Showing 22 results for Rashed
Volume 2, Issue 3 (8-2017)
Abstract
This article examines the common approaches of famous Rezafi and Farokhi Yazdi to the political and social freedom of expression, freedom of thought, press freedom, and the freedom of workers and peasants through an analytical descriptive method based on the American School of Comparative Literature. The most important results of this article are that both poets devote their poetry to the liberation and liberation of the people in the form of tyranny, and have followed ethical issues in this regard, although Farrokhi Yazdi's insistence on freedom is more than the famous one.
Volume 4, Issue 3 (9-2018)
Abstract
This study is aimed to explore the fauna of grasshoppers and locusts (Orthoptera) within the county of Dasht-e Azadegan (Khuzestan Province), where is placed a vast plain with geographical coordinates of 47°42′ to 48°28′ E and 31°24′ to 32°57′ N. Sampling carried out since March 2015 until end of August 2016 using insect sweeping net and also light torch at eleven selected sites and continued for the duration of all seasons of each year every one month. The collecting sites were selected to cover the whole area in terms of climate, sea level, and vegetation. Referring to morphological identification keys and comparing the result with the type of material deposited at Hayk Mirzayans Insect Museum, out of 1770 specimens, four Families, 11 Subfamilies, 21 genera and 25 species enlisted. Out of which, one genus, and two species were discovered to be new to the fauna of Iran. Based on the yielded statistics, Aiolopus thalassinus is candidates as the most frequent species in the area.
Volume 4, Issue 3 (fall 2023)
Abstract
Objectives: In the last decade, public health planners have faced challenges related to the aging rate and the increase in mental health disorders. Research has shown that mental health issues are prevalent among older adults in Qazvin, but there hasn't been a comprehensive study on the impact of the social and built environment on mental health. Therefore, this research aims to identify the physical and social environment characteristics that can influence mental health.
Methods: This study is a cross-sectional quantitative research utilizing common mental health assessment tools, such as HADS and PSS, to gather data from 361 Qazvin's historical context residents. Additionally, an environmental quality questionnaire was used to collect information on the physical and social environment of the neighborhood. The collected data was analyzed using SPSS-25 software and the hierarchical regression method.
Results and Conclusion: The data analysis revealed that individual, place, and socio-cultural factors played a significant role in determining the mental health of older adults in Qazvin City. The individual factors that affected mental health included age, gender, home ownership status, and marital status. The place factors that influenced mental health included satisfaction with the place, land use, quality of residence, security, walkability, and access to green spaces. The socio-cultural dimension also played a role in mental health, as factors such as social support and cultural activities impacted the well-being of older adults. The results of this study can help in planning and designing neighborhoods in a historical context to improve mental health.
Volume 8, Issue 2 (10-2017)
Abstract
Cellulase is one of the industrial enzymes which its production and utilization is increasingly taking into consideration due to global heed to second-generation bioethanol production. Cellulase produced by different organisms such as fungi, bacteria, insects, and plants. With increase in utilization of this enzyme and need for reduction in the enzymes price for production of second-generation bioethanol, the production of recombinant enzyme has been considered noticeably.
In this study, by investigation of corn steep liquor as nitrogen source and second carbon source after glycerol, a new medium is designed based on SYN6 salt medium then biomass and endoglucanase II production by methylotrophic yeast was optimized. Experiments designed by one-factor and response surface methodology used for optimization.
Results showed that optimum conditions for biomass and endoglucanase production are 5.5% (w/v) and 6.15% (w/v) of corn steep liquor respectively. New optimized conditions increased 41.4% and 69.7% for biomass and recombinant enzyme production respectively.
Volume 9, Issue 2 (Spring 2018)
Abstract
Aims: The effect of crude oil pollutants on water and soil pollution and ecological changes has resulted in several studies on the identification and removal of these pollutants. The biological methods have been highly regarded for controlling this type of pollution due to their optimal performance. The aim of this study was the comparative assessment of crude oil biodegradation by Acinetobacter Calcoaceticus RAG-1 in the presence and absence of biofunctional magnetic nanoparticles.
Materials and Methods: In this laboratory research, the amount of degradation of N-decane and Hexadecane were studied, as indices of normal paraffins in crude oil pollutions, by Acinetobacter Calcoaceticus RAG-1 in the optimal conditions, which Emulsan produced. Also, the effect of magnetic nanoparticles of iron oxide coated with two layers of Decanoic acid on the degradation was investigated separately. The independent t-test was performed to examine the significance of the model parameters and the two-way ANOVA was used to examine the goodness of fit. The experiment was done with a fractional factorial design. For statistical analysis of the results, Minitab V.16 software was used.
