No description available.

No description available.

No description available.

Biomaterials may be any class of material that aids in the regeneration, replacement, or augmentation of damaged tissues. The design of biomaterials is becoming increasingly sophisticated as new technologies enable the manufacture and incorporation of smaller components and structural features. Thus, a demand for equally sophisticated tools and methods to study biomaterials are necessary. Two such tools are X-ray micro-computed tomography (micro-CT) and electron microscopy. Micro-CT has the advantage of imaging materials in 3D and non-destructively, but cannot reach the same resolving power as electron microscopy. However, electron microscopy has limited application with biomaterials due to destructive sample preparation requirements. The advantages and limitations of each imaging technique presents a complementary relationship between the two. This thesis aims to develop and apply a complementary workflow using X-ray and electron microscopy to investigate two diverse biomaterials: a titanium dental implant, and collagen tissue scaffold. In a pilot study, a 3D printed titanium dental implant with a novel dual-stemmed design was investigated for its biocompatibility in vivo. Dual-stemmed and conventional conical implants were inserted into the tibia of New Zealand White rabbits for 3 and 12 weeks, then retrieved with surrounding bone. The implants were analyzed using micro-CT, electron microscopy, and histology. Active bone growth and remodelling around the dual-stemmed implant at both time points was observed. Comparative bone-implant contact indicated the dual-stemmed implants supported bone-implant integration, and demonstrates the comparable biocompatibility of these 3D printed stemmed implants in rabbits up to 12 weeks. In a separate study, a gold functionalized collagen scaffold for tissue engineering applications has been developed. This scaffold design is intended for improved detection of scaffold degradation behaviour in vivo using X-ray CT. In this thesis, micro-CT and electron microscopy were used to analyze the resultant scaffold structure after fabrication, as it is important for understanding the outcomes of in vivo experiments. Imaging revealed a highly heterogeneous structure at both the micron and nanometer length scales. Interconnected pores from 50 – 400 μm made up 80% of the scaffold volume, while gold nanoparticles and agglomerates ranging from 16 – 1000 nm were non-uniformly dispersed at the nanoscale throughout the collagen matrix. This work highlights how complementary X-ray and electron microscopy can be applied to characterize diverse biomaterials during developmental and pre-clinical phases. / Thesis / Master of Applied Science (MASc) / The continued development of next generation biomedical materials, otherwise known as biomaterials, is in part dependant on the resources and technology that exist to drive manufacturing, characterization, and testing. Biomaterials are being designed and controlled at length scales smaller than the diameter of a single hair, and therefore specialized tools are required to accurately investigate and characterize these new designs. Two such tools are X-ray and electron microscopy, which can be used to image and understand three-dimensional biomaterials non-destructively, and with high resolution, respectively. However, both imaging techniques struggle to provide both. This thesis aims to develop and apply a complementary workflow using X-ray and electron microscopy to investigate two diverse biomaterials: a titanium dental implant, and collagen tissue scaffold, with high resolution, and in three dimensions.

