Showing 43 results for Magnetic Field
Volume 0, Issue 0 (1-2024)
Abstract
This study aimed to increase the vase life of cut rose flowers by improving the regulation of Programmed Cell Death (PCD). Experiments were carried out on cut rose (Rosa hybrida cv. Dolce vita+) flowers under either physical treatment of Static Magnetic Field (SMF; 15 and 25 mT) for 3 hours, or chemical treatments of silver nano particle (Nano-Ag; 5 and 10 ppm), 6-Benzyladenine (BA; 25 and 50 mg L-1), 1% sucrose, and combinations of 5 and 10 ppm nano-Ag with 3 and 6% sucrose. Results showed that a 15 mT-SMF significantly increased vase life up to 25 days, compared to the controls and to all chemical treatments. Among the chemicals, 5 ppm Nano-Ag and 1% (w/v) sucrose increased vase life to 23 and 18 days, respectively. The smallest decline in fresh weight was observed in the 15 mT-SMF physical treatment. Markedly, the 15 mT-SMF treatment led to the least reduction in Chlorophyll (Chl) content. On the 17th day of the applied different treatments, both Water Uptake (WU) and Relative Fresh Weight (RFW) showed an inverse significant relationship with PCD in cut rose flowers, verifying there markable delayed PCD which is favored the market. As a whole, the most effective induced treatments (15 mT-SMF, 5 ppm Nano-Ag, and 1% Sucrose) are suggested to be promising for enhancing postharvest quality and prolonged vase life of cut rose flowers.
Volume 8, Issue 1 (4-2017)
Abstract
In recent years a lot of researches have been carried out about sensitivity of the living organisms to magnetic fields and nanoparticles. Therefore, to evaluate the effect of the magnetic field and silver nanoparticles on photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), proline, glycine betaine, soluble sugars and proteins, nitrate and nitrate reductase activity and protein electrophoresis pattern on Calendula officinalis L., in 2015 experiments were performed in the Department of Biology, University of Urmia. Seedlings were grown for 30 days in four treatments including: control, magnetic field with B = 3 mT for an hour per day, silver nanoparticles (50 ppm), and magnetic field (B = 3mT) plus silver nanoparticles (50 ppm). The results showed that plants treated with magnetic field, silver nanoparticles and magnetic field + silver nanoparticles photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids) content, compatible solutions content such as proteins and soluble sugar, proline andglycine betaine and nitrate content and nitrate reductase activity were significantly (P<0.05) increased compared to control group. Electrophoretic pattern of proteins investigated the maximum bands visible on gel electrophoresis were for treated groups with silver nanoparticles + magnetic field.
Volume 9, Issue 3 (9-2018)
Abstract
Aims: Nitric oxide (NO) plays an important role in maintaining cellular stem status, and the range of electromagnetic fields (EMF) is very deep in contrast to the electric field. The aim of this study was to investigate the effect of electromagnetic field and nitric oxide on the neural differentiation proteins marker and viability of the rat bone marrow mesenchymal stem cells.
Materials and Methods: The present experimental research was conducted on bone marrow mesenchymal stem cells of Vistar rats. For treatments of the cells, high (1mM) and low (10micromolar Deta-NO) concentrations were used as a nitric oxide donor molecule and 50Hz low-frequency electromagnetic field and they were compare with the control group. The cell viability was recorded by MTT assay test, the neural differentiation pathway gene expression was investigated by RT-PCR technique, and the neural differentiation marker protein expression was evaluated by Immunocytochemistry technique. The data were analyzed by one-way ANOVA, using SPSS 13 software.
Findings: After 24 hours of treatment with nitric oxide and EMF, the rate of viability in all groups was significantly decreased compared to the control group. After 48 hours, EMF alone, as well as with low concentration of nitric oxide did not decrease the rate of viability and cell growth increased compared to the control group. In the group treated with high nitric oxide concentration along with EMF, MAP2 protein was expressed in the number of cells more than the control group and the one treated with EMF.
Conclusion: The electromagnetic field, along with its high concentration of nitric oxide, decreases the number of rat bone marrow mesenchymal stem cells and, by increasing cell size, gene expression and neural differentiation proteins marker facilitates their differentiation to nerve-like cells.
Volume 9, Issue 4 (12-2018)
Abstract
Aims: As a naturally occurring environmental factor as well as an external factor resulting from burgeoning technology, static magnetic field (SMF) has considerable effects on plants physiology. The effects of SMF on production of reactive oxygen species (ROS) have been shown in plant cells. The aim of the present research was to evaluate the redox system responses of soybean (Glycine max) to different intensities of SMF.
