此篇論文主要是探討極低頻電磁場對乳腺癌細胞MDA-MB-231的影響。在磁場強度0.82 mT下，我們測試了7.83-pause-60 Hz和7.83-pause-7.83 Hz兩種頻率對細胞的影響。我們發現當EMF暴露系統在開關為開啟1小時後關閉5小時的循環下，兩種頻率分別在不同的總實驗時間對細胞的活性影響最大：7.83-pause-60 Hz在24小時影響最大，7.83-pause-7.83 Hz則是48小時。接著我們測試在暴露過程中更換頻率對細胞活性的影響。在實驗時間固定為48小時下，第一天暴露7.83-pause-60 Hz，第二天暴露7.83-pause-7.83 Hz時，實驗組細胞活性相對控制組有顯著降低；但當兩頻率的暴露順序交換後，EMF對細胞活性的影響就減弱了。為此我們測試了兩頻率的各別影響，推測此現象可能與暴露時的細胞密度有關，最後透過實驗驗證我們的猜測。兩頻率受細胞密度的影響不同，7.83-pause-60 Hz在細胞密度高時效果減弱，7.83-pause-7.83 Hz受細胞密度影響相對較小。
許多研究指出極低頻電磁場對於細胞的效果受頻率、磁場大小、波形等諸多因素影響，會造成細胞週期停滯、細胞凋亡等效應。此篇論文提出細胞密度可能也是造成電磁場對細胞有效與否的因素之一，但關於這方面的研究尚未完善，有值得深入研究的價值。

This paper discusses the effects of extremely low frequency electromagnetic fields (ELF-EMF) on breast cancer cells MDA-MB-231. With a magnetic field strength of 0.82 mT, we tested the effects of two frequencies, 7.83-pause-60 Hz and 7.83-pause-7.83 Hz, on cells. We found that when the EMF exposure system was turned on for 1 hour and then turned off for 5 hours, the two frequencies had the greatest effect on cell viability at different total experimental times: 7.83-pause-60 Hz has the greatest effect at 24 hours, and 7.83 -pause-7.83 Hz is 48 hours. Then we tested the effect of altered frequency on cell viability during the exposure process. The experiment time was fixed at 48 hours, when exposure to 7.83-pause-60 Hz on the first day and 7.83-pause-7.83 Hz on the second day, the cell viability of the experimental groups was significantly lower than that of the control groups. However, when the exposure sequence of the two frequencies was exchanged, the effect of the EMF on cell viability was weakened. For this reason, we tested the respective effects of the two frequencies and assumed that this phenomenon may be related to the cell density at the time of exposure, and finally verified our suppose through experiments. The two frequencies are affected differently by cell density. 7.83-pause-60 Hz has a weaker effect when the cell density is high, and 7.83-pause-7.83 Hz is relatively less affected by cell density.
Many studies have pointed out that the effect of ELF-EMF on cells is affected by many factors such as frequency, magnetic field strength, waveform, etc., which can cause cell cycle arrest, cell apoptosis and other effects. This paper proposes that cell density may also be one of the factors that affects the effect of EMF on cells, but the research on this area is not yet complete, and it is worthy of in-depth study.

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