Anti-Toxoplasma Effects of Methanol Extracts of Feijoa sellowiana, Quercus castaneifolia, and Allium paradoxum

Mohammad Ali Ebrahimzadeh,Mohammad Mohammad Taheri,Ehsan Ahmadpour,Mahbobeh Montazeri,Shahabeddin Sarvi,Mohammad Akbari,Ahmad Daryani 대한약침학회 2017 Journal of pharmacopuncture Vol.20 No.3

Objectives: The currently available agents for use against toxoplasmosis have serious limitations. Thus, the aim of the present study was to investigate the anti-Toxoplasma gondii (T. gondii) activities of methanol extracts of Feijoa sellowiana (F. sellowiana) (leaves and fruits), Quercus castaneifolia (Q. castaneifolia) (fruits), and Allium paradoxum (A. paradoxum) (leaves) in vitro and in vivo. Methods: Vero cells were treated with different concentrations (from 0 to 400 μg/mL) of the above extracts or with pyrimethamine at a dose of 50 mg/mL (positive control). Then, the viabilities of the T. gondii-infected cells were measured by using colorimetric MTT (3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyltetrazolium bromide) assays. In addition, the survival rates of mice acutely infected with 2 × 104 RH strain tachyzoites of T. gondii were examined in vivo after intraperitoneal injection of the extracts at doses of 100 and 200 mg/kg/day for 5 days. Results: In the in vitro anti- T. gondii assay, the IC50 values were 12.77, 180.2, 74.73, 213.2 and 163.8 μg/mL, and the selectivity indices were 6.05, 1.31, 0.35, 0.69 and 1.30 for the F. sellowiana (leaves and fruits), Q. castaneifolia, and A. paradoxum extracts and pyrimethamine, respectively. Moreover, the mice treated with F. sellowiana (leaves and fruits) achieved better results in terms of survival than the others (P < 0.05). Conclusion: The results of the current study indicate that methanol extract of F. sellowiana has significant anti-Toxoplasma activity. Further study should be conducted to investigate the potential bioactivity of this extract through bioactivity-guided fractionation.

Anti-Toxoplasma Effects of Methanol Extracts of Feijoa sellowiana, Quercus castaneifolia, and Allium paradoxum

Ebrahimzadeh, Mohammad Ali,Taheri, Mohammad Mohammad,Ahmadpour, Ehsan,Montazeri, Mahbobeh,Sarvi, Shahabeddin,Akbari, Mohammad,Daryani, Ahmad KOREAN PHARMACOPUNCTURE INSTITUTE 2017 Journal of pharmacopuncture Vol.20 No.3

Objectives: The currently available agents for use against toxoplasmosis have serious limitations. Thus, the aim of the present study was to investigate the anti-Toxoplasma gondii (T. gondii) activities of methanol extracts of Feijoa sellowiana (F. sellowiana) (leaves and fruits), Quercus castaneifolia (Q. castaneifolia) (fruits), and Allium paradoxum (A. paradoxum) (leaves) in vitro and in vivo. Methods: Vero cells were treated with different concentrations (from 0 to $400{\mu}g/mL$) of the above extracts or with pyrimethamine at a dose of 50 mg/mL (positive control). Then, the viabilities of the T. gondii-infected cells were measured by using colorimetric MTT (3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyltetrazolium bromide) assays. In addition, the survival rates of mice acutely infected with $2{\times}10^4$ RH strain tachyzoites of T. gondii were examined in vivo after intraperitoneal injection of the extracts at doses of 100 and 200 mg/kg/day for 5 days. Results: In the in vitro anti- T. gondii assay, the $IC_{50}$ values were 12.77, 180.2, 74.73, 213.2 and $163.8{\mu}g/mL$, and the selectivity indices were 6.05, 1.31, 0.35, 0.69 and 1.30 for the F. sellowiana (leaves and fruits), Q. castaneifolia, and A. paradoxum extracts and pyrimethamine, respectively. Moreover, the mice treated with F. sellowiana (leaves and fruits) achieved better results in terms of survival than the others (P < 0.05). Conclusion: The results of the current study indicate that methanol extract of F. sellowiana has significant anti-Toxoplasma activity. Further study should be conducted to investigate the potential bioactivity of this extract through bioactivity-guided fractionation.

