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      • KCI등재

        Characterization of alanyl aminopeptidase from insecticide resistant and susceptible strains of Musca domestica L.

        Sohail AHMED1,Waqas WAKIL,David MANTLE,Richard M. WILKINS,권용정 한국곤충학회 2008 Entomological Research Vol.38 No.3

        To investigate the high activity of intracellular proteases in insecticide resistant strains of Musca domestica L., purification by anion-exchange chromatography and gel filtration of one of the enzymes, alanyl aminopeptidase (Ala AP), in three strains of Musca domestica was carried out. The fractions collected by gel filtration of soluble homogenates of the three strains (571ab, 17bb and Cooper) showed a single peak of Ala AP activity. Partially purified Ala AP of the three strains showed high activity at pH 7.5. The presence or absence of Ca2+ in the assay medium did not produce any difference in activity of Ala AP in the 571ab and Cooper strains, but there was a significant difference in the 17bb strain. The activity of Ala AP in all three strains was essentially unaltered in the presence of inhibitors of serine (PMSF), cysteine (E-64) proteases and carboxypeptidases (pepstatin). Ala AP hydrolyzed alanine amino methylcoumarin (Ala-AMC) maximally, followed by phenyl alanine amino methylcoumarin (Phe-AMC), leucyl amino methylcoumarin (Leu-AMC) and ornithine amino methylcoumarin (Orn-AMC). Ala AP from the three strains showed differential activity towards various substrates. The comparison of alanyl aminopeptidase’'s activity from different sources is discussed.

      • KCI등재후보

        A modified trans-anconeus approach to facilitate fixation of a posterior radial head fracture: a cadaveric feasibility study

        Ahmed Mohamed Desouky(Ahmed Mohamed Desouky ),Ahmed Naeem Atiyya(Ahmed Naeem Atiyya ),Mohamed Elbishbishi(Mohamed Elbishbishi ),Marwa Mohamed El Sawy(Marwa Mohamed El Sawy ) 대한해부학회 2023 Anatomy & Cell Biology Vol.56 No.1

        Fixation of radial head fracture with minimally invasive posterior approach remains a significant challenge. The aim of this study was to determine the feasibility of trans-anconeus posterior elbow approach and to observe lateral ulnar collateral ligament (LUCL) in extended elbows. This cadaveric study was performed in twenty upper limbs of fresh fixed adult male cadavers. An oblique incision was made in the middle segment of anconeus until the lateral ligament complex and the joint capsule had been revealed. A deep dissection was explored to observe the anatomical relationship of the LUCL to the anconeus. Measurements of the LUCL were recorded while the elbow was fully extended. The mean distance between the edge of the radial head and the proximal insertion of the LUCL was 13.3 mm (11.5–16.2 mm); the mean distance between the edge of the radial head and the distal insertion of the LUCL was 20.9 mm (19.2–23.4 mm); the distance between the edge of the radial head and the distal edge of the annular ligament was 11.2 mm (8.22–11.7 mm). By estimate correlation of the previous measurements, the direct and accessible way to expose the posterolateral articular capsule of the elbow joint was through a window in medial 2/3 of the middle segment of anconeus muscle. These trans-anconeus approach is useful. It provides good visualization, facilitates applying the implants, and lessens the risk of radial nerve injury. Awareness of the anatomy is mandatory to avoid injury of LUCL.

      • Poster Session : PS 0590 ; Critical Care Medicine ; Early CT Scan to Detect Anastomotic Leak: Is It Worth It?

        ( Ahmed Ahmed ),( Ayan Banerjea ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

        Background: Early diagnosis of anastomotic leakage after colorectal surgery and adequate treatment is crucial to reduce both morbidity and mortality. Computed tomography(CT) scanning is the diagnostic investigation of preference, but its role is questionable in the early postoperative days. The accuracy of CT scanning in the early postoperative period within the fi rst few days after surgery may even be lower when compared to a CT scan more than a week after surgery. Methods: 185 patients underwent 1 or more bowel anastomosis during the period of 6 months. A prospective data sheet was updated regularly with post op morbidity and mortality. The type of anastomosis, timing of postoperative CT scan, diagnosis of leakage and accuracy of the CT scan in detecting it were all recorded. Results: 54 patients (29%) had CT scans post operatively, of whom 48 happened during the same admission with a mean time of 5±3 days postoperatively.A total of 9 patients had their fi rst CT scan onday 3 or earlier postoperatively with one leak detected on that. The mean time for diagnosing a leak was 14±8 days. Conclusions: Timely and correct diagnosis and treatment of anastomotic leakage after bowel surgery remains to be a major challenge.Clinical decision remains of utmost importance in the individual patient and should therefore not depend on one specifi c clinical or additional diagnostic factor.

      • Static bending response of axially randomly oriented functionally graded carbon nanotubes reinforced composite nanobeams

        Ahmed Amine Daikh,Ahmed Drai,Mohamed Ouejdi Belarbi,Mohammed Sid Ahmed Houari,Benoumer Aour,Mohamed A. Eltaher,Norhan A. Mohamed Techno-Press 2024 Advances in nano research Vol.16 No.3

