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A genetic dissection of actin regulation in Drosophila hemocytesTucker, Philippa January 2011 (has links)
Cell migration is essential for embryonic development, it occurs in adult organisms during processes like wound healing and its misregulation contributes to pathological conditions such as metastasis. Despite this, most studies of cell migration have been undertaken in vitro. Ena/VASP proteins, believed to be actin anti-capping proteins, have been studied extensively in fibroblasts in vitro, and using Drosophila macrophages (hemocytes) within the developing embryo, the role of the Drosophila homologue of Mena, Ena, is investigated in vivo. Consistent with data from fibroblasts in vitro, Ena localised to regions of actin dynamics within migratory hemocytes, where this protein stimulated lamellipodial dynamics and positively regulated filopodial number and length. However, whilst overexpression of Ena/VASP proteins in fibroblasts reduced migration speeds, Ena overexpression in hemocytes dramatically increased migration speeds in three different assays. This positive regulation of migration speed closely resembled the increased motility of breast cancer cells that overexpress Mena and evidence presented here, suggests that this key difference may be explained by spatial constraints that are imposed upon cells within three dimensional environments. Indeed, such constraints prevented ruffling, a more detrimental form of retraction, in hemocytes in vivo. Furthermore, fibroblasts overexpressing Mena in vitro form membrane ruffles more frequently. Therefore Ena/VASP proteins drive migration by enhancing lamellipodial protrusion, but in certain environments these protrusions are lost as ruffles slowing migration. The method by which Ena regulates lamellipodial protrusion and migration speeds was then investigated: Ena increased Fascin-mediated actin bundling and the number of Fascin rich-actin bundles that coalesced. Analysis of individual actin bundles revealed that coalescence increased protrusion rate and that both protrusion rate and coalescence, increased cell migration speeds. This suggests that Ena facilitates an increase in cell migration by promoting the coalescence of Fascin bundles, and positions Ena as a key regulator of migration speeds in vivo.
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Storleksoptimering av en etanolfabrik för integrering med ENA Energis kraftvärmeverk. : Baserat på en regional energibalans mellan tillgång på etanolbränsle i Enköping kommun och producerad etanol med hjälp av tillgänglig ånga från ENA kraftvärmeverk.Boström, Cecilia January 2008 (has links)
<h1>Abstract</h1><p>The future of ethanol is depending on good solutions for the production. ENA energy power plant produces electrical power and district heating by heating biofuel. By building an integrated bioenergy plant surplus steam could be used to produce ethanol as fuel to vehicle.</p><p>This would mean that ethanol is produced renewable energy and the energy for the process derives from the surplus of power. ENA energy, MDH (the University of Mälardalen) and the energy authority has initiated a research project were different bioenergy combinations integrate with existing power plant. As a part of the project which size an integrated factory should be to gain the best efficiency for the plant was investigated. Consideration will be taken to the cost of the production in order to be competitive to the price of imported ethanol.</p><p> </p><p> </p><p>Etanolens framtid vilar på bra lösningar för framställning. I ENA energi kraftverk i Enköping produceras el och fjärrvärme genom eldning av biobränsle. Genom att bygga ett integrerat bioenergikraftverk där skulle man kunna använda överskottsånga till att framställa etanol som fordonsbränsle. Detta skulle innebära att etanolen framställs med ett förnybart bränsle och energin till framställningen kommer från ett överskott på värme. ENA energi, MDH och energimyndigheten har initierat ett forskningsprojekt där en bioenergiintegrering skall undersökas. Som del i detta skall här undersökas vilken storlek en integrerad etanolfabrik skall ha för att nå högsta totala verkningsgrad för verket samt om framställningspriset kan konkurrera med importerad etanol.</p><p> </p>
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Storleksoptimering av en etanolfabrik för integrering med ENA Energis kraftvärmeverk. : Baserat på en regional energibalans mellan tillgång på etanolbränsle i Enköping kommun och producerad etanol med hjälp av tillgänglig ånga från ENA kraftvärmeverk.Boström, Cecilia January 2008 (has links)
Abstract The future of ethanol is depending on good solutions for the production. ENA energy power plant produces electrical power and district heating by heating biofuel. By building an integrated bioenergy plant surplus steam could be used to produce ethanol as fuel to vehicle. This would mean that ethanol is produced renewable energy and the energy for the process derives from the surplus of power. ENA energy, MDH (the University of Mälardalen) and the energy authority has initiated a research project were different bioenergy combinations integrate with existing power plant. As a part of the project which size an integrated factory should be to gain the best efficiency for the plant was investigated. Consideration will be taken to the cost of the production in order to be competitive to the price of imported ethanol. Etanolens framtid vilar på bra lösningar för framställning. I ENA energi kraftverk i Enköping produceras el och fjärrvärme genom eldning av biobränsle. Genom att bygga ett integrerat bioenergikraftverk där skulle man kunna använda överskottsånga till att framställa etanol som fordonsbränsle. Detta skulle innebära att etanolen framställs med ett förnybart bränsle och energin till framställningen kommer från ett överskott på värme. ENA energi, MDH och energimyndigheten har initierat ett forskningsprojekt där en bioenergiintegrering skall undersökas. Som del i detta skall här undersökas vilken storlek en integrerad etanolfabrik skall ha för att nå högsta totala verkningsgrad för verket samt om framställningspriset kan konkurrera med importerad etanol.
