Dissertations / Theses: 'MLT circulation'

1

Muller, Lucas Omar. "Mathematical modelling and simulation of the human circulation with emphasis on the venous system: application to the CCSVI condition." Doctoral thesis, Università degli studi di Trento, 2014. https://hdl.handle.net/11572/367928.

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Recent advances in medical science regarding the role of the venous system in the development of neurological conditions has renewed the attention of researchers in this district of the cardiovascular system. The main goal of this thesis is to perform a theoretical study of Chronic CerebroSpinal Venous Insufficiency (CCSVI), a venous pathology that has been associated to Multiple Sclerosis. CCSVI is a condition in which main cerebral venous drainage pathways are obstructed. Its impact in cerebral hemodynamics and its connection to Multiple Sclerosis is subject of current debate in the medical community. In order to perform a credible study of the haemodynamical aspects of CCSVI, a sufficiently accurate mathematical model of the problem under investigation must be used. The venous system has not received the same attention as the arterial counterpart by the medical community. As a consequence, the mathematical modeling and numerical simulation of the venous system lies far behind that of the arterial system. The venous system is a low-pressure system, formed by very thin-walled vessels, if compared to arteries, that are likely to collapse under the action of gravitational or external forces. These properties set special requirements on the mathematical models and numerical schemes to be used. In this thesis we present a closed-loop multi-scale mathematical model of the cardiovascular system, where medium to large arteries and veins are represented as one-dimensional (1D) vessels, whereas the heart, the pulmonary circulation, capillary beds and intracranial pressure are modeled as lumped parameter models. A characteristic feature of our closed-loop model is the detailed description of head and neck veins. Due to the large inter-subject variability of the venous system, we perform a patient-specific characterization of major veins of the head and neck using MRI data collected in collaboration with the Magnetic Resonance Research Facility of the Wayne State University, Detroit (USA). Computational results are carefully validated using published data for the arterial system and most regions of the venous system. For head and neck veins validation is carried out through a detailed comparison of simulation results against patient-specific Phase-Contrast MRI flow quantification data. Regarding the development of novel numerical schemes, we construct high-order accurate, robust and efficient numerical schemes for 1D blood flow in elastic and viscoelastic vessels, as well as a solver for vessel networks. The solver is validated in the context of an in vitro network of vessels for which experimental and numerical results are available. After validation of both, the mathematical model and the numerical methodology, we use our theoretical tool to study the influence of different CCSVI patterns on cerebral hemodynamics. CCSVI patterns are defined by the medical literature as combinations of venous obstructions at different locations. Here we used two strategies. First, we take a venous configuration corresponding to a healthy control and explore the effect of different CCSVI patterns by modifying this network. Then, we characterize our venous network with the geometry of a real CCSVI patient and compare results with the ones obtained for the healthy control. The presented model provides a powerful tool to study still unresolved aspects of cerebral blood flow physiology, as well as several venous pathologies. Furthermore, it constitutes an ideal platform for improving currently used algorithms and for integrating fundamental physiological processes, such as detailed hemodynamics, regulatory mechanisms and transport of substances.

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2

Carroll, Dustin. "Modeling Circulation Dynamics and Submarine Melt in Greenland Fjords." Thesis, University of Oregon, 2017. http://hdl.handle.net/1794/22626.

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Meltwater accumulated on the Greenland Ice Sheet drains to glacier beds, discharging into fjords hundreds of meters below sea level. The injection of meltwater at depth generates an upwelling plume that entrains warm ocean water as it rises along the terminus, increasing submarine melt and driving a fjord-scale exchange flow. However, due to sparse ocean-glacier observations, we lack a process understanding of how plumes control fjord circulation and submarine melt. Combining numerical modeling, theory, and observations, this dissertation investigates near-glacier plume dynamics, the influence of glacier depth on plume structure and submarine melt, and the role of fjord-glacier geometry on circulation in tidewater glacier fjords. In Chapter II, I use buoyant plume theory and a nonhydrostatic, three-dimensional ocean–ice model to investigate the sensitivity of plume dynamics to subglacial discharge, turbulent diffusivity, and conduit geometry. Large discharges result in plumes with positive temperature and salinity anomalies in the upper water column. Fjord circulation is sensitive to conduit geometry; distributed subglacial discharge results in a stronger return flow of warm water toward the terminus. In Chapter III, I use buoyant plume theory, initialized with realistic ranges of subglacial discharge, glacier depth, and ocean stratification, to investigate how plume structure and submarine melt vary during summer months in 12 Greenland fjords. Grounding line depth is a primary control on plume-induced submarine melt: deep glaciers produce warm, salty subsurface plumes that undercut termini, and shallow glaciers produce cold, fresh surface-confined plumes that can overcut. Finally, in Chapter IV, I use regional-scale numerical ocean simulations to systematically evaluate how fjord circulation forced by subglacial plumes, tides, and wind stress depends on fjord width, glacier depth, and sill height. Glaciers grounded below sill depth can draw shelf waters over a shallow sill and into fjord basins with seasonal subglacial discharge; this process is independent of external shelf forcing. These results underscore the first-order effect that subglacial discharge and fjord-glacier geometry have in controlling fjord circulation and, thus, ocean heat flux to the ice. This dissertation includes previously published and co-authored material.

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3

Shah, Ajay M. (Ajay Mukesh). "Technologies for the isolation of circulating tumor cells." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/72916.

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Thesis (Ph. D. in Medical Engineering)--Harvard-MIT Program in Health Sciences and Technology, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 125-129).
Metastasis, the spread and growth of tumor cells from the primary site to distant organs, is arguably the most devastating and deadly attribute of cancer, and is ultimately responsible for 90% of cancer-related deaths. Circulating tumor cells (CTCs) are exceedingly rare cells found in the whole blood of cancer patients which have the potential to serve as a 'blood biopsy'. The intricate characterization of these cells could result in an entire new class of therapies directly targeting metastasis. Present technologies enable only a susbset of potential analyses to be conducted, principally due to sub-optimal cell isolation sensitivity, purity, throughput, or handling method. Here, we present two novel technologies to address the challenge of CTC isolation. First, we build on affinity-based microfluidic cell capture platforms by developing sacrificial hydrogel coatings to enable the innocuous release of captured cells; we demonstrate that model CTCs captured from whole blood remain viable and proliferative following release and are compatible with downstream immunostaining and FISH analysis. Second, we present a novel cell sorting system that interrogates over 10 million individual events each second, resulting in a high throughput, ultra-efficient rare cell sorter that delivers enriched cells in a vial, readily compatible with virtually any downstream assay. This is the first system combining the high sensitivity and single cell resolution that is characteristic of FACS with the practicality of MACS at a throughput and specificity afforded by inertial focusing, enabling operation in both 'positive selection' and 'negative depletion' modes. We find greater than 90% cell isolation efficiencies with over 2.5 log depletion of contaminating WBCs. Furthermore, the system is applied to clinical patient samples, and proof-of-concept is demonstrated in a cohort of breast, lung and prostate patients. Working in a negative depletion mode to isolate target cells in an unbiased fashion, we used the system to assess single putative CTCs isolated from an endogenous pancreatic mouse model for gene expression of tumor markers. Initial data confirms CTC heterogeneity at the single cell level, and positions us to move forward with single cell transcriptome sequencing, which may reveal a broad array of CTC phenotypes including metastatic precursors.
by Ajay Mukesh Shah.
Ph.D.in Medical Engineering

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4

Min, Changwook. "Miniaturized electromagnetic biosensors for circulating cancer biomarker detection." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113786.