Additive manufacturing (AM) technology is a key emerging field transforming how customized products with complex shapes are manufactured. AM is the process of layering materials to produce objects from three-dimensional (3D) models. AM technology can be used to print objects with complicated geometries and a broad range of material properties. However, the issue of ensuring the quality of printed products during the process remains an obstacle to industry-level adoption. Furthermore, the characteristics of AM processes typically involve complex process dynamics and interactions between machine parameters and desired qualities. The issues associated with quality assurance in AM processes underscore the need for research into smart quality assurance systems. To study the complex physics behind process interaction challenges in AM processes, this dissertation proposes the development of a data-driven smart quality assurance framework that incorporates in-process sensing and machine learning-based modeling by correlating the relationships among parameters, signatures, and quality. High-fidelity AM simulation data and the increasing use of sensors in AM processes help simulate and monitor the occurrence of defects during a process and open doors for data-driven approaches such as machine learning to make inferences about quality and predict possible failure consequences. To address the research gaps associated with quality assurance for AM processes, this dissertation proposes several data-driven approaches based on the design of experiments (DoE), forward prediction modeling, and an inverse design methodology. The proposed approaches were validated for AM processes such as fused filament fabrication (FFF) using polymer and hydrogel materials and laser powder bed fusion (LPBF) using common metal materials. The following three novel smart quality assurance systems based on a parameter–signature–quality (PSQ) framework are proposed: 1. A customized in-process sensing platform with a DOE-based process optimization approach was proposed to learn and optimize the relationships among process parameters, process signatures, and parts quality during bioprinting processes. This approach was applied to layer porosity quantification and quality assurance for polymer and hydrogel scaffold printing using an FFF process. 2. A data-driven surrogate model that can be informed using high-fidelity physical-based modeling was proposed to develop a parameter–signature–quality framework for the forward prediction problem of estimating the quality of metal additive-printed parts. The framework was applied to residual stress prediction for metal parts based on process parameters and thermal history with reheating effects simulated for the LPBF process. 3. Deep-ensemble-based neural networks with active learning for predicting and recommending a set of optimal process parameter values were developed to optimize optimal process parameter values for achieving the inverse design of desired mechanical responses of final built parts in metal AM processes with fewer training samples. The methodology was applied to metal AM process simulation in which the optimal process parameter values of multiple desired mechanical responses are recommended based on a smaller number of simulation samples. / Doctor of Philosophy / Additive manufacturing (AM) is the process of layering materials to produce objects from three-dimensional (3D) models. AM technology can be used to print objects with complicated geometries and a broad range of material properties. However, the issue of ensuring the quality of printed products during the process remains a challenge to industry-level adoption. Furthermore, the characteristics of AM processes typically involve complex process dynamics and interactions between machine parameters and the desired quality. The issues associated with quality assurance in AM processes underscore the need for research into smart quality assurance systems. To study the complex physics behind process interaction challenges in AM processes, this dissertation proposes a data-driven smart quality assurance framework that incorporates in-process sensing and machine-learning-based modeling by correlating the relationships among process parameters, sensor signatures, and parts quality. Several data-driven approaches based on the design of experiments (DoE), forward prediction modeling, and an inverse design methodology are proposed to address the research gaps associated with implementing a smart quality assurance system for AM processes. The proposed parameter–signature–quality (PSQ) framework was validated using bioprinting and metal AM processes for printing with polymer, hydrogel, and metal materials.

Cities involve several systems that work together as a network of urban relationships. These systems are in balance, and they work as a whole that articulates urban life. But what makes a city memorable and special are its events: those magical situations where the uniformity of the experience stops and something unique arise. Those are the moments where our memory is deeply engraved by a particular situation that will come back in our dreams and imaginative processes as an agent image. Four urban events — a space for film edition and writing, an urban stage, a footage archive and park, and a projection space- whose locations have been determined by a Cartesian game dictated by the Plan of Washington DC; and one common discipline, Film, will be the main focus of this research and a way of understanding the relations among Memory and its spaces, Architecture and Film in the City. Each event will respond to the particularities of its context by understanding first the sites and their relation with the city. These sites will be located in the four quadrants of Washington DC- NE, SE, SW and NW- and they will be consider as different communities that, by keeping their own idiosyncrasy, create one city. The question of urban scale as well as the concept of detail as part of an architectural cosmology will be present throughout the process of the thesis by the alternation of micro and macro analysis of each stage of the research. The question of scale will be present as well when comparing the four projects with their differences in shape and size. Characterization and monstrosity as architectural concepts will be incorporated into the project too, by understanding the role of Architecture in the city and what it wants to show or "monstrare" to its inhabitants. / Master of Architecture