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Les stratégies de résistance féministe, lost in translation : comment la prose d'Ena Lucía Portela met les éthiques de la traduction à l'épreuveDes Rochers, Arianne January 2015 (has links)
La traduction peut-elle véritablement créer un dialogue transculturel éthique et non hiérarchique? C'est la question que souhaite déconstruire cette thèse, plutôt que d'y répondre. Celle-ci s'articule ainsi autour de la notion d'éthique de la traduction : en explorant d'abord certains des récents développements en théorie féministe et en traductologie, nous souhaitons découvrir les fondements de différentes éthiques du traduire afin de les mettre à l'épreuve. Puis, en analysant le style de l'auteure cubaine dissidente et transgressive Ena Lucía Portela en traductions française et anglaise, nous découvrons que la traduction fait subir de nombreux changements au discours transgressif de l'auteure, inscrivant celui-ci dans les normes des cultures d'arrivée. Nous en concluons que la pratique de la traduction doit revoir ses objectifs et ses stratégies et prendre en considération les arguments des théories féministes actuelles si elle veut pouvoir prétendre participer à un dialogue éthique et avoir une « visée résistante ». La présente thèse propose ainsi une réflexion féministe transnationale sur l'éthique et sur la pratique de la traduction littéraire à l'heure actuelle.
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Investigation of Diamond-like Carbon Charge State Conversion Surfaces for Low Energy Neutral Atom Imaging Detectors in Space ApplicationsNeuland, Maike Brigitte January 2012 (has links)
Interplanetary satellite missions and also satellites orbiting the Earth carry instruments to measure fluxes of neutral atoms, which are plasma key parameters for the investigation of the planets' atmospheres. Neutral atoms entering the mass-spectrometry instrument have to be ionized to be able to guide them using electric and magnetic fields with intent to determine energy and velocity of the atoms and finally their mass. For low energy neutral atoms, the ionization process can be realized by implementing a charge state conversion surface, where-on the atoms are scattered in an angle of grazing incidence and getting ionized.The objective of this work is the characterization and analysis of two diamond-like carbon surface samples by measuring and determining ionization efficiencies and scattering properties and therefore their functionality as charge state conversion surfaces.First, a chemical vapor deposition (CVD) diamond sample is investigated. Furthermore the CVD diamond is compared to another diamond--like carbon surface manufactured by pulsed laser deposition (PLD) technique. All measurements have been accomplished at the ILENA (Imager for Low Energy Neutral Atoms) facility at the Physics Institute, University of Bern in the Department of Space Research and Planetary Sciences.It is discovered that the CVD surface gets electrostatically charged upon scattering of atomic ions. Though this charging effects, a qualitative characterization of the surface can be made. It is shown that the ionization efficiencies of the CVD and the PLD diamond surface are of comparable quality, where on the contrary the scattering properties of the CVD diamond charge state conversion surface are much better. It still has to be investigated in future experiments, if this brilliant scattering properties are due to charging effects or can be assigned to the very smooth surface of the CVD diamond surface. / <p>Validerat; 20120112 (anonymous)</p>
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Modulace chemokinového profilu lidských makrofágů a renálního epitelu / Modulation of human macrophages and renal epitelium chemokine profilePidhorodetská, Halyna January 2018 (has links)
