Two-photon fluorescence (TPF) is one of the most important discoveries for biological imaging. Although a cw laser is known to excite TPF, its application in TPF imaging has been very limited due to the perceived low efficiency of excitation. Here we directly excited fluorophores with an IR cw laser used for optical trapping and achieved single-molecule fluorescence sensitivity: discrete stepwi...

A setup consisting on a laser scanning microscope (LSM 410, Zeiss, Germany) equipped with appropriate detection units was developed for time-resolved intracellular fluorescence spectroscopy and fluorescence lifetime imaging (FLIM) for on-line detection of structural changes of various biomolecules. Short-pulsed excitation was performed with a diode laser which emits pulses at 398 nm with 70 ps ...

Microdroplets generated inside microfluidic devices have been widely used as miniaturized chemical and biological reactors allowing important reductions in experimental fluid volumes and making it possible to carry out high-throughput assays. Laser-induced fluorescence (LIF) is commonly used to detect and quantify the product, marker or cell content inside each individual droplet. In this work,...

A two-laser technique is used to study laser-particle interactions and the disintegration of soot by high-power UV light. Two separate 20 ns laser pulses irradiate combustion-generated soot nanoparticles with 193 nm photons. The first laser pulse, from 0 to 14.7 J/cm2, photofragments the soot particles and electronically excites the liberated carbon atoms. The second laser pulse, held constant ...

PURPOSE Because of the potential usefulness of evaluating and treating choroidal neovascularization obscured by blood, we designed this study to quantify the transmission of dye fluorescence and laser energy through blood. METHODS Blood preparations anticoagulated with ethylenediaminetetraacetic acid with hematocrits of 0% (plasma), 46%, and 99% were placed in open cuvettes with path lengths ...

Copyright © 1995 by J. Coppeta. Published by the American Institute of Aeronautics and Astronautics, Inc. with permission. Abstract In this paper a method of quantifying fluid mixing using the fluorescence intensity of fluorophors in aqueous solution is presented. The general technique involves ratioing optically separable fluorescence from two fluorescent dyes. The resulting ratio normalizes ...

The cyanonitrene radical, NCN, is detected by laser-induced fluorescence in laminar, adiabatic, flat phi=1.3 methane-air flames at 200 hPa and atmospheric pressure. Laser excitation of the A approximately 3Piu(020)-X approximately 3Sigmag-(000) band at 317 nm allows off-resonant fluorescence to be detected at 326 nm. Excitation and dispersed fluorescence spectra are presented, as well as profil...

The recent development of the dye laser [1] 1 has opened up an important new field of applications for organic dyes. This has led to a renewed interest in the theory of nonradiative transitions in dyes and also to the synthesis of new highly fluores cent dyes. In this article we review briefly the relations between fluor· escence and molecular structure in the most important classes of laser dy...

OBJECTIVES The aim of this study was to evaluate the performance of a visual-tactile examination and a laser fluorescence device for detecting residual dentinal caries after carious dentin removal with bur excavation, hand excavation and chemomechanical excavation (Carisolv()]. METHODS Thirty extracted coronal caries primary second molars were used. The caries infected dentin has been removed...