Ultraviolet radiation effects

M. Kasha, "Ultraviolet radiation effects molecular photochemistry" in Comparative Effects of Radiations. Wiley, New York, 1960. 

Ultraviolet radiation, effect on commercial polymers, 201 Ultraviolet-cured coatings hydroxy-benzotriazolc, 213 photostabilization of PVC, 213 Ultraviolet-visible spectrum,... 

Pheromones in urine will suffer degradation, hydrolysis, oxidation, and ultraviolet radiation effects. For example, the (Z)-7-12-acetyl derivative in elephant urine will gradually hydrolyze (Rasmussen, 1988). In this case, the lipoprotein carriers of the elephant acetate may also determine the life time of the signal besides serving to filter and select odorants, confer specificity, and play a critical role in the transport and transfer of an active ligand to the vomeronasal organ (Rasmussen and Schulte, 1998). 

M. Kasha, Ultraviolet radiation effects in M. Burton, J.S. Kirby-Smith and J.L. Magee, Comparative Effects of Radiation. New York Wiley, 1960. 

S.A. Diamond, G.S. Peterson, J.E. Tietge, G.T. Ankley. Assessment of the risk of solar ultraviolet radiation effects on amphibians. III. Prediction of impacts in selected northern mid-western wetlands. Environ. Sci. TechnoL, submitted. 

W.F. Vincent, A. Quesada (1994). Ultraviolet radiation effects on cyanobacteria Implications for Antarctic microbial ecosystems. In C. S. Weiler, P. A. Penhale (Eds), Ultraviolet Radiation in Antarctica Measurements and Biological Effects (pp. 111-124). American Geophysical Union, Washington, D.C. 

O. Holm-Hansen, D.Lubin (1994). Solar ultraviolet radiation effects on rates of CO2 fixation in marine phytoplankton. In N.E. Tolbert, J. Preiss (Eds), Regulation of atmospheric CO2 and O2 by photosynthetic carbon metabolism (pp. 55-74). Oxford University Press, Oxford. 

Nachtway, D.F. Caldwell, M.M. Biggs, R.H., (Eds.), 1975 in CIAP Monograph 5, Impacts of Climatic Change on the Biosphere, Part 1, Ultraviolet Radiation Effects, DOT-TST-75-55 (Washington, DC US Department of Transportation). 

Hydroxybenzophenones represent the largest and most versatile class of ulbaviolet stabilizers that are used to protect materials from the degradative effects of ulbaviolet radiation. They function by absorbing ultraviolet radiation and by quenching elecbonically excited states. 

An important effect of air pollution on the atmosphere is change in spectral transmission. The spectral regions of greatest concern are the ultraviolet and the visible. Changes in ultraviolet radiation have demonstrable adverse effects e.g., a decrease in the stratospheric ozone layer permits harmful UV radiation to penetrate to the surface of the earth. Excessive exposure to UV radiation results in increases in skin cancer and cataracts. The worldwide effort to reduce the release of stratospheric ozone-depleting chemicals such as chlorofluorocarbons is directed toward reducing this increased risk of skin cancer and cataracts for future generations. 

If the UV radiation were to reach the surface of the earth, it could have several adverse effects. A 5% decrease in ozone concentration could increase the incidence of skin cancer by 10% to 20%. Ultraviolet radiation is also a factor in diseases of the eye, including cataract formation. 

In Section 17.13 reference has been made to the influence of various substituents in the benzene ring on the absorption of ultraviolet radiation, and the purpose of this exercise is to examine the effect in the case of benzoic acid by comparing the absorption spectrum of benzoic acid with those given by 4-hydroxybenzoic acid and 4-aminobenzoic acid. 

To achieve this successful theory, Planck had discarded classical physics, which puts no restriction on how small an amount of energy may be transferred from one object to another. He had proposed instead that energy is transferred in discrete packets. To justify such a dramatic revolution, more evidence was needed. That evidence came from the photoelectric effect, the ejection of electrons from a metal when its surface is exposed to ultraviolet radiation (Fig. 1.15). The experimental observations were as follows ... 

One of the most direct methods is photoelectron spectroscopy (PES), an adaptation of the photoelectric effect (Section 1.2). A photoelectron spectrometer (see illustration below) contains a source of high-frequency, short-wavelength radiation. Ultraviolet radiation is used most often for molecules, but x-rays are used to explore orbitals buried deeply inside solids. Photons in both frequency ranges have so much energy that they can eject electrons from the molecular orbitals they occupy. 

Potential Effects of Increased Ultraviolet Radiation on the Productivity of the Southern Ocean... 

A month-long study of the effects of ultraviolet radiation (UV) on phytoplankton and ice-algae collected from Arthur Harbor, Anvers Island, Antarctica, was carried out during November-December 1987. The parameters studied included primary production rates, photosynthetic... 

Antarctic phytoplankton. In this chapter we will focus on the effects of ultraviolet radiation on Antarctic phytoplankton. We will discuss the results of an investigation which we undertook in late austral... 

Effect of UV on Productivity of the Southern Ocean. Has ozone depletion over Antarctica affected the productivity of the Southern Ocean There is no easy answer. First, one has to take into account the fact that the drastic decrease of ozone over Antarctica has been reported as recently as 1976, a relatively short time in the evolution of the organisms to develop mechanisms to cope with elevated UV. One of the most vexing problems in studying the effects of UV radiation on productivity, is a dearth of historical data on the level of UV. Without these baselines, normal fluctuations could easily be interpreted as decline in productivity. Second, there is a host of biotic and abiotic factors that play significant roles in governing the productivity of the Southern Ocean (40). Ultraviolet radiation is but one more complicating factor to be considered in an already stressful environment. 

Baker RD, Applegate HG. 1970. Effect of temperature and ultraviolet radiation on the persistence of methyl parathion and DDT in soils. Agron J 62 509-512. 

Bissett DL, Chatterjee R, Hannon DP (1990) Photoprotective effect of superoxide-scavenging antioxidants against ultraviolet radiation-induced chronic skin damage in the hairless mouse. Photodermatol Photoimmunol Photomed 7 56-62... 

As mentioned in Chapter 3, DI water has now replaced distilled water for most laboratory purposes. PVC pipe, which is both inexpensive and easy to install, is normally employed to carry the water to points of usage. It is very important that the lines do not have dead legs where water is allowed to stand, since this could encourage bacterial growth. In cases where sterile water is needed, special steps must be taken. The water may be boiled, which also drives out dissolved gases, or ultraviolet radiation may be employed, a common method in the cosmetics industry. Membrane filters will also effectively remove bacteria. Laboratories needing sterile water often use two bacteria removal systems of... 

Air or water cooled mercury discharge lamps find many uses, one of the more obvious of which is the study of photochemical reactions. These lamps are usually made of vitreous silica because of its low thermal expansion, high melting point and its transparency to ultraviolet radiation. Their operating pressure has a profound effect on the spectral distribution of the radiation produced and therefore it is important to consider the requirements in the design of such lamps. 

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