This work describes the use of microfluidic technology and biomaterials in cancer research by mimicking the extracellular matrix (ECM) and development of drug delivery system. Initially, biomaterials such as Gelatin methacryloyl (GelMA) and collagen type I were combined to create a hydrogel composite able to mimic both healthy and cancerous ECM. The impact of the tumor microenvironment was analyzed by using the hydrogel inside of a pressurized microfluidic device and by tracking the movement of gold nanoparticles (GNPs). The GNPs showed a decrease in diffusion coefficient of 77% when analyzed in cancerous conditions. This investigation was further explored by analyzing the diffusion of charged GNPs in the same system, while also tracking cellular uptake. An inverse correlation between diffusion and cellular uptake was obtained for charged GNPs in breast cancer cells. Due to the tunable properties and biocompatibility of GelMA, this hydrogel was also employed in the development of pH-responsive drug delivery systems. Since GelMA contains a gelatin backbone, two responsive polymers (Polymers A and B) were synthesized. Microspheres of ~40 μm were fabricated in flow focusing microfluidic devices. Polymer A microspheres displayed a swelling increase of 167% in pH 6.0, while polymer B spheres showed a 296% swelling in pH 10. Considering the unique properties of the tumor microenvironment such as leaky vasculature and acid pH environment, polymer A was selected to be used in the production of nanocarriers. The behavior of this polymer in acidic environment illustrated its potential applicability as drug delivery systems to the tumor area. Polymer A nanogels displayed a uniform size of 74 ± 7 nm. Lastly, GNPs were added to the solution of polymer A, leading to the fabrication of GNPs-loaded nanogels, presenting a homogenous distribution of gold particles inside nanogels. / Graduate / 2023-07-05

No / The complexity of automotive systems has increased dramatically, driven by the requirement to address environmental and safety concerns and the pressure to offer higher level consumer technologies. This places a great challenge on product development organizations to manage the multidisciplinary systems integration in a reliable and robust manner. Engineering changes, which are integral part of the iterative automotive product development process, need to be managed in a way that efficiently addresses the integration requirements of complex multidisciplinary systems. The aim of this paper is to present a structured approach for engineering change management which is based on an enhanced interface analysis method which aims to identify comprehensively the system integration functional requirements as the basis for both engineering change prediction and support of robust engineering change design. The framework will be illustrated with an industrial case study on the development of an electric vehicle powertrain. The effectiveness of the proposed approach will be discussed in contrast with other methods for engineering change management.

Due to unique advantages of Jet Electrochemical Machining (Jet‐ECM) such as the absence of mechanical and thermal effects, there is an increasing demand for the implementation of the technology in industrial sectors. However, meeting the stringent quality requirements of the current technological level is a challenge in Jet‐ECM especially for complicated microstructures. Hence, the implementation of an adequate metrology system is necessary to minimise deviations and to enhance the process towards zero‐defect‐manufacturing. The metrology system should be capable of measuring the workpiece before machining in order to enable the machine to adjust the process parameters and to reach the desired micro‐structure. Post‐machining measurements to compare the machined part with the desired shape should be possible as well. This will enhance the machine to make corrections on the workpiece before delivery to the next section in a process chain. However, in order to reach the desired microstructures, the characteristics of workpiece like material properties and previously machined structures on the size and shape of the machined microstructure should be taken into consideration. This is done through the implementation of results of the fingerprint study into the process control. In this study the effects of previously machined single grooves which intersect the secondly machined groove on the size, shape and surface roughness are investigated. The previously machined groove was generated by milling or Jet‐ECM. Since at the intersections the gap size changes and this lead to changes in current and current density, it is expected to observe changes in size and surface roughness. This investigation will show how grooves change at the intersections and whether the mentioned changes are significant. Besides, some suggestions will be provided in order to minimise the effects in Jet‐ECM of intersecting single grooves.

