• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 7
  • 1
  • Tagged with
  • 11
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Role of cholesterol and N-glycosylation in apical sorting of GPI- APs in polarized epithelial FRT cells / Rôle du cholestérol et de la N-glycosylation dans le tri apical de GPI-APs dans les cellules polarisées épithéliales FRT

Imjeti, Naga Sailaja 01 July 2011 (has links)
Les cellules épithéliales sont capable de se polariser avec un domaine apical et un basolatéral qui diffèrent nettement en leurs protéines, leurs composition en lipides et donc en fonction. Cette asymétrie reflète la capacité des cellules épithéliales à affecter les protéines nouvellement synthétisées et les lipides à chacune des surfaces de la cellule. Alors que les signaux responsables pour la sélection basolatérale des protéines ont été clairement identifiés, la situation en ce qui concerne la sélection apicale des protéines demeure mal comprise. Nous avons précédemment montré que contrairement aux GPI-APs basolatérales l’oligoisomérisation des protéines ancrées glycosylphosphatidylinositol (GPI-AP) dans l'appareil de Golgi est requise pour le tri apical. Il est intéressent de noter que ce mécanisme est conservé dans deux types de cellules épithéliales, les cellules MDCK et les cellules FRT, qui présentent des différences de tri des GPI-APs. Cependant, le mécanisme précis menant à cet événement n'est pas compris. Nos données précédentes ont démontré que le simple ajout de cholestérol aux cellules MDCK est nécessaire et suffisant pour induire l'oligomérisation et le tri apical d'une GPI-AP basolatérale. Alors que dans l’étude présente sur les cellules FRT, nous avons montré que contrairement aux cellules MDCK, le cholestérol ne joue pas un rôle majeur dans la régulation du tri apicale des GPI-APs. De plus, nous avons également montré que les GPI-APs apicales et basolatérales ne sont pas séparées dans le Golgi en fonction de leur teneur en cholestérol entourant l'environnement membranaire. Par ailleurs, nous avon démontré que la N-glycosylation des protéines de l’ectodomaine est indispensable à l’oligomérisation et au tri apical de GPI-APS. Nos données indiquent qu’il existe au moins deux mécanismes, l’un dépendant du taux de cholestérol et l’autre de la N-glycosylation, qui déterminent l’oligomérisation dans l'appareil de Golgi et le tri des GPI-APs vers la membrane apicale. / Epithelial cells represent the ability to polarize with an apical and basolateral domains which differ markedly in proteins, lipid composition and therefore in function. This asymmetry reflects the ability of epithelial cells to sort newly synthesized proteins and lipid to either cell surface. While the signals responsible for basolateral targeting of the proteins have been clearly understood, the situation regarding the apical sorting of proteins is more obscure. We have previously shown that differently from basolateral GPI-APs oligomerization in the Golgi apparatus is necessary for apical sorting of Glycosylphosphatidylinositol- anchored proteins (GPI-APs). Interestingly this mechanism is conserved in two different kinds of epithelial cells, MDCK and FRT cells, which exhibits a difference in the sorting of GPI-APs. However the precise mechanism leading to this event is not understood. Our previous data demonstrated that simple addition of cholesterol to MDCK cells is necessary and sufficient to induce the oligomerization and apical sorting of a basolateral GPI-AP. Whereas, in this present study in FRT cells we showed that in contrast with MDCK cells cholesterol is not an active player in the regulation of GPI- APs apical sorting. In addition, we also showed that apical and basolateral GPI-APs are not segregated in the Golgi on the bases of the cholesterol content of the surrounding membrane environment. Furthermore, we demonstrated that N- glycosylation of the protein ectodomain is critical for oligomerization and apical sorting of GPI-APs. Our data indicates that at least two mechanisms depending either on cholesterol or on N-glycosylation exist to determine oligomerization in the Golgi and sorting to the apical membrane of GPI-APs.
2

2021: A Face Odyssey : An analysis of the proposed AI Act and its effect on current law and the police’s ability to use facial recognition technology

