Electronic UV dosimeters

Background/aims: The pathogenic role of ultraviolet (UV) in the development of skin cancer, skin ageing and immunosuppression makes it important to monitor human exposure to UV radiation. In a previous study we constructed UVB and UVC dosimeters based on a thermoluminescent phenomenon induced by UV in CaF₂:Dy and CaF₂ crystals. However, these dosimeters were insensitive to UVA radiation and readout was time-consuming. In the present study we aimed to develop an electronic dosimeter suitable for UVA, UVB and UVC. The principle of this dosimeter is a measure of accumulated electric current induced by UV on a photodetector.
Methods: Electric current induced by UV on a photodetector was accumulated in a Plessey's E-cell coulometer. A special reading device was constructed to quantify total charge of the coulometer. Sensitivity for UVA, UVB and UVC was achieved by the use of appropriate filters in front of the photodetector.
Results: The sensitivity of the electronic dosimeter increased with increasing wavelength of UV radiation; therefore, in UVB and UVC dosimeters the use of amplifiers was necessary. A linear response to UVA, UVB and UVC was achieved.
Conclusion: Dosimeters with a linear response to increasing doses of UVA, UVB and UVC have been constructed for personal monitoring of UV exposure.     

Targeted UV therapy in the treatment of psoriasis

Ultraviolet (UV) light is an effective treatment for extensive psoriasis and some other inflammatory skin conditions. Because the predominant effect of UV is a local one (as opposed to a systemic effect on immunity), localized delivery of ultraviolet B radiation (UVB) may be a useful treatment for localized variants of psoriasis and other conditions. The article reviews the literature regarding use of localized UV therapy. A theoretical benefit of localized UV therapy is reduced toxicity compared with whole-body therapy. Practical benefits in psoriasis treatment include higher efficacy and more appealing cosmesis compared with topicals. The 308-nm excimer laser is effective for psoriasis with fewer UVB treatments and lower total UVB exposure than needed for total body UV treatment. Other methods of localized UV delivery include quartz lamps, hand-held home UV devices, and non-laser intense photo sources. Other conditions treated with localized UV include vitiligo and lichen planus. Localized UV therapy is a useful modality for the treatment of localized variants of psoriasis with growing use for other dermatologic diseases.     

UV exposure in cars

BACKGROUND: There is increasing knowledge about the hazards of solar and ultraviolet (UV) radiation to humans. Although people spend a significant time in cars, data on UV exposure during traveling are lacking. The aim of this study was to obtain basic information on personal UV exposure in cars. METHODS: UV transmission of car glass samples, windscreen, side and back windows and sunroof, was determined. UV exposure of passengers was evaluated in seven German middle-class cars, fitted with three different types of car windows. UV doses were measured with open or closed windows/sunroof of Mercedes-Benz E 220 T, E 320, and S 500, and in an open convertible car (Mercedes-Benz CLK). Bacillus subtilis spore film dosimeters (Viospor) were attached to the front, vertex, cheeks, upper arms, forearms and thighs of 'adult' and 'child' dummies. RESULTS: UV wavelengths longer than >335 nm were transmitted through car windows, and UV irradiation >380 nm was transmitted through compound glass windscreens. There was some variation in the spectral transmission of side windows according to the type of glass. On the arms, UV exposure was 3-4% of ambient radiation when the car windows were shut, and 25-31% of ambient radiation when the windows were open. In the open convertible car, the relative personal doses reached 62% of ambient radiation. CONCLUSIONS: The car glass types examined offer substantial protection against short-wave UV radiation. Professional drivers should keep car windows closed on sunny days to reduce occupational UV exposure. In individuals with polymorphic light eruption, produced by long-wave UVA, additional protection by plastic films, clothes or sunscreens appears necessary.     

紫外线照射对浅表角质层细胞黑素的影响

为了了解紫外线照射对浅表角质层细胞黑素含量和分布的影响，用紫外线照射１２名健康志愿埂前内侧皮肤，分别于照射前后用粘附胶带取受试部位浅表角质层细胞。标本经Ｆｏｎｔａｎａ－Ｍａｓｓｏｎ银氨液处理后，用ＯｐｔｏｍａｘＶ型计算机成像分析系统测量和观察浅表角质层细胞中黑素含量和分布。结果，紫外线照射后１０ｍｉｎ，浅表角质层细胞中黑素含量与照和比较无明显差异；紫外线照射后１周，清表角质层细胞黑素含睛明显增加，     

Extreme UV exposure of professional cyclists

BACKGROUND: The most important risk factor for the development of melanoma and non-melanoma skin cancer is thought to be ultraviolet (UV) radiation. To date there is no quantification of the UV exposure of outdoor sports professionals training and competing at high solar UV levels. METHODS: During eight stages of the 'Tour de Suisse' cycling race, the UV exposure of 6 professional cyclists was monitored with Bacillus subtilis spore film dosimeters. RESULTS: The measurements showed a personal UV exposure between 0.2 minimal erythema dose (MED) during the prologue and 17.2 MED during a mountain stage. The mean daily personal exposure of all full stages (prologue excluded) was 8.1 MED. The personal exposure level determined during these races exceeded international exposure limits by more than 30 times. CONCLUSION: Therefore UV exposure of sports professionals should be limited by application of sun screens, protective clothing and training/competition at low insolation.