Polymer-zirconia based ceramic composites produced by 3D-printing

(English) Zirconia ceramic is widely used in numerous fields, such as electronics, machinery, and biomedical applications, due to its excellent properties as chemical resistance, thermal stability, electrical resistance, toughness, hardness, but also inertness and g biocompatibility. The 3D-printing technology has opened new doors for possible applications of zirconia and also allows for higher complexity of the shapes and structures, even for specimens with designed porosity, which would be until now unimaginable with traditional manufacturing methods like gel casting or cold isostatic pressing. The biocompatibility, inertness, and excellent aesthetic aspects of this ceramic make it also a preferred material for biomedical applications, more specifically in dentistry. However, application in the biomedical field has had some shortcomings, where the high hardness and brittleness of the material could cause discomfort or excessive wear. One of the aims of this thesis was to develop a new hybrid material that would complement the above-mentioned properties of zirconia and at the same time try to mimic the mechanical properties and biocompatibility of natural teeth using a combination of zirconia and acrylate polymer materials, while using additive manufacturing. The first part was focused on the development and manufacturing of such material. The idea of polymer-infiltrated ceramic networks (PICN), where a porous sintered ceramic structure is interpenetrated with a polymer matrix, was followed. The innovation of this technology was based on the 3D-printing of ceramic zirconia (3Y-TZP) scaffolds with designed porosity. After the optimization of the printing process, the 50% zirconia infill was chosen as the most appropriate porosity of the scaffold that was subsequently infiltrated with bisphenol A glycerolate dimethacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) copolymer. After the successful manufacturing of 3D-printed PICN and the proper infiltration of the copolymer, the physical-chemistry properties of the new material were characterized, as well as its mechanical properties. The bacterial adhesion was evaluated against Gram-negative Escherichia coli and Gram-positive Streptococcus salivarius bacteria lines, revealing, that although such samples do not have antimicrobial properties, they do not promote excessive bacterial growth either. Regarding biocompatibility, the cell assay using human osteoblasts (MG-63) was carried out showing good cell viability. To improve the antimicrobial properties of manufactured PICN, the surface was modified with the adhesion of silver nanoparticles, which were embedded in an enzymatically modified phenolated lignin matrix (Ag@PL NPs), obtained from renewable resources, to avoid metal particle oxidation. The functionalization of the surface of the hybrid material with such Ag NPs allowed the reduction of bacterial growth by 90% on the modified surface. The last part of this thesis focused on the improvement of osseointegration of zirconia surface in vitro. Although it is an inert material, surface modification is required to avoid possible failures of zirconia once implanted in vivo. A polydopamine methacrylate copolymer, which has proved antibiofilm formation properties, was applied to the surface of zirconia. Characterization of the surfaces has proven good viability of the MG-63 cell line and also a great adhesion of the polymeric nanofilm, produced by cold plasma to the surface of zirconia discs. Overall, this thesis describes the 3D printing of PICN structures, which have a macroporous structure for the correct infiltration of the copolymer. The synergy and good adhesion between these materials have given rise to a prototype whose mechanical properties simulate those for natural teeth(Español)La zirconia es un material ampliamente utilizado en electrónica y en la biomedicina debido a su estabilidad química, estabilidad térmica, resistencia eléctrica, dureza, alta tenacidad, y biocompatibilidad debido a su naturaleza inerte. Con el desarrollo de la tecnología de fabricación aditiva (o 3D-printing), se han propuesto nuevas aplicaciones para la zirconia hasta ahora inimagibles empleando métodos de producción convencionales. Con la fabricación 3D se consiguen estructuras más complejas, con geometrías más variables y con un mayor control de la de porosidad. Estas características convierten esta cerámica en uno de los materiales predilectos para aplicaciones biomédicas, especialmente en la odontología. No obstante, la dureza y fragilidad del material son dos limitaciones para su aplicación en la producción de biomateriales, debido a que pueden llevar al desgate de las estructuras y generar discomfort en el paciente. Uno de los objetivos de esta tesis fue el desarrollo por fabricación aditiva de nuevos materiales híbridos a base de zirconia y polímeros acrilatos para simular las propiedades mecánicas y la buena biocompatiblidad características de los dientes naturales. La primera parte estuvo enfocada en el desarrollo de dichos materiales, con la elaboración de redes cerámicas infiltradas por polímeros (PICN), en las cuales una estructura cerámica porosa sinterizada es interprenetada por una matriz de polímero. La innovación fue el diseæo de andamios de zirconia (3Y-TZP), impresas tridimensionalmente y con porosidad controlada y ajustada. Después de la optimización de impresión, se decidió trabajar con un porcentaje de relleno del 50 % de zirconia para obtener la porosidad adecuada de la matriz, que fue después infiltrada con dimetacrilato de glicerolato de bisfenol A y trietilenglicol dimetacrilato (Bis-GMA y TEGDMA).Tras la producción de las estructuras PICN y la infiltración del copolímero, los materiales generados fueron completamente caracterizados por técnicas físico-químicas y las propiedades mecánicas fueron analizadas. Ensayos de adhesión bacteriana fueron llevados a cabo con las bacterias Escherichia coli (Gram-negativa) y Stretoccocus salivarius (Gram-positiva) concluiendo que, a pesar de la ausencia de efecto antibacteriano del material híbrido, tampoco existe una promoción del crecimiento bacteriano en dicha superficie. Respecto a la biocompatibilidad, experimentos con la línea celular MG-63 mostraron altos porcentajes de viabilidad celular. Para mejorar las propiedades antimicrobianas de las PICN, la superficie fue modificada con nanopartículas de plata, las cuales fueron embebidas en una matriz de lignina modificada enziméticamente con fenolatos (Ag@PL NPs) para evitar su oxidación. La funcionalización de la superficie del material híbrido con dichas nanopartículas permitió reducir el crecimiento bacteriano en un 90 %, respecto a la superficie no modificada. La última parte de la tesis estuvo enfocada en realizar mejoras en la oseointegración de la zirconia in vitro. Apesar de que es un material inerte, funcionalización de su superficie es recommendable para evitar futuros rechazos de la zirconia una vez implantada in vivo. Un copolímero de metacrilato de polidopamina, el cual previene la formación de biopelículas bacterianas, fue escogido para recubrir la superficie de zirconia. La caracterización demostró una gran adhesión del nuevo polímero, generado por plasma frío, a la superficie plana de discos de zirconia, además de una buena viabilidad de las células de la línea MG-63, en principio atribuída a la presencia de la polidopamina. En conclusión, esta tesis describe el proceso de impresión 3D de estructuras PICN, las cuales tienen una estructura macroporosa para la correcta infiltración del copolímero. La sinergia y la buena adherencia entre estos distintos materiales ha dado origen a un prototipo cuyas propiedades mecánicas simulan aquellas descritas para los dientes naturales. Además, las modificaciones de la superficie de la zirconia (plana o en format 3D filamentoso) con el fin de mejorar las propiedades del composite, ha resultado sactisfactoria para profundizar dicha investigación en el campo odontológico, permitiendo nuevas vías para ampliar el espectro de aplicaciones de dichos materiales híbridos en otros campos biomédicos.Polímers i biopolímer

