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Research in Veterinary Science Aug 2018Pulsed electromagnetic field (PEMF) therapy can non-invasively treat a variety of pathologies by delivering electric and magnetic fields to tissues via inductive coils.... (Review)
Review
Pulsed electromagnetic field (PEMF) therapy can non-invasively treat a variety of pathologies by delivering electric and magnetic fields to tissues via inductive coils. The electromagnetic fields generated by these devices have been found to affect a variety of biological processes and basic science understanding of the underlying mechanisms of action of PEMF treatment has accelerated in the last 10 years. Accumulating clinical evidence supports the use of PEMF therapy in both animals and humans for specific clinical indications including bone healing, wound healing, osteoarthritis and inflammation, and treatment of post-operative pain and edema. While there is some confusion about PEMF as a clinical treatment modality, it is increasingly being prescribed by veterinarians. In an effort to unravel the confusion surrounding PEMF devices, this article reviews important PEMF history, device taxonomy, mechanisms of action, basic science and clinical evidence, and relevant trends in veterinary medicine. The data reviewed underscore the usefulness of PEMF treatment as a safe, non-invasive treatment modality that has the potential to become an important stand-alone or adjunctive treatment modality in veterinary care.
Topics: Animals; Electromagnetic Fields; Humans; Magnetic Field Therapy; Wound Healing
PubMed: 29775839
DOI: 10.1016/j.rvsc.2018.05.005 -
Acta Otorhinolaryngologica Italica :... Oct 2023
Topics: Humans; Nystagmus, Pathologic; Vertigo; Magnetic Fields
PubMed: 37519140
DOI: 10.14639/0392-100X-N2485 -
IEEE Transactions on Bio-medical... Feb 2022Optically pumped magnetometers (OPMs) have made moving, wearable magnetoencephalography (MEG) possible. The OPMs typically used for MEG require a low background magnetic...
BACKGROUND
Optically pumped magnetometers (OPMs) have made moving, wearable magnetoencephalography (MEG) possible. The OPMs typically used for MEG require a low background magnetic field to operate, which is achieved using both passive and active magnetic shielding. However, the background magnetic field is never truly zero Tesla, and so the field at each of the OPMs changes as the participant moves. This leads to position and orientation dependent changes in the measurements, which manifest as low frequency artefacts in MEG data.
OBJECTIVE
We model the spatial variation in the magnetic field and use the model to predict the movement artefact found in a dataset.
METHODS
We demonstrate a method for modelling this field with a triaxial magnetometer, then show that we can use the same technique to predict the movement artefact in a real OPM-based MEG (OP-MEG) dataset.
RESULTS
Using an 86-channel OP-MEG system, we found that this modelling method maximally reduced the power spectral density of the data by 27.8 ± 0.6 dB at 0 Hz, when applied over 5 s non-overlapping windows.
CONCLUSION
The magnetic field inside our state-of-the art magnetically shielded room can be well described by low-order spherical harmonic functions. We achieved a large reduction in movement noise when we applied this model to OP-MEG data.
SIGNIFICANCE
Real-time implementation of this method could reduce passive shielding requirements for OP-MEG recording and allow the measurement of low-frequency brain activity during natural participant movement.
Topics: Artifacts; Brain; Humans; Magnetic Fields; Magnetoencephalography
PubMed: 34324421
DOI: 10.1109/TBME.2021.3100770 -
Scientific Reports Jan 2023The rate of a chemical reaction can be sensitive to the isotope composition of the reactants, which provides also for the sensitivity of such "spin-sensitive" reactions...
The rate of a chemical reaction can be sensitive to the isotope composition of the reactants, which provides also for the sensitivity of such "spin-sensitive" reactions to the external magnetic field. Here we demonstrate the effect of the external magnetic field on the enzymatic DNA synthesis together with the effect of the spin-bearing magnesium ions ([Formula: see text]Mg). The rate of DNA synthesis monotonously decreased with the external magnetic field induction increasing in presence of zero-spin magnesium ions ([Formula: see text]Mg). On the contrary, in the presence of the spin-bearing magnesium ions, the dependence of the reaction rate on the magnetic field induction was non-monotonous and possess a distinct minimum at 80-100 mT. To describe the observed effect, we suggested a chemical scheme and biophysical mechanism considering a competition between Zeeman and Fermi interactions in the external magnetic field.
