Flow of a biomagnetic viscoelastic fluid:application to estimation of blood flow in arteries during electromagnetic hyperthermia,a therapeutic procedure for cancer treatment

The paper deals with the theoretical investigation of a fundamental problem of biomaguetic fluid flow through a porous medium subject to a magnetic field by using the principles of biomagnetic fluid dynamics （BFD）. The study pertains to a situation where magnetization of the fluid varies with temperature. The fluid is considered to be non-Newtonian, whose flow is governed by the equation of a second-grade viscoelastic fluid. The walls of the channel are assumed to be stretchable, where the surface velocity is proportional to the longitudinal distance from the origin of coordinates. The problem is first reduced to solving a system of coupled nonlinear differential equations involving seven parameters. Considering blood as a biomagnetic fluid and using the present analysis, an attempt is made to compute some parameters of the blood flow by developing a suitable numerical method and by devising an appropriate finite difference scheme. The computational results are presented in graphical form, and thereby some theoretical predictions are made with respect to the hemodynamical flow of the blood in a hyperthermal state under the action of a magnetic field. The results clearly indicate that the presence of a magnetic dipole bears the potential so as to affect the characteristics of the blood flow in arteries to a significant extent during the therapeutic procedure of electromagnetic hyperthermia. The study will attract the attention of clinicians, to whom the results would be useful in the treatment of cancer patients by the method of electromagnetic hyperthermia.

Non-Newtonian biomagnetic fluid flow through a stenosed bifurcated artery with a slip boundary condition

The effects of a velocity slip and an external magnetic field on the flow of biomagnetic fluid(blood)through a stenosed bifurcated artery are investigated by using ANSYS FLUENT.Blood is regarded as a non-Newtonian power-law fluid,and the magnetization and electrical conductivity are considered in the mathematical model.The no-slip condition is replaced by the first-order slip condition.The slip boundary condition and magnetic force are compiled in the solver by the user-defined function(UDF).Numerical solutions are obtained by the finite volume method based on a nonuniform grid structure.The accuracy and efficiency of the solver are verified through a comparison with the literature.The results are presented graphically for different parameter values,and the effects of the magnetic number,the magnetic source position,the vascular obstruction ratio,the slip parameter,and the power-law index on the flow and temperature fields are illustrated.

Biomagnetic techniques for evaluating gastric emptying,peristaltic contraction and transit time

Biomagnetic techniques were used to measure motility in various parts of the gastrointestinal(GI) tract,particularly a new technique for detecting magnetic markers and tracers.A coil was used to enhance the signal from a magnetic tracer in the GI tract and the signal was detected using a fluxgate magnetometer or a magnetoresistor in an unshielded room.Estimates of esophageal transit time were affected by the position of the subject.The reproducibility of estimates derived using the new biomagnetic technique was greater than 85% and it yielded estimates similar to those obtained using scintigraphy.This technique is suitable for studying the effect of emotional state on GI physiology and for measuring GI transit time.The biomagnetic technique can be used to evaluate digesta transit time in the esophagus,stomach and colon,peristaltic frequency and gastric emptying and is easy to use in the hospital setting.

Three-dimensional biomagnetic Maxwell fluid flow over a stretching surface in presence of heat source/sink

The present paper deals with the study of three-dimensional boundary layer flow of biomagnetic Maxwell fluid over a plane horizontal surface stretched linearly along two mutually perpendicular directions. Basic principles of magnetohydrodynamics (MHD) and ferro-hydrodynamics (FHD) have been employed. The effect of heat generation/absorption has been taken into consideration. The study is theoretical and is conducted by using a combination of approximate and numerical techniques. By using the method of similarity transformation, the governing nonlinear partial differential equations are converted into a set of coupled ordinary differential equations. In the sequel, a suitable numerical method has been developed to solve the coupled differential equations. The accuracy of the numerical method has been checked by comparing the numerical results with those of an earlier study reported in available literatures. Effects of various parameters involved in the study, viz. the magnetohydrodynamic and ferromagnetic parameters, Deborah number, stretching ratio and heat generation on the fluid flow profiles are investigated and the results have been presented graphically. Variations of the skin friction, heat transfer rate and relative wall pressure with change in hydrodynamic and ferromagnetic parameters have also been illustrated. It is found that due to the influence of the Kelvin force, the velocity component in xx-direction is greater than the corresponding one in the hydrodynamic case, but the opposite is true for the velocity component in the yy-direction. We also found that the temperature of the fluid for hydrodynamic flow is greater than that for MHD or FHD flow. It is even greater for BFD flows. The numerical results of the study reveal that the characteristics of blood flow are significantly affected by the presence of a magnetic field.