Rehnlund Ingblad, Milton January 2023 (has links)
Artificial intelligence is becoming an increasingly important part of our lives and can be found in everything from fridges to phones. One of the applications of AI is the police use of facial recognition technology for law enforcement purposes. However, the use poses a major risk to fundamental rights. As part of the European Commission's initiative to create a Union fit for the digital age, the proposal for an AI Act was introduced in 2021 with the aim of setting the limit of permissible use of AI. In the act, the use of real-time facial recognition is prohibited except for a few exceptions which the police in the Union argue will severely hinder their work. However, the scope of the prohibition is ambiguous, and the act is riddled with various problems in its regulation of facial recognition used for law enforcement purposes. This thesis will therefore critically analyse the AI Act on the basis of three research questions. The first question examines how the AI Act will affect current law and the police’s ability to use facial recognition for law enforcement purposes. This thesis finds regarding real-time facial recognition, the act will replace LED as applicable law. However, for high-risk applications of FRT, there will be an interplay between the two regulations. When it comes to the effect on the police’s use of FRT for law enforcement purposes, this thesis finds that the police have no bigger reason for worry. The exceptions make a myriad of otherwise prohibited uses of real-time FRT permissible, and the use of post-FRT is not regulated in the act. The second question analyses the problems with the act and the thesis finds that there are essentially four major problems with the act. The exceptions allow for a disproportionate amount of otherwise prohibited uses of FRT, it is too difficult to interpret and the mechanisms for futureproofing are lacking. Furthermore, the interplay with Prüm II must be considered to a greater extent. The third and final question provides three different solutions to the problems. The first solution is to reduce the scope of the exceptions. The second solution is to revise the high-risk provision to make it easier to add new systems. Finally, this thesis finds that the introduction of a separate regulation for law enforcement use, like GDPR & LED, would be a good solution.
3

Role of cholesterol and N-glycosylation in apical sorting of GPI- APs in polarized epithelial FRT cells.

Imjeti, Naga Sailaja 01 July 2011 (has links) (PDF)
Epithelial cells represent the ability to polarize with an apical and basolateral domains which differ markedly in proteins, lipid composition and therefore in function. This asymmetry reflects the ability of epithelial cells to sort newly synthesized proteins and lipid to either cell surface. While the signals responsible for basolateral targeting of the proteins have been clearly understood, the situation regarding the apical sorting of proteins is more obscure. We have previously shown that differently from basolateral GPI-APs oligomerization in the Golgi apparatus is necessary for apical sorting of Glycosylphosphatidylinositol- anchored proteins (GPI-APs). Interestingly this mechanism is conserved in two different kinds of epithelial cells, MDCK and FRT cells, which exhibits a difference in the sorting of GPI-APs. However the precise mechanism leading to this event is not understood. Our previous data demonstrated that simple addition of cholesterol to MDCK cells is necessary and sufficient to induce the oligomerization and apical sorting of a basolateral GPI-AP. Whereas, in this present study in FRT cells we showed that in contrast with MDCK cells cholesterol is not an active player in the regulation of GPI- APs apical sorting. In addition, we also showed that apical and basolateral GPI-APs are not segregated in the Golgi on the bases of the cholesterol content of the surrounding membrane environment. Furthermore, we demonstrated that N- glycosylation of the protein ectodomain is critical for oligomerization and apical sorting of GPI-APs. Our data indicates that at least two mechanisms depending either on cholesterol or on N-glycosylation exist to determine oligomerization in the Golgi and sorting to the apical membrane of GPI-APs.
4

SMN interagit-il avec PFNII pour accomplir une fonction neuronale? : développement d'un système d'intégration dirigé, stable, dans les cellules P19

Germain, Nathalie January 2005 (has links)
No description available.
5

FLP-mediated conditional loss of an essential gene to facilitate complementation assays

Ganesan, Savita 12 1900 (has links)
Commonly, when it is desirable to replace an essential gene with an allelic series of mutated genes, or genes with altered expression patterns, the complementing constructs are introduced into heterozygous plants, followed by the selection of homozygous null segregants. To overcome this laborious and time-consuming step, the newly developed two-component system utilizes a site-specific recombinase to excise a wild-type copy of the gene of interest from transformed tissues. In the first component (the first vector), a wild-type version of the gene is placed between target sequences recognized by FLP recombinase from the yeast 2 μm plasmid. This construct is transformed into a plant heterozygous for a null mutation at the endogenous locus, and progeny plants carrying the excisable complementing gene and segregating homozygous knockout at the endogenous locus are selected. The second component (the second vector) carries the experimental gene along with the FLP gene. When this construct is introduced, FLP recombinase excises the complementing gene, leaving the experimental gene as the only functional copy. The FLP gene is driven by an egg apparatus specific enhancer (EASE) to ensure excision of the complementing cDNA in the egg cell and zygote following floral-dip transformation. The utility of this system is being tested using various experimental derivatives of the essential sucrose-proton symporter, AtSUC2, which is required for photoassimilate transport.
6

Fear resilience in emotiondriven organizations theory (FRT) : En grounded theory studie om känslor hos svenska soldater och officerare före, under och efter stridsrelaterade händelser

