Fluorescence wavelength

Bidimenslonal Fluorescence Wavelength Programming LC Analysis of Air Particulate Extract... 

Fig. 1 N-formyltryptophanamide used for QM calculations on a tryptophan trimmed from a protein structure, also showing the two kinds of electron density shifts that control Trp fluorescence wavelength (red) and intensity/lifetime (green)...

Experiment [80], however, requires that the red-shifted fluorescence comes from molecules that are in an environment quite different from the average, behaving as if in a nonpolar environment (long wavelength, long lifetime). The red-shifted component, therefore, appears to be from chromophores that are embedded more deeply into the membrane. In the case of Aladan, the absorption and fluorescence wavelengths are both longer in the more water-exposed protein sites, but the lifetime is shorter in water [53]. 

The first, and still the most commonly used, of the tunable lasers were those based upon solutions of organic dyes. The first dye laser was developed by Sorokin and Lankard 05), and used a "chloro-aluminum phthalocyanine" (sic) solution. Tunable dye lasers operating throughout the visible spectrum were soon produced, using dyes such as coumarins, fluorescein, rhodamines, etc. Each dye will emit laser radiation which is continuously tunable over approximately the fluorescence wavelength range of the dye. 

Fluorophores can be visualized in fluorescence microscopy using special filter blocks that are composed of the excitation filter, dichroic mirror and emission filter. The excitation filter must select wavelengths of light from a light source that fall in the maximum absorption region of the fluorophore. The emission filter must pass the fluorescent wavelengths but not the excitation wavelengths. The dichroic mirror... 

Emission filter must pass the fluorescent wavelengths but not the excitation wavelengths. 

Figure 8.8. Examples of nonexponential fluorescence decay curves 9,10-diphenyl-anthracene on alumina for chromatographic purposes (Uhl.Oelkrug, unpublished results) (unnumbered curves time profiles of the excitation pulse, 2 - 360 nm). Upper left effect of environment (1) high vacuum, (2) liquid n-hexane. c=3/tmol g"1,2 =440 nm. Upper right effect of fluorescence wavelength (1) 2 = 500 nm, (2) 440 nm, (3) 406 nm c=3 /tmol g 1. Lower left effect of surface loading (1) 3 /rmol g (2) 0.13 mol g , (3) 0.02/r mol g"1 2e=440. Lower right effect of sample thickness (l) d - . (2) d - 0 c - 3 /tmol g 1, 2 = 440 nm.

Fi gure 8.20. Fluorescence reabsorption in a semi-infinite scattering layer. Ordinate fraction of emitted to true fluorescence intensity. Abscissa diffuse reflectance at the fluorescence wavelength. Parameter diffuse reflectance at the absorption wavelength, The scattering coefficient is assumed to be independent of A (S° = S ). 

Figure 8.22. Fluorescence reabsorption in a finite scattering layer with K°/S = 0.1 as a function of the scattering thickness Sd. Ordinate fraction of emitted to true fluorescence intensity in backward (upper) and forward direction (lower). Parameter reduced absorption coefficient at the fluorescence wavelength.

K. T. V. Grattan, R. K. Selli, and A. W. Palmer, Ruby fluorescence wavelength division fiber-optic temperature sensor, Rev. Sei. Instrum. 57, 1231-1234 (1987). 

Low transit-time dispersion with photon wavelength, i.e., < 0.5 psec/nm. This minimizes the effect on convolution of the difference between the excitation and fluorescence wavelengths. Both side-window and linear focused photomultipliers satisfy this. 

Problems still remain in overcoming the intrinsic optical cross-talk in arrays of avalanche photodiodes, which at present precludes equivalent applications to multianode MCP-PMs in such as multiplexed lifetime measurements at different fluorescence wavelengths. 

The protein analyzer tests response linearity (absorbance/fluorescence), wavelength accuracy and UV linearity, dynamic noise, drift, and the zero offset. 

Figure 4. FOCS fluorescence wavelength sigial during curing of Hercules 3501-6 laminate.

Two-photon excitation can be used for the fluorescence up-conversion microscope, and high axial resolution was achieved without a pinhole in this case. Figure 3.5 shows the up-converted fluorescence from a coumarin 522B solution at a fluorescence wavelength of 520 nm observed in the same manner of Figure 3.4d without pinhole. In this measurement, a fundamental laser pulse at 800 nm was used for excitation. The axial resolution with two-photon excitation was evaluated to be 0.97 pm (FWHM) by fitting for the first derivative of the obtained data. This result indicates... 

ESA and stimulated emission cross sections at the fluorescence wavelength Af. Note that ESA spectra strongly overlap the entire fluorescence region of 3 and 11 (Eig. 11, curves V, 2 ). 

Fig, 2. Left and right parts show the fluorescence dynamics of C522 in water and in p-cyclodextrin aqueous solution for the fluorescence wavelengths of 500 (squares), 520 (circles), and 540 (triangles) nm, respectively. The experimental and simulation data are scatter and line, respectively. 

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