Giant magneto-impedance sensor with working point selfadaptation for unshielded human bio-magnetic detection

Background Compared with traditional biomagnetic field detection devices,such as superconducting quantum interference devices(SQUIDs)and atomic magnetometers,only giant magneto impedance(GMI)sensors can be applied for unshielded human brain biomagnetic detection,and they have the potential for application in next-generation wearable equipment for brain-computer interfaces(BCIs).Achieving a better GMI sensor without magnetic shielding requires the stimulation of the GMI effect to be maximized and environmental noise interference to be minimized.Moreover,the GMI effect stimulated in an amorphous filament is closely related to its working point,which is sensitive to both the external magnetic field and the drive current of the filament.Methods In this paper,we propose a new noise reducing GMI gradiometer with a dual-loop self-adapting structure.Noise reduction is realized by a direction-flexible differential probe,and the dual-loop structure optimizes and stabilizes the working point by automatically controlling the external magnetic field and drive current.This dual-loop structure is fully program controlled by a micro control unit(MCU),which not only simplifies the traditional constant parameter sensor circuit,saving the time required to adjust the circuit component parameters,but also improves the sensor performance and environmental adaptation.Results In the performance test,within 2 min of self-adaptation,our sensor showed a better sensitivity and signal-to-noise ratio(SNR)than those of the traditional designs and achieved a background noise of 12 pT/√Hz at 10 Hz and 7pT/√Hz at 200 Hz.Conclusion To the best of our knowledge,our sensor is the first to realize self-adaptation of both the external magnetic field and the drive current.

Comparative analysis of current and magnetic multipole graphical models

In recent year, a multipole graphical model, which is constructed by using individual MCG measurements based on the equivalent current dipole (ECD) or equivalent magnetic dipole (EMD) source model, has been developed with the aim of instead of the volume conductor model in the inverse solution of cardiac source estimation. In this paper, two graphical models known as the double magnetic dipole source model (DMD) and the dual current dipole source model (DCD) are introduced. The simulation results and the comparison of two evaluation criteria, i.e. average GOF (Goodness of Fit) and average RMSE (Root Mean Square Error), indicated that both multipole graphical models can provide a good representation of dynamic magnetic field from the noninvasively detected MCG- recordings, even when the heart is of the dilation. The time-averaged sources localization error and the RMSE for both models are demonstrated, and the characteristic of two multipole models is discussed.

Changes in Environmental Parameters and Their Impact on Forest Growth in Northern Eurasia

We performed an empirical investigation of forest growth for two types of forests in northern Eurasia (larches and spruces) in order to show that the sensitivity of trees to the variable climate and geomagnetic field can be seen even under the large-scale average. The main purpose of this research was to model a forest growth rate V for each forest type on the basis of several environmental parameters influencing the tree growth in a high degree and to find the differences and similarities of the larches and spruces’ response to changing environment. We showed that V, which is related to the annual tree-ring width, could be derived from the Normalized Difference Vegetation Index (NDVI) data. Averaged yearly by species for 1982-2006, it displayed a long-term decrease (most likely related to the global climate change) as well as short-term variations with periods of 2.2, 4 and 8 years. A composite function method was used for modeling. We selected several tree growth drivers (the temperature, precipitation, insolation and the geomagnetic field intensity) that were highly correlated with V, and a function was modeled that described the behavior of V. The correlation coefficients between the derived function and experimental time series were 0.8 for larches and 0.9 for spruces. Compared with spruces, larches demonstrated higher thermo-sensitivity. A loss of tree sensitivity to temperature changes is puzzling for dendroclimatology, as a similar process might have occurred during previous periods of sharp global climate changes (as observed currently). Sensitivity of trees to geomagnetic field changes is confirmed both at long- and short-timescales. Spruces are found to be more magnetosensitive than larches.

Cardiac electrical activity imaging of patients with CRBBB or CLBBB in magnetocardiography

A new method for the imaging of cardiac electrical activity in patients with complete right bundle branch block （CRBBB） or complete left bundle branch block （CLBBB） is investigated using magnetocardiographic recordings of the surface of the body. This is based on the assumption that an equivalent single-current dipole moves along the unblocked bundle branch, whose position in the measurement plane is expressed in terms of the maximum and minimum, as well as the maximum gradient value of the measured magnetic field. The trajectory of the moving dipole on the measurement plane is indicative of theexcitation conduction of the CRBBB or CLBBB subject during ventricular depolarization and repolarization, which is deduced by comparing each change between the dipole moment and the maximum current density in a corresponding pseudo-current density map. In summary, this method can distinguish CRBBB from CLBBB subjects by means of the dipole depth and two dipole moment components. The possibility of visualizing the excitation conduction in a CRBBB or CLBBB subject during ventricular depolarization and repolarization is then discussed.

A Look to the Bioenergetic Medicine from the Human Physiology

Objective: To relate biochemistry of the human physiology with the application of the bioenergetic medicine. Methods:Search about the topic in the last 5 years and present a general view of some biochemical processes that allow to apply thebioenergetic medicine, due to the need to open new alternatives based on holistic methods. Conclusions: It was based on the searchof articles in the Virtual Library in Health (Spanish: BVS) and using the key words: bioenergetic medicine, vibration, energy,breathing, chakras, biomagnetism, translated into the quality of life’s improvement and the welfare of human being.

EFFECT OF EXTERNAL MAGNETIC FIELD ON INDUCING CALLUS OF RICE (Oryza sativa subsp.indica)

As early as the 1960s, Boe et al., Pittman et al. and Murr et al. have reported that the magnetic field can accelerate the maturity and growth of plants. However, the advance of this investigation about the biomagnetic effects on

THE EFFECT OF PULSE MAGNETIC FIELD ON SEVERAL KINDS OF CELLS

Ⅰ. INTRODUCTION Although some results have been obtained from studies about the influence of a weak magnetic field or constant magnetic field on the bodies of human beings, rats and flies or magnetocardiogram and so on, the study of the relationship between the pulse magnetic field and the cell growth has not been reported.