Bremer, Christian January 2021 (has links)
Dagens studier inom krigsvetenskap har ofta utgångspunkt i den offentliga, politiska och inom Försvarsmakten interna debatten, speciellt ifråga om Sveriges säkerhetspolitik och våra relationer till andra nationer och internationella organisationer. Begreppsapparaten om militära insatser mildras ofta med tillägg som freds- eller utbildningsinsats men oavsett vilken internationell organisation som föranleder den militära insatsen så är undersökningar om stridsrelaterade händelser ofta relaterade till vilken påverkan som de har på beslutsfattning och chefens ledarskap. Det finns i dagsläget en avsaknad av kvalitativa studier på lägre nivå inom Försvarsmakten avseende hur soldater och officerare påverkas känslomässigt före, under och efter stridsrelaterade händelser.  Studien utgår från djupintervjuer med soldater och officerare med grounded theory som metod. Den fokuserar på hur svenska soldater och officerare påverkas av stridsrelaterade händelser och hur denna erfarenhet i sin tur påverkar militära organisationer. Syftet med denna studie är att utforska och förstå det militära våldets innersta beståndsdelar.    Resultatet visar att olika rädslor påverkar organisationen positivt eller negativt samt förstärks genom alla ledningsnivåer. Stridserfarna soldater och officerare har en större förmåga att reglera sin rädsla och deras rädsla är större inför en strid än under och efter striden. Studien kompletterar och förstärker tidigare israelisk forskning och visar att även svenska stridserfarna soldater och officerares största rädsla före, under och efter strid är att svika sina kamrater (letting others down).
7

Deletion Analysis of the Sinorhizobium meliloti Genome

Milunovic, Branislava 10 1900 (has links)
<p>The <em>Sinorhizobium meliloti</em> genome consists of 6204 predicted protein-coding regions of which approximately 2000 are proteins of unknown function (PUFs). To identify functions of <em>S. meliloti</em> PUFs, we employed the FRT/Flp recombination system to delete large gene clusters and then screened for phenotypes. Large-scale deletions have been mainly used to define minimal gene sets that contain only those genes that are essential and sufficient to sustain a functioning cell. To adapt FRT/Flp for use in <em>S. meliloti</em>, we used an already constructed pTH1522-derived integration gene library of the <em>S. meliloti</em> genome (pTH1522 carries a single FRT site). A second FRT site was inserted at defined locations in the genome through integration of a second plasmid (pTH1937) that also carries a single FRT site. Here we outline how this Flp/FRT system was used to delete defined regions and hence generate multiple gene knock-out mutants. This system was used to delete 32 and 56 defined regions from the 1340 Kb pSymA and 1678 Kb pSymB megaplasmid, respectively. The structures of the resulting megaplasmid deletion mutants were confirmed by PCR analysis. Carbohydrate and nitrogen utilization phenotypes were associated with the deletion of specific regions. Deleting large, regions of the genome helped us to identify phenotypes such as inability to grow on minimal media with fucose, maltotriose, maltitol, trehalose, palatinose, lactulose and galactosamine as sole carbon source. For several FRT-flanked regions, few or no recombinants were recovered which suggested the presence of essential genes. Through this strategy, two essential genes <em>tRNA<sup>arg</sup> </em>and<em> engA</em> located on the pSymB and three toxin/antitoxin-like systems, <em>sma0471</em>/<em>sma0473</em>, <em>sma2105</em> and <em>sma2230</em>/<em>sma2231</em> on pSymA megaplasmid were identified.</p> / Doctor of Philosophy (PhD)
8

Initial guess and optimization strategies for multi-body space trajectories with application to free return trajectories to near-Earth asteroids

Bradley, Nicholas Ethan 23 October 2014 (has links)
This concept of calculating, optimizing, and utilizing a trajectory known as a ``Free Return Trajectory" to facilitate spacecraft rendezvous with Near-Earth Asteroids is presented in this dissertation. A Free Return Trajectory may be defined as a trajectory that begins and ends near the same point, relative to some central body, without performing any deterministic velocity maneuvers (i.e., no maneuvers are planned in a theoretical sense for the nominal mission to proceed). Free Return Trajectories have been utilized previously for other purposes in astrodynamics, but they have not been previously applied to the problem of Near-Earth Asteroid rendezvous. Presented here is a series of descriptions, algorithms, and results related to trajectory initial guess calculation and optimal trajectory convergence. First, Earth-centered Free Return Trajectories are described in a general manner, and these trajectories are classified into several families based on common characteristics. Next, these trajectories are used to automatically generate initial conditions in the three-body problem for the purpose of Near-Earth Asteroid rendezvous. For several bodies of interest, example initial conditions are automatically generated, and are subsequently converged, resulting in feasible, locally-optimal, round-trip trajectories to Near-Earth Asteroids utilizing Free Return Trajectories. Subsequently, a study is performed on using an unpowered flyby of the Moon to lower the overall DV cost for a nominal round-trip voyage to a Near-Earth Asteroid. Using the Moon is shown to appreciably decrease the overall mission cost. In creating the formulation and algorithms for the Lunar flyby problem, an initial guess routine for generic planetary and lunar flyby tours was developed. This continuation algorithm is presented next, and details a novel process by which ballistic trajectories in a simplistic two-body force model may be iteratively converged in progressively more realistic dynamical models until a final converged ballistic trajectory is found in a full-ephemeris, full-dynamics model. This procedure is useful for constructing interplanetary transfers and moon tours in a realistic dynamical framework; an interplanetary and an inter-moon example are both shown. To summarize, the material in this dissertation consists of: novel algorithms to compute Free Return Trajectories, and application of the concept to Near-Earth Asteroid rendezvous; demonstration of cost-savings by using a Lunar flyby; and a novel routine to transfer trajectories from a simplistic model to a more realistic dynamical representation. / text
9

