Showing 18 results for Saidi
Volume 0, Issue 0 (ARTICLES IN PRESS 2024)
Abstract
Fusarium wilt of bananas is a serious disease affecting banana plantations worldwide. In an effort to sustainably manage the disease, biological control is considered a promising alternative to agrochemicals that can cause detrimental effects on humans and the ecosystem. In this study, we investigated the biological control potential of the present collection of beneficial bacteria which includes Lactiplantibacillus plantarum AM2, Streptomyces morookaensis NRRL B-12429, Bacillus velezensis B4158, B. atrophaeus B363B, and B. amyloliquefaciens B942 against the causal agent of Fusarium wilt disease in banana, Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4) through a dual culture assay and a greenhouse experiment. The inhibition range in vitro was between 31.0 to 42.1%, and the highest growth inhibition of Foc TR4 was observed for L. plantarum AM2. Infected banana plantlets that received the treatment with L. plantarum AM2 also showed a significant reduction in disease severity index as low as 24% compared to treatment with other beneficial bacteria. This study showed that L. plantarum AM2 has a good antagonistic effect on Foc TR4 mycelial growth and the most potential to control Fusarium wilt disease in bananas.
Volume 1, Issue 4 (12-2012)
Abstract
Mycosphaerella graminicola, the causal agent of septoria tritici blotch (STB), is a widespread and significant pathogen of wheat. To determine mating types, 89 isolates were collected randomly from wheat fields of Khuzestan, East Azerbaijan, Ardebil, Kermanshah and Golestan provinces of Iran, during 2006-7. DNA was extracted based on standard protocols. Multiplex PCR was conducted using two pairs of mating type-specific primers for MAT1-1 and MAT1-2. Sensitivity to strobilurin fungicide was determined using strobSNPrc7 and strobSNPrc1 primers. The results showed that in 35 isolates, a fragment of 340 bp amplified with MAT1-1 idiomorph specific primers and in 54 isolates a fragment of 660 bp was amplified with MAT1-2 idiomorph specific primers. While the mating type frequencies were highly unequal, the MAT1-1 was predominant. All isolates were sensitive to strobilurin and amplified a fragment of 639 bp. It is concluded that both mating types are present in Iran, although with different frequencies, which may affect genetic variation through sexual cycle. Meanwhile the studied isolates were not resistant to strobilurin fungicides which may be due to growing wheat cultivars resistant to STB rather than using strobilurin fungicides as a dominant control method.
Volume 5, Issue 17 (10-2017)
Abstract
The test is one of the important and repetitive motives in Iranian stories and is presented in them by different methods and for different purposes. These experiments usually are presented in the stories as a condition which should be overcame by the main character or other characters in order for them to achieve their wishes. The test is regarded as a tool for examining abilities of the characters or a circumstance in which their inner aptitudes are realized in the story.
Although these tests s are very different in the surface, but some common signs and characteristics can be observed in all of them which make it possible for the researchers to categorize them. In this article, the authors have totally chosen 237 stories among Iranian stories and intend to offer a categorized pattern for identification of the types of tests in the Iranian stories by studying their contents. (Including the examiner, the examinee and type and purpose of the experiment).
Volume 10, Issue 3 (1-2003)
Abstract
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Volume 12, Issue 4 (Fall 2024)
Abstract
Aims: This research examined climate change’s impact on the Eurasian otter’s habitat (Lutra lutra) in Khuzestan Province based on habitat modeling in R regarding climate scenarios and the MRI-ESM2-0 general circulation model.
Materials & Methods: 72 points were recorded, and ten climatic and environmental variables were used as inputs for the models. The ROC curve, TSS, and Kappa coefficient were used to assess model accuracy using three different methods.
Findings: In the ROC model, AUC 0.7–0.8 indicates a suitable model, AUC 0.8–0.9 indicates a robust model, and AUC > 0.9 indicates a powerful model. In the TSS model,> 0.75 indicates excellent diagnostic power, 0.4–0.75 indicates good, and < 0.4 indicates weak diagnostic power. The Kappa coefficient (0.39–0.98) shows good prediction accuracy. The RF and GBM were the best for determining the habitat of the Eurasian otter in Khuzestan Province. River distance, BIO1, and BIO3 had the most significant role in habitat suitability. A total of 9176.185 km² of Khuzestan Province was identified as a suitable habitat. The prediction of the species’ distribution changes based on SSP126, SSP370, and SSP585 showed that this species’ habitat would decrease until 2070.
