Search results for "Fluorescence"
showing 10 items of 2463 documents
Use of DIAGNOdent and VistaProof in diagnostic of Pre-Cavitated Caries Lesions—A Systematic Review and Meta-Analysis
2019
Objective: To analyse the published evidence of the validity of DIAGNDOdent and VistaProof in diagnosing carious depths in pre-cavitated lesions. Material and methods: A systematic review was carried out after identifying a total of 184 articles, including 27 concerning the qualitative review and a subsequent meta-analysis. The quality of the studies was evaluated by using the QUADAS-2 tool. Results: For DIAGNOdent, the sensitivity value was 0.77, the specificity value was 0.75 and AUC was 0.81 for the global meta-analyses. In relation to subgroups, the values estimated 0.85, 0.76 and 0.86, respectively, for the in vivo group and 0.71, 0.75 and 0.83 for the in vitro group. For VistaProof, s…
Retracted Article: Differential detection and quantification of cyclic AMP and other adenosine phosphates in live cells
2017
A new naphthol-based rhodamine derivative (NpRD) has been developed for the selective and differential detection of adenosine 3′,5′-cyclic monophosphate (cAMP) and adenosine phosphates (APs) (ATP, ADP, and AMP) from other nucleotides. The simple detection and quantification of cAMP in human blood cells and in other samples based on the ‘turn on’ fluorescence properties of this chemosensor through colorimetry or fluorometry makes it unique for probable application in high throughput screening.
Supramolecular complexes formed by dimethoxypillar[5]arenes and imidazolium salts: A joint experimental and computational investigation
2017
To gain more insights into the factors acting on the stability of complexes formed by pillar[5]arenes, we investigated the interaction of dimethoxypillar[5]arene with some 1-(n-alkyl)-3-(9-anthracenylmethyl)-imidazolium based organic salts. In particular, we used salts differing in not only the anion nature ([Cl−], [BF4−], [NTf2−] and [SbF6−]) and alkyl chain length (butyl, octyl and dodecylimidazolium derivatives), but also the presence of a hydrogenated or fluorinated tail (octyl and perfluorooctylimidazolium derivatives). Host–guest systems were analysed in solution, solid state and gas phase, using a combined approach of different techniques like fluorescence, 1H NMR, ESI-MS, DSC and DF…
Spectroscopy and Coordination Chemistry of a New Bisnaphthalene−Bisphenanthroline Ligand Displaying a Sensing Ability for Metal Cations
2005
A new fluorescent macrocyclic structure (L1) bearing two naphthalene units at both ends of a cyclic polyaminic chain containing two phenanthroline units was investigated with potentiometric and fluorescence (steady-state and time-resolved) techniques. The fluorescence emission spectra show the simultaneous presence of three bands: a short wavelength emission band (naphthalene monomer), a middle emission band (phenanthroline emission), and a long-wavelength band. All three bands were found to be dependent on the protonation state of the macrocyclic unit (including the polyaminic and phenanthroline structures). The existence of the long-wavelength emission band is discussed and is shown to im…
Micelles as containers for self-assembled nanodevices: a fluorescent sensor for lipophilicity
2008
Potentiometric titrations, fluorescence versus pH titrations, dynamic light scattering and fluorescence polarization anisotropy studies demonstrate that inside the nanodimensioned Triton X-100 micelles, 1-pyrenecarboxylic acid, PCOO-, forms an apical complex with the Zn2+ cation encircled by a lipophilic cyclen ligand and hugely increasing its fluorescence. The ability of the Zn2+-cyclen-PCOO- complex plus its micellar container to act as a fluorescent sensor to evaluate the lipophilicity of molecular species is demonstrated on the fatty acid series CH 3(CH2)xCOOH (x=0-16). At pH 7.4 a decrease in fluorescence is observed on the addition of fatty acids that is directly related to their chai…
Synthesis of new fluorescent amino acids with a triazolopyridine core: diacid sensors
2018
A new family of amino acid containing pyridine–triazolopyridine cores has been prepared by means of a copper catalysed reaction. These compounds exhibit an intense emission that has been employed to sense the distance between two carboxylic acids in a linear molecule, from oxalic to glutaric acids.
Rapid Synthesis of Unsymmetrical Sulforhodamines Through Nucleophilic Amination of a Monobrominated Sulfoxanthene Dye
2014
A transition-metal-free method for the synthesis of N-substituted unsymmetrical sulforhodamine fluorophores from an unusual monobrominated sulfoxanthene dye and primary or secondary amines by direct SNAr-type reactions is presented. The simplicity and effectiveness of this “postamination” procedure were demonstrated through the rapid preparation of a library of multifunctional red-emitting rhodamine analogues. Some of these analogues are equipped with a reactive handle and retain the two water-solubilizing sulfonic acid moieties of the starting halogenated derivative; this makes them ideal candidates for biolabeling applications. The potential utility of this expeditious strategy to finely …
Fluorescence studies of hydrophobically-modified poly(N-isopropylacrylamides) or how to play accordion on a liposome
1991
The coil/globule transition of polymers in solution is a favourite topic of discussion among polymer theoreticians. Here, this phenomenon is used to play a “molecular accordion” built with a thermosensitive polymer anchored to liposomes, a tune which mimics a natural process occuring in cell membranes.
Thioflavin T Promotes Aβ(1−40) Amyloid Fibrils Formation
2015
Fibrillogenesis of the small peptide Aβ(1-40) is considered to be the hallmark of Alzheimer's disease. Some evidence indicates small oligomers, rather than mature fibrils, as the key cytotoxic agents. The fluorescent dye Thioflavin T (ThT) is often used to detect amyloid deposits in both in vivo and in vitro experiments, and it is used to study kinetic measurements, under the fundamental hypothesis that this probe does not influence the aggregation processes. We report experimental data showing that ThT may promote the Aβ(1-40) peptide amyloid aggregation changing solvent-peptide interactions and stabilizing more ordered β-like conformation. This finding has a two-fold importance: It is a f…
The guanidinium group as a key part of water-soluble polymer carriers for siRNA complexation and protection against degradation.
2014
Here, the preparation of a novel block copolymer consisting of a statistical copolymer N-(2-hydroxypropyl) methacrylamide-s-N-(3-aminopropyl) methacrylamide and a short terminal 3-guanidinopropyl methacrylamide block is reported. This polymer structure forms neutral but water-soluble nanosized complexes with siRNA. The siRNA block copolymer complexes are first analyzed using agarose gel electrophoresis and their size is determined with fluorescence correlation spectroscopy. The protective properties of the polymer against RNA degradation are investigated by treating the siRNA block copolymer complexes with RNase V1. Heparin competition assays confirm the efficient release of the cargo in vi…