Materials and Methods: In the present experimental research, M7 soybean seeds in their vegetative phase (14 days) were treated with 20 and 30mT SMF for 4 day, 5 hours daily. The experiments were carried out in a completely randomized design with factorial and at least 3 replications. The data were analyzed by SPSS software, using one-way ANOVA.
Findings: The treatment of 30mT resulted in a reduction in fresh weight, total antioxidant activity, and total regenerative capacity and increased hydrogen peroxide, but did not affect the total contents of phenolic compounds and flavonoids. In the treatment of 20mT, the level of peroxide decreased, but the fresh weight, hydroxyl radical level, antioxidant activity, total phenolic compound, and flavonoids contents increased. The amounts of Fe2+ decreased in 20mT but increased with 30mT.
Conclusion: In the Soybean redox system, SMF of 20mT leads the electrons toward useful redox compounds like phenolic compounds and results in growth stimulation, while SMF of 30mT leads the surplus electrons to destructive compounds such as Fe2+, which results in decrease of the plant growth.
Volume 9, Issue 4 (12-2018)
Abstract
Aims: Regarding the treatment of cancer, due to the limitation in the use of high dose and resistance of cancer cells, it is necessary to use optimal methods that have high therapeutic efficacy and reduce the dose of radiation and medicine. The aim of the present research was to investigate toxicity of cisplatin under the influence of static magnetic field in susceptible and drug-resistant cell.
Materials and Methods: In the present experimental study, A2780-CP resistant cell classes and susceptible to A2780 cisplatin were investigated in the field and drug-treated cell groups compared to the drug-receiving group alone, and to determine the effect of static magnetic field and concentration of drug, 10mT for 24 hours and logarithmic drug concentration (1, 10, 50, 100, and 500mcg/ml) were used. Inhibitory concentration of 50% cell growth (IC50) was obtained for the cells in the absence and presence of the magnetic field after conversion of the absorption obtained in the ELISA from the MTT test to cytotoxicity percentage. Data were analyzed with Prism software using two-way ANOVA and T-test.
Findings: In the presence of a static magnetic field and different drug concentrations, a greater reduction in the percentage of In vivo cells was observed. IC50 values for A2780 cells in the absence and presence of magnetic fields were 27.69±9.58 and 8.96±1.48μg/ml for A2780-CP, and 61.61±8.03 and 9.58±3.13μg/ml, respectively.
Conclusion: The mortality rate of the cells treated with cisplatin under the influence of the magnetic field is more in susceptible and drug-resistant cells than that of only drug use. Drug-resistance decreases in the drug-resistant cell class in the presence of a magnetic field.
Volume 11, Issue 0 (10-2009)
Abstract
Objective: The environmental exposure to Magnetic Fields (MFs) may interact with biological systems. MFs are generated from various sources such as power lines, electric appliances at homes and offices, electrified transportation systems including urban railway systems and diagnostic devices such as Magnetic Resonance Imaging (MRI). There are some scientific evidences that imply the exposure to MFs are hazardous to our health and increases the rate of some cancers like leukemia. The biological consequences of exposure to MFs have been investigated from a variety of endpoints. However, most studies have been performed in vitro and have examined effects on cellular processes and its malfunction; such studies can be used as evidence of effects in vivo.
Materials and Methods: In this study Bone Marrow Stem Cells were grown in the absence and in the presence of a 15 mT Static Magnetic Field for 5 hours in order to determine any changes in cell cycle progression using the count of cells in different phases. The count of cells in a special phase of cell cycle indicates the length of that phase. The Static Magnetic Field was performed using a locally designed MF generator.
Results: A significant increase in the number of cells in G0/G1 was observed in comparison with the controls. Also the number of cells in G0/G1 in the cells treated with Hydrogen-Peroxide, as an oxidative agent, was significantly increased in Static MF.
Conclusion: Genetic material damages or mal-function of related proteins may cause these halts. Mfs have not enough energy to affect the biological molecules directly but the mechanism of free radical mediators is probable. These kinds of damages (direct or indirect) can permanently bring the cell cycle to a halt.
Volume 11, Issue 3 (10-2020)
Abstract
According to the formation and evolution of life along with static magnetic fields,the permanent exposure has given adaptive ability to beings. Therapeutic magnetism is one of the branches of complementary medicine which uses the low intensity and non-harmful magnetic fields to the body. By studying in infertile couples (20% male factor), the only cause of infertility and in 50% of cases it is considered as an intermediate factor. One of the influential factors in infertility in men is sperm. In the present study, normal specimens in the magnetic field under the intensities of 1,6 and 12 millitesla and at 1,3 and 5 h intervals.
