National Repository of Grey Literature 133 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Electrochemical detection of prion proteins
Chepizhko, Veronika
This study is focused on different methods that allow to detect prion proteins (infectious proteins, causing a group of fatal neurogenerative diseases, affecting humans or other animals). In this research mice antigen and antibody, that are not infectious as prion proteins, were used as a model. The main research is based on electrochemical protein detection, using classical three-electrode impedance method. As a result, efficiency of this method was proofed, and appropriate concentration of antibody and antigen was found. This is important because knowing an appropriate concentration that is used in this method allows to get precise results, in the meantime, to use chemicals rationally.
A microfluidic platform for working with biological material
Vírostko, Ján ; Švarc, Vojtěch (referee) ; Hrdý, Radim (advisor)
Táto bakalárska práca sa zameriava na návrh a výrobu mikrofluidej platformy určenej pre lýzu buniek a ich následnú analýzu. Táto platforma by mala byť schopná efektívne mechanicky rezať bunky v preparátoch červených krviniek a následne ich analyzovať pomocou dvojelektródového elektrochemického systému. Teoretická časť tejto práce je zameraná na technológiu laboratória na čipe a používané komponenty v tejto technológií, ako napríklad mikrofluidné separátory, mixéry, komory určené na lýzu alebo mikroreaktory, ich aplikáciu a na koniec ich výrobu v čistých priestoroch. Taktiež je časť venovaná stručnej rozprave o fyzike prúdenia tekutín v mikroskopických kanáloch. Praktická časť tejto práce sa skladá z návrhu, výroby v čistých priestoroch a zapúzdrenia troch typov spomínanej platformy pomocou polymeru Parylene C. Následne je popísaná príprava zariadení na testovanie a ich následne testovanie. Na záver je uvedená dokumentácia výroby pomocou vytvárania snímkov s použitím elektrónového mikroskopu a grafické závislosti vypočítané počas charakterizácie elektród a snímky správania sa analytu v komore na lýzu.
Voltammetric Determination of 8-Hydroxy-5-nitroquinoline on a Silver Solid Amalgam Electrode
Bartůňková, Erika ; Vyskočil, Vlastimil (advisor) ; Fischer, Jan (referee)
This Bachelor Thesis is dedicated to the study of the electrochemically active substance 8-hydroxy-5-nitroquinoline. The stability of the prepared standard solution was monitored by UV/VIS spectrometry throughout the electrochemical measurements. A polished silver solid amalgam electrode was chosen as the working electrode. First, the optimum conditions for the measurements were determined by DC voltammetry and differential pulse voltammetry. The calibration dependence was subsequentlymeasuredbybothtechniquesintheconcentrationrangefrom1·10−7 to 1·10−5 mol/L. The DC voltammetry method was also used to measure the calibration dependence in model matrices of drinking and well water in the concetration order of 10−6 mol/L. To further investigate the electrochemical processes and controlling processes in the electrochemical transformation of 8-hydroxy-5-nitroquinoline, the cyclic voltammetry technique was used and applied at different polarization rates.
Voltammetric Determination of Warfarin at a Screen-Printed Carbon Electrode
Žužičová, Victória ; Vyskočil, Vlastimil (advisor) ; Dejmková, Hana (referee)
In this Bachelor Thesis, the electrochemical behaviour of the drug warfarin sodium was studied at a screen-printed carbon electrode (SPCE) using DC voltammetry (DCV) and differential pulse voltammetry (DPV). The dependence of the voltammetric behaviour of the substance on the pH of the medium was studied in Britton-Robinson buffer (BR buffer) in the pH range of 2.0−12.0. A pH of 7.0 was chosen as the optimum pH for both voltammetric techniques. A repeatability of 3.8% for DCV and 4.3% for DPV was determined for the selected pH. Calibration dependence was monitored under the selected optimal conditions in the concentration range 2∙10−6 to 1∙10−4 mol∙dm−3 . The limit of detection (LOD) was determined to be 1.05∙10−6 mol∙dm−3 for DCV and 2.59∙10−7 mol∙dm−3 for DPV. The limit of quantification (LOQ) was 3.50∙10−6 mol∙dm−3 for DCV and 8.62∙10−7 mol∙dm−3 for DPV. These newly developed methods were used for the determination of the active ingredient in the pharmaceutical formulation Warfarin Orion 5 mg. The values measured by voltammetric methods were compared with those obtained by spectrophotometric measurements. Key words Electrochemistry, Warfarin, Anticoagulants, Direct Current Voltammetry, Differential Pulse Voltammetry, Screen-Printed Carbon Electrode
Multiscale Modelling of Li-Ion Battery Volume Expansion
Mačák, M. ; Vyroubal, P.