El manuscrito versa sobre el desarrollo y caracterización de materiales híbridos basados en poliacrilato de hidroxietilo (a partir de ahora PHEA) reforzado por la inclusión de una fase amorfa de sílice. Ambas fases fueron sintetizadas simultáneamente: la fase orgánica se obtiene a través de una reacción de polimerización radicalaria inducida por la pequeña adición de un iniciador térmico (peróxido de benzoilo); además, la sílice (SiO2) fue polimerizada a través de una reacción sol-gel catalizada en medio ácido del alcóxido de silicio tetraetoxisilano (en adelante TEOS). Las condiciones del proceso sol-gel donde el retículo de dióxido de silicio se forma condicionan la estructura final de la sílice: grado de condensación, especies intermedias lineales frente a ramificadas, tamaños promedio, Algunos de los parámetros fundamentales que controlan la topología de la sílice en materiales compuestos derivados de reacciones sol-gel incluyen a la naturaleza del catalizador usado para aumentar la reactividad del alcóxido (así como su cantidad, pH), el agua disponible para hidrolizar al precursor de la sílice (referido a la cantidad estequiométrica necesaria para hidrolizar completamente a una molécula de TEOS) y la relación entre los porcentajes de las fases orgánica e inorgánica en el material híbrido final. El primer parámetro (el catalizador) y el segundo (el agua) se fijaron para de este modo sintetizar materiales con tamaños de sílice alrededor de las decenas de nanómetros (materiales nanocompuestos); el último de ellos, el ratio relativo entre las fases orgánica e inorgánica, se cambió sistemáticamente. Para caracterizar algunas propiedades físicas y químicas de los materiales nanocompuestos se utilizaron varias técnicas, entre las que se incluyen: microscopías, espectroscopía infrarroja, calorimetría, análisis dinámico mecánico, termogravimetría, hinchado en disolventes. / Rodríguez Hernández, JC. (2008). Acrylate-silica polymer nanocomposites obtained by sol-gel reactions. Structure, properties and scaffold preparation [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/3798

The increasing emergence of resistances against established antibiotics is a substantial threat to human health. The discovery of new compounds with potent antibiotic activity is thus of utmost importance. Within this work, we identify strong antibiotic activity of the natural product myxocoumarin B from Stigmatella aurantiaca MYX-030 against a range of clinically relevant bacterial pathogens, including clinical isolates of MRSA. A focused library of structural analogs was synthesized to explore initial structure-activity relationships and to identify equipotent myxocoumarin derivatives devoid of the natural nitro substituent to significantly streamline synthetic access. The cytotoxicity of the myxocoumarins as well as their potential to cure bacterial infections in vivo was established using a zebrafish model system. Our results reveal the exceptional antibiotic activity of the myxocoumarin scaffold and hence its potential for the development of novel antibiotics.

