Application Of Static Magnetic Field Research Articles

Effect of static magnetic field on pain associated with frozen shoulder

To examine the effectiveness of application of a static magnetic field (SMF) in reducing pain associated with frozen shoulder, a pathophysiological study of shoulder pain was performed using thermography and deep body thermometry in conjunction with the patients' subjective and objective symptoms. A total of 40 patients (18 men and 22 women; age range, 27 to 83 years; mean age, 57.3 years) with pain associated with frozen shoulder for a duration of 1 week to 36 years (mean, 7 years) were investigated. The subjective and objective symptoms were evaluated with inspection and palpation in conjunction with a visual analogue scale. Patients were randomly assigned to be exposed to active or dummy magnets in a doubleblind test. Active magnets [Ferrite Magnets (130 ± 10 mT, 15 mm in diameter and 7.2 mm in height)] were applied externally to the painful area. In other patients, dummy magnets (0 mT) were applied externally as a placebo. All patients wore 12 pieces of active or dummy magnets for 3 weeks, after which the magnets were removed. Before the treatment, the skin temperature of the painful area was generally lower than that of a healthy or painless area. Upon application of the active magnets, the subjective and objective symptoms significantly improved at 3 weeks, accompanied by an increase in the skin temperature of the painful area. The pain relief persisted in the patients with shoulder pain up through 1 week after removal of the active magnets. These findings suggest that SMF application gradually increases the blood circulation in areas with ischemic pain, thereby improving the subjective and objective symptoms.

Static magnetic field influence on rat brain function detected by heart rate monitoring.

The aim of the present study was to identify the effects of a static magnetic field (SMF) on rat brain structures that control autonomic functions, specifically heart rate and heart rhythmicity. The experiments were carried out on 44 male Wistar rats under ketamine-xylazine anesthesia. SMF was induced using samarium-cobalt fused magnets (20 x 20 x 10 mm in size) placed bitemporally. Magnetic induction intensity was 100 mT on the surface of the head. Duration of magnetic field application was 15 min. An electrocardiogram was recorded from limb lead II, and both heart rate (average duration of cardiac cycles) and heart rhythmicity were analyzed before and after SMF application. SMF evoked changes in both heart rate and rhythm in 80% of the animals; the predominant effects were bradycardia and disappearance of respiratory sinus arrhythmia. However, the effectiveness of SMF in large measure depends on both functional peculiarities and functional activities of brain autonomic centers.

Study on Application of Static Magnetic Field for Adjuvant Arthritis Rats.

In order to examine the effectiveness of the application of static magnetic field (SMF) on pain relief, we performed a study on rats with adjuvant arthritis (AA). Sixty female Sprague–Dawley (SD) rats (age: 6 weeks, body weight: approximately 160 g) were divided into three groups [SMF-treated AA rats (Group I), non-SMF-treated AA rats (Group II) and control rats (Group III)]. The SD rats were injected in the left hind leg with 0.6 mg/0.05 ml Mycobacterium butyrium to induce AA. The rats were bred for 6 months as chronic pain model. Thereafter, the AA rats were or were not exposed to SMF for 12 weeks. We assessed the changes in the tail surface temperature, locomotor activity, serum inflammatory marker and bone mineral density (BMD) using thermography, a metabolism measuring system and the dual-energy X-ray absorptiometry (DEXA) method, respectively. The tail surface temperature, locomotor activity and femoral BMD of the SMF-exposed AA rats were significantly higher than those of the non-SMF-exposed AA rats, and the serum inflammatory marker was significantly lower. These findings suggest that the pain relief effects are primarily due to the increased blood circulation caused by the rise in the tail surface temperature. Moreover, the pain relief effects increased with activity and BMD of the AA rats.

Static Magnetic Field and Verapamil Effect on Baroreflex Stimulus-Induced Microcirculatory Responses

Arterial baroreceptors importantly evolved in blood pressure regulation with significant clinical consequences. We studied the less explored direct effect of the arterial baroreflex on regional microcirculation. Fifty-one experiments were performed in conscious rabbits to investigate the relationship between microcirculation and arterial baroreflex subjected to stimulation with either 0.35 T static magnetic field (SMF) and/or the calcium channel blocker, verapamil. Mean femoral artery blood pressure (MAP), heart rate (HR), and a microphotoelectric plethysmogram (MPPG) of the ear lobe skin microcirculatory network were simultaneously recorded during 120 and 140 min experiments. Baroreflex sensitivity (BRS) was assessed on the basis of the HR/MAP relationship during vasodilator (sodium nitroprusside) or vasoconstrictor (phenylephrine) drug i.v. bolus injections and by power spectral analysis estimating the transfer function from MAP to HR before and after 40 min of 0.35 T SMF (Nd2-Fe14-B magnets) local exposure to sinocarotid baroreceptors and/or verapamil infusion (20 µg/kg/min). We found significant positive correlation between MPPG and BRS (R = 0.44, p = 0.02, n = 28) indicating participation of the baroreflex regulatory mechanism in microcirculation. Both SMF and verapamil increased baroreflex stimulus-induced microcirculatory responses (p < 0.01) indicating augmentation of baroreceptor capacity to regulate microcirculation. The simultaneous application of SMF and verapamil did not affect microcirculatory response suggesting Ca2+ channels as a possible site of SMF impact. Pharmacological and nonpharmacological modulation of the baroreflex stimulus-induced microcirculatory responses implies new possibilities to improve microcirculation in target organs with potential clinical implementation.

