نتایج جستجو برای: uv b exclusion

تعداد نتایج: 1041609  

2007
F. Karaca

The Pentaneand Toluene-Soluble Fractions of a Petroleum Residue and three Coal Tars by Size Exclusion Chromatography and UV-Fluorescence Spectroscopy — A petroleum atmospheric pressure distillate residue and three tars derived from different coals using different severities of thermal treatment were separated into seven fractions using column chromatography on silica and sequential elution by t...

Journal: :Infection and immunity 2000
K Yamamoto R Ito M Koura T Kamiyama

We here examined whether exposure of mice to UV-B affected their susceptibility to the murine malaria parasite Plasmodium chabaudi. When BALB/c mice with depilated skin were irradiated with UV-B and subsequently infected with the parasite, 80 to 100% of the UV-B-irradiated mice died within 12 days of infection with a sublethal dose. In addition, UV-B irradiation of C57BL/10 (B-10) mice, which a...

Journal: :Plant physiology 1994
C. R. Caldwell

The effect of ultraviolet B (UV-B) radiation on the thermal sensitivity of cucumber (Cucumis sativus L.) was studied using UV-B-sensitive cv Poinsett 76 and UV-B-resistant cv Ashley grown under control and elevated (300 mW m-2) UV-B radiation levels. Using both cotyledon and leaf discs, the ability of the tissue to reduce triphenyl tetrazolium chloride (TTC) was determined after treatment at 50...

2005
Susan A. Collins

Ultraviolet-B (UV-B) radiation can have wide-ranging impacts on plants. UV-B exposure can decrease the rate of photosynthesis, alter pigment concentrations, and damage DNA, proteins, and lipids; however, not all species are equally sensitive. Lemna minor and Spirodela polyrhiza, two sympatric aquatic plants, were exposed to 5 or 11 days of artificial UV-B radiation for 6 hours per day, and moni...

2004
Johann G. Zaller Peter S. Searles Martyn M. Caldwell Stephan D. Flint Ana L. Scopel Osvaldo E. Sala

Solar ultraviolet-B radiation (UV-B, 280–315 nm) in the Southern Hemisphere has been increasing over the last few decades due to seasonal stratospheric ozone depletion associated with the ‘ozone hole’ and a more general erosion of the stratospheric ozone layer. We studied the effect of UV-B radiation on growth responses of Carex curta and C. decidua, the two most dominant sedges in a fen ecosys...

Journal: :The New phytologist 2007
Kathleen Hectors Els Prinsen Wim De Coen Marcel A K Jansen Yves Guisez

Ultraviolet B (UV-B) acclimation comprises complex and poorly understood changes in plant metabolism. The effects of chronic and ecologically relevant UV-B dose rates on Arabidopsis thaliana were determined. The UV-B acclimation process was studied by measuring radiation effects on morphology, physiology, biochemistry and gene expression. Chronic UV-B radiation did not affect photosynthesis or ...

Journal: :Photochemistry and photobiology 2004
Gordon M Heisler Richard H Grant Wei Gao James R Slusser

Ultraviolet-B radiation (UV-B, 280-320 nm) has important effects in urban areas, including those on human health. Broadband UV-B radiation is monitored in Baltimore, MD, as part of the Baltimore Ecosystem Study, a long-term ecological research program. We compare broadband UV-B irradiance in Baltimore with UV-B at two nearby locations: a more rural station 64 km southeast and a suburban station...

2016
Xuan Ma Yong-Bin Ou Yong-Feng Gao Stanley Lutts Tao-Tao Li Yang Wang Yong-Fu Chen Yu-Fang Sun Yin-An Yao

The effects of moderate salinity on the responses of woody plants to UV-B radiation were investigated using two Populus species (Populus alba and Populus russkii). Under UV-B radiation, moderate salinity reduced the oxidation pressure in both species, as indicated by lower levels of cellular H2O2 and membrane peroxidation, and weakened the inhibition of photochemical efficiency expressed by O-J...

Journal: :Photochemistry and photobiology 2006
Paul C Frost Alyson Mack James H Larson Scott D Bridgham Gary A Lamberti

We examined UV-B radiation flux and its environmental control within and among streams of northern Michigan. UV-B flux was estimated in streams by plastic dosimetry strips, which allow for the simultaneous and repeated in situ measurement of solar radiation. During the summer of 2004, UV-B flux was measured across depth gradients and along longitudinal transects in seven streams, which were cho...

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