Particles with the size of 1-100 nm are known as nanoparticles (NPs). The widespread use of silver NPs (AgNPs) makes it familiar in different industries. They have unique properties as a result of their high surface to volume ratio, although aggregation of NPs interferes with their functions. This phenomenon has several side effects on the environment, the amount of which may depend on t...

Objective(s):Cefixime (Cfx), is a semi-synthetic third-generation oral cephalosporin antibiotic that is prescribed for the treatment of susceptible infections. There are some procedures for the determination of Cfx in pharmaceutical formulations and biological samples. Herein a spectrofluorimetric method was proposed for Cfx determination based on the fluorescence quenching of terbium-danofloxa...

Fluorescence imaging has been demonstrated to be able to detect and diagnose different tumour types in a range of biological tissues including cervix, lung, and along the gastrointestinal tract. An approach based on laser induced tissue autofluorescence may be applied minimally invasively using endoscopes, although there is a high degree of overlap in endogenous fluorophore excitation/emission ...

a flow injection system is reported for the determination of fluoride based on its effects on the fluorescence intensity of al-morin complex at ph 3.0 in ethanol-warn mixture. the effect of important parameters such as excitation and emission wavelengths, ph, reagents concenkations, flow rate of the carrier stream, sample injection volume, time of measurepent and interferences are reported. cat...

Organic dyes offer unique properties for their application as room temperature single photon emitters. By means of photon-correlation, the emission characteristics macrocyclic para-xylylene linked perylene bisimide (PBI) trimers and tetramers dispersed in polymethyl methacrylate matrices are analyzed. The optical data indicate that, despite strong enhancement PBI according to larger number chro...

Single-molecule fluorescence imaging is at the forefront of tools applied to study biomolecular dynamics both in vitro and in vivo. The ability of the single-molecule fluorescence microscope to conduct simultaneous multi-color excitation and detection is a key experimental feature that is under continuous development. In this paper, we describe in detail the design and the construction of a sop...

In green-sulfur bacteria sunlight is absorbed by antenna structures termed chlorosomes, and transferred to the RC via the Fenna-Matthews-Olson (FMO) complex. FMO consists of three monomers arranged in C3 symmetry where each monomer accommodates eight Bacteriochlorophyll a (BChl a) molecules. It was the first pigment-protein complex for which the structure has been determined with high resolutio...

We describe the design, properties, and performance of an excitation-emission (EE) fluorimeter that enables spectral characterization of an object simultaneously with respect to both its excitation and its emission properties. Such devices require two wavelength-selecting elements, one in the optical path of the excitation broadband light to obtain tunable excitation and the other to analyze th...

We report the study of femtosecond laser-induced air plasma fluorescence under the illumination of terahertz (THz) pulses. Semiclassical modeling and experimental verification indicate that time-resolved THz radiation-enhanced emission of fluorescence is dominated by the electron kinetics and the electron-impact excitation of gas molecules or ions. We demonstrate that the temporal waveform of t...

Controlling two-photon molecular fluorescence leading to selective fluorophore excitation has been a long sought after goal in fluorescence microscopy. In this letter, we thoroughly explore selective fluorescence suppression through simultaneous two-photon absorption by two different fluorophores followed by selective one-photon stimulated emission for one particular fluorophore. We achieve thi...