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Showing 17 results for Khalaj


Volume 5, Issue 3 (9-2017)
Abstract

Aim: The aim of this study was to determine the effect of socioeconomic factors on the constructs of the modified Theory of Planned Behavior (TPB) in relation to reproductive health in adolescents.
Methods: A cross-sectional study was conducted among 578 female students aged 12-16 years, recruited through a multistage random cluster sampling method, in Tehran, Iran. A self-administered TPB-based constructed questionnaire was designed and used for data gathering. Multivariate regression analyses were conducted to examine the association between family size, number of siblings, birth rank, and family closeness, source of information, and reproductive health behavior.
Findings: The mean age of the participants was 14.1 years. None of the participants obtained a perfect score in relation to reproductive health. In addition, they achieved average scores less than half the rates. Number of siblings, family size, birth rank, mother education and information source were factors associated with TPB the constructs (p<0.001).
Conclusion: The results of this study emphasize that Socioeconomic factors can have an effective role in students' sexual and reproductive health behaviors.

Volume 13, Issue 1 (1-2024)
Abstract

The aim of this study was to evaluate fish meal replacement by a bacterial single cell protein (IPL68) on growth performance, digestive enzymes activity (protease, lipase and α-amylase), gut histology and gut microbiota in rainbow trout fry (initial weight = 2.51 ± 0.55 g) for 6 weeks. Five diets were formulated with different bacterial SCP level (0:D1, 25:D2, 50: D3, 75:D4 and 100: D5 %) to replace fishmeal protein. At the end of the trial, body weight gain, specific growth rate, condition factor and hepatosomatic index showed the higher values than other diets with a significant differences (P<0.05). The food conversion ratio had the lowest and highest values in D3 and D5 diets, respectively, with a significant difference (P<0.05). The survival rate in all experimental diets was 100%. The highest activity of protease, lipase and α-amylase enzymes was observed in the intestines of fish fed with D3 diet, which showed a significant difference compared to D4 and D5 diets (P<0.05). The highest number of total bacteria and lactic acid bacteria was observed in diet D3, which was significantly different from other diets (P<0.05). The highest villus height (µm) and the ratio of villus height to crypt depth was observed in fish fed with D3 diet, which was not significantly different from D1, D2 and D4 diets, but showed a significant difference with D5 diet (P<0.05). Based on the obtained results, D3 diet can be suitable for the growth of rainbow trout fry compared to other diets.


Volume 14, Issue 4 (7-2014)
Abstract

Tractor-trailer wheeled mobile robot (TTWMR) is a robotic system that consists of a tractor module towing a trailer. Trajectory tracking is one of the challenging problems which is focused in the context of wheeled mobile robots (WMRs) that has been discussed in this paper. First, kinematic equations of TTWMR are obtained. Then, reference trajectories for tracking problem are produced. Subsequently, an output feedback kinematic control law and a dynamic Fuzzy Sliding Mode Control (FSMC) are designed for the TTWMR. The proposed controller steer the TTWMR asymptotically follow reference trajectories. Finally, experimental results of the designed controller on an experimental setup and comparison results are presented. Obtained results show the effectiveness of the proposed controller.

Volume 14, Issue 12 (3-2015)
Abstract

In this paper, trajectory tracking control of a wheeled mobile robot is analyzed. Wheeled mobile robot is a nonlinear system. This system including three generalized coordinates (x,y,ϕ), and a nonholonomic constraint. First, system kinematic and dynamic equations are obtained. A non-model-based control algorithm using PD-action filtered errors has been used in order to control the wheeled mobile robot. Non-model-based controllers are always more appropriate than model-based algorithms due to independency from dynamic models, lower computational costs and also robustness to uncertainties. Asymptotic stability of the closed loop system for trajectory tracking control of wheeled mobile robot has been investigated using appropriate Lyapunov function and also Barbalat’s lemma method. Finally, in order to show the effectiveness of the proposed approach simulation and experimental results have been presented. Obtained results show that without requiring a priori knowledge of plant dynamics, and with reduced computational burden, the tracking performance of the presented algorithm is quite satisfactory. Therefore, the proposed control algorithm is well suited to most industrial applications where simple efficient algorithms are more appropriate than complicated theoretical ones with massive computational burden.
Leila Nematollahi, Fereidoun Mahboudi, Mohammad Azizi, Farzaneh Barkhordari, Ahmad Adeli, Vahid Khalaj,
Volume 15, Issue 3 (10-2012)
Abstract

