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Development of endometrial fibrosis in the mare : factors involved in tissue remodelling and collagen depositionOddsdóttir, Charlotta January 2008 (has links)
Age-related degeneration of the equine endometrium is an established and important cause of fertility problems in thoroughbred mares, causing great loss to the industry. As a part of the age-related endometrial degeneration complex, an excessive deposition of collagen leading to endometrial fibrosis is particularly important due to the limitations it causes to uterine function. The consequences include reduced efficacy of uterine defence mechanisms and a decrease in the uterine capacity for foetal nutrition. Extensive research into the process of fibrosis in other organs has shown that this condition results from the malfunction of physiological tissue repair mechanisms. These mechanisms revolve around tissue fibroblasts that due to continuous stimulation secrete excessive amounts of collagen and inhibit the activation of factors essential to the normal collagen degradation occurring in scar resolution. Among these factors are the MMPs, an enzyme family with the ability to degrade extracellular matrix components such as collagen during the normal repair mechanisms following tissue injury. The malfunction in the regulation of these enzymes is important in the development of fibrosis in the liver and other organs. In this study it was demonstrated that MMPs are involved in the acute uterine inflammatory response and that they were secreted by infiltrating inflammatory cells. The cellular mechanisms observed during endometritis in normal mares were comparable to the normal repair mechanisms known to be altered in the fibrosis of other organs. These enzymes were present in equine foetal fluids, and their regulation may be important in the process of abortion and stillbirth. It was demonstrated that inbreeding may be correlated with increased deposition of endometrial collagen in a study population of the Icelandic horse breed even though this breed appears to exhibit less severe endometrial degeneration than what is known in lighter breeds. It is likely that genetic predisposition leads to the disruption of normally self-limiting inflammatory and repair mechanisms in the endometrium, resulting in constant activation of collagen synthesis by local and infiltrating cells. This thesis has shown that tissue repair mechanisms involving MMPs are likely to be involved in endometrial fibrosis in the mare. An inherent alteration in these mechanisms may play a role in the pathogenesis of this condition, and might arise due to genetic predisposition. Further understanding of the pathways leading to excess collagen amounts in the endometrium may produce preventative measures, and even therapeutic targets.
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A global bifurcation theorem for Darwinian matrix modelsMeissen, Emily P., Salau, Kehinde R., Cushing, Jim M. 09 May 2016 (has links)
Motivated by models from evolutionary population dynamics, we study a general class of nonlinear difference equations called matrix models. Under the assumption that the projection matrix is non-negative and irreducible, we prove a theorem that establishes the global existence of a continuum with positive equilibria that bifurcates from an extinction equilibrium at a value of a model parameter at which the extinction equilibrium destabilizes. We give criteria for the global shape of the continuum, including local direction of bifurcation and its relationship to the local stability of the bifurcating positive equilibria. We discuss a relationship between backward bifurcations and Allee effects. Illustrative examples are given
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Elucidating the Molecular Architecture of Cartilage by ProteomicsHsueh, Ming-Feng January 2015 (has links)
<p>Articular cartilage is a highly specialized avascular tissue and consists of chondrocytes and two major components, a collagen-rich framework and highly abundant proteoglycans. The chondrocyte morphology and extracellular matrix properties vary with the depth of cartilage. Some past studies have defined the zonal distribution of a broad range of cartilage proteins in different layers. Based on the variations within each layer, the extracellular matrix can be further distinguished to pericellular, territorial and interterritorial regions. However, most of these studies used guanidine-HCl extraction that leaves an unextracted residual with a substantial amount of collagen. The high abundance of anionic polysaccharide molecules from cartilage adversely affects the chromatographic separation. Scatter oriented chondrocytes only account for the small proportion of the whole tissue protein extraction. However, the density of the cell varies with depth of cartilage as well. Moreover, the physiological status may also altered the extracellular matrix properties. Therefore, a comprehensive strategy to solve all these difficulties are necessary to elucidate the molecular structure of cartilage. </p><p>In this study, we used quantitative and qualitative proteomic analysis to investigate various cartilage tissue processing protocols. We established a method for removing chondrocytes from cartilage sections that minimized matrix protein loss. Quantitative and qualitative proteomic analyses were used to evaluate different cartilage extraction methodologies. The addition of surfactant to guanidine-HCl extraction buffer improved protein solubility. Ultrafiltration removed interference from polysaccharides and salts. The different extraction methods yielded different protein profiles. For instance, an overwhelming number of collagen peptides were extracted by the in situ trypsin digestion method. However, as expected, proteoglycans were more abundant within the