Net photosynthesis, growth, and ultraviolet (UV) radiation absorbance were determined for the first leaf of Cucurbita pepo L. exposed to two levels of UV-B irradiation and a UV-B radiation-free control treatment. Absorbance by extracted flavonoid pigments and other UV-B radiation-absorbing compounds from the first leaves increased with time and level of UV-B radiation impinging on leaf surfaces...

water deficit, ultraviolet radiation and carbon dioxide enrichment are the most important environmental factors in global climate change. this research was conducted in tarbiat modares university, research greenhouse and the objective of that was to study the effects of three levels of carbon dioxide (500, 900 and 1300 ppm), uv-radiation (uv-a, b and c with intensity of 18, 25 and 40 µw.cm2 res...

Research on penetration of ultraviolet (UV) radiation into human skin shows that about 20% of UVA and 10% of UVB can reach the basal layer of the epidermis. As a consequence, Langerhans cells (LCs), located in suprabasal layers, are subject to the influence of the two types of UV radiation. This phenomenon leads to quantitative and qualitative alterations in LCs, including reduction in their nu...

Exposure to X-rays, high-intensity visible light or ultraviolet radiation results in alterations to protein structure such as the breakage of disulfide bonds, the loss of electron density at electron-rich centres and the movement of side chains. These specific changes can be exploited in order to obtain phase information. Here, a case study using insulin to illustrate each step of the radiation...

Although ultraviolet radiation is potentially harmful, it is an important component of terrestrial radiation to which plants have been exposed since invading land. Since then, plants have evolved mechanisms to avoid and repair UV radiation damage. Therefore, it is not surprising that photomorphogenic responses to UV-B and UV-C are often assumed to be adaptations to harmful radiation. Most of th...

A new ultraviolet (UV)-A/B absorbing pigment with maxima at 312 and 330 nanometers from the cosmopolitan terrestrial cyanobacterium Nostoc commune is described. The pigment is found in high amounts (up to 10% of dry weight) in colonies grown under solar UV radiation but only in low concentrations in laboratory cultures illuminated by artificial light without UV. Its experimental induction by UV...