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Thesis: Ph. D. in Biomedical Engineering, Harvard-MIT Program in Health Sciences and Technology, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 113-120).
Cancer is one of leading cause of deaths, and responsible for 8.2 million deaths worldwide. Especially, 70% of deaths from cancer occur in low or mid income countries. In order to deliver affordable and accessible cancer care to low income developing countries, it is critical to develop rapid, low cost, and highly accurate tools for cancer detection and treatment. Recently, liquid biopsy and circulating cancer biomarkers such as circulating tumor cells (CTC), extracellular vesicles (EV), and cell free DNA (cfDNA) have gained great attentions for early diagnosis, prognosis, and treatment monitoring of cancer patients because they can be accessed in less invasive approaches through body fluids while providing quantitative information about original tumors at low cost. To facilitate detection of circulating cancer biomarkers, we developed electromagnetic biosensing systems for rapid and quantitative molecular analysis. First, we report portable nuclear magnetic resonance (NMR) system that detects cancer cells or proteins labelled with magnetic nanoparticles (MNPs). The developed NMR system could detect as low as 20 cancer cells in 5 uL samples. Second, we describe micro-Hall magnetometer that molecularly profiles single cancer cell with magnetic multiplexing. The micro-Hall magnetometer, which consisted of an array of 7 um x 7 um Hall sensors, showed its capability to differentiate magnetic particles with distinct magnetic moments. We applied this technology to molecular profiling of single ovarian cancer cell. Last, we introduce wirelessly powered electrochemical system that detect cancer specific EV and DNA. Using immuno-magnetic sandwich assay, we could enrich almost 100% of EVs from clinical specimens without ultracentrifugation and profile cancer specific transmembrane proteins from as low as 105 EVs. Also, we demonstrated PCR-free detection of single stranded DNA with in-vitro protein synthesis assay. These electromagnetic biosensors will be powerful tools to deliver more accessible and affordable cancer care to resource limited areas in developing countries.
by Changwook Min.
Ph. D. in Biomedical Engineering

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5

Muller, Lucas Omar. "Mathematical modelling and simulation of the human circulation with emphasis on the venous system: application to the CCSVI condition." Doctoral thesis, University of Trento, 2014. http://eprints-phd.biblio.unitn.it/1184/1/Mueller_PhD.pdf.

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Recent advances in medical science regarding the role of the venous system in the development of neurological conditions has renewed the attention of researchers in this district of the cardiovascular system. The main goal of this thesis is to perform a theoretical study of Chronic CerebroSpinal Venous Insufficiency (CCSVI), a venous pathology that has been associated to Multiple Sclerosis. CCSVI is a condition in which main cerebral venous drainage pathways are obstructed. Its impact in cerebral hemodynamics and its connection to Multiple Sclerosis is subject of current debate in the medical community. In order to perform a credible study of the haemodynamical aspects of CCSVI, a sufficiently accurate mathematical model of the problem under investigation must be used. The venous system has not received the same attention as the arterial counterpart by the medical community. As a consequence, the mathematical modeling and numerical simulation of the venous system lies far behind that of the arterial system. The venous system is a low-pressure system, formed by very thin-walled vessels, if compared to arteries, that are likely to collapse under the action of gravitational or external forces. These properties set special requirements on the mathematical models and numerical schemes to be used. In this thesis we present a closed-loop multi-scale mathematical model of the cardiovascular system, where medium to large arteries and veins are represented as one-dimensional (1D) vessels, whereas the heart, the pulmonary circulation, capillary beds and intracranial pressure are modeled as lumped parameter models. A characteristic feature of our closed-loop model is the detailed description of head and neck veins. Due to the large inter-subject variability of the venous system, we perform a patient-specific characterization of major veins of the head and neck using MRI data collected in collaboration with the Magnetic Resonance Research Facility of the Wayne State University, Detroit (USA). Computational results are carefully validated using published data for the arterial system and most regions of the venous system. For head and neck veins validation is carried out through a detailed comparison of simulation results against patient-specific Phase-Contrast MRI flow quantification data. Regarding the development of novel numerical schemes, we construct high-order accurate, robust and efficient numerical schemes for 1D blood flow in elastic and viscoelastic vessels, as well as a solver for vessel networks. The solver is validated in the context of an in vitro network of vessels for which experimental and numerical results are available. After validation of both, the mathematical model and the numerical methodology, we use our theoretical tool to study the influence of different CCSVI patterns on cerebral hemodynamics. CCSVI patterns are defined by the medical literature as combinations of venous obstructions at different locations. Here we used two strategies. First, we take a venous configuration corresponding to a healthy control and explore the effect of different CCSVI patterns by modifying this network. Then, we characterize our venous network with the geometry of a real CCSVI patient and compare results with the ones obtained for the healthy control. The presented model provides a powerful tool to study still unresolved aspects of cerebral blood flow physiology, as well as several venous pathologies. Furthermore, it constitutes an ideal platform for improving currently used algorithms and for integrating fundamental physiological processes, such as detailed hemodynamics, regulatory mechanisms and transport of substances.

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6

Görgen, Klaus. "Sensitivitätsstudien und Analyse von Atmosphäre-Meereis-Wechselwirkungen mit dem regionalen Atmosphärenmodell HIRHAM4 auf Basis eines neu entwickelten beobachtungsgestützten unteren Modellantriebs während ausgewählter Sommer über der Arktis, Laptewsee = Sensitivity studies and analysis of atmosphere-sea-ice-interactions with the regional atmospheric model HIRHAM4 using a newly developed observational lower boundary forcing dataset during selected summers over the Arctic/Laptev Sea /." Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 2006. http://www.gbv.de/dms/bs/toc/517265761.pdf.

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7

Huff, Russell. "Melt anomalies on the Greenland Ice Sheet and large scale modes of atmospheric circulation." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3256466.

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8

Persson, Marie, Christina Ekerfelt, Jan Ernerudh, Leif Matthiesen, Maria Jenmalm, Yvonne Jonsson, Martina Sandberg, and Göran Berg. "Increased circulating paternal antigen-specific IFN-γ- and IL-4-secreting cells during pregnancy in allergic and non-allergic women." Linköpings universitet, Klinisk immunologi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-16134.