Topics: Magnesium; DNA Replication; Biophysics; Magnetic Fields; Protein Biosynthesis
PubMed: 36627313
DOI: 10.1038/s41598-022-26744-4 -
Sensors (Basel, Switzerland) Apr 2023Biomagnetism is the measurement of the weak magnetic fields produced by nerves and muscle. The magnetic field of the heart-the magnetocardiogram (MCG)-is the largest... (Review)
Review
Biomagnetism is the measurement of the weak magnetic fields produced by nerves and muscle. The magnetic field of the heart-the magnetocardiogram (MCG)-is the largest biomagnetic signal generated by the body and was the first measured. Magnetic fields have been detected from isolated tissue, such as a peripheral nerve or cardiac muscle, and these studies have provided insights into the fundamental properties of biomagnetism. The magnetic field of the brain-the magnetoencephalogram (MEG)-has generated much interest and has potential clinical applications to epilepsy, migraine, and psychiatric disorders. The biomagnetic inverse problem, calculating the electrical sources inside the brain from magnetic field recordings made outside the head, is difficult, but several techniques have been introduced to solve it. Traditionally, biomagnetic fields are recorded using superconducting quantum interference device (SQUID) magnetometers, but recently, new sensors have been developed that allow magnetic measurements without the cryogenic technology required for SQUIDs.
Topics: Humans; Heart; Magnetoencephalography; Brain; Magnetic Fields; Myocardium
PubMed: 37177427
DOI: 10.3390/s23094218 -
Journal of Comparative Physiology. A,... Jan 2022In addition to providing animals with a source of directional or 'compass' information, Earth's magnetic field also provides a potential source of positional or 'map'... (Review)
Review
In addition to providing animals with a source of directional or 'compass' information, Earth's magnetic field also provides a potential source of positional or 'map' information that animals might exploit to assess location. In less than a generation, the idea that animals use Earth's magnetic field as a kind of map has gone from a contentious hypothesis to a well-established tenet of animal navigation. Diverse animals ranging from lobsters to birds are now known to use magnetic positional information for a variety of purposes, including staying on track along migratory pathways, adjusting food intake at appropriate points in a migration, remaining within a suitable oceanic region, and navigating toward specific goals. Recent findings also indicate that sea turtles, salmon, and at least some birds imprint on the magnetic field of their natal area when young and use this information to facilitate return as adults, a process that may underlie long-distance natal homing (a.k.a. natal philopatry) in many species. Despite recent progress, much remains to be learned about the organization of magnetic maps, how they develop, and how animals use them in navigation.
Topics: Animal Migration; Animals; Birds; Magnetic Fields; Magnetics; Turtles
PubMed: 34999936
DOI: 10.1007/s00359-021-01529-8 -
Occupational Medicine (Oxford, England) Apr 2022Many studies have investigated magnetic field exposure and the risks of motor neuron disease (MND). Meta-analyses have found positive associations but a causal...
BACKGROUND
Many studies have investigated magnetic field exposure and the risks of motor neuron disease (MND). Meta-analyses have found positive associations but a causal relationship has not been established.
AIMS
To investigate the risks of MND and occupational exposure to magnetic fields in a large UK cohort.
METHODS
Mortality of 37 986 employees of the former Central Electricity Generating Board of England and Wales was investigated for the period 1987-2018. Employees were first employed in the period 1942-82 and were still in employment on the 1 November, 1987. Detailed calculations enabled estimates to be made of magnetic field exposures. Observed deaths were compared with expected numbers based on mortality rates for the general population of England and Wales and Poisson regression was used to calculate rate ratios (relative risks) for categories of lifetime, lagged (distant) and lugged (recent) magnetic field exposure.
RESULTS
Mortality from MND in the total cohort was similar to national rates (observed 69, expected 71.3, SMR 97, 95% CI 76-122). There were no statistically significant trends of risks increasing with lifetime, recent or distant magnetic field exposure, although positive associations were observed for some categories of recent exposure.
CONCLUSIONS
The study did not find that the cohort had elevated risks of MND as a consequence of occupational lifetime exposure to magnetic fields, although a possible role for recent exposures could usefully be investigated in other datasets.
