This manuscript is divided in two parts. The extensive survey in biological incubators presented in PART I reveals how the background magnetic field can vary by orders of magnitude within and between incubators. These variations can be observed within the same incubator in locations that are centimeters apart from each other as well as between incubators that are identical and located in the same laboratory. Additionally, the values measured were frequently outside of the range of magnitudes found naturally on Earth's surface or ordinary habitation spaces. Exposure to such altered environments has been shown experimentally to be sufficient to cause numerous effects in cell cultures. Examples of the effects reported span from differential generation of free radicals and heat shock proteins to differences in cellular proliferation, differentiation and death. Although the effects are not well established and the molecular mechanism of action is currently under debate, these observations alone support the notion that the inhomogeneity of the background magnetic field in biological incubators is a potential confounding source of the variability and irreproducibility for studies performed on cell cultures. More specifically, the existence of this uncontrolled factor would be especially counterproductive when investigating the biological effects of exposure to magnetic fields of comparable characteristics as the ones measured in this study or when studying small biological effects in general. PART II utilizes the set of measurements obtained in PART 1 to study the possibility of engineering a practical solution to ameliorate this problem. This maturates into a fully characterized prototype which provides a controlled background electric, magnetic and electromagnetic environment for cell or microbiological culture upon being placed inside a standard biological incubator. The design, in part, consists of a novel high permeability shield architecture which does not include doors or lids which was found to be comparable to "lidded" designs used extensively in preceding Bioelectromagnetics research. Its performance was verified by simulating the residual magnetic fields in its interior after being inserted into the 21 incubators surveyed in PART 1. The device's thermal characteristics and the tools and methods implemented to test this design are also fully characterized.
|Advisor:||Barnes, Frank S.|
|Commitee:||Ferguson, Virginia, Filipovic, Dejan, Hernandez, Mark, Su, Tin Tin|
|School:||University of Colorado at Boulder|
|School Location:||United States -- Colorado|
|Source:||DAI-B 74/05(E), Dissertation Abstracts International|
|Subjects:||Biomedical engineering, Electrical engineering, Electromagnetics|
|Keywords:||Ambient mangnetic fields, Biological incubators, Hypogeomagnetics, Magnetic shields, Power frequency fields|
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