Review on Electromagnetic Stimulation of Alive Tissues

2016 ◽  
Vol 0 (0) ◽  
Author(s):  
Oana Drosu ◽  
Marilena Stanculescu
Keyword(s):  
Magnetic Field ◽  
Chemical Transport ◽  
Biological Tissues ◽  
The Body ◽  
Excitable Cells ◽  
Electromagnetic Stimulation ◽  
Excitable Tissue ◽  
First Case ◽  
The Magnetic Field ◽  
Stimulation Of

AbstractThe electric, magnetic or electromagnetic phenomena that occur in the biological tissues include: the behavior of excitable tissue (the sources), the electric currents and potentials in the volume conductor, the magnetic field at and beyond the body, the response of excitable cells to electric and magnetic field stimulation (through changes in their electrical activity, changes of chemical transport through cell membrane); the intrinsic electric and magnetic properties of the tissue. This paper presents an overview of fundamental phenomena occurring in the application of stimuli with a future purpose of focusing on several models of external electromagnetic stimulation. The target is to create models of the electroconductive anatomy of some alive tissues will be proposed, in order to investigate the fields and the currents generated by the on-set of an electric field (in the first case) or a time-variant magnetic field (in the second case) or the superposition of the two types of stimuli.

Preliminary Results Using a Magnet-Embedded Compression Garment after Liposuction Surgery

2005 ◽  
Vol 22 (3) ◽  
pp. 165-171
Author(s):  
Douglas D. Dedo ◽  
Theresa A. Biemer
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Biological Tissues ◽  
The Body ◽  
Whole Body ◽  
Compression Garment ◽  
Preliminary Results ◽  
Significant Difference ◽  
Magnetic Strength ◽  
The Magnetic Field

Introduction: Magnetic fields have been touted as a cure and method of treatment for a variety of illnesses and medical conditions, and revenues from the sales of health-related magnetic products reportedly add up to billions of dollars. Magnets and the magnetic fields they create are marketed as having no associated risks; however, the medical community questions their benefits, and the Food and Drug Administration has not approved static magnetic fields for the treatment of any medical ailment. Methods and Materials: This study evaluated the postoperative effects of a magnetic garment on patients undergoing liposuction. For each standard postoperative compression garment, one half was fitted with elasticized magnetic neoprene material and the other half with nonmagnetized neoprene. The manufacturer sent the garments to the authors without identifying which sides had the active magnetic strips. Results: Preliminary results of this study showed no statistical difference in bruising, swelling, or postoperative results between the magnetized and the nonmagnetized treated areas. Although theories abound concerning the effects of magnetic field on optimizing the supply of nutrients and oxygen to the magnetic field area, this clinical study did not support any significant difference in the rate of wound healing. However, this study did show that pain and tenderness were markedly reduced on the side covered with the magnetic field. Eight of the 9 patients noted a decrease in pain and discomfort postoperatively on the left side, which was the half of the garment with the magnetized neoprene strips. The greatest reduction in pain was observed in the first 24 hours of treatment with the magnets, and the improvement increased with the passage of time. This study also found a reduction in the amount of analgesics needed by the patients using magnets during the treatment period. Discussion: Magnetic volume is important in delivering a therapeutic effect. Having more volume means that more tissues are experiencing the magnetic field. The neoprene magnetic strength is low in gauss units but high in Maxwell units because of the configuration of the north-south pole orientation described. Conversely, a unipolar magnet with a high magnetic strength delivers a low magnetic volume and is not considered important for therapeutic use. To date, researchers are uncertain whether low-level magnetic fields are hazardous to biological tissues. There has been some concern about safety issues for long-term whole-body exposure, but this may not be applicable to brief exposure to small areas of the body associated with static magnets. The theoretical basis for the physiologic response from static magnets has not been clearly identified. A search and review of the medical literature resulted in a limited number of studies. Few studies have evaluated magnets for relief of chronic pain for disease states and musculoskeletal pain, and even fewer have addressed mechanism of action.

