Search results for "Fluorescence"
showing 10 items of 2463 documents
Quantum jump statistics with a shifted jump operator in a chiral waveguide
2019
Resonance fluorescence, consisting of light emission from an atom driven by a classical oscillating field, is well-known to yield a sub-Poissonian photon counting statistics. This occurs when only emitted light is detected, which corresponds to a master equation (ME) unraveling in terms of the canonical jump operator describing spontaneous decay. Formally, an alternative ME unraveling is possible in terms of a shifted jump operator. We show that this shift can result in sub-Poissonian, Poissonian or super-Poissonian quantum jump statistics. This is shown in terms of the Mandel Q parameter in the limit of long counting times, which is computed through large deviation theory. We present a wav…
Fluorescence quenching by trapped charge carriers in N,N-dimethylaminobenzylidene 1,3-indandione films
2010
Effects caused by the applied voltage on the steady state and time-resolved fluorescence of vacuum evaporated N,N-dimethylaminobenzylidene 1,3-indandione films sandwiched between gold and aluminium electrodes were investigated and discussed. Fluorescence enhancement and quenching as well as the fluorescence band narrowing depending on the applied voltage have been observed. Fluorescence decay and recovery take place on a time scale of tens of seconds after voltage is switched on and off. Similar fluorescence decay also takes place after switching on the excitation light. These fluorescence changes are attributed to the exciton quenching by trapped charge carriers.
Synthesis and Characterization of Adducts Derived from the syn-Diastereomer of Benzo[a]pyrene 7,8-Dihydrodiol 9,10-Epoxide and the 5‘-d(CCTATAGATATCC…
1996
5'-d(CCTATAGATATCC) was reacted with each syn-enantiomer of trans-7,8-dihydroxy 9,10-epoxy 7,8,9,10-tetrahydrobenzo[a]pyrene (syn-BPDE). The (-)-enantiomer yielded one dominating adduct, whereas the (+)-enantiomer resulted in two major adducts. As indicated by optical spectroscopic methods, the major adduct derived from both (-)- and (+)-syn-BPDE involves cis addition of the C-10 position of the diol epoxide to the exocyclic amino group of deoxyguanosine [(-)-syn-BPDEc-N2-dG and (+)-syn-BPDEc-N2-dG, respectively], whereas the minor (+)-syn-BPDE adduct is identical to a trans adduct [(+)-syn-BPDEt-N2-dG]. The cis adducts as well as the (+)-syn-BPDEt-N2-dG adduct are chemically stable for sev…
Ex Vivo Tracking of Endogenous CO with a Ruthenium(II) Complex.
2017
[EN] A two-photon fluorescent probe based on a ruthenium(II) vinyl complex is capable of selectively detecting carbon monoxide in cells and ex vivo using mice with a subcutaneous air pouch as a model for inflammation. This probe combines highly selective and sensitive ex vivo detection of endogenous CO in a realistic model with facile, inexpensive synthesis, and displays many advantages over the widely used palladium-based systems.
Triazolopyridines. Part 25: Synthesis of new chiral ligands from [1,2,3]triazolo[1,5-a]pyridines
2007
The synthesis of new chiral triazolopyridine ligands possessing fluorescent properties is described. The triazolo ring opening was studied in order to obtain new chiral 2,6-disubstituted pyridines. A preliminary coordination assay with Zn(II) is also presented.
Molecular topology applied to the discovery of 1-benzyl-2-(3-fluorophenyl)-4-hydroxy-3-(3-phenylpropanoyl)-2H-pyrrole-5-one as a non-ligand-binding-p…
2014
We report the discovery of 1-benzyl-2-(3- fluorophenyl)-4-hydroxy-3-(3-phenylpropanoyl)-2H-pyrrole- 5-one as a novel non-ligand binding pocket (non-LBP) antagonist of the androgen receptor (AR) through the application of molecular topology techniques. This compound, validated through time-resolved fluorescence resonance energy transfer and fluorescence polarization biological assays, provides the basis for lead optimization and structure−activity relationship analysis of a new series of non-LBP AR antagonists. Induced-fit docking and molecular dynamics studies have been performed to establish a consistent hypothesis for the interaction of the new active molecule on the AR surface. Refereed/…
Binding Mode and Selectivity of a Scorpiand-Like Polyamine Ligand to Single- and Double-Stranded DNA and RNA: Metal- and pH-Driven Modulation
2017
The interaction of a polyazacyclophane ligand having an ethylamine pendant arm functionalized with an anthryl group (L), with the single-stranded polynucleotides polyA, polyG, polyU, and polyC as well as with the double-stranded polynucleotides polyA-polyU, poly(dAT)(2), and poly(dGC)(2) has been followed by UV/Vis titration, steady state fluorescence spectroscopy, and thermal denaturation measurements. In the case of the single-stranded polynucleotides, the UV/Vis and fluorescence titrations permit to distinguish between sequences containing purine and pyrimidine bases. For the double-stranded polynucleotides the UV/Vis measurements show for all of them hypochromicity and bathochromic shif…
Polyamines containing naphthyl groups as pH-regulated molecular machines driven by light
2001
A series of compounds made up by linking methylnaphthalene fragments at both ends of different polyamine chains have shown to behave as pH-regulated molecular machines driven by light and fluorescence emission studies have proved the formation of an excimer between the two naphthalene units whose appearance, fluorescence intensity and decay times depend on the pH value of the media. Albelda Gimeno, Maria Teresa, Teresa.Albelda@uv.es ; Garcia-España Monsonis, Enrique, Enrique.Garcia-Es@uv.es ; Soriano Soto, Concepción, Concepcion.Soriano@uv.es
Detection of Single Oxygen Molecules with Fluorescence-Labeled Hemocyanins
2005
This study introduces a method to detect individual oxygen molecules by fluorescence microscopy of single hemocyanins. These respiratory proteins from a tarantula bind oxygen with high affinity. A spectrometric signature of the oxygenated protein is transferred to an attached fluorescence label, which can be detected at the single-molecule level. This technique opens new perspectives for the development of small and sensitive oxygen sensors as well as for the investigation of cooperative oxygen binding in respiratory proteins.
Concave macrobicycles: Absorption spectra, luminescence properties, and endocavital complexation of neutral organic guests
1996
By a mild modified Eglinton coupling a series of diynebridged macrobicyclic hosts capable of endocavital complexation were synthesized and their structures and complexation properties investigated by X-ray analysis. The inclusion of DMSO in 7 suggests a direct correlation between steric fit and orientation of the guest. On the basis of this hypothesis, the orientation of acetone in an endocavital inclusion of 2 was predicted and verified by X-ray analysis. Comparison of the single-crystal X-ray structures of the vacant macrobicycle 3 and of a family of macrobicycles showing endocavital or “pocket” complexation of neutral organic guests suggests that torsion of the cavities upon complexation…