403 research outputs found

    Study of Rice Marketing System in Iran

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    Rice comes second after wheat in Iran`s food consumption economy. Rising population and recent growth in GDP has made Iran one of the greatest rice importer countries all over the world. That is why rice marketing has always been a controversial issue in Iran`s agricultural economics. To study rice marketing system in Iran, this paper aims to calculate rice marketing margin, market efficiency and marketing cost coefficient in seaside Mazandaran province( where 70 percent of domestic rice production is obtained )Over the period 2000-2010. Results show that firstly HYV`s wholesale marketing margin is less than local varieties in 2000 while this trend is reversed in 2010. Secondly, retail marketing margin, total marketing margin, market efficiency and cost marketing coefficient for local varieties are all greater than HYV. Consequently, agricultural cooperative`s encouragement would lead to decrease in rice marketing margin and role of traders and raises rice farmers earningsMazandaran Province, Marketing Margin, Rice, Marketing, Q13,

    Shape-Controlled Nanoparticles as Effective Catalysts for Proton Exchange Membrane (PEM) Fuel Cells

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    Polymer electrolyte membrane fuel cell (PEMFC), is considered a promising candidate for the next generation power sources in transportation, stationary and portable applications. However, oxygen reduction reaction (ORR), one of the key reactions occurring on PEMFC is kinetically slow; this has limited performance and further advancement in this kind of fuel cells. Thus, improving the PEMFC efficiency requires a thorough understanding of the ORR mechanism on the desired catalyst. To address the above-mentioned demands, the scope of this thesis is focused on the fundamental understanding of facet-controlled nanoparticles, metal-support interactions, and bimetallic platinum catalysts, utilizing synchrotron-based X-ray absorption, X-ray photoelectron spectroscopy, and electrochemical characterization methods. It is found that particle size, shape, composition (Pd and Co are the other metals), and the supporting material not only can act as momentous parameters in enhancing the catalytic activity of NPs but also are functioning as vital criteria in boosting the stability

    Genomic analysis of Mycobacterium bovis and other members of the Mycobacterium tuberculosis complex by isoenzyme analysis and pulsed-field gel electrophoresis.

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    Initially, multilocus enzyme electrophoresis was used to examine genetic relationships among 63 isolates of Mycobacterium bovis and 13 other members of the M. tuberculosis complex. The isolates were divided into five electrophoretic types, with a mean genetic diversity of 0.1. The strains were genetically homogenous, indicating that members of the complex were closely related. This supported the suggestion that they should be considered as subspecies of a single species. Pulsed-field gel electrophoresis (PFGE) was then used to differentiate these isolates, as well as 59 additional isolates of M. bovis from different parts of the world. PFGE differentiated these strains into 63 patterns (53 patterns for M. bovis). Isolates of M. bovis from Western Australia (n = 46) were more homogenous than isolates from other regions. Eight strains were identified in that state, and one predominantly bovine strain was isolated from two human beings and a feral pig. Although M. bovis isolates from different parts of the world had distinct DNA patterns, some were very similar. PFGE is a highly discriminatory technique for epidemiological studies of bovine tuberculosis. For example, it allowed differentiation between isolates of M. bovis cultured from animals in separate outbreaks of tuberculosis, it suggested the transmission of infection between certain properties, and it demonstrated the existence of multiple infections with different strains at certain farms

    Modeling the Effects of a Simple Immune System and Immunodeficiency on the Dynamics of Conjointly Growing Tumor and Normal Cells

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    In this paper, we develop a theoretical contribution towards the understanding of the complex behavior of conjoint tumor-normal cell growth under the influence of immuno-chemotheraputic agents under simple immune system response. In particular, we consider a core model for the interaction of tumor cells with the surrounding normal cells. We then add the effects of a simple immune system, and both immune-suppression factors and immuno-chemotherapeutic agents as well. Through a series of numerical simulations, we illustrate that the interdependency of tumor-normal cells, together with choice of drug and the nature of the immunodeficiency, leads to a variety of interesting patterns in the evolution of both the tumor and the normal cell populations

    Chemotherapy in conjoint aging-tumor systems: some simple models for addressing coupled aging-cancer dynamics