scholarly journals The effect of simplifications of a numerical mesh on the results of electromagnetic analysis of the Nuclotron-type cable

2018 ◽  
Vol 177 ◽  
pp. 08004
Author(s):  
Łukasz Tomków
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Current Density ◽  
Electric Current Density ◽  
Electromagnetic Analysis ◽  
First Case ◽  
Single Region ◽  
The Magnetic Field

The model of a single Nuclotron-type cable is presented. The goal of this model is to assess the behaviour of the cable under different loads. Two meshes with different simplifications are applied. In the first case, the superconductor in the cable is modelled as single region. Second mesh considers individual strands of the cable. The significant differences between the distributions of the electric current density obtained with both models are observed. The magnetic field remains roughly similar.

COMPARISON OF CARDIAC MAGNETIC FIELD DISTRIBUTIONS DURING DEPOLARIZATION AND REPOLARIZATION

2003 ◽  
Vol 13 (12) ◽  
pp. 3783-3789 ◽  
Author(s):  
F. E. SMITH ◽  
P. LANGLEY ◽  
L. TRAHMS ◽  
U. STEINHOFF ◽  
J. P. BOURKE ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Field Distribution ◽  
Normal Subjects ◽  
The Body ◽  
Magnetic Field Distribution ◽  
T Wave ◽  
High Magnetic Field Strength ◽  
The Magnetic Field

Multichannel magnetocardiography measures the magnetic field distribution of the human heart noninvasively from many sites over the body surface. Multichannel magnetocardiogram (MCG) analysis enables regional temporal differences in the distribution of cardiac magnetic field strength during depolarization and repolarization to be identified, allowing estimation of the global and local inhomogeneity of the cardiac activation process. The aim of this study was to compare the spatial distribution of cardiac magnetic field strength during ventricular depolarization and repolarization in both normal subjects and patients with cardiac abnormalities, obtaining amplitude measurements by magnetocardiography. MCGs were recorded at 49 sites over the heart from three normal subjects and two patients with inverted T-wave conditions. The magnetic field intensity during depolarization and repolarization was measured automatically for each channel and displayed spatially as contour maps. A Pearson correlation was used to determine the spatial relationship between the variables. For normal subjects, magnetic field strength maps during depolarization (R-wave) showed two asymmetric regions of magnetic field strength with a high positive value in the lower half of the chest and a high negative value above this. The regions of high R-wave amplitude corresponded spatially to concentrated asymmetric regions of high magnetic field strength during repolarization (T-wave). Pearson-r correlation coefficients of 0.7 (p<0.01), 0.8 (p<0.01) and 0.9 (p<0.01) were obtained from this analysis for the three normal subjects. A negative correlation coefficient of -0.7 (p<0.01) was obtained for one of the subjects with inverted T-wave abnormalities, suggesting similar but inverted magnetic field and current distributions to normal subjects. Even with the high correlation values in these four subjects, the MCG was able to identify differences in the distribution of magnetic field strength, with a shift in the T-wave relative to the R-wave. The measurement of cardiac magnetic field distribution during depolarization and repolarization of normal subjects and patients with clinical abnormalities should enable the improvement of theoretical models for the explanation of the cardiac depolarization and repolarization processes.

scholarly journals Magnetic field disturbances in the sheath region of a super-sonic interplanetary magnetic cloud

2008 ◽  
Vol 26 (10) ◽  
pp. 3153-3158 ◽  
Author(s):  
E. Romashets ◽  
M. Vandas ◽  
S. Poedts
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Storms ◽  
Magnetic Cloud ◽  
The Body ◽  
Magnetic Clouds ◽  
Shock Surface ◽  
Sheath Region ◽  
Magnetic Field Magnitude ◽  
The Magnetic Field ◽  
Magnetic Disturbances

