Biological cell as a soft magnetoelectric material: Elucidating the physical mechanisms underpinning the detection of magnetic fields by animals

On the origin of the biological effects of time varying magnetic fields: quantitative insights

In a number of recently published experimental studies from our research group, the positive impact of magnetic stimuli (static/pulsed) on cell functionality modulation or bactericidal effects, in vitro, has been established. In order to develop a theoretical understanding of such magnetobiological effects, the present study aimed to present two quantitative models to determine magnetic Maxwell stresses as well as pressure acting on the cell membrane, under the influence of a time varying magnetic field. The model predicts that magnetic field-induced stress on the cell/bacteria is dependent on the conductivity properties of the extracellular region, which is determined to be too low to cause any significant effect. However, the force on the cell/bacteria due to the induced electric field is more influential than that of the magnetic field, which has been used to determine the membrane tension that can cause membrane poration. With a known critical membrane tension for cells, the field parameters necessary to cause membrane rupture have been estimated. Based on the experimental results and theoretically predicted values, the field parameters can be classified into three regimes, wherein the magnetic fields cause no effect or result in biophysical stimulation or induce cell death due to membrane damage. Taken together, this work provides some quantitative insights into the impact of magnetic fields on biological systems.

Numerical tests of magnetoreception models assisted with behavioral experiments on American cockroaches

Many animals display sensitivity to external magnetic field, but it is only in the simplest organisms that the sensing mechanism is understood. Here we report on behavioural experiments where American cockroaches (Periplaneta americana) were subjected to periodically rotated external magnetic fields with a period of 10 min. The insects show increased activity when placed in a periodically rotated Earth-strength field, whereas this effect is diminished in a twelve times stronger periodically rotated field. We analyse established models of magnetoreception, the magnetite model and the radical pair model, in light of this adaptation result. A broad class of magnetite models, based on single-domain particles found in insects and assumption that better alignment of magnetic grains towards the external field yields better sensing and higher insect activity, is shown to be excluded by the measured data. The radical-pair model explains the data if we assume that contrast in the chemical yield on the order of one in a thousand is perceivable by the animal, and that there also exists a threshold value for detection, attained in an Earth-strength field but not in the stronger field.

The different sources of electromagnetic fields: Dangers are not limited to physical health

The impact of electromagnetic waves on health has been clearly established by many studies in recent decades. No State, with the exception of Russia, takes any real precautions in terms of standards for the population. Conflicts of interest and political lies are used to hide the truth about the dangers of electromagnetic pollution.In addition, it would seem that other sources of radiation than the most well-known ones (mobile phones, digital enhanced cordless telecommunication (DECT) phones, bluetooth, base stations, Wi-Fi, 4G, 5G) come into play. A system such as HAARP (High-frequency Active Auroral Research Program), as well as directed wave beams (related to past and recent scandals) must be analyzed and considered in a comprehensive way to understand why the wave level is only increasing despite the considerable amount of scientific work demonstrating that the standards are not adequate to maintain public health.Thus, official documents show that the impact of electromagnetic waves is not only physical and biological. Indeed, the climate and the behavior of the population are also targeted.

Analytical estimation of non-local deformation-mediated magneto-electric coupling in soft composites

For a long time, the search for magneto-electric materials concentrated on multi-ferroics and hard-matter composites. By contrast, rather recently the exploitation of strain-mediated magneto-electric (ME) coupling in soft composites was proposed. The basic idea behind this approach is to combine the magneto- and electro-mechanical responses of composites consisting of a soft matrix carrying magnetic inclusions. Despite that such composites are straightforward to manufacture and have cheap constituents, they did not gain much attention up to now. In this contribution, we demonstrate that ME coupling induced by finite deformations could be of significant magnitude. Our approach relies on shape effects as a special non-local phenomenon in magneto- and electro-elasticity. Based on that we characterize an up to now overlooked ME coupling mechanism which purely relies on these shape effects in soft-matter-based magnetic and electric media. While soft magnetic media are commonly realized as composites, the coupling effect to be highlighted exists independently of the origin of a body's magnetic and electric properties. We show that the magnitude of the effect is indeed significant and, among ellipsoidal bodies, most pronounced for those of spherical to moderately prolate shape. Finite-element simulations are performed to assess the quality of the analytical predictions.

Emergent magnetoelectricity in soft materials, instability, and wireless energy harvesting

Magnetoelectric materials that convert magnetic fields into electricity and vice versa are rare and usually complex, hard crystalline alloys. Recent work has shown that soft, highly deformable magnetoelectric materials may be created by using a strain-mediated mechanism. The electromagnetic and elastic deformation of such materials is intricately coupled, giving rise to a rather rich instability and bifurcation behavior that may limit or otherwise put bounds on the emergent magnetoelectric behavior. In this work, we investigate the magneto-electro-mechanical instability of a soft dielectric film subject to mechanical forces and external electric and magnetic fields. We explore the interplay between mechanical strain, electric voltage and magnetic fields and their impact on the maximum voltage and the stretch the dielectric material can reach. Specifically, we present physical insights to support the prospects to achieve wireless energy harvesting through remotely applied magnetic fields.