Národní úložiště šedé literatury Nalezeno 25 záznamů.  1 - 10dalšíkonec  přejít na záznam: Hledání trvalo 0.01 vteřin. 
Aplikační list: Aplikace pro vědy o živé přírodě. Katodoluminiscenční zobrazování
Vancová, Marie ; Krzyžánek, Vladislav ; Skoupý, Radim ; Horodyský, P.
Případové studie ukazující význam použití katodoluminiscenčního detektoru Crytur v sektoru biologických věd
Katodoluminiscenční zobrazování karotenoidů v biologických vzorcích pomocí kryo-skenovací elektronové mikroskopie s využitím funkčního vzorku katodoluminiscenčního detektoru Crytur
Vancová, Marie ; Krzyžánek, Vladislav ; Skoupý, Radim ; Horodyský, P.
Zde poprvé referujeme o katodoluminiscenčních vlastnostech karotenoidů přítomných v různých biologických vzorcích (Diplonemidae spp, kořen mrkve, embrya Arabidopsis, řasa Vischeria sp., jednobuněčná pigmentovaná kvasinka Rhodontorula, žloutek slepičího) pomocí kryo-SEM. Přítomnost karotenoidů byla prokázána Ramanovou spektroskopií.
Novel embedding resins for 3D-SEM II
Šlouf, Miroslav ; Pavlova, Ewa ; Strachota, Beata ; Strachota, Adam ; Nebesářová, Jana ; Týč, Jiří ; Krzyžánek, Vladislav ; Skoupý, Radim
Research report for Thermo Fisher Scientific s. r. o., based on common project awarded by TA CR (program: National center of competence, TN01000008).
Methodical procedures for preparation and observation of various types of biological samples using a CL detector
Vancová, Marie ; Horodyský, P. ; Kolouch, A. ; Krzyžánek, Vladislav ; Skoupý, Radim
Aplikační příklady využití funkčního vzorku katodoluminescenčního detektoru firmy Crytur pro jeho využití v biologickém výzkumu
Možnosti katodoluminiscenčního zobrazování komerčních fluoroforů a katodoluminiscenčních sond pomocí funkčního vzorku detektoru CRYTUR
Vancová, Marie ; Vaněček, Jiří ; Nebesářová, Jana ; Krzyžánek, Vladislav ; Skoupý, Radim
Možnosti katodoluminiscenčního zobrazování komerčních fluoroforů a katodoluminiscenčních sond pomocí funkčního vzorku detektoru CRYTUR
An appropriate method for assessing hydrogel pore sizes by cryo-sem
Adámková, Kateřina ; Trudicová, M. ; Hrubanová, Kamila ; Sedláček, P. ; Krzyžánek, Vladislav
The aim of our work was to examine and describe ultrastructure of the agarose hydrogel and any possible structural concentration dependencies, and to assess the distribution and size of pores of agarose hydrogel in dependence on its concentration. Four concentrations were prepared (0.5 %, 1.0 %, 2.0 % and 4.0 % of dry weight content) and cryo-SEM and turbidimetry methods were executed on wet (original) samples in order to image the ultrastructure and measure the pore sizes within. \nReasonable results were obtained for the wet samples as they were closer to their native state they are usually used for applications in. Cryo-SEM and turbidimetry provided comparable results of pore diameters and allowed to compare pore diameters dependant on the concentrations, moreover, it showed more detailed and realistic structure.
Determination of thickness refinement using STEM detector segments
Skoupý, Radim ; Krzyžánek, Vladislav
Quantitative STEM imaging together with Monte Carlo simulations of electron scattering in solids can bring interesting results about properties of many thin samples. It is possible to determine thickness of a sample, to calculate mass of particles and measure mass per length/area. Appropriate calibration is one of the crucial parts of the method. Even a small error or inaccuracy in detector response to electron beam either blanked or full brings significant error into thickness determination. This problem can be overcome by parallel STEM imaging in more segments of the detector. Comparing more segments gives a possibility to use a signal from different segments for different thicknesses of a sample. Accuracy of individual parts of the detector depends on the captured signal quantity. It is desirable to use such a STEM detector segment that provides the greatest signal change to a unit of thickness. To demonstrate the usage, we used a sample of Latex nanospheres placed on thin carbon lacey film, diameter of the nanospheres was around 600 nm in order to compare the results from different detector segments. Thanks to the known thickness of the sample (calculated from its geometrical shape), it is possible to estimate the optimal acquisition settings and post processing steps with the known and the true state of the sample.
Quantitative Imaging in Scanning Electron Microscope
Skoupý, Radim ; Buršík, Jiří (oponent) ; Shimoni, Eyal (oponent) ; Krzyžánek, Vladislav (vedoucí práce)
This thesis deals with the possibilities of quantitative imaging in scanning (transmission) electron microscope (S|T|EM) together with its correlative applications. It starts with quantitative STEM (qSTEM) method description, where estimated local sample thickness can be related to irradiated dose and create a mass-loss study, which was applied on samples of ultrathin epoxy resin sections at variate conditions (age, temperature, staining, plasma cleaning, carbon covering, probe current). The possibilities of the detector calibration process, the necessary background of the Monte Carlo simulations of electron scattering and achievable accuracy of the method are discussed and demonstrated. The method is then extrapolated for the use of back-scattered electron (BSE) detector, where new detector calibration technique, based on primary beam deflection on electron mirror, was postulated, developed and tested on various thin coating layers with thicknesses in range from 1 to 25 nm. The use of BSE detector brings the opportunity to measure the thickness of not only the electron transparent samples as in case of qSTEM, but also thin layers on substrates – qBSE. Both above-mentioned methods (qSTEM and qBSE) are intensity-based. This brings complication in the need of proper calibration, where just a slight drift of base-signal level causes a significant change of the results. This insufficiency was overcome in case of qSTEM by using the most probable scattering angle (captured by pixelated STEM detector) instead of an integral image intensity captured by an annular segment of STEM detector. The advantage of this method is its applicability post-acquisition, where no special previous actions are needed before each imaging session. The disadvantage is the limited range of detectable thicknesses given by the peak creation in signal/scattering-angle dependency. In general, low thickness region is immeasurable as well as those too thick (usable thickness range for latex is 185 - 1,000 nm; given by detection geometry and pixel size). Moreover, multiple applications of conventional and commercially available quantitative techniques of cathodoluminescence (CL) and energy-dispersive X-ray spectroscopy (EDX) are presented in correlation with high-resolution images taken in secondary and transmitted electrons.

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