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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,Milad Janalipour 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.4
The consequences of unsustainable human activities on the environment are often delayed, when it is too late to compensate. New approaches are based on the use of “spatial statistics” of leading indicators to measure the “critical slowing down” in a degraded ecosystem, when it is reaching to a tipping point. This research predicts the tipping points in the ecosystem of Lake Urmia Basin (LUB) based on spatial statistics. By Remote Sensing (RS) indicators, their effectiveness in assessing the state of the ecosystem was evaluated in a 16-years period (2002-2017). Seven spectral indicators (NDVI, NDWIv,NDWIw,NDSI,SRDI, NMDI and MVWR) were extracted from ten MODIS images. Ability of the indicators to identify critical point in time-series was investigated by five spatial statistic methods (Moran’s-I, Getis-Ord-Gi, Geary’s-C, variance, and skewness). The results showed that Moran’s-I is more successful in predicting the ecosystem tipping point(s) in comparison with other methods. In addition, the ability to predict ecosystem trends by the autocorrelation of MVWR is higher than other indicators. According to results, the tipping points of LUB occurred in the years of 2008 to 2010 and 2015. For further studies, it is recommended to use radar indicators for identifying tipping points of the similar vulnerable ecosystems.
Arash Minai-Tehrani,Young-Chan Park,Soon-Kyung Hwang,Jung-Taek Kwon,장승희,Sung-Jin Park,유경남,김지은,Ji-Young Shin,Ji-Hye Kim,Bitna Kang,Seong-Ho Hong,조명행 대한수의학회 2011 Journal of Veterinary Science Vol.12 No.4
Conventional lung cancer therapies are associated with poor survival rates; therefore, new approaches such as gene therapy are required for treating cancer. Gene therapies for treating lung cancer patients can involve several approaches. Among these, aerosol gene delivery is a potentially more effective approach. In this study, Akt1 kinase-deficient (KD) and wild-type (WT) Akt1 were delivered to the lungs of CMV-LucR-cMyc-IRES-LucF dual reporter mice through a nose only inhalation system using glucosylated polyethylenimine and naphthalene was administrated to the mice via intraperitoneal injection. Aerosol delivery of Akt1 WT and naphthalene treatment increased protein levels of downstream substrates of Akt signaling pathway while aerosol delivery of Akt1 KD did not. Our results showed that naphthalene affected extracellular signal-regulated kinase (ERK) protein levels, ERK-related signaling, and induced Clara cell injury. However, Clara cell injury induced by naphthalene was considerably attenuated in mice exposed to Akt1 KD. Furthermore, a dual luciferase activity assay showed that aerosol delivery of Akt1 WT and naphthalene treatment enhanced cap-dependent protein translation, while reduced cap-dependent protein translation was observed after delivering Akt1 KD. These studies demonstrated that our aerosol delivery is compatible for in vivo gene delivery.