An Outdoor Multiple Wavelength System for the Irradiation of Biological Samples: Analysis of the Long-term Performance of Various Lamp and Filter Combinations¶

Holmes, M. G.

doi:10.1562/0031-8655(2002)076<0158:aomwsf>2.0.co;2

Cited by 10 publications

(10 citation statements)

References 8 publications

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“…However, they also provide light of wavelengths below 295 nm, which are not present in the solar spectrum at ground level (Finlayson-Pitts & Pitts, 2000). To avoid possible artifact reactions, we used a 127-μm-thick cellulose acetate film as a light filter (Holmes, 2002;Mcleod, 1997). This filter was able to remove light of wavelengths below 295 nm from the lamps emissions, as shown in Figure 1.…”

Section: Reactionsmentioning

confidence: 99%

Development and Evaluation of a Photochemical Chamber to Examine the Toxicity of Coal-Fired Power Plant Emissions

Ruíz¹,

Lawrence²,

Wolfson³

et al. 2007

Inhalation Toxicology

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When investigating the toxicity of individual particle sources, it is important to consider the contribution of both primary and secondary particles. In this article, we present the design of a new photochemical chamber that can be used to form secondary sulfuric acid particles from diluted coal-fired power plant emissions. The chamber is a relatively small, well-mixed flow reactor that can fit in a mobile reaction laboratory. It produces high concentrations of hydroxyl radical (OH) from the photolysis of ozone (O3) in the presence of water vapor. Two chambers were built and tested. A pilot chamber was tested in the laboratory, using mixtures of NO and SO2 in air, at concentrations that are approximately 100 times lower than those in power plant stack emissions. This chamber was able to oxidize about 20% of the SO2, thereby producing 1350 microg m(-3) of H2SO4 particles. Further tests showed that increasing O3 concentrations and residence time increased the H2SO4 production. A field chamber was built subsequently and used in a toxicological study. Diluted coal-fired power plant emissions were introduced in the chamber. Over 19 days of exposure, the chamber, on average, converted 17% of the supplied SO2 emissions and produced an average of 350 microg m(-3) of H2SO4 particles. Particle losses were determined for the pilot chamber, using artificial particles whose size ranged from 50 to 1000 nm. The determined losses ranged from 21 to 42%, with no trend between the amount of particle loss and particle size. Losses for the field chamber, estimated using model calculations, were found to be similar to those of the pilot chamber.

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Section: Reactionsmentioning

confidence: 99%

Development and Evaluation of a Photochemical Chamber to Examine the Toxicity of Coal-Fired Power Plant Emissions

Ruíz¹,

Lawrence²,

Wolfson³

et al. 2007

Inhalation Toxicology

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“…In particular, due to filtering by cellulose diacetate films the contribution of UV-B decreases in relation to UV-A. These aspects are often neglected in the design of experiments and have been critically discussed by several authors Teramura 1993b, 1994;Newsham et al 1996;Corlett et al 1997;Holmes 2002;White and Jahnke 2002).…”

Section: Uv Irradiationmentioning

confidence: 99%

Effects of UV irradiation on barley and tomato leaves: thermoluminescence as a method to screen the impact of UV radiation on crop plants

Gilbert

Skotnica

Weingart

et al. 2004

Functional Plant Biol.

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The effect of different UV intensities and irradiation times on barley and tomato leaves was investigated by analysis of thermoluminescence (TL) and chlorophyll (chl) fluorescence measurements. Epifluorescence microscopy was used to estimate the epidermal UV transmittance of leaves. In barley a strong supression of TL emission from the S 2 Q B − (B-band) and the S 2 Q A − (Q-band) charge recombination was observed, increasing with prolonged UV exposure. Primary barley leaves were more sensitive to UV than secondary leaves. In tomato plants a decrease in the B-band only takes place at very high UV intensities and after prolonged exposure times (4 h). The impact of UV in cotyledons was more pronounced than in pinnate leaves of tomato plants. The strong differences in sensitivity to UV in the investigated barley and tomato variety may be due to different concentrations of UV screening pigments in the epidermal layer as demonstrated by epifluorescence measurements. The results show that TL has the same potential to analyse the sensitivity or tolerance of crop plants to UV irradiation as routine fluorescence techniques. Furthermore, TL is directly monitoring the radical pair states of PSII and can distinguish between UV-induced donor and acceptor site-related damage.