Topics: Cohort Studies; Humans; Magnetic Fields; Motor Neuron Disease; Occupational Diseases; Occupational Exposure
PubMed: 34940878
DOI: 10.1093/occmed/kqab180 -
Sensors (Basel, Switzerland) Jul 2022In recent years, the usage of radio frequency magnetic fields for biomedical applications has increased exponentially. Several diagnostic and therapeutic methodologies... (Review)
Review
In recent years, the usage of radio frequency magnetic fields for biomedical applications has increased exponentially. Several diagnostic and therapeutic methodologies exploit this physical entity such as, for instance, magnetic resonance imaging, hyperthermia with magnetic nanoparticles and transcranial magnetic stimulation. Within this framework, the magnetic field focusing and shaping, at different depths inside the tissue, emerges as one of the most important challenges from a technological point of view, since it is highly desirable for improving the effectiveness of clinical methodologies. In this review paper, we will first report some of the biomedical practices employing radio frequency magnetic fields, that appear most promising in clinical settings, explaining the underneath physical principles and operative procedures. Specifically, we direct the interest toward hyperthermia with magnetic nanoparticles and transcranial magnetic stimulation, together with a brief mention of magnetic resonance imaging. Additionally, we deeply review the technological solutions that have appeared so far in the literature to shape and control the radio frequency magnetic field distribution within biological tissues, highlighting human applications. In particular, volume and surface coils, together with the recent raise of metamaterials and metasurfaces will be reported. The present review manuscript can be useful to fill the actual gap in the literature and to serve as a guide for the physicians and engineers working in these fields.
Topics: Human Body; Humans; Hyperthermia, Induced; Magnetic Fields; Magnetic Resonance Imaging; Radio Waves
PubMed: 35890812
DOI: 10.3390/s22145132 -
Molecules (Basel, Switzerland) Jun 2022Magnetic composites and self-healing materials have been drawing much attention in their respective fields of application. Magnetic fillers enable changes in the... (Review)
Review
Magnetic composites and self-healing materials have been drawing much attention in their respective fields of application. Magnetic fillers enable changes in the material properties of objects, in the shapes and structures of objects, and ultimately in the motion and actuation of objects in response to the application of an external field. Self-healing materials possess the ability to repair incurred damage and consequently recover the functional properties during healing. The combination of these two unique features results in important advances in both fields. First, the self-healing ability enables the recovery of the magnetic properties of magnetic composites and structures to extend their service lifetimes in applications such as robotics and biomedicine. Second, magnetic (nano)particles offer many opportunities to improve the healing performance of the resulting self-healing magnetic composites. Magnetic fillers are used for the remote activation of thermal healing through inductive heating and for the closure of large damage by applying an alternating or constant external magnetic field, respectively. Furthermore, hard magnetic particles can be used to permanently magnetize self-healing composites to autonomously re-join severed parts. This paper reviews the synthesis, processing and manufacturing of magnetic self-healing composites for applications in health, robotic actuation, flexible electronics, and many more.
Topics: Magnetic Fields; Magnetics; Robotics
PubMed: 35744920
DOI: 10.3390/molecules27123796 -
Annual Review of Neuroscience Jul 2019Magnetic fields pass through tissue undiminished and without producing harmful effects, motivating their use as a wireless, minimally invasive means to control neural... (Review)
Review
Magnetic fields pass through tissue undiminished and without producing harmful effects, motivating their use as a wireless, minimally invasive means to control neural activity. Here, we review mechanisms and techniques coupling magnetic fields to changes in electrochemical potentials across neuronal membranes. Biological magnetoreception, although incompletely understood, is discussed as a potential source of inspiration. The emergence of magnetic properties in materials is reviewed to clarify the distinction between biomolecules containing transition metals and ferrite nanoparticles that exhibit significant net moments. We describe recent developments in the use of magnetic nanomaterials as transducers converting magnetic stimuli to forms readily perceived by neurons and discuss opportunities for multiplexed and bidirectional control as well as the challenges posed by delivery to the brain. The variety of magnetic field conditions and mechanisms by which they can be coupled to neuronal signaling cascades highlights the desirability of continued interchange between magnetism physics and neurobiology.
Topics: Animals; Anxiety; Behavior, Animal; Brain; Humans; Magnetic Fields; Nerve Net; Neurons
PubMed: 30939100
DOI: 10.1146/annurev-neuro-070918-050241