Increasing Antimicrobial Resistance Monitored in Surveillance Analysis of Blood Stream Infections in Febrile Neutropenic Pediatric Oncology Patients

El-Mahallawy, Hadir A,Hassan, Safaa Shawky,El-Wakil, Mohamed,Moneer, Manar M,Shalaby, Lobna Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.14

Background: Continuous surveillance of pattern of blood stream infection is necessary in febrile neutropenia (FN)especially with the recent escalating trend in the management of pediatric cancer patients towards intensified regimens and with the increase in infections caused by resistant organisms limiting the choice of antibiotics. Aim: To monitor change in pattern of blood stream infections (BSI) in FN pediatric cancer patients. Materials and Methods: Surveillance of FN episodes with positive BSI was prospectively monitored and compared to a previous surveillance in the same pediatric oncology unit. Results: A total of 232 BSI positive episodes were documented in 192 patients during a 6 months period. The results of recent surveillance analysis showed an increase in intensified regimens of chemotherapy, antimicrobial resistance, fungal infections, and prolonged duration of episodes when compared to previous surveillance, with p value sof <0.001, 0.005, 0.021, and <0.001, respectively. There was an apparent decrease in the crude mortality but this was not statistically significant, to 6% in 2011 from 10 % in 2006. Conclusions: The pattern of BSI at our institution is still inclining towards gram positive organisms but is showing a shift towards more antibiotic resistance and fungal infections.

3D FEM simulations for the homogeneity of plastic deformation in Al–Cu alloys during ECAP

Mahallawy, Nahed El,Shehata, Farouk A.,Hameed, Mohamed Abd El,Aal, Mohamed Ibrahim Abd El,Kim, Hyoung Seop Elsevier 2010 Materials science & engineering. properties, micro Vol.527 No.6

<P><B>Abstract</B></P><P>Equal channel angular pressing (ECAP) is a material processing method that allows very high strains to be imposed, leading to extreme work hardening and microstructural refinement. To investigate the deformation homogeneity in the transverse direction, rigid-viscoplastic 3D finite element simulations were conducted for the different numbers of ECAP passes of Al with Cu contents 0–5%. The simulation results indicated that the material on the outer side of the die channel undergoes less deformation than that in the inner side due to the formation of a corner gap. It was also found that the homogeneity increased with increasing the number of ECAP passes and the copper content due to the decrease in the size of the corner gap. To verify the 3D finite element simulation results, the microhardness homogeneity across the transverse direction of the billet was measured. The same trend was observed: the homogeneity in hardness increased with increasing the number of ECAP passes and Cu contents from 0% to 5%. The homogeneity of deformation indicated by microhardness and by FEM results was higher for route A compared with route Bc and increases with the number of ECAP passes. The homogeneity in route A was higher than that in route Bc by 10% after 2 passes up to 8 passes.</P>

Wear properties of ECAP-processed ultrafine grained Al-Cu alloys

Abd El Aal, M.I.,El Mahallawy, N.,Shehata, F.A.,Abd El Hameed, M.,Yoon, E.Y.,Kim, H.S. Elsevier Sequoia 2010 Materials science & engineering. properties, micro Vol.527 No.16

The wear properties of equal channel angular pressing (ECAP) Al-2, 3 and 5%Cu alloys under dry sliding conditions using different sliding distances and loads were investigated by pin-on-disc dry sliding wear tests. The wear mass loss decreased remarkably as the number of ECAP passes and Cu content increased, being affected more by the sliding distance than by the applied load under the experimental conditions. The wear mechanism was observed to be adhesive and delamination initially, and an abrasive mechanism also appeared as the sliding distance increased. The analysis of the wear surface indicates a transfer of Fe from the rotating disc to the Al-Cu alloy pin with increases in the sliding distance, the applied load, the number of passes and the copper content.

Recessive Trait Crossover Genetic Algorithm Flight Control System Design

A. A. El-Mahallawy,A. A. Madkour,A. M. Yousef,H. A. Yousef,M. I. El-Singaby 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

The requirements, design and simulation of a flight control system for precision tracking task, called pitchrate control augmentation system, is considered. This control system is designed for the F-16 fighter aircraft model using the recessive trait crossover genetic algorithm. The behavior of this controller is compared with that of H￥- mixed sensitivity approach. The flight simulations reveal that the desired performance objectives are achieved and that the controller provides acceptable performance in spite of modeling errors and plant parameter variations.

