The early optical dynamic response, resulting population, and electronic coherence are investigated experimentally and modeled theoretically for IR144 in solution. The fluorescence and stimulated emission response are studied systematically as a function of chirp. The magnitude of the chirp effect on fluorescence and stimulated emission is found to depend quadratically on pulse energy, even whe...

We instituted a quasi-quality assurance program for demonstrating coniferyl alcohol's fluorescence and fluorescence diminishment following enzymatic oxidation. The magnitude of diminishment was a measure of catalysis. High throughput screening was performed in pseudo-kinetic and endpoint modes by measuring the fluorescence at 416 nm following excitation at 290, 310 or 340 nm. Dose-response trac...

Two-photon excitation of a trifluorophore (6-carboxyfluorescein, N,N,N',N'-tetramethyl-6-carboxyrhodamine and cyanine-5 monofunctional dye) labeled DNA, which has a scaffold of 26 nucleotides, was achieved using focused laser light of a Q-switched Nd-YAG laser (1064 nm). The observed fluorescence signature (emission ratio from the three fluorophores) of the labeled DNA after two-photon excitati...

Molecular excitation by the simultaneous absorption of two photons provides intrinsic three-dimensional resolution in laser scanning fluorescence microscopy. The excitation of fluorophores having single-photon absorption in the ultraviolet with a stream of strongly focused subpicosecond pulses of red laser light has made possible fluorescence images of living cells and other microscopic objects...

A validated HPLC method was developed to determine doxorubicin concentration in a small volume of rat plasma (60 µl) with convenient fluorescence detection. Sample preparation includes a simple one-step liquid-liquid extraction using minimum amount of organic solvent, with extraction recoveries more than 95%. The analysis was accomplished using PerfectSil C18 column maintained at 35 °C and a mo...

This paper presents a unique optical technique that utilizes the reabsorption and emission of two fluorescent dyes to accurately measure film thickness while minimizing errors caused by variations in illumination intensity and surface reflectivity. Combinations of dyes are selected that exhibit a high degree of emission reabsorption and each dye concentration is adjusted to create an optically ...

A validated HPLC method was developed to determine doxorubicin concentration in a small volume of rat plasma (60 µl) with convenient fluorescence detection. Sample preparation includes a simple one-step liquid-liquid extraction using minimum amount of organic solvent, with extraction recoveries more than 95%. The analysis was accomplished using PerfectSil C18 column maintained at 35 °C and a mo...

A new sensitive, simple and rapid method for determination of methotrexate (MTX) was developed based on quenching effects of MTX on the fluorescence intensity of Tb3+-1,10-phenanthroline complex. The fluorescence intensity was measured with excitation wavelength of 300 nm and emission wavelength of 545 nm and the quenched fluorescence intensity is proportional to the concentration of MTX in Tris...

A new in situ fluorometer for the detection of oceanic photosynthetic pigment fluorescence is described. Emission spectra from 546 to 733 nm are recorded for each of three different visible excitation bands ten times a second. A Spectralon cell is used to improve the excitation coupling to and the collection efficiency from the sample volume. Laboratory tests demonstrated that the fluorescence ...