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Abstract

Progress in UV treatment applications requires new compact and sensor constructions. In the paper a hybrid (organic-inorganic) rare-earth-based polymeric UV sensor construction is proposed. The efficient luminescence of poly(methyl) methacrylate (PMMA) matrix doped by europium was used for testing the optical sensor (optrode) construction. The europium complex assures effective luminescence in the visible range with well determined multi-peak spectrum emission enabling construction of the optrode. The fabricated UV optical fibre sensor was used for determination of Nd:YAG laser intensity measurements at the third harmonic (355 nm) in the radiation power range 5.0-34.0 mW. The multi-peak luminescence spectrum was used for optimization of the measurement formula. The composition of luminescent peak intensity enables to increase the slope of sensitivity up to −2.8 mW-1. The obtained results and advantages of the optical fibre construction enable to apply it in numerous UV detection systems.
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Abstract

Exposure of green algae Chlorella vulgaris to short-term UV-B radiation (280 nm – 315 nm) induced several changes in the function of photosystem II (PS II) studied by means of chlorophyll fluorescence (FL) and oxygen evolving. The intensity of photosynthetic oxygen evolving intensity of algae suspension decreased in a similar way to the FL parameter values in proportion to the applied dose of UV-B radiation (0.0, 3.2, 6.4, 12.8 kJ·m-2). The correlation between photosynthetic oxygen evolving intensity and FV/FO ratio was better than that between photosynthetic oxygen evolving intensity and FV/FM. The vitality index (Rfd) in the UV-B irradiated algae strongly decreased, compared to the control, which indicates inhibition of potential CO2 fixation and cooperation between light and dark reactions of photosynthesis. It may indicate damage of Rubisco.
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