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Showing 3 results for Magnetic Fields


Volume 13, Issue 1 (3-2022)
Abstract

Investigation of factors affecting endothelial cell proliferation is an essential part of angiogenesis studies. Given the importance of inhibiting angiogenesis in the treatment of cancers, and due to the side effects and high cost of anti-angiogenic drugs such as Avastin, the use of physical agents to aid in treatment and reduce the need for high doses of the drug is noteworthy. Magnetic fields are of interest due to their long-distance and non-invasive effects, and many studies have been conducted on their effects on biological phenomena, including angiogenesis, with inconsistent results. In the present study, the effect of a 2 mT alternating magnetic field with a frequency of 200 Hz and Austin on the proliferation of human umbilical vein endothelial cells (HUVEC) was investigated. Cells were treated for 48 hours under a mixture of 50 μg/ml solution of vascular endothelial growth factor (VEGEF) and Avastin at concentrations (zero (drug control), 50, 100, 200 and 400 μg/ml) as well as field treatment groups for They were exposed to magnetic fields for 3, 6, 12, 24 and 48 hours. Then, cell proliferation was assessed using Alamar Blue colorimetric test. Data were analyzed by three-way analysis of variance. According to the findings, the exposure times of 12, 24 and 48 hours showed a significant reduction in cell proliferation compared to the control group, but this difference was not significant in the 3 and 6 hour treatments. Also, the degree of interaction of these factors with each other on HUVEC proliferation was investigated.
Mohammad Hosseini, Abbas Zandi Baghche Maryam,
Volume 16, Issue 11 (1-2017)
Abstract

In this research, based on nonlocal elasticity theory, static and dynamic analysis of an elastic homogeneous nanotube conveying fluid with clamped - clamped boundary conditions is investigated. The nanotube is under electrostatic actuation and magnetic field with considering the surface effects, mechanical and thermal force. Transverse displacement of the nanotube consists of two parts static and dynamic displacement. In this study, the static displacement is calculated by using the weighted residual method and instability and vibration frequency is analyzed by applying the generalized differential quadrature method. By applying a voltage greater than the critical value (called Pull - in voltage) the nanotube may undergo instability. In this investigation, the effect of various parameters such as velocity of fluid, length scale parameter, magnetic field, electrostatically voltage, effects of surface layer and thermal loading on the static displacements, natural frequency and Pull - in voltage of the nanotubes conveying fluid has been studied. Finally, the validity of the results by comparing them with the results of the numerical methods in previous research is investigated, in which there is very good agreement between the results of the present work and previous studies. The results show that the length scale parameter is significant parameter in the system's Pull - in voltage and its increasing lead to decreasing the Pull - in voltage. Also, it is shown that the dimensionless frequency and the static displacements, respectively, is decreased and increased with increases in the applied voltage.
Saeed Ansari, Mohammad Reza Karafi,
Volume 24, Issue 9 (8-2024)
Abstract

This paper presents an innovative bulk magnetostrictive actuator made of a 2V-Permendur alloy rod, capable of functioning across multiple deformation modes—longitudinal, torsional, and flexural. In longitudinal mode, displacement is produced by the Joule effect, where a magnetic field applied along the rod’s axis, generated by a surrounding coaxial coil, induces deformation along its length. Torsional mode activation follows the Wiedemann effect, wherein an electric current passed directly through the rod produces a circumferential magnetic field that twists the material. Additionally, flexural deformation is achieved by a special designed magnetic core that directs a magnetic field to the rod’s surface, producing bending movements along the rod’s length. The actuator operates using controlled DC magnetic fields. Experimental results demonstrated outstanding performance, with maximum displacements reaching 12 microns in longitudinal mode, 7 microns in flexural mode, and 0.15 degrees in torsional mode. Such multi-functional performance highlights the actuator’s potential in precision positioning systems, with particular suitability for advanced microscopy, optical instrumentation, and other fields requiring sub-micrometer positioning accuracy.
 

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