Search results for "Fluorescence"

In vitro preliminary study of osteoblast response to surface roughness of titanium discs and topical application of melatonin

2014

Objectives: To observe human osteoblast behavior cultured in vitro on titanium discs (Ti) in relation to surface roughness and melatonin application. Study Design: Human osteoblasts (MG-63) were cultured on 60 Ti6Al4V discs divided into three groups: Group I: discs treated with dual acid etching; Group II dual acid etching and blasting with calcium phosphate particles; Group III (control) machined discs. Surface roughness and topography of the discs were examined with scanning electron microscope (SEM) and confocal laser scanning electron microscope( CLSM). Osteoblast adhesion, proliferation and cell morphology were determined by means of fluorescence microscopy with Image-Pro Plus software…

Photochemical synthesis of pyrene perfluoroalkyl derivatives and their embedding in a polymethylmethacrylate matrix: a spectroscopic and structural s…

2014

A photochemical, alternative and eco-compatible approach to perfluoroalkyl derivatives of pyrene is presented. The perfluoroalkyl chain is regiospecifically introduced at the 1 position of pyrene. The synthesized products have been embedded in a polymethylmethacrylate matrix by photocuring at 365 nm. Both the photochemical reactions can be considered a “green tool” for the synthetic chemist in order to obtain materials with prospective optoelectronic applications. The so-obtained composites have been the object of a study by UV and fluorescence spectroscopy in order to explore their luminescence properties. The small angle X-ray scattering and the transmission electron microscopy techniques…

Laser-Fabricated Fluorescent, Ligand-Free Silicon Nanoparticles: Scale-up, Biosafety, and 3D Live Imaging of Zebrafish under Development

2022

This work rationalizes the scalable synthesis of ultrasmall, ligand-free silicon nanomaterials via liquid-phase pulsed laser ablation process using picosecond pulses at ultraviolet wavelengths. Results showed that the irradiation time drives hydrodynamic NP size. Isolated, monodisperse Si-NPs are obtained at high yield (72%) using post-treatment process. The obtained Si-NPs have an average size of 10 nm (not aggregated) and display photoemission in the green spectral range. We directly characterized the ligand-free Si-NPs in a vertebrate animal (zebrafish) and assessed their toxicity during the development. In vivo assay revealed that Si-NPs are found inside in all the early life stages of …

Structure-property relationships in aromatic thioethers featuring aggregation-induced emission : Solid-state structures and theoretical analysis

2019

We describe in this paper a structure–property relationship study of aromatic thioethers with aggregation-induced emission (AIE) properties. We combine a structural analysis based on geometrical consideration with an in-depth analysis of the crystalline packing supported by quantum mechanical calculations. Our results allow us to correlate the enhanced fluorescence quantum yields with the significant increase of C–H⋯π and the decrease of π⋯π interactions in the solid state – a result which supports the well-accepted AIE mechanism quantitatively.

Two-photon absorption dye based on 2,5-bis(phenylacrylonitrile)thiophene with aggregration enhanced fluorescence

2016

This paper reports the synthesis and characterization of a 2,5-bis(phenylacrylonitrile) thiophene based two-photon dye, designed to show enhancement in fluorescence quantum yield in nanoaggregated form. Strong solvatochromism has been observed and explained by the favoritism of locally excited (LE) or internal charge transfer (ICT) state depending on the solvent polarity. Aqueous dispersions of nanoparticles have been prepared and investigated regarding their optical properties which were correlated to the LE and ICT state and the molecular structure of the aggregates. (C) 2016 Optical Society of America

Determination of cobalt in foods by atomic absorption and inductively coupled plasma spectrometry (Short communication)

1988

Back Cover: Nanographenes: Ultrastable, Switchable, and Bright Probes for Super‐Resolution Microscopy (Angew. Chem. Int. Ed. 1/2020)

2019

Biosilica electrically-insulating layers by soft lithography-assisted biomineralisation with recombinant silicatein.

2011

Specific orientation of dipole moments in azocrown cetocyanine dyes determined by electrooptical absorption measurements (EOAM)

2019

Abstract From electrooptical absorption measurements (EOAM) follows that the dipole moments of azacrown ketocyanine dyes 2,5-di{(E)-1-[4-(4,7,10,13-tetraoxa-1-azacyclopentadecyl)phenyl]methylidene}-1-cyclopentanone (Compound 1) and (E)-1-(2-hydroxy-4methoxyphenyl)-3-[4-(4,7,10,13-tetraoxa-1-azacyclopentadecyl)phenyl]-2-propen-1-one (Compound 2) in the equilibrium ground state μg and the change of dipole moments upon transition to the excited Franck–Condon state Δaμ are large. This alteration causes a significant long-wavelength shift of the absorption and emission spectra, as well as large fluorescence Stokes shift with increasing polarity of the solvent. From the DFT calculations follows t…

Oscillator strengths of sulphur 3s23p34s3So-3s23p34p3P transitions measured by time resolved two-photon laser spectroscopy

1997

Oscillator strengths for the three 3s23p34s 3S1o-3s23p34p 3P0,1,2 transitions in neutral sulphur have been determined directly from lifetime measurements. Two-photon UV laser excitation and subsequent fluorescence detection have been used on atoms produced in a thermal sulphur beam or in a laser-driven plasma. A good agreement was found between data obtained in both schemes. The lifetime data obtained, τ(3P0) = 46.1(1.0) ns, τ(3P1) = 46.1(1.0) ns and τ(3P2) = 46.1(1.0) ns are compared with results of theoretical and experimental data from literature. The absorption oscillator strengths derived are f(3S1o-3P0) = 0.120(0.003), f(3S1o-3P1) = 0.360(0.008) and f(3S1o-3P2) = 0.600(0.013), respect…