Inflammatory bowel disease (Problems of chronic Illnes)

Bakalářská práce se zaměřuje na klienty s chronickým onemocněním střev, a to Crohnovou chorobou a ulcerózní kolitidou. Práce je rozdělena na část teoretickou a výzkumnou. Teoretická část popisuje anatomii, historii, a charakteristiku obou nespecifických zánětů. Dále se zabývá kvalitou života chronicky nemocných. Ve výzkumné části jsou zpracovány a vyhodnoceny výsledky anonymního dotazníku, stanovení cílů a hypotéz. Práce je ukončena diskuzí a závěrem. Klíčová slova: Crohnova choroba ulcerózní kolitida kvalita života chronická nemoc klient respondentThis bachelor thesis is focused on the clients with chronic intestine disease that is Crohn disease and ulcer colitis.The thesis is divided into two parts - theoretical and practical. The theoretical part describes anatomy, history and characteristics features of the two non- specific disease. Second half of this part occupies with the quality of chronically ill person's life.The results of anonymous questionnare are arranged and later evaluated in the practical part as well as goals determination and hypotheses. At the end of bachelor thesis there are discussion and conclusion. Key words: Crohn disease ulcer colitis quality of life chronic Illnes client respondentInstitute of Theory and Practice of Nursing First Faculty of Medicine Charles University in PragueÚstav teorie a praxe ošetřovatelství 1. LF UK v PrazeFirst Faculty of Medicine1. lékařská fakult

