The rate of tumor induction by UV-A radiation rises more slowly with time and accumulated dose than that by UV-B radiation. It has recently been shown that this difference disappears when frank papillomas are excluded from the analysis. Thus, the rate of development of "nonpapillomas" (mainly squamous cell carcinomas and precursors) can be fully characterized by a typical tumor induction time, ...

The study focuses on the effect of supplemental UV-B radiation on germination, seedling growth, chlorophyll a and b contents, soluble phenols, anthocyanins, flavones contents, phenylalanine ammonia lyase (PAL) activity and tyrosine ammonia lyase (TAL) activity of mash-bean (Vigna mungo (L.) Hepper.). Even though the germination velocity was substantially increased, the final germination percent...

It has been said that aside from skin, the organ most susceptible to sunlight-induced damage is the eye. In view of this, it can be argued that the optical industry and the eye care professional have an obligation, or at least, an opportunity, to educate the public more widely on the dangers of ocular exposure to UV and how best to achieve protection. This article summarises our understanding o...

Apoptosis or programmed cell death is a key function in regulating skin development, homeostasis and tumorigenesis. The epidermis is exposed to various external stimuli and one of the most important is UV radiation. The UVA and UVB spectra differ in their biological effects and in their depth of penetration through the skin layers. UVB rays are absorbed directly by DNA which results in its dama...

OBJECTIVE To determine the effectiveness of a UV-C-emitting device to eliminate clinically important nosocomial pathogens in a contaminated hospital room. METHODS This study was carried out in a standard but empty hospital room (phase 1) and in a room previously occupied by a patient with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) infection (...

The survivability of resistant terrestrial microbes, bacterial spores of Bacillus subtilis, was investigated in the BIOPAN facility of the European Space Agency onboard of Russian Earth-orbiting FOTON satellites (BIOPAN I -III missions). The spores were exposed to different subsets of the extreme environmental parameters in space (vacuum, extraterrestrial solar UV, shielding by protecting mater...

Stratospheric ozone depletion leads to enhanced UV-B radiation. Therefore, the capacity of reproductive cells to cope with different spectral irradiance was investigated in the laboratory. Zoospores of the upper sublittoral kelp Saccorhiza dermatodea were exposed to varying fluence of spectral irradiance consisting of photosynthetically active radiation (PAR, 400-700 nm; =P), PAR+UV-A radiation...

Halo nevi, also termed Sutton nevi, are defined as benign melanocytic nevi that are surrounded by an area of depigmentation resembling a halo. Halo nevi are common in children and young adults, with a mean age at onset of 15 years. The incidence in the population is estimated to be approximately 1%. Affected individuals frequently have multiple lesions which are usually localized on the back. A...

UV radiation (UV) is classified as a "complete carcinogen" because it is both a mutagen and a non-specific damaging agent and has properties of both a tumor initiator and a tumor promoter. In environmental abundance, UV is the most important modifiable risk factor for skin cancer and many other environmentally-influenced skin disorders. However, UV also benefits human health by mediating natura...

background: despite their simplicity and the low-cost, the conventional non-contact uv systems have low efficiency in water disinfection. the purpose of this study was to examine the possibility of upgrading these systems by some modifications in order to maximize the water contact with the uv radiation and as a result a better disinfection.    methods: in this study, two enhanced models of non...