Influence Of Pulsed Magnetic Field Research Articles

Study on the blood flow in stenosed microvascular model under pulsed magnetic field

It is widely known that abnormal peripheral blood circulation due to intravascular stenosis causes ischemic diseases and blood circulatory disorders. The purpose of this study was to investigate the influence of pulsed magnetic field (PMF) on hemodynamic characteristics in blood vessel with stenosis of 33% with diameter of 15μm, with the change of PMF intensity and hematocrit (Ht) concentration. Stenosed microvascular channels were fabricated using polydimethylsiloxane (PDMS). Our PMF stimulator has the maximum intensity of 2700G at a transition time of 102 μs with pulse intervals of 1Hz. For the Ht altered RBCs suspension, the changes in blood flow and deformation of red blood cells (RBCs) were examined before and after PMF stimulus with various intensity of 200∼2700G. In stenosed channel, threshold intensity for improvement of blood flow seems to be 400G. The higher the Ht, the higher the viscosity and the slower the velocity of RBCs, but after PMF stimulus, RBCs movement overall increased by more than 9∼67% in both Ht 5% and 20% RBCs suspension. Our study shows that PMF plays an important role in in treating cardiovascular diseases with blood circulation disorders caused by narrowing microvascular due to stenosis. In order to extend our results to clinical applications, we need develop more indicators for hemorheologic characteristics such as viscosity and resistance, and need further experiment with diverse PMF condition such as pulse shape, pulse duration, or repetition rate.

ВОЗДЕЙСТВИЕ ИМПУЛЬСНОГО МАГНИТНОГО ПОЛЯ ВЫСОКОЙ НАПРЯЖЕННОСТИ НА ДЕРМАЛЬНЫЕ ФИБРОБЛАСТЫ ЧЕЛОВЕКА В КУЛЬТУРЕ

The influence of pulsed magnetic fields (PMF) with different values of field intensity H, discharge current frequency f and a number of pulses n on dermal fibroblasts was studied in vitro. A specialized pulse-magnetic installation «PMI-Bio» and a measuring stand for creating and monitoring the specified parameters of the PMF were created. Four series of experiments with longitudinal and transverse action of the PMF at a field intensity of 3.76⋅106 – 8.7⋅106 A/m (500 and 1000 J) were carried out. It was found that the longitudinal action of the PMF at 500 J does not lead to cell death, preserves all their structural components, and is safe for primary fibroblast cultures. The use of high-intensity pulsed magnetic fields (HI PMF) at 1000 J in both longitudinal and transverse directions leads to a violation of cell adhesion to the culture plastic and changes in the structure of dermal fibroblasts, up to their death.

Исследование безопасности применения бензилпенициллина натриевой соли после воздействия на нее импульсным магнитным полем

Pulsed magnetic fields are widely used in various fields of modern technology. In our previous works it was shown the strengthening of antibacterial properties of benzylpenicillin sodium salt after exposure to a pulsed magnetic field of high tension. The reason for this may be a change in the conformation of β-lactam antibiotics under external physical influence, which increases the affinity of benzylpenicillin molecules to the active center of penicillin-binding proteins. This article presents studies on the safety of benzylpenicillin sodium salt irradiated by a pulsed magnetic field. Benzylpenicillin sodium salt in powdered form was irradiated with a pulsed magnetic field with the intensity H = (0.09∙106-1.23∙106) A/m, frequency f = 30-70 kHz, and a different number of pulses (n = 1-3), using inductors – single-turn and multi-turn. The influence of pulsed magnetic field on chemiluminescence parameters of irradiated benzylpenicillin sodium salt was studied. The appearance of free radicals in irradiated preparations was evaluated in simple model systems simulating the most common free radical oxidation reactions in the body and in environments in which the formation of reactive oxygen species and lipid peroxidation reactions was initiated. Acute toxicity in intraperitoneal administration of antibiotic to mice before and after treatment with pulsed electromagnetic field with calculation and comparison of LD50 indices was also investigated. It was found that the treatment of the dry substance benzylpenicillin sodium salt by a pulsed magnetic field does not cause the formation of free radicals and is not accompanied by an increase in the toxicity of this antibiotic. The possibility of using new ways to increase the antibacterial activity of antibiotics without increasing their concentrations is considered.