Digital light processing-3D printing of thermoset materials with high biodegradability from amino acid-derived acrylamide monomers

Six acrylamide resins, derived from l-phenylalanine and l-leucine, are designed for application in digital light processing (DLP) printers to obtain biodegradable thermoset polymers. The acrylamide copolymers are prepared under light irradiation at 405 nm and thermal post-curing processes. Low molecular weight poly(ethylene glycol)diacrylate (PEGDA) and N,N-dimethylacrylamide (DMAM), both liquid resins, are used as co-monomers and diluents for the amino acid-derived acrylamide solubilization. The presence of two phenylalanine units and two ester groups in the acrylamide monomer accuses a fast degradation rate in hydrolytic medium in 90 days. The residual products leached in the aqueous media prove to be non-cytotoxic, when 3D-printed samples are cultured with osteoblast cells (MG63), which represents an advantage for the safe disposal of printer waste materials. The scaled-up pieces derived from l-phenylalanine and diethylene glycol, as amino acid-derived acrylamide (named compound C), PEGDA and DMAM, present high dimensional stability after DLP printing of complex structures used as testing samples. Layers of 50 µm of thickness are well cohesive having isotropic behavior, as demonstrated with tensile-strain measurements performed in X–Y–Z (plane) directions. The compound C, which contains phenylalanine amino acid, reveals a promising potential to replace non-biodegradable acrylate polymers used in prototyping systems.Postprint (author's final draft

Multifunctional City Hall, Bratislava-MČ Dúbravka, SK

Hodásová, V.: Víceúčelová městská hala, Bratislava-MČ Dúbravka, SK: Diplomová práce. Ostrava: VŠB- Technická univerzita, Ostrava, Fakulta stavební, Katedra architektury, 2019, Vedoucí práce: doc. Ing. arch. Ivan Gürtler, PhD. Diplomová práca sa zoberá v stanovenom rozsahu možnosťou vytvorenia „Malého centra“ Dúbravky, ktorého súčasťou je aj Viacúčelová športová hala. Cieľom je vytvoriť objekt, ktorý architektonicky, urbanisticky a funkčne doplní dané územie s rozvíjajúcou sa športovo-rekreačnou zónou, čím sa podporí súčasné využitie miesta, zároveň sa zvýši potenciál danej lokality a ponúkne nové možnosti jej využitia.Hodásová, V.: Multifunctional City Hall, Bratislava-MČ Dúbravka, SK: Diploma thesis. Ostrava: VŠB- Technical University of Ostrava, Faculty of Civil Engineering, Department of Architecture, 2019, Thesis head: doc. Ing. arch. Ivan Gürtler, PhD. Diploma thesis; in given amount; concerns with possibility of creation of ,,Little centre” Dúbravka which is connected with the more purposeful sporting hall. The aim is to create an architectonic, urban and functional object which is the addition of the specific area with the developed sporting-recreational zone. Actual using of the town will be supported by it. The potential of the concrete locality will also rise and offer new possibilities of using.226 - Katedra architekturyvýborn

