Search results for "Fluorescence"
showing 10 items of 2463 documents
Characterization of protofibrillar aggregates of bovine serum albumin by tryptophans fluorescence lifetime
2010
We report an experimental study on the thermally induced aggregation of Bovine Serum Albumin at basic pH. In these conditions, we observe the growth of simple protofibrillar structures via the formation of intermolecular beta-sheets promoted by the increased electrostatic repulsion. Here we present a study on the time resolved fluorescence of Tryptophans (Trp) along the aggregation kinetics in the above reported conditions. We use the lifetimes distribution approach as a useful tool for the interpretation of the fluorescence decay in terms of protein conformational substates and interconversion dynamics. Trp fluorescence lifetime depends from protein conformations, also in relation with sol…
Trennung von spaltprodukten durch Extraktionschromatographie
1970
The separation of fission products which form anionic species in mineral acids and of uranium and neptunium from samples of neutron-irradiated uranium is described. The method used is extraction chromatography with tri-n-butylphosphate (TBP) and di-(2-ethylhexyl)-orthophosphoric acid (HDEHP) as extractants and polytrifluoromonochloroethylene powder as the solid support. In the first column Zr, U and Np are extracted with TBP from 8N HNO3/NaClO3. In the second column, HDEHP is applied as extractant and 9N HCl/NaClO3 as the mobile phase for the isolation of Nb, Sb, and I, and in the third column (HDEHP), the rare earths and Mo are extracted from 0.1N HCl. Finally with the fourth column (TBP),…
Ādas fulorescences un izkliedes kinētikas mērījumi pikosekunžu lāzera ierosmē
2017
Lai gan pirmajā acu uzmetienā ādas autofluorescence un starojuma izkliedes kinētikas ir it kā vienkāršas metodes vides pētīšanai un tās parametru noteikšanai, tieši tāpēc tās ir efektīvas. Izmantojot ādas veidojumu raksturošanai metodes, kas nav nepamatoti sarežģītas, iespējams iegūt lielumus, kas raksturo dažādas ādas pataloģijas. Fotonu uzvedības ādā apraksts ir svarīga sastāvdaļa optiskās diagnostikas attīstībai. Darbā tika pētīti ādas veidojumi, izmantojot autofluroescences mērījumus un fotona lidojuma laika ādā mērījumus. Tika iegūti vairāki parametri, ar ko raksturot dažādas ādas pataloģijas, kā arī apskatīta korelācija starp autofluroescenci un fotona lidojuma laika ādā raksturlielum…
Lāzer-inducētās fluorescences pāreju no A-b kompleksa uz (1)3Sigma(+) stāvokli novērošana un analīze RbCs molekulā
2019
Šajā bakalaura darbā tika pētītas pārejas RbCs molekulā no A^1 Σ^+~b^3 Π kompleksa uz a^3 Σ^+ un X^1 Σ^+ stāvokli. Pētījuma metode bija lāzer-inducētās fluorescence kombinācijā augstas izšķiršanas spējas Furjē transformāciju spektru reģistrāciju. RbCs molekulas tika ierosinātas izmantojot titāna-safīra lāzeru. Reģistrētajos lāzer-inducētās fluorescences spektros tika novērotas intensīvas pārejas uz singleta stāvokli X^1 Σ^+ un ārkārtīgi vājas pārejas uz tripleta a^3 Σ^+ stāvokli no kopīga A-b kompleksa līmeņa. Tika noteikti relatīvie intensitāšu sadalījumi pētāmajās progresijās, kā arī novērtēta summārā intensitāšu attiecība (sazarošanās attiecība) starp pārejām uz tripleta un singleta stāv…
Advanced fluorescence microscopy for in vivo imaging of neuronal activity
2019
Brain function emerges from the coordinated activity, over time, of large neuronal populations placed in different brain regions. Understanding the relationships of these specific areas and disentangling the contributions of individual neurons to overall function remain central goals for neuroscience. In this scenario, fluorescence microscopy has been proved as the tool of choice for in vivo recording of brain activity. Optical advances combined with genetically encoded indicators allow a large flexibility in terms of spatiotemporal resolution and field of view while keeping invasiveness in living animals to a minimum. Here we describe the latest advancements in the field of linear and nonl…
Caveolin 3, flotillin 1 and influenza virus hemagglutinin reside in distinct domains on the sarcolemma of skeletal myofibers.
2011
We examined the distribution of selected raft proteins on the sarcolemma of skeletal myofibers and the role of cholesterol environment in the distribution. Immunofluorescence staining showed that flotillin-1 and influenza hemagglutinin exhibited rafts that located in the domains deficient of the dystrophin glycoprotein complex, but the distribution patterns of the two proteins were different. Cholesterol depletion from the sarcolemma by means of methyl-β-cyclodextrin resulted in distorted caveolar morphology and redistribution of the caveolin 3 protein. Concomitantly, the water permeability of the sarcolemma increased significantly. However, cholesterol depletion did not reshuffle flotillin…
Fluorimetric determination of captopril by flow injection analysis
1991
A flow injection analysis procedure is proposed for the determination of captopril. The sample solution was directly injected into the carrier-reagent stream which was prepared by a solution of ceric ions in 0.25 M sulfuric acid. The procedure is based on the fluorimetric monitoring of the formed Ce(III). Chemical, FIA, and instrumental parameters were optimized and the procedure is applied to the captopril determination in pharmaceutical formulations with competitive precision and adequate accuracy.
FIA-fluorimetric determination of adrenaline by oxidation with a solid-phase reactor of manganese dioxide incorporated in polyester resin beads
1995
Abstract The FIA-spectrofluorimetric determination of adrenaline was carried out by reaction of the drug with manganese dioxide entrapped in a polymeric material in a solid-phase reactor; the oxidized drug was monitored fluorimetrically at 540 nm (Ioxg. 330.0 nm). The calibration graph for adrenaline was linear over the range 0.5 - 20 μg ml−1 with a relative standard deviation of 2.0% (at 5 ug ml−1) and the sample throughput of 65 h−1. The influence of foreign compounds was studied and the method was applied to the determination of adrenaline content in a pharmaceutical formulation . ∗Present address: Institut of Chemistry, Warsawa University, Bialystok Branch, Bialystok, Poland.
Spectrophotometric and Fluorimetric Determination of 9-Amino Acridine by Flow Injection Analysis
1990
Abstract The spectrophotometric and fluorimetric determination of 9-amino acridine is carried out by means of the FIA procedures and on the basis of its own color or fluorescence. The methanol used as a carrier stream resulted in a significative increase in sensitivity and sample throughput. The method is applied to the drug determination in pharmaceutical formulations.
Fluorometric determination of diphenhydramine by flow-injection analysis
1992
A sensitive, rapid and simple flow injection procedure for the determination of diphenhydramine has been designed based on a fluorometric approach. An aqueous solution of diphenhydramine is injected into a carrierreagent stream containing Ce(IV) in dilute sulphuric acid and the fluorescence intensity of the Ce(III) produced is monitored. Chemical, FIA and instrumental variables were optimized. Analytical features of the method are: linear range 0.2–2 ppm, precision 0.7%, sample throughput 80/h. The influence of some foreign substances which can be found in typical pharmaceutical samples containing diphenhydramine was also investigated. The diphenhydramine content of a pharmaceutical prepara…