        In this work, an analytical model employing a new higher-order shear deformation beam theory is utilized to investigate the bending behavior of axially randomly oriented functionally graded carbon nanotubes reinforced composite nanobeams. A modified continuum nonlocal strain gradient theory is employed to incorporate both microstructural effects and geometric nano-scale length scales. The extended rule of mixture, along with molecular dynamics simulations, is used to assess the equivalent mechanical properties of functionally graded carbon nanotubes reinforced composite (FG-CNTRC) beams. Carbon nanotube reinforcements are randomly distributed axially along the length of the beam. The equilibrium equations, accompanied by nonclassical boundary conditions, are formulated, and Navier's procedure is used to solve the resulting differential equation, yielding the response of the nanobeam under various mechanical loadings, including uniform, linear, and sinusoidal loads. Numerical analysis is conducted to examine the influence of inhomogeneity parameters, geometric parameters, types of loading, as well as nonlocal and length scale parameters on the deflections and stresses of axially functionally graded carbon nanotubes reinforced composite (AFG CNTRC) nanobeams. The results indicate that, in contrast to the nonlocal parameter, the beam stiffness is increased by both the CNTs volume fraction and the length-scale parameter. The presented model is applicable for designing and analyzing microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS) constructed from carbon nanotubes reinforced composite nanobeams.

      • KCI등재

        Fundamental Output Voltage Enhancement of Half-Bridge Voltage Source Inverter with Low DC-link Capacitance

        Ahmed Elserougi,Ahmed Massoud,Shehab Ahmed 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

        Conventionally, in order to reduce the ac components of the dc-link capacitors of the two-level Half-Bridge Voltage Source Inverter (HB-VSI), high dc-link capacitances are required. This necessitates the employment of short-lifetime and bulky electrolytic capacitors. In this paper, an analysis for the performance of low dc-link capacitances-based HB-VSI is presented to elucidate its ability to generate an enhanced fundamental output voltage magnitude without increasing the voltage rating of the involved switches. This feature is constrained by the load displacement factor. The introduced enhancement is due to the ac components of the capacitors’ voltages. The presented approach can be employed for multi-phase systems through using multi single-phase HB-VSI(s). Mathematical analysis of the proposed approach is presented in this paper. To ensure a successful operation of the proposed approach, a closed loop current controller is examined. An expression for the critical dc-link capacitance, which is the lowest dc-link capacitance that can be employed for unipolar capacitors’ voltages, is derived. Finally, simulation and experimental results are presented to validate the proposed claims.

      • KCI등재

        On Separation Axioms in Fuzzifying Bitopological Spaces

        Ahmed Abd El-Monsef Allam,Ahmed Mohammed Zahran,Ahmed Khalf Mousa,Hana Mohsen Binshahnah 한국지능시스템학회 2020 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.20 No.1

        In present paper, we introduce and study the concepts of T₀<SUP>(i;j)</SUP>-, T₁<SUP>(i;j)</SUP> -, T₂<SUP>(i;j)</SUP>(pairwise Hausdorff)-, TR<SUP>(i;j)</SUP> (pairwise regularity)-, TN<SUP>(i;j)</SUP> (pairwise normality)-, R₀<SUP>(i;j)</SUP>-, R₁<SUP>(i;j)</SUP>-, T₃<SUP>(i;j)</SUP> - and T₄<SUP>(i;j)</SUP> - separation axioms in fuzzifying bitopological spaces and study some relations between them. Also we investigate the image of these kinds of fuzzifying bitopological spaces under some types of fuzzy mappings.

      • KCI등재

        Control of Open-Loop PWM Delta-Connected Motor-Drive Systems under One Phase Failure Condition

        Ahmed Sayed-Ahmed,Nabeel A. O. Demerdash 전력전자학회 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.6

        A new fault-tolerant control topology for open-loop motor-drive systems with Delta-connected stator windings is introduced in this paper. This new control topology enables the operation of a three-phase induction machine as a two-phase machine fed by a three-phase inverter upon a failure in one of the motor phases. This topology utilizes the “open-Delta” configuration to independently control the current in each of the two remaining healthy phases. This new control technique leads to the alleviation of any torque pulsations resulting from the consequences of the asymmetrical conditions associated with this class of faults.

      • KCI등재

        A Buck-Boost Converter-Based Bipolar Pulse Generator

        Ahmed A. Elserougi,Ahmed M. Massoud,Shehab Ahmed 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.6

        This paper presents a buck-boost converter-based bipolar pulse generator, which is able to generate bipolar exponential pulses across a resistive load. The concept of the proposed approach depends on operating the involved buck-boost converters in discontinuous current conduction mode with high-voltage gain and enhanced efficiency. A full design of the pulse generator and its passive components is presented to ensure generating the pulses with the desired specifications (rise time, pulse width, and pulse magnitude) for a given load resistance and input dc voltage. In case of moderate pulsed output voltages (i.e. few of kV), one module of the presented bipolar generator can be employed. While in case of high-voltage pulsed output, multi-module version can be employed, where each module is fed from an isolated dc source and their outputs are connected in series. Simulation models for the proposed approach are built to elucidate their performance in case of one-module as well as multi-module based generator. Finally, a scaled-down prototype for one-module of buck-boost converter-based bipolar pulse generator is implemented to validate the proposed concept.

      • KCI등재

        Review : Nanoparticles as Alternative Pesticides: Concept, Manufacturing and Activities

        ( Ahmed I S Ahmed ),( Youn Su Lee ) 한국균학회 2015 韓國菌學會誌 Vol.43 No.4

        Nanotechnology, which has become an important area of science, has caused an enormous developmental revolution in many fields. In the last two decades researchers have focused on overcoming the obstacles encountered during the preparation of nanoparticles. This article highlights the nanotechnology, along with a brief description of the manufacturing, concepts and activities of nanoparticles as alternative pesticides against plant pathogens, some methods for evaluation of nanoparticles against phytopathogens in vitro and in vivo, and explains the importance of some common nanoparticle types used in agricultural applications and plant pathology.

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