Search results for "Dye"

Do fluorescence and transient absorption probe the same intramolecular charge transfer state of 4-(dimethylamino)benzonitrile?

2009

International audience; We present here the results of time-resolved absorption and emission experiments for 4-(dimethylamino)benzonitrile in solution, which suggest that the fluorescent intramolecular charge transfer (ICT) state may differ from the twisted ICT (TICT) state observed in transient absorption.

Selective labelling of melittin with a fluorescent dansylcadaverine probe using guinea-pig liver transglutaminase

1991

Abstract Melittin, a C-terminal peptide, incorporated the fluorescent probe monodansylcadaverine (DNC) when catalysed by guinea-pig liver transglutaminase and Ca2+, as determined by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). A 1:1 adduct DNC-melittin was identified in which a single glutamine residue out of two, i.e. Gln25, acts as acyl donor. Incubation of melittin with transglutaminase in the absence of DNC originated high molecular mass complexes indicative that the peptide lysine residue can act as an acyl acceptor. The DNC-melittin was about 3 times more active in the lysis of red cell membranes than native melittin. Fluorescence study of the lab…

Pyrrolo[2,3-h]quinolinones: A new ring system with potent photoantiproliferative activity

2006

A new class of compounds, the pyrrolo[2,3-h]quinolin-2-ones, nitrogen isosters of the angular furocoumarin Angelicin, was synthesized with the aim of obtaining new photochemotherapeutic agents with increased antiproliferative activity and lower undesired toxic effects than the lead compound. Two synthetic pathways were approached to allow the isolation both of the dihydroderivatives 10-17 and of the aromatic ring system 23. Compounds 10-17 showed a remarkable phototoxicity and a great UVA dose dependence reaching IC(50) values at submicromolar level. Intracellular localization of these compounds has been evaluated by means of fluorescence microscopy using tetramethylrhodamine methyl ester a…

More about the developing of invisible lipstick-contaminated lipmarks on human skin: The usefulness of fluorescent dyes

2006

At the present time fingerprints are one of the simplest, and most reliable means of identification. Increasingly, crime scene investigators look for palm, foot, ear or lip prints. With regard to lip prints, the use, very common today, of protective or permanent lipsticks allow the production an invisible lipmark (or invisible lipstick-contaminated lipmark) which is possible to develop. Some results have already been published about developers useful for different kinds of surfaces (both porous and non-porous) as well as those which are more efficient in case of old or recent prints. The latest studies are about the developing on human skin, and they prove the usefulness of lysochromes (spe…

Nerve agent simulant detection by using chromogenic triaryl methane cation probes

2012

Two triaryl methane cations have been used as probes for colorimetric detection of nerve agent simulants. Buffered mixed aqueous solutions of 1 and 2 showed bathochromic shifts in the presence of DCNP (diethylcyanophosphonate) and DCP (diethylchlorophosphate). The colour modulation can be observed to the naked eye. Appropriate mechanisms for the recognition event are proposed. © 2012 Elsevier Ltd.

Isolation and molecular characterization of brain microvascular endothelial cells from human brain tumors.

2002

Brain tumor formation and growth is accompanied by the proliferation and infiltration of blood capillaries. The phenotypes of endothelial cells that make up capillaries are known to differ not only in the tissues in which endothelial cells are located but also as a result of the microenvironment to which they are exposed. For this reason, primary cultures of brain endothelial cells were isolated from human brain tumors removed by surgery and compared with cells from normal tissue. The primary confluent monolayers that grew out of isolated capillary fragments consisted of closely associated, elongated, fusiform-shaped cells. But brain tumor-derived endothelial cells in culture exhibited sign…

An In Vitro Experiment for Postmortem Vascular Permeation. The Passage of Morphine and Morphine Glucuronides Across a Vascular Wall

1997

A venous blood sample taken at autopsy cannot be considered to represent the antemortem blood concentration of a particular substance. Autolytic processes cause disintegration and increasing permeability of the physiological and anatomical barriers such as vascular walls and lead to changes in substance concentrations. In the present study, the experimental design represents an in vitro postmortem simulation of a drug substance crossing a venous wall. The postmortem behavior of morphine, morphine-3- and morphine-6-glucuronide was investigated. A Chien-Valia-diffusion chamber with a patch of inferior vena cava as diffusion barrier was used. For optimal simulation of postmortem events, vein s…

Temporal dynamic of biofilms enhances the settlement of the central-Mediterranean reef-builder Dendropoma cristatum (Biondi, 1859).

2021

Abstract Research on marine invertebrate settlement provides baseline knowledge for restoration technique implementation, especially for biogenic engineers with limited dispersion ability. Previously, we determined that the maturity of a biofilm strongly enhances the settlement of the vermetid reef-builder Dendropoma cristatum. To elucidate settlement-related biofilm features, here we analyse the structure and composition of marine biofilms over time, through microscopic observations, eukaryotic and prokaryotic fingerprinting analyses and 16S rDNA Illumina sequencing. The vermetid settlement temporal increase matched with the higher biofilm coverage on the substratum and the reduction of th…

Picosecond absorption spectroscopy: Methods and applications in photophysical and photochemical systems

1985

Warm white LEDs based on Lumogen® Red and Yellow

2013

One of the most widespread solutions for the production of white LEDs is the frequency downconversion of a part of the light, coming from a blue source, by exciting one or more materials (typically Ce:YAG) that emit at longer wavelength [1]. In this work we report ona simple and less expensive method to fabricate warmwhite-light LEDsusingthe photoluminescence of Lumogen®, a perylene-based polymer dyecommercialized by BASF,that has already beenprovedto be a good substitute for conventi onal inorganic colour conversion [2],[3]. Standard InGaN-based blue LEDs (~ 450 nm) were fabricated on a sapphire substrate by metal organic chemical vapour deposition. Both Lumogen® Yellow, and Red dyes wered…