PURPOSE The goal of this study is the characterization of the strong yellow fluorescence of oxidized melanin in the retinal pigment epithelium (RPE) and the choroid. METHODS Naturally occurring melanin in the human retina and choroid was oxidized by exposing fixed and plastic-embedded sections of a human eye to light and hydrogen peroxide. Synthetic melanin was also oxidized in vitro by expos...

Three new carboxylic-acid substituted oligo-phenylenevinylenes (OPVs) with electron-donating substituents in the central ring were synthesized in high yield by the Mizoroki–Heck reaction. The linkers were optically characterized by UV–vis absorption spectrophotometry, fluorescence spectroscopy in solution and the solid state, and measurement of the emission quantum yield. A comparison of substi...

High enhancement of fluorescence emission, improved fluorophore photostability, and significant reduction of fluorescence lifetimes have been obtained from high aspect ratio (>100) silver (Ag) nanowires. These quantities are found to depend on the surface loading of Ag nanowires on glass slides, where the enhancement of fluorescence emission increases with the density of nanowires. The surface ...

Fluorescence emission and excitation spectra were measured over a 7-day period for Bacillus subtilis (Bs), a spore-forming, and Staphylococcus aureus (Sa), a nonspore-forming bacteria subjected to conditions of starvation. Initially, the Bs fluorescence was predominantly due to the amino acid tryptophan. Later, a fluorescence band with an emission peak at 410 nm and excitation peak at 345 m, fr...

Stimuli-responsive luminescent materials, which are dependent on changes in physical molecular packing modes, have attracted more and more interest over the past ten years. In this study, 2,2-dihydroxy-1,1-naphthalazine was synthesized and shown to exhibit different fluorescence emission in solution and solid states with characteristic aggregation-induced emission (AIE) properties. A remarkable...

9-Anthryl-oligothiophenes (9A-T., n= l-4) have been studied in n-hexane solution between helium and room temperature using absorption, fluorescence emission and excitation spectra and time resolved fluorescence measurements. These compounds are reference systems for studies on intramolecular energy and charge transfer in donor/acceptor-substituted conjugated chain molecules. The absorption spec...

We recently described a series of genetically encoded, single-fluorophore-based sensors, termed AmTrac and MepTrac, which monitor membrane transporter activity in vivo (De Michele et al., 2013). However, being intensiometric, AmTrac and Meptrac are limited in their use for quantitative studies. Here, we characterized the photophysical properties (steady-state and time-resolved fluorescence spec...

Investigation done on Y2SiO5 nanoparticles doped with Eu 3+ ions obtained with the alkoxy sol-gel route is presented in this paper. We investigate the optical and thermal properties of obtained material during the conversion of the gel into nanocrystalline form. Fourier transform infrared spectroscopy and fluorescence spectroscopy of Eu ions are used for the optical characterizations, while the...

A new approach to time-resolved fluorescence spectroscopy based on stimulated emission depletion (STED) of two-photon excited states is presented. Combined with time-resolved detection, STED can circumvent orientational averaging constraints and spontaneous emission selection rules inherent in all conventional techniques. Applications of STED to the study of molecular probe dynamics are present...

A krypton-fluorine excimer laser at a 248-nm wavelength was used to irradiate normal and severely atherosclerotic segments of human postmortem femoral arteries. Single pulses and multiple pulses required for penetration or perforation of the arterial wall were applied with 16 nsec pulse width and 5 J/cm2/pulse energy fluence. The total fluorescence of irradiated and ablated tissue was analyzed ...