Search results for "Fluorescence"
showing 10 items of 2463 documents
Design of a generic end-to-end mission performance simulator and application to the performance analysis of the FLEX/Sentinel-3 mission
2016
La Observación de la Tierra mediante técnicas de teledetección con instrumentos ópticos en satélite tiene como objetivo monitorizar los procesos bio-geofísicos en la superficie y atmósfera terrestre, adquiriendo datos a diferentes longitudes de onda del espectro electromagnético. Con el fin de asegurar el mantenimiento de las observaciones y las capacidades para entender el sistema Tierra, nuevas misiones satelitales están siendo desarrolladas por agencias espaciales nacionales e internacionales así como organizaciones de investigación. En este contexto, los simuladores de misiones espaciales (E2ES por sus siglas en inglés, End-to-End Mission Performance Simulator) ofrecen a los científicos…
Passive direct measurement of sun-induced chlorophyll fluorescence spectrum from in vivo leaves
2022
The fluorescence of chlorophyll in vegetation is a weak signal emitted between 650 and 850 nm that is mixed with the much more intense light reflected by the leaf, which is why active methods are commonly used (through the additional contribution of controlled artificial light) or using indirect measurements instead. So, the measurement is provided just in relative units in the first case, or the accuracy of the estimate in the second case is uncertain without proper direct validation. The Thesis presents a new device, called FluoWat, for passive measurement that allows direct measurement of the fluorescence emission of leaves in vivo under natural conditions in the field with sunlight. And…
A novel water-soluble BODIPY dye as red fluorescent probe for imaging hypoxic status of human cancer cells
2020
The development of effective methods for real-time monitoring of nitroreductase (NTR) activity is of great significance for medical diagnosis and cancer research. Here, we present a novel water-soluble BODIPY-based chemodosimeter (NBB) for imaging the hypoxic status of human non-small-cell lung cancer A549 cells. We assume that ‘on–off’ response of NBB is activated by the NTRmediated reductive release of meso-phenol BODIPY dye resulting in unusual fluorescence.
The combination of PDE4 and PDE5 inhibitors reduces YAP expression in IPF
2017
Background: Pathological fibrosis is associated with repeated episodes of injury to alveolar epithelial cells of largely. Yes-associated protein (YAP) is prominently expressed in fibrotic lung. Roflumilast has demonstrated to exhibit anti-fibrosis effects, while PDE5 inhibitors (sildenafil) combinated with PDE4 inhibitors reduce fibrotic-effects secondary to TGFs1. Apparently, no studies of PDE4 and PDE5 inhibitors on YAP expression there are. Objectives: To study the effects from adding a sildenafil to Roflumilast N- oxide (RNO) on TGF-β/SMAD3/YAP pathway in IPF in vitro models. Methods: A549 cells were pre-incubated with therapeutical concentrations of RNO (2nM) and/or sildenafil (10nM) a…
Thermal induced conformational changes involved in the aggregation of beta-lactoglobulin
2005
Aggregation of proteins appears to be associated most often with conformational and structural changes that lead to exposure of some apolar residues. Depending on the native structure of the protein in exam, aggregation is a process that involves different mechanisms, whose time of occurrence and interplay can depend upon temperature. To single out information about the multistages of the aggregation pathway, here we investigate the thermally induced conformational and structural changes of the beta-lactoglobulin (BLG). The experimental approach consists in studying steady-state fluorescence spectra of intrinsic chromophores, two tryptophans, and Anylino-Naphthalene-Sulfonate dye (ANS) mole…
Cinka jonus saturoša kalcija deficīta hidroksilapatīta iegūšana un analīze
2015
Cinka jonus saturoša kalcija deficīta hidroksilapatīta iegūšana un analīze. Zepa Z., zinātniskais vadītājs Mag.chem. Andersons J., Bakalaura darbs, 40 lappuses, 26 attēli, 13 tabulas, 42 literatūras avoti, 6 pielikumi, latviešu valodā. Darbā veikta cinka jonus saturoša kalcija deficīta hidroksilapatīta (Zn-CDHAp) sintēze, kvantitatīvā un kvalitatīvā analīze. Literatūras apskatā ir apkopota informācija par kalcija fosfātiem, to veidiem, īpašībām un atbilstībai biomateriāliem. Eksperimentālajā daļā veikta Zn-CDHAp sintēze ar dažādu cinka saturu tajā. Iegūti cinku saturoši trikalcija fosfāti. Kvantitatīvo Zn-CDHAp sastāvu noteica, izmantojot rentgenfluorescences spektrometriju, bet kvalitatīvā…
Intestinal absorption pathway of gamma-aminobutyric acid in rat small intestine.
1994
Intestinal absorption of gamma-aminobutyric acid (GABA), as a model compound for gamma-aminoacids, has not been extensively studied from the kinetic viewpoint. Since data from our laboratory suggested that some competition arises between intestinal absorption of beta-alanine and GABA and since our intent was to maintain the aqueous stagnant diffusion layer in order to approach absorption tests to in vivo physiological conditions, a rat jejunum in situ study was undertaken in order to gain an insight into the mechanism of GABA absorption. In the present paper, results from assays using isotonic perfusion solutions with starting GABA concentrations ranging from 1 to 50 mM are reported. They s…
Lung on a Chip Development from Off-Stoichiometry Thiol–Ene Polymer
2021
Institute of Solid-State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2. Finally, we would like to thank Biol. Kaspars Tars from Latvian Biomedical research and study center for giving us the opportunity to participate in this consortium and contribute to Latvian scientists’ effort in response to the COVID-19 pandemic.
A Simple System Based on a Thiourea-Modified Fluorescein for ω-Amino Acid Discrimination
2015
A thiourea-modified fluorescein derivative was synthesized by reaction of fluorescein isothiocyanate with 2-(2-aminoethoxy)ethan-1-ol. UV/Vis absorption and fluorescence emission spectroscopy studies demonstrated that this heteroditopic receptor was able to discriminate among linear aliphatic ω-amino acids with different chain lengths.
Acidochromism of the luminescence of bis(4-pyridylethenyl)arenes
2004
Abstract A series of C 2 -symmetrical bis[( E )-2-(4-pyridyl)ethenyl]arenes has been synthesised via two-fold PO-activated olefinations. 1,4-Benzene, 1,4-naphthalene, 9,10-anthracene and 2,2′-diphenyl were used as central units. These fluorescent compounds were freely soluble in common solvents. The absorption and the emission were sensitive towards solvent polarity and acid, in solution as well as in the solid state. Depending on the concentration of acid, protonation of the ground state and/or the excited state caused reductions of the fluorescence efficiencies, accompanied by bathochromic shifts of the absorption and the emission spectra of some chromophores. The title compounds, except …