Lethality and mitotic activity of T98G glioblastoma cells under the influence of pulsed magnetic fields and ionizing radiation.

e13511 Background: Development of alternative methods of non-invasive therapy in neurooncology is determined by the need to prevent the continued growth of glioblastoma and radiation-induced complications. Usage of electromagnetic influence for these reasons is determined by the oscillatory nature of intracellular processes and results of previous studies on the effect of weak electromagnetic radiation in tumor growth. The purpose of the study was to reveal the effect of a pulsed magnetic field (PMF) and ionizing radiation (IR) on human T98G glioblastoma cells. Methods: Human T98G glioblastoma cells were cultured in the RPMI-1640 medium (Biolot, Russia) supplemented with 10% fetal bovine serum (Thermo Scientific HyClone, USA). The culture was seeded in the Biofil plates (at least 8x105 cells per 3 mL of the medium), incubated (CB 150 Binder, Germany) and exposed to IR 10 Gy (TheratronEquinox-BestTheratronics) for 11.7 min. and/or PMF 15 mT or 300 mT with a sequence of frequencies 0.3-3.0-9.0 Hz for 7 min. (Neiro-MS/D by Neirosoft, Russia). The efficiency criteria were lethality and the mitotic activity of human T98G glioblastoma cells. Results: The highest cellular lethality was registered 3 hours (18.7 vs. 5.2% in controls, p≤0.05) and a day after IR exposure. PMF 15 or 300 mT alone increased lethality by 2.5-2.8 times compared to controls (p < 0.05). IR plus PMF (15 mT) did not caused increased lethality. At the same time, the most pronounced decrease in the mitotic activity a day after exposure (by 4.7 times, p < 0.05) was registered in PMF alone (15 mT). Conclusions: The inhibitory effect of PMF on the viability of human glioblastoma cells indicates the prospects for its use as an accompanying treatment in neurooncology.

Magnetic Actuator Device Assisted Modulation of Cellular Behavior and Tuning of Drug Release on Silk Platform.

Externally applied physical forces and mechanical stimulations have been found to be instructive to cells which lead to their signaling or differentiation. Further, bioreactors and functional biomaterials have been designed based on this principle to modulate cellular behavior under in vitro conditions. Herein, we have designed a magnetic actuator device (MAD) to understand the fundamental responses of two different phenomena: the effect of actuation on cardiac muscle cells and drug delivery under the influence of pulsed magnetic field. Silk fibroin (SF)-based magnetically responsive matrix, developed by incorporating magnetic iron oxide nanoparticles (IONP) within silk nanofibers was actuated with MAD. The silk matrix was seeded with cells and drugs independently to study effect of physical actuation by MAD on cellular behavior and drug release properties. Neonatal rat cardiomyocytes and H9c2 cells were used for studying the former while model drug was used to observe the latter. Pulsed magnetic stimulation promoted proliferation of cells at a significantly higher rate in comparison to those under static conditions, p ≤ 0.01. For instance, a significantly higher expression of Connexin 43 gene was observed in both H9c2 and primary rat cardiomyocytes under magnetic stimulation compared to nonstimulation conditions after day 14, p ≤ 0.01. A differential drug release profile corresponding to respective actuation frequency was observed while studying drug release properties. Overall, the device can be applied as a non-invasive technique to stimulate cardiac cells grown under laboratory conditions for developing functional artificial construct coupled with additional regulated drug release properties. The study thus demonstrates versatile applications of MAD in biomedical and tissue engineering.

