Showing 12 results for Bazargan
Volume 10, Issue 2 (Spring 2024)
Abstract
Background: Methicillin-resistant staphylococci (MRS) are regarded as a global public health threat. Physicians are restricted in their treatment options due to resistance to aminoglycosides and tetracycline derivatives. This study investigated aminoglycoside and tetracycline derivative resistance among Staphylococcus isolates in Shiraz, southwestern Iran.
Materials & Methods: Totally, 113 staphylococcal isolates were recovered from different clinical samples in Nemazee Teaching Hospital from October 2019 to January 2020. Kirby-Bauer disc diffusion method was performed to assess the antimicrobial susceptibility of the isolates against aminoglycoside and tetracycline antibiotics. Aminoglycoside-modifying enzymes (AMEs) and tet genes were investigated among staphylococci isolates using polymerase chain reactions (PCR).
Findings: MRS prevalence among Staphylococcus isolates was 61% (69 of 113). The majority of MRS isolates were obtained from blood (39.1%; 27 of 69) and urine (17.4%; 12 of 69). The highest prevalence of MRS isolates was among emergency room patients (34.8%; 24 of 69). The highest resistance of MRS isolates was against tobramycin (59.4%; 41 of 69) and tetracycline (55.1%; 38 of 69). The prevalence of tetM and aac (6')-Ie-aph (2'') genes was significantly higher among MRS compared with methicillin-sensitive staphylococci (MSS) (87.5% vs 12.5% and 95.6% vs 6.4%, respectively) (p= .001).
Conclusion: The prevalence of MRS isolates, including methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS), was remarkable in Shiraz as the center of medical services in the southwest of Iran. Furthermore, these MRS isolates were highly resistant to aminoglycosides and tetracyclines. Therefore, antimicrobial stewardship is necessary to address health conditions.
Mohsen Amini, Majid Bazargan,
Volume 13, Issue 15 (Third Special Issue 2014)
Abstract
In this research, optimization of shell-and-tube heat exchangers with dual objectives of achieving upper heat transfer rate and lower total cost has been done by the Genetic algorithm. All geometrical constraints and standards, minimum and maximum velocity limits as well as maximum allowable pressure drops are considered in optimization process. Relations between the objective functions and optimization variables have many complexities so that the gradient approach employed by many optimization algorithms may not be adequate. Special care has been taken in employing Genetic algorithm to assure that the optimized values of variables are not trapped in local optimum domains. To evaluate the precision of computer code of current study, a comprehensive case study has been considered. The optimization has been accomplished by considering 11 variables. In a next attempt the mass flow of cooling fluid, which is the sea water in the case under study, has been added as the 12th variable. The obtained Pareto plots show that the optimized parameters suggested by this study provide upper heat transfer rate and simultaneous lower total cost relative to available results.
Ali Esfandiari, Majid Bazargan,
Volume 14, Issue 2 (5-2014)
Abstract
Due to growth of energy consumption and depletion of fossil fuels sources, power generation of renewable energy sources such as wind energy has become one of the main interests of researchers. Among different types of wind turbines used for extracting electric power from wind flow, vertical axis wind turbines can be implemented in urban areas and in proximity of energy consumers because of their independence of wind direction, low sensitivity to wind turbulence and lower noise production. In this paper a straight-bladed vertical axis wind turbine has been simulated 3 dimensionally by use of a commercial CFD code. The numerical results have been validated against available experimental data. To improve the performance of the turbine, the effects of blade mount point offset and preset pitch have been investigated. The results show that appropriate blade offset and preset pitch for this case study leads to a 60 and 65 percent increase in the maximum performance coefficient respectively.