Women in management

Tato bakalářská práce se zabývá problematikou zastoupení žen v managementu. Cílem práce je analýza postavení žen v managementu a bariér, se kterými ženy na manažerských pozicích během své kariéry přijdou do kontaktu. V teoretické části práce je obecně charakterizován management, osoba manažera, pojmy jako genderová diskriminace a gender pay gap. Dále je věnována pozornost objektivním a subjektivním bariérám kariérního postupu manažerek a zaměstnankyň s ambicí stát se manažerkami, a na závěr je statisticky shrnuta situace týkající se žen v managementu v České republice. V praktické části práce byl vyhotoven empirický výzkum formou kvalitativního výzkumu. Formou polostrukturovaných rozhovorů byly dotazovány manažerky ve vybrané firmě. Cílem provedeného výzkumu bylo zjistit, jak vnímají a jaké mají názory na postavení žen v managementu samotné manažerky.Táto bakalárska práca sa zaoberá problematikou zastúpenia žien v managemente. Cieľom práce je analýza postavenia žien v managemente a bariér, s ktorými ženy na manažérskych pozíciách počas svojej kariéry prídu do kontaktu. V teoretickej časti práce je všeobecne charakterizovaný management, osoba manažéra, pojmy ako genderová diskriminácia a gender pay gap. Ďalej je venovaná pozornosť objektívnym a subjektívnym bariéram kariérneho postupu manažérok a zamestnankýň s ambíciou stať sa manažérkami, a na záver je štatisticky zhrnutá situácia týkajúca sa žien v managemente v Českej republike. V praktickej časti práce bol vyhotovený empirický výskum formou kvalitatívneho výskumu. Formou pološtrukturovaných rozhovorov boli spytované manažérky vo vybranej firme. Cieľom prevedeného výskumu bolo zistiť ako vnímajú a aké majú názory na postavenie žien v managemente samotné manažérky.This bachelor thesis deals with the issue of representation of women in management. The aim of this thesis is to analyze the position of women in management and the barriers with which women will come into contact during their careers. In the theoretical part of the thesis management, manager as a person, gender discrimination and gender pay gap are generally characterized. Furthermore, attention is paid to the objective and subjective career advancement barriers of women managers and women employees with the ambition to become a manager. And finally, a statistically summarized situation regarding women in management in the Czech Republic is an ending to the first part. In the practical part of this thesis, an empirical research in the form of qualitative research was made. In the form of semi-structured interviews, managers in the selected company were questioned. The aim of the research was to find out how managers themselves perceive and what opinions they have on the position of women in management

Awareness of nearby people and their ability to care for the person with Alzheimer's dinase

Alzheimer's disease is an incurable brain condition, whose development can be only moderated. The consequences of Alzheimer's disease represent a serious problem from both health and economic point of view. As the disease is progressing, the patient loses his capacity to manage usual activities on his own and eventually becomes completely dependent on care of his relatives. This thesis focuses on the access to and the scale of information offered to family members of Alzheimer patients, as well as the available options of professional care. It is divided on theoretical and empirical part. In the theoretical part I describe dementia and its divisions, the concept of Alzheimer's disease, its symptoms, stages, development, treatment and prevention. Special attention is paid to changes in the life of patients and their families, patient's stay in a specialized sanatorium and the quality of its services. Moreover, an overview of suitable activities for Alzheimer patients is offered in this part. One of the chapters is dedicated to the Czech Alzheimer's Society which focuses on the long-term follow-up of the disease. Analyze the national strategic plans for Alzheimer's disease and similar diagnosis in the Czech Republic and Switzerland. Considering the nature of the analyzed topic I opted for the..

3D-Printed Polymer-Infiltrated Ceramic Network with Biocompatible Adhesive to Potentiate Dental Implant Applications

The aim of this work was to prepare and characterize polymer–ceramic composite material for dental applications, which must resist fracture and wear under extreme forces. It must also be compatible with the hostile environment of the oral cavity. The most common restorative and biocompatible copolymer, 2,2-bis(p-(2′-2-hydroxy-3′-methacryloxypropoxy)phenyl)propane and triethyleneglycol dimethacrylate, was combined with 3D-printed yttria-stabilized tetragonal zirconia scaffolds with a 50% infill. The proper scaffold deposition and morphology of samples with 50% zirconia infill were studied by means of X-ray computed microtomography and scanning electron microscopy. Samples that were infiltrated with copolymer were observed under compression stress, and the structure’s failure was recorded using an Infrared Vic 2DTM camera, in comparison with empty scaffolds. The biocompatibility of the composite material was ascertained with an MG-63 cell viability assay. The microtomography proves the homogeneous distribution of pores throughout the whole sample, whereas the presence of the biocompatible copolymer among the ceramic filaments, referred to as a polymer-infiltrated ceramic network (PICN), results in a safety “damper”, preventing crack propagation and securing the desired material flexibility, as observed by an infrared camera in real time. The study represents a challenge for future dental implant applications, demonstrating that it is possible to combine the fast robocasting of ceramic paste and covalent bonding of polymer adhesive for hybrid material stabilization