INFLUENCE OF A PULSED MAGNETIC FIELD ON THE ELECTRICAL PROPERTIES OF NANOPOWDER SYSTEM BASED ON ZIRCONIA

A technique for studying of electrical characteristics based on electrochemical impedance spectroscopy of sealed nanopowder compact sets from a powder based on ZrO2 was proposed. The possibility of using this technique for studying of influence of pulsed magnetic field on a charge state of the surface of zirconia nanoparticles is shown. It is established that the action of a weak pulsed magnetic field leads to redistribution of free charge carriers between the volume and the surface of nanoparticles. In particular, different processing times lead to different impedance behaviour: treatment of a pulsed magnetic field with a pulse repetition frequency f = 1 Hz and an exposure time t <15 min leads to an irreversible decrease in the conductivity of the nanoparticle surface by two times (from 3.47 • 10-5 to 1.72 • 10-5 Ohm-1 • m-1), and processing with exposure time 15 <t <90 min leads to its increase by 10 times. Thus, the treatment of PMF causes formation in the near-surface zone of nanoparticles of a region depleted of charge carriers.

Charge and spin current oscillations in a tunnel junction induced by magnetic field pulses

Usually, charge and spin transport properties in tunnel junctions are studied in the DC bias regime and/or in the adiabatic regime of time-varying magnetic fields. In this letter, the temporal dynamics of charge and spin currents in a tunnel junction induced by pulsed magnetic fields is considered. At low bias voltages, energy and momentum of the conduction electrons are nearly conserved in the tunneling process, leading to the description of the junction as a spin-1/2 fermionic system coupled to time-varying magnetic fields. Under the influence of pulsed magnetic fields, charge and spin current can flow across the tunnel junction, displaying oscillatory behavior, even in the absence of DC bias voltage. A type of spin capacitance function, in close analogy to electric capacitance, is predicted.

Estimation of the influence of a pulsed magnetic field on metal surface defects

The influence of pulsed magnetic fields on surface porosity and the roughness of ironand titanium-based alloys is studied. It is shown that a macroscopic approach is unreasonable in calculations of the surface temperature and the related. Efficient calculations should be performed at a nanolevel.

Pulsed magnetic stimulation modifies amplitude of action potentials in vitro via ionic channels-dependent mechanism.

This paper investigates the influence of pulsed magnetic fields (PMFs) on amplitude of evoked, compound action potential (CAP) recorded from the segments of sciatic nerve in vitro. PMFs were applied for 30 min at frequency of 0.16 Hz and intensity of 15 mT. In confirmation of our previous reports, PMF exposure enhanced amplitude of CAPs. The effect persisted beyond PMF activation period. As expected, CAP amplitude was attenuated by antagonists of sodium channel, lidocaine, and tetrodotoxin. Depression of the potential by sodium channels antagonists was reversed by subsequent exposure to PMFs. The effect of elevated potassium concentration and veratridine on the action potential was modified by exposure to PMFs as well. Neither inhibitors of protein kinase C and protein kinase A, nor known free radicals scavengers had any effects on PMF action. Possible mechanisms of PMF action are discussed.

Quantum Phase Transition in HTSC Thick Films: YBa2Cu3O x , YBa2Cu3O x (5 % Ag-Doped) in a Strong Pulsed Magnetic Field up to 32 T at Low Temperatures (58–100 K), Current Densities and Stress-Effect

We have researched the influence of pulsed magnetic fields up to 32 T on the magneto-resistance of thick films (50 Mk) of YBa2Cu3O x and YBa2Cu3O x (5 % Ag-doped) that were produced from synthesized powders. (Figs. 1–9): concentrate with 6.85–6.9 % O2 and a tail fraction 6.5–6.6 % O2.We observed a linear plot at currents of more than 1 mA at 77 K in YBa2Cu3O x (5 % Ag-doped) at B>5 T and in the concentrate YBa2Cu3O x samples with I=1 mA, T=68.2 K. Pulsed magnetic fields up to 32 T, at I=1 mA had practically no influence on the value of the magneto-resistance in the concentrate YBa2Cu3O x specimens at T=57.9 K and up to 17 T for YBa2Cu3O x (5 % Ag) at 77 K (Meissner effect). However, for B>17 T, YBa2Cu3O x (5 % Ag) at 77 K demonstrates a tendency toward lower resistance.In the presence to 10 pulses in a cyclic pulsed magnetic field of 32 T, there is a sharp change of magnetic properties of an HTSC that can lead to nontrivial changes in the transition temperature, due to the strong mechanic stresses, sharp change value structure, and because one of the phases becomes superconducting (Figs. 3A, 3B). The behavior of the magnetoresistance of S-N-S contacts in pulsed magnetic fields is described via the system’s parallel resistance, R n , and the inductance, L S-N-S.Analysis of microscopic models of quantum phase transitions was made in a granular superconductor in an attempt to explain the results on the studied HTSC-films and to give a physical interpretation to the deduced parameters of some experiments on the basis of “spin (vortex) glass” (vortex ice).