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INTRODUCTION: Allergic women have been reported to give birth to more children than non-allergic women, speculatively explained by the former's predisposition for Th2 polarization, possibly favoring pregnancy. AIM: The aim of this study was to test the hypothesis that allergy is associated with more Th2-deviated responses to paternal antigens throughout pregnancy. METHODS: Blood samples were collected on six occasions during pregnancy and two occasions postpartum (pp). Of the 86 women initially included, 54 women had a normal pregnancy and completed the sampling procedures. Eleven women fulfilled the strict criteria for allergy (allergic symptoms and circulating IgE antibodies to inhalant allergens) and 23 were strictly non-allergic (non-sensitized without symptoms). The numbers of blood mononuclear cells secreting IFN-gamma and IL-4, spontaneously and in response to paternal alloantigens, were compared between the groups. RESULTS: The numbers of spontaneously as well as paternal antigen-induced IFN-gamma- and IL-4-secreting cells were similar in allergic and non-allergic pregnant women on all occasions. A similar increase in the numbers of both IFN-gamma- and IL-4-secreting cells were found in allergic and non-allergic women during pregnancy, both regarding spontaneous and paternal antigen-induced secretion. CONCLUSIONS: This study does not support the hypothesis of a more pronounced Th2-deviation to paternal antigens in allergic pregnant women compared with non-allergic pregnant women, as measured by number of cytokine-secreting cells. The observed increase of both IFN-gamma- and IL-4-secreting cells during normal pregnancy may be interpreted as a Th2-situation, since the effects of IL-4 predominate over the effects of IFN-gamma.

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9

Polanski, Stefan. "Simulation der indischen Monsunzirkulation mit dem Regionalen Klimamodell HIRHAM." Phd thesis, Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2011/5250/.

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In dieser Arbeit wird das regionale Klimamodell HIRHAM mit einer horizontalen Auflösung von 50 km und 19 vertikalen Schichten erstmals auf den asiatischen Kontinent angewendet, um die indische Monsunzirkulation unter rezenten und paläoklimatischen Bedingungen zu simulieren. Das Integrationsgebiet des Modells erstreckt sich von etwa 0ºN - 50ºN und 42ºE - 110ºE und bedeckt dabei sowohl die hohe Topographie des Himalajas und Tibet Plateaus als auch den nördlichen Indischen Ozean. Das Ziel besteht in der Beschreibung der regionalen Kopplung zwischen der Monsunzirkulation und den orographischen sowie diabatischen Antriebsmechanismen. Eine 44-jährige Modellsimulation von 1958-2001, die am seitlichen und unteren Rand von ECMWF Reanalysen (ERA40) angetrieben wird, bildet die Grundlage für die Validierung der Modellergebnisse mit Beobachtungen auf der Basis von Stations- und Gitterdatensätzen. Der Fokus liegt dabei auf der atmosphärischen Zirkulation, der Temperatur und dem Niederschlag im Sommer- und Wintermonsun, wobei die Qualität des Modells sowohl in Bezug zur langfristigen und dekadischen Klimatologie als auch zur interannuellen Variabilität evaluiert wird. Im Zusammenhang mit einer realistischen Reproduktion der Modelltopographie kann für die Muster der Zirkulation und Temperatur eine gute Übereinstimmung zwischen Modell und Daten nachgewiesen werden. Der simulierte Niederschlag zeigt eine bessere Übereinstimmung mit einem hoch aufgelösten Gitterdatensatz über der Landoberfläche Zentralindiens und in den Hochgebirgsregionen, der den Vorteil des Regionalmodells gegenüber der antreibenden Reanalyse hervorhebt. In verschiedenen Fall- und Sensitivitätsstudien werden die wesentlichen Antriebsfaktoren des indischen Monsuns (Meeresoberflächentemperaturen, Stärke des winterlichen Sibirischen Hochs und Anomalien der Bodenfeuchte) untersucht. Die Ergebnisse machen deutlich, dass die Simulation dieser Mechanismen auch mit einem Regionalmodell sehr schwierig ist, da die Komplexität des Monsunsystems hochgradig nichtlinear ist und die vor allem subgridskalig wirkenden Prozesse im Modell noch nicht ausreichend parametrisiert und verstanden sind. Ein paläoklimatisches Experiment für eine 44-jährige Zeitscheibe im mittleren Holozän (etwa 6000 Jahre vor heute), die am Rand von einer globalen ECHAM5 Simulation angetrieben wird, zeigt markante Veränderungen in der Intensität des Monsuns durch die unterschiedliche solare Einstrahlung, die wiederum Einflüsse auf die SST, die Zirkulation und damit auf die Niederschlagsmuster hat.
In this study the regional climate model HIRHAM with a horizontal resolution of 50 km and 19 vertical levels is applied over the Asian continent to simulate the Indian monsoon circulation under present-day and past conditions. The integration domain extends from 0ºN - 50ºN and 42ºE - 110ºE and covers the high topography of Himalayas and Tibetan Plateau as well as the northern Indian Ocean. The main objective is the description of the regional coupling between monsoon circulation and orographic as well as thermal driving mechanisms of monsoon. A 44-years long simulation from 1958-2001, driven at the lateral and lower boundaries by European reanalysis (ERA40), is the basis for the validation of model results with observations based on station and gridded data sets. The focus is on the the long-term and decadal summer and winter monsoon climatology and its variability concerning atmospheric circulation, temperature and precipitation. The results successfully reproduce the observations due to a realistic simulation of topographic features. The simulated precipitation shows a better agreement with a high-resolution gridded data set over the central land areas of India and in the higher elevated Tibetan and Himalayan regions than ERA40. In different case and sensitivity studies the main driving mechanisms of the Indian monsoon (Sea Surface Temperatures, strength of the Siberian High in winter and soil moisture anomalies) are investigated. The results show, that the simulation of these mechanisms with a regional climate model is also difficult related to the complex non linear monsoon system and the small-scale processes, which are not just sufficiently parameterized and understood in the model. A paleoclimatic experiment for a 44-years long time slice in mid-holocene (6000 years before present), which is driven by a global ECHAM5 simulation, shows significant changes in the monsoon intensity due to the different solar forcing, which influences the SST, the circulation and the precipitation.

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10

Dansereau, Véronique. "Ice shelf-ocean interactions in a general circulation model : melt-rate modulation due to mean flow and tidal currents." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/78549.

