Light exposure tests

Table IV. Books Selected for Light Exposure Tests after Modified Diethyl Zinc Treatment0...

Filaments were subjected to storage testing at elevated temperatures and high humidity as well as light exposure testing. Testing results are provided in Table 1. 

The light exposure test matrix includes six core experiments. L-1 is a baseline experiment for the light exposure series it examines the effeets of photolysis reaetions on the exhaust composition. Experiment L-2 examines the effeet of HO reactions on exhaust composition at relatively high NOx. Experiment L-3 is proposed to examine the effect of the... 

Louis et al. (1973) got negative results from provocation tests with the xenon high-pressure lamp and epicutaneous light exposure tests without and with detachment of the stratum corneum in patients with bullous photodermatitis after nalidixic acid. However, they were able to demonstrate the phototoxicity of nalidixic acid by means of the Daniels Candida test. 

Tables 2—5 Hst some typical properties or ranges of properties for the more common film and sheet products. Although these values are good for comparative purposes, actual performance tests are best to determine suitabiHty for use. Properties of multiple-layer films or sheets in laminar stmctures cannot always be predicted from values for the individual polymer layers. Use conditions of stress, temperature, humidity, and light exposure all strongly influence performance. Film and sheet manufacturers can recommend product combinations or variations that may provide significant performance advantages to the user.

Obviously, use of such databases often fails in case of interaction between additives. As an example we mention additive/antistat interaction in PP, as observed by Dieckmann et al. [166], In this case analysis and performance data demonstrate chemical interaction between glycerol esters and acid neutralisers. This phenomenon is pronounced when the additive is a strong base, like synthetic hydrotalcite, or a metal carboxylate. Similar problems may arise after ageing of a polymer. A common request in a technical support analytical laboratory is to analyse the additives in a sample that has prematurely failed in an exposure test, when at best an unexposed control sample is available. Under some circumstances, heat or light exposure may have transformed the additive into other products. Reaction product identification then usually requires a general library of their spectroscopic or mass spectrometric profiles. For example, Bell et al. [167] have focused attention on the degradation of light stabilisers and antioxidants... 

Immediately after the dose application, the animals are placed in a restraint while the test sites are kept uncovered. Prior to irradiation the heads are covered to prevent ocular damage from the light exposure. 

The test is based on an in vitro assay of the uptake of the dye, neutral red (NR), in Balb/c 3T3 fibroblasts. It was developed to detect the phototoxicity induced by the combined interaction of the test substance and light of the wavelength range from 315 to 400 nm, the so-called UVA. The cytotoxicity is evaluated in the presence (+UVA) or absence (-UVA) of UVA light exposure, after application of a nontoxic dose of the compound. The cytotoxicological impact is assessed via the inhibition of the fibroblasts to take up the vital dye NR (NR is a weak cationic dye, penetrating easily into the cell membrane by a nonionic diffusion and accumulates in the lysosomes) one day after the initial treatment. Normally, healthy cells may incorporate and bind NR. Alterations of the cell surface or the lysosomal membranes, however, lead to a decreased uptake and binding of the dye. 

Fastness against light. These tests should be made both under glass and in the open air and are always relative to the duration of the exposure and to the season in which they are made. 

Observe the test strip to determine the proper amount of time for light exposure to make a clear, detailed print. 

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