One of the main effects of pro-inflammatory cytokines is the induction of chemokines and the expression of adhesive molecules that regulate the migration of immune cells to the center of the damage. Chemoattractant gradient also provides a physiological delivery of cells to tissues and lymphatic organs under normal circumstances. Chemokines are chemotactic cytokines that form a very large and diverse group of secreted proteins that have many functions both in processes that maintain homeostasis but also in inflammatory states. Production of some chemokines also has a major effect on graft rejection. Further understanding of the mechanisms involved in the acute rejection chemokine could contribute to improving treatment steps in transplantology. In this diploma thesis, serum chemokine levels were monitored in renal transplant patients, but these measurements did not show significant dynamics. Furthermore, the effect of pro-inflammatory cytokines on the release of chemokines from renal epithelial cells and monocytes was studied. Experiments were performed to monitor the levels of individual chemokines such as ENA-78, IL-8, MCP-1, MIP-1 β, RANTES, GRO alpha, THP-1 (monocyte/macrophage cell line), RPTEC (renal epithelial cells of proximal tubules) and RA (renal cell tumor lines). TNF-α (tumor necrosis...
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Chemokiny u transplantace ledviny a jejich tvorba lidskými makrofágy a renálním epitelem / Chemokines in kidney transplantation and their production by human macrophages and renal epithelial cells.Pidhorodetská, Halyna January 2018 (has links)
One of the main effects of pro-inflammatory cytokines is the induction of chemokines and the expression of adhesive molecules that regulate the migration of immune cells to the center of the damage. Chemoattractant gradient also provides a physiological delivery of cells to tissues and lymphatic organs under normal circumstances. Chemokines are chemotactic cytokines that form a very large and diverse group of secreted proteins that have many functions both in processes that maintain homeostasis but also in inflammatory states. Production of some chemokines also has a major effect on graft rejection. Further understanding of the mechanisms involved in the acute rejection chemokine could contribute to improving treatment steps in transplantology. In this diploma thesis, serum chemokine levels were monitored in renal transplant patients, but these measurements did not show significant dynamics. Furthermore, the effect of pro- inflammatory cytokines on the release of chemokines from renal epithelial cells and monocytes was studied. Experiments were performed to monitor the levels of individual chemokines such as ENA-78, IL-8, MCP-1, MIP-1β, RANTES, GRO-α, THP-1 (monocyte/macrophage cell line), RPTEC (renal epithelial cells of proximal tubules) and RA (renal cell tumor lines). TNF-α had an effect on the...
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The Neutral Particle Detector on the Mars and Venus Express missionsGrigoriev, Alexander January 2007 (has links)
<p>The Neutral Particle Detector (NPD) is a new type of instrumentation for energetic neutral atom (ENA) diagnostics. This thesis deals with development of the NPD sensor designed as a part of the plasma and neutral particle packages ASPERA-3 and ASPERA-4 on board Mars Express and Venus Express, the European Space Agency (ESA) satellites to Mars and Venus, respectively. It describes how the NPD sensors were designed, developed, tested and calibrated. </p><p>It also presents the first scientific results obtained with NPD during its operation at Mars. </p><p>The NPD package consists of two identical detectors, NPD1 and NPD2. Each detector has a 9<sup>o</sup> x 90<sup>o</sup> intrinsic field-of-view divided into three sectors. The ENA detection principle is based on the surface interaction technique. NPD detects ENA differential fluxes within the energy range of 100 eV to 10 keV and is capable of resolving hydrogen and oxygen atoms by time-of-flight (TOF) measurements or pulse height analysis.</p><p>During the calibration process the detailed response of the sensor was defined, including properties such as an angular response function and energy dependent efficiency of each of the sensor sectors for different ENA species. </p><p>Based on the NPD measurements at Mars the main scientific results reported so far are:</p><p>- observation of the Martian H-ENA jet / cone and its dynamics, </p><p>- observations of ENA emissions from the Martian upper atmosphere, </p><p>- measurements of the hydrogen exosphere density profile at Mars, </p><p>- observations of the response of the Martian plasma environment to an interplanetary shock, </p><p>- observations of the H-ENA fluxes in the interplanetary medium.</p>