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Thesis (S.M.)--Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 121-123).
Interactions between the ocean circulation in sub-ice shelf cavities and the overlying ice shelf have received considerable attention in the context of observed changes in flow speeds of marine ice sheets around Antarctica. Modeling these interactions requires parameterizing the turbulent boundary layer processes to infer melt rates from the oceanic state at the ice-ocean interface. Here we explore two such parameterizations in the context of the MIT ocean general circulation model coupled to the z-coordinates ice shelf cavity model of Losch (2008). We investigate both idealized ice shelf cavity geometries as well as a realistic cavity under Pine Island Ice Shelf (PIIS), West Antarctica. Our starting point is a three-equation melt rate parameterization implemented by Losch (2008), which is based on the work of Hellmer and Olbers (1989). In this form, the transfer coefficients for calculating heat and freshwater fluxes are independent of frictional turbulence induced by the proximity of the moving ocean to the fixed ice interface. More recently, Holland and Jenkins (1999) have proposed a parameterization in which the transfer coefficients do depend on the ocean-induced turbulence and are directly coupled to the speed of currents in the ocean mixed layer underneath the ice shelf through a quadratic drag formulation and a bulk drag coefficient. The melt rate parameterization in the MITgcm is augmented to account for this velocity dependence. First, the effect of the augmented formulation is investigated in terms of its impact on melt rates as well as on its feedback on the wider sub-ice shelf circulation. We find that, over a wide range of drag coefficients, velocity-dependent melt rates are more strongly constrained by the distribution of mixed layer currents than by the temperature gradient between the shelf base and underlying ocean, as opposed to velocity-independent melt rates. This leads to large differences in melt rate patterns under PIIS when including versus not including the velocity dependence. In a second time, the modulating effects of tidal currents on melting at the base of PIIS are examined. We find that the temporal variability of velocity-dependent melt rates under tidal forcing is greater than that of velocity-independent melt rates. Our experiments suggest that because tidal currents under PIIS are weak and buoyancy fluxes are strong, tidal mixing is negligible and tidal rectification is restricted to very steep bathymetric features, such as the ice shelf front. Nonetheless, strong tidally-rectified currents at the ice shelf front significantly increase ablation rates there when the formulation of the transfer coefficients includes the velocity dependence. The enhanced melting then feedbacks positively on the rectified currents, which are susceptible to insulate the cavity interior from changes in open ocean conditions.
by Véronique Dansereau.
S.M.

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11

Brand, Sascha. "Klimavariabilität der Tropo- und Stratosphäre in einem globalen gekoppelten Atmosphäre-Ozean-Modell mit vereinfachter stratosphärischer Chemie." Phd thesis, Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2008/1660/.

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In dieser Arbeit wurde die Variabilität der Atmosphäre in einem neuen gekoppelten Klimamodell (ECHO-GiSP) untersucht, welches eine vereinfachte Stratosphärenchemie (bis 80 km Höhe) enthält. Es wurden 2 Simulationen über 150 Jahre durchgeführt. In einer der Simulationen wurde die atmosphärische Chemie modelliert, hatte aber keinen Einfluß auf die Dynamik des Klimamodelles. In der zweiten Simulation wurde hingegen die Wirkung der Chemie auf die Klimadynamik explizit berücksichtigt, die über die Strahlungsbilanz des Modelles erfolgt. Dies ist die erste Langzeitsimulation mit einem voll gekoppelten globalen Klimamodell mit interaktiver Chemie. Die Simulation mit rückgekoppelter Chemie zeigt eine Abschwächung des atmosphärischen Variabilitätsmusters der Arktischen Oszillation (AO). Zudem kommt es in der Troposphäre zu einer Reduzierung der mittleren Windgeschwindigkeiten der gemäßigten Breiten aufgrund verringerter Temperaturgegensätze zwischen den Tropen und den Polargebieten. Auch in der Stratosphäre ergibt sich eine Abschwächung und Erwärmung des Polarwirbels. Diese Auswirkungen der Kopplung zwischen der atmosphärischen Chemie und der Dynamik des Klimamodelles sind eine wichtige Erkenntnis, da in früheren Klimasimulationen die Variabilität der AO oft zu stark ausgeprägt war. In der Stratosphäre reduziert sich infolge des abgeschwächten Polarwirbels auch die großräumige Zirkulation zwischen den beiden Hemisphären der Erde. In der Troposphäre werden hingegen die allgemeine Zirkulation, und damit auch die subtropischen Strahlströme des Windes verstärkt. Zudem kommt es in den Tropen zu Temperaturänderungen durch stratosphärische Ozonschwankungen in Abhängigkeit von der AO. Allgemein verändert sich die Kopplung zwischen Troposphäre und Stratosphäre, einschließlich des durch die Anregung von langen atmosphärischen Wellen erfolgenden vertikalen Energieübertrages aus der Troposphäre in die Stratosphäre.
In this work the atmospheric variability in a new coupled climate model (ECHO-GiSP) was analyzed, which includes a simplified stratospheric chemistry (up to 80 km height). Two simulations of 150 years were performed. In one of those simulations the atmospheric chemistry was modeled without having any influence back on the model dynamics. In the second simulation the impact of the chemistry on climate dynamics, taking place via the models radiation balance, was explicitly recognized. This is the first long term simulation using a fully coupled global climate model with interactive chemistry. The simulation with interactive chemistry shows a weakening of the Arctic Oscillation (AO) pattern of atmospheric variability. At the same time there is a reduction of the mean wind speeds in middle latitudes in the troposphere, which is caused by weaker temperature gradients between the tropics and the polar regions. Also, in the stratosphere a weakening and warming of the polar vortex is obvious. These effects of the coupling between atmospheric chemistry and the dynamics of the climate model are an important result, since in earlier climate simulations the variability of the AO often was overestimated. Due to the weakened polar vortex in the stratosphere also the large scale interhemispheric mean circulation is reduced. On the other hand, the tropospheric meridional mean circulation, and thus also the subtropical jetstreams of the zonal wind are enhanced. Furthermore there are tropical temperature variations in the troposphere and lower stratosphere, which are induced by stratospheric ozone variations associated to the phase of the AO. Generally, the coupling between tropo- and stratosphere is changed, which includes the vertical energy and momentum transfer by ascending planetary waves from the troposphere to the stratosphere.

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Moura, Jos? Edson de. "Influ?ncia dos modelos digitais de terreno na modelagem de circula??o hidrodin?mica 2DH: um estudo de caso." Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15969.