Epithelial folding is an important morphogenetic process that is essential in transforming simple sheets of cells into complex three-dimensional tissues and organs during animal development (Davidson, 2012). Epithelial folding has been shown to rely on constriction forces generated by the apical actomyosin network (Martin et al., 2009; Roh-Johnson et al., 2012; Sawyer et al., 2010). However, the contributions of mechanical forces acting along lateral and basal cell surfaces to epithelial folding remain poorly understood. Here we combine live imaging with force measurements of epithelial mechanics to analyze the formation of two epithelial folds in the Drosophila larval wing imaginal disc. We show that these two neighboring folds form via two distinct mechanisms. These two folds are driven either by decrease of basal tension or increase of lateral tension, none of them depends on apical constriction. In the first fold, a local decrease in extracellular matrix (ECM) density in prefold cells results in a reduction of mechanical tension on the basal cell surface, leading to basal expansion and fold formation. Consistent with that, a local reduction of ECM by overexpression of Matrix metalloproteinase II is sufficient to induce ectopic folding. In the second fold a different mechanism is at place. Here basal tension is not different with neighboring cells, but pulsed dynamic F-actin accumulations along the lateral interface of prefold cells lead to increased lateral tension, which drives cell shortening along the apical-basal axis and fold formation. In this thesis I described two distinct mechanisms driving epithelial folding, both basal decrease and lateral increase in tension can generate similar morphological changes and promote epithelial folding in the Drosophila wing discs. / Die Faltung von Epithelien ist ein wichtiger morphogenetischer Prozess, der die Entstehung komplexer, dreidimensionaler Gewebe und Organe aus einfachen Zellschichten ermöglicht (Davidson, 2012). Es ist bekannt, dass Kräfte erzeugt durch das apikale Aktomyosin-Netzwerk wichtig sind für die erfolgreiche Faltung von Epithelien (Martin et al., 2009; Roh-Johnson et al., 2012; Sawyer et al., 2010). Die Rolle von mechanischen Kräften, die entlang der lateralen und basalen Seite wirken, ist jedoch kaum verstanden. Wir verbinden Lebendmikroskopie mit der Messung von mechanischen Eigenschaften, um die Entstehung von 2 Epithelfalten in den Imaginalscheiben von Drosophila zu verstehen. Wir können dadurch zeigen, dass die beiden Falten durch unterschiedliche Mechanismen entstehen. Sie entstehen entweder durch eine Verringerung der Spannung auf der basalen Seite oder durch eine Erhöhung der Spannung auf der lateralen Seite, aber keine von beiden entsteht durch zusammenziehende Kräfte auf der apikalen Seite. Die erste Falte entsteht durch eine lokale Verringerung der extrazellulären Matrix in den Vorläuferzellen, was zu einer Reduktion der Spannung auf der basalen Seite und zur Ausbildung der Falte führt. Die zweite Falte wird durch einen anderen Mechanismus ausgebildet. Hier ist nicht die Spannung auf der basalen Seite reduziert sondern dynamische Anreicherungen von F-Aktin auf der lateralen Seite resultieren in einer erhöhten lateralen Spannung, die zu einer Verkürzung der Zellen und damit zur Ausbildung einer Falte führt. In meiner Arbeit zeige ich 2 neue Mechanismen zur Entstehung von Epithelfalten auf, durch Absenken der Spannung auf der basalen oder Erhöhen auf der lateralen Seite.

[pt] Geralmente, em análises estatísticas, dados faltantes em ao menos uma variável resulta da completa eliminação da unidade respondente. Esta estratégia, padrão na maioria dos pacotes estatísticos, não produz resultados livres de viés, a não ser que os dados faltantes sejam Missing Completly At Random (MCAR). A tese mostra a classificação usada para o mecanismo gerador de dados faltantes e a modelagem de dados categóricos levando em conta os dados faltantes. Para isto, utiliza-se o modelo loglinear em combinação com o algoritmo EM (Expectation-Maximization). Esta combinação produz o algoritmo conhecido como ECM (Expectation-Conditional Maximization). A aplicação do método é feita com os dados do SAEB (Sistema Nacional de Avaliação da Educação Básica) para o ano de 1999, investigando a relação entre o responsável pelo desenvolvimento do projeto pedagógico na escola e o impacto na proficiência média da escola. / [en] Generally, in statiscal analysis, missing value in one variable at least, implies the elimination of the respondent unit. That strategy, default in the most of statistical softwares, don´t produce results free from bias, unless the missing data are Missing Completly At Random (MCAR). This dissertation shows the classification about the mechanisms that lead to missing data and the modeling of categorical data dealing with missing data. To do that we combine loglinear model and the EM (Expectation-Maximization)algorithm. This combination produce the agorithm called ECM (Expectation-Conditional Maximization) algorithm. The method is applied to SAEB educational data. The objective is to investigate the relationship between responsable for developing the pedagogic project and the impact on the mean proficiency of school.

