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Showing 6 results for Falsafi


Volume 7, Issue 4 (2-2018)
Abstract

The key role of public infrastructure projects in promoting GDP growth and country development achievement as well as huge amount of investment needed for them, has multiplied the importance of effective and efficient implementation of them. Successful management and desirable value creation of these projects aligned with public interests, depends on good governance of multiple projects level which named “project portfolio”. Utilizing the principles of good governance at this level leads to portfolio performance improvement and results such as optimum projects resource allocation aligned with the organization's strategic requirements. But applying such a governance in the complex public sector, faces more barriers than private sector. Identifying and analyzing these barriers, pave the way for designing appropriate governance models. To accomplish this, 18 experts with 15 to 25 years of experience in key positions influencing on infrastructure portfolios governance were interviewed whom selected by purposeful sampling. This qualitative study is a practical-developmental research done with phenomenological methodology. Required data were collected through semi-structured interviews and then analyzed. According to findings, the barriers to road infrastructure project portfolios good governance categorized in five groups including: behavioral barriers, organizational barriers, credit barriers, macro structural barriers and macro strategic barriers drawn into a pattern of three-tier structure.



Volume 7, Issue 4 (Fall 2021)
Abstract

Backgrounds: Streptomyces is an aerobic filamentous Gram-positive bacterium frequently found in various environments worldwide. Cellulases are a group of glycosyl hydrolase enzymes that are frequently produced by bacteria. Thus, the aim of this study was to detect cellulase-encoding gene (celA) in soil-living Streptomyces strains and evaluate its cloning in Escherichia coli Origami strain.
Materials & Methods: Soil samples were collected from a depth of 5-10 cm in Tehran, Iran. After identification of Streptomyces isolates by morphological and biochemical tests, genomic DNA was extracted. Polymerase chain reaction (PCR) test was employed to identify Streptomyces strains harboring the cellulase gene. The celA gene was positively transmitted to the host bacterium E. coli via a vector and cloned through the TA technique. Real-time PCR was used to measure the overexpression of this gene. ClustalX and Mega5 software were used to draw the phylogenetic tree.
Findings: Out of 12 Streptomyces isolates, 25% were found to carry the celA gene. After cloning the celA gene, the cloned strains were chosen by colony selection (blue/white). The real-time PCR test showed the expression of the celA gene in the transformed strains. Phylogenetic analysis results using the neighbor-joining assay showed that Streptomyces spp. with 81% bootstrap were located in the same clade, indicating their close relatedness.
Conclusion: Soil is one of the high-potential sources of the production of secondary metabolites, which could be used as a valuable source of various biological products such as cellulase.
Mohadeseh Farnaghizad, Yasaman Issazadeh, Sarvenaz Falsafi, Ava Behrouzi,
Volume 14, Issue 3 (2-2024)
Abstract

 
Pseudomonas aeruginosa is one of the most important causes of infection in medicine, which in recent years is known as an antibiotic resistant bacterium. One of the antibiotic resistance strategies of this bacterium is algD and PpyR genes expression for biofilm formation.
 In recent years, it has been shown that using microorganisms, such as probiotics, is a method of pathogen bacterium harnessing, hence, in this study, for preventing biofilm formation of P. aeruginosa, E.coli Nissle 1917(EcN) probiotic bacterium is used, as a new treatment choice.
Due to direct relationship between antibiotic resistance and biofilm formation, strains with the    
highest antibiotic resistance was chosen by antibiogram test. Then, in order to determine the inhibition rate of EcN bacterium in the formation of biofilm caused by P. aeruginosa bacterium, a biofilm formation test was performed.
At the end, to evaluate algD and PpyR genes expression, which were key parts of biofilm formation, in the presence of probiotic EcN bacterium, Real- time PCR method was used.
Based on the results of the biofilm formation test, EcN bacterium showed a high inhibitory effect on the formation of biofilm caused by P. aeruginosa bacterium.
.Also, in assessment of algD and PpyR genes expression in presence of EcN probiotic, a significant reduction in PpyR gene expression has been seen, in comparison with control group. The results of this study showed that EcN probiotic can act as a suitable new treatment option, to reduce P. aeruginosa biofilm formation.



Volume 15, Issue 6 (8-2015)
Abstract

This numerical study forced convective heat transfer ferrofluid within a circular copper tube includes portions of the electromagnetic isolation under an alternating magnetic field is performed. Laminar flow through a tube under uniform and thermal flux passes. Intensifying transfer of particles and velocity increase in the boundary layer using nanoparticles to increase the effect of magnetic field onto more heat transfer, the main goal is. Convection regimens resulting from complex interactions between magnetic nanoparticles were studied under different conditions, with the concentration and volume of different the heat transfer process under different frequencies of the applied magnetic field were studied. Magnetic field effects on the convective heat transfer coefficient at different Reynolds numbers and volume percentages have been studied. Also when the electromagnetic is insulated pipe parts of have been studied and have been compared with the modes without insulation. Increase the frequency and volume fraction of magnetic field, resulting in increased heat transfer were better. Magnetic field at low Reynolds numbers have shown a greater impact. For prove the numerical results evaluated in this research work has been studied experimentally. The results showed that the modeling data were in very good agreement with experimental data.

Volume 15, Issue 85 (3-2019)
Abstract

In this research the production of resistant starch (RS) from normal corn starch using heat moisture treatment (HMT) in combination with ultrasound assisted acid hydrolysis (HMT-USAH) or conventional acid hydrolysis (HMT-AH) was studied. USAH was carried out as follow: starch sample was suspended in 10% citric acid for 45 min at 45 ̊C under sonication (400 W, 20 kHz). AH starch was prepared similarly while no sonication was applied. Subsequently, USAH, AH and native starch were heat moisture treated at 120 ̊C at 30% moisture content for 8 hours. Resistant starch content of starch samples were increased from 8.3% in control sample to 13.2, 21.4 and 36.8 for HMT-native, HMT-AH and HMT-USAH samples. HMT-acid hydrolysis methods reduced the swelling power and gelatinization enthalpy of starch samples while, solubility, oil absorption, emulsion stability and gelatinization temperatures were enhanced. X-ray diffraction results revealed that HMT-USAH didn’t change the diffraction pattern of native starch.

Volume 23, Issue 3 (Summer 2020)
Abstract

Introduction: The invA gene plays a critical role in the pathogenicity of Salmonella infantis. Marine organisms, including sea cucumbers due to their effective secondary metabolites, have been identified and studied with compounds with antioxidant, anti-cancer, antibacterial and anti-inflammatory properties. The aim of this study is to determine effect of sea cucumber extraction (Holothuria leucospilota)  on S. infantis invA gene expression .
Material & Methods: Poultry meat was sampled. The S. infantis strains containing invA gene were isolated. The Hexane extract was extracted from sea cucumber colon tissue. Its effects on S. infantis and its effect on gene expression were investigated by MIC and Real-time PCR, respectively.
Results: Morphological and biochemical characteristics of these bacteria were confirmed. From 450 samples, 12 S.infantis isolates were isolated. The PCR technique was used to identify the invA encoding gene. All 12 isolates have invA virulence genes. MIC was determined 256 µg/ml. The effect of sea cucumber extract on invA gene expression in S.infantis was evaluated, and the rate of change for the invA gene is estimated -1.21.
Discussion & Conclusion: According to our results, hexane extract extracted from the sea cucumber (H. leucospilota) caused reduction ofinvA gene expression in salmonella infantis. So, it can be used as a therapeutic supplement against S. infantis

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