{'fraction_non_alphanumeric': 0.023184868822452714, 'fraction_numerical': 0.010372178157413058, 'mean_word_length': 4.752631578947368, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Health aspects of wireless communication: cellular telephones and their effect on the human brain

Recently, there have been several print and broadcast media coverages of epidemiological studies from Sweden and the U.S. that focus on cell or mobile telephone use and brain tumors. They were referred to as Hardell and Muscat studies, respectively. Both studies are yet to he published. Also, neither study showed any overall increase in brain tumors, as compared to nonusers. However, there appeared to be a tendency toward greater likelihood (statistically not significant) to develop brain tumors on the side of the head where the phone is held. Researchers of the two studies have stated that their results were based on small numbers of cases, and must be interpreted with caution. Preliminary indications were that their cases and controls ranged from 200 to 500. The results would be more reliable if the numbers are circa 1500 in these studies. It is possible that the numbers would be greater by the time the studies are ready for publication. These reports of unpublished results must be considered as preliminary observations at this moment. It is well to recall that the use of cellular telephones by the general population is a very recent event. Given the long latency of brain tumor development, a large increase in brain tumors over the short term would be a rare and unsettling phenomenon to behold. Moreover, epidemiological studies using small sample sizes are not always reliable. For example, a limited study of cancer incidences near the Sutton-Coldfield radio and TV towers in the U.K. indicated an increase in relative risk (1.83 from 1.00) of adult leukemia within 2 km. And there was a significant decline in risk in proportion with distance away from the towers for leukemia, and for bladder and skin cancers [1]. A follow-up study of 20 other broadcast sites in U.K. found an excess risk no more than 15% at any distance up to 10 km, and there was no observed excess within 2 km [2]. The authors of these Sutton-Coldfield studies suggested after the enlarged study that no more than a weak causal implication can be made. A recent publication in the International Journal of Radiation Biology by Preece et al. [3], suggested that exposure to RF radiation from simulated mobile telephone transmissions at 915 MHz may affect cognitive function in humans. In particular, the choice reaction time of 36 subjects, in randomized laboratory test sessions, showed a RF power-dependent increase in speed (a decrease in reaction time of 15 ms). There were no changes in short-term memory. At the time of its publication, the report touched off a flurry of news stories also. (Unfortunately, some media reports had erroneously alluded to RF exposure from cell phones affects memory, which has contributed to the controversy.) Like other new findings, the implication of this laboratory study must await further scientific confirmation. Nevertheless, the conduction velocity of nerve impulses is known to rise, or fall in the case of conduction latency, with small increases in temperature. Changes in evoked responses of the central nervous system in vivo and spontaneous firing patterns of isolated neurons in vitro have been observed for temperature increases