Abstract. It is well-known that interplanetary magnetic clouds can cause strong geomagnetic storms due to the high magnetic field magnitude in their interior, especially if there is a large negative Bz component present. In addition, the magnetic disturbances around such objects can play an important role in their "geo-effectiveness". On the other hand, the magnetic and flow fields in the CME sheath region in front of the body and in the rear of the cloud are important for understanding both the dynamics and the evolution of the interplanetary cloud. The "eventual" aim of this work is to calculate the magnetic field in this CME sheath region in order to evaluate the possible geo-efficiency of the cloud in terms of the maximum |Bz|-component in this region. In this paper we assess the potential of this approach by introducing a model with a simplified geometry. We describe the magnetic field between the CME shock surface and the cloud's boundary by means of a vector potential. We also apply our model and present the magnetic field distribution in the CME sheath region in front of the body and in the rear of the cloud formed after the event of 20 November 2003.

Relation between wave speeds in the crust of dense magnetic stars

1978 ◽  
Vol 364 (1719) ◽  
pp. 537-552 ◽  
Keyword(s):  
Magnetic Field ◽  
Initial Pressure ◽  
The Body ◽  
Perfect Conductor ◽  
Initial State ◽  
Wave Speeds ◽  
Magnetic Stars ◽  
Arbitrary Strength ◽  
The Magnetic Field ◽  
Relativistic Framework

By studying, within the relativistic framework, the propagation of so-called infinitesimal discontinuities throughout a magnetized elastic perfect conductor in an initial state of high hydrostatic pressure p 0 and in the presence of a magnetic field of arbitrary strength, it is proven that there hold universal relations (i. e., that do not depend on the exact equation of state of the body) between the speeds U f and U s of so-called fast and slow magnetoelastic modes. These results, which should hold true in the crust of dense magnetic stars, have the following form. If A 0 is the relativistic Alfvén number of the initial state and a 0 is the sound speed of a fictitious relativistic perfect fluid whose law of compression would yield the initial pressure p o , then (with nondimensional speeds) U 2 / f = 4/3[ U 2 s (1+ A 2 0 ]+( a 2 0 -4/3 A 2 0 ) for a propagation along the magnetic field and U 2 f (1+ A 2 0 )=4/3 U 2 s +( a 2 0 + A 2 0 ) for a propagation in a direction orthogonal to the magnetic field. These results generalize previous results obtained in relativistic elasticity by Carter and Maugin.

Superconductors With Structured Surfaces: Fields and Currents

1987 ◽  
Vol 101 ◽  
Author(s):  
Z.C. Wu ◽  
Daniel A. Jelski ◽  
Thomas F. George
Keyword(s):  
Magnetic Field ◽  
The Other ◽  
Ginzburg Landau ◽  
Landau Model ◽  
Structured Surfaces ◽  
Field Parallel ◽  
First Case ◽  
The Magnetic Field ◽  
Effect Of Structure ◽  
Effect Of Surface

ABSTRACTThis paper discusses the behavior of currents and fields along a structured superconductor. First the effect of surface structure on supercurrents is investigated. Then the effect of structure on the critical nucleation field is discussed in two cases, one with the magnetic field parallel to the ripples and the other with the field parallel to the grating wavenumber. In the first case, it is found that the critical field is reduced as a function of grating height, whereas in the latter case it is increased. Finally, the relevance of this work for laser-induced chemistry above a superconducting surface is discussed. The Ginzburg-Landau model is used throughout.

On the determination of the size of the Earth’s core from observations of the geomagnetic secular variation

1981 ◽  
Vol 374 (1756) ◽  
pp. 15-33 ◽  
Keyword(s):  
Magnetic Field ◽  
Secular Variation ◽  
Magnetic Data ◽  
Time Interval ◽  
Perfect Conductor ◽  
Geomagnetic Secular Variation ◽  
The Core ◽  
First Case ◽  
Fractional Error ◽  
The Magnetic Field