This scientific essay begins with three stories that portrays situations where different ways to view and understand the learning process of children in preschool. In the first two stories The Cakegame and Still life the aim is to describe how me, and my colleagues can have different perceptions on our role as preschool teachers. The purpose of the third story Have you done something fun today? is to present how daily interactions with the children’s guardians can create difficulties describing the process of teaching. Considering these differing views, I have, by reflecting, tried to figure out what it is that has brought on these individual perspectives. I have also looked at how the lacking of a common approach in how the teaching is carried out affects the children in questions. In the essay there is a common thread that to a great part is about the practical knowledge but also about the too varying view on children's learning in preschool, things that was revealed to me through my stories. The essay is also about how to compare between how I and other educators choose to support children in their learning through theoretical and practical knowledge but also through our own experiences and approaches. In this essay I will approach the concept of teaching and I will try to unravel what it means especially for myself, but also for other people that will in some way come in contact with the education system. I will compare the forthcoming pre-school curriculum with the current one to see if that will bring any answers to my questions. The theoretical perspectives I have analysed in relation to my own stories is based on concepts on preschool educators competencies described by researches Sonja Sheridan, Anette Sandberg and Pia Williams. A brief analysis about the concept of scaffold play has also been done, which refers to the supportive education while playing. The reflection is divided into two parts and are based on these two questions: How can the educator understand and interpret the learning assignment? as well as How can the educator describe and mediate the learning assignment? / Min vetenskapliga essä börjar med tre berättelser som gestaltar situationer där det framträder olika sätt att både se på, och förstå barns lärande i förskolan. I de första två berättelserna Tårtspelet och Stilleben vill jag beskriva händelser där jag och mina kollegor har skilda uppfattningar om våra roller som lärare i förskolan. I den tredje berättelsen Har ni gjort något roligt idag? vill jag visa på hur svårt det kan vara att i den dagliga kontakten med barnens vårdnadshavare beskriva undervisningsprocessen. Utifrån de skiftande synsätten har jag sedan, genom reflektion, försökt nysta i vad som bidragit till dessa enskilda perspektiv. Jag har även tittat på hur det påverkar barnen i verksamheten då det ofta saknas ett gemensamt förhållningssätt till hur undervisningen praktiseras. I texten framträder en röd tråd som handlar till stor del om praktisk kunskap men även om den alltför varierande syn på barns lärande i förskolan som jag fått syn på i mina berättelser. Den handlar också om att jämföra hur jag och andra pedagoger i förskolan kan stötta barnen i deras lärande genom teoretiska och praktiska kunskaper men också genom egna erfarenheter och förhållningssätt. I min essä närmar jag mig begreppet undervisning och försöker reda ut vad det kan betyda, framförallt för mig själv men även för andra människor som kommer i kontakt med förskolan. Jag jämför den kommande läroplanen med den nuvarande, för att se om den kan ge några svar på mina frågor. De teoretiska perspektiv jag undersökt i förhållande till mina berättelser utgår bland annat från några av de begrepp om förskollärares kompetenser som framlagts av forskarna Sonja Sheridan, Anette Sandberg och Pia Williams. Jag har även kortfattat tittat på begreppet scaffold play som handlar om stöttande undervisning i lek. Reflektionen är uppdelad i två delar utifrån mina frågeställningar; Hur kan pedagogen förstå och tolka lärandeuppdraget? samt Hur kan pedagogen beskriva och förmedla lärandeuppdraget?

Für das Tissue Engineering von Knochen werden poröse dreidimensionale Substrate (Scaffolds) als Zellträger benötigt, die in der vorliegenden Arbeit über keramische Technologie hergestellt wurden. Neben dem strukturierten und getrockneten Verbundwerkstoff (Grünkörper) und der Sinterkeramik wurde auch der Zwischenzustand nach Ausheizen der organischen Phase (Braunkörper) evaluiert. Bei der Herstellung blieb die Architektur der parallel orientierten Kanalporen, die über den Sol-Gel-Prozess der gerichteten ionotropen Gelbildung des Alginates erzeugt wurde, in allen Materialzuständen erhalten. Die Herstellungstechnologie wurde derart optimiert, dass die neuartigen anisotropen Scaffolds allen prinzipiell gestellten Forderungen für das Tissue Engineering entsprachen – sie waren porös mit weithin einstellbarer Porengröße, sterilisierbar, gut handhabbar unter Zellkulturbedingungen, biokompatibel und degradabel. Der unerwartete Favorit der Biomaterialentwicklung, der Braunkörper – eine nanokristalline, poröse Hydroxylapatit-Biokeramik – lag in einer ersten in vivo-Studie nach 4 Wochen integriert im Knochen vor. Die beobachtete Knochenneubildung deutete auf eine osteokonduktive Wirkung des Materials hin. Die in der vorliegenden Arbeit untersuchten Technologien und Biomaterialien bieten eine Basis für weitere Forschung und motivieren zur Weiterentwicklung und Nutzung als Scaffold für das Tissue Engineering oder Knochenersatzmaterial unter Verwendung der interessanten Architektur.