Verapamil protective effect on natural and artificial magnetic field cardiovascular impact

Previously we found an opposite effect of artificial static magnetic field (SMF) and natural geomagnetic field (GMF) on arterial baroreceptors. A 0.35 T SMF increased baroreflex sensitivity (BRS), whereas GMF disturbance decreased BRS. Here, we investigated interrelated impacts on arterial baroreceptors of 0.35 T SMF, generated by Nd(2)-Fe(14)-B alloy magnets, GMF, and verapamil, a Ca(2+) channel blocking agent. We measured BRS in rabbits before and after local SMF exposure of sinocarotid baroreceptors or after simultaneous SMF and verapamil application, in conjunction with geomagnetic disturbance during actual experimental run (determined by K-index) and geomagnetic disturbance over the preceding 24 h of each experiment (A(k)-index). BRS was estimated from peak responses of mean arterial pressure (MAP) and heart rate, expressed as percentages of the resting values preceding each pair of pressure (phenylephrine) and depressor drug (nitroprusside) injections. Prior to verapamil and/or SMF application we found a significant positive correlation of K-index with MAP (t = 2.39, P =.021, n = 44), but negative with BRS (t = -4.60, P =.0003, n = 44), and found a negative correlation of A(k)-index with BRS (t = -2.7, P = 0.01, n = 44). SMF induced an increase in BRS (0.79 +/- 0.1 vs. 1.15 +/- 0.1 bpm%/mmHg%, initial value vs. SMF exposure, P <.0002, n = 26). Verapamil infusion blocked the SMF and GMF effect on BRS, indicating Ca(2+) channels as a possible site of both fields' impact. SMF and GMF probably affect baroreceptor sensory transduction, modulating baroreceptor membranes' Ca(2+) channel permeability.

Effect of Static Magnetic Field Application on the Mass Transfer in Sequence Slab Continuous Casting Process

A mathematical model has been developed to analyze the mass transfer in the sequence continuous casting process with the static magnetic field. The induced electromagnetic force is obtained by solving simultan eousequations for the momentum and the electromagnetic field. The application of static magnetic field affects the mass transfer by changing the flow field in the strand. The results of numerical calculation show a reasonable agreement of the calculated relative concentration of mixed steel with the measured one. The mixing of molten steel in the low part of the mold is significantly suppressed by the static magnetic field, and composition of new grade steel along the slab length in the transition zone increases significantly. The distribution of relative concentration averaged at cross section changes from parabolic to integral symbolic-like along the slab length, and the transition length is reduced about 50% by applying the magnetic field of 0.5 T.

Modeling of molten metal flow in a continuous casting process considering the effects of argon gas injection and static magnetic-field application

A mathematical model has been developed to analyze molten metal flow, considering the effects of argon gas injection and static magnetic-field application in the continuous casting process. The k-ɛ turbulence model is used to calculate the turbulent variables. A homogeneous fluid model with variable density is employed to tackle the molten metal-argon gas flow. The electromagnetic force is incorporated into the Navier-Stokes equation, and the effects of boundary conditions of the magnetic field on the velocity distribution near the mold wall are included. A good agreement between the numerically obtained flow-field results and measurements is obtained. The argon gas injection changes the molten metal flow pattern, mainly in the upper portion of the mold. By applying the magnetic field, values of the averaged velocity field in the bulk decrease significantly, and, especially at the top free surface, they become very small, which can cause meniscus freezing. When magnetic-field application and argon gas injection are used together, the external flow field out of the gas plume is significantly suppressed; nevertheless, flotation of gas bubbles is still active and is not affected directly by the magnetic field. Although the penetrating length of the gas plume is shortened, the argon gas bubbles in molten steel still cause fluctuation at the top free surface, which prevents the occurrence of freezing.

Detection and a possible mechanism of magnetic field effect on the crystal growth of sedimentary calcium carbonate

