scholarly journals Far ultra-violet radiation : stars, nebulae and interstellar matter

1965 ◽  
Vol 23 ◽  
pp. 133-139 ◽  
Author(s):  
M. J. Seaton
Keyword(s):  
Uv Radiation ◽  
Thermodynamic Equilibrium ◽  
Local Thermodynamic Equilibrium ◽  
Ultra Violet ◽  
Interstellar Matter ◽  
Molecular Absorption ◽  
Hot Stars ◽  
Interstellar Absorption ◽  
Ultra Violet Radiation ◽  
Violet Radiation

The ultra-violet flux radiated by hot stars is found to be smaller than the value deduced from theory. The possible origins of this discrepancy are discussed : interstellar absorption, deviation from local thermodynamic equilibrium, molecular absorption, blanketting effect. Observations of planetary nebulae provide data about UV radiation from very hot stars.

scholarly journals Overall study on molecular pathways of skin cancer derived from Ultra- violet radiation as an environmental threat

2015 ◽  
Vol 16 (SE) ◽  
pp. 547-555
Author(s):  
Hossein Yousefi ◽  
Samira Mohammadzadeh ◽  
Arsalan Irompour ◽  
Neda Shenasifam ◽  
Elham Roshandel ◽  
...  
Keyword(s):  
Skin Cancer ◽  
Ultraviolet Radiation ◽  
Cell Carcinoma ◽  
Uv Radiation ◽  
Ultra Violet ◽  
Ozone Layer ◽  
Molecular Pathways ◽  
Ultra Violet Radiation ◽  
Environmental Threat ◽  
Violet Radiation

An important part of solar radiation is considered to be Ultraviolet radiation. Though through passing ozone layer it is progressively filtered. Due to the depletion of the ozone layer, the filtering activity of the latter is reduced and as a result more UV radiation, UVB in particular, reaches the Earth’s surface. Ultraviolet radiation is composed of three different wavelengths: UVA, UVB and UVC. Although UVC isn't a cause of skin cancer, UVA and UVB play different roles as for tanning, burning, and photo aging. As a matter of fact, Ultraviolet light can damage DNA in the epidermis. However, through apoptosis the damaged DNA is repaired or deleted in order to prevent the generation of cancer. It is believed that a deficient apoptotic mechanism might make individuals liable to skin cancer. The main factor for generating skin cancer is considered to be the UV radiation which could cause basal cell carcinoma, squamous cell carcinoma and possibly melanoma. For the maintenance of hemostasis, apoptosis plays a key role. This is done via many molecular pathways such as the pathways of tumor suppressor genes like P53, P21 and also the expression of BAX proteins. These pathways are involved in apoptosis after UV radiation. It is clear that the malfunction of these genes and proteins can lower the tolerance of body and cause cancer. The goal of this article is to investigate the molecular pathways of skin cancer derived from Ultra violet radiation as an environmental threat.

Ultra-Violet Radiation and Varicose Ulcers

BMJ ◽  
1927 ◽  
Vol 2 (3479) ◽  
pp. 472-472
Author(s):  
M. Weinbren
Keyword(s):  
Ultra Violet ◽  
Ultra Violet Radiation ◽  
Violet Radiation

Ultra-Violet Radiation and the Production of Twins and Double Monsters

1931 ◽  
Vol 4 (3) ◽  
pp. 461-485 ◽  
Author(s):  
Marie A. Hinrichs ◽  
Ida T. Genther
Keyword(s):  
Ultra Violet ◽  
Ultra Violet Radiation ◽  
Violet Radiation

scholarly journals Extensive reduction of surface UV radiation since 1750 in world's populated regions

2009 ◽  
Vol 9 (20) ◽  
pp. 7737-7751 ◽  
Author(s):  
M. M. Kvalevåg ◽  
G. Myhre ◽  
C. E. Lund Myhre
Keyword(s):  
Uv Radiation ◽  
Correlation Coefficients ◽  
Ultra Violet ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Polar Regions ◽  
Ultra Violet Radiation ◽  
Wide Range ◽  
Extensive Surface ◽  
Year 2000

Abstract. Human activity influences a wide range of components that affect the surface UV radiation levels, among them ozone at high latitudes. We calculate the effect of human-induced changes in the surface erythemally weighted ultra-violet radiation (UV-E) since 1750. We compare results from a radiative transfer model to surface UV-E radiation for year 2000 derived by satellite observations (from Total Ozone Mapping Spectroradiometer) and to ground based measurements at 14 sites. The model correlates well with the observations; the correlation coefficients are 0.97 and 0.98 for satellite and ground based measurements, respectively. In addition to the effect of changes in ozone, we also investigate the effect of changes in SO2, NO2, the direct and indirect effects of aerosols, albedo changes and aviation-induced contrails and cirrus. The results show an increase of surface UV-E in polar regions, most strongly in the Southern Hemisphere. Furthermore, our study also shows an extensive surface UV-E reduction over most land areas; a reduction up to 20% since 1750 is found in some industrialized regions. This reduction in UV-E over the industrial period is particularly large in highly populated regions.

Effects of Ultra-Violet Radiation on Oysters

Nature ◽  
1958 ◽  
Vol 181 (4614) ◽  
pp. 1013-1013 ◽  
Author(s):  
I. A. ABOUL-ELA
Keyword(s):  
Ultra Violet ◽  
Ultra Violet Radiation ◽  
Violet Radiation
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