Pulsed magnetic field as a new technique to control the crystallization and orientation of poly(trimethylene terephthalate)

Magnetic influence on the crystallization and orientation of poly(trimethylene terephthalate) (PTT) were studied by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), and X-ray diffraction (XRD) during isothermal crystallization at 195 °C under pulsed magnet. The results showed that the crystallization properties of PTT are changed under the influence of pulsed magnetic field. It should be emphasized that the pulsed magnetic field can be applied as a new method to control the crystallization and orientation of polymers.

Influence of pulsed magnetic fields on the morphology of bone cells in early stages of growth

The effect of electromagnetic fields on living systems has been studied both in vivo and in vitro in a wide range of organisms, cells and tissues. However, the mechanism of action of electromagnetic fields is not yet clearly defined. This paper presents the results of applying a pulsed magnetic field of 70 ms width, intensity of 0.65 mT at 4 Hz in human osteoblasts, during 45 min. The magnetic field application was conducted on crops of both 24 and 48 h of proliferation. The effect of applying magnetic fields was assessed using parameters such as cell density, protein content, distribution of F-actin fibrils and β-tubulin and integrity of nuclear structure. The results indicate no alteration in either protein synthesis or nuclear structure, or in the number of cells. However, we observed that exposure to these fields induces changes in the distribution of cytoskeletal proteins of osteoblasts.

Influence of pulsed magnetic field on the bone growth plates in rabbits

Repeated in situ exposure of the rabbit knee joint to a pulsed magnetic field (1.5 T) is shown to suppress the functional activity of bone growth plates.

The influence of pulsed magnetic fields (PMFs) on nonsynaptic potentials recorded from the central and peripheral nervous systems in vitro

The influence of pulsed magnetic fields (PMFs) on nonsynaptic potentials recorded from the central and peripheral nervous system in vitro has been investigated. The population spikes (PSs) recorded from hippocampal slices during antidromic stimulation and compound action potentials (CAPs) recorded from the segments of the sciatic nerve were used as indicators of neuronal activity. The potentials recorded from both preparations were significantly and permanently enhanced following PMF (0.16 Hz, 15 mT) exposure. The increase in the antidromic PS occurred even in the presence of potassium channel blocker tetraethylammonium (TEA) and was accompanied by multiple spiking. Among all frequencies of PMF tested (0.5, 0.16, 0.07, 0.03, 0.0 Hz), the frequency of 0.5 Hz was the most effective in enhancement of potential amplitude. The influence of PMF on the amplitude of two CAPs evoked by the pair of electrical stimuli applied in rapid succession has also been evaluated. In control conditions the potential triggered by the second stimuli was slightly smaller expressing the phenomenon of short-term depression (STD). Although PMF exposure amplified the amplitude of both potentials, the increase in the size of the first potential was significantly greater increasing further the magnitude of STD. The blocking of potassium channels reversed STD into facilitation. One of the possible mechanisms involved in PMF action could be the modification of the axonal threshold, which was significantly reduced following exposure to PMF.

Investigation of Magneto-Resistance Behavior in High Pulsed Magnetic Fields up to 35 T of YBa2Cu3O x and YBa2Cu3O x (5% Ag-doped) Thick Films Near 77 K

We investigated the influence of pulsed magnetic fields of up to 35 T on thick film samples of YBa2Cu3Ox (x<6.8) and YBa2Cu3Ox (5% Ag-doped), produced from powders on which electromagnetic separation had been performed. It was discovered, that subjecting the thick film samples of YBa2Cu3Ox to 10 pulses of a cyclic pulsed magnetic field of 32 T had the effect of significantly increasing Tc. The films had an oxygen deficit of 6.6–6.8%. Initially, Tc was 74 K. After the treatments by the strong pulses of magnetic fields, Tc had increased to 80 K. On the other hand, in YBa2Cu3Ox (5% Ag), the processing by strong pulsed magnetic fields will lead to dynamic mechanic stresses, which will increase the amount of tetragonal phases and lead to a lower temperature of the superconductivity transition.