Tensile Properties and Fracture Characteristics of ECAP-Processed Al and Al-Cu Alloys

Mohamed Ibrahim Abd El Aal,Nahed El Mahallawy,Farouk A. Shehata,Mohamed Abd El Hameed,윤은유,이정환,김형섭 대한금속·재료학회 2010 METALS AND MATERIALS International Vol.16 No.5

In the present paper, billets of pure Al, and cast-homogenized Al-2 wt.%, 3 wt.%, and 5 wt.% Cu alloys were successfully processed by equal channel angular pressing (ECAP) up to 10 passes without fracture at room temperature using a die with a channel angle of 110o. Giant strains imposed on workpieces lead to extreme dislocation densities, microstructural refinement, and finally ultrafine grained materials. Tensile tests were employed to examine the fracture modes and fracture surface morphologies of the ECAP-processed Al and Al-Cu alloy samples. In particular, the effects of the number of ECAP passes and the Cu content were investigated.

Characterization of swarf Al/ (Al2O3 /GNs) Ag composite fabricated using stir casting and rolling process

Hossam M. Yehia,Nasreen Abdelalim,I. El-Mahallawi,Tamer Abd-elmotaleb,W. Hoziefa 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

In this study, alumina and graphite in a 98 % to 2 % ratio were prepared by mechanical milling for 80 hrs, then surface coated with 2 %Ag. The motorcycle wheel aluminum swarf was melted at 800 °C then the new hybrid (Al 2 O 3 -GNs)Ag in proportions of 1, 2, and 3 wt% was added at 600 rpm for 10 min. The microstructure of the rolled samples showed a good distribution of the hybrid (Al 2 O 3 -GNs)Ag and good adhesion with the aluminum matrix. The hardness increased by adding alumina and the hybrid up to 3 %. The as-rolled 3 %(Al 2 O 3 -GNs)Ag samples gave the best mechanical properties (yield strength, tensile strength, and elongation) compared to the as-cast aluminum reinforced with alumina and hybrid. The corrosion rate was improved by reinforcing the aluminum with the hybrid (Al 2 O 3 -GNs)Ag. Due to reducing the particles size and increasing the surface area after the rolling process, a deterioration in the corrosion resistance was observed.

A molecular dynamics study of the effect of Coulomb Buckingham Potential on equilibrium structural properties of calcium titanate perovskite

Ibrahim Almishal Saeed Sameer,Hatem Tarek M.,El-Mahallawi Iman S. 한국물리학회 2022 Current Applied Physics Vol.40 No.-

The demand on new and highly efficient energy conversion systems and many other advanced applications have suggested perovskites to be important future candidate materials. Though a lot of work has been done to understand and model their structure and properties, further investigation is still needed. Consequently, the development and enhancement of computational methods including molecular dynamics and quantum chemical calculations is one of the main issues regarding the understanding and optimization of perovskites. In this work, Coulomb Buckingham interatomic potential function is investigated to analyze the structure of Calcium Titanate CaTiO3 through the application of Molecular Dynamics via LAMMPS open source code. The results are compared with the results of other potential functions representations, namely Vashishta-Rahman (VR) and Lennard-Jones (LJ) potentials. The understanding of the effect of potential representation on structural properties would lead to deduction of mechanical and thermal properties and to building a platform for adapting the different types of oxide perovskites, or even nonorganic halide perovskites, to enhance their technological aspects. The VR interaction potential was previously proven to be the most effective for describing the phase changes of perovskites and to match the experimental observations. It was also proven in previous studies that the radial distribution function (RDF) undergoes essential changes when replacing LJ with VR. According to the findings of this study, Buckingham potential is shown to produce much closer results to VR than LJ of the radial distribution function.

Structure and thermoelectric behavior of polyaniline-based/ CNT-composite

Abd-Elsalam Ayat,Badr Hussein O.,Abdel-Rehim Ahmed A.,El-Mahallawi Iman S. 한국물리학회 2022 Current Applied Physics Vol.36 No.-

Thermoelectric materials have the capability of harvesting and converting the heat wasted into useful electrical current. Polymer thermoelectric composites have recently received attention and experienced a rapid development because of their low density, versatility, ease of synthesis and processing and low thermal conductivity. Herein, we report on synthesis and characterization of pristine polyaniline and polyaniline/carbon nanotubes network nanocomposite. In the preparation, aniline was polymerized via a facile chemical oxidative polymerization process, in which 30 wt% multiwall carbon nanotubes were in situ incorporated. Both pristine polyaniline and its composite were examined by XRD. For their thermoelectric performance, Seebeck coefficient and electrical conductivity were characterized using a home-built setup operated by keithley Multimeter (Model:2000). The fabricated composite exhibited superior increase in Seebeck coefficient and power factor to reach 141 μV/K and 0.004 μW/mK2, respectively at 95 ◦C. The corresponding I–V curves were further measured. The current was found to increase substantially to reach 2.2 mA at 1 V; almost one order of magnitude higher when compared to that of the pristine polyaniline sample.