Objective: Bone morphogenetic protein-7 (BMP-7) is a multifunctional growth factor predominantly recognized for its osteoinductive properties. Due to the high cost of this protein, the availability of BMP-7 for treatment is limited. The heterologous production of recombinant hBMP-7 has been performed in a number of expression systems. In this study a novel form of BMP-7 was expressed in eukaryotic and prokaryotic hosts. Methods: For expression in the prokaryotic system, the novel protein was secreted to the periplasmic space of Escherichia coli using a pelB signal sequence followed by single-step purification by Ni2+-charged column chromatography. In the mammalian cell expression system, we transferred a full-length cDNA encoding precursor of the novel protein to CHO cells then selected stable clones by using the appropriate antibiotic concentration. Expressions in both systems were confirmed by Western blot analysis. Results: The novel recombinant protein was produced as a 36-38 kDa dimer in the CHO cell line and a 16 kDa monomer in the Escherichia coli system. Quantitative analysis according to ELISA showed that the expression levels of the mutant protein in the eukaryotic and prokaryotic expression systems were 40 ng/ml and 135 ng/ml of the culture media, respectively. Conclusion: In this study, the expression level in Escherichia coli was at least three times more than observed in the CHO cells. However, further optimization is required to obtain a dimer protein in Escherichia coli. The results show that periplasmic expression may be suitable for the production of complex proteins such as BMPs.

Volume 15, Issue 8 (10-2015)
Abstract

Trajectory tracking is one of the main control problems in the context of Wheeled Mobile Robots (WMRs). Besides, control of underactuated systems possesses a particular complexity and importance; so it has been focused by many researchers in recent years. In this paper, these two important control subjects are discussed regarding a Tractor-Trailer Wheeled Mobile Robot (TTWMR); which includes a differential drive wheeled mobile robot towing a passive spherical wheeled trailer. The use of spherical wheels instead of standard wheels in trailer makes the robot highly underactuated with severe nonlinearities. Spherical wheels are used for the trailer to increase robots’ maneuverability. In fact, standard wheels create nonholonomic constraints by means of pure rolling and nonslip conditions, and reduce robot maneuverability. In this paper, after introducing the robot, kinematics and kinetics models are obtained, and combined as the dynamics model. Then, based on physical intuition a new controller is developed for the robot, named as Lyapaunov-PID control algorithm. Then, singularity avoidance of the proposed algorithm is discussed and the stability of the algorithm is discussed. Simulation results reveal the suitable performance of the proposed algorithm. Finally, experimental implementation results are presented which verify the simulation results.
Hoda Jahandar, Vahid Khalaj, Leila Nematollahi, Fatemeh Zandi, Somayeh Enayati, Behrouz Vaziri,
Volume 16, Issue 4 (2-2014)
Abstract

Objective: The study of physiological changes in recombinant cell lines provides useful information to improve production performance. In this study, we investigate the effects of an anti-CD33 chimeric IgG4 expression on Sp2.0 cell growth. Methods: Variable region genes of light and heavy chains of monoclonal antibody produced by M195 were cloned in pFUSE-CLIg-hk and pFUSE-CHIg-hG4 expression vectors, respectively. Transfection of recombinant plasmids into Sp2.0 cell lines was performed using lipofectamine in two steps. Positive transformant cells were isolated and subjected to PCR, RT-PCR and Western blot analysis to confirm the integration of gene cassettes and the expression of recombinant IgG4. To assess the growth parameters, recombinant and parent Sp2.0 cell lines were seeded at a density of 1×105 cells/ml in duplicate into 12-well plates. For nine days, culture plates were sampled daily and viable cell count and viability determined. Results: The results of PCR, RT-PCR and Western blot analyses confirmed the generation of stable producer cell lines. In recombinant cells, the maximum cell density decreased by 46%. However, it was observed that IgG4 expression had no effect on cell viability of these transfectants. Conclusion: Our results showed that the expression of recombinant IgG4 can change growth parameters in Sp2.0 cell lines that express the pFUSE-CHIg-hG4-pFUSE-CLIg-hk construct.

