predisposes gastric ulceration. In vitro a-amylase inhibitory assay was applied to evaluate the post prandial antihyperglycaemia activity. The result showing that the EAE has the ability to reduce starch-induced postprandial glycaemic excursions by virtue of potent intestinal a-amylase inhibitory activity. These findings demonstrated the remarkable potential of A. biebersteinii as valuable source of antiulcer agent with post prandial hyperglycaemia lowering effect.

Comparative analysis on darcy-forchheimer flow of 3-D MHD hybrid nanofluid (MoS₂-Fe₃O₄/H₂O) incorporating melting heat and mass transfer over a rotating disk with dufour and soret effects

A.M. Abd-Alla,Esraa N. Thabet,S.M.M.El-Kabeir,H. A. Hosham,Shimaa E. Waheed Techno-Press 2024 Advances in nano research Vol.16 No.4

There are several novel uses for dispersing many nanoparticles into a conventional fluid, including dynamic sealing, damping, heat dissipation, microfluidics, and more. Therefore, melting heat and mass transfer characteristics of a 3-D MHD Hybrid Nanofluid flow over a rotating disc with presenting dufour and soret effects are assessed numerically in this study. In this instance, we investigated both ferric sulfate and molybdenum disulfide as nanoparticles suspended within base fluid water. The governing partial differential equations are transformed into linked higher-order non-linear ordinary differential equations by the local similarity transformation. The collection of these deduced equations is then resolved using a Chebyshev spectral collocation-based algorithm built into the Mathematica software. To demonstrate how different instances of hybrid/ nanofluid are impacted by changes in temperature, velocity, and the distribution of nanoparticle concentration, examples of graphical and numerical data are given. For many values of the material parameters, the computational findings are shown. Simulations conducted for different physical parameters in the model show that adding hybrid nanoparticle to the fluid mixture increases heat transfer in comparison to simple nanofluids. It has been identified that hybrid nanoparticles, as opposed to single-type nanoparticles, need to be taken into consideration to create an effective thermal system. Furthermore, porosity lowers the velocities of simple and hybrid nanofluids in both cases. Additionally, results show that the drag force from skin friction causes the nanoparticle fluid to travel more slowly than the hybrid nanoparticle fluid. The findings also demonstrate that suction factors like magnetic and porosity parameters, as well as nanoparticles, raise the skin friction coefficient. Furthermore, It indicates that the outcomes from different flow scenarios correlate and are in strong agreement with the findings from the published literature. Bar chart depictions are altered by changes in flow rates. Moreover, the results confirm doctors' views to prescribe hybrid nanoparticle and particle nanoparticle contents for achalasia patients and also those who suffer from esophageal stricture and tumors. The results of this study can also be applied to the energy generated by the melting disc surface, which has a variety of industrial uses. These include, but are not limited to, the preparation of semiconductor materials, the solidification of magma, the melting of permafrost, and the refreezing of frozen land.

Thermal stresses in an infinite circular cylinder

A. M. Abd-Alla,G. A.Yahya,A. M. Farhan 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.6

In the present paper, the problem of dynamic thermal stresses in an infinite elastic cylinder of radius a, with its axis along the z-axis,subject to certain boundary conditions, is studied. This type of situation can arise due to melting at constant rate of an insulating material at zero temperature deposited on the positive half of the infinite cylinder. A solution and numerical results are obtained for the stress components, displacement components, and temperature. Numerical results are given and illustrated graphically for each case considered.

Long wavelength peristaltic flow in a tubes with an endoscope subjected to magnetic field

Abd-Alla, A.M.,Abo-Dahab, S.M.,El-Semiry, R.D. 한국유변학회 2013 Korea-Australia rheology journal Vol.25 No.2

In this paper, this study examines problem of peristaltic flow in a tubes with an endoscope subjected to magnetic field. Effect of an endoscope and magnetic field on the peristaltic flow of a Jeffrey fluid through the cylindrical cavity between concentric tubes has been investigated. The analytical expressions for the pressure gradient, velocity, pressure rise, friction force on the inner and outer tubes and shear stress are obtained in the physical domain. Effect of the non-dimensional wave amplitude, the magnetic field, the ratio of relaxation to retardation time, the radius ratio and the non-dimensional volume flow are analyzed theoretically and computed numerically. Comparison were made with the results obtained in the presence and absence of magnetic field and an endoscope. The results indicate that the effect of the non-dimensional wave amplitude, magnetic field, ratio of relaxation to retardation time, radius ratio and non-dimensional volume flow on peristaltic flow are very pronounced.

