We describe an instrument that allows the rapid measurement of fluorescence lifetime-resolved images of leaves as well as sub-cellular structures of intact plants or single cells of algae. Lifetime and intensity fluorescence images can be acquired and displayed in real time (up to 55 lifetime-resolved images per s). Our imaging technique therefore allows rapid measurements that are necessary to determine the fluorescence lifetimes at the maximum (P level) fluorescence following initial illumination during the chlorophyll (Chl) a fluorescence transient (induction) in photosynthetic organisms. We demonstrate the application of this new instrument and methodology to measurements of: (1) Arabidopsis thaliana leaves showing the effect of dehydration on the fluorescence lifetime images; (2) Zea mays leaves showing differences in the fluorescence lifetimes due to differences in the bundle sheath cells (having a higher amount of low yield photosystem 1) and the mesophyll cells (having a higher amount of high yield photosystem 2); and (3) single cells of wild type Chlamydomonas reinhardtii and its non-photochemical quenching mutant NPQ2 (where the conversion of zeaxanthin to violaxanthin is blocked), with NPQ2 showing lowered lifetime of Chl a fluorescence. In addition to the lifetime differences referred to in (1) and (2), structural dependent heterogeneities in the fluorescence lifetimes were generally observed when imaging mesophyll cells in leaves. and O. Holub ... [et al.].
The article deals with the influence of phase modulated synthetic jet on the aerodynamics of the hump in a closed test section of the Eiffel-type wind tunnel. Three experimental methods of measurement techniques of this phenomenon, were used: the pressure profile using the Kiel total pressure probe, the velocity profile using the CTA probe and the visualization of the flow field using the hot film and the thermo camera. The experimental results with and without the influence of the synthetic jet were compared, as well the impact of the phase shift of the neighbouring synthetic jets. As a reference case, the flow around the hump without the influence of the syntheic jet was selected. The results of the measurement are presented in figures and compared. and Obsahuje seznam literatury