Sperm movement rate was evaluated by CASA, as well as sperm viability, by eosin staining of necrosin and morphology by staining Papanicula. The results of this step on normal sperm showed a significant reduction in the sperm movement ,which that was not affected by the field.
Morphological studies also show that sperm motility is not affected by magnetic field.. the survival rate of sperm was affected by the magnetic field was significantly reduced, and the sperm morphology remained unchanged
Amin Hadidi, Mohammadreza Ansari,
Volume 12, Issue 1 (4-2012)
Abstract
In this study, a single bubble behavior in dielectric viscous fluid under the uniform magnetic field has been simulated numerically by using a level set method in two-phase bubbly flow. The two-phase bubbly flow considered to be laminar and homogenous. Deformation of the bubble was considered due to buoyancy and magnetic forces induced from the external applied magnetic field. A computer code was developed to solve the problem with flow field, interface of two-phases, and the magnetic field. The Finite Volume method was applied using SIMPLE algorithm to differentiate the governing equations. Using this algorithm enables us to calculate the pressure parameter which was eliminated by previous researchers due to complexity of the two-phase flow. The Finite Difference method was used to solve the magnetic field equation. The results outlined in the present study well agree with the existing experimental data and numerical results. The results show that the magnetic field affects and controls the shape, size, velocity and location of the bubble.
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.
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Volume 13, Issue 2 (5-2013)
Abstract
Terfenol-D, known as a giant magnetostrictive material, is used in many sensors such as force sensor. In these sensors, external force is measured due to variation of magnetic flux density passing through Terfenol-D. To improve the performance, Terfenol-D is exposed to bias magnetic field and mechanical pre-stress. In this paper, Effects of bias magnetic field and mechanical pre-stress on sensitivity and linear measurement range of a force sensor are studied and optimum values of them are recognized. Initially based on magnetomechanical coupling equations, theoretical model of sensor that includes effective parameters on sensitivity and linear measurement range is developed. Then using experimental set-up, magnetomechanical properties of Terfenol-D are investigated and values of essential parameters for theoretical model are extracted. Finally, employing theoretical model and experimental results, the response of sensor under dynamic external forces is simulated and effects of bias magnetic field and mechanical pre-stress on sensitivity and linear measurement range of the sensor are studied. Based on the obtained results, to increase sensitivity and linear measurement range of sensor, values of bias magnetic field and mechanical pre-stress should be relatively determined considering the amplitude of external force.
, Behzad Ghasemi,
Volume 13, Issue 3 (6-2013)
Abstract
Abstract- This paper presents the results of a numerical study on the natural convection in a right triangular enclosure filled with a water- Cu nanofluid in presence of a constant magnetic field. A heat source embedded on the bottom wall of enclosure, the inclined wall is cold and the other walls are adiabatic. Discretization of the governing equations are achieved through a finite volume method and solved with SIMPLE algorithm. The effects of parameters such as the Reyleigh number, the solid volume fraction, the Hartman number, length and location of heat source on flow and temperature fields and the heat transfer rate have been examined. The results show that increasing of Hartman number caused decreasing velocity of flow and heat transfer. Also, increase in solid volume fraction causes increase in heat transfer but its change in different Reyleigh number and Hartman number is not same. Therefore, the location of heat source in bottom of enclosure affects on the rate of heat transfer from enclosure.
, Behzad Ghasemi,
Volume 13, Issue 7 (10-2013)
Abstract
Abstract- Mixed convection flow of a water-copper nanofluid in a channel under magnetic field effects has been numerically investigated. The fluid flow and temperature fields as well as the heat transfer rate have been determined by solving the Navier-Stocks and energy equations. In this study, the effects of various parameters such as the Richardson number, the Hartmann number, the solid volume fraction and the channel angle on the thermal performance of the channel have been examined. The results showed that at high Richardson numbers, the heat transfer rate decreased as the Hartman number increased. It was also found that the heat transfer rate increased as the Richardson number, the solid volume fraction and the channel angle increased. The maximum flow reversal was observed to occur in a vertical channel.