High angular resolution diffusion-weighted magnetic resonance imaging: adaptive smoothing and applications

Metwalli, Nader 07 July 2010 (has links)
Diffusion-weighted magnetic resonance imaging (MRI) has allowed unprecedented non-invasive mapping of brain neural connectivity in vivo by means of fiber tractography applications. Fiber tractography has emerged as a useful tool for mapping brain white matter connectivity prior to surgery or in an intraoperative setting. The advent of high angular resolution diffusion-weighted imaging (HARDI) techniques in MRI for fiber tractography has allowed mapping of fiber tracts in areas of complex white matter fiber crossings. Raw HARDI images, as a result of elevated diffusion-weighting, suffer from depressed signal-to-noise ratio (SNR) levels. The accuracy of fiber tractography is dependent on the performance of the various methods extracting dominant fiber orientations from the HARDI-measured noisy diffusivity profiles. These methods will be sensitive to and directly affected by the noise. In the first part of the thesis this issue is addressed by applying an objective and adaptive smoothing to the noisy HARDI data via generalized cross-validation (GCV) by means of the smoothing splines on the sphere method for estimating the smooth diffusivity profiles in three dimensional diffusion space. Subsequently, fiber orientation distribution functions (ODFs) that reveal dominant fiber orientations in fiber crossings are then reconstructed from the smoothed diffusivity profiles using the Funk-Radon transform. Previous ODF smoothing techniques have been subjective and non-adaptive to data SNR. The GCV-smoothed ODFs from our method are accurate and are smoothed without external intervention facilitating more precise fiber tractography. Diffusion-weighted MRI studies in amyotrophic lateral sclerosis (ALS) have revealed significant changes in diffusion parameters in ALS patient brains. With the need for early detection of possibly discrete upper motor neuron (UMN) degeneration signs in patients with early ALS, a HARDI study is applied in order to investigate diffusion-sensitive changes reflected in the diffusion tensor imaging (DTI) measures axial and radial diffusivity as well as the more commonly used measures fractional anisotropy (FA) and mean diffusivity (MD). The hypothesis is that there would be added utility in considering axial and radial diffusivities which directly reflect changes in the diffusion tensors in addition to FA and MD to aid in revealing neurodegenerative changes in ALS. In addition, applying adaptive smoothing via GCV to the HARDI data further facilitates the application of fiber tractography by automatically eliminating spurious noisy peaks in reconstructed ODFs that would mislead fiber tracking.
10

Využití obrazové spektroskopie pro monitoring zátěže vegetace polutanty obsaženými v půdním substrátu Sokolovské hnědouhelné pánve / Application of imaging spectroscopy in monitoring of vegetation stress caused by soil pollutants in the Sokolov lignite basin

Mišurec, Jan January 2018 (has links)
Forests can be considered as one of the most important Earth's ecosystems not only because of oxygen production and carbon sequestration via photosynthesis, but also as a source of many natural resources (such as wood) and as a habitat of many specific plants and animals. Monitoring of forest health status is thus crucial activity for keeping all production and ecosystem functions of forests. The main aim of the thesis is development of an alternative approach for forest health status based on airborne hyperspectral data (HyMap) analysis supported by field sampling. The proposed approach tries to use similar vegetation parameters which are used in case of the current methods of forest health status assessment based on field inspections. It is believed that importance of such new methods will significantly increase in the time when the planned satellite hyperspectral missions (e.g. EnMap) will move into operational phase. The developed forest health monitoring approach is practically demonstrated on mature Norway spruce (Picea abies L. Karst) forests of the Sokolov lignite basin which were affected by long-term coal mining and heavy industry and therefore high variability of forest health status was assumed in this case. Two leaf level radiative transfer models were used for simulating spectral...

Page generated in 0.0229 seconds