Wyniki wyszukiwania - BazTech

1

Towards in-vivo assessment of fluorescence lifetime: imaging using time-gated intensified CCD camera

Sawosz P., Wojtkiewicz S., Kacprzak M., Zieminska E., Morawiec M., Maniewski R., Liebert A.

Biocybernetics and Biomedical Engineering

|

2018

|

Vol. 38, no. 4

966--974

EN

A novel technique for imaging of a small animal with application of time-gated intensified CCD camera was proposed. The time-resolved method based on emission of picosecond light pulses and detection of the light penetrating in tissues was applied. In this technique, the fluorescence photons, excited in the dye circulating in the tissue, that diffusely penetrate in the optically turbid medium are detected. The data acquired during measurements carried out on a rat was analyzed in order to estimate fluorescence life time which depends strongly on the environment in which the dye is distributed. In the life time estimation a special emphasis was put on compensation of influence of the instrumental response function of the setup on the measured quantity. The proposed optical system was validated in series of phantom experiments, in which estimates of fluorescence lifetime of inclusions containing indocyanine green (ICG) were obtained. ICG is a dye revealing florescence properties in near-infrared wavelength region. Images of the estimate of fluorescence lifetime of the ICG accumulated in tissues of a rat were successfully acquired around six circular spots of illumination of the diameter of 6mm. Larger lifetime values were observed in lung/heart region of the animal. Aspect of sampling rate of the fluorescence lifetime images optimization was finally discussed.

2

Wzrost i właściwości optyczne kryształu BaGd2 (MoO4)4 domieszkowanego Er3+

Han S., Wang J., Zhang H., Pan S., Xv H., Wang Y., Shen C.

Chemik

|

2013

|

Vol. 67, nr 9

763--770

PL

Pojedynczy kryształ BaGd2(MoO4)4 domieszkowany 1% at. Er3+ wyhodowano metodą Czochralskiego. Omówiono szczegóły procedury otrzymywania i wzrostu kryształu. Kryształ ma doskonałą płaszczyznę poślizgu (010), a jego łupliwość czyni go przydatnym jako ośrodek czynny w mikrolaserach. Zmierzono widmo absorpcyjne w zakresie światła widzialnego i bliskiej podczerwieni (NIR) w temperaturze pokojowej. W zakresie od 380 do 1600 nm występuje kilka intensywnych pików absorpcyjnych. Zmierzono również widmo fluorescencyjne wzbudzane za pomocą lampy ksenonowej. Zaobserwowano intensywny pik emisyjny NIR 1536 nm. Czasy trwania fluorescencji 4I13/2 oraz 4I11/2 wyznaczone za pomocą dopasowania krzywej wykładniczej wyniosły odpowiednio 5,85 ms i 112,62 μs. Ciepło właściw Er3+ BaGd2(MoO4)4 w 25°C wynosi 0,471 J g-1 K-1. Na podstawie zmierzonych widm obliczono parametry optyczne na podstawie teorii Judda-Ofelta (J–O).

EN

A 1 at % Er3+ doped BaGd2(MoO4)4 single crystal was grown by the Czochralski method. Details on the preparation and growth procedures were discussed. The crystal has a perfect (010) cleavage plane, and the cleavage character makes the crystal suitable as a gain medium for microchip lasers. The absorption spectrum in the visible and near-infrared (NIR) regions was measured at room temperature. There are several strong absorption peaks in the range from 380 to 1600 nm. The fluorescence spectrum excited by a Xenon lamp was also measured. A strong NIR emission peak located at 1536 nm was observed. The fluorescence lifetimes of 4I13/2 and 4I11/23+:BaGd2(MoO4)4 at 25°C is 0.471 J g-1 K-1. Using the measured spectra, the optical parameters were calculated using the J–O theory.

3

The effect of immobilization in the PVA films on the fluorescence and phosphorescence lifetime of indole and its derivatives

Kowalska-Baron A., Choudhary P., Montes D.

Biotechnology and Food Science

|

2011

|

Vol. 75, nr 2

3-14

EN

This work is devoted to study how immobilization in the PVA films affects the fluorescence and phosphorescence lifetime of indole and its derivatives. The obtained results indicated that immobilization of the studied indoles in the PVA matrix, which leads to the increased microrigidity of the environment around the indole moiety, results in the increase of singlet and triplet excited state lifetime of the studied compounds. Most probably, the enhancement of the rigidity of the environment near the chromophore reduces the rates of the non-radiative deactivation pathways, which leads to the increase of excited state lifetimes of the studied compounds.

4

Szkło dla fotoniki. Cz. 9, Rodzaje szkieł laserowych

Romaniuk R.

