Browsing by Author "Toivo, Tim"
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- ItemEpidemiological risk assessment of mobile phones and cancer: where can we improve?(2006-11-19) Auvinen, Anssi; Toivo, Tim; Tokola, KariThis paper aims to provide an overview of factors affecting the validity of epidemiological studies on health effects of mobile phone use A qualitative review of published studies is presented covering both risk assessment and exposure assessment Considerable random error is likely to have occurred in studies carried out so far primarily related to exposure assessment Self reported use of mobile phone appears to be imprecise The relationship between the amount of mobile phone use and the radio frequency field is unclear Several factors affect the strength of the radio frequency field emitted by the phone and accommodating their effect has the potential to improve exposure assessment The major opportunity to improve the quality of evidence is however through prospective studies The major limitation of epidemiological studies addressing the health effects of mobile phone use is related to exposure assessment These limitations are inherent in case control studies Quality of evidence can be improved by conducting prospective cohort studies
- ItemIn vitro effect of pulsed 900 MHz GSM radiation on mitochondrial membrane potential and motility of human spermatozoa.(2008-04-10) Falzone, Nadia; Huyser, Carin; Fourie, Francois; Toivo, Tim; Leszczynski, Dariusz; Franken, DanielEjaculated density purified human spermatozoa were exposed to pulsed 900 MHz GSM mobile phone radiation at two specific absorption rate levels SAR 2 0 and 5 7 W kg and compared with controls over time Change in sperm mitochondrial membrane potential was analysed using flow cytometry Sperm motility was determined by computer assisted sperm analysis CASA There was no effect of pulsed 900 MHz GSM radiation on mitochondrial membrane potential This was also the case for all kinematic parameters assessed at a SAR of 2 0 W kg However over time the two kinematic parameters straight line velocity VSL and beat cross frequency BCF were significantly impaired P Under 0 05 after the exposure at SAR 5 7 W kg and no exposure by time interaction was present This result should not be ascribed to thermal effects due to the cooling methods employed in the RF chamber and temperature control within the incubator
- ItemNo effects of mobile phone electromagnetic field on auditory brainstem response.(2009-12-22) Kwon, Myoung-Soo; Jääskeläinen, Satu K; Toivo, Tim; Hämäläinen, HeikkiThe present study investigated the possible effects of the electromagnetic field EMF emitted by an ordinary GSM mobile phone 902 4 MHz pulsed at 217 Hz on brainstem auditory processing Auditory brainstem responses ABR were recorded in 17 healthy young adults without a mobile phone at baseline and then with a mobile phone on the ear under EMF off and EMF on conditions The amplitudes latencies and interwave intervals of the main ABR components waves I III V were compared among the three conditions ABR waveforms showed no significant differences due to exposure suggesting that short term exposure to mobile phone EMF did not affect the transmission of sensory stimuli from the cochlea up to the midbrain along the auditory nerve and brainstem auditory pathways
- ItemSpecific absorption rate and electric field measurements in the near field of six mobile phone base station antennas.(2009-04-08) Toivonen, Tommi; Toivo, Tim; Puranen, Lauri; Jokela, KariIn this article the exposure to radio frequency electromagnetic fields was studied in close proximity distances of 10 100 300 and 600 mm to six base station antennas The specific absorption rate SAR in 800 mm x 500 mm x 200 mm box phantom as well as unperturbed electric field E in air was measured The results were used to determine whether the measurement of local maximum of unperturbed electric field can be used as a compliance check for local exposure Also the conservativeness of this assessment method compared to the ICNIRP basic restriction was studied Moreover the assessment of whole body exposure was discussed and the distance ranges presented in which the ICNIRP limit for local exposure could be exceeded before the limit for whole body SAR These results show that the electric field measurement alone can be used for easy compliance check for the local exposure at all distances and for all antenna types studied However in some cases when the local peak value of E was compared directly to the ICNIRP reference level for unperturbed E the exposure was overestimated only very slightly by factor 1 1 compared to the basic restriction for localized SAR in a human and hence these results can not be generalized to all antenna types Moreover it was shown that the limit for localized exposure could be exceeded before the limit for the whole body average SAR if the distance to the antenna was less than 240 mm