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“…A majority of published reports use fluorescent lamps either as the exclusive source of UV-B or as the source of supplementary UV-B (in the case of outdoor solar radiation studies). Fluorescent UV-B lamps emit significant ultraviolet-C (UV-C, ,280 nm) and ultraviolet-A (UV-A, 320-400 nm) radiation in addition to UV-B (1)(2)(3)(4)(5)(6). Determination of the unique physiological effects of UV-B radiation requires either (1) the removal of the UV-C and UV-A portions of the irradiance or (2) accounting for the effects of the extraneous radiation.…”

Section: Introductionmentioning

confidence: 99%

“…The control exposure generally uses polyester (Mylar) to exclude UV-B from UV-A radiation sources (although a few studies imply that no such control was used). Glass or rigid plastic SWB filters are sometimes used instead of CA and Mylar (6)(7)(8)(9). This widely used protocol (termed the SWB protocol) assumes that by subtracting physiological effects attributed to UV-A exposure (i.e.…”

Section: Introductionmentioning

confidence: 99%

“…CA filtration), the residual effects must be due exclusively to UV-B. Questions have been raised as to the soundness of this assumption based on inherent inadequacies in the SWB protocol (3)(4)(5)(6)(10)(11)(12) and the dangers of ignoring complex physiological interactions between UV-A and UV-B, such as photoreactivation and other interactions (13)(14)(15)(16)(17)(18).…”

Section: Introductionmentioning

confidence: 99%

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Removing UV-A and UV-C Radiation from UV-B Fluorescent Lamp Emissions. Differences in the Inhibition of Photosynthesis in the Marine Alga Dunaliella tertiolecta Using Chromate Versus Cellulose Acetate–Polyester Filters

White

Jahnke

2004

Photochem Photobiol

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Ultraviolet-B (UV-B; 280-320 nm)-emitting lamps unavoidably emit ultraviolet-A (UV-A; 320-400 nm) and ultraviolet-C (UV-C; <280 nm) radiation. Short-wavelength-blocking filters are generally used to limit the wave bands of UV under investigation. The widespread use of such filters means that all exposures to UV-B radiation will have a significant UV-A component. Therefore, the physiological effects unique to UV-B exposure are difficult to clearly isolate. This study presents a method to remove the UV-A and UV-C "contamination" using a liquid potassium chromate (K(2)CrO(4)) filter, thus allowing more direct assessment of the effects of UV-B exposure. Cultures of the green marine alga Dunaliella tertiolecta were grown in the absence of UV radiation. Sunlamps supplied the UV radiation for a 24 h exposure (solar radiation was not used in this study). The UV radiation was filtered either by the standard method (i.e. cellulose acetate (CA) with polyester = Mylar controls) or by a liquid filter of potassium chromate. Photosynthetic responses were compared. Major decreases in the ratio of variable to maximal fluorescence in dark-adapted cells and photosynthetic capacity were observed in CA-filtered cultures, whereas no change was observed in cells exposed to the same UV-B flux with the UV-A removed by K(2)CrO(4). The use of a CA filter with a Mylar control does not link results unequivocally to UV-B radiation. Such results should be interpreted with caution.

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An Outdoor Multiple Wavelength System for the Irradiation of Biological Samples: Analysis of the Long-term Performance of Various Lamp and Filter Combinations¶

Cited by 10 publications

References 8 publications

Development and Evaluation of a Photochemical Chamber to Examine the Toxicity of Coal-Fired Power Plant Emissions

Development and Evaluation of a Photochemical Chamber to Examine the Toxicity of Coal-Fired Power Plant Emissions

Effects of UV irradiation on barley and tomato leaves: thermoluminescence as a method to screen the impact of UV radiation on crop plants

Removing UV-A and UV-C Radiation from UV-B Fluorescent Lamp Emissions. Differences in the Inhibition of Photosynthesis in the Marine Alga Dunaliella tertiolecta Using Chromate Versus Cellulose Acetate–Polyester Filters

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