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Digital Elevation Models (DEM) are numerical representations of a portion of the earth surface. Among several factors which affect the quality of a DEM, it should be emphasized the attention on the input data and the choice of the interpolating algorithm. On the other hand, several numerical models are used nowadays to characterize nearshore hydrodynamics and morphological changes in coastal areas, whose validation is based on field data collection. Independent on the complexity of the physical processes which are modeled, little attention has been given to the intrinsic bathymetric interpolation built within the numerical models of the specific application. Therefore, this study aims to investigate and to quantify the influence of the bathymetry, as obtained by a DEM, on the hydrodynamic circulation model at a coastal stretch, off the coast of the State of Rio Grande do Norte, Northeast Brazil. This coastal region is characterized by strong hydrodynamic and littoral processes, resulting in a very dynamic morphology with shallow coastal bathymetry. Important economic activities, such as oil exploitation and production, fisheries, salt ponds, shrimp farms and tourism, also bring impacts upon the local ecosystems and influence themselves the local hydrodynamics. This fact makes the region one of the most important for the development of the State, but also enhances the possibility of serious environmental accidents. As a hydrodynamic model, SisBaHiA? - Environmental Hydrodynamics System ( Sistema B?sico de Hidrodin?mica Ambiental ) was chosen, for it has been successfully employed at several locations along the Brazilian coast. This model was developed at the Coastal and Oceanographical Engineering Group of the Ocean Engineering Program at the Federal University of Rio de Janeiro. Several interpolating methods were tested for the construction of the DEM, namely Natural Neighbor, Kriging, Triangulation with Linear Interpolation, Inverse Distance to a Power, Nearest Neighbor, and Minimum Curvature, all implemented within the software Surfer?. The bathymetry which was used as reference for the DEM was obtained from nautical charts provided by the Brazilian Hydrographic Service of the Brazilian Navy and from a field survey conducted in 2005. Changes in flow velocity and free surface elevation were evaluated under three aspects: a spatial vision along three profiles perpendicular to the coast and one profile longitudinal to the coast as shown; a temporal vision from three central nodes of the grid during 30 days; a hodograph analysis of components of speed in U and V, by different tidal cycles. Small, but negligible, variations in sea surface elevation were identified. However, the differences in flow and direction of velocities were significant, depending on the DEM
Os modelos digitais de terreno (MDT) consistem na representa??o matem?tica computacional da distribui??o de um fen?meno espacial que ocorre dentro de uma regi?o da superf?cie terrestre. A qualidade da representa??o do MDT est? influenciada, dentre outros fatores, pela origem do dado e pelo algoritmo interpolador utilizado. A caracteriza??o da circula??o hidrodin?mica ? um dos estudos com apelo ambiental que se utiliza dos MDTs como dado de entrada e, independentemente da complexidade dos processos representados nos modelos num?ricos, pode ter a qualidade de seus resultados dependente da capacidade de reprodu??o do MDT usado para representar a batimetria da ?rea de interesse. Sendo assim, o objetivo deste estudo ? avaliar a influ?ncia de batimetrias obtidas de diversos MDTs, nos padr?es de circula??o hidrodin?mica via modelagem num?rica. Para tanto, considerou-se os dados referentes ? regi?o costeira do nordeste do Brasil, correspondente ao litoral setentrional do estado do Rio Grande do Norte, frontal aos munic?pios de Macau, Guamar? e Galinhos. Essa regi?o se caracteriza pela forte presen?a de processos f?sicos costeiros, com batimetria rasa e complexas fei??es de fundo. A presen?a intensa de atividades petrol?feras faz da regi?o uma das mais importantes para o desenvolvimento socioecon?mico do estado, mas, por outro lado, potencializa a possibilidade de acidentes ambientais de grandes e graves propor??es. O modelo de circula??o hidrodin?mica utilizado foi o 2DH, que faz parte do Sistema de Hidrodin?mica Ambiental, chamado SisBaHiA?, desenvolvido pela ?rea de Engenharia Costeira e Oceanogr?fica do Programa de Engenharia Oce?nica da COPPE/UFRJ. Os interpoladores avaliados foram Vizinho Natural, Krigagem, Triangula??o Irregular Linear, Inverso da Dist?ncia, Vizinho mais Pr?ximo, M?nima Curvatura, Fun??o de Base Radial, Polin?mio Local, Regress?o Polinomial, M?dia M?vel, M?trica de Dados e M?todo de Shepard Modificado, implementados no software comercial Surfer? para a gera??o dos MDTs. Os dados batim?tricos, que serviram como base para a constru??o dos MDTs, s?o oriundos de campanha de campo e de cartas n?uticas. Os resultados das modelagens foram analisados pelas avalia??es dos campos de velocidade e eleva??o, sob tr?s aspectos: uma vis?o espacial dos resultados, atrav?s da an?lise de tr?s perfis perpendiculares ? linha de costa e um perfil transversal ? linha de costa; uma vis?o temporal dos resultados, ao longo do per?odo de 30 dias, a partir de tr?s n?s centrais da malha; e finalmente uma an?lise hodogr?fica das componentes de velocidade em U e V, em diferentes ciclos de mar?s. Foram verificadas varia??es pouco significativas nos campos de eleva??es, podendo as mesmas serem desprezadas, por?m no que diz respeito aos campos de velocidade e dire??es de fluxo, notam-se varia??es associadas aos MDTs utilizados, uma vez que todas as condicionantes hidrodin?micas foram mantidas

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Koch, Alexander. "Auswirkungen der koronaren Kollateralisierung bei Patienten mit akutem ST-Elevations-Myokardinfarkt und primärer perkutaner Koronarintervention." Doctoral thesis, Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-146666.

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Ziel der Studie war es zu analysieren, welchen Einfluss eine angiographisch sichtbare Kollateralisierung vor Revaskularisation bei Patienten mit einem akuten ST-Elevations-Myokardinfarkt (STEMI) und primärer perkutaner Koronarintervention (PCI) auf verschiedene in der kardialen Magnetresonanztomographie messbare Parameter und auf die klinische Prognose hat. Es wurden 235 Patienten mit STEMI und einem Symptombeginn <12 Stunden in die Analyse eingeschlossen. Alle Patienten wiesen einen funktionell insuffizienten antegraden Fluss in der Infarktarterie auf. Die Patienten wurden in zwei Gruppen unterteilt: Gruppe A mit fehlender oder nur geringer Kollateralversorgung (n=166) und Gruppe B mit einer signifikanten Kollateralisierung (n=69). Es wurden Infarktgröße, mikrovaskuläre Obstruktion und linksventrikuläre Funktion mittels Magnetresonanztomographie im Median 3 Tage nach dem Infarktereignis bestimmt sowie die Patienten über einen Zeitraum von >2 Jahren nachbeobachtet. Das Ausmaß der frühen mikrovaskulären Obstruktion war in Gruppe B signifikant geringer (3,3% gegenüber 2,1% der linksventrikuläre Masse, p = 0,009). Die mittels maximaler Kreatinkinase-MB-Ausschüttung gemessene Infarktgröße war in Gruppe B kleiner (p=0,02). Bei 227 Patienten (97%) wurde nach im Median 2,2 Jahren eine klinische Verlaufskontrolle durchgeführt. Insgesamt starben während des Kontrollzeitraums 25 Patienten: 22 Patienten (13,8%) der Gruppe A mit fehlender oder nur schwacher Kollateralisierung und 3 Patienten (4,4%) der Gruppe B mit signifikanter Kollateralversorgung vor Behandlungsbeginn (p=0,04). In Gruppe A traten 12 (7,5%) nicht-tödliche Reinfarkte auf im Vergleich zu 2 (2,9%) in Gruppe B (p=0,18). Ein kombinierter Endpunkt aus Tod oder nicht-tödlichem Reinfarkt trat in Gruppe B signifikant seltener auf als in Gruppe A (p=0,02). Zusammenfassend lässt sich formulieren, dass gut ausgebildete Kollateralgefäße vor einer Revaskularisation mittels PCI bei Patienten mit akuten STEMI mit einer schützenden Wirkung auf die koronare Mikrozirkulation und einem besseren Langzeit-Überleben assoziiert sind.

