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Optimalization of printing methods of organic semiconducting layers preparation
Ehlich, Jiří ; Vala, Martin (referee) ; Salyk, Ota (advisor)
Electrophysiological biosensors enables a novel way to measure electrical activity of biological structures both in-vitro and in-vivo and represents valuable alternative to current cellular activity measuring methods. Within this work we will be focusing on development of organic semiconductor (PEDOT:PSS) based Organic Electrochemical Transistors (OECTs) and optimization of material printing methods used in their development. These transistors are meant to be able to transfer electrochemical signals within the cell membrane to electrical signal. Such sensors should be used for cytotoxicity testing of chemicals and potential drugs on cardiomyocytes. Main benefits of OECTs are in their higher sensitivity thanks to their ability to locally amplify electric signals, better noise-signal ratio and outstanding biocompatibility. Their development is undemanding and inexpensive due material printing methods and materials processable at room temperatures.
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Electrostimulation method for cardiomyocyte life extension
Čermáková, Adéla ; Ronzhina, Marina (referee) ; Čmiel, Vratislav (advisor)
This work deals with electrostimulation cardiomyocytes and design stimulation device for their cultivation and stimulation. First part of work deals with electrophysiological myocytes and the next problems with electrostimulation and preserved their original morphology and physiology structure. The following section is designed and constructed stimulation device to improve cell viability. Stimulation took place under different conditions and the success rate depends on the number of cells that survived.
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Evaluation of heart arrhythmias
Šromová, Michaela ; Kozumplík, Jiří (referee) ; Provazník, Ivo (advisor)
The thesis is a brief description of the anatomy and electrophysiology of the heart. The thesis also describes the different types of electrocardiogram and cardiac arrhythmias with a description of their treatment. The next section provides design of a programme for the classification of selected types of arrhythmias, and three options for rhythm detection, using the length of RR intervals, finding extremes of P and R waves, measuring the length of intervals and heights of amplitudes. The practical part of this work was to create a rhythm classifier assigning appropriate treatment of arrhythmias, verification of its functions on the signals available from the library of arrhythmias and its evaluation.
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Time-frequency analysis of electrograms
Doležal, Petr ; Ronzhina, Marina (referee) ; Kolářová, Jana (advisor)
This thesis deals with time-frequency analysis of electrograms measured on isolated guinea pig hearts perfused according to Langendorff. Time-frequency analysis is based on algorithms Matching Pursuit and Wigner-Ville Distribution. The theoretical part describes the basics of electrocardiography, measurement on isolated hearts, the theory of approximation method Matching Pursuit and its combination with the Wigner-Ville distribution spectrum showing the energy density of the signal. Also other common approaches of time-frequency analysis are presented including the theory of continuous wavelet transform. The presented algorithms were tested on a set of electrograms, on which were induced ischemia within measurement followed by reperfusion. The proposed method allows for the fast detection of ischemia without any a priori knowledge of the signal, and also serves as a tool for measurement of EG important points and intervals. In the conclusion efficacy of the method was presented and its possible uses has been discussed.
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Electrostimulation method for cardiomyocyte life extension
Čermáková, Adéla ; Smital, Lukáš (referee) ; Čmiel, Vratislav (advisor)
This work deals with the electrophysiology of cardiac cells, their electro-stimulation and design of stimulation device to extend their life. The first part is focused on the action potential in general, in muscle cells, followed by an analysis of the process and characteristics of the action potential in cardiomyocytes. The next section provides a procedure for isolating and process of changes that lead to cell death and of a method that the process would be eliminated. Part of this work is a program for processing and evaluation of pictures obtained during electro-stimulation process.
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Expert System for Assessing the Type of Arrhythmia during Catheter Radiofrequency Ablation of Cardiac Arrhythmias
Šromová, Michaela ; Provazník, Ivo (referee) ; Sekora, Jiří (advisor)
The theoretical part of the thesis contains a brief description of the anatomy and electrophysiology of the heart, as well as both, surface and intracardiac electrocardiograms. The thesis also describes the different types of cardiac tachycardias, their differential diagnosis and what is known as The Expert System. The practical section of the thesis notes and outlines the tree diagrams, and additionally describes various software solutions of The Expert System. Further, the thesis includes the classification of the heart rhythm, using The Expert System method with three typical tachycardia cases, and including a list of questions asked by The Expert System to the user. Answers to all questions asked are being assessed in the text, as well as illustrated in submitted examples of intracardiac ECG recordings. The Expert System has been verified during a series of catheterization procedures on 26 patients (where the evaluated cardiac rhythm was 34). The classication of the type of heart rhythm (per The Expert System) when comparing the results with the doctors coincided in 100 % of tested cases.
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Methods of measurement of electrical voltage on the cell membrane
DIVOKÝ, Karel
The aim of this work was to compile a comprehensive list of methods that deal with the research of voltage on the cell membrane. The work should help in orientation in these methods, as well as understanding of their physical and biological principle. In the first part is analysis of physical properties of membrane potential; in the second part are the most important methods for measuring membrane potential. Very important is the comparison of these methods in terms of their focus, localization, physical demands or in terms degree of damage of object under examination.
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Structural and Functional Study on Transient Receptor Potential Vanilloid 1 (TRPV1) and Ankyrin Receptor (TRPA1) Channels
SAMAD, Abdul
Investigations of structural and functional relationships of rat transient receptor potential cation channel, subfamily V, member 1 (TRPV1), also known as the capsaicin receptor, and human transient receptor potential cation channel, subfamily A, member 1, also known as TRPA1, are presented. Capsaicin induced Ca2+ -dependent desensitization of rat TRPV1 channel is studied and lead to the identification of key amino acid residues in the C- terminal domain of TRPV1 interacting with the membrane phospholipid PIP2 and an intradomain interaction that controls the open and desensitized state of the TRPV1 channel. Further the molecular basis of agonist AITC- and voltage-dependent gating on TRPA1 is explained. Hereby, residue P949 located near the center of the sixth transmembrane spanning helix (S6) is structurally required for normal functioning of the receptor and the distal bi-glycine G958XXXG962 motif controls its activation/deactivation properties. Furthermore, the gating region is extended towards the cytoplasmic part of the channel, putatively located near the inner mouth of the channel pore. A following series of experiments lead to the identification of a limited number of residues that appear important for allosteric regulation of the channel by chemical and voltage stimuli (K969, R975, K989, K1009, K1046, K1071, K1092 and K1099). In addition, three charge-neutralizing `gain-of- function{\crq} mutants (R975A, K988A, and K989A) which exhibited higher sensitivity to depolarizing voltages were characterized, indicating that these residues are directly involved in voltage-dependent modulation of TRPA1.
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