نتایج جستجو برای: ultraviolet radiation uv a

تعداد نتایج: 13529841  

2005
Donald T. Krizek Linda Chalker-Scott

We are pleased to bring this Symposium-in-Print on Effects of Ultraviolet Radiation on Terrestrial Ecosystems to the readers of Photochemistry and Photobiology. Six of the 10 articles contained in this Symposium-in-Print are based on invited presentations given at the symposium on ‘‘Effects of Ultraviolet Radiation on Terrestrial Ecosystems,’’ held during the American Society for Photobiology (...

Journal: :Journal of experimental botany 2011
Junmin He Xiaozhen Yue Ruibin Wang Yan Zhang

Ultraviolet B (UV-B) radiation is an important environmental signal for plant growth and development, but its signal transduction mechanism is unclear. UV-B is known to induce stomatal closure via hydrogen peroxide (H(2)O(2)), and to affect ethylene biosynthesis. As ethylene is also known to induce stomatal closure via H(2)O(2) generation, the possibility of UV-B-induced stomatal closure via et...

Journal: :The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques 2011
Scott Sloka Claudia Silva William Pryse-Phillips Scott Patten Luanne Metz V Wee Yong

BACKGROUND Multiple sclerosis (MS) is a disease with purported environmental causes. Consistent correlations have been found in various settings for latitude, smoking exposure, sunlight, and vitamin D deficiency. We analysed the contribution of various environmental factors to the risk of developing MS from a population perspective. METHODS We collated global data of MS prevalence from 54 stu...

2008
W. Kolby SMITH Wei GAO Heidi STELTZER

One of the most documented effects of human activity on our environment is the reduction of stratospheric ozone resulting in an increase of biologically harmful ultraviolet (UV) radiation. In a less predictable manner, UV radiation incident at the surface of the earth is expected to be further modified in the future as a result of altered cloud condition, atmospheric aerosol concentration, and ...

2014
Francine Behar-Cohen Gilles Baillet Tito de Ayguavives Paula Ortega Garcia Jean Krutmann Pablo Peña-García Charlotte Reme James S Wolffsohn

Ultraviolet (UV) radiation potentially damages the skin, the immune system, and structures of the eye. A useful UV sun protection for the skin has been established. Since a remarkable body of evidence shows an association between UV radiation and damage to structures of the eye, eye protection is important, but a reliable and practical tool to assess and compare the UV-protective properties of ...

Journal: :تحقیقات نظام سلامت 0

background: volatile organic compounds (vocs) are among the main air pollutants which have destructive effects on the environment and human health. considering the carcinogenic effects of some of these compounds including benzene, how to control and limit them is considered an important issue in environmental research. the aim of this study was to evaluate the use of the combined ultraviolet (u...

Journal: :Experimental dermatology 2002
Stephen E Ullrich Margaret L Kripke Honnavara N Ananthaswamy

The ultraviolet (UV) radiation present in sunlight is immune-suppressive. Recently we showed that solar-simulated UV radiation (UVA + UVB; 295-400 nm), applied after immunization, suppressed immunological memory and the elicitation of delayed-type hypersensitivity to the common opportunistic pathogen, Candida albicans. Further, we found that wavelengths in the UVA region of the solar spectrum (...

Journal: :Nutricion hospitalaria 2014
Lluvia de Abril Alexandra Soriano-Melgar Lilia Alcaraz-Meléndez Lía C Méndez-Rodríguez María Esther Puente Fernando Rivera-Cabrera Tania Zenteno-Savín

INTRODUCTION Ultraviolet type B (UV-B) radiation effects on medicinal plants have been recently investigated in the context of climate change, but the modifications generated by UV-B radiation might be used to increase the content of antioxidants, including phenolic compounds. OBJECTIVE To generate information on the effect of exposure to artificial UV-B radiation at different highdoses in th...

2009
G. K. Samanta A. Esteban-Martin M. Ghotbi M. Ebrahim-Zadeh

We describe new sources of tunable, high-power radiation in the blue and ultraviolet. Continuous-wave (cw), singlefrequency blue radiation tunable across 425-489 nm and femtosecond ultraviolet (UV) radiation tunable across 250-355 nm is generated by intracavity frequency-doubling of resonant signal radiation in cw and ultrafast optical parametric oscillators (OPOs) in singly-resonant oscillator...

Journal: :Tree physiology 1997
M A Schumaker J H Bassman R Robberecht G K Radamaker

We compared the physiological and morphological responses of rooted cuttings of Populus trichocarpa Torr. & Gray and P. trichocarpa x P. deltoides Bartr. ex Marsh. grown in either near-ambient solar ultraviolet-B (UV-B; 280-320 nm) radiation (cellulose diacetate film) or subambient UV-B radiation (polyester film) for one growing season. Midday biologically effective UV-B radiation was 120.6 and...

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