With organic dyes

Rather early in the evolution of bacteriology it was noted that these single-celled organisms readily stain with organic dye molecules. An elaborate classification scheme can in fact be de-... 

Optical fibres composed of plastics are also transparent in the visible spectral region but optical losses reach 102 - 103 dB/km13. Their refractive index varies from 1.35 to 1.6 depending on the kind of polymer used (e.g. polymethymethacrylate PMMA -1.49). The chemical resistance is much worse than that of silica fibres and thermal stability is incomparable. On the other hand, low temperature processes of plastic fibre preparation allow us mix the starting polymer with organic dyes which enables the production of luminescent fibres suitable e.g. for fluorescence-based sensing13. 

Clapp AR, Medintz IL, Fisher BR, Anderson GP, Mattoussi FI (2005) Can luminescent quantum dots be efficient energy acceptors with organic dye donors J Am Chem Soc 127 1242-1250... 

Collective Effects Observed with Organic Dyes. 116... 

Much effort has been made to establish the optimum distance between the dye and the surface of the metal particle. If fluorescence from a molecule or nanoparticle is directly adsorbed onto the surface of a metallic particle, it is strongly quenched due to electron transfer, and if the distance is too large, the enhancement effect has again to vanish there should, therefore, be an optimal distance for the observation of the enhancement effect. Based on experiments with organic dyes [84, 85] and Quantum Dots [80], this distance should be 5-10 nm. 

Abstract Silver clusters, composed of only a few silver atoms, have remarkable optical properties based on electronic transitions between quantized energy levels. They have large absorption coefficients and fluorescence quantum yields, in common with conventional fluorescent markers. But importantly, silver clusters have an attractive set of features, including subnanometer size, nontoxicity and photostability, which makes them competitive as fluorescent markers compared with organic dye molecules and semiconductor quantum dots. In this chapter, we review the synthesis and properties of fluorescent silver clusters, and their application as bio-labels and molecular sensors. Silver clusters may have a bright future as luminescent probes for labeling and sensing applications. 

Although many individual biomolecular functions have already been studied by labeling bioactive molecules, proteins, antibodies and DNA strands with organic dyes and quantum dots, the extraordinary properties of silver clusters suggest that these species might be competitive alternatives (Table 1 and Fig. 11a). Nevertheless, silver clusters present some disadvantages in their application to biological systems. 

In contrast to the situation with organic dyes, inorganic anions seem to show no dependence of the rate constants on the degree of solvation. 

The mechanism of optical recording with organic dyes involves converting the excitation energy, generated by the focused laser beam, into thermal energy by non-... 

In the years since 1964, when the first passive Q-switching with organic dyes was accomplished, the use of organic dyes in laser technology has become increasingly important. Some of the most important developments in the laser field would not have been possible without organic dyes, and one can foresee even further possibilities for the use of dyes in laser technology which could be realized in the near future. 

As in inorganic photoconductors, with organic dyes and other organic compounds, too, photocurrents and photovoltages may be observed without the application of auxiliary voltages. The following effects may be mentioned. 

Good minium should not be adulterated with extraneous substances or "improved with organic dyes. Good commercial qualities usually contain 1-6% of insoluble matter and the best sometimes less than 1% in any case not more than 10% of insoluble residue should be allowed. 

Cinnabar or vermilion should not contain more than minimal traces of extraneous substances and should not leave more than traces of fixed residue on calcination they should not be " improved with organic dyes. Vermilion in particular should be as free as possible from free mercury and mercuric nitrate, which lower its stability. 

It is often improved with organic dyes (generally malachite green or one of its allies) and sometimes with copper green. It may, indeed, be replaced by inert matter coloured with artificial organic dyes. 

Korovin, Y. and Rusakova, N. (2002) Near infrared luminescence of lanthanides in complexes with organic dyes. Journal of Fluorescence, 12, 159. 

Horn can be bleached to a pale opaque colour with an almost iridescent sheen. This was seen m art nouveau jewellery (Pig. 7.13). Horn can be dyed, as a rule with organic dyes. The dyed colour is only on the surface. In rhin layers dyed hom could be used as coloured veneer on fumituie. 

In this chapter, we discuss core-shell semiconductor quantum dots and their applications in biological labeling (Fig. 12.1). In comparison with organic dyes and fluorescent proteins, semiconductor quantum dots represent a new class of fluorescent labels with unique advantages and applications. For example, the fluorescence emission spectra of quantum dots can be continuously tuned by changing the particle size, and a single wavelength can be used for simultaneous excitation of all different-sized QDs. 

Field testing is often done in order to locate existing or suspected flow channels, and to establish the locations of their exposed terminals. Such tests are an important phase of seepage control work, and are almost always performed with organic dyes (see Chap. 16). Dye testing, as well as field pumping tests, should be done with the grout plant to be used on the project. 

The coloured adsorption compounds formed by Mg(OH)2 with organic dyes are essential parts of the methods for determining magnesium (e.g., the Titan Yellow method). Other methods are based on soluble coloured magnesium complexes formed with some organic reagents (e.g., Eriochrome Black T) in ammoniacal media. 

Mustroph, H., Stollenwerk, M., Bressau, V., Current Developments in Optical Data Storage with Organic Dyes, Angew. Chem. Int. Ed. 2006, 45, 2016 2035. 

The isotope 238U is available in rather large quantities at a low cost, as a by-product of isotope separation enriching from its abundance 0.7% in minerals. We discuss the combinations with organic dye-stuffs and the protection against their photo-degradation in Sect. 8. 

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