Mechanical characteristics of Li-ion batteries play an important part in the design of electric devices or energy storage systems. Proper mechanical design can increase the safety and the longevity of devices. Apart from external forces, Li-ion batteries also experience internal volume changes due to inherent physical processes, especially volume changes caused by intercalation and deintercalation of lithium ions into electrode materials. Currently, these changes are mainly studied experimentally using complex methods, while numerical simulations of these processes are surprisingly rare. This works presents different numerical approaches for studying internal volume changes in Li-ion batteries. The results show that it is possible to study volume changes at different length scales, but it is necessary to apply a suitable simplification of the model to obtain macroscopic deformation.
Modified nucleotides and DNA for electrochemical labelling and defined display of small molecules
Krömer, Matouš ; Hocek, Michal (advisor) ; Křen, Vladimír (referee) ; Vrábel, Milan (referee)
This thesis is focused on enzymatic construction of DNA probes for electrochemical labelling, bioconjugations and, in the final part, building on knowledge gathered in previous chapters, it describes a method useful for construction of highly functionalized base-modified DNA enabling defined multivalent display of glycosides. In first chapter, a chemical route to diol-bearing nucleotides was found. Sonogashira reaction facilitated access to alkyne-tethered diols and subsequent catalytic hydrogenation, described for the first time in the literature, provided protection-free method for obtaining nucleotide diols tethered via flexible sp3 hybridized linker. Cleavage of alkane-linked, but not alkyne-linked, nucleotide diols yielded aliphatic nucleotide aldehyde. All nucleotides were found to be good substrates for KOD XL DNA polymerase in both primer extension and polymerase chain reaction, apart from aldehyde-linked dUCHO TP nucleotide, which performed well in PEX reaction, but gave PCR products only in a mixture with natural dTTP. This could be overcome by cleavage of diol-modified DNA, which also yielded aldehyde-functionalized dsDNA. All reactive probes were examined for bioconjugations with fluorescent hydrazine, reductive amination with lysine or lysine-containing peptides or other molecules...
Analytical approaches to study group interactions of azole pesticides with important biological active compounds
Kovač, Ishak ; Jaklová Dytrtová, Jana (advisor) ; Száková, Jiřina (referee) ; Navrátil, Tomáš (referee)
This dissertation presents a developed capillary electrophoresis method for analysing residues of triazole fungicides (TAF) from real samples ("Sweet cherry" tomato - Solanum lycopersicum L) and shows its potential application in environmental analysis. The developed method was validated in-house and characterised by a relatively short analysis time and low cost with sufficient LOD and LOQ. As an additional part of this dissertation, which rose from the tomato plants' treatment with TAF, we studied the impact of triazole fungicides on plant development and their impact on biologically active compounds. Determination of TAF residues from tomato peel carried out with capillary electrophoresis. Capillary electrophoresis is a versatile technique with minute amounts of sample required, with high efficiency in separating small molecules, such as selected TAF. The developed method, cyclodextrin-modified micellar electrokinetic chromatography, accomplished a baseline separation of the TAF mixture from tomato peel. The optimal conditions for separation were in the background electrolyte comprised of phosphoric acid and Tris (100 mM concentration, respectively), 20% v/v methanol, with apparent p[H+ ] 4.8. The constituents of the mixed micellar pseudo-stationary phase were ionic detergent sodium dodecyl...