Reza Nouri, Mofid Gorji-Bandpy, Davood Domiri Ganji,
Volume 13, Issue 14 (3-2014)
Abstract
In this paper, heat transfer in a sinusoidal channel filled with nanofluid under magnetic field effect is investigated numerically. The magnetic field transversely applied to the channel. Water as a base fluid and copper as nano particles were considered .The Maxwell-Garnetts model and Brinkman model for heat conduction coefficient and dynamic viscosity were used respectively. The effects of changing some parameters such as shape ,volume fraction , Hartmann number and Reynods number were considered. The results show that increasing in all mentioned parameters lead to increasing in Nusselt number. Volume fraction is mainly affect on maximum local Nusselt number in each channel’s wave while Hartmann number is affected minimum and maximum Nusselt number.
Masoud Kharati, Iman Jelodari,
Volume 14, Issue 3 (6-2014)
Abstract
In this research, two effective techniques to increase mixed convection heat transfer rate within an enclosure subjected to a transverse magnetic field are studied. In order to increase the heat transfer rate, the addition of Al2O3 nanoparticles is concerned as the first strategy and the change in magnetic field inclination angle is considered as the second. In this study, the left and right sides of the enclosure are kept at constant temperature while the top and bottom walls are adiabatic. In this work, the results are obtained with an in-house finite volume code. To validate the code, the results of the present code are compared to that of an existing correlation as well as those of previous works and good agreements are observed. In the present work, Richardson number varies from Ri=0.05 to Ri=50. Results show that the addition of solid particles may increase or decrease the heat transfer rate whereas the increase in magnetic field inclination angle mostly leads to increase in the heat transfer rate.
Afrasiab Raisi, Mehdi Davoudian,
Volume 14, Issue 5 (8-2014)
Abstract
In this paper, the natural convection of water-Al2O3 nanofluid in a square enclosure exposed to a magnetic field is numerically investigated. The enclosure is bounded by two isothermal vertical walls at different temperaturesof Th and Tc.The two horizontals walls of the enclosure are thermally insulated. A vertical plate (membrane separator) with a negligible thickness and a variable height is located in the middle of the chamber. Discretization of the governing equations are achived through a finit method and are solved using the SIMPLE algorithm. Based on the results of the numerical solution, the effects of the relevant parameters such as the dimensionless height of the membrane separator, Rayleigh number, the solid volume fraction and the Hartmann number on the flow field and the heat transfer rate are investigated. The results show that the heat transfer rate decreases with an increase of the dimensionless height of the membrane separator and an increase of the Hartmann number. The heat transfer rate, however, increases as the Rayleigh number increases. Depending on the Rayleigh number, the thermal performance of the enclosure is either improved or deteriorated as the solid volume fraction is increased.
Alireza Aghaei, Hoessin Khorasanizadeh, Ghanbar Ali Sheikhzadeh,
Volume 14, Issue 9 (12-2014)
Abstract
In this study, the effects of magnetic field on the flow field, heat transfer and entropy generation of Cu-water nanofluid mixed convection in a trapezoidal enclosure have been investigated, numerically. The side walls of the cavity are insulated, the top lid is cold and moving toward right or left and bottom wall is hot and the side walls angle from the horizon is 45˚. The results showed that with imposing the magnetic field and enhancing it, the nanofluid convection and the strength of flow decrease and the flow tends toward natural convection and finally toward pure conduction. For this reason, for all of the considered Reynolds numbers and volume fractions, by increasing the Hartmann number the average Nusselt number decreases. Furthermore, for any case with constant Reynolds and Hartmann numbers by increasing the volume fraction of nanoparticles the maximum stream function decreases. For all of the studied cases, entropy generation due to friction is negligible and the total entropy generation is mainly due to irreversibility associated with heat transfer and variation of the total entropy generation with Hartmann number is similar to that of the average Nusselt number. With change in lid movement direction at Reynolds number of 30 the average Nusselt number and total entropy generation are changed, but at Reynolds number of 1000 it has a negligible effect.
Behzad Ghasemi, Abbas Kasaeipoor, Afrasiab Raisi,
Volume 14, Issue 12 (3-2015)
Abstract
In this paper, the result of a numerical study on the natural convection in an inclined T shap cavity filled with Water-Cu nanofluid with the presence of a constant magnetic field was investigated. A heat source embedded on the bottom wall of enclosure, the upper wall is cold and the other walls are adiabatic. Discretization of the governing equations are achieved through a finite volume method and solved with SIMPLE algorithm. The Hartmann number has been varied from 0 to 80 and the cavity has been twisted under the angles between 0 to 90 degrees. The findings of study show that the effect magnetic field on the average Nusselt number is higher in high Reyleigh number. In Ra=105, the increase in nanofluid, to the Hartman number 20, contributes to decrease of the average number and in the Hartman number 40 and more, causes the average Nusselt number to increase. In Ra=106 , the increase in nanofluid, to the Hartman number 20, contributes to increase of the average number and in the Hartman number 40 and more, causes the average Nusselt number to decrease. The results also indicate that, the maximum heat transfer, in Ra=105 and Ra=106 accurse at 67.5° angle. the minimum heat transfer, in Ra=105 and Ra=106 accurse at 0° and 22.5° angle respectively.
