Expression of surface markers and myogenic potential of rat bone marrow- and adipose-derived stem cells: a comparative study

Vahid Bayati,Mahmoud Hashemitabar,Roohollah Gazor,Reza Nejatbakhsh,Dariush Bijannejad 대한해부학회 2013 Anatomy & Cell Biology Vol.46 No.2

In recent years, examination and comparison of the biological characteristics of bone marrow- and adipose-derived mesenchymal stem cells (MSCs) from various perspectives have come into the focus of stem cell research, as these cells should be well characterized in order to utilize them in future cellular therapies. Therefore, in the present study, surface protein markers and the skeletal myogenic differentiation potential of rat bone marrow- and adipose-derived MSCs were examined. The expression of CD44, CD45, CD73, and CD90 on bone marrow- and adipose-derived MSCs was characterized using flow cytometry. Subsequently, the stem cells were differentiated into myogenic lineages, and the expression of the skeletal myogenic markers MyoD1, Myog, and Myh2 was studied in cells using real time polymerase chain reaction and immunofluorescence. Our results reveal that the pattern of CD marker expression differs between these 2 types of MSCs to some extent, whereas no significant difference was observed with respect to their myogenic differentiation potential. Therefore, we concluded that despite the differences observed in the biological features of these 2 types of MSCs, their myogenic potential appears to be similar, and that adipose-derived stem cells may be useful in skeletal muscle tissue engineering, due to their easy isolation and capacity for rapid expansion in a short time span.

Comprehensive Review of Factors Influencing the Use of Telepractice in Stuttering Treatment

Baran Bayati,Haleh Ayatollahi 대한의료정보학회 2021 Healthcare Informatics Research Vol.27 No.1

Objectives: Stuttering is a speech disorder characterized by the repetition of sounds, syllables, or words; prolongation ofsounds; and interruptions in speech. Telepractice allows speech services to be delivered to patients regardless of their location. This review investigated factors influencing the use of telepractice in stuttering treatment. Methods: Articles related tothe application of telepractice in stuttering were searched using the Scopus, Web of Science, PubMed, Cochrane, and Pro-Quest databases without consideration of any time limit. Initially, 79 articles were found and after application of the inclusionand exclusion criteria, 15 articles were selected for the review study. Data were analyzed by using the content analysis methodand synthesized narratively. Results: Factors influencing the use of telepractice in stuttering treatment were categorized intoindividual, technical, clinical, and economic factors. Providing access to healthcare services, maintaining personal privacy,and allowing flexibility in arranging appointments were among individual factors. In terms of the technical factors, technicalproblems and Internet speed were addressed. Clinical factors were divided into positive and negative outcomes, andeconomic factors were mainly related to time and cost savings. Conclusions: Although patients may benefit from using telepractice,the widespread adoption of this technology can be hindered by some technical and non-technical factors. Becausetelepractice can be employed as a complementary method to treat stuttering, more attention should be paid to the requiredinfrastructure and factors that may negatively impact the use of this technology.

Optimized State Controller on DC-DC Converter

M. Bayati Poodeh,S. Eshtehardiha,M. Namnabat 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

Due to their switching property included in their structure, DC-DC converters have a non-linear behavior and their controlling design is accompanied with complexities. But by employing the average method it is possible to approximate the system by linear system and exploiting linear control methods. In this paper the central method of Linear Quadratic Regulator (LQR) is employed for controlling Buck converter and improving its dynamic functioning, but determining the LQR controlling matrices is very difficult. So, genetic algorithm is employed to eliminate this obstacle. The simulation of DC-DC converter with LQR based on genetic algorithm is shown the improvement in voltage control response and the converter output current.

An Adaptive Pole Placement Controller on STATCOM with Genetic Algorithm to Improvement Power System Transient Stability

M. Bayati Poudeh,S. Eshtehardiha,M. Moradiyan 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

STATic synchronous COMpensator (STATCOM) is a device capable of solving the power quality problems at power systems. These problems happen in milliseconds and because of the time limitation; it requires the STATCOM to have continuous reactive power control with fast response. Therefore optimal exploitation of STATCOM by classical controllers has been a controversial issue in recent years. The most common controlling devices in the market are Pole Placement (PP). In this article, the STATCOM is controlled by Pole Placement controller. A new control method that is Model Reference Adaptive Control method (MRAC) based on the combination of Pole Placement control and the Genetic Algorithm (GA) is introduced. Genetic algorithm is employed to find the best values for location of poles controllers" parameters in a very short time. The simulation results show an improvement in current control response.

Ant lion optimizer for optimization of finite perforated metallic plate

Mohammad H. Bayati Chaleshtari,Mohammad Jafari 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.69 No.6

Minimizing the stress concentration around hypotrochoid hole in finite metallic plates under in-plane loading is an important consideration in engineering design. In the analysis of finite metallic plate, the effective factors on stress distribution around holes include curvature radius of the corner of the hole, hole orientation, plate’s aspect ratio, and hole size. This paper aims to investigate the impact of these factors on stress analysis of finite metallic plate with central hypotrochoid hole. To obtain the lowest value of stress around a hypotrochoid hole, a swarm intelligence optimization method named ant lion optimizer is used. In this study, with the hypothesis of plane stress circumstances, analytical solution of Muskhelishvili’s complex variable method and conformal mapping is employed. The plate is taken into account to be finite, isotropic and linearly elastic. By applying suitable boundary conditions and least square boundary collocation technique, undefined coefficients of stress function are found. The results revealed that by choosing the above-mentioned factor correctly, the lowest value of stress would be obtained around the hole allowing to an increment in load-bearing capacity of the structure.