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McMillan, Samuel. "Voortdurende verbetering : 'n noodsaaklikheid vir volgehoue groei van 'n gemeenskapskoerant met spesifieke verwysing na die publikasie - Paarl Post." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/52053.

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Thesis (MBA)--Stellenbosch University, 2000.
ENGLISH ABSTRACT: The economic viability and continuity of any publication is determined by two critical factors, being: • The circulation of the publication, thus the readership, as well as • the advertising volumes of the publication. This particular study started by the realisation by management of the publication, Paarl Post, that these two critical factors had in real terms actually been declining since 1996, albeit marginally. The theme of continuous improvement was identified as critical in the process of eliminating "highs and lows", thus certain key areas had to be addressed. Furthermore these areas had to be continously evaluated and monitored. The process of change started with a process of gathering of information by means of questionnaires and personal interviews with certain key personnel by external consultants. A two-day session was scheduled where this information was processed with the help of the consultants and key personnel and the conclusion was made that the growth in circulation and advertising volumes and ultimately the growth in the publication was a function of certain key areas to be managed in the following way: • Cost efficient • Initiatives that lead to product growth • Optimizing of service • Continuous improvement of processes • Optimal use of manpower. The key areas of Marketing, Product, Communication, Processes and Information Technology were identified as key projects, which led to certain recommendations by these project teams based on abovementioned criteria. The "final" phase in the formal process, essentially a phase which never ends, is the implementation of the recommendations, and the continuous monitoring and following-up of the initiatives which ultimately develop to a continuous process of improvement, with the result: • Continuous circulation growth and • continous growth in advertising volumes, and ultimately continuous real growth in the community publication, Paarl Post.
AFRIKAANSE OPSOMMING: Enige publikasie se ekonomiese lewensvatbaarheid en kontinuïteit word deur twee kritieke faktore bepaal, naamlik: • Sirkulasie, m.a.w. die lesergetalle van die publikasie en • advertensievolumes Hierdie studie is gebore in die bestuur van die publikasie se waarneming dat hierdie twee aspekte van die gemeenskapskoerant, Paarl Post, sedert 1996 afneem in reële terme en dus die ekonomiese kontinuïteit van die publikasie bedreig. Die tema van voordurende verbetering is geïdentifiseer as krities in die totale proses ten einde "highs and lows" uit te skakel. Dus moes sekere sleutel-areas aangespreek word, maar hierdie areas moes verder ook deurlopend geëvalueer en gemonitor word. Die proses van verandering is begin deur 'n proses waarby eksterne konsultante betrek is om die eerste fase van die proses te fasiliteer in terme van die inwin van inligting deur middel van vraelyste en persoonlike onderhoude met sleutelpersoneel soos deur bestuur geïdentifiseer. 'n Tweedag sessie is geskeduleer waarby hierdie inligting met die hulp van die konsultante en die sleutelpersoneel deurgewerk is en die slotsom bereik is, dat groei in sirkulasie en advertensievolumes en dus uiteindelik die groei van die publikasie 'n funksie is van die mate waartoe sleutelareas van die Paarl Post as volg bestuur word: • Koste--effektief • Inisiatiewe wat tot produk-groei lei • Dienslewering optimaliseer • Voortdurende verbetering van prosesse • Optimale benutting van mannekrag. Die sleutelareas van Bemarking, Produk, Kommunikasie, Prosesse en Inligtingstegnologie is as projekte geïdentifiseer, waarvan die uiteinde is dat elke projekspan sekere aanbevelings moes doen aan die hand van bogenoemde kriteria. Die "laaste" stap in die formele proses, wat uiteindelik 'n stap is wat nooit eindig nie, is die implementering van die aanbevelings, asook die voordurende monitering en opvolging van die inisiatiewe wat uiteindelik ontwikkel in 'n deurlopende proses van verbetering, met die resultaat: • Volgehoue sirkulasiegroei, asook • volgehoue groei in advertensievolumes en uiteindelik voordurende reële groei van die gemeenskapspublikasie, Paarl Post.

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Reichert, Bernhard K. "Quantification of natural climate variability in paleoclimatic proxy data using general circulation models : application to glacier systems = Quantifizierung der natürlichen Klimavariabilität in Paläoklimatischen Proxy-Daten mit Hilfe von Modellen der Allgemeinen Zirkulation : Anwendung auf Gletschersysteme /." [S.l. : s.n.], 2000. http://www.sub.uni-hamburg.de/disse/197/THESIS.PDF.

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Baquero, Bernal Astrid. "Interannual climate variability in the tropical Indian Ocean : a study with a hierarchy of coupled general circulation models = Interannuale Klimavariabilität im tropischen Indischen Ozean : eine Untersuchung mit einer Hierarchie von globalen gekoppelten Ozean-Atmosphären-Modellen /." Hamburg : Max-Planck-Institut für Meteorologie, 2004. http://mpimet.mpg.de/de/web/download.php?src=max_erdsystem&file=pdfupload&id=15&filename=BzE_8.pdf.

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Lankhorst, Matthias [Verfasser]. "Analyses of the circulation in intermediate and shallow water masses of the North Atlantic with Lagrangian and profiling methods = Untersuchungen zur Zirkulation in mittleren und oberen Wassermassen des Nordatlantiks mit Lagrange'schen und profilierenden Methoden / Matthias Lankhorst." Kiel : Universitätsbibliothek Kiel, 2008. http://d-nb.info/1019543906/34.

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Kan, Casina. "The role of Dysregulated Microrna in Ovarian Cancer." Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/10108.

