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Evaluation of glutathione content in plants as a marker of heavy metals environmental contamination
Borková, Marie ; Stoupalová, Michaela (referee) ; Opatřilová,, Radka (advisor)
Dependence of glutathione concentration on the amount of thallium in the plant was studied. Observed plant was maize (Zea mays) which was divided to two parts – root and overground. Two culture procedures were elaborated where seeds and young seedlings were cultivated in a solution of thallium of concentration 0, 1, 3, 5, 8, a 10 µmol/l. Extraction agents used during extraction were phosphate buffer and solution of ascorbic acid. Determination of glutathione was realized by capillary electrophoresis (CE) and high performance liquid chromatography (HPLC). Diode array detector (DAD) was used in both methods. Quantification of the thallium amount in the plant was done by method of inductively coupled plasma-atomic emission spectrometry (ICP-AES).
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Study of behaviour of selected elements in soil profiles on the Alsar deposit, North Macedonia.
Fizková, Karolína ; Mihaljevič, Martin (advisor) ; Vaňková, Maria (referee)
This thesis is dealing with the behaviour and mobility of hazardous elements Tl, Hg and As occurring in anthropogenic soils on the heaps of the former Alshar deposit in North Macedonia. As, Sb and Au mining had been taking here since the 15th century, peaking during the 19th and first half of the 20th century. Local soils were thus created by periodic layering of tailings of varying age and origin. Nowadays, the area is known mainly for its large number of unique mineral phases, as well as for its extensive possibilities for soil contamination research. The contents of the elements in the samples were exceptionally high and without optimisation of measurement and appropriate dilution would exceed the upper limit of detection of the analytical methods. Arsenic and Tl occur on average in the tens to hundreds of mg/kg, while Hg occurs in the hundreds of mg/kg. The behaviour of the hazardous elements was assessed in relation to soil characteristics, including granulometry, pH, cation exchange capacity, total carbon and sulphur content, or content of Fe, Mn and Al oxides. Correlation with concentrations of other elements was also taken into account. In addition, an isotopic ratio of ε 205 Tl was determined for Tl in the selected samples. However, from the complete measurement results, it was very...
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Studium interakce adsorbátu s pasivovanými povrchy Si pomocí STM
Matvija, Peter ; Kocán, Pavel (advisor) ; Švec, Martin (referee)
The scanning tunneling microscopy is used to study the morphology of Tl adlayer in various stages of Tl desorption from the Si(111) surface and to study behaviour of various adsorbates on the Si(111)/Tl-(1 × 1). The utilization of thallium layer for passivation of the Si(111) was examined closely for various adsorbates. Manganese, aluminium, indium and tin layers which were directly deposited onto the Si(111)-(7 × 7) were compared with the layers prepared by deposition of adsorbate onto the passivating layer after the subsequent thermal desorption of Tl (after annealing at ≈ 400◦ C). Examined adsorbates exhibited signs of extremely high diffusivity and weak bond with the surface Si(111)/Tl- (1 × 1). The passivating layer was stable against the adsorbates.The application of thallium in the role of surfactant caused lowering of temperature and coverage needed for the preparation of reconstructions which were observed on the surfaces prepared by the direct deposition of adsorbate. 1
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Influence of Si surface passivation on growth and ordering of nanostructures
Matvija, Peter ; Kocán, Pavel (advisor) ; Rezek, Bohuslav (referee) ; de la Torre, Bruno (referee)
Silicon is currently the most widely used semiconductor material with applications ranging from solar cells and sensors to electronic devices. Surface functionalization of silicon with molecular monolayers can be used to tune properties of the material toward a desired application. However, site-specific adsorption of molecules or molecular patterning on silicon surfaces is a difficult task due to the high reactivity of silicon. In this work, we use scanning tunneling microscopy, ab-initio calculations and kinetic Monte Carlo simulations to study adsorption of organic molecules on a bare and thallium-passivated Si(111) surface. We show that the polarity of molecules has a large impact on bonding of the molecules with the bare surface. We demonstrate that, in comparison with the bare surface, molecules or single-atom adsorbates deposited on the Tl-passivated surface have significantly higher mobility. The increased mobility induces formation of 2D gases on the surface and enables formation of self-assembled molecular structures. We propose a novel method to directly visualize the 2D surface gases and we show that a phase of surface gases containing molecule-bound dipoles can be controlled by a non-homogeneous electric field. 1
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Interaction of adsorbates with passivated Si surfaces studied by STM
Matvija, Peter ; Kocán, Pavel (advisor)
The scanning tunneling microscopy is used to study the morphology of Tl adlayer in various stages of Tl desorption from the Si(111) surface and to study behaviour of various adsorbates on the Si(111)/Tl-(1 × 1). The utilization of thallium layer for passivation of the Si(111) was examined closely for various adsorbates. Manganese, aluminium, indium and tin layers which were directly deposited onto the Si(111)-(7 × 7) were compared with the layers prepared by deposition of adsorbate onto the passivating layer after the subsequent thermal desorption of Tl (after annealing at ≈ 400◦ C). Examined adsorbates exhibited signs of extremely high diffusivity and weak bond with the surface Si(111)/Tl- (1 × 1). The passivating layer was stable against the adsorbates.The application of thallium in the role of surfactant caused lowering of temperature and coverage needed for the preparation of reconstructions which were observed on the surfaces prepared by the direct deposition of adsorbate. 1
