Search results for " Oxazines"
showing 6 items of 6 documents
Differential reactivity of fluorinated homopropargylic amino esters vs gold(I) salts. The role of the nitrogen protecting group
2015
The reaction of several homopropargyl amino esters 4, bearing aromatic substituents and a benzyl group as nitrogen substituents, with gold(I) salts gave rise to fluorinated quinolines 6 in a tandem hydroarylation-isomerization process. On the other hand, homopropargyl amino esters 7 containing a carbamate group underwent the carbonyl addition over the triple bond in the presence of gold(I) salts, rendering fluorinated oxazines 8. The use of chiral sulfoxides allowed us to develop the asymmetric version of this protocol. This two processes complete the differential reactivity showed by these types of susbtrates, depending on the nature of the nitrogen protecting group. (C) 2014 Elsevier B.V.…
A new multi analytical approach for the identification of synthetic and natural dyes mixtures. The case of orcein-mauveine mixture in a historical dr…
2017
In this paper, the application of a multi-analytical approach for the characterisation of synthetic and natural dyes in a historical textile is presented. The work is focused on a historical dress of a Sicilian noblewoman, dating from about 1865–1870. Firstly, SERS on fibre was performed, in order to individuate the classes of dyes employed. The SERS spectra suggested the presence of two main dyes: mauveine and orcein. In order to confirm these preliminary results, two different extraction protocols were applied. The extracts obtained were analysed by ESI-MS, MALDI-ToF and UHPCL-MS analyses, confirming the SERS results. In particular, the application of the ammonia mild extraction technique…
Nile Red lifetime reveals microplastic identity
2020
Microplastic pollution is recognized as a worldwide environmental problem. The increasing daily use and release of plastics into the environment have led to the accumulation of fragmented microplastics, with potentially awful consequences for the environment, and animal and human health. The detection and identification of microplastics are of utmost importance, but available methods are still limited. In this work, a new approach is presented for the analysis of microplastics based on hydrophobic fluorescence staining with Nile Red, using spectrally resolved confocal fluorescence microscopy and fluorescence lifetime imaging microscopy (FLIM). Significant differences were observed in the em…
FRET multiphoton spectral imaging microscopy of 7-ketocholesterol and Nile Red in U937 monocytic cells loaded with 7-ketocholesterol.
2004
To show the effect of 7-ketocholesterol (7KC) on cellular lipid content by means of flow cytometry and the interaction of 7KC with Nile Red (NR) via ultraviolet fluorescence resonance energy transfer (FRET) excitation of NR on U937 monocytic cells by means of 2-photon excitation confocal laser scanning microscopy (CLSM).Untreated and 7KC-treated U937 cells were stained with NR and analyzed by flow cytometry and CLSM. 3D sequences of images were obtained by spectral analysis in a 2-photon excitation CLSM and analyzed by the factor analysis of medical image sequences (FAMIS) algorithm, which provides factor curves and images. Factor images are the result of the FAMIS image processing method, …
Deconvolution procedure of the UV-vis spectra. A powerful tool for the estimation of the binding of a model drug to specific solubilisation loci of b…
2015
UV-vis-spectra evolution of Nile Red loaded into Tween 20 micelles with pH and [Tween 20] have been analysed in a non-conventional manner by exploiting the deconvolution method. The number of buried sub-bands has been found to depend on both pH and bio-surfactant concentration, whose positions have been associated to Nile Red confined in aqueous solution and in the three micellar solubilisation sites. For the first time, by using an extended classical two-pseudo-phases-model, the robust treatment of the spectrophotometric data allows the estimation of Nile Red binding constant to the available loci. Hosting capability towards Nile Red is exalted by the pH enhancement. Comparison between bin…
Durability of Dolutegravir-Based Regimens: A 5-Year Prospective Observational Study
2021
This study evaluates the frequency and causes of dolutegravir (DTG) discontinuation along 5 years of follow-up, in both antiretroviral treatment (ART)-naive and experienced people living with HIV (PLWH). This is a prospective multi-center cohort study enrolling PLWH on DTG from July 2014 until November 2020. DTG-durability was investigated using the Kaplan-Meier survival curve. The Cox proportional-hazards model was used for estimating the hazard ratio (HR) of DTG discontinuation for any cause, and for adverse events (AEs). Nine hundred sixty-three PLWH were included, 25.3% were women and 28.0% were ART-naive. Discontinuations for any causes were 10.1 [95% confidence interval (95% CI) 8.9-1…