Voltammetric Determination of 2,4-Dichlorophenoxyacetic Acid and 2,4-Dichlorophenol on a Screen-Printed Carbon Electrode
Jančová, Jana ; Vyskočil, Vlastimil (advisor) ; Fischer, Jan (referee)
The aim of the presented Master Thesis was to study an electrochemical behaviour of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP) resulting in the founding of optimum conditions for their voltammetric determination at a screen-printed carbon electrode (SPCE) using DC voltammetry (DCV) and differential pulse voltammetry (DPV). Voltammetric behaviour of both compounds was investigated in dependence on the pH of the medium (realized using Britton-Robinson buffer). The optimum pH for the voltammetric determination of 2,4-D on the SPCE was chosen to be pH 5,0 for both voltammetric techniques, and, for 2,4-DCP, it was chosen to be pH 6,0 for both voltammetric techniques. The determination of 2,4-D at a concentration of 1·10-4 μmol·L-1 showed good repeatability for both voltammetric techniques used (1.3% for DCV and 0.7% for DPV), and, for 2,4-DCP, it showed acceptable repeatability for both voltammetric techniques used (1.3% for DCV and 4.8% DPV). Under optimum conditions, the calibration dependence of 2,4-D was measured for DCV in the concentration range of 10-100 μmol·L-1 , with limit of quantification (LOQ) of 1.0 μmol·L-1 and limit of detection (LOD) 0.3 μmol·L-1 . Under optimum conditions, the calibration dependence of 2,4-D was measured for DPV in the concentration range...
The width of potential window of boron doped diamond electrodes in dependence on their pretreatment and composition of the mixed electrolyte solution
Dvořáková, Klára ; Schwarzová, Karolina (advisor) ; Dejmková, Hana (referee)
The diploma thesis focuses on the range of the potential window of the BDD electrode in dependence on the composition of the mixed electrolyte solution and the treatment of the electrode surface. The measurements were performed on a polished (p-BDD) and O-terminated (O-BDD) electrode by the method of linear sweep voltammetry (LSV) in a three-electrode system. It was confirmed that in an environment with a suitable organic solvent, the range of the potential window widens. The measured solutions consisted of deionized water containing sodium perchlorate with a concentration of 1 mmol l−1 and one organic solvent in which sodium perchlorate with a concentration of 1 mmol l−1 was also dissolved. Acetonitrile, methanol, N,N-dimethylformamide and isopropanol were used in solutions (0 %, 1 %, 5 %, 10 %, 50 %, 70 %, 90 %, 95 %, 99 % or 100 % volume percent). Expansion, or the shortening of the potential window range was evaluated separately for each solvent in the anodic and cathodic regions. The expansion of the window on both sides was confirmed in acetonitrile as the concentration of the solvent increases, so it is based on this experiment as a universal solvent suitable for the determination of reducing and oxidizing analytes, from measurements on O-BDD and also on p-BDD. In the case of the remaining...
Spectroelectrochemistry of 1,10-phenantrolines Substituted by Pyrrolidine and Phenothiazine Redox-active Units
Sokolová, Romana ; Wantulok, J. ; Fiedler, Jan ; Nycz, J. ; Degano, I.
Compounds based on 1,10-phenanthroline (Phen) and their complexes are used in many fields, such as a stabilizing agent in the synthesis of nanoparticles, catalysts in homogeneous catalysis and as a semiconductor in organic light-emitting diodes (OLED) due to their coordination abilities. In this work, 1,10-phenanthrolines functionalized by pyrrolidine and phenothiazine units were studied by electrochemical methods. Cyclic voltammetry resulted in several oxidation and reduction voltammetric peaks. Structure-activity relationship was investigated using in situ spectroeletrochemistry, spectrophotometry, infrared spectroscopy and chromatography.

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