Post-operative adhesion is a common complication after abdominal surgery, with high impact on patient wellbeing and healthcare costs. The repair of peritoneum is a complex process involving orderly phases which share some common features to normal wound healing. These include coagulation, infiltration of inflammatory cells, cell proliferation, extracellular matrix (ECM) deposition and remodelling, often with overlap between phases. The unique feature of peritoneal repair is that both small and large peritoneal wounds heal in a similar time. The peritoneum is a monolayer of elongated, flattened, squamous-like peritoneal mesothelial cells (PMC). Local mesothelial cell proliferation, centripetal cell migration from the wound edge, as well as incorporation of free-floating mesothelial cells may all contribute to repair of injured peritoneum. To date, the only well-characterised pathologic mechanism underlying post-operative adhesion formation at the molecular level is the formation of the fibrin layer and regulation of peritoneal fibrinolytic capacity. However, the contributions of collagen deposition and ECM remodelling to the peritoneal repair mechanism are not well understood. This thesis focuses on the role of PMC in the regulation of ECM deposition and remodelling in response to inflammatory stimuli in both in vivo and in vitro models, aiming to identify other key pro-fibrotic factors involved in the development of post-operative adhesion. We first identified that lysyl oxidase (LOX) played a key role in the progression of peritoneal fibrosis by regulating collagen cross-linking and deposition in vivo. The inhibition of LOX enzyme activity prevented the formation of fibrotic tissue by reducing collagen deposition. Meanwhile, dexamethasone (DEX) treatment also minimized the fibrotic response. Furthermore, in vitro studies showed that the induction of collagen deposition factors in PMC, including LOX and pro-collagen I, required both IL-1 and TGF-β signalling pathways. Thus, the combination of IL-1 + TGF-β was adopted in an in vitro model to mimic the inflammatory environment during peritoneal repair. Treatment of PMC with IL-1+TGF-β caused an epithelial-to-mesenchymal transition (EMT). These transformed PMC had enhanced cell motility and were more adherent to fibronectin. Finally, a real-time quantitative PCR-based microarray was used for genomic analysis of ECM-adhesion-related PMC genes in response to IL-1 and TGF-β treatment. The results showed that IL-1 was more involved in regulating ECM degradation by inducing expression of matrix metalloproteinase (MMP) genes, whereas TGF-β mainly affected genes involved in ECM deposition, including collagens and other ECM components. However, both cytokines were shown to regulate some key genes involved in the development of adhesion, including COL16A1, COL7A1, FN1, ITGA5, and TGFB1. Moreover, IL-1 was shown to reduce ITGA4 and ITGB6 expression affecting adherence of PMC to basement membrane, while TGF-β increased MMP14 and MMP16 expression, which could facilitate invasion of EMT-transformed PMC to the site of tissue repair. In summary, this thesis indicates that LOX plays an important role in peritoneal fibrosis. Secondly, a combination of IL-1 and TGF-β1 treatment demonstrates how these factors can act in concert to orchestrate tissue remodelling during peritoneal repair. Finally, genomic analysis of ECM-adhesion genes increases our understanding of aspects of the pathology of post-operative adhesion and identifies novel potential therapeutic targets to prevent adhesion formation.

The formation of the myelin sheath is a crucial step during development because it enables fast and efficient propagation of signals within the limited space of the mammalian central nervous system. During the process of myelination, oligodendrocytes actively interact with the extracellular matrix (ECM). These interactions are considered crucial for proper and timely completion of the myelin sheath. However, the exact regulatory circuits involved in the signaling events that occur between the ECM and oligodendrocytes are currently not fully understood. Therefore, in this dissertation we investigated the role of a known integrator of cell-ECM signaling, namely, focal adhesion kinase (FAK), during oligodendrocyte morphological maturation in vivo and in vitro. Conditional and inducible FAK-knockout mice (Fakflox/flox: PLP/CreERT mice) were generated to observe the effect of FAK loss on myelination in vivo. The role of FAK during post-migratory premyelinating oligodendrocyte morphological maturation was explored in vitro using primary rat oligodendrocyte cultures in combination with siRNA or inhibitor treatment. When inducing FAK knockout just prior to and during active myelination in vivo, we observed a significant reduction in the number of myelinated fibers following initial myelination. In addition, our data revealed a decreased number of primary processes extending from oligodendrocyte cell bodies at this stage of development under induction of FAK knockout. In contrast, myelination appeared normal on postnatal day 28. Our in vitro data demonstrated that reduction of FAK expression or activity affected the oligodendrocyte process network maturation in a way that is unique to the ECM substrate present. More specifically, our data suggest that FAK restrains the expansion of the oligodendrocyte process network in the presence of fibronectin and promotes expansion of the oligodendrocyte process network in the presence of laminin-2. We showed that the FAK-mediated restriction of oligodendrocyte morphological maturation is tightly developmentally regulated; being highly active during early stages of post-migratory premyelinating oligodendrocyte morphological maturation but greatly diminished at the later stages of oligodendrocyte development. Thus, our data suggest that FAK controls the efficiency and timing of CNS myelination during its initial stages, at least in part, by regulating oligodendrocyte process network morphological maturation.

I den här studien analyseras två lärarhandledningar till NTA-lådor inom teknik/fysik. NTA-lådorna har en blivit en stor del av skolans NO-undervisning utan att en kritisk granskning genomförts systematiskt. Lärarhandledningen granskas därför ur ett perspektiv för att se om det kan fungera som educational curriculum materials (ECM). Granskningen tar som utgångspunkt huruvida lärarhandledningen hjälper läraren att förutse och tolka elevers gensvar, utveckla lärarens ämneskunskaper, målreflektera i förhållande till lektionsinnehållet och synliggöra utvecklande pedagogiska idéer. Resultatet visar att till stora delar uppfylls inte kriterierna för ECM. Det betyder inte att NTA-lådan inte fungerar som läromedel utan mer att det finns en stor utvecklingspotential. För att få en mer övergripande bild skulle en mer omfattande analys, där övriga områden inom NTA analyseras, vara av intresse.

Plasminogen activator inhibitor-1 (PAI-1), a member of the serine protease inhibitor (serpin) superfamily of proteins, circulates in blood in a complex with vitronectin (VN). These two proteins are also found localized together in the extracellular matrix in many different pathophysiological conditions. Both of these proteins are involved with a number of physiologically important processes. Though PAI-1 is a well-known inhibitor of serine proteases, more emphasis is now geared towards its protease independent functions. VN, on the other hand, is a binding protein that exists in the circulation in a preferred monomeric conformation. However, in the extracellular matrix, VN exists as multimer with altered conformation. Though the exact reason for such conformational alterations and compartmentalization is unknown, there are a number of biomolecules, including PAI-1 that are proposed to cause such alterations. In last few years, sufficient experimental evidence has been gathered to confirm this protease- independent effect of PAI-1 by which it induces multimerization of VN in a concentration-dependent fashion. It has been observed also that PAI-1 remains associated with this multimeric complex for several hours. A major focus of this dissertation work was to extend our understanding of the mechanism of the interaction between these proteins and to explore the physiological relevance of the multimeric complexes formed by their interaction on cellular adhesion and migration. In our study, emphasis has been given to the presence of an appropriate microenvironment so that the role of the multimeric complexes could be investigated in a relevant biological setting. Our findings indicate the importance of the surrounding microenvironment in establishing the specific role of the VN/PAI-1 complex in cell-matrix interactions. In a previous study from our lab, it was found that vitronectin knock-out mice were more resistant to Candida infection compared to wild type C57Bl/6 mice. One of the goals of this dissertation work was to provide a mechanistic explanation for their increased survival of the vitronectin knock-out mice upon Candida infection. Another important aspect of this work was to establish biophysical methods for understanding the structural changes that happen in PAI-1 naturally or due to ligand binding.

Purchasing power parity (PPP) is considered as an important theory of explaining how exchange rate varies in the long run. Most of empirical studies in the past adapted linear cointegration method to test the purchasing power parity. However, there are papers point out that exchange rate exists non-linear cointegration and unexplainable bias might exist in testing the purchase power parity theory while using linear cointegration test. The methodology of this study is based on an application of ESTR ECM proposed by Kapetaniosetet al. to enhance the inadequate of linear cointegration test. We analyze the dynamic adjusting behavior of short-term nominal exchange rate with ESTR ECM model while the non-linear cointegratoin exists. The empirical result indicates that the purchase power parity between Taiwan and its major trading countries is confirmed. Among the trading countries, American, Japan and Hong Kong are suitable for using linear error correction model and non-linear error correction model for Singapore and Korea.