Elektronika : konstrukcje, technologie, zastosowania

|

2009

|

Vol. 50, nr 6

69-74

PL

W artykule, który jest dziewiątą częścią cyklu prac o szkłach dla fotoniki, dokonano przeglądu najczęściej stosowanych rodzajów aktywnych szkieł laserowych domieszkowanych jonami ziem rzadkich. Przedstawiono rodzaje jonów domieszki aktywnej wraz z ich charakterystykami oraz właściwościami szkieł nimi domieszkowanych. Porównano układy domieszkowanych szkieł laserowych bazujących na różnych tlenkach, fluorkach oraz siarczkach (i rodziny takich szkieł). Podkreślono optymalne cechy jakimi powinny charakteryzować się idealne szkła laserowe dla konkretnych zastosowań.

EN

The paper, which is the ninth part of a cycle on glasses for photonics, is a concise review of the most frequently used kinds of active laser glasses doped with rare earth ions. There are presented kinds of used rare earth ions together with their characteristics and properties of glasses doped with these ions. There are compared glass systems with rare earths based on oxides, fluorides and sulfides (and related systems). The emphasis is on optimal features of idea I laser glasses required for various applications.

5

Zastosowanie techniki stroboskopowej do pomiarów czasów życia fluorescencji materiałów biologicznych. Cz. 1, Podstawy metody, aparatura i metodyka pomiarów

Włodarski M., Kwaśny M., Kaliszewski M., Rutecka B.

Biuletyn Wojskowej Akademii Technicznej

|

2009

|

Vol. 58, nr 4

165-176

PL

W pracy przedstawiono podstawy stroboskopowej metody pomiarów czasów życia fluorescencji, aparaturę, opracowaną metodykę pomiarów i analizę procesu dekonwolucji sygnałów. Pokazano, że krzywe zaniku fluorescencji z wykorzystaniem źródeł światła typu LED UV, (280 i 340 nm) mogą znaleźć zastosowanie do charakterystyki aminokwasów, białek, bakterii - w tym symulantów i interferentów bojowych środków biologicznych. Podstawowymi zaletami metody są: jej szybkość, możliwość wykorzystania tanich źródeł wzbudzenia, wysoka czułość, prostota obsługi, modułowa budowa umożliwiająca szybką wymianę źródeł wzbudzenia. Badania przeprowadzone na standardowych wzorcach - NATA, NADH wykazały zgodność czasów życia fluorescencji z danymi literaturowymi.

EN

Stroboscopic method for determination of fluorescence lifetimes, using 280 nm and 340 nm UV LED sources, may be used for characterization of biological substances - including simulants and interferents of Biological Warfare Agents (BWA). Main advantages of this method are: quickness of measurement, cheap UV sources, high sensitivity, simplicity of operation, modular construction allowing quick changing of sources. Principle of stroboscopic method, developed method of measurements and analysis of deconvolution process are presented in this work. Results of measurement of NATA and NADH standards correspond to data published by other authors.

6

Fluorescence detection of biological objects with ultraviolet and visible light-emitting diodes

Kurilcik N., Vitta P., Zukauskas A., Gaska R., Ramanavicius A., Kausaite A., Jursenas S.

Optica Applicata

|

2006

|

Vol. 36, nr 2-3

193-198

EN

Recent progress in fabrication of semiconductor light emitting diodes (LEDs) allows these devices to be used for excitation of fluorescence of aromatic amino acids and other biofluorophores. In our work, a deep-UV UVTOPTM LED (280 nm) developed by Sensor Electronic Technology, Inc., was used for fluorescence characterisation of natural protein fluorophores in enzyme glucose oxidase (GOx) and in Bacillus subtilus dry spores (B. subtilus). A longer-wavelength Nichia LED (375 nm) and high-power LuxeonTM LED (450 nm) were used for fluorescence detection of enzyme cofactors. Combined spectral and fluorescence lifetime measurements using selective LED excitation enabled us to recognise the impact of specific autofluorophores in complex biological systems. Inexpensive LED-based fluorescence detectors can be used in designing biosensors and detect-to-warn systems.

7

Photophysics of Lumichrome and Its Analogs

Sikorska E., Worrall D., Bourdelande J., Sikorski M.

Polish Journal of Chemistry

|

2003

|

Vol. 77 / nr 1

65-73

EN

The spectroscopic and photophysical properties of lumichrome and its 1- and 3-methyl and 1,3-dimethyl derivatives in acetonitrile and in methanol are presented. In common with the parent molecule, the photophysics of the lumichrome methyl derivatives are dominated by non-radiative transitions in both methanol and acetonitrile. However, fluorescence yields in methanol are higher than in acetonitrile as a result of a reduction in the efficiency of non-radiative deactivation channels. These observations are discussed in terms of the available solvent-solute interactions.