We describe a simple method for generating sub-20-fs ultraviolet light pulses with useful average powers, using a kilohertz Ti:sapphire laser system. By focusing a 22-fs, 1-mJ laser pulse in air, we obtain ultraviolet pulses with an energy of 1 microJ and at a wavelength of 266 nm and with an average power of 1 mW. The pulse duration of the ultraviolet pulses was measured to be 16 fs with frequ...

Pre-irradiation starvation of exponentially growing Escherichia coli B/r Hcr+ thy-try- strain for thymine and tryptophan causes inhibition of pyrimidine dimer excision from ultraviolet damaged cells DNA. This inhibition of excision repair has not resulted in increasing ultraviolet sensitivity nor in increasing frequency of ultraviolet induced tryptophan revertants. The possible mechanisms of th...

The nonoxidizing catalytic noble metal rhodium is introduced for ultraviolet plasmonics. Planar tripods of 8 nm Rh nanoparticles, synthesized by a modified polyol reduction method, have a calculated local surface plasmon resonance near 330 nm. By attaching p-aminothiophenol, local field-enhanced Raman spectra and accelerated photodamage were observed under near-resonant ultraviolet illumination...

The vision of Culex quinquefasciatus was studied in the laboratory. The attractiveness of colors (black, white, brown, yellow, blue, a skin tone) was evaluated with respect to the collection of Cx. quinquefasciatus in natural light, in the dark, and in ultraviolet light. Culex quinquefasciatus prefers both black and brown in natural light and ultraviolet light, but, as expected, there is no pre...

A growth-chamber experiment was conducted to evaluate whether ethylenenediurea (EDU), a chemical shown to be protective against ozone pollution, could ameliorate foliar damage induced by ultraviolet-B (UV-B) radiation exposure in 'Roanoke' soybean (Glycine max L.), a UV-B-sensitive cultivar, and whether these effects could be discriminated using fluorescence (F) observations. The experiment had...

Increases in the terrestrial levels of ultraviolet-B (UV-B) radiation (280 to 320 nm) due to diminished stratospheric ozone have prompted an investigation of the protective mechanisms that contribute to UV-B tolerance in plants. In response to UV-B stress, flowering plants produce a variety of UV-absorptive secondary products derived from phenylalanine. Arabidopsis mutants with defects in the s...

background : farmers and welders who work in open spaces and are exposed to direct sunlight are often exposed to sunlight radiation o n the neck and head . thus, they may be afflicted with various types of skin cancer . the aim of the present study was to investigate the amount of uv exposure in welders working in shahrud city , iran .   materials and method s : this cross-sectional , descripti...

Ultraviolet-B (UV-B) radiation and elevated tropospheric ozone may cause reductions in the productivity and quality of important agricultural crops. However, research regarding their interactive effect is still scarce, especially on the belowground processes. Using the open top chambers experimental setup, we monitored the response of soil nematodes to the elevated O3 and UV-B radiation individ...

Ultraviolet B radiation (UV-B) is an important environmental driver that can affect locomotor performance negatively by inducing production of reactive oxygen species (ROS). Prolonged regular exercise increases antioxidant activities, which may alleviate the negative effects of UV-B-induced ROS. Animals naturally performing exercise, such as humans performing regular exercise or fish living in ...