Luminescence siting

Polymeric material that shows luminescence when an electric current passes through it such that charge carriers can combine at luminescent sites to give rise to electronically excited states of luminescent groups or molecules. 

In addition, the adsorption of quencher molecules, such as O2 and H2, on AEOs has allowed the clarification of the nature of the luminescence sites present at the surface [81]. In particular, in the case of H2 adsorption on SrO, a change in the excitation band shape was observed. H2 may react at different rates with species absorbing in different parts of the excitation band, producing a change in the band shape. No corresponding change in band shape was observed in the emission spectrum. By contrast, O2 adsorption did not change the shape of either the excitation or the emission bands only a decrease in intensity was observed. This... 

Ca(I) sites have been shown to be responsible for most of the observed luminescence, whereas emission from the Mn " ions on the Ca(Il) sites occur only for higher Mn concentrations. Neutron diffraction studies have also confirmed these results (10). 

The role of disorder in the photophysics of conjugated polymers has been extensively described by the work carried out in Marburg by H. Bassler and coworkers. Based on ultrafast photoluminescence (PL) (15], field-induced luminescence quenching [16J and site-selective PL excitation [17], a model for excited state thermalizalion was proposed, which considers interchain exciton migration within the inhomogenously broadened density of states. We will base part of the interpretation of our results in m-LPPP on this model, which will be discussed in some detail in Sections 8.4 and 8.6. 

To assay the amount of LBP, first an excess amount of luciferin is added to the sample at pH 8 to saturate the binding site of LBP, and then the excess luciferin is removed by gel filtration using a small column of Sephadex G-25 (about 1 ml volume) also at pH 8. The luciferin-bound LBP is eluted at the void volume. To measure the amount of LBP, the following assay buffer is added to a small portion of the elu-ate 0.2 M phosphate, pH 6.3, containing 0.25 mM EDTA, 0.1 mg/ml of BSA, and luciferase (Morse and Mittag, 2000). The total light obtained represents a relative amount of LBP the absolute amount (the weight or the number of molecules) cannot be obtained because the quantum yield of the luminescence reaction is not known. 

O2 generated therefore, no light emission would be expected. For the occurrence of luminescence, the SOD activity in the tissue must be distributed unevenly very low levels of SOD activity should be distributed at the sites of luminescence. 

Dendrimers are complex but well-defined chemical compounds, with a treelike structure, a high degree of order, and the possibility of containing selected chemical units in predetermined sites of their structure [4]. Dendrimer chemistry is a rapidly expanding field for both basic and applicative reasons [5]. From a topological viewpoint, dendrimers contain three different regions core, branches, and surface. Luminescent units can be incorporated in different regions of a dendritic structure and can also be noncovalently hosted in the cavities of a dendrimer or associated at the dendrimer surface as schematically shown in Fig. 1 [6]. 

Alkaline phosphatase-labeled probes are synthesized so that 18 bases are complementary to sequences on the arms of the bDNA. Three hybridization sites are located on each branch for a total binding capacity of 45 labeled probes per bDNA molecule. The alkaline phosphatase catalyzes the dephosphorylation of chemiluminescent substrate, dioxetane (Lumi-Phos Plus, Lumigen, Detroit, MI). The intensity of the light emission is measured with a plate luminometer as relative luminescent units. 

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