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Direct Ultraviolet Effects on Biological Systems
Published in Thomas M. Nordlund, Peter M. Hoffmann, Quantitative Understanding of Biosystems, 2019
Thomas M. Nordlund, Peter M. Hoffmann
Action spectra are defined by the extent of a specific photon-initiated effect as a function of the wavelength of excitation light. The O2 production spectrum measured by Emerson and Arnold (Chapter 10) was such an action spectrum. In the present case the “action” we are considering is some sort of quantifiable damage or impairment to an organism or molecule caused by photon absorption. Because photon absorption is statistical in nature, specific chemical outcomes that may follow absorption in only a small fraction of the cases will be even more strongly governed by statistics. Finally, if the measured outcome is death of a cell, the statistical variation in cell “hardiness” will come strongly into play. Such spectra can be measured on an absolute scale, such as the amount of energy needed to cause 50% of the maximal effects (e.g., death of 50% of the cells in a sample), or more commonly, on a relative scale.
Ultraviolet radiation dosimetry
Published in Indra J. Das, Radiochromic Film, 2017
Martin Butson, Samara Alzaidi, Mamoon Haque
An action spectrum is defined as the rate of change/reaction of some form of physiological activity compared with the wavelength of the incident light [21]. In relation to UV radiation action spectra, for biological reactions, it defines a parameter function that describes the relative effect of energy at different wavelengths in producing a certain biological response. These effects may be at a molecular level, such as DNA damage or erythema response of skin through to effects on a whole organism, such as plant growth. An action spectrum is used as a weighting function for the UV spectrum in an integration of the monochromatic UV irradiance.
A Review of Human Physiological Responses to Light: Implications for the Development of Integrative Lighting Solutions
Published in LEUKOS, 2022
Céline Vetter, P. Morgan Pattison, Kevin Houser, Michael Herf, Andrew J. K. Phillips, Kenneth P. Wright, Debra J. Skene, George C. Brainard, Diane B. Boivin, Gena Glickman
The method for determining the spectral sensitivity of a photoreceptor is via the construction of an action spectrum, which is by definition, the relative response of a living organism to different wavelengths of visible and near-visible electromagnetic radiation (Horspool and Lenci 2003). Action spectra studies have served to elucidate underlying physiology while simultaneously providing practical guidance for optimizing the spectral quality of light for human health.