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Development of an ex vivo lung perfusion system focusing on the preservation of fresh animal lungs for experiments and storage
Mesíková, Klaudia ; Forjan, Mathias (oponent) ; Paštěka, Richard (vedoucí práce)
A mechanical combined lung model is a type of model used in human breathing simulation. The biggest currency of the model is a high similarity with the human lungs. In order to work with the animal lungs for a longer time and so follow the principles of the 3Rs, a perfusion system is involved in the procedure. The perfusion system filled with a chosen perfusate solution is responsible to prolong the period in which the animal lungs are viable for experiments and storage in the ex-vivo environment. The development of the properly functioning perfusion system is based on the several components included in the process. Choosing the right solution for the perfusion of the inner environment of the lungs is one of the most important things that need to be taken into account. The roller pump is considered the drive motor of the system. Pressure and flow sensors are responsible for monitoring the process parameters that could describe the functionality and the ability to preserve the animal lungs in the ex-vivo environment. The validation of the developed system by using the fresh animal lungs is a part of the thesis as well as the checking procedure of the solution’s influence with the time of the storage. The perfusion system was successfully created and tested. The pressure and flow parameters gained during the measurement were compared while using the saline solution, the Ringer’s solution, and Histofix in the system. The compliance parameter of the lungs were been monitored during the perfusion as well as during the storage with the aim to determine the behaviour of the preserved lungs with the time and the impact of the chosen solution on it. Compliance initially decreased and then stabilized at a certain value throughout the storage period. For the perfusion with the saline and Ringer’s solution, it dropped by one-third. For Histofix preservation, the drop was by half of the initial compliance. The preservation time without the presence of the tissue necrosis was 120 hours using the Saline solution, 240 hours using the Ringer’s solution, and at least 268 hours using Histofix. The perfusion system could further be used in medical research and make a positive aspect in terms of less consumption of the animal organs for experimental purposes in various fields of the research. For future research, the improvement of the perfusion system and solution composition to ensure even longer preservation is welcomed.
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Exploring the Population Characteristics of Direction-Selective Ganglion Cells Across the Retinal Space
Svatoň, Jan ; Paštěka, Richard (oponent) ; Jösch, Maximilian (vedoucí práce)
In the last century, substantial research has been dedicated to gaining an understanding of how visual information is encoded by neural populations and circuits. The overall picture that emerged from these efforts shows that visual information is first processed by intricate circuitries in the retina and subsequently relayed to higher brain structures. Both stages appear to have developed remarkably sophisticated computations. The functional study of these neuronal transformations has been examined either using electrophysiological or imaging techniques. In the retina, these techniques have limited the analysis of spatial specializations across the retina, either by the number of available electrodes (in electrophysiology) or the size of the field-of-view (FOV) (in imaging experiments). For example, simultaneous recordings of retinal ganglion cells (RGC) have been confined to an area (~ 200 x 200 um2) using state-of-the-art imaging techniques. In my thesis, I have explored a newly developed method that uses a FOV, which is 40-times larger in comparison with conventional optical methods, allowing me to overcome this technical limitation. This thesis uses this novel method to explore population characteristics of direction-selective ganglion cells (DSGCs) across the retinal space of mouse retinas. By recreating already known population patterns, we confirmed that our novel imaging method works. In addition, this thesis investigates the effects of adjuvants for enhanced global RGC infection rates that may potentially facilitate the unbiased recording of RGCs and introduces a novel stimulus for inspecting receptive fields (RFs) of RGCs. This novel stimulus outperforms conventional stimuli used in current studies in both the resolution of the yielded RF and the necessary time of stimulus presentation. It opens the door for following studies to describe for the first time the distribution patterns of RFs across the retinal space and to improve the clustering of cell classes.
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Modelling of flow and pressure characteristics in the model of the human upper respiratory tract under varying conditions
Karlíková, Adéla ; Forjan,, Mathias (oponent) ; Paštěka, Richard (vedoucí práce)
The aim of this master’s thesis is to create 3D model of upper respiratory tract (URT) according to the original model segmented from CT data, apply different conditions to the air flow inside the model, and afterwards, evaluate the change of characteristics of velocity and pressure. The model of URT was realized in the interface of Computational Fluid Dynamics software ANSYS and the Navier-Stokes equations were used for modeling the air flow inside the model. Firstly, simple 2D model was created for familiarization with the ANSYS interface. Furthermore, the 3D model of URT was constructed, and velocity and pressure characteristics were modeled under varying conditions. These conditions include different placement and quantity of sampling gaps within the model and choice of different combinations of inlets. Finally, the results are presented and evaluated along with the illustrations of the models modeled under varying conditions. The 3D model of URT means a compromise between computational load and model complexity and can be used as a basis for further research.
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Osciloskop v systému Android
Paštěka, Richard ; Balogh, Jaroslav (oponent) ; Sekora, Jiří (vedoucí práce)
Bakalářská práce se zabývá návrhem digitálního osciloskopu pomocí vývojové platformy Arduino Mega ADK. V teoretické části práce jsou rozebrány základní parametry digitálních osciloskopů, typy vzorkování a obecné vlastnosti A/D převodníků. Práce se dále zabývá popisem vývojové platformy Arduino Mega ADK. Praktická část práce popisuje jednotlivé kroky realizace osciloskopu. Od obecného návrhu přechází v konkrétní popis řešení softwaru a hardwaru. Software se skládá ze dvou navzájem komunikujících programů. První, program mikrokontroléru, obstarává akvizici dat. Druhý slouží k vykreslení měřených průběhů na obrazovku počítače. Hardware přeřazený platformě Arduino Mega ADK vhodně upravuje vstupní měřený signál pro účely měření. Ve výsledcích jsou zhodnoceny průběhy a parametry vytvořeného osciloskopu, které byly otestovány pomocí funkčního generátoru.
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Integration and testing of a real time processing unit for lung simulation
Paštěka, Richard ; Drauschke, Andreas (oponent) ; Sekora, Jiří (vedoucí práce)
An active mechanical lung simulator (iLung) provides the possibility of simulating human breathing patterns. The aim of this thesis is to implement and test an real time embedded control and acquisition system cRIO as iLung control unit. Resulting connections are documented in tables and also by labelling assembly drawings with corresponding pin functions. One of the major improvements was made by tuning the motor and modifying the proportional-integral controller in the software. Those modifications resulted in significantly reduced motor oscillations around zero value. In order to increase usability and accessibility of the simulator a user manual and corresponding laboratory experiment were additionally created. The Validation of cRIO implementation was not limited to simple testing routines, but also extended on testing the simulator as a whole functioning unit. The results of simulator based measurements were compared and discussed to the spirometry measurements, taken from 20 subjects. Measurements showed a high degree of similarity between breathing patterns simulated by iLung and normal human breathing supporting the possibility for further research applications.
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