Ultraviolet light-emitting diodes (UV-LEDs) have started replacing UV lamps. The power per LED of high-power LED products has reached 12 W (14 A), which is 100 times the values observed ten years ago. In addition, the cost of these high-power LEDs has been decreasing. In this study, we attempt to understand the technologies and potential of UV-LEDs.

Ultraviolet-B (UV-B) exposure in the course of litter decomposition may have a direct effect on decomposition rates via changing states of photodegradation or decomposer constitution in litter while UV-B exposure during growth periods may alter chemical compositions and physical properties of plants. Consequently, these changes will indirectly affect subsequent litter decomposition processes in...

On the assumption that photosynthesis is a cyclic process and that irradiation by ultraviolet light does not change the reaction constants, the Blackman reaction is shown to be of first order.

1 T has been previously shown that when the polar cap cells of Drosophila (early germ track cells) are treated with various doses of ultraviolet light and the lethal mutation rate plotted against the dose, the resulting dose-rate curve rises rapidly at the lower doses employed. With further increase in dose it becomes less and less steep, and when the dose is large enough to give a detectable r...

Exposure to ultraviolet light leads to a cell-wide DNA damage response that includes a global reduction in transcription. Williamson et al., identify a protein involved in this process as well as a noncoding RNA produced by alternative processing of RNA transcribed from the same gene that promotes recovery from the repressed state.

The spore photoproduct is a unique photolesion, formed in spores upon irradiation with UV light; to investigate the properties of spore photoproduct containing DNA we have synthesized 5S and 5R lesion analogs and incorporated them into DNA.

The deactivation mechanism after ultraviolet irradiation of 2-thiouracil has been investigated using nonadiabatic dynamics simulations at the MS-CASPT2 level of theory. It is found that after excitation the S2 quickly relaxes to S1, and from there intersystem crossing takes place to both T2 and T1 with a time constant of 400 fs and a triplet yield above 80%, in very good agreement with recent f...