Conclusion: Climate change significantly affects the distribution of the Eurasian otter. Similar to other studies on animal and plant species, it leads to habitat reduction and alterations in habitat ranges.
Somaye Yaghoubi Koupaye, Ahmad Reza Pishevar, Mohammad Said Saidi, Yaser Afshar, Said Mokhtarian,
Volume 14, Issue 5 (8-2014)
Abstract
Precise ascertainment of the diffusion coefficient as the index of penetration of one species through another is essential for accurate physical modeling. The most precise and careful method for computation of these properties is Molecular Dynamics (MD). Unfortunately these methods have huge computational cost. The aim of this article is to introduce a suitable mesoscopic method and an efficient algorithm for calculating diffusion coefficient using this method. In this study we use Dissipative Particle Dynamics (DPD) for calculating diffusion coefficient of the water and lipid through the biological bilayer membranes. Eventually we validate our results with MD simulation and also experimental results. Then we can conclude about this method that besides being efficient from point of computational cost, the proposed algorithm is an accurate method for calculating diffusion coefficient. Therefore using this method, we are able to study the equilibrium behavior of bilayer membranes like calculating diffusion coefficient which with Molecular Dynamics simulations, it maybe takes more than hundreds of times.
Mohamad Hossein Banazadeh, Mohammad Said Saidi, Bahar Firoozabadi,
Volume 14, Issue 8 (11-2014)
Abstract
Since Glomerular filtration of blood in the kidney has been regarded by physiologists for many years, they can access only to the qualitative data. Mathematicians can solve this problem by numerical modeling. In this research, an engineering model is presented for the analysis of this capillary network by investigating in the different scientific fields such as, physiology, medicine, computer science and mathematics.First of all, the homogeneous model introduced by Deen, are studied. The rate of the blood filtration is achieved by solving the 2-D equations of momentum and mass transfer. Then the anatomic investigation of the glomerular are performed to present a three-dimensional network of the glomerular capillaries. This proposed model is solved numerically by Use of the 3-D equations of momentum and mass transfer. This analysis makes it possible to study the various parameters are creating by diseases and this is the main advantage of this provided mode. In network model connection between lobules and their shapes just improve flow distribution and mass transfer. Otherwise the glomerular filtration rate in the flow rate of more than 150 nl/min is evaluated more accurately in this model.
Behzad Damichi, Milad Rismanian, Mohammad Said Saidi, Bahar Firoozabadi,
Volume 14, Issue 15 (Third Special Issue 2015)
Abstract
With the increasing development of the pharmaceutical industry and producing drugs with specific performance, its transfer into cells is also very important. Cell membranes are effectively impermeable to hydrophilic compounds unless the permeation is facilitated by dedicated transport systems. As a consequence, there is much interest in finding ways to facilitate the transport of molecules across cell membranes. Cell-penetrating peptides (CPPs) in particular have shown much promise as potential delivery agents. That have been claimed to penetrate cell membranes in an energy- and receptor-independent manner. In the present investigation, the translocation of PENETRATIN into the cell membrane is carried out applying constant velocity steered molecular dynamics via MARTINI coarse grain approach. In order to study the orientation of peptide as it get closer to the membrane, equilibrium simulation is carried out and it is shown that to investigate the penetration process, we need to apply steered molecular dynamics simulation. Energy barrier upon the insertion is calculated and its diffusion in the membrane is considered. It is shown that pore formation phenomenon breaks down the energy barrier and facilitates the translocation process which is in agreement with previous researches. Furthermore, 110 kJ/mol energy barrier is obtained from simulations for this peptide.
