Search results for "Chromophore"
showing 9 items of 309 documents
Design, Synthesis and Characterization of a Visible-Light-Sensitive Molecular Switch and Its PEGylation Towards a Self-Assembling Molecule.
2022
HBDI-like chromophores represent a novel set of biomimetic switches mimicking the fluorophore of the green fluorescent protein that are currently studied with the hope to expand the molecular switch/motor toolbox. However, until now members capable of absorbing visible light in their neutral (i. e. non-anionic) form have not been reported. In this contribution we report the preparation of an HBDI-like chromophore based on a 3-phenylbenzofulvene scaffold capable of absorbing blue light and photoisomerizing on the picosecond timescale. More specifically, we show that double-bond photoisomerization occurs in both the E-to-Z and Z-to-E directions and that these can be controlled by irradiating …
Semi-automatic detection of skin malformations by analysis of spectral images
2013
The multi-spectral imaging technique to reveal skin malformations has been described in this work. Four spectral images taken at polarized monochromatic LED illumination (450nm, 545nm, 660nm and 940 nm) and polarized white LED light imaged by CMOS sensor via cross-oriented polarizing filter were analyzed to calculate chromophore maps. The algorithm based on skin color analysis and user-defined threshold selection allows highlighting of skin areas with predefined chromophore concentration semi-automatically. Preliminary results of clinical tests are presented.
Determination of chromophore distribution in skin by spectral imaging
2012
Possibilities to determine chromophore distribution in skin by spectral imaging were explored. Simple RGB sensor devices were used for image acquisition. Totally 200 images of 40 different bruises of 20 people were obtained in order to map chromophores bilirubin and haemoglobin. Possibilities to detect water in vitro and in vivo were estimated by using silicon photodetectors and narrow band LEDs. The results show that it is possible to obtain bilirubin and haemoglobin distribution maps and observe changes of chromophore parameter values over time by using a simple RGB imaging device. Water in vitro was detected by using differences in absorption at 450 nm and 950 nm, and 650 nm and 950 nm.
3×3 Technique for RGB Snapshot Mapping of Skin Chromophores
2015
Three monochromatic spectral images have been extracted from a single RGB image data set at simultaneous illumination of skin by 473nm, 532nm and 609nm spectral lines. They were further transformed into distribution maps of three skin chromophores - melanin, oxy-hemoglobin and deoxy-hemoglobin, related to pigmented and vascular skin malformations. Performance and clinical potential of the proposed 3×3 technique is discussed.
Skin chromphore mapping by means of a modified video-microscope for skin malformation diagnosis
2013
Many spectral imaging devices are commercially available and used to detect certain skin pathology; however an alternative cost-efficient device can provide an advanced spectral analisys of skin. Multispectral device for diagnosis of pigmented skin lesions was developed and tested. Possibilities to map skin chromophores using a modified low-cost digital video-microscope is discussed. It was adapted for an advanced skin microscopy and used for detailed spectral analysis of skin. The device comprises CMOS digital imaging sensor, four-colour LED illumination system and image acquisition optics. The main goal is to obtain a set of spectral images of the skin area of interest for further convers…
Properties of EO Active Molecular Glasses Based on Indandione and Azobenzene Chromophores
2012
Continuing previous research of EO active materials we have focused our attention on compounds employing two types of core nonlinear optical (NLO) chromophores – indandione and azobenzene . Coupling of them with bulky triphenyl, pentafluorophenylmethoxy ester, benzyloxy ester molecular fragments, as anti-crystallization agents allows us to obtain amorphous materials for potential NLO applications.
Effect of Gold(I) on the Room-Temperature Phosphorescence of Ethynylphenanthrene.
2020
The synthesis of two series of gold(I) complexes containing the general formulae PR 3 ‐Au‐C≡C‐phenanthrene (PR 3 = PPh 3 ( 1a / 2a ), PMe 3 ( 1b / 2b ), PNaph 3 ( 1c / 2c )) or (diphos)(Au‐C≡C‐phenanthrene) 2 (diphos = 1,1‐ bis (diphenylphosphino)methane, dppm ( 1d / 2d ); 1,4‐ bis (diphenylphosphino)butane, dppb ( 1e / 2e )) have been synthesized. The two series differ on the position of the alkynyl substituent on the phenanthrene chromophore, being at the 9‐position (9‐ethynylphenanthrene) for the L1 ‐series and at the 2‐position (2‐ethynylphenanthrene) for the L2 ‐series. The compounds have been fully characterized by 1 H and 31 P NMR and IR spectroscopy, mass spectrometry and single cry…
Synthesis, Electrochemistry, and Photophysics of Aza-BODIPY Porphyrin Dyes
2016
International audience; The synthesis of dyad and triad aza-BODIPY-porphyrin systems in two steps starting from an aryl-substituted aza-BODIPY chromophore is described. The properties of the resulting aza-BODIPY-porphyrin conjugates have been extensively investigated by means of electrochemistry, spectroelectrochemistry, and absorption/emission spectroscopy. Fluorescence measurements have revealed a dramatic loss of luminescence intensity, mainly due to competitive energy transfer and photoinduced electron transfer involving charge separation followed by recombination.
Tadpole Responses to Environments With Limited Visibility: What We (Don’t) Know and Perspectives for a Sharper Future
2022
Amphibian larvae typically inhabit relatively shallow freshwater environments, and within these boundaries there is considerable diversity in the structure of the habitats exploited by different species. This diversity in habitat structure is usually taken into account in relation to aspects such as locomotion and feeding, and plays a fundamental role in the classification of tadpoles into ecomorphological guilds. However, its impact in shaping the sensory worlds of different species is rarely addressed, including the optical qualities of each of these types of water bodies and the challenges and limitations that they impose on the repertoire of visual abilities available for a typical vert…