Biomimetic elastomeric poly(glycerol sebacate)-based scaffolds for adipose tissue engineering

In spite of recent progress in the field of adipose tissue engineering, the optimal adipose tissue scaffold still remains illusive and the tailoring of the structure and properties of tissue scaffolds according to adipose tissue were less explored or even neglected. Thus, synthetic poly(glycerol sebacate) (PGS)-based scaffolds and hydrogels which mimic the properties of adipose tissue were developed in this PhD project for potential application in adipose tissue engineering

Thermoresponsive, stretchable, biodegradable and biocompatible poly(glycerol sebacate)-based polyurethane hydrogels

Thermoresponsive, stretchable, biodegradable and biocompatible polyester-based polyurethane (PEU) hydrogels, based on poly(glycerol sebacate) pre-polymer and poly(ethylene glycol)s of different molecular masses were synthesized by a facile solvent-based two-step method. The chemical and physical characteristics of the PEU hydrogels are tunable, enabling the design of various negatively thermosensitive, mechanically stable and biodegradable systems. The PEU hydrogels demonstrate reversible responses to a change in medium temperature from 5 °C to 37 °C, with the swelling ratio at equilibrium varying from 499% to 12%. The hydrogels have a tensile Young’s modulus, ultimate tensile strength and elongation at break in the range of 0.02–0.20 MPa, 0.05–0.47 MPa and 426–623%, respectively, and show high stretchability and full shape recovery after compression. These are similar to the mechanical properties of adipose tissues. In vitro degradation tests show mass losses of 8.7–16.3% and 10.7–20.7% without and with the presence of lipase enzyme for 31 days, respectively. In vitro cell tests show clear evidence that some of the PEU hydrogels are suitable for culturing adipose-derived stem cells and dermal fibroblasts and hence for future soft tissue regeneration. The functionalities of the PEU hydrogels were also evaluated for potential applications in drug delivery, thermal actuation and ultralow power generation. The results demonstrate the versatility of these PEU hydrogels for a variety of biomedical and engineering application

Biomimetic poly(glycerol sebacate)/poly(L-lactic acid) blend scaffolds for adipose tissue engineering

Large three-dimensional poly(glycerol sebacate) (PGS)/poly(l-lactic acid) (PLLA) scaffolds with similar bulk mechanical properties to native low and high stress adapted adipose tissue were fabricated via a freeze-drying and a subsequent curing process. PGS/PLLA scaffolds containing 73 vol.% PGS were prepared using two different organic solvents, resulting in highly interconnected open-pore structures with porosities and pore sizes in the range of 91–92% and 109–141 μm, respectively. Scanning electron microscopic analysis indicated that the scaffolds featured different microstructure characteristics, depending on the organic solvent in use. The PGS/PLLA scaffolds had a tensile Young’s modulus of 0.030 MPa, tensile strength of 0.007 MPa, elongation at the maximum stress of 25% and full shape recovery capability upon release of the compressive load. In vitro degradation tests presented mass losses of 11–16% and 54–55% without and with the presence of lipase enzyme in 31 days, respectively. In vitro cell tests exhibited clear evidence that the PGS/PLLA scaffolds prepared with 1,4-dioxane as the solvent are suitable for culture of adipose derived stem cells. Compared to pristine PLLA scaffolds prepared with the same procedure, these scaffolds provided favourable porous microstructures, good hydrophilic characteristics, and appropriate mechanical properties for soft tissue applications, as well as enhanced scaffold cell penetration and tissue in-growth characteristics. This work demonstrates that the PGS/PLLA scaffolds have potential for applications in adipose tissue engineering

Spiritual formation and the nurturing of creative spirituality : a case study in Proverbs

The article is positioned in the interface between Old Testament scholarship and the discipline of spiritual direction of which spiritual formation is a component. The contribution that a Ricoeurian hermeneutic may make in unlocking the potential which an imaginal engagement with the book of Proverbs may hold for the discipline of spiritual formation was explored. Specifically three aspects of the text of Proverbs illustrated the creative process at work in the text, and how it converges with the concept of spiritual formation and the nurturing of creative spirituality. These aspects were, the development in Lady Wisdom’s discourses, the functional definition of the fear of Yahweh (illustrated from Proverbs 10:1–15:33), and the paradigmatic character of the book of Proverbs. INTRADISCIPLINARY AND/OR INTERDISCIPLINARY IMPLICATIONS : The research is positioned in the interface between Old Testament studies and Practical Theology. The research results in the enhancement of the interdisciplinary dialogue and interchange of resources between the named disciplines with regard to the interest in formation of persons that the biblical book of Proverbs and the discipline of spiritual formation shares.http://www.ve.org.zaam2016Old Testament Studie