Volume 16, Issue 11 (1-2017)
Abstract

One of the main topics in the field of robotics is the formation control of the group of robots in trajectory tracking problem. Using organized robots has many advantages compared to using them individually. Among them the efficiency of using resources, the possibility of robots' cooperation, increasing reliability and resistance to defects can be pointed out. Therefore, formation control of multi-body robotic systems and intelligent vehicles attracted considerable attention that is discussed in this paper. First, kinematic and kinetic equations of a differential drive wheeled robot are obtained. Then, reference trajectories for tracking problem of the leader robot are produced. Next, a kinematic control law is designed for trajectory tracking of the leader robot. The proposed controller steer the leader robot asymptotically follow reference trajectories. Subsequently, a dynamic control algorithm for generating system actuator toques is designed based on feedback linearization method. Afterwards, formation control of the robots has been considered and an appropriate algorithm is designed in order to organize the follower robots in the desired configurations, meanwhile tracking control of the wheeled robot. Furthermore the stability of the presented algorithms for kinematic, dynamic and formation control laws is analyzed using Lyapunov method. Finally, obtained results for different reference paths are presented which represents the effectiveness of the proposed controller.

Volume 17, Issue 1 (3-2017)
Abstract

The aim of present article is investigation of evaporation of single- and multi-component fuels droplet and study the effect of unsteadiness term on it. Two approaches are used; a fully transient and quasi-steady approaches. The species, momentum, and energy equations for gas phase and species and energy equations for liquid phase are solve numerically by assuming variable properties with respect to temperature. The results obtained from the fully transient approach show an acceptable compliance with experimental data at atmospheric pressure in a wide range of fuel volatility and ambient temperature for the single- and multi-component fuels. Heptane, decane, and hexadecane are used in order to investigate the effects of fuel volatility on evaporation.The steadiness of processes in the gas phase has been checked by using two measures of unsteadiness related to the mass and heat diffusion of fuel vapor on the droplet surface. The deviations of the results of the quasi-steady approach from the fully transient have been justified by the unsteadiness measures. The results show that fuel and ambient temperature have significant effects on the unsteadiness. For heavier fuels and higher ambient temperature, the diviation of quasi- steady approach from fully transient increases. Also the diviation becomes higher when the differences between volatility of component increase. Therefore, it is concluded that the quasi-steady approach presents reasonable results for lighter fuels in the case of single component and whenever the volatilities of components are very close.
Babak Bakhshinejad, Mohammad Khalaj-Kondori, Saeedeh Ghiasvand Ghiasvand, Majid Sadeghizadeh,
Volume 17, Issue 3 (10-2014)
Abstract

Objective: Recently, phage display libraries have received enormous attention for identification and isolation of pharmaceutical molecules with diagnostic and therapeutic properties. Peptide libraries are known as one of the most important and widely used types of phage display libraries. In the current study, we aimed to screen the Ph.D.TM-7 phage display peptide library through biopanning for the identification of human colon adenocarcinoma-binding peptide ligands. Methods: Three rounds of biopanning were performed on SW480 as the target cell and fibroblast (HF-SF-PI3), AGS, KYSE-30 and Huh-7 as control cells. The displayed peptide-encoding regions in the genome of SW480-binding phages obtained from the final round of panning were amplified by plaque-PCR and subsequently sequenced. Bioinformatic tools were used to determine the sequence of target cell-binding peptides and further characterization of these peptides. Results: Biopanning of the phage library led to the enrichment of several peptides among which the peptide with “HAMRAQP” was the most dominant. Bioinformatic analysis of the isolated peptides indicated that they are not target unrelated peptides (TUP). Conclusion: The peptides, in particular those with the highest frequency, due to having the capability of specific binding to SW480 cells represent the potential for use in targeting of therapeutic genes and drugs to colon cancer cells.

