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van Asselen, B., Schwarz, M., van Vliet-Vroegindeweij, C., Lebesque, J. V., Mijnheer, B. J., & Damen, E. M. F. (2006). Intensity-modulated radiotherapy of breast cancer using direct aperture optimization. Radiother Oncol, 79(2), 162–169.
Abstract: BACKGROUND AND PURPOSE: To design a clinically reliable and efficient step-and-shoot IMRT delivery technique for the treatment of breast cancer using direct aperture optimization (DAO). Using DAO, segments are created and optimized within the same optimization process. PATIENTS AND METHODS: The DAO technique implemented in the Pinnacle treatment planning system, which is called direct machine parameter optimization (DMPO), was used to generate IMRT plans for twelve breast cancer patients. The prescribed dose was 50 Gy. Two DMPO plans were generated. The first approach uses DMPO only; the second technique combines DMPO with two predefined segments (DMPO(segm)), having shapes identical to the conventional tangential fields. The weight of these predefined segments is optimized simultaneously with DMPO. The DMPO plans were compared with normal two-step (TS) IMRT, creating segments after optimizing the intensity. RESULTS: Dose homogeneity within the target volume was 4.8+/-0.6, 4.3+/-0.5 and 3.8+/-0.5 Gy for the TS, DMPO and DMPO(segm) plans, respectively. Comparing the IMRT plans with an idealized dose distribution obtained using only beamlet optimization, the degradation of the dose distribution was less for the DMPO plans compared with the two-step IMRT approach. Furthermore, this degradation was similar for all patients, while for the two-step IMRT approach it was patient specific. CONCLUSIONS: An efficient step-and-shoot IMRT solution was developed for the treatment of breast cancer using DMPO combined with two predefined segments.
Keywords: Algorithms; Breast Neoplasms/*radiotherapy; Humans; Radiotherapy Dosage; Radiotherapy, Intensity-Modulated/instrumentation/*methods
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Valtersson, U., Hansson Mild, K., & Mattsson, M. - O. (1997). Ornithine decarboxylase activity and polyamine levels are different in Jurkat and CEM-CM3 cells after exposure to a 50 Hz magnetic field. Bioelectrochemistry and Bioenergetics, 43(1), 169–172.
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Valera, E. T., Brassesco, M. S., & Tone, L. G. (2014). Electromagnetic fields at extremely low frequencies and the risk for childhood leukemia: do we have enough information to warrant this association? Leuk Res, 38(3), 289.
Keywords: Female; Humans; Magnetic Fields/*adverse effects; Male; Precursor Cell Lymphoblastic Leukemia-Lymphoma/*etiology; Cancer risk; Childhood leukemia; Electromagnetic field; Leukemogenesis
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Valbonesi, P., Franzellitti, S., Bersani, F., Contin, A., & Fabbri, E. (2014). Effects of the exposure to intermittent 1.8 GHz radio frequency electromagnetic fields on HSP70 expression and MAPK signaling pathways in PC12 cells. International Journal of Radiation Biology, 90(February), 382–391.
Abstract: Abstract Purpose: We previously reported effects on heat shock protein 70 (HSP70) mRNA expression, a cytoprotective protein induced under stressful condition, in human trophoblast cells exposed to amplitude-modulated Global System for Mobile Communication (GSM) signals. In the present work the same experimental conditions were applied to the rat PC12 cells, in order to assess the stress responses mediated by HSP70 and by the Mitogen Activated Protein Kinases (MAPK) in neuronal-like cells, an interesting model to study possible effects of mobile phone frequencies exposure. Materials and methods: HSP70 gene expression level was evaluated by reverse transcriptase polymerase chain reaction, HSP70 protein expression and MAPK phosphorylation were assessed by Western blotting. PC12 cells were exposed for 4, 16 or 24 h to 1.8 GHz continuous wave signal (CW, carrier frequency without modulation) or to two different GSM modulation schemes, GSM-217Hz and GSM-Talk (which generates temporal changes between two different GSM signals, active during talking or listening phases respectively, thus simulating a typical conversation). Specific adsorption rate (SAR) was 2 W/kg. Results: After PC12 cells exposure to the GSM-217Hz signal for 16 or 24 h, HSP70 transcription significantly increased, whereas no effect was observed in cells exposed to the CW or GSM-Talk signals. HSP70 protein expression and three different MAPK signaling pathways were not affected by the exposure to any of the three different 1.8 GHz signals. Conclusion: The positive effect on HSP70 mRNA expression, observed only in cells exposed to the GSM-217Hz signal, is a repeatable response previously reported in human trophoblast cells and now confirmed in PC12 cells. Further investigations towards a possible role of 1.8 GHz signal modulation are therefore advisable.
Keywords: gsm-217 signal; hsp70; mapk; stress response
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Vacha, M., Puzova, T., & Kvicalova, M. (2009). Radio frequency magnetic fields disrupt magnetoreception in American cockroach. J Exp Biol, 212(Pt 21), 3473–3477.
Abstract: The sense that allows birds to orient themselves by the Earth's magnetic field can be disabled by an oscillating magnetic field whose intensity is just a fraction of the geomagnetic field intensity and whose oscillations fall into the medium or high frequency radio wave bands. This remarkable phenomenon points very clearly at one of two existing alternative magnetoreception mechanisms in terrestrial animals, i.e. the mechanism based on the radical pair reactions of specific photosensitive molecules. As the first such study in invertebrates, our work offers evidence that geomagnetic field reception in American cockroach is sensitive to a weak radio frequency field. Furthermore, we show that the 'deafening' effect at Larmor frequency 1.2 MHz is stronger than at different frequencies. The parameter studied was the rise in locomotor activity of cockroaches induced by periodic changes in the geomagnetic North positions by 60 deg. The onset of the disruptive effect of a 1.2 MHz field was found between 12 nT and 18 nT whereas the threshold of a doubled frequency field 2.4 MHz fell between 18 nT and 44 nT. A 7 MHz field showed no impact even in maximal 44 nT magnetic flux density. The results indicate resonance effects rather than non-specific bias of procedure itself and suggest that insects may be equipped with the same magnetoreception system as the birds.
Keywords: Animals; *Electromagnetic Fields; *Magnetics; Motor Activity/physiology; Perception/*physiology; Periplaneta/*physiology; *Radio Waves
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