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Ovarian cancer is the most lethal gynaecological malignancy and the sixth most common cause of cancer death in Australian women. Epithelial ovarian cancer accounts for 90% of ovarian cancers, of which, serous epithelial ovarian cancer is the most common and aggressive histological subtype. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that negatively regulate genes involved in cancer. Genomic instability is a hallmark of ovarian cancer which may be exacerbated by DNA hypomethylation. The role of aberrant methylation and copy number variation (CNV) on miRNA dysregulation was assessed by qPCR methylation arrays and integrative analysis of cytogenetic arrays, miRNA expression and gene expression profiles. Several miRNAs identified to be adjacent to CpG islands aberrantly methylated or located in regions of CNV. Of these, the mir-23a/mir-24-2/mir-27a cluster and mir-425 were identified to be in regions of CNV and were predicted to target oncogenic receptor tyrosine kinases AXL and MET. Furthermore, one of the unmet needs for ovarian cancer patient survival is reliable detection. Current diagnostic tests for ovarian cancer may be improved by expansion of biomarker panels such as circulating miRNAs. Assessment of miRNA expression profiles identified the miR-200 family to be over-expressed in ovarian cancer patient serum.

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Castruccio, Frédéric. "Apports des données gravimétriques GRACE pour l'assimilation de données altimétriques et in-situ dans un modèle de l'Océan Pacifique Tropical." Phd thesis, Université Joseph Fourier (Grenoble), 2006. http://tel.archives-ouvertes.fr/tel-00138506.

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L'objectif de ce travail est d'estimer les apports d'une topographie dynamique moyenne (MDT) déduite des données gravimétriques GRACE, pour la reconstruction de la circulation océanique du Pacifique Tropical par assimilation de données.
Les récentes avancées de notre connaissance du géoïde nous ont conduit à étudier l'impact de l'utilisation d'un signal altimétrique absolu. Un modèle (OPA) de l'Océan Pacifique Tropical, où des observations in-situ et quasi-synoptiques sont disponibles (réseau TAO), et un filtre de Kalman en rang réduit (SEEK) ont été mis au point et utilisés dans différentes configurations. La première suppose une situation pré-GRACE et utilise une MDT artificielle. La deuxième utilise une MDT observée déduite du géoïde GRACE. Conjointement à l'altimétrie, les profils de température TAO sont assimilés.
Ce travail montre l'importance d'une bonne référence pour les résidus altimétriques. Le résultat le plus important concerne la capacité du système d'assimilation utilisant GRACE à mieux composer avec des données mixtes: satellites et in-situ. Ici, l'assimilation conjointe d'altimétrie et de données TAO est plus performante grâce à la meilleure compatibilité des données.
En outre, une analyse physique, qui considère l'apport de l'assimilation à l'amélioration de la représentation de la dynamique du Pacifique Tropical, a été conduite. L'originalité de ce travail est de montrer comment l'assimilation contribue à améliorer notre compréhension des mécanismes physiques en action dans ce bassin.
De manière intéressante et rétrospective, cette analyse révèle aussi une zone (8°N) où les données GRACE semblent avoir des faiblesses qu'il serait judicieux de corriger.

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Bou, Farah Mira. "Méthodes utilisant des fonctions de croyance pour la gestion des informations imparfaites dans les réseaux de véhicules." Thesis, Artois, 2014. http://www.theses.fr/2014ARTO0208/document.

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La popularisation des véhicules a engendré des problèmes de sécurité et d’environnement. Desprojets ont été lancés à travers le monde pour améliorer la sécurité sur la route, réduire l’encombrementdu trafic et apporter plus de confort aux conducteurs. L’environnement des réseaux devéhicules est complexe et dynamique, les sources sont souvent hétérogènes, de ce fait les informationséchangées peuvent souvent être imparfaites. La théorie des fonctions de croyance modélisesouplement les connaissances et fournit des outils riches pour gérer les différents types d’imperfection.Elle est utilisée pour représenter l’incertitude, gérer les différentes informations acquises etles fusionner. Nous nous intéressons à la gestion des informations imparfaites échangées entre lesvéhicules concernant les événements sur la route. Les événements locaux et les événements étendusn’ayant pas les mêmes caractéristiques, les travaux réalisés les distinguent. Dans un environnementsans infrastructure où chaque véhicule a son propre module de fusion, l’objectif est de fournir auxconducteurs la synthèse la plus proche possible de la réalité. Différents modèles fondés sur desfonctions de croyance sont proposés et différentes stratégies sont étudiées : affaiblir ou renforcervers l’absence de l’événement pour prendre en compte le vieillissement des messages, garder lesmessages initiaux ou seulement le résultat de la fusion dans la base des véhicules, considérer la miseà jour du monde, prendre en compte l’influence du voisinage pour gérer la spatialité des embouteillages.Les perspectives restent nombreuses, certaines sont développées dans ce manuscrit commela généralisation des méthodes proposées à tous les événements étendus tels que les brouillards
The popularization of vehicles has created safety and environmental problems. Projects havebeen launched worldwide to improve road safety, reduce traffic congestion and bring more comfortto drivers. The vehicle network environment is dynamic and complex, sources are often heterogeneous,and therefore the exchanged information may be imperfect. The theory of belief functionsoffers flexibility in uncertainty modeling and provides rich tools for managing different types of imperfection.It is used to represent uncertainty, manage and fuse the various acquired information.We focus on the management of imperfect information exchanged between vehicles concerningevents on the road. The carried work distinguishes local events and spatial events, which do nothave the same characteristics. In an environment without infrastructure where each vehicle is afusion center and creates its own vision, the goal is to provide to each driver the synthesis of thesituation on the road as close as possible to the reality. Different models using belief functionsare proposed. Different strategies are considered: discount or reinforce towards the absence of theevent to take into account messages ageing, keep the original messages or just the fusion result invehicle database, consider the world update, manage the spatiality of traffic jam events by takinginto account neighborhood. Perspectives remain numerous; some are developed in the manuscriptas the generalization of proposed methods to all spatial events such as fog blankets

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Moorman, Ruth. "Response of Antarctic ocean circulation to increased meltwater." Thesis, 2019. http://hdl.handle.net/1885/187134.