Rotational effect on Rayleigh, Love and Stoneley waves in fibre-reinforced anisotropic general viscoelastic media of higher and fraction orders with voids

A. M. Abd-Alla,Aftab Khan,S. M. Abo-Dahab 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

In this paper, we investigated the propagation of surface waves in a rotating fibre-reinforced viscoelastic anisotropic media of a higherorder and fraction orders of nth order including time rate of strain with voids. The general surface wave speed is derived to study theeffect of rotation and voids on surface waves. Particular cases for Stoneley, Love and Rayleigh waves are also discussed. The resultsobtained in this investigation are more general in the sense that some earlier published results are obtained from our result as special cases. In order zero our results are well agreeing with classical results. Also by neglecting the reinforced elastic parameters and voids the resultsreduce to well known isotropic medium. Comparison was made with the results obtained in the presence and absence of rotation andparameters for fibre-reinforced of the material medium. It is observed that Love wave remains unaffected with respect to rotation andvoids. It is also observed that, surface waves cannot propagate in a fast rotating medium. Numerical results are given and illustratedgraphically.

Long wavelength peristaltic flow in a tubes with an endoscope subjected to magnetic field

A. M. Abd-Alla,S. M. Abo-Dahab,R.D. El-Semiry 한국유변학회 2013 Korea-Australia rheology journal Vol.25 No.2

In this paper, this study examines problem of peristaltic flow in a tubes with an endoscope subjected to magnetic field. Effect of an endoscope and magnetic field on the peristaltic flow of a Jeffrey fluid through the cylindrical cavity between concentric tubes has been investigated. The analytical expressions for the pressure gradient, velocity, pressure rise, friction force on the inner and outer tubes and shear stress are obtained in the physical domain. Effect of the non-dimensional wave amplitude, the magnetic field, the ratio of relaxation to retardation time, the radius ratio and the non-dimensional volume flow are analyzed theoretically and computed numerically. Comparison were made with the results obtained in the presence and absence of magnetic field and an endoscope. The results indicate that the effect of the non-dimensional wave amplitude, magnetic field, ratio of relaxation to retardation time, radius ratio and non-dimensional volume flow on peristaltic flow are very pronounced.

Oscillation and nonoscillation of nonlinear second order difference equations}

M. M. A. EL-Sheikh,M. H. Abd Alla,E. M. EL-Maghrabi 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.21 No.1-2

Rotational effect on thermoelastic Stoneley, Love and Rayleigh waves in fibre-reinforced anisotropic general viscoelastic media of higher order

A.M. Abd-Alla,S.M. Abo-Dahab,Aftab Khan 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.61 No.2

In this paper, we investigated the propagation of thermoelastic surface waves in fibre-reinforced anisotropic general viscoelastic media of higher order of nth order including time rate of strain under the influence of rotation. The general surface wave speed is derived to study the effectsof rotation andthermal onsurface waves. Particular cases for Stoneley, Love and Rayleighwaves are discussed.The results obtained in this investigation are more general in the sense that some earlier published results are obtained from our result as special cases. Our results for viscoelastic of order zero are well agreed to fibre-reinforced materials. Comparison was made with the results obtained in the presence and absence of rotation and parameters for fibre-reinforced of the material medium. It is also observed that, surface waves cannot propagate in a fast rotating medium.Numerical results for particular materials are given and illustrated graphically. The results indicate that the effect of rotation on fibre-reinforced anisotropic general viscoelastic media are very pronounced.

Propagation of Rayleigh waves in a rotating orthotropic materialelastic half-space under initial stress and gravity

A. M. Abd-Alla,S. M. Abo-Dahab,T. A. Al-Thamali 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.9

This paper aims to investigate the influence of rotation, initial stress and gravity field on the propagation of Rayleigh waves in a homogeneous orthotropic elastic medium. The government equations and Lame's potentials are used to obtain the frequency equation which determines the velocity of Rayleigh waves, including rotation, initial stress and gravity field, in a homogeneous, orthotropic elastic medium has been investigated. The numerical results analyzing the frequency equation are discussed and presented graphically. It is important to note that the Rayleigh wave velocity in an orthotropic elastic medium increases a considerable amount in comparison to the Rayleigh wave velocity in an isotropic material. The results indicate that the effects of rotation, initial stress and gravity field on Rayleigh wave velocity are very pronounced.

Analytical solution of wave propagation in a non-homogeneous orthotropic rotating elastic media

A. M. Abd-Alla,S. R. Mahmoud 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.3

In this paper, the natural frequencies of the radial vibrations of a hollow cylinder and hollow sphere with different boundary conditions under influences of rotation and non-homogeneity have been studied. The radial vibrations of orthotropic material as affected by the angular velocity are investigated on the basis of the linear theory of elasticity. The of elastodynamic equations have been solved in analytical form. Numerical results are given and illustrated graphically for each case. Comparisons are made with previous results which given in the absence of rotation and non-homogeneity. The results indicate that the effect of rotation and non-homogeneity is very pronounced.