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Influence of Si surface passivation on growth and ordering of nanostructures
Matvija, Peter ; Kocán, Pavel (advisor) ; Rezek, Bohuslav (referee) ; de la Torre, Bruno (referee)
Silicon is currently the most widely used semiconductor material with applications ranging from solar cells and sensors to electronic devices. Surface functionalization of silicon with molecular monolayers can be used to tune properties of the material toward a desired application. However, site-specific adsorption of molecules or molecular patterning on silicon surfaces is a difficult task due to the high reactivity of silicon. In this work, we use scanning tunneling microscopy, ab-initio calculations and kinetic Monte Carlo simulations to study adsorption of organic molecules on a bare and thallium-passivated Si(111) surface. We show that the polarity of molecules has a large impact on bonding of the molecules with the bare surface. We demonstrate that, in comparison with the bare surface, molecules or single-atom adsorbates deposited on the Tl-passivated surface have significantly higher mobility. The increased mobility induces formation of 2D gases on the surface and enables formation of self-assembled molecular structures. We propose a novel method to directly visualize the 2D surface gases and we show that a phase of surface gases containing molecule-bound dipoles can be controlled by a non-homogeneous electric field. 1
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Studium interakce adsorbátu s pasivovanými povrchy Si pomocí STM
Matvija, Peter ; Kocán, Pavel (advisor) ; Švec, Martin (referee)
The scanning tunneling microscopy is used to study the morphology of Tl adlayer in various stages of Tl desorption from the Si(111) surface and to study behaviour of various adsorbates on the Si(111)/Tl-(1 × 1). The utilization of thallium layer for passivation of the Si(111) was examined closely for various adsorbates. Manganese, aluminium, indium and tin layers which were directly deposited onto the Si(111)-(7 × 7) were compared with the layers prepared by deposition of adsorbate onto the passivating layer after the subsequent thermal desorption of Tl (after annealing at ≈ 400◦ C). Examined adsorbates exhibited signs of extremely high diffusivity and weak bond with the surface Si(111)/Tl- (1 × 1). The passivating layer was stable against the adsorbates.The application of thallium in the role of surfactant caused lowering of temperature and coverage needed for the preparation of reconstructions which were observed on the surfaces prepared by the direct deposition of adsorbate. 1
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Interaction of adsorbates with passivated Si surfaces studied by STM
Matvija, Peter ; Kocán, Pavel (advisor)
The scanning tunneling microscopy is used to study the morphology of Tl adlayer in various stages of Tl desorption from the Si(111) surface and to study behaviour of various adsorbates on the Si(111)/Tl-(1 × 1). The utilization of thallium layer for passivation of the Si(111) was examined closely for various adsorbates. Manganese, aluminium, indium and tin layers which were directly deposited onto the Si(111)-(7 × 7) were compared with the layers prepared by deposition of adsorbate onto the passivating layer after the subsequent thermal desorption of Tl (after annealing at ≈ 400◦ C). Examined adsorbates exhibited signs of extremely high diffusivity and weak bond with the surface Si(111)/Tl- (1 × 1). The passivating layer was stable against the adsorbates.The application of thallium in the role of surfactant caused lowering of temperature and coverage needed for the preparation of reconstructions which were observed on the surfaces prepared by the direct deposition of adsorbate. 1
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Evaluation of glutathione content in plants as a marker of heavy metals environmental contamination
Borková, Marie ; Stoupalová, Michaela (referee) ; Opatřilová,, Radka (advisor)
Dependence of glutathione concentration on the amount of thallium in the plant was studied. Observed plant was maize (Zea mays) which was divided to two parts – root and overground. Two culture procedures were elaborated where seeds and young seedlings were cultivated in a solution of thallium of concentration 0, 1, 3, 5, 8, a 10 µmol/l. Extraction agents used during extraction were phosphate buffer and solution of ascorbic acid. Determination of glutathione was realized by capillary electrophoresis (CE) and high performance liquid chromatography (HPLC). Diode array detector (DAD) was used in both methods. Quantification of the thallium amount in the plant was done by method of inductively coupled plasma-atomic emission spectrometry (ICP-AES).
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Geochemical position of thallium in forest and agricultural soils.
DROZDOVÁ, Adéla
This M.Sc. thesis is focused on geochemical position of lithogenic and anthropogenic thallium in forest and agricultural soils. Two localities with different contamination source were chosen for this study. The first studied locality with occurrence of lithogenic thallium only, was an area of Kluky u Písku (South Bohemia). The second studied locality with anthropogenic thallium occurrence was the area of Olkusz (South Poland). The thallium fractionation forms in studied soils were detected by a sequential extraction procedure. The significant differences in thallium distribution and mobilization were observed at both localities. It was found that the erosive and bioturbation processes, as well as dust deposition into the soils, represent the main factors for lithogenic thallium mobilization and thallium distribution between biotic and abiotic components of the environment. Dust deposition of anthropogenic thallium depends mainly on predominant wind direction in landscape, or landform of target area (presence/absence of forest etc.). Ore processing methods and an inappropriate location of disposal sites also played an important role in the mobilization/imobilization process of anthropogenic Tl and soil contamination.
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