Volume 14, Issue 5 (especial summer- 2014)
Abstract
Freeways have a particular role in urban transportation networks due to their high capacity compared to other facilities of lower hierarchical classification. Although these facilities do not have any at-grade junctions and are of the highest mobility and least access classification, their flow control can help general urban traffic condition. Traffic control strategies are thus of particular importance to urban transportation. Ramp metering of urban freeways and highways is one of the efficient traffic control policies that can alleviate traffic congestion by restricting on-ramp flows to the main stream. A main challenge of this policy is the determination of optimal flow rates of the on-ramps leading to optimal flow rate of the main stream. In this paper, a linear programming model is developed considering the capacity constraint of the main stream and the constraints of queue length of ramps. Although the queue length of the on-ramps increase due to the ramp metering strategy by holding up vehicles on these ramps, the travel time of the main stream as the main body of traffic whose traffic condition is of higher importance, decreases due to the increase in the speed of this stream caused by the drop in vehicle density. The main objective of this paper is the implementation of a mathematical programming model developed for a rather congested case study in Tehran; and the analysis of its challenges and impacts. This model takes into account the maximization of flow in the transportation network while flow conservation and capacity constraints are not violated. In the field survey, flow rate data of about 15000 vehicles west-bound of Shahid Hemmat highway segment from Modares freeway to Shahid Chamran off-ramp were gathered for three hours. This segment includes five on-ramps and four off-ramps whose flow rate data along with that of the main stream was collected on a Tuesday in summer 2011. The data was collected through video recording and then obtaining the necessary variables like flow rate data by re-watching the films carefully and counting the vehicles. Although very time and budget consuming, but this survey method made possible the data collection phase to be valid and reliable. Flow rates for 5 minute time intervals for all the ramps and the main stream were obtained to comprise part of the research data base. Capacity, as a model parameter, was predicted for the segment under study. Results of the mathematical programming optimization model indicate that level of service of the segment under study increases from F to E and that the speed in the main stream increases between 18 and 24 kilometers per hour and that travel time in this segment has a decrease of nine minutes. Results of the optimization model indicate that freeway traffic performance can be optimized by careful management of on-ramp monitoring and control realized through ramp metering strategy, emphasizing quantitatively and scientifically the importance and necessity of detailed traffic data and its analysis for the betterment of traffic conditions through merely management techniques which do not require much time or budget to use the existing facilities more efficiently. .
Madjid Soltani, Hossein Bazmara, Mostafa Sefidgar, Madjid Bazargan, Seyyed Mojtaba Musavi Naeenian,
Volume 14, Issue 7 (10-2014)
Abstract
Tumor induced angiogenesis is the bridge between benign and malignant tumor growth stages. In this process, growth and migration of endothelial cells build capillaries to supply the tumor with blood for its further growth. Regarding the importance of capillary formation and blood flow in angiogenesis, simulation of this phenomenon plays important role in tumor growth and cancer development studies. In this work, considering intracellular, cellular, and extracellular scales a mathematical model of tumor-induced angiogenesis is used to consider mechanical effects of extracellular matrix on growth and migration of endothelial cells. These effects are matrix density and its fiber length. In this study, to model cellular dynamics, a discrete lattice based Monte Carlo method is used. Results show that migration of endothelial cells and development of capillaries are possible in a specified range of matrix density and matrix fiber length. Based on the results, medium matrix densities and low fiber length provide a suitable environment for capillaries growth and development. The model is a promising tool for modeling tumor induced angiogenesis and is a base for development of models for loop formation and blood flow in capillaries around tumor.
Mostafa Sefidgar, Hossein Bazmara, Majid Bazargan, S. Mojtaba Mousavi Naeenian, Madjid Soltani,
Volume 14, Issue 9 (12-2014)
Abstract
Nowadays, solid tumor modeling and simulation results are used to predict how therapeutic drugs are transported to tumor cells by blood flow through capillaries and fluid flow in tissues. This model involves processes such as fluid diffusion, convective transport in extracellular matrix, and extravasation from blood vessels. In this paper, a complete model of interstitial fluid flow in tumor and normal tissue is presented with considering multi scale of solution such as blood flow through a capillary (as the smallest scale) to interstitial flow (as the biggest scale). The advanced mathematical model is used to generate a capillary network induce by tumor with two parent vessel around the tumor for the first time. In the following, the blood flow is modeled through the network with considering the non-continuous behavior of blood rheology and adaptability of capillary diameter to hemodynamics and metabolic stimuli. This flow is simultaneously simulated with interstitial flow which is coupled to blood flow through capillary with extravascular flow. The results predict elevated interstitial pressure in tumor region and heterogeneous capillary network which are introduced as barriers to drug delivery.
Volume 16, Issue 1 (Spring 2016 2016)
Abstract
Trade balance is regarded as both main macroeconomic factor and strategic constraint in developing countries. Exchange rate, which is defined as parity relationship between national currency and foreign currencies, is a vital determinant of countries’ trade balance. As the real effective exchange rate measures the changes in prices and relative costs by a common currency, it is the most popular indicator to measure competitiveness.
On one hand, fluctuation of this index represents disequilibrium in the economy, and on the other hand, it is the cause of more instability. Since the direction and size of the effects of real exchange rate on trade balance is an important macroeconomic issue, this articleinvestigates the real effective exchange rate changes on trade balance in Iran and its’ major partners using the Vector Error Correction Model ( VECM ) over the period 1993-2011. The results indicate that the real effective exchange rate volatility reduces trade balance only for Germany in the short run and rises it for Italy in the long run.
