Earlier steady-state fluorescence studies showed that 2-butylamino-6-methyl-4-nitropyridine N-oxide (2B6M) can undergo fast excited-state intramolecular proton transfer (ESIPT). In a nonpolar solvent such as n-octane, both normal and tautomeric fluorescence was observed. Strikingly, the relative ratio of those two emission bands and the fluorescence quantum yield of the normal emission were fou...

Treatment of chicken blood smears and semithin sections from Epon-embedded mouse tissues with aqueous solutions of the 3-aminonaphthalimides FA-142, FA-2043, and FA-2143 induced a strong green-yellow fluorescence of chromatin under violet or violet-blue excitation. Chromatin emission was abolished by previous DNase or hot TCA treatment. The use of 3-methoxy (FA-655) and 3-nitro derivatives (M-4...

BACKGROUND Cotton is an important domesticated fiber used to manufacture a variety of products and industrial goods. During harvesting with cotton strippers and cotton pickers, it is contaminated with foreign matter from botanical and non-botanical sources which adversely affect the quality and consistency of cotton, and therefore reduces its market value. To improve the current grading done by...

We show that resonance fluorescence, i.e., the resonant emission of a coherently driven two-level system, can be realized with a semiconductor quantum dot. The dot is embedded in a planar optical microcavity and excited in a waveguide mode so as to discriminate its emission from residual laser scattering. The transition from the weak to the strong excitation regime is characterized by the emerg...

The tryptophans in the gramicidin channel play a crucial role in the organization and function of the channel. The localization and dynamics of these tryptophans have been studied using fluorescence spectroscopy, especially utilizing environment-induced effects on the rates of solvent relaxation around these residues in membranes. When incorporated into model membranes of dioleoyl-sn-glycero-3-...

We have developed a multiplex fluorophore molecular beacon () with fluorophores located at its end to produce unique FRET (Fluorescence Resonance Energy Transfer). It exhibited diverse fluorescence properties depending on the mixing pattern, such as large Stokes shift emission and multiple colors, namely, blue, green and red using one excitation wavelength. Our also worked in probing a target p...

The use of absorption and fluorescence spectroscopy for following the progress of the photoreaction between DNA and 4-aminomethyl-4,5‘,8-trimethylpsoralen (AMT) has been investigated. Absorption at long wavelengths and fluorescence both decline upon intercalation of AMT into the DNA helix. The loss of fluorescence from AMT and the accompanying appearance of monoadduct fluorescence upon irradiat...

The potential of effluent DOM to undergo microbial degradation was assessed in batch experiments. Effluent samples from Haifa wastewater treatment plant and Qishon reservoir (Greater Haifa wastewater reclamation complex, Israel) were incubated either with effluent or soil microorganisms for a period of 2-4 months and were characterized by dissolved organic carbon contents (DOC), UV(254) absorba...

Adsorption of polymers onto particles has been a subject of study because of its importance in the behavior of suspensions.1,2 To understand the adsorption/desorption process in detail, studies have been carried out with model systems. Some studies have employed polystyrene (PS) adsorbed onto metals, silica, glass, and mica.3-7 In previous work, we reported on the use of pyrene-labeled PS to st...