Feedeng mixture bin

Tato diplomová práce se zabývá návrhem a konstrukcí zásobníku krmných směsí ve dvou variantách. Varianta 1: objem 53 m3, výsypný úhel 60°, varianta 2: objem 45 m3, výsypný úhel 45°. Podle parametrů zadání a odborné literatury byl vypracován návrh obou variant zásobníků krmných směsí. Dále byl proveden výpočet zatížení od větru, sněhu a síly působící na nosnou konstrukci zásobníku ve směru průjezdu. Výkresová dokumentace se skládá ze sestav varianty 1 a 2, vybraných svařovacích podsestav a detailů částí varianty 1 zásobníku krmných směsí.This diploma thesis deals with proposal and construction of feeding mixture bin in two variants. The variant No. 1 has a capacity 53m3 with hopper angle 60° and the variant No. 2 has a capacity 45m3 with hopper angle 45°. The proposal of both variants of feeding mixture bin was worked out according to parameters of assignment and technical literature. Further it was made a calculation of wind load, snow load and a power reacting on bearing structure of bin in direction of thoroughfare. Technical documentation consists of configurations variant No. 1 and 2, chosen welding subassemblies and details of parts of variant No. 1 of feeding mixture bin.

Design and construction of 3D printer

Tato bakalářská práce se zabývá návrhem a konstrukcí 3D tiskárny. Cílem práce je vytvořit levnou a spolehlivou 3D tiskárnu s velkým pracovním prostorem. Návrh tiskárny vychází z otevřeného komunitního projektu RepRap. Tiskárna by měla sloužit pro tisk jednoduchých, plastových, mechanických, prototypových dílů pro různé stroje, u kterých není vyžadována veliká přesnost. Rešeršní část práce poskytuje přehled o technologiích 3D tisku, o materiálech používaných pro 3D tisk, o typech používaných konstrukcí a o podpůrných softwarových prostředcích. Konstrukční část je zaměřena na popis použitých hardwarových komponent a na výběr vhodné elektroniky. Pro elektrickou část je navržena rozšiřující deska plošného spoje pro zapojení většího počtu řadičů krokových motorů. Součástí je postup pro získání a úpravu firmwaru. Závěrečná část se věnuje přípravě tiskárny pro tisk a následnou údržbu, dále se zabývá tvorbou výrobních dat z 3D modelů, a popisuje průběh tisku. Výsledkem je funkční 3D tiskárna, která je svoji kvalitou srovnatelná s podobnými komerčními 3D tiskárnami, které jsou určené pro domácí použití.This bachelor thesis deals with design and construction of 3D printer. The aim of the thesis is to create a cheap and reliable 3D printer with a large workspace. The design of the printer is based on the open community project RepRap. The printer should be used to print simple, plastic, mechanical, prototype parts for various machines that do not require high precision. The theoretical part of the thesis provides an overview about 3D printing technologies, materials used for 3D printing, types of structure used and about supporting software tools. The construction part is focused on describing used hardware components and on choosing suitable electronics. For the electric part is designed expanding PCB board for wiring more stepper motor drivers. It also includes a procedure for obtaining and modifying firmware. The final part focuses on preparing the printer for printing and subsequent maintenance, next it deals with the creation of manufacturing data from 3D models and it describe printing process. The result is a functional printer that is comparable to similar commercial 3D printers that is designed for home use

Feedeng mixture bin

This diploma thesis deals with proposal and construction of feeding mixture bin in two variants. The variant No. 1 has a capacity 53m3 with hopper angle 60° and the variant No. 2 has a capacity 45m3 with hopper angle 45°. The proposal of both variants of feeding mixture bin was worked out according to parameters of assignment and technical literature. Further it was made a calculation of wind load, snow load and a power reacting on bearing structure of bin in direction of thoroughfare. Technical documentation consists of configurations variant No. 1 and 2, chosen welding subassemblies and details of parts of variant No. 1 of feeding mixture bin