MRAS Based Speed Estimator for Sensorless Vector Control of a Linear Induction Motor with Improved Adaptation Mechanisms

Mohammad Hosein Holakooie,Asghar Taheri,Mohammad Bagher Bannae Sharifi 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5

This paper deals with model reference adaptive system (MRAS) speed estimators based on a secondary flux for linear induction motors (LIMs). The operation of these estimators significantly depends on an adaptation mechanism. Fixed-gain PI controller is the most common adaptation mechanism that may fail to estimate the speed correctly in different conditions, such as variation in machine parameters and noisy environment. Two adaptation mechanisms are proposed to improve LIM drive system performance, particularly at very low speed. The first adaptation mechanism is based on fuzzy theory, and the second is obtained from an LIM mechanical model. Compared with a conventional PI controller, the proposed adaptation mechanisms have low sensitivity to both variations of machine parameters and noise. The optimum parameters of adaptation mechanisms are tuned using an offline method through chaotic optimization algorithm (COA) because no design criterion is given to provide these values. The efficiency of MRAS speed estimator is validated by both numerical simulation and real-time hardware-in-the-loop (HIL) implementations. Results indicate that the proposed adaptation mechanisms improve performance of MRAS speed estimator.

Multi-project Time-cost Optimization in Critical Chain with Resource Constraints

Mohammad Javad Taheri Amiri,FarshidReza Haghighi,Ehsan Eshtehardian,Ozeair Abessi 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

The simultaneous reduction of the project cost and time has paramount importance in today's competitive world; however, it is necessary to balance the project time and cost because of the reduction asymmetry of the two factors in a project. How to balance the cost and time parameters in managing construction projects is also critical and there have always been some attempts made to provide different approaches to control it. Given the immense importance of considering resource constraints for project scheduling problems, and the proximity of the study conditions to the real world, resource constraints were also included. In a project, project managers need to be aware of resource constraints. As resource constraint scheduling problem is considered NP-hard, the metaheuristic models were developed in this paper in order to obtain results contributing to project managers’ decision-making. For this purpose, a non-dominated sorting genetic algorithm method was developed to optimize a time-cost trade-off problem. Furthermore, to solve a multi-project scheduling problem, the critical chain method was used. In order to evaluate the performance of the model, the developed model was first studied in a small scale and then simultaneous projects with 7, 8 and 10 tasks were planned. Because resource availability is essential in such problems, after solving the proposed model, a sensitivity analysis was performed for daily resources and the results were discussed. Results shows the ability of the proposed model and methodology to optimize the time-cost tradeoff considering resource constraints in sample problems. Solutions obtained showed that in some cases of scheduling without this algorithm, resource consumption exceeded above resource availability. After solving the model by proposed algorithm, resource allocation is implemented considering resource constraint. This model determined these resources as crucial and helped managers to control them.

Rheological properties of Mg based feedstocks with micro or nano Al2O3 powder for injection molding

Sareh Mohammad Taheri 한양대학교 세라믹연구소 2014 Journal of Ceramic Processing Research Vol.15 No.4

In powder injection molding process, the rheological properties of feedstocks significantly influences the steady flow and the uniform filling into the mold. In this study, we investigated the effect of micro and nano size particles of Al2O3 on the rheological properties of Mg-Al2O3 feedstocks. A binder system containing Paraffin wax, Bees wax, and Stearic acid was synthesized. This binder was mixed with pure Mg and Al2O3 powders in various proportions. The Al2O3 powders contained both nano- and micro-Al2O3 differing in concentration from one sample to another. Flow characteristics of the samples were then investigated under different circumstances of shear rate and temperature by means of a rotary rheometer. Viscosity of the feedstocks was found to be decreased with micro size Al2O3 content whereas increased via nano size Al2O3.

MRAS Based Speed Estimator for Sensorless Vector Control of a Linear Induction Motor with Improved Adaptation Mechanisms

Holakooie, Mohammad Hosein,Taheri, Asghar,Sharifian, Mohammad Bagher Bannae The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.5

This paper deals with model reference adaptive system (MRAS) speed estimators based on a secondary flux for linear induction motors (LIMs). The operation of these estimators significantly depends on an adaptation mechanism. Fixed-gain PI controller is the most common adaptation mechanism that may fail to estimate the speed correctly in different conditions, such as variation in machine parameters and noisy environment. Two adaptation mechanisms are proposed to improve LIM drive system performance, particularly at very low speed. The first adaptation mechanism is based on fuzzy theory, and the second is obtained from an LIM mechanical model. Compared with a conventional PI controller, the proposed adaptation mechanisms have low sensitivity to both variations of machine parameters and noise. The optimum parameters of adaptation mechanisms are tuned using an offline method through chaotic optimization algorithm (COA) because no design criterion is given to provide these values. The efficiency of MRAS speed estimator is validated by both numerical simulation and real-time hardware-in-the-loop (HIL) implementations. Results indicate that the proposed adaptation mechanisms improve performance of MRAS speed estimator.

