During the development of neoplasia, epithelial tissues undergo biochemical and structural changes that can manifest in tissue fluorescence. There have been several reports on different in vivo fluorescence characteristics between normal and precancerous (dysplastic) tissues. However, it has been difficult to identify and quantify the origins of these changes, mainly because of distortions intr...

There is a growing need for cellular imaging with fluorescent probes that emit at longer wavelengths to minimize the effects of absorption, autofluorescence, and scattering from biological tissue. In this paper a series of new environmentally sensitive hemicyanine dyes featuring amino(oligo)thiophene donors have been synthesized via aldol condensation between a 4-methylpyridinium salt and vario...

We investigated the electronic properties of N(5)-ethyl flavinium perchlorate (Et-Fl(+)) and compared them to those of its parent compound, 3-methyllumiflavin (Fl). Absorption and fluorescence spectra of Fl and Et-Fl(+) exhibit similar spectral features, but the absorption energy of Et-Fl(+) is substantially lower than that of Fl. We calculated the absorption signatures of Fl and Et-Fl(+) using...

X-ray fluorescence spectroscopy is a widely used method for determining the electronic configuration and local structure of dilute species with high sensitivity. In the dilute limit, and for thin films, the X-ray fluorescence signal is directly proportional to the atomic sub-shell absorption coefficient. However, for concentrated samples, the well-documented self-absorption effect often leads t...

It is shown by sedimentation velocity and polarization of fluorescence measurements that yeast enolase in solution becomes more compact on addition of magnesium. This is associated with changes in absorption, fluorescence emission, and fluorescence-polarization spectra, as well as in the thermal stability of the enzyme. Evidence is presented that this structural change is produced by the bindin...

Various chemicals used for photodynamic therapy, a promising treatment for cancer, exhibit high fluorescence yields, which can be used for tumour detection. For a chosen few such compounds fluorescence lifetimes, absorption, and steady state fluorescence spectra were measured at different concentrations (ranging from 10 M to 10 M) in a variety of solvents. The lifetimes were repeated at three d...

human serum albumin (hsa) is an abundant, multifunctional and nonglycosylated negatively charged plasma protein. hsa ascribed ligand-binding and transport properties, antioxidant functions and enzymatic activities. in the present study, the interaction and side effects of a new designed anti-cancer compound (1,10-phenanthroline butyl dithiocarbamato palladium(ii) nitrate) on hsa have been inves...

function. This application of fluorescence is based on the fact that fluorescence spectra, absorption spectra, and polarization of fluorescence are rather sensitive indicators of the local environment of the chromophore. Therefore, fluorescence measurements can provide information about the environment of natural chromophores (e.g., tyrosine) or of chromophores added to the preparation (fluores...

The absorption and fluorescence spectra of 3-aminobenzo-1,2,4-triazine di-N-oxide (tirapazamine) have been recorded and exhibit a dependence on solvent that correlates with the Dimroth ET30 parameter. Time-dependent density functional theory calculations reveal that the transition of tirapazamine in the visible region is pi-->pi* in nature. The fluorescence lifetime is 98+/-2 ps in water. The f...