|
|
Studies of nanocrystalline silicon colloidal suspensions
Fučíková, Anna ; Valenta, Jan (advisor) ; Chaloupka, Roman (referee)
This diploma thesis deals with optical and biophysical properties of colloidal suspensions of porous nanocrystalline silicon (por-Si) in different media, conditions necessary to create por-Si with different luminescence peaks and their optical characterization (emission and excitation spectra). The lifetime excited state = (28,6±0,9) us on emission wavelength 600 nm for orange emitting por-Si is measured by the time resolved fluorescence. The behaviour of por-Si and grinded silicon (crystals of size about 1um) in biological environment (L929 mouse fibroblast) is studied with optical transmission microscopy, time-lapse microphotography of cell culture evolution, fluorescent microscopy, and scanning electron microscopy (SEM). Transmission pictures prove an aggregation in presence of por-Si in media. This aggregates are going to internal environment of cells. At high concentration of grinded silicon we see meronecrosis. Por-Si has had also mildly negative effect on evolution of cell culture at very high concentrations, but cells are viable and cell division proceeds normally - next cell generation shows normal behaviour. Fluorescence microscopy used on orange emitting por-Si shows that por-Si is concentrated probably on cell membranes and its presence in internal cell environment is also proved. SEM proved...
|
|
| |
|
| |
|
| |
|
| |
|
|
Study of transport proteins of the Nramp family
Surá, Lucie ; Chaloupka, Roman (advisor) ; Holoubek, Aleš (referee)
The Natural Resistance-Associated Macrophage Proteins (Nramp) form functionally conserved family of proton-dependent divalent metal ion transporters. In the present study, we investigated transport properties of a prokaryotic Nramp homolog - MntH transporter from Escherichia coli. H+ transport mediated by MntH was monitored in a bacterial model system using pH-sensitive green fluorescent protein (pHluorin). Our experimental conditions enabled us to observe an uncoupled H+ transport mediated by MntH. Uncoupled H+ flux had been previously described in eukaryotic Nramp proteins, nevertheless this is the first observation of this phenomenon in a prokaryotic homolog. We demonstrated that the uncoupled H+ transport is pH- and temperature- dependent. The uncoupled transport H+ is also affected by specific single-point mutations at functionally important residues Asp34, His211 and Asn401. The second part of the work focused on effect of different ions, which are not MntH substrates, on transport properties of MntH. It was shown that addition of excess calcium or magnesium resulted in increase of H+ transport induced by divalent metal ions, but on the other hand our data suggest that calcium inhibits uncoupled H+ transport.
|
|
| |
|
| |
|
|
Design of control of axis with linear motor
Chaloupka, Roman ; Bradáč, František (referee) ; Vetiška, Jan (advisor)
This thesis deals with construction, connection and control axis with linear motor. The beginning of thesis is focused on principle of functioning and characteristics of linear motors. The following part describes used components of axis, their mechanical configuration and electrical wiring. Further thesis deals with creating PLC program and user interface for control axis in TwinCAT system. In last part is dealing correct software settings of axis.
|
|
|
Comparison of sensors for temperature measurement
Chaloupka, Roman ; Pavlík, Jan (referee) ; Bilík, Martin (advisor)
This work deals with temperature sensors. Basic terms are defined at the beginning of work. The following are distribution, description of construction and principle of touch sensors with electrical output. Other touch sensors are marginally described. Further is described principle of pyrometry and contactless sensors. In conclusion, work contains practical example of contactless temperature measurement.
|
guest ::
RSS feed.