Volume 17, Issue 12 (2-2018)
Abstract

One of the main topics in the field of robotics is the motion control of wheeled mobile robots. Motion control encompasses trajectory tracking and point stabilization problems. In this paper these control problems will be considered for the tractor-trailer wheeled robots and a predictive control algorithm is developed for solving these problems. Therefore first kinematic model of the tractor_trailer robot is developed. Next, reference trajectories is produced for the system. Subsequently, predictive control law is designed for the trajectory tracking and point stabilization problems. Predictive control based on the known values of reference trajectories in the future, produces the control inputs in present time. Consequently the error signal with respect to the reference trajectory in future will be used in order to control the system at the present instant of time. This method is developed for solving the aforementioned control problems and is employed on the tractor_trailer wheeled robot. As can be seen from the results, the proposed control algorithm steer the wheeled robot asymptotically follow reference trajectories. Obtained results from the implementation of the proposed method for solving trajectory tracking and point stabilization problems, demonstrate the effectiveness of the presented algorithm.

Volume 18, Issue 3 (5-2018)
Abstract

In this paper, a new controller is presented based on robust feedback linearization controller in combination with integral-exponential error dynamics and potential functions for tracking control of an underwater robot in an obstacle-rich environment. Underwater robots are considered as nonlinear, underactuated systems with indefinite, uncertain dynamics. In this research, by assuming a boundary for external disturbances and uncertainties a proposed robust control method has been put to use. Along with the robust feedback linearization algorithm which has been developed based on the dynamics of the nonlinear error defined for the underwater robot, and in order to avoid the obstacles, the control laws are combined with the virtual potential functions. The considered virtual potential functions make a repulsive force between the robot and the obstacles which intersect the desired path and then they bring about a safe move of the robot in obstacle-rich environments. Finally, the performance of the proposed new control algorithm is compared with the results of the implementation of classical sliding mode control laws. The results show the effectiveness of potentially directed proposed controller through obstacle-rich paths which operate far better facing obstacles.

Volume 18, Issue 4 (Winter 2015)
Abstract

One of the reasons for the failure of many poverty and inequality reduction programs in developing countries is due to the dominant income-based measurement approach. Therefore, the main cause of poverty is not only a consequence of lack of income, but is also the result of the deprivation of capabilities to get out of poverty. The aim of this study is zoning the incidence and intensity of multidimensional poverty in Iran rural and urban areas and comparing with the results of income per capita indicator classification. The results show that the incidence and intensity of poverty in Iran is respectively 12.3% and 30.6%. Poverty is more prevalent in rural areas compared to urban areas with about 21.4% of the rural households considered poor compared to 5.86% of urban households. The poorest province is Sistan and Baluchestan (S&B) and there are more poorer households in the southeastern provinces. Comparing the classification results of the multidimensional poverty index (MPI) and income per capita indicator displays low overlap. Given the importance of identifying the most vulnerable households in Iran, the MPI seem to offers more valuable and different information to the policy makers, regardless of the problems in measuring the households' income and wealth.

Volume 18, Issue 4 (8-2018)
Abstract

There exist satisfactory results in the analysis of the motion control of the vehicles with the assumption of nonslip (pure rolling) condition of robot wheeles, But unfortunately in practice due to the presence of uncertainties such as sliding of wheels especially in agriculture applications where working conditions are rough the results and the quality of the control performance of the system are affected. The ideal control of wheeled systems is performed with the assumption of the existence of nonholonomic non-slip constraints, while in the real system these constraints are violated due to the presence of slippages. In this paper the problem of trajectory tracking control of wheeled vehicles in the presence of sliding is addressed. To take sliding effects into account, sliding models are introduced into the kinematic model. In other words, these effects are added as unknown parameters to the ideal kinematic model. For taking into account the sliding effects their mathematical models are introduced in system kinematic model. In another word these effects as an unknown parameters are added to the system ideal kinematics. An integrating parameter adaptation technique and backstepping control algorithm has been utilized in order to control the system. The backstepping control law is designed to track the reference trajectories and make the robot asymptotically stable around the reference trajectories. Finally, the obtained results are presented for tracking reference trajectories and comparison results shows the efficiency of using the estimation of slips in control of the system.
M. Azizi, S. Enayati, M. Salmasizadeh, , V. Khalaj,
Volume 21, Issue 1 (Spring 2018)
Abstract

