Dipicolinic acid (DPA) and the Ca2+ complex of DPA (CaDPA) are major chemical components of bacterial spores. With fluorescence being considered for the detection and identification of spores, it is important to understand the optical properties of the major components of the spores. We report in some detail on the room-temperature fluorescence excitation and emission spectra of DPA and its cal...

In conventional microscopes, fluorescence emission is separated from the backscattered illumination using the Stokes shift, whereby the emission occurs at a longer wavelength to the excitation. Such separation is usually achieved through a combination of wavelength filters that divide the spectrum into mutually exclusive excitation and emission bands. It is therefore impossible in these microsc...

BACKGROUND AND OBJECTIVE The objective of this study was to explore whether fluorescence spectroscopy signatures differed between normal variations within the ovary, benign neoplasms, and ovarian cancer. STUDY DESIGN/MATERIALS AND METHODS Ovarian tissue fluorescence emission spectra were collected sequentially at 18 excitation wavelengths ranging from 330 to 500 nm from 11 patients undergoing...

OBJECTIVE The objective of this study was to compare the effects of chemopreventive agents on natural fluorescence emission of ovarian cells in a cell culture and in a primate model as a feasibility trial to monitor drug activity. METHODS Fluorescence emission spectra were collected from normal (NOE) and immortalized ovarian surface epithelial cells at 290, 360, and 450 nm excitation. Redox p...

There is no satisfactory mechanism to detect premalignant lesions in the upper aero-digestive tract. Fluorescence spectroscopy has potential to bridge the gap between clinical examination and invasive biopsy; however, optimal excitation wavelengths have not yet been determined. The goals of this study were to determine optimal excitation-emission wavelength combinations to discriminate normal a...

In this paper, the fluorescence behaviour of nano colloids of ZnO has been studied as a function of the excitation wavelength. We have found that excitation at the tail of the absorption band gives rise to an emission that shifts with the change of the excitation wavelength. The excitation wavelength dependent shift of the fluorescence maximum is measured to be between 60 and 100 nm. This kind ...

Fluorescence spectroscopy has been demonstrated to be a powerful tool for characterizing phytoplankton communities in marine environments. Using different fluorescence spectra techniques, it is now possible to discriminate the major phytoplankton groups. However, most of the current techniques are based on fluorescence excitation measurements, which require stimulation at different wavelengths ...

A novel and simple method to prepare well dispersed single-walled carbon nanotubes with strong visible fluorescence in water is reported. The visible fluorescence was found to be responsive to pH value and metal ions, and tunable emission ability of oxidized SWCNTs depending on the excitation wavelength and a novel self-excitation and emission process were found.

The effect of excitation and emission wavelengths on fluorescence decay times of Chlorophyll a were measured in four solutions (C approximately 10(-5) mol X 1(-1] and in polymethyl methacrylate films. The decay times observed were corrected with respect to self-absorption and re-emission effects. The fluorescence decay times of Chlorophyll a was found to depend on both the excitation and the em...