Neurophysiological Effects Induced in the Nervous Tissue by Low-Frequency, Pulsed Magnetic Fields

The influence of pulsed magnetic fields (PMF) on the properties of nervous tissue was investigated. Hippocampal slices or synaptosomes obtained from hippocampal tissue were used as model systems. The amplitude of potentials recorded in vitro from one of the hippocampal pathways (Schaffer collaterals that use glutamate as a neurotransmitter) was employed as a measure of the influence of magnetic fields on synaptic efficiency. The synaptic glutamate turnover and radioactive calcium accumulation were used as markers of the PMF influence on biochemistry of synaptic mechanisms. The exposure of hippocampal slices for 30 min to PMF amplified evoked potentials. While the frequency of 0.16 Hz exerted the strongest effect, lower (0.01, 0.07, 0.03 Hz) and higher (0.5 Hz) frequencies were much less effective. The enhancement of the neuronal excitability was correlated with significant increase in the neuronal spontaneous activity mediated by electrical synapses. The PMF-induced changes in the excitability of the tissue were accompanied by an increase in the synaptic turnover of glutamate. The release of radioactive D-Aspartate (a glutamate analog used as a marker for glutamate turnover) from the slices, and its uptake by synaptosomes were enhanced, and reduced respectively, following the stimulation with pulsed magnetic fields. The frequency which was the most efficient in amplification of evoked potentials (0.16 Hz) was also the most effective in the modulation of the release and uptake processes. The PMF-induced changes in neurotransmitter turnover coincided with an increase in 45Ca2+ accumulation observed in hippocampal slices exposed to PMF.

Modification of the synaptic glutamate turnover in the hippocampal tissue exposed to low-frequency, pulsed magnetic fields

The influence of pulsed magnetic fields (PMF) on the release and uptake of glutamate was investigated. While the release was examined using hippocampal slices, synaptosomes were chosen to characterize the uptake process. 3 H- d-aspartate was used as a marker of glutamergic transmission. The pulsed magnetic fields (9–15 mT) applied according to the pattern which induced epileptic discharges in hippocampus amplified and attenuated the release and uptake of glutamate, respectively. However, the magnetic fields which induced an increase in neuronal excitability without concomitant seizures amplified both processes. These results confirm our previous reports and indicate that the glutamergic synapses are the target of magnetic fields action.

Theory of domain wall dynamics in bubble films with coercivity

We propose a simple, obvious model for coercivity, that is in agreement with the experimental data. The problem of domain wall (DW) displacement under the influence of pulsed magnetic field is solved for the general case, when both the pulse amplitudes and durations are different. The cases of infinitesimally small and finite pulse front durations are considered. It is shown that the character of the DW dynamics character is defined by the sign of the parameter λ 2=( β m ) 2− 4k m , where m is the mass of the DW, and β and k are viscous friction and stiffness coefficients, respectively. In the chosen model the remaining shift of the DW (the difference between the DW coordinates after the influence of two equal and oppositely directed magnetic field pulses) is connected only with the coercivity. In the demonstrated procedure, every reasonable form of both magnetic and coercive fields may be used.

Influence of pulsed magnetic fields caused by plasma current disruption on tokamak TF superconducting coils operation

Impact of pulsed magnetic field caused by plasma current disruption in fusion tokamak devices on TF superconducting coil (TFSC) operation was considered. Superconducting wire (SW) heating level dependence on TFSC design parameters and various forced cooling modes was defined.

Characteristics of the stimulated emission from iodine atoms in pulsed magnetic fields

An investigation was made of the influence of pulsed magnetic fields on the characteristics of the stimulated radiation resulting from the 2P1/2–2P3/2 transition in iodine atoms. It was found that pulsed magnetic fields could be used to modulate the gain and the output power of this iodine laser.