Biological Impact of Shorter Wavelength Ultraviolet Radiation-C†.

Life on earth has constantly coped with the impact of solar radiation, especially solar ultraviolet radiation (solar UV). Various biological mechanisms protect us from solar UV. New devices emitting shorter wavelengths UV-C, i.e. <254 nm emitted by conventional UV germicidal lamps, have emerged. These shorter wavelength UV-C emitting devices are useful for various purposes, including microorganism inactivation. However, as solar UV-C does not reach the earth surface, biological impacts of UV-C has been studied using 254 nm germicidal lamps, and those using shorter wavelength UV-C is rarely known. To balance the utility and risk of UV-C, the biological effect of these new UV-C emitting devices must be investigated. In addition, our knowledge of biological impacts of the wavelength-dependent entire UV (100-400 nm) must be enhanced. In this review, we briefly summarize the biological impacts of shorter wavelength UV-C. Mechanisms of UV-C-induced cellular damage and factors affecting the microorganism inactivation efficiency of UV-C have been discussed. In addition, we theoretically estimate the probable photocarcinogenic action spectrum of shorter wavelength UV-C. We propose that increasing the knowledge on UV-C will facilitate the adoption of shorter wavelength UV-C emitting new devices in an optimal and appropriate manner.

Evaluation of Acute Reactions on Mouse Skin Irradiated with 222 and 235 nm UV-C.

Biological response and DNA damage following irradiation with shorter wavelengths in the UV-C range were evaluated to investigate the safety at three wavelengths because of the recent emergence of germicidal equipment emitting short-wavelength UV-C for various purposes, including medical uses. To estimate an acceptable safety dose for human skin in the UV-C range, especially short UV-C, we studied the biological effects of 207, 222 and 235 nm UV-C using albino hairless mice and evaluated the inflammatory reactions in the skin. To explore an appropriate indicator to evaluate the biological response, we employed determination of the minimal perceptible response dose (MPRD), by which any subtle cutaneous response; erythema, edema and scale could be observed by visual inspection. Erythema was rarely observed, but edema and scale formation were evident for short UV-C wavelengths. The MPRD at 207, 222 and 235 nm was determined to be > 15, 15 and 2.0 kJ m-2 , respectively. These values could be thresholds and indicators for possible safety assessments. Our data suggest that the current human exposure limits for short UV-C wavelengths below 254 nm are overly restrictive and should be reconsidered for future disinfection lamps with short UV-C wavelengths.

Long-term Effects of 222-nm ultraviolet radiation C Sterilizing Lamps on Mice Susceptible to Ultraviolet Radiation.

Germicidal lamps that emit primarily 254 nm ultraviolet radiation (UV) are routinely utilized for surface sterilization but cannot be used for human skin because they cause genotoxicity. As an alternative, 222-nm UVC has been reported to exert sterilizing ability comparable to that of 254-nm UVC without producing cyclobutane pyrimidine dimers (CPDs), the major DNA lesions caused by UV. However, there has been no clear evidence for safety in chronic exposure to skin, particularly with respect to carcinogenesis. We therefore investigated the long-term effects of 222-nm UVC on skin using a highly photocarcinogenic phenotype mice that lack xeroderma pigmentosum complementation group A (Xpa-) gene, which is involved in repairing of CPDs. CPDs formation was recognized only uppermost layer of epidermis even with high dose of 222-nm UVC exposure. No tumors were observed in Xpa-knockout mice and wild-type mice by repetitive irradiation with 222-nm UVC, using a protocol which had shown to produce tumor in Xpa-knockout mice irradiated with broad-band UVB. Furthermore, erythema and ear swelling were not observed in both genotype mice following 222-nm UVC exposure. Our data suggest that 222-nm UVC lamps can be safely used for sterilizing human skin as far as the perspective of skin cancer development.

Surviving Hiroshima and Nagasaki--experiences and psychosocial meanings.

In spite of the fact that the A-bombings of Hiroshima and Nagasaki occurred nearly 60 years ago, there has been very little psychosocial research on the long-term effects of these unprecedented nuclear attacks on its victims. In this qualitative study, we use psychosocial literature from the Holocaust in order to help understand the effects of this man-made tragedy. We analyzed semi-structured interviews taken with 8 survivors of the bombs--5 from Nagasaki and 3 from Hiroshima. Our research questions were: When the survivors talk about their experiences, what do they focus on and with what are they preoccupied? What can we learn about the long-term effects of the experiences from both psychological and physical aspects? And, where does the A-bomb experience "fit" into the survivors' lives? Our analyses showed that there were 9 main themes that emerged from the interviews that could be grouped into two main categories--themes connected to the experience itself and themes connected to life afterward. We discuss the implications of these themes on the personal, social, and cultural levels and offer suggestions concerning ideas for dealing with the trauma.

A comparative study of Chinese, American and Japanese nurses' perceptions of ethical role responsibilities.

This article reports a survey of nurses in different cultural settings to reveal their perceptions of ethical role responsibilities relevant to nursing practice. Drawing on the Confucian theory of ethics, the first section attempts to understand nursing ethics in the context of multiple role relationships. The second section reports the administration of the Role Responsibilities Questionnaire (RRQ) to a sample of nurses in China (n = 413), the USA (n = 163), and Japan (n = 667). Multidimensional preference analysis revealed the patterns of rankings given by the nurses to the statements they considered as important ethical responsibilities. The Chinese nurses were more virtue based in their perception of ethical responsibilities, the American nurses were more principle based, and the Japanese nurses were more care based. The findings indicate that the RRQ is a sensitive instrument for outlining the embedded sociocultural factors that influence nurses' perceptions of ethical responsibilities in the realities of nursing practice. This study could be important in the fostering of partnerships in international nursing ethics.