Sensitivity to UV light

Silicone acrylates (Fig. 5) are again lower molecular weight base polymers that contain multiple functional groups. As in epoxy systems, the ratio of PDMS to functional material governs properties of release, anchorage, transfer, cure speed, etc. Radiation induced radical cure can be initiated with either exposure of photo initiators and sensitizers to UV light [22,46,71 ] or by electron beam irradiation of the sample. 

Coal tar is an effective treatment, but it is time-consuming, causes local irritation, has an unpleasant odor, stains skin and clothing, and increases sensitivity to UV light (including the sun). 

Due to their antioxidant status, carotenoids are extremely sensitive to UV light, as well as air and temperature [16]. In nature, each carotenoid occurs with several geometrical ZIE stereoisomers, which can isomerise or oxidise easily [17]. These carotenoid stereoisomers can differ considerably in their biological effectiveness, for instance in bioavailability [18,19], in quenching free radicals, or in the prevention of diseases [20]. Therefore, the unambiguous and quantitative analysis of the pattern of carotenoid stereoisomers from biological matrices is indispensable, especially with regard to dietary supplementation. 

Dosage Forms. The tocopherols, being antioxidants, are very sensitive to oxygen. Sensitivity to UV light is another problem. There are two provitamin esters that are used... 

One of the first important insights in the field of DNA repair was made after isolation of E. coli mutants with exceptional sensitivity to UV light [2] and subsequent mapping of mutations in genes designated uvrA, B, and C [3]. This led to the model of nucleotide excision repair [4,5]. Later the base excision repair pathway was exposed when Lindahl and coworkers [6,7] discovered a series of bacterial enzymes that recognized and removed modified nucleotides by a DNA N-glycosylase reaction. 

SlO ) and application of a resist layer precede the process of exposure to radiation. Different resists are sensitive to different sources of radiation UV ll ht. X-ray, E-beam, Ion beam or laser. If the resist Is sensitive to UV light, then it Is termed a photoresist and the technique Is called photolithography. In the case of E-beam lithography, the resist Is sensitive to E-beam and so on. 

The root has spasmolytic, cholagogue and carminative effects. Sunbathing should be avoided when used over long periods, since the furocoumarins make the skin sensitive to UV-light. 

By contrast, deficiencies in GG-NER (see Section 11.3) lead to the inherited disorder xeroderma pigmentosum (XP), which can be viewed as the prototypical DNA repair disorder [7-9]. XP patients are unable to repair UV lesions, and as a consequence suffer from an extreme sensitivity to UV light and an over 1000-fold increased incidence of skin cancer. Severely affected XP patients additionally suffer from neurological abnormalities. The phenotypes of two additional symptoms associated with NER genes, Cockayne syndrome (CS) and trichothiodystro-phy (TTD), are more complex as they are due to defects in transcription as well as defects in DNA repair [10]. 

Aramid is sensitive to UV light. The effects of simulated solar UV irradiation on the mechanical and structural properties of a poly(p-phenylene terephtalamide fiber have been studied." UV irradiation deteriorates the surface and defect areas of the fiber by photoinduced chain scission. 

Researchers operating with the TLC technique have some general options, shown in Fig. 1. The pure (unencapsulated) TLC substance applied in very thin films onto a flat surface offers temperature field measurements with a spatial resolution of about 800 nm. But, unencapsulated TLCs require sophisticated application techniques, and the pure TLC substance is very sensitive to UV light and contaminatirMis, particularly oxygen from the air. More common are micro-encapsulated TLCs which are stable and easier to handle. They are available as complete foils, in binder mixtures for spray applications, and as tracers. With the latter it is possible to acquire the temperature distribution in liquid flows. 

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