Vahid Khandan, Bahar Firoozabadi, Mohammad Said Saidi,
Volume 15, Issue 1 (3-2015)
Abstract
Alzheimer’s disease (AD) is the most common type of dementia in the elderly. The neuropathology and treatment of AD is not precisely determined yet, but according to the pathological studies, AD is associated with presence of toxic soluble oligomers and insoluble senile plaques formed by amyloidosis of Amyloid Beta (Aβ) in neocortical region of brain. The V10HHQKLVFFAE22 is a critical region of Aβ42 which facilitates aggregation process. An attractive therapeutic approach to treat AD is to identify small ligands that are capable of binding to critical residues in order to inhibit or reverse Aβ amyloidosis process as source of neurotoxicity. In this area, therapeutic efforts designed various organic agents and most of them focused on the N-terminal sequence of Aβ. Here, a peptide inhibitor derived from the C-terminal of Aβ (G33LMVG37) is utilized as inhibitor and combined Docking and Molecular dynamics simulation used to find the binding sights in the critical region (V10HHQKLVFFAE22). The simulation identified tree stable binding sites for Aβ42 inhibition by penta peptide. This result indicate that this penta-peptide is capable to inhibit aggregation process and can be consider as an drug for AD preclinical studies.
Mohammadmehdi Naghizadeh, Amirreza Ghahremani, Mohammad Hassan Saidi,
Volume 15, Issue 4 (6-2015)
Abstract
In this study, spray behavior of bio-ethanol as a regenerative fuel that reduces emissions such as NOX and CO is investigated in a combustion chamber and compared to its different blends with gasoline. For this purpose, microscopic and macroscopic spray characteristics and also evaporated fuel mass after the injection are modeled and investigated using Fire 2013. It is concluded by increasing bio-ethanol content in the fuel, evaporated fuel mass, spray cone angle, spray area and sauter mean diameter increases, however spray tip penetration remains roughly constant. Increase of injection pressure, decreases spray cone angle and suater mean diameter and increases evaporated fuel mass, spray area and spray tip penetration. If the energy content and time of injection of bio-ethanol and gasoline be equivalent the results vary significantly compared to previous cases. In this case bio-ethanol has a longer spray tip penetration and spray area, higher fuel mass evaporated and smaller spray cone angle and sauter mean diameter compared to gasoline. The increased spray tip penetration and spray area in this case may lead to piston impingement and bore wetting resulting increased hydrocarbon emissions and decreasing engine efficiency.
Milad Reshadi, Mohammad Hassan Saidi,
Volume 15, Issue 4 (6-2015)
Abstract
Dissemination of an analyte under the laminar flows plays a major role in measuring and assessment of biological fluids such as sample preparation in the context of microfluidic systems. Due to the development of manufacturing technology in the Lab-on-a-chip devices, the production of rectangular microchannels with finite aspect ratios and micron and submicron sizes has been provided by which the effect of electrokinetic phenomena on concentration distribution will be magnified in these systems. Since the recent researches in this field have overlooked such effects, the present work will be conducted analytically to study the effect of electric double layer on cross stream diffusion of the analyte in the combined electroosmotic and pressure driven flows. Three flow scenarios, the favorable, adverse and zero pressure gradients are analyzed. The results demonstrate that the width of the diffusion region near the top and bottom walls of the microchannel becomes broader with the increase in the Debye length. Also, the results of the scaling analysis reveal the decrease in mixing intensity with increasing the Péclet number based on Helmholtz-Smoluchowski velocity and dimensionless Debye–Hückel parameter. As well, the average scaling exponent of this criterion is a descending function with respect to the thickness of the electric double layer.
Hadi Keramati, Mohammad Hassan Saidi, Mohammad Zabetian,
Volume 15, Issue 5 (7-2015)
Abstract
In many industrial processes, in the middle stages of production, the final product or residuals contains aqueous suspensions. The instability of suspensions is one of the main challenges towards the mentioned processes. Present study is the result of an experimental investigation that analyzed the effect of Silica nanoparticles on the stabilization of Zirconia microsuspension. The effect of Zeta potentialof micro and nanoparticles on theperformance of the stabilization method by generation of nanoparticle halos were studied experimentally. The turbidity of microparticle suspension, was measured before and after addition of nanoparticles at different PH values. The results of experiments shows that for all PH values, the addition of nanoparticles increases the stability of the suspension.The achieved stability is due to the formation of nanoparticle halos that has been observed using a scanning electron microscope (SEM). Nanoparticle halos decreases the Wan der Waals attractive force and increases the electrostatic charge of microparticles and consequently increases the stability of the resultant suspension.The strength of the stability varies with PH values due to the difference in the electric charge. The maximum stability occurs at the isoelectric point of Zirconia microparticles. When microparticles have relatively low electric charge, the potential sink around them are deeper and thus more nanoparticles form halos. The minimum stabilization also occurs when the microparticles have relatively high electric charge that increases the repulsive force between micro and nanoparticles.