Findings: The biodegradation of N-decane and Hexadecane were obtained 85% and 86%, respectively, after 60 days. The presence of nanoparticles also led to an improvement in the biodegradation process and an increase of 91% and 89%, respectively.
Conclusion: Acinetobacter Calcoaceticus RAG- succeeds in eliminating paraffinic compounds from crude oil with medium chain length. The effect of presence of nanoparticle in the biodegradation of N-decane is greater than that of Hexadecane.
Volume 9, Issue 2 (Spring 2018)
Abstract
Aims: Today, crude oil is one of the main sources of energy. The combustion of sulfur-containing compounds in fossil fuels leads to the production of sulfur oxides that has adverse effects to human health and the environment. At the moment, the current method for removal of sulfur is Hydrodesulfurization. The aim of this study was to investigate the effect of magnetic nanoparticles and modified carbon nanotubes as nano-adsorbent on improving the biodesulfurization activity of microorganisms (Rhodococcus erythropolis IGTS8).
Materials and Methods: In the current experimental study, the nanoparticles were synthesized by chemical co-precipitation and the carbon nanotubes were initially carboxylated. Multi-layer carbon nanotubes were mixed with 95% sulfuric acid and 52% nitric acid (volume ratio 1:3) and, then, modified by polyethylene glycol. In order to characterize nanoparticles and carbon nanotubes, scanning transmission electron microscopy (STEM), X-ray diffraction, magnetic surveys, analysis of arch Raman, and fourier-transform infrared spectroscopy (FTIR) were conducted.
Findings: The size of nanoparticles was estimated to be 7-8nm and modified carbon nanotubes showed the highest solubility as well as stability in deionized water for two weeks. The growth of microorganisms in the presence of magnetic nanoparticles and carbon nanotubes compared to their absence increased by 40% and 8%, respectively. Moreover the desulfurization activity of microorganisms in the presence of magnetic nanoparticles and carbon nanotubes showed a significant increase compared to their absence.
Conclusion: Nanoparticles with adsorption of sulfur compounds increase their availability for microorganisms.
Volume 9, Issue 3 (Summer 2018)
Abstract
Aims: Hepatitis B is a viral infection, which can cause serious liver problems. Hepatitis B surface antigen (HBsAg), which is produced as recombinant, is used to produce the Hepatitis B vaccine. The aim of this study was to detect DNA aptamer with high affinity against HBsAg by Systematic Evolution of Ligands by Exponential Enrichment (SELEX).
Materials and Methods: In the present experimental study, SELEX method was used to isolate and sequence a DNA aptamer with high affinity against HBsAg. The affinity of this monoclonal nucleotide sequence was calculated by fluorimetric method. The difference of initial absorption and residual value as a measure for the number of associated sequences were calculated with Prism 5 software by nonlinear regression method, Binding-saturation and one site-total model were performed, and the amount of electron affinity (Kd) was determined.
Findings: After performing the SELEX procedure and evaluating the amplified sequence with agarose gel, the result was positive control sample containing a bond in the range of 72nucleotides, indicating successful amplification of the selected sequence, using selective primers. During cloning steps from existing colonies of PCR reaction with aptamer specific primers, the presence of aptamer was confirmed in Escherichia coli bacteria. The reported aptamer had a stable secondary structure with a free energy of ΔG of less than -6.9kJ and Tm higher than 45°C.
Conclusion: The selected DNA aptamer has a high affinity to the target protein (HbsAg) and can be considered as an alternative for mAbs in chromatography column.
Volume 10, Issue 4 (Winter 2022)
Abstract
Comparative literature is an academic field dealing with the critical study of the literary relations between nations that, sometimes, are manifested among the fictional masterpieces of the world. One of these masterpieces is the novel Animal Farm by George Orwell, an English novelist and essayist who skillfully expressed his desired political situation and social themes in allegorical language in the novel and influenced the literature of other countries in various ways. Among the world-famous novels translated into different languages is Zayni Barakat, written by the Egyptian writer Gamal al-Ghitani and published a few decades after Animal Farm. The subject matter of the two novels is the occurrence, deviation, and hypocrisy of the rulers of the revolution but the main question is what thematic similarities there are between these two novels. The results of this research indicate that the two novels have thematic similarities in eight aspects: realization of revolution, explanation of laws, autocracy of leaders, establishment of repressive forces, populism, suppression of opponents, use of religion as a tool, and finally, transformation of revolution. Based on the American comparative literature approach and a descriptive-analytical method, this study tries to present a comparative analysis of the two novels.