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The implications of ocean freshening from accelerating Antarctic land-ice loss are poorly understood, due to the scarcity of observations near the Antarctic coast, and the high spatial and temporal resolution required to resolve Antarctic continental shelf processes in ocean models. Here, a high-resolution global ocean--sea-ice model is used to investigate the response of Antarctic continental shelf circulation to increasing meltwater. Two freshwater perturbation experiments are conducted, using projected Antarctic ice-loss rates under RCP 4.5 and RCP 8.5 emissions scenarios at 2100.We find that surface freshening near the Antarctic coast increases stratification and reduces the formation of cold, dense waters on the Antarctic continental shelf that, in the current climate, drive abyssal ocean circulation and ventilation. In our simulations, the connection between the abyssal ocean and the cold Antarctic shelf collapses within 10 years following the application of projected 2100 meltwater forcing, as downwelling surface waters on the continental shelf are freshened by glacial runoff, leaving them too buoyant to sink to the abyssal ocean. Around Antarctica, coastal freshening increases lateral density gradients between the cool, fresh shelf and the warm, saline open ocean, strengthening frontal structures that separate the adjacent water-masses, and accelerating geostrophic currents that flow westward along the coast and along the continental shelf break. This process acts to homogenise shelf waters and increasingly isolate the cool continental shelf from the warmer open ocean, leading to a net cooling on the continental shelf. Acceleration of the circumpolar coastal current results in remote temperature feedbacks unique to these experiments; most notable being a strong cooling signal on the West Antarctic shelf, an historically warm region associated with high rates of ice shelf melt, generated by the advection of cold Weddell Sea shelf waters around the Antarctic Peninsula by the strengthening coastal current. However, shelf cooling is not a circumpolar response to freshening. Deep warm anomalies arise in the Ross Sea, Adelie Coast, and Prydz Bay continental shelf dense water source regions under enhanced meltwater forcing, as full depth convention collapses and surface cooling fluxes diminish. Warming is strongest in the Ross Sea, where the absence of strong frontal structures and zonal currents at the shelf break grants warm, open ocean waters uninhibited access to the shelf. On the Prydz Bay and Adelie Coast shelf, warming due to convective shutdown is counterbalanced by decreased shoreward advective heat transport, due to strengthening frontal structures at the shelf break. As such, we find that coastal freshening induces both warm and cool anomalies at different locations along the Antarctic continental shelf, suggesting that shelf freshening by meltwater can both accelerate ice shelf melt (a positive feedback) and inhibit melt (a negative feedback) depending on regional factors. These findings improve our understanding of the complex suite of climate effects associated with the melting of Antarctica's land-ice. Both the disruption of abyssal overturning and shifts in heat transport to ice shelves have implications for sea-level rise; as reduced deep ocean ventilation may increase oceanic heat content (effecting steric sea-level), and accelerating land-ice loss, in regions of warming, adds mass to the oceans (effecting eustatic sea-level).

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Vellinga, Michael. "Bifurcations and dynamics of the ocean's thermohaline circulation Vertakkingen en dynamica van de thermohaline oceaancirculatie : met een samenvatting in het Nederlands /." 1997. http://catalog.hathitrust.org/api/volumes/oclc/36712025.html.

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Koch, Alexander. "Auswirkungen der koronaren Kollateralisierung bei Patienten mit akutem ST-Elevations-Myokardinfarkt und primärer perkutaner Koronarintervention." Doctoral thesis, 2013. https://ul.qucosa.de/id/qucosa%3A12657.

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Ziel der Studie war es zu analysieren, welchen Einfluss eine angiographisch sichtbare Kollateralisierung vor Revaskularisation bei Patienten mit einem akuten ST-Elevations-Myokardinfarkt (STEMI) und primärer perkutaner Koronarintervention (PCI) auf verschiedene in der kardialen Magnetresonanztomographie messbare Parameter und auf die klinische Prognose hat. Es wurden 235 Patienten mit STEMI und einem Symptombeginn <12 Stunden in die Analyse eingeschlossen. Alle Patienten wiesen einen funktionell insuffizienten antegraden Fluss in der Infarktarterie auf. Die Patienten wurden in zwei Gruppen unterteilt: Gruppe A mit fehlender oder nur geringer Kollateralversorgung (n=166) und Gruppe B mit einer signifikanten Kollateralisierung (n=69). Es wurden Infarktgröße, mikrovaskuläre Obstruktion und linksventrikuläre Funktion mittels Magnetresonanztomographie im Median 3 Tage nach dem Infarktereignis bestimmt sowie die Patienten über einen Zeitraum von >2 Jahren nachbeobachtet. Das Ausmaß der frühen mikrovaskulären Obstruktion war in Gruppe B signifikant geringer (3,3% gegenüber 2,1% der linksventrikuläre Masse, p = 0,009). Die mittels maximaler Kreatinkinase-MB-Ausschüttung gemessene Infarktgröße war in Gruppe B kleiner (p=0,02). Bei 227 Patienten (97%) wurde nach im Median 2,2 Jahren eine klinische Verlaufskontrolle durchgeführt. Insgesamt starben während des Kontrollzeitraums 25 Patienten: 22 Patienten (13,8%) der Gruppe A mit fehlender oder nur schwacher Kollateralisierung und 3 Patienten (4,4%) der Gruppe B mit signifikanter Kollateralversorgung vor Behandlungsbeginn (p=0,04). In Gruppe A traten 12 (7,5%) nicht-tödliche Reinfarkte auf im Vergleich zu 2 (2,9%) in Gruppe B (p=0,18). Ein kombinierter Endpunkt aus Tod oder nicht-tödlichem Reinfarkt trat in Gruppe B signifikant seltener auf als in Gruppe A (p=0,02). Zusammenfassend lässt sich formulieren, dass gut ausgebildete Kollateralgefäße vor einer Revaskularisation mittels PCI bei Patienten mit akuten STEMI mit einer schützenden Wirkung auf die koronare Mikrozirkulation und einem besseren Langzeit-Überleben assoziiert sind.:1 BIBLIOGRAPHISCHE BESCHREIBUNG 2 ABKÜRZUNGSVERZEICHNIS 3 EINFÜHRUNG 4 AUFGABENSTELLUNG 5 MATERIALIEN UND METHODEN 5.1 Überblick über das Studiendesign 5.2 Koronarintervention 5.3 Enzymatische Infarktgröße 5.4 Kardiale Magnetresonanztomographie 5.4.1 Linksventrikuläre Volumina und Ejektionsfraktion 5.4.2 Infarktgröße 5.4.3 Mikrovaskuläre Obstruktion 5.5 Klinisches Follow-up 5.6 Statistik 6 ERGEBNISSE 6.1 Patientencharakteristika 6.2 Enzymatische Infarktgröße 6.3 Magnetresonanztomographie 6.4 Klinische Ereignisse im Langzeitverlauf 6.5 Prädiktoren klinischer Ereignisse 6.5.1 Univariate Cox-Regressions-Analyse 6.5.2 Multivariate Cox-Regressions-Analyse 6.6 Klinische Ergebnisse in Abhängigkeit von der Zeit zwischen Symptombeginn und Reperfusion 6.7 Magnetresonanztomographische Ergebnisse in Abhängigkeit von der Zeit zwischen Symptombeginn und Reperfusion 7 DISKUSSION 7.1 Limitationen 8 ZUSAMMENFASSUNG DER ARBEIT 9 LITERATURVERZEICHNIS 10 DANKSAGUNG 11 ERKLÄRUNG ÜBER DIE EIGENSTÄNDIGE ABFASSUNG DER ARBEIT 12 LEBENSLAUF 13 PUBLIKATIONEN

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Hillmann, Nadine. "Methodenvergleich zur Erfassung einer Restheparinisierung nach kardiochirurgischen Eingriffen mit Herz-Lungen-Maschine." Doctoral thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-002B-7CD3-9.

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Dissertations / Theses on the topic 'MLT circulation'

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