Dynamic analysis by impact load in viscoelastic sandwich plates with FRP layer utilizing numerical method

Mohammad Reza Bayati,Hamid Mazaheri,Mahmood Rabani Bidgoli 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.43 No.2

The main objective of this work is presenting a mathematical model for the concrete slab with fiber reinforced polymer (FRP) layer under the impact load. Impacts are assumed to occur normally over the top slab and the interaction between the impactor and the structure is simulated using a new equivalent three-degree-of-freedom (TDOF) spring–mass–damper (SMD) model. The structure is assumed viscoelastic based on Kelvin-Voigt model. Based on the sinusoidal shear deformation theory (SSDT), energy method and Hamilton’s principle, the motion equations are derived. Applying DQM, the dynamic deflection and contact force of the structure is calculated numerically so that the effects of mass, velocity and height of impactor, boundary conditions, FRP layer, structural damping and geometrical parameters of structure are shown on the dynamic deflection and contact force of system. Results show that considering structural damping leads to lower dynamic deflection and contact force. In addition, increasing the impact velocity of impactor yields to increases in the maximum contact force and deflection while the contact duration is decreased. The result shows that the contact force and the central deflection of the structure decreases and the contact time decreases with assuming FRP layer.

Effect of stacking sequence on thermal stresses in laminated plates with a quasi-square cutout using the complex variable method

Mohammad H. Bayati Chaleshtari,Hadi Khoramishad 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.77 No.2

In this research, the influence of the laminate stacking sequence on thermal stress distribution in symmetric composite plates with a quasi-square cutout subjected to uniform heat flux is examined analytically using the complex variable technique. The analytical solution is obtained based on the thermo-elastic theory and the Lekhnitskii’s method. Furthermore, by employing a suitable mapping function, the solution of symmetric laminates containing a circular cutout is extended to the quasi-square cutout. The effect of important parameters including the stacking sequence of laminates, the angular position, the bluntness, the aspect ratio of cutout, the flux angle and the composite material are examined on the thermal stress distribution. It is found out that the circular shape for cutout may not necessarily be the optimum geometry for all stacking sequences. The finite element analysis results are used to validate the analytical solution.

Shear Strength of Circular and Rectangular Reinforced Concrete Columns

Ahmed Faleh Al-Bayati 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.5

This paper presents two predictive models for the shear strength (SS) calculations of circular and rectangular reinforced concrete (RC) columns subjected to seismic load. Gene expression programming (GEP) is applied using the experimental results from the literature. The GEP models consider the influence of aspect ratio, concrete strength, axial stress, and ratios of transverse and longitudinal reinforcements. Comparisons with existing design equations evidenced the reliability of the proposed models. The parametric study and the sensitivity analysis were also performed to investigate the effect of input variables and to evaluate their contributions to the SS of RC columns.

Optimized design for perforated plates with quasi-square hole by grey wolf optimizer

Chaleshtari, Mohammad H. Bayati,Jafari, Mohammad Techno-Press 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.3

One major concern that has occupied the mind of the designers is a structural failure as result of stress concentration in the geometrical discontinuities. Understanding the effective parameters contribute to stress concentration and proper selection of these parameters enables the designer get to a reliable design. In the analysis of perforated isotropic and orthotropic plates, the effective parameters on stress distribution around holes include load angle, curvature radius of the corner of the hole, hole orientation and fiber angle for orthotropic materials. This present paper tries to examine the possible effects of these parameters on stress analysis of infinite perforated plates with central quasi-square hole applying grey wolf optimizer (GWO) inspired by the particular leadership hierarchy and hunting behavior of grey wolves in nature, and also the present study tries to introduce general optimum parameters in order to achieve the minimum amount of stress concentration around this type of hole on isotropic and orthotropic plates. The advantages of grey wolf optimizer are stout, flexible, simple, and easy to be enforced. The used analytical solution is the expansion of Lekhnitskii's solution method. Lekhnitskii applied this method for the stress analysis of anisotropic plates containing circular and elliptical holes. Finite element numerical solution is employed to examine the results of present analytical solution. Results represent that by selecting the aforementioned parameters properly, fewer amounts of stress could be achieved around the hole leading to an increase in load-bearing capacity of the structure.

Damping the Oscillation in an HVDC/HVAC System with a Novel PSS Controller

M. Moradiyan,M. Bayati Poudeh,S. Eshtehardiha 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

In this paper to damp and control the oscillations in the model system which includes two ties (AC and DC), after any change, a new controller was employed. This controller as a damper can decrease the rotor angle deviations in a short time. This hybrid power system stabilizer use the rotor speed oscillations, capacitor voltage deviations and rotor angle changes as sampling parameters and control the exciter voltage and HVDC’ rectifier control signal. This process is applied with genetic algorithm helps and genetic algorithm is employed to find the best values for gains of the controller in a very short time. The simulation results show the improvement in the dynamic performance of the test AC/DC system.