Volume 11, Issue 1 (Winter 2025)
Abstract
Aims: Multiple sclerosis (MS) is a prevalent central nervous system (CNS) disorder characterized by inflammation and demyelination of nerves. The incidence of this disease has markedly risen in diverse regions, including the Middle East. Any factor that alters the quality and quantity of immune system components or influences the migration of immune cells toward the CNS may contribute to MS development. Evidence suggests that paragenetic, genetic, and environmental factors may be involved in increasing MS risk. This study aimed to investigate the effect of various infections on MS incidence.
Materials & Methods: This study included 475 MS patients and 260 healthy individuals from the Azeri population of East Azerbaijan province. Both groups filled out a questionnaire about their history of exposure to specific pathogens and infections before the age of 15.The relationship between a history of various infections and MS risk was examined.Findings: Mycoplasma pneumonia infection was significantly more prevalent in MS patients than in healthy individuals (p< .05). MS patients were more likely to suffer from common colds (p< .05), but no significant difference was observed regarding other infectious diseases (p> .05). Additionally, the prevalence of chronic infections was higher among MS patients (p< .05).
Conclusion: M.pneumoniae infection, common colds, and chronic infections were significantly more common in MS patients than in healthy controls. However, no significant association was found between other infectious diseases and MS risk. These findings emphasize the possible role of specific pathogens in MS development, warranting further investigation into underlying mechanisms and contributing factors.
Volume 11, Issue 1 (Winter 2025)
Abstract
Background: Dairy products are considered as some staple food rich in nutrients. Among dairy products, ice cream is one of the most attractive and popular products. The popularity of ice cream is due to its great taste and unique texture. Considering the prevalence of traditional ice cream consumption in Iran and the risk of microbial contamination of these products, the microbial quality of industrial and traditional ice creams in Fars province was evaluated and compared.
Materials & Methods: A total of 470 ice cream samples were tested to determine total viable count (TVC), total coliform count (TCC), and the presence of fungi. Biochemical properties and antibiotic sensitivity of isolated bacteria were investigated.
Findings: TVC in all industrial ice cream samples was lower than the limit specified by the national standard of Iran. Coliform levels in 37% (n=100) of traditional and 1.5% (n=3) of industrial ice cream samples were higher than the permissible limit. Furthermore, 74.8 and 40% of traditional samples contained Escherichia coli and fungi and mold, respectively. Antibiogram results showed that the highest antibiotic resistance of the isolates was related to ampicillin and trimethoprim/sulfamethoxazole.
Conclusion: Traditional ice creams are highly contaminated with microbial agents resistant to two or more drugs, which poses great risks for the consumers of these products, especially children. Therefore, it is necessary to implement appropriate hygiene practices to increase the safety of ice creams. Alerting people about the risks of foodborne diseases could significantly help prevent such diseases.
Volume 12, Issue 1 (12-2020)
Abstract
Biosurfactants are produced by microorganisms. Surfactin is one of the main lipopeptide biosurfactants produced by different species of Bacillus subtilis. This study aims to analyze the effect of starch-coated Fe0and Fe3+nanoparticles on the biosurfactant production of Bacillus subtilis. Out of 70 soil samples, 20 Bacillus were isolated and genome sequenced by biochemical methods and 16S rRNA gene. Quantitative and qualitative screening methods were used to isolate and detect biosurfactant production. For the aim of this study, 61 and 63 (Bacillus subtilis subsp. Inaquosorum) were selected. Then, hemolytic activity, surfactant production and reduction of surface tension in Minimal Salt Medium containing Fe0 and Fe3+ nanoparticles were examined after 48h, 72h and 96h of culture. The binding of the nanoparticles to the surfactant was confirmed by SEM. Strain 61 was the best bacterium and Fe3+ was the best nanoparticle and it was cultured. The results were compared with the results of non-nanoparticle bioreactor. Surfactin from strain 61 culture in the Fe3+ nanoparticle bioreactor after 72 hours of growth showed higher production than the same strain culture after 72 hours without Fe3+, if continuing the research, this strain can be commercialized in the future.