guanidine-HCl extraction. </p><p>Subsequently we applied these methods to extract cartilage sections from different cartilage layers (superficial, intermediate and deep), joint types (knee and hip), and disease states (healthy and osteoarthritic). We also utilized lase capture microscopy (LCM) to harvest cartilage sample from individual subregions (territorial and interterritorial regions). The results suggested that there is more unique proteins existed in the superficial layer. By removing the chondrocytes, we were able to identify more extracellular matrix proteins. The phenotyping of cartilage subregions provided the chance to precisely localize the protein distribution, such as clusterin protein. We observed that the guanidine-HCl extractability (guanidine-HCl/ guanidine-HCl + in situ digestion extracts) of cartilage proteins. Proteoglycans showed high extractability while collagen and non-collagenous proteins had lower extractability. We also observed that the extractability might differ with depth of cartilage and also disease states might alter the characters as well. </p><p>Laser capture microscopy provides us the access to the cartilage subregions in which only few studies have investigated because of the difficulties to separate them. We established the proteomic analysis compatible-protocol to prepare the cartilage section for LCM application. The results showed that most of the proteoglycans and other proteins were enriched in the interterritorial regions. Type III and VI collagens, and fibrillin-1 were enriched in the territorial regions. We demonstrated that this distribution difference also varied with depth of cartilage. The difference of protein abundance between subregions might be altered because of disease states. </p><p>Last we were looking for the post-transliational modification existed in these subregions of cartilage. Deamidation is one of the modification without the enzyme involved. Previous studies have showed that deamidation may accumulated in the tissue with low turnover rate. Our proteomic analysis results suggests that abundance of deamidated peptides also varied in different layers and subregions of cartilage. </p><p>We have developed the monoclonal antibody based immunoassay to quantify the deamidated cartilage oligomeric matrix protein within cartilage tissue from different joints (hip and knee) and disease states (healthy, para-lesion, and remote lesion). The results suggests that the highest concentration of deamidated COMP was identified in arthritic hip cartilage. </p><p>The results of this study generated several reliable protocols to perform cartilage matrix proteomic analysis and provided data on the cartilage matrix proteome, without confounding by intracellular proteins and an overwhelming abundance of collagens. The discovery results elucidated the molecular architecture of cartilage tissue at different joint sites and disease states. The similarities among these cartilages suggested a constitutive role of some proteins such as collagen, prolargin, biglycan and decorin. Differences in abundance or distribution patterns, for other proteins such as for cartilage oligomaric matrix protein, aggrecan and hyaluronan and proteoglycan link protein, point to intriguing biological difference by joint site and disease state. Decellularization and a combination of extraction methodologies provides a holistic approach in characterizing the cartilage extracellular matrix. Guanidine-HCl extractability is an important marker to characterize the statue of cartilage; however it has not been fully understand. The protein distributions in matrix subregions may also serve as an index to characterize the metabolic status of cartilage in different disease states. A large sample cohort will be necessary to elucidate these characters.</p> / Dissertation
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Electrochromic Polymer Devices: Active-Matrix Displays and Switchable PolarizersAndersson, Peter January 2006 (has links)
Major efforts have been spent during recent years in worldwide attempts to achieve an electronic paper technology; the common name for novel flexible displays utilizing substrates such as paper, plastics or thin metal sheets. Various kinds of technology are available that potentially will be used for an electronic paper, which differs from each other mainly with respect to the choice of active materials, substrates and manufacturing techniques. There are many applications for electronic paper technology, ranging from high-resolution displays used in electronic books to updateable large-area billboards. The latter suggests a novel electronic display function that could extend the utilization of cellulose-based paper, which is one of the most common materials ever produced by mankind, by using the paper as a thin and flexible carrier. The requirement for fast update speed in such large area applications would probably be a bit more relaxed compared to traditional display technologies, while low-power consumption and bi-stability are among the factors that should be further emphasized, together with the utilization of well-established printing techniques to enable low-cost manufacturing of the displays. The choice of active materials is therefore crucial in order to reach these objectives in reality and this paves the way for printable conjugated polymers with electrochromic properties. Chemical synthesis of these materials during the last decades has resulted in a vast variety of electrochromic polymers with custom-tailored functionality covering a broad range of optical absorption and electrical conductivities. This thesis review the studies done on the electrochemical switching of poly(3,4-ethylenedioxythiophene) (PEDOT). For this material both the electrical conductivity and the optical absorption is controlled by the oxidation state. Active matrix addressed