Alireza Saidi, Amin Safi Jahanshahi,
Volume 15, Issue 12 (2-2016)
Abstract
Mechanical behavior of live cells and tissues is non-linear and their deformations are large. Using a suitable mechanical model that could predicts this behavior, is an important step in the prevention and treatment of various diseases and the production of artificial tissues. In this paper, using the non-linear elasticity theory and non-linear Mooney-Rivlin model, mechanical analysis of human arteries has been studied under internal pressure and axial tension. In the first By using the experimental study was conducted of biaxial test, the elastic constants of the arteries are calculated. For modeling, the arteries are considered as long homogeneous and isotropic cylinders. Radial and circumferential stress distribution on the minimum and maximum blood pressure is calculated. Variation of artery radius due to internal pressure is calculated and compared with the reported experimental data, and a good agreement is seen. The stress distribution curves versus radius are plotted which show that the inner layers of the arteries have much greater role in stress distribution than the outer layers. The elastic constants which are calculated for different ages show that the arteries of older people become stiffer and their flexibility decrease.
K. Maleki Bagherabadi , M. Sani, M.s. Saidi ,
Volume 19, Issue 8 (August 2019)
Abstract
Micro-mixers are vital components of “Lab-on-a-Chip” devices. Their main functionality is the mixing of two streams with desired quality and at minimum mixing time. In this work, numerical modelings of some active and passive micro-mixers with innovative designs are reported. Increasing mixing quality and decreasing mixing time are the design objectives. Our numerical model features solving the set of non-linear and inter-coupled Poisson-Nernst-Planck-Naiver-Stokes equations (PNP-NSE) instead of using simplified models like Poisson-Boltzmann (PB). These equations describe a more realistic model of the physics involved at continuum level by incorporating diffusion, electro-migration, and convection, which are the dominant phenomena in electro-kinetic micro-mixers especially those using AC voltage electrodes. The computations are carried out using Rayan (in-house code). The traditional Poisson-Boltzmann (PB) model relies on simplifying assumptions and is proven to lose its accuracy in complex geometries and near active electrodes. On the other hand, the PB model is much less sophisticated and therefore much less computationally expensive. One of the contributions of this research is to show that in passive micro-mixers making the obstacles smaller but more numerous increases the mixing quality (for the case studied by 13%). The other major contribution of this work is the introduction of the combination of the vertical and horizontal AC electrodes. This new design creates jets normal to the direction of the mainstream which is responsible for enhancing chaotic mixing. This results in a stable mixing quality of 99% at 2.7s.
A. Bahrami, H. Moghadas, M.s. Saidi ,
Volume 20, Issue 8 (August 2020)
Abstract
Research on DNA is particularly important in the diagnosis, control, and treatment of many diseases, including cancer. Today, the use of digital droplet polymerase chain reaction (ddPCR) for different DNA tests has attracted much researchers’ attention. A large number of micron-sized droplets are required to perform ddPCR. In the present study, a ddPCR system was designed, fabricated, and evaluated using a microfluidic chip. The system comprises a microfluidic chip for droplet generation and a thermal cycling device needed for PCR. The droplet generation in the microchip was simulated in 3D. The simulation results were validated. The average error is about 5% in the radius of the droplets. The constructed thermal cycling device controls the chip temperature with a precision of ±1.5°C. The in-chip PCR process was successfully performed by applying 25 heat cycles. The fluorescent property was observed in most droplets that prove the thermal cycling device can provide the conditions for DNA proliferation in the laboratory. The images were processed, and different levels of fluorescent light were identified in the droplets. The coefficient of variation of the selected droplets is 2.5%, which gives a good accuracy compared to the acceptable amount for these types of systems (less than 8%). The results obtained from this fully native device can be used in many fields, including cancer detection, examination of malignant tissue, and evaluation of the success in tissue surgery.