Volume 13, Issue 3 (10-2024)
Abstract
In the present study, the fish protein isolate (FPI) of wastes of Siberian sturgeon (Acipenser baerii) has been substituted with fish minced (10, 20, 30, and 40%) in preparing fish nuggets. After preparing fish nuggets (88% Silver carp fillet) and initial cooking, the parameters such as approximate analysis, product yield, weight loss, pick-up, microbial growth, and sensory evaluation were investigated. The results showed that the lowest amount of moisture is related to the IP40 Group and no significant difference exists between other treatments. In comparison, the amount of protein in the control sample was the highest (18.00 ± 0.04) and it was decreased with the increase of FPI substitution (P<0.05). The highest amount of weight loss during final cooking was related to the control and IP10 treatments, and the highest product yield was associated with IP20, IP30, and IP40 treatments (P<0.05). The microbial growth results did not show any significant difference among the treatments (P>0.05). Moreover, the sensory evaluation showed the control group, which was only with fish minced, had better taste, smell, texture, etc. than the treatments containing isolated protein. The results of this research showed that the minced fish of silver carp and the FPI by-product can be used to produce fish nuggets, and although in some physical properties, the nuggets containing higher amounts of isolated protein have shown better results, according to the amount of protein and sensory evaluation, the control and the sample containing %10 FPI had better results.
Volume 13, Issue 55 (9-2015)
Abstract
Biosurfactants are amphiphilic compounds that are produced by bacteria and fungi and they are able to reduce surface tension. These compounds are preferred due to less toxicity and better degradation than chemical surfactants and they have many applications in the petroleum, food and pharmaceutical industries. The purpose of this study was the investigation of production conditions of biosurfactant from Bacillus strains identified in Biotechnology Laboratory, Chemical Engineering Department, Tehran university, that been named HR1, HR2, and HR3. Materials and Methods: After performing the inoculation, the culture medium incubated at different temperatures and times and rotation rates and then obtained biosurfactant extracted and measured by solvent. According to the results, temperature, incubation time and rotation rate are affecting factors on biosurfactant production. The maximum amount of biosurfactant was obtained by HR1 in 33 °C and 150 rpm after 5 days incubation. acillus HR1 is appropriate for biosurfactant production for use in various industries, especially in the food industry.
Volume 14, Issue 1 (March & April 2023 (Articles in English & French) 2023)
Abstract
Scholarly publication has turned into a growing concern affecting the lives of academics across the world. The increasing demand by higher education institutions for publications in high-profile venues has created various policy issues, including the ones about the language of publication, and more specifically, about writing and publishing in English by speakers of other languages. In this study, we investigate policies of publishing in English in Iranian higher education based on qualitative content analysis of 30 national policy documents and 170 university bylaws released by 46 Iranian universities over the past twenty-three years. The emerging policy lines reveal that the research evaluation system and the structure of incentives as well as institutional pressure mechanisms all tend to act in favor of publishing in English in a context where it is the academic language of only a small minority. The implications of such policy directions for higher education in Iran are discussed along with possible messages for other contexts around the world.
Volume 14, Issue 13 (First Special Issue 2015)
Abstract
In this paper, the free vibration and low velocity impact response of a sandwich plate with a Magneto Rheological (MR) flexible core have been studied. The rectangular sandwich plate contains a Magneto Rheological (MR) flexible core and two constrained layers. The MR materials have different properties with respect to different magnetic field intensities. The governing equations of motion have been derived using Hamilton principles. The solution of these equations was obtained using Fourier series and analytical systematic procedure. Using the proposed solution method, the natural frequencies, structural loss factors, impact load and transverse deflection of the plate were calculated. Also, the contact force history was derived using a two degrees of freedom spring mass model analytically. The effects of variations of magnetic field intensity on the natural frequency, loss factors, contact force and deformations of the plate and impactor were investigated. In ordre to calculate the equivalent mass of the plate, the obtained fundamental natural frequency from solution of eigen value problem was used. The obtained equivalent mass of the plate was used in analytical spring mass model. The results show that with systematic variation of magnetic field, the magnitudes of transverse stiffness, structural loss factors and maximum contact force can be changed and controlled, respectively.
Volume 14, Issue 14 (Second Special Issue 2015)
Abstract
In this paper, the behavior of multi-layered ceramic armor and ceramic armor with ductile backing against armor piercing APM2 projectile has been considered numerically. Multi-layered armors in accordance with BR7 ballistic protection class should protect against AP 7.62-mm projectiles with impact velocity of 830m/s. Results show that unlike high strength steel, ceramic resists against initial penetration of brass jacket and lead filler and erodes them at initial stages. This enables higher resistance in ceramic armor with similar mass in comparison with the steel one. It is illustrated that ceramic armor with ductile backing beside above characteristics has the capability of bullet jacket strip and capturing brass jacket while the core penetrates through the armor. This characteristic is not observed in multi-layered ceramic armor without the backing plate. Ceramic armor with backing plate reduces projectile's exit velocity one ninth the residual velocity of multi-layered ceramic armor and one nineteenth the residual velocity of high strength steel armor with similar mass. Another point discussed in this paper is the effective ceramic mass resisting against the projectile. The more mass involved, the more ballistic resistance gained.