When the magnetic field of a planet is due to self-exciting hydromagnetic dynamo action in an electrically conducting fluid core surrounded by a poorly-conducting ‘mantle', a recently proposed method (Hide 1978,1979) can in principle be used to find the radius r c of the core from determinations of secular changes in the magnetic field B in the accessible region above the surface of the planet, mean radius r s , with a fractional error in r c of the order of, but somewhat larger than, the reciprocal of the magnetic Reynolds number of the core. It will be possible in due course to apply the method to Jupiter and other planets if and when magnetic measurements of sufficient accuracy and detail become available, and a preliminary analysis of Jovian data (Hide & Malin 1979) has already given encouraging results. The ‘magnetic radius’ ̄r̄ c of the Earth’s molten iron core has been calculated by using one of the best secular variation models available (which is based on magnetic data for the period 1955-75), and compared with the ‘seismological’ value of the mean core radius, r c = 3486 ± 5 km. Physically plausible values of r̄ c are obtained when terms beyond the centred dipole ( n = 1) and quadrupole ( n = 2) in the series expansion in spherical harmonics of degree n = 1,..., ^ n ,..., n * are included in the analysis (where 2 ≼ ^ n ≼ n *≼ ∞). Typical values of the fractional error ( r̄ c - r c ) / r c amount to between 0.10 and 0.15. Somewhat surprisingly, this error apparently depends significantly on the value of the small time interval considered; the error of 2% found in the first case considered, for which ^ n — n * = 8 and for the time interval 1965-75, is untypically low. These results provide observational support for theoretical models of the geomagnetic secular variation that treat the core as an almost perfect conductor to a first approximation except within a boundary layer of typical thickness much less than 1 km at the core-mantle interface.

The distortion of a magnetic field by the flow of a conducting fluid past a circular cylinder

1965 ◽  
Vol 22 (3) ◽  
pp. 561-578 ◽  
Author(s):  
R. Seebass ◽  
K. Tamada
Keyword(s):  
Magnetic Field ◽  
Integral Equation ◽  
Circular Cylinder ◽  
Potential Flow ◽  
Uniform Magnetic Field ◽  
The Body ◽  
Flow Potential ◽  
Field Lines ◽  
The Magnetic Field ◽  
Rear Stagnation Point

The distortion of a uniform magnetic field, aligned with the flow at infinity, by the potential flow of an inviscid conductor about a circular cylinder is determined. Potential flow of the fluid occurs when the interaction parameter is small; this is the case studied here. In the flow-potential and stream-function plane the problem may be formulated as a singular integral equation. Solutions of this equation show that for small fluid conductivities the magnetic field lines are distorted in the sense of being dragged along by the motion of the fluid. This process continues as the conductivity increases, with fewer and fewer of the magnetic field lines entering the body. For large conductivity this reduced flux of field lines enters over most of the body surface and exits in the neighbourhood of the rear stagnation point; behind the body there is a jet-like structure of magnetic field lines.

scholarly journals The influence of the magnetic field on the ionized gas flow adjacent to the porous wall

2010 ◽  
Vol 14 (suppl.) ◽  
pp. 183-196
Author(s):  
Slobodan Savic ◽  
Branko Obrovic ◽  
Milan Despotovic ◽  
Dusan Gordic
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Gas Flow ◽  
Great Influence ◽  
Porous Wall ◽  
Boundary Layer Separation ◽  
The Body ◽  
Ionized Gas ◽  
Friction Function ◽  
The Magnetic Field

This paper studies the influence of the magnetic field on the planar laminar steady flow of the ionized gas in the boundary layer. The present outer magnetic field is homogenous and perpendicular to the body within the fluid. The gas of the same physical characteristics as the gas in the main flow is injected (ejected) through the contour of the body. The governing boundary layer equations for different forms of the electroconductivity variation law are transformed, brought to a generalized form and solved numerically in a four-parametric approximation. It has been determined that the magnetic field, through the magnetic parameter, has a great influence on certain quantities and characteristics of the boundary layer. It has also been shown that this parameter has an especially significant influence on the non-dimensional friction function, and hence the boundary layer separation point.

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