Volume 23, Issue 3 (5-2021)
Abstract
Differential induction of genes in wheat (cv. Chamran) in response to Mycosphaerella graminicola was studied using cDNA-AFLP analysis. The three weeks old wheat seedlings were inoculated by the fungal pathogen, then the samples were collected at six time points (0, 12, 24, 48, 72, 96 hours) after inoculation with pathogen. By comparing the expression patterns of induced (infected) with non-induced (uninfected) plants, 276 differentially expressed fragments were identified and sequenced. Blast search of wheat genes assigned these sequences to different functional categories including defense, metabolism, energy, transcription, transport, signal transduction, stress response, secondary metabolism, and unknown sequences. Eight defense-related genes including lipoxygenase, peroxidase (PR 9), chitinase (PR 2, 4, 8) , PR-1, thaumatin-like protein (PR5), Phenylalanine Ammonia Lyase (PAL), β-1-3 glucanase (PR3), disulfide isomerase, and methionine sulfoxide reductase were induced 12 to 24 hours after inoculation in this cultivar of wheat. Induction of glucosyltransferase, Catalase, and putative xylanase inhibitor genes were observed around 48 h after inoculation with pathogen. Expression patterns of the other three genes, i.e., chalcone synthase, EXECUTER 1 protein, and nonspecific lipid transfer protein showed that these genes were induced later after inoculation (72-96 hours). Our data showed that expression of the PR- proteins were enhanced 24 h after inoculation, suggesting that they may play a role in the defense against M. graminicola. Expression of lipoxygenase, glycosyltransferase, thaumatin like protein, putative xylanase inhibitor, EXECUTER 1 protein and Nonspecific lipid transfer protein are reported for the first time in this interaction.
Volume 24, Issue 2 (8-2018)
Abstract
Immigration to Europe has significantly increased over the past several years and Afghan refugees are the second largest displaced group entering European borders after Syrians. Germany has been a preferred destination for many refugees and in 2015 the country welcomed over one million asylum seekers from around the globe which made it as some called it “Kabul of Europe". Immigration, both voluntary and forced, is driven by social, political and economic factors. Urban life in Europe, especially in a developed country like Germany, is completely different from traditional life in Afghanistan. After spending times in the camp, Afghan women gradually enter the urban life of the destination country which impacts the function of a traditional Afghan family. This article tries to seek the notion of "change" amongst Afghan families while they encounter migratory experiences in urban life in German societies. The main aim of the research is to analyze the process of acculturation of immigrant Afghan women in Germany in terms of educational attainments, language proficiency and entering to the workplace which will empower and enable them to redefine their identity in their new urban setup. This research is based on a qualitative method which consists of 51 in-depth interviews with Afghan (Hazara) migrant girls and women in refugee camps, as well as the city of Hamburg and Bremen in Germany.
Volume 27, Issue 4 (1-2021)
Abstract
An ever-increasing trend of international migration of educated and skilled Iranian women over the past years has been one of the policy challenges and requires a comprehensive pathological study. The current research seeks to investigate the effects of the unbridled expansion of higher education in accelerating the migration of skilled women abroad. This is a qualitative study where the data is based on 24 semi-structured interviews with women PhD holders who are intentionally want to go abroad to pursue their studies or career. A set of factors at two micro levels such as the requirements of the individual’s social environment along with effective factors at the macro level lack like the role of telecommunication especially internet and likewise level of welfare and educational and living standard of industrialized countries, gender inequality in accessing available opportunities, The dominance of quantum in promoting university institutions, the slight growth of higher education and imbalance with the needs and capacity of the labor market reinforce the fantasy of migration and the overflow of talents into a fantasy world called "foreign". A review of policies of the Ministry of Education and Universities and coherent planning in order to direct social demands to the needs of the labor market, focus more on research instead of training of academic departments, cultivate specialized and committed manpower, strengthen cooperation are required in order to creating a fertile and safe scientific environment for young professionals and trying to reduce gender gaps which will slow the migration of educated women.