Aims: Expression and purification of recombinant Urate oxidase as well as other pharmaceutical proteins are a costly process. The use of non-chromatographic methods in the purification process can reduce production costs. So, the aim of this study was cloning, expression, and purification of recombinant urate oxidase, using intein sequence and elastin-like protein (ELP).
Materials and Methods: In the present experimental research, the synthetic urate oxidase gene was cloned in downstream of ELP–Intein in an expression plasmid. After cultivating bacteria containing urate oxidase expression plasmid, the soluble fraction of cell lysate was separated from insoluble portion, using centrifugation. The recombinant urate oxidase was precipitated by adding salt and incubation at 37°C. The resulting precipitant was resuspended in cleavage buffer and the urate oxidase was separated from ELP through Intein moiety. Adding salt for the second time and incubation at 37°C resulted in separation of urate oxidase from fusion partner. After expressing and purifying the urate oxidase, purity and biological activity of recombinant urate oxidase were compared to standard drug.
Findings: The recombinant urate oxidase was expressed and purified using ELP and Intein tags as fusions partners. The rescombinant enzyme showed a purity of %90 equal to 1.89 mg.ml-1 based on protein concentration and 1.64 mg.ml-1 based on activity. 
Conclusion: Using Intein sequence and Elastin-like protein, together with the Urate Oxidase enzyme helps to express and purify the enzyme without need for a chromatographic method.

Volume 24, Issue 4 (April 2024)
Abstract

In recent years, advancements in driver assistance technology have significantly minimized the impact of human error on traffic accidents. The development of these systems is of great interest, especially for critical and accident-causing maneuvers such as critical lane change on the highway. One of the important parts of automatic lane change is the motion planning. In this research, taking into account the criteria of collision avoidance and feasibility of the path, an algorithm for the motion planning is proposed. The main innovation of the present research is that the dynamic limits and stability margins of the vehicle have been converted into quantitative criteria and considered in the motion planning. To evaluate the performance of the motion planning algorithm, the complete model of the car is used in the Carsim-Simulink software. Also, to follow the designed path, an integrated longitudinal-lateral control has been designed and implemented. The simulation results show that the proposed method provides a more accurate assessment of the trajectory dynamic feasibility in high-speed critical lane change maneuvers compared to the previous methods. This issue is especially evident for critical maneuvers where the lateral acceleration of the trajectory is more dominant than the longitudinal acceleration.

Volume 24, Issue 10 (October 2024)
Abstract

In many wheeled robot applications, in addition to accurate position control, dimensional and weight limitations are also important. The limitation of weight and dimensions means that it is not possible to use arbitrarily large actuators. On the other hand, accurate and fast tracking usually requires high control gains and, as a result, large control inputs. If the control input exceeds the saturation limit of the operator, in addition to increasing the tracking error, it may lead to robot instability in some cases. Therefore, it will be precious to provide a control method that can simultaneously provide high control accuracy and guarantee the robot's stability, taking into account the saturation limit of the actuators (speed and torque) in a predetermined manner. This issue has been addressed in the present study. The proposed control includes two parts: a kinematic controller and a dynamic controller. The kinematic control design is based on the Lyapunov approach, which can adjust the speed saturation limit of the actuators. For dynamic control, the robot velocity components are considered as control reference values ​​and the robot wheel torque is considered as control inputs. In the dynamic control design, the torque saturation limit of the actuators is included in a predetermined way. To evaluate the performance of the proposed nonlinear control, various analyses were performed on the wheeled robot. The results showed that the proposed control algorithm while guaranteeing stability and following the path with high accuracy, has also fully met the requirements of the actuators’ saturation limits

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