Volume 15, Issue 1 (3-2015)
Abstract
In this article, the physical and Geometrical effective parameters on free vibration and Force impact a three-layer sandwich plate in the middle layer with magneto rheological (core) Under cross-shot with low speed is investigated. The first natural frequency and loss factor of comparable modal for the first four vibrative modes for Core thickness, magnetic fields and different sheet’s geometrical parameters, is founded. The MR material shows variations in the rheological properties when subjected to varying magnetic fields. These materials with fast response time (in milliseconds) Through a detailed with variation in Magnetic field can be controlled. The governing equations of motion were obtained using Hamilton̕s principle. The results were obtained by the systematic analytical solution. Using the two degrees of freedom mass-spring model, the contact force function can be obtained analytically. The obtained natural frequency from eigen value problem, was used for calculating of equivalent mass of the plate in spring mass model. The results show that with systematic variation of magnetic field and with increasing the ratio of core thickness to the layer thickness and also with increasing the ratio of length to the whole of sheet thickness, we can in order, the stiffness, structural loss factor coefficient and maximum contact force can be changed and controlled.
Volume 15, Issue 1 (3-2015)
Abstract
In this paper, the behavior of multi-layered Alumina ceramic armor against high velocity projectile has been considered. Due to the conoid failure mechanism of ceramics under impact loadings, high compressive strength and erosive behavior of them against projectiles, specially ogive nosed ones, various incorporation of this material in modern armor applications is possible. Consideration of this behavior by means of different constitutive relations in detail, such as given by Johnson & Holmquist, one can design an armor with higher ballistic performance. In this study, "conoid fracture" behavior of "ceramic - elastomer" armor has been simulated in LS - Dyna with Johnson - Holmquist constitutive relation. As a result, the conoid failure of top layer ceramic causes the impact pressure to decrease in back layer, and consequently the epoxy interface transfers the pressure distribution between ceramic layers, causing growth and propagation of conoid failure thus distributing the pressure in larger area, finally resisting against projectile penetration in the armor. Application of this armor system for light-weight and heavy back layer-free purposes, would be of the highest priority against high velocity projectiles.
Volume 15, Issue 11 (1-2016)
Abstract
Free vibration characteristics of rectangular composite plate with constrained layer damping and magneto-rheological fluid (MR) core are presented.. Hamilton principal is used to obtain the equation of motion of the sandwich plate. Based on the Navier method, a closed-form solution is presented for free vibration analysis of MR sandwich plate under simply supported boundary conditions. The governing equation of motion is derived on the base of classical lamination theory for the faceplates. Only shear strain energy density of the core is considered. Using displacement continuity conditions at the interface of the layers and core, shear strain of the core is expressed in terms of displacement components of the base and constraint layers. The complex shear modulus of the MR material in the pre-yield region was described by complex modulus approach as a function of magnetic field intensity. The validity of the developed formulation is demonstrated by comparing the results in terms of natural frequencies with those in the available literature. The effects of magnetic field intensity, plate aspect ratio, thicknesses of the MR core, base layer and constrained layer for three different stacking sequences of composite faceplates on the fundamental frequency and loss factor of the first mode are discussed. The results indicate significant effect of physical and geometrical parameters on the natural frequency and loss factor associated with the first mode.
Volume 16, Issue 12 (2-2017)
Abstract
One of the common ways to reduce vibration in the structures is to add a thin viscoelastic material layer to the structure. By appropriate using of viscoelastic materials one may increase modal loss factor of the structure and reduce unfavorable structural vibration which is a main cause of fatigue and failure in the structures. In this paper, low velocity impact response of sandwich plate with magnetorheological fluid core is investigated. Hamilton principal is used to obtain the governing equation of motion for sandwich plate. Free vibration problem of the sandwich plate is solved using the Navier solution method. Classical lamination theory is used to analyze the mechanical behavior of the composite laminate in the facesheets. Only shear strain energy of the core is considered and viscoelastic behavior of the MR material was described by complex shear modulus approach as a function of magnetic field intensity. Furthermore, analytical solution for impact force is obtained by a two degree of freedom spring mass model. For three different stacking sequence of face layers, contact for history and variation of maximum impact force and it’s corresponding time by magnetic field intensity is investigated. The results show considerable effect of variation in magnetic field intensity on maximum impact force and it’s corresponding time.