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    Background In this paper we consider two approaches to examining the complex dynamics of conjoint aging-cancer cellular systems undergoing chemotherapeutic intervention. In particular, we focus on the effect of cells growing conjointly in a culture plate as a precursor to considering the larger multi-dimensional models of such systems. Tumor cell growth is considered from both the logistic and the Gompertzian case, while normal cell growth of fibroblasts (WI-38 human diploid fibroblasts) is considered as logistic only. Results We demonstrate, in a simple approach, how the interdependency of different cell types in a tumor, together with specifications of for treatment, can lead to different evolutionary patterns for normal and tumor cells during a course of therapy. Conclusions These results have significance for understanding appropriate pharmacotherapy for elderly patients who are also undergoing chemotherapy

    Investigation of Carbapenem-Resistant AcinetobacterBaumannii Resistance Rate in Clinical Specimens of Newborns at Imam Khomeini Hospital in Tehran

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    Background: Carbapenem-resistant Acinetobacter Baumannii (CRAB) hospital infection poses a serious threat to the health of the newborns in neonatal intensive care units (NICU). The present study was conducted to evaluate the prevalence and resistance of hospital infections in the NICU ward at Imam Khomeini hospital in Tehran.Materials and Methods: The blaOXA-51 like gene was investigated with polymerase chain reaction (PCR). Then, sensitivity of isolates to different antibiotics was assessed using disc diffusion method and broth micro dilutions to determine the minimum inhibitory concentrations (MICs). Pulsed field gel electrophoresis (PFGE) was used for typing of randomly collected CRAB infection at different wards of this hospital. Results: A total of 10 CRAB infections were isolatedduringthe6-month study period, and it was found that 100% of them were positive forblaOXA-51-like gene in PCR assay.  All  isolates were resistant to all tested antibiotics, except colistin, polymyxin B, and tigecycline. CRAB isolates had a high MIC values for imipenem, cefotaxim, and amikacin, showing multidrug resistant (MDR) phenotype. According to PFGE analysis,3palsotypes including clone A (7%), clone B (2%), and clone D (1%) were seen in the 10 CRAB isolates. Clone A was a dominant clone and spread in different wards of the hospital, especially in other ICUs and the emergency ward. Moreover, the similarity between the palsotypes showed the ability of transferring CRAB infection from different wards of the hospital to the NICU.Conclusions: Based on the results of this study, CRAB infection, with a high resistance rate, has the ability to enter into important wards such as NICU, and thus it is highly important to control the presence of these isolates in different parts of the hospital

    Drug resistance patterns of bacteria isolated from patients with nosocomial pneumonia at Tehran hospitals during 2009-2011

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    INTRODUCTION: Nosocomial pneumonia remains an important cause of mortality and morbidity worldwide. Surveillance programs play an important role in the identification of common etiologic agents and local patterns of antimicrobial resistance. METHODOLOGY: In this study we determined the frequency and antimicrobial susceptibility of pathogens isolated from patients with nosocomial pneumonia during 2009 to 2011. RESULTS: A total of 642 bacteria were isolated from 516 suspected samples. Acinetobacter baumannii (21.1%, n = 136), was the commonest isolated pathogen followed by Pseudomonas aeruginosa (17.4%, n = 112), Staphylococcus aureus (15.8%, n = 102) and enterococci (8.4% n = 54). The most effective therapeutic agents against A. baumannii were polymyxin B (95.5% susceptible), ceftriaxone/tazobactam (72% susceptible) and levofloxacin (52.9% susceptible). Polymixin B (89.2% susceptible), ceftriaxone/tazobactam (89.2% susceptible) and piperacillin-tazobactam (80.3% susceptible) were found to be the most active agents against P. aeruginosa. Extended-spectrum beta-lactamases were detected among isolates of K. pneumoniae (45.4%) and E. coli (20.3%). Overall, the prevalence of methicillin-resistant S. aureus and vancomycin resistant enterococci were 80.4% and 40.7% respectively. Linezolid was found to be the most active antibiotic against these pathogens. The etiology of 50% of the nosocomial infection cases was polymicrobial. CONCLUSIONS: The combination of ceftriaxone/tazobactam seems to be beneficial agent against multidrug-resistant Gram-negative bacilli isolated form respiratory tract infections. The results of our study can be used for guiding appropriate empiric therapy in this geographic region
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