One of the conventionally accepted requirements for parallel factor analysis (PARAFAC) to handle the fluorescence excitation emission matrices (EEMs) is the independence of each component's absorption and emission spectra in simple mixtures of fluorophores. EEMs of samples in which Förster resonance energy transfer (FRET) occurs between fluorophores seem to fail to meet this requirement. A rigo...

1.1 Fluorescence phenomenon The absorption and subsequent emission of light by organic and inorganic specimens is typically the result of physical phenomena known as luminescence, which occurs at electronically excited states. Luminescence is formally divided into two categories: fluorescence and phosphorescence, depending on the nature of the excited state. Fluorescence occurs when a photon ex...

An analytical method is described for the simultaneous quantitation of polycyclic aromatic hydrocarbons pAHs] and alkylderivatives [alkyl-PAHs] in "real world" samples using microbore reversed-phase high performance liquid chromatography in conjunction with two programmable fluorescence detectors. Sensitivity and selectivity were enhanced by analyzing PAHs under their optimum fluorescence wavel...

Highly resolved emission and one-photon fluorescence excitation spectra for 1,4-diphenyl-1,3-butadiene seeded in a supersonic expansion of helium have been measured. The spectra show a long-lived (52.8 nsec for excitation at the 0-0) state at 29,652.5 cm(-1), approximately 1,150 cm(-1) below the well-characterized (1)B(u) state, which is assigned as (1)A(g)-i.e., we have directly observed a pol...

PURPOSE To characterize the intrinsic fluorescence (autofluorescence) of the human ocular fundus with regard to its excitation and emission spectra, age relationship, retinal location, and topography, and to identify the dominant fluorophore among the fundus layers. METHODS Using a novel fundus spectrophotometer, fluorescence measurements were made at 7 degrees temporal to the fovea and at th...

We present computationally efficient and accurate semiempirical models of light transfer for real-time analysis of multilayer fluorescing media exposed to normally incident excitation light. The model accounts for absorption and strong forward scattering as well as for internal reflection at the interface between the medium and the surrounding air. The absorption and scattering coefficients are...

europium (eu) doped zno microsphere based nano-sheets were synthesized through hydrothermal method. effects of different concentrations of europium on structural and optical properties of zno nano-sheets were investigated in detail. prepared un-doped and eu-doped zno samples were characterized using x-ray diffraction (xrd), energy dispersive x-ray spectroscopy (edx), scanning electron microscop...

Excitation-emission matrix spectroscopy (EEMS) was used to characterize the ultra violet fluorescence fingerprints of eight crude oils (with a 14,470-fold range of dynamic viscosity) in seawater. When the chemical dispersant Corexit 9500 was mixed with the oils prior to their dispersion in seawater, the fingerprints of each oil changed primarily as an increase in fluorescence over an emission b...

Antibody-conjugated fluorospheres (ACF) were used to phenotype murine leukocytes by flow cytometric analysis. Multicolor immunofluoresence (beyond simultaneous 4-color analysis) is limited by the availability of specific antibody-fluorochrome chrome conjugates and even further restricted by the spectral emission overlap of many of the fluorochromes when used in combination. Fluorospheres posses...

The differentiation of porcelain from tooh using fluorescence emission was investigated as a basic research for the visual detection of porcelain-restored teeth in mass dental health examinations. The fluorescence spectra were taken from the extracted human maxillary central incisors and five types of porcelain by excitation using the light 380-470 nm. There was a clear difference in fluorescen...