Speckle phenomenon

An important characteristic of excimer lasers that sets them apart from traditional UV lasers is their lack of spatial coherence. The interference phenomena that result from the high spatial coherence of traditional singlemode continuous wave lasers produces a random intensity variation in projected patterns called speckle. This speckle phenomenon has historically made use of lasers in high-resolution lithography very difficult. The beam of excimer lasers is so highly multimode that speckles are, for all practical purposes, nonexistent in projected patterns. The application of excimer laser... 

Recently, a photoactivatable variant from Aequoria victoria green fluorescent protein (pa-GFP) was reported (Patterson and Lippincott-Schwartz 2002), yielding an increase in fluorescence emission intensity (at k 520 nm) by a factor of 100 when excited at k 488 nm after spectral activation at A. 408 nm. This phenomenon is due to an internal photoconversion process in the protein and allows spectral photoactivation of this protein in a very local way such as in the nucleus of a living cell (Post et al. 2005). In tobacco BY-2 protoplasts, we transiently co-expressed pa-GFP or pa-GFP fusion proteins and red-fluorescent protein (DsRed)-tagged prenylated Rab acceptor 1 (Pral At2g38360), a membrane protein that localizes in speckles around the nuclear envelope. The DsRed transfection allows proper cell identification and visualization before activation (via Pral -DsRed fluorescence). After pa-GFP... 

Evidently, ANA (first described by G.J. Friou et al. in 1957) belong to the natural autoantibodies which are continuously stimulated by a still unknown mechanism (possibly a persisting agent) in certain diseases. However, this antibody phenomenon is inconsistent and neither organ- nor disease-specific. ANA can be visualized by immunofluorescence in cryostat tissue sections of the rat liver and rat kidney as a homogeneous (s. fig. 5.10), speckled (s. fig. 5.11), circular or nuclear fluorescence pattern. This allows conclusions to be drawn as to the specificity of antinuclear antibodies and in some cases as to the nature of the underlying disease as well. 

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