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A Novel Electromagnetic Actuation System for Magnetic Nanoparticle Guidance in Blood Vessels
Tehrani, Mohammad Dadkhah,Myeong Ok Kim,Jungwon Yoon IEEE 2014 IEEE transactions on magnetics Vol.50 No.7
<P>Targeted drug delivery using magnetic nanoparticles (MNPs) is a new therapeutic method and is being improved continually. However, recent improvements have focused mainly on the introduction and synthesis of special drugs and there are still limitations getting a drug to desired locations in the body, primarily owing to the small size of nanoparticles and the difficulty of controlling their movement in the body. This paper introduces a new electromagnetic actuation system for guiding MNPs in blood vessels. This system uses six electromagnets powered by currents that can generate a high-gradient magnetic field in the desired direction. A differential current coil (DCC) approach is used to calculate the current applied to each coil. Due to properties of the DCC approach, it is possible to use soft iron cores at the centers of the coils to amplify and concentrate the magnetic field in the desired region and generate a stronger magnetic force than the existing coil systems. To evaluate the performance of the actuation system, a model that guided nanoscale magnetic particles inside special channels was studied using commercial software. To improve the efficiency of the electromagnets for MNP guidance, the structural parameters of the cores and coils were chosen based on the simulation results to get the largest magnetic force in the region of interest, which was set as size of the mouse brain. The proposed actuation system is very compact and less expensive than previous systems. Furthermore, the simulation results demonstrated that the actuation system can generate adequate magnetophoretic forces for nanoparticle steering in a Y-shaped vascular model and can be potentially used as a propulsion tool for MNP guidance in blood vessels.</P>
Tehrani, Mohammad,Eipakchi, H.R. Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.1
In this paper the dynamic behavior of a viscoelastic Timoshenko beam subjected to a concentrated moving load are studied analytically and numerically. The viscoelastic properties of the beam obey the linear standard model in shear and incompressible in bulk. The governing equation for Timoshenko beam theory is obtained in viscoelastic form using the correspondence principle. The analytical solution is based on the Fourier series and the numerical solution is performed with finite element method. The effects of the material properties and the load velocity are investigated on the responses by numerical and analytical methods. In addition, the results are compared with the Euler beam results.
A Novel Scheme for Nanoparticle Steering in Blood Vessels Using a Functionalized Magnetic Field
Tehrani, Mohammad Dadkhah,Yoon, Jong-Hwan,Kim, Myeong Ok,Yoon, Jungwon IEEE 2015 IEEE Transactions on Biomedical Engineering Vol.62 No.1
<P>Magnetic drug targeting is a drug delivery approach in which therapeutic magnetizable particles are injected, generally into blood vessels, and magnets are then used to guide and concentrate them in the diseased target organ. Although many analytical, simulation, and experimental studies on capturing schemes for drug targeting have been conducted, there are few studies on delivering the nanoparticles to the target region. Furthermore, the sticking phenomenon of particles to vessels walls near the injection point, and far from the target region, has not been addressed sufficiently. In this paper, the sticking issue and its relationship to nanoparticle steering are investigated in detail using numerical simulations. For wide ranges of blood vessel size, blood velocity, particle size, and applied magnetic field, three coefficient numbers are uniquely generalized: vessel elongation, normal exit time, and force rate. With respect these new parameters, we investigated particle distribution trends for a Y-shaped channel and computed ratios of correctly guided particles and particles remaining in the vessel. We found that the sticking of particles to vessels occurred because of low blood flow velocity near the vessel walls, which is the main reason for low targeting efficiency when using a constant magnetic gradient. To reduce the sticking ratio of nanoparticles, we propose a novel field function scheme that uses a simple time-varying function to separate the particles from the walls and guide them to the target point. The capabilities of the proposed scheme were examined by several simulations of both Y-shaped channels and realistic three-dimensional (3-D) model channels extracted from brain vessels. The results showed a significant decrease in particle adherence to walls during the delivery stage and confirmed the effectiveness of the proposed magnetic field function method for steering nanoparticles for targeted drug delivery.</P>
Mohammad Tehrani,H.R. Eipakchi 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.1
In this paper the dynamic behavior of a viscoelastic Timoshenko beam subjected to a concentrated moving load are studied analytically and numerically. The viscoelastic properties of the beam obey the linear standard model in shear and incompressible in bulk. The governing equation for Timoshenko beam theory is obtained in viscoelastic form using the correspondence principle. The analytical solution is based on the Fourier series and the numerical solution is performed with finite element method. The effects of the material properties and the load velocity are investigated on the responses by numerical and analytical methods. In addition, the results are compared with the Euler beam results.
Nadia Abbaszadeh Tehrani,Farinaz Farhanj,Milad Janalipour 대한공간정보학회 2022 Spatial Information Research Vol.30 No.4
The first case of COVID-19 was detected in Iran on February 19, 2020. From the beginning of the pandemic, some restrictions have been imposed to reduce the spread of the pandemic, which have led to the reduction or temporary closure of some industrial, construction, and transportation sectors. These sectors are typically some sources of pollutants induced to the atmosphere. The purpose of this study was to investigate the impact of the restrictions caused by the pandemic, on the concentration of nitrogen dioxide ( NO2) in the atmosphere of Tehran province. Average daily and monthly NO2 concentrations from the TROPOMI sensor of Sentinel-5P satellite before and after the pandemic (i.e., February 20 to August 19, 2020, and February 20 to August 19, 2019) were used. The results showed that the average NO2 concentration in the mentioned period in 2020 was equal to 168.09 μmol/m2, which compared to 2019 (195.11 μmol/ m2), had a decrease of 13.85%. Therefore, the imposed restrictions to reduce the prevalence of COVID-19 in Tehran province have an impact on the temporary decrease in NO2 concentration. It is recommended that after the end of the pandemic and the reconstruction of economic and industrial activities, measures will be taken to monitor the urban environmental loads and improve the air quality.
GNSS Jamming Detection of UAV Ground Control Station Using Random Matrix Theory
Omid Sharifi-Tehrani,Mohamad F. Sabahi,M.R. Danaee 한국통신학회 2021 ICT Express Vol.7 No.2
Global navigation satellite systems (GNSS) are the main navigation and control systems in unmanned aerial vehicles (UAVs) and their ground control stations. Without the GNSS signals, the UAV and its ground control stations cannot follow the waypoints of the desired path in jamming environments. In this paper, two new methods for detection of GNSS signal jamming attack for UAV ground control station are proposed based on random matrix theory. By using limiting distribution of mean vector and asymptotic behavior of the defined test statistic, a hypothesis test is introduced and evaluated to detect presence of jamming signal. Simulation results show that the proposed methods have significant performance in terms of detection and false alarm probabilities. Compared to existing methods, at low jamming-to-signal ratio (JSR), more than 2.5 dB improvement is achieved.