Inverse Pendulum Control

Tato diplomová práce se zabývá řízením jednoduchého inverzního kyvadla na vozíku a vytvořením konstrukce pro dvojité inverzní kyvadlo na vozíku. Cílem první části práce je vytvořit model inverzní kyvadla, navrhnout a otestovat dva různé způsoby řízení kyvadla v horním rovnovážném bodě včetně algoritmu pro vyšvihnutí. Pohybové rovnice jsou sestaveny pomocí Lagrangeových rovnic druhého druhu, z nich je následné stanoven nelineární a lineární stavový model, a simulační schéma, popsány jsou zde i různé modely tření. Hodnoty parametrů modelu jsou hledány pomocí numerické optimalizační úlohy. Udržení inverzního kyvadla v horním rovnovážném bodě je řešeno stavovým regulátorem a kaskádním řízením s dvěma PID regulátory. Parametry PID regulátorů jsou vyhledány pomocí nástroje PID Tuner v prostředí MATLAB a numerickou optimalizační úlohou. Parametry stavového regulátoru jsou stanoveny metodou umístění pólů, LQR a numerickou optimalizační úlohou, součástí je i nelineární pozorovatel úhlové rychlosti kyvadla. Algoritmus vyšvihnutí je založen na výpočtu energie kyvadla. Cílem druhé části práce je vytvoření simulačního modelu dvojitého inverzního kyvadla, a fyzické konstrukce dvojitého kyvadla, včetně bezdrátového měřícího modulu úhlu natočení druhého článku kyvadla. Dále jsou zde prozkoumány cíle a způsoby identifikace a řízení.This diploma thesis deals with the control of a single inverted pendulum on a cart and with the creation of a structure for a double inverted pendulum on a cart. The aim of the first part of the work is to create a model of the inverse pendulum, to design and test two different control methods of pendulum at the upper equilibrium point, including the algorithm for swing-up. The equations of motion are compiled using Lagrange equations of the second kind, from which a nonlinear and linear state space model and a simulation scheme are subsequently determined, various friction models are also described here. The values of the model parameters are found using a numerical optimization method. Maintaining the inverse pendulum at the upper equilibrium point is solved by a state space controller and cascade control with two PID regulators. The parameters of PID controllers are found using the PID Tuner tool in the MATLAB environment and using a numerical optimization method. The parameters of the state space controller are determined by the method of pole placement, LQR and numerical optimization method, a non-linear observer of the angular velocity of the pendulum is also a part of it. Swing-up algorithm is based on the calculation of the pendulum energy. The aim of the second part of the work is to create a simulation model of a double inverse pendulum, and the physical construction of a double pendulum, including a wireless measuring module of the angle of rotation for the second part of the pendu-lum. There are also researched targets and methods of identifying and controlling

Porous poly(vinyl alcohol)/sepiolite bone scaffolds: preparation, structure and mechanical properties

Porous poly(vinyl alcohol) (PVA)/sepiolite nanocomposite scaffolds containing 0-10 wt.% sepiolite were prepared by freeze-drying and thermally crosslinked with poly(arylic acid). The microstructure of the obtained scaffolds was characterised by scanning electron microscopy and micro computer tomography, which showed a ribbon and ladder like interconnected structure. The incorporation of sepiolite increased the mean pore size and porosity of the PVA scaffold as well as the degree of anisotropy due to its fibrous structure. The tensile strength, modulus and energy at break of the PVA solid material that constructed the scaffold were found to improve with additions of sepiolite by up to 104%, 331% and 22% for 6 wt.% clay. Such enhancements were attributed to the strong interactions between the PVA and sepiolite, the good dispersion of sepiolite nanofibres in the matrix and the intrinsic properties of the nanofibres. However, the tensile properties of the PVA scaffold deteriorated in the presence of sepiolite because of the higher porosity, pore size and degree of anisotropy. The PVA/sepiolite nanocomposite scaffold containing 6 wt.% sepiolite was characterized by an interconnected structure, a porosity of 89.5% and a mean pore size of 79 ?m and exhibited a tensile strength of 0.44 MPa and modulus of 14.9 MPa, which demonstrates potential for this type of materials to be further developed as bone scaffolds