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This work presents the design, construction and validation of a chamber for magnetic field attenuation. The motivation for this work was set by needs of magnetic background controlling during experimental work focused on behavior of biological samples exposed to various level of the low frequency time-varying magnetic field. Thus the solution is proposed with regard to correct cultivation conditions of microbiological samples. The presented proposal benefits from the means of numerical modeling and simulations, as well as 3D printing techniques. The design process incorporates CAD software for the chamber proposal, subsequent print via 3D printer, followed by construction of attenuating chamber using mu-metal foil. Validation was performed via measurements of magnetic flux density with the chamber, which was compared and confirmed via numerical simulations using CST design Studio. All the solution steps resulted in valid and effective magnetic field attenuation chamber, suitable for use in laboratory conditions.
Since the late 1950s, there have been concerns regarding the potential health effects of non ionizing radiation from radar, other radio, and microwave sources. The potential effects of low-intensity fields, such as low-frequency magnetic fields (LF-MF) from the electric power generating, transmission, and distribution system, as well as intermediate, radio-frequency (RF), and higher-frequency radiation from gadgets like cell phones, broadcast antennas, Wi-Fi, security monitors, and so forth, have arisen more recently. These are concerns about the direct effects of exposure on humans or other organisms [1]. Because of the difficulties in establishing the direct biological effects of long-term low-level magnetic fields exposures, the lack of understood mechanisms, and difficulties in obtaining reproducible results are observed. However, there are proposal of a few theories explained the mechanisms of low-level magnetic fields exposures on the field of quantum biology.
Reactive Oxygen Species Theory was proposed by Barnes and Greenebaum [2]. They outlined a model by which changes in radical concentrations may result from exposures to LF-MF, noting that these changes can lead to biologically significant changes in metabolic rates and other processes. Transitions that alter the populations of the combined electron and nuclear states, or F states, can take place at frequencies that correspond to the energy separation between the various states in the external magnetic fields, especially at low external field intensities. This alters the average population of the singlet (S) and triplet (T) states of the electrons in the radical pair. The pair recombination rates change as a result, which can alter radical concentrations and alter biological processes.
Proton-Proton Coupling Theory assume, that a variation in cell parameters due to a resonance in Fibrosarcoma cells could be initiated by coupling the external magnetic field to the nuclear spins of the protons and changing the rate at which proton-to-proton coupling of nuclear spins in a particular configuration changes. This coupling will be strongest at frequencies that correspond to the J (Total electronic angular momentum) value for the frequency equivalent to the energy levels separating the energy difference between the nuclear spins in the two different orientations with the spins parallel or antiparallel. In turn protons in this configuration may be coupled to the active electrons and change the average population density with a quantum number that is coupled to the chemical reaction rates that are controlling the growth rate of Fibrosarcoma cells and signaling molecules such as hydrogen peroxide. The importance of nuclear spins in determining the quantum number of molecules in weak magnetic fields is discussed in various papers [2], [3] and the measured results are consistent with expectations for proton-proton coupling.
In the light of cited theories an experiments with low-level magnetic fields exposures on biological systems require an additional shielding. To access the capability of high permeability metal shielding following the initial phase of the experiment, a numerical simulation is conducted using CST Studio Suite. A simulation of the current setup and improved setup with mu-metal shielding are carried out to evaluate positions within the incubator that are more sensitive to environmental and external fluctuations in the static field. As the outcome of simulations' results an design magnetic field attenuation chamber was proposed. The case of chamber was designed in TinkerCad and printed on high resolution 3D printer and covered with one layer of mu-metal. An additional measurements were performed to verify simulation outcome.
[1] F. Barnes, B. Greenbaum, Some Effects of Weak Magnetic Fields on Biological Systems: RF fields can change radical concentrations and cancer cell growth rates,'' in IEEE Power Electronics Magazine, vol. 20, no. 3(1), 2016, pp. 60--68, ISSN 2329-9207.
[2] F. Barnes, B. Greenbaum,The effects of weak magnetic fields on radical pairs,'' in Bioelectromagnetics, vol. 36, no. 1, 2015, pp. 45--54, ISSN 01978462
[3] L. Buchachenko, E. L. Frankevich, ``Chemical Generation and Reception of Radio and Microwaves,'' Russia, 1994, ISBN: 978-0-471-18859-9
