Linked Life Data

11783873

Source:http://linkedlifedata.com/resource/pubmed/id/11783873

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2002-1-9
pubmed:abstractText
Several organizations worldwide have issued guidelines to limit occupational and public exposure to electric and magnetic fields and contact currents in the extremely low frequency range (<3 kilohertz). In this paper, we evaluate relevant developments in biological and health research, computational methods for estimating dosimetric quantities, and exposure assessment, all with an emphasis on the power frequency (60 hertz in North America, 50 hertz in Europe). The aim of each guideline is to prevent acute neural effects of induced electric fields. An evaluation of epidemiological and laboratory studies of neurobiological effects identified peripheral nerve stimulation as the response most suitable for establishing a magnetic-field guideline. Key endpoints that merit further study include reversal of evoked potentials; cardiovascular function, as measured by heart rate and heart rate variability; and sleep patterns. High-resolution computations of induced electric fields and current densities in anatomically correct human models are now achieved with finite-difference methods. The validity and limitations of these models have been demonstrated by computations in regular geometric shapes, using both analytic and numeric computations. Calculated values for average dosimetric quantities are typically within a few percent for the two approaches. However, maximum induced quantities are considerably overestimated by numerical methods, particularly at air interfaces. Overestimates are less pronounced for the upper 99th percentile level of a dosimetric quantity, making this measure a more useful indicator of maximum dose. Neural stimulation thresholds are dependent on the electric field around the excitable cell rather than on the current density, making the former preferable for expression of basic restrictions based on nervous system function. Furthermore, modeling data indicate that the induced electric field is much less strongly influenced by tissue conductivity than is the induced current density. In the electric utility industry, most magnetic-field exposures at or near guideline levels occur in highly nonuniform fields. Two methods are described for simplified estimation of induced quantities in such fields, with each method using as input modeling results for uniform field exposure. These methods have practical value for assessing occupational exposures relative to guideline levels.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1047-322X
pubmed:author
pubmed:issnType
Print
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1118-38
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Evaluation of biological effects, dosimetric models, and exposure assessment related to ELF electric- and magnetic-field guidelines.
pubmed:affiliation
EPRI, Palo Alto, California, USA.
pubmed:publicationType
Journal Article, Review