Mostafa Varmazyar, Majid Bazargan, Arsh Moahmmadi, Alireza Rahbari,
Volume 16, Issue 12 (2-2017)
Abstract
In this study, a Lattice Boltzmann Method (LBM) has been developed to calculate the distribution of a scalar quantity, like temperature, in a natural convection flow field under the condition of varying fluid thermal conductivity. The standard form of an LBM usually considers the fluid properties to be constant without any source term in conservation equations. The model developed is to account for variation of thermal conductivity with temperature in the presence of an external heat source. The proposed model has been examined against various case studies. It is shown that it is capable of modeling the extremely nonlinear problems. To magnify the nonlinear term in the natural convection case of under study, the radiation and other thermal sources have been used. The multiple relaxation time scheme has been applied to assure the solution stability. Using Chapman-Enskog analysis, the error associated with the proposed model has been estimated. The part of error which was not due to variations in the fluid properties, may be eliminated by introducing a correction term in higher order terms in Chapman-Enskog analysis. In addition, it has been shown that the correction term associated with the fluid conductivity variations, create an error of second order in terms of Knudsen number and is negligible. The present LBM model has an error of the second order of magnitude with respect to time.
Mostafa Varmazyar, Majid Bazargan,
Volume 17, Issue 5 (7-2017)
Abstract
Piston effect is an important mechanism of heat transfer in a supercritical fluid flow under microgravity condition. In this study, a Lattice Boltzmann Model (LBM) has been introduced to simulate the piston effect. Variations of diffusion coefficient has been accounted for by adding a corresponding term to equilibrium distribution function. To calculate the intermolecular forces and compressibility in the LBM, a van der Waals equation of estate has been employed. Boundary conditions corresponding to compressible LBM at the presence of van der Waals forces have been set to eliminate the speed jump at the wall. It has been shown that such boundary conditions provide high accuracy in problems involving forces with an error of second order of magnitude in terms of space. The developed thermal LBM together with compressible LBM have been applied to simulate the heat transfer to supercritical fluid flows. The piston effect has been modeled by considering van der Waals inter molecular forces. The errors associated with each of the schemes used have been evaluated. A comparison between a pure conduction case and heat transfer due to piston effect has been made. It has been shown that the heat transfer occurs faster once the piston effect is in effect.
Volume 20, Issue 137 (July 2023)
Abstract
Shelf life increasing of red meat has the great importance due to its perishable properties and consumers' demand to use food free synthetic preservatives. This study was aimed to investigate the antimicrobial and antioxidant effects of poly lactic acid film (PLA) containing different concentrations of ethanolic sumac extract (SE 1 and 3%) and copper oxide nanoparticles (CuO1 and 2%) on shelf life enhancement of the minced beef during cold storage. The samples were stored at 4 ± 1 °C for 12 days and analyzed at 0, 1, 3, 6, 9 and 12 days of the storage period. All of the treatments significantly (P≤0.05) decreased total viable count, psychrotrophic bacteria and Enterobacteriaceae spp. population as compared control group during the storage period. Total volatile basic nitrogen (TVB-N) and pH values of the non-packed samples (control) were significantly (P≤0.05) higher than the packed ones during the storage time. The combined treatments containing SE and CuO-NPs showed the highest efficiency in shelf life increasing of the cold stored minced beef in dose dependent manner. Based on the results, it can be concluded that the usage of biodegradable poly lactic acid film containing a complex of SE and CuO-NPs is effective packaging in the shelf life improvement of minced beef during 12 days of the refrigerated storage period.
Volume 23, Issue 3 (Fall 2019)
Abstract
Introduction
Among the various subjects, historical and cultural elements are among the factors influencing the formation of the city's identity. However, some of these elements, while maintaining their function, are considered as an active ingredient in the city's atmosphere as well. Hence, in addition to the "heritage value", they have "functional value". Also, along with the functional value of these elements, the method of gathering and deploying them should not be left out of view. This suggests that in a certain area of the city, how many valuable elements are deployed and how they affect each other. Regardless of the need to plan for these valuable elements, only attention to their physical and physical dimensions is not important. But besides that, the issue of their work and their distribution pattern should be considered. However, this is the subject in many ways in interfering with worn-out tissues such as recreation, rehabilitation, and so on. In other words, it does not make clear what the difference in type of entry and planning for the mentioned patterns should be considered. Hence, personal effects are seen in the context of any of the interventions in the worn out tissues faced with these elements. On the other hand, in the current context, the projects developed for these emphasis on highlighting their physical value.