Sedimentary calcium carbonate was grown at a physiological pH6.8 from a mixture of equivolume of 70 mM Ca(NO 3) 2 and 70 mM NaHCO 3 aqueous solution. The kinetics of the crystal growth was monitored by means of turbidity measurement. The apparent absorption is gradually increased with the elapsed time after the mixing and reaches its maximum at t max. The average t max is significantly decreased from 〈 t max〉=467 s (for n=13 runs) to 408 s ( n=13) by application of the static magnetic field (SMF) of H=400 mT to the precipitating solution. The application of SMF at 120 s later the mixing shows the same 〈 t max〉=396 s ( n=9) as that of 408 s. It has been thus detected that the application of SMF is ineffective in the stage of the nucleation or the earlier stage of the crystal growth but effective in the Ostwald ripening stage of the growth nucleus or the later stage of the crystal growth where large numbers of the growing crystalline particles seem greater than a few hundred nanometers. A possible mechanism for the SMF effect is as follows. An ion escaping from the growing crystal surface with a certain ‘migration velocity’ due to a random walk process has significant probability to drift onto the identical surface or at least the identical crystal by means of Lorentz force, because the translational displacement of the crystal during a cycle of the cyclotron motion of the ion is smaller than the size of the growing crystal. This type of drift results in the suppression of re-dissolution of the ions on the growing surface and in the acceleration of the growth in the later stage of the crystal growth. The undetected SMF effect in the earlier stage of the crystal growth can be partly attributed to the re-dissolution due to the thermodynamic instability of the small nuclei which predominates over the presumable SMF effect. This can be partly ascribed to the large translational displacement of the small particle. The application of this mechanism to an oscillating magnetic field will predict the presence of a window for the frequency of the oscillating magnetic field.

The Effect of Static Magnetic Fields on the Photohemolysis of Human Erythrocytes by Ketoprofen

Ultraviolet irradiation (lambda > 300 nm) of the nonsteroidal anti-inflammatory agent ketoprofen (KP, 3-benzoyl-alpha-methylbenzoacetic acid) in aqueous solution, pH 7.4, results in heterolytic decarboxylation of the drug to give 3-ethylbenzophenone (EtBP). Ketoprofen caused the photohemolysis of human erythrocytes probably as a result of lipid peroxidation. Application of a static magnetic field (250-1500 G) during UV (> 300 nm) irradiation of KP and erythrocytes significantly decreased the time required for photohemolysis. This observation suggests that KP-induced photohemolysis involves the initial generation of a triplet radical pair derived from the reaction of triplet state KP (or 3-EtBP) with erythrocyte component(s) probably lipids. The magnetic field increases the concentration and/or lifetime of free radicals that escape from the radical pair so that the critical radical concentration needed to initiate membrane damage and cause cell lysis is reached sooner. Spin-trapping studies with 2,6-dibromo-1-nitrosobenzene-4-sulfonate confirmed that the application of an external static magnetic field increased the concentration of radicals released during the photolysis of either KP or 3-EtBP dissolved in organized media such as sodium dodecylsulfate micelles.

The effect of static magnetic fields on biological systems: Implications for enhanced biodegradation

Numerous studies of the effects of magnetic fields on biological and biochemical systems suggest the potential application of static magnetic fields to enhance microbial degradation of environmental pollutants. Potentially favorable changes in intracellular processes have been observed in controlled studies, including changes in enzymatic activities, growth and respiration rates, increased motility and membrane permeability, and morphological and developmental effects. The provocative thought of combining the emerging areas of biomagnetism and biological treatment is also supported by consideration of existing paradigms of chemistry and physics. Indeed, the few studies that have been conducted recently for this specific purpose show that that enhanced contaminant biodegradation by static magnetic fields is a bona fide phenomenon. Nevertheless, the underlying mechanisms responsible for the effects are not fully understood. The purpose of this article is to stimulate fundamental research leading to a better understanding and a more widespread acceptance of magnetically modified biological treatment processes as an additional tool for pollution control. Emphasis is placed on providing a balanced review of pertinent studies, beginning with a perspective on the nature of magnetic fields used in experimental systems. The effect of static magnetic fields on biological systems at the molecular and cellular levels are then addressed, ending with a discussion of theoretical models proposed to explain the observed effects and a perspective on future research.

Magnetic field enhancement of antibiotic activity in biofilm forming Pseudomonas aeruginosa.

Device related infection initiated by biofilm bacteria are often difficult to resolve with antimicrobial therapy. Study results indicate that application of static magnetic fields may enhance the activity of gentamicin against biofilm forming Pseudomonas aeruginosa adherent to a polymer substrate. Results indicate a maximal reduction of 86.5 +/- 7.2% (n = 6) in the number of adherent viable bacteria compared with a control for samples exposed to a 5 gauss (G) magnetic field and gentamicin. The effect appears to be limited to magnetic fields between 5 and 20 G. Experiments using glass, Chronoflex (Polymedica, Golden, CO), Biomer (Ethicon, Somerville, NJ), and polystyrene substrate showed that the effect was independent of substrate surface. Autoradiograms from In111 uptake experiments showed that bacteria colonizing the substrate surface were significantly reduced in samples subjected to a magnetic field and gentamicin.

Highly reliable cylindrical thin magnetic film memory

Cylindrical thin magnetic film elements for memory application have been extensively studied because they are low cost, undisturbed by external magnetic fields, and have relatively large output. However, continuity of magnetic material on the core conductor surface has made memory properties worse, since a memory region received the effect of adjacent regions by domain wall creepings. This paper will introduce a highly reliable cylindrical thin magnetic film memory, remarkably improved by applying a static magnetic field between the memory areas under neighboring word lines in a memory plane. The direction of the static magnetic field is along the hard axis and opposed to the direction of world fields. The application of static magnetic field results in the improvement of write-in characteristics, the rise in readout signal levels, and the increase in disturb threshold current.