684 research outputs found

    Two-Port Versus Three-Port Laparoscopic Appendectomy In Children

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    Background/Purpose: Laparoscopic appendectomy is the routine technique for management of acute appendicitis in children in many centers. In this study, the classic three-port technique is compared to the two-port technique in the noncomplicated non-difficult acute appendicitis. Materials & Methods: This is a retrospective study of the cases of non-complicated acute appendicitis treated laparoscopically between June 2003 and June 2009. Cases treated by the two-and three -port techniques were compared regarding the operative duration, operative and postoperative complications and the length of hospital stay. Results: During the study period, 85 children (45 males and 40 females) had laparoscopic appendectomy for acute noncomplicated appendicitis; 48 children by the Three-port technique (group I) and 37 children by the Two-port technique (group II).The mean age was 9.7 years (range 4 – 13). The mean operative duration was 40 minutes (range 30-70) in group I and 25 minutes in group II (range 17-35). Operative bleeding occurred in 9 cases (19%) (group I) and 8 cases (22%) group II, operative rupture of the appendix in 1(2%) , Port site infection (redness or discharge) in 3 (6%) in group I and none in group II, Postoperative ileus ( > 48 hours) 3 (6%) in group I and 1(2.7%) in group II. The mean length of hospital stay was 2.3 days in group I and 2 days in group II. Three cases in group II were converted to total laparoscopic appendectomy because of residual long stump (conversion rate 8%). Conclusion: The Two-port laparoscopic appendectomy had less operative duration and length of hospital stay than the threeport technique in non-complicated non-difficult acute appendicitis in children. However, the operative and post operative complications were almost the same.Index Word: Laparoscopy, appendectomy

    A method to suppress dielectric breakdowns in liquid argon ionization detectors for cathode to ground distances of several millimeters

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    We present a method to reach electric field intensity as high as 400 kV/cm in liquid argon for cathode-ground distances of several millimeters. This can be achieved by suppressing field emission from the cathode, overcoming limitations that we reported earlier

    Utility of Certain Nucleophilic Aromatic Substitution Reactions for the Assay of Ethamsylate in its Dosage forms and in Presence of its Degradation Product

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    The study represents the first report on the development of spectrophotometric methods for determination of ethamsylate (EST) in the presence of hydroquinone as an impurity and/or acidic degradation product. The proposed methods are based on the reaction of EST through it,s secondary amino group either with 1,2-naphthoquinone-4-sulphonate sodium (NQS) at pH 10.7 or 2,4-dinitrofluorobenzene (DNFB) at pH 9.3 to form orange and yellow colored reaction products peaking at 478 and 387 nm for methods (I) and (II), respectively. The different experimental parameters affecting the development and stability of the reaction products in methods (I) and (II) were carefully studied and optimized. The absorbance-concentration plots were rectilinear over the concentration ranges of 2-30 and 2-14 µg mL−1 for methods (I) and (II), respectively. The lower detection limits were 0.13 and 0.19 µg mL−1 and the lower quantitation limits were 0.44 and 0.63 µg mL−1 for methods (I) and (II), respectively. Both methods were successfully applied to commercial ampoules and tablets

    SOME ASPECTS OF ENERGY SAVING OF BURDEN MATERIAL IN THE BLAST FURNACE

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    To determine the possibility of self-stabilization effect for burden surface texture and gas flow in operating blast furnace under the proper conditions was experimentally proved for the first time, as well as the reasons of the effect disruption

    Some properties of NaBaPO[4]:Eu luminophore surface

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    There is an increased interest to the compounds of the ABPO[4] type, activated by europium, where A and B are mono- and divalent cations, because of their luminescent properties. In this paper NaBaPO[4]:Eu{2+}phosphors with different europium content were synthesized by SHS method. It is shown that phosphor surface becomes less alkaline (pHiis changes in the interval 10,7-9,5) with an increase in the concentration of an introduced activator (5-12%). Two bands with maxima wavelength of approximately 425 and 490 nm are observed in the luminescent spectra (the positions of maxima differ somewhat in different spectra). The relationship between acid-base and luminescent properties of the investigated phosphor samples is traced

    An efficient chameleon swarm algorithm for economic load dispatch problem

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    Economic Load Dispatch (ELD) is a complicated and demanding problem for power engineers. ELD relates to the minimization of the economic cost of production, thereby allocating the produced power by each unit in the most possible economic manner. In recent years, emphasis has been laid on minimization of emissions, in addition to cost, resulting in the Combined Economic and Emission Dispatch (CEED) problem. The solutions of the ELD and CEED problems are mostly dominated by metaheuristics. The performance of the Chameleon Swarm Algorithm (CSA) for solving the ELD problem was tested in this work. CSA mimics the hunting and food searching mechanism of chameleons. This algorithm takes into account the dynamics of food hunting of the chameleon on trees, deserts, and near swamps. The performance of the aforementioned algorithm was compared with a number of advanced algorithms in solving the ELD and CEED problems, such as Sine Cosine Algorithm (SCA), Grey Wolf Optimization (GWO), and Earth Worm Algorithm (EWA). The simulated results established the efficacy of the proposed CSA algorithm. The power mismatch factor is the main item in ELD problems. The best value of this factor must tend to nearly zero. The CSA algorithm achieves the best power mismatch values of 3.16×10−13, 4.16×10−12 and 1.28×10−12 for demand loads of 700, 1000, and 1200 MW, respectively, of the ELD problem. The CSA algorithm achieves the best power mismatch values of 6.41×10−13 , 8.92×10−13 and 1.68×10−12 for demand loads of 700, 1000, and 1200 MW, respectively, of the CEED problem. Thus, the CSA algorithm was found to be superior to the algorithms compared in this work

    The DFT+U: Approaches, Accuracy, and Applications

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    This chapter introduces the Hubbard model and its applicability as a corrective tool for accurate modeling of the electronic properties of various classes of systems. The attainment of a correct description of electronic structure is critical for predicting further electronic-related properties, including intermolecular interactions and formation energies. The chapter begins with an introduction to the formulation of density functional theory (DFT) functionals, while addressing the origin of bandgap problem with correlated materials. Then, the corrective approaches proposed to solve the DFT bandgap problem are reviewed, while comparing them in terms of accuracy and computational cost. The Hubbard model will then offer a simple approach to correctly describe the behavior of highly correlated materials, known as the Mott insulators. Based on Hubbard model, DFT+U scheme is built, which is computationally convenient for accurate calculations of electronic structures. Later in this chapter, the computational and semiempirical methods of optimizing the value of the Coulomb interaction potential (U) are discussed, while evaluating the conditions under which it can be most predictive. The chapter focuses on highlighting the use of U to correct the description of the physical properties, by reviewing the results of case studies presented in literature for various classes of materials
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