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Tuned semiconductor laser for the diagnostic of the channel waveguides
Ondráček, František ; Skalský, Miroslav ; Čtyroký, Jiří
In contribution is described new measuring set up with tuned semiconductor laser and there are given first results of spectral losses and group refractive index in various channel waveguides by using a resonator method. The waveguides were prepared in special glasses by ion exchanges method and in LiNbO.sub.3./sub. crystal by proton exchange and also by titan difusion. Experimental results have demonstrated accuracy and rate of this arangement. In conclusion we have shown the possibility of the next research.
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Transcriptional analysis of genes coding for ion pumps during cold acclimation in drosophilid flies
ŠIMŮNKOVÁ, Petra
The relative abundance of mRNA transcripts of genes coding for {$\alpha$} subunit of Na+K+-ATPase and Vha55 (B) subunit of H+-ATPase were examined (using the qRT-PCR method) in third instar larvae of two fly species, Drosophila melanogaster and Chymomyza costata, that were reared at various acclimation conditions. No differences in mRNA levels were observed in D. melanogaster Malpighian tubules and central nervous system (CNS), when the flies were reared at 25°C or 15°C. C. costata revealed the up-regulation of both ion pump genes in the CNS at 15°C (in comparison to 25°C), and also after the transfer from 25°C to 15°C. This result indicates that compensation of ion pumps function took place at moderately low temperature (still permissive for continuation of activity, growth and development). In contrast, down-regulation of both ion pump genes was seen in the CNS of C. costata larvae at temperature of 5°C. It indicates that channel arrest strategy was adopted at very low temperatures (inducing dormancy).
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Prospects of the scanning low energy electron microscopy in materials science
Mikmeková, Šárka ; Hovorka, Miloš ; Konvalina, Ivo ; Müllerová, Ilona ; Frank, Luděk
The use of the scanning low energy electron microscopy (SLEEM) has been slowly making its way into the field of materials science, hampered not by limitations in the technique but rather by the relative scarcity of these instruments in research institutes and laboratories. Various techniques exist which are capable of studying the material microstructure, with the scanning electron microscopy (SEM), (scanning) transmission microscopy ((S)TEM) and focused ion beam (FIB) microscopy being perhaps the most known. A specific way to visualizing the microstructure of materials at high spatial resolution, to achieve a high contrast between grains in polycrystals and very fast data acquisition is to use the cathode lens (CL) mode in SEM. The CL mode in the SEM enables us to detect slow but not only slow, high angle scattered electrons that carry mainly crystallographic contrast based on the electron channeling, mostly in the Mott scattering angular range.
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Studium transportu iontů přes modelové fosfolipidové membrány
Navrátil, Tomáš ; Šestáková, Ivana ; Mareček, Vladimír
Synthetically prepared model phospholipid bilayers (PLBs) in the form of black membranes, vesicles or supported membranes, with incorporated ionophores or real ion channels (i.e., artificially synthesized or gained from real living cells, e.g. protoplasts) are promising for study and simulations of transporting processes across the real cell membranes and the membranes surrounding sub-cellular structures. The electrochemical methods were found to be very suitable and sensitive enough for characterization of such processes.
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Patch Clamp Technique – The Tool for Ions Transport across Model and Real Biological Membranes
Navrátil, Tomáš ; Jaklová Dytrtová, J. ; Jakl, M. ; Šestáková, Ivana ; Mareček, Vladimír ; Krůšek, Jan
The project is aimed at the preparation and characterization of model and/or real phospholipid bilayers at stabilized phase boundaries enabling studies of transfer of charged and uncharged species between the two phases. The best way for investigation of inorganic ion transfer is provided by using mercury as one of the phases, in view of the large amount of the relevant electrochemical data available, whereas the transfer of more complex species is better studied in the system of an organic and an aqueous phase stabilized by (agar) gel. The results contribute to the understanding of ion transport across real membranes. Polypeptides and peptides capable forming ionic channels and enabling transport of various ions and molecules across the membranes, will be incorporated into the model membranes. The possibilities of transport of selected compounds across the model membrane will be investigated using cell permeable peptides as well.
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Ion beam analysis in material research
Bočan, Jiří ; Macková, Anna ; Malinský, Petr
In 2005, a new accelerator Tandetron 4130 MC produced by HVEE, The Netherlands, unique in the Czech Republic, was installed in the Laboratory of Nuclear Analytical Methods at the Nuclear Physics Institute. During the whole year 2006, construction and development of two beamlines and four experimental setups for the nuclear analytical methods proceeded. These methods namely are RBS (Rutherford Back-Scattering), TOF-ERDA (Elastic recoil detection analysis with time-of-flight measurement), ion implantation and RBS-channeling. The first three methods are presented in detail in this article.
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Ion beam analysis in material science
Macková, Anna ; Bočan, Jiří ; Malinský, Petr
In this paper we presented our results of complementary research using ion beam analysis for study of materials. Combination of RBS, PIXE and ERDA method enables us to characterize the elemental composition and the elemental depth profiles of complex multi-layer systems or study complicated difussion processes in different applications of material sciences. We described the newly installed methods TOF-ERDA and RBS-channeling and their application on material characterization and the results of testing of these methods at our workplace.
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New possibilities of nuclear analytical methods using accelerator Tandetron 4130 in Nuclear Physics Institute of ASCR
Macková, Anna
The new accelerator (unique in Czech Republic) makes realisable to fundamentally develop the present analytical possibility and to put on the new technique of material modification and synthesising of advanced materials and structures. We report on new analytical methods - RBS-channeling, ERDA-TOF, ion microprobe. These methods give us opportunity to study crystalline materials in interstitial positions, to achieve the lateral resolution less than 1 micrometer and the depth resolution better than 1 nm. New accelerator produces wide range of ion masses, so the ion implantation is very important material modification technique.
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