iPhone charger-induced chemical burn from overnight contact with sweat: Two cases

Smartphones have become essential devices in modern society. The coverage rate of smartphones in 2017 in Japan was 75% according to the Ministry of Internal Affairs and Communications. The iPhone is one of the most well-known smartphone brands. According to the manufacturer of iPhones (Apple), more than 200 million iPhones had been sold worldwide by 2017. These devices are often charged at night-time, especially while being used in bed. There are only three reports of smartphone charger-induced skin damage. We present two new cases of skin ulcers induced by an iPhone charger. The iPhone’s “lightning cable” has electrodes outside, and we found that this can present a higher risk of causing a skin injury compared with other types of phone chargers. We also investigated the mechanism of the skin ulcers caused by the iPhone charger. The results indicated that these ulcers were chemical burns rather than an electrical injury or heat-induced burn.     

Classification of radiation effects for dose limitation purposes: history,current situation and future prospects

Radiation exposure causes cancer and non-cancer health effects, each of which differs greatly in the shape of the dose–response curve, latency, persistency, recurrence, curability, fatality and impact on quality of life. In recent decades, for dose limitation purposes, the International Commission on Radiological Protection has divided such diverse effects into tissue reactions (formerly termed non-stochastic and deterministic effects) and stochastic effects. On the one hand, effective dose limits aim to reduce the risks of stochastic effects (cancer/heritable effects) and are based on the detriment-adjusted nominal risk coefficients, assuming a linear-non-threshold dose response and a dose and dose rate effectiveness factor of 2. On the other hand, equivalent dose limits aim to avoid tissue reactions (vision-impairing cataracts and cosmetically unacceptable non-cancer skin changes) and are based on a threshold dose. However, the boundary between these two categories is becoming vague. Thus, we review the changes in radiation effect classification, dose limitation concepts, and the definition of detriment and threshold. Then, the current situation is overviewed focusing on (i) stochastic effects with a threshold, (ii) tissue reactions without a threshold, (iii) target organs/tissues for circulatory disease, (iv) dose levels for limitation of cancer risks vs prevention of non-life-threatening tissue reactions vs prevention of life-threatening tissue reactions, (v) mortality or incidence of thyroid cancer, and (vi) the detriment for tissue reactions. For future discussion, one approach is suggested that classifies radiation effects according to whether effects are life threatening, and radiobiological research needs are also briefly discussed.     

Radiation-induced apoptosis in the scid mouse spleen after low dose-rate irradiation

Purpose : To elucidate the process of radioadaptation, the role of DNA-PK activity was examined using the scid mouse defective in DNA-PKcs. Materials and methods : The induction of apoptosis in the spleens of the C.B-17 Icr scid mouse and the parental mouse was studied after chronic irradiation with γ-rays at 1.5 Gy (0.001Gy min -1 for 25 h) followed by challenge irradiation with X-rays at 3.0 Gy (1.0 Gy min -1 for 3 min). Results : When the wild-type mouse was previously exposed to chronic irradiation (1.5Gy) at a low dose-rate (0.001 Gy min -1) , apoptosis induced by acute irradiation (3.0 Gy, 1.0Gy min -1) was significantly suppressed, especially in the splenic white pulp. There was no change by acute irradiation after chronic irradiation in the scid mouse, although an effect was detected in the spleen after acute irradiation alone. Conclusions : These data suggest that DNA-PK activity might play a major role in the radioadaptive response following pre-irradiation at a low dose-rate.