The aim of this study was to compare the effects of three cryotherapeutic modalities (ethyl chloride spraying, ice block rubbing and cold gel packing) on facial skin temperature. Thirty healthy volunteers (15 men, 15 women; mean age, 29·4 ± 3·2 years) participated in this study. Each of the three modalities was randomly applied to the skin over the right masseter muscle. The skin surface temperature was recorded at baseline and every 5 min for 60 min after the application of one of the three cryotherapeutic modalities. Immediately after application, cold gel packing demonstrated the greatest reduction in surface temperature (10·6 °C), followed by ethyl chloride spraying (4·3 °C) and ice block rubbing (3·7 °C) (P < 0·001). During the 60-min post-application period, ethyl chloride spraying and ice block rubbing produced similar skin surface temperature changes. The skin surface remained coldest for the longest period of time after cold gel packing. The median time for recovery of the baseline temperature after application of the cold gel pack was about three to four times longer than that for the other modalities (P < 0·001). Ethyl chloride spraying and ice block rubbing resulted in less reduction and faster recovery of skin surface temperature than did cold gel packing. In conclusion, ethyl chloride spraying and ice block rubbing had a limited cooling effect on the facial skin tissue and could not reduce the skin surface temperature enough for local analgesia. Moreover, the cooling effect of cold gel packing was remarkable, but not sufficient for local analgesia.

No abstract

In accordance with regulations set forth by the Ministry of Land, Infrastructure, and Transport in Korea regarding the "Flame Retardant Performance of Building Finishing Materials and Fire Spread Prevention Structure," it is mandated that semi-noncombustible materials have a total heat emission less than 8 MJ/m2. Consequently, our study aimed to determine the ideal quantity of flame-retardant treatment required to meet the fire safety standards for Korean larch and Japanese cedar, commonly used exterior materials in Korean construction. To this end, we investigated using a cone calorimeter to observe changes in the THR (Total Heat Released) based on the AFI (Amount of Flame-retardant Impregnation) in Korean larch and Japanese cedar. Our findings indicated that the AFI needed to satisfy the prescribed flame-retardant standard of 8 MJ/m2 was THR 299 MJ/m2 for Korean larch and THR 526 MJ/m2 for Japanese cedar. As a result, we established optimal impregnation levels of flame retardant for both species.