Search results for "Fluorescence"
showing 10 items of 2463 documents
Interaction Between drug loaded Polyaspartamide-polylactide-polisorbate based micelles and cell membrane models: a calorimetric study
2011
Amphiphilic biodegradable copolymers, for their ability to self-assemble into micelle-like aggregates, with a suitable loading capacity, are of emerging interest for the delivery of water-insoluble drugs. α,β-Poly[(N-hydroxyethyl)-dl-aspartamide] (PHEA) is suitable to obtain amphiphilic graft copolymers. These copolymers can be obtained starting from PHEA-ethylenediamine (PHEA-EDA) which is functionalized with polysorbate 80 (PS₈₀, like targeting residues to the brain) and polylactide (PLA, like hydrophobic chains) in order to obtain polymeric micelles of PHEA-EDA-PS₈₀-PLA potentially useful to release drugs to the central nervous system. In this paper, the interaction and absorption of PHE…
Unusual triskelion patterns and dye-labelled GUVs: consequences of the interaction of cholesterol-containing linear-hyperbranched block copolymers wi…
2015
Cholesterol (Ch) linked to a linear-hyperbranched block copolymer composed of poly(ethylene glycol) (PEG) and poly(glycerol) (hbPG) was investigated for its membrane anchoring properties. Two polyether-based linear-hyperbranched block copolymers with and without a covalently attached rhodamine fluorescence label (Rho) were employed (Ch-PEG30-b-hbPG23 and Ch-PEG30-b-hbPG17-Rho). Compression isotherms of co-spread 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) with the respective polymers were measured on the Langmuir trough and the morphology development of the liquid-condensed (LC) domains was studied by epi-fluorescence microsc…
Diversity of freshwater Epsilonproteobacteria and dark inorganic carbon fixation in the sulphidic redoxcline of a meromictic karstic lake.
2015
Sulfidic redoxclines are a suitable niche for the growth and activity of different chemo- and photolithotrophic sulphide-oxidizing microbial groups such as the Epsilonproteobacteria and the green sulfur bacteria (GSB). We have investigated the diversity, abundance and contribution to inorganic carbon uptake of Epsilonproteobacteria in a meromictic basin of Lake Banyoles. CARD-FISH counts revealed that Epsilonproteobacteria were prevalent at the redoxcline in winter (maximum abundance of 2 × 10(6) cells mL(-1), ≈60% of total cells) but they were nearly absent in summer, when GSB bloomed. This seasonal trend was supported by 16S rRNA gene pyrotag datasets, which revealed that the epsilonprote…
Functional size of complement and perforin pores compared by confocal laser scanning microscopy and fluorescence microphotolysis
1991
Abstract Confocal laser scanning microscopy and fluorescence microphotolysis (also referred to as fluorescence photobleaching recovery) were employed to study the transport of hydrophilic fluorescent tracers through complement and perforin pores. By optimizing the confocal effect it was possible to determine the exclusion limit of the pores in situ, i.e. without separation of cells and tracer solution. Single-cell flux measurements by fluorescence microphotolysis yielded information on the sample population distribution of flux rates. By these means a direct comparison of complement and perforin pores was made in sheep erythrocyte membranes. In accordance with previous studies employing a v…
Acceleration of the through space S1 energy transfer rates in cofacial bisporphyrin bio-inspired models by virtue of substituents effect on the Först…
2011
The singlet k(ET) for cofacial β-octaalkylporphyrin/bis(meso-aryl)porphyrin dyads increases linearly with the gap between the donor-acceptor 0-0 fluorescence peaks at 77 K.
Autofluorescence imaging of basal cell carcinoma by smartphone RGB camera
2015
The feasibility of smartphones for in vivo skin autofluorescence imaging has been investigated. Filtered autofluorescence images from the same tissue area were periodically captured by a smartphone RGB camera with subsequent detection of fluorescence intensity decreasing at each image pixel for further imaging the planar distribution of those values. The proposed methodology was tested clinically with 13 basal cell carcinoma and 1 atypical nevus. Several clinical cases and potential future applications of the smartphone-based technique are discussed.
Synthèse in situ de fluorophores organiques : formation de liaisons covalentes par déclenchement enzymatique et applications en biodétection
2017
Fluorescence imaging is a growing field of biology over the past decades. Intensive works mainly focused on instrumental developments and chemistry of contrast agents (probes), were already done to improve such bioanalytical technique. The main goal of this Ph. D. thesis was to explore various fluorogenic molecular platforms responsive to various (bio)chemical stimuli and capable of releasing organic fluorophores in the biological medium to analyze. This approach named "in-situsynthesis" is based on domino reactions belonging to the repertoire of "covalent chemistry", triggered by the target (bio)analyte. This kind of process should provide advanced fluorogenic probes with high signal-to-no…
THE LIGHT-HARVESTING SYSTEM OF THE UNICELLULAR ALGA Mantoniella squamata (PRASINOPHYCEAE): EVIDENCE FOR THE LACK OF A PHOTOSYSTEM I-SPECIFIC ANTENNA …
1993
The light-harvesting complexes (LHC) were isolated from the unicellular alga Mantoniella squamata (Prasinophyceae) by sucrose-density centrifugation. Beside the major LHC (II), a photosystem I complex was obtained that could be dissociated into a photosystem I core complex and an associated LHC I. In contrast to other chlorophyll b-containing antennae, both LHC II as well as LHC I were observed to be identical with respect to the following features: the molecular weights, the isoelectric points and the retention behavior on anion-exchange chromatography of the apoproteins, the pigment content and the absorption and fluorescence spectra
Analysis of toxic elements in plastic components for toys. Multi-elemental determination by x-ray fluorescence
1993
Abstract An x-ray fluorescence method is proposed for the multi-elemental determination of toxic elements in plastic articles for children, viz., Sb(III), Ba, Cd, Cr(III), Hg, Pb and As(III). Mineralization is achieved by using molten sodium hydroxide to decompose the organic matrix, with sodium nitrate as auxiliary oxidant. Stable solutions containing the chemical species for analysis are obtained. The species are separated from the solution by (co)precipitation, in a medium of NH+4-NH3 buffer (pH 8.5) with sodium diethyldithiocarbamate, sodium rhodizonate and Fe3+, which acts as a carrier. The precipitates deposited on filter-paper are placed in the x-ray spectrometer in fine layer morpho…
Multi-sensor spectral synergies for crop stress detection and monitoring in the optical domain: A review
2022
Remote detection and monitoring of the vegetation responses to stress became relevant for sustainable agriculture. Ongoing developments in optical remote sensing technologies have provided tools to increase our understanding of stress-related physiological processes. Therefore, this study aimed to provide an overview of the main spectral technologies and retrieval approaches for detecting crop stress in agriculture. Firstly, we present integrated views on: i) biotic and abiotic stress factors, the phases of stress, and respective plant responses, and ii) the affected traits, appropriate spectral domains and corresponding methods for measuring traits remotely. Secondly, representative result…