Fuzzy Greedy RRT Path Planning Algorithm in a Complex Configuration Space

Ehsan Taheri,Mohammad Hossein Ferdowsi,Mohammad Danesh 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6

A randomized sampling-based path planning algorithm for holonomic mobile robots in complex configuration spaces is proposed in this article. A complex configuration space for path planning algorithms may cause different environmental constraints including the convex/concave obstacles, narrow passages, maze-like spaces andcluttered obstacles. The number of vertices and edges of a search tree for path planning in these configuration spaces would increase through the conventional randomized sampling-based algorithm leading to exacerbation of computational complexity and required runtime. The proposed path planning algorithm is named fuzzy greedy rapidly-exploring random tree (FG-RRT). The FG-RRT is equipped with a fuzzy inference system (FIS) consisting of two inputs, one output and nine rules. The first input is a Euclidean function applied in evaluating the quantityof selected parent vertex. The second input is a metaheuristic function applied in evaluating the quality of selected parent vertex. The output indicates the competency of the selected parent vertex for generating a random offspringvertex. This algorithm controls the tree edges growth direction and density in different places of the configuration space concurrently. The proposed method is implemented on a Single Board Computer (SBC) through the xPC Target to evaluate this algorithm. For this purpose four test-cases are designed with different complexity. The results of the Processor-in-the-Loop (PIL) tests indicate that FG-RRT algorithm reduces the required runtime and computational complexity in comparison with the conventional and greedy RRT through fewer number of vertices in planning an initial path in significant manner.

Analysis, Design and Implementation of a New Chokeless Interleaved ZVS Forward-Flyback Converter

Taheri, Meghdad,Milimonfared, Jafar,Namadmalan, Alireza,Bayat, Hasan,Bakhshizadeh, Mohammad Kazem The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.4

This paper presents an interleaved active-clamping zero-voltage-switching (ZVS) forward-flyback converter without an output choke. The presented topology has two active-clamping circuits with two separated transformers. Because of the interleaved operation of the converter, the output current ripple will be reduced. The proposed converter can approximately share the total load current between the two secondaries. Therefore, the transformer copper loss and the rectifier diodes conduction loss can be decreased. The output capacitor is made of two series capacitors which reduces the peak reverse voltage of the rectifier diodes. The circuit has no output inductor and few semiconductor elements, such that the adopted circuit has a simpler structure, a lower cost and is suitable for high power density applications. A detailed analysis and the design of this new converter are described. A prototype converter has been implemented and experimental results have been recorded with an ac input voltage of 85-135Vrms, an output voltage of 12V and an output current of 16A.

Fabrication and Dielectric Properties of Pb(Zr0.52Ti0.48)O3 Nanofibers-Cement Composites

Mohammad Khajelakzay,Ehsan Taheri-Nassaj 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.1

In this study, the Pb(Zr0.52Ti0.48)O3 nanofibers-cement composites were fabricated and their dielectric properties were measured. First, lead zirconate titanate (Pb(Zr0.52Ti0.48)O3) nanofibers were synthesized using electrospinning method. Then, the Pb(Zr0.52Ti0.48)O3 nanofibers-cement composites were obtained by pressing the mixture of white cement and the Pb(Zr0.52Ti0.48)O3 nanofibers under a high pressure followed by steam curing. For the composite with 90 vol. %Pb(Zr0.52Ti0.48)O3 nonafibers, the values of εr and tanδ in 1 kHz frequency were obtained to be 777 and 0.067, respectively.

Synthesis and Characterization of Chemiluminescent Conducting Polyluminol via Biocatalysis

Mohammad Reza Nabid,Soheil Salman Taheri,Roya Sedghi,Seyed Jamal Tabatabaei Rezaei 한국고분자학회 2011 Macromolecular Research Vol.19 No.3

The enzyme catalyzed polymerization of luminol (5-amino-2, 3-dihydroxy-1, 4-phthalazinedione) in the presence of polystyrenesulphonate (SPS) is introduced. Polymerization was achieved using horseradish peroxidase (HRP) as a biocatalyst in a phosphate buffer at pH 8. A green, water-soluble conducting PLUM/SPS complex was obtained. The physico-chemical properties of the product, including possible photoluminescence of the PLUM/SPS complex, were studied. The PLUM/SPS complex was shown to be a chemiluminescent (CL) material that is highly sensitive towards Fe^3+ ions. The quantum yield of the PLUM chemiluminescence was determined to be moderate (0.09 ± 0.01) compared to other chemiluminescent compounds. UV-visible, FTIR, ^1H NMR, GPC and conductivity measurements confirmed that the electroactive form of polyluminol (PLUM) was formed and complexed to the SPS.