Volume 15, Issue 2 (5-2024)
Abstract
Gene delivery using the force of a magnetic field is called magnetofection. The purpose of this study is the synthesis and characterization of magnetic iron oxide nanoparticles (Fe3O4) as the core of the transfer agent and to investigate the effect of alternating magnetic field on transfection efficiency. For this purpose, the first magnetic nanoparticles (MNP) were synthesized by coprecipitation method. The magnetic properties of the synthesized MNP were investigated by vibrating sample magnetometer (VSM), appearance characteristics, and zeta potential of the synthesized particles were evaluated using transmission electron microscopy (TEM) and dynamic light scattering (DLS). Then, using magnetic nanoparticles (MNP), polyethylene imine (PEI) and plasmid DNA containing luciferase reporter gene (pDNA), PEI-pDNA binary complex and MNP-PEI-pDNA ternary complex were synthesized. The complexes were evaluated using DLS and gel retardation techniques. The results of DLS and gel retardation technique showed that the complexes have a suitable surface charge and polyethyleneimine is well joined to pDNA and neutralized its negative charge. Finaly, human breast cancer cell lines (MCF-7) and Hek293T cells were transfected by ternary complex in the presence of 50 Hz alternating magnetic field. Cell viability was measured using the MTT test. The obtained results showed that the transfection efficiency in the cells that were transfected with the ternary complex in the presence of alternating magnetic field increased significantly compared to the control group, without any additional toxicity (P ≤ 0.05).
Pouyan Ramian, Mohammad Taeibi Rahni, Armen Adamian,
Volume 15, Issue 6 (8-2015)
Abstract
In this paper, natural convective heat transfer of nanofluids in a uniform magnetic field between the square cavity and inner cylinder, was simulated via Lattice Boltzmann Method. The inner cylinder in square shape, diamond, and circular has been examined. Square cavity walls and inner cylinder surfaces are at a constant cold and warm temperature, respectively. The flow, temperature, and magnetic field is calculated with solving flow, temperature, and magnetic distribution functions simultaneously. D2Q9 lattice arrangement for each distribution function is used. The results clearly show the behavior of fluid flow and heat transfer between the cavity and the cylinder. The results have been validated with available valid results showing relatively good agreement. The effects of Rayleigh number, Hartmann number, void fraction and type of nanoparticles on natural convective heat transfer are investigated. This study shows that for all three geometries used with the same void fraction, type of nanofluid, and Rayleigh number, natural convective heat transfer decreases with Hartmann number. Also, when Hartmann number was had fixed, natural convective heat transferwas increased with Rayleigh number. Thus, to select the right geometry for optimum natural convective heat transfer, our needs to pay special attention to Hartmann and Rayleigh numbers. In addition, viod fraction and type of nanofulid can affect heat transfer directly.
Hadi Kargar Sharifabad, Mohammad Falsafi,
Volume 15, Issue 6 (8-2015)
Abstract
This numerical study forced convective heat transfer ferrofluid within a circular copper tube includes portions of the electromagnetic isolation under an alternating magnetic field is performed. Laminar flow through a tube under uniform and thermal flux passes. Intensifying transfer of particles and velocity increase in the boundary layer using nanoparticles to increase the effect of magnetic field onto more heat transfer, the main goal is. Convection regimens resulting from complex interactions between magnetic nanoparticles were studied under different conditions, with the concentration and volume of different the heat transfer process under different frequencies of the applied magnetic field were studied. Magnetic field effects on the convective heat transfer coefficient at different Reynolds numbers and volume percentages have been studied. Also when the electromagnetic is insulated pipe parts of have been studied and have been compared with the modes without insulation. Increase the frequency and volume fraction of magnetic field, resulting in increased heat transfer were better. Magnetic field at low Reynolds numbers have shown a greater impact. For prove the numerical results evaluated in this research work has been studied experimentally. The results showed that the modeling data were in very good agreement with experimental data.