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The Neutral Particle Detector on the Mars and Venus Express missionsGrigoriev, Alexander January 2007 (has links)
The Neutral Particle Detector (NPD) is a new type of instrumentation for energetic neutral atom (ENA) diagnostics. This thesis deals with development of the NPD sensor designed as a part of the plasma and neutral particle packages ASPERA-3 and ASPERA-4 on board Mars Express and Venus Express, the European Space Agency (ESA) satellites to Mars and Venus, respectively. It describes how the NPD sensors were designed, developed, tested and calibrated. It also presents the first scientific results obtained with NPD during its operation at Mars. The NPD package consists of two identical detectors, NPD1 and NPD2. Each detector has a 9o x 90o intrinsic field-of-view divided into three sectors. The ENA detection principle is based on the surface interaction technique. NPD detects ENA differential fluxes within the energy range of 100 eV to 10 keV and is capable of resolving hydrogen and oxygen atoms by time-of-flight (TOF) measurements or pulse height analysis. During the calibration process the detailed response of the sensor was defined, including properties such as an angular response function and energy dependent efficiency of each of the sensor sectors for different ENA species. Based on the NPD measurements at Mars the main scientific results reported so far are: - observation of the Martian H-ENA jet / cone and its dynamics, - observations of ENA emissions from the Martian upper atmosphere, - measurements of the hydrogen exosphere density profile at Mars, - observations of the response of the Martian plasma environment to an interplanetary shock, - observations of the H-ENA fluxes in the interplanetary medium.
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Identification of Genes Involved in the C. elegans VAB-1 Eph Receptor Tyrosine Kinase Signaling PathwayMOHAMED, AHMED 29 July 2011 (has links)
The generation of a functional nervous system requires that neuronal cells and axons navigate precisely to their appropriate targets. The Eph Receptor Tyrosine Kinases (RTKs) and their ephrin ligands have emerged as one of the important guidance cues for neuronal and axon navigation. However, the molecular mechanisms of how Eph RTKs regulate these processes are still incomplete. The purpose of this work was to contribute to the understanding of how Eph receptors regulate axon guidance by identifying and characterizing components of the Caenorhabditis elegans Eph RTK (VAB-1) signaling pathway. To achieve this objective I utilized a hyper active form of the VAB-1 Eph RTK (MYR-VAB-1) that caused penetrant axon guidance defects in the PLM mechanosensory neurons, and screened for suppressors of the MYR-VAB-1 phenotype. Through a candidate gene approach, I identified the adaptor NCK-1 as a downstream effector of VAB-1. Molecular and genetic analysis revealed that the nck-1 gene encodes for two isoforms (NCK-1A and NCK-1B) that share similar expression patterns in parts of the nervous system, but also have independent expression patterns in other tissues. Genetic rescue experiments showed that both NCK-1 isoforms can function in axon guidance, but each isoform also has specific functions. In vitro binding assays showed that NCK-1 binds to VAB-1 in a kinase dependent manner. In addition to NCK-1, WSP-1/N-WASP was also identified as an effector of VAB-1 signaling. Phenotypic analysis showed that nck-1 and wsp-1 mutants had PLM axon over extension defects similar to vab-1 animals. Furthermore, VAB-1, NCK-1 and WSP-1 formed a complex in vitro. Intriguingly, protein binding assays showed that NCK-1 can also bind to the actin regulator UNC-34/Ena, but genetic experiments suggest that unc-34 is an inhibitor of nck-1 function. Through various genetic and biochemical experiments, I provide evidence that VAB-1 can disrupt the NCK-1/UNC-34 complex, and negatively regulate UNC-34. Taken together, my work provides a model of how VAB-1 RTK signaling can inhibit axon extension. I propose that activated VAB-1 can prevent axon extension by inhibiting growth cone filopodia formation. This is accomplished by inhibiting UNC-34/Ena activity, and simultaneously activating Arp2/3 through a VAB-1/NCK-1/WSP-1 complex. / Thesis (Ph.D, Biology) -- Queen's University, 2011-07-28 16:20:31.957
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