Fluorescence brightness

Fig. 17 Cadmium selenide QDs, dissolved in toluene, fluorescing brightly in the presence of a ultraviolet lamp, in three noticeably different colors (blue 481 nm, green 520 nm, and orange 612 nm). The blue QDs have the smallest particle size, the green dots are slightly larger, and the orange dots are the largest. (Adapted from http //www. amazingrust.com/ experiments/current proj ects / Misc.html)...

FIG. 3. Confocal images showing the location of the SR in live myocytes within an intact, small diameter (< 250 nm passive diameter), pressurized (70 mmHg) artery from the rat mesenteric artery arcade. The artery was loaded with Fluo-4 as the membrane-permeant acetoxymethyl ester. Some of this high-affinity, Ca2+ indicator dye is often sequestered in the SR (cf. Goldman et al 1990). The SR can then be readily visualized, especially when [Ca2+]CYx is low (as in the panels at 0 and 6.8 s), because the intra-SR dye is saturated with Ca2+, and fluoresces brightly. This artery was treated with 1.0 fim phenylephrine (PE), which caused the [Ca2+]CYT level to oscillate asynchronously in the cells seen in the centre of the panel. The cell outlines are clearly visible when [Ca2+]CYT tiscs, as in the panels at 3.4 and 10.2 s. Note that nearly all of the SR (the very bright areas, especially in the 0 and 3.4 s panels) lies parallel to, and immediately beneath the PL (from Miriel at al 1999, with permission). 

TIRF is easy to set up on a conventional upright or inverted microscope with a laser light source or, in a special configuration, with a conventional arc source. TIRF is completely compatible with standard epi-fluorescence, bright-field, dark-field, or phase contrast illumination so that these methods of illumination can be switched back and forth readily. Some practical optical arrangements for observing TIRF through a microscope are described in Section 7.4. 

Several anthraquinone-type dyes and their by-products, a fluorescent bright-ener, and a by-product of polyester production, as well as anionic and nonionic surfactants and their degradation products, could be identified in this sample. 

Fig. 11.10. When lacZ has been transfected into Drosophila embryos in association with a neuronal-cell-specific promoter, the cells that fluoresce brightly in the presence of fluorogenic /i-galactosidase substrate will, when sorted, develop neuronal processes in culture. From Krasnow et al. (1991). Science 251 81-85. Copyright AAAS.

Probe Probe is a general term used, in flow cytometry, to refer to any chemical that fluoresces when it reacts or complexes with a specific class of molecules and therefore can be used to assay that molecule quantitatively. Propidium iodide and acridine orange are probes for nucleic acid because they complex specifically with nucleic acids and fluoresce brightly when they have... 

Combinatorial polymer synthesis in combination with HTS is suitable for the fast qualitative detection of new compounds showing specifications of light-emitting diodes as the fluorescence brightness and film-forming properties can be checked simultaneously. 

Randolph, J.B. and Waggoner, A.S. (1997) Stability, specificity and fluorescence brightness of multiply-labelled fluorescent DNA probes. Nucleic Acids Res 25 2923-9. 

Fig. 8.1. Three major categories of molecular dynamic processes or reactions that can be analyzed by FCS. (a) Reactions that lead to a significant [15] change in the translational diffusion coefficient of the fluorescent reaction partner, (b) Molecular dynamic processes or reactions that change the fluorescence brightness of the studied molecules, (c) Spectral cross-correlation [16], e.g., of reaction partners labeled with green (G) and red (R) emitting fluorophores that upon association move in concert and generate correlated fluctuations in the green and red emission range...

The reaction needs to change the fluorescence quantum 3ueld or the excitation cross-section of the reactants (Fig. 8.1b). Thereby, the magnitude of the fluorescence emission per molecule is changed, reflected by the fluorescence brightness coefficient Q of (8.1). 

Alternatively, in the absence of a significant change in neither diffusion properties nor fluorescence brightness as a consequence of the reaction taking place, various cross-correlation approaches can be applied (Fig. 8.1c). For this purpose, cross-correlation FCS has been introduced correlating different detection channels, separated with respect to emission wavelength range [16] or spatial localization of the observation volume [18]. 

Here, Qi is the fluorescence brightness coefficient of state i and Xij(r) is the solution to the following set of differential equations and initial conditions ... 

A,B Cephaeliue (R,. - 0.2) and emetine (R, 0.4) are the major alkaloids, which fluoresce light blue in UV-36.Snm without chemical treatment. With iodine reagent cephaeliue fluoresces bright blue and emetine yellow-white in UV-365nm and they turn red and weak yellow, respectively, in vis. (—> B). Minor alkaloids, e.g. 0-methylpsychotrine, are found in R, range of emetine, or psychotrine in the R, range of cephaeline. 

Note, Cascarosides A-C also fluoresce bright yellow when treated with the KOH reagent. 

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