The study seeks to demonstrate the "amateurish approach" to face-to-face value identity collections in urban textures (both worn and non-worn). How does this approach, while emphasizing inclusiveness, does not ignore Ryan's details? On the other hand, these collections are considered in the form of a coherent whole, and, in the shadow of such a look, it seeks to integrate and enhance the collection. Such an approach has been less considered in urban studies in dealing with historical and active collections. Therefore, the study can be considered as one of the first research activities in this field.
Methodology
Research methodology this study is based on descriptive and analytical methods and quantitative and qualitative methods was applied. The use of reasoning methods of analogy and induction is the basis of the work in this study. In this way, using the logic of induction and review of each user of Shariati high school (including 470 students), their daily distance from home to school and vice versa was determined. This step was carried out using GIS and the creation of a database of all students' residence locations, using network analysis methods and standardized distance. Also, in this section, the type of travel means of each student and the amount of travel they generated to this area was determined. For this purpose ArcGis and SPSS software were used. On the other hand, based on the method of analogy, the study of the documents and resources related to land use and its adaptation to the city's space and areas with valuable elements, was designed to develop a theoretical model. Then, while adapting the results of moving and moving students in the area of Shohada Square, the theoretical model, identified the procedures and the results of this adaptation, and, while discussing and analyzing, suggestions were made.
Research variables include the amount of student's passing, the student's transfer, the position of the valuable elements within the shohada area, as well as the "words and names" of the valuable elements located within the martyrs field in order to find their place in the field of social justice. Is.
Result and discussion
The results of this study indicate the role of "the function of these elements" in shaping its disadvantage. In particular, the use of inductive reasoning and the use of "standard distance" and "network analysis" models from the displacement of 470 high school students in Shariati showed that a daily 3800 km journey in a 6 km radius (More than 3 times). This study, which clarifies the continuity of "elemental function", has, on the one hand, fostered identity and, on the other hand, congestion and reduced environmental quality. An approach based on these dimensions, balances the criterion in order to achieve coherence in relation to the "function of elements".
Conclusion
Therefore, according to the key points obtained, the confrontation and dichotomy of identity enhancement / degradation in the area of martyrs can be viewed from the perspective of (1) the evaluation of the results of the function of valuable elements (such as Shariati high school) in the area of the martyrs, and (2) To evaluate the pattern of the master plan for the area, as follows.
1) Examining the results of the function of valuable elements (such as Shariati high school) in the area of the Shohada Square: It can be said that part of the traffic and busy area of the Shohada Square, as a result of the activities of its valuable elements such as Shariati high school. This bustle has degraded the quality of the environment.
2) Evaluation of the master plan pattern for the shohada area: The findings of the study showed that in Mashhad's comprehensive plan to improve the status of this area, two important issues were considered: 1) improving the identity of the complex; and 2) reducing congestion and congestion.
Volume 24, Issue 3 (5-2022)
Abstract
This study aimed to assess the effect of incubation time and sewage sludge on peppermint biomass, essential oil yield, and Zinc (Zn), lead (Pb), and Cadmium (Cd) concentrations in the plant tissues as well as assessing phytoremediation potential of peppermint grown in contaminated calcareous soils. A greenhouse experiment was conducted by growing peppermint (Mentha pipertia L.) in two contaminated soils treated with three levels of sewage sludge (0, 10, and 30 g kg-1) over two incubation times (30 and 120 days). Results revealed an increase in plant biomass and essential oil yield with an increase in incubation time and the sewage sludge amount. The concentrations of Zn, Pb, and Cd in plant tissues increased significantly in all treatments, except Cd concentration in plants growing on 10 g kg-1 of sewage sludge and incubated for 120 days. No traces of Zn, Pb, and Cd were found in essential oil of plants treated with 10 g kg-1 of sewage sludge. In other treatments, the concentrations of these metals in the essential oil were found within the limits recommended for medicinal plants. Unlike the bioaccumulation factor, the translocation factor of the studied metals decreased with an increase in the sewage sludge amount and incubation time. Although peppermint was not a sustainable plant to lower the pollution load, as the biomass production increased significantly and metals concentrations in essential oil remained within the recommended limits in all treatments, it can be concluded that peppermint can be used for cultivation in contaminated soils treated with sewage sludge.
