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Abstract

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Background: The escalating prevalence of multidrug-resistant (MDR) commensal intestinal bacteria characterized by extended-spectrum β-lactamase (ESBL) production is an alarming global health threat. Drug users have been introduced as a major source of antibiotic-resistant bacteria, possibly due to drug abuse. The present study aimed to investigate the potential factors related to fecal carriage of MDR ESBL-producing intestinal Escherichia coli (E. coli) in drug users in the southwest of Iran.
Materials & Methods: In this cross-sectional study, stool samples of 109 drug users were collected and cultured. After the biochemical confirmation of E. coli isolates, the antimicrobial resistance pattern and ESBL production of the isolates were determined. Then logistic regression analysis was conducted to determine possible factors related to fecal carriage of MDR ESBL-producing intestinal E. coli.
Findings: Logistic regression analysis indicated that increasing age and duration of addiction were associated with increased risk of MDR ESBL-producing E. coli carriage in the intestinal flora of drug users (p< .05). Moreover, oral drug use compared to the smoking method led to a higher carriage rate of MDR ESBL-producing E. coli in the intestinal flora of drug users (p< .05). Also, self-employed drug users compared to those with fixed public occupation showed higher rates of MDR ESBL-producing E. coli carriage in their intestinal flora (p< .05).
Conclusion: Age, duration of addiction, method of drug use, and occupation were significantly associated with MDR ESBL-producing E. coli colonization.

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Aims: The aim of present study was production of Fatir bread fortified with rainbow trout and silver carp meats and evaluation of its quality attributes during room temperature storage.
Materials & Methods: Different concentrations of cooked rainbow trout and silver carp meat (5, 10, 15, 20 and 25%) were added to the Fatir bread and sensory properties of prepared bread were measured. Then, selected treatments were stored for 9 days at room temperature and during this time the quality attributes were evaluated. 
Findings: Results of initial sensory evaluations were showed that the Fatir bread containing 5% of rainbow trout and 10% of silver carp were accepted. Results also demonstrated that the protein, lipid and moisture content of the bread were increased with addition of the fish meat. Fatir bread fortified with fish meat had higher TVB-N, peroxide and total viable bacteria during room storage period. In terms of flavor index, the control Fatir bread was acceptable until the end of the storage period, however, the breads fortified with fish meat were within the acceptable range until day 5.
Conclusion: Can be concluded that although fortified breads showed higher nutritional value, they had lower shelf life than control bread. Between fortified breads, the quality changes were lower in the bread containing rainbow trout meat.    
 

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Due to low surface energy and hierarchical roughness, fluids on superhydrophobic surfaces are mobile. The slip velocity on these surfaces is formulated using Navier’s slip length. On regular surfaces, slip length is only a few nano-meters. On superhydrophobic surfaces, slip length can be as large as 500 µm. Literature studies usually make the entire surface superhydrophobic which may not be the optimum situation. To find the desirable regions, the problem should be analyzed numerically. Most of the numerical studies are for flat plates. On curved surfaces (e.g. foils), due to the adverse pressure gradient and possibility of separation, analysis is more complicated. Here, the effect of using superhydrophobic surface for a SD7003 hydrofoil is studied numerically and at different Reynolds numbers and slip lengths. The flow pattern is considered laminar, incompressible and isothermal and a hydrofoil made of aluminum with a chord length of 10cm is selected. Results of the shear stress, pressure coefficient and the drag coefficient on the typical boundary condition were compared with the case of slip boundary condition. It was found that by increasing the slip length, the drag coefficient decreases. It was also found that the effectiveness of using superhydrophobic surfaces in decreasing the drag coefficient improves at higher Reynolds numbers. By increasing the Reynolds number from 4.5×〖10〗^4 to 7.5×〖10〗^4 and at the slip length of 50 µm, the drag coefficient reduction increases from 0.7% to 7%.

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Small scale hydraulic power plants equipped with very low head (VLH) axial turbines can be considered as a novel approach to extract energy from rivers and canals. In this study, design process and numerical simulation of a prototype of a VLH turbine is done. The selected turbine generates 450 kW power at the head of 2.6 m. In order to generate the turbine geometry using MATLAB and X-Foil, a computational code has been developed. The design process to generate finalized geometrical data of the runner blades contains a primary hydrodynamic design using Euler equation in turbomachinery, a classical approach for axial turbomachinery design and selection of hydrofoils with appropriate lift coefficient. Using the geometry and structured mesh generated by Turbo Grid for discretization of governing equations, the numerical simulation was accomplished by ANSYS CFX. Simulation results of different opening angles of the runner blades are presented for the turbine system including runner and guide vanes. Also, cavitation possibility is studied in various opening angles and discharges. The results demonstrate that the hydraulic efficiency of the VLH turbine is approximately 89% where the opening angle of the runner blades is at the design point. Moreover, cavitation does not occur at the design point. However, at flow rates larger than the nominal flow rate, and at opening angles larger than the design point cavitation at the leading edge is possible

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Dynamic motion of a 2D SD7037 airfoil is investigated numerically in presence of a slip boundary condition. The dynamic motion of the airfoil is a harmonic oscillation, where the frequency and the amplitude of oscillations were adequate to airfoil to undergoing dynamic stall phenomenon. Dynamic stall occurred when the dynamic motion of the airfoil causes dynamic stall vortices, resulting in leading edge and trailing edge vortices which lead to rising the aerodynamic loads significantly. Analyzing the phenomena is challenging especially when a slip boundary condition exists near the airfoil wall. This particular condition is the general property of super-hydrophobic surfaces. These surfaces could potentially prevent the blade from icing. The main characteristic of these coatings is the appearance of a slip velocity on the wall. The slip velocity can affect the airfoil aerodynamics which is the main purpose of this paper. In this regard, a 2D airfoil with the Reynolds number of Re≈4×〖10〗^4 is analyzed using computational fluids dynamics (CFD). The Transition-SST model is applied. The results showed that not only the slip condition affects the aerodynamic loadings, but also the dynamic stall regimes changed considerably. So that for slip lengths higher than 100 micrometers, the maximum magnitude of the lift coefficient damped by 16%.

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