displays that are printed on flexible substrates have been obtained by arranging electrochemical smart pixels, based on the combination of electrochemical transistors and electrochromic display cells, into cross-point matrices. The resulting polymer-based active-matrix displays are operated at low voltages and the same active material can be used in electrochemical transistors and conducting lines and in electrochromic display cells employing the electronic and the opto-electonic properties of the material, respectively. In addition to this, a switchable optical polarizer is briefly discussed. This is a device utilizing electrochromism of stretch-aligned polyaniline (PANI). The combination of two identical devices in a vertical architecture, orthogonally oriented with respect to each other, results in a filter in which the orientation of the polarized optical absorption is governed by the voltage polarity applied to the device. / Report code: LiU-TEK-LIC- 2006:18
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New Cutting Tool Concept For Cylinder BoringBrinnen, Mikael, Laggar, Gustaf January 2016 (has links)
This thesis describes the process and result of generating concepts for a new adjustable cutting tool with integrated components. It was conducted under a period of ten weeks at the department R&D Digital Machining at Sandvik Coromant, Sandviken. The focus of the thesis was to generate and evaluate different concepts using well known methods such as TRIZ Contradiction and 40 principles, SCAMPER, Wish and Wonder, Brainstorming, Weight Determination matrix and Pugh matrix. To catch up on the latest technologies and similar tools in the industry today a literature study was conducted which resulted in a requirement specification for the concept in accordance with expertise from Sandvik Coromant. The key problems to be solved were the demanding tolerances and precision together with high forces and the limited space in the tool body. The thesis resulted in a selected concept with chosen components to meet the demanding requirements. The concept is presented in a 3D CAD-model with description and necessary data. The conclusion includes recommendations to Sandvik Coromant to further develop the selected concept into a prototype so that physical test can be performed and lifespan of electronic components can be evaluated.
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Bird Chirps Annotation UsingTime-Frequency Domain AnalysisVundavalli, Suveen Kumar, Danthuluri, Sri Rama Srinivasa Varma January 2016 (has links)
There are around 10,426 bird species around the world. Recognizing the bird species for an untrained person is almost impossible either by watching or listening them. In order to identify the bird species from their sounds, there is a need for an application that can detect the bird species from its sound. Time-frequency domain analysis techniques are used to implement the application. We implemented two time-frequency domain feature extraction methods. In feature extraction, a signature matrix which consist of extracted features is created for bird sound signals. A database of signature matrix is created with bird chirps extracted features. We implemented two feature classification methods. They are auto-correlation feature classification method and reference difference feature classification method. An unknown bird chirp is compared with the database to detect the species name. The main aim of the research is to implement the time-frequency domain feature extraction method, create a signature matrix database, implement two feature classification methods and compare them. At last, bird species were identified in the research and the auto-correlation classification method detects the bird species better than the reference difference classification method.
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Matrix Model Analysis of a Coastal Northern California Subpopulation of the Western Snowy Plover (<em>Charadrius alexandrinus nivosus</em>)Stewart, Jaclyn Grace 01 January 2017 (has links)
Shorebirds are increasingly threatened by introduced predators, invasive grasses, and human disturbance. Matrix models can be used to predict population growth and assess management options. The Pacific coast population of the western snowy plover, Charadrius alexandrinus nivosus, is listed as threatened under the Endangered Species Act, largely due to high rates of nest predation. A matrix model for the entire Pacific coast metapopulation of western snowy plovers was published in 1999 by Nur et al., but population growth has not been comprehensively reassessed since, even after development of a recovery plan (USFWS 2007) and extensive management intervention. I built and analyzed a matrix model for one subpopulation of western snowy plovers previously considered a sink habitat—Recovery Unit 2 in northern California, comprising Humboldt, Mendocino, and Del Norte counties. Based on my model, growth rate (lambda) is 1.05—countering a previous finding that Recovery Unit 2 is a sink—compared to 1.036 for the Nur et al. (1999) metapopulation model. I found that sensitivities and elasticities for each vital rate were similar between the two models; adult survival had the greatest effect on lambda, followed by juvenile survival, and fecundity had the least effect. Even though fecundity was lower for my model than Nur et al.’s (1999), adult survival was higher, which had a larger impact on population growth. In terms of management strategies, predator control, habitat restoration, and restriction of human activity should continue as outlined in the recovery plan, so as to continue the trend of positive growth for the coastal breeding population. Future directions involve performing population viability analyses for other recovery units to reassess the state of western snowy plovers compared to 1999.
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Observation of CP violation in B+/- → DK+/- decaysGandini, Paolo January 2012 (has links)
An accurate determination of the angle γ of the Unitary Triangle is one of the most important goals of the LHCb experiment. The LHCb detector is a single-arm spectrometer at the LHC, optimised for beauty and charm flavour physics. As the angle γ is the least experimentally constrained parameter of the Unitary Triangle, its precise experimental determination can be used to test the validity of the Standard Model. The Unitary Triangle phase γ can be extracted in B → DK decays at tree-level, exploiting the interference between b → c(ūs) and b → u(c̄s) transitions. This interference is sensitive to γ and can give measurable charge asymmetries. In particular, γ ≠ 0 is required to produce direct CP violation in B decays and this is the only CP-violating mechanism for the decay of charged B<sup>±</sup> mesons. In this thesis, an analysis of CP violation in B<sup>±</sup> → DK<sup>±</sup> and B<sup>±</sup> → Dπ<sup>±</sup> decays is presented, where the D meson is reconstructed in the two-body final states: K<sup>±</sup>π<sup>∓</sup>, K<sup>+</sup>K<sup>−</sup>, π<sup>+</sup>π<sup>−</sup> and π<sup>±</sup>K<sup>∓</sup>. The analysis uses the full 2011 LHCb dataset of 1.0 fb<sup>-1</sup>, collected from pp collisions at √s = 7 TeV. Several CP-related quantities, e.g the ratio of B → DK and B → Dπ branching fractions and their charge asymmetries, are measured via a simultaneous fit to the invariant mass distributions of the modes considered. The suppressed B<sup>±</sup> → DK<sup>±</sup> mode is observed for the first time with ≈ 10σ significance. Once all measurements are combined, direct CP violation is established in B<sup>±</sup> decays with a total significance of 5.8σ.
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An Evaluation of Matrix Training Approaches for Teaching Compound Labels to ToddlersWilshire, Tayla C. 05 1900 (has links)
Matrix training techniques arrange instruction for stimulus relations that facilitate emergent responding to novel stimulus arrangements, which is a phenomenon known as recombinative generalization. The current study compared two common matrix training approaches, an overlapping (OV) design and a non-overlapping (NOV) design, with respect to arranging relations targeted for training. Two, typically-developing toddlers were taught compound action-object labels in either an OV or NOV matrix training design. Results suggest that an OV matrix design facilitates recombinative generalization more effectively than a NOV design.
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Econometric computing with HC and HAC covariance matrix estimatorsZeileis, Achim January 2004 (has links) (PDF)
Data described by econometric models typically contains autocorrelation and/or heteroskedasticity of unknown form and for inference in such models it is essential to use covariance matrix estimators that can consistently estimate the covariance of the model parameters. Hence, suitable heteroskedasticity-consistent (HC) and heteroskedasticity and autocorrelation consistent (HAC) estimators have been receiving attention in the econometric literature over the last 20 years. To apply these estimators in practice, an implementation is needed that preferably translates the conceptual properties of the underlying theoretical frameworks into computational tools. In this paper, such an implementation in the package sandwich in the R system for statistical computing is described and it is shown how the suggested functions provide reusable components that build on readily existing functionality and how they can be integrated easily into new inferential procedures or applications. The toolbox contained in sandwich is extremely flexible and comprehensive, including specific functions for the most important HC and HAC estimators from the econometric literature. Several real-world data sets are used to illustrate how